Viscosity Modifier For Lubricating Oil, And Lubricating Oil Composition For Hydraulic Oil

Abstract: Provided are: a viscosity modifier for a lubricating oil, which has excellent temperature viscosity characteristics, i.e., oil film retainability at high temperatures and low-temperature viscosity characteristics, and which has excellent handling properties for continuously maintaining the long-term use performance of a hydraulic system; and a lubricating oil composition for hydraulic oils such as a hydraulic oil for machine tools, a hydraulic oil for molding machines, and a hydraulic oil for construction machines, which has excellent energy-saving properties. The viscosity modifier for a lubricating oil comprises (C) an ethylene-a-olefin copolymer having an ethylene molar content in the range of 30-70 mol%, a rotational viscosity at 150 °C of 300-8,000 mPa·s, a Hazen chromaticity of 30 or less, a molecular weight distribution (Mw/Mn) of 2.5 or less, and a B value of 1.1 or more. The lubricating oil composition for hydraulic oils contains the viscosity modifier for a lubricating oil and a lubricating oil-based oil comprising: (A) a mineral oil having a kinematic viscosity at 40 °C of 10-100 mm2/s, a viscosity index of 90 or more, and a pour point of 0 °C or less; and/or (B) a synthetic oil having a kinematic viscosity at 40 °C of 4-100 mm2/s, a viscosity index of 90 or more, and a pour point of -30 °C or less, and has a kinematic viscosity at 40 °C of 28-170 mm2/s.

Patent Information

Applicants

Inventors

Specification

Documents

Application Documents