Refrigerator oil and working fluid composition for refrigerator

Abstract

A refrigerating machine oil having a flash point of 130°C or lower and a residual carbon content of 0.02 mass % or more in 10% residual oil.

Description

Technical Field

[0001] The present invention relates to refrigeration oil and a working fluid composition for refrigeration machines. Background Art

[0002] In refrigerators, it is becoming increasingly urgent to replace refrigerants having a high global warming potential (GWP) with low GWP refrigerants, for example, less than 150. Examples of low GWP refrigerants include carbon dioxide (R744) refrigerants and hydrocarbon refrigerants.

[0003] On the other hand, energy conservation is also required for refrigerators. Generally, the lower the viscosity of refrigerator oil, the less stirring resistance and friction of sliding parts can be reduced. Therefore, the lower viscosity of refrigerator oil is related to energy conservation of refrigerators. For example, Patent Document 1 discloses refrigerator oils with a viscosity of VG3 or more and VG8 or less.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2006 / 062245 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] As one of the solutions to reduce the viscosity of refrigeration oil, increasing the content of light components in refrigeration oil is considered. Refrigeration oil containing many light components can also be called refrigeration oil with a low flash point. However, if the flash point of refrigeration oil becomes lower (the content of light components becomes higher), it becomes difficult to maintain the oil film in the sliding part, so there is a concern that the wear resistance will be reduced, for example.

[0009] Therefore, an object of one aspect of the present invention is to provide a refrigerating machine oil having a low flash point but excellent wear resistance.

[0010] Solutions for solving problems

[0011] According to the research conducted by the present inventors, it was found that even when the flash point of a refrigeration oil is low (for example, 130° C. or less), excellent wear resistance can be obtained if the residual carbon content of 10% residual oil of the refrigeration oil is within a predetermined range.

[0012] One aspect of the present invention is a refrigerating machine oil having a flash point of 130° C. or lower and a residual carbon content of 0.02 mass % or more in 10% residual oil.

[0013] The refrigeration oil may contain a kinematic viscosity of 6 mm at 40°C. 2 / s or less low viscosity hydrocarbon oil, and a kinematic viscosity of 200mm at 40°C 2 / s or more high viscosity hydrocarbon oil. Based on the total amount of refrigeration oil, the content of low viscosity hydrocarbon oil can be 85% by mass or more. Based on the total amount of refrigeration oil, the content of high viscosity hydrocarbon oil can be 10% by mass or less. The 90% distillation temperature of refrigeration oil can be 270°C or less.

[0014] Another aspect of the present invention is a working fluid composition for a refrigerator, comprising the above-mentioned refrigerator oil and a refrigerant. The refrigerant may contain a hydrocarbon.

[0015] Effects of the Invention

[0016] According to one aspect of the present invention, it is possible to provide a refrigerating machine oil having a low flash point but excellent wear resistance. DETAILED DESCRIPTION

[0017] Embodiments of the present invention will be described in detail below. One embodiment of the present invention is a refrigerating machine oil having a flash point of 130° C. or less and a residual carbon content of 0.02 mass % or more in 10% residual oil.

[0018] The flash point of the refrigerating machine oil may be, for example, 70° C. or higher, 80° C. or higher, 90° C. or higher, 100° C. or higher, or 110° C. or higher, and from the viewpoint of further reducing the viscosity of the refrigerating machine oil, may be 125° C. or lower or 120° C. or lower. The flash point in this specification refers to the flash point measured according to the Cleveland open (COC) method described in JIS K2265-4:2007.

[0019] The residual carbon content of 10% residual oil of refrigeration oil is preferably 0.05% by mass or more, 0.08% by mass or more, or 0.1% by mass or more, from the viewpoint of further improving wear resistance, and can be, for example, 0.6% by mass or less, 0.5% by mass or less, or 0.4% by mass or less. The residual carbon content in this specification refers to the residual carbon content measured by the micro method according to JIS K2270-2: 2009. The residual carbon content of 10% residual oil in this specification refers to the residual carbon content measured by the same method for the residual oil after distillation of refrigeration oil and removal of distillate oil with a volume fraction of up to 90%.

