Inverse micellar compositions containing lubricant additives

Abstract

This disclosure relates to lubricating engines using formulated lubricating oils to reduce wear and improve engine fuel efficiency. The formulated lubricating oils contain a major amount of a nonpolar lubricating oil base stock and a minor amount of one or more polar lubricating oil additives. The one or more polar lubricating oil additives include swollen inverse micelles dispersed in the nonpolar lubricating oil base stock. The swollen inverse micelles include (i) a liquid polar core containing a polar solvent and one or more polar lubricating oil additives having solubility in the polar solvent, and (ii) a layer of liquid surfactant molecules enclosing the liquid polar core in which polar heads of the liquid surfactant molecules are oriented towards the liquid polar core. A method of improving solubility of polar lubricating oil additives in a nonpolar lubricating oil base stock is also provided.

What is claimed is: 
     
         1 . A lubricating oil comprising a nonpolar lubricating oil base stock as a major component and one or more polar lubricating oil additives as a minor component; wherein said one or more polar lubricating oil additives comprise swollen inverse micelles dispersed in said nonpolar lubricating oil base stock; and wherein said swollen inverse micelles comprise (i) a liquid polar core containing a polar solvent and one or more polar lubricating oil additives having solubility in said polar solvent, and (ii) a layer of liquid surfactant molecules enclosing said liquid polar core in which polar heads of the liquid surfactant molecules are oriented towards the liquid polar core. 
     
     
         2 . The lubricating oil of  claim 1  wherein the nonpolar lubricating oil base stock comprises a Group I, Group II, Group III, Group IV or Group V base oil. 
     
     
         3 . The lubricating oil of  claim 1  wherein the polar solvent is selected from the group consisting of glycols, alcohols, esters, ethers, carboxylic acids, amines, organic compounds containing one or more polar functional groups, and mixtures thereof. 
     
     
         4 . The lubricating oil of  claim 1  wherein the one or more polar lubricating oil additives are selected from the group consisting of friction modifiers, antioxidants, corrosion inhibitors, rust inhibitors, metal deactivators, anti-wear agents and/or extreme pressure additives, dispersants, detergents, anti-seizure agents, wax modifiers, viscosity index improvers, viscosity modifiers, fluid-loss additives, seal compatibility agents, lubricity agents, anti-staining agents, chromophoric agents, defoamants, demulsifiers, emulsifiers, densifiers, wetting agents, gelling agents, tackiness agents, colorants, antifoam agents, and pour point depressants. 
     
     
         5 . The lubricating oil of  claim 1  wherein the one or more polar lubricating oil additives comprise one or more friction modifiers, antioxidants, corrosion inhibitors, rust inhibitors, or mixtures thereof. 
     
     
         6 . The lubricating oil of  claim 1  wherein the surfactant comprises a succinimide, a succinate ester, a succinate ester amide, a hydrocarbyl-substituted succinic acid derivative, a hydrocarbyl-substituted succinic anhydride derivative, an alkenylsuccinic derivative, or mixtures thereof. 
     
     
         7 . The lubricating oil of  claim 1  wherein the surfactant comprises a succinate ester, a phenate, a sulfonate, a sulfurized phenate, a salicylate, a naphthenate, a stearate, a carbamate, a thiocarbamate, a phosphorus derivative, or mixtures thereof. 
     
     
         8 . The lubricating oil of  claim 1  wherein the surfactant comprises polyisobutylene succinimide polyamine (PIBSA-PAM). 
     
     
         9 . The lubricating oil of  claim 1  wherein the swollen inverse micelles have a diameter of between 0.01 μm and 1 μm. 
     
     
         10 . The lubricating oil of  claim 1  wherein the nonpolar lubricating oil base stock is present in an amount from 70 weight percent to 95 weight percent, and the one or more polar lubricating oil additives are present in an amount from 0.1 weight percent to 10 weight percent or greater, based on the total weight of the lubricating oil. 
     
     
         11 . The lubricating oil of  claim 1  wherein the solubility of the polar lubricating oil additives in the nonpolar lubricating oil base stock is improved as compared to solubility achieved using a lubricating oil containing polar lubricating oil additives in a nonpolar lubricating oil base stock and not containing said swollen inverse micelles. 
     
