tag:blogger.com,1999:blog-88195828717866103052024-03-14T04:40:55.240-04:00HighLine PolycarbonateTechnical discussions relating to Polycarbonate Sheet and Film by HighLine Polycarbonate LLCUnknownnoreply@blogger.comBlogger45125tag:blogger.com,1999:blog-8819582871786610305.post-7882638514070260892014-08-11T12:52:00.001-04:002014-08-11T13:00:28.389-04:00Polycarbonate – Flammability<div class="separator" style="clear: both; text-align: center;">
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<span style="color: #262626;">At HighLine Polycarbonate LLC, we receive a lot of questions relating to
material flammability. These questions
often occur because of the wide range of tests relating to flammability and the
limited information available from manufacturers. In this blog post we will discuss some of the
most common test methods and what they mean.
It should be recognized that there are many local and national
regulations that refer to different test methods and that we cannot cover all
of these in a single post. In
particular, we have decided not to attempt to cover building regulations due to
the multitude of local codes. Instead we
have concentrated on the transportation industry.<o:p></o:p></span></div>
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<span style="color: #262626;"><b>UL.94</b><o:p></o:p></span></div>
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<span style="color: #262626;">The most common method of defining polycarbonate sheet flammability
properties is UL.94; this test method was developed by Underwriters
Laboratories in the USA.<o:p></o:p></span></div>
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<span style="color: #262626;">There are multiple levels of flammability:<o:p></o:p></span></div>
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<span style="color: #262626;">HB – A piece of the material to be tested is held horizontally, a flame is
applied to one end of the material for 30 seconds.<span style="mso-spacerun: yes;"> </span>When the flame is removed the material must
extinguish before the flame travels 75mm along the material.<o:p></o:p></span></div>
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<span style="color: #262626;">V2 – A piece of the material to be tested is held vertically, a flame is
applied to the material for 10 seconds.<span style="mso-spacerun: yes;">
</span>When the flame is removed, the material must not burn for more than 30
seconds.<o:p></o:p></span></div>
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<span style="color: #262626;">V1 – This test is the same as for V2, with the additional requirement that
the specimen must not drip flaming particles that ignite cotton placed under
the test specimen.<o:p></o:p></span></div>
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<span style="color: #262626;">V0 – This test is the same as for V1, with the additional requirement that
the material must not burn for more than 10 seconds.<o:p></o:p></span></div>
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<span style="color: #262626;"><span style="mso-spacerun: yes;"> </span>The easiest of these tests to pass
is the HB test and the hardest test to pass is V0.<span style="mso-spacerun: yes;"> </span>As an indication, polycarbonate, without any
flame retardant additives, would pass the tests as shown in the table
below.<span style="mso-spacerun: yes;"> </span>Please note that these figures
are only be used for information and test certificates should be obtained from
your polycarbonate sheet supplier.<o:p></o:p></span></div>
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<span style="color: #262626;">HB<span style="mso-tab-count: 1;"> </span>0.060” or thicker<o:p></o:p></span></div>
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<span style="color: #262626;">V2<span style="mso-tab-count: 1;"> </span>0.125” or thicker<o:p></o:p></span></div>
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<span style="color: #262626;">V1<span style="mso-tab-count: 1;"> </span>0.1875” or thicker<o:p></o:p></span></div>
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<span style="color: #262626;">V0<span style="mso-tab-count: 1;"> </span>0.25” or thicker<o:p></o:p></span></div>
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<span style="color: #262626;">As can be seen, the thicker the polycarbonate, the more resistance it is to
the flammability tests.<span style="mso-spacerun: yes;"> </span><o:p></o:p></span></div>
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<span style="color: #262626;">If the design specification calls for a V0 rating at 0.125” thickness,
standard polycarbonate will not be able to meet the specification.<span style="mso-spacerun: yes;"> </span>In this case, flame retardant polycarbonate
sheets would need to be considered.<span style="mso-spacerun: yes;">
</span>Alternatively, a thicker piece of polycarbonate could be specified.<span style="mso-spacerun: yes;"> </span>Using a thicker piece of polycarbonate would
probably be cheaper if the design allows; the material would also be much more
available.<o:p></o:p></span></div>
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<span style="color: #262626;">Within the UL.94 standard there are two additional higher levels of
flammability, 5VB and 5VA.<span style="mso-spacerun: yes;"> </span>As these
ratings are not as common we will not go into details here.<span style="mso-spacerun: yes;"> </span>However, a quick internet-search will reveal
details on these tests.<o:p></o:p></span></div>
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<span style="color: #262626;"><b>Aircraft
specifications – FAR 25.853</b></span><span style="color: #262626;"><o:p></o:p></span></div>
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<span style="color: #262626;">The FAA (Federal Aviation Administration) developed a standard for materials
to be used in aircraft cabin and cargo compartments.<span style="mso-spacerun: yes;"> </span>This standard is known as FAR.25.853.<span style="mso-spacerun: yes;"> </span>For polycarbonate sheet there are two
relevant parts FAR 25.853a and FAR 25.853d relating to flammability. <o:p></o:p></span></div>
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<span style="color: #262626;">FAR 25.853a measures the resistance of material to flames.<span style="mso-spacerun: yes;"> </span>The material is held vertically and a Bunsen
burner is applied for (i) 60 Seconds and (ii)12 seconds.<span style="mso-spacerun: yes;"> </span>Three items are measured:<o:p></o:p></span></div>
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<span style="color: #262626;">The flame time – the time that the specimen continues to burn after the
flame is removed.<o:p></o:p></span></div>
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<span style="color: #262626;">The drip flame time – the time that any flaming material continues to flame
after falling from the material.<o:p></o:p></span></div>
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<span style="color: #262626;">The burn length – the distance from the original specimen’s edge to the
farthest evidence of damage to the specimen.<o:p></o:p></span></div>
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<span style="color: #262626;">To pass the tests the material must achieve the following:<o:p></o:p></span></div>
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<br />
Test Flame time (sec) Drip flame time (sec) Burn length<br />
<br />
(i) 60 second < 15 < 3 6"<br />
(ii) 12 second < 15 < 5 8"</div>
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<span style="color: #262626;">We are aware of a number of transparent polycarbonate sheets with flame
retardant additives that can pass this test.<o:p></o:p></span></div>
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FAR 25.853d consists of two tests.<span style="mso-spacerun: yes;"> </span>The first, the OSU (Ohio State University)
Rate of Heat release tries to limit the possibility that materials will become
rapidly involved in a fire or contribute to an existing fire.<span style="mso-spacerun: yes;"> </span>The rate of heat release is measured using
the principle of oxygen consumption using the OSU calorimeter and the test
method is published under ASTM E906.<span style="mso-spacerun: yes;"> </span>The
standard requires that the total heat release within the first 2 minutes is
<= 65kW per square meter and that the Peal Heat Release Rate is <= 65KW
per square meter.<span style="mso-spacerun: yes;"> </span>In data sheets for
flame retardant polycarbonate sheets, if a material passes this test it is often
written a FAR 25.853a OSU 65/65.<o:p></o:p></div>
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At this stage we are not aware of any transparent
polycarbonate sheets that can pass OSU 65/65 even with flame retardant
additives.<span style="mso-spacerun: yes;"> </span>We are aware of opaque
polycarbonate sheet that can pass this test such as the Lexan XHR.6000 and the
halogen free Ultem 1668A.<o:p></o:p></div>
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The second test in FAR 25.853d is the smoke density test,
which is similar to ASTM E.662 (which we shall discuss later).<span style="mso-spacerun: yes;"> </span>This test measures the amount of smoke that
is generated, which could prevent passengers escaping in a fire situation.<span style="mso-spacerun: yes;"> </span>To pass this test the 4.0 minute smoke
density Ds (4 min) <= 200.<span style="mso-spacerun: yes;"> </span>A number
of transparent polycarbonate sheets, with flame-retardants, are able to pass
this test.<o:p></o:p></div>
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To pass all elements of FAR 25.853 a material must list the
following:<o:p></o:p></div>
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FAR 25.853a (i) 60 seconds<span style="mso-tab-count: 2;"> </span><span style="mso-tab-count: 1;"> </span>Pass<o:p></o:p></div>
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FAR 25.853a (ii) 12 seconds<span style="mso-tab-count: 2;"> </span><span style="mso-tab-count: 1;"> </span>Pass<o:p></o:p></div>
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FAR 25.853d Rate of Heat Release<span style="mso-tab-count: 1;"> </span><span style="mso-tab-count: 1;"> </span>OSU 65/65<o:p></o:p></div>
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PAR 25.853d Smoke Density Ds(4min)<span style="mso-tab-count: 1;"> </span><= 200<o:p></o:p></div>
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<b>Rail car
specifications – 49 CFR Part 238</b><o:p></o:p></div>
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The FRA (Federal Railroad Administration) developed a
standard for materials to be used in rail car applications in the US.<span style="mso-spacerun: yes;"> </span>The part of this standard that deals with
flammability is known as 49 CFR Part 238.<span style="mso-spacerun: yes;">
</span>For polycarbonate sheet Appendix B of this standard requires two tests,
ASTM E.162 and ASTM E.662.<o:p></o:p></div>
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ASTM E162 provides a measure of flame spread and heat
evolution.<span style="mso-spacerun: yes;"> </span>The maximum value to pass
this test Is <= 100<o:p></o:p></div>
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ASTM E.662 is similar to the test used for the aircraft
industry to measure smoke density.<span style="mso-spacerun: yes;"> </span><o:p></o:p></div>
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To pass this test, the smoke density after 1.5 minute Ds(1.5
min) <= 100 and the smoke density after 4 minutes Ds (4 min) <= 400.<span style="mso-spacerun: yes;"> </span>It can be seen that the 4 minute test for the
FRA is not a severe as for the FAA.<o:p></o:p></div>
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In general, some of the thicker polycarbonate transparent
sheet can pass these tests without the need for flame-retardants.<span style="mso-spacerun: yes;"> </span>However, test certificates must always be
provided by the manufacturer.<span style="mso-spacerun: yes;"> </span><o:p></o:p></div>
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<b>Overview</b><o:p></o:p></div>
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<br /></div>
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Transparent polycarbonate sheet without flame retardant
additives has a reasonable level of flame resistance, particularly as the
thickness increases.<span style="mso-spacerun: yes;"> </span>It is able to pass
some of the UL.94 tests and can pass some of the Smoke Density, Fame spread and
heat release tests required by various transport administrations.<span style="mso-spacerun: yes;"> </span><o:p></o:p></div>
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Where these properties are not sufficient, flame retardant
additives can be used to improve the properties, but these add to the
price.<span style="mso-spacerun: yes;"> </span>Some significant improvements can
be made while still allowing the material to remain transparent.<o:p></o:p></div>
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With some of the more demanding specifications, higher doses
of more complex flame retardant additives are required.<span style="mso-spacerun: yes;"> </span>Achieving some of the higher specifications
are not possible while also retaining the transparency of the material.<span style="mso-spacerun: yes;"> </span>Also, adding these flame retardant additives
can impact other properties of the polycarbonate sheet.<o:p></o:p></div>
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<br />
<div class="MsoNormal">
<b><u>Preventing
delamination in transparent armor.</u></b><o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifH94kiP_JjAzxoWOCtorWq_vljVm4vA7HKMH_NvVr4DdDBq2ybzWDhry8KT_D4HOIYTULl5KRXS8Se8cjy6IjWcmEc8BsdLUiDskGQiP4x0W-7dIRqxmvMVypJVquT0ahHSINA8EE5xc/s1600/Humvee+color+300x200.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEifH94kiP_JjAzxoWOCtorWq_vljVm4vA7HKMH_NvVr4DdDBq2ybzWDhry8KT_D4HOIYTULl5KRXS8Se8cjy6IjWcmEc8BsdLUiDskGQiP4x0W-7dIRqxmvMVypJVquT0ahHSINA8EE5xc/s1600/Humvee+color+300x200.jpg" /></a></div>
<br />
<div class="MsoNormal">
Delamination of transparent armor is an ongoing
problem. This blog post aims to explore
the subject using some technical theory, with the aim of presenting simple
solutions to minimize the problem. The
proper design of the laminate, manufacturing of the laminate and selection of
materials can all lead to a significant increase in the life of the
laminate. This post will explore some of
the issues and provide recommendations.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
To start looking at the problem of delamination we want to
start with a mathematical analysis of the problem and we therefore used a
simple formula to model the stresses that cause delamination. The simplified formula is taken from the
paper “Thermal Stress in Bonded Joints” by W.T.Chen and C.W.Nelson. It examines the thermal stresses in a bonded
joint between two materials using an adhesive interlayer. The paper also gives a more complex formula for
three layers instead of two; for readers who would like to examine the formula
for three layers, the paper is easy to find by entering the title of the paper
in Google. For more complex structures
involving more than three layers, the formulas can be derived using the same
principles. The paper shows how the
following formula is derived, but for this blog post, we will just take the
formula as given. For those that prefer
to see the derivation, the paper is available to read. It is recognized that equating a laminate to
a bonded joint is somewhat simplistic, but it does give a good starting point
to analyze the problem.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The formula presented in the paper for calculating stresses
in a two-layer joint is: <o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b><span style="font-family: 'MS 明朝';">Τ</span>=</b><b><span style="font-family: 'Lucida Grande';"> <u>(</u></span></b><b><u><span style="font-family: 'MS 明朝';">α<sub>1 </sub></span></u></b><b><u><sub><span style="font-family: 'Lucida Grande';">–</span></sub></u></b><b><u><sub><span style="font-family: 'MS 明朝';"> </span></sub></u></b><b><u><span style="font-family: 'MS 明朝';">α<sub>2</sub>) </span></u></b><u><span style="font-family: Arial;">T</span></u><u>
G sinh (β x)<o:p></o:p></u></div>
<div class="MsoNormal" style="text-indent: .5in;">
β η cosh (β L)<o:p></o:p></div>
<div class="MsoNormal" style="text-indent: .5in;">
<br /></div>
<div class="MsoNormal" style="text-indent: .5in;">
<br /></div>
<div class="MsoNormal">
β<sup>2</sup> = <u>G</u>
[ (1/(E<sub>1</sub> t<sub>1</sub>) + (1/(E<sub>2</sub> t<sub>2</sub>) ]<o:p></o:p></div>
<div class="MsoNormal">
η<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Τ = Shear
Stress (Pa)<o:p></o:p></div>
<div class="MsoNormal">
<b><span style="font-family: 'MS 明朝';">α<sub>1 </sub></span></b>= Thermal expansion
coefficient of layer 1 (/C)<o:p></o:p></div>
<div class="MsoNormal">
<b><span style="font-family: 'MS 明朝';">α<sub>2 </sub></span></b>= Thermal expansion
coefficient of layer 2 (/C)<o:p></o:p></div>
<div class="MsoNormal">
T = Temperature
change (C)<o:p></o:p></div>
<div class="MsoNormal">
x = Distance
from center of joint (mm)<o:p></o:p></div>
<div class="MsoNormal">
L = Distance
from center of joint to end of joint (mm)<o:p></o:p></div>
<div class="MsoNormal">
G = Shear
modulus of interlayer (Pa)<o:p></o:p></div>
<div class="MsoNormal">
η = Thickness
of interlayer (mm)<o:p></o:p></div>
<div class="MsoNormal">
E<sub>1</sub> =
Elastic modulus of layer 1 (mm)<o:p></o:p></div>
<div class="MsoNormal">
E<sub>2</sub> =
Elastic modulus of layer 2 (mm)<o:p></o:p></div>
<div class="MsoNormal">
t<sub>1</sub> =
Thickness of layer 1 (mm)<o:p></o:p></div>
<div class="MsoNormal">
t<sub>2</sub> =
Thickness of layer 2 (mm)<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The formula can be used to calculate the Shear stress at any
point in the laminate from the center to the edge. When x = L at the edge of the laminate, the
shear stress will be maximum, and:<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b><span style="font-family: 'MS 明朝';">Τ<sub>max</sub>
</span>=</b><b><span style="font-family: 'Lucida Grande';"> <u>(</u></span></b><b><u><span style="font-family: 'MS 明朝';">α<sub>1 </sub></span></u></b><b><u><sub><span style="font-family: 'Lucida Grande';">–</span></sub></u></b><b><u><sub><span style="font-family: 'MS 明朝';"> </span></sub></u></b><b><u><span style="font-family: 'MS 明朝';">α<sub>2</sub>)T G</span></u></b><o:p></o:p></div>
<div class="MsoNormal">
<span style="font-family: 'Lucida Grande';">βη</span><o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
This formula is somewhat intuitive. The stress will be greater if the difference
in coefficient of thermal expansion of the two materials <b><span style="font-family: 'MS 明朝';">α<sub>1 </sub></span></b><b><sub><span style="font-family: 'Lucida Grande';">–</span></sub></b><b><sub><span style="font-family: 'MS 明朝';"> </span></sub></b><b><span style="font-family: 'MS 明朝';">α<sub>2</sub></span></b>
is large. The stress will also be
greater as the Temperature change T increases.
