Antiwear Composition and Method of Lubricating an Internal Combustion Engine

Abstract

The present invention relates to a lubricating composition containing an oil of lubricating viscosity and an antiwear package. The antiwear package may contain a derivative of a hydroxycarboxylic acid; and a salt of a sulphur-free phosphorus-containing compound. The salt includes amine salts, ammonium salts, metal salts and mixtures thereof. The invention further provides for a method of supplying an internal combustion engine with the lubricating composition.

1 - 19 . (canceled) 
     
     
         20 . A lubricating composition comprising an oil of lubricating viscosity and an antiwear package, wherein the antiwear package comprises:
 (a) 0.25 to 2.5 wt % of an antiwear agent represented by a compound of Formula (1a) and/or (1b):   
       
         
           
           
               
               
           
         
       
       wherein
 n′ is 0 to 10 for Formula (1b), and 1 to 10 for Formula (1a); 
 p is 1 to 5; 
 Y and Y′ are independently —O—, >NH, >NR 3 , or an imide group formed by taking together both Y and Y′ groups in (1b) or two Y groups in (1a) and forming a R′—N< group between two >C═O groups; 
 X is independently —CH 2 —, >CHR 4 , >CR 4 R 5 , >CHOR 6 , >C(CO 2 R 6 ) 2 , —CH 3 , CH 2 R 4 , —CHR 4 R 5 , —CH 2 OR 6 , —CH(CO 2 R 6 ) 2 , >C(OR 6 )CO 2 R 6 , >CHCO 2 R 6 , or ≡C—R 6  or mixtures thereof to fulfill the valence of Formula (1a) and/or (1b); 
 R 1  and R 2  are independently hydrocarbyl groups, containing 1 to 150 carbon atoms; 
 R 3  is a hydrocarbyl group; 
 R 4  and R 5  are independently keto-containing groups, ester groups or hydrocarbyl groups; and 
 R 6  is independently hydrogen or a hydrocarbyl group; and 
 (b) 0.25 to 2.5 wt % of a salt of a sulphur-free phosphorus-containing compound. 
 
     
     
         21 . The lubricating composition of  claim 20 , wherein sulphur-free phosphorus-containing compound is a phosphorylated dispersant. 
     
     
         22 . The lubricating composition of  claim 21 , wherein the phosphorylated dispersant is a nitrogen-containing dispersant selected from the group consisting of:
 (i) hydrocarbyl-substituted succinimides;   (ii) mixed ester/amides of hydrocarbyl-substituted succinic acid made using alkanois, amines, and/or aminoalkanols;   Mannich dispersants which are condensation products of hydrocarbyl-substituted phenols, formaldehyde and polyethylene polyamines; and   (iv) mixtures thereof.   
     
     
         23 . The lubricating composition of  claim 22 , wherein the nitrogen-containing dispersant is a polyisobutylene succinimide with number average molecular weight of the polyisobutylene substituent in the range 500 to 3000. 
     
     
         24 . The lubricating composition of  claim 20 , wherein the compound of Formula (1a) and/or (1b) is a derivative of a hydroxycarboxylic acid. 
     
     
         25 . The lubricating composition of  claim 20 , wherein X is hydroxyl-containing, and the compound Formula (1a) and/or (1b) is derived from hydroxycarboxylic acids selected from the group consisting of tartaric acid, citric acid, and mixtures thereof. 
     
     
         26 . The lubricating composition of  claim 20 , wherein X is hydroxyl-containing, and the compound Formula (1a) and/or (1b) is derived from tartaric acid. 
     
     
         27 . The lubricating composition of  claim 20 , wherein the compound Formula (1a) and/or (1b) is an imide, a di-ester, a di-amide, or an ester-amide derivative of tartaric acid. 
     
     
         28 . A method for lubricating an internal combustion engine comprising supplying to the engine a lubricating composition of  claim 20 . 
     
     
         29 . The method of  claim 28 , wherein the internal combustion engine is a 2-stroke engine. 
     
     
         30 . The method of  claim 28 , wherein the internal combustion engine is a 4-stroke engine. 
     
     
         31 . The method of  claim 28 , wherein the lubricating composition has (i) a sulphur content of 0.5 wt % or less, (ii) a phosphorus content of 0.07 wt % or less, and (iii) a sulphated ash content of 1.5 wt % or less. 
     
     
         32 . The method of  claim 28 , wherein the lubricating composition has a sulphur content in the range of 0.001 wt % to 0.5 wt %. 
     
     
         33 . The lubricating composition of  claim 20 , wherein of the salt of a sulphur-free phosphorus-containing compound is represented Formula (2): 
       
         
           
           
               
               
           
         
       
       wherein
 A and A′ are independently H, or a hydrocarbyl group containing 1 to 30 carbon atoms; 
 each R and R″ group are independently a hydrocarbyl group; 
 each R′ is independently R, H, or a hydroxyalkyl group; 
 Y is independently R′, or a group represented by RO(R′O)P(O)—CH(A′)CH(A)-; 
 x′ ranges from 0 to 1; and 
 m and n are both positive non-zero integers, with the proviso that the sum of (m+n) is equal to 4; 
 M is a metal ion; 
 t is an integer varying from 1 to 4; and 
 q and e are fractions, whose total provides complete valence to satisfy t, with the proviso that q is in the range of 0.1 to 1.5, and e is in the range of 0 to 0.9. 
 
     
     
         34 . The lubricating composition of  claim 33 , wherein the compound of Formula (2) is free of a metal ion (e is equal to zero and q is equal to one). 
     
     
         35 . A method for lubricating an internal combustion engine comprising supplying to the engine a lubricating composition of  claim 33 . 
     
     
         36 . The method of  claim 35 , wherein the internal combustion engine is a 2-stroke engine. 
     
     
         38 . The method of  claim 35 , wherein the internal combustion engine is a 4-stroke engine. 
     
     
         38 . The method of  claim 35 , wherein the lubricating composition has (i) a sulphur content of 0.5 wt % or less, (ii) a phosphorus content of 0.07 wt % or less, and (iii) a sulphated ash content of 1.5 wt % or less. 
     
     
         39 . The method of  claim 35 , wherein the lubricating composition has a sulphur content in the range of 0.001 wt % to 0.5 wt %.