Wacker-chemie Gmbh

Gerhard Beier

Johann Bauer

Klaus Adler

Thomas Balwe

Alex Sabel

Heinz Hefner

Helmut E Thyret

An improvement in the process of producing polyvinyl chloride by the suspension process in the presence of protective colloids by utilizing a protective colloid mixture of from 20% to 80% of the protective colloid mixture of a polyvinyl acetate having a hydrolysis degree of 40 to 55 mol % and the remainder of the protective colloid mixture of (1) a water-soluble polyvinyl alcohol having a hydrolysis degree of 70 to 90 mol %, or (2) an aminoethyl-hydroxypropyl cellulose having a molar substitution of from 0.05 to 1.5 mols of aminoethyl groups and 3 to 5 mols of hydroxypropyl groups, or (3) a vinyl acetate/vinyl pyrrolidone copolymer having a ratio of vinyl pyrrolidone to vinyl acetate in the copolymer of 50% to 70% by weight to 30% to 50% by weight and a K-value of 25 to 40. By the use of this protective colloid mixture, the polyvinyl chloride produced exhibits a large absorption of plasticizer and gives finished products having a low number of specks.

Process for suspension polymerization of vinyl chloride employing mixed

A process for the production of polyvinyl chloride graft copolymers from ethylene/vinyl acetate copolymers and vinyl chloride by graft polymerization in the aqueous phase consisting essentially of adding a water-soluble, free-radical-forming polymerization catalyst to an aqueous dispersion of an ethylene/vinyl acetate copolymer optionally containing additional emulsifiers and/or dispersion stabilizers, heating said dispersion to the polymerization temperature, adding vinyl chloride gas above said agitated heated dispersion at such rate that the pressure is below the saturation pressure of vinyl chloride at the polymerization temperature, and recovering said polyvinyl chloride grafted copolymer.

Process for the production of polyvinyl chloride graft copolymers

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Burghausen, Germany

Gerhard Beier