Composition consisting of the reaction product of a linear synthetic polymer and a monocarbodiimide and process for crosslinking

Cross-linked polymers are prepared by reacting linear synthetic polymers of polymerizable ethylenically unsaturated monomers, which polymers contain carboxyl or sulphonic acid groups and at least one of the monomers being an a , b -olefinically unsaturated acid and the polymer containing at least 0,005 chemical equivalents by weight of organic acid hydrogen for each 100 parts by weight of polymer and having a molecular weight of at least 500, with monocarbodiimides. Preferred carbodiimides are N, N1-diisopropyl-, N, N1-diisobutyl-, N, N1-diisoamyl-, N, N1-dicyclohexyl-, N, N1-diphenyl-, N-phenyl-N1-p-chlorophenyl-, and N-isopropyl-N1-p-dimethylaminophenyl carbodiimides. The rate of reaction may be controlled by adding ammonia and amines. The polymers may be prepared by polymerization in bulk, solution or emulsion in the presence of emulsifiers e.g. sodium naphthalene sulphonate-formaldehyde condensates and sodium alkylaryl sulphonates, buffers, catalysts, e.g. organic peroxides and hydroperoxides, azodinitriles and persulphatesulphite redox systems, and modifiers, e.g. mercaptans, sulphides, disulphides, bromotrichloromethane, di-bromodichloromethane, cumene and xylene. Many suitable monomers are listed and examples describe the reaction of N, N1-dicyclohexyl carbodiimide with (I, II, III, VIII and XV) butadiene-acrylonitrile-methacrylic acid copolymers; (IV and XI) butadiene-methacrylic acid copolymers; (V and X) butyl acrylatemethacrylic acid-acrylic acid copolymers; (V) maleic acid-butyl acrylate copolymers; (IX) butadiene-styrene-methacrylic acid copolymers with (VII and XVIII) carbon black; (XIII and XIV) chloroprene-methacrylic acid copolymers; (XVI) butadiene-acrylonitrile-ethylene sulphonic acid copolymers and (XVIII) poly-a -sulphonyl acrylic acid; N, N1-diphenyl carbodiimide with (I) butadiene-acrylonitrile-methacrylic acid copolymer; N, N1-diisopropyl carbodiimide with (VI) butadiene-acrylonitrile-methacrylic acid copolymer with (XIX) carbon black; and N, N1-didodecyl carbodiimide with (XII) butyl acrylate-methacrylic acid-acrylic acid copolymer. The products may be used for coating, e.g. glass and aluminium, inpregnating leather, as caulking compounds and putties, binders for solid fuels, and binders for non-woven articles of cotton, wool, asbestos and synthetic fibres.