Thermosetting resin, and its production and use

Claim 1

A process for preparing a thermosettable resin of self cross-linking type, which comprises polymerizing (1) 0.5 to 30% by weight of at least one polymerizable monomer having an ionic structure selected from the group consisting of (i) a compound of the formula: ##STR7## wherein R 1 is hydrogen or methyl, R 2 and R 3 are each C 1 -C 6 alkyl, A is --O-- or --NH--, m 1 and n 1 are each an integer of 1 to 12 and X.sup.⊖ is SO 3 .sup.⊖, SO 4 .sup.⊖ or CO 2 .sup.⊖, (ii) a compound of the formula: ##STR8## and (iii) a compound of the formula: ##STR9## wherein, the formulae (II) and (III), R 4 is hydrogen or methyl, R 5 is hydrogen or C 1 -C 3 alkyl, m 2 is zero or an integer of 1 to 6, n 2 is an integer of 1 to 6 and A and X.sup.⊖ are each as defined above, (2) 1 to 25% by weight of at least one polymerizable monomer containing an oxirane group selected from the group consisting of a compound of the formula: ##STR10## and a compound of the formula: ##STR11## wherein, in formulae (IV) and (V), R 6 and R 7 are each hydrogen or methyl, and (3) 45 to 98.5% by weight of at least one ethylenically unsaturated polymerizable monomer other than said polymerizable monomer having an ionic structure and said polymerizable monomer containing an oxirane group, said polymerization being carried out in the presence of 0.05 to 5% by weight of a polymerization initiator, based on the total weight of the monomers to be polymerized, with the proviso that the polymerizable monomer component (3) includes a carboxyl group-containing polymerizable monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, a monoester of maleic acid, itaconic acid, a monoester of itaconic acid, fumaric acid and a monoester of fumaric acid, of which the amount is from 2 to 20% by weight based on the total weight of the monomers to be polymerized said thermosettable resin of self cross-linking type having a property such that if an aqueous dispersion of said resin in a concentration of 50% by weight is applied to a tin plate and dried to obtain a film having a thickness of 10 to 15μ, and said film is baked at 160° C. for 10 minutes to obtain a hardened film, said hardened film will have an acetone-insoluble solid content of not less than 50% by weight.