[0020] The kinematic viscosity of the refrigeration oil at 40°C may be, for example, 1 mm 2 / s or more, 1.5mm 2 / s or more, or 2mm 2 / s or more, can be 6mm 2 / s or less, 5mm 2 / s or less, 4.5mm 2 / s or less, 4mm2 / s or less, 3.5mm 2 / s or less, or 3mm 2 The kinematic viscosity in this specification means the kinematic viscosity measured according to JIS K2283:2000.

[0021] The kinematic viscosity of the refrigeration oil at 100°C may be, for example, 0.5 mm 2 / s or more, 0.7mm 2 / s or more, or 1mm 2 / s or more, can be 2mm 2 / s or less, 1.5mm 2 / s or less, 1.4mm 2 / s or less, 1.3mm 2 / s or less, 1.2mm 2 / s or less, or 1.1mm 2 / s or less.

[0022] The density of refrigeration oil can be, for example, 0.78 g / cm 3 Above, 0.79g / cm 3 Above, or 0.80g / cm 3 Above, it can be 0.85g / cm 3 Below, 0.84g / cm 3 Below, or 0.83g / cm 3 The density in this specification means the density at 15° C. measured according to the “vibration method” described in JIS K2249-1:2011.

[0023] The pour point of the refrigerating machine oil may be, for example, -10°C or lower, -20°C or lower, -30°C or lower, or -40°C or lower, or may be -60°C or higher. The pour point in this specification means a pour point measured in accordance with JIS K2269:1987.

[0024] The content of hydrocarbons having 12 to 16 carbon atoms (C12-16 component amount) in refrigeration oil or in hydrocarbon oil contained in refrigeration oil can be preferably 80 mass % or more, 85 mass % or more, or 90 mass % or more, and can be 97 mass % or less, 96 mass % or less, or 95 mass % or less, based on the total amount of hydrocarbon oil, from the viewpoint of further improving wear resistance.

[0025] The content of hydrocarbons having 13 to 18 carbon atoms (C13-18 component amount) in refrigeration oil or in hydrocarbon oil contained in refrigeration oil can be preferably 80 mass % or more, 85 mass % or more, or 90 mass % or more, and can be 99 mass % or less, 98 mass % or less, or 97 mass % or less, based on the total amount of hydrocarbon oil, from the viewpoint of further improving wear resistance.

[0026] The content of normal alkanes in the refrigerating machine oil or in the hydrocarbon oil contained in the refrigerating machine oil may be preferably 0.5% by mass or more, 2% by mass or more, 5% by mass or more, 8% by mass or more, or 9% by mass or more, based on the total amount of hydrocarbon oil, from the viewpoint of further improving wear resistance, and may be 50% by mass or less, 30% by mass or less, or 25% by mass, and from the viewpoint of low-temperature fluidity, may be 40% by mass or less, 30% by mass or less, 20% by mass or less, or 15% by mass or less. In addition, from the viewpoint of further reducing the friction coefficient, the content of normal alkanes may be 5% by mass or more, 10% by mass or more, 15% by mass or more, or 20% by mass or more.

[0027] The content of paraffins in refrigeration oil or in hydrocarbon oil contained in refrigeration oil may preferably be 30% by mass or more, 40% by mass or more, 50% by mass or more, 55% by mass or more, or 60% by mass or more, and may be 100% by mass or less, 90% by mass or less, or 80% by mass or less, based on the total amount of hydrocarbon oil, from the viewpoint of further reducing the friction coefficient.

[0028] The content of 1- to 6-ring cycloalkanes (hereinafter referred to as "cycloalkanes") in refrigeration oil or in hydrocarbon oil contained in refrigeration oil may be preferably 70% by mass or less, 60% by mass or less, 50% by mass or less, 45% by mass or less, or 40% by mass or less, and may be 0% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, or 35% by mass or more, based on the total amount of hydrocarbon oil, from the viewpoint of further reducing the friction coefficient.

[0029] The ratio of the aforementioned chain alkane to the aforementioned cycloalkane (chain alkane / cycloalkane) is preferably 0.3 or more, 0.6 or more, 1.0 or more, 1.2 or more, 1.4 or more, 1.5 or more or 1.8 or more, and is preferably 100 or less, 50 or less, 10 or less, 5 or less or 4 or less, from the viewpoint of further reducing the friction coefficient.

[0030] The aromatic component in the refrigerating machine oil or the hydrocarbon oil contained in the refrigerating machine oil may preferably be 10% by mass or less, 5% by mass or less, 3% by mass or less, or 1% by mass or less from the viewpoint of further reducing the friction coefficient.

