Lubricants containing olefin copolymer and acrylate copolymer

Abstract

A lubricating oil composition comprising an oil of lubricating viscosity and a total of from about 1 to about 50% by weight of copolymers comprising (A) at least one ethylene-aliphatic olefin copolymer wherein the aliphatic olefins contain from 3 to about 24 carbon atoms, said copolymer (A) having {overscore (M)} n ranging from about 600 to about 5000, and (B) at least one copolymer comprising units derived from alkyl acrylate ester monomers containing from 2 to about 25 carbon atoms in the ester group, and optionally, from about 0.1% to about 20% by weight of at least one member of the group consisting of vinyl aromatic monomers and nitrogen-containing vinyl monomers. said copolymer (B) having {overscore (M)} n ranging from about 10,000 to about 350,000, wherein the weight ratio of (A):(B) ranges from about 99:1 to about 1:99.

What is claimed is:  
     
         1 . A lubricating oil composition comprising an oil of lubricating viscosity and a total of from about 1 to about 50% by weight of copolymers comprising 
 (A) at least one ethylene-aliphatic olefin copolymer wherein the aliphatic olefins contain from 3 to about 24 carbon atoms, said copolymer (A) having {overscore (M)} n  ranging from about 600 to about 5000; and    (B) at least one copolymer comprising units derived from alkyl acrylate ester monomers containing from 2 to about 25 carbon atoms in the ester group, and optionally, from about 0.1% to about 20% by weight of units derived at least one member of the group consisting of vinyl aromatic monomers and nitrogen-containing vinyl monomers, said copolymer (B) having {overscore (M)} n  ranging from about 10,000 to about 350,000;    wherein the weight ratio of (A):(B) ranges from about 99:1 to about 1:99.    
     
     
         2 . The lubricating oil composition of  claim 1  wherein copolymer (A) comprises an ethylene-alpha olefin copolymer wherein the ethylene content ranges from about 30 mole % to about 85 mole %.  
     
     
         3 . The lubricating oil composition of  claim 2  wherein the ethylene content ranges from about 45 to about 55 mole %.  
     
     
         4 . The lubricating oil composition of  claim 2  wherein (A) is an ethylene-propylene copolymer wherein the ethylene content ranges from about 40 mole % to about 85 mole %.  
     
     
         5 . The lubricating oil composition of  claim 4  wherein. the ethylene content ranges from about 45 to about 55 mole %.  
     
     
         6 . The lubricating composition of  claim 1  wherein copolymer (B) comprises units derived from monomers comprising from about 5% to about 75% by weight of alkyl acrylate ester monomers containing from 2 to 12 carbon atoms in the ester group and from about 25% to about 95% by weight of alkyl acrylate ester monomers containing from 13 to about 25 carbon atoms in the ester group.  
     
     
         7 . The lubricating oil composition of  claim 1  wherein copolymer (B) comprises units derived from 
 (a) about 35 mole % to about 95 mole % of alkyl methacrylate ester monomers containing from about 9 to about 25 carbon atoms in the ester group and  
 (b) about 65 mole % to about 5 mole % of alkyl methacrylate ester monomers containing from about 7 to about 12 carbon atoms in the ester group, and optionally  
 (c) from about 0.1 mole % to about 20 mole % of at least one member of the group consisting of alkyl methacrylate ester monomers containing from 2 to about 8 carbon atoms in the ester group, which esters are different from methacrylate esters (a) and (b), vinyl aromatic monomers and nitrogen-containing vinyl monomers, with the proviso that no more than 60% by weight of the esters contain not more than 11 carbon atoms in the ester group.  
 
     
     
         8 . The lubricating oil composition of  claim 7  wherein the alkyl moieties of the ester groups of alkyl methacrylate ester monomer (b) have 2-(C 1-4  alkyl) substituents.  
     
     
         9 . The lubricating oil composition of  claim 1  wherein copolymer (B) comprises units derived from 
 (a) about 35 mole % to about 95 mole % of alkyl methacrylate ester monomers containing from about 13 to about 25 carbon atoms in the ester group and  
 (b) about 65 mole % to about 5 mole % of alkyl methacrylate ester monomers containing from about 7 to about 12 carbon atoms in the ester group.  
 
     
     
         10 . The composition of  claim 9  wherein copolymer (B) further comprises from about 0.1 mole % to about 20 mole % of units derived from (c) at least one member of the group consisting of alkyl methacrylate ester monomers containing from 2 to about 8 carbon atoms in the ester group, which esters are different from methacrylate esters (a) and (b), vinyl aromatic monomers and nitrogen-containing vinyl monomers, with the proviso that no more than 60% by weight of the esters contain not more than 11 carbon atoms in the ester group.  
     
