Lubricating Composition Including Esterified Copolymer And Low Dispersant Levels Suitable For Driveline Applications

Abstract

A lubricating composition, method of making, and method of use are disclosed. The lubricant includes an esterified copolymer including a backbone that includes units derived from a vinyl aliphatic monomer and units derived from a carboxylic acid monomer, the carboxylic acid monomer comprising an α,β-ethylenically unsaturated dicarboxylic acid or derivative thereof. The lubricating composition also includes an oil of lubricating viscosity. The lubricating composition includes no more than 2.5 wt. % of dispersant for dispersing oxidation products, other than the esterified copolymer.

1 . A lubricating composition comprising:
 a) an esterified copolymer with a backbone comprising units derived from a vinyl aliphatic monomer and units derived from a carboxylic acid monomer, the carboxylic acid monomer comprising an α,β-ethylenically unsaturated dicarboxylic acid or derivative thereof;   b) an oil of lubricating viscosity; and   wherein the lubricating composition comprises no more than 2.5 wt. % of dispersant for dispersing oxidation products, other than the esterified copolymer.   
     
     
         2 . The lubricating composition of  claim 1 , wherein the lubricating composition comprises no more than 2 wt. %, or no more than 1.75 wt. %, or no more than 1.5 wt. %, or no more than 1 wt. %, or no more than 0.5 wt. %, or no more than 0.2 wt. % or no more than 0.1 wt. % dispersant, other than the exemplary copolymer. 
     
     
         3 . The lubricating composition of  claim 1 , wherein the lubricating composition comprises dispersant, other than the exemplary copolymer, at 0.01-2.5 wt. %, or at 0.01-2 wt. %, or at 0.01-1.75 wt. %, or at 0.01-1.5 wt. %, or at 0.5-2.5 wt. %, or at 0.5-1.75 wt. %, or at 0.5-1.5 wt. %. 
     
     
         4 . The lubricating composition of  claim 1 , wherein the dispersant is present and consists essentially of a nitrogen-containing dispersant derived from an acylated C3-C6 polyalkylene compound. 
     
     
         5 . The lubricating composition of  claim 1 , wherein the esterified copolymer comprises a nitrogen-containing group. 
     
     
         6 . The lubricating composition of  claim 1 , wherein at least some of the units derived from the carboxylic acid monomer are at least one of aminated, amidated, and imidated with a nitrogen-containing compound. 
     
     
         7 . The lubricating composition of  claim 6 , wherein the nitrogen-containing compound is an amine-containing compound selected from the group consisting of morpholines, imidazolidinones, amino amides, β-alanine alkyl esters, aliphatic amines, aromatic amines, aliphatic polyamines, aromatic polyamines, and mixtures thereof. 
     
     
         8 . The lubricating composition of  claim 6 , wherein 0.1 to 25% of carboxylic acid functionalities of the units derived from the carboxylic acid monomer are at least one of aminated, amidated, and imidated with a nitrogen-containing compound. 
     
     
         9 . The lubricating composition of  claim 8 , wherein at least 1% of carboxylic acid functionalities on the units derived from the carboxylic acid monomer are reacted with a nitrogen-containing compound to provide a nitrogen-containing group. 
     
     
         10 . The lubricating composition of  claim 1 , wherein the esterified copolymer is substantially free of a nitrogen-containing group. 
     
     
         11 . The lubricating composition of  claim 10 , wherein the lubricating composition comprises no more than 2 wt. % dispersant, other than the exemplary copolymer. 
     
     
         12 . The lubricating composition of  claim 1 , wherein the esterified copolymer has a weight average molecular weight of 5,000-25,000. 
     
     
         13 . The lubricating composition of  claim 12 , wherein the esterified copolymer has a weight average molecular weight of 5000 to 10,000, or 15,000-25,000, or 10,000 to 17,000. 
     
     
         14 . The lubricating composition of  claim 1 , wherein the esterified copolymer is at least 5 wt. % of the lubricating composition. 
     
     
         15 . The lubricating composition of  claim 1 , wherein the esterified copolymer is at least 10 wt. %, or at least 40 wt. %, or at least 60 wt. % of the lubricating composition. 
     
     
         16 . The lubricating composition of  claim 1 , wherein the esterified copolymer is 30-60 wt. %, or 40-50 wt. % of the lubricating composition. 
     
     
         17 . The lubricating composition of  claim 1 , wherein the oil of lubricating viscosity is at least 20 wt. %, or at least 30 wt. % of the lubricating composition. 
     
     
         18 . The lubricating composition of  claim 1 , wherein the copolymer is esterified with a primary alcohol. 
     
     
         19 . The lubricating composition of  claim 18 , wherein the primary alcohol comprises a primary alcohol which is branched at the β- or higher position. 
     
     
         20 . The lubricating composition of  claim 18 , wherein the primary alcohol further comprises a linear primary alcohol. 
     
