Patent GB-950153-A (GB)
Title: Film-forming copolymers from acrylates, acrylic acid and n-methylolmethacrylamide
Inventor: WILHELM HANS
IPC: C08F20/58
Filed: 1962-05-23
Abstract: Copolymers of 60 to 96.5% by weight of an acrylic ester of a C1- 8 alkanol, 3 to 30% by weight of acrylic acid and 0.5 to 10% by weight of N-methylol methacrylamide may be prepared by copolymerizing the monomers in aqueous media in the presence of polymerization catalysts and emulsifying agents at a pH of less than 5.5. Preferred esters are those of C2- 4 alkanols, particularly ethyl acrylate.  Specified catalysts are potassium and ammonium persulphates, and specified emulsifiers are fatty acid salts, salts of alkyl sulphonic acids and alkyl sulphates and the sulphates of polyoxyalkylene derivatives of alcohols, acids, amides, imides and particularly phenols.  Minor amounts of additional comonomers, e.g. methacrylic, itaconic, maleic and fumaric acids and esters, acrylonitrile, vinyl esters, vinyl and vinylidene chlorides, N-methylolacrylamide, N-methylolmaleinimide and N-methylolacryloylurea may also be present.  The copolymer dispersions may be compounded with conventional ingredients and the resulting compositions used for finishing leather and textile materials.  Examples describe dispersions of copolymers of acrylic and N-methylol methacrylamide with (1) ethyl acrylate compounded with casein and iron oxide; (2) isobutyl acrylate and acrylonitrile compounded with casein and lead chromate; (3) n-butyl acrylate; (4) n-butyl acrylate compounded with colloidal silicic acid, isooctylphenol/ethylene oxide condensate and ammonium nitrate; (5) ethyl acrylate compound with casein, iron oxide, sulphated castor oil and olive oil; (6) ethyl acrylate compounded with casein, iron oxide and sulphated castor oil; (7) ethyl acrylate; (8) ethyl acrylate and acrylonitrile compounded with borax, wax emulsion, carbon black, casein and sulphated castor oil; (9) ethyl acrylate, isobutyl acrylate and methyl methacrylate compounded with casein, iron oxide, sulphated castor oil and nitrocellulose; and (10) ethyl acrylate, methacrylic acid and N-methylolacrylamide compounded with casein, titanium dioxide and sulphated castor oil.ALSO:Fibrous materials, such as textile fabrics and leather, may be coated with aqueous dispersions of copolymers of 60-96,5% by weight of an acrylic ester of a C1-8 alkanol, 3-30% by weight of acrylic acid and 0,5-10% by weight of N-methylolmethacrylamide.  Preferred esters are those of C2-4 alkanols, particularly ethyl acrylate.  The copolymers may contain minor amounts of additional comonomers, e.g. methacrylic, itaconic, maleic and fumaric acids and esters, acrylonitrile, vinyl esters, vinyl and vinylidene chlorides, N-methylolacrylamide, N-methylolmaleinimide and N-methylolacryloylurea.  Examples describe the coating of (1) leather with aqueous dispersions of a copolymer of ethyl acrylate, acrylic acid and N-methylolmethacrylamide, casein and iron oxide pigment, optionally thickened with ammonia; (2) chrome tanned grain leather from cattle hide with aqueous dispersions of a copolymer of isobutyl acrylate, acrylonitrile, acrylic acid and N-methylolmethacrylamide, casein and lead chromate; (4) cotton corduroy with aqueous dispersions of a copolymer of n-butyl acrylate, acrylic acid and N-methylolmethacrylamide, colloidal silicic acid, an ethylene oxide-isooctylphenol condensate and ammonium nitrate; (5) leather with a dispersion of a copolymer of ethyl acrylate, acrylic acid and N-methylolmethacrylamide, casein, iron oxide pigment, sulphated castor oil and olive oil; or with two coats of a dispersion of the same copolymer, casein and sulphated castor oil, fixed after drying by treating with an aqueous solution of formaldehyde and acetic acid, followed by a top coat of aqueous casein and sulphated castor oil; (6) leather with a dispersion of a copolymer of ethyl acrylate, acrylic acid and N-methylolmethacrylamide, casein, iron oxide pigment and sulphated castor oil, followed after drying by two further coats of similar compositions, the coating being fixed by treating with an aqueous solution of formaldehyde, acetic acid and chromic acetate; (7) goatskins with an under coat of a dispersion of a copolymer of ethyl acrylate, acrylic acid and N-methylolmethacrylamide thickened with ammonia and a top coat comprising nitrocellulose, dibutyl phthalate, castor oil, carbon black, ethyl acetate, butyl acetate and n-butanol; (8) leather with three coats of a dispersion of a copolymer of ethyl acrylate, acrylonitrile, acrylic acid and N-methylolmethacrylamide, borax, wax emulsion, carbon black, casein and sulphated castor oil fixed by treating with an aqueous solution of formaldehyde and acetic acid, followed by a top coat of aqueous casein and sulphated castor oil; (9) the grain side of a vegetable tanned sheepskin with two coats of a dispersion of a copolymer of ethyl acrylate, isobutyl acrylate, methyl methacrylate, acrylic acid and N - methylolmethacrylamide, nitrocellulose, casein, iron oxide pigment and sulphated castor oil, followed by a top coat of an aqueous emulsion of a nitrocellulose lacquer and formaldehyde; and (10) chrome tanned white bag leather with two coats of a dispersion of a copolymer of ethyl acrylate, acrylic acid, methacrylic acid, N-methylolacrylamide and N-methylolmethacrylamide, casein, titanium dioxide and sulphated castor oil, followed by a coat of a similar dispersion comprising additionally formaldehyde, and a top coat comprising a dispersion of a nitrocellulose lacquer and aqueous formaldehyde.