LUBRICATING OIL ADDITIVES

A composition prepared by reacting(A) an esterified carboxy-containing interpolymer, said interpolymer being derived from at least two monomers, (i) one of said monomers being at least one vinyl aromatic monomer and (ii) the other of said monomers being at least one alpha, beta-unsaturated acylating agent, and having, before esterification, {overscore (M)}n determined by gel permeation chromatography ranging from about 8,000 to about 350,000, wherein from about 80% to about 99% of the carboxylic groups of said interpolymer are esterified, wherein from about 80 to about 100% of the ester groups contain from 8 to about 23 carbon atoms and from 0 to about 20% of the ester groups contain from 2 to 7 carbon atoms, with(B) a hydrocarbyl substituted carboxylic acid or functional derivative thereof wherein the hydrocarbyl group comprises from about 10 to about 400 carbon atoms, and (C) an amine having an average of more than 1 condensable N-H group, in any order or simultaneously, or with the preformed reaction product of (B) and (C) wherein said preformed reaction product has at least one condensable N-H group. Depending upon the relative amounts of reactant (A) and (B) used, a composition which acts primarily as a viscosity improver with dispersant properties (DVM) or primarily as a dispersant with viscosity improving properties (VMD) may be prepared or compositions with properties intermediate between these.