JP5143461B2 - Refrigerating machine oil for carbon dioxide refrigerant and working fluid composition for refrigerator. - Google Patents

Description

  The present invention relates to a refrigerating machine oil for carbon dioxide refrigerant and a working fluid composition for a refrigerating machine.

  Due to the problem of ozone depletion in recent years, CFC (chlorofluorocarbon) and HCFC (hydrochlorofluorocarbon), which have been used as refrigerants for refrigeration equipment, are subject to regulation, and HFC (hydrofluorocarbon) as a refrigerant instead. It is being used. However, such HFC refrigerants also have problems such as a high global warming potential (GWP). Therefore, the use of natural refrigerants such as carbon dioxide, ammonia, and hydrocarbons with low GWP is being studied as an alternative refrigerant to replace these fluorocarbon refrigerants.

Among them, carbon dioxide (CO ₂ ) is harmless to the environment and is excellent in terms of safety, and since it has been used as a refrigerant for refrigerators although it was not mainstream so far, Its application is being studied as a refrigerant for car air conditioners, room air conditioners, or hot water supply heat pumps using open compressors or hermetic electric compressors.

Under such circumstances, the development of refrigerant oil for alternative refrigerants has been promoted, and the use of various refrigerant oils has been proposed. For example, as a refrigerating machine oil for a carbon dioxide refrigerant, Patent Document 1 uses a hydrocarbon base oil, and Patent Document 2 uses an ether base oil such as polyalkylene glycol (PAG) or polyvinyl ether (PVE). Patent Document 3 discloses an aromatic polyether oil, and Patent Documents 4 to 6 disclose an ester base oil.
Japanese Patent Laid-Open No. 10-46168 Japanese Patent Laid-Open No. 10-46169 JP 2000-73951 A JP 2000-104084 A JP 2000-169868 A JP 2000-169869 A

  However, it has been found that the use of the above conventional refrigeration oil in the presence of carbon dioxide refrigerant greatly shortens the life of the rolling bearing of the compressor.

  The present invention has been made in view of the above-described problems of the prior art, and in the presence of a carbon dioxide refrigerant, a refrigerating machine oil that can sufficiently prevent a reduction in the life of a rolling bearing of a compressor, and its It aims at providing the working fluid composition for refrigerators using refrigerator oil.

In order to solve the above problems, the present invention contains an alkyl ether, kinematic viscosity at 40 ° C. is 3~500mm ² / s, formulated in 2-400 parts by weight per 100 parts by weight refrigerant Rukoto A refrigerating machine oil for carbon dioxide refrigerant is provided.

Moreover, this invention contains the refrigerating machine oil which contains alkyl diphenyl ether and whose kinematic viscosity in 40 degreeC is 3-500 mm < ² > / s, and a carbon dioxide refrigerant | coolant, 2-400 mass of refrigerant | coolants with respect to 100 mass parts of refrigerant | coolants. formulated in part to provide a working fluid composition for a refrigerating machine characterized by Rukoto.

  According to the refrigerating machine oil for carbon dioxide refrigerant and the working fluid composition for refrigerating machine of the present invention, it is possible to sufficiently prevent the life of the rolling bearing of the compressor from being lowered in the presence of the carbon dioxide refrigerant.

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

  The refrigerating machine oil for carbon dioxide refrigerant of the present invention contains alkyl diphenyl ether. The working fluid composition for a refrigerator of the present invention contains alkyl diphenyl ether and a carbon dioxide refrigerant. The working fluid composition for a refrigerator of the present invention includes an embodiment containing the refrigerant oil for carbon dioxide refrigerant of the present invention and a carbon dioxide refrigerant.

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. It is preferable that kinematic 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.

It is preferable that kinematic 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 carbon dioxide refrigerant of the present invention, the alkyl diphenyl ether compound may be used mainly as a base oil, or may be used by blending with another 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 refrigeration oil for carbon dioxide refrigerant and the working fluid composition for refrigeration according to 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 alkyl diphenyl ether is 100 masses. The synthetic oil containing oxygen is preferably 900 parts by mass or less and more preferably 800 parts by mass or less with respect to parts.

