Lubricant Compositions With Improved Wear Control

Abstract

This disclosure provides a method for improving wear control, while maintaining or improving energy efficiency, in a mechanical component having sliding or rolling between contacting surfaces. The method involves using a lubricant composition in the mechanical component having sliding or rolling between contacting surfaces. The lubricant composition has a base stock blend as a major component, and at least one lubricant additive, as a minor component. The base stock blend has at least one first base stock having a viscosity from 1 to 50 cSt at 40° C. and at least one second base stock having viscosity from 100 to 2000 cSt at 40° C. The first base stock is present in an amount greater than 50 to 95 wt % of the base stock blend, and the second base stock is present in an amount from 5 to less than 50 wt % of the base stock blend. The second base stock is miscible with the first base stock.

1 . A method for improving wear control, while maintaining or improving energy efficiency, in a mechanical component having sliding or rolling between contacting surfaces, said method comprising using a lubricant composition in the mechanical component having sliding or rolling between contacting surfaces, the lubricant composition comprising a base stock blend as a major component, and at least one lubricant additive, as a minor component; wherein the base stock blend comprises at least one first base stock having a viscosity from 1 cSt to 50 cSt at 40° C. as determined by ASTM D-445, and at least one second base stock having viscosity from 100 cSt to 2000 cSt at 40° C. as determined by ASTM D-445; wherein the first base stock is present in an amount greater than 50 to 95 weight percent of the base stock blend, and the second base stock is present in an amount from 5 to less than 50 weight percent of the base stock blend; and wherein the second base stock is miscible with the first base stock. 
     
     
         2 . The method of  claim 1  wherein, in the mechanical component having sliding or rolling between contacting surfaces lubricated with the lubricant composition, traction coefficient (Tc) is controlled by concentration of the first base stock, and film thickness is controlled by the concentration of the second base stock. 
     
     
         3 . The method of  claim 1  wherein the first base stock is present in an amount from 60 to 95 weight percent of the base stock blend, and the second base stock is present in an amount from 5 to 40 weight percent of the base stock blend. 
     
     
         4 . The method of  claim 1  wherein the first base stock comprises a Group I, Group II, Group III, Group IV or Group V base oil, and the second base stock comprises a Group I, Group II, Group III, Group IV or Group V base oil. 
     
     
         5 . The method of  claim 1  wherein the first base stock comprises a polyalphaolefin (PAO) base oil, and the second base stock comprises a polyalphaolefin (PAO) base oil or a metallocene catalyzed polyalphaolefin (PAO) base oil. 
     
     
         6 . The method of  claim 1  wherein the base stock blend is present in an amount from 70 to 95 weight percent of the lubricant composition. 
     
     
         7 . The method of  claim 1  wherein the first base stock has a traction coefficient (Tc) of from 0.008 to 0.015 as determined by MTM TC Method, the second base stock has a traction coefficient (Tc) of from 0.008 to 0.025 as determined by MTM TC Method, and the lubricant composition has a traction coefficient (Tc) of less than 0.15 as determined by MTM TC Method. 
     
     
         8 . The method of  claim 1  wherein the lubricant composition further comprises one or more of a viscosity modifier, dispersant, detergent, antioxidant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor, and anti-rust additive. 
     
     
         9 . The method of  claim 1  wherein traction coefficient (Tc) is independent of viscosity of the lubricant composition. 
     
     
         10 . The method of  claim 1  wherein the base stock blend is a bimodal blend. 
     
     
         11 . The method of  claim 1  wherein, in the mechanical component having sliding or rolling between contacting surfaces lubricated with the lubricant composition, a phase separation or transition is induced in a mechanical contact zone. 
     
     
         12 . The method of  claim 1  wherein the lubricant composition is a finished gear, transmission, engine or industrial lubricant.