Grease compositions having calcium sulfonate and polyurea thickeners

Abstract

This disclosure relates to grease compositions having at least one base oil, and at least one thickener. The at least one thickener includes a combination of calcium sulfonate and a polyurea. The grease compositions have a service life or time at which 50 percent of the bearings fail (L50) of at least 100 hours at a temperature of 160° C., in accordance with DIN 51821 (FAG FE9). The calcium sulfonate includes from 60 weight percent to 95 weight percent, based on the total weight of the thickener, and the polyurea comprises from 5 weight percent to 40 weight percent, based on the total weight of the thickener. This disclosure also relates to a method of preparing the grease compositions. This disclosure further relates to a method for improving high temperature performance of a grease composition in a mechanical component lubricated with the grease composition.

1 . A grease composition comprising: at least one base oil; and at least one thickener; wherein said at least one thickener comprises a combination of calcium sulfonate and a polyurea; and wherein, in accordance with DIN 51821 (FAG FE9), the service life or time at which 50 percent of the bearings fail (L50) is at least 100 hours at a temperature of 160° C. 
     
     
         2 . The grease composition of  claim 1  wherein, in accordance with DIN 51821 (FAG FE9), the service life or time at which 50 percent of the bearings fail (L50) is at least 110 hours at a temperature of 160° C. 
     
     
         3 . The grease composition of  claim 1  wherein, when said grease composition is used in high temperature conditions, high temperature performance in accordance with DIN 51821 (FAG FE9) is improved, as compared to high temperature performance in accordance with ASTM D2265. 
     
     
         4 . The grease composition of  claim 1  wherein structural stability and resistance to breaking down is improved when tested under high temperature conditions in accordance with DIN 51821 (FAG FE9), as compared to structural stability and resistance to breaking down when tested under high temperature conditions in accordance with ASTM D2265. 
     
     
         5 . The grease composition of  claim 1  wherein the polyurea comprises a diurea, triurea, tetraurea, or polyurea made with an isocyanate-terminated prepolymer. 
     
     
         6 . The grease composition of  claim 1  wherein the at least one base oil comprises a Group I, Group II, Group III, Group IV, Group V base oil, and combinations thereof. 
     
     
         7 . The grease composition of  claim 1  further comprising at least one performance additive selected from the group consisting of an anticorrosive agent or corrosion inhibitor, an extreme pressure additive, an antiwear agent, a pour point depressants, an antioxidant or oxidation inhibitor, a rust inhibitor, a metal deactivator, a dispersant, a demulsifier, a dye or colorant/chromophoric agent, a seal compatibility agent, a friction modifier, a viscosity modifier/improver, a viscosity index improver, and combinations thereof. 
     
     
         8 . The grease composition of  claim 1  wherein the calcium sulfonate comprises from 60 weight percent to 95 weight percent, based on the total weight of the thickener, and the polyurea comprises from 5 weight percent to 40 weight percent, based on the total weight of the thickener. 
     
     
         9 . The grease composition of  claim 1  wherein the at least one base oil is present in an amount of from 50 to 95 weight percent, based on the total weight of the grease composition. 
     
     
         10 . The grease composition of  claim 1  wherein the at least one thickener is present in an amount of from 0.5 to 40 weight percent, based on the total weight of the grease composition. 
     
     
         11 . The grease composition of  claim 7  wherein the one or more performance additives are present in an amount of from 0.1 to 10 weight percent, based on the total weight of the grease composition. 
     
     
         12 . A method of preparing a grease composition comprising mixing at least one base oil, and at least one thickener, wherein said at least one thickener comprises a combination of calcium sulfonate and a polyurea; and wherein, in accordance with DIN 51821 (FAG FE9), the grease composition service life or time at which 50 percent of the bearings fail (L50) is at least 100 hours at a temperature of 160° C. 
     
     
         13 . The method of  claim 12  wherein, in accordance with DIN 51821 (FAG FE9), the grease composition service life or time at which 50 percent of the bearings fail (L50) is at least 110 hours at a temperature of 160° C. 
     
     
         14 . The method of  claim 12  wherein, when said grease composition is used in high temperature conditions, high temperature performance in accordance with DIN 51821 (FAG FE9) is improved, as compared to high temperature performance in accordance with ASTM D2265. 
     
     
         15 . The method of  claim 12  wherein structural stability and resistance to breaking down of said grease composition is improved when tested under high temperature conditions in accordance with DIN 51821 (FAG FE9), as compared to structural stability and resistance to breaking down of said grease composition when tested under high temperature conditions in accordance with ASTM D2265. 
     
