Wacker-chemie Gmbh

Klaus Hafener

Herbert Eck

Hubert Wiest

Peter Ball

Klaus Marquardt

Manfred Selig

Klaus Adler

Erwin Lieb

Peter Ludwig

Aqueous copolymer dispersions suitable for use in the manufacture of adhesives or as binding agents or as coating substances are produced by the emulsion polymerization of from 1 to 50% by weight of ethylene and from 99 to 50% by weight of vinyl monomers. With the process of the invention, in which, as vinyl monomers, vinyl chloride and, if desired, other ethylenically-unsaturated monomers, for example esters, are used, a higher ethylene content in the copolymer can be obtained at a lower pressure than hitherto. For this purpose, the greater part of the vinyl monomers is metered in and, in addition, an inert organic substance is used.

Process for the manufacture of aqueous copolymer dispersions and their

Stabilized aqueous dispersions of vinyl chloride polymer having at least 25% by weight of vinyl chloride units in the polymer and having K values of between 20 and 80, having added as a stabilizing agent 0.3-6% by weight of substances selected from the group of compounds according to the general formula ##STR1## wherein n has the meaning of from 0 to 2 or water-soluble salts thereof. The invention also relates to a process of producing the stabilized products by adding the stabilizing agent after polymerization in aqueous dispersion, and to the use of the stabilized dispersions in binders, coating compositions, paints, adhesives, textile auxiliaries and paper-coating compositions.

Stabilized aqueous dispersions of vinyl chloride polymers

Aqueous ethylene/vinyl chloride/vinyl alkanoate and/or alkyl acrylate copolymer dispersions having a non-uniform particle size distribution, in which one particle size distribution maximum is at 0.03 to 0.2.mu. and a second maximum is at 0.15 to 1.mu. and in which 5% to 60% by weight of the particles belong to the amount of particles having said second maximum, which are produced by free-radical polymerization at 0.degree. to 90.degree. C., while stirring, in the presence of emulsifiers which, in amounts of 0.5% to 15% by weight, calculated on the final solid resin, are not added until a polymerization conversion of 1% to 60% by weight of the total amount of monomer has been reached. The copolymer dispersions have solids contents of 20% to 70% by weight of copolymer comprising 20% to 92% by weight of vinyl chloride, 5% to 60% by weight of ethylene and 3% to 75% by weight of vinyl esters and/or acrylic acid esters, and, optionally, up to 15% by weight of other monomers copolymerizable with ethylene and vinyl chloride, said monomers being metered into the polymerization mixture together with the emulsifiers during the manufacturing process.

Process for the manufacture of aqueous ethylene/vinyl chloride/vinyl

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.

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Burghausen, Germany

Klaus Hafener