Polycarbonate resins are tough thermoplastics with major markets in the electrical/electronic sectors such as computer and business equipment, optical media, glazing and sheet products and in the automotive industry. Other uses include safety helmets and shields, housing components, household appliances, water cooler bottles, sporting goods, and aircraft and missile components.
The optical media segment which includes CDs and DVDs recorded the strongest growth with rates around 10%/year in the 2001-2005 period. This market saw a peak around 2006-2007 but demand is expected to decline as CDs and recordable CDs are replaced by MP3/MP4 players, high internet bandwidth and USB drives.
First commercial polycarbonate processes were based on bisphenol-A (BPA) which was reacted with phosgene. A number of companies have been developing non-phosgene processes where polymerisation relies on the transesterification of diphenyl carbonate with BPA.
Polycarbonates are long-chain linear polyesters of carbonic acid and dihydric phenols, such as bisphenol-A. Polycarbonate is naturally transparent, and has high strength, toughness, heat resistance, and excellent dimensional and colour stability. It is inherently resistant to combustion, but when burned, it produces an opaque black smoke.