Bayer Aktiengesellschaft

Covestro Deutschland Ag

Bayer Materialscience Ag

Covestro Intellectual Property Gmbh & Co. Kg

Hermann Kauth

Dieter Freitag

Wolfgang Alewelt

Steffen Kuhling

Christian Kords

Manfred Schmidt

Klaus Reinking

Claus H Wulff

Wilfried Haese

Werner Nielinger

Rainer Neumann

Michael Prein

Frieder Heydenreich

Steffen K&uuml;hling

Tony Van Osselaer

Rolf Lanze

Jürgen Heuser

Dieter Wittmann

Wolfgang Ebert

Alexander Meyer

Karsten-Josef Idel

Klaus Horn

Hans-Rudolf Dicke

Gunther Weymans

Ralf Hufen

Johan Vanden Eynde

Frank Gerald Kleiner

Rolf Bachmann

J&uuml;rgen Heuser

Jan Heijl

Jurgen Heuser

Udo Rudolph

Zoltan Kricsfalussy

Uli Franz

Bert Ruytinx

Franky Bruynseels

Andreas Frankenau

Helmut Einberger

Stefaan De Vos

Maarten De Bock

Stephan Laue

Hubert Bosshammer

Christian Eh

Somchai Kanjanasantisak

Heinz-Josef Fullman

The invention relates to an efficient continuous method for producing polycarbonates according to the phase interface method.

Method for producing polycarbonate according to the phase interface method

An improvement to the phase interface process of preparing aromatic polycarbonate is disclosed. The process is characterized in that the phosgenation is carried out at 0 to 40&#xb0; C., and in that the temperature of the reaction mixture at the time of addition of the catalyst at 10 to 40&#xb0; C., and in that the molar ratio of aromatic dihydroxy compounds to phosgene at 1:1.05 to 1:1.20. The polycarbonate thus produced is characterized in its low content of carbamates, making it particularly suitable for the preparation of optical storage media.

Process for the preparation of polycarbonates

An improvement in the continuous two-phase interfacial condensation process for preparing polycarbonate is disclosed. In the process that entails at least one diphenol, phosgene, at least one chain terminator, and optionally branching agents and is carried out in the presence of a catalyst the improvement comprising maintaining the concentration of the catalyst at a level of at least 0.012 mol per mol of diphenol.

A process for producing phosgene having low content of carbon tetrachloride is disclosed. The process entails reacting carbon monoxide with chlorine in the presence of elemental carbon, in a reactor. Critically the temperature of the gas stream emerging from the reactor is restricted to 30 to 80&#xb0; C. and its pressure, measured directly downstream from said reactor is restricted to 120 to 400 kPa. The phosgene thus produced has a content of carbon tetrachloride that is less than 150 ppm.

Phosgene having low content of carbon tetrachloride

A container made of polycarbonate resin is disclosed. The container is characterized in that the polycarbonate is prepared by the phase interface process that is characterized in that the aqueous solution of an alkali salt of a bisphenol used, contains dissolved oxygen in an amount less than 150 ppb. The process for making the container is also disclosed.

Polycarbonate containers

A process for the production of polycarbonate is disclosed. The process, representing an improvement over the known interfacial polycondensation process entails introducing into the loop of a circulating reactor that additionally contains, a residence tank, an optional mixer, a pump, and a heat exchanger (i) an organic phase that contains a solvent for polycarbonate and phosgene and (ii) an aqueous phase that contains an aqueous lye solution, a dihydroxy compound and an optional monophenol to form an emulsion. Maintaining specified temperature and process conditions results in polycarbonate resin having good properties and in waste water that are characterized by their purity.

Process for producing polycarbonates

A process for the preparation of polycarbonate resins having a low yellowness index is described. The process involves converting phosgene with a sodium bisphenolate solution by means of a phase interface process performed with the exclusion of oxygen. The sodium bisphenolate solution used in the process has a dissolved oxygen content of <150 ppb. Also described are optical data storage media prepared from the polycarbonate of the present invention.

Polycarbonates with a low yellowness index

An improvement to the transesterification process for the production of aromatic polycarbonates is disclosed. Into the melt which contains diphenols, carbonic acid diaryl esters and optionally branching agents and at temperatures of 130.degree. C. to 400.degree. C. and in the presence of catalysts there is mixed or passing thereover inert gas in a quantity of at least 0.5 Nm3 per kg of polycarbonate melt.

Improved transesterification process for the production of polycarbonates

The present invention provides a transesterification process for the production of thermoplastic, solvent-free polycarbonates by the use of catalysts that are derived from guanidine.

Guanidine-derived catalyts for preparing polycarbonates by

The present invention relates to a process for producing polymer blends from polycarbonate and mass-polymerized ABS by the condensation of oligocarbonate in the presence of mass-polymerized ABS.

Production of blend systems by the condensation of oligocarbonates in

The invention relates to a two-stage process for the production of thermoplastic, solvent-free lightly branched polycarbonates in the melt using ammonium and/or phosphonium catalysts in the first stage and alkali metal and/or alkaline earth metal catalysts in the second stage.

Two-stage process for the production of thermoplastic polycarbonate

A process for the production of polycarbonates is disclosed. Accordingly, oligocarbonate in the melt is passed through a heated tube and inert gas is simultaneously introduced by injecting to the melt.

Process for the production of polycarbonates

A process for the production of polycarbonates by melt transesterification is disclosed. Accordingly, polycarbonate waste is dissolved in monophenols and at an elevated temperature and in the presence of a catalyst degraded to yield oligocarbonates, diaryl carbonates and diphenols. Following the optional separation of fillers and other additives there is produced by partial recondensation and the distillation of monophenol a higher viscosity oligocarbonate having a OH and aryl carbonate terminal groups and a weight average molecular weight of 8000 to 18000, the oligocarbonate thus produced is then polycondensed to form a polycarbonate resin.

Process for the production of thermoplastic polycarbonates

A two step solvent-free process for the preparation of polycarbonates having a low degree of branching is disclosed. Accordingly, the process comprise

Process for the preparation of thermoplastic polycarbonates

The present invention relates to a process for isolating polycarbonates in which a solution of polycarbonate in an organic solvent is dispersed with steam and which is characterized in that the resulting suspension of polycarbonate particles, condensed water and water/solvent vapor is subsequently dried in a tube with cross-sectional constrictions.

Process for isolating polycarbonates from their solutions with tube

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Krefeld, Germany

Hermann Kauth