Bayer Aktiengesellschaft

Bayer Materialscience Ag

Bayer Antwerpen N.v.

Steffen Kühling

Thomas König

Klemens Kohlgrüber

Jörg Kirchhoff

Franky Bruynseels

Dirk Van Meirvenne

René De Cleyn

Friedrich-Karl Bruder

Wilfried Haese

Thomas Bieringer

Melanie Möthrath

Michael Bödiger

A process for the isolation of polycarbonate produced by the interfacial polymerization process is disclosed. Accordingly, the process entails (a) evaporating the organic solvent from the solution that contains solvent and polycarbonate to obtain a material system that contains 90 to 99.95% polycarbonate, the percent being relative to the weight of the system, and (b) passing the material system through inlet openings of a separating vessel to obtain a plurality of streams of polycarbonate, on entry into the inlet openings said material system being supersaturated with volatile constituents to an extent of at least 1 bar and having a temperature of 250&#xb0; to 340&#xb0; C. and a flow rate of 0.1 to 20 kg/hour, and (c) degassing the streams in the separating vessel wherein the pressure is 0.1 to 20 mbar to effect degassing of the polycarbonate.

Process for the production of polycarbonate

The invention describes a process for the preparation of polycarbonate. The process includes

Process for the preparation of polycarbonate

A process for the preparation of optical data carriers made of a particualr polycarbonate is disclosed. The polycarbonate is prepared by the phase boundary process that entails reacting at least one dihydroxydiarylalkane in the form of its alkali metal salts with phosgene in the heterogeneous phase in the presence of sodium hydroxide solution and an organic solvent. The process is characterized in that the feedstock have but low content of Fe, Cr, Ni, Zn, Ca, Mg, Al metals or homologues thereof, and in that the organic solvent is separated off, and in that the polycarbonate which is obtained is worked up. The resulting polycarbonate is particularly useful in producing optical data carriers.

Optical data carriers and method for producing the same

Polycarbonate substrates, the preparation of which is based on 1,1-bis-(4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, and their use for producing shaped articles with particularly high purity and extremely high surface brilliance and also the shaped articles which can be produced from the polycarbonate substrate are described.

Polycarbonate substrates

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Meerbusch, Germany

Steffen Kühling