[0031] In this specification, the content of hydrocarbons with carbon numbers of 12 to 16, hydrocarbons with carbon numbers of 13 to 18, normal alkanes, chain alkanes, cycloalkanes and aromatic hydrocarbon oils in the above-mentioned refrigeration oil or in the hydrocarbon oil contained in the refrigeration oil is obtained as follows: for the analysis object sample, silica gel chromatography is used to fractionate into saturated hydrocarbon oils and aromatic hydrocarbon oils, and for each, hydrocarbon type analysis based on GC-TOFMS method based on a combination of gas chromatography and mass spectrometry based on FI ionization method is used to obtain. An example of analysis conditions is shown below. According to the above-mentioned fractionation based on silica gel chromatography, the content of saturated hydrocarbon oil and aromatic hydrocarbon oil can also be obtained.

[0032] (Gas chromatography conditions)

[0033] Column: ZB-1MS manufactured by Phenomenex

[0034] Injection temperature: 350℃

[0035] Heating conditions: 50℃~350℃ (heating rate: 5℃ / min)

[0036] Carrier gas: Helium

[0037] Injection method: split flow

[0038] Sample injection volume: 1 μL (10% toluene solution)

[0039] (MS conditions)

[0040] Counter electrode voltage: -10kV

[0041] Ionization method: FI (field ionization)

[0042] Ion source temperature: room temperature

[0043] Mass number measurement range: m / z 35~500

[0044] In the mass spectrum obtained by GC-TOFMS analysis, the type of each carbon number (C n H 2n+z , where n represents an integer and z represents an even number of -18 to 2) is the ratio of different ionic strengths. In this specification, the content (mass %) of each component can be calculated as being substantially the same as the ionic strength % of each component. It should be noted that, when the aromatic hydrocarbon component of the sample according to silica gel chromatographic fractionation is less than 1 mass %, the chromatographic fractionation can be omitted and the hydrocarbon type analysis based on the GC-TOFMS method can be performed. In this case, all are regarded as saturated hydrocarbon components and the content of each component is calculated.

[0045] The refrigerating machine oil may have the distillation properties described below. Hereinafter, the distillation properties of the refrigerating machine oil and the hydrocarbon oil contained therein are all measured according to the normal pressure method described in JIS K2254:2018.

[0046] The initial boiling point (IBP) of the refrigeration oil may be preferably 140°C or higher, 170°C or higher, 190°C or higher, 200°C or higher, 210°C or higher, 220°C or higher, 230°C or higher, or 240°C or higher, and may be 260°C or lower, 255°C or lower, or 250°C or lower, from the viewpoint of further improving the wear resistance.

[0047] The 10% distillation temperature (T10) of the refrigeration oil is preferably 200°C or higher, 210°C or higher, 220°C or higher, 230°C or higher, or 240°C or higher, and may be 260°C or lower, 255°C or lower, or 250°C or lower, from the viewpoint of further improving wear resistance.

[0048] The 50% distillation temperature (T50) of the refrigeration oil is preferably 210°C or higher, 220°C or higher, 230°C or higher, 240°C or higher, or 245°C or higher, and may be 265°C or lower, 260°C or lower, 255°C or lower, or 250°C or lower, from the viewpoint of further improving wear resistance.

[0049] The 90% distillation temperature (T90) of the refrigeration oil is preferably 220°C or higher, 230°C or higher, 240°C or higher, 245°C or higher, or 250°C or higher, and may be 270°C or lower, 267°C or lower, 266°C or lower, 265°C or lower, 264°C or lower, 263°C or lower, 262°C or lower, or 261°C or lower, from the viewpoint of further improving the wear resistance.

[0050] The final boiling point (EP) of the refrigeration oil is preferably 250°C or higher, 260°C or higher, 270°C or higher, 275°C or higher, or 280°C or higher, and may be 320°C or lower, 310°C or lower, 300°C or lower, 295°C or lower, or 290°C or lower, from the viewpoint of further improving the wear resistance.

[0051] The difference between T90 and T10 of the refrigeration oil (T90-T10) is preferably 5°C or more, 6°C or more, 7°C or more, 8°C or more, 9°C or more, or 10°C or more, and may be 40°C or less, 30°C or less, 20°C or less, or 15°C or less, from the viewpoint of further improving the wear resistance.

