Viscosity modifiers for lubricant compositions

Abstract

A lubricant composition method of using the lubricant composition. The lubricant composition contains a base oil of lubricating viscosity and from about 5 to about 30 percent by weight of an additive comprising a shear stable olefin copolymer derived from a copolymer having a number average molecular weight ranging from about 50,000 to about 250,000. The shear stable olefin copolymer has a shear stability index of less than about 40, a polydispersity of not more than about 1.5, and a thickening efficiency of greater than about 1.8, and provides viscosity index improving properties to the lubricant composition.

1 . A lubricated surface comprising a thin film coating of a lubricant composition containing a base oil of lubricating viscosity and from about 5 to about 30 percent by weight of an additive comprising a shear stable olefin copolymer derived from a copolymer having a number average molecular weight ranging from about 50,000 to about 250,000, wherein the shear stable olefin copolymer has a shear stability index of less than about 40, a polydispersity of not more than about 1.5, and a thickening efficiency of greater than about 1.8, and wherein the amount of additive in the lubricant composition is based on a total weight of the lubricant composition.  
     
     
         2 . The lubricated surface of  claim 1 , wherein the lubricated surface comprises an engine drive train.  
     
     
         3 . The lubricated surface of  claim 1 , wherein the lubricated surface comprises an internal surface or component of an internal combustion engine.  
     
     
         4 . The lubricated surface of  claim 1 , wherein the lubricated surface comprises an internal surface or component of a compression ignition engine.  
     
     
         5 . The lubricated surface of  claim 1 , wherein the shear stable copolymer is derived from the group consisting of ethylene-propylene monomers, ethylene-propylene-diene monomers, styrene-isoprene, and styrene-neoprene monomers.  
     
     
         6 . The lubricated surface of  claim 1 , wherein the shear stable copolymer is derived from a relatively low temperature, homogenized copolymer.  
     
     
         7 . The lubricated surface of  claim 1 , wherein each monomeric unit of the shear stable copolymer contains from about 2 to about 10 carbon atoms.  
     
     
         8 . The lubricated surface of  claim 1 , wherein the shear stable copolymer comprises an amorphous ethylene containing copolymer having an ethylene content below about 70 percent by weight of the copolymer.  
     
     
         9 . A motor vehicle comprising the lubricated surface of  claim 1 .  
     
     
         10 . A vehicle having moving parts and containing a lubricant for lubricating the moving parts, the lubricant comprising an oil of lubricating viscosity and from about 5 to about 30 percent by weight of an additive comprising a shear stable olefin copolymer derived from a copolymer having a number average molecular weight ranging from about 50,000 to about 250,000, wherein the shear stable olefin copolymer has a shear stability index of less than about 40, a polydispersity of not more than about 1.5, and a thickening efficiency of greater than about 1.8, and wherein the amount of additive in the lubricant is based on a total weight of the lubricant.  
     
     
         11 . The vehicle of  claim 10 , wherein the shear stable copolymer is derived from the group consisting of ethylene-propylene monomers, ethylene-propylene-diene monomers, styrene-isoprene, and styrene-neoprene monomers.  
     
     
         12 . The vehicle of  claim 10 , wherein the shear stable copolymer comprises an olefin copolymer mechanically sheared in a homogenizer.  
     
     
         13 . The vehicle of  claim 10 , wherein the moving parts comprise a heavy duty diesel engine including exhaust gas recirculation and a lubricating system for the engine.  
     
     
         14 . The vehicle of  claim 10 , wherein each monomeric unit of the shear stable copolymer contains from about 2 to about 10 carbon atoms.  
     
     
         15 . The vehicle of  claim 10 , wherein the shear stable copolymer comprises an amorphous ethylene containing copolymer having an ethylene content below about 70 percent by weight of the copolymer.  
     
     
         16 . A fully formulated lubricant composition comprising a base oil component of lubricating viscosity and from about 5 to about 30 percent by weight of an additive comprising a shear stable olefin copolymer derived from a copolymer having a number average molecular weight ranging from about 50,000 to about 250,000, wherein the shear stable olefin copolymer has a shear stability index of less than about 40, a polydispersity of not more than about 1.5, and a thickening efficiency of greater than about 1.8, and wherein the amount of additive in the lubricant composition is based on a total amount of lubricant composition.  
     
     
         17 . The lubricant composition of  claim 16 , wherein the shear stable copolymer is derived from the group consisting of ethylene-propylene monomers, ethylene-propylene-diene monomers, styrene-isoprene, and styrene-neoprene monomers.  
     
     
         18 . The lubricant composition of  claim 16 , wherein the shear stable copolymer comprises an olefin copolymer mechanically sheared in a homogenizer.  
     
     
         19 . The lubricant composition of  claim 16 , wherein each monomeric unit of the shear stable copolymer contains from about 2 to about 10 carbon atoms.  
     
     
         20 . The lubricant composition of  claim 16 , wherein the shear stable copolymer comprises an amorphous ethylene containing copolymer having an ethylene content below about 70 percent by weight.  
     
     
         21 . A method for improving the viscosity index of a lubricant composition comprising mixing with the lubricant composition from about 5 to about 30 percent by weight of an additive comprising a shear stable olefin copolymer derived from a copolymer having a number average molecular weight ranging from about 50,000 to about 250,000, wherein the shear stable olefin copolymer has a shear stability index of less than about 40, a polydispersity of not more than about 1.5, and a thickening efficiency of greater than about 1.8, and wherein the amount of shear stable olefin copolymer in the lubricant composition is based on a total weight of the lubricant composition.  
     
     
         22 . The method of  claim 21 , wherein the lubricant composition comprises a multi-viscosity lubricating oil.  
     
