Refrigeration oil and refrigeration fluid components used in refrigeration equipment

Abstract

This refrigerator oil includes a hydrocarbon base oil with a 90% distillation temperature of 270ºC or less.

Description

[Technical Field]

[0001] The present invention relates to a refrigerating machine oil and a working fluid composition for a refrigerating machine. [Background technology]

[0002] In refrigerators, there is increasing pressure to replace refrigerants with relatively high Global Warming Potential (GWP) with low GWP refrigerants, for example, less than 150. Examples of low GWP refrigerants include carbon dioxide (R744) refrigerant and hydrocarbon refrigerants.

[0003] On the other hand, there is also a demand for energy conservation in refrigerators. Generally, the lower the viscosity of a refrigerator oil, the more the stirring resistance and friction of sliding parts can be reduced, so lowering the viscosity of a refrigerator oil leads to energy conservation in refrigerators. For example, Patent Document 1 discloses a refrigerator oil with a VG3 or higher and a VG8 or lower. Also, for example, Patent Document 2 discloses a refrigerator oil containing a mixed base oil made of a low-viscosity base oil and a high-viscosity base oil. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2006 / 062245 [Patent Document 2] International Publication No. 2007 / 105452 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the viscosity of the refrigeration oil is low, it becomes difficult to maintain an oil film on the sliding parts, which may result in an increase in the coefficient of friction, etc. Therefore, one aspect of the present invention aims to provide a refrigeration oil that is low in viscosity but can reduce the coefficient of friction. [Means for solving the problem]

[0006] One aspect of the present invention is a refrigeration oil containing a hydrocarbon base oil having a 90% distillation temperature of 270°C or lower.

[0007] The initial boiling point of the hydrocarbon base oil may be 140°C or higher. The refrigerating machine oil may further contain a phosphorus-containing antiwear agent. The flash point of the refrigerating machine oil may be 70°C or higher. The content of hydrocarbons having 12 to 16 carbon atoms in the hydrocarbon base oil contained in the refrigerating machine oil may be 80% by mass or higher. The difference between the 90% distillation temperature and the 10% distillation temperature of the refrigerating machine oil may be 5°C or higher and 40°C or lower. The residual carbon content of the 10% bottoms of the refrigerating machine oil may be 0.02% by mass or higher. The content of n-paraffins in the hydrocarbon base oil contained in the refrigerating machine oil may be 5% by mass or higher and 50% by mass or lower. The 90% distillation temperature of the refrigerating machine oil may be 270°C or lower.

[0008] Another aspect of the present invention may be a working fluid composition for a refrigerating machine, comprising the refrigerating machine oil and a refrigerant. The refrigerant may contain a hydrocarbon. [Effects of the Invention]

[0009] According to one aspect of the present invention, it is possible to provide a refrigerating machine oil that has a low viscosity and yet can reduce the coefficient of friction. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described in detail. One embodiment of the present invention is a refrigeration oil containing a hydrocarbon base oil having a 90% distillation temperature of 270°C or less. By using a hydrocarbon base oil having a predetermined 90% distillation temperature, this refrigeration oil can have a low viscosity and a reduced friction coefficient. The 90% distillation temperature is measured in accordance with the atmospheric pressure method described in JIS K2254:2018. Hereinafter, the distillation properties of the hydrocarbon base oil and the refrigeration oil are also measured in accordance with this method.

[0011] From the viewpoint of further reducing the friction coefficient, the 90% distillation temperature (T90) of the hydrocarbon base oil may be preferably 267°C or less, 266°C or less, 265°C or less, 264°C or less, 263°C or less, 262°C or less, or 261°C or less, for example, 220°C or more, 230°C or more, 240°C or more, 245°C or more, or 250°C or more.

[0012] From the viewpoint of further reducing the friction coefficient, the initial boiling point (IBP) of the hydrocarbon base oil may be preferably 140°C or more, 170°C or more, 190°C or more, 200°C or more, 210°C or more, 220°C or more, 230°C or more, or 240°C or more, and may be 260°C or less, 255°C or less, or 250°C or less.

[0013] From the viewpoint of further reducing the friction coefficient, the 10% distillation temperature (T10) of the hydrocarbon base oil may be preferably 200°C or more, 210°C or more, 220°C or more, 230°C or more, or 240°C or more, and may be 260°C or less, 255°C or less, or 250°C or less.

