Supplemental rust inhibitors and rust inhibition in internal combustion engines
AssigneeEthyl Corporation
InventorJohn G. Schaffhausen
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Abstract
An esterification product obtained by reacting ethylene oxide/propylene oxide block copolymer with a long-chain monocarboxylic acid, when employed as a supplemental rust inhibitor in lubricating oils for internal combustion engines, has been found to furnish excellent rust inhibition in the engines and to be compatible with other components in the lubricating oils. A lubricating oil composition containing such product may be used to inhibit rust formation in an internal combustion engine.
Claims18
A lubricating oil composition comprising a major amount of a hydrocarbon oil of lubricating viscosity, a minor amount of a dispersant, a minor amount of a primary rust inhibitor, and from about 0.03% to about 1 wt. %, based on the weight of the oil composition, of an esterification product having a total acid number (TAN) that is in the range of about 10 to about 40 and being prepared by reacting in the presence of a catalyst and at a temperature in the range of about 25.degree. C. (77.degree. F.) to about 111.degree. C. (232.degree. F.) ethylene oxide/propylene oxide block copolymer with a long-chain monocarboxylic acid having an alkyl radical with sufficient carbon atoms to provide solubility of said product in said composition.
A method for operating an internal combustion engine to inhibit rust formation, which method comprises lubricating said engine with a lubricating oil composition comprising a major amount of a hydrocarbon oil of lubricating viscosity, a minor amount of a dispersant, a minor amount of a primary rust inhibitor, and from about 0.03% to about 1 wt. % based on the weight of the oil composition of a compatible lubricating oil supplemental rust inhibitor consisting essentially of a reaction product having a total acid number (TAN) that is in the range of about 10 to about 40 of a nonionic polyol ether ethylene oxide/propylene oxide block copolymer of a molecular weight of from about 2000 to about 3000, which is borderline water dispersible to water insoluble, with a long-chain monocarboxylic acid having an alkyl radical with sufficient carbon atoms to provide solubility of said product in said composition.
Dependencies are inferred from the claim text.