Abstract: A continuous process for the production of an elastomer-modified thermoplastic is disclosed. The process entails (i) obtaining graft elastomer (D) having residual moisture content of 1 to 50 wt. %, particularly 5 to 50 wt. %, particularly preferably 10 to 40 wt. %, (ii) introducing (D) and thermoplastic resin (B) through an inlet to a reactor operating under conditions calculated to melt (D) and (B) and to remove organic volatile components C) to produce a molten blend, the reactor being equipped with a plurality of kneading bars, that convey a portion of the molten blend towards the reactor inlet.

Abstract: Rubber-free copolymers of unsaturated monomers selected from the group comprising styrenes and vinyl cyanides are disclosed. The copolymers that contain 65 to 80 wt. %, of styrene and 20 to 35 wt. % of acrylonitrile are characterized in their low content of residual monomers and improved physical properties. Also disclosed are a process and a device for the preparation of these copolymers.

Abstract: Homo- and/or copolymers of one or more ethylenically unsaturated monomers, suitable for the preparation of molded articles that feature improved properties, especially improved fracture properties, heat stability and notched impact strength are disclosed. These homo- and/or copolymers are characterized in that they contain less than 400 particles per m2 of surface area with a diameter greater than 200 ?m.

Abstract: A continuous process for the production of an elastomer-modified thermoplastic is disclosed. The process entails (i) obtaining graft elastomer (D) having residual moisture content of 1 to 50 wt. %, particularly 5 to 50 wt. %, particularly preferably 10 to 40 wt. %, (ii) introducing (D) and thermoplastic resin (B) through an inlet to a reactor operating under conditions calculated to melt (D) and (B) and to remove organic volatile components C) to produce a molten blend, the reactor being equipped with a plurality of kneading bars, that convey a portion of the molten blend towards the reactor inlet.

Abstract: The invention relates to homopolymers and/or copolymers containing <100 ppm coarse particles with a particle diameter of between 200 and 500 &mgr;m, to thermoplastic moulding materials containing said homopolymtrs and/or copolymers, to the use of the homopolymers and/or copolymers and moulding materials for the production of moulded parts and to the moulded parts themselves.

Abstract: Rubber-free copolymers of unsaturated monomers selected from the group comprising styrenes and vinyl cyanides containing 65 wt. % to 80 wt. %, preferably 68 wt. % to 77 wt. % of styrene and 20 wt. % to 35 wt. %, preferably 23 wt. % to 32 wt. % of acrylonitrile, and a process and a device for the preparation thereof are set out and described. As a result of a gentle, two-stage evaporative treatment, the copolymers have a low residual monomer content, namely less than 20 ppm, preferably 10 ppm of acrylonitrile and less than 200 ppm, preferably 100 ppm of styrene and less than 200 ppm, preferably 100 ppm of ethyl benzene. To this end, solutions of the product are brought to concentrations greater than/equal to 99.8% in a first step of gentle concentration by introducing energy with simultaneous evaporation, and further monomers are removed in a second step without intermediate heating.

Abstract: A method for producing bisphenol A in prill form is disclosed. Molten bisphenol is top-fed into a prilling tower via a plate containing a plurality of nozzles. A gas coolant guided through a circuit is led into said tower in a counter flow direction. The prills are cooled to about room temperature, collected at the bottom of the tower and removed. Also disclosed is the device for carrying out the inventive method and the prills thus produced.

Abstract: The invention relates to homo- and copolymers that contain less than 400 particles with >200 &mgr;m per m2 surface, to thermoplastic molding compounds that contain said homo- and/or copolymers and to the use of the homo- and/or copolymers and of the molding compounds for producing molded bodies. The invention further relates to the molded bodies themselves and to a method for producing the homo- and/or copolymers.

Abstract: The present invention relates to a process for the manufacture of bis(4-hydroxyaryl)alkanes by heterogeneous acid-catalyzed reaction of aromatic hydroxy compounds with ketones in reactors connected in series, which in the direction of advancing conversion are operated with rising temperature and optionally with increasing loading.

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 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 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: 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 increasing (improving) the volume/time yield of fixed-bed reactors in the production of bisphenol A.

Abstract: The invention relates to a process for the production of bisphenols from acetone and phenols in the presence of sulfonic acid ion exchanger resins modified with alkyl-SH groups, in which 0.6 to 5% by weight H.sub.2 O is added to the mixture of phenol and acetone before the reaction.

Abstract: The invention relates to a special process for the production of high-purity bisphenol A from acetone and phenol in the presence of acidic catalysts.

Abstract: This invention relates to a process for the preparation of substituted cycloalkylidene bisphenols from phenols and special cycloalkanones in the presence of acid condensation catalysts and in the presence of water.

Abstract: The instant invention is directed to a continuous process for the production of thermoplastic materials, comprising:I. introducing 4 to 65 parts by weight of thermoplastic polymer into an extruder at a first inlet, wherein the temperature within said extruder is such that said thermoplastic polymer melts;II. adding to said thermoplastic polymer through a second inlet 35 to 96 parts by weight of the following polyurethane forming components, such that the total parts by weight of thermoplastic polymer and polyurethane components is 100:(A) organic polyisocyanate; and(B) chain lengthening agent with a molecular weight below 400 containing a hydroxyl group and/or amine group;wherein the ratio of isocyanate groups of component (A) to Zerewitinoff active groups of component (B) is in the range of from 0.90:1 to 1.2:1; andIII. discharging from the extruder the product of the process when the reaction of said polyurethane components (A) and (B) is substantially complete.

Abstract: The instant invention is directed to a process for the modification of a thermoplastic polymer comprising:I. introducing 70 to 98 parts by weight of thermoplastic polymer into an extruder at a first inlet;II. adding to said thermoplastic polymer through a second inlet 2 to 30 parts by weight of the following polyurethane forming components, such that the total parts by weight of the thermoplastic polymer and polyurethane components is 100:(A) organic polyisocyanate; and(B) chain lengthening agent with a molecular weight below 400 containing at least one hydroxyl group and/or amino group;wherein the ratio of isocyanate groups of component (A) to Zerewitinoff active groups of component (B) is in the range of from 0.90:1 to 1.2:1; andIII. discharging from the extruder the product of the process.