GB983908A - Process for the treatment of leather - Google Patents

Abstract

Leather is finished by treatment with aqueous copolymer dispersions prepared in the absence of emulsifying agents and comprising, on a weight basis, at least 50% of esters of acrylic acid with alcohols containing 1 to 20 carbon atoms and/or esters of methacrylic acid with alcohols containing 4 to 20 carbon atoms, at least 10% of acrylamide and/or its b - or N substitution products, and optionally halogen-free compounds copolymerizable with the foregoing ester(s) and amide(s), e.g. acrylonitrile, acrylic acid, methacrylic acid and its esters with alcohols containing 1 to 3 carbon atoms, di- and semi-esters of maleic and fumaric acids, vinyl esters of carboxylic acids styrene, vinyl toluene, and conjugated dienes such as 1,3-butadiene and its 2-methyl and 2,3-dimethyl derivatives. Suitable esters of acrylic or methacrylic acid include methyl-, ethyl-, isopropyl, b -hydroxy propyl-, n-butyl, octyl, hexadecyl and octadecyl acrylates and butyl, dodecyl and octadecyl methacrylate. Examples of a - or N-substitution products of acrylamide include: methacrylamide, a -ethylacrylamide, a -chloroacrylamide, a -cyanoacrylamide, a -carboxyacrylamide, N-methylacrylamide, N-methylmethacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N - tert. - butylacrylamide and N,N-di-n-butylmethacrylamide. The dispersions, which may be prepared by known methods, may incorporate protective colloids, thickeners, stabilizers or softeners, e.g. polyvinyl chloride, polyacrylamide, alkali metal polyacrylates, methyl cellulose, alginates, gums, gelatine, linseed oil, castor oil, turkey red oil, fatty acids, polyalkylene oxides; water-miscible organic liquids such as formamide, acetamide, alcohols, glycerol, glycols cyclic esters, e.g. dioxan and tetrahydrofuran; compounds which react with carboxylamide groups in the copolymers such as formaldehyde, glyoxal (with or without casein), and preliminary condensation products of formaldehyde with urea, dicyanodiamide or melamine.ALSO:Leather is finished by treatment with aqueous copolymer dispersions prepared in the absence of emulsifying agents and comprising, on a weight basis, at least 50% of esters of acrylic acid with alcohols containing 1-20 carbon atoms and/or esters of methacyrlic acid with alcohols containing 4-20 carbon atoms, at least 10% of acrylamide and/or its a - or N-substitution products, and optionally halogen-free compounds copolymerizable with the foregoing ester(s) and amide(s), e.g. acrylonitrile, acrylic acid, methacrylic acid and its esters with alcohols containing 1-3 carbon atoms, di- and semi-esters of maleic and fumaric acids, vinyl esters of carboxylic acids, styrene, vinyl toluene, and conjugated dienes such as 1,3-butadiene and its 2-methyl and 2,3-dimethyl derivatives. Suitable esters of acrylic or methacrylic acid include methyl-, ethyl-, isopropyl, b -hydroxy propyl, n-butyl, octyl, hexadecyl and octadecyl acrylates and butyl, dodecyl and octadecyl methacrylate. Examples of a - or N-substitution products of acrylamide include methacrylamide, a -ethylacrylamide, a -chloroacrylamide, a -cyanoacrylamide, a -carboxyacrylamide, N-methylacrylamide, N-methyl methacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-tert.-butylacrylamide, and N,N-di-n-butyl methacrylamide. The dispersion, which may be prepared by known methods, may incorporate protective colloids, thickeners, stabilizers or softeners, e.g. polyvinyl chloride, polyacrylamide, alkali metal polyacrylates, methyl cellulose, alginates, gums, gelatine, linseed oil, castor oil, Turkey Red oil, fatty acids, polyalkylene oxides; water-miscible organic liquids such as formamide, acetamide, alcohols, glycerol, glycols, cyclic esters, e.g. dioxan and tetrahydrofuran; compounds which react with carboxylamide groups in the copolymers such as formaldehyde, glyoxal (with or without casein), and preliminary condensation products of formaldehyde with urea, dicyanodiamide or melamine. The dispersions may be applied repeatedly to the leather, which may then be dried and pressed. A colour may then be applied, e.g. together with a casein solution or a wax or polymer emulsion.