Lubricant composition containing Ethylene-Alpha Olefin Copolymer viscosity modifier

Abstract

Provided are lubricant compositions containing ethylene/α-olefin copolymer viscosity modifiers which impart unique viscometrics in high VI/low aromatics base stocks for engine oil applications. In one form, the lubricant compositions include a blend of Group I to Group V base stocks, or mixtures thereof, and an ethylene/α-olefin copolymer made from ethylene with one or more α-olefin, wherein the α-olefin has from 3 to 18 carbon atoms and the ethylene/α-olefin copolymer has a number average molecular weight between 800 and 20,000 and a molecular weight distribution of less than 3.0.

1 . A lubricant composition comprising a blend of Group I to Group V base stocks, or mixtures thereof, and an ethylene/α-olefin copolymer made from ethylene with one or more α-olefin, wherein the α-olefin has from 3 to 18 carbon atoms and the ethylene/α-olefin copolymer has a number average molecular weight between 800 and 20,000 and a molecular weight distribution of less than 3.0. 
     
     
         2 . The lubricant composition of  claim 1 , wherein the ethylene/α-olefin copolymer comprises between 10 wt % and 45 wt % ethylene content. 
     
     
         3 . The lubricant composition of  claim 1 , comprising between 1 wt % to 20 wt % of the ethylene/α-olefin copolymer. 
     
     
         4 . The lubricant composition of  claim 3 , comprising between 2 to 15% of the ethylene/α-olefin copolymer. 
     
     
         5 . The lubricant composition of  claim 1 , wherein the ethylene/α-olefin copolymer has a number average molecular weight ranging from 2000 to 10,000. 
     
     
         6 . The lubricant composition of  claim 5 , wherein the ethylene/α-olefin copolymer has a number average molecular weight ranging from 3000 to 8000. 
     
     
         7 . The lubricant composition of  claim 6 , wherein the ethylene/α-olefin copolymer has a number average molecular weight ranging from 3000 to 6000. 
     
     
         8 . The lubricant composition of  claim 1 , wherein the ethylene/α-olefin copolymer is made with metallocene catalysts. 
     
     
         9 . The lubricant composition of  claim 1 , wherein the base stock is a Group IV base stock. 
     
     
         10 . The lubricant composition of  claim 1 , wherein the base stock is a Group V base stock. 
     
     
         11 . The lubricant composition of  claim 1 , wherein the base stock is a mixture of a Group IV base stock and a Group V base stock. 
     
     
         12 . The lubricant composition of  claim 1 , wherein the ethylene/α-olefin copolymer is a liquid ethylene/1-butene copolymer. 
     
     
         13 . The lubricant composition of  claim 3 , wherein the ethylene/α-olefin copolymer is a liquid ethylene/1-butene copolymer. 
     
     
         14 . The lubricant composition of  claim 1 , wherein the ethylene/α-olefin copolymer has a molecular weight distribution of less than 2.5. 
     
     
         15 . The lubricant composition of  claim 14 , wherein the ethylene/α-olefin copolymer has a molecular weight distribution of less than 2.0. 
     
     
         16 . The lubricant composition of  claim 1 , wherein the composition has a high temperature shear viscosity (HTHS) according to ASTM D4683 of greater than 2.5858×Ln(100° C. Kv, in cS)−2.6738. 
     
     
         17 . The lubricant composition of  claim 1 , wherein the composition has a high temperature shear viscosity (HTHS) according to ASTM D4683 of at least 3.5 cP and a mini rotary viscosity (MRV) at −40° C. according to ASTM D4684 of less than 15,000 cP. 
     
     
         18 . The lubricant composition of  claim 1 , wherein the composition has a MRV viscosity at −40° C. according to ASTM D4684 of less than 1.838.8×e (0.5923×(HTHS vis in cP)) . 
     
     
         19 . The lubricant composition of  claim 1 , wherein the composition has a high temperature shear viscosity (HTHS) according to ASTM D4683 of at least 2.9 cP and a mini rotary viscosity (MRV) at −40° C. according to ASTM D4684 of less than 1.838.8×e (0.5923×(HTHS vis in cP)) . 
     
     
         20 . The lubricant composition of  claim 1 , wherein the composition has a high temperature shear viscosity (HTHS) according to ASTM D4683 of at least 2.9 cP and a mini rotary viscosity (MRV) at −40° C. according to ASTM D4684 of less than 26,000 cP. 
     
     
         21 . The lubricant composition of  claim 1 , wherein the composition has an HTHS of at least 2.6 cP and a kinematic viscosity at 100° C. of less than 16 cSt. 
     
     
         22 . The lubricant composition of  claim 21 , wherein the ethylene/α-olefin copolymer is a liquid ethylene/1-butene copolymer. 
     
     
         23 . The lubricant composition of  claim 22 , wherein the ethylene/1-butene copolymer comprises between 19 wt % and 45 wt % ethylene content. 
     
     
         24 . The lubricant composition of  claim 23 , wherein the ethylene/1-butene copolymer has a number average molecular weight between 2000 and 6,000 and a molecular weight distribution of less than 2.5. 
     
     
         25 . The lubricant composition of  claim 1 , further comprising lubricant additives selected from viscosity index improvers, corrosion inhibitors, dispersants, oxidation inhibitors, detergents, rust inhibitors, antiwear agents, anti-foaming agents, flow improvers, friction modifiers, seal swellants, and combinations thereof. 
     
     
         26 . The lubricant composition of  claim 12  including less than 30 wt % of the ethylene-1-butene copolymer. 
     
     
         27 . The lubricant composition of  claim 26  including between 1 wt % and 20 wt % of the ethylene-1-butene copolymer.