JP5462995B2 - Refrigerator oil and working fluid composition for refrigerator - Google Patents

Description

  The present invention relates to a refrigerator oil and a working fluid composition for a refrigerator.

  Due to the problem of ozone layer destruction in recent years, CFC (chlorofluorocarbon) and HCFC (hydrochlorofluorocarbon), which have been used as refrigerants in conventional refrigeration equipment, are subject to regulation, and HFC (hydrofluorocarbon) is used as a refrigerant instead. It is being done.

When CFC and HCFC are used as refrigerants, hydrocarbon oils such as mineral oil and alkylbenzene have been suitably used as refrigeration oils, but refrigeration oils used in the coexistence when refrigerants are replaced are lubricity with refrigerants, Refrigerating machine oil needs to be developed for each refrigerant in order to show unpredictable behaviors such as compatibility, thermal / chemical stability with refrigerant, and dissolution viscosity. Therefore, as a refrigerating machine oil for HFC refrigerant, for example, polyalkylene glycol (see Patent Document 1), ester (see Patent Document 2), carbonate (see Patent Document 3), polyvinyl ether (see Patent Document 4) Etc. are being developed.
Japanese Patent Laid-Open No. 02-242888 Japanese Patent Laid-Open No. 03-200895 Japanese Patent Laid-Open No. 03-217495 Japanese Patent Laid-Open No. 06-128578

  One reason why polyalkylene glycols, esters, carbonates, polyvinyl ethers, and the like are used as refrigerant oil for HFC refrigerants is the refrigerant compatibility of refrigerant oil. That is, in the refrigerant circulation system, since the refrigeration oil is discharged from the compressor together with the refrigerant, the refrigerant oil returns to the compressor through the flow path together with the circulating refrigerant (hereinafter referred to as “oil returnability”). Is required. Therefore, it is considered that the above refrigerating machine oil having higher refrigerant compatibility than the hydrocarbon oil such as mineral oil and alkylbenzene is preferable.

  However, when refrigerating machine oil that exhibits refrigerant compatibility is used, oil return is improved, but on the other hand, refrigerating machine oil is diluted with HFC refrigerant to reduce its viscosity, resulting in poor lubrication of the compressor sliding part. May happen.

  In refrigerant circulation systems with hermetic compressors, refrigeration oil also plays a role as insulating oil, so polyalkylene glycol with high hygroscopicity and low electrical insulation is used for such refrigerant circulation systems. It is not appropriate to do. Furthermore, although ester base oils have good electrical insulation properties, they are not necessarily sufficient in terms of thermal and chemical stability, such as being easily hydrolyzed by mixed water.

  The present invention has been made in view of the above-described problems of the prior art, and when used together with an HFC refrigerant, the lubricity, refrigerant compatibility, thermal / chemical stability, and electrical insulation are sufficiently satisfied in a well-balanced manner. And it aims at providing the refrigerating machine oil which can prevent the lubrication failure of a compressor, and the fluid composition for refrigerating machines using the refrigerating machine oil.

In order to solve the above problems, the present invention provides a base oil using an alkyl diphenyl ether alone or a base oil using an alkyl diphenyl ether and a synthetic oil containing oxygen (excluding polyalkylene glycol) in combination. A refrigerating machine oil comprising a base oil having a blending amount of a synthetic oil containing oxygen of 100 parts by mass or less with respect to 100 parts by mass of the alkyl diphenyl ether and a phosphate ester, and used together with a hydrofluorocarbon refrigerant. I will provide a.

The present invention also provides a base oil using an alkyldiphenyl ether alone or a base oil using an alkyldiphenyl ether and a synthetic oil containing oxygen (excluding polyalkylene glycol) in combination, and the synthetic oil containing the oxygen A working fluid composition for a refrigerator , comprising a base oil having a blending amount of 100 parts by mass or less with respect to 100 parts by mass of the alkyl diphenyl ether , a phosphate ester, and a hydrofluorocarbon refrigerant. .

  The refrigerating machine oil and the working fluid composition for a refrigerating machine of the present invention exhibit particularly excellent effects when the hydrofluorocarbon refrigerant is HFC-134a, R407C, R404A or R410A.

