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AssigneeExxon Research & Engineering Co.
InventorsDavid L. Andrew, David A. Slack
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A grease composition comprises an effective amount of a lubricating oil containing an imide or pyrrolidone thickening agent or an imide or pyrrolidone thickening agent comprising a metal salt of a carboxylic acid in combination with a bimetal phthalate complexing agent, such as dilithium terephthalate. The presence of the complexing agent results in a grease having properties superior to that of a similar grease without the complexing agent. Preferred complexing agents are dimetal terephthalates in which the metal is an alkali or alkaline earth metal and is the same metal as is present in the thickener. An example is a combination of a calcium or lithium salt of the reaction product of trimellitic anhydride with a hydrogenated rapeseed amine and a dilithium terephthalate complexing agent.
A grease comprising an oil having lubricating quality and an effective amount of a thickening agent selected from the group consisting essentially of a pyrrolidone, an imide and mixture thereof, wherein if only a pyrrolidone is present it contains only one pyrrolidone group and is of the formula ##STR9## wherein if only an imide is present it is of the formula ##STR10## or a mixture of said imides, wherein R.sub.1 is a straight or branched chain alkyl or alkenyl group having from 6 to 30 carbon atoms and which may also contain one or more of N, O, S or P, wherein R.sub.2 is a hydrocarbyl group which may also contain one or more of N, O, S or P, wherein M is a Group I or II metal, wherein R.sub.1 and R.sub.2 are the same or different and wherein said grease contains at least one of said pyrrolidone or said imides defined above.
A grease comprising an oil having lubricating quality, an effective amount of a thickening agent selected from the group consisting essentially of a metal salt of a pyrrolidone, an imide and mixture thereof and a complexing agent which comprises at least one metal phthalate salt, wherein said pyrrolidone and imide comprise a metal salt of a carboxylic acid connected by a respective substituted pyrrolidone or imide linkage to an alkyl or alkenyl hydrocarbon chain which may contain one or more of N, O, S or P.
Dependencies are inferred from the claim text.