Grease compositions having improved performance

Abstract

This disclosure relates to grease compositions having at least one base oil, at least one soap or non-soap thickener, and at least one elastomeric triblock copolymer of the general configuration A-B-A, in which A is a relatively hydrophobic polymer block and B is a relatively hydrophilic polymer block, and in which A forms less than 50% by weight of the total molecular weight of the elastomeric triblock copolymer. When the grease compositions are used under high shear conditions, structural stability and resistance to breaking down in accordance with ASTM D7342 is improved. When the grease compositions are used in low temperature conditions, low temperature starting and running torque in accordance with ASTM D1478 is improved.

1 . A grease composition comprising: at least one base oil; at least one non-soap thickener; and at least one elastomeric triblock copolymer of the general configuration A-B-A; wherein A is a relatively hydrophobic polymer block and B is a relatively hydrophilic polymer block; and wherein A forms less than 50% by weight of the total molecular weight of the elastomeric triblock copolymer. 
     
     
         2 . The grease composition of  claim 1  wherein the at least one non-soap thickener comprises a polyurea. 
     
     
         3 . The grease composition of  claim 2  wherein, when used under high shear conditions, structural stability and resistance to breaking down in accordance with ASTM D7342 is improved, as compared to structural stability and resistance to breaking down achieved using a grease composition containing other than said polyurea. 
     
     
         4 . The grease composition of  claim 2  wherein, when used in low temperature conditions, low temperature starting torque in accordance with ASTM D1478 is improved, as compared to low temperature starting torque in accordance with ASTM D1478 achieved using a grease composition containing other than said polyurea. 
     
     
         5 . The grease composition of  claim 1  wherein the at least one elastomeric triblock copolymer comprises block segments of styrene monomer units and rubber monomer and/or comonomer units. 
     
     
         6 . The grease composition of  claim 1  wherein the at least one elastomeric triblock copolymer comprises polystyrene end blocks and elastomeric midblocks. 
     
     
         7 . The grease composition of  claim 1  wherein the at least one elastomeric triblock copolymer comprises styrene-ethylenebutylene-styrene type (S-EB-S), styrene-butadiene-styrene (SBS), or styrene-isoprene-styrene (SIS). 
     
     
         8 . 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. 
     
     
         9 . 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. 
     
     
         10 . 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. 
     
     
         11 . The grease composition of  claim 1  wherein the at least one non-soap thickener is present in an amount of from 0.5 to 20 weight percent, based on the total weight of the grease composition. 
     
     
         12 . The grease composition of  claim 1  wherein the at least one elastomeric triblock copolymer is present in an amount of from 0.5 to 2.5 weight percent, based on the total weight of the grease composition. 
     
     
         13 . The grease composition of  claim 9  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. 
     
     
         14 . A grease composition comprising: at least one base oil; at least one soap thickener; and at least one elastomeric triblock copolymer of the general configuration A-B-A; wherein A is a relatively hydrophobic polymer block and B is a relatively hydrophilic polymer block; and wherein A forms less than 50% by weight of the total molecular weight of the elastomeric triblock copolymer. 
     
     
         15 . The grease composition of  claim 14  wherein the at least one soap thickener comprises a lithium soap or lithium salt/soap complex. 
     
     
         16 . The grease composition of  claim 15  wherein, when used in low temperature conditions, low temperature starting and running torque in accordance with ASTM D1478 are improved, as compared to low temperature starting and running torque in accordance with ASTM D1478 achieved using a grease composition containing other than said lithium soap or lithium salt/soap complex. 
     
     
         17 . The grease composition of  claim 14  wherein the at least one elastomeric triblock copolymer comprises block segments of styrene monomer units and rubber monomer and/or comonomer units. 
     
     
         18 . The grease composition of  claim 14  wherein the at least one elastomeric triblock copolymer comprises polystyrene end blocks and elastomeric midblocks. 
     
     
         19 . The grease composition of  claim 14  wherein the at least one elastomeric triblock copolymer comprises styrene-ethylenebutylene-styrene type (S-EB-S), styrene-butadiene-styrene (SBS), or styrene-isoprene-styrene (SIS). 
     
     
         20 . The grease composition of  claim 14  wherein the at least one base oil comprises a Group I, Group II, Group III, Group IV, Group V base oil, and combinations thereof. 
     
     
         21 . The grease composition of  claim 14  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. 
     
     
         22 . The grease composition of  claim 14  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. 
     
     
         23 . The grease composition of  claim 14  wherein the at least one soap thickener is present in an amount of from 0.5 to 20 weight percent, based on the total weight of the grease composition. 
     
