JP2018016736A - Refrigeration machine oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration machine oil that has an excellent wear resistance even when the added amount of anti-wear agent is small.SOLUTION: Provided is a refrigeration machine oil containing a lubricating base oil and diphenyl hydrogen phosphite.SELECTED DRAWING: None

Description

  The present invention relates to refrigerating machine oil.

  Refrigerators such as refrigerators, car air conditioners, room air conditioners, and vending machines include a compressor for circulating the refrigerant in the refrigeration cycle. The compressor is filled with refrigerating machine oil for lubricating the sliding member. Generally, refrigerating machine oil contains a base oil and additives blended according to desired properties.

  As the additive, for example, an anti-wear agent added to improve the wear resistance of the refrigerating machine oil is known. Examples of the antiwear agent include phosphorus additives. Patent Document 1 discloses a refrigerating machine oil containing a phosphorus-based additive composed of phosphoric acid triester and / or phosphorous acid triester.

JP 2008-266423 A

  By the way, from the viewpoint of reducing the manufacturing cost of refrigerating machine oil, it is required to reduce the amount of additive used as much as possible. In addition, the phosphorus additive improves the wear resistance of the refrigeration oil, but may adversely affect the stability. From the viewpoint of ensuring the stability of the refrigeration oil, the addition amount of the phosphorus additive is Less is desirable.

  However, the phosphoric acid triester or phosphorous acid triester used in the refrigerator oil described in Patent Document 1 is not necessarily sufficient in terms of the effect of improving the wear resistance per unit amount.

  Accordingly, an object of the present invention is to provide a refrigerating machine oil that is excellent in wear resistance even when the addition amount of the antiwear agent is small.

  The present inventors solved the above problems by using an antiwear agent having a high effect of improving wear resistance per unit amount. That is, this invention provides the refrigerating machine oil containing lubricating base oil and diphenyl hydrogen phosphite.

  The content of diphenyl hydrogen phosphite is preferably 0.005 to 1% by mass based on the total amount of refrigerating machine oil.

  The content of diphenyl hydrogen phosphite is preferably 0.01 to 0.3% by mass based on the total amount of refrigerating machine oil.

  The refrigerating machine oil preferably further contains an epoxy compound. In this case, a refrigerating machine oil having excellent load resistance and stability in addition to wear resistance can be obtained. In addition, this refrigerating machine oil is less likely to cause problems in terms of compatibility with resin materials.

  The content of the epoxy compound is preferably 0.1 to 4% by mass based on the total amount of refrigerating machine oil.

  The refrigerating machine oil preferably contains at least one selected from the group consisting of a glycidyl ester type epoxy compound and a glycidyl ether type epoxy compound as an epoxy compound.

  The refrigerating machine oil preferably contains 0.01 to 2% by mass of a glycidyl ester type epoxy compound as an epoxy compound based on the total amount of the refrigerating machine oil.

  The refrigerating machine oil preferably contains 0.01 to 2% by mass of a glycidyl ether type epoxy compound as an epoxy compound based on the total amount of the refrigerating machine oil.

  The mass ratio of the epoxy compound content to the diphenyl hydrogen phosphite content is preferably 0.1 or more.

  According to the refrigerating machine oil of the present invention, excellent wear resistance can be obtained even when the addition amount of the antiwear agent is small.

  The refrigerating machine oil according to the present embodiment contains a lubricating oil base oil and diphenyl hydrogen phosphite.

  As the lubricating base oil, hydrocarbon oil, oxygen-containing oil and the like can be used. Examples of the hydrocarbon oil include mineral oil-based hydrocarbon oil and synthetic hydrocarbon oil. Examples of the oxygen-containing oil include esters, ethers, carbonates, ketones, silicones, and polysiloxanes.

  Mineral oil-based hydrocarbon oils are obtained by removing solvent oil from solvent oil fractions obtained by atmospheric distillation and vacuum distillation of paraffinic and naphthenic crude oil, solvent refining, hydrorefining, hydrocracking, solvent dewatering. It can be obtained by purification by a method such as wax, hydrodewaxing, clay treatment, or sulfuric acid washing. These purification methods may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the synthetic hydrocarbon oil include alkylbenzene, alkylnaphthalene, poly α-olefin (PAO), polybutene, and ethylene-α-olefin copolymer.

