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: Apparatus for carrying out mass transfer processes with high-viscosity liquids comprising a vertically arranged vessel (1) having a feeder (4) for the liquid to be treated, an outlet (7) for volatile components and an outlet (6) for the treated liquid, the feeder means (4) being equipped with a distributor element (3) having a multiplicity of orifices (8, 10) for subdividing the high-viscosity liquid to be treated into a multiplicity of individual streams, wherein essentially vertically arranged wire loops (2) are disposed in the vicinity of the orifices (8, 10), along which wire loops the high-viscosity liquid runs off under the action of gravity.

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 process for producing a polyamide or copolyamide freed from volatile constituents by removing the volatile constituents, in particular the monomers and dimers, in at least two stages from the polymer melt by using an, in particular, gaseous entrainer is described. The invention also relates to polyamide compositions made of polyamide 6 or a copolyamide with a reduced volatile constituent content, as well as moulding compositions made of the above-mentioned polyamides, and moulded articles and fibers which are produced from these moulding compositions.

Abstract: A process for producing a polyamide or copolyamide freed from volatile constituents by removing the volatile constituents, in particular the monomers and dimers, in at least two stages from the polymer melt by using an, in particular, gaseous entrainer is described. The invention also relates to polyamide compositions made of polyamide 6 or a copolyamide with a reduced volatile constituent content, as well as moulding compositions made of the above-mentioned polyamides, and moulded articles and fibres which are produced from these moulding compositions.

Abstract: An apparatus for carrying out mass transfer processes with high-viscosity liquids is described, particularly for boiling down and/or devolatilizing polymer melts, comprising at least a vertically arranged vessel (1) having a feeder means (4) for the liquid to be treated, an outlet (7) for volatile components and an outlet (6) for the treated liquid, the feeder means (4) being equipped with a distributor element (3) having a multiplicity of orifices (8, 10) for subdividing the high-viscosity liquid to be treated into a multiplicity of individual streams, characterized in that essentially vertically arranged wire loops (2) are disposed in the vicinity of the orifices (8, 10), along which wire loops the high-viscosity liquid runs off under the action of gravity.

Abstract: A tread profile for winter tires of motor vehicles, in particular vehicles of the pickup truck or light truck class, includes at least four circumferentially extending longitudinal grooves and transverse grooves demarcating profile blocks. The transverse grooves extend helically with an approximately Z-shaped kink in the middle of the width of the tread. The longitudinal grooves have a given groove width and have individual segments between two of the transverse grooves. Each of the segments are staggered alternatingly to the left and to the right relative to one another by at least one-half of the given groove width.