Lexan
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- For similar products offered by other companies, see polycarbonates.
Lexan (LEXAN) is a registered trademark for General Electric's (now SABIC Innovative Plastics') brand of highly durable polycarbonate resin thermoplastic intended to replace glass where the need for strength 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). Applications are mainly in three domains — building (glazing and domes), industry (machine protection and fabricated parts) and communication and signage.
Discovery
Lexan was discovered in 1953 by GE chemist Dr. Daniel Fox, while working on a wire coating. Dr. Hermann Schnell of Bayer in Germany applied for a U.S. patent on a virtually identical molecule the same year that GE filed for a patent, 1955. Lexan is manufactured by GE Plastics, a unit of General Electric. It is manufactured at several GE plants, the largest being in Mt. Vernon, Indiana; Cartagena, Spain; and Bergen op Zoom, The Netherlands. GE 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 leaches 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.[1] 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."[2]
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 product is the Apple Computer iBook and the iPod; the 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:
- racing cars to replace heavier (and breakable) glass windshields and windows.
- greenhouses for covering.
- the Flexdex skateboards "Clear" models
- for radio-controlled car bodies
- for motorcycle goggles
- Radio-controlled helicopter fins and gyro mounts by RDLohr
- Rubik's cube colored tiles from Cubesmith
- Air hockey pucks
- Hockey rink glass
- 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.[3]
- Nalgene bottles
- Riot shields and the visors of Riot helmets
- The visor in some fencing masks, and in many industrial safety shields and masks.
Lexan in popular culture
- The molecule of Lexan was featured on Star Trek IV: The Voyage Home visually depicted on the Apple Macintosh computer screen, described in the film as "transparent aluminum".[citation needed]
- 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
References
- ^ Potential hazards in food contact applications: see Polycarbonate for details
- ^ http://cerhr.niehs.nih.gov/chemicals/bisphenol/draftBPA_MtgSumm080807.pdf
- ^ http://www.nycsubway.org/cars/r110a.html NYCS R110A description