Also if the interlayer is thicker (<span style="font-family: 'Lucida Grande';">η)</span>, it allows the stresses caused by the expansion and
contraction of the materials to be reduced.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The first thing to note is that transparent armor is often
exposed to environmental temperature changes in military applications. ATPD.2352 requires testing over a temperature
range of -31 C to +60C or a 91 degree C temperature range. Although the laminate will not see this range
in temperature every day, it is certainly possible that it could experience
these conditions during its life. <o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
It should be noted that if normal operating temperature is
say 15 C, this is not the temperature that has zero stresses. The temperature that has zero stresses is
much closer to the temperature during fabrication the polyurethane sets and
bonds to the glass and polycarbonate.
Depending upon the polyurethane, this temperature could be 80 C or
higher. Selection of the polyurethane
therefore has some impact on the maximum stresses that a laminate will
see. A polyurethane that sets at 120 C
will lead to much higher stresses than a polyurethane that sets up at 80C.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
To illustrate this point, the maximum stress will occur in a
laminate when the temperature of the laminate is the lowest, in the case of
ATPD.2352 this will be -31C. Using a
polyurethane that sets up at 120C rather than 80C will give about (120 - -31) /
(80 - - 31) = 151/ 111 or about 36% more maximum stress in the laminate at the
interface.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
It should be remembered in the selection of polyurethane,
that choosing a low melting polyurethane to minimize stresses should be done
with careful consideration of the operating and storage environment that the
laminates will see. It is extremely
counterproductive to have solar heating leading to the melting of the
polyurethane, as this will lead to melting delamination rather than thermal
stress delamination.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
This problem can be made even worse by poor laminating
control. Polycarbonate expands or
contracts a lot more than glass. If the
laminate is not uniform in temperature throughout the entire thickness at the
time the Polyurethane is setting up, it is possible that some of the
polycarbonate could be at a higher temperature at its core at the time the surface
is bonding to the polyurethane. This
increased core temperature can cause increase stresses at the interface of the
polyurethane. Proper manufacturing that
allows the temperature of the laminate to stabilize throughout, just above the
temperature where the polyurethane sets up can significantly reduce stresses. <o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
One elegant solution to the problem is to use radio
frequency lamination to lower the temperatures of the polycarbonate and glass
at the time of lamination. This type of
lamination heats only the polyurethane interlayer and can therefore reduce the
zero stress temperature well below the temperature achieved by conventional
autoclaves. We can provide laminators with
information on this process if requested.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The other item to note from the formula is that the
thickness of the polyurethane is important.
Using a thicker polyurethane can allow the stresses to be significantly
reduced. If we consider that case where
6mm glass is bonded to 6mm polycarbonate, using the above formula the stresses
can be reduced from 13.7 MPa to 6.9 MPa if using 0.075mm polyurethane rather
than 0.025mm polyurethane with a temperature swing of 111 degrees C.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Decreasing the amount of thermal stress generated will
significantly affect the life of the laminate.
Halving the stress, as in the above example, could be the difference
between delamination and no delamination.
The other factor that affects delamination is the adhesion between the
polyurethane and the other materials – glass and polycarbonate. Delamination will occur at the weakest of
these joints, which is typically the polycarbonate, polyurethane interface. Delamination will occur when the forces due
to the thermal stresses are stronger than the adhesion of the polyurethane to
the polycarbonate or glass. <o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
One area where we have started to have some positive effects
in reducing delamination in high-end laminates is increasing the bonding
between the polyurethane and the polycarbonate.
We have been tackling this area in two ways, firstly by correct selection
of the polyurethane and secondly by modifying the chemistry of the
polycarbonate. We have recently made
available an enhanced grade of polycarbonate that has significantly higher bond
strength to polyurethane.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The next area that should be considered is the area of
laminate design. In some cases laminates
are configured only to pass ballistics specifications and little consideration
is give to how the configuration may affect stresses and delamination. To illustrate this point we will use the
three-layer formula developed in the paper that we discussed earlier. Due to the formula’s length, we will not
present it here, but again the paper can easily be found.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
In the first case we will consider a two-layer laminate
consisting of 6mm Polycarbonate bonded to 6mm Glass using a 0.025 mm
polyurethane. The change in temperature
that the laminate will be exposed to will be considered to be 100 degrees
C. We have calculated that the maximum
stress will be 12.3 MPa.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
If we then change the laminate configuration, with the aim
of keeping the total thickness the same, to 3mm Polycarbonate, 3mm
Polycarbonate and 6mm Glass, the total amount of polycarbonate and glass will
remain the same. In this configuration the maximum stress between the glass and
the polycarbonate will be 11.70 MPa.
Although the difference may not seem to be much, it is a 5% reduction in
the stress. In a laminate that is close
to the point of delamination, reducing the stresses by 5% could be enough to
significantly increase the life of the laminate or even prevent delamination
occurring. Reducing thermal stresses,
particularly when done in conjunction with increasing the bond strength between
the polyurethane and the polycarbonate, can be very effective in decreasing
delamination and increasing laminate life.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Other factors do affect delamination including edge seals,
chemical attack and edge finishing, but the aim of this article is mainly to
look at some of the factors associated with delamination caused by thermal
stresses.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
The key points to minimize thermal stresses and reduce
delamination are:<o:p></o:p></div>
<div class="MsoListParagraphCxSpFirst" style="mso-list: l0 level1 lfo1; text-indent: -.25in;">
<!--[if !supportLists]--><span style="font-family: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol;">·<span style="font-family: 'Times New Roman'; font-size: 7pt;">
</span></span><!--[endif]-->Select the correct thickness of polyurethane to
minimize thermal stresses<o:p></o:p></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l0 level1 lfo1; text-indent: -.25in;">
<!--[if !supportLists]--><span style="font-family: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol;">·<span style="font-family: 'Times New Roman'; font-size: 7pt;">
</span></span><!--[endif]-->Select the correct type of polyurethane to
minimize stresses and increase bonding, while also considering environmental
conditions that the laminate will be exposed to.<o:p></o:p></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l0 level1 lfo1; text-indent: -.25in;">
<!--[if !supportLists]--><span style="font-family: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol;">·<span style="font-family: 'Times New Roman'; font-size: 7pt;">
</span></span><!--[endif]-->Optimize autoclave conditions to reduce thermal
stresses.<o:p></o:p></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l0 level1 lfo1; text-indent: -.25in;">
<!--[if !supportLists]--><span style="font-family: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol;">·<span style="font-family: 'Times New Roman'; font-size: 7pt;">
</span></span><!--[endif]-->Improve the bond strength between the
polycarbonate and the polyurethane by using an enhanced polycarbonate designed
to increase bond strength in transparent armor.<o:p></o:p></div>
<div class="MsoListParagraphCxSpLast" style="mso-list: l0 level1 lfo1; text-indent: -.25in;">
<!--[if !supportLists]--><span style="font-family: Symbol; mso-bidi-font-family: Symbol; mso-fareast-font-family: Symbol;">·<span style="font-family: 'Times New Roman'; font-size: 7pt;">
</span></span><!--[endif]-->Design the laminate configuration to minimize
stresses in addition to achieve ballistics requirements.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<!--EndFragment-->Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-8819582871786610305.post-88069083969160670722012-10-21T17:33:00.001-04:002012-10-21T17:36:42.434-04:00Transparent Polyamide sheet compared to Polycarbonate Sheet<div class="separator" style="clear: both; text-align: center;">
</div>
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXeATVWBF0SBhGdm0CBpXuhYoLA-HeIsILNj0CJcLEpD8Vx2wADi-f_59evn4sr0HGYztbq4Q9f-u6KO-2yX1O_aAjkxtlXg3-KQMQevITdm_z7nqrqbc2bInRhxjQo6eqUi90-0kmpAQ/s1600/MRAP2.bmp" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="213" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXeATVWBF0SBhGdm0CBpXuhYoLA-HeIsILNj0CJcLEpD8Vx2wADi-f_59evn4sr0HGYztbq4Q9f-u6KO-2yX1O_aAjkxtlXg3-KQMQevITdm_z7nqrqbc2bInRhxjQo6eqUi90-0kmpAQ/s320/MRAP2.bmp" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Transparent Armor Window</td></tr>
</tbody></table>
Many people are aware of Polycarbonate sheet, PETG sheet and Acrylic sheet, but there is now a new material that has entered the transparent sheet market - Polyamide.<br />
<br />
Polyamide is certainly higher in price than other transparent sheets, but it has an interesting range of properties that make it suitable for some technically demanding applications.<br />
<br />
Like Polycarbonate, Polyamide can be used to make very high quality optical grade clear sheet. In fact the light transmission is 90% compared to 89% for Polycarbonate. Sheets of the same size as Polycarbonate can be easily manufactured. Also, Polyamide is almost as unbreakable at Polycarbonate which means it can withstand environments that would damage polymer sheets made out of Acrylic.<br />
<br />
Where Polyamide really excels is in properties such as the heat distortion temperature, tensile modulus, density and solvent resistance. We will look at each of these in turn and compare them to the other Polymers.<br />
<br />
<b>Heat distortion temperature.</b><br />
<b><br /></b>
<b><br /></b>
Material Heat distortion temperature (C) Glass transition temperature (C)<br />
Acrylic 95 110<br />
Polycarbonate 137 148<br />
Polyamide 180 190<br />
<br />
These figures show that Polyamide can withstand much higher temperatures than both Acrylic and Polycarbonate before they will start to distort under a load. In many applications, the heat distortion temperature is not an issue, but occasionally the part must be able to operate in higher temperature environments without distorting. In these applications, Polyamide is an excellent option.<br />
<br />
<b>Tensile modulus</b><br />
<b><br /></b>
Material Tensile modulus (psi)<br />
Polycarbonate 348,000<br />
Polyamide 232,000<br />
<br />
Polycarbonate is a very flexible material, much more so than Acrylic which is rigid by comparison. This flexibility makes it very useful in applications such as security glazing and transparent armor. While Polyamide grades are available with a number of different Tensile modulus characteristics, the one that HighLine Polycarbonate LLC is currently using to make sheet has a lower tensile modulus than even Polycarbonate, making the Polyamide sheet more flexible than Polycarbonate sheet. This property means that in certain configurations, it can be a better material for bullet resistant applications than Polycarbonate. Of course there is a price-performance balance that means that Polyamide is not suitable for all applications.<br />
Where flexibility is needed, Polyamide is certainly an option to be considered.<br />
<br />
<b>Density</b><br />
<br />
Polycarbonate and Acrylic have similar densities of around 1200 kg/m3. Polyamide has a density of around 1060 kg/m3. This means that Polyamide is about 10% lighter. Where weight is important, Polyamide is an option.<br />
<br />
<b>Solvent resistance</b><br />
<b><br /></b>
Polycarbonate, while very resistant to a number of chemicals, does not perform well when exposed to certain other chemicals such as Ketones. One of the strengths of Polyamide is that it has exceptional solvent resistance performance. As well as being resistant to Ketones, Polyamide is not attacked by most fuels, oils and lubricants. This chemical resistant makes it a good choice in transportation and aerospace applications.<br />
<br />
As far as we know, HighLine Polycarbonate is the only manufacturer to currently offer clear Polyamide sheet to the market. If you would like more information on this unique material, please contact us.<br />
<br />
<br />Unknownnoreply@blogger.com5tag:blogger.com,1999:blog-8819582871786610305.post-9154875314999704292012-05-10T15:44:00.001-04:002012-05-10T15:47:26.378-04:00Anti Glare Coatings explained<div class="separator" style="clear: both; text-align: left;">
Anti-glare coatings are different to anti-reflective coatings. Anti-glare coatings are generally produced using an abrasion resistant hard coat with small particles in the coating to give a matte surface. This matte surface stops light being reflected from the sheet surface back to the viewer so that the user's view is not obscured by glare from lighting or the sun.</div>
<div class="separator" style="clear: both; text-align: left;">
One down side to the matte surface is that the light transmission of the sheet is lowered and the view through the sheet is hazy. The more of the matte agent that is put into the sheet the more the glare is reduce, but also the sheet becomes more hazy and the view more obstructed.</div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div class="separator" style="clear: both; text-align: left;">
To illustrate the effect of an anti-glare coating we have taken three pictures of an anti-glare sheet with a 40% gloss level. The 40% gloss is quite a high level of matte agent - we commonly supply product with gloss levels of 60% and as high as 80%. The 80% gloss level is much more transparent but does not reduce the glare as much as the 40% gloss level material.</div>
<div class="separator" style="clear: both; text-align: left;">
<br /></div>
<div class="separator" style="clear: both; text-align: left;">
We are often asked how much does the reduction in gloss level obscure the view through the sheet? The answer depends on what you are trying to view. If you are trying to view something that is a long way away through the sheet, the object is still able to be seen but the view is very blurred. To show this effect, we positioned a typed page only 15" behind the anti-glare sheet. The page is visible but the details are not.</div>
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We then moved the page to 5" behind the sheet. Again the page is visible and you can even start to make out the detail of some of the larger font. 48 Point font is clearly legible, even 28 Point font is just visible, while smaller font can be seen but not read.</div>
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We then moved the typed page to immediately behind the sheet and the page was even touching the sheet. Nearly all of the font, even the smallest can be clearly read. </div>
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When choosing an anti-glare gloss level it is important to test it in your application. The questions that need to be answered are how much do you need to reduce glare and how much haze can you accept. The answers to these questions depend on what environment you are you using the sheet in and what do you need to see through the sheet. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIUJzIDSsBDO2obvdSvbxKARIZgvHTxid1aSjesbVyM5bwzcAYPvkn9uJetoj7UyuFQZGiRSqUI4P-9kZvEJ3wGXnur_3O5rvcnr_GtuxJCAEkNo4KjK3daSQlXqfNxYrX7cbFnzxFCL0/s1600/AG+1.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIUJzIDSsBDO2obvdSvbxKARIZgvHTxid1aSjesbVyM5bwzcAYPvkn9uJetoj7UyuFQZGiRSqUI4P-9kZvEJ3wGXnur_3O5rvcnr_GtuxJCAEkNo4KjK3daSQlXqfNxYrX7cbFnzxFCL0/s1600/AG+1.JPG" /></a> </div>
Photo 1 - Typed page 15" behind the anti-glare sheet<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQuVK8wnt8Y9Tm74I0yT4W9Zc2PulY14Gm44dxAzLmHDYuxfWrJCW7aP-0MxOX1fs9p_Waq12vCjQhDpTO6AmKVjOf_zp6MqGOdlQoPwid-UK3sMWCpOzF-GZZwkWCj_6LMcIJDCjncNQ/s1600/AG2.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQuVK8wnt8Y9Tm74I0yT4W9Zc2PulY14Gm44dxAzLmHDYuxfWrJCW7aP-0MxOX1fs9p_Waq12vCjQhDpTO6AmKVjOf_zp6MqGOdlQoPwid-UK3sMWCpOzF-GZZwkWCj_6LMcIJDCjncNQ/s1600/AG2.JPG" /></a></div>
Photo 2 - Typed page 5" behind the anti-glare sheet<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzfK3dKwdD2JrCoo9kEJM-gx5ii9mcj13-anmFUe9uvGg1bQ4qJlqnsDZrOyi5uT9kp7uPR0gQqkhal3gHvcNlZbmiWrAcR0WSNZwqBvBsQJWxZYCOyR-RXxCzd_5t8qwm7zclc2kja8E/s1600/AG3.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzfK3dKwdD2JrCoo9kEJM-gx5ii9mcj13-anmFUe9uvGg1bQ4qJlqnsDZrOyi5uT9kp7uPR0gQqkhal3gHvcNlZbmiWrAcR0WSNZwqBvBsQJWxZYCOyR-RXxCzd_5t8qwm7zclc2kja8E/s1600/AG3.JPG" /></a></div>
