GB930467A - Heat-curable copolymers and varnishes prepared therefrom - Google Patents

Abstract

A copolymer of (A) a monoamide of a C4-C6 olefinically unsaturated dicarboxylic acid, wherein the carbonamide group may be mono- or di-substituted on the N atom by an aliphatic, cycloaliphatic or aromatic radical; (B) one or more compounds containing a -CH=CH2 or <FORM:0930467/IV(a)/1> group; and (C) one or more alpha-beta olefinically unsaturated mono- or di-carboxylic acids, esters or anhydrides, wherein the mol. ratio of (A):(B+C) is between 0,05 and 1 : 1 and of (B):(C) is between 10 and 0,1 : 1, has the N atoms of the carboxylic acid amide groups substituted by alkoxymethyl groups. The alkoxymethyl groups may be introduced before, during or after polymerization by means of formaldehyde and the appropriate monohydric alcohol. It is also possible to introduce the monoamide groups themselves after polymerization by treating a copolymer derived from a dicarboxylic acid or anhydride with an appropriate amount of an amine. (A) may be a monoamide of maleic or fumaric acid; (B) may be a vinyl ether, vinyl ester, e.g. the acetate, or a vinyl aromatic compound, e.g. styrene or alpha methyl styrene; (C) may be acrylic, maleic or fumaric acid, maleic anhydride, or methyl or ethyl acrylate. In forming the alkoxymethyl groups the alcohol may be used in a 5 to 10 times excess and water of condensation continuously removed to yield a p solution which can be used directly as a varnish. The solutions may also be mixed with other varnish resins, e.g. phenol, urea, melamine, epoxy or alkyd varnish resins. 2 to 20 wt. per cent of epoxy resin is said to donate practically unlimited stability in caustic soda solution. In examples:-(1) 20 parts N-butyl maleic or fumaric acid monoamide, 40 parts styrene and 40 parts ethyl acrylate are polymerized in butanol using benzoyl peroxide as catalyst and subsequently treated with formaldehyde; the resulting solution is used as a varnish alone or mixed with 10% of an epoxy resin based on dihydroxydiphenyldimethylmethane having an epoxy No. of 0,2; (2) the monomers used are 30 parts N-cyclo-hexyl-maleic acid monoamide, 30 parts ethyl acrylate and 40 parts styrene; (3) the monomers are 20 parts N-butyl-maleic acid monoamide, 40 parts styrene, 30 parts ethyl acrylate and 10 parts vinyl ethyl ether; (4) 40 parts styrene, 40 parts ethyl acrylate and 11,5 parts maleic anhydride are polymerized in toluene with benzoyl peroxide as catalyst, precipitated, amidated with 2 parts ammonia, and then treated with excess butanol and formaldehyde. Specification 792,874 is referred to.