Bayer Aktiengesellschaft

Bayer Materialscience Ag

Uwe Hucks

Silke Kratschmer

Hugo Vernaleken

Dieter Freitag

Claus H Wulff

Erhard Tresper

Steffen Kuhling

Thomas Fischer

Lothar Bunzel

Ludwig Bottenbruch

Volker Serini

Michael Prein

Gottfried Zaby

Rolf Bachmann

Annett K&ouml;nig

Franz Ferdinand Rhiel

Wolfgang Herrig

Werner Waldenrath

Bernhard Schulte

Hans-Leo Weber

Jurgen Kadelka

Thomas König

Gunther Weymans

Rolf Lanze

Claus Burkhardt

Harald Selbeck

Melanie Möthrath

Gunter Lehr

James Mason

Johann Rechner

Dieter Margotte

Helmut-Werner Heuer

Wolfgang Alewelt

Jurgen Kirsch

Werner Nielinger

Joachim Wank

Martin Ullrich

Johan Vanden Eynde

Wolfgang Cohnen

Kaspar Hallenberger

Steffen K&uuml;hling

John W Goossens

Heinrich Schuchardt

Karl-Heinrich Meyer

Eike Schulz Van Endert

Frank Druschke

Heinrich Hähnsen

Marc Buts

Reinhard Schomacker

August Bockmann

Kurt Weirauch

Klaus Schebesta

Gunther Lenz

Melanie Moethrath

Karl-Dieter Lohr

Claus-Ludolf Schultz

Lydia Simon

August Horsthemke

Hans-Jurgen Meissner

Klaus Schr&ouml;der

Thomas K&ouml;nig

Gerhard Emmer

G&uuml;nther Jeromin

Hans-Peter Hoffmann

Manfred Schraut

A multi stage process for the production of polycarbonates having low monomer content is disclosed. The process entails, in sequence, (i) transesterifying in the melt at least one dihydroxyaryl compound with at least one diaryl carbonate in the presence of at least one onium catalyst to produce a polycondensate that contains monomers, (ii) introducing into the polycondensate an inhibitor in an hypostoichiometric amount in relation to the catalyst and (iii) reducing in a finishing reactor the content of monomers in said polycondensate. The polycarbonate thus produced is characterized in that it contains less than 350 ppm of diphenyl carbonate, less than 40 ppm of 2,2-bis-(4-hydroxyphenyl)propane and less than 150 ppm of phenol.

Transesterification process for the production of polycarbonates having a low content of volatile compounds

A process for stripping volatile constituents from polymer melts is disclosed. The process entails introducing the polymer melt into a horizontally oriented cylindrical device that contains a plurality of perforated disks rotating about a common horizontally oriented, externally driven shaft bringing the melt and disks into contact in a manner calculated to constantly renew the surface of the melt to be stripped. Also disclosed is an apparatus suitable for the process.

Process for stripping monomers and other volatile constituents from polymer melts

The invention relates to a continuous method for producing polycarbonates by transesterifying diaryl carbonates with dihydroxyaryl compounds in the presence of quaternary onium compounds. The invention also relates to polycarbonates produced thereby and products produced from said polycarbonates.

Method for producing polycarbonates

A process for making a high molecular weight (co)polycarbonate resin is disclosed. The process entails (i) obtaining at least one member selected from the group low molecular weight residue (weight average molecular weight 15,000 to 30,000) of aromatic (co)polycarbonate production, waste of (co)polycarbonate production, remainders of (co)polycarbonate production and (co)polycarbonate recyclate (ii) melting the said member in a suitable vessel to obtain a melt and (iii) feeding the melt into a reactor optionally along with at least one bisphenol or oligocarbonate having terminal OH groups and further optionally with a transesterification catalyst, and (iv) subjecting the melt to transesterification reaction at a temperature of 250 to 350&#xb0; C., at a pressure below 5 mbar and residence time of 0.02-4 hours.

