A refrigerant compressor comprises an electric component; and a compression component which is driven by the electric component and compresses a refrigerant. At least one of slide members included in the compression component is made of an iron-based material. An oxide coating film (150) is provided on a slide surface of the iron-based material, the oxide coating film including a first portion (151), a second portion (152), and/or a third portion (153). The first portion (151) contains at least fine crystals (155). The second portion (152) contains columnar grains (156). The third portion (153) contains layered grains (157).

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.

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.

A lubricating composition comprising a base oil of lubricating viscosity and one or more lubricant additives, wherein the base oil comprises or consists of a base stock which comprises or consists of at least one isoprenoid compound comprising: (i) one or two oxygen-containing moieties independently selected from ether and ester moieties; (ii) a first acyclic isoprenoid moiety containing 1 to 5 isoprenyl units; and (iii) optionally, a second acyclic isoprenoid moiety containing 1 to 5 isoprenyl units with the proviso that at least one isoprenoid moiety contains 3 to 5 isoprenyl units where the isoprenoid compound contains a single ether moiety.

A lubricating composition comprising a base oil of lubricating viscosity and one or more lubricant additives, wherein the base oil comprises or consists of a base stock which comprises or consists of at least one isoprenoid compound comprising: (i) one or two oxygen-containing moieties independently selected from ether and ester moieties; (ii) a first acyclic isoprenoid moiety containing 1 to 5 isoprenyl units; and (iii) optionally, a second acyclic isoprenoid moiety containing 1 to 5 isoprenyl units with the proviso that at least one isoprenoid moiety contains 3 to 5 isoprenyl units where the isoprenoid compound contains a single ether moiety.

A method for preventing or reducing engine knock or pre-ignition in a high compression spark ignition engine lubricated with a lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition that contains (i) a lubricating oil base stock comprising at least one ester including at least one group selected from the group consisting of Formula (1), Formula (2), and Formula (3): ##STR00001##
The lubricating oils of this disclosure are useful as passenger vehicle engine oil (PVEO) products.

A method for preventing or reducing engine knock or pre-ignition in a high compression spark ignition engine lubricated with a lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition that contains (i) a lubricating oil base stock comprising at least one ester including at least one group selected from the group consisting of Formula (1), Formula (2), and Formula (3): ##STR00001##
The lubricating oils of this disclosure are useful as passenger vehicle engine oil (PVEO) products.

Provided herein are estolide compositions having high oxidative stability, said compositions comprising at least one compound of formula: ##STR00001##
in which n is an integer equal to or greater than 0; m is an integer equal to or greater than 1; R.sub.1, independently for each occurrence, is selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; R.sub.2 is selected from hydrogen and optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; and R.sub.3 and R.sub.4, independently for each occurrence, are selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched. Also provided herein are uses for the compositions and methods of preparing the same.

Provided herein are estolide compositions having high oxidative stability, said compositions comprising at least one compound of formula: ##STR00001##
in which n is an integer equal to or greater than 0; m is an integer equal to or greater than 1; R.sub.1, independently for each occurrence, is selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; R.sub.2 is selected from hydrogen and optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; and R.sub.3 and R.sub.4, independently for each occurrence, are selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched. Also provided herein are uses for the compositions and methods of preparing the same.

A viscosity index improver containing, in non-ester diluent oil, one or more hydrogenated, functionalized linear block copolymers having at least one block derived from monoalkenyl arene covalently linked to at least one block derived from diene in an amount that is greater than the critical overlap concentration (c.sub.h*), in mass %, for the linear block copolymers in the diluent oil; and an amount of ester base stock.