     
         11 . The lubricating oil composition of  claim 9  wherein the alkyl moieties of the ester groups of alkyl methacrylate ester monomer (b) have 2-(C 1-4  alkyl) substituents.  
     
     
         12 . The lubricating oil composition of  claim 11  wherein monomer (b) comprises 2-ethylhexyl methacrylate.  
     
     
         13 . The lubricating oil composition of  claim 1  wherein 
 (A) is an ethylene-alpha olefin copolymer wherein the ethylene content ranges from about 30 mole % to about 85 mole %; and  
 (B) is a polymethacrylate copolymer comprising units derived from 
 (a) about 35 mole % to about 95 mole % of alkyl methacrylate ester monomers containing from about 9 to about 25 carbon atoms in the ester group and  
 (b) about 65 mole % to about 5 mole % of alkyl methacrylate ester monomers containing from about 7 to about 12 carbon atoms in the ester group, and optionally  
 (c) about 0.2 mole % to about 10 mole % of at least one member of the group consisting of alkyl methacrylate ester monomers containing from 2 to about 8 carbon atoms in the ester group, which esters are different from methacrylate esters (a) and (b), vinyl aromatic monomers and nitrogen-containing vinyl monomers, with the proviso that no more than 60% by weight of the esters contain not more than 11 carbon atoms in the ester group,  
 wherein the weight ratio (A):(B) ranges from about 25:75 to about 75:25.  
 
 
     
     
         14 . The lubricating oil composition of  claim 13  wherein the alkyl moieties of the ester groups of alkyl methacrylate monomer (b) have 2-(C 1-4  alkyl) substituents.  
     
     
         15 . The lubricating oil composition of  claim 1  wherein (B) further comprises units derived from about 0.1% to about 10% by weight of at least one nitrogen containing vinyl monomer.  
     
     
         16 . The lubricating oil composition of  claim 1  wherein (B) is a copolymer prepared by a process comprising reacting, in the presence of a free radical initiator 
 (1) from about 55% to about 99.9% by weight of one or more alkyl acrylate ester monomers containing from 2 to about 25 carbon atoms in the ester group, wherein at least about 50 mole % of the esters contain at least 6 carbon atoms in the ester group, and  
 (2) from about 0.1% to about 45% by weight of at least one monomer selected from the group consisting of acrylic acid esters containing from 2 to about 8 carbon atoms in the ester group and which are different from alkyl acrylate ester monomers (1), vinyl aromatic monomers and nitrogen-containing vinyl monomers, with the proviso that no more than 60% by weight of the esters contain not more than 11 carbon atoms in the ester group, and optionally, in the presence of a chain transfer agent, wherein monomer (1), the free radical initiator, and if used, the chain transfer agent, are first combined to form a mixture, whereupon from about 10% to about 80% of said mixture is mixed with monomer (2) to form a second mixture; from about 20% to about 100% of the mixture of monomers (1) and (2) is heated until an exotherm is noted, then while maintaining reaction temperature, first adding the balance, if any, of the mixture of monomers (1) and (2) over about 0.25 hour to about 5 hours followed by addition over 0.25 to about 5 hours of the remaining mixture of monomer (1) and initiator, optionally adding additional initiator, whereupon the reaction is continued to completion.  
 
     
     
         17 . The lubricating oil composition of  claim 16  wherein monomer (2) comprises a nitrogen containing vinyl monomer.  
     
     
         18 . The lubricating oil composition of  claim 17  wherein the nitrogen containing vinyl monomer is selected from the group consisting of vinyl substituted nitrogen heterocyclic monomers, dialkylaminoalkyl acrylate monomers, dialkylaminoalkyl acrylamide monomers, N-tertiary alkyl acrylamides, and vinyl substituted amines.  
     
     
         19 . The lubricating oil composition of  claim 10  wherein (B) is prepared by a process comprising reacting, in the presence of a free radical initiator 
 (a) the methacrylic acid esters containing from about 13 to about 25 carbon atoms in the ester group, and  
 (b) the methacrylic acid esters containing from 7 to about 12 carbon atoms in the ester group, and  
 (c) the at least one monomer selected from the group consisting of methacrylic acid esters containing from 2 to about 8 carbon atoms in the ester group and which are different from methacrylic acid esters (a) and (b), vinyl aromatic monomers and nitrogen-containing vinyl monomers, with the proviso that no more than 60% by weight of the esters contain not more than 11 carbon atoms in the ester group, optionally in the presence of a chain transfer agent, wherein monomers (a) and (b), the free radical initiator, and if used, the chain transfer agent, are combined to prepare a first mixture; from about 10% to about 80% by weight of the first mixture of monomers (a) and (b) is combined with monomer (c) to prepare a second mixture; from about 20% to about 100% of the second mixture is heated until an exotherm is noted; then while maintaining reaction temperature, first adding the balance, if any, of the second mixture over about 0.25 hour to about 5 hours followed by addition over 0.25 to about 5 hours of the remaining first mixture, optionally adding additional initiator, whereupon the reaction is continued to completion.  
 
