Wacker-Chemie Gmbh

Gerhard Brink

Konrad Alfons Wierer

Konran A Wierer

A product is obtained by a process involving binding two or more layers of tissue fabrics derived from cellular pulp or cellulose fiber. In this process, a binder composition comprised of: (a) 10 to 80 parts by weight of an aqueous plastics dispersion of a solids content of 30 to 70% by weight and based on one or more copolymers comprising vinyl acetate/ethylene copolymers, vinyl acetate/ethylene/N-methylol(meth)acrylamide terpolymers, alkyl acrylate/N-methylol(meth)acrylamide copolymers and vinyl acetate/ethylene/alkyl acrylate copolymers, or vinyl acetate/alkyl acrylate copolymers, which optionally have a N-methylol (meth)acrylamide content, (b) 50 to 300 parts by weight of a filler which has an average particle size of 0.5 to 100 .mu.m, and (c) 0 to 4 parts by weight of a thickener and/or at least 0.1 parts by weight of a dispersing agent to a portion of a single layer of tissue, affixing a further single layer of tissue and drying to obtain a prelaminate. (2) An additional binder composition is applied to this prelaminate thereby affixing a further single layer of tissue, and drying. Optionally, step (2) can be repeated one or more times.

Aqueous binder composition

The invention relates to aqueous dispersions of plastics having a solids content of 30 to 70% by weight and a reduced formaldehyde content, based on polymers of one or more monomers from the group comprising acrylic acid esters, methacrylic acid esters, vinyl esters, olefins, vinyl halides, vinylaromatics and ethylenically unsaturated carboxylic acids and amides thereof, and a content of 0 to 10% by weight, based on the total weight of the polymer, of N-alkylamides and/or N-alkoxyalkylamides of ethylenically unsaturated carboxylic acids, wherein the dispersion contains 0.05 to 10% by weight, based on the polymer, of one or more peroxy compounds from the group comprising hydrogen peroxide, organic peroxides, perborates, percarbonates, persulfates and perphosphates. The dispersions of plastics modified according to the invention are suitable for use as binders, coating agents, impregnating agents and adhesives in all fields in which a low formaldehyde content or a reduced release of formaldehyde during processing is required.

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Burghausen, Germany

Gerhard Brink