     
         12 . The lubricating oil of  claim 11  wherein the one or more polar lubricating oil additives comprise one or more inorganic friction modifiers, antioxidants, corrosion inhibitors, rust inhibitors, or mixtures thereof. 
     
     
         13 . The lubricating oil of  claim 1  wherein surface performance in an engine is improved as compared to surface performance in an engine using a lubricating oil containing polar lubricating oil additives in a nonpolar lubricating oil base stock and not containing said swollen inverse micelles. 
     
     
         14 . The lubricating oil of  claim 13  wherein surface performance comprises increasing thickness of a lubricating film at contacts requiring elastohydrodynamic lubrication (EHL) in said engine. 
     
     
         15 . The lubricating oil of  claim 1  which is used in automotive, marine, aviation, and industrial engine and machine component applications. 
     
     
         16 . A method of improving solubility of polar lubricating oil additives in a nonpolar lubricating oil base stock, said method comprising providing a lubricating oil comprising a nonpolar lubricating oil base stock as a major component and one or more polar lubricating oil additives as a minor component; wherein said one or more polar lubricating oil additives comprise swollen inverse micelles dispersed in said nonpolar lubricating oil base stock; and wherein said swollen inverse micelles comprise (i) a liquid polar core containing a polar solvent and one or more polar lubricating oil additives having solubility in said polar solvent, and (ii) a layer of liquid surfactant molecules enclosing said liquid polar core in which polar heads of the liquid surfactant molecules are oriented towards the liquid polar core. 
     
     
         17 . The method of  claim 16  wherein the nonpolar lubricating oil base stock comprises a Group I, Group II, Group III, Group IV or Group V base oil. 
     
     
         18 . The method of  claim 16  wherein the polar solvent is selected from the group consisting of glycols, alcohols, esters, ethers, carboxylic acids, amines, organic compounds containing one or more polar functional groups, and mixtures thereof. 
     
     
         19 . The method of  claim 16  wherein the one or more polar lubricating oil additives are selected from the group consisting of friction modifiers, antioxidants, corrosion inhibitors, rust inhibitors, metal deactivators, anti-wear agents and/or extreme pressure additives, dispersants, detergents, anti-seizure agents, wax modifiers, viscosity index improvers, viscosity modifiers, fluid-loss additives, seal compatibility agents, lubricity agents, anti-staining agents, chromophoric agents, defoamants, demulsifiers, emulsifiers, densifiers, wetting agents, gelling agents, tackiness agents, colorants, antifoam agents, and pour point depressants. 
     
     
         20 . The method of  claim 16  wherein the one or more polar lubricating oil additives comprise one or more friction modifiers, antioxidants, corrosion inhibitors, rust inhibitors, or mixtures thereof. 
     
     
         21 . The method of  claim 16  wherein the surfactant comprises a succinimide, a succinate ester, a succinate ester amide, a hydrocarbyl-substituted succinic acid derivative, a hydrocarbyl-substituted succinic anhydride derivative, an alkenylsuccinic derivative, or mixtures thereof. 
     
     
         22 . The method of  claim 16  wherein the surfactant comprises a succinate ester, a phenate, a sulfonate, a sulfurized phenate, a salicylate, a naphthenate, a stearate, a carbamate, a thiocarbamate, a phosphorus derivative, or mixtures thereof. 
     
     
         23 . The method of  claim 16  wherein the surfactant comprises polyisobutylene succinimide polyamine (PIBSA-PAM). 
     
     
         24 . The method of  claim 16  wherein the swollen inverse micelles have a diameter of between 0.01 μm and 1 μm. 
     
     
         25 . The method of  claim 16  wherein the nonpolar lubricating oil base stock is present in an amount from 70 weight percent to 95 weight percent, and the one or more polar lubricating oil additives are present in an amount from 0.1 weight percent to 10 weight percent or greater, based on the total weight of the lubricating oil. 
     
     
         26 . The method of  claim 16  wherein the solubility of the polar lubricating oil additives in the nonpolar lubricating oil base stock is improved as compared to solubility achieved using a lubricating oil containing polar lubricating oil additives in a nonpolar lubricating oil base stock and not containing said swollen inverse micelles. 
     