     
         21 . The lubricating composition of  claim 18 , wherein the primary alcohol comprises at least 6 carbon atoms. 
     
     
         22 . The lubricating composition of  claim 1 , wherein the carboxylic acid monomer comprises maleic anhydride. 
     
     
         23 . The lubricating composition of  claim 1 , wherein the vinyl aliphatic monomer comprises an alpha-olefin. 
     
     
         24 . The lubricating composition of  claim 23 , wherein the alpha-olefin comprises at least 6 carbon atoms. 
     
     
         25 . The lubricating composition of  claim 1 , wherein a molar ratio of the vinyl aliphatic monomer units to the carboxylic acid monomer units in the copolymer is from 1:3 to 3:1, or from 0.6:1 to 1.2:1, or from 0.7:1 to 1:1.1. 
     
     
         26 . The lubricating composition of  claim 1 , wherein the esterified copolymer backbone further comprises units derived from a vinyl aromatic monomer. 
     
     
         27 . The lubricating composition of  claim 26 , wherein a molar ratio of the units derived from the vinyl aromatic monomer to the units derived from the vinyl aliphatic monomer is from 0:100 to 25:75, or up to 10:90. 
     
     
         28 . The lubricating composition of  claim 1 , wherein the copolymer backbone comprises at least 20 of the units, or at least 100 of the units. 
     
     
         29 . The lubricating composition of  claim 1 , wherein the copolymer backbone comprises up to 1000 of the units, or up to 500 of the units, or up to 250 of the units derived from the vinyl aliphatic monomer and the carboxylic acid monomer. 
     
     
         30 . The lubricating composition of  claim 1 , further comprising at least one performance additive, other than the esterified copolymer. 
     
     
         31 . The lubricating composition of  claim 30 , wherein the at least one other performance additive comprises at least one of the group consisting of metal deactivators, detergents, viscosity index improvers, friction modifiers, corrosion inhibitors, antiwear agents, extreme pressure agents, antiscuffing agents, antioxidants, foam inhibitors, demulsifiers, pour point depressants, seal swelling agents, and mixtures thereof. 
     
     
         32 . The lubricating composition of  claim 31 , wherein the at least one other performance additive comprises an extreme pressure agent selected from the group consisting of dimercapto-1,3,4-thiadiazole, derivatives of dimercapto-1,3,4-thiadiazole, sulfurized olefins, and mixtures thereof. 
     
     
         33 . The lubricating composition of  claim 1 , wherein the lubricating composition comprises, in total, less than 2 wt. %, or less than 1.75 wt. %, or less than 1.5 wt. %, or less than 1 wt. %, or less than 0.5 wt. %, or less than 0.2 wt. % of dispersants selected from the group consisting of N-substituted long chain alkenyl succinimides, polyisobutylene succinimide complexed with zinc, Mannich bases, and post-treated dispersants formed by borating these compounds. 
     
     
         34 . The lubricating composition of  claim 1 , wherein the 20 hr KRL SSI of the lubricating composition is from 0-30, or from 0-10, or from 10-30. 
     
     
         35 . A process for preparing a lubricating composition comprising:
 (A) forming an esterified copolymer comprising:
 (1) reacting (i) a vinyl aliphatic monomer and (ii) a carboxylic acid monomer comprising an α,β-ethylenically unsaturated dicarboxylic acid or derivative thereof, to form a copolymer, wherein the carboxylic acid monomer optionally has ester groups, 
 (2) optionally, esterifying the copolymer of step (1) to form an esterified copolymer, and 
 (3) optionally, reacting the copolymer of step (1) or (2) with an nitrogen-containing compound in an amount to provide an esterified copolymer with at least 0.01 wt. % nitrogen; and 
 wherein the resulting copolymer is esterified in at least one of (1), (2), and (3); and 
   (B) mixing the esterified copolymer formed in (A) with at least one of an oil of lubricating viscosity and a performance additive other than the esterified copolymer, to provide a lubricating composition comprising no more than 2.5 wt. % of dispersant, other than the esterified copolymer, for dispersing oxidation products.   
     
     
         36 . The process of  claim 35 , comprising step (3). 
     
     
         37 . The process of  claim 35 , wherein the reacting of the esterified copolymer of step (1) or (2) with an nitrogen-containing compound provides the esterified copolymer with 0.01 wt. % to 1.5 wt. %, or 0.02 wt. % to 0.75 wt. %, or 0.04 wt. % to 0.25 wt. % nitrogen. 
     
     
         38 . The process of  claim 35 , comprising step (2). 
     
     
         39 . The process of  claim 35 , wherein the carboxylic acid monomer has ester groups derived from a primary alcohol to provide an esterified copolymer in step (1). 
     
     
         40 . A lubricating composition formed by the method of  claim 35 . 
     
     
         41 . (canceled) 
     
     
         42 . A method for lubricating a component of a driveline system of a vehicle comprising supplying the lubricating composition of  claim 1  to the component.