GB664432A - Interpolymers of oxidized drying oils and alkenyl aromatic compounds and compositions comprising same - Google Patents

Abstract

Toluene-soluble resins are made by copolymerizing at elevated temperatures a monovinyl aromatic hydrocarbon having less than 12 carbon atoms in the molecule, a mono-alpha-alkyl vinyl aromatic hydrocarbon containing less than 13 carbon atoms in the molecule and having less than 5 carbon atoms in the alkyl-vinyl group, and a drying oil which in its raw state has a degree of conjugation not greater than 25 per cent and which has been oxidized by an oxygen-containing gas so that its combined oxygen content is increased by at least 10 per cent, the proportions being from 80 to 20 parts of the oxidized drying oil and from 20 to 80 parts of a mixture consisting of from 10 to 40 per cent of the alpha-alkyl vinyl compound and from 90 to 60 per cent of the monovinyl compound. Polymerization is preferably effected en masse at temperatures between 100 DEG and 300 DEG C. in the presence of an organic peroxide catalyst such as benzoyl, lauroyl, or acetyl peroxide. If desired, either or both alkenyl aromatic reactants may be added gradually to the heated oil. Solvents such as benzene, toluene, ethylbenzene and xylene may be, but are preferably, not used. Suitable monovinyl compounds are styrene, o-, m-, and p-methyl and ethyl styrenes, ar-monoisopropyl styrene, ar-methyl-ar-ethyl styrenes and ar-dimethyl styrenes. Mixtures of two or more may be used. Specified alkyl vinyl compounds are a -methyl styrene, a - ethyl styrene, ar - methyl - alpha-methyl styrenes, ar-dimethyl-alpha-methyl styrenes, ar - ethyl - alpha - methyl styrenes and ar-isopropyl alpha-methyl styrenes. Suitable drying oils are linseed, soyabean, dehydrated castor and sardine oils. Mixtures of these or with highly conjugated oils may be used provided that the average degree of conjugation is not greater than 25 per cent. The oils may contain minor amounts of the free acids or of mono- or di-glycerides of the acids. Synthetic oils such as ethylene glycol or propylene glycol esters of drying oil fatty acids may also be used. The oil is oxidized by blowing air, oxygen or oxygen-containing gas through the oil heated to temperatures of from 50 DEG to 300 DEG C. After polymerization, the unreacted material may be removed by treatment with steam or by heating under vacuum. The gummy or resinous copolymers are soluble in paint and varnish solvents such as benzene, toluene, xylene, mineral spirits and the material known under the Registered Trade Mark "Solvesso." Driers such as lead and cobalt naphthenates and pigments may be added and the compositions form films which dry in air, apparently undergoing oxidation to form hard tack-free coatings. Specifications 573,835, [Group IV (b)], 621,542 and U.S.A. Specification 1,975,959 are referred to.