Lubricant Compositions

Abstract

A lubricant composition characterized by the Society of Automotive Engineers (“SAE”) as 75W-140 capable of meeting the American Petroleum Institute's (“API”) GL-5 performance classification requirements for use in association with a device involving metal to metal contact of moving parts comprising: (a) base-stock comprising (i) at least one relatively low viscosity polyalphaolefin, and (ii) at least one diester; (b) viscosity improver comprising (i) at least one relatively high viscosity polyalphaolefin, and (ii) polyisobutylene; and (c) a performance additive comprising at least one additive effective to improve at least one property of the lubricant and/or the performance of the equipment in which the lubricant is to be used.

1 . A lubricant composition for use in association with a device involving metal to metal contact of moving parts comprising:
 (a) base-stock comprising (i) at least one relatively low viscosity polyalphaolefin, and (ii) at least one diester;   (b) viscosity improver comprising (i) at least one relatively high viscosity polyalphaolefin, and (ii) polyisobutylene; and   (c) a performance additive comprising at least one additive effective to improve at least one property of the lubricant and/or the performance of the equipment in which the lubricant is to be used;   
       wherein said lubricant composition meets the American Petroleum Institute's GL-5 performance classification requirements. 
     
     
         2 . The lubricant composition of  claim 1  wherein said lubricant composition is a multiviscosity-grade lubricant having a viscosity of about 150,000 cP at −40° C. and a kinematic viscosity at 100° C. of at least about 24.0 cSt and less than about 32.5 cSt. 
     
     
         3 . The lubricant composition of  claim 2  wherein said base-stock comprises at least one polyalphaolefin having a viscosity of not greater than about 12 centistokes (cSt). 
     
     
         4 . The lubricant composition of  claim 2  wherein said viscosity improver comprises a polyalphaolefin having a viscosity of greater than about 40 centistokes (cSt). 
     
     
         5 . The lubricant composition of  claim 2  comprising:
 (a) about 15-65% by weight of base-stock; 
 (b) about 30-75% by weight of viscosity improver; and 
 (c) about 7-35% by weight of additive. 
 
     
     
         6 . A lubricant composition for use in association with a device involving metal to metal contact of moving parts comprising:
 (a) about 10-35% by weight of a low viscosity polyalphaolefin;   (b) about 30-75% by weight of a high viscosity polyalphaolefin;   (c) about 5-30% by weight of a diester;   (d) about 2-25% by weight of polyisobutylene;   (e) about 5-10% by weight of an additive package; and, optionally   (f) about 0.001-0.004% by weight of an antifoam agent;   
       wherein said lubricant composition meets the American Petroleum Institute's GL-5 performance classification requirements. 
     
     
         7 . The lubricant composition of  claim 8  wherein said lubricant composition is a multiviscosity-grade lubricant having a viscosity of about 150,000 cP at −40° C. and a kinematic viscosity at 100° C. of at least about 24.0 cSt and less than about 32.5 cSt. 
     
     
         8 . The lubricant composition of  claim 7  wherein said low viscosity polyalphaolefin has a viscosity of not greater than about 12 centistokes (cSt). 
     
     
         9 . The lubricant composition of  claim 7  wherein said high viscosity polyalphaolefin has a viscosity of greater than about 40 centistokes (cSt). 
     
     
         10 . The lubricant composition of  claim 7  wherein said lubricant composition comprises:
 (a) about 12-20% by weight of a low viscosity polyalphaolefin; 
 (b) about 40-60% by weight of a high viscosity polyalphaolefin; 
 (c) about 7.5-20% by weight of a diester; 
 (d) about 5-15% by weight of polyisobutylene; 
 (e) about 7.5-9% by weight of an additive package; and, optionally 
 (f) about 0.001-0.004% by weight of an antifoam agent.