     
     
         20 . The lubricating oil composition of  claim 19  wherein the alkyl moieties of the ester groups of alkyl methacrylate monomer (b) have 2-(C 1-4  alkyl) substituents.  
     
     
         21 . The lubricating oil composition of  claim 19  wherein (c) comprises at least one nitrogen containing vinyl monomer.  
     
     
         22 . The lubricating oil composition of  claim 1  wherein the oil of lubricating viscosity comprises at least one mineral oil.  
     
     
         23 . The lubricating composition of  claim 1  wherein the oil of lubricating viscosity comprises at least one member selected from the group consisting of mineral oil and synthetic oil having kinematic viscosity at 100° C. ranging from about 4 to about 10 centistokes.  
     
     
         24 . The lubricating oil composition of  claim 22  wherein the mineral oil is a Group III oil.  
     
     
         25 . The lubricating oil composition of  claim 1  further comprising at least one member of the group consisting of pour point depressants, corrosion inhibitors, extreme pressure additives, antiwear additives, antioxidants, detergents, ashless dispersants, friction modifiers, and antifoam agents.  
     
     
         26 . An automatic transmission fluid comprising a major amount of an oil of lubricating viscosity, a total of from about 3% to about 10% by weight of a polymeric composition comprising 
 (A) from about 1% to about 99% by weight of at least one ethylene-aliphatic olefin copolymer wherein the aliphatic olefins contain from 3 to about 24 carbon atoms, said copolymer (A) having number average molecular weight ranging from about 600 to about 5000, and    (B) from about 99% to about 1% by weight of at least one copolymer comprising units derived from alkyl acrylate ester monomers containing from 2 to about 25 carbon atoms in the ester group, and optionally, from about 0.1% to about 20% by weight of at least one member of the group consisting of vinyl aromatic monomers and nitrogen-containing vinyl monomers. said copolymer (B) having number average molecular weight ranging from about 10,000 to about 350,000.    and minor amounts of at least one metal dithiophosphate, seal swell agent, pour point depressant, ashless dispersant and corrosion inhibitor.    
     
     
         27 . A gear oil composition comprising a major amount of a Group III oil, a total of from about 3% to about 30% by weight of a polymeric composition comprising 
 (A) from about 1% to about 99% by weight of at least one ethylene-aliphatic olefin copolymer wherein the aliphatic olefins contain from 3 to about 24 carbon atoms, said copolymer (A) having number average molecular weight ranging from about 600 to about 5000, and    (B) from about 99% to about 1% by weight of at least one copolymer comprising units derived from alkyl acrylate ester monomers containing from 2 to about 25 carbon atoms in the ester group, and optionally, from about 0.1% to about 20% by weight of at least one member of the group consisting of vinyl aromatic monomers and nitrogen-containing vinyl monomers. said copolymer (B) having number average molecular weight ranging from about 10,000 to about 350,000,    and minor amounts of extreme pressure additives, antiwear agents and corrosion inhibitors.    
     
     
         28 . A polymeric composition comprising a mixture of 
 (A) from about 1% to about 99% by weight of at least one ethylene-aliphatic olefin copolymer wherein the aliphatic olefins contain from 3 to about 24 carbon atoms, said copolymer (A) having number average molecular weight ranging from about 600 to about 5000, and    (B) from about 99% to about 1% by weight of at least one copolymer comprising units derived from alkyl acrylate ester monomers containing from 2 to about 25 carbon atoms in the ester group, and optionally, from about 0.1% to about 20% by weight of at least one member of the group consisting of vinyl aromatic monomers and nitrogen-containing vinyl monomers. said copolymer (B) having number average molecular weight ranging from about 10,000 to about 350,000.    
     
     
         29 . The polymeric composition of  claim 28  wherein copolymer (A) comprises an ethylene-alpha olefin copolymer wherein the ethylene content ranges from about 30 mole % to about 85 mole %.  
     
     
         30 . The polymeric composition of  claim 29  wherein (A) is an ethylene-propylene copolymer wherein the ethylene content ranges from about 40 mole % to about 85 mole %.  
     
     
         31 . The polymeric composition of  claim 29  wherein copolymer (B) comprises units derived from 
 (a) about 35 mole % to about 95 mole % of alkyl methacrylate ester monomers containing from about 9 to about 25 carbon atoms in the ester group and  
 (b) about 65 mole % to about 5 mole % of alkyl methacrylate ester monomers containing from about 7 to about 12 carbon atoms in the ester group, and optionally  
 (c) from about 0.1 mole % to about 20 mole % of at least one member of the group consisting of alkyl methacrylate ester monomers containing from 2 to about 8 carbon atoms in the ester group, which esters are different from methacrylate esters (a) and (b), vinyl aromatic monomers and nitrogen-containing vinyl monomers, with the proviso that no more than 60% by weight of the esters contain not more than 11 carbon atoms in the ester group.  
 
