VISCOSITY MODIFIER FOR LUBRICATING OILS, ADDITIVE COMPOSITION FOR LUBRICATING OILS, AND LUBRICATING OIL COMPOSITIONS

摘要

[Problems];An object of the present invention is to provide a viscosity modifier for lubricating oils and an additive composition for lubricating oils, for obtaining a lubricating oil composition excellent in storage stability under low temperature conditions as well as in viscosity characteristics at a low temperature.;[Solution to Problems];The viscosity modifier for lubricating oils according to the present invention contains a resin (α), wherein the resin (α) satisfies specific requirements, and contains a grafted olefin polymer [R1] which is composed of a main chain and a side chain(s) and which satisfies the following requirements (i) and (ii). (i) The main chain is composed of a copolymer of ethylene and at least one α-olefin selected from α-olefins having from 3 to 12 carbon atoms, and contains the structural units derived from ethylene within the range of from 74 to 86 mol%. (ii) The side chain(s) is/are composed of a copolymer of ethylene and at least one α-olefin selected from α-olefins having from 3 to 12 carbon atoms, and contain(s) the structural units derived from ethylene within the range of from 30 to 65 mol%.