Lexan

:"For similar products offered by other companies, see polycarbonates."

Lexan (LEXAN) is a registered trademark for SABIC Innovative Plastics' (formerly General Electric Plastics) brand of highly durable polycarbonate resin thermoplastic intended to replace traditional glass and Plexiglas where the need for strength and impact resistance justifies its higher cost. It is a polycarbonate polymer produced by reacting Bisphenol A with carbonyl chloride, also known as phosgene. Lexan is the brand name for polycarbonate sheet in thicknesses from 0.75 mm (0.03 in) to 12 mm (0.48 in) and resin in a wide range of grades. Applications are mainly in three domains — building (glazing and domes), industry (machine protection and fabricated parts) and communication and signage.

Development and patent

GE's discovery of the polycarbonate that is trade named Lexan by chemist Dr. Daniel Fox occurred in 1953, while working on a wire coating, just one week after Dr. Hermann Schnell of Bayer in Germany had independently made the same discovery. Both teams were impressed by the remarkable toughness of the material.

Both companies applied for U.S. patents in 1955. Before it was clear which would win the patent, both agreed that the patent holder would grant a license for an appropriate royalty. [Reminiscences of Kenneth Goldblum, who was involved in the development at GE, [http://www.cems.umn.edu/downloads/alumni/Goldblum.pdf] ] This agreement allowed both companies to concentrate on developing the polymer and was particularly advantageous to GE, since GE would not otherwise have been able to sell a product during the life of the original patent.

Manufacturing

Lexan is now manufactured by SABIC Innovative Plastics. It is manufactured at several SABIC plants, the largest being in Mt. Vernon, Indiana; Burkville, Alabama; Cartagena, Spain; and Bergen op Zoom, The Netherlands. SABIC Innovative Plastics is headquartered in Pittsfield, MA. Jack Welch, former CEO of GE, started as a chemical engineer in this division in Pittsfield.

Properties

Lexan is similar to polymethyl methacrylate (Plexiglas/Lucite/Perspex) and is commonly described as acrylic in appearance, but is far more durable, often to the point of being described as "bulletproof", depending on the thickness of the sample and the type of weapon used.

Lexan may leach bisphenol A, a chemical that some studies linked to cancer. These studies indicate exposure to low levels of BPA causes a range of serious health effects in laboratory animals. [Potential hazards in food contact applications: see Polycarbonate for details] An expert panel of 12 scientists has found that there is "some concern that exposure to the chemical bisphenol A in utero causes neural and behavioral effects," according to the draft report prepared by The National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction. For the general adult population, the expert panel found a "negligible concern for adverse reproductive effects following exposures." [http://cerhr.niehs.nih.gov/chemicals/bisphenol/draftBPA_MtgSumm080807.pdf]

Usage

Lexan is used in the aerospace industry for aircraft canopies, windscreens and other windows, but can be found in household items, such as bottles, compact discs, and DVDs. Perhaps the most visible Lexan consumer products are the Apple iBook and iPod — their gleaming white plastic is Lexan. It also is used by Nalgene for their 1-liter wide mouth water bottle, popular with hikers and mountaineers. Lexan is also used by other water bottle manufacturers.

Lexan is also used in:
* The visors for the helmets on the Apollo space programme
* Automotive headlight covers to prevent small rocks and stones from breaking headlights bulbs
* Racing cars to replace heavier (and breakable) glass windshields and windows
* Greenhouses for covering
* The Flexdex skateboards "Clear" models
* Radio-controlled car bodies
* Motorcycle goggles
* Pseudo-brass knuckles
* Radio-controlled helicopter fins and gyro mounts by RDLohr
* Rubik's cube colored tiles from [http://www.cubesmith.com/ Cubesmith]
* Air hockey pucks
* Hockey rink glass
* Nike Bauer Supreme One90 and Supreme One70 ice hockey skates (specifically, the TUUK Lightspeed 2 blade holders)
* Some guitar picks
* An alternative for brass mouthpieces in brass musical instruments.
* All New York City Subway cars, from R110A to newer cars such as R160B feature Lexan as a defense against vandalism. [http://www.nycsubway.org/cars/r110a.html NYCS R110A description]
* The jars for Blendtec blenders
* Riot shields and the visors of Riot helmets
* The visor in some fencing masks, and in many industrial safety shields and masks
* Cosmic ray detectors as stacks of 1/4 mil sheets
* Doors for Pods in WWE Elimination Chamber
* A surfacing for features in terrain parks at ski and snowboard resorts
* Some spanking paddles

Lexan in popular culture

* Lexan is often used in the TV show "MythBusters" to protect the show's hosts and crew from any explosions.

* Many of the clear containers used in the show "Good Eats" are Lexan containers.

External links

* [http://www.sabic-ip.com/gep/Plastics/en/ProductsAndServices/ProductLine/lexan.html SABIC IP LEXAN]

References