Bayer Aktiengesellschaft

Hugo Obermann

Gottfried Zaby

Claus H Wulff

Clemens Casper

Thomas Bamberger

Dieter Freitag

Karsten-Josef Idel

Klaus Horn

Jurgen Kirsch

Richard Weider

Steffen Kuhling

Tony Van Osselaer

Gabriel Denecker

Johan Vaes

Stefaan De Vos

This invention relates to a process for the production of polycarbonate agglomerate of high bulk density from polycarbonate solutions, in which the organic solvent is stripped from a solution of polycarbonate by means of steam, and which is characterised in that the resulting suspension of polycarbonate particles, condensed water and water- and solvent vapor is fed in a tube or tubular heat exchanger to a separator which is partially filled with water and which is under elevated pressure. The polycarbonate agglomerates are discharged, together with part of the water, via a pressure lock at the bottom of the separator.

Process for the production of polycarbonate agglomerate

The present invention provides a process for the isolation of partially crystalline polycarbonate powder or oligocarbonate powder from solutions thereof, in which process the organic solvent of a polycarbonate solution is vaporized in a heat exchanger, optionally with incorporation of steam, or in a holding tube with incorporation of steam and the pasty mixture of concentrated solution, solvent vapor and optionally water is separated in a separator. In this process, the solvent vapor is condensed in a heat exchanger downstream from the separator. The solvent is vaporized in the heat exchanger by indirect input of heat through the heat exchanger walls and vaporization may be promoted by preheating the polycarbonate or oligocarbonate solution in an upstream heat exchanger or by introducing steam or both.

Process for the isolation of partially crystalline polycarbonate powder

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

This invention relates to a process for producing granulated polymer materials from polymer solutions, in which organic solvent of the polymer solution is evaporated in a heat exchanger, optionally with the admixture of steam, or in a holding tube with the admixture of steam, and the paste-like mixture of concentrated solution, solvent vapour and optionally of condensed steam is separated in a separator provided with rotating built-in components for cleaning off the walls. The pre-concentrated polymer solution is further concentrated in the separator by supplying heat by way of heating the separator walls or the rotating built-in components and by the shearing energy of the rotating built-in components. Residual degassing of the solvent is effected before granulation, e.g. in the discharge extruder of the separator which is provided with rotating built-in components, through one or more degassing zones, optionally by the additional admixture of entraining media, such as inert gas or steam, for example.

Process for producing thermoplastic granulated polymer material from

The invention relates to use of salts of sulphonic acids, phosphonic acids and/or carboxylic acids in combination with halogenated phthalimides for additional processing of glass fibre-containing polycarbonate moulded members.

Use of salts in combination with halogenated phthalimides for flameproof

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Dormagen, Germany

Hugo Obermann