Lubricant composition
AssigneeExxon Research & Engineering Co.
InventorHarold Shaub
Life of this patent
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Abstract
An additive combination comprising a hydroxysubstituted ester of a polycarboxylic acid and a metal dihydrocarbyl dithiophosphate and lubricating compositions comprising the same. The lubricating compositions comprising these additives exhibit improved anti-friction and anti-wear properties. Best results are achieved when the ester is obtained from a dimer acid and particularly a dimer of a fatty acid containing conjugated unsaturation. The metal used in the metal dialkyl dithiophosphate must be one having a relatively soft metal oxide and particularly a metal oxide having a Mohs hardness of about 3 or less.
Claims14
A lubricating oil composition comprising a base oil, from about 0.01 to about 1.0 parts by weight of an hydroxy-substituted ester of a polycarboxylic acid with a glycol per 100 parts of base oil, said acid having a hydrocarbon portion containing from about 9 to about 42 carbon atoms between carboxyl groups and said glycol is selected from the group consisting of alkylene glycols having from about 2 to about 12 carbon atoms and polyalkylene glycols having from about 4 to about 200 carbon atoms and from about 0.01 to about 5.0 parts by weight, per 100 parts of base oil, of a metal dialkyl dithiophosphate, wherein the alkyl portion of said metal dialkyl dithiophosphate contains between about 1 and about 18 carbon atoms and said metal is a metal whose oxide exhibits a Mohs hardness of about 3.0 or less.
Dependencies are inferred from the claim text.