[0014] From the viewpoint of further reducing the friction coefficient, the 50% distillation temperature (T50) of the hydrocarbon base oil may preferably be 210°C or more, 220°C or more, 230°C or more, 240°C or more, or 245°C or more, and may be 265°C or less, 260°C or less, 255°C or less, or 250°C or less.

[0015] From the viewpoint of further reducing the friction coefficient, the distillation end point (EP) of the hydrocarbon base oil may be preferably 250°C or more, 260°C or more, 270°C or more, 275°C or more, or 280°C or more, and may be 320°C or less, 310°C or less, 300°C or less, 295°C or less, or 290°C or less.

[0016] From the viewpoint of further reducing the friction coefficient, the difference between T90 and T10 of the hydrocarbon base oil (T90-T10) may be 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.

[0017] The total distillate amount of the hydrocarbon base 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 may be 99.9% by volume or less. The residual amount of the hydrocarbon base oil may be, for example, 0.1% by volume or more, and may be 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 amount of the hydrocarbon base oil may be, for example, 1% by volume or less, 0.5% by volume or less, or 0.1% by volume or less, or may be 0% by volume.

[0018] The kinematic viscosity of the hydrocarbon base oil at 40°C is, for example, 1.0 mm 2 / s or more, 1.5mm 2 / s or more, or 2.0 mm 2 / s or more, and 6.0 mm 2 / s or less, 5.0mm 2 / s or less, 4.5mm 2 / s or less, 4.0mm 2 / s or less, 3.5mm 2 / s or less, or 3.0 mm 2 The kinematic viscosity in this specification refers to the kinematic viscosity measured in accordance with JIS K2283:2000.

[0019] The kinematic viscosity of hydrocarbon base oil at 100°C is, for example, 0.5 mm 2 / s or more, 0.7mm 2 / s or more, or 1.0 mm 2 / s or more, and 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 1.1 mm 2 / s or less.

[0020] The density of the hydrocarbon base oil is, for example, 0.78 g / cm 3 More than 0.79g / cm 3 More than 0.80g / cm 3More than 0.81g / cm 3 or more, or 0.82 g / cm 3 or more, and 3 Below, 0.83g / cm 3 Below, 0.82g / cm 3 or less than 0.81 g / cm 3 The density in this specification refers to the density at 15°C measured in accordance with the "oscillating method" described in JIS K2249-1:2011.

[0021] The flash point of the hydrocarbon base 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, and may be 150°C or lower, 140°C or lower, or 130°C or lower. Increasing the initial boiling point of the hydrocarbon base oil can increase the flash point and further improve safety. In this specification, the flash point means the flash point measured in accordance with the Cleveland Open Chamber (COC) method described in JIS K2265-4:2007.

[0022] The pour point of the hydrocarbon base 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. In this specification, the pour point refers to the pour point measured in accordance with JIS K2269:1987.

[0023] Examples of hydrocarbon base oils having the above properties include mineral hydrocarbon base oils, synthetic hydrocarbon base oils, and mixed base oils thereof. Examples of mineral hydrocarbon base oils include paraffinic or naphthenic refined mineral oils that are obtained by using crude oil or its distillation residue as a raw material and refining it through an appropriate combination of conventional petroleum refining processes (solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid washing, clay treatment, distillation, etc.). Examples of synthetic hydrocarbon base oils include poly-α-olefins or hydrogenated products thereof, isoparaffins, alkylbenzenes, alkylnaphthalenes, etc. These hydrocarbon base oils can be used alone or in combination of two or more.

[0024] From the viewpoint of easily obtaining the above-mentioned properties, the hydrocarbon base oil is preferably a mineral hydrocarbon base oil. More specifically, for example, a kerosene / gas oil fraction obtained by atmospheric distillation of crude oil, or a cracked gas oil fraction obtained by cracking a residual oil feedstock including an atmospheric residue of crude oil or its vacuum residue, is hydrorefined and fractionated to have the above-mentioned distillation properties, in particular, to have hydrocarbons having 12 to 16 carbon atoms or 13 to 18 carbon atoms as the main components (for example, 50 mass % or more, particularly 80 mass % or more), thereby easily obtaining a hydrocarbon base oil having the above-mentioned properties.

