Grease composition and use of grease composition
AssigneeIdemitsu Kosan Co., Ltd.
InventorGo Watanabe
Life of this patent
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Abstract
Provided is a grease composition which contains (A) a mixed base oil containing (A1) a low-viscosity base oil having a kinematic viscosity at 40° C. of 10 to 50 mm2/s and (A2) a high-viscosity base oil having a kinematic viscosity at 40° C. of 200 to 700 mm2/s, (B) a lithium-based thickener and (C) a polymer having a kinematic viscosity at 100° C. of 1,000 to 100,000 mm2/s, and has an apparent viscosity at −10° C., as measured according to JIS K2220:2013 and at a shear rate of 10 s−1, of 50 to 250 mPa·s. The grease composition is excellent in pumpability and is also excellent in wear resistance under poor lubrication conditions.
Claims19
A method, comprising employing a grease composition in a slewing mechanism of a construction machine equipped with a centralized lubrication system or a mining machine equipped with a centralized lubrication system, wherein the grease composition comprises:
- (A) a mixed base oil comprising (A1) a low-viscosity mineral oil having a kinematic viscosity at 40° C. in a range of from 10 to 50 mm2/s and (A2) a high-viscosity mineral oil having a kinematic viscosity at 40° C. in a range of from 200 to 700 mm2/s;
- (B) a lithium-based thickener comprising a simple lithium soap;
- and
- (C) a polymer having a kinematic viscosity at 100° C. in a range of from 1,000 to 100,000 mm2/s;
- (D) a organic zinc compound;
- and
- (E) an extreme pressure agent,
- wherein the grease composition has an apparent viscosity in a range of from 50 to 250 mPa·s at −10° C., as measured according to JIS K2220:2013 and at a shear rate of 10 s−1,
- wherein the low-viscosity mineral oil (A1) and the high-viscosity mineral oil (A2) are present in a (A1)/(A2) content ratio in a range of from 1/5 to 10/1, and
- wherein the polymer (C) is chemically distinct from the mixed base oil (A).
A method of making a lubricant grease composition, the method comprising:
- combining:
- (A) a mixed base oil comprising (A1) a low-viscosity mineral oil having a kinematic viscosity at 40° C. in a range of from 10 to 50 mm2/s and (A2) a high-viscosity mineral oil having a kinematic viscosity at 40° C. in a range of from 200 to 700 mm2/s ;
- (B) a lithium-based thickener comprising a simple lithium soap;
- and (C) a polybutene having a kinematic viscosity at 100° C. in a range of from 1,000 to 100,000 mm2/s;
- (D) a organic zinc compound;
- and (E) an extreme pressure agent, wherein the low-viscosity mineral oil (A1) and the high-viscosity mineral oil (A2) are present in a (A1)/(A2) content ratio in a range of from 1/5 to 10/1, wherein the grease composition has an apparent viscosity in a range of from 50 to 250 mPa-s at −10° C., as measured according to JIS K2220:2013 and at a shear rate of 10 s−, and wherein the polymer (C) is chemically distinct from the mixed base oil (A), to form the grease composition.
Dependencies are inferred from the claim text.