| abstract |
The present invention provides a lubricating composition comprising: a base oil; one or more poly (hydroxycarboxylic acid) amide salt derivatives having Formula (III) : [Y-CO [O-A-CO] n -Z-R + ]m pX q- wherein Y is hydrogen or an optionally substituted hydrocarbyl group, A is a divalent optionally substituted hydrocarbyl group, n is from 1 to 100, preferably from 1 to 10, m is from 1 to 4, q is from 1 to 4 and p is an integer such that pq = m, Z is an optionally substituted divalent bridging group which is attached to the carbonyl group through a nitrogen atom, R + is an ammonium group and X q- is an anion; and one or more detergents; wherein the soap concentration as provided by a detergent selected from the group of sulphonate and salicylate detergents is less than 3.75 mmol soap per wt.% of the one or more poly (hydroxycarboxylic acid) amide salt derivatives having Formula (III). |