Dispersant Viscosity Index Improver-Containing Lubricant Compositions and Methods of Use Thereof

Abstract

Lubricating oil compositions and methods of their use are provided herein. A lubricating oil composition as described herein includes a major amount of an oil of lubricating viscosity, an amine-functionalized olefin copolymer dispersant viscosity index improver in an amount of from about 1.5 wt. % to 2.0 wt. % based on the weight of the lubricating oil composition, and a dispersant. The amine-functionalized olefin copolymer dispersant viscosity index improver includes a reaction product of an acylated olefin copolymer and a polyamine. The dispersant includes reaction product of components (A) a hydrocarbyl-dicarboxylic acid or anhydride having a number average molecular weight of from about 500 to about 5000 and (B) at least one polyamine, wherein the reaction product is post-treated with (C) an aromatic carboxylic acid, an aromatic polycarboxylic acid, or an aromatic anhydride, wherein all carboxylic acid or anhydride groups are attached directly to an aromatic ring, and/or (D) a non-aromatic dicarboxylic acid or anhydride having a number average molecular weight of less than about 500.

1 . A lubricating oil composition, comprising:
 a major amount of an oil of lubricating viscosity;   an amine-functionalized olefin copolymer dispersant viscosity index improver comprising a reaction product of an acylated olefin copolymer and a polyamine in an amount of from about 1.5 wt. % to about 2.0 wt. % based on the weight of the lubricating oil composition; and   a dispersant comprising a reaction product of components (A) a hydrocarbyl-dicarboxylic acid or anhydride having a number average molecular weight of from about 500 to about 5000 and (B) at least one polyamine, wherein the reaction product is post-treated with (C) an aromatic carboxylic acid, an aromatic polycarboxylic acid, or an aromatic anhydride, wherein all carboxylic acid or anhydride groups are attached directly to an aromatic ring, and/or (D) a non-aromatic dicarboxylic acid or anhydride having a number average molecular weight of less than about 500, wherein the dispersant is present in an amount of from about 4 wt. % to about 5.5 wt %.   
     
     
         2 . The lubricating oil composition of  claim 1 , wherein the amine-functionalized olefin copolymer dispersant viscosity index improver comprises an olefin copolymer having grafted thereon from 0.3 to 0.75 carboxylic groups per 1000 number average molecular weight units of olefin copolymer. 
     
     
         3 . The lubricating oil composition of  claim 2 , wherein the olefin copolymer has a number average molecular weight of between about 40,000 and about 150,000. 
     
     
         4 . The lubricating oil composition of  claim 2 , wherein the olefin copolymer is a copolymer of ethylene and one or more C 3 -C 23  alpha-olefins. 
     
     
         5 . The lubricating oil composition of  claim 1  comprising about 1.8 wt. % of the amine-functionalized olefin copolymer dispersant viscosity index improver. 
     
     
         6 . (canceled) 
     
     
         7 . The lubricating oil composition of  claim 1 , wherein the dispersant is present in an amount of from about 5 wt. % to about 5.5 wt. %. 
     
     
         8 . The lubricating oil composition of  claim 1 , wherein component (A) comprises a polyalkenyl-substituted succinic acid or anhydride. 
     
     
         9 . The lubricating oil composition of  claim 1 , wherein component (C) comprises 1,8-naphthalic anhydride. 
     
     
         10 . The lubricating oil composition of  claim 1 , wherein component (D) comprises maleic anhydride. 
     
     
         11 . The lubricating oil composition of  claim 1 , wherein from about 0.25 to 1.5 moles of component (C) is reacted per mole of component (B). 
     
     
         12 . The lubricating oil composition of  claim 1 , wherein from about 0.25 to 1.5 moles of component (D) is reacted per mole of component (B). 
     
     
         13 . The lubricating oil composition of  claim 1 , wherein the oil of lubricating viscosity comprises a Group II oil. 
     
     
         14 . The lubricating oil composition of  claim 1 , wherein the oil of lubricating viscosity meets the specification of a SAE 10W-30 engine oil. 
     
     
         15 . The lubricating oil composition of  claim 1 , wherein the oil of lubricating viscosity meets the specification of a SAE 15W-40 engine oil. 
     
     
         16 . The lubricant composition of  claim 1 , wherein the dispersant is a reaction product of A and B, post-treated with both C and D. 
     
     
         17 . The lubricating oil composition of  claim 1 , further comprising a metal-containing detergent. 
     
     
         18 . The lubricating oil composition of  claim 1 , further comprising an additional dispersant. 
     
     
         19 . The lubricating oil composition of  claim 18 , wherein the additional dispersant comprises one or more polyalkenyl succinimide dispersants. 
     
     
         20 . The lubricating oil composition of  claim 1 , wherein the lubricating oil composition is a heavy duty engine oil composition. 
     
     
         21 . A method of lubricating an engine, comprising:
 supplying to an engine the lubricating oil composition according to  claim 1 .   
     
     
         22 . A method of controlling soot induced viscosity increase in an engine lubricant, comprising:
 lubricating an engine with the lubricating oil composition according to  claim 1 .   
     
     
         23 . A method of reducing oil mist separator filter plugging in an engine, comprising:
 lubricating an engine with the lubricating oil composition according to  claim 1 .   
     
     
         24 . An additive composition, comprising:
 an amine-functionalized olefin copolymer dispersant viscosity index improver comprising a reaction product of an acylated olefin copolymer and a polyamine in an amount of from about 8 wt. % to about 12 wt. % based on the weight of the additive composition; and   a dispersant comprising a reaction product of components (A) a hydrocarbyl-dicarboxylic acid or anhydride having a number average molecular weight of from about 500 to about 5000 and (B) at least one polyamine, wherein the reaction product is post-treated with (C) an aromatic carboxylic acid, an aromatic polycarboxylic acid, or an aromatic anhydride wherein all carboxylic acid or anhydride groups are attached directly to an aromatic ring, and/or (D) a non-aromatic dicarboxylic acid or anhydride having a number average molecular weight of less than about 500, wherein the dispersant is present in an amount of from about 10 wt. % to about 20 wt. %.   
     
     
         25 . The additive composition of  claim 24 , wherein the amine-functionalized olefin copolymer dispersant viscosity index improver is present in an amount of from about 9 wt. % to about 11 wt. % based on the weight of the additive composition. 
     
     
         26 . The additive composition of  claim 24 , wherein the weight ratio of the dispersant to the amine-functionalized olefin copolymer dispersant viscosity index improver is from about 1.5:1 to about 3:1. 
     
     
         27 . The additive composition of  claim 24 , wherein the weight ratio of the dispersant to the amine-functionalized olefin copolymer dispersant viscosity index improver is from about 2:1 to about 3:1. 
     
     
         28 . The additive composition of  claim 24 , wherein the weight ratio of the dispersant to the amine-functionalized olefin copolymer dispersant viscosity index improver is from about 2.7:1 to about 3:1. 
     
     
         29 . (canceled) 
     
     
         30 . The additive composition of  claim 24 , wherein the dispersant is present in an amount of from about 10 wt. % to about 12 wt. %.