[0025] The refrigerating machine oil may contain only a hydrocarbon base oil having the above properties (hereinafter also referred to as "hydrocarbon base oil A") as the base oil, or may further contain other base oils in addition to the hydrocarbon base oil A. The content of the hydrocarbon base oil A may be 50% by mass or more, 70% by mass or more, 90% by mass or more, or 95% by mass or more, based on the total amount of base oils contained in the refrigerating machine oil. The content of the hydrocarbon base oil A may be 50% by mass or more, 70% 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.

[0026] The other base oil may be, for example, a hydrocarbon base oil other than the hydrocarbon base oil having the above properties (hereinafter also referred to as "hydrocarbon base oil B"), an oxygen-containing base oil, etc., and is preferably hydrocarbon base oil B. Hydrocarbon base oil B may be, for example, a hydrocarbon base oil having a higher kinematic viscosity than hydrocarbon base oil A (for example, kinematic viscosity at 40°C, kinematic viscosity at 100°C).

[0027] The kinematic viscosity of hydrocarbon base oil B at 40°C is, for example, 100mm 2 / s or more, 200mm 2 / s or more, 300mm 2 / s or more, 400mm 2 / s or more, or 450 mm 2 / s or more, and 2 / s or less, 800mm 2 / s or less, 600mm 2 / s or less, or 500 mm 2 / s or less.

[0028] The kinematic viscosity of hydrocarbon base oil B at 100°C is, for example, 10 mm 2 / s or more, 20mm 2 / s or more, or 30 mm 2 / s or more, and 2 / s or less, 50mm 2 / s or less, or 40 mm 2 / s or less.

[0029] The viscosity index of the hydrocarbon base oil B may be, for example, 0 or more, 50 or more, or 80 or more, and may be 300 or less, 140 or less, or 100 or less. The viscosity index in this specification means a viscosity index measured in accordance with JIS K2283:2000.

[0030] The flash point of the hydrocarbon base oil B 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.

[0031] The hydrocarbon base oil B is preferably one having the above properties, and is not otherwise particularly limited, but for example, a residual hydrocarbon base oil from a crude oil refining process can be used. Examples of residual hydrocarbon base oils include atmospheric distillation residual oil of crude oil, vacuum distillation residual oil of the atmospheric distillation residual oil, deasphalted oil of these residual oils with propane or the like, solvent extracted extract oil of the deasphalted oil with furfural or the like, solvent extracted raffinate oil of the deasphalted oil, and refined oils obtained by refining these oils through hydrocracking, hydrorefining, solvent dewaxing, or hydrodewaxing. Among these, refined oils obtained by hydrorefining a solvent extracted raffinate of deasphalted oil of vacuum distillation residual oil, followed by solvent dewaxing or hydrodewaxing, are particularly preferred.

[0032] The residual carbon content of hydrocarbon base oil B is not particularly limited, but in terms of further improving wear resistance, it may be preferably 0.1 mass % or more, 0.2 mass % or more, or 0.3 mass % or more, and may be preferably 10 mass % or less, 5 mass % or less, 1 mass % or less, or 0.8 mass % or less.

[0033] From the viewpoint of the hue of the refrigeration oil, the ASTM color of the hydrocarbon base oil B may be 6.0 or less, 4.0 or less, or 3.0 or less, and may be L0.5, 0.5 or more, or 1.0 or more.

[0034] The content of the other base oil (preferably hydrocarbon base oil B) may be 0.5% by mass or more, 1% by mass or more, 2% by mass or more, or 3% by mass or more, and may be 50% by mass or less, 30% by mass or less, 10% by mass or less, or 5% by mass or less, based on the total amount of base oils contained in the refrigerating machine oil. The content of the other base oil (preferably hydrocarbon base oil B) may be 0.5% by mass or more, 1% by mass or more, 2% by mass or more, or 3% by mass or more, and may be 50% by mass or less, 30% by mass or less, 10% by mass or less, or 5% by mass or less, based on the total amount of the refrigerating machine oil.

[0035] The refrigerating machine oil may further contain additives in addition to the above-mentioned base oil. Examples of additives include antiwear agents, antioxidants, acid scavengers, extreme pressure agents, metal deactivators, pour point depressants, detergents and dispersants. The content of these additives may be 10% by mass or less or 5% by mass or less based on the total amount of the refrigerating machine oil.