[0052] The total distillate of the refrigeration oil can be, for example, 90% by volume or more, 93% by volume or more, or 95% by volume or more, or 99% by volume or less. The residual oil content of the refrigeration oil can be, for example, 1% by volume or more, or 10% by volume or less, 7% by volume or less, or 5% by volume or less. The loss of the refrigeration oil can be, for example, 1% by volume or less, 0.5% by volume or less, or 0.1% by volume or less, or 0% by volume.

[0053] The refrigeration oil described above contains hydrocarbon oil, for example. As hydrocarbon oil, for example, mineral oil hydrocarbon oil, synthetic hydrocarbon oil and their mixed oil can be cited. As mineral oil hydrocarbon oil, it can be cited: using crude oil or its distillation residue as a raw material, appropriately combining the usual petroleum refining treatment (solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrofining, sulfuric acid cleaning, clay treatment, distillation, etc.) and refined paraffinic or cycloparaffinic refined mineral oil. As synthetic hydrocarbon oil, for example, poly α-olefins or their hydrogenated products, isoparaffins, alkylbenzenes, alkylnaphthalenes, etc. can be cited. These hydrocarbon oils can be used alone or in combination of two or more.

[0054] From the viewpoint of further improving the wear resistance, the refrigerating machine oil preferably contains a refrigerating machine oil having a kinematic viscosity of 6 mm at 40°C. 2 / s or less low viscosity hydrocarbon oil and kinematic viscosity at 40°C of 200mm 2 / s or more high viscosity hydrocarbon oil is used as hydrocarbon oil.

[0055] The kinematic viscosity of a low-viscosity hydrocarbon oil at 40° C. may be, for example, 1 mm 2 / s or more, 1.5mm 2 / s or more, or 2mm 2 / s or more, can be 5mm 2 / s or less, 4.5mm 2 / s or less, 4mm 2 / s or less, 3.5mm 2 / s or less, or 3mm 2 / s or less.

[0056] The kinematic viscosity of the low-viscosity hydrocarbon oil at 100° C. may be, for example, 0.5 mm 2 / s or more, 0.7mm 2 / s or more, or 1mm 2 / s or more, can be 2mm 2 / s or less, 1.5mm 2 / s or less, 1.4mm 2 / s or less, 1.3mm 2 / s or less, 1.2mm 2 / s or less, or 1.1mm 2 / s or less.

[0057] The density of low viscosity hydrocarbon oil can be, for example, 0.78 g / cm 3 Above, 0.79g / cm 3 Above, 0.80g / cm 3 Above, 0.81g / cm 3 Above, or 0.82g / cm 3 Above, it can be 0.84g / cm 3 Below, 0.83g / cm 3 Below, 0.82g / cm 3 Below, or 0.81g / cm 3 the following.

[0058] The flash point of the low-viscosity hydrocarbon oil may be, for example, 30°C or higher, 60°C or higher, 90°C or higher, 100°C or higher, or 110°C or higher. From the viewpoint of further lowering the viscosity of the refrigeration oil, it may be 130°C or lower, 125°C or lower, or 120°C or lower.

[0059] The pour point of the low-viscosity hydrocarbon oil may be, for example, -10°C or lower, -20°C or lower, -30°C or lower, or -40°C or lower, and may be -60°C or higher.

[0060] The 90% distillation temperature (T90) of the low-viscosity hydrocarbon oil may be preferably 270°C or lower, 267°C or lower, 266°C or lower, 265°C or lower, 264°C or lower, 263°C or lower, 262°C or lower, or 261°C or lower, from the viewpoint of further improving wear resistance, and may be, for example, 220°C or higher, 230°C or higher, 240°C or higher, 245°C or higher, or 250°C or higher.

[0061] The initial boiling point (IBP) of the low-viscosity hydrocarbon oil may be preferably 140°C or higher, 170°C or higher, 190°C or higher, 200°C or higher, 210°C or higher, 220°C or higher, 230°C or higher, or 240°C or higher, and may be 260°C or lower, 255°C or lower, or 250°C or lower, from the viewpoint of further improving wear resistance.

[0062] The 10% distillation temperature (T10) of the low-viscosity hydrocarbon oil may preferably be 200°C or higher, 210°C or higher, 220°C or higher, 230°C or higher, or 240°C or higher, and may be 260°C or lower, 255°C or lower, or 250°C or lower, from the viewpoint of further improving wear resistance.

