Bayer Materialscience Ag

Covestro Deutschland Ag

Bayer Intellectual Property Gmbh

Bert Ruytinx

Rolf Wehrmann

Friedrich-Karl Bruder

Wolfgang Ebert

Johan Vanden Eynde

Alexander Meyer

Johann Rechner

Michael Bierdel

Frank Bruynseels

Ing Johan Vaes

Helmut-Werner Heuer

Wilfried Haese

Thomas König

Hermann Kauth

Christian Kords

Klemens Kohlgrüber

Alexander Karbach

Rolf Bachmann

Jörg Kirchhoff

Thomas Koenig

Uli Franz

Lars Obendorf

Johan Vaes

Joerg Kirchhoff

Klemens Kohlgrueber

Johann Seeba

Stefaan De Vos

Helmut Einberger

Andreas Frankenau

Burkhard Reitze

Matthias Voetz

Rainer Mellis

Delef Michalski-Vollmer

Christian Eh

Thomas Winzen

Andreas Pogoda

Gabriele Kretschmar

Detlef Michalski-Vollmer

Bernhard Nietzwetzki

The invention relates to polycarbonates with extremely low residual levels of volatile constituents and thermal degradation products, and also improved optical properties, especially Yellowness Index (YI) and good thermal stability, from solvent-containing polymer melts. The invention further relates to an apparatus and a process for preparing these polycarbonates with the aid of a devolatilizing extruder with at least three devolatilizing zones, and zones for introducing entraining agent into dispersion are present upstream of at least three devolatilizing zones.

Ultra-high purity polycarbonates having good inherent color and thermal resistance and a device and a method for producing the same

The invention relates to the use of alkylphenols for adjusting the molecular weight of polycarbonates and compositions of these polycarbonates with additives chosen from the group of heat stabilizers, mold release agents and light stabilizers, the use thereof for the production of moldings and moldings obtainable therefrom.

Alkylphenol for adjusting the molecular weight, and polycarbonate compositions having improved properties

A process for treating the working surfaces of equipment used in the production and processing of polycarbonate is disclosed. The thermal treatment in an oxidative atmosphere results in resin and molded articles having improved optical quality.

Process for treatment of metal surfaces

Continuous processes for preparing polycarbonates having a weight average molecular weight M, of 15,000 to 200,000 g/mol, the processes comprising reacting a dihydroxydiarylalkane and phosgene in the presence of a catalyst in a phase boundary process comprising: continuously dispersing in a disperser an organic phase comprising at least a portion of the phosgene and a solvent suitable for the polycarbonate and an aqueous phase comprising the dihydroxydiarylalkane, water and an alkali solution present in an amount of 1.5 to 2.5 moles per mole of the dihydroxydiarylalkane, to form a mixture; reacting the mixture in a first reactor with a residence time of less than 0.5 seconds; further reacting the mixture in a second reactor with addition of further alkali solution and, optionally, a chain terminator; and effecting further condensation in a third reactor with addition of further alkali solution and, optionally, a chain terminator, in the presence of the catalyst.

Phase boundary processes for preparing polycarbonates

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

Growing community of inventors

Halen, Belgium

Bert Ruytinx