Patent GB-997921-A (GB)
Title: Emulsions of cross-linkable copolymers and process for their preparation
IPC: C08F20/58
Filed: 1963-10-14
Abstract: Aqueous copolymer emulsions having a viscosity of from 30 to 1000 cps, and a copolymer content of from 20 to 60% by weight, comprise a cross-linkable copolymer of (a) one or more vinyl monomers having the formula CH2=CXR in which X is hydrogen, alkyl or halogen and R is hydrogen or an organic radical, e.g. a carboxyl, carboxylic ester or methyl group, (b) from 0.5 to 10% by weight based on the copolymer of an N-methylol derivative of an ethylenically unsaturated amide and (c) from 0.2 to 15% by weight based on the copolymer of a water-soluble salt of an ethylenically unsaturated mono- or di-carboxylic acid.  Specified monomers are (a) alkyl esters of acrylic or methacrylic acid, styrene, vinyltoluene, acrylonitrile and vinyl chloride; (b) N-methylolacrylamide and N-methylol-methacrylamide; (c) water-soluble salts, preferably ammonium or nitrogen-containing organic base salts, of acrylic, methacrylic, itaconic and maleic acids. The copolymer emulsions are prepared by emulsion copolymerization of the monomer components in the presence of from 0.01 to 0.15%, by weight of the total amount of monomers, of a polymerization free radical-producing catalyst.  The catalyst may be a water-soluble salt of persulphuric acid, e.g. ammonium persulphate; Redox systems may also be used.  The emulsifier may be anionic or nonionic or a mixture thereof.  The copolymers are cross-linked by heating and, if desired, in the presence of a cross-linking catalyst, e.g. acids or magnesium, zinc or ammonium salts. The copolymer emulsions are suitable as binders for non-woven fabrics and for finishing leather.  The emulsions may be used alone or in admixture with thermosetting or epoxy resins or aminoplasts, and with paraffins, polyethylene, casein, pigments, fillers and/or thickeners.  An example illustrates the emulsion polymerization of ethyl acrylate, acrylonitrile, N-methylol-acrylamide and acrylic acid together with ammonia solution in the presence of ammonium persulphate catalyst.ALSO:Aqueous copolymer emulsions suitable for finishing leather and having a viscosity of from 30-1000 cPs and a copolymer content of from 20-60% by weight comprise a cross-linkable copolymer of (a) one or more certain vinyl monomers (for a definition thereof see Division C3), (b) from 0.5-10% by weight based on the copolymer of an N-methylol derivative of an ethylenically unsaturated amide and (c) from 0.2-15% by weight based on the copolymer of a water soluble salt of an ethylenically unsaturated mono- or di-carboxylic acid.  The emulsions may be used in admixture with thermosetting or epoxy resins or aminoplasts, and with paraffins, polyethylene, casein, pigments, fillers and/or thickeners. In an example, the emulsion contains a copolymer of ethyl acrylate, acrylonitrile, N-methylolacrylamide and ammonium acrylate and is used in admixture with an inorganic tan pigment dispersed in casein as a primary coat for oxhide which is then heated and plated and finished with a formaldehyde solution.ALSO:Aqueous copolymer emulsions suitable as binders in the formation of non-woven fabrics and having a viscosity of from 30 to 1000 cPs and a copolymer content of from 20 to 60% by weight comprise a cross-linkable copolymer of (a) one or more certain vinyl monomers (for a definition thereof see Division C3), (b) from 0.5 to 10% by weight based on the copolymer of an N-methylol derivative of an ethylenically unsaturated amide and (c) from 0.2 to 15% by weight based on the copolymer of a water soluble salt of an ethylenically unsaturated mono- or di-carboxylic acid. The emulsions may be used in admixture with thermosetting or epoxy resins or aminoplasts, and with paraffins, polyethylene, casein, pigments, fillers and for thickeners.  Many kinds of fibres may be treated with the emulsions, e.g. cotton, rayon, jute, flax, wool, silk, nylon, polyesters, vinyl chloride copolymers, acrylonitrile and glass mat.  Under cross-linking conditions, the fabrics obtained are resistant to solvents, e.g. boiling trichloroethylene.