Photo 3 - Typed page immediately behind the anti-glare sheet (touching)Unknownnoreply@blogger.com2tag:blogger.com,1999:blog-8819582871786610305.post-71358386783935493172012-05-08T09:52:00.000-04:002012-05-08T09:56:53.294-04:00Clearfix - Repairing Polycarbonate sheet scratches<iframe allowfullscreen="" frameborder="0" height="315" src="http://www.youtube.com/embed/0N_1wkUIMMw?rel=0" width="560"></iframe><br />
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The above video shows how scratches in both uncoated and abrasion resistant Polycarbonate sheet can be easily repaired using a product developed by 3M and Clearfix Aerospace. The product was initially developed to repair military helicopter windows; however, HighLine Polycarbonate has worked with 3M and Clearfix Aerospace to evaluate and test the product on Polycarbonate sheet used on transparent armor laminates as well as other applications.<br />
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The product works equally well on repairing scratches and other damage on both coated and uncoated Polycarbonate sheet. Not only can the product be used to repair scratches on in service vehicles but it can also be used to repair scratches on production damaged laminates. Laminates that would otherwise need to be scrapped can now be repaired allowing manufacturers and users to significantly reduce costs.<br />
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The product can be purchased from HighLine Polycarbonate LLC as we are now a primary distributor of Clearfix. Potential users should contact us to schedule a demonstration at their facility.Unknownnoreply@blogger.com1tag:blogger.com,1999:blog-8819582871786610305.post-68611146146825448762012-04-17T12:00:00.003-04:002012-04-17T21:42:24.049-04:00LEDs in Polycarbonate<iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.blogger.com/video.g?token=AD6v5dx8q7U3KE5dP_r_InWVmz_pF-N1985I6v_ZQOfoIJefx1NX3e1jZhvVnPtpUXql-tmZOwNFEt1tZsmLMQp2' class='b-hbp-video b-uploaded' frameborder='0'></iframe><div><br /></div><div>This video shows a new process we are developing to laminate ultra thin LEDs between sheets of Polycarbonate. The first sheet in the video shows the LEDs between two sheets of 0.118" thick clear Polycarbonate. The second sheet shows the LEDs between a mirrored piece of 0.177" Polycarbonate and a piece of clear 0.118" Polycarbonate - the LEDs are only visible when they are lit as normally they are hidden by the mirror.</div><div><br /></div><div>The next production trial will use a piece of light diffusing Polycarbonate as the front face in order to diffuse the LED light and prevent "hotspots". We also plan to increase the density of the LEDs. We also plan to use thinner Polycarbonate to make the whole structure 0.118" thick in total.</div><div><br /></div><div>Conventional lamination methods would damage LEDs, but a new technique that we are working on is making these type of products possible. The technique would allow very bright, low weight signs or lighting powered by only a 9 volt supply.</div>Unknownnoreply@blogger.com1tag:blogger.com,1999:blog-8819582871786610305.post-36539119783832908752012-04-02T12:30:00.005-04:002012-04-05T10:15:58.178-04:00Is Polycarbonate Bullet Resistant?We recently came across this video on YouTube. It is certainly one of the more interesting and better produced of the videos about Polycarbonate and bullet resistance. <br /><br /><iframe width="560" height="315" src="http://www.youtube.com/embed/NDSG0I8TFdk" frameborder="0" allowfullscreen></iframe><br /><br />We will concentrate our discussion to the first two rounds fired, the 0.22LR and the 9mm round.<br /><br />Most ballistics certifications for bullet resistant glass constructions, such as UL.752, start their testing with a 9mm Full Metal copper Jacket with a lead core. This bullet weighs 8 grams and has a test velocity of 358 m/s. The 0.22LR in the video has a weight of about a third of this at 2.6 grams and a velocity of around 290 ms.<br />Using our Kinetic Energy formula of Energy = 0.5 x Mass x Velocity x Velocity, the 9mm round has about 4.7 times the energy of the 0.22LR round.<br />For the UL.752 Level 1 test three shots of a 9mm FMJ must be fired at a 12" x 12" target and the shots must land within a 4" triangle area. To pass the test no bullets must pass through the material and no pieces of the material must come off the back with sufficient velocity to damage a cardboard witness plate located a short distance behind the sample.<br />The 12" x 12" test piece is fully supported and will not move during the testing.<br /><br />From the video of the 022LR it is clear that the 0.5" Polycarbonate does not allow the round to pass through. One concern that we would have is that the test piece was not supported, so some of the energy was absorbed by moving the piece when it was hit. That would not be realistic in real life where a window would be supported. Also the test in video did not consider multiple hits in a small area as in the UL.752 Level 1 test. However, it appears likely that Polycarbonate that is supported in a frame could stop 0.22LR rounds at a reasonable thickness - however, without testing in a controlled manner it is not possible to say whether the required thickness is 0.5" or greater.<br /><br />From the video of the 9mm round, two 0.5" pieces of Polycarbonate were clamped together. This test was designed to see if 1.0" of Lexan could stop a 9mm round. We have some similar concerns as for the first test where the test sample was not supported. More importantly the pieces broke free from the clamp and it is not clear whether the second piece was hit straight on or whether the bullet glanced off the piece. We don't think that the video is claiming that a 1.0" piece of Lexan can stop one or more hits from a 9mm round but we would be concerned if someone inferred this from the video. <br /><br />One thing that we do know is the a 0.75" construction made from 1/8" Polycarbonate - 1/2" Cell cast Acrylic - 1/8" Polycarbonate can be tested to UL.752 Level 1 with the 9mm threat and will pass. So a single 1,0" supported layer of Polycarbonate may or may not be effective for stopping 9mm rounds but there are potentially cheaper and lighter options available that will.<br /><br />If you put thick enough piece of Polycarbonate in front of a 9mm round it will eventually stop the round. It just may not be the cheapest or lightest way of doing it, which is why Polycarbonate is not normally tested and approved as a bullet resistant material as a stand alone solution.<br /><br />The video even states that their test is completely unscientific. <br />All of this does not make the video any less interesting or enjoyable. It is also very well produced.Unknownnoreply@blogger.com6tag:blogger.com,1999:blog-8819582871786610305.post-8724167481521505822012-03-20T09:28:00.005-04:002012-03-22T08:04:48.177-04:00Drying Polycarbonate sheet<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaMPuEA46_zb4fWplYAaWDBkjNvFNc7kNQo0y8MQqisSAytXXGAaNtj82UMb-CFrnEAlIwv7hmhomwAq6QT3HmnlCH6OPTUPbP8bG9o53uZoyU3hC0LVayENctoYnzc8p_MQqBRqmNAv4/s1600/Glass+Building+2.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 213px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaMPuEA46_zb4fWplYAaWDBkjNvFNc7kNQo0y8MQqisSAytXXGAaNtj82UMb-CFrnEAlIwv7hmhomwAq6QT3HmnlCH6OPTUPbP8bG9o53uZoyU3hC0LVayENctoYnzc8p_MQqBRqmNAv4/s320/Glass+Building+2.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5721971434486961362" /></a>Polycarbonate sheet readily absorbs moisture from the air. Eventually the water content will reach 0.2% by weight.<div>In most applications this water content is not a problem, however, in applications where you need to process the sheet above a temperature of 250F, this water can vaporize within the sheet during processing and lead to small bubbles forming. As little as 0.05% water can cause these bubbles.</div><div><br /></div><div>Two processes that require the sheet to be heated above 250F are lamination of the Polycarbonate and thermoforming of the Polycarbonate. Both of these processes can have problems with bubbles if the sheet is not dried correctly.</div><div><br /></div><div>To dry the sheet there is a wide range of recommendations that have been published. To dry 0.118" thick sheet it is normally recommended to use an oven set at 250F. The drying time suggestions can range from 6 to 12 hours. We would suggest that the longer time the sheet is dried the better and we would use 12 hours. Other recommendations suggest that a lower oven temperature of 180F can be used but the time must be increased to 24 hours. If your oven is only capable of reaching 180F rather than 250F, you could certainly try this method - however, we are very skeptical of this approach as to drive the water off effectively you really need to be above the boiling point of water.</div><div>As the thickness of the sheet increases, the drying time will increase significantly as the water needs to be removed from the center of the sheet. For 0.236" thick sheet we would recommend 30 hours of drying at 250F and for 0.375" thick sheet we would recommend 40 hours.</div><div><br /></div><div>One question that we are asked is "Do you need to remove the masking before drying?" In general the Polyethylene or paper masking is not a very good moisture barrier, so it should not hinder drying very much. There is generally more risk of damage to the sheet if the masking is removed prior to drying, so unless you have good handling conditions to prevent damage, the marginal improvement in drying time is usually not worth the risk.</div><div><br /></div><div>Once the sheet has been dried, it should either be used immediately or stored in a dehumidified area with a dew point less than 10F. To illustrate why this is the case, on a hot, humid day a dried sheet can absorb 0.5% water within 3 to 4 hours and at this level, bubbles could occur during processing.</div>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-8819582871786610305.post-47622716531439062202012-02-06T10:47:00.009-05:002012-02-06T14:38:24.349-05:00Printing with Polycarbonate<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiL33D8p72K502dDJOGGIRoOjhMKNVGAr8OIQ8UoUM-VsLOmJWW8kYpGVa5H2xt0V-YsdPe3m-0SFpJGjPbrt0FWcQxRITm1C21ZtbaDGoRG3Y5oYCLHo_hyrlV4I-X8Nxnz-YHu01-Fps/s1600/PC+Printing.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="float:right; margin:0 0 10px 10px;cursor:pointer; cursor:hand;width: 320px; height: 157px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiL33D8p72K502dDJOGGIRoOjhMKNVGAr8OIQ8UoUM-VsLOmJWW8kYpGVa5H2xt0V-YsdPe3m-0SFpJGjPbrt0FWcQxRITm1C21ZtbaDGoRG3Y5oYCLHo_hyrlV4I-X8Nxnz-YHu01-Fps/s320/PC+Printing.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5706053429818987954" /></a><br /><iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.blogger.com/video.g?token=AD6v5dwDKXiz4m3lxACiC5SKm8bnJYvWe1zth-ySW8cv9cu9D8R5C6D99Rp59_BK0f9-cDBjQ40igO6_J-ali0wC' class='b-hbp-video b-uploaded' frameborder='0'></iframe><div><br /></div><div>We recently came across a very interesting Blog post by a company called ProtoParadigm. They can be found at <a href="http://protoparadigm.com/">http://protoparadigm.com</a> We encourage you to check them out.</div><div>The blog post covers a topic that we have not seen before - 3D Printing with Polycarbonate. This technique can be used to construct proto-types from Polycarbonate. The profiles in the photo and video were made by printing with Polycarbonate. With the permission of ProtoParadigm, we have included a video and picture from their blog as well as the text below. Please watch the video, it is an amazing use of technology. Their article also clearly identifies the importance of drying Polycarbonate. As users of Polycarbonate sheet know, Polycarbonate absorbs a lot of moisture and should be dried before thermoforming otherwise a lot of bubbles can form in the finished part.</div><div><br /></div><div>Here is their post:</div><div><br /></div><div><span class="Apple-style-span" style="color: rgb(114, 118, 122); line-height: 19px; font-family:arial, sans-serif;font-size:13px;">"We tracked down a number of material samples from our supplier and a little gem called Polycarbonate (PC) caught our eye. Having seen the success of <a href="http://richrap.blogspot.com/2011/09/indestructamendel-polycarbonate-3d.html" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">Richrap</a> printing with Polycarbonate we were anxious to work with it. Polycarbonate (<a href="http://en.wikipedia.org/wiki/Polycarbonate" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">wiki</a>) is a strong thermoplastic with high optical clarity and (relatively) high melting temperature. Unlike PLA with a fast transition temperature, PC slowly softens when heated allowing successful (if not slow) extrusion at lower than processing temperatures. This is useful when switching from a plastic with a lower extrusion temperature as you can slowly start pushing PC through at the temperature of your previous plastic until you clear the hotend. It is important to purge ALL of the previous plastic before raising the printing temperature as ABS puts off some dreadfully nasty fumes at 260C.</span></div><div><span class="Apple-style-span" style="color: rgb(114, 118, 122); line-height: 19px; font-family:arial, sans-serif;font-size:13px;"><br /></span></div><div><span class="Apple-style-span" style="color: rgb(114, 118, 122); line-height: 19px; font-family:arial, sans-serif;font-size:13px;"></span><span class="Apple-style-span" style="color: rgb(114, 118, 122); line-height: 19px; font-family:arial, sans-serif;font-size:13px;">The sample we received was extruded to 1/8″ diameter and we had let it sit out in open air for a good while before getting to it. Initial purging at 260C (Modified Makergear Stepstruder) showed extrudate that was bubbly and white; a big red flag that this plastic needed to be dried. 10 hours at 160F in an old food dehydrator showed filament that was noticeably clearer and extruded a smooth clear thread from the nozzle. Setting extruder to 260C and the <a title="Polyimide Tape" href="https://www.protoparadigm.com/products-page/polyimide-tape/" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">Polyimide Tape</a> covered heated bed to 120C we repurposed an ABS printing profile for PC and started printing; once flow-rate was dialed in we tried printing our <a href="http://www.thingiverse.com/thing:10261" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">Plastic T-Slot</a>. It was by far the strongest beam we had printed and clear enough that looking straight through it you could make out objects on the other side.</span></div><div><span class="Apple-style-span" style="color: rgb(114, 118, 122); line-height: 19px; font-family:arial, sans-serif;font-size:13px;"><br /></span></div><div><span class="Apple-style-span" style="color: rgb(114, 118, 122); line-height: 19px; font-family:arial, sans-serif;font-size:13px;"></span><span class="Apple-style-span" style="color: rgb(114, 118, 122); line-height: 19px; font-family:arial, sans-serif;font-size:13px;">It’s worth noting that adjusting temperature is similar to PLA, printing at higher flow-rates will require higher extruder temperatures for a consistent melt. An indication the flow-rate is to high or temperature to low is stripping or skipping at the filament driver. Those with Bowden style extruders will need to watch for signs of excessive force where the Bowden tube meets the filament driver and hotend. For the Ultimaker I’m using <a href="http://www.thingiverse.com/thing:10799" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">this thing</a> to keep everything secure. If you print PC near the high end of your firmwares temperature limit, PID fluctuations can send it hot enough to force a shutdown of the hotend; temperatures drop, nozzles clog, filaments strip, things get ugly. Also, for hotends that use PTFE (teflon) insulators there is the concern of dangerous fumes when temperatures approach 300C (see <a href="http://en.wikipedia.org/wiki/Polymer_fume_fever" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">Polymer Fume Fever</a> for example.) Care should be taken to avoid inhalation of dangerous fumes or, better yet, to avoid creating them.</span><span class="Apple-style-span" style="color: rgb(114, 118, 122); line-height: 19px; font-family:arial, sans-serif;font-size:13px;"><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background- background-position: initial initial; background-repeat: initial initial; font-size:13px;color:transparent;">", it’s finally time to share what we’ve learned about printing with Polycarbonate. As we recently announced, pre-orders for Polycarbonate in both 3mm and 1.75mm diameters are available. It took us awhile to get the details sorted out, but we’ set for a ship date of January 30, 2012. There’s a whole world of materials out there for that hungry printer on your desk, and we plan to dish up a feast.</p></span><span class="Apple-style-span" style="color: rgb(114, 118, 122); line-height: 19px; font-family:arial, sans-serif;font-size:13px;"><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; background-position: initial initial; background-repeat: initial initial; ">Larger prints were prone to peeling off the print-bed if they contained too many long aligned traces; examining the datasheet revealed that this PC had a mold release additive, great for injection molding, not so great for us (the PC available for pre-order does NOT have this additive and should stick easier to print beds). Small objects printed fine with no warping but we needed to find a way to keep large prints held down; enter <a title="ABS Glue: Weld, Cast, Texture and More!" href="https://www.protoparadigm.com/2011/12/abs-glue-weld-cast-texture-and-more/" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">ABS Glue</a>. Painting a thin coat of that on the bed before printing completely eliminated peeling and warping, we could even print <em style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; background-position: initial initial; background-repeat: initial initial; ">without</em> the heated bed and maybe see only the smallest of curling on the corners of large prints.