Provided is a lubricant base stock, a lubricating oil including the lubricant base stock and a method for improving viscosity temperature performance or viscosity index of an engine or other mechanical component lubricated with the lubricating oil. The lubricant base stock includes one or more liquid crystals represented by the formula:

R1-(A).sub.m-Y(B).sub.nR2

wherein R1 and R2 are the same or different and are a substituted or unsubstituted, alkyl or alkoxy group having from 0 to 24 carbon atoms; A and B are the same or different and are a cycloaliphatic group or aromatic group, provided at least one of A and B is an aromatic group; Y is a covalent bond, CH2-CH2-, CHCH, CC, OCOO, COO, CO, CSO, CSS, CS, O, S, SO, SO2-, CH2O, OCH2O, NO, ONO2, COOH, OH, or CN; and m and n are independently 0, 1, 2 or 3. The lubricant base stock has a kinematic viscosity of 2 cSt to 28 cSt at 40 C., and 1 cSt to 12 cSt at 100 C.

The present invention relates to compositions for use in refrigeration, air-conditioning, and heat pump systems wherein the composition comprises a tetrafluoropropene and at least one other component. The compositions of the present invention are useful in processes for producing cooling or heat, as heat transfer fluids, foam blowing agents, aerosol propellants, and fire suppression and fire extinguishing agents.

The present invention relates to compositions for use in refrigeration, air-conditioning, and heat pump systems wherein the composition comprises a tetrafluoropropene and at least one other component. The compositions of the present invention are useful in processes for producing cooling or heat, as heat transfer fluids, foam blowing agents, aerosol propellants, and fire suppression and fire extinguishing agents.

The present invention provides a refrigerating machine oil including a lubricating base oil and a compound represented by the following formula (A):

##STR00001##

wherein R.sup.a and R.sup.b each independently represent a monovalent hydrocarbon group, R.sup.c represents a divalent hydrocarbon group, X represents a polar group, and Z.sup.a and Z.sup.b each independently represent oxygen atom or sulfur atom.

The present invention provides a refrigerating machine oil including a lubricating base oil and a compound represented by the following formula (A):

##STR00001##

wherein R.sup.a and R.sup.b each independently represent a monovalent hydrocarbon group, R.sup.c represents a divalent hydrocarbon group, X represents a polar group, and Z.sup.a and Z.sup.b each independently represent oxygen atom or sulfur atom.

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).

A method for improving wear control of a steel surface lubricated with a lubricating oil through the generation of thick tribofilms. The method includes: (i) using as the lubricating oil a formulated oil, the formulated oil having a composition comprising at least one lubricating oil base stock as a major component; and at least one lubricating oil additive, as a minor component; and (ii) forming a tribofilm on the steel surface. In time-step tribofilm formation measurements of the lubricating oil by a mini-traction machine (MTM) at constant slide-to-roll ratio (SRR), the saturation traction coefficient (f.sub.s), which correlates to tribofilm thickness on the steel surface, is greater than about 0.11. In the method of this disclosure, elongation of timing chain due to wear of chain link pins is less than about 0.07%, as determined by Ford Chain Wear (FCW) test conducted in accordance with ILSAC GF-6 specification. The lubricating oils are useful in internal combustion engines.

A method for improving wear control of a steel surface lubricated with a lubricating oil through the generation of thick tribofilms. The method includes: (i) using as the lubricating oil a formulated oil, the formulated oil having a composition comprising at least one lubricating oil base stock as a major component; and at least one lubricating oil additive, as a minor component; and (ii) forming a tribofilm on the steel surface. In time-step tribofilm formation measurements of the lubricating oil by a mini-traction machine (MTM) at constant slide-to-roll ratio (SRR), the saturation traction coefficient (f.sub.s), which correlates to tribofilm thickness on the steel surface, is greater than about 0.11. In the method of this disclosure, elongation of timing chain due to wear of chain link pins is less than about 0.07%, as determined by Ford Chain Wear (FCW) test conducted in accordance with ILSAC GF-6 specification. The lubricating oils are useful in internal combustion engines.

A method for improving wear control, while maintaining or improving deposit control and cleanliness, in an engine or other mechanical component lubricated with a lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition including a lubricating oil base stock as a major component, and specific combinations of low soap detergents, dispersants, and/or mixtures thereof, as a minor component. The low soap detergents include alkaline earth metal salicylates, alkaline earth metal sulfonates, or mixtures thereof, all having the same or different total base number (TBN). The total amount of soap delivered by the low soap detergent is less than 0.60 weight percent of the lubricating oil. The dispersants include borated and/or non-borated polyisobutylene succinimide (PIMA) having a basic nitrogen content of 1% or greater. The lubricating oils are useful in internal combustion engines.