Abstract: A process of evaporating a viscous polymer solution is described. The process includes: (a) providing a viscous polymer solution including at least 30 wt. % of solvents and monomers; (b) introducing the viscous polymer solution into a heated helix (5), the heated helix having a vapor exit velocity of 200 to 300 m/s, (a film flow including a two-phase mixture of polymer melt, and solvent vapors and monomer vapors being formed within the helix); (c) forwarding the film flow from helix (5) into a heated vapor separator (6); (d) expanding the two-phase mixture of polymer melt, and solvent vapors and monomer vapors of the film flow within vapor separator (6) at an absolute pressure of 10 mbar to 800 mbar, (a bottom product including a concentrated melt of the polymer is formed within the vapor separator); and (e) withdrawing the bottom product from vapor separator (6).

Abstract: A method for removing volatile components from polymer solutions is disclosed. The method, yielding products having low content of residual volatile components and causing no thermal damage to the polymer, entails using apparatuses in which surfaces which come into contact with the product are made from materials which are low in iron content.

Abstract: A process for the production of polycarbonate is disclosed. The process, representing an improvement over the known interfacial polycondensation process entails introducing into the loop of a circulating reactor that additionally contains, a residence tank, an optional mixer, a pump, and a heat exchanger (i) an organic phase that contains a solvent for polycarbonate and phosgene and (ii) an aqueous phase that contains an aqueous lye solution, a dihydroxy compound and an optional monophenol to form an emulsion. Maintaining specified temperature and process conditions results in polycarbonate resin having good properties and in waste water that are characterized by their purity.

Abstract: The production of polycarbonate by the phase boundary method is disclosed. In accordance with the inventive process, a solution that contains polycarbonate is repeatedly washed with a washing liquid and the washing liquid is separated from the solution that contains the polycarbonate by separating elements and the solvent is then evaporated. The process is characterized in that the organic solution that contains the polycarbonate and the washing liquid are separated from each other after the first washing stage in a coalescer that contains hydrophilic packing.

Abstract: Nitrate-containing (contaminated) solutions are reduced with SO2 gas in the presence of an at least equimolar amount of NH4+ or ammonium salt.

Abstract: A process for making a shaped product from thermoplastic polycarbonate is disclosed. The process comprises producing polycarbonate melt by a method selected from the group consisting of phase interface and melt transesterification and introducing the melt directly into a forming apparatus to form a shaped product. The forming apparatus is selected from the group consisting of an injection molding machine and an extruder. The process is characterized in the absence therefrom of polycarbonate in granular form.

Abstract: 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.

Abstract: 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.

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 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.

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

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.