Wacker-chemie Gmbh

Peter Ludwig

Hubert Wiest

Erwin Lieb

Klaus Hafener

Peter Pietschmann

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 process for the production of a copolymer from at least one monomer which is gaseous under the polymerization conditions and at least one monomer that is liquid under the polymerization conditions by copolymerizing the same discontinuously in an aqueous media employing a polymerization vessel under conditions whereby a gas space is required, said gas space being provided by a second vessel connected to the polymerization vessel through a closeable connection, whereby on completion of polymerization, the closeable connection is closed in order to retain the gaseous monomer under pressure.

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Burghausen, Germany

Peter Ludwig