Patent GB-1438505-A (GB)
Title: Method of treating leather
IPC: C14C11/00
Filed: 1973-05-09
Abstract: 1438505 Coated leather SUMITOMO CHEMICAL CO Ltd 9 May 1973 [9 May 1972 4 Oct 1972 5 Oct 1972] 22212/73 Heading B2E Leather is treated with a copolymer 1, of A consisting of an aliphatic α-olefine or halogensubstituted aliphatic α-olefine having from 3-20 carbon atoms and B a mono-ethylenically unsaturated ester containing 4-22 carbon atoms. The composition may also comprise 0.1-100 parts by weight of a polymer 2 whose main molecular chain includes a unit of formula: in which X<SP>1</SP>, X<SP>2</SP> and Z, which may be the same or different, are each a hydrogen, halogen, or RY<SP>1</SP> or R<SP>1</SP>Y<SP>1</SP> where Y<SP>1</SP> is -C#N, CO.OR, -O.CO.OR or -OR, R being a hydrocarbon or halohydrocarbon having 1-20 carbon atoms, and R<SP>1</SP> being a divalent hydrocarbon or halohydrocarbon having 1-20 carbon atoms, provided that at least one of X<SP>1</SP> and X<SP>2</SP> is a hydrogen atom. The treatment renders the leather surface resistant to colour bleeding. Many examples of unsaturated ester component of copolymer 1 are given, esters of acrylic acid or methacrylic acid, and vinyl esters of fatty acids being preferred. Examples of A are also given, isobutylene or propylene being preferred. Copolymer 1 may be converted into a reactive polymer by copolymerisation or graft copolymerisation with a third component which is a vinyl, vinylidene or vinylene compound having 3-40 carbon atoms and containing an acyl halide, amide, carboxyl, acid anhydride, nitrogen-containing heterocyclic, nitrile or aldehyde radical, or is a compound containing a hydroxyl, amino, epoxy, ether or isocyanate radical preferred compounds being acrylic acid, acryloyl halides, acrylamide and substituted acrylamides, maleic anhydride, maleimide or substituted malimides, fumaric acid, acrylonitrile, vinyl pyridines, acrolein. Many other examples are given. Polymer 2 may be a polymer, copolymer, block copolymer or a graft copolymer. Specific examples of polymer 2 are polystyrene, poly-p-chlorostyrene, polyacrylonitrile, polymethylacrylate or methacrylate, polyvinyl acetate, poly-(2-chloroethyl vinyl ether), polyvinyl or polyvinylidene chloride, polybutadiene, polyisoprene, polychloroprene, ethylene-vinyl acetate copolymer, ethylene-ethylacrylate copolymer, styrenemethyl methacrylate copolymer, styrene-acrylonitrile copolymer, isobutylene-isoprene copolymer, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, polybutadienestyrene graft copolymer, polybutadiene-methyl methacrylate-styrene graft copolymer, polybuta diene-acrylonitrile-styrene graft copolymer, styrene-butadiene block copolymer, 6-nylon, 6, 10-nylon, polyurethane and poly(gammamethyl glutamate). Polymer 2 may be converted into a reactive polymer as described in connection with copolymer 1. The composition may also include 0.1-100 parts by weight of an inorganic powder, preferably silica gel, alumina, titanium oxide, calcium carbonate. The composition may be applied as a solution or dispersion by brushing, spraying, dipping or knife coating. The composition may also be applied as a belt. The term "leather" includes natural and artificial leather such as polyamide, amino acid, polyurethane and vinyl chloride leather optionally covered with a coloured surface layer. In a typical example an isobutylene-methylacrylate-acryloyl chloride copolymer is applied as a solution in toluene with a brush to a leather having a surface layer of polyurethane containing a colourant.