</p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; background-position: initial initial; background-repeat: initial initial; ">To test the effect that leaving the PC out in open air was having we split up the sample; one went in the dehydrator, another into one lucky fellow’s home for a couple days. Printing with them revealed obvious difference. The dried sample printing clear and smooth without hiccups, the sample that had gone through a few days of home living printed white and would occasionally pop and bubble. Comparing prints side by side shows an obvious reduction in clarity and surface quality for the undried filament. While we haven’t done any numerical testing of compared strength, the moisture laden sample felt more brittle and prints made from it break much easier. Objects printed with the dried PC are clear and strong. Returning to the T-Slot it is clear to see the differences between dry filament and filament left where humidity is not controlled. Click the pictures below for high resolution to really see the differences.</p></span><span class="Apple-style-span" style="color: rgb(114, 118, 122); line-height: 19px; font-family:arial, sans-serif;font-size:13px;"><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; background-position: initial initial; background-repeat: initial initial; ">All in all, a very simple material to start printing with. As long as it is kept relatively free of moisture and/or dried, printed objects turn out looking good, are well bonded and very strong. This is a plastic that can take a bit more of a beating and stand a little more heat, not bad if you need something close to you’re hotend such as a cooling duct. Printing parameters we’re using so far are:</p><h3 style="margin-top: 0px; margin-right: 0px; margin-bottom: 24px; margin-left: 0px; padding-top: 15px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 16px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; font: normal normal normal 16px/20px Arial, sans-serif; text-transform: none; color: rgb(0, 0, 0); background-position: initial initial; background-repeat: initial initial; ">Makerbot</h3><ul style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; list-style-type: none; list-style-position: initial; list-style-image: initial; background-position: initial initial; background-repeat: initial initial; "><li style="margin-top: 0px; margin-right: 0px; margin-bottom: 5px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: middle; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; list-style-image: url(https://www.protoparadigm.com/wp-content/themes/mazine/images/bullet.png); list-style-type: initial; list-style-position: inside; background-position: initial initial; background-repeat: initial initial; ">Extruder – Makergear Plastruder (modified directing heat closer to nozzle and further away from insulator)</li><li style="margin-top: 0px; margin-right: 0px; margin-bottom: 5px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: middle; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; list-style-image: url(https://www.protoparadigm.com/wp-content/themes/mazine/images/bullet.png); list-style-type: initial; list-style-position: inside; background-position: initial initial; background-repeat: initial initial; ">Extrusion Temperature – 260C (success at low and high flow rates)</li><li style="margin-top: 0px; margin-right: 0px; margin-bottom: 5px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: middle; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; list-style-image: url(https://www.protoparadigm.com/wp-content/themes/mazine/images/bullet.png); list-style-type: initial; list-style-position: inside; background-position: initial initial; background-repeat: initial initial; ">Bed – Heated Polyimide Tape (aka Kapton) bed at 120C OR unheated bed with <a title="ABS Glue: Weld, Cast, Texture and More!" href="https://www.protoparadigm.com/2011/12/abs-glue-weld-cast-texture-and-more/" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">ABS Glue</a> brushed down before hand</li></ul><h3 style="margin-top: 0px; margin-right: 0px; margin-bottom: 24px; margin-left: 0px; padding-top: 15px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 16px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; font: normal normal normal 16px/20px Arial, sans-serif; text-transform: none; color: rgb(0, 0, 0); background-position: initial initial; background-repeat: initial initial; ">Ultimaker</h3><ul style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; list-style-type: none; list-style-position: initial; list-style-image: initial; background-position: initial initial; background-repeat: initial initial; "><li style="margin-top: 0px; margin-right: 0px; margin-bottom: 5px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: middle; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; list-style-image: url(https://www.protoparadigm.com/wp-content/themes/mazine/images/bullet.png); list-style-type: initial; list-style-position: inside; background-position: initial initial; background-repeat: initial initial; ">Stock Extruder</li><li style="margin-top: 0px; margin-right: 0px; margin-bottom: 5px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: middle; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; list-style-image: url(https://www.protoparadigm.com/wp-content/themes/mazine/images/bullet.png); list-style-type: initial; list-style-position: inside; background-position: initial initial; background-repeat: initial initial; ">Extrusion Temperature – 270C (evaluating how to safely go hotter for better inter-layer adhesion)</li><li style="margin-top: 0px; margin-right: 0px; margin-bottom: 5px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: middle; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; list-style-image: url(https://www.protoparadigm.com/wp-content/themes/mazine/images/bullet.png); list-style-type: initial; list-style-position: inside; background-position: initial initial; background-repeat: initial initial; ">Bed – Unheated BlueTape or Polyimide Tape (recommended for keeping parts flat) bed with <a title="ABS Glue: Weld, Cast, Texture and More!" href="https://www.protoparadigm.com/2011/12/abs-glue-weld-cast-texture-and-more/" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">ABS Glue</a>brushed down before hand</li><li style="margin-top: 0px; margin-right: 0px; margin-bottom: 5px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: middle; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; list-style-image: url(https://www.protoparadigm.com/wp-content/themes/mazine/images/bullet.png); list-style-type: initial; list-style-position: inside; background-position: initial initial; background-repeat: initial initial; ">Add-on <a href="http://www.thingiverse.com/thing:10799" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">Ultimate BowdenFeeder Repair Kit</a> to keep Bowden assembly secure</li></ul><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 18px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; background-position: initial initial; background-repeat: initial initial; "> </p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 9px !important; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: 0px; outline-style: initial; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; background-position: initial initial; background-repeat: initial initial; ">We’ve got it on pre-order, prices include shipping within the USA, world wide shipping is available through our<a title="International Ordering" href="https://www.protoparadigm.com/contact/international-ordering/" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">international ordering form</a> with an additional $9.00 to match the increased shipping cost of the flat rate mailers we are able to use. We have a scheduled ship date of January 30, 2012 after which the product can batch with other orders and the shipping cost will be subtracted back out of the product listing if we have any remaining inventory. Go on over and grab some in either <a title="Polycarbonate Half Pound (0.5lb) Coil 3mm Filament Pre-Order" href="https://www.protoparadigm.com/products-page/3mm-filament/polycarbonate-1lb-coil-3mm-filament/" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">3mm</a> or <a title="Polycarbonate Half Pound (0.5lb) Coil 1.75mm Filament Pre-Order" href="https://www.protoparadigm.com/products-page/1-75mm-filament/polycarbonate-half-pound-0-5-lb-coil-1-75mm-filament/" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; outline-width: initial; outline-style: none; outline-color: initial; font-size: 13px; vertical-align: baseline; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: transparent; color: rgb(31, 34, 38); text-decoration: none; cursor: pointer; background-position: initial initial; background-repeat: initial initial; ">1.75mm</a>."</p></span></div>Unknownnoreply@blogger.com1tag:blogger.com,1999:blog-8819582871786610305.post-87688728597125018892012-01-10T09:33:00.006-05:002012-01-10T10:02:24.158-05:00How thick does Transparent Armor need to be?<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4kLG7OuTQTv3Qzx4LlIXl53KO0m56fHpv62hYhvPnc9Y21aC8XR4iDVFCqiAwFuym5WROG4BGUtTpIFO5zbrx4WKIMTZwf6WON_dmvWXzXfR-uAEij9Baphvy4CA5O0S353EAQPOPLZs/s1600/Fotolia_29384149_M.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 214px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4kLG7OuTQTv3Qzx4LlIXl53KO0m56fHpv62hYhvPnc9Y21aC8XR4iDVFCqiAwFuym5WROG4BGUtTpIFO5zbrx4WKIMTZwf6WON_dmvWXzXfR-uAEij9Baphvy4CA5O0S353EAQPOPLZs/s320/Fotolia_29384149_M.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5696012024200801106" /></a>A question that we are frequently asked is how thick is transparent armor made from glass and polycarbonate?<div>The answer to the question depends on what level of threat the armor needs to stop. As we discussed in a recent post, the Kinetic energy of a bullet can be calculated if the weight of the bullet and the speed of the bullet are known using the following formula:</div><div><br /></div><div>Kinetic Energy (Joules) = 1/2 x Mass of bullet (grams) x [Velocity of bullet (m/s)]^2</div><div><br /></div><div>The more Kinetic Energy the bullet has, the thicker and heavier the transparent armor needs to be. Of course there are many manufacturers of bullet resistant glass and transparent armor. Each of these manufacturers have their own knowledge of how to produce the lightest and thinest armor to stop a specific threat. However, if we look at the top military transparent armor producers, there is only limited variation in the performance of the products.</div><div><br /></div><div>We recently compared data published on the internet from the top laminators to see how thick and how heavy their products are to stop a given threat. We compared products that were designed to stop rounds with between 650 Joules and 3500 Joules of Energy. Many of the manufacturers do not publish the data for rounds with Energy above 3500 Joules as much of the information is classified.</div><div><br /></div><div>Within the energy range considered there was surprisingly little variation in the thickness and weight of products. We analyzed the data and carried out some linear regression and were able to obtain the following equations:</div><div><br /></div><div>Thickness (mm) = [0.0085 x Energy (Joules)] + 10</div><div><br /></div><div>Weight (kg/m^2) = [0.02 x Energy (Joules)] +20</div><div><br /></div><div><br /></div><div>Using these equations we can calculate that to stop a bullet weighing 9.45 g and traveling at 830 m/s the energy would be about 3255 Joules.</div><div>This would give a thickness of about 38 mm and a weight of about 85 kg/m2.</div><div><br /></div><div>Of course, just making some transparent armor of this thickness and weight does not guarantee that it will stop this level of threat. The armor has to be properly designed and tested by a certified testing company. The figures do show what the main manufacturers are able to achieve.</div><div>It should also be remembered that the Kinetic Energy is not the only factor that needs to be considered - other factors such as the shape of the bullet need to be taken into account.</div><div><br /></div><div>The above figures are based upon transparent armor solutions using Glass and Polycarbonate. A more expensive option is to use advanced materials in the construction such as transparent ceramics. The performance of these ceramics, while not available in detail, is discussed on some of the manufacturers websites and claims of 20% weight reduction and 10% thickness reduction are listed. </div>Unknownnoreply@blogger.com2tag:blogger.com,1999:blog-8819582871786610305.post-15803419699726653622011-11-15T10:39:00.011-05:002011-11-15T13:16:17.816-05:00Birefringence, Photoelasticity, Anisotropic Materials, Iridescence and the Rainbow Effect - Part 3<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaXQXcrhvQMma4laN1h25-Re4Dbs8t0wiVFbMqCp2azGeI0Bm9_QxNJ8sLK0oYTf15dXwH2TiLPqmIHtKn9TwbwTAbuFpYNp6fnUDvajphI2a8R_B4Kd2e8I3M_FtozbFEtp5c9sYZct0/s1600/Fotolia_12818072_XS.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 285px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaXQXcrhvQMma4laN1h25-Re4Dbs8t0wiVFbMqCp2azGeI0Bm9_QxNJ8sLK0oYTf15dXwH2TiLPqmIHtKn9TwbwTAbuFpYNp6fnUDvajphI2a8R_B4Kd2e8I3M_FtozbFEtp5c9sYZct0/s320/Fotolia_12818072_XS.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5675248048085182258" /></a>In the final blog post of this trilogy we will discuss Iridescence and how it can cause a rainbow effect on abrasion resistant coated Polycarbonate sheet. We will also discuss how the rainbow effect can be minimized.<div>Iridescence is the rainbow or oil slick type pattern that often appears on the surface of a Polycarbonate sheet particularly under artificial lighting conditions.</div><div><br /></div><div>Coated Polycarbonate sheet has a thin film of coating on the surface of the sheet in order to protect the sheet against abrasion damage. It is this thin film of coating material that causes the problem, in much the same way that a thin film of oil on the surface of a pool of water exhibits the rainbow patterns. The effect is due to the process known as interference. </div><div><br /></div><div>As discussed in previous blog posts, whenever light travels from a material with one refractive index to another material with a different refractive index, some of the light is reflected. In the case of the coated Polycarbonate sheet, when light moves from the air into the coating some of the light is reflected. Then, when the light moves from the coating into the actual Polycarbonate, some more of the light is reflected. When the light that is reflected from the first surface comes into contact with the light that is reflected from the second surface the light waves recombine. </div><div><br /></div><div>Depending on how thick the coating layer is, the light waves may be in sync when they recombine or may be out of sync when they recombine. If they are in sync the two waves will added together and will have constructive interference. If they are out of sync the two waves will start to cancel each other out and will have destructive interference. </div><div><br /></div><div>Since visible light has wavelengths of 380nm(violet) to 750nm (red) and a typical hard coat has a thickness of 4 to 7 microns [4000 to 7000 nm], the coating thickness is an order of magnitude thicker than the wavelengths of visible light. A small percentage variation in the coating thickness can therefore change whether the constructive interference or destructive interference occurs. If there is variation of coating thickness over a small area of sheet, even if the variation is only tens or hundreds of nanometers, then there will be areas of constructive interference and areas of destructive interference. This variation in the interference patterns is part of the cause of the iridescence or rainbow effect.</div><div><br /></div><div>The question then becomes, how do we eliminate the variation in coating thickness? Abrasion resistant coatings are often added to sheet by a process known as flow coating. The sheet is hung vertically and coating solution is allowed to run down the surface of the sheet from top to bottom under gravity. The solvents are then allowed to evaporate. If the sheet is allowed to move before most of the solvents have evaporated, the coating surface can become uneven. However, we need to remember that the coating surface is not the only surface that we need to be concerned about - there is also the sheet surface that is reflecting light. The sheet is extruded between large chrome rolls which are powered by motors. If there is any variation in the motor speed of these motors or the motors pulling the sheet, there can be variation in the thickness of the sheet. While the variation in the thickness will be small, it only requires very small variation to cause iridescence.</div><div><br /></div><div>The reality is that neither the sheet producers or the abrasion resistant coaters have the ability to control their processes to the level of 10-100nm thickness. If we look at sheet producers, many of them state that their thickness specification is plus or minus 10%. On a 0.118" thick sheet that corresponds to 300,000 nanometers. While this is an overall thickness tolerance and not a measure of local variation of thickness, it does give some idea of the magnitude of the problem. Using this information we can determine that the sheet producers and coaters cannot prevent the problem. In many cases sheet producers often blame the coaters for the problem and coaters often blame the sheet producers. This then leaves us with the question of how do we solve the problem?