Wacker-chemie Gmbh

Willi Kleine

Werner Frey

Manfred Heisler

Ingo Haller

Ernst Spindler

Albrecht Daweritz

A matting agent for plastic compositions comprising either a high molecular weight, gel-containing vinyl chloride polymer with a gel content of 10 to 99% by weight, a maximum mercury porosity of 0.2 cm.sup.3 /g, a maximum plasticizer absorption of 15%, a particle size parameter d' of 10 to 80 .mu.m and a coefficient of uniformity n greater than 3, or a high molecular weight, gel containing copolymer of vinyl chloride and 1 to 40% by weight of comonomer with a gel content of 10 to 99% by weight, a maximum mercury porosity of 0.10 cm.sup.3 /g, a maximum plasticizer absorption of 10%, a particle size parameter d' of 10 to 80 .mu.m and a coefficient of uniformity n greater than 3, plastic articles containing said matting agent and a method of imparting a matt to the surface of plastic articles.

Novel matting agent and its use

In a process of polymerizing ethylenically unsaturated compounds by polymerization of ethylenically unsaturated monomers in the presence of a free radical-forming initiator system and customary protective colloids and/or emulsifiers and optional known additives in a reactor whose surfaces contact the reaction components, the improvement comprising providing the reactor surfaces with a coating that at least suppresses polymer deposit formation without effecting the color and quality of the polymer.

Polymerization reactor provided with coating that suppresses polymer

In a process of polymerizing ethylenically unsaturated compounds by polymerization of ethylenically unsaturated monomers in the presence of a free radical-forming initiator system and optionally customary protective colloids and/or emulsifiers and optional known additives in a reactor whose surfaces contact the reaction components, the improvement comprising providing the reactor surfaces with a coating that at least suppresses polymer deposit formation without effecting the color and quality of the polymer.

Method of inhibiting polymer deposition on reactor walls during

An improvement in the process for the polymerization of vinyl halide polymers comprising polymerizing at least one vinyl halide and, optionally, other olefinically-unsaturated monomers copolymerizable with vinyl halides, in an aqueous dispersion in the presence of free-radical-forming polymerization initiators, dispersants and, optionally, other additives in the presence of an inhibitor of polymer deposits and recovering said vinyl halide polymers, the improvement consisting essentially of adding to the reaction mixture from 10 to 1,000 ppm, based on the monomers, of at least one carbonyl compound having the formula: ##STR1## wherein R.sup.1 is selected from the group consisting of hydrogen and a hydrocarbon having from 1 to 9 carbon atoms selected from the group consisting of alkyl, aryl, alkaryl and aralkyl; R.sup.2 represents an oxyhydrocarbon having from 1 to 9 carbon atoms selected from the group consisting of alkoxy, aryloxy, alkaryloxy and aralkoxy, and a hydrocarbon having from 1 to 9 carbon atoms selected from the group consisting of alkyl, aryl, alkaryl and aralkyl; X is selected from the group consisting of hydroxy and R.sup.3 --CO--, wherein R.sup.3 represents a hydrocarbon having from 1 to 9 carbon atoms selected from the group consisting of alkyl, aryl, alkaryl and aralkyl; as said inhibitor of polymer deposits.

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Burghausen, Germany

Willi Kleine