     
         27 . The method of  claim 26  wherein the one or more polar lubricating oil additives comprise one or more inorganic friction modifiers, antioxidants, corrosion inhibitors, rust inhibitors, or mixtures thereof. 
     
     
         28 . The method of  claim 16  wherein surface performance in an engine is improved as compared to surface performance in an engine using a lubricating oil containing polar lubricating oil additives in a nonpolar lubricating oil base stock and not containing said swollen inverse micelles. 
     
     
         29 . The method of  claim 28  wherein surface performance comprises increasing thickness of a lubricating film at contacts requiring elastohydrodynamic lubrication (EHL) in said engine. 
     
     
         30 . The method of  claim 16  in which the lubricating oil is used in automotive, marine, aviation, and industrial engine and machine component applications. 
     
     
         31 . A method of improving surface performance of a lubricating oil in an engine lubricated with the lubricating oil, said method comprising using as the lubricating oil a formulated oil comprising a nonpolar lubricating oil base stock as a major component and one or more polar lubricating oil additives as a minor component; wherein said one or more polar lubricating oil additives comprise swollen inverse micelles dispersed in said nonpolar lubricating oil base stock; and wherein said swollen inverse micelles comprise (i) a liquid polar core containing a polar solvent and one or more polar lubricating oil additives having solubility in said polar solvent, and (ii) a layer of liquid surfactant molecules enclosing said liquid polar core in which polar heads of the liquid surfactant molecules are oriented towards the liquid polar core. 
     
     
         32 . The method of  claim 31  wherein the nonpolar lubricating oil base stock comprises a Group I, Group II, Group III, Group IV or Group V base oil. 
     
     
         33 . The method of  claim 31  wherein the polar solvent is selected from the group consisting of glycols, alcohols, esters, ethers, carboxylic acids, amines, organic compounds containing one or more polar functional groups, and mixtures thereof. 
     
     
         34 . The method of  claim 31  wherein the one or more polar lubricating oil additives are selected from the group consisting of friction modifiers, antioxidants, corrosion inhibitors, rust inhibitors, metal deactivators, anti-wear agents and/or extreme pressure additives, dispersants, detergents, anti-seizure agents, wax modifiers, viscosity index improvers, viscosity modifiers, fluid-loss additives, seal compatibility agents, lubricity agents, anti-staining agents, chromophoric agents, defoamants, demulsifiers, emulsifiers, densifiers, wetting agents, gelling agents, tackiness agents, colorants, antifoam agents, and pour point depressants. 
     
     
         35 . The method of  claim 31  wherein the one or more polar lubricating oil additives comprise one or more friction modifiers, antioxidants, corrosion inhibitors, rust inhibitors, or mixtures thereof. 
     
     
         36 . The method of  claim 31  wherein the surfactant comprises a succinimide, a succinate ester, a succinate ester amide, a hydrocarbyl-substituted succinic acid derivative, a hydrocarbyl-substituted succinic anhydride derivative, an alkenylsuccinic derivative, or mixtures thereof. 
     
     
         37 . The method of  claim 31  wherein the surfactant comprises a succinate ester, a phenate, a sulfonate, a sulfurized phenate, a salicylate, a naphthenate, a stearate, a carbamate, a thiocarbamate, a phosphorus derivative, or mixtures thereof. 
     
     
         38 . The method of  claim 31  wherein the surfactant comprises polyisobutylene succinimide polyamine (PIB SA-PAM). 
     
     
         39 . The method of  claim 31  wherein the swollen inverse micelles have a diameter of between 0.01 μm and 1 μm. 
     
     
         40 . The method of  claim 31  wherein the nonpolar lubricating oil base stock is present in an amount from 70 weight percent to 95 weight percent, and the one or more polar lubricating oil additives are present in an amount from 0.1 weight percent to 10 weight percent or greater, based on the total weight of the lubricating oil. 
     
     
         41 . The method of  claim 31  wherein the solubility of the polar lubricating oil additives in the nonpolar lubricating oil base stock is improved as compared to solubility achieved using a lubricating oil containing polar lubricating oil additives in a nonpolar lubricating oil base stock and not containing said swollen inverse micelles. 
     
