Dispersant viscosity modifiers with sulfonate functionality

Abstract

A lubricating composition includes an oil of lubricating viscosity and an oil-soluble dispersant viscosity modifier, which includes an olefin-based polymer backbone and at least one pendent functional group. Each of the at least one pendent functional group is independently attached to the olefin-based polymer backbone by a linking group. The at least one pendent functional group includes a sulfonate moiety.

1 . A lubricating composition comprising:
 an oil of lubricating viscosity; and   at least 0.05 wt. % of an oil-soluble dispersant viscosity modifier comprising an olefin-based polymer backbone and at least one pendent functional group selected from alkyl and aryl sulfonate salts, alkyl and aryl sulfonic acids, and combinations thereof, the olefin-based polymer backbone comprising an ethylene-olefin-based copolymer, each of the at least one pendent functional group being independently attached to the olefin-based polymer backbone by a linking group, the at least one pendent functional group comprising a sulfonate moiety, wherein the at least one pendent functional group is derived from a sulfonated hydrocarbyl compound selected from the group consisting of:   
       
         
           
           
               
               
           
         
         where c is from 1-10, 
         d is from 1-10, 
         e is at least 1, 
         B is NH 2  or OH, 
         R 11 , R 12 , R 13  and R 14  are independently H or a C 1  to C 30  alkyl group, and 
         R 15 , R 16 , R 17 , and R 18  are independently selected from H, OH, NH 2 , alkyl groups, and alkoxy groups. 
       
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . The lubricating composition of  claim 1 , wherein the at least one pendent functional group is derived from a cyclic sulfonic acid ester. 
     
     
         5 . The lubricating composition of  claim 1 , wherein the at least one pendent functional group is derived from a sulfonated hydrocarbyl compound of the general form:
   B-A-SO 3 M   where A represents a hydrocarbyl group, B represents a functional group capable of reaction with the linking group or with an intermediate linker unit, and M represents a monovalent cation.   
     
     
         6 . (canceled) 
     
     
         7 . The lubricating composition of  claim 1 , wherein the sulfonated hydrocarbyl compound is selected from the group consisting of 3-hydroxypropane-1-sulfonic acid, 3-amino-1-propane sulfonic acid, homocysteic acid, 1,3-propanesultone, 1,4-butanesultone, p-aminobenzenesulfonic acid, 7-amino-1,3-naphthene disulfonic acid, 8-(2-aminoethylamino)-1-naphthene sulfonic acid, and mixtures thereof. 
     
     
         8 . The lubricating composition of  claim 1 , wherein the sulfonate moiety is spaced from the olefin-based polymer backbone by a C 4 -C 24  hydrocarbyl group. 
     
     
         9 . (canceled) 
     
     
         10 . The lubricating composition of  claim 1 , wherein at least some of the linking groups are derived from an ethylenically unsaturated carboxylic acid monomer. 
     
     
         11 . The lubricating composition of  claim 10 , wherein the ethylenically unsaturated carboxylic acid monomer is selected from maleic anhydride, maleic anhydrides, chlormaleic anhydride, itaconic anhydride, and corresponding dicarboxylic acids and esters thereof, alkyl-substituted derivatives thereof, and mixtures thereof. 
     
     
         12 . The lubricating composition of  claim 10 , wherein the linking groups are attached to the pendent groups by linker units derived from at least one of hydroxyl alkyl amines, alkylene polyamines, and polyols. 
     
     
         13 . The lubricating composition of  claim 12 , wherein at least some of the linking groups are derived from maleic anhydride and at least some of the linker units are derived from a hydroxyl alkyl amine. 
     
     
         14 . The lubricating composition of  claim 1 , wherein the sulfonate moiety comprises a sulfonate salt which includes a cation of the general form —(NR 3 R 4 R 5 ), where R 3 , R 4 , and R 5  are independently selected from H and C 1  to C 30  alkyl groups. 
     
     
         15 . The lubricating composition of  claim 1 , wherein a ratio by weight of linking groups to the polymer backbone in the dispersant viscosity modifier is at least 1:100. 
     
     
         16 . (canceled) 
     
     
         17 . (canceled) 
     
     
         18 . The lubricating composition of  claim 1 , wherein the dispersant viscosity modifier comprises at least two of the pendent functional groups per molecule of the dispersant viscosity modifier, on average. 
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . The lubricating composition of  claim 1 , wherein the olefin-based polymer backbone comprises an ethylene-olefin-based copolymer. 
     
     
         22 . (canceled) 
     
     
         23 . The lubricating composition of  claim 1 , wherein the olefin-based polymer backbone has a number average molecular weight, as measured by gel permeation chromatography, using a polystyrene standard, of greater than at least 1000. 
     
     
         24 . (canceled) 
     
     
         25 . The lubricating composition of  claim 1 , wherein the oil of lubricating viscosity is present in the composition at a concentration of at least 10 wt. %. 
     
     
         26 . (canceled) 
     
     
         27 . (canceled) 
     
     
         28 . (canceled) 
     
     
         29 . The lubricating composition of  claim 1 , wherein the composition further comprises at least one of a dispersant, a detergent, an overbased detergent, an antioxidant a viscosity modifier, a friction modifier, a corrosion inhibitor, a pour point depressant, a seal swell agent, a demulsifier, and an antiwear agent. 
     
     
         30 . (canceled) 
     
     
         31 . A process for making a lubricating composition comprising:
 (i) providing an olefin-based polymer backbone with one or more acylating linking groups, each independently attached along the polymer backbone;   (ii) optionally, reacting each acylating group with a hydroxy alkyl amine, an alkylene polyamine, a polyol, or a combination thereof, resulting in an olefin-based polymer with one or more linker units each independently attached along the polymer backbone; and   (iii) reacting each linking group or linker unit with a hydrocarbyl sulfonate compound selected from sulfonate salts and sulfonic acids, resulting in a dispersant viscosity modifier comprising one or more pendent hydrocarbyl sulfonate groups each independently attached to the olefin-based polymer.   
     
     
         32 . The process of  claim 31 , wherein the providing of the olefin-based polymer with one or more acylating linking groups comprises grafting one or more unsaturated carboxylic reactants onto an olefin-based polymer backbone. 
     
     
         33 . The process of  claim 31 , wherein hydrocarbyl sulfonate compound is selected from sulfonated hydrocarbyl compounds of the general form:
   B-A-SO 3 M   where A represents a hydrocarbyl group, B represents a functional group capable of reaction with the acylating linking groups or linker units, and M represents a monovalent cation.   
     
     
         34 . A method of lubricating an internal combustion engine comprising supplying the lubricating composition of  claim 1  to the internal combustion engine.