[0036] From the viewpoint of improving wear resistance, the refrigerating machine oil preferably contains an anti-wear agent as an additive. Examples of the anti-wear agent include phosphorus-containing anti-wear agents. Examples of the phosphorus-containing anti-wear agent include phosphate esters, thiophosphate esters, acid phosphate esters, amine salts of acid phosphate esters, and chlorinated phosphate esters. The anti-wear agent (preferably phosphorus-containing anti-wear agents) is used alone or in combination of two or more. The phosphorus-containing anti-wear agent is preferably one or more selected from phosphate esters and thiophosphate esters.

[0037] 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, tri(ethylphenyl)phosphate, tri(butylphenyl)phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, etc. The phosphoric acid ester is preferably triphenyl phosphate or tricresyl phosphate.

[0038] Examples of thiophosphate esters 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, trixylenyl phosphorothioate, cresyl diphenyl phosphorothioate, and xylenyl diphenyl phosphorothioate. The thiophosphate is preferably triphenyl phosphorothioate.

[0039] The content of the anti-wear agent (preferably a phosphorus-containing anti-wear agent) may be, for example, 0.1 mass % or more, 0.5 mass % or more, or 1 mass % or more, and may be 5 mass % or more, 4 mass % or less, or 3 mass % or less, based on the total amount of the refrigerating machine oil.

[0040] From the viewpoint of further reducing the friction coefficient, the initial boiling point (IBP) of the refrigerating machine oil may preferably be 140°C or more, 170°C or more, 190°C or more, 200°C or more, 210°C or more, 220°C or more, 230°C or more, or 240°C or more, and may be 260°C or less, 255°C or less, or 250°C or less.

[0041] From the viewpoint of further reducing the friction coefficient, the 10% distillation temperature (T10) of the refrigerating machine oil may preferably be 200°C or more, 210°C or more, 220°C or more, 230°C or more, or 240°C or more, and may be 260°C or less, 255°C or less, or 250°C or less.

[0042] From the viewpoint of further reducing the friction coefficient, the 50% distillation temperature (T50) of the refrigerating machine oil may preferably be 210°C or more, 220°C or more, 230°C or more, 240°C or more, or 245°C or more, and may be 265°C or less, 260°C or less, 255°C or less, or 250°C or less.

[0043] From the viewpoint of further reducing the friction coefficient, the 90% distillation temperature (T90) of the refrigerating machine oil may preferably be 220°C or more, 230°C or more, 240°C or more, 245°C or more, or 250°C or more, and may be 270°C or less, 267°C or less, 266°C or less, 265°C or less, 264°C or less, 263°C or less, 262°C or less, or 261°C or less.

[0044] From the viewpoint of further reducing the friction coefficient, the distillation end point (EP) of the refrigerating machine oil may preferably be 250°C or more, 260°C or more, 270°C or more, 275°C or more, or 280°C or more, and may be 320°C or less, 310°C or less, 300°C or less, 295°C or less, or 290°C or less.

[0045] From the viewpoint of further reducing the coefficient of friction, the difference between T90 and T10 of the refrigerating machine oil (T90-T10) 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.

[0046] The total distillate amount of the refrigerating machine oil may be, for example, 90% by volume or more, 93% by volume or more, or 95% by volume or more, or may be 99% by volume or less. The residual amount of the refrigerating machine oil may 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 amount of the refrigerating machine oil may be, for example, 1% by volume or less, 0.5% by volume or less, or 0.1% by volume or less, or may be 0% by volume.

[0047] The kinematic viscosity of refrigerating oil at 40°C is, for example, 1.0 mm 2 / s or more, 1.5mm 2 / s or more, or 2.0 mm 2 / s or more, and 6.0 mm 2 / s or less, 5.0mm 2 / s or less, 4.5mm 2 / s or less, 4.0mm 2 / s or less, 3.5mm 2 / s or less, or 3.0 mm 2 / s or less.

[0048] The kinematic viscosity of refrigerating oil at 100°C is, for example, 0.5 mm 2 / s or more, 0.7mm 2 / s or more, or 1.0 mm 2 / s or more, and 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 1.1 mm 2 / s or less.

[0049] The density of refrigerating machine oil is, for example, 0.78 g / cm 3More than 0.79g / cm 3 or more, or 0.80 g / cm 3 may be 0.85 g / cm or more, 3 Below, 0.84g / cm 3 or less, or 0.83 g / cm 3 It may be the following:

[0050] 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 may be 150°C or lower, 140°C or lower, or 130°C or lower.

[0051] 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.

