Patent GB-1060785-A (GB)
Title: A process for cross-linking polymers
Inventor: BONIN WULF VON
IPC: D06M15/263
Filed: 1964-08-28
Abstract: A process for cross-linking polymers present in latex form comprises reacting together in aqueous emulsion (A) a carboxylic acid compound, (B) a carbonyl compound and/or an amine compound having one or more primary or secondary amino groups and (C) an isonitrile, wherein (1) at least two of the compounds are polyfunctional, (2) at least one of the compounds is polymeric having a molecular weight above 300, (3) the ratio of compounds A and C is chosen so that 0.5 to 1.5 carboxyl groups are available to each isonitrile group and (4) compounds A and B are used in such proportions that 0.5 to 1.5 carboxyl groups are available to each carbonyl or primary or secondary amino group. Cross-linking may be effected by stirring the latex with the cross-linking system at 0 to 100 DEG  C. at acid, neutral or alkaline pH. Additional cross-linking agent may be present, e.g. urea-formaldehyde precondensates, melaminemethylol compounds and masked isocyanates; also present may be fillers, solvents and plasticizers, e.g. triethyl phosphate.  As polymeric compounds A there may be used homopolymers or copolymers of acids such as acrylic, methacrylic, itaconic, maleic and fumaric acid and semi-esters of the specified dibasic acids, e.g. the monododecyl ester of maleic acid.  Suitable polymers B are copolymers of acrolein, methyl vinyl ketone, 2-aminoethyl methacrylate and 2-methylaminoethyl methacrylate (which amino compounds may be in the form of acetic acid addition salts), and polyalkylenepolyamines. Polymers containing, for example, both acid and carbonyl groups, or carbonyl and amino groups are also suitable.  In examples, the acid, carbonyl and/or amino components of the polymers are copolymerized with one or more of ethyl acrylate, butyl acrylate, methyl methacrylate, methacrylamide, acrylonitrile, vinyl acetate, styrene and butadiene.  Long lists of non-polymeric cross-linking components of types A, B and C are given.  The examples disclose the preparation by emulsion polymerization of a butyl acrylate-ethyl acrylate-methyl methacrylate-methacrylic acid copolymer using a potassium persulphate-triethanolamine catalyst and an ethyl acrylate-acrolein copolymer using a potassium persulphate-sodium disulphite catalyst. The final example illustrates the cross-linking of a mixture of polymers comprising an acrylonitrile - styrene - methacrylamide - methacrylic acid copolymer and an acrylonitrilemethacrylic acid-styrene-butadiene copolymer. The cross-linkable latexes have many applications including forming films and coatings; in such cases cross-linking is effected with the latex supported on a suitable substrate.ALSO:In an Example (14), fibre fleeces based on regenerated cellulose and poly-e -caprolactam respectively are saturated with an aqueous latex comprising a n-butyl acrylate-ethyl acrylate-methyl methacrylate-methacrylic acid copolymer, methyl-di-(3-isocyanopropyl)-amine and ethyl amyl ketone, squeezed and dried at 70 DEG C.  The fleeces so treated are rendered resistant to shrinking and extraction by boiling perchloro-ethylene.ALSO:In an Example (35), an iron sheet is coated with an aqueous latex comprising an acrylonitrilestyrenemethacrylamidemethacrylic acid copolymer, an acrylonitrilemethacrylic acid-styrene-butadiene copolymer, ethyl n-amyl ketone, 1,1,3-tri(3-isocyanopropyl)-indane and triethyl phosphate, dried at 90 DEG C., and finally baked for 10 minutes at 110-140 DEG C.