The purpose of the present invention is to provide: a
friction modifier capable of achieving both an antifriction effect and storage stability; and a lubricating oil composition containing the
friction modifier, the lubricating oil composition having a high antifriction effect and high high-temperature stability. The present invention pertains to a
friction modifier containing a
copolymer (A) having, as essential constituent monomers, a
monomer (a) represented by general formula (1) and a
monomer (b) represented by general formula (2), the average value of p per mole of the
monomer (a) among the monomers constituting the
copolymer (A) being 1-4, the weight-average molecular weight of the
copolymer (A) being 50,000-380,000, and the average value of p per mole of the monomer (a) being 1-4. The copolymer (A) contains, as a constituent monomer, 10-60 wt% of the monomer (a) based on the total weight of the monomers constituting the copolymer (A). [In general formula (1), A1 represents a polymerizable group; -X < 1->,-X < 2-> and-X < 3-> are each independently a group represented by-O-or-NH-; r1 represents an alkylene group having 1 to 4 carbon atoms; r2 is an alkylene group having 2 to 20 carbon atoms; r3 is a
hydrogen atom; and p is an integer from 1 to 100, and when p is 2 or more, the plurality of R2 and X3 are the same or different. ] [In general formula (2), R4 is a
hydrogen atom or a
methyl group; -X4 <-> is a group represented by-O <-> or-NH <->; and R5 is a
straight chain or branched chain
alkyl group with 5-44 carbon atoms. ]. # imgabs0 #