A lubricant made by a method of modifying fluid suspended metal sulfide particles that does not require use of hazardous additives. The base oil is derived from a proprietary ester lubricant. The formulation process includes a centrifugation step to remove non-colloidal metal sulfide particles. These non-colloidal particles may be collected and turned into colloidal particles for use in future batches of lubricant.

A lubricant made by a method of modifying fluid suspended metal sulfide particles that does not require use of hazardous additives. The base oil is derived from a proprietary ester lubricant. The formulation process includes a centrifugation step to remove non-colloidal metal sulfide particles. These non-colloidal particles may be collected and turned into colloidal particles for use in future batches of lubricant.

The present invention provides a biodegradable lubricating oil composition containing 50% by mass or more of a synthetic ester base oil (A), 0.1 to 3% by mass of an amine-based antioxidant (B1), 0.1 to 3% by mass of a phenol-based antioxidant (B2), and 0.01 to 2% by mass of a sulfur-phosphorus-based extreme-pressure agent (C), wherein the transmittance at 3,0051 cm.sup.1 of a 0.1 mm-thick liquid film of the composition, as measured through IR absorptiometry, is 50% or more.

There are provided a composition for a heat cycle system containing a working medium for heat cycle that has a low global warming potential and high stability, which can be used as a substitute for HFC-134a and HFC-245fa, and a heat cycle system using this composition. The composition for a heat cycle system contains: a working medium for heat cycle containing 1-chloro-2,3,3,3-tetrafluoropropene; and a stabilizer suppressing deterioration of the working medium for heat cycle such as an oxidation resistance improver, a heat resistance improver, or a metal deactivator, and the heat cycle system uses this composition for a heat cycle system.

Grease wear test device includes a body in a form of a collar having an outer surface, a first side and an opposing second side, which are open to form a hollow, open channel through the body, which has a center axis, into which opposing vee blocks can be inserted; and perpendicular to the center axis, a pair of opposing holes through and open to the outer surface of the body and the cylindrical inside wall, through which a cylindrical test journal (falex pin) can be inserted for contact in general with opposing vee-shaped channels of the inserted, opposing vee blocks, and for rotation during testing. The device can be used to modify a falex pin and vee block device, to receive and contain a small sample of grease or another organic paste product for testing such as a modified version of an ASTM D2670 test method for measuring wear properties of fluid lubricants (falex pin and vee block method).

Grease wear test device includes a body in a form of a collar having an outer surface, a first side and an opposing second side, which are open to form a hollow, open channel through the body, which has a center axis, into which opposing vee blocks can be inserted; and perpendicular to the center axis, a pair of opposing holes through and open to the outer surface of the body and the cylindrical inside wall, through which a cylindrical test journal (falex pin) can be inserted for contact in general with opposing vee-shaped channels of the inserted, opposing vee blocks, and for rotation during testing. The device can be used to modify a falex pin and vee block device, to receive and contain a small sample of grease or another organic paste product for testing such as a modified version of an ASTM D2670 test method for measuring wear properties of fluid lubricants (falex pin and vee block method).

The present invention provides a working fluid composition for a refrigerating machine containing: a refrigerating machine oil containing, as a base oil, a mixed ester of (A) a complex ester synthesized from a polyhydric alcohol such as neopentyl glycol, a polybasic acid having 6 to 12 carbon atoms, a monohydric alcohol having 4 to 18 carbon atoms and the like, and (B) a polyol ester synthesized from a polyhydric alcohol such as neopentyl glycol and a monocarboxylic fatty acid having 4 to 18 carbon atoms, in a mass ratio of (A) the complex ester/(B) the polyol ester of 5/95 to 95/5; and a refrigerant such as carbon dioxide.

The present invention provides a working fluid composition for a refrigerating machine containing: a refrigerating machine oil containing, as a base oil, a mixed ester of (A) a complex ester synthesized from a polyhydric alcohol such as neopentyl glycol, a polybasic acid having 6 to 12 carbon atoms, a monohydric alcohol having 4 to 18 carbon atoms and the like, and (B) a polyol ester synthesized from a polyhydric alcohol such as neopentyl glycol and a monocarboxylic fatty acid having 4 to 18 carbon atoms, in a mass ratio of (A) the complex ester/(B) the polyol ester of 5/95 to 95/5; and a refrigerant such as carbon dioxide.

Provided is a lubricating oil composition for a shock absorber, which realizes excellent riding comfort in low-temperature and high-temperature environments and can suppress worsening of riding comfort with time, which is caused by evaporation and shearing of the lubricating oil. The lubricating oil composition for a shock absorber contains (A) a base oil having a pour point of lower than 40 C. and a kinematic viscosity at 80 C. of from 2.0 to 2.7 mm.sup.2/s, (B-1) from 1 to 15% by mass of a polymethacrylate having a weight-average molecular weight of from 10,000 to less than 100,000, and (B-2) from 0.1 to 5% by mass of a polymethacrylate having a weight-average molecular weight of from 100,000 to 200,000.

Provided is a lubricating oil composition for a shock absorber, which realizes excellent riding comfort in low-temperature and high-temperature environments and can suppress worsening of riding comfort with time, which is caused by evaporation and shearing of the lubricating oil. The lubricating oil composition for a shock absorber contains (A) a base oil having a pour point of lower than 40 C. and a kinematic viscosity at 80 C. of from 2.0 to 2.7 mm.sup.2/s, (B-1) from 1 to 15% by mass of a polymethacrylate having a weight-average molecular weight of from 10,000 to less than 100,000, and (B-2) from 0.1 to 5% by mass of a polymethacrylate having a weight-average molecular weight of from 100,000 to 200,000.