  According to the present invention, when used together with an HFC refrigerant, the lubricity, refrigerant compatibility, thermal / chemical stability, and electrical insulation can be satisfactorily satisfied in a well-balanced manner, and poor lubrication of the compressor can be prevented. A refrigerating machine fluid and a refrigerating machine fluid composition using the refrigerating machine oil are provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  The refrigerating machine oil of the present invention contains alkyl diphenyl ether. Moreover, the working fluid composition for a refrigerator of the present invention contains an alkyl diphenyl ether and a hydrofluorocarbon refrigerant. In addition, the aspect containing the refrigerating machine oil and hydrofluorocarbon refrigerant | coolant of this invention is included in the working fluid composition for refrigerators of this invention.

As the alkyl diphenyl ether used in the present invention, an alkyl diphenyl ether represented by the following general formula (1) is preferably used.

In the general formula (1), R ¹ and R ² each independently represent a linear or branched alkyl group having 1 to 20 carbon atoms, m represents an integer of 1 to 3, and n represents an integer of 0 to 3. Indicates. One or more of m R ¹ and n R ² is an alkyl group. The alkyl group may be bonded to any benzene ring.

  The production method of the alkyl diphenyl ether used in the present invention is arbitrary. For example, monoalkyl diphenyl ether, dialkyl diphenyl ether, trialkyl diphenyl ether, tetraalkyl diphenyl, etc. synthesized by alkylating diphenyl ether using Friedel-Crafts reaction etc. The alkyl group may be linear and / or branched, and has 1 to 18 carbon atoms.

  By-products and unreacted products may be removed by purifying the product obtained from the raw materials as described above, but a small amount of by-products and unreacted products will have the excellent performance of the lubricating oil of the present invention. As long as it is not damaged, there is no problem even if it exists.

The number and the number of carbon atoms in the alkyl group of the alkyl ether of the present invention is not particularly limited, is preferably, 4~400mm ² / s kinematic viscosity at 40 ° C. alkyl ether is 3~500mm ² / s Is more preferable, and it is further more preferable that it is 5-300 mm < ² > / s. Further, it is preferable that kinetic viscosity at 100 ° C. of the alkyl ether is 1 to 50 mm ² / s, more preferably 1.5~40mm ² / s, still to be 2 to 30 mm ² / s preferable.

  When the kinematic viscosity of the alkyl diphenyl ether is within the above range, the lubricity, sealing properties, refrigerant compatibility, etc. tend to be satisfied in a more balanced manner.

  In the refrigerating machine oil for HFC refrigerant of the present invention, the alkyl diphenyl ether compound is mainly used as a base oil.

  In the present invention, as the base oil, only the alkyl diphenyl ether may be used alone, and the alkyl diphenyl ether and an ester (polyol ester, aromatic polycarboxylic acid ester, alicyclic dicarboxylic acid ester, etc.), You may use together with synthetic oil containing oxygen, such as polyalkylene glycol, polyvinyl ether, a ketone, silicone, polysiloxane, and perfluoroether.

  In the refrigerating machine oil of the present invention, when the alkyl diphenyl ether and the synthetic oil containing oxygen are used in combination, the amount of each is not particularly limited, but the synthetic oil containing oxygen is used with respect to 100 parts by mass of the alkyl diphenyl ether. The amount is preferably 100 parts by mass or less, and more preferably 80 parts by mass. When the blending amount of the synthetic oil containing oxygen other than the alkyl diphenyl ether exceeds the above upper limit value, the lubricity, sealing property, refrigerant compatibility, thermal / chemical stability, electrical insulating property, etc. tend not to be satisfied in a well-balanced manner. is there.

  In the present invention, an alkyl diphenyl ether and a synthetic oil containing oxygen other than the alkyl diphenyl ether blended as necessary are mainly used as a base oil.

  The refrigerating machine oil and the working fluid composition for a refrigerating machine of the present invention can be suitably used even in a mode in which no additive is blended, but various additives described later can be blended as necessary. .

  The refrigerating machine oil and the working fluid composition for a refrigerating machine of the present invention are phosphoric acid ester, acidic phosphoric acid ester, amine salt of acidic phosphoric acid ester, chlorinated phosphorus, in order to further improve the wear resistance and load resistance. It can contain at least one phosphorus compound selected from the group consisting of acid esters and phosphites. These phosphorus compounds are esters of phosphoric acid or phosphorous acid with alkanols and polyether type alcohols or derivatives thereof.

  Specifically, the phosphate ester includes 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, trixylenyl phosphate, cresyl diphenyl phosphate, xyle Nildiphenyl phosphate and the like.