</div><div><br /></div><div>To answer the question we will briefly move to another topic - different types of lights. Traditional incandescent light bulbs have a relatively smooth light spectrum across the visible region and are similar to sunlight in this respect. When sunlight is split into its component wavelengths (such as in a rainbow) there is a smooth transition from violet through the various colors to red. There are no wavelengths missing. An incandescent light bulb behaves in the same way (as do some full spectrum LED bulbs). </div><div>Fluorescent bulbs, mercury bulbs, sodium bulbs and non full spectrum LEDs are different. When the light is split into its component parts, there are peaks at some wavelengths and gaps at other wavelengths. For example, a low sodium bulb emits an almost monochromatic light source at 589.3nm and a standard fluorescent bulb has 22 peaks with the main four being Mercury at 437nm, Terbium at 543nm, Mercury at 547nm and Europium at 611nm. These wavelengths of a fluorescent bulb combine to yield a light that looks like natural light but has discrete wavelengths rather than the continual spectrum of natural light.</div><div><br /></div><div>Having a light source composed of discrete wavelengths rather than a continuous spectrum is a major problem for iridescence; when the light is reflected from the two surfaces the discrete wavelengths make the problem much larger as there are no intermediate colors to cancel out the iridescent effect. In short, the light source can make the problem of iridescence much greater.</div><div><br /></div><div>The best way to reduce the effect of iridescence is to change the lighting source to a full spectrum light source such as incandescent bulbs or full spectrum LEDs. If the only option is to use fluorescent bulbs, it is better to use a bulb with more emission peaks to more closely resemble full spectrum light.</div><div><br /></div><div>Another option to completely resolve the problem is to use what is known as an index matched abrasion resistant coating. The Polycarbonate sheet has a refractive index of 1.585 and most coatings have a refractive index of 1.49. If an abrasion resistant coating with a refractive index of 1.585 is used, the light will treat the coated Polycarbonate sheet as a single layer material and the effect of iridescence will be completely eliminated. While this process sounds great (and HighLine Polycarbonate can offer index matched abrasion resistant coated products) there is a significant downside - index matched coatings are very expensive. In most applications it is better to install full spectrum bulbs to reduce the problem.</div><div><br /></div><div>Finally, to illustrate the effect of lighting on the visual appearance of iridescence we will recount a case study about the problem. A rail car manufacturer was experiencing oil slick like patterns on the Polycarbonate windows of their railcars. The manufacturer of the windows was inspecting the windows prior to sending them to the rail car manufacturer to try and identify the problem. They were unable to detect the issue as their factory was lit with incandescent lights. When the windows were installed in the railcars, the oil slick appearance was easily visible because the internal lights on the rail car were fluorescent bulbs.</div><div>The most practical solution would have been to change the bulb type on the railcar, but unfortunately the window manufacturer did not understand the problem. They told the rail car manufacturer that the problem was due to birefringence, which, as anyone who has read these three blog posts knows, was not the cause of the problem. By understanding the cause of the problem it is easier to recommend a solution to the customer.</div><div><br /></div><div><br /></div>Unknownnoreply@blogger.com1tag:blogger.com,1999:blog-8819582871786610305.post-85719056488697197522011-11-10T12:13:00.005-05:002011-11-10T12:53:04.811-05:00Birefringence, Photoelasticity, Anisotropic Materials, Iridescence and the Rainbow Effect - Part 2<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBr8bzioxeiO9q1RvirnGtr9Vrou2azIe7d-vvNW_BsnwkTgrMGjXmeXXgVkefGIVs21zmGYVcazkzhpnijVyupfarGLrXbe7YhTXlm1lHYjNigy-2M8M_CieswVV7ALOUMXp8soZfMZk/s1600/IMG_0008.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 240px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBr8bzioxeiO9q1RvirnGtr9Vrou2azIe7d-vvNW_BsnwkTgrMGjXmeXXgVkefGIVs21zmGYVcazkzhpnijVyupfarGLrXbe7YhTXlm1lHYjNigy-2M8M_CieswVV7ALOUMXp8soZfMZk/s320/IMG_0008.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5673416861197998674" /></a>In the last post we discussed how stresses in Polycarbonate can cause the material to become Anisotropic and exhibit Birefringent properties. Light waves parallel to the stress direction will travel through the sheet at a different speed than the light waves perpendicular to the stress direction.<div><br /></div><div>It is possible to visualize the stresses in the sheet due to the birefringent properties of the sheet. A technique known as Photoelasticity is often used. In this method light is first passed through a polarizing filter, in order to block all components of the light not vibrating in the direction of the plane. The light coming through the filter is then known as polarized light. The light is then allowed to pass through the Polycarbonate part being examined. The birefringent properties caused by the stresses cause the polarized light to be split into two perpendicular components each moving at different speeds which are governed by the amount of stress in each direction. The components of the light waves recombine on leaving the Polycarbonate. When this light is then viewed through a second polarizing filter it is possible to see the effect of the retardation of the light in the form of "rainbow" like patterns. There is a lot of theory that can be explored on the method of Photoelasticity and this theory can easily be researched by carrying out a web search. In this blog we do not plan to go into advanced theory of how the light waves recombine, but rather discuss how the method of Photoelasticity can be practically used.</div><div><br /></div><div>In the picture at the top of this blog post is a photograph taken of a piece of Polycarbonate with a hole drilled through it. The photograph was taken with a simple phone camera and two polarizing filters bought from a camera shop for $25 each. One filter was put behind the Polycarbonate part and one filter was put in front of the part. Although this cheap set up does not compare with advanced equipment for visualizing and measuring Photoelasticity, it does provide a simple practical tool for visualizing stresses in Polycarbonate parts.</div><div><br /></div><div>In the Photo it can be seen that there are high levels of stresses on each side of the hole. We suspect that these stresses were caused by poor drilling technique using the wrong drill bit for Polycarbonate and operated at the wrong speed. It is also possible that the drill was started while in contact with the sheet. The technique of Photoelasticity allows us to visualize these stresses and therefore allows us to adjust fabricating methods to minimize stresses. This information is particularly important as we know that areas of increased stress are prone to cracking and damage, especially when exposed to certain solvents. </div><div><br /></div><div>We invite readers who are involved in fabricating Polycarbonate parts to try this test method themselves to see the stress areas on the parts. All you need to do is buy two Polarizing filters from a camera shop.</div><div><br /></div><div>In this section of the trilogy of blog posts on the subject of the rainbow effect, we have seen how stresses in Polycarbonate sheet can lead to birefringence and that these stresses can be visualized through polarizing filters as a rainbow type pattern. </div><div>However, it should be understood that rainbow effect seen on some hard coated Polycarbonate sheet without the use of polarizing filters is not due to the birefringence of the material. These rainbow type patterns on hard coated sheet are often very easy to see with just the eye and can cause the visual appearance of the sheet to seem very poor. In the last post on this topic, we will discuss what causes the rainbow effect on coated sheet and how its effect can be minimized.</div>Unknownnoreply@blogger.com1tag:blogger.com,1999:blog-8819582871786610305.post-33000533140221184522011-10-23T12:56:00.011-04:002011-10-27T09:24:20.533-04:00Birefringence, Photoelasticity, Anisotropic Materials, Iridescence and the Rainbow Effect - Part 1<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7NfXJMmHHWMH5M-4mRejEirTlj6oFwRpvL7HqymRte9xx2mvPAgSExsjWvMJ8X2Au1imluI5ywUFnW5beFFzWOdCXEiteJezwxEy0wh4YZ2flWmtZV4Cm9m3qn_ZxA8gSVpbb_Y-vycc/s1600/rainbow.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 240px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7NfXJMmHHWMH5M-4mRejEirTlj6oFwRpvL7HqymRte9xx2mvPAgSExsjWvMJ8X2Au1imluI5ywUFnW5beFFzWOdCXEiteJezwxEy0wh4YZ2flWmtZV4Cm9m3qn_ZxA8gSVpbb_Y-vycc/s320/rainbow.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5666734657308215138" /></a>One question that we are often asked about Polycarbonate is what causes the rainbow like patterns on coated sheet and how can they be eliminated. <div>The answer is not simple and we will need to answer the question over two or three posts. There is also a lot of confusion in the industry about what causes the effect. Often people try to explain the effect using the wrong terms. </div><div><br /></div><div><b>Birefringence and anisotropic materials</b></div><div>The first term that we will discuss is Birefringence or the double refraction of light when it passes through an Anisotropic material. At this stage, don't worry too much about these terms, we will explain them as we go. Birefringence is often the term that is incorrectly used to explain the rainbow patterns seen on the surface of some coated Polycarbonate sheet. As we will explain, Birefringence can allow us to see stresses in the sheet using polarizing filters - they allow us to see the stresses which will appear as rainbow like effects. However, birefringence is not the cause of the rainbow like effect which can be seen with the eye on the surface of hard coated Polycarbonate sheet.</div><div><br /></div><div>To explain birefringence and anisotropic materials we will start with a discussion about the structure of Polycarbonate. Polycarbonate is a long molecule containing Carbon, Hydrogen and Oxygen atoms. A simple web search can give details of the chemical formula. When Polycarbonate is heated and allowed to cool without being subject to any stresses, these molecules will be arranged randomly.</div><div>During the production of extruded sheet, the Polycarbonate is melted and then extruded through a wide die into a sheet format. The sheet is then pulled out of the die by some pull rollers through some chrome polishing rolls to create a smooth surface on the sheet. The pull rolls create some stress in the sheet in the direction of extrusion, but not in the direction perpendicular to the extrusion. The sheet is cooled and allowed to "set" while still being pulled by these rolls. This difference in stress in the sheet between the extrusion direction and the direction perpendicular to extrusion is commonly referred to as shrinkage. We have discussed shrinkage in more detail in previous blog posts; shrinkage is able to be controlled below 1%, although often it is possible to find sheet with high levels of shrinkage of 10% or more.</div><div><br /></div><div>The stresses in the Polycarbonate can be eliminate by annealing the sheet - heating it above its glass transition temperature and then allowing it to cool. Also stresses can often be added to the sheet by some fabrication methods.</div><div><br /></div><div>The more shrinkage that the Polycarbonate sheet has, the more stress it has in the extrusion direction and the more the Polycarbonate molecules are aligned in the extrusion direction. This alignment of the Polycarbonate molecule chains causes the Refractive Index of the Polycarbonate in the direction of the extrusion to be different than the Refractive Index in the direction perpendicular to the extrusion. As explained in previous blog posts, the refractive index is a measure of how fast light travels in a material. The difference of refractive index in the two directions causes extruded Polycarbonate to become what is known as an Anisotropic Material - where the speed of light traveling through the material is dependent upon the direction of the material.</div><div>If a Polycarbonate sheet is produced without any stress or 0% shrinkage, it would not be Anisotropic.</div><div><br /></div><div>The difference in the Refractive Index between the two directions can be calculated using the Stress Optics Law:</div><div><br /></div><div>(RI1 - RI2) = C x (Stress1 - Stress2)</div><div>Where:</div><div>RI1 = Refractive Index in extrusion direction</div><div>RI2 = Refractive Index in direction perpendicular to extrusion</div><div>C = Stress Optic Constant</div><div>Stress1 = Stress in extrusion direction</div><div>Stress2 = Stress in direction perpendicular to extrusion.</div><div><br /></div><div>If the Refractive Index in one direction is different than the Refractive Index in the other direction, the components of the waves of light moving through the Polycarbonate in one direction will travel at a different speed than the light in another direction. The more Polycarbonate that the waves travel through, the more the one wave will lag behind the other. This effect is known as Retardation of the wave.</div><div>The retardation of the wave can be calculated using the following formula:</div><div><br /></div><div>Retardation = C x thickness of Polycarbonate x (Stress1 - Stress2)</div><div><br /></div><div>The amount of retardation of the wave is therefore proportional to both the thickness of the sheet and the differences in the stresses in the two directions. The retardation will be much lower on thin sheet with low shrinkage.</div><div><br /></div><div>When the components of the light in the two directions emerge from the sheet they will recombine. However, how they recombine will be a function of the phase difference caused by the retardation of the light. There could be constructive or destructive recombining of the waves at different wavelengths.</div><div><br /></div><div>In the next post on this subject we will look at how these waves combine. We will also look at how we can use a polarizer to look at the stresses in the sheet using an experimental method known as Photoelasticity.</div><div><br /></div><div><br /></div><div><br /></div><div> </div>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-8819582871786610305.post-7351373624689543112011-07-14T12:13:00.004-04:002011-07-22T13:57:13.303-04:00Bonding Polycarbonate Sheet<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPv4egox6sD5_VJ4CbwnT6aOiF-8tUFGb6L4uv5Ls8Zwa9-vQjzdCsQqQ3awIbj1c8D1ZBAy0oEJlz8709XdOAYiJFWoeZhmaaaFpq7XY1UioLgO04O3K2DKzcsyrKaR4AQEsNGFiBR30/s1600/instrument+cluster.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 213px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPv4egox6sD5_VJ4CbwnT6aOiF-8tUFGb6L4uv5Ls8Zwa9-vQjzdCsQqQ3awIbj1c8D1ZBAy0oEJlz8709XdOAYiJFWoeZhmaaaFpq7XY1UioLgO04O3K2DKzcsyrKaR4AQEsNGFiBR30/s320/instrument+cluster.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5629242636837019042" /></a>One question that we are often asked is how can two Polycarbonate sheets be bonded together?<div><br /></div><div>At HighLine Polycarbonate we are mainly involved in producing Polycarbonate sheets with a wide range of high tech properties. We only engage in a limited amount of fabrication which includes routing of the sheets into finished part shapes.</div><div><br /></div><div>We do not engage in fabrication that requires bonding of two sheets together. Some of our customers do engage in this type of fabrication and we will list some of the methods that we know about for joining two sheets of Polycarbonate together. We would be very interested to hear from our readers about other methods that they know about so that we can update the post with additional information.</div><div><br /></div><div>We do not plan to cover physical methods of joining sheets together such as rivets, screws and tapes.</div><div><br /></div><div>- The first method that we know about is using Methylene Chloride or a 60%/40% mixture of Methylene Chloride and Ethylene DiChloride. This solvent bonding technique is known to give a good bond strength and excellent optical clarity along with low capital investment. The mixture of Methylene Chloride and Ethylene DiChloride gives a slightly longer curing time than neat Methylene Chloride allowing more time to get the parts in the correct position; this is particularly important for larger parts. Suppliers of these chemicals can be found on Google. We recommend reading the Material Safety Data Sheet for information on safe handling and disposal before using any chemicals. We also recommend that you test any method on a small part before using on critical parts.