Polycarbonate/Bayer

Bayer AG is Europe s leading supplier of ABS, but is some way behind the world s leading producers. In polycarbonates, Bayer is the second largest world producer behind GE Plastics and is ranked fourth largest world polyamide producer. The company has an ambitious expansion strategy for engineering plastics, particularly for polycarbonate, and plans to invest in capacity expansion, especially in the Asia region. 

CD-modified BPA-polycarbonate (CD 2005, Bayer AG). Poly(methyl methacrylate). 

Polycarbonates are an unusual and extremely useful class of polymers. The vast majority of polycarbonates are based on bisphenol A [80-05-7] (BPA) and sold under the trade names Lexan (GE), Makrolon (Bayer), CaUbre (Dow), and Panlite (Idemitsu). BPA polycarbonates [25037-45-0] having glass-transition temperatures in the range of 145—155°C, are widely regarded for optical clarity and exceptional impact resistance and ductiUty at room temperature and below. Other properties, such as modulus, dielectric strength, or tensile strength are comparable to other amorphous thermoplastics at similar temperatures below their respective glass-transition temperatures, T. Whereas below their Ts most amorphous polymers are stiff and britde, polycarbonates retain their ductiUty. 

A reexamination of polycarbonate chemistry was carried out about 50 years after the first aromatic polycarbonates of resorcinol and hydroquinone were discovered. In independent investigations at Bayer AG and General Electric, it was discovered that the polycarbonates of BPA could be prepared (eq. 2). Unlike the ahphatic polycarbonates prepared earlier, which were either hquids or low melting sohds, the aromatic polycarbonates were amorphous sohds having elevated glass-transition temperatures. 

Blends of ABS with polycarbonates have been available for several years (e.g. Bayblend by Bayer and Cycoloy by Borg-Wamer). In many respects these polymers have properties intermediate to the parent plastics materials with heat distortion temperatures up to 130°C. They also show good impact strength, particularly at low temperatures. Self-extinguishing and flame retarding grades have been made available. The materials thus provide possible alternatives to modified poly(phenylene oxides) of the Noryl type described in Chapter 21. (See also sections 16.16 and 20.8.)... 

Today about 75% of the market is held by General Electric and Bayer with their products Lexan and Makrolon respectively. Other manufacturers are ANIC (Italy), Taijin Chemical Co., Mitsubishi Edogawa and Idemitsu Kasei in Japan and, since 1985, Dow (USA) and Policarbonatos do Brasil (Brazil). Whilst this market is dominated by bis-phenol A polycarbonates, recent important developments include alloys with other thermoplastics, polyester carbonates and silicone-polycarbonate block copolymers. 

The TMC polycarbonate homopolymer has a glass transition temperature of 238°C, nearly 100°C above that of the bis-phenol A polycarbonate. Therefore, copolymers will have intermediate glass transitions depending on the relative proportions of TMC and bis-phenol A. Commercial grades (marketed by Bayer as Apec HT) have Vicat softening points from 158 to... 

There is little call for these thermoplastics materials (marketed as Durethan U, Farbenfabriken Bayer) since they are about twice the price of nylons 66 and 6. Where a thermoplastic for light engineering purposes is required with a low water absorption, nylon 11, acetal resins and, in certain instances, polycarbonates are cheaper and, usually, at least as satisfactory. 

Report 42 Polycarbonates, R. Pakull, U. Grigo, D. Freitag, Bayer... 

Bayer MaterialScience (Germany) in the Project "Dream Production" combines part of waste streams of coal-fired power plants, CO2, with the production of polymers. The target is the design and development of a technical process able to produce C02-based polyether polycarbonate polyols on a large scale. The first step was to convert the C02 in new polyols, and these polyols showed similar properties such as products already on the market and can be processed in conventional plans as well (Figure 22). 

In 1953, Farbenfabrican Bayer made linear Polycarbonates. By 1957, they were commercially produced by Bayer and General Electric. These polymers are based on 4, 4 -dihydroxy diphenylpropane (bisphenol A) and phosgene. 

Some of the low-tonnage isocyanates are made without chlorine but this has yet to be proved for MDI and TDI. GE and Bayer have been adding polycarbonate capacity... 

Much the most important polycarbonate in commercial terms is made from 2,2-di(4-hydroxyphenyl)propane, commonly known as bisphenol A. This polymer was discovered and developed by Farbenfabriken Bayer [92], The synthesis and properties of this and many other polycarbonates were described by Schnell in 1956 [93], The polymer became available in Germany in 1959, and was given the trade name Makrolon by Bayer (in the USA, Merlon from Mobay). General Electric (GE) independently developed a melt polymerisation route based on transesterification of a bisphenol with DPC [94], Their product, Lexan, entered the US market in 1960. The solution polymerisation route using phosgene has since been displaced by an interfacial polymerisation. 

A hospital trolley developed by Bayer and GMP is described. The trolley is equipped with a portable computer for the collection and management of patient information with the aim of reducing medical errors. The main component is a sandwich stracture reaction injection monlded in Bayer s Baydnr 60 PU and consisting of a cellnlar core and a smooth skin. Other components are made of PP, PMMA or polycarbonate. Developments by GMP in the nse of PU foams in refrigerator manufacture are also reviewed, and tnmover fignres are presented for the Company. 

Bayer, A. 1878. Phenol-formaldehyde condensates. Ber. Bunsenges. Phys. Chem., 5 280, 1094. Brunelle, D.J. and Korn, M. 2005. Advances in Polycarbonates. Oxford University Press, New York. Carothers, W.H. 1929. An introduction to the general theory of condensation polymers. J. Amer. Chem. Soc., 51 2548. 

D. Wittmann, H. Peters, J. Schoeps, H.-J. Kress, J. Buekers, and K.-H. Ott, Flame-retardant, high-impact polycarbonate molding compounds, US Patent 5 061745, assigned to Bayer Aktiengesellschaft (Leverkusen, DE), October 29,1991. 

A. Seidel, M. Wagner, J. Endtner, W. Ebenbeck, T. Eckel, and D. Wittmann, Flame-resistant polycarbonate compositions containing phosphorus-silicon compounds, US Patent 7144 935, assigned to Bayer Aktiengesellschaft (Leverkusen, DE), December 5, 2006. 

Plasticization of the Polycarbonate. Makrolon S of Bayer A.G. was used in the experiments. The intrinsic viscosity of this polymer is about 0.55 dl./gram. 

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