     
         42 . The method of  claim 41  wherein the one or more polar lubricating oil additives comprise one or more inorganic friction modifiers, antioxidants, corrosion inhibitors, rust inhibitors, or mixtures thereof. 
     
     
         43 . The method of  claim 31  wherein surface performance in an engine is improved as compared to surface performance in an engine using a lubricating oil containing polar lubricating oil additives in a nonpolar lubricating oil base stock and not containing said swollen inverse micelles. 
     
     
         44 . The method of  claim 43  wherein surface performance comprises increasing thickness of a lubricating film at contacts requiring elastohydrodynamic lubrication (EHL) in said engine. 
     
     
         45 . The method of  claim 31  in which the lubricating oil is used in automotive, marine, aviation, and industrial engine and machine component applications. 
     
     
         46 . A swollen inverse micelle composition comprising (i) a liquid polar core containing a polar solvent and one or more polar lubricating oil additives having solubility in said polar solvent, and (ii) a layer of liquid surfactant molecules enclosing said liquid polar core in which polar heads of the liquid surfactant molecules are oriented towards the liquid polar core. 
     
     
         47 . A process for making a swollen inverse micelle composition, said process comprising:
 providing one or more polar lubricating oil additives, a polar solvent, and a surfactant; and   mixing the one or more polar lubricating oil additives, the polar solvent, and the surfactant under conditions sufficient to form the swollen inverse micelle composition;   wherein the swollen inverse micelle composition comprises (i) a liquid polar core containing the polar solvent and the one or more polar lubricating oil additives having solubility in said polar solvent, and (ii) a layer of liquid surfactant molecules enclosing said liquid polar core in which polar heads of the liquid surfactant molecules are oriented towards the liquid polar core.   
     
     
         48 . A lubricating oil comprising a nonpolar lubricating oil base stock as a major component and a polar lubricating oil additive as a minor component; wherein said polar lubricating oil additive comprises swollen inverse micelles dispersed in said nonpolar lubricating oil base stock; and wherein said swollen inverse micelles comprise (i) a liquid polar core containing a polar solvent and an antioxidant having solubility in said polar solvent, and (ii) a layer of liquid surfactant molecules enclosing said liquid polar core in which polar heads of the liquid surfactant molecules are oriented towards the liquid polar core. 
     
     
         49 . A lubricating oil comprising a nonpolar lubricating oil base stock as a major component and a mixture of polar lubricating oil additives as a minor component; wherein said mixture of polar lubricating oil additives comprises swollen inverse micelles dispersed in said nonpolar lubricating oil base stock; and wherein said mixture of swollen inverse micelles comprises: (a) a liquid polar core containing a polar solvent and an antioxidant having solubility in said polar solvent, and a layer of liquid surfactant molecules enclosing said liquid polar core in which polar heads of the liquid surfactant molecules are oriented towards the liquid polar core; and (b) a liquid polar core containing a polar solvent and a friction modifier having solubility in said polar solvent, and a layer of liquid surfactant molecules enclosing said liquid polar core in which polar heads of the liquid surfactant molecules are oriented towards the liquid polar core. 
     
     
         50 . A lubricating oil comprising a nonpolar lubricating oil base stock as a major component and a mixture of polar lubricating oil additives as a minor component; wherein said mixture of polar lubricating oil additives comprises (a) a first friction modifier comprising an organometallic molybdenum compound, and (b) a second friction modifier comprising swollen inverse micelles dispersed in said nonpolar lubricating oil base stock; wherein said swollen inverse micelles comprises a liquid polar core containing a polar solvent and an inorganic molybdate compound having solubility in said polar solvent, and a layer of liquid surfactant molecules enclosing said liquid polar core in which polar heads of the liquid surfactant molecules are oriented towards the liquid polar core; and wherein friction reduction and fuel efficiency are maintained or improved as compared to friction reduction and fuel efficiency achieved with a lubricating engine oil using singly the first friction modifier or the second friction modifier, as measured by one or more of ASTM D6079, SEQ VI-D and SEQ VI-E.