Abstract: A process for the synthesis of polycarbonate is disclosed. The process entails reacting in the presence of at least one phosphonium salt as catalyst, at least one diphenol, at least one carbonic acid diester, and at least one alkyl group-substituted phenol chain terminator. The chain terminator is introduced in free form or as a transesterifiable compound under the conditions of the synthesis. The polycarbonate thus produced is suitable for preparing a variety of molded articles.

Abstract: The present invention provides the use of impact resistant, stress cracking resistant copolycarbonates with particularly good low temperature properties for applications in which particularly good low temperature properties are required, e.g., for automobile construction or external applications, and new copolycarbonates themselves.

Abstract: The invention relates to thermoplastic copolycarbonate compositions and moulded parts containing the latter having improved stress cracking resistance and thermal stability.

Abstract: A transesterification process for producing polyester is disclosed. In a first stage of the process there is heated, in an inert gas atmosphere, a first mixture containing at least one dihydroxy compound and at least one diaryl carbonate to form an oligocondensate. In a second stage there is added to the oligocondensate at least one dicarboxylic acid to form a second mixture. The second mixture is heated to a temperature not higher than 290° C. in the presence of a quaternary onium compound as catalyst to form polyester carbonate. Hydroxyaryl formed throughout the process is distilled-off under reduced pressure.

Abstract: A copolyester carbonate especially suitable for the preparation of machine readable data carriers is disclosed.

Abstract: The present invention provides the use of impact resistant, stress cracking resistant copolycarbonates with particularly good low temperature properties for applications in which particularly good low temperature properties are required, e.g., for automobile construction or external applications, and new copolycarbonates themselves.

Abstract: A process for making a high molecular weight (co)polycarbonate resin is disclosed. The process entails (i) obtaining at least one member selected from the group low molecular weight residue (weight average molecular weight 15,000 to 30,000) of aromatic (co)polycarbonate production, waste of (co)polycarbonate production, remainders of (co)polycarbonate production and (co)polycarbonate recyclate (ii) melting the said member in a suitable vessel to obtain a melt and (iii) feeding the melt into a reactor optionally along with at least one bisphenol or oligocarbonate having terminal OH groups and further optionally with a transesterification catalyst, and (iv) subjecting the melt to transesterification reaction at a temperature of 250 to 350° C., at a pressure below 5 mbar and residence time of 0.02-4 hours.

Abstract: A process for determining the suitability of a specific raw material entailed in the melt transesterification of polycarbonate is disclosed. The process entails melting the raw materials including the specific raw material in a reaction vessel and measuring the elapsed time until formation of the first drop of the hydroxyl compound.

Abstract: A thermoplastic molding composition suitable for making articles having good combination of properties is disclosed.

Abstract: A process for the preparation of transparent copolycarbonate is disclosed. The copolycarbonate the molecular structure of which contains more than 35 mole % of units derived from dihydroxydiphenylene is prepared by the melt transesterification process wherein the final temperature of the reaction is reached in less than 40 minutes after reaching the starting temperature.

Abstract: A melt-polymerized polycarbonate is disclosed.

Abstract: A branched melt-polymerized polycarbonate having pronounced non-Newtonian flow behavior is disclosed. The polycarbonate is suitable for preparing molding compositions and the preparation of a variety of molded articles.

Abstract: The invention relates to a method for producing phosphonium phenolates from phosphonium halogenides and phenols.

Abstract: A process for producing polycarbonate is disclosed. The process entails obtaining an oligocarbonate produced by transesterification of diaryl carbonate with dihydroxyaryl compound in the presence of catalysts and introducing the oliogocarbonate into a reactor that enables continuous formation of free films at a rate higher than 10. The reactor including a horizontal cylinder equipped with a heating jacket, at least one vapor outlet, a feed nozzle an outlet nozzle, a rotatable cylindrical basket having a cylindrical perforated wall and annular discs positioned at intervals around the periphery of said basket and along the length thereof, and means for rotating said basket, the interior of said basket including no central shaft, the diameter of the cylindrical basket corresponding to about ⅔ of the diameter of the horizontal cylinder, and said discs being formed of perforated sheet metal.

Abstract: A continuous process for producing polycarbonates by the transesterification of didiaryl carbonates with dihydroxyaryl compounds in the presence of quaternary onium compounds is disclosed. The polycarbonates thus produced are suitable for preparing a variety of articles.

Abstract: A continuous process for producing oligocarbonate is disclosed. The process entails in sequence the steps of a) reacting a dihydroxyaryl compound with a diaryl carbonate in the presence of a catalyst to obtain a melt and avoiding removal of released monohydroxyaryl compound and b) withdrawing the monohydroxyaryl compound by flash evaporation and c) heating the melt obtained under vacuum in an evaporator equipped with sump receiver and d) repeating at least once steps b) and then c) each at gradually increased temperatures and lowered pressures.

Abstract: A method of purifying dihydroxydiphenyl (1), 1

Abstract: The invention relates to thermoplastic copolycarbonate compositions and moulded parts containing the latter having improved stress cracking resistance and thermal stability.

Abstract: The present invention provides the use of impact resistant, stress cracking resistant copolycarbonates with particularly good low temperature properties for applications in which particularly good low temperature properties are required, e.g., for automobile construction or external applications, and new copolycarbonates themselves.

Abstract: An improvement to the melt transesterification reaction of diaryl carbonate with dihydroxy aryl compound is disclosed.