Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.