  Examples of acidic phosphate esters include monobutyl acid phosphate, monopentyl acid phosphate, monohexyl acid phosphate, monoheptyl acid phosphate, monooctyl acid phosphate, monononyl acid phosphate, monodecyl acid phosphate, monoundecyl acid phosphate, monododecyl Acid phosphate, monotridecyl acid phosphate, monotetradecyl acid phosphate, monopentadecyl acid phosphate, monohexadecyl acid phosphate, monoheptadecyl acid phosphate, monooctadecyl acid phosphate, monooleyl acid phosphate, dibutyl acid phosphate, dipentyl acid , Dihexyl reed Dophosphate, diheptyl acid phosphate, dioctyl acid phosphate, dinonyl acid phosphate, didecyl acid phosphate, diundecyl acid phosphate, didodecyl acid phosphate, ditridecyl acid phosphate, ditetradecyl acid phosphate, dipentadecyl acid, dipentadecyl acid Examples include hexadecyl acid phosphate, diheptadecyl acid phosphate, dioctadecyl acid phosphate, and dioleyl acid phosphate.

  Examples of the amine salt of acidic phosphate ester include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine. , Salts with amines such as dipentylamine, dihexylamine, diheptylamine, dioctylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, etc. .

  Examples of the chlorinated phosphate ester include tris-dichloropropyl phosphate, tris-chloroethyl phosphate, tris-chlorophenyl phosphate, and polyoxyalkylene bis [di (chloroalkyl)] phosphate.

  As phosphites, dibutyl phosphite, dipentyl phosphite, dihexyl phosphite, diheptyl phosphite, dioctyl phosphite, dinonyl phosphite, didecyl phosphite, diundecyl phosphite, didodecyl phosphite, dioleyl Phosphite, diphenyl phosphite, dicresyl phosphite, tributyl phosphite, tripentyl phosphite, trihexyl phosphite, triheptyl phosphite, trioctyl phosphite, trinonyl phosphite, tridecyl phosphite, triundecyl phosphite Phyto, tridodecyl phosphite, trioleyl phosphite, triphenyl phosphite, tricresyl phosphite and the like can be mentioned.

  These phosphorus compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

  When the refrigerating machine oil and the working fluid composition for a refrigerating machine of the present invention contain a phosphorus compound, the content is not particularly limited, but is preferably based on the total amount of refrigerating machine oil (based on the total amount of base oil and all blended additives). Is 0.01 to 5.0 mass%, more preferably 0.02 to 3.0 mass%.

  Moreover, the refrigerating machine oil and working fluid composition for refrigerating machine of the present invention have a phenyl glycidyl ether type epoxy compound, an alkyl glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, and an allyloxirane compound in order to further improve the stability thereof. , An alkyl oxirane compound, an alicyclic epoxy compound, an epoxidized fatty acid monoester, and an epoxidized vegetable oil can be contained.

  Specific examples of the phenyl glycidyl ether type epoxy compound include phenyl glycidyl ether and alkylphenyl glycidyl ether. As used herein, the alkylphenyl glycidyl ether includes those having 1 to 3 alkyl groups having 1 to 13 carbon atoms, and those having one alkyl group having 4 to 10 carbon atoms, such as n-butylphenyl glycidyl. Ether, i-butylphenyl glycidyl ether, sec-butylphenyl glycidyl ether, tert-butylphenyl glycidyl ether, pentylphenyl glycidyl ether, hexylphenyl glycidyl ether, heptylphenyl glycidyl ether, octylphenyl glycidyl ether, nonylphenyl glycidyl ether, decylphenyl A glycidyl ether etc. can be illustrated as a preferable thing.

  As the alkyl glycidyl ether type epoxy compound, specifically, decyl glycidyl ether, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, 2-ethylhexyl glycidyl ether, neopentyl glycol diglycidyl ether, Examples thereof include trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1,6-hexanediol diglycidyl ether, sorbitol polyglycidyl ether, polyalkylene glycol monoglycidyl ether, and polyalkylene glycol diglycidyl ether.

  Specific examples of the glycidyl ester type epoxy compound include phenyl glycidyl ester, alkyl glycidyl ester, alkenyl glycidyl ester, etc., and preferable ones are glycidyl-2,2-dimethyloctanoate, glycidyl benzoate, glycidyl acrylate. And glycidyl methacrylate.

  Specific examples of the allyloxirane compound include 1,2-epoxystyrene and alkyl-1,2-epoxystyrene.

  Specific examples of the alkyloxirane compound include 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-epoxyheptane, 1,2-epoxyoctane, 1,2- Epoxy nonane, 1,2-epoxydecane, 1,2-epoxyundecane, 1,2-epoxydodecane, 1,2-epoxytridecane, 1,2-epoxytetradecane, 1,2-epoxypentadecane, 1,2- Examples include epoxyhexadecane, 1,2-epoxyheptadecane, 1,1,2-epoxyoctadecane, 2-epoxynonadecane, 1,2-epoxyicosane and the like.

  Specific examples of the alicyclic epoxy compound include 1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and bis (3,4 -Epoxycyclohexylmethyl) adipate, exo-2,3-epoxynorbornane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 2- (7-oxabicyclo [4.1.0] hept-3- Yl) -spiro (1,3-dioxane-5,3 ′-[7] oxabicyclo [4.1.0] heptane, 4- (1′-methylepoxyethyl) -1,2-epoxy-2-methyl Examples include cyclohexane and 4-epoxyethyl-1,2-epoxycyclohexane.

  Specific examples of the epoxidized fatty acid monoester include esters of an epoxidized fatty acid having 12 to 20 carbon atoms with an alcohol or phenol having 1 to 8 carbon atoms or an alkylphenol. In particular, butyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl, phenyl and butylphenyl esters of epoxy stearate are preferably used.

  Specific examples of the epoxidized vegetable oil include epoxy compounds of vegetable oils such as soybean oil, linseed oil and cottonseed oil.

  Among these epoxy compounds, phenyl glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, alicyclic epoxy compounds and epoxidized fatty acid monoesters are preferred. Of these, phenyl glycidyl ether type epoxy compounds and glycidyl ester type epoxy compounds are more preferred, and phenyl glycidyl ether, butylphenyl glycidyl ether, alkyl glycidyl esters or mixtures thereof are particularly preferred.

  When the refrigerating machine oil and the working fluid composition for a refrigerating machine of the present invention contain the above epoxy compound, the content of the epoxy compound is not particularly limited, but is 0.1 to 5.0% by mass based on the total amount of the refrigerating machine oil. It is preferably 0.2 to 2.0% by mass. In addition, the said epoxy compound may be used individually by 1 type, and may use 2 or more types together.

  Of course, two or more of the above phosphorus compounds and epoxy compounds may be used in combination.

  Furthermore, in the refrigerating machine oil and the working fluid composition for the refrigerating machine of the present invention, a conventionally known refrigerating machine oil additive such as di-tert-butyl-p-cresol, Phenolic antioxidants such as bisphenol A, amine-based antioxidants such as phenyl-α-naphthylamine, N, N-di (2-naphthyl) -p-phenylenediamine, antiwear agents such as zinc dithiophosphate, Extreme pressure agents such as chlorinated paraffin and sulfur compounds, oily agents such as fatty acids, silicone-based antifoaming agents, metal deactivators such as benzotriazole, viscosity index improvers, pour point depressants, detergent dispersants, etc. These additives can be blended alone or in combination of several kinds.

  The total blending amount of these additives is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less based on the total amount of refrigerating machine oil (based on the total amount of base oil and all blending additives).

Kinematic viscosity of the refrigerating machine oil of the present invention is not particularly limited, preferably a kinematic viscosity at 40 ° C. is 3~100mm ² / s, more preferably 4~80mm ² / s, 5~70mm ² / More preferably, it is s.

  The refrigerating machine oil of the present invention is used together with an HFC refrigerant, and the working fluid composition for a refrigerating machine of the present invention contains an HFC refrigerant, but the refrigerant used in the present invention is an HFC refrigerant alone. Or a mixed refrigerant of an HFC refrigerant and another refrigerant. Examples of other refrigerants include fluorine-containing ether refrigerants such as bar fluoroethers, hydrocarbons, carbon dioxide, dimethyl ether, and ammonia.

  HFC refrigerants include specific hydrofluorocarbons having 1 to 3 carbon atoms, preferably 1 to 2 carbon atoms. Specifically, for example, difluoromethane (HFC-32), trifluoromethane (HFC-23), pentafluoroethane (HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134), 1, Examples thereof include HFCs such as 1,1,2-tetrafluoroethane (HFC-134a) and 1,1,1-trifluoroethane (HFC-143a), and mixtures of two or more thereof. These refrigerants are appropriately selected depending on the application and required performance. For example, HFC-32 alone; HFC-23 alone; HFC-134a alone; HFC-125 alone; HFC-134a / HFC-32 = 60 to 80 mass % / 40-20 mass% mixture; HFC-32 / HFC-125 = 40-70 mass% / 60-30 mass% mixture; HFC-125 / HFC-143a = 40-60 mass% / 60-40 mass % Mixture; HFC-134a / HFC-32 / HFC-125 = 60 wt% / 30 wt% / 10 wt% mixture; HFC-134a / HFC-32 / HFC-125 = 40-70 wt% / 15- 35 mass% / 5 to 40 mass% mixture; HFC-125 / HFC-134a / HFC-143a = 35-55 mass% / 1-15 mass% / 40-60 mass Such as a mixture of preferred examples include. More specifically, a mixture of HFC-134a / HFC-32 = 70/30 mass%; a mixture of HFC-32 / HFC-125 = 60/40 mass%; HFC-32 / HFC-125 = 50/50 mass % Mixture (R410A); HFC-32 / HFC-125 = 45/55 wt% mixture (R410B); HFC-125 / HFC-143a = 50/50 wt% mixture (R507C); HFC-32 / HFC -125 / HFC-134a = 30/10/60 wt% mixture; HFC-32 / HFC-125 / HFC-134a = 23/25/52 wt% mixture (R407C); HFC-32 / HFC-125 / HFC-134a = 25/15/60 mass% mixture (R407E); HFC-125 / HFC-134a / HFC-143a = Mixtures of 4/4/52 wt% (R404A), and the like.

  Specific examples of the fluorinated ether refrigerant include HFE-134p, HFE-245mc, HFE-236mf, HFE-236me, HFE-338mcf, HFE-365mc-f, HFE-245mf, HFE-347mmy, HFE-347mcc. , HFE-125, HFE-143m, HFE-134m, HFE-227me and the like.

  As the hydrocarbon refrigerant, a gas refrigerant at 25 ° C. and 1 atm is preferably used. Specifically, it is an alkane, cycloalkane, alkene or a mixture thereof having 1 to 5 carbon atoms, preferably 1 to 4 carbon atoms. Specific examples include methane, ethylene, ethane, propylene, propane, cyclopropane, butane, isobutane, cyclobutane, methylcyclopropane, or a mixture of two or more thereof. Among these, propane, butane, isobutane or a mixture thereof is preferable.

  The mixing ratio of the HFC refrigerant and carbon dioxide, fluorine-containing ether refrigerant, dimethyl ether, and ammonia is not particularly limited, but the total amount of the refrigerant used in combination with the HFC refrigerant is preferably 1 to 200 mass with respect to 100 parts by mass of HFC. Part, more preferably 10 to 100 parts by mass. As a preferred embodiment, the HFC refrigerant and carbon dioxide and / or hydrocarbon are preferably 1 to 200 parts by mass, more preferably 10 to 100 parts by mass as the total amount of carbon dioxide and hydrocarbons with respect to 100 parts by mass of HFC. The mixed refrigerant which mix | blended is mentioned.

  The refrigerating machine oil of the present invention is usually present in the form of a refrigerating machine fluid composition mixed with a refrigerant containing HFC as described above in refrigerating and air-conditioning equipment. The blending ratio of the refrigerating machine oil and the refrigerant in this composition is not particularly limited, but the refrigerating machine oil is preferably 1 to 500 parts by mass, more preferably 2 to 400 parts by mass with respect to 100 parts by mass of the refrigerant.

  The refrigerating machine oil and working fluid composition for the refrigerating machine of the present invention sufficiently satisfy all required performances such as lubricity, refrigerant compatibility, low temperature fluidity, stability, etc. in a well-balanced manner, reciprocating or rotating. It can be suitably used for refrigeration equipment or heat pumps having an open or hermetic compressor.

  More specifically, examples of the refrigeration equipment include automobile air conditioners, dehumidifiers, refrigerators, refrigerator / freezer warehouses, vending machines, showcases, cooling equipment for chemical plants, residential air conditioners, hot water supply heat pumps, and the like.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[ Examples 1-9 , Reference Examples 1-9 , Comparative Examples 1-10]
In Examples 1 to 9, Reference Examples 1 to 9, and Comparative Examples 1 to 10, refrigerating machine oil compositions having the compositions shown in Tables 1 to 4 were prepared using the base oils and additives shown below, respectively.
(Base oil)
Base oil 1: alkyl diphenyl ether 1 (kinematic viscosity at 40 ° C .: 15 mm ² / s, pour point: less than −40 ° C.)
Base oil 2: alkyl diphenyl ether 2 (kinematic viscosity at 40 ° C .: 32 mm ² / s, pour point: less than −40 ° C.)
Base oil 3: A mixture of base oil 1 (70 parts by mass) and base oil 6 (30 parts by mass) (kinematic viscosity at 40 ° C .: 21 mm ² / s, pour point: less than −40 ° C.)
Base oil 4: Mixture of base oil 1 (70 parts by mass) and base oil 7 (30 parts by mass) (kinematic viscosity at 40 ° C .: 22 mm ² / s, pour point: less than −40 ° C.)
Base oil 5: Mixture of base oil 1 (70 parts by mass) and base oil 8 (30 parts by mass) (kinematic viscosity at 40 ° C .: 22 mm ² / s, pour point: less than −40 ° C.)
Base oil 6: polyoxyalkylene glycol dialkyl ether (kinematic viscosity at 40 ° C. 50 mm ² / s, pour point: less than −40 ° C.)
Base oil 7: tetraester of mixed fatty acid of 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid and pentaerythritol (kinematic viscosity at 40 ° C. 68 mm ² / s, pour point: less than −40 ° C.)
Base oil 8: polyvinyl ether (kinematic viscosity at 40 ° C. 68 mm ² / s, pour point: less than −40 ° C.)
Base oil 9: branched alkylbenzene (kinematic viscosity at 40 ° C .: 32 mm ² / s, pour point: less than −40 ° C.).
(Additive)
Additive A1: tricresyl phosphate additive A2: glycidyl-2,2′-dimethyloctanoate additive A3: 1,2-epoxycyclohexane.

Next, the following evaluation was performed about each refrigeration oil composition of Examples 1-9, Reference Examples 1-9, and Comparative Examples 1-10.

[Refrigerant compatibility test]
In accordance with JIS K 2111, 19 g of HFC-134a and 1 g of sample oil were sealed in a glass tube, and at 0 ° C., it was observed whether the sample oil was dissolved or separated from each other.

[Lubricity test]
Using a rolling piston type compressor, filling each refrigerating machine oil 70g and the refrigerant (HFC-134a) 50g of Examples and Comparative Examples to the compressor discharge pressure 16 kgf / ^cm 2 G, the suction pressure 0 kgf / ^cm 2 G, the rotational speed The operation was performed for 1000 hours under conditions of 3000 rpm and a test temperature of 160 ° C., and the surface roughness Ra of the sliding surface of the vane of the compressor after the test was measured.

[Thermal stability test]
90 g of sample oil and 10 g of HFC-134a were sealed in an autoclave, a stability test was performed using iron, copper and aluminum as catalysts, and the acid value of the sample oil after being kept at 200 ° C. for 2 weeks was measured. In addition, all the initial acid values of each sample oil are 0.01 mgKOH / g or less.

[Electrical insulation test]
In accordance with JIS C2101, a direct current of 250 V / mm was applied to the sample oil at a sample temperature of 25 ° C., and the volume resistivity was determined from the current value after 1 minute.

Claims (4)

A base oil using an alkyl diphenyl ether alone or a base oil using an alkyl diphenyl ether and a synthetic oil containing oxygen (excluding polyalkylene glycol) in combination, and the blending amount of the synthetic oil containing oxygen is the alkyl A refrigerating machine oil comprising a base oil that is 100 parts by mass or less with respect to 100 parts by mass of diphenyl ether and a phosphate ester, and is used together with a hydrofluorocarbon refrigerant.   The refrigerating machine oil according to claim 1, wherein the hydrofluorocarbon refrigerant is HFC-134a, R407C, R404A or R410A. A base oil using an alkyl diphenyl ether alone or a base oil using an alkyl diphenyl ether and a synthetic oil containing oxygen (excluding polyalkylene glycol) in combination, and the blending amount of the synthetic oil containing oxygen is the alkyl A working fluid composition for a refrigerator , comprising a base oil of 100 parts by mass or less with respect to 100 parts by mass of diphenyl ether , a phosphate ester, and a hydrofluorocarbon refrigerant.   The working fluid composition for a refrigerator according to claim 3, wherein the hydrofluorocarbon refrigerant is HFC-134a, R407C, R404A or R410A.