Alkyl (meth) acrylate copolymers

Abstract

Alkyl (meth) acrylate copolymers comprising from about 10 to about 23 weight percent C 3 -C 7 alkyl (meth) acrylate; from about 77 to about 90 weight percent C 12 -C 14 alkyl (meth) acrylate(s); and from 0 to about 6 weight percent of at least one C 6 -C 20 alkyl (meth) acrylate, which provide excellent low temperature properties and shear stability to lubricating oils. The preferred embodiment comprises butyl (meth) acrylate as the C 3 -C 7 alkyl (meth) acrylate, and is essentially free from methyl (meth) acrylate.

I claim:  
     
         1 . An alkyl (meth) acrylate copolymer comprising: 
 (A) about 10 to about 23 weight percent of at least one C 3 -C 7  alkyl (meth) acrylate;    (B) about 77 to about 90 weight percent of at least one C 12 -C 14  alkyl (meth) acrylate; and    (C) 0 to about 6 weight percent of at least one C 16 -C 20  alkyl (meth) acrylate.    
     
     
         2 . An alkyl (meth) acrylate copolymer product obtained by combining components comprising: 
 (A) from about 10 to about 23 weight percent of at least one C 3 -C 7  alkyl (meth) acrylate;    (B) from about 77 to about 90 weight percent of at least one C 12 -C 14  alkyl (meth) acrylate; and    (C) 0 to about 6 weight percent of at least one C 16 -C 20  alkyl (meth) acrylate.    
     
     
         3 . The copolymer of  claim 1  or  claim 2 , wherein the copolymer is essentially free from methyl (meth) acrylate units.  
     
     
         4 . The copolymer of  claim 1  or  claim 2 , wherein the C 3 -C 7  alkyl (meth) acrylate is butyl (meth) acrylate.  
     
     
         5 . The copolymer of  claim 1  or  claim 2 , wherein the copolymer has an average molecular weight number from about 5,000 to about 50,000.  
     
     
         6 . A method for making a lubricating oil, comprising adding to an oil of lubricating viscosity a copolymer according to  claim 1  or  claim 2 .  
     
     
         7 . A lubricating oil composition comprising: 
 (A) an oil of lubricating viscosity; and    (B) a copolymer according to  claim 1  or  claim 2 .    
     
     
         8 . The lubricating oil composition of  claim 7 , wherein the C 3 -C 7  alkyl (meth) acrylate is butyl (meth) acrylate.  
     
     
         9 . The lubricating oil composition of  claim 7 , wherein the composition is essentially free from methyl (meth) acrylate units.  
     
     
         10 . The lubricating oil composition of  claim 7 , wherein component (B) is present in an amount of from 1 to about 30 parts by weight of active copolymer per 100 parts by weight of oil in a final composition.  
     
     
         11 . The lubricating oil composition of  claim 7  further comprising at least one additive selected from the group consisting of oxidation inhibitors, corrosion inhibitors, friction modifiers, antiwear agents, extreme pressure agents, detergents, dispersants, antifoamants, additional viscosity index improvers, and pour point depressants.  
     
     
         12 . A method for improving the low temperature properties of an oil, said method comprising adding to an oil of lubricating viscosity a copolymer according to  claim 1  or  claim 2 .  
     
     
         13 . A method for improving the compatibility of a lubricating oil containing additive components, said method comprising adding to an oil of lubricating viscosity at least one additive component, and a copolymer according to  claim 1  or  claim 2 .  
     
     
         14 . A method for improving the viscosity index of a lubricating oil, said method comprising adding to an oil of lubricating viscosity a copolymer according to  claim 1  or  claim 2 .  
     
     
         15 . A gear lubricant composition comprising: 
 (A) an oil of lubricating viscosity; and    (B) a copolymer according to  claim 1  or  claim 2 .    
     
     
         16 . The gear lubricant composition of  claim 15 , wherein the C 3 -C 7  alkyl (meth) acrylate is butyl (meth) acrylate.  
     
     
         17 . The gear lubricant composition of  claim 15 , wherein the copolymer is essentially free from methyl (meth) acrylate.  
     
     
         18 . The gear lubricant composition of  claim 15 , wherein component (B) is present in an amount of 1 to about 30 by weight of active copolymer by weight in said gear lubricant composition.  
     
     
         19 . A composition for an automatic transmission fluid comprising: 
 (A) an oil of lubricating viscosity;    (B) a copolymer according to  claim 1  or  claim 2;  and    (C) at least one additive selected from the group consisting of oxidation inhibitors, corrosion inhibitors, friction modifiers, antiwear agents, extreme pressure agents, detergents, dispersants, antifoamants, viscosity index improvers, and pour point depressants.    
     
     
         20 . A method for lubricating a continuously variable transmission, comprising applying thereto the composition of  claim 19 .  
     
     
         21 . The composition of  claim 19 , wherein the automatic transmission fluid has a percent shear stability index, as determined by the 20 hour Tapered Bearing Shear Test, in the range of 1% to about 80%.  
     
     
         22 . The composition of  claim 19 , wherein said automatic transmission fluid has a percent shear stability index, as determined by the 20 hour Tapered Bearing Shear Test, in the range of 1% to 20%.  
     
     
         23 . The composition of  claim 19 , wherein the transmission fluid is a continuously variable transmission fluid.  
     
     
         25 . A vehicle comprising an automatic transmission lubricated with the composition of  claim 19 .  
     
     
         25 . An automatic transmission lubricated with the composition of  claim 19 .  
     
     
         26 . The automatic transmission of  claim 25 , wherein the transmission is a continuously variable transmission.  
     
     
         27 . The copolymer of  claim 1 , wherein component (A) is present in an amount of about 11 to about 18 weight percent.  
     
     
         28 . The copolymer of  claim 1 , wherein component (A) is present in an amount of about 12 to about 13 weight percent.