GB1011809A - Binder and process for flocking surfaces - Google Patents

Abstract

Binders for flocking surfaces comprise, for each 100 parts by weight: (a) 20 to 45 parts by weight of one or more copolymers prepared by polymerization in an aqueous dispersion at a maximum pH value of 5 of a mixture of monomers consisting of: (i) 40-80% by weight of one or more C2-C4 acrylates and/or methacrylates, (ii) 10-35% by weight of acrylonitrile and/or methacrylonitrile, (iii) 3-6% by weight of N-methylol acrylamide and/or methacrylamide, (iv) 0.5-5% by weight of a polymerizable carboxylic acid, and (v) 0-40% by weight of one or more other unsaturated compounds, the copolymer being thickened by the addition of an alkaline substance; (b) 3 to 30 parts by weight of a water-soluble or -dispersible aminoplast-forming substance containing N-methyl or N-methylol ether groups; (c) 0.1-5 parts of at least one acidic condensation catalyst; and, optionally, (d) conventional amounts of one or more conventional flock binder additives, the excess above the total quantity included in (a)-(d) needed to give a total of 100 parts by weight representing the quantity of water present in the aqueous dispersion. The examples describe compositions in which there are used as components (a) ammonia - neutralized aqueous dispersions of n - butyl acrylate/ethyl acrylate/acrylonitrile/N - methylolmethacrylamide/acrylic acid, isobutyl acrylate/acrylonitrile/N - methylolacrylamide/methacryli acid, and n-butyl acrylate/acrylonitrile/styrene/N - methylolmethacryl amide/acrylic acid copolymers, as components (b) dimethylolurea dimethyl ether and the dimethylol compound of butanedioldiurethane, as components (c) ammonium nitrate and thiocyanate, and as components (d) a sperm oil alcohol/ethylene oxide condensate and the sodium salt of the acid sulphate thereof, cellulose methyl ether, dioctyl phthalate, urea, an azo dyestuff, and kerosene. The compositions are cross-linked, after a flocking operation, by heating at temperatures above 90 DEG C.ALSO:Flocked surfaces are produced by applying fibrous flock to the surface of a porous material on which has been deposited a binder comprising, in an aqueous medium, (a) a copolymer of (i) one or more C2-C4 acrylates and/or methacrylates, (ii) acrylonitrile and/or methacrylonitrile, (iii) N-methylol acrylamide and/or methacrylamide, (iv) an unsaturated carboxylic acid, and, optionally, (v) one or more other unsaturated compounds, (b) a water-soluble or -dispersible aminoplast-forming substance containing N-methylo or N-methylol ether groups, (c) an acidic condensation catalyst, and, optionally, (d) conventional flock binder additives (see Division C3). The examples describe flocking the surfaces of jute and cotton fabrics with nylon-6 fibres, and surfaces of polyamide, polyester, viscose rayon and cellulose acetate fabrics with viscose rayon fibres, the fabric surfaces being printed with compositions in which there are used as components (a) ammonia-neutralized aqueous dispersions of n-butyl acrylate/ethyl acrylate/acrylonitrile/N-methylolmethacrylamide/acrylic acid, isobutyl acrylate / acrylonitrile / N-methylolacrylamide/methacrylic acid, and n-butyl acrylate/acrylonitrile/styrene/N-methylolacrylamide/acrylic acid copolymers, as components (b) dimethylol urea dimethyl ether and the dimethylol compound of butanedioldiurethane, as components (c) ammonium nitrate and thiocyanate, and as components (d) a sperm oil alcohol/ethylene oxide condensate and the sodium salt of the acid sulphate thereof, cellulose methyl ether, dioctyl phthalate, urea, an azo dyestuff and kerosene. After flocking, the binders are cross-linked by heating to temperatures above 90 DEG C.