The present invention provides a lubricating oil composition for automatic transmissions which comprises: 55 to 85 mass % of a Fischer-Tropsch synthetic oil with a kinematic viscosity at 100 C. of 2 to 4 mm2/s as a low-viscosity base oil; 1 to 10 mass % of an olefin copolymer 5 with a kinematic viscosity at 100 C. of 150 to 1,000 mm2/s as a high-viscosity base oil; and a polymethacrylate with a weight-average molecular weight of 10,000 to 50,000. This lubricating oil composition is such that the viscosity index of the composition is not 10 less than 190, the Brookfield viscosity is not more than 6,000 mPa.Math.s at low temperature (40 C.), the kinematic viscosity at 100 C. is 6 to 7 mm2/s, and the rate of reduction of the kinematic viscosity after a KRL shear stability test (60 C., 20 hr) is kept to within not more 15 than 3%.

A comb polymer can be used for reducing a Noack evaporation loss of a lubricant composition, especially of an engine oil composition. Application of the comb polymer to the lubricant composition can bring about the desired reduction. The comb polymer can include specified amounts of macromonomer and alkyl acrylates. Resulting lubricant compositions can include the comb polymer.

Selected comb polymers include specified amounts of macromonomer and imide functionalization. Further, a method is useful for the preparation of such comb polymers. Lubricant compositions including such comb polymers are useful for reducing wear and fuel consumption of lubricant compositions, especially of engine oil (EO) compositions.

To provide a lubricating oil composition achieving both of high traction coefficient and excellent low temperature fluidity at a higher level and having a high flash point, which contains a naphthene-based synthetic oil (a) having a flash point of 140 C. or higher, and an ester (b) having 5 to 32 carbon atoms and having a branched chain, wherein the content of the naphthene-based synthetic oil (a) based on the total amount of the composition is 35% by mass or more and less than 80% by mass, a method for producing the lubricating oil composition, and a continuously variable transmission using the lubricating oil composition.

This disclosure relates to a heat transfer fluid having at least one first ester that is partially esterified, and at least one second ester that is fully esterified. The heat transfer fluid has a flash point from about 125 C. to about 225 C. as determined by ASTM D-93, and a kinematic viscosity (KV.sub.100) from about 1 to about 5 at 100 C. as determined by ASTM D-445. The at least one first ester and the at least one second ester are present in an amount such that, as the flash point and thermal conductivity of the heat transfer fluid are increased, the kinematic viscosity (KV.sub.100) of the heat transfer fluid is decreased or essentially maintained. This disclosure also relates to a method for increasing flash point and thermal conductivity, while decreasing or essentially maintaining viscosity, of a heat transfer fluid by using the heat transfer fluid.

An object of the present invention is to provide an ester-based lubricating base oil for a fluid bearing that has excellent hydrolysis resistance and low-temperature fluidity, a high viscosity index, and good evaporation resistance. The present invention relates to a lubricating base oil for a fluid bearing comprising a compound represented by general formula (1):

##STR00001##

wherein R.sup.1 represents a linear C.sub.7-C.sub.13 alkyl group, and a compound represented by general formula (2):

##STR00002##

wherein R.sup.2 represents a linear C.sub.7-C.sub.13 alkyl group; and relates to a base oil composition comprising the base oil.

Provided is a method for improving oxidation resistance and deposit resistance of a lubricating oil for use in lubricating a mechanical component. The method includes the step of providing the lubricating oil to the mechanical component and measuring the improved oxidation and deposit resistance. The lubricating oil includes a lubricating oil base stock at from 0 to 80 wt %, at least one branched isoparaffin having a mole % of epsilon carbon as measured by C.sub.13 NMR of less than or equal to 10% at from 20 to 80 wt %, at least one viscosity modifier at from 5 to 20 wt %, and one or more other lubricating oil additives. The oxidation resistance in the CEC L-109 oxidation resistance test is improved to greater than 310 hours to achieve a 100% viscosity increase and the deposit resistance in the TEOST 33C is improve to total deposits of less than 45 mg as compared to oxidation resistance and deposit resistance achieved using a lubricating oil not containing the at least one branched isoparaffin.

A comb polymer can be used for reducing a Noack evaporation loss of a lubricant composition, especially of an engine oil composition. Application of the comb polymer to the lubricant composition can bring about the desired reduction. The comb polymer can include specified amounts of macromonomer and alkyl acrylates. Resulting lubricant compositions can include the comb polymer.

A lubricant composition includes a perfluoropolyether as a base oil, a fluororesin as a thickener, and a polyol ester, a urea grease and a zinc dialkyldithiophosphate as additives, wherein a mass ratio of content of the perfluoropolyether to total content of the polyol ester and the urea grease ranges from 78/22 to 95/5, a mass ratio of content of the perfluoropolyether to content of the polyol ester ranges from 90/10 to 96.5/3.5, a mass ratio of content of the polyol ester to content of the urea grease ranges from 40/60 to 65/35, content of the fluororesin ranges from 15 mass % to 24 mass % based on a total amount of the lubricant composition, and content of the zinc dialkyldithiophosphate ranges from 0.5 mass % to 4 mass % based on the total amount of the lubricant composition.

Compositions, methods, systems, and applications herein are directed to lubricant blends that balance solubility and viscosity of a refrigerant, where in some cases the lubricant blends herein help reduce solubility of a refrigerant. A lubricant blend includes a mixture of two or more different types of lubricants to reduce refrigerant solubility.