Wacker-chemie Gmbh

Hubert Wiest

Erwin Lieb

Klaus Hafener

Wilhelm Lechner

Herbert Eck

Klaus Marquardt

Rudolf Weissgerber

Hartmut Brabetz

Dieter Gorzel

Heinz Schafer

Josef Hanzalik

Peter Ludwig

Rainer Berger

The invention relates to a process for the preparation of polymers from polymerizable urethanes prepared by reacting isocyanates having at least two isocyanato groups with polyesters of the formula ##STR1## wherein R is alkylene having from 2 to 10 carbon atoms, A is an ethylenically-unsaturated radical, and n is an integer of from 1 to 100.

Process for the preparation of polymers containing urethane groups

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,

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.

Process for reducing content of free vinyl chloride by posttreating

Ester copolymers cross-linkable under acid, alkaline and heated conditions consisting essentially of a copolymerizate with from 75% to 99% by weight of vinyl and/or acrylic ester monomer units, from 0.2% to 15% by weight of olefinically-unsaturated halotriazine monomer units, from 0.2% to 10% by weight of mono-olefinically unsaturated monomer units containing free or protected N-methylol groups and, optionally, up to 10% by weight of other monomer units copolymerizable with ester monomer units.

Ester copolymers cross-linkable under acid and alkaline conditions

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.

Process for the continuous production of an ethylene/vinyl acetate

An improvement in the production of polyvinyl ester dispersions by polymerization of vinyl esters or copolymerization of vinyl esters with up to 40% by weight of oil-soluble, mono-olefinically-unsaturated monomers in an aqueous emulsion in the presence of water-soluble radical-forming polymerization catalysts, protective colloids and optionally emulsifiers and polymerization aids, the improvement comprising using carboxymethyl celluloses having a substitution degree of at least 10 as said protective colloids; as well as stable mixtures of the said polyvinyl ester dispersions and dextrin.

Growing community of inventors

Burghausen, Germany

Hubert Wiest