Abstract: A method is provided for making cyclic carbonates of 2,2-bis(4-hydroxyphenyl)-1,1-dichloroethylene, such as the cyclic trimer, by effecting the polymerization of the aforementioned bis (4-hydroxyphenyl)dichloroethylene to a linear polycarbonate, and then agitating a solution of the resulting polycarbonate in the presence of a tertiary ogranic amine. The cyclic carbonates made by the aforementioned process are useful as flame retardants in polycarbonates.

Abstract: A process for poly(ester-carbonates) from dihydric phenols, especially bisphenol A; aromatic or cycloaliphatic dicarboxylic acids, especially terephthalic acid; and phosgene as carbonate precursor wherein a reaction of the acid and phosgene is carried out in a first stage forming dicarboxylic acid chloride; and then phosgene and bisphenol A are added in separate streams, simultaneously during most of the second or condensation stage. Thereby only one kettle is required for carrying out the complete polymer production.

Abstract: The present invention relates to the preparation of aromatic polycarbonates, by the two-phase interface process, from diphenols, preferably from halogen-free diphenols, characterized in that aromatic monosulphonic acid chlorides are used as chain stoppers in amounts of about 2 mol % to 20 mol %, preferably in amounts of about 2.5 mol % to 10 mol %, relative to mols of the diphenols employed. In addition, the present invention relates to the aromatic polycarbonates obtainable by the process according to the invention.

Abstract: The invention relates to a process for the preparation of branched, thermoplastic, high-molecular weight and soluble polycarbonates having improved properties, by incorporation of 3,3-bis-(4-hydroxyaryl)-oxindoles as a branching agent. The invention further relates to the polycarbonates obtained in accordance with this process.

Abstract: The present invention relates to a process for the preparation of branched thermoplastic polycarbonates, characterized in that diphenols are completely reacted with about 0.05 to about 2.0 mol %, relative to mols of diphenols, of cyanuric chloride in a primary reaction, while controlling the pH and temperature and in the presence of a co-solvent, and thereafter the products are subjected to polycondensation, in accordance with known methods of the phase boundary process, to give high-molecular weight, branched polycarbonates. The invention further relates to the branched polycarbonates prepared by this process.

Abstract: Thermoplastic polycarbonates are prepared by interfacial polymerization wherein carbonyl halides, dihydric phenols and a catalytic amount of a 1,1-dimethyl urea compound is reacted.The polycarbonates thus prepared are useful as moldable resins in a manner well known in the art.

Abstract: A process is provided for preparing a polycarbonate composition with excellent weatherproof properties. The process comprises adding an ultraviolet absorbing compound having a hydroxy group which contributes at least partially to the molecular weight modifier to an oligomeric polycarbonate which is obtained by the reaction of a dioxy compound with phosgene, and then condensing said oligomeric polycarbonate to polymerize the same.

Abstract: The cyclic carbonate trimer of 2,2-bis(4-hydroxyphenyl)-1,1-dichloroethylene is provided which can be employed as a flame retardant for a variety of thermoplastic organic polymers, such as high molecular weight bisphenol-A polycarbonate. This cyclic carbonate trimer also can be employed as a precursor for making high molecular weight phenyl dichloroethylene polycarbonate.

Abstract: The present invention provides thermoplastic aromatic polycarbonates and a process for their production according to the phase boundary polycondensation process, characterized in that tertiary amines are employed as catalysts and are distilled beforehand over about 0.3-10% by weight, relative to the weight of the tertiary amine, of reducing agents and/or acid anhydrides with the exclusion of atmospheric oxygen.

Abstract: Aromatic polycarbonates having carbamate end groups are prepared using a terminating amount of ammonia, ammonium compounds, primary cycloalkyl, aliphatic, or aralkyl amines and secondary cycloalkyl, alkyl, or aralkyl amines. The products of this invention have been found to have a relatively high limited oxygen index compared to polycarbonates without carbamate end groups.