Patent ID: 8288327

Claim:
A lubricant composition having good frictional properties, comprising: a base oil and at least one additive having friction-modifying properties, wherein the additive having friction-modifying properties is a block copolymer comprising: hydrophobic segments P and polar segments D, wherein the hydrophobic segments are obtained by polymerization of monomer compositions which comprises a) from 0.5 to 40% by weight, based on the weight of the monomer compositions for preparing the hydrophobic segments, of one or more ethylenically unsaturated ester compounds of the formula (I): wherein R is hydrogen or methyl, R 1 is a linear or branched alkyl radical having from 1 to 5 carbon atoms, R 2 and R 3 are each independently hydrogen or a group of the formula â€”COORâ€² in which Râ€² is hydrogen or an alkyl group having from 1 to 5 carbon atoms, b) from 50 to 99.5% by weight, based on the weight of the monomer compositions for preparing the hydrophobic segments, of one or more ethylenically unsaturated ester compounds of the formula (II): wherein R is hydrogen or methyl, R 4 is a linear or branched alkyl radical having from 6 to 30 carbon atoms, R 5 and R 6 are each independently hydrogen or a group of the formula â€”COORâ€³ in which Râ€³ is hydrogen or an alkyl group having from 6 to 30 carbon atoms, c) from 0 to 50% by weight, based on the weight of the monomer compositions for preparing the hydrophobic segments, of comonomers, and the polar segments are represented by the formula (III): wherein R is independently hydrogen or methyl, R 7 is independently a group comprising from 2 to 1000 carbon atoms and having at least one heteroatom, X is independently a sulfur or oxygen atom or a group of the formula NR 8 in which R 8 is independently hydrogen or a group having from 1 to 20 carbon atoms, and n is an integer greater than or equal to 3, and further wherein a ratio of the length of the hydrophobic segments to the polar segments of the block copolymer is in the range of from 5:1 to 1:2.