Bayer Aktiengesellschaft

Melanie Moethrath

Rolf Wehrmann

Friedrich-Karl Bruder

Wolfgang Ebert

Alexander Meyer

Johann Rechner

Uwe Hucks

Silke Kratschmer

Lothar Bunzel

Hans Deml

Werner Heuer Helmut

Polycarbonates, polyester carbonates and polyesters with special branched terminal groups

A process for the production of high molecular weight aliphatic polycarbonates is disclosed. The process entails a first stage wherein a low molecular weight aliphatic polycarbonate is prepared and a second stage where the low molecular weight aliphatic polycarbonate is condensed with diaryl carbonate in a melt transesterification process to form a high molecular weight aliphatic polycarbonate. The resulting high molecular weight aliphatic polycarbonate is suitable for the production of extrudates, films and molded articles.

Production and use of high molecular weight aliphatic polycarbonates

A process for preparing a melt transesterification catalyst is disclosed. The process entails (i) obtaining a phenol adduct of phosphonium phenolatein the form of crystalline solid and (ii) storing the solid phenol adductin a closed container at relative humidity of 30 to 70 % and at temperature of &minus;30 to 50&deg; C. The thus prepared catalyst is suitable in the production of polycarbonate in the melt transesterification process.

Storage of phosphonium phenolate catalysts and their use as interesterification catalysts

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Düsseldorf, Germany

Melanie Moethrath