Lubrication greases including copolymers of tetrafluoroethyene oxide and hexafluoropropylene oxide

Abstract

A grease includes a perfluoropolyether oil copolymer and a thickener mixed with the copolymer. The copolymer includes about 20 mol % to about 80 mol % of —CF2CF2O— units, about 20 mol % to about 80 mol % of —CF(CF3)CF2O— units, and about 0 mol % to about 45 mol % of one or more additional perfluoroalkyleneoxy units. The copolymer has a viscosity index in the range of about 120 to about 220. The copolymer has an average TFEO run length of less than about 6. A process of forming a grease includes mixing a perfluoropolyether oil copolymer with a thickener to form the grease.

1 . A grease comprising:
 a perfluoropolyether oil copolymer comprising:
 about 20 mol % to about 80 mol % of —CF 2 CF 2 O— units; 
 about 20 mol % to about 80 mol % of —CF(CF 3 )CF 2 O— units; and 
 about 0 mol % to about 45 mol % of one or more additional perfluoroalkyleneoxy units; 
 said copolymer having a viscosity index in the range of about 120 to about 220; and 
 said copolymer having an average TFEO run length of less than about 6; and 
   a thickener mixed with the copolymer.   
     
     
         2 . The grease of  claim 1 , wherein the copolymer has a number average molecular weight in the range of about 1,500 to about 20,000 Da. 
     
     
         3 . The grease of  claim 2 , wherein the number average molecular weight is in the range about 3,500 to about 13,000 Da. 
     
     
         4 . The grease of  claim 1 , wherein the one or more additional perfluoroalkyleneoxy units comprises —CF 2 CF 2 CF 2 O— units. 
     
     
         5 . The grease of  claim 1 , wherein the ISO viscosity grade of the copolymer is above about 25. 
     
     
         6 . The grease of  claim 1 , wherein the viscosity index is in the range of about 150 to about 220. 
     
     
         7 . The grease of  claim 1 , wherein the average TFEO run length is less than about 4.5. 
     
     
         8 . The grease of  claim 1 , wherein the copolymer has a pour point of about −20° C. or less. 
     
     
         9 . The grease of  claim 8 , wherein the pour point is about −50° C. or less. 
     
     
         10 . The grease of  claim 1 , wherein the thickener is selected from the group consisting of polytetrafluoroethylene, talc, silica, fluorinated ethylene propylene, perfluoroalkoxy alkane, clay, graphite, surface-treated silica, boron nitride, calcium carbonate, and combinations thereof. 
     
     
         11 . The grease of  claim 1 , wherein the thickener is present in the grease in an amount in the range of about 1% to about 50% by weight of the grease. 
     
     
         12 . The grease of  claim 1 , wherein the thickener comprises particles having a surface area in the range of about 2 to about 35 m 2 /g. 
     
     
         13 . The grease of  claim 1 , wherein the thickener comprises particles having an average particle size in the range of 30 nm to 300 nm. 
     
     
         14 . The grease of  claim 1 , wherein the grease has a starting torque at −40° C. of less than 1100 g-cm. 
     
     
         15 . The grease of  claim 1 , wherein the grease has a running torque at −40° C. of less than 450 g-cm. 
     
     
         16 . A process of forming a grease, the process comprising:
 mixing a perfluoropolyether oil copolymer with a thickener to form the grease, wherein the perfluoropolyether oil copolymer comprises:
 about 20 mol % to about 80 mol % of —CF 2 CF 2 O— units; 
 about 20 mol % to about 80 mol % of —CF(CF 3 )CF 2 O— units; and 
 about 0 mol % to about 45 mol % of one or more additional perfluoroalkyleneoxy units; 
 said copolymer having a viscosity index in the range of about 120 to about 220; and 
 said copolymer having an average TFEO run length of less than about 6. 
   
     
     
         17 . The process of  claim 16 , wherein the mixing comprises milling the perfluoropolyether oil copolymer with the thickener. 
     
     
         18 . The process of  claim 16 , wherein the thickener is selected from the group consisting of polytetrafluoroethylene, talc, silica, fluorinated ethylene propylene, perfluoroalkoxy alkane, clay, graphite, surface-treated silica, boron nitride, calcium carbonate, and combinations thereof. 
     
     
         19 . The process of  claim 16 , wherein the grease has a starting torque at −40° C. of less than 1100 g-cm. 
     
     
         20 . The process of  claim 16 , wherein the grease has a running torque at −40° C. of less than 450 g-cm.