1,262,985. Stabilizing polymers. B. F. GOODRICH CO. 31 Oct., 1969 [31 Oct., 1968], No. 53412/69. Headings C3G, C3P, C3Q and C3R. [Also in Divisions C2, C5 and D1] Stabilizers for polymeric materials comprise hexahydro - 1,3,5 - tris(4 - hydroxyaryl) - striazines of the formula in which R 1 and R 2 are C 4-18 tertiary alkyl groups, RSP3/SP is hydrogen or C 1-18 alkyl and RSP4/SP is hydrogen or C 1-4 alkyl. The stabilizers may be incorporated in natural or synthetic addition or condensation polymers in amounts of 0À001- 10% by wt., alone or with other known stabilizers with which a synergistic effect may be obtained. Other specified stabilizers include dithiocarbamates, zinc dialkylthiophosphates, organic sulphides, compounds of the formula ROOC.CH 1 CH 2 SCH 2 CH 2 COOR, where R is C 6-20 alkyl, and sterically hindered phenols. Many polymeric substrates are specified. Examples describe the stabilization of (II) a polyvinylchloride/methyl methacrylate - butadiene - styrene copolymer blend, (III) polyethylene, (IV) and (V) polypropylene where the stabilizer is used or in conjunction with dilauryl or distearyl thiodipropionate, (VI) natural rubber white stock, (VII) ethylenepropylene - ethylidene norbornene copolymer, (VIII) ethylene - propylene - methyltetrahydroindene copolymer, (IX) an ABS graft resin, polystyrene, nylon 6, ethyl acrylateacrylonitrile copolymer, polyethylene terephthalate, polyoxymethylene, and an acetal copolymer resin, (X) ethyl acrylate-acrylonitrile copolymer, (XI) a polyurethane and (XII) various foam compositions having two components selected from natural rubber, polybutadiene rubber and styrene-butadiene rubber, together with polystyrene.
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