[0063] The 50% distillation temperature (T50) of the low-viscosity hydrocarbon oil may preferably be 210°C or higher, 220°C or higher, 230°C or higher, 240°C or higher, or 245°C or higher, and may be 265°C or lower, 260°C or lower, 255°C or lower, or 250°C or lower, from the viewpoint of further improving wear resistance.

[0064] The end boiling point (EP) of the low-viscosity hydrocarbon oil may be preferably 250°C or higher, 260°C or higher, 270°C or higher, 275°C or higher, or 280°C or higher, and may be 320°C or lower, 310°C or lower, 300°C or lower, 295°C or lower, or 290°C or lower, from the viewpoint of further improving wear resistance.

[0065] The difference between T90 and T10 (T90-T10) of the low-viscosity hydrocarbon oil may preferably be 5°C or more, 6°C or more, 7°C or more, 8°C or more, 9°C or more, or 10°C or more, and may be 40°C or less, 30°C or less, 20°C or less, or 15°C or less, from the viewpoint of further improving wear resistance.

[0066] The total distillate of the low-viscosity hydrocarbon oil may be, for example, 95% by volume or more, 96% by volume or more, 97% by volume or more, 98% by volume or more, or 99% by volume or more, or 99.9% by volume or less. The residual oil content of the low-viscosity hydrocarbon oil may be, for example, 0.1% by volume or more, or 6% by volume or less, 4% by volume or less, 3% by volume or less, 2% by volume or less, or 1% by volume or less. The loss of the low-viscosity hydrocarbon oil may be, for example, 1% by volume or less, 0.5% by volume or less, or 0.1% by volume or less, or 0% by volume.

[0067] The low-viscosity hydrocarbon oil can be obtained, for example, by hydrotreating a lamp / light oil fraction obtained by atmospheric distillation of crude oil or a cracked light oil fraction obtained by cracking a residual oil feedstock containing atmospheric residue oil of crude oil or its vacuum residue oil, and fractionating the fraction in such a manner that the above-mentioned distillation properties, in particular hydrocarbons having 12 to 16 carbon atoms or 13 to 18 carbon atoms, become the main components (for example, 50% by mass or more, in particular 80% by mass or more), thereby obtaining the low-viscosity hydrocarbon oil.

[0068] The content of the low-viscosity hydrocarbon oil is preferably 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, based on the total amount of hydrocarbon oil contained in the refrigerating machine oil, from the viewpoint of further reducing the viscosity of the refrigerating machine oil, and for example, may be 99.5% by mass or less. The content of the low-viscosity hydrocarbon oil is preferably 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, based on the total amount of the refrigerating machine oil, from the viewpoint of further reducing the viscosity of the refrigerating machine oil, and for example, may be 99.5% by mass or less.

[0069] The kinematic viscosity of the high-viscosity hydrocarbon oil at 40° C. is preferably 300 mm / s from the viewpoint of further improving the wear resistance. 2 / s or more, 350mm 2 / s or more, 400mm 2 / s or above, or 450mm 2 / s or more, for example, 1000mm 2 / s or less, 800mm 2 / s or less, 600mm 2 / s or less, or 500mm 2 / s or less.

[0070] The kinematic viscosity of the high viscosity hydrocarbon oil at 100°C may be, for example, 10 mm 2 / s or more, 20mm 2 / s or above, or 30mm 2 / s or more, can be 100mm 2 / s or less, 50mm 2 / s or less, or 40mm 2 / s or less.

[0071] The viscosity index of the high viscosity hydrocarbon oil may be, for example, 0 or more, 50 or more, or 80 or more, or 300 or less, 140 or less, or 100 or less. The viscosity index in this specification refers to a viscosity index measured in accordance with JIS K2283:2000.

[0072] The flash point of the high-viscosity hydrocarbon oil may be, for example, 200°C or higher, 250°C or higher, or 300°C or higher, and may be 500°C or lower, 450°C or lower, or 400°C or lower.

