LEDs in Polycarbonate

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.

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.

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.

Is 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.



We will concentrate our discussion to the first two rounds fired, the 0.22LR and the 9mm round.

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.
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.
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.
The 12" x 12" test piece is fully supported and will not move during the testing.

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.

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.

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.

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.

The video even states that their test is completely unscientific.
All of this does not make the video any less interesting or enjoyable. It is also very well produced.

Polycarbonate and the Power of the Brand name

In 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?

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.
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.



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.

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.



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,



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.
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?

Lexan is a brand name of SABIC Basic Industries Corp. Plexiglas is a brand name of Arkema Inc.