Lubricating Oil Composition

Abstract

A lubricating oil composition including at least one sulphurized overbased metal phenate detergent prepared from a C 9 -C 15 alkyl phenol, at least one sulphurizing agent, at least one metal and at least one overbasing agent. The detergent includes less than 6.0% by combined mass of unsulphurized C 9 -C 15 alkyl phenol and its unsulphurized metal salt. The lubricating oil composition exhibits an improved rate of acid neutralization.

1 . A lubricating oil composition including at least one sulphurized overbased metal phenate detergent prepared from a C 9 -C 15  alkyl phenol, at least one sulphurizing agent, at least one metal and at least one overbasing agent; the detergent including less than 6.0% by combined mass of unsulphurized C 9 -C 15  alkyl phenol and unsulphurized metal salts thereof. 
     
     
         2 . The composition as claimed in  claim 1 , wherein the sulphurized overbased metal phenate detergent is prepared from a C 10 -C 13  alkyl phenol. 
     
     
         3 . The composition as claimed in  claim 1 , wherein the sulphurized overbased metal phenate detergent also includes at least one further surfactant selected from a sulphonic acid or a carboxylic acid. 
     
     
         4 . The composition as claimed in  claim 3 , wherein the sulphurized overbased metal phenate detergent includes stearic acid as a further surfactant. 
     
     
         5 . The composition as claimed in  claim 1 , wherein the sulphurizing agent is sulphur monochloride. 
     
     
         6 . The composition as claimed in  claim 1 , wherein the metal is calcium. 
     
     
         7 . The composition as claimed in  claim 1 , wherein the overbased metal phenate detergent has been prepared using a carbonation temperature of less than 100° C., preferably less than 80° C. 
     
     
         8 . The composition as claimed in  claim 7 , wherein the overbased metal phenate detergent has been prepared using a carbonation temperature of less than 80° C. 
     
     
         9 . The composition as claimed in  claim 1 , wherein the overbasing agent is carbon dioxide. 
     
     
         10 . A method of increasing the rate of acid neutralization of a lubricating oil composition, the method including the step of adding to the lubricating oil composition at least one sulphurized overbased metal phenate detergent prepared from a C 9 -C 15  alkyl phenol, at least one sulphurizing agent, at least one metal and at least one overbasing agent; the sulphurized overbased metal phenate detergent including less than 6.0% by combined mass of unsulphurized C 9 -C 15  alkyl phenol and unsulphurized metal salts thereof.