Process for the recycling of polycarbonates

A continuous process for producing oligocarbonate is disclosed. The process entails in sequence the steps of a) reacting a dihydroxyaryl compound with a diaryl carbonate in the presence of a catalyst to obtain a melt and avoiding removal of released monohydroxyaryl compound and b) withdrawing the monohydroxyaryl compound by flash evaporation and c) heating the melt obtained under vacuum in an evaporator equipped with sump receiver and d) repeating at least once steps b) and then c) each at gradually increased temperatures and lowered pressures.

Process for producing oligocarbonates

A branched melt-polymerized polycarbonate having pronounced non-Newtonian flow behavior is disclosed. The polycarbonate is suitable for preparing molding compositions and the preparation of a variety of molded articles.

Polycarbonate having pronounced shear thinning behavior

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

The invention relates to a novel polycarbonate and its use a material in the production of molded articles and semifinished products, especially for transparent articles such as data memories or radio compact discs, slabs, cellular sheets, films, housings, panes, especially panes for motor vehicles, diffusion glasses, but also for electrical applications or the constructions of houses.

Polycarbonate and molded polycarbonate articles

A process for the production of phosphonium phenolates is disclosed. The process entails reacting a phosphonium halide and phenol in an aqueous alkaline solution. The phosphonium phenolate produced is separated from the synthesis mixture by crystallization

Method for producing phosphonium phenolates

Solid particles containing 10 to 90 parts by weight of a dihydroxy compound and 10 to 90 parts by weight of a carbonic acid ester are disclosed. Also disclosed is a process for the production of these particles, an apparatus suitable for the process and a method for their use in production of polycarbonate by transesterification of carbonic acid esters with dihydroxy compounds.

Solid particles

A process for producing polycarbonate is disclosed. The process entails transesterification of at least one carbonic ester with a mixture that contains dihydroxyl compound and phenol. The amount of bisphenol A in the mixture is 10 to 100 mol % relative to the amount of dihydroxyl compound and phenol is present in the mixture in an amount of 0.1 to 200% relative to the weight of bisphenol A.

Method for producing polycarbonate

An improvement to the melt transesterification reaction of diaryl carbonate with dihydroxy aryl compound is disclosed. The improvement entails the following steps (i) introducing the resulting vapor stream at the mid-height of a first distillation column, and (ii) separating the vapor stream into a top product containing high purity monohydroxy aryl compound and a first bottom product, and (iii) recycling the high purity monohydroxy aryl compound of (ii) to the reaction, and (iv) introducing the first bottom product at mid-height of a second distillation column, and (v) separating said first bottom product into high boiling bottom by-product and overhead remaining constituents, and (vi) introducing the overhead remaining constituents at mid-height of a third distillation column, and (vii) separating said overhead remaining constituents into overhead low-boiling fractions and bottom or product side stream that contains diaryl carbonate product, and (viii) recycling the diaryl carbonate product directly to the transesterification reaction.

Process for producing polycarbonate

Polycarbonate having a low shear thinning behavior

A process for producing polycarbonate is disclosed. The process entails obtaining an oligocarbonate produced by transesterification of diaryl carbonate with dihydroxyaryl compound in the presence of catalysts and introducing the oliogocarbonate into a reactor that enables continuous formation of free films at a rate higher than 10. The reactor including a horizontal cylinder equipped with a heating jacket, at least one vapor outlet, a feed nozzle an outlet nozzle, a rotatable cylindrical basket having a cylindrical perforated wall and annular discs positioned at intervals around the periphery of said basket and along the length thereof, and means for rotating said basket, the interior of said basket including no central shaft, the diameter of the cylindrical basket corresponding to about &frac23; of the diameter of the horizontal cylinder, and said discs being formed of perforated sheet metal.

Process for continuous production of polycarbonates and a reactor therefor

A process for the synthesis of polycarbonate is disclosed. The process entails reacting in the presence of at least one phosphonium salt as catalyst, at least one diphenol, at least one carbonic acid diester, and at least one alkyl group-substituted phenol chain terminator. The chain terminator is introduced in free form or as a transesterifiable compound under the conditions of the synthesis. The polycarbonate thus produced is suitable for preparing a variety of molded articles.

Method for producing modified polycarbonates

Growing community of inventors

Alpen, Germany

Uwe Hucks