Patent ID: 8293689

Claim:
A lubricating composition comprising: (a) an oil of lubricating viscosity; (b) a polymer of Formula (I), wherein the polymer has pendant groups as represented within ( ) w of the formula: wherein BB is a polymer backbone, wherein the polymer is a poly(meth)acrylate; X is a functional group which either (i) contains at least one carbon and at least one oxygen or nitrogen atom, (ii) contains at least one acylating agent, or (iii) is an alkylene group with about 1 to about 5 carbon atoms, connecting the polymer backbone and a branched hydrocarbyl group contained within ( ) y ; w is the number of pendant groups attached to the polymer backbone in the range of about 1 to about 2000; y is 0, 1, 2 or 3, provided that in at least 1 mol % of the pendant groups, y is not zero; and with the proviso that when y is 0, X is bonded to a terminal group in a manner sufficient to satisfy the valence of X, wherein the terminal group is selected from hydrogen, alkyl, aryl, a metal or ammonium cation, and mixtures thereof; p is an integer in the range of about 1 to about 15; R′ and R″ are independently linear or branched hydrocarbyl groups, and the combined total number of carbon atoms present on R′ and R″ is at least about 12, wherein a steric hindrance factor F that is defined by the equation: F= 4 U+Y wherein F is the steric hindrance factor; U and Y represent the total atom numbers at the 6th position and the 7th position, respectively, in the side chain(s), counted from the backbone, and wherein the steric hindrance factor is about 20 to about 30; and (c) 0.05 wt % to about 10 wt % of an antiwear agent, wherein the antiwear agent is ashless.