[0073] As the high-viscosity hydrocarbon oil, it is preferred to have the above-mentioned properties, but there is no particular limitation thereto. For example, a residual oil-based hydrocarbon base material in a crude oil refining process can be used. As the residual oil-based hydrocarbon base material, for example, there can be mentioned: a residual oil of atmospheric distillation of crude oil, a residual oil of vacuum distillation of the residual oil of atmospheric distillation, a deasphalted oil of these residual oils based on propane or the like, a solvent extraction extract oil of the aforementioned deasphalted oil based on furfural or the like, a solvent extraction residual oil liquid oil of the aforementioned deasphalted oil, and a residual oil-based hydrocarbon base material obtained by subjecting these oils to a refining treatment such as hydrocracking, hydrofining, solvent dewaxing or hydrodewaxing. Among these, a refined oil obtained by hydrofining a solvent extraction residual oil liquid of a deasphalted oil of a vacuum distillation residual oil, and subjecting it to solvent dewaxing or hydrodewaxing is particularly preferred.

[0074] The residual carbon content of the high-viscosity hydrocarbon oil is not particularly limited, but in order to further improve the wear resistance, it is preferably 0.1 mass % or more, 0.2 mass % or more, 0.3 mass % or more, and preferably 10 mass % or less, 5 mass % or less, 1 mass % or less, or 0.8 mass % or less.

[0075] The ASTM chromaticity of the high-viscosity hydrocarbon oil B may be 6.0 or less, 4.0 or less, or 3.0 or less, may be L0.5, or may be 0.5 or more, or 1.0 or more, from the viewpoint of the color tone of the refrigerating machine oil.

[0076] The content of the high-viscosity hydrocarbon oil is preferably 0.5% by mass or more, 1% by mass or more, 2% by mass or more, or 3% by mass or more, based on the total amount of hydrocarbon oil contained in the refrigerating machine oil, from the viewpoint of further improving the wear resistance, and for example, it may be 10% by mass or less, 9% by mass or less, 8% by mass or less, 7% by mass or less, 6% by mass or less, or 5% by mass or less. The content of the high-viscosity hydrocarbon oil is preferably 0.5% by mass or more, 1% by mass or more, 2% by mass or more, or 3% by mass or more, based on the total amount of hydrocarbon oil contained in the refrigerating machine oil, from the viewpoint of further improving the wear resistance, and for example, it may be 10% by mass or less, 9% by mass or less, 8% by mass or less, 7% by mass or less, 6% by mass or less, or 5% by mass or less.

[0077] The refrigeration oil may further contain hydrocarbon oils other than the above-mentioned low-viscosity hydrocarbon oil and high-viscosity hydrocarbon oil, and may further contain oxygenated oil. The refrigeration oil may further contain additives. As additives, anti-wear agents, antioxidants, acid capture agents, extreme pressure agents, metal deactivators, pour point depressants, detergent dispersants, etc. may be cited. The content of these additives may be 10% by mass or less or 5% by mass, taking the total amount of the refrigeration oil as a reference.

[0078] For refrigeration oil, from the viewpoint of improving wear resistance, it is preferred to contain an anti-wear agent as an additive. As an anti-wear agent, for example, a phosphorus-containing anti-wear agent can be cited. As a phosphorus-containing anti-wear agent, for example, phosphate esters, thiophosphate esters, acid phosphate esters, amine salts of acid phosphate esters, chlorinated phosphate esters, etc. can be cited. The anti-wear agent (preferably a phosphorus-containing anti-wear agent) can be used alone or in combination of two or more. The phosphorus-containing anti-wear agent is preferably selected from one or more of phosphate esters and thiophosphate esters.

[0079] Examples of the phosphoric acid ester include tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, triundecyl phosphate, tridodecyl phosphate, tritridecyl phosphate, tritetradecyl phosphate, tripentadecyl phosphate, trihexadecyl phosphate, triheptadecyl phosphate, trioctadecyl phosphate, trioleyl phosphate, triphenyl phosphate, tricresyl phosphate, triethylphenyl phosphate, tributylphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, and cresyl diphenyl phosphate. The phosphoric acid ester is preferably triphenyl phosphate or tricresyl phosphate.

[0080] Examples of the phosphorothioate include tributyl phosphorothioate, tripentyl phosphorothioate, trihexyl phosphorothioate, triheptyl phosphorothioate, trioctyl phosphorothioate, trinonyl phosphorothioate, tridecyl phosphorothioate, triundecyl phosphorothioate, tridodecyl phosphorothioate, tritridecyl phosphorothioate, tritetradecyl phosphorothioate, tripentadecyl phosphorothioate, trihexadecyl phosphorothioate, triheptadecyl phosphorothioate, trioctadecyl phosphorothioate, trioleyl phosphorothioate, triphenyl phosphorothioate, tricresyl phosphorothioate, trixylyl phosphorothioate, cresyldiphenyl phosphorothioate, and xylyldiphenyl phosphorothioate. The phosphorothioate is preferably triphenyl phosphorothioate.

