Verfahren zur Herstellung vernetzender UEberzugsmassen

摘要

A copolymer is derived from a monomer mixture containing at least 50% by weight of acrylic and/or methacrylic acid esters, from 0.5 to 30% of an azlactone of formula (in which R1 and R2 represent alkyl, cycloalkyl aryl or aralkyl groups, or R1 and R2 together with the adjacent carbon atom represent a carbocyclic or heterocyclic ring system, and R3 represents a group containing a polymerizable carbon-carbon double bond), and, if desired, up to 49.5% of one or more further comonomers. Specified comonomers are acrylic and methacrylic acids, nitriles, amides, or N-substituted amides thereof, styrenes, vinyl esters and olefins. The copolymers may be cross-linked with a compound containing a primary or secondary amino group, or a hydroxyl, mercapto and/or hydrazide group, e.g. ethylene diamine, triaminoethylamine, N,N1-di - (tert. - butylhdroxycarbonyl) - hexamethylenediamine, N - aminoethylpiperazine, ethylene glycol, butanediol, glycerol, dimercaptoethane, ethanolamine, glutaric acid dihydrazide, polyethylene glycol, polyvinyl alcohol, polyethyleneimine, an epoxy resin or a polyester. Alternatively, the copolymer may contain functional groups capable of interacting to effect cross-linking, e.g. when b -hydroxyethyl methacrylate is one of the monomers. Cross-linking catalysts such as H3PO4 or a sodium alcoholate may be used, for instance when the composition is employed as a coating composition. In Examples 1 to 8 the copolymers are produced in solution in one or more solvents selected from ethyl acetate, methyl ethyl ketone and ethyl glycol acetate, the catalyst (azoisobutyric acid nitrile or dilauroyl peroxide) being added in two stages and the cross-linking agents being ethylene diamine, hexamethylene diamine, butanediol, adipic acid dihydrazide and p-toluene sulphonic acid, or a vinyl acetate-vinyl alcohol copolymer and said acid, or trichloroacetic acid. The copolymers are as follows: Examples 1 and 8, an ethyl acrylate, methyl methacrylate, 2-isopropenyl - 4,4-dimethyl oxazolone-5 copolymer; Example 2, a n-butyl acrylate, acrylonitrile, methyl methacrylate, styrene, 2-isopropenyl-4-methyl-4-n-propyl oxazolone-5 copolymer; Example 3, a n-butyl methacrylate, N-methyl methacrylamide, 2 - vinyl - 4,4 - pentamethylene - oxazolone-5 copolymer; Example 4, a 2-ethylhexyl acrylate, methyl methacrylate, methacrylic acid, 2 - vinyl - 4 - methyl - 4 - phenyl - oxazolone-5 copolymer; Example 5, a methyl acrylate, vinyl acetate, diethyl fumarate, 2 - vinyl - 4 - methyl - 4 - benzyl - oxazolone - 5 copolymer; Example 6, a 2-ethylhexyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, 2 - acryloxyethyl - 4 - methyl - 4 - cyclohexyl - oxazolone-5 copolymer, and Example 7, an ethyl acrylate, methyl methacrylate, methacrylic acid, 2-isopropenyl-4,4-dimethyloxazolone - 5 copolymer. In Example 9, a copolymer of ethyl acrylate, methyl methacrylate and 2-isopropenyl-4,4-dimethyloxazolone-5 is produced in an aqueous emulsion containing an ethylene oxide-isononyl phenol condensate as emulsifier and the sodium salt of 4,41 - dicyano - 4,41 - azodivaleric acid as catalyst. Other oxazolone monomers specified are 2 - isopropenyl - 4,4 - di - n - propyl - oxazolone - 5 and 2 - vinyl - 4 - methyl - 4 - benzyl-oxazolone-5.