JP2010065072A5 - - Google Patents

Claims (4)

A lubricating oil composition for gear oil comprising a lubricating base oil (A) and an α-olefin (co) polymer (B) defined by the following (i) to (vi), the lubricating oil composition: The lubricating oil composition for gear oils containing 5-40 mass% of (alpha) -olefin (co) polymer (B) with respect to this.
Lubricating base oil (A);
Viscosity index is 110 or more and kinematic viscosity at 100 ° C. is ² to 7 mm ² / s
α-olefin (co) polymer (B);
(I) (a) a structural unit derived from at least one monomer selected from α-olefins having 8 to 20 carbon atoms in a range of 90 to 100 mol% and (b) a structural unit derived from ethylene. In the range of 0 to 10 mol%,
(Ii) a kinematic viscosity at 100 ° C. in the range of 550 to 2000 mm ² / s,
(Iii) Number average molecular weight (Mn) is in the range of 6000-30000,
(Iv) a molecular weight distribution (Mw / Mn) in the range of 1.1 to 1.8;
(V) The content of unsaturated groups at the molecular end is 10% or less, and (vi) the viscosity index satisfies the following formula (1).
Viscosity index ≧ 37.59 ln (kinematic viscosity at 100 ° C.) + 23.08 Formula (1)
(However, ln (kinematic viscosity at 100 ° C.) is the natural logarithm of kinematic viscosity at 100 ° C.)   The lubricating oil composition for gear oil according to claim 1, wherein the α-olefin having 8 to 20 carbon atoms is 1-decene.   The lubricating oil composition for gear oil further comprises a compatibilizer, detergent dispersant, antioxidant, corrosion inhibitor, antiwear agent, friction modifier, pour point depressant, rust inhibitor, antifoaming agent and extreme pressure. The gear oil lubricating oil composition according to claim 1 or 2, comprising at least one additive selected from the group consisting of agents. Kinematic viscosity at 40 ° C. is not more than 80 mm ² / s, and a gear oil according to claim 1 in the range kinematic viscosity of 13.5~14.5mm ² / s at 100 ° C. Lubricating oil composition.