Additive Composition

Abstract

An additive composition is disclosed. The additive composition includes a lubricity enhancer and a conductivity-improving additive. The lubricity enhancer comprises a salt formed by the reaction of a carboxylic acid with di-n-butylamine and the conductivity improving additive is the combination of: (a) a polymeric condensation product formed by the reaction of an aliphatic aldehyde or ketone, or a reactive equivalent, with at least one ester of p-hydroxybenzoic acid with, (b) a copolymer, terpolymer or polymer of acrylic acid or methacrylic acid or a derivative thereof.

1 . An additive composition comprising a lubricity enhancer and a conductivity-improving additive; wherein the lubricity enhancer comprises a salt formed by the reaction of a carboxylic acid with di-n-butylamine; and wherein the conductivity improving additive comprises the combination of,
 (a) a polymeric condensation product formed by the reaction of an aliphatic aldehyde or ketone, or a reactive equivalent, with at least one ester of p-hydroxybenzoic acid with,   (b) a copolymer, terpolymer or polymer of acrylic acid or methacrylic acid or a derivative thereof.   
     
     
         2 . The additive composition according to  claim 1 , wherein the carboxylic acid comprises a fatty acid or a mixture of fatty acids. 
     
     
         3 . The additive composition according to  claim 1 , wherein the at least one ester of p-hydroxybenzoic acid comprises; (i) a straight or branched chain C 1 -C 7  alkyl ester of p-hydroxybenzoic acid; (ii) a branched chain C 8 -C 16  alkyl ester of p-hydroxybenzoic acid, or; (iii) a mixture of long chain C 8 -C 18  alkyl esters of p-hydroxybenzoic acid, at least one of said alkyls being branched. 
     
     
         4 . The additive composition according to  claim 1 , wherein the copolymer, terpolymer or polymer of acrylic acid or methacrylic acid or a derivative thereof is copolymerized with a nitrogen-containing, amine-containing or amide-containing monomer; or includes nitrogen-containing, amine-containing or amide-containing branches. 
     
     
         5 . A fuel oil composition comprising a major proportion of a fuel oil and a minor proportion of an additive composition comprising a lubricity enhancer and a conductivity-improving additive; wherein the lubricity enhancer comprises a salt formed by the reaction of a carboxylic acid with di-n-butylamine; and wherein the conductivity improving additive comprises the combination of:
 (a) a polymeric condensation product formed by the reaction of an aliphatic aldehyde or ketone, or a reactive equivalent, with at least one ester of p-hydroxybezoic acid with,   (b) a copolymer, terpolymer or polymer of acrylic acid or methacrylic acid or a derivative thereof.   
     
     
         6 . The fuel oil composition according to  claim 5 , wherein the fuel oil comprises a middle distillate fuel oil having a sulphur content of at most 0.05% by weight. 
     
     
         7 . The fuel oil composition according to  claim 5  having a conductivity which is at least 50% of the conductivity of an equivalent fuel oil composition containing the same quantity of the conductivity-improving additive, in the absence of the lubricity enhancer. 
     
     
         8 . A method for improving the lubricity of a fuel oil comprising: adding an additive composition according to  claim 1  to a fuel oil having a sulphur content of at most 0.05% by weight.