Mineral oil additive

A phosphorus sulphide or a mixture of phosphorus and sulphur is heated, e.g. at 200-500 DEG F. with (1) a polymer of a dicarboxylic acid ester of molecular weight between 1000 and 5000, derived from an a ,b -unsaturated dicarboxylic acid having 2 to 4 carbon atoms exclusive of the carboxyl groups and monohydric aliphatic alcohols, each containing 6 to 22 carbon atoms, the average number of carbon atoms in the alcohol radicals being 8 to 18, or copolymers of mixtures of such esters, or (2) a copolymer of at least 25 per cent of such an ester and a vinyl compound, where R is hydrogen or a methyl group and X is either a fatty acid radical with an alkyl group of 2 to 18 carbon atoms or an aromatic hydrocarbon radical having at least one alkyl side chain containing 1 to 4 carbon atoms, to give a lubricating oil additive. Examples of the acids are maleic, fumaric, glutaconic, itaconic, citraconic, mesaconic, a -methylene malonic and a -methylene glutaric acids and of the alcohols, n-hexyl, n-octyl, tert-octyl, 2-ethyl hexyl, n-dodecyl, and oleyl alcohols, and commercial mixtures of C10 to C18 primary alcohols derived from coconut oil. The copolymers may be those with vinyl acetate, propionate, butyrate, oleate, stearate, isopropenyl acetate, styrene, a -methyl styrene and vinyl naphthalene. The polymers may be prepared by mass or emulsion methods using catalysts, e.g. benzoyl or lauryl peroxide, cumene or t-butyl hydroperoxide, redox or Friedel-Crafts catalysts or clay. Sulphides of phosphorus, e.g. P2S3, P2S5, P4S3, P4S7 or mixtures or elemental powdered sulphur and white phosphorus may be used in an inert solvent, e.g. benzene, o-dichlorobenzene, or mineral oils. The compounds may be used as additives directly or as the metal salts of, for example, calcium or barium, prepared by heating with metallic oxides or hydroxides at 50-400 DEG F. Examples describe the preparation of an oleyl-coconut oil alcohol fumarate copolymer, an oleyl itaconate polymer, a coconut oil alcohol fumarate polymer, a coconut oil alcohol maleate-vinyl acetate copolymer in a mineral oil solvent and a coconut oil alcohol fumarate - styrene copolymer in a n-heptane solvent, which are heated with P2S5.ALSO:Lubricating oil additives comprise the reaction product of phosphorus sulphide or a mixture of phosphorus and sulphur with (1) a polymer of a dicarboxylic acid ester of molecular weight between 1,000 and 50,000, derived from a carboxylic acid with a double bond in a