Lubricant formulations with enhanced anti-wear and extreme pressure performance

Abstract

A lubricant formulation contains: (a) greater than 50 weight-percent hydrocarbon base oil; (b) 5 weight-percent or more and less than 50 weight-percent of one or a combination of more than one oil soluble polyalkylene glycol selected from a group consisting of monol, diol and triol initiated 1,2-butylene oxide homopolymers and monol initiated copolymers of 1,2-butylene oxide and propylene oxide; (c) 0.1 weight-percent or more and 5 weight-percent or less of sulfurized olefin; and (d) 0.1 weight-percent or more and 2 weight-percent or less of phosphate ester; where weight-percent is relative to total lubricant formulation weight.

1 . A lubricant formulation comprising:
 a. greater than 50 weight-percent hydrocarbon base oil;   b. 5 weight-percent or more and less than 50 weight-percent of one or a combination of more than one oil soluble polyalkylene glycol selected from a group consisting of monol, diol and triol initiated 1,2-butylene oxide homopolymers and monol initiated copolymers of 1,2-butylene oxide and propylene oxide;   c. 0.1 weight-percent or more and 5 weight-percent or less of sulfurized olefin; and   d. 0.1 weight-percent or more and 2 weight-percent or less of phosphate ester;   
       wherein the weight-percent of components a.-d. is relative to total lubricant formulation weight. 
     
     
         2 . The lubricant formulation of  claim 1 , wherein the oil soluble polyalkylene glycol is selected from a group consisting of monol initiated 1,2-butylene oxide homopolymers, diol initiated 1,2-butylene oxide homopolymers and monol initiated random copolymers of 1,2-butylene oxide and propylene oxide. 
     
     
         3 . The lubricant of  claim 1 , wherein the oil soluble polyalkylene glycol is a dodecanol-initiated random copolymer of 1,2-butylene oxide and propylene oxide. 
     
     
         4 . The lubricant of  claim 1 , wherein the oil soluble polyalkylene glycol is a butanol initiated homopolymer of 1,2-butylene oxide. 
     
     
         5 . The lubricant of  claim 1 , wherein the oil soluble polyalkylene glycol is a diol initiated homopolymer of 1,2-butylene oxide 
     
     
         6 . The lubricant formulation of  claim 1 , wherein the hydrocarbon base oil is selected from Group II, III and Group IV base oils. 
     
     
         7 . The lubricant formulation of  claim 1 , wherein the sulfurized olefin is sulfurized isobutylene. 
     
     
         8 . The lubricant formulation of  claim 1 , wherein the concentration of oil soluble polyalkylene glycol is five weight-percent or more and 30 weight-percent or less with weight-percent based on total weight of the lubricant formulation. 
     
     
         9 . The lubricant formulation of  claim 1 , further characterized by being free of sulfurized fatty oil. 
     
     
         10 . The lubricant formulation of  claim 1 , further characterized by the formulation containing less than 75 weight-percent polyalphaolefin base oil based on total lubricant formulation weight. 
     
     
         11 . A method of increasing anti-wear performance without reducing extreme pressure performance of a lubricant formulation containing a hydrocarbon base oil, a sulfurized isobutylene extreme pressure additive and a phosphate ester anti-wear additive, the method comprising including an oil soluble polyalkylene glycol selected from a group consisting of monol, diol and triol initiated 1,2-butylene oxide homopolymers and monol initiated copolymers of 1,2-butylene oxide and propylene oxide into the lubricant formulation so as to obtain the lubricant formulation of  claim 1 . 
     
     
         12 . The method of  claim 11 , where the oil soluble polyalkylene glycol is selected from a group consisting of monol initiated 1,2-butylene oxide homopolymers, diol initiated 1,2-butylene oxide homopolymers and monol initiated random copolymers of 1,2-butylene oxide and propylene oxide.