     
         24 . The grease composition of  claim 14  wherein the at least one elastomeric triblock copolymer is present in an amount of from 0.5 to 2.5 weight percent, based on the total weight of the grease composition. 
     
     
         25 . The grease composition of  claim 21  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. 
     
     
         26 . A method of preparing a grease composition comprising mixing at least one base oil, at least one non-soap thickener, and at least one elastomeric triblock copolymer of the general configuration A-B-A; wherein A is a relatively hydrophobic polymer block and B is a relatively hydrophilic polymer block; and wherein A forms less than 50% by weight of the total molecular weight of the elastomeric triblock copolymer. 
     
     
         27 . The method of  claim 26  wherein the at least one non-soap thickener comprises a polyurea. 
     
     
         28 . The method of  claim 27  wherein, when used under high shear conditions, structural stability and resistance to breaking down in accordance with ASTM D7342 is improved, as compared to structural stability and resistance to breaking down achieved using a grease composition containing other than said polyurea. 
     
     
         29 . The method of  claim 27  wherein, when used in low temperature conditions, low temperature starting torque in accordance with ASTM D1478 is improved, as compared to low temperature starting torque in accordance with ASTM D1478 achieved using a grease composition containing other than said polyurea. 
     
     
         30 . The method of  claim 26  wherein the at least one elastomeric triblock copolymer comprises block segments of styrene monomer units and rubber monomer and/or comonomer units. 
     
     
         31 . The method of  claim 26  wherein the at least one elastomeric triblock copolymer comprises polystyrene end blocks and elastomeric midblocks. 
     
     
         32 . The method of  claim 26  wherein the at least one elastomeric triblock copolymer comprises styrene-ethylenebutylene-styrene type (S-EB-S), styrene-butadiene-styrene (SBS), or styrene-isoprene-styrene (SIS). 
     
     
         33 . The method of  claim 26  wherein the at least one base oil comprises a Group I, Group II, Group III, Group IV, Group V base oil, and combinations thereof. 
     
     
         34 . The method of  claim 26  further comprising mixing 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. 
     
     
         35 . The method of  claim 26  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. 
     
     
         36 . The method of  claim 26  wherein the at least one non-soap thickener is present in an amount of from 0.5 to 20 weight percent, based on the total weight of the grease composition. 
     
     
         37 . The method of  claim 26  wherein the at least one elastomeric triblock copolymer is present in an amount of from 0.5 to 2.5 weight percent, based on the total weight of the grease composition. 
     
     
         38 . The method of  claim 34  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. 
     
     
         39 . A method of preparing a grease composition comprising mixing at least one base oil, at least one soap thickener, and at least one elastomeric triblock copolymer of the general configuration A-B-A; wherein A is a relatively hydrophobic polymer block and B is a relatively hydrophilic polymer block; and wherein A forms less than 50% by weight of the total molecular weight of the elastomeric triblock copolymer. 
     
     
         40 . The method of  claim 39  wherein the at least one soap thickener comprises a lithium soap or lithium salt/soap complex. 
     
     
         41 . The method of  claim 40  wherein, when used in low temperature conditions, low temperature starting and running torque in accordance with ASTM D1478 are improved, as compared to low temperature starting and running torque in accordance with ASTM D1478 achieved using a grease composition containing other than said lithium soap or lithium salt/soap complex. 
     
     
         42 . The method of  claim 39  wherein the at least one elastomeric triblock copolymer comprises block segments of styrene monomer units and rubber monomer and/or comonomer units. 
     
     
         43 . The method of  claim 39  wherein the at least one elastomeric triblock copolymer comprises polystyrene end blocks and elastomeric midblocks. 
     
     
         44 . The method of  claim 39  wherein the at least one elastomeric triblock copolymer comprises styrene-ethylenebutylene-styrene type (S-EB-S), styrene-butadiene-styrene (SBS), or styrene-isoprene-styrene (SIS). 
     
     
         45 . The method of  claim 39  wherein the at least one base oil comprises a Group I, Group II, Group III, Group IV, Group V base oil, and combinations thereof. 
     
     
         46 . The method of  claim 39  further comprising mixing 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. 
     
     
         47 . The method of  claim 39  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. 
     
     
         48 . The method of  claim 39  wherein the at least one soap thickener is present in an amount of from 0.5 to 20 weight percent, based on the total weight of the grease composition. 
     
     
         49 . The method of  claim 39  wherein the at least one elastomeric triblock copolymer is present in an amount of from 0.5 to 2.5 weight percent, based on the total weight of the grease composition. 
     
     
         50 . The method of  claim 46  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.