A biodegradable compressor oil comprising a biobased hydrocarbon base oil.

A heat pump apparatus is provided in which refrigerant circulates between an indoor unit and an outdoor unit, wherein the refrigerant is a mixed refrigerant of HFO-1123 and an HFC refrigerant other than HFO-1123, the outdoor unit has a cooling capacity (kW) in the range of 2.2 to 9.5 kW, the outer diameter (mm) of a gas pipe between the indoor unit and the outdoor unit and the cooling capacity (kW) of the outdoor unit satisfy the relation (1.00outer diameter (mm) of gas pipe/cooling capacity (kW) of outdoor unit5.77), and the outer diameter (mm) of a liquid pipe between the indoor unit and the outdoor unit and the cooling capacity (kW) of the outdoor unit satisfy the relation (0.67outer diameter (mm) of liquid pipe/cooling capacity (kW) of outdoor unit5.77).

An object of the present invention is to provide a lubricating oil composition having a low viscosity and an extremely high viscosity index as well as an excellent shearing stability. The present invention relates to a lubricating oil composition including the following components (A) to (C): (A) a low-viscosity synthetic oil including a compound containing an ether bond in a molecule thereof and having a kinematic viscosity of less than 10 mm.sup.2/s as measured at 40 C., in which a ratio of the number of oxygen atoms to the number of carbon atoms as constituents of the compound (O/C ratio) and the kinematic viscosity (mm.sup.2/s) of the compound as measured at 40 C. satisfy the following formula (1):
Kinematic Viscosity at 40 C.12[(O/C ratio)30](1); (B) a high-viscosity synthetic oil as a hydrocarbon-based synthetic oil having a kinematic viscosity of 40 mm.sup.2/s or more as measured at 100 C. which includes at least one compound selected from the group consisting of an -olefin oligomer or a hydrogenated product of the -olefin oligomer, and an ethylene-propylene co-oligomer; and (C) a polymethacrylate having a weight-average molecular weight of 50,000 or less.

A lubricant contains alcohol initiated propylene oxide homopolymer, an oil soluble polyalkylene glycol other than the alcohol initiated propylene oxide homopolymer, and a calcium salt of dinonylnaphthalene sulphonate where the lubricant is further characterized by containing less than ten weight-percent of polyol esters based on total lubricant weight is useful as a lubricant for compressors.

A lubricating composition comprises an amide and at least one additive. The amide is the reaction product of a secondary, branched amine and a carboxylic acid. The carboxylic acid may be a monocarboxylic acid or a dicarboxylic acid, including dimer acid. The amide is hydrolytically stable, and may be used to increase the hydrolytic stability of the lubricant composition. Alternatively, the amide may be used to increase the additive solubility or detergency of the lubricant composition.

A lubricant additive concentrate containing 30 to 80 mass % oil of lubricating viscosity and from 20 to 70 mass % of additive; wherein from 30 to 90 mass % of the additive is (i) hybrid overbased colloidal detergent derived from sulfonate surfactant and hydroxybenzoate surfactant; and (ii) polyalkenyl succinimide dispersant derived from a polyalkene having a number average molecular weight (M.sub.n) of from 1300 to 2500 daltons, and wherein the mass ratio of polyalkenyl succinimide dispersant (ii) to hybrid overbased colloidal detergent (i) in the lubricant additive is from 25:1 to 1:1.

A lubricating formulation prepared from a blend of components comprised of 35-55% of a first base oil; 30-50% of a second base oil; 0.5-5% of a hydrophobic fumed silica; and 1-10% of a hydrophilic fumed silica, wherein the hydrophobic fumed silica and the hydrophilic fumed silica are introduced during formulation so that the hydrophobic famed silica and the hydrophilic fumed silica are pulverized, discharged and dissolved under a surface the blend during formulation.

A lithium salt thickener that enhances thermal stability at high temperature and operability at low temperature, and a grease composition including the same, is provided.

To provide a composition for a heat cycle system, which comprises a working fluid for heat cycle which has a low global warming potential and high stability, and which can replace R410A, and a heat cycle system employing the composition.

A composition for a heat cycle system, which comprises a working fluid for heat cycle containing 1,2-difluoroethylene, and a stabilizer for preventing deterioration of the working fluid for heat cycle, such as an oxidation resistance-improving agent, a heat resistance-improving agent or a metal deactivator, and a heat cycle system employing the composition for a heat cycle system.

To provide a composition for a heat cycle system having favorable lubricating properties and comprising a working fluid for heat cycle which has a low global warming potential and which can replace R410A and a heat cycle system employing the composition.

A composition for a heat cycle system comprising a working fluid for heat cycle containing 1,2-difluoroethylene, and a refrigerant oil such as an oxygen-containing synthetic oil (such as an ester refrigerant oil or an ether refrigerant oil) or a hydrocarbon refrigerant oil, and a heat cycle system employing the composition for a heat cycle system.