Gear oil compositions

Abstract

A gear oil composition, a method for operating an automotive gear, and a method for improving performance of a gear oil that includes a) a major amount of a base oil having a lubricating viscosity; b) a polysulfide extreme pressure agent; and c) a reaction product of an acylated copolymer and a polyamine.

1 . A gear oil composition comprising:
 a) a major amount of a base oil having a lubricating viscosity;   b) a polysulfide extreme pressure agent; and   c) a reaction product of an acylated copolymer and a polyamine.   
     
     
         2 . The gear oil of  claim 1 , wherein the reaction product of an acylated copolymer and a polyamine comprises an acylated olefin copolymer reacted with N-phenyl-1,4-phenylenediamine (NPPDA), wherein the acylated olefin copolymer has grafted thereon from 0.3 to 0.75 carboxylic groups per 1000 number average molecular weight units of olefin copolymer and wherein the olefin copolymer has a number average molecular weight of between about 40,000 and 150,000. 
     
     
         3 . The gear oil of  claim 1 , wherein the reaction product of an acylated copolymer and a polyamine comprises an acylated olefin copolymer reacted with 4-anilino-4′-nitroazobenzene, wherein the acylated olefin copolymer has grafted thereon from 0.3 to 0.75 carboxylic groups per 1000 number average molecular weight units of olefin copolymer and wherein the olefin copolymer has a number average molecular weight of between about 40,000 and 150,000. 
     
     
         4 . The gear oil of  claim 1 , wherein the reaction product of an acylated copolymer and a polyamine comprises an acylated olefin copolymer reacted with 4-4-nitrophenyl azoaniline, wherein the acylated olefin copolymer has grafted thereon from 0.3 to 0.75 carboxylic groups per 1000 number average molecular weight units of olefin copolymer and wherein the olefin copolymer has a number average molecular weight of between about 40,000 and 150,000. 
     
     
         5 . The gear oil of  claim 1 , wherein the polysulfide comprises an alkyl polysulfide. 
     
     
         6 . The gear oil of  claim 5  wherein the polysulfide is selected from the group consisting of dicyclohexyl polysulfide, diphenyl polysulfide, dibenzyl polysulfide, dinonyl polysulfide, and mixtures of di-t-butyl polysulfides. 
     
     
         7 . The gear oil of  claim 1 , wherein the polysulfide component is present in the gear oil in an amount ranging from about 2.0 to about 3.3 wt. % based on a total weight of the gear oil. 
     
     
         8 . The gear oil of  claim 1 , wherein the reaction product of acylated olefin copolymer and polyamine component is present in the gear oil in an amount ranging from greater than about 1.0 wt. % to less than about 3.0 wt. % based on a total weight of the gear oil. 
     
     
         9 . A gear oil additive concentrate comprising a polysulfide extreme pressure agent and a reaction product of an acylated copolymer and a polyamine, wherein a weight ratio of reaction product to polysulfide in the additive concentrate ranges from about 0.3:1 to about 1.5:1 and the additive package comprises from about 40 to about 60 wt. % of the polysulfide. 
     
     
         10 . The additive concentrate of  claim 9 , wherein the reaction product of an acylated copolymer and a polyamine comprises an acylated olefin copolymer reacted with N-phenyl-1,4-phenylenediamine (NPPDA), wherein the acylated olefin copolymer has grafted thereon from 0.3 to 0.75 carboxylic groups per 1000 number average molecular weight units of olefin copolymer and wherein the olefin copolymer has a number average molecular weight of between about 40,000 and 150,000. 
     
     
         11 . The additive concentrate of  claim 9 , wherein the reaction product of an acylated copolymer and a polyamine comprises an acylated olefin copolymer reacted with 4-anilino-4′-nitroazobenzene, wherein the acylated olefin copolymer has grafted thereon from 0.3 to 0.75 carboxylic groups per 1000 number average molecular weight units of olefin copolymer and wherein the olefin copolymer has a number average molecular weight of between about 40,000 and 150,000. 
     
     
         12 . The additive concentrate of  claim 9 , wherein the reaction product of an acylated copolymer and a polyamine comprises an acylated olefin copolymer reacted with 4-4-nitrophenyl azoaniline, wherein the acylated olefin copolymer has grafted thereon from 0.3 to 0.75 carboxylic groups per 1000 number average molecular weight units of olefin copolymer and wherein the olefin copolymer has a number average molecular weight of between about 40,000 and 150,000. 
     
     
         13 . The additive concentrate of  claim 9 , wherein the polysulfide comprises an alkyl polysulfide. 
     
     
         14 . The additive concentrate of  claim 13 , wherein the polysulfide is selected from the group consisting of dicyclohexyl polysulfide, diphenyl polysulfide, dibenzyl polysulfide, dinonyl polysulfide, and mixtures of di-t-butyl polysulfides. 
     
     
         15 . A method for lubricating an automotive gear comprising:
 supplying to an automotive gear, a gear oil comprising:
 a) a major amount of base oil; 
 b) a polysulfide extreme pressure agent; and 
 c) a reaction product of an acylated olefin copolymer and a polyamine; 
   and operating a vehicle containing the automotive gear to lubricate the gear.   
     
     
         16 . A method for improving the performance of a gear oil made with less than 100 wt. % bright stock base oil, comprising formulating the gear oil with a major amount of base oil and an additive mixture comprising (i) a polysulfide extreme pressure agent and (ii) a reaction product of an acylated olefin copolymer and a polyamine.