Abstract:
A mineral lubricating oil composition (see Group III) comprises minor proportions of (a) a metal salt of a thiophosphoric acid ester, (b) an oil soluble alkaline earth metal sulphonate and (c) an oil soluble alkaline earthmetal- and sulphur-containing, permanently thermoplastic, resinous condensation product of formaldehyde, a metal sulphide and an alkylated monohydric phenol. Ingredient (c) may be prepared by reacting together formaldehyde, alkylated monohydric phenol or naphthol and alkali metal sulphide or alkaline earth metal sulphide, with or without alkali metal hydroxide or alkaline earth metal hydroxide (the product, wherever an alkali metal compound is used, being subsequently treated with a water-soluble salt of an alkaline earth metal to form the alkaline earth metal compound by metathesis). Alternatively, the metal sulphide (with or without hydroxide) may be first reacted with the phenol or formaldehyde and then reacted with the other reactant. In the Examples, the preparation of a calcium or sodium sulphide/formaldehyde/iso-octyl phenol condensation product is described. In the case of the product obtained with the aid of sodium sulphide, the product is after-treated with barium chloride.ALSO:A lubricating oil composition (see Group III) includes, as ingredients thereof, (a) calcium petroleum sulphonate and (b) a metal salt of a thiophosphoric acid ester. The calcium petroleum sulphonate (a) may be prepared by heating sodium petroleum sulphonate with aqueous calcium chloride, driving off the water, adding a little hydrated lime, diluting with mineral oil and filtering. The metal thiophosphates (b) may be Group II metal (or aluminium or tin) salts of alkyl or cycloalkyl esters of monoor di-thiophosphoric acids, including the mixed zinc-alkaline earth metal (Ca,Ba,Sr) salts. In an example, mixed zinc-calcium salts of oxooctyl esters of thiophosphoric acids are prepared by reacting oxo-octyl alcohols with P2S5 and treating the reaction product first with zinc oxide and then with hydrated lime (in the presence of benzoyl peroxide). The use of zinc instead of zinc oxide is mentioned.ALSO:A lubricating composition comprises a major proportion of a mineral lubricating oil and a minor proportion of each of (a) a metal salt of a thiophosphoric acid ester, (b) an oilsoluble alkaline earth metal sulphonate and (c) an oil-soluble alkaline-earth-metal- and sulphur - containing, permanently thermoplastic, resinous condensation product of formaldehyde, a metal sulphide and an alkylated monohydric phenol. The composition may contain additional ingredients such as other oxidation inhibitors (e.g. 2,4,6-tri-tert. butyl-phenol and 2,6-di-tert. butyl-4-methyl phenol), viscosity index improvers (e.g. polymerized acrylate esters), foam inhibitors (e.g. silicone polymers) and dyes. Ingredient (a) may comprise Group II metal (or aluminium or tin) salts of alkyl or cycloalkyl esters of mono- or di-thiophosphoric acids, including mixed zinc-alkaline earth metal salts. Ingredient (b) may be a petroleum sulphonate, an alkaryl sulphonate or the salt of a sulphonate obtained by the sulphonation of organic acids such as naphthenic or fatty acids. Ingredient (c) may be prepared by reacting together formaldehyde, alkylated monohydric phenol or naphthol and alkali metal sulphide or alkaline earth metal sulphide, with or without alkali metal hydroxide or alkaline earth metal hydroxide (the product, wherever an alkali metal compound is employed, being subsequently treated with a water-soluble salt of an alkaline earth metal to form the alkaline earth metal compound by metathesis). Alternatively, the metal sulphide (with or without hydroxide) may be first reacted with the phenol or formaldehyde and then reacted with the other reactant. In the examples, mineral lubricating oil compositions are described wherein ingredient (a) is zinc di-cyclohexyl dithiophosphate or mixed zinc-calcium oxo-octyl thiophosphate, ingredient (b) is calcium or barium petroleum sulphonate and ingredient (c) is a calcium sulphide/formaldehyde/iso-octyl phenol condensation product or a material obtained by treating a sodium sulphide/formaldehyde/isooctyl phenol condensation product with barium chloride.