||It has been suggested that this article be merged into polycarbonate. (Discuss) Proposed since May 2013.|
Polycarbonate polymer is produced by reacting bisphenol A with phosgene. Lexan is the brand name for polycarbonate sheet and resin in a wide range of grades. Lexan is mainly used in three domains: building (glazing and domes), industry (machine protection and fabricated parts) and communication and signage. Common usages include space and sports helmets, clear high-performance windshields and aircraft canopies, motor vehicle headlight lenses, and bullet-resistant windows.
It is also used in textiles machinery for high-temperature and high-strength polymer application.
Development and patent
Dr. Hermann Schnelle of Bayer in Germany invented the polycarbonate resin in 1953, just one week before chemist Dr. Daniel Fox of GE independently made the same discovery while working on a wire coating. They had created a gooey substance that, once hardened, could not be broken or destroyed without great effort. 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. 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.
In the 1960s, NASA used Lexan-brand polycarbonate for astronaut helmet assemblies and visors which became known as "bubble helmets", including those used by the Apollo moon astronauts. Lexan is also one brand of polycarbonate used to make football and other sports helmets In 1968, Lexan brand polycarbonate sheet could be used in windows, signs, greenhouses and other large applications. By laminating sheets up to 1.25" thick in the 1970s, a material tough enough to stop bullets was created. By 1969, taillights made from Lexan brand polycarbonate were used on the Dino Ferrari. It was also used not only in industrial safety glasses, but also to make lightweight traditional eyewear. Today, it is used in manual fire alarm activation stations, American football helmets, bus shelters, aircraft windows, machine guards, sound walls and ice hockey visors.
Lexan is now manufactured by SABIC Innovative Plastics. It is manufactured at several SABIC plants, the largest being in Mt. Vernon, Indiana and Burkville, Alabama. SABIC Innovative Plastics is headquartered in Pittsfield, Massachusetts. Jack Welch, former CEO of GE, started as a chemical engineer in this division in Pittsfield.
- Reminiscences of Kenneth Goldblum, who was involved in the development at GE, University of Minnesota.
- GE Plastics' "LEXAN Resin Innovation Day" Inspires Imaginative Thinking for New York..., Allbusiness.com, from Business Wire, January 29, 2003.
- Innovation Timeline : Lexan* Resin, SABIC Innovative Plastics.
- Lexan Sheet Applications