GB923190A - Antioxidant compositions - Google Patents

Abstract

Fats and fatty oils, e.g. lard, beef tallow, fish oils, and vegetable oils and shortenings; waxes; liquid hydrocarbon fuels such as gasoline, which may contain antiknock agents such as tetraethyl lead and halogen- and phosphorus-containing scavengers, kerosene, diesel oils, fuel oils and turbine oils; hydrocarbon lubricating oils which may contain barium sulphonate detergents, and insulating oils; synthetic diester lubricating oils, such as the adipates and sebacates; polyalkylene glycol lubricants; hydraulic fluids; and greases obtained by adding metallic soaps (including resin soaps) to lubricating oils together with such further additives as fats, fatty acids, alkalis, glycerol, fatty alcohols, resin, wool grease, water, and modifiers and peptizers; contain a synergistic antioxidant composition which comprises (a) a phosphite ester of formula <FORM:0923190/III/1> wherein R1, R2 and R3 are alkyl, alkoxyalkyl, haloalkyl, cycloalkyl, halocycloalkyl, aralkyl, alkaryl, haloaryl or haloalkaryl radicals, and R3 may also be hydrogen, and (b) a methylene bisphenol of formula <FORM:0923190/III/2> wherein R4 is a C3-12- alkyl group which is branched on the a -carbon atom and R5 is a C1-12- alkyl group, the weight ratio (b) to (a) being 0,005-1000. In general the material to be stabilized contains 0,025-4% of (a) and 0,01-5%, preferably 0,1-3% of (b) by weight, there preferably being present 0,5-5 moles of (a) per mole of (b). (a) is most suitably a di-C1-12-alkyl hydrogen phosphite, and (b) is preferably 4:41-methylene bis(2:6-diisopropylphenol) or 4:41-methylene bis(6-tert.butyl-o-cresol).ALSO:Addition polymers such as polystyrene, polyvinyl chloride and acetate and particularly polymers of C2-5- mono-olefins such as butylene, isobutylene, 2-methyl-4-butene, and 2-methyl-3-butene, but especially polyethylene and-propylene; condensation polymers such as epoxide, polyester and alkyd resins; elastomers such as natural rubber, oil extended and sulphur-vulcanized rubbers, and synthetic rubbers such as polybutadiene, methyl rubber, polybutadiene rubber, butyl rubber, GR-S and GR-N rubbers, piperylene rubber and dimethylbutadiene rubber; and silicone lubricants, contan a synergistic antioxidant composition which comprises (a) a phosphite ester of formula <FORM:0923190/IV(a)/1> wherein R1, R2 and R3 are alkyl, alkoxyalkyl, haloalkyl, cycloalkyl, halocycloalkyl, aralkyl, alkaryl, haloaryl or haloalkaryl radicals, and R3 may also be hydrogen, and (b) a methylene bisphenol of formula <FORM:0923190/IV(a)/2> wherein R4 is a C3-12- alkyl group which is branched on the a -carbon atom and R5 is a C1-12- alkyl group, the weight ratio (b) to (a) being 0,005-1000. In general the material to be stabilized contains 0,025-4% of (a) and 0,01-5%, preferably 0,1-3% of (b) by weight, there preferably being present 0,5-5 moles of (a) per mole of (b). (a) is most suitably a di-C1-12-alkyl hydrogen phosphite, and (b) is preferably 4:41-methylene bis(2:6-diisopropylphenol) or 4:41-methylene bis(6-tert.butyl-o-cresol).ALSO:A synergistic antioxidant composition for addition to material subject to oxidative deterioration comprises (a) a phosphite ester of formula <FORM:0923190/IV(a)/1> wherein R1, R2 and R3 are alkyl, alkoxyalkyl, haloalkyl, cycloalkyl, halocycloalkyl, aralkyl, alkaryl, haloaryl or haloalkaryl radicals, and R3 may also be hydrogen, and (b) a methylene bisphenol of formula <FORM:0923190/IV(a)/2> wherein R4 is a C3-12-alkyl group which is branched on the a -carbon atom and R5 is a C1-12-alkyl group, the weight ratio (b) to (a) being 0.005-1000. In general the material to be stabilized contains 0.025-4% of (a) and 0.01-5%, preferably 0.1-3% of (b) by weight, there preferably being present 0.0-5 moles of (a) per mole of (b). (a) is most suitably a di-C1-12-alkyl hydrogen phosphite, and (b) is preferably 4:41- methylene bis(2:6- diisopropylphenol) or 4:41-methylene bis(6-tert-.butylo-cresol). The compositions may be used to p stabilize vitamins A, D and E and certain of the B complex vitamins; halogen-containing compounds such as fluorocarbons; and phosphate esters of formula <FORM:0923190/IV(a)/3> where R, R1 and R11 are hydrogen or an organic radical at least one of the groups R, R1 and R11 being an organic radical, e.g. tricresyl phosphate.ALSO:Foodstuffs such as butter, margarine, potato chips, fried fish, doughnuts, crackers, cakes, biscuits, peanut butter, peanuts and other whole nuts, and salad dressings, fat-fortified animal feedstuffs and fish meal contain a synergistic antioxidant composition which comprises (a) a phosphite ester of formula <FORM:0923190/VI/1> wherein R1, R2 and R3 are alkyl, alkoxyalkyl, haloalkyl, cycloalkyl, halocycloalkyl, aralkyl, alkaryl, haloaryl or haloalkaryl radicals, and R3 may also be hydrogen, and (b) a methylene bisphenol of formula <FORM:0923190/VI/2> wherein R4 is a C3-12-alkyl group which is branched on the a -carbon atom and R5 is a C1-12-alkyl group, the weight ratio (b) to (a) being 0.005-1000. In general the material to be stabilized contains 0.025-4% of (a) and 0.01-5%, preferably 0.1-3% of (b) by weight, there preferably being present 0.5-5 mols. of (a) per mol. of (b). (a) is most suitably a di-C1-12-alkyl hydrogen phosphite, and (b) is preferably 4 : 41-methylene bis (2 : 6 - diisopropylphenol) or 4 : 41 - methylene bis (6-tert. butyl - o - cresol).