As the alkylbenzene, the following alkylbenzene (A) and / or alkylbenzene (B) can be used.
Alkylbenzene (A): an alkylbenzene having 1 to 4 alkyl groups having 1 to 19 carbon atoms and having a total carbon number of 9 to 19 (preferably 1 to 1 alkyl group having 1 to 15 carbon atoms). -4 alkylbenzenes having a total carbon number of 9-15 alkyl groups)
Alkylbenzene (B): an alkylbenzene having 1 to 4 alkyl groups having 1 to 40 carbon atoms and having a total carbon number of 20 to 40 (preferably 1 to 1 alkyl group having 1 to 30 carbon atoms). -4 alkylbenzenes having a total carbon number of the alkyl group of 20-30)

  Specific examples of the alkyl group having 1 to 19 carbon atoms that the alkylbenzene (A) has include, for example, a methyl group, an ethyl group, a propyl group (including all isomers, the same applies hereinafter), a butyl group, a pentyl group, and a hexyl group. Group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group. These alkyl groups may be linear or branched, and are preferably branched from the viewpoints of stability and viscosity characteristics. In particular, branched alkyl groups derived from oligomers of olefins such as propylene, butene and isobutylene are more preferred from the viewpoint of availability.

  The number of alkyl groups in the alkylbenzene (A) is 1 to 4, and preferably 1 or 2 (that is, monoalkylbenzene, dialkylbenzene, or a mixture thereof) from the viewpoint of stability and availability. is there.

  The alkylbenzene (A) may contain only a single structure alkylbenzene, has 1 to 4 alkyl groups having 1 to 19 carbon atoms, and has a total carbon number of 9 to 19 alkyl groups. If it is the alkylbenzene which satisfy | fills conditions, the mixture of the alkylbenzene which has a different structure may be contained.

  Specific examples of the alkyl group having 1 to 40 carbon atoms that the alkylbenzene (B) has include, for example, a methyl group, an ethyl group, a propyl group (including all isomers, the same applies hereinafter), a butyl group, a pentyl group, and a hexyl group. Group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group, Tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group, triacontyl group, hentriacontyl group, dotriacontyl group, tritriacontyl group, tetratriacontyl group, pentatriacontyl group, hexa Triacontyl group, f Tatoriakonchiru group, octamethylene triacontyl group, nona triacontyl group, and a tetracontyl group. These alkyl groups may be linear or branched, and are preferably branched from the viewpoints of stability and viscosity characteristics. In particular, branched alkyl groups derived from oligomers of olefins such as propylene, butene and isobutylene are more preferred from the viewpoint of availability.

  The number of alkyl groups in the alkylbenzene (B) is 1 to 4, and preferably 1 or 2 (that is, monoalkylbenzene, dialkylbenzene, or a mixture thereof) from the viewpoint of stability and availability. is there.

  The alkylbenzene (B) may contain only a single structure alkylbenzene, has 1 to 4 alkyl groups having 1 to 40 carbon atoms, and the total carbon number of the alkyl groups is 20 to 40. If it is the alkylbenzene which satisfy | fills conditions, the mixture of the alkylbenzene which has a different structure may be contained.

  The poly α-olefin (PAO) is a compound obtained by polymerizing several molecules of a straight chain olefin having 6 to 18 carbon atoms having a double bond only at one end and then hydrogenating the polymer. The poly α-olefin may be, for example, isoparaffin having a molecular weight distribution centered on a trimer or tetramer of α-decene having 10 carbon atoms or α-dodecene having 12 carbon atoms.

  Examples of the ester include aromatic esters, dibasic acid esters, polyol esters, complex esters, carbonate esters, and mixtures thereof. As the ester, a polyol ester or a complex ester is preferable.

  The polyol ester is an ester of a polyhydric alcohol and a fatty acid. A saturated fatty acid is preferably used as the fatty acid. The number of carbon atoms of the fatty acid is preferably 4 to 20, more preferably 4 to 18, still more preferably 4 to 9, and particularly preferably 5 to 9. The polyol ester may be a partial ester in which some of the hydroxyl groups of the polyhydric alcohol are not esterified and remain as hydroxyl groups, or may be a complete ester in which all of the hydroxyl groups are esterified. It may be a mixture of an ester and a complete ester. The hydroxyl value of the polyol ester is preferably 10 mgKOH / g or less, more preferably 5 mgKOH / g or less, still more preferably 3 mgKOH / g or less.

  Of the fatty acids constituting the polyol ester, the proportion of fatty acids having 4 to 20 carbon atoms is preferably 20 to 100 mol%, more preferably 50 to 100 mol%, and 70 to 100 mol%. Is more preferable, and 90 to 100 mol% is particularly preferable.

  Specific examples of fatty acids having 4 to 20 carbon atoms include butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, and pentadecanoic acid. Hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid and icosanoic acid. These fatty acids may be linear or branched. More specifically, fatty acids having a branch at the α-position and / or β-position are preferred, and 2-methylpropanoic acid, 2-methylbutanoic acid, 2-methylpentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-methylheptanoic acid, 2-ethylhexanoic acid, 3,5,5-trimethylhexanoic acid, 2-