Novel formulation approach to extend the high temperature performance of lithium complex greases in rolling bearings

Abstract

The present disclosure provides a lithium complex grease with high-temperature resistivity and a method of making the same. The lithium complex grease includes: a lithium complex thickener, a friction modifier, a polymer or copolymer, and at least one synthetic base oil with alkylated naphthalene. The lithium complex grease can be substantially free of polytetrafluoroethylene. Furthermore, the lithium complex grease can have a median failure rate with via ball bearing test (e.g., using the FE9 grease life test method of DIN 51 821) performed at 160° C. of no less than 100 hours.

1 . A lithium complex grease with high-temperature resistivity, the lithium complex grease comprising:
 a lithium complex thickener;   a friction modifier;   a polymer or copolymer; and   at least one synthetic base oil having alkylated naphthalene.   
     
     
         2 . The lithium complex grease of  claim 1 , wherein the friction modifier is at least one of a molybdenum (Mo) friction modifier, molybdenum dithiocarbamate (MoDTC), molybdenum dithiophosphate (MoDTP), MOLYVAN® 822, MOLYVAN® 855, MOLYVAN® L, MOLYVAN® 807, MOLYVAN® A, MOLYVAN® 2000, ADEKA SAKURA LUBE 525, MOLYVAN® 3000, or a combination thereof. 
     
     
         3 . The lithium complex grease of  claim 1 , wherein the polymer or copolymer comprises at least one of ethylene, propylene, an ethylene-propylene co-polymer, or a combination thereof. 
     
     
         4 . The lithium complex grease of  claim 3 , wherein the polymer or copolymer is Vistamaxx™ 6202. 
     
     
         5 . The lithium complex grease of  claim 1 , wherein the at least one synthetic base oil includes at least one of an alkylated naphthalene base oil, a polyalphaolefin (PAO) base oil, alkylated naphthalene in PAO base oil, or a combination thereof. 
     
     
         6 . The lithium complex grease of  claim 5 , wherein the alkylated naphthalene base oil is at least one of Synesstic™ 5, Synesstic™ 12, or a combination thereof. 
     
     
         7 . The lithium complex grease of  claim 5 , wherein the PAO base oil is at least one of SpectraSyn™ 2, SpectraSyn™ 2B, SpectraSyn™ 2C, SpectraSyn™ 4, SpectraSyn™ 5, SpectraSyn™ 6, SpectraSyn™ 8, SpectraSyn™ 10, SpectraSyn™ 40, SpectraSyn™ 100, Syncon® Barrier Oil, or a combination thereof. 
     
     
         8 . The lithium complex grease of  claim 1 , wherein the lithium complex grease has at least one of the following:
 3% to 30% of the lithium complex thickener;   0.75% to 10% of the friction modifier;   0.25% to 7% of the polymer or copolymer;   10.0% to 40% of the alkylated naphthalene base oil;   13.0% to 76% of the PAO base oil; or   a combination thereof.   
     
     
         9 . The lithium complex grease of  claim 8 , wherein the lithium complex grease has at least one of the following:
 6% to 20% of the lithium complex thickener;   1.0% to 6% of the friction modifier;   0.5% to 4% of the polymer or copolymer;   10.0% to 40% of the alkylated naphthalene base oil;   30.0% to 82.5% of the PAO base oil; or   a combination thereof.   
     
     
         10 . The lithium complex grease of  claim 1 , wherein the lithium complex grease is substantially free of polytetrafluoroethylene (PTFE), polyester (POE) base oil, or substantially free of PTFE and POE base oil. 
     
     
         11 . The lithium complex grease of  claim 1 , further comprising at least one additive selected from the group consisting of an emulsifier, a co-thickener, a corrosion inhibitor, an antioxidant, a wear inhibitor, a tackiness agent, a colorant, an odor control agent, a filler, or a combination thereof. 
     
     
         12 . A method of preparing a lithium complex grease with high-temperature resistivity, the method comprising mixing a lithium complex thickener, a friction modifier, a polymer or copolymer, and at least one synthetic base oil with alkylated naphthalene. 
     
     
         13 . The method of  claim 12 , wherein the lithium complex grease has at least one of the following:
 3% to 30% of the lithium complex thickener;   0.75% to 10% of the friction modifier;   0.25% to 7% of the polymer or copolymer;   10.0% to 40% of the alkylated naphthalene base oil;   at least 13.0% to 76% of the PAO base oil; or   a combination thereof.   
     
     
         14 . The method of  claim 12 , wherein the lithium complex grease has at least one of the following:
 6% to 20% of the lithium complex thickener;   1.0% to 6% of the friction modifier;   0.5% to 4% of the polymer or copolymer;   10.0% to 40% of the alkylated naphthalene base oil;   30.0% to 82.5% of the PAO base oil; or   a combination thereof.   
     
     
         15 . The method of  claim 12 , wherein the lithium complex grease has a median failure rate with a ball bearing test performed at 160° C. of no less than 100 hours. 
     
     
         16 . The method of  claim 12 , wherein the lithium complex grease is substantially free of polytetrafluoroethylene (PTFE), polyester (POE) base oil, or substantially free of PTFE and POE base oil. 
     
     
         17 . The method of  claim 12 , wherein the lithium complex grease further comprises at least one additive selected from the group consisting of an emulsifier, a co-thickener, a corrosion inhibitor, an antioxidant, a wear inhibitor, a tackiness agent, a colorant, an odor control agent, a filler, or a combination thereof.