</div><div>Before starting the solvent bonding process, both surfaces should be cleaned with warm water. If there are greasy areas, IsoPropanol (IPA) should be used to wipe the surfaces clean. Some fabricators recommend dissolving between 2% and 5% Polycarbonate saw dust in the Methylene Chloride or Methylene Chloride/Ethylene DiChloride solvents before use in order to give a stronger bond strength. We have yet to see any evidence that the saw dust improves the bond strength. In any case, if you choose to try this method, make sure that all of the saw dust is fully dissolved before use, because otherwise lumps of saw dust may prevent good surface contact between the two parts. Another recommendation that we have heard from fabricators is that in order to prevent whitening of the joint occurring, 10% Glacial Acetic Acid should be added to the solvents. Whitening does not always occur, so we would only recommend that you try this solution if you are having problems with whitening on your particular parts.</div><div>Having made up the solution, the solvent should be applied to one of the clean parts. The two parts should then be clamped together with several hundred psi pressure for about 5 minutes. The parts should then be allowed to cure in a well ventilated area at room temperature for between two and five days.</div><div><br /></div><div><br /></div><div>- The second method is to use an adhesive; this is a cheaper solution than solvent bonding but we believe that the bond strength and the optical clarity are not as good. Many customers have had excellent results with products such as "Weld-on". These products can easily be found using Google.</div><div><br /></div><div>- Other methods such as vibration welding and ultrasonic welding have had varying degrees of success depending on the part shape and thickness. We would suggest that you contact manufacturers of the equipment to see if these options are suitable for your needs. These methods would require capital investment.</div><div><br /></div><div>- The final option that we know about is to laminate the two parts together using an interlayer material such as transparent Polyurethane. This method is often used to manufacturer ballistics laminates where Polycarbonate layers are bonded to glass. This method requires a lot of specialist knowledge and equipment, such as an autoclave so it is unlikely to be viable for the majority of applications.</div><div><br /></div><div>We look forward to hearing about more bonding methods from our readers. </div>Unknownnoreply@blogger.com1tag:blogger.com,1999:blog-8819582871786610305.post-77620985667563533432011-05-25T10:40:00.004-04:002011-05-25T11:10:23.909-04:00FDA and NSF Standard 51 grades and UV absorbers<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9JNXMartbEfIWPxaXToOFvIKYoYFz-w-6zssJurdYWd6GyIxUsmYIX1U5qvlkoVsqWt2N7Y2x-pUp9bklQ5GI6RFJizawla55E9VOytdXEj6yMr6BmKtAkslevMZZnRqxjFeyPa_CbrQ/s1600/j0182882.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 212px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9JNXMartbEfIWPxaXToOFvIKYoYFz-w-6zssJurdYWd6GyIxUsmYIX1U5qvlkoVsqWt2N7Y2x-pUp9bklQ5GI6RFJizawla55E9VOytdXEj6yMr6BmKtAkslevMZZnRqxjFeyPa_CbrQ/s320/j0182882.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5610665259382691314" /></a>Polycarbonate sheet is widely understood to block UV wavelengths below 385-390 nm. What is not so well known is it is not the Polycarbonate that blocks these wavelengths, but rather the UV absorbers that are added to the Polycarbonate that block the UV light.<div>Polycarbonate sheet that has no UV absorbers will only block wavelengths below 290 nm. Unfortunately wavelengths below 385 nm will cause the Polycarbonate to weather and become brittle and yellow. Manufacturers therefore add UV absorbers to the Polycarbonate resin to give it some protection against the UV light. Some outdoor grades of Polycarbonate also have an additional cap layer or coating heavily loaded with additional UV absorbers to further protect the sheet against the affect of UV light.</div><div><br /></div><div>There are some grades of Polycarbonate, that are often known as FDA or NSF Standard 51 compliant grades that have no UV absorbers. The reason that no UV absorbers are added is that these grades are designed to be used in the Food Processing environment and the UV absorbers are not approved by the FDA to be used in Food Processing areas. The manufacturers therefore produce grades without the UV absorbers. Because these FDA grades of Polycarbonate sheet have no UV absorbers, they should not be used outside as they will yellow very quickly.</div><div>One question that we are often asked is are the FDA approved grades safe to be used in food contact applications? The FDA grades of Polycarbonate sheet do not have UV absorbers in them because they are not approved for materials used in Food Processing environments. However, the Polycarbonate itself does still have Bisphenol A or BPA in it and there is currently a great deal of debate about whether BPA is safe in food contact applications such as baby feeding bottles. As a result of this debate, at HighLine Polycarbonate we do not sell any Polycarbonate sheet that will be used in applications where it comes into regular, direct contact with food. However, FDA grades of Polycarbonate sheet can be used as machine guards to protect operators on food packaging lines when the machine guards do not come into contact with food that will be eaten.</div><div><br /></div><div>One un-intended market for FDA approved grades of Polycarbonate sheet is to customers who bond Polycarbonate sheet to other materials using a UV cured adhesive. The adhesive requires light from a UV lamp to pass through the sheet in order to bond it to another material. The UV absorbers in Standard Polycarbonate sheet block the UV light from the lamp preventing the adhesive from curing. By using an FDA grade of Polycarbonate sheet, the adhesive is able to be cured effectively. After bonding, the sheet can be protected against UV light by adding a coating with UV absorbers.</div>Unknownnoreply@blogger.com1tag:blogger.com,1999:blog-8819582871786610305.post-59734414079846823472011-05-09T17:36:00.005-04:002011-05-09T18:33:53.192-04:00Kinetic Energy of Ballistics rounds and transparent armor<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhjh961NkOqYxPSl0-0YluN2LXZ9eeBuX4RK2Fh8UhyphenhyphenunwcZ6zsAMwgdlUvGEOa-Zsv9Eg_O86ryCvMq01e1Jf5LZ9fy5QFwEiVjMvC4C0j1Uq6PulA801PMiz0GzsrBKESzaEf4S4UELw/s1600/MRAP2.bmp" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 213px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhjh961NkOqYxPSl0-0YluN2LXZ9eeBuX4RK2Fh8UhyphenhyphenunwcZ6zsAMwgdlUvGEOa-Zsv9Eg_O86ryCvMq01e1Jf5LZ9fy5QFwEiVjMvC4C0j1Uq6PulA801PMiz0GzsrBKESzaEf4S4UELw/s320/MRAP2.bmp" border="0" alt="" id="BLOGGER_PHOTO_ID_5604833716922696242" /></a>We are often asked about the difference between bullet resistant windows installed in 24hrs stores or banks and the transparent armor used by the military. <div>The bullet resistant windows in convenience stores and banks are often made of cell cast acrylic sheet or a combination of acrylic and Polycarbonate. They are often about 1.25" to 1.375" thick and are designed to protect against threats that are likely to be encountered in that environment. Typical bullet resistant ratings of UL.752 Level 1 to Level 3 are encountered. But what does a UL.752 Level 1, Level 2 or Level 3 mean and how does it compare to the transparent armor of military applications?</div><div><br /></div><div>A UL.752 Level 1 material is designed to stop 9mm FMCJ rounds weighing 8.0 grams traveling at a velocity of up to 394 meters/second.</div><div>A UL.752 Level 2 material is designed to stop 0.357 Magnum JSP rounds weighing 10.2 grams traveling at a velocity of up to 419 meters/second.</div><div>A UL.752 Level 3 material is designed to stop 0.44 Magnum rounds weighing 15.6 grams traveling at a velocity of up to 453 meters/second.</div><div><br /></div><div>But what does this mean? One of the most important factors in determining whether a bullet resistant structure will stop a ballistics round is how much Kinetic Energy does the ballistics round have.</div><div>Using the equation for Kinetic Energy:</div><div>Kinetic Energy (Joules) = 1/2 x Mass (Kilograms) x Velocity (meters/second)^2</div><div><br /></div><div>Calculating the Kinetic Energy for the UL.752 Level 1 ballistics round we find:</div><div><br /></div><div>Kinetic Energy = 1/2 x 0.008 x 394 x 394 = 620 Joules</div><div><br /></div><div>For the three UL.752 Levels we get:</div><div>Level 1<span class="Apple-tab-span" style="white-space:pre"> </span>620 Joules</div><div>Level 2 <span class="Apple-tab-span" style="white-space:pre"> </span>895 Joules</div><div>Level 3<span class="Apple-tab-span" style="white-space:pre"> </span>1600 Joules</div><div><br /></div><div>We can see as the weight and the velocity of the round increase the Kinetic Energy of the round increases. The bullet resistant material needs to be able to resist a larger amount of Kinetic Energy.</div><div><br /></div><div>We can now look at the military grades to compare the amount of Kinetic Energy they are designed to stop. Military grades of transparent armor are composed of multiple layers of glass and polycarbonate. The glass can be of various types. In some cases advanced materials such as Spinel and ALON are also used. Often the structures can be many inches thick.</div><div><br /></div><div>For US military grades a standard known as ATPD.2352 is used. The different rounds that the materials must stop is listed but the velocities are classified. The fact that the velocities are classified makes it difficult to calculate the required Kinetic Energy that must be absorbed; it would be possible to take an educated guess at the velocities, but for the purposes of this blog post, we do not need to do this is we can use the NATO standard AEP55 STANAG 4549 Volume 1.</div><div><br /></div><div>STANAG 4549 has 5 protection levels for Light Armored Vehicles. For the purposes of the discussion on transparent armor we will just look at Levels 1 and 4.</div><div><br /></div><div>Level 1 material is designed to stop a 7.62 mm x 51 NATO ball round weighing 9.65 grams traveling at 833 meters/second.</div><div>Level 4 material is designed to stop a 14.5 mm x 114 API/B32 round weighing 64 grams traveling at 911 meters/second.</div><div><br /></div><div>A Level 1 round has a Kinetic Energy of 3,348 Joules</div><div>A Level 4 round has a Kinetic Energy of 26,557 Joules</div><div><br /></div><div>You can see that the energy that a UL.752 Level 1 material needs to stop is over 40 times less than a STANAG 4549 Level 4 material. The reason for this difference is that the type of ballistics rounds likely to be encountered at a convenience store are likely to be very different from those encountered by the military. Indeed the deterrence factor of bullet resistance glass in commercial applications should not be underestimated.</div><div><br /></div><div>It should be noted that this discussion is very much a simplification and is only meant to compare the Kinetic Energy of the different rounds used for the different tests. There are a number of parameters that have not been discussed in this blog post such as the multi shot spacing and the shape of the round. </div>Unknownnoreply@blogger.com3tag:blogger.com,1999:blog-8819582871786610305.post-87993697449312450522011-02-13T13:43:00.015-05:002011-02-14T12:05:38.762-05:00Variable Message Signs (VMS) and Polycarbonate<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBCazALSsn6_0FMBkCSR2pOpdK3rZuHl4LSXpl1eUfvaeS-iE3HZO1iC4RTcgEAznS2NJzszsIiUipbF3wgPgQjUFsX6yHaBK5r-xttWqhiN7e-12QkmM7vcJnvJp5uNKNGM6zcUT8U_s/s1600/VMS.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 240px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBCazALSsn6_0FMBkCSR2pOpdK3rZuHl4LSXpl1eUfvaeS-iE3HZO1iC4RTcgEAznS2NJzszsIiUipbF3wgPgQjUFsX6yHaBK5r-xttWqhiN7e-12QkmM7vcJnvJp5uNKNGM6zcUT8U_s/s320/VMS.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5573247574024834594" /></a><br /><!--StartFragment--> <p class="MsoNormal">Over recent months we have had a large number of customer contact us regarding Variable Message Signs (VMS), also known as Dynamic Message Signs (DMS), and the use of Polycarbonate for these signs.<span style="mso-spacerun: yes"> </span>These signs are often used as traffic signs to warn drivers or give special information.</p> <p class="MsoNormal"><br /></p><p class="MsoNormal"><br /></p><p class="MsoNormal"><br /></p><p class="MsoNormal">The signs often consist of a bank of either yellow or red LEDs behind a protective Polycarbonate front shield.<span style="mso-spacerun:yes"> </span>The Polycarbonate is used to protect the sign against impact damage and environmental conditions.</p> <p class="MsoNormal">Most of the questions that we get asked relate to a technical standard such as the European Standard EN.12966 for VMS.<span style="mso-spacerun: yes"> </span>The main concern relates to the test, which simulates reflection of sunlight when the sun is at a low angle in the sky (5 or 10 degrees).<span style="mso-spacerun: yes"> </span>In this situation, the sun is reflected off the Polycarbonate shield to the driver and partially obscures the light coming from the LEDs, making the sign difficult to read.</p> <p class="MsoNormal"> The sign can be made easier to read by either reducing the reflection of the sunlight or increasing the amount of LED light transmitted through the sheet – either by increasing the LED brightness or increasing the light transmission of the Polycarbonate sheet.</p> <p class="MsoNormal">The test apparatus used for EN.12966 is shown in the picture accompanying this blog post [Please click on the picture to enlarge].<span style="mso-spacerun: yes"> </span>The principal of reducing reflection and increasing transmission is the same as that discussed in our previous blog posts with the exception that we are not concerned with the entire visible spectrum.<span style="mso-spacerun:yes"> </span>We are specifically concerned with how the Polycarbonate interacts with the Yellow LEDS (wavelength 635 nm) and the Red LEDs (wavelength 590-595 nm) for the vast majority of VMS.</p> <p class="MsoNormal">The problem that most VMS manufacturers have experienced is that they frequently buy general purpose Polycarbonate sheet, that has not been optimized for VMS, from distributors or manufacturers that are not aware of the options available.<span style="mso-spacerun: yes"> </span>Much of this material has been produced with the idea of minimizing the production cost; as a result there is often large amounts of second grade (regrind) material in the product.<span style="mso-spacerun: yes"> </span>As discussed in our previous blog posts, this regrind has the effect of lowering the transmission across the visible spectrum and in particular in the yellow region of the spectrum used by the yellow LEDs of VMS.</p> <p class="MsoNormal">The first method improving the visibility of VMS signs in low sunlight is therefore to use an optical grade of Polycarbonate that has been design for VMS use, such as grades offered by HighLine Polycarbonate.<span style="mso-spacerun: yes"> </span>The next method is to reduce the reflection and increase the transmission by the use of specially designed coatings.<span style="mso-spacerun: yes"> </span>The added advantage of these coatings is that they improve the UV and weather resistant performance of the Polycarbonate, preventing the material from yellowing over time, which would also reduce the transmission in the yellow part of the spectrum.<span style="mso-spacerun: yes"> </span>The coatings also add scratch resistance to the sheet, which is important in a road traffic environment.</p> <p class="MsoNormal">The following table shows the effect of using a high quality VMS Polycarbonate and using an anti-reflective hard coat.<span style="mso-spacerun: yes"> </span>The sheet used is 3mm / 0.118” thick.</p><p class="MsoNormal"><b>Yellow LED Transmission</b><span style="mso-tab-count:1"> </span></p><p class="MsoNormal"><span style="mso-tab-count:1"></span><span style="mso-tab-count:1"></span>Uncoated GP Polycarbonate (*) 83.8%<span style="mso-tab-count:1"> </span></p><p class="MsoNormal"><span style="mso-tab-count:1"></span><span style="mso-tab-count:1"></span><span style="mso-tab-count:1"></span>Uncoated VMS Polycarbonate<span class="Apple-tab-span" style="white-space:pre"> </span>89.0%<span style="mso-tab-count:1"> </span></p><p class="MsoNormal"><span style="mso-tab-count:1"></span>VMS Polycarbonate with anti-reflective hard coat 91.0%<span style="mso-tab-count:1"> </span></p><p class="MsoNormal">VMS Polycarbonate with anti-reflective hard coat outside and optical coating inside 93.6%</p><p class="MsoNormal"><br /></p> <p class="MsoNormal"><b>Red LED Transmission</b><span style="mso-tab-count:1"> </span></p><p class="MsoNormal"><span style="mso-tab-count:1"></span><span style="mso-tab-count:1"></span>Uncoated GP Polycarbonate (*) 86.0%<span style="mso-tab-count:1"> </span></p><p class="MsoNormal"><span style="mso-tab-count:1"></span><span style="mso-tab-count:1"></span><span style="mso-tab-count:1"></span>Uncoated VMS Polycarbonate 89.7%<span style="mso-tab-count:1"> </span></p><p class="MsoNormal"><span style="mso-tab-count:1"></span><span style="mso-tab-count:1"></span><span style="mso-tab-count:1"></span>VMS Polycarbonate with anti-reflective hard coat 92.0%</p><p class="MsoNormal">VMS Polycarbonate with anti-reflective hard coat outside and optical coating inside 95.5%</p><p class="MsoNormal">[* the GP Polycarbonate was purchased from a distributor and was produced by a major manufacturer as their standard product].</p> <p class="MsoNormal">For Yellow LEDs it is therefore possible to increase the transmission by 8.6% [91.0/83.8 = 8.6% increase] by using a properly designed Polycarbonate with an anti-reflective hard coat, for Red LEDs the increase is 7.0% [92.0/86.0 = 7.0% increase].</p> <p class="MsoNormal">For both color LEDs the anti-reflective hard coat is also able to reduce the reflection by 25%.</p> <p class="MsoNormal">The combination of the increase in transmission and the reduction in reflection significantly increases the readability of the signs in sunlight.