[0081] The content of the anti-wear agent (preferably a phosphorus-containing anti-wear agent) can be, for example, 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, or 5% by mass or less, 4% by mass or less, or 3% by mass or less, based on the total amount of the refrigeration oil.

[0082] The refrigerator oil of this embodiment can exist in the refrigerator in the state of a refrigerator working fluid composition mixed with a refrigerant. That is, one embodiment of the present invention is a refrigerator working fluid composition, which contains: the above-mentioned refrigerator oil and a refrigerant. The content of the refrigerator oil in the refrigerator working fluid composition can be more than 1 mass part or more than 2 mass parts relative to 100 mass parts of the refrigerant, and can be less than 500 mass parts or less than 400 mass parts.

[0083] The refrigerant preferably contains hydrocarbons. The content of hydrocarbons may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more based on the total amount of the refrigerant.

[0084] The hydrocarbon is preferably a hydrocarbon having 1 to 5 carbon atoms, and more preferably a hydrocarbon having 2 to 4 carbon atoms. Specific examples of the hydrocarbon include methane, ethylene, ethane, propylene, propane (R290), cyclopropane, n-butane, isobutane (R600a), cyclobutane, methylcyclopropane, 2-methylbutane, n-pentane, or a mixture of two or more thereof. The hydrocarbon is preferably a hydrocarbon that is a gas at 25° C. and 1 atmosphere, and more preferably propane, n-butane, isobutane, 2-methylbutane, or a mixture thereof.

[0085] The refrigerant may contain, in addition to or instead of hydrocarbons, one or more refrigerants selected from saturated fluorinated hydrocarbons, unsaturated fluorinated hydrocarbons, fluorinated ethers such as perfluoroethers, bis(trifluoromethyl)sulfide, trifluoromethane iodide, and natural refrigerants such as ammonia and carbon dioxide.

[0086] Example

[0087] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.

[0088] The low viscosity hydrocarbon oils 1 to 3 used in the examples and comparative examples are as follows. Since the aromatic components of these hydrocarbon oils were less than 1% by mass, they were not subjected to chromatographic fractionation, and all of them were regarded as saturated hydrocarbons, and the hydrocarbon type analysis based on the GC-TOFMS method was directly performed. The properties of these low viscosity hydrocarbon oils are shown in Table 1.

[0089] Low viscosity hydrocarbon oil 1: a mineral oil-based hydrocarbon oil obtained by hydrotreating and fractionating a hydrocracked light oil containing a vacuum distillation residue as a raw material (aromatic component <1 mass %, ASTM chromaticity: 0)

[0090] Low viscosity hydrocarbon oil 2: Mineral oil-based hydrocarbon oil obtained by hydrodesulfurizing and fractionating the atmospheric distillate of crude oil (aromatic component <1% by mass, ASTM color: 0)

[0091] Low viscosity hydrocarbon oil 3: Mineral oil-based hydrocarbon oil obtained by hydrodesulfurizing and fractionating the atmospheric distillate of crude oil (aromatic component <1% by mass, ASTM color: 0)

[0092] [Table 1]

[0093]

[0094] Furthermore, the solvent extraction residue of the deasphalted oil of the vacuum distillation residue oil was hydrotreated and solvent dewaxed to obtain high viscosity hydrocarbon oils 1 and 2 having the following properties.

[0095] High viscosity hydrocarbon oil 1 (40℃ kinematic viscosity: 479.4mm 2 / s, 100℃ kinematic viscosity: 31.72mm 2 / s, viscosity index 97, flash point: >300 °C, residual carbon content: 0.51 mass%, ASTM color: L2.0)

[0096] High-viscosity hydrocarbon oil 2 (kinematic viscosity at 40 °C: 458 mm 2 / s, kinematic viscosity at 100 °C: 31.2 mm 2 / s, viscosity index 98, flash point: >300 °C, residual carbon content: 0.5 mass%, ASTM color: L2.0)

[0097] The above hydrocarbon oils were used in the composition shown in Table 2 (mass% based on the total amount of hydrocarbon oil). 98.3 mass% of each hydrocarbon oil and 1.7 mass% of a phosphorus-containing anti-wear agent formed from a mixture of tricresyl phosphate and triphenyl thiophosphate (both based on the total amount of refrigerating oil) were mixed to prepare refrigerating oils. For the hydrocarbon oils contained in each refrigerating oil, the aforementioned hydrocarbon type analysis was performed, and the results are shown in Table 2. In addition, the properties of each refrigerating oil are also shown in Table 2.

