Abstract: A method of producing ABS moulding compositions wherein a solution of polymers in group (A) solvents is gradually supplied to a polymerizing mixture of previously-formed soluble rubber, aromatic mono-alkenyl compounds, ethylenically unsaturated nitrites, optional other copolymerizable compounds and optionally a group (B) solvent or a mixture of group (A) and group (B) solvents, the gradual addition of the polymer solution to the polymerizing mixture being started before the beginning of phase inversion and at a monomer conversion rate of 5 to 15% and a viscosity of the polymerizing mixture of less than 20 Pa.sec with simultaneous continuation of polymerization, the group (A) solvent is an aliphatic (C.sub.1 -C.sub.8) or cycloaliphatic alcohol, ketone, ether, ester and/or nitrile, and the group (B) solvent is an aliphatic (C.sub.4 -C.sub.10), cycloaliphatic and/or aromatic hydrocarbon.

Abstract: The invention relates to a process for the purification of p,p-bisphenolate solutions such as are obtained in the production of bisphenolates from soda lye and bisphenols by extraction.

Abstract: The transportation and storage of phenol is enhanced by additions of up to 70% by weight of acetone to liquid phenol.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The invention relates to a process for the synthesis of bis-(4-hydroxyphenyl)-alkanes on ion-exchange resins or mixtures of ion-exchange resins which are modified with alkyl-SH groups, wherein the monophenols and carbonyl compounds to be used have first been purified to remove substances which can transfer alkyl groups.

Abstract: The invention relates to the preparation of a transparent crystalline adduct consisting of bisphenol A (75 parts) and bisphenol TMC (25 parts), which has a melting point of 144.degree. C. which is below the melting points of the pure starting compounds bisphenol A (157.degree. C.) and bisphenol TMC (208.degree. C.).

Abstract: The present invention relates to the use of cyclic carbonates as demoulding agents for thermoplastic polycarbonates, and to the incorporation of these cyclic carbonates into the thermoplastic polycarbonates.

Abstract: The invention relates to a method for recycling (reprocessing) aqueous extract solutions obtained in the production of polyamides. The method for reprocessing the aqueous extract solutions obtained consists in that the aqueous extract solution is concentrated and polymerised, adding small amounts of dicarboxylic acid or polycarboxylic acid to the extract solution.

Abstract: The invention relates to the synthesis of bisphenols from monophenols and carbonyl compounds such as aldehydes and ketones with concentrated mineral acids such as hydrochloric acid and/or hydrogen chloride gas as acid catalysts and a mercaptan as cocatalyst, which is fixed by an ion-pair bond to a matrix insoluble in the reaction medium.

Abstract: 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.

Abstract: 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.

Abstract: The present invention provides a two-stage melt process for the manufacture of thermoplastic, solvent-free, low-branched polycarbonates with low OH end-group contents with the use of ammonium or phophonium catalysts in the first stage and alkali and alkaline earth catalysts in the second stage.

Abstract: The present invention relates to thermoplastic aromatic polycarbonates having a content of special aryl phosphines, to their preparation, and to their use in the light engineering sector and in optics.

Abstract: The present invention provides a process for the production of high purity bisphenol A by special in-process-crystallisation of bisphenol A/phenol adduct crystallisates.

Abstract: Process for pretreating abietic acid derivatives comprising dissolving an abietic derivative in water to form a 2 to 25% by weight solution, adding a base so that the pH of the solution is from 10 to 14 and removing from 0.5 to 25% by weight of the abietic acid derivative originally present in the solution by extraction or steam distillation while maintaining the pH from 10 to 14.

Abstract: The invention relates to repeatedly regeneratable ion exchanger resins with a thin covering of alkyl-SH groups.

Abstract: The invention relates to a process for the production of polycarbonates by the two-phase interfacial method in which deviations between measured and estimated variables are continuously minimized by means of a suitably selected observer or filter system on the basis of a process model with an empirical Mark-Houwink relation adapted to the process. The variables estimated by the observer/filter are converted into control variables which are used to set input streams of the production process. Product quality is kept constant, changes in load or set values are quickly intercepted and even disturbances not readily accessible to measurement are taken into account by the process control.

Abstract: The invention relates to a process for increasing (improving) the volume/time yield of fixed-bed reactors in the production of bisphenol A.