     
         16 . The method of  claim 12  wherein the polyurea comprises a diurea, triurea, tetraurea, or polyurea made with an isocyanate-terminated prepolymer. 
     
     
         17 . The method of  claim 12  wherein the at least one base oil comprises a Group I, Group II, Group III, Group IV, Group V base oil, and combinations thereof. 
     
     
         18 . The method of  claim 12  wherein the grease composition further comprises at least one performance additive selected from the group consisting of an anticorrosive agent or corrosion inhibitor, an extreme pressure additive, an antiwear agent, a pour point depressants, an antioxidant or oxidation inhibitor, a rust inhibitor, a metal deactivator, a dispersant, a demulsifier, a dye or colorant/chromophoric agent, a seal compatibility agent, a friction modifier, a viscosity modifier/improver, a viscosity index improver, and combinations thereof. 
     
     
         19 . The method of  claim 12  wherein the calcium sulfonate comprises from 60 weight percent to 95 weight percent, based on the total weight of the thickener, and the polyurea comprises from 5 weight percent to 40 weight percent, based on the total weight of the thickener. 
     
     
         20 . The method of  claim 12  wherein the at least one base oil is present in an amount of from 50 to 95 weight percent, based on the total weight of the grease composition. 
     
     
         21 . The method of  claim 12  wherein the at least one thickener is present in an amount of from 0.5 to 40 weight percent, based on the total weight of the grease composition. 
     
     
         22 . The method of  claim 18  wherein the one or more performance additives are present in an amount of from 0.1 to 10 weight percent, based on the total weight of the grease composition. 
     
     
         23 . A method for improving high temperature performance of a grease composition in a mechanical component lubricated with the grease composition, said method comprising using a grease composition comprising: at least one base oil; and at least one thickener; wherein said at least one thickener comprises a combination of calcium sulfonate and a polyurea; and wherein, in accordance with DIN 51821 (FAG FE9), the service life or time at which 50 percent of the bearings fail (L50) is at least 100 hours at a temperature of 160° C. 
     
     
         24 . The method of  claim 23  wherein, in accordance with DIN 51821 (FAG FE9), the grease composition service life or time at which 50 percent of the bearings fail (L50) is at least 110 hours at a temperature of 160° C. 
     
     
         25 . The method of  claim 23  wherein, when said grease composition is used in high temperature conditions, high temperature performance in accordance with DIN 51821 (FAG FE9) is improved, as compared to high temperature performance in accordance with ASTM D2265. 
     
     
         26 . The method of  claim 23  wherein structural stability and resistance to breaking down of said grease composition is improved when tested under high temperature conditions in accordance with DIN 51821 (FAG FE9), as compared to structural stability and resistance to breaking down of said grease composition when tested under high temperature conditions in accordance with ASTM D2265. 
     
     
         27 . The method of  claim 23  wherein the polyurea comprises a diurea, triurea, tetraurea, or polyurea made with an isocyanate-terminated prepolymer. 
     
     
         28 . The method of  claim 23  wherein the at least one base oil comprises a Group I, Group II, Group III, Group IV, Group V base oil, and combinations thereof. 
     
     
         29 . The method of  claim 23  wherein the grease composition further comprises at least one performance additive selected from the group consisting of an anticorrosive agent or corrosion inhibitor, an extreme pressure additive, an antiwear agent, a pour point depressants, an antioxidant or oxidation inhibitor, a rust inhibitor, a metal deactivator, a dispersant, a demulsifier, a dye or colorant/chromophoric agent, a seal compatibility agent, a friction modifier, a viscosity modifier/improver, a viscosity index improver, and combinations thereof. 
     
     
         30 . The method of  claim 23  wherein the calcium sulfonate comprises from 60 weight percent to 95 weight percent, based on the total weight of the thickener, and the polyurea comprises from 5 weight percent to 40 weight percent, based on the total weight of the thickener. 
     
     
         31 . The method of  claim 23  wherein the at least one base oil is present in an amount of from 50 to 95 weight percent, based on the total weight of the grease composition. 
     
     
         32 . The method of  claim 23  wherein the at least one thickener is present in an amount of from 0.5 to 40 weight percent, based on the total weight of the grease composition. 
     
     
         33 . The method of  claim 29  wherein the one or more performance additives are present in an amount of from 0.1 to 10 weight percent, based on the total weight of the grease composition.