Abstract: The invention relates to polycarbonates suitable for use in optical articles; the polycarbonates contain residues of alicyclic bisphenols and have properties particularly suited for use in high density optical data storage media. The polycarbonates further contain residues of other monomers, such as SBI and its derivatives; bisphenols, such as bisphenol A; CD-1 and its derivatives or some combination of each.

Abstract: High flow brominated polycarbonates, useful as flame retardant additives for other polymers such as polyesters, are obtained by equilibration of a brominated aromatic polycarbonate such as a tetrabromobisphenol A homo- or copolycarbonate with a di- or polyhydroxy aromatic compound such as bisphenol A, or a diaryl carbonate, and an equilibration catalyst, under conditions such that the weight average molecular weight of the brominated polycarbonate is reduced by at least 35%. Preferred equilibration catalysts are Group I metal carboxylates, such as sodium stearate, and hexaalkylguanidinium salts.

Abstract: Novel methods and compositions for improving the flame retardant capabilities of aromatic-based polymers like polycarbonate are disclosed. Other important polymer properties are substantially maintained, such as transparency. One aspect of the invention is directed to a flame retardance additive which comprises a copolymer of an aryl-containing silicone compound and a diorganic polysiloxane compound. In some preferred embodiments, the aryl-containing silicone compound is triphenyl- or diphenyl-based. This invention is also directed to new polymer compositions, which comprise an aromatic-based polymer and the flame retardance additive described above. The polymer compositions can be molded into a variety of articles which have a very useful combination of properties.

Abstract: Copolycarbonates having low intrinsic birefringence comprise structural units derived from hydroxyphenylindanol, from resorcinol, alkylenedioic acid or eugenolsiloxane, and, optionally, from a bisphenol, preferably bisphenol A. The copolycarbonates are useful for the fabrication of optical data recording media such as compact disks.

Abstract: The level of anhydride linkages in copolyestercarbonates is decreased by preparing the copolyestercarbonate interfacially in a two-step method from at least one dihydroxyaromatic compound and at least one dicarboxylic acid. The first step is conducted at a pH in the range of about 4.5-9.5, employing the combination of a hexaalkylguanidinium salt as a phase transfer catalyst and a tertiary amine such as triethylamine. The proportion of the phase transfer catalyst and tertiary amine are usually in the range of about 1-5 and about 0.01-5.0 mole percent, respectively, based on total dihydroxyaromatic compound and dicarboxylic acid employed. In the second phosgenation step, the pH is raised to at least 10 and a stoichiometric phosgene excess of at least 5% is introduced.