GB1106083A - Copolymers - Google Patents

Abstract

A copolymer is made from (A) a compound containing an epoxide ring and copolymerizable double bond, (B) an alpha-beta unsaturated carboxylic acid, and (c) a vinyl or vinylidene monomer or mixture of monomers free from epoxide groups, active-hydrogen containing groups, and nitrile groups, the ratio of epoxy to carboxy groups in the copolymer being between 1:6 and 6:1 and the ratio of the sum of the weights of (A) and (B) to the total monomer weight being not greater than 1:2 and not less than 1:5, the molecular weight and gel content of which copolymer have been limited through the presence during the formation of the copolymer of a chain transfer agent. The polymerization is suitably carried out using a free radical initiator. The copolymers may be cured by moderate heat, suitably in the presence of a catalyst such as a tertiary amine. In the Examples, copolymers of (1-3) methyl methacrylate, n-butyl acrylate, glycidyl methacrylate and acrylic acid, (4) methyl and n-butyl methacrylates, glycidyl methacrylate and methacrylic acid, (5) n-butyl acrylate, methyl methacrylate, glycidyl acrylate and acrylic acid, and (6) methyl methacrylate, n-butyl acrylate, allyl-9:10-epoxystearate, and acrylic acid are prepared using methyl ethyl ketone peroxide as initiator, ethylene glycol monoethyl ether as solvent, and dodecyl mercaptan as chain transfer agent. The resulting copolymers are formed into solutions in a xylol/butanol mixture and mixed with TiO2.ALSO:A curable coating comprises a copolymer made from (A) a compound containing an epoxide ring and copolymerisable double bond, (B) an alpha-beta unsaturated carboxylic acid, and (C) a vinyl or vinylidene monomer or mixture of monomers free from epoxide groups, active-hydrogen containing groups, and nitrile groups, the ratio of epoxy to carboxy groups in the copolymer being between 1:6 and 6:1 and the ratio of the sum of the weights of (A) and (B) to the total monomer weight being not greater than 1:2 and not less than 1:5, the molecular weight and gel content of which copolymer have been limited through the presence during the formation of the copolymer of a chain transfer agent. The coatings may also include a pigment such as TiO2, and may be cured by moderate heat under force-drying conditions using a catalyst, suitably a tertiary amine. The coating of glass plates and aluminium panels is exemplified.