</p> <p class="MsoNormal">A further option to improve the performance is to use an advanced optical anti-reflective on the inside surface.<span style="mso-spacerun: yes"> </span>The use of the advanced optical coatings is not recommended for the outside surface, as they are not suited to use in a dusty and dirty roadside environment.<span style="mso-spacerun:yes"> </span>By using these materials on the inside surface the transmission for yellow LEDs rises to 93.6% and the transmission for red LEDs rises to 95.5%.</p> <p class="MsoNormal">These figures give an increase in transmission of 11.6% for yellow LEDs and 11.0% for Red LEDs.<span style="mso-spacerun: yes"> </span>They also reduce the reflection by 56%.<span style="mso-spacerun:yes"> </span>One question that has not yet been completely answered is whether the additional cost of an optical grade anti-reflective is justified by the performance advantage over an anti-reflective hard coat.</p> <p class="MsoNormal"> The other option for VMS is to use an anti-glare hard coat.<span style="mso-spacerun: yes"> </span>At the moment we are investigating the performance of these materials in this application.<span style="mso-spacerun: yes"> </span>Anti-glare materials are different from anti-reflective materials in that they scatter the light to reduce reflection; so while you can reduce reflection you also significantly lower the transmission and the clarity of the sign.<span style="mso-spacerun: yes"> </span>It remains to be determined whether the loss in transmission is acceptable.<span style="mso-spacerun: yes"> </span>At the moment we are very reluctant to recommend anti-glare coatings for VMS applications even though we are able to provide anti-glare coatings.</p><p class="MsoNormal">To summarize, for VMS signs it is important to use a Polycarbonate sheet that has been designed for VMS applications rather than use general purpose Polycarbonate sheet. With an anti-reflective hard coat the transmission can be increased 7.0% for red LEDs and 8.5% for yellow LEDs and the reflection can also be reduced 25%. </p> <!--EndFragment-->Unknownnoreply@blogger.com1tag:blogger.com,1999:blog-8819582871786610305.post-72066968787181371752010-09-23T11:16:00.004-04:002010-09-23T11:31:20.506-04:00Sheet - conversion between weight and area<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDTJHYJ6W8VPbWAYiw-LQz7RQn0grhrBodss6oxNAXI7h4lSUaUJhoUO2abRDaSt4UCR40MJ26oIN0REaEN-Z2lMZX5LLkaYGHkrwpdmGYBFT4eX10vaPuRxolxkNgc9_0Rvr9d-djwS4/s1600/j0308887.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 210px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDTJHYJ6W8VPbWAYiw-LQz7RQn0grhrBodss6oxNAXI7h4lSUaUJhoUO2abRDaSt4UCR40MJ26oIN0REaEN-Z2lMZX5LLkaYGHkrwpdmGYBFT4eX10vaPuRxolxkNgc9_0Rvr9d-djwS4/s320/j0308887.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5520129215234528738" /></a>A short time ago we wrote a blog post about determining how an increase in resin price would affect the sheet price. The calculation involved converting a $ per pound price into a $ per square foot price.<div>To assist Polycarbonate (and other Polymer) sheet users with this calculation, we have put a simple spreadsheet on our<a href="http://highlinepc.com/Files/tabid/853/Default.aspx"> website</a>. This spreadsheet is available to be downloaded and shared. We just ask users not to remove the logo or the disclaimer.</div><div><br /></div><div><br /></div><div>The spreadsheet includes three simple calculations:</div><div><br /></div><div>1) Given the dimensions of a sheet it allows the user to calculate the sheet weight.</div><div>2) Given the dimensions of a sheet and the price in $/lb, it allows the user to calculate the price in $/sqft.</div><div>3) Given the dimensions of a sheet and the price in $/sqft, it allows the user to calculate the price in $/lb.</div><div><br /></div><div>We hope that the spreadsheet is useful and we intend to keep it updated with any feedback and comments that we receive.</div><div><br /></div>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-8819582871786610305.post-49171626772998789702010-09-14T12:42:00.004-04:002010-09-14T12:52:54.691-04:00Self-repairing coating videoMany people have asked us about our self-repairing coating, but it is only when they have seen it in action that they become really excited. We have therefore put together a short video clip so that you can see how well this coating works.<br /><br />Please click on the link below to view the video.<br /><br /><a href="http://highlinepc.com/News/tabid/400/Default.aspx"><span style="font-weight:bold;">watch video</span></a><br /><br /><br /><br />If you need more information about this coating, please contact us at info@highlinepc.comUnknownnoreply@blogger.com0tag:blogger.com,1999:blog-8819582871786610305.post-956877514480615262010-08-17T11:37:00.009-04:002010-08-17T16:52:27.516-04:00Polycarbonate and the Power of the Brand nameIn this blog post we have moved away from our normal technical content to discuss a subject that has some major implications for the Polycarbonate sheet market place. The question that we will address is: Are powerful brand names still as important as they once were in the plastic sheet market?<br /><br />There is no doubt that in the past brand names such as Lexan for Polycarbonate and Plexiglas for Acrylic dominated the market. These products were often specified in to projects and could command a premium price from customers due to actual or perceived quality. We decided to look and see if customers were still referring to the brand names or were just looking for Polycarbonate.<br />As the web is one of the primary means that customers use to find out information about a product, we decided to look at the search interest for "Polycarbonate" and "Lexan" in the United States. In the first graph, we can see that the search interest for Polycarbonate has remained relatively constant since 2004 with some minor decrease due to the economy. <br /><br /><script type="text/javascript" src="http://www.gmodules.com/ig/ifr?url=http%3A%2F%2Fwww.google.com%2Fig%2Fmodules%2Fgoogle_insightsforsearch_interestovertime_searchterms.xml&up__property=empty&up__search_terms=polycarbonate&up__location=US&up__category=0&up__time_range=empty&up__compare_to_category=false&synd=open&w=320&h=350&lang=en-US&title=Google+Insights+for+Search&border=%23ffffff%7C3px%2C1px+solid+%23999999&output=js"></script><br /><br />In the second graph we can see that the search interest for Lexan has dropped off significantly and steadily since 2004. As there is still a good interest in Polycarbonate it is possible to conclude that customers are using the generic term Polycarbonate in searches while moving away from the brand name Lexan. Now this information does not mean that Lexan sales have decreased, customers searching for Polycarbonate may still buy Lexan products. However, it does suggest that the brand name value maybe decreasing and if this is the case, the price premium may also be decreasing.<br /><br />There are of course many events that have happened over time that may explain this trend. During the period being examined, GE Plastics sold the Lexan Polycarbonate part of the operations to SABIC. This transfer of Lexan from a traditional American company to a Saudi Arabian company could certainly affect the branding strategy and the search interest of the brand.<br /><br /><script type="text/javascript" src="http://www.gmodules.com/ig/ifr?url=http%3A%2F%2Fwww.google.com%2Fig%2Fmodules%2Fgoogle_insightsforsearch_interestovertime_searchterms.xml&up__property=empty&up__search_terms=lexan&up__location=US&up__category=0&up__time_range=empty&up__compare_to_category=false&synd=open&w=320&h=350&lang=en-US&title=Google+Insights+for+Search&border=%23ffffff%7C3px%2C1px+solid+%23999999&output=js"></script><br /><br />To see if the affect of the brand importance was confined to Lexan, we also decided to look at the other powerhouse brand in the US clear sheet market - Plexiglas. In the graph below we can see how the Plexiglas name has also decreased in search importance. Of course it can be argued that the transfer of the brand from the respected US company Rohm and Haas to a less well known French company Arkema is similar to the situation at Lexan, at least in the US market shown in the graph,<br /><br /><script type="text/javascript" src="http://www.gmodules.com/ig/ifr?url=http%3A%2F%2Fwww.google.com%2Fig%2Fmodules%2Fgoogle_insightsforsearch_interestovertime_searchterms.xml&up__property=empty&up__search_terms=plexiglas&up__location=US&up__category=0&up__time_range=empty&up__compare_to_category=false&synd=open&w=320&h=350&lang=en-US&title=Google+Insights+for+Search&border=%23ffffff%7C3px%2C1px+solid+%23999999&output=js"></script><br /><br />The results of search importance for both Lexan and Plexiglas lead us to question whether brand is as important as it once was in the US clear sheet market. Having questioned this point, there is still no doubt that these names are still valuable branding tools both now and for the foreseeable future. Now that customers, using the internet, are able to evaluate the alternative options more efficiently, the brand name may not be the dominant factor in the purchasing decision.<br />We would be interested to hear your comments on whether you think brand names are still as important in the plastics industry as they once were and if not, what are the implications?<br /><br />Lexan is a brand name of SABIC Basic Industries Corp. Plexiglas is a brand name of Arkema Inc.Unknownnoreply@blogger.com3tag:blogger.com,1999:blog-8819582871786610305.post-30253040314073592272010-08-01T10:26:00.016-04:002010-08-02T09:48:54.158-04:00The Quality of Polycarbonate and Light Transmission<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNA87_Gm0IyXcQc_gwrdHqbmGyDRji_EVLy270C79qCJTxXkqUKPdDjmydbtipjLOx2Jz4mUS7QiNHufZ01ATjbahkB3Y0KJiQaszbJaGHfQSaGTSP89K3uJTVtsoHG-vD6mzosi0GuVI/s1600/Internal+loss+of+light+transmission.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 135px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNA87_Gm0IyXcQc_gwrdHqbmGyDRji_EVLy270C79qCJTxXkqUKPdDjmydbtipjLOx2Jz4mUS7QiNHufZ01ATjbahkB3Y0KJiQaszbJaGHfQSaGTSP89K3uJTVtsoHG-vD6mzosi0GuVI/s320/Internal+loss+of+light+transmission.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5500456057084504530" /></a><span class="Apple-style-span" style="font-size:small;">As we explained in a previous blog post, we would typically expect the light transmission of 0.118" one side hard-coated Polycarbonate to be in the range of 90% [with 5.1% reflectance on the uncoated side, 4% reflectance on the coated side and a little internal loss of light transmission due to the internal structure of the Polycarbonate itself]. As the thickness of the Polycarbonate increases, we would expect the internal loss of light transmission to also increase a little.</span><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;"><br /></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;">We were recently asked by a customer to apply an anti-reflective coating to the uncoated side of 0.236" one side hard-coated Polycarbonate. The Polycarbonate was provided by the customer and had been produced by another manufacturer. By applying the anti-reflective coating we were expecting to reduce the reflection on the uncoated side from 5.1% to around 1.0%. We were therefore expecting to increase the overall light transmission from 89-90% to around 94%.</span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;"><br /></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;">After we had coated the material with the anti-reflective we discovered, to our surprise, that we were only getting a light transmission of 89%. The application of the anti-reflective coating appeared to have failed. We examined our coating process and found no obvious problems. We then decided to test the light transmission of the material before we applied the anti-reflective coating. To our surprise we found that the light transmission was only 84-85% instead of the 90% that we expected. The problem was with the quality of the competitors Polycarbonate and not the anti-reflective coating.</span></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;"><br /></span></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;">We then measured the reflection on both surfaces and calculated the internal loss of light transmission across the entire visible spectrum. We then repeated this process with our own 0.236" Polycarbonate. We then plotted our the internal loss of light transmission for both materials over the visible spectrum. This plot can be seen in the diagram at the top of the page (for a better view, click on the picture).</span></span></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;"><br /></span></span></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;">The results were shocking. </span></span></span></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;">Over the range of 450-500 nm, our material had an internal loss of light transmission of 2% and the competitors had a loss of 5%</span></span></span></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;">Over the range of 525-575 nm, our material had an internal loss of light transmission of 4% and the competitors had a loss of 7%</span></span></span></span></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;">Over the range of 650- 750 nm our material had an internal loss of light transmission of 1% and the competitors had a loss of 7%</span></span></span></span></span></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;"><br /></span></span></span></span></span></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;">The end result was that the customer would have been better off buying our HighLine Polycarbonate without an anti-reflective rather than applying an expensive anti-reflective to the competitors material. In the end the customer decided to use our Polycarbonate with an anti-reflective and achieved a light transmission of over 94%.</span></span></span></span></span></span></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;"><br /></span></span></span></span></span></span></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;">The lesson to be learned from this recent experience is that not all Polycarbonate sheet is equal. The Polycarbonate sheet from this competitor, who is a major international supplier of Polycarbonate sheet, clearly had a much lower light transmission across the visible spectrum than the Polycarbonate sheet from HighLine Polycarbonate. This lower transmission is caused by inferior resin, use of regrind and the commodity production methods used by some of the large producers. In the vast majority of applications, particularly commodity applications, this loss of light transmission is not important. However, in some quality and high-tech applications, a 6% light transmission loss in the 650-750nm range can be critical. Any application requiring an anti-reflective coating should seriously consider the quality of the base Polycarbonate and should be extremely cautious about buying an off the shelf product from a distributor. Polycarbonate sheet for high quality applications should always be bought directly from the manufacturer so that you can have the material produced specifically for the required application.</span></span></span></span></span></span></span></span></div><div><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="color:#000000;"><span class="Apple-style-span" style="font-size:small;">All of HighLine Polycarbonate's material is designed for high quality optical applications. If you are using another supplier's material it would be wise to ask for them to provide the light transmission curve for the actual lot number of the sheet you will be receiving. We were certainly surprised by the poor quality of some of the material that is being sold as high quality product.</span></span></span></span></span></span></span></span></div><div><div><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUn8F1EeV1DtsOnR4h_A63cSXkWFENpfn5NAEeLLUOOTKMwSTMUHJwEWsHLR1v7tJktKgnh50qfsG5uV2hdzzRDe0o-gxLr7A0meKBq_JOUtaqosOY7V_OIa-_s_B1mr-M0wHTtZ1qrAo/s1600/Internal+loss+of+light+transmission.jpg"></a><span><span></span></span></div></div>Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-8819582871786610305.post-14013251782688754562010-07-13T10:34:00.006-04:002011-03-06T11:34:15.666-05:00Bullet Resistant Laminates and Transparent Armor<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjg_uiUWF88hZPja_haETdECq70QYaB_48dk5ZZg-5ICroaXzjwK8Q6yXr5ykn1aTkCGXQ97QG3n4bVmgghLmptMxGB2MekzX1kxjgJT9sUQ0vwX7OLgmjRM3XaDAxIFyg_K7F65YbIh1k/s1600/MRAP2.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 213px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjg_uiUWF88hZPja_haETdECq70QYaB_48dk5ZZg-5ICroaXzjwK8Q6yXr5ykn1aTkCGXQ97QG3n4bVmgghLmptMxGB2MekzX1kxjgJT9sUQ0vwX7OLgmjRM3XaDAxIFyg_K7F65YbIh1k/s320/MRAP2.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5493399220572728242" /></a><p class="MsoNormal">One statement that we often hear is that Polycarbonate is “bullet-proof”.<span style="mso-spacerun: yes"> </span>There are two problems with this statement; the first is that a single Polycarbonate sheet by itself should not be used to stop bullets as it really offers very little protection.<span style="mso-spacerun: yes"> </span>The second problem is subtle, materials constructed from Polycarbonate are not bullet-proof but rather bullet-resistant; fire enough shots of high enough caliber and velocity and they will eventually fail.</p> <p class="MsoNormal">There has been a need in both the civilian and military sectors to develop glazing materials with bullet-resistance.<span style="mso-spacerun: yes"> </span>There are a number of ways of achieving this bullet resistance depending on the required stopping power, cost and weight restrictions.