Lubricants containing blends of polymers

Abstract

A lubricant composition comprising (a) an oil of lubricating viscosity; (b) a (meth)-acrylate-containing polymer comprising a multiplicity of arms containing at least 20 carbon atoms, said arms being attached to a multivalent organic moiety; and (c) an ethylene/olefin copolymer having a weight average molecular weight of about 10,000 to about 250,000, wherein the copolymer comprises about 40 to about 70 weight percent polymerized ethylene monomers and optionally further comprises polymerized propylene monomers; exhibits good viscometric and antiwear properties.

1 . A lubricant composition comprising:
 (a) an oil of lubricating viscosity;   (b) a (meth)acrylate-containing polymer comprising a multiplicity of arms wherein the arms contain at least about 20 carbon atoms, said arms being attached to a multivalent organic moiety; and   (c) an ethylene/olefin copolymer having a weight average molecular weight of about 5000 to about 250,000, wherein the copolymer comprises about 40 to about 70 weight percent polymerized ethylene monomer and further comprises one or more polymerized olefin monomers of 3 to 6 carbon atoms.   
     
     
         2 . (canceled) 
     
     
         3 . The lubricant composition of  claim 1  wherein said arms are polymeric entities comprising alkyl (meth)acrylate monomer units. 
     
     
         4 . The lubricant composition of  claim 1  wherein said arms are polymeric entities comprising comonomers of C10-C18 alkyl methacrylate groups and C1-C9 alkyl methacrylate groups. 
     
     
         5 . The lubricant composition of  claim 1  wherein the arms comprise random copolymers or block copolymers. 
     
     
         6 . (canceled) 
     
     
         7 . The lubricant composition of  claim 1  wherein the number of arms attached to the multivalent organic moiety is 3 to 20. 
     
     
         8 . The lubricant composition of  claim 1  wherein the number average molecular weight of the arms is about 10,000 to about 200,000. 
     
     
         9 . (canceled) 
     
     
         10 . The lubricant composition of  claim 1  wherein the (meth)-acrylate-containing polymer comprises a star polymer with multiple arms linked to a core. 
     
     
         11 . The lubricant composition of  claim 10  wherein the core comprises polymerized monomers of an alkylene glycol dimethacrylate. 
     
     
         12 . The lubricant composition of  claim 1  wherein said arms comprise hydrocarbyl groups. 
     
     
         13 . The lubricant composition of  claim 1  wherein the (meth)acrylate-containing polymer comprises a comb polymer. 
     
     
         14 . The lubricant composition of  claim 13  wherein said arms are polymeric entities comprising conjugated diene monomer units or hydrogenated conjugated diene monomer units or isobutylene monomer units. 
     
     
         15 . (canceled) 
     
     
         16 . The lubricant composition of  claim 1  wherein the amount of the (meth)acrylate-containing polymer comprising a multiplicity of arms is present in an amount of about 0.1 to 2.5 percent by weight. 
     
     
         17 . (canceled) 
     
     
         18 . The lubricant composition of  claim 1  wherein the ethylene/olefin copolymer comprises propylene monomer units. 
     
     
         19 . The lubricant composition of  claim 1  wherein the ethylene/olefin copolymer comprises about 40 to about 50 percent by weight ethylene monomer units and about 50 to about 60 percent by weight propylene monomer units. 
     
     
         20 . The lubricant composition of  claim 1  wherein the ethylene/olefin copolymer has a weight average molecular weight of about 20,000 to about 180,000. 
     
     
         21 . The lubricant composition of  claim 1  wherein the amount of the ethylene/olefin copolymer is about 0.1 to about 10 percent by weight. 
     
     
         22 . (canceled) 
     
     
         23 . (canceled) 
     
     
         24 . A lubricant composition of  claim 1  suitable for lubricating a motorcycle crankcase and wet clutch, further comprising an overbased calcium detergent in an amount of 0.2 to 1.8 weight percent of the composition, an ashless dispersant in an amount of 0.8 to 3.2 weight percent of the composition, and a friction modifying additive that increases static friction at a friction plate-steel plate interface in an amount of 0.05 to 1.85 weight percent of the composition. 
     
     
         25 . A method for lubricating a mechanical device comprising supplying thereto the lubricant composition of  claim 1 . 
     
     
         26 . The method of  claim 25  wherein the mechanical device comprises a hydraulic system. 
     
     
         27 . The method of  claim 25  wherein the mechanical device comprises an internal combustion engine. 
     
     
         28 . (canceled) 
     
     
         29 . (canceled) 
     
     
         30 . (canceled)