GB684126A - Compositions containing rubber antioxidants - Google Patents

Abstract

Rubber antioxidants in the form of free-flowing granules comprise the powdered antioxidant with 0.05-3.5 per cent of its weight rubber latex solids as binder. The rubber latex employed may be a dispersion of butadienestyrene copolymer, butadiene-acrylonitrile copolymer, or neoprene, or a dispersion made on emulsion polymerization of one or more butadienes-1,3, e.g. butadiene-1,3, 2-methyl butadiene-1,3, 2-chlorobutadiene-1,3, 2,3-dimethyl butadiene-1,3, and piperylene with one or more other polymerizable compounds capable of forming rubber copolymers with butadienes-1,3, e.g. styrene, vinyl naphthalene, acrylic acid, methyl acrylate, methyl methacrylate, acrylonitrile, methacrylonitrile, methacrylamide, methyl vinyl ether, methyl vinyl ketone, and vinylidene chloride.ALSO:Rubber antioxidants in the form of free-flowing granules comprise the powdered antioxidant with 0.05-3.5 per cent of its weight rubber latex solids as binder. The antioxidant, exemplified by N,N1-diphenyl-p-phenylenediamine, N-N1-dibetanaphthyl-p-phenylenediamine, p-(p-tolyl-sulphonylamide)-diphenylamine, phenylbetanaphthylamine, the reaction product at 150 DEG C. of phenylbetanaphthylamine and acetone, and the reaction product at 150 DEG C. of diphenylamine and acetone, ground to pass a sieve of 0.0021 in. aperture, is made into a paste with latex containing the required amount of latex solids, the paste is extruded in columnar form, and the extruded paste is broken into short pieces and dried, granules of diameter 0.05-0.15 in. and length 0.125 to 0.25 in. being preferred. Substances which increase the hardness of the granules, e.g. carboxymethyl or carboxyethyl cellulose, starch, dextrose, glue, gelatine, casein, gum tragacanth, locust bean gum, gum arabic, gum karaya, silica gel, or rosin soap may be incorporated in amount 0.2-1 part per 100 parts of antioxidant. The latex employed is preferably natural rubber latex or creamed or centrifuged natural rubber latex, but there may be used a dispersion of neoprene, butadiene-styrene copolymer, or butadiene-acrylonitrile copolymer, or, generally, a dispersion obtained on emulsion polymerization of one or more butadienes-1,3 with substances which form rubbery copolymers therewith.