Abstract: Acidic impurities in dihydroxyaromatic compounds such as bisphenol A, as illustrated by sulfonic acids and mercaptocarboxylic acids, can have an adverse effect on the molecular weight of a polycarbonate prepared therefrom by transesterification. The same is true of acidic impurities in diaryl carbonates such as diphenyl carbonate, as illustrated by salicylic acid and ferric chloride. The reagents are analyzed for these impurities. Based on the analysis, the reagents are discarded or recycled, or a compensatory amount of alkali metal hydroxide is employed as a catalyst in the reaction.

Abstract: A melt method of preparing polycarbonate having a predetermined number average molecular weight and percent endcapping is described. A computerized process model is used to determine the reaction parameters to be employed in order to furnish the product polycarbonate possessing the desired Mn and %EC. Reaction parameters of importance include a suitable starting molar ratio of diaryl carbonate to dihydroxy aromatic compound, the most appropriate reaction time, reaction temperature and pressure ranges. The target polycarbonate is then prepared using reaction parameters indicated by the process model in a reactor which forms an element of the process model. Characteristics of the reactor which may be included in the process model include agitation rate and reflux ratio during the distillative removal of hydroxy aromatic compound formed as a by-product during the polymerization.

Abstract: This invention provides a method for preparing polycarbonates, which utilizes polycondensation catalysts of the formula Cs+An−, wherein An− represents anions such as CH3SO3−, NH2SO3−, C2H2O4−, BF4−, B(C6H5CH3)4−, and CH3C6H4SO3−. We have found that this new class of catalysts provides excellent polymerization rates for the preparation of Bisphenol A polycarbonate from the melt polymerization of diphenyl carbonate and Bisphenol A. Moreover, the catalysts of the invention were found to be very selective in substantially reducing the level of branching side reaction, i.e., formation of Fries product, normally associated with the melt polycarbonate process.

Abstract: The manufacture of polycarbonates can be accomplished via an ester interchange reaction of a dihydroxy compound and a carbonic acid diester. The method, which can be a single or multi-stage process wherein the total amount of alkali metal compounds and alkaline earth metal compounds contained as impurities is 1×10−7 moles or less per mole of dihydroxy compound used as raw materials, and the catalyst employed is an ammonium and/or phosphonium compound, a compound which decomposes or volatilizes at a temperature of 100 to 300° C., and/or an alkali metal phosphorous containing inorganic salt and/or alkaline earth metal phosphorous-containing inorganic salt.

Abstract: Copolycarbonates containing such structural units as birefringence-reducing or “soft block” units are prepared by conducting a reaction, such as melt polymerization or equilibration, between a precursor polycarbonate and a monomer, polycarbonate oligomer or high molecular weight polycarbonate which is a source of other structural units. The crystallinity of the resulting precursor copolycarbonate or one of the reagents employed in its preparation is enhanced and the precursor copolycarbonate is subjected to solid state polymerization.

Abstract: This invention provides a method for preparing polycarbonates, which utilizes polycondensation catalysts of the formula Ax+MF6−x, wherein A is an alkali metal or alkaline earth cation; M is a transition metal of group IVA or VA, or M is a p-block metal of group IIIB, IVB or VB; and x is 1, 2, or 3. We have found that this new class of catalysts provide excellent polymerization rates for the preparation of Bisphenol A polycarbonate from the melt polymerization of diphenyl carbonate and Bisphenol A. Moreover, the catalysts of the invention were found to be very selective in substantially reducing the level of branching side reaction, i.e., formation of Fries product, normally associated with the melt polycarbonate process.

Abstract: This invention relates to a method for the preparation of polycarbonate by the melt process comprising reacting a diphenol and a diarylcarbonate in the presence of a catalyst system comprising a catalytically effective amount of an alkali and/or alkali earth metal salt of a non volatile acid and a base.

