Improvements in and relating to acrylate ester copolymers

摘要

A copolymer of at least one ester of a primary monohydric alcohol and acrylic acid and at least one ester of acrylic acid and a monohydroxy compound having the OH groups on a C atom which is free of H. The copolymer may contain 20-80% of at least one monomer, CH2=CHCOOCH2R, where R is an alkyl group having from 3-9 C atoms, e.g. n- or isobutyl, n- or iso-amyl acrylates or the acrylate esters of the monohyric primary hexyl, heptyl,octyl, nonyl or decyl alcohols; and 80-20% of at least one monomer, CH2=CHCOOR1, where R1 is an aromatic hydrocarbon group having 6-10 C atoms, e.g. phenyl, o-, m- or pcresyl or a - or b -naphthyl acrylates; or monomer, where R2, R3 and R4 are aliphatic hydrocarbon groups having from 1-7 C atoms and whose total C atoms is not more than 10, e.g. t-butyl or t-amyl acrylate or the acrylate esters of the monohydric t-hexyl, t-heptyl, t-nonyl or t-decyl alcohols. The copolymers may be 40-55% n-butyl and 45-60% t-butyl acrylates; 50-70% 2-ethylhexyl and 30-50% t-butyl acrylates; 50-80% n-butyl and 20-50% t-amyl acrylates; 20-30% a - or b -naphthyl and 70-80% n-butyl acrylates; and 40-50% phenyl and 50-60% n-butyl acrylates. The copolymers may be produced by copolymerizing the acrylate esters in a solvent with free radical initiator at 0 DEG -100 DEG C., or by using mass or emulsion polymerization. The solvent may be toluene, xylene, mesitylene, benzene, bromo-trichloromethane, CHCl3, methyl ethyl ketone, methyl isobutyl ketone, butane, pentane, hexane, heptane, ethyl or propyl acetate, ethyl propionate or mixtures thereof. The radical initiator, e.g. 0,1-5 parts, may be peroxides, e.g. benzoyl hydroperoxides, acyl peroxides, azo compounds and redox initiators, or the free radicals may be generated by radiant energy, e.g. U.V. light, g - or X-rays. The copolymers have molecular weights corresponding to dilute solution viscosities of 0,25-1,75. In an example n-butyl/t-butyl acrylate copolymer was prepared at 50 DEG C. in O2-free N2 using methyl ethyl ketone and azobisisobutyronitrile. Specification 779,687 is referred to.