[0052] From the viewpoint of further reducing the friction coefficient, the carbon residue of the 10% residual oil of the refrigerating machine oil may preferably be 0.01% by mass or more, 0.02% by mass or more, 0.05% by mass or more, 0.08% by mass or more, or 0.1% by mass or more, and may be, for example, 0.6% by mass or less, 0.5% by mass or less, or 0.4% by mass or less. Note that the carbon residue in this specification refers to the carbon residue measured by a micro method in accordance with JIS K2270-2:2009. The carbon residue in the 10% residual oil in this specification refers to the carbon residue measured by the same method for the residual oil obtained by distilling the refrigerating machine oil and removing the distillate up to a volume fraction of 90%.

[0053] The content of hydrocarbons having 12 to 16 carbon atoms in the refrigerating machine oil or in the hydrocarbon base oil contained in the refrigerating machine oil (C12-16 component content) may be preferably 80 mass% or more, 85 mass% or more, or 90 mass% or more, and may be 97 mass% or less, 96 mass% or less, or 95 mass% or less, based on the total amount of the hydrocarbon base oil, from the viewpoint of further reducing the friction coefficient.

[0054] The content of hydrocarbons having 13 to 18 carbon atoms in the refrigerating machine oil or in the hydrocarbon base oil contained in the refrigerating machine oil (amount of C13-18 components) may be preferably 80 mass% or more, 85 mass% or more, or 90 mass% or more, and may be 99 mass% or less, 98 mass% or less, or 97 mass% or less, based on the total amount of the hydrocarbon base oil, from the viewpoint of further reducing the friction coefficient.

[0055] The content of n-paraffins in the refrigerating machine oil or in the hydrocarbon base oil contained in the refrigerating machine oil may be, from the viewpoint of being able to further reduce the friction coefficient, preferably 0.5 mass% or more, 2 mass% or more, 5 mass% or more, 8 mass% or more, or 9 mass% or more, based on the total amount of the hydrocarbon base oil, and may further be 10 mass% or more, 15 mass% or more, or 20 mass% or more, and may be 50 mass% or less, 30 mass% or less, or 25 mass% or less, and from the viewpoint of low-temperature fluidity, may be 40 mass% or less, 30 mass% or less, 20 mass% or less, or 15 mass% or less.

[0056] From the viewpoint of further reducing the friction coefficient, the content of paraffin in the refrigerating machine oil or in the hydrocarbon base oil contained in the refrigerating machine oil may be preferably 30 mass% or more, 40 mass% or more, 50 mass% or more, 55 mass% or more, or 60 mass% or more, and may be 100 mass% or less, 90 mass% or less, or 80 mass% or less, based on the total amount of the hydrocarbon base oil.

[0057] The content of 1- to 6-ring cycloparaffins (hereinafter simply referred to as "cycloparaffins") in the refrigerating machine oil or in the hydrocarbon base oil contained in the refrigerating machine oil may be preferably 70 mass% or less, 60 mass% or less, 50 mass% or less, 45 mass% or less, or 40 mass% or less, and may be 0 mass% or more, 10 mass% or more, 20 mass% or more, 30 mass% or more, or 35 mass% or more, based on the total amount of the hydrocarbon oil, from the viewpoint of being able to further reduce the friction coefficient.

[0058] From the viewpoint of further reducing the friction coefficient, the ratio of the paraffin to the cycloparaffin (paraffin / cycloparaffin) may be 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 may be preferably 100 or less, 50 or less, 10 or less, 5 or less, or 4 or less.

[0059] The aromatic content in the refrigerating machine oil or in the hydrocarbon base oil contained in the refrigerating machine oil may be preferably 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.

[0060] In this specification, the contents of hydrocarbons having 12 to 16 carbon atoms, hydrocarbons having 13 to 18 carbon atoms, n-paraffins, paraffins, cycloparaffins, and aromatic hydrocarbon oils in the refrigerating machine oil or the hydrocarbon base oil contained therein are determined by fractionating the sample to be analyzed into saturated hydrocarbon oils and aromatic hydrocarbon oils by silica gel chromatography, and then performing hydrocarbon type analysis on each of the oils using GC-TOFMS, which combines gas chromatography with mass spectrometry using FI ionization. Examples of analytical conditions are shown below. The contents of saturated hydrocarbon oils and aromatic hydrocarbon oils may also be determined by fractionation using silica gel chromatography. (Gas chromatography conditions) Column: phenomenex ZB-1MS Injection temperature: 350℃ Temperature rise conditions: 50℃ to 350℃ (heat rise rate: 5℃ / min) Carrier gas: Helium Injection method: Split Sample injection volume: 1 μL (10% toluene solution) (MS conditions) Counter electrode voltage: -10kV Ionization method: FI (field ionization) Ion source temperature: room temperature Mass number measurement range: m / z 35-500