     
     
         32 . The polymeric composition of  claim 30  wherein the alkyl moieties of the ester groups of alkyl methacrylate monomer (b) have 2-(C 1-4  alkyl) substituents.  
     
     
         33 . The polymeric composition of  claim 28  wherein copolymer (B) comprises units derived from 
 (a) about 35 mole % to about 95 mole % of alkyl methacrylate ester monomers containing from about 13 to about 25 carbon atoms in the ester group and  
 (b) about 65 mole % to about 5 mole % of alkyl methacrylate ester monomers containing from about 7 to about 12 carbon atoms in the ester group.  
 
     
     
         34 . The polymeric composition of  claim 33  wherein the alkyl moieties of the ester groups of alkyl methacrylate monomer (b) have 2-(C 1-4  alkyl) substituents.  
     
     
         35 . The polymeric composition of  claim 30  wherein monomer (b) comprises 2-ethylhexyl methacrylate.  
     
     
         36 . The polymeric composition of  claim 32  comprising 
 from about 25% to about 75% by weight of (A) an ethylene-alpha olefin copolymer wherein the ethylene content ranges from about 30 mole % to about 85 mole %; and from about 75% to about 25% by weight of (B) a polymethacrylate copolymer comprising units derived from 
 (a) about 35 mole % to about 95 mole % of alkyl methacrylate ester monomers  
  containing from about 9 to about 25 carbon atoms in the ester group and  
 (b) about 65 mole % to about 5 mole % of alkyl methacrylate ester monomers containing from about 7 to about 12 carbon atoms in the ester group, and optionally  
 (c) from about 0.2 mole % to about 10 mole % of at least one member of the group consisting of alkyl methacrylate ester monomers containing from 2 to about 8 carbon atoms in the ester group, which esters are different from methacrylate esters (a) and (b), vinyl aromatic monomers and nitrogen-containing vinyl monomers, with the proviso that no more than 60% by weight of the esters contain not more than 11 carbon atoms in the ester group.  
 
 
     
     
         37 . The lubricating oil composition of  claim 36  wherein the alkyl moieties of the ester groups of alkyl methacrylate monomer (b) have 2-(C 1-4  alkyl) substituents.  
     
     
         38 . The polymeric composition of  claim 36  wherein (B) further comprises units derived from about 0.1% to about 10% by weight of at least one nitrogen containing monomer.  
     
     
         39 . The polymeric composition of  claim 36  wherein (B) is a copolymer prepared by a process comprising reacting, in the presence of a free radical initiator 
 (a) the methacrylic acid esters containing from about 9 to about 25 carbon atoms in the ester group, and  
 (b) the methacrylic acid esters containing from 7 to about 12 carbon atoms in the ester group, and  
 (c) the at least one monomer selected from the group consisting of methacrylic acid esters containing from 2 to about 8 carbon atoms in the ester group and which are different from methacrylic acid esters (a) and (b), vinyl aromatic monomers and nitrogen-containing vinyl monomers, with the proviso that no more than 60% by weight of the esters contain not more than 11 carbon atoms in the ester group, optionally in the presence of a chain transfer agent, wherein monomers (a) and (b), the free radical initiator, and if used, the chain transfer agent, are combined to prepare a first mixture; from about 10% to about 80% by weight of the first mixture of monomers (a) and (b) is combined with monomer (c) to prepare a second mixture; from about 20% to about 100% of the second mixture is heated until an exotherm is noted; then while maintaining reaction temperature, first adding the balance, if any, of the second mixture over about 0.25 hour to about 5 hours followed by addition over 0.25 to about 5 hours of the remaining first mixture, optionally adding additional initiator, whereupon the reaction is continued to completion.  
 
     
     
         40 . The polymeric composition of  claim 39  wherein the alkyl moieties of the ester groups of alkyl methacrylate monomer (b) have 2-(C 1-4  alkyl) substituents.  
     
     
         41 . A polymeric composition prepared by mixing together 
 (A) from about 1% to about 99% by weight of at least one ethylene-aliphatic olefin copolymer wherein the aliphatic olefins contain from 3 to about 24 carbon atoms, said copolymer having number average molecular weight ranging from about 600 to about 5000, and    (B) from about 99% to about 1% by weight of at least one copolymer comprising units derived from alkyl acrylate ester monomers containing from 2 to about 25 carbon atoms in the ester group, and optionally, from about 0.1% to about 20% by weight of at least one nitrogen containing monomer. said copolymer (B) having number average molecular weight ranging from about 10,000 to about 350,000.