[0098] [Evaluation of anti-wear properties]

[0099] The anti-wear property was measured according to ASTM D3233-73 using a FALEX (test pin / V-block) test machine at a temperature of 60 °C and a rotational speed of 290 rpm to measure the wear load (Japanese: seizure load). The greater the wear load, the more excellent the anti-wear property. The results are shown in Table 2.

[0100] [Table 2]

[0101]

[0102] In addition, in Examples 5 and 6 respectively, low-viscosity hydrocarbon oil 3 was used instead of low-viscosity hydrocarbon oil 2 to prepare the refrigerating oils of Examples 7 and 8. In the obtained refrigerating oils of Examples 7 and 8, compared with the refrigerating oils of Examples 5 and 6 respectively, the amount of n-alkanes was more and the pour point was slightly higher, but further improvements in anti-wear property and low friction property equivalent or better were confirmed.

[0103] (Low-temperature precipitation test in the presence of refrigerant)

[0104] Regarding the refrigerating oils of Examples 1 to 8, the low-temperature precipitation test based on Annex A of JIS K2211 (2009) was carried out using the hydrocarbon refrigerant R600a as the refrigerant. In the range of the refrigerating oil / refrigerant ratio (mass ratio) of 1 / 99 to 99 / 1 for the mixed fluid of the refrigerating oils of Examples 1 to 8 and R600a, even when cooled to -40 °C, no hairy precipitates, granular precipitates, fogging or turbidity were generated, and no tendency to precipitate at low temperatures was confirmed.

Claims

1. A refrigeration oil comprising: The kinematic viscosity at 40°C is 6 mm 2 / s or less low viscosity hydrocarbon oil, and The kinematic viscosity at 40°C exceeds 400 mm 2 / s high viscosity hydrocarbon oil, The high-viscosity hydrocarbon oil is a residual oil-based hydrocarbon base material, and the residual oil-based hydrocarbon base material is any one selected from the group consisting of: atmospheric distillation residual oil of crude oil; vacuum distillation residual oil of the atmospheric distillation residual oil; propane-based deasphalted oil of the atmospheric distillation residual oil or the vacuum distillation residual oil; solvent extraction extract oil of the deasphalted oil, wherein the solvent is furfural; solvent extraction residual oil liquid oil of the deasphalted oil; refined oil of the atmospheric distillation residual oil, the vacuum distillation residual oil, the deasphalted oil, the solvent extraction extract oil or the solvent extraction residual oil liquid oil, wherein the refining is a refining treatment selected from at least one of hydrocracking, hydrofining, solvent dewaxing or hydrodewaxing, The content of the high-viscosity hydrocarbon oil is 0.5 mass % or more and less than 10 mass % based on the total amount of hydrocarbon oil contained in the refrigerating machine oil. The flash point of the refrigerating machine oil is 130° C. or lower, and the residual carbon content of 10% residual oil is 0.02% by mass or more.

2. The refrigerating machine oil according to claim 1, in, The content of the low-viscosity hydrocarbon oil is 85% by mass or more based on the total amount of the refrigerating machine oil.

3. The refrigerating machine oil according to claim 1 or 2, in, The content of the high-viscosity hydrocarbon oil is 10% by mass or less based on the total amount of the refrigerating machine oil.

4. The refrigerating machine oil according to claim 1 or 2, in, The 90% distillation temperature of the refrigerating machine oil is 270° C. or lower.

5. The refrigerating machine oil according to claim 3, in, The 90% distillation temperature of the refrigerating machine oil is 270° C. or lower.

6. A working fluid composition for a refrigerator, comprising: The refrigerating machine oil according to any one of claims 1 to 5, and refrigerant.

7. The working fluid composition for a refrigerator according to claim 6, in, The refrigerant includes a hydrocarbon.

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