Abstract: This invention relates to a simplified process for the preparation of polyarylene sulphides with improved product quality from alkali metal sulphides and dihalogenated aromatic compounds, in which the alkali metal sulphides are prepared and reacted in situ.

Abstract: This invention relates to a process for the purification of optionally branched polyarylene sulphides (PPS). Polyarylene sulphides which have been purified according to the invention are distinguished by the reduced amount of ash-forming impurities contained in them.

Abstract: 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.

Abstract: A three-step process for the production of solventless polycarbonate is disclosed. Accordingly, a mixture of two different oligocarbonates each prepared by the interfacial method, is prepared in the first process step. In a second step, the mixture is crystallized. The third step entails polycondensation. In an additional embodiment of the invention the first step uses a mixture of one oligocarbonate with a suitable monomer.

Abstract: The invention concerns a process for the manufcture of polyarylene sulphides from alkali sulphide and aromatic dihalogen compounds, whereby the alkali sulphide is produced in situ.

Abstract: The invention relates to a process for the production of high molecular weight, optionally branched polyarylene sulfides having a low content of organically bound halogen. They are prepared by reaction of alkali sulfides and/or alkali hydrogen sulfides with aromatic dihalogen compounds in a polar organic solvent.

Abstract: The liquid crystal polycondensates according to the invention based on aromatic hydroxycarboxylic acids, if appropriate aromatic aminocarboxylic acids, diphenols, if appropriate aminophenols, aromatic dicarboxylic acids and if appropriate carbonic acid which are obtainable by polycondensation of the difunctional monomers mentioned in the melt in the presence of aromatic esters with a defined sequence of the structural units of the formula ##STR1## of oligomers with random distribution of the structural units of the formula ##STR2## have a good heat stability and exhibit a stable viscosity under the processing conditions. The liquid crystal polycondensates can be used for the production of shaped articles, films, fibers and filaments.

Abstract: Aromatic polyesters are prepared by the transesterification of aromatic dicarboxylic acid dialkyl esters with diester derivatives of divalent phenols at temperatures of about 260.degree. to 350.degree. C. with removal of the resulting monocarboxylic acid alkyl ester from the reaction mixture.

Abstract: This invention relates to a process for the preparation of crystalline polyarylenesulphides. Polyarylenesulphides with a high degree of purity, low electrolyte content and low non-uniformity are obtained. The polyarylenesulphides obtained have improved mechanical and electrical properties.

Abstract: The invention relates to a process for purifying and isolating polyarylene sulphides. In this process polyarylene sulphides are obtained with a particularly low electrolyte content.

Abstract: This invention relates to a process for the preparation of N-alkylated caprolactams by the cyclization of N-alkylated caproic acids.

Abstract: The invention relates to polyarylene sulphides with melt viscosities settable to defined values. The products are distinguished by high stability of the melt. They are obtained by adding, in the preparation of these polyarylene sulphides, certain phenols as chain terminators to the reaction mixture.

Abstract: Process for the preparation of copolyamides from adipic acid, terephthalic acid and hexamethylene diamine containing 25-48% by weight of units of hexamethylene terephthalamide, by precondensing the monomers at a temperature of at least 250.degree. C. and a pressure of at least 35 bar and completing the polycondensation in the usual manner.

Abstract: The present invention is related to polycarbonate molding compositions containing a co-precipitate of a polycarbonate resin and a fluoropolymer. This co-precipitate was found to be suitable as an additive for polycarbonate resins because it offers improved dispersibility with the resin and good flammability performance as well as aesthetic characteristics. The co-precipitate is prepared by first mixing an aqueous dispersion of a fluoropolymer with a polycarbonate solution and then precipitating both using a suitable precipitation agent. After isolation washing and drying the co-precipitate of the invention is suitable for incorporation in a polycarbonate resin optionally with known flame retarding agents. Molded parts prepared from the compositions of the invention are characterized by their improved homogeneity and flame retardance.

Abstract: The invention relates to a process for the isolation of polyarylene sulphides, polyarylene sulphides with particularly low electrolyte content being obtained.

Abstract: This invention relates to optionally branched polyarylene sulphides and a process for the production thereof in a polar solvent, from 0.2 to 100 mole %, based on the aromatic dihalogen compounds, of an amino acid being added to the reaction mixture.

Abstract: This invention relates to optionally branched polyarylene sulphides and a process for the production thereof in a polar solvent, from 0.2 to 100 mole %, based on the aromatic dihalogen compounds, of an amino acid being added to the reaction mixture.

Abstract: The isolation of polyarylene sulphides by freeing polyarylene sulphides of the type obtained in customary production processes from adherent water and any other volatile constituents by treating the polyarylene sulphides in screw machines and optionally melting them either simultaneously or subsequently.

Abstract: A process for the production of polyamides by the polycondensation of aqueous solutions of salts of diamines and dicarboxylic acids by continuously introducing the aqueous salt solution into a precondensate melt under atmospheric pressure and simultaneously distilling off the water and maintaining the temperature of the melt at a minimum temperature of 180.degree. C.

Abstract: The present invention relates to a process for the preparation of aromatic polycarbonates from diphenols by the phase boundary process, which is characterized in that cyclic, preferably monocyclic or bicyclic, aza compounds are used as catalysts. The present invention also relates to the polycarbonates obtainable according to the process, which are distinguished by high light transmission and a low tendency to yellowing, even after relatively severe exposure to heat.