     
         23 . The method of  claim 21 , wherein the wherein the shear stable copolymer is derived from the group consisting of ethylene-propylene monomers, ethylene-propylene-diene monomers, styrene-isoprene, and styrene-neoprene monomers.  
     
     
         24 . The method of  claim 21 , wherein the shear stable copolymer comprises an olefin copolymer mechanically sheared in a homogenizer.  
     
     
         25 . The method of  claim 21 , wherein each monomeric unit of the shear stable copolymer contains from about 2 to about 10 carbon atoms.  
     
     
         26 . The method of  claim 21 , wherein the shear stable copolymer comprises an amorphous ethylene containing copolymer having an ethylene content below about 70 percent by weight of the copolymer.  
     
     
         27 . A lubricant additive concentrate comprising a diluent or carrier oil and from about 5 to about 90 percent by weight of an additive comprising a shear stable olefin copolymer derived from a copolymer having a number average molecular weight ranging from about 50,000 to about 250,000, wherein the shear stable olefin copolymer has a shear stability index of less than about 40, a polydispersity of not more than about 1.5, and a thickening efficiency of greater than about 1.8, and wherein the amount of shear stable olefin copolymer in the lubricant composition is based on a total weight of the additive concentrate.  
     
     
         28 . The additive concentrate of  claim 27 , wherein the wherein the shear stable copolymer is derived from the group consisting of ethylene-propylene monomers, ethylene-propylene-diene monomers, styrene-isoprene, and styrene-neoprene monomers.  
     
     
         29 . The additive concentrate of  claim 27 , wherein the shear stable copolymer comprises an olefin copolymer mechanically sheared in a homogenizer.  
     
     
         30 . The additive concentrate of  claim 27 , wherein each monomeric unit of the shear stable copolymer contains from about 2 to about 10 carbon atoms.  
     
     
         31 . The additive concentrate of  claim 27 , wherein the shear stable copolymer comprises an amorphous ethylene containing copolymer having an ethylene content below about 70 percent by weight of the copolymer.  
     
     
         32 . A lubricant composition comprising a base oil and the additive concentrate of  claim 27 .  
     
     
         33 . A method of lubricating moving parts of a vehicle, the method comprising using as a lubricating oil for one or more moving parts of the vehicle a lubricant composition containing a base oil and a lubricant additive, the lubricant additive comprising a diluent or carrier oil and an amount of shear stable olefin copolymer derived from a copolymer having a number average molecular weight ranging from about 50,000 to about 250,000 sufficient to provide from about 5 to about 30 weight percent of the shear stable olefin copolymer in the lubricant composition, wherein the shear stable olefin copolymer has a shear stability index of less than about 40, a polydispersity of not more than about 1.5, and a thickening efficiency of greater than about 1.8, and wherein the amount of shear stable olefin copolymer in the lubricant composition is based on a total weight of the lubricant composition.  
     
     
         34 . The method of  claim 33 , wherein the wherein the shear stable copolymer is derived from the group consisting of ethylene-propylene monomers, ethylene-propylene-diene monomers, styrene-isoprene, and styrene-neoprene monomers.  
     
     
         35 . The method of  claim 33 , wherein the shear stable copolymer comprises an olefin copolymer mechanically sheared in a homogenizer.  
     
     
         36 . The method of  claim 33 , wherein each monomeric unit of the shear stable copolymer contains from about 2 to about 10 carbon atoms.  
     
     
         37 . The method of  claim 33 , wherein the shear stable copolymer comprises an amorphous ethylene containing copolymer having an ethylene content below about 70 percent by weight of the copolymer.  
     
     
         38 . The method of  claim 33  wherein the vehicle includes a diesel engine and wherein the moving parts include moving parts of the engine.  
     
     
         39 . The method of  claim 33  wherein the vehicle includes a marine vehicle having an engine, and wherein the moving parts include moving parts of the engine.  
     
     
         40 . The method of  claim 33 , wherein the vehicle includes a spark ignition engine, and wherein the moving parts include moving parts of the engine.  
     
     
         41 . The method of  claim 33 , wherein the vehicle includes a drive train, and wherein the moving parts include moving parts of the drive train.  
     
     
         42 . The method of  claim 33  wherein the vehicle includes an internal combustion engine having a crankcase and wherein the lubricant composition comprises a crankcase oil present in the crankcase of the vehicle.  
     
     
         43 . The method of  claim 33  wherein the lubricant composition comprises a drive train lubricant present in an automotive drive train of the vehicle.  
     
     
         44 . A method of lubricating moving parts comprising contacting the moving parts with a lubricant composition containing a lubricant additive, the lubricant additive comprising a diluent or carrier oil and from about 5 to about 95 percent by weight of a shear stable olefin copolymer derived from a copolymer having a number average molecular weight ranging from about 50,000 to about 250,000, wherein the shear stable olefin copolymer has a shear stability index of less than about 40, a polydispersity of not more than about 1.5, and a thickening efficiency of greater than about 1.8, wherein the lubricant composition contains from about 5 to about 30 percent by weight of the additive based on a total weight of the lubricant composition.  
     
     
         45 . The method of  claim 44  wherein the moving parts comprise moving parts of a vehicle.  
     
     
         46 . The method of  claim 44  wherein the vehicle includes a marine vehicle having an engine, and wherein the moving parts include moving parts of the engine.  
     
     
         47 . The method of  claim 44  wherein the moving parts include an internal combustion engine having a crankcase and wherein the lubricant composition comprises a crankcase oil present in the crankcase of the vehicle.  
     
     
         48 . The method of  claim 44  wherein the lubricant composition comprises a drive train lubricant present in an automotive drive train of the vehicle.