<span style="mso-spacerun: yes"> </span>While this article cannot cover all of the options in detail, we will try to give an overview of the options:</p> <p class="MsoNormal"> <o:p></o:p></p> <p class="MsoNormal" style="margin-left:.5in;text-indent:-.25in;mso-list:l0 level1 lfo1;tab-stops:list .5in">1)<span style="font:7.0pt "Times New Roman""> </span>Perhaps the easiest to make and the cheapest product to buy is specially designed Acrylic sheet that has been specifically tested for bullet resistance.<span style="mso-spacerun: yes"> </span>Typically a 1.25” thick Acrylic sheet such as Plexiglas SBAR will stop a 9mm bullet as tested by UL.752 Level 1 test.<span style="mso-spacerun: yes"> </span>To get increased stopping power, it is necessary to increase the thickness to 1.375”.<span style="mso-spacerun: yes"> </span>At this thickness Plexiglas SBAR product will stop a 0.357” shell as tested by UL.752 Level 2 test.<span style="mso-spacerun: yes"> </span>The limitation of this technology is the thickness required to achieve greater stopping power becomes difficult to produce and difficult to install due to the size and the weight.</p> <p class="MsoNormal"> <o:p></o:p></p> <p class="MsoNormal" style="margin-left:.5in;text-indent:-.25in;mso-list:l0 level1 lfo1;tab-stops:list .5in">2)<span style="font:7.0pt "Times New Roman""> </span>The next option is to use a combination of Acrylic and Polycarbonate.<span style="mso-spacerun: yes"> </span>This method is used by Sheffield Plastics, amongst others, in their Hygard BR range.<span style="mso-spacerun: yes"> </span>The Acrylic and Polycarbonate are laminated together in various configurations in a vacuum chamber using an interlayer to bond the sheets together.<span style="mso-spacerun:yes"> </span>The 9mm UL.752 Level 1 protection is achieved by laminating a ½” acrylic sheet between two layers of 1/8” Polycarbonate.<span style="mso-spacerun: yes"> </span>The acrylic sheet absorbs the energy while the more flexible Polycarbonate holds the structure together and prevents shards of Acrylic breaking off and injuring the person behind the window.<span style="mso-spacerun: yes"> </span>It can be seen that this type of structure is only 0.75” thick to achieve the Level 1 protection compared to 1.25” for the SBAR product.<span style="mso-spacerun: yes"> </span>The 0.357 Level 2 protection is achieved by sandwiching two 3/8” Acrylic sheets between two outer 1/8” Polycarbonate sheets giving a total thickness of 1.0”.<span style="mso-spacerun: yes"> </span>A UL.752 Level 3 protection, which uses a Magnum 0.44” has a similar construction that is 1.25” thick.<span style="mso-spacerun: yes"> </span>These multiple layer plastic constructions offer greater protection from a thinner material, but at the downside of a greater cost.</p> <p class="MsoNormal"> <o:p></o:p></p> <p class="MsoNormal" style="margin-left:.5in;text-indent:-.25in;mso-list:l0 level1 lfo1;tab-stops:list .5in">3)<span style="font:7.0pt "Times New Roman""> </span>The next option is to introduce glass.<span style="mso-spacerun: yes"> </span>Different companies use different options for the configuration, but nearly all of them use glass bonded to Polycarbonate using inter-layers.<span style="mso-spacerun: yes"> </span>Typically one or two sheets of 1/8” Polycarbonate are used.<span style="mso-spacerun: yes"> </span>The glass absorbs the energy of the ballistics material and the Polycarbonate holds the material together.<span style="mso-spacerun: yes"> </span>Often a sheet of Polycarbonate is put on the inside surface to act as a “spall” layer.<span style="mso-spacerun:yes"> </span>This layer prevents shards of glass breaking off and injuring the person behind the glass.<span style="mso-spacerun: yes"> </span>This type of option is often used in armoring commercial automobiles for VIPs or diplomats.<span style="mso-spacerun: yes"> </span>Using the glass gives additional stopping power, but at the expense of cost and additional weight.</p> <p class="MsoNormal"> <o:p></o:p></p> <p class="MsoNormal" style="margin-left:.5in;text-indent:-.25in;mso-list:l0 level1 lfo1;tab-stops:list .5in">4)<span style="font:7.0pt "Times New Roman""> </span>The next option moves from the area of commercial ballistics laminates to military transparent armor.<span style="mso-spacerun: yes"> </span>These laminates often use multiple layers of glass and multiple layers of Polycarbonate – both as spall shields and internal structures.<span style="mso-spacerun: yes"> </span>The completed laminates are often many inches thick and can stop a wide range of military projectiles.<span style="mso-spacerun: yes"> </span>Often several different types of glass can be used in a single window to give different properties, the hardness of the glass and the energy absorption of the glass are two such properties.<span style="mso-spacerun: yes"> </span>Many of the configurations used by different companies are confidential.<span style="mso-spacerun: yes"> </span>The performance of these materials is excellent but they are costly and extremely heavy.</p> <p class="MsoNormal"> <o:p></o:p></p> <p class="MsoNormal" style="margin-left:.5in;text-indent:-.25in;mso-list:l0 level1 lfo1;tab-stops:list .5in">5)<span style="font:7.0pt "Times New Roman""> </span>The final option is to use advanced materials for the construction of the transparent armor.<span style="mso-spacerun: yes"> </span>These materials include ALON, Sapphire and Spinel.<span style="mso-spacerun: yes"> </span>Details of these materials can be found on the websites of their manufacturers.<span style="mso-spacerun: yes"> </span>While these materials offer exceptional protection they are extremely expensive and often the production process can only produce small parts.</p> <p class="MsoNormal"> <o:p></o:p></p> <p class="MsoNormal">At HighLine Polycarbonate we have a great deal of experience in transparent armor.<span style="mso-spacerun: yes"> </span>We have developed a Polycarbonate grade that gives increased performance and stopping power in military laminates compared to other commercial grades of Polycarbonate.<span style="mso-spacerun: yes"> </span>We have also developed an advanced thermoplastic sheet, which is more flexible than Polycarbonate and gives a significant improvement in performance when used as a spall shield.<span style="mso-spacerun: yes"> </span>The material is lighter than Polycarbonate and is resistant to a wide range of chemicals and solvents, making it ideally suited to use in military transparent armor.</p> <p class="MsoNormal"> <o:p></o:p></p> <p class="MsoNormal">At HighLine Polycarbonate we also are able to include EMI/RFI shielding meshes, transparent conductive heaters, self-repairing coatings, anti-fog coatings, super abrasion resistant coatings, IR shielding and anti-microbial properties – all of which enable our products to be used in the harshest of military environments.</p> <!--EndFragment-->Unknownnoreply@blogger.com2tag:blogger.com,1999:blog-8819582871786610305.post-73192800467245491862010-06-29T11:27:00.002-04:002010-06-29T11:32:09.331-04:00Machine Guards and Chemical Resistance<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxlIU5M7c0afU06sblReKs8PmE5j9ZB-YVwv-D2Jv3kPpBsCQ9cfN5YIWbhjsufpVhozTuaLg3msbgKInYJn7nonM-m9h7ql1xcXHzWzMEL8LvCpqWfZZ6KjBeiumEx06XlNqtVc1Mu6A/s1600/j0309621.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 228px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxlIU5M7c0afU06sblReKs8PmE5j9ZB-YVwv-D2Jv3kPpBsCQ9cfN5YIWbhjsufpVhozTuaLg3msbgKInYJn7nonM-m9h7ql1xcXHzWzMEL8LvCpqWfZZ6KjBeiumEx06XlNqtVc1Mu6A/s320/j0309621.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5488218651550525618" /></a><p class="MsoNormal">Polycarbonate has traditionally been used to produce machine guards due to its virtually unbreakable properties.<span style="mso-spacerun:yes"> </span>Its good optical properties, ability to form to shapes and its reasonable cost make it an almost perfect choice for the application.</p> <p class="MsoNormal">One problem with Polycarbonate in some machine guard applications is that some cleaning chemicals, oils, fuels and greases can attack the surface of the sheet over time.<span style="mso-spacerun:yes"> </span>While this chemical attack does not occur in all applications, it can be a severe problem in some industries.<span style="mso-spacerun: yes"> </span>This attack of the sheet means that the guards need to be replaced frequently or the user will have to live with optically and sometimes structurally damaged machine guards.<span style="mso-spacerun: yes"> </span>Coating the Polycarbonate can offer some degree of protection against chemical attack, but this is not the ideal solution as any scratches that occur in the coating provide sites for attack.<span style="mso-spacerun: yes"> </span>Also, using a coating can be a problem if the guards need to be formed, as standard hard-coats will crack.<span style="mso-spacerun: yes"> </span>Another problem with Polycarbonate is that over time the surface can become scratched.</p> <p class="MsoNormal">Even though Polycarbonate is reasonably inexpensive, the cost of replacing a damaged machine guard can be expensive particularly once the cost of machining, forming, installing the guard and machine downtime is taken into account.</p> <p class="MsoNormal">At HighLine Polycarbonate we have developed a new monolithic sheet product known as Grade 5500.<span style="mso-spacerun: yes"> </span>This product has been developed especially for applications requiring exceptional chemical resistance.<span style="mso-spacerun: yes"> </span>The sheet will not be damaged at all by the vast majority of cleaning chemicals, oils, fuels and greases.<span style="mso-spacerun: yes"> </span>The sheet is also much more resistant to scratches than uncoated Polycarbonate, is virtually unbreakable and is lighter than Polycarbonate.<span style="mso-spacerun: yes"> </span>The material has also been approved for contact with foodstuffs having an alcohol content of less than 8% according to the FDA specification 21CFR 177.1500 (11).</p> <p class="MsoNormal">All of these properties make it the ideal replacement for Polycarbonate sheet in machine guard applications, even in the food processing industry, where Polycarbonate is becoming damaged and needs to be replaced.</p> <p class="MsoNormal">For more information about Grade 5500 sheet, contact HighLine Polycarbonate LLC.</p> <!--EndFragment-->Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-8819582871786610305.post-21745908994327967802010-06-04T11:41:00.001-04:002010-06-04T11:44:16.205-04:00Polycarbonate and chemical resistance<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg52dgMVk3ZsEfCK_pTY3HEC6463aL6D-EXqd0r9GUFYZr7KiTNgqanKyxiLkl50Mvx23p68ojnmDk_9tN-4pAoEYCU-ddsERJNnl9u694PI39fTs1sizBXl7l4yqHhHIkZIqRGOu7WTs4/s1600/j0182882.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 212px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg52dgMVk3ZsEfCK_pTY3HEC6463aL6D-EXqd0r9GUFYZr7KiTNgqanKyxiLkl50Mvx23p68ojnmDk_9tN-4pAoEYCU-ddsERJNnl9u694PI39fTs1sizBXl7l4yqHhHIkZIqRGOu7WTs4/s320/j0182882.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5478944629211414354" /></a><p class="MsoNormal">When discussing Polycarbonate, the question of chemical resistance often comes up, particularly in high-tech applications.<span style="mso-spacerun: yes"> </span>Polycarbonate can come into contact with chemicals in a number of ways – cleaning solvents are frequently used in medical applications and machine guards on food processing lines, solvents are also used in printing ink packages in advanced sensors and displays, rail car windows and bus shelters often need cleaning to remove not only dirt but graffiti. </p> <p class="MsoNormal">While chemical resistance is important, it can be a weakness of Polycarbonate with some chemicals and some applications.<span style="mso-spacerun: yes"> </span>The level to which a chemical attacks Polycarbonate depends on a number of factors, the type of chemical (acid, polar solvent, non-polar solvent), the temperature, the contact time and the stress that the Polycarbonate part is under.<span style="mso-spacerun: yes"> </span>Because of the number of factors influencing the effect of a chemical on a Polycarbonate part, the information in supplier data sheets is very general in nature and often has little real world relevance.<span style="mso-spacerun:yes"> </span>There is also very little standardization on suppliers data sheets regarding the chemicals reported and the test methods used to quantify chemical resistance.</p> <p class="MsoNormal">In broad terms there are some chemicals that very aggressively attack Polycarbonate.<span style="mso-spacerun: yes"> </span>These chemicals include Toluene, Benzene, Acetone and Ammonia to name a few.<span style="mso-spacerun: yes"> </span>One interesting experiment to see the effect of these chemicals is to dip a small piece of Polycarbonate into some Acetone.<span style="mso-spacerun: yes"> </span>Nothing visually appears to happen, but the surface does become plasticized.<span style="mso-spacerun: yes"> </span>If the Polycarbonate is then washed in water, the water provides nucleating sites causing the surface to “crystallize”.<span style="mso-spacerun: yes"> </span>The result is that the entire surface instantly turns white.</p> <p class="MsoNormal">Other chemicals such as Isopropyl Alcohol and Ethanol have very little effect on the surface of the Polycarbonate.<span style="mso-spacerun: yes"> </span>We even recommend that our anti-reflective coatings be sprayed with a 70% Isopropyl Alcohol solution to remove fingerprints.<span style="mso-spacerun: yes"> </span></p> <p class="MsoNormal">One method of protecting Polycarbonate sheet from chemical attack is to apply a standard hard-coat to the sheet.<span style="mso-spacerun:yes"> </span>This hard-coat provides a protective barrier.<span style="mso-spacerun: yes"> </span>However, the hard-coat will not protect against all chemicals and if there is a minor scratch in the hard-coat, chemicals can still attack at that point.<span style="mso-spacerun: yes"> </span>It should also be remembered that any edges or drill holes may provide points for chemical attack, so often it is necessary to coat the part after fabrication rather than coat the sheet before fabrication.<span style="mso-spacerun: yes"> </span>There are also some advanced coatings design to protect the sheet against specific chemicals.</p> <p class="MsoNormal">It is important to discuss the application with the Polycarbonate manufacturer to see if chemical attack will be a problem and whether a coating can provide a solution.<span style="mso-spacerun: yes"> </span>At HighLine Polycarbonate we also have some more advanced solutions involving different resin matrices that can protect against solvents in very demanding applications.</p> <!--EndFragment-->Unknownnoreply@blogger.com0tag:blogger.com,1999:blog-8819582871786610305.post-1785438855258101122010-05-14T13:39:00.004-04:002010-05-14T13:44:04.528-04:00Anti graffiti coated Polycarbonate<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiv1BxZBNdBacGGalh8wgSO8VV3K9E0mzqxC0WilNORXsWgEsoVlT7ys86rhm27C6byw8YzqYHrB1m5IwqRZh8b8rj3mgwPsXGDn8bjCQUf2cWainsOOacmVznaLM_65RMs0WKHN9kajMc/s1600/fp063006-22.jpg"><img style="float:right; margin:0 0 10px 10px;cursor:pointer; cursor:hand;width: 320px; height: 214px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiv1BxZBNdBacGGalh8wgSO8VV3K9E0mzqxC0WilNORXsWgEsoVlT7ys86rhm27C6byw8YzqYHrB1m5IwqRZh8b8rj3mgwPsXGDn8bjCQUf2cWainsOOacmVznaLM_65RMs0WKHN9kajMc/s320/fp063006-22.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5471182499803219858" /></a><p class="MsoNormal">Polycarbonate is virtually unbreakable and this property makes it especially suited to environments where the risk of damage by vandalism is high.<span style="mso-spacerun: yes"> </span>These applications include bus shelters, rail car and bus windows, vending machines, advertising and security glazing.<span style="mso-spacerun: yes"> </span>However, vandalism comes in many forms, not just breakage.<span style="mso-spacerun:yes"> </span>Often vandalism consists of graffiti from marker pens and spray paint.<span style="mso-spacerun: yes"> </span>Normally when Polycarbonate is damaged by graffiti the entire Polycarbonate part needs to be replaced.</p> <p class="MsoNormal">A better solution is to apply an anti-graffiti coating, which can be added to either uncoated or a hard-coated sheet.<span style="mso-spacerun: yes"> </span>This type of coating creates a hydrophobic layer that repels water and reduces the wettability of organic solvents.<span style="mso-spacerun: yes"> </span></p> <p class="MsoNormal">When a marker pen is used to write on Polycarbonate with an anti-graffiti coating the inks bead up and do not stick to the sheet; the residue can then be easily wiped of with a soft cloth.<span style="mso-spacerun: yes"> </span></p> <p class="MsoNormal">When spray paint is applied to the anti-graffiti coating, the paint does dry; however, with very little effort the paint can be removed with a very mild abrasive that does not damage the Polycarbonate.<span style="mso-spacerun: yes"> </span>When spray paint is applied to standard Polycarbonate it is virtually impossible to remove the paint.</p> <p class="MsoNormal">Anti-graffiti coated Polycarbonate sheets are more expensive than standard Polycarbonate sheets.<span style="mso-spacerun: yes"> </span>However, they are less expensive than having to buy additional sheet to replace graffiti covered parts.<span style="mso-spacerun: yes"> </span>Often the cost of additional sheet, fabrication of the parts and the expense of removing and reinstalling the parts can be many times the cost of the anti-graffiti coating.</p> <!--EndFragment-->Unknownnoreply@blogger.com1