Perfectionnements aux compositions lubrifiantes

A lubricating composition, suitable for use in internal combustion engines, comprises (1) a lubricating oil; (2) an additive obtained by the reaction of an alkylene oxide with the acid product of the reaction of a phosphorus sulphide with a hydrocarbon; and (3) an additive obtained either by the polymerization (or copolymerization with one or more polymerizable organic compounds) of the ester of an unsaturated organic acid and an ether alcohol formed by the reaction of an alkylene oxide with an aliphatic alcohol, or by the polymerization (or copolymerization with one or more polymerizable organic compounds) of the product of the reaction of an alkylene oxide with a partial ester of an unsaturated polycarboxylic acid and an aliphatic alcohol. The lubricating oil may be animal, vegetable, mineral or synthetic. Additive (2) may be prepared as described in Specification 792,553, while additive (3) may be prepared as described in Specification 788,129. The lubricating composition may also contain detergents, agents for lowering the solidification point, viscosity index improvers, colouring matter and anti-froth agents. In the examples, mineral lubricating oil compositions are described in which additive (2) is a reaction product of ethylene oxide with P2S5-treated polyisobutylene and additive (3) is obtained by partially esterifying maleic anhydride with C9 oxo alcohol, reacting the partial ester with ethylene oxide and copolymerizing the reaction product with a maleic diester of a C9 oxo alcohol, a maleic diester of a C17 oxo alcohol and vinyl acetate. The effect of omitting either additive (2) or additive (3) is described.