GB841281A - Anti-ozonant compositions for rubber and other unsaturated high polymers - Google Patents

Abstract

A method of protecting unsaturated high polymer material viz elastomers, natural and synthetic, e.g. natural and synthetic rubbers and unsaturated plastomers, from ozone attack comprises incorporating into such high polymer material an effectively antiozonant quantity, as hereinafter defined, of a composition consisting of from 8 per cent to 100 per cent of material selected from Group (A) as hereinafter defined and correspondingly from 92 per cent to 0 per cent of synergistic material selected from Group (B) as hereinafter defined; said effectively antiozonorant quantity being such that the weight ratio of the composition to the high polymer material is at least 2,8:100 when the composition consists entirely of Group (A) material, increasing so that the ratio is at least 4,5:100 when said composition comprises only 55 per cent Group (A) material, at least 5,75 : 100 when said composition comprises only 25 per cent Group (A) and 75 per cent Group (B) material and at least 6,25 : 100 when said composition comprises 8 per cent Group (A) material and 92 per cent Group (B) material; the Group (A) material being substituted p-arylene diamine material represented by the formula R-NH-R1-NH-R11 wherein R1 is an unsubstituted or hydrocarbon substituted p-phenylene, p,p1-biphenylene, -methylenediphenylene or iminodiphenylene radical; R is a hydrogen atom, or an unsubstituted or hydrocarbon substituted sec-alkyl, cycloalkyl or phenyl substituent limited however to unsubstituted and hydrocarbon substituted phenyl substituents when R1 is a phenylene radical; and R11 is an unsubstituted or hydrocarbon substituted sec-alkyl or cycloalkyl radical limited, however, to unsubstituted and hydrocarbon substituted cyclo-alkyl radicals when R1 is phenylene and wherein the total carbon atom count of R + R1 + R11 lies within the range of 18 to 31 when R1 is a phenylene radical, decreases to the range of 20 to 29 when R1 is other than a monophenylene radical and no ring structures are present in said substituents R and R11, shifted to the range of 18 to 28 when ring structure is present in at least one of said substituents R and R11, and counting as two carbon atoms the imino nitrogen when present in R1; the Group (B) material, when present, contributing synergistically to the antiozonant effectiveness of the composition and being selected from the group of synergists consisting of sub-group (i) the amine antioxidants for rubber, the phenolic antioxidants for rubber, the phosphite antioxidants for rubber, the aromatic ester antioxidants for rubber and the thioamides, sub-group (ii) the paraffin waxes and microcrystalline waxes, the subgroup (iii) tin, iron, cobalt and nickel soaps of organic acids selected from the class consisting of fatty acids, rosin acids, tall oil acids and naphthenic acids and their hydrogenated and oxygenated derivatives. Among the synthetic rubbers specified are polybutadiene, GR-S and other diene vinyl copolymers e.g. acrylonitrile-butadiene elastomers, butyl rubber, neoprene, copolymers of styrene and butadiene with copolymerized carbonyl containing monomers e.g. methyl vinyl ketone, crotonaldehyde or methyl isopropenyl ketone. Other polymers and copolymers mentioned include those derived from vinyl chloride, vinyl acetate and alkylacrylates. Specific antiozonants within group (A) employed in compositions described include N-phenyl-N1-cyclohexyl-p-phenylene diamine, N-2-naphthyl-N1-cyclohexyl-p-phenylene diamine, N,N1-di-2-octyl-benzidine, N-2-octylbenzidine, N,N1-di-sec-hexyl benzidine, di-sec-butyl-benzidine, N,N1-di-sec-hexyl-, N,N1-di-2-octyland N,N1-di-sec-nonyl - pp1-di aminodiphenyl-methanes, N-phenyl -N1-3,5,5- trimethyl cyclohexyl - p - phenylene diamine p,p1-di (sec-octyl amino-) and p,p1 dicyclohexylamino-diphenylamine. Many synegistic materials within the definition of the group B material are listed. Examples of the compositions of the invention and comparative examples are furnished.