Bayer Aktiengesellschaft

Jurgen Heuser

Gunther Weymans

Claus H Wulff

Gerhard Friedhofen

Volker Serini

Hans-Helmut Schwarz

Hans-Josef Buysch

Dieter Freitag

Wolfgang Alewelt

Jurgen Kirsch

Rainer Neumann

Hermann Kauth

Rolf Kubens

Lothar Meier

Zoltan Kricsfalussy

Reinhard Schomacker

Otto Billinger

Jurgen Kadelka

Rolf Treckmann

Karola Brudermanns

Hanns-Ingolf Paul

Konrad Hable

Klaus Elgeti

Gunther Jeromin

Dieter Frietag

The invention relates to ultrafine suspensions of bisphenol, sodium hydroxide and water for the production of polycarbonates by the two-phase interfacial process. According to the invention, these suspensions are prepared by cooling bisphenolate concentrations near the solubility limit in aqueous sodium hydroxide with intensive mixing at relatively high temperatures and precipitating bisphenolate or more bisphenolate in the form of fine droplets during the cooling process. The ultrafine suspensions provide for a high volume/time yield in the interfacial reaction.

Production of ultrafine suspensions of bisphenol, sodium hydroxide and

A continuous process for the removal of electrolytes and catalysts from organic polycarbonate solutions is disclosed. Accordingly, a solution obtained in the course of the two-phase interfacial reaction for the preparation of polycarbonate, containing thermoplastic aromatic polycarbonate and an organic solvent and up to 10 parts by weight water as well as residues of chain terminators, branching agents and diphenols is washed with water and/or hydrochloric acid through a cascading train of centrifuges. The resulting polycarbonate resin is characteristically of extremely low iron content.

Washing of polycarbonates with cascading train of centrifuges

An improvement to the continuous process for the production of polycarbonates by interphase polycondensation is described. Accordingly, the organic phase and the aqueous phase are combined in a tube, forming chlorocarbonic acid ester and further alkali hydroxide is added at, or shortly after, the maximum concentration of said ester is reached. The resulting emulsion is then changed to an oil-in-water emulsion which is then separated and worked up in known manner.

Continuous production of polycarbonates

A process for isolating polymers from their solvents by addition of fluids containing carbon dioxide at temperatures of 30.degree. to 280.degree. C. and under pressures of 1 to 1,000 bar is disclosed. The process is characterized in that the concentration of the polymers in their solvents is between 5% and 80% by weight and the fluid containing carbon dioxide consists of at least 50% by weight carbon dioxide.

Process for isolating polymers from their solvents using liquids

Fogging of plastics containing polymer plasticizers is reduced by treating the polymer plasticizers with water vapor in the melt.

Process for reducing fogging due to plasticizers in plastics

A process for the production of mixtures of alkylated aromatic polyhydroxy compounds by reacting alkylated phenols with carbonyl compounds, wherein acidic organic ion exchangers are used as catalysts and commercial dialkyl phenols as the phenol and any unreacted starting phenols separated off are completely recycled into the process without intermediate purification, and the application of the thus produced polyhydroxyl compounds for making thermoplastic polycarbonates.

Process for the production of mixtures of alkylated aromatic hydroxy

A process for the preparation of a 4,4'-dihydroxy-3,3',5,5'-tetraalkyl-diphenylalkane by reacting a 2,6-dialkyl phenol with a ketone in the presence of an acid organic ion exchanger wherein said acid ion exchanger is a macroporous resin with an average pore diameter of at least 300 A.

Process for the preparation of

The present invention is concerned with aromatic thermoplastic polycarbonates which contain at least about 0.5 mole % of structural units derived from 1,1,3,4,6-pentamethyl-3-(3,5 dimethyl-4-hydroxyphenyl)-indan-5-ol. The polymers disclosed herein may be homopolymers of these units or copolymers with other aromatic dihydroxy compounds and/or tri or higher functional branching agents. These homopolymers or copolymers may be used per se or they may be blended with other thermoplastic resins, particularly other aromatic polycarbonates. In addition, these polymers may be used to prepare coatings which may be cross-linked by heat treatment or radiation or they may be used as the base for graft polymerization.

1,1,3,4,6-Pentamethyl-3-(3,5-dimethyl-4-hydroxyphenyl)-indan-5-ol

An improved process for the preparation of an .alpha.,.alpha.,.alpha.',.alpha.'-tetramethyl-phenylene-biscarbinol by the oxidation of at least one diisopropyl benzene with air or oxygen at elevated temperatures in the presence of an aqueous solution of a strong alkali, the improvement comprises carrying out the oxidation with a carbinol content of at least 52% by weight in the organic phase and an alkali concentration of at least 8% by weight based on the aqueous phase and 1 to 10% by weight based on the organic phase.

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Krefeld, Germany

Jurgen Heuser