Wacker-chemie Gmbh

Erwin Lieb

Hubert Wiest

Rudolf Weissgerber

Klaus Hafener

Wilhelm Lechner

Heinz Schafer

Josef Hanzalik

Peter Ludwig

Rainer Berger

A copolymer having good properties for use as a pressure-sensitive adhesive from an aqueous dispersion comprising:

Copolymers for pressure-sensitive adhesives based on acrylic esters,

A process for the manufacture of vinyl chloride copolymers having a reduced content of free vinyl chloride comprising polymerizing a monomer mixture containing from 15% to 90% by weight of vinyl chloride under aqueous emulsion polymerization conditions with conventional post-polymerization, releasing the pressure, flushing the gas space above the copolymer dispersion free of monomer, cooling the copolymer dispersion to a temperature of from 10.degree. to 40.degree. C., adding a redox catalyst to the cooled dispersion consisting of from 0.002% to 0.5% by weight of the dispersion of an oil-soluble peroxy compound, and a water-soluble sulfur-containing reducing agent in a ratio of reducing agent to peroxy compound of 0.5 to 3 equivalents, allowing the dispersion to stand at a temperature of from 10.degree. to 40.degree. C. for a period of two hours to two days and recovering a copolymer dispersion having a vinyl chloride content of less than 50 ppm.

Process for reducing content of free vinyl chloride by posttreating

A hydrolysis-resistant, film-forming, aqueous dispersion of a copolymer consisting essentially of

Hydrolysis-resistant, film-forming copolymer dispersions

A thermally self-cross-linkable ethylene/vinyl acetate copolymer consisting essentially of the following monomer units:

Thermally self-cross-linkable ethylene/vinyl acetate copolymers

A process for the continuous manufacture of an aqueous ethylene/vinyl acetate copolymer dispersion which comprises continuously copolymerizing ethylene and vinyl acetate and optionally other .alpha.-olefinically unsaturated monomers, in an aqueous emulsion in the presence of an emulsifier and/or a protective colloid, and in the presence of a free-radical-forming redox catalyst system of a reducing agent and an oxidizing agent as well, optionally, as a heavy metal salt, and recovering said ethylene/vinyl acetate copolymer dispersion, characterized by (a) the presence of a molar excess of at least 3 times, preferably from 3 to 10 times, said reducing agent over said oxidizing agent dosed into the reaction medium and (b) adding the monomers continuously to the reaction mixture at such a rate that the concentration of unreacted monomers at no place in the reaction zone exceeds 15% by weight of the total weight of the reaction mixture.

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Burghausen, Germany

Erwin Lieb