Bayer Aktiengesellschaft

Bayer Materialscience Ag

Bayer Ag Konzernverwaltung Rp

Bayer Intellectual Property Gmbh

Covestro Deutschland Ag

Johan Vaes

Johann Rechner

Claus H Wulff

Kaspar Hallenberger

Tony Van Osselaer

Jurgen Hinz

Kurt-Peter Meurer

Ignace Hooftman

Thomas König

Gerhard Fennhoff

Rainer Neumann

Michael Prein

Johan Vanden Eynde

Frieder Heydenreich

Michael Bierdel

Klemens Kohlgrüber

Gottfried Zaby

Alfred Eitel

Jörg Kirchhoff

Michael B&ouml;diger

Gabriel Denecker

Werner Verhoeven

Bert Ruytinx

Heinrich Steude

Hugo Obermann

Dirk Van Meirvenne

René De Cleyn

Stefaan De Vos

Thomas Bamberger

Frank Quaeyhaegens

Willy Van Herck

The invention relates to an apparatus and a process for devolatilizing solvent-containing polycarbonate solutions. By employing the inventive apparatus, polycarbonates with low residual values of volatile constituents are produced from solvent-containing polymer melts, which improved optical properties, especially yellowness index, with the aid of an apparatus combination of a heatable tubular devolatilizer and a vented extruder.

Device and method for degassing solvent-containing polycarbonate solutions

A process for the production of 2,2-bis(4-hydroxyphenyl)propane (BPA) is disclosed. The process that entails reacting acetone with phenol in the presence of cross-linked sulfonated polystyrene resins is characterised in that BPA is separated from the reaction solution downstream of the reaction unit by means of a multi-stage vacuum distillation and a subsequent single- or multi-stage layer crystallisation. The by-product stream with accumulated by-products is returned downstream of the reaction unit.

Bisphenol production

The invention relates to a process for drying polymeric powders and polymeric agglomerates, in particular thermoplastic aromatic polycarbonate or other thermoplastic polymers such as, for example, acrylonitrile-butadiene-styrene copolymer, in the melt, whereby thermoplastic polymeric powders or polymeric agglomerates containing water or solvent or both are freed from adhering moisture and contained solvent, accompanied by melting, in an apparatus provided with rotating baffles for cleaning the walls of the apparatus and for distribution and transport of the material being dried, by heat input through the walls or through the rotating baffles or both as well as by heat input as a result of shearing action. The process of drying and that of melting for the subsequent granulation are thereby combined.

Process for drying polymeric powders and polymeric agglomerates

A process for preparing bisphenol A which has a purity of at least 99.95 wt. % of p,p-bisphenol A (BPA). Thermally stable and colour-stable BPA purified in accordance with the invention produces improved thermal and colour stability and improved optical transparency in polymers such as e.g. polycarbonates prepared therefrom.

Process for the purification of bisphenol

The invention relates to a method for the purification by distillation of p,p-bisphenol A from the melt. The p,p-bisphenol A melt thus obtained is highly heat-stable, stable in storage and colour-stable, is free from high-boiling components and no longer contains any surface-active or non-distillable metal, salt, acid or polymer components and no sulphur-containing components; o,p-BPA and phenol are removed and the low-boiling components are scarcely detectable.

Method for the preparation of ultra-pure bisphenol A and the use thereof

Growing community of inventors

Kalmthout, Belgium

Johan Vaes