[0061] Among the mass spectra obtained as a result of GC-TOFMS analysis, the types of carbon numbers (Cn H 2n+z The percentage of ionic strength of each component (where n is an integer and z is an even number between -18 and 2) can be calculated from the percentage of total ionic strength, and in this specification, the content (mass %) of each component is assumed to be approximately the same as the ionic strength % of each component. Note that if the aromatic hydrocarbon content of a sample fractionated by silica gel chromatography is less than 1 mass %, this chromatographic fractionation may be omitted and hydrocarbon type analysis performed by GC-TOFMS. In this case, the content of each component is calculated assuming that all components are saturated hydrocarbons.

[0062] The refrigerating machine oil according to this embodiment may be present in a refrigerating machine in the form of a working fluid composition for a refrigerating machine mixed with a refrigerant. That is, one embodiment of the present invention is a working fluid composition for a refrigerating machine containing the above-mentioned refrigerating machine oil and a refrigerant. The content of the refrigerating machine oil in the working fluid composition for a refrigerating machine may be 1 part by mass or more or 2 parts by mass or more, and may be 500 parts by mass or less or 400 parts by mass or less, per 100 parts by mass of the refrigerant.

[0063] The refrigerant preferably contains a hydrocarbon, and the hydrocarbon content 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 mass of the refrigerant.

[0064] The hydrocarbon is preferably a hydrocarbon having 1 to 5 carbon atoms, more preferably a hydrocarbon having 2 to 4 carbon atoms. Specific examples of the hydrocarbon include methane, ethylene, ethane, propylene, propane (R290), cyclopropane, normal butane, isobutane (R600a), cyclobutane, methylcyclopropane, 2-methylbutane, normal pentane, or a mixture of two or more of these. The hydrocarbon is preferably a gaseous hydrocarbon at 25°C and 1 atmospheric pressure, more preferably propane, normal butane, isobutane, 2-methylbutane, or a mixture of these.

[0065] In addition to or instead of hydrocarbons, the refrigerant may contain one or more refrigerants selected from saturated fluorohydrocarbons, unsaturated fluorohydrocarbons, fluorinated ethers such as perfluoroethers, bis(trifluoromethyl) sulfide, trifluoroiodomethane, and natural refrigerants such as ammonia and carbon dioxide. [Example]

[0066] The present invention will be described in more detail below based on examples, but the present invention is not limited to the following examples.

[0067] The hydrocarbon base oils A1 to A3 and a1 used in the examples and comparative examples are as follows. Because the aromatic content of these hydrocarbon base oils was less than 1% by mass, they were not subjected to chromatographic fractionation, and were all considered to be saturated hydrocarbons, and were directly subjected to hydrocarbon type analysis by the GC-TOFMS method described above. The properties of these hydrocarbon base oils are shown in Table 1. Hydrocarbon base oil A1: Mineral hydrocarbon oil obtained by hydrotreating and fractionating hydrocracked diesel fuel containing vacuum distillation residue (aromatic content <1% by mass, ASTM color: 0) Hydrocarbon base oil A2: Mineral hydrocarbon oil obtained by hydrodesulfurizing and fractionating crude oil atmospheric distillate (aromatic content <1% by mass, ASTM color: 0) Hydrocarbon base oil A3: Mineral hydrocarbon oil obtained by hydrodesulfurizing and fractionating crude oil atmospheric distillate (aromatic content <1% by mass, ASTM color: 0) Hydrocarbon base oil a1: Mineral hydrocarbon oil obtained by hydrotreating and fractionating hydrocracked diesel fuel containing vacuum distillation residue (aromatic content <1% by mass, ASTM color: 0)

[0068] [Table 1]

[0069] Furthermore, a solvent-extracted raffinate obtained from deasphalted oil of vacuum distillation residue was hydrorefined and solvent dewaxed to obtain a hydrocarbon base oil B having the properties shown below. Hydrocarbon base oil B1 (40°C kinematic viscosity: 479.4 mm 2 / s, 100℃ kinematic viscosity: 31.72mm 2 / s, viscosity index 97, flash point: >300℃, residual carbon content: 0.51% by mass, ASTM color: L2.0) Hydrocarbon base oil B2 (40°C kinematic viscosity: 458mm 2 / s, 100℃ kinematic viscosity: 31.2mm 2 / s, viscosity index 98, flash point: >300℃, residual carbon content: 0.5% by mass, ASTM color: L2.0)