Abstract: This invention provides a method for preparing polycarbonates, which utilizes polycondensation catalysts which are salts of certain phenanthroline compounds. We have found that this new class of catalysts provide excellent polymerization rates for the preparation of Bisphenol A polycarbonate from the melt polymerization of diphenyl carbonate and Bisphenol A. Moreover, the catalysts of the invention were found to be very selective in substantially reducing the level of branching side reaction, i.e., formation of Fries product, normally associated with the melt polycarbonate process.

Abstract: This invention relates to mixed dialkali metal salts of sulfuric acid containing at least one cesium equivalent useful in catalyst systems in melt polymerizations. The catalysts provide product with low branching side reaction products and good properties.

Abstract: A melt condensation polymerization process for preparing siloxane copolycarbonates is provided. The process includes reacting an aromatic dihydroxy compound, carbonic acid diester, hydroxyaryl terminated polydiorganosiloxane and catalyst with a salt.

Abstract: The present invention relates to a method for the preparation of polycarbonate comprising preparing a polycarbonate by a melt process by reacting a diphenol and a diaryl carbonate in the presence of a catalytically effective amount of one or more alkali and or alkali earth metal salts of chelating agents. Suitable chelating agents include nitrilotriacetate and EDTA.

Abstract: A method of preparing polycarbonate by the melt process comprising the steps of: a) melting a dihydric phenol and a diester of carbonic acid for a time and at a temperature sufficient to form a melt; and thereafter introducing a catalyst composition comprising a tetraorganophosphonium salt or a derivative thereof and 1) an alkali and/or alkali earth metal compound or derivative thereof or 2) a less active alkali and/or alkali earth metal derivative thereof into the melt; and b) oligomerizing the product from step a) to a number average molecular weight of from about 3000 to about 7500; and c) polymerizing the product from step b) to a number average molecular weight of from about 16,000 to about 35,000.

Abstract: The present invention relates to a method for the preparation of polycarbonate comprising preparing a polycarbonate by a melt process by reacting a diphenol and a diaryl carbonate in the presence of a catalytically effective amount of one or more alkali metal salts of oxoacids of sulfur.

Abstract: This invention relates to salts of aryl sulfonic acids useful in catalyst systems in melt polymerizations. Suitable alkali metal salts of aryl sulfonic acids include alkali metal salts of p-toluenesulfonic acid. The invention further relates to polycarbonates prepared using the catalyst systems of the present invention, and articles made from these polycarbonates.

Abstract: Copolycarbonates containing such structural units as birefringence-reducing or "soft block" units are prepared by conducting a reaction, such as melt polymerization or equilibration, between a precursor polycarbonate and a monomer, polycarbonate oligomer or high molecular weight polycarbonate which is a source of other structural units. The crystallinity of the resulting precursor copolycarbonate or one of the reagents employed in its preparation is enhanced and the precursor copolycarbonate is subjected to solid state polymerization.

Abstract: Polycarbonates, such as bisphenol A polycarbonates, having end groups derived from a di-t-alkylphenol such as 3,5-di-t-butylphenol have very low electrostatic charges. They are thus useful in applications where static charge is a problem, such as automotive headlamps and optical data recording media.

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: A static resistant polycarbonate composition is provided comprising a polycarbonate, at least one mold release agent, and at least one antistatic agent. The disclosed composition optionally comprises a heat stabilizer. Static resistant compact disks are molded from the polycarbonate composition.

Abstract: Quaternary salts having a double helix structure are prepared by the reaction of dihydroxyaromatic compound, preferably a bisphenol, with an alkali metal hydroxide and a quaternary salt, such as a tetraalkylammonium or hexaalkylguanidinium chloride. The quaternary salts and their alkaline hydrolysis products are useful as catalysts in various reactions, including imide formation from bisphenol salts and halo- or nitro-substituted phthalimides and redistribution and equilibration of polycarbonates.

Abstract: Branched polycarbonates are prepared by the reaction of a linear or branched polycarbonate with a branching resin having a molecular weight up to about 3,000, typically a novolak or a bisphenol polymer. The reaction preferably takes place in the presence of a carbonate equilibration catalyst such as a quaternary bisphenolate.