  When the blending amount of the synthetic oil containing oxygen other than the alkyl diphenyl ether exceeds the upper limit, the life extension of the rolling bearing tends to be not satisfied.

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 for carbon dioxide refrigerant and the working fluid composition for refrigerating machine of the present invention can be suitably used even in an embodiment in which no additive is blended, but if necessary, various additives described later are blended. You can also

  The refrigerating machine oil for carbon dioxide refrigerant and the working fluid composition for refrigerating machine of the present invention are phosphoric acid ester, acidic phosphoric acid ester, and amine salt of acidic phosphoric acid ester in order to further improve the wear resistance and load resistance. , At least one phosphorus compound selected from the group consisting of chlorinated phosphates and phosphites can be blended. 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 for carbon dioxide refrigerant and the working fluid composition for refrigerating machine of the present invention contain a phosphorus compound, the content is not particularly limited, but is based on the total amount of refrigerating machine oil (based on the total amount of base oil and all blended additives) ), Preferably 0.01 to 5.0 mass%, more preferably 0.02 to 3.0 mass%.

  The refrigeration oil for carbon dioxide refrigerant and the working fluid composition for refrigeration according to the present invention include a phenyl glycidyl ether type epoxy compound, an alkyl glycidyl ether type epoxy compound, and a glycidyl ester type epoxy compound in order to further improve the stability. , An allyl oxirane compound, 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 for carbon dioxide refrigerant and the working fluid composition for refrigerating machine of the present invention contain the epoxy compound, the content of the epoxy compound is not particularly limited, but is 0.1 to 5.0 based on the total amount of the refrigerating machine oil. It is preferable that it is mass%, and it is more preferable that it is 0.2-2.0 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 order to further improve the performance of the refrigerating machine oil for carbon dioxide refrigerant and the working fluid composition for refrigerating machine of the present invention, a conventionally known refrigerating machine oil additive such as di-tert-butyl is used as necessary. -Phenol-based antioxidants such as p-cresol and bisphenol A, amine-based antioxidants such as phenyl-α-naphthylamine and N, N-di (2-naphthyl) -p-phenylenediamine, zinc dithiophosphate, etc. Anti-wear agents, extreme pressure agents such as chlorinated paraffin and sulfur compounds, oily agents such as fatty acids, antifoaming agents such as silicones, metal deactivators such as benzotriazole, viscosity index improvers, pour point depressants It is also possible to add additives such as a cleaning dispersant 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).

Although the kinematic viscosity of the carbon dioxide refrigerant refrigerating machine oil of the present invention is not particularly limited, preferably a kinematic viscosity at 40 ° C. is 3~500mm ² / s, more preferably 4~400mm ² / s, 5 More preferably, it is ˜300 mm ² / s.

It is preferable that kinematic viscosity at 100 ° C. for carbon dioxide refrigerant refrigerating machine oil of the present invention is 1 to 50 mm ² / s, more preferably 1.5~40mm ² / s, 2~30mm ² / More preferably, it is s.

  When the kinematic viscosity of the refrigerating machine oil is within the above range, lubricity, sealing properties, refrigerant compatibility, and the like tend to be satisfied in a more balanced manner.

  The refrigerating machine oil for carbon dioxide refrigerant of the present invention having the above-described configuration is used as a fluid composition mixed with carbon dioxide refrigerant in the refrigerant circulation system of the refrigeration equipment. That is, the fluid composition for a refrigerator of the present invention contains the above-described refrigerator oil for a carbon dioxide refrigerant of the present invention and a carbon dioxide refrigerant.

  Here, the mixing ratio of the refrigerating machine oil and the refrigerant in the refrigerating machine fluid composition of the present invention is not particularly limited, but the refrigerating machine oil is preferably 1 to 500 parts by mass, more preferably 2 to 2 parts by mass with respect to 100 parts by mass of the refrigerant. 400 parts by mass.

  The fluid composition for a refrigerator according to the present invention contains a carbon dioxide refrigerant as described above, but may further contain other refrigerants such as hydrofluorocarbon (HFC), hydrocarbon, and ammonia. .

  Examples of the hydrofluorocarbon refrigerant according to the present invention include 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, 1,1,2-tetrafluoroethane (HFC-134a), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), or a mixture of two or more thereof Is mentioned.

  Moreover, as a hydrocarbon refrigerant | coolant concerning this invention, a gaseous thing is preferably used at 25 degreeC and 1 atmosphere. 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 of two or more thereof is preferable.

  The mixing ratio of carbon dioxide and hydrofluorocarbon and / or hydrocarbon is not particularly limited, but is preferably 1 to 100 parts by mass as the total amount of hydrofluorocarbon and hydrocarbon with respect to 100 parts by mass of carbon dioxide. Preferably it is 10-80 mass parts.

  The carbon dioxide refrigerant refrigerating machine oil and the working fluid composition for refrigerating machine of the present invention satisfy all required performances such as lubricity, refrigerant compatibility, low-temperature fluidity, and stability in a well-balanced and reciprocating manner. It can be suitably used for a refrigeration apparatus or a heat pump having an open or closed compressor of the type or rotation type. More specifically, an air conditioner for a car, a dehumidifier, a refrigerator, a refrigerator / freezer warehouse, a vending machine, a showcase, a cooling device for a chemical plant, an air conditioner for a house, a heat pump for hot water supply, 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 to 5 and Comparative Examples 1 to 4] In Examples 1 to 5 and Comparative Examples 1 to 4, refrigerator oil compositions having the compositions shown in Table 1 using the base oils and additives shown below, respectively. Was prepared.
(Base oil)
Base oil 1: alkyl diphenyl ether 1 (kinematic viscosity at 40 ° C .: 68 mm ² / s, pour point: less than −40 ° C.)
Base oil 2: alkyl diphenyl ether 2 (kinematic viscosity at 40 ° C .: 100 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 .: 63 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 .: 68 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 .: 68 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.).

  Next, the following evaluation was performed about each refrigeration oil composition of Examples 1-5 and Comparative Examples 1-4.

[Rolling bearing characteristics evaluation test]
First, the refrigerant atmosphere friction test apparatus used in this test will be described. The refrigerant atmosphere friction test apparatus includes a friction tester housed in a pressure vessel, and a friction test can be performed in a refrigerant atmosphere by introducing a refrigerant into the pressure vessel. More specifically, a bearing provided with a roller and a plate (both made by SUJ2) as an upper test piece and a plate (made by SUJ2) as a lower test piece are stacked in a pressure vessel. It is arranged so as to be immersed in the sample oil. Then, a predetermined load is applied from the lower test piece to the upper test piece, and the upper test piece bearing is rotated by a predetermined rotation so that the lower surface of the upper plate and the upper surface of the lower plate are given a predetermined load. It is possible to rub under. A vibration meter is attached to the support of the lower test piece, and if vibration due to pitching occurs when the test piece is rubbed, the vibration can be detected.

  In this test, the pressure of the carbon dioxide refrigerant was 3 MPa, the temperature was 80 ° C., the bearing rotation speed was 1800 rpm, the load applied to the lower plate was 4 kN, and the time (min) until vibration due to pitching was detected was measured. . This test was performed three times and the average value was obtained. The obtained results are shown in Table 1.

Claims (2)

Containing alkyl ether, kinematic viscosity at 40 ℃ is 3~500mm ² / s, carbon dioxide refrigerant refrigerating machine oil, characterized in Rukoto formulated in 2-400 parts by weight per 100 parts by weight refrigerant. Containing alkyl ether, kinematic viscosity at 40 ° C. is contained and refrigerating machine oil is 3~500mm ² / s, and a carbon dioxide refrigerant, Rukoto be formulated in a refrigerant 2 to 400 parts by weight per 100 parts by weight refrigerant A working fluid composition for a refrigerator.