[0070] Using the above hydrocarbon base oils, base oils were prepared with the compositions shown in Table 2 (mass % based on the total amount of base oil). Refrigerating machine oils were prepared by mixing 98.3 mass % of each base oil with 1.7 mass % of a phosphorus-containing antiwear agent consisting of a mixture of tricresyl phosphate and triphenyl phosphorothioate (all based on the total amount of refrigerating machine oil). The hydrocarbon type analysis was carried out on the hydrocarbon base oil contained in each refrigerating machine oil, and the results are shown in Table 2. Table 2 also shows the properties of each refrigerating machine oil.

[0071] [Table 2]

[0072] [Evaluation of friction characteristics] In order to evaluate the friction characteristics of each of the refrigeration oils of the Examples and Comparative Examples, the following tests were carried out. Using an MTM (Mini Traction Machine) tester (manufactured by PCS Instruments), the friction coefficient (μ) was measured under the following conditions in the lubrication region corresponding to the elastohydrodynamic lubrication region or the mixed lubrication region. The results are shown in Table 3. The smaller the friction coefficient, the better the friction characteristics. Balls and discs: standard specimens (AISI 52100 standard) Test temperature: 40℃ Sliding speed: 0.3-0.9 m / s (partial excerpt) Load: 10N Slip rate: 30% The sliding speed is |U D -U B Here, UD is the speed of the disk at the sliding part [m / s], and UB is the speed of the ball at the sliding part [m / s].

[0073] [Table 3]

[0074] Furthermore, the hydrocarbon base oil A3 was used instead of the hydrocarbon base oil A2 in each of Examples 5 to 7 to prepare the refrigerating machine oils of Examples 8 to 10. The obtained refrigerating machine oils of Examples 8 to 10 had a larger amount of n-paraffin and a slightly higher pour point than the refrigerating machine oils of Examples 5 to 7, respectively, but a further decrease in the friction coefficient was confirmed.

[0075] (Low temperature precipitation test in the presence of refrigerant) For the refrigeration oils of Examples 1 to 10, a low-temperature precipitation test was carried out in accordance with JIS K2211 (2009) Appendix A, using R600a, a hydrocarbon refrigerant, as the refrigerant. When the mixed fluids of the refrigeration oils of Examples 1 to 10 and R600a had a refrigeration oil / refrigerant ratio (mass ratio) in the range of 1 / 99 to 99 / 1, no hairy precipitates, granular precipitates, cloudiness or turbidity were generated even when cooled to -40°C, and no tendency for precipitation at low temperatures was observed.

Claims

1. A refrigeration oil containing a hydrocarbon base oil having a 90% distillation temperature of 270°C or less, the content of hydrocarbons having 12 to 16 carbon atoms in the hydrocarbon base oil contained in the refrigerating machine oil is 80 mass% or more, the content of hydrocarbons having 13 to 18 carbon atoms in the hydrocarbon base oil contained in the refrigerating machine oil is 80 mass% or more, The refrigerating machine oil has an initial boiling point of 140°C or higher, a 90% distillation temperature of 270°C or lower, and a difference between the 90% distillation temperature and the 10% distillation temperature of 5°C or higher and 40°C or lower.

2. 2. The refrigerating machine oil according to claim 1, wherein the hydrocarbon base oil has an initial boiling point of 140°C or higher.

3. 3. The refrigerator oil according to claim 1, further comprising a phosphorus-containing antiwear agent.

4. The refrigerating machine oil according to any one of claims 1 to 3, wherein the flash point of the refrigerating machine oil is 70°C or higher.

5. The refrigerating machine oil according to any one of claims 1 to 4, wherein a residual carbon content of a 10% residual oil of the refrigerating machine oil is 0.02 mass% or more.

6. The refrigerating machine oil according to any one of claims 1 to 5, wherein the content of n-paraffins in the hydrocarbon base oil contained in the refrigerating machine oil is 5% by mass or more and 50% by mass or less.

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

8. The working fluid composition for a refrigerating machine according to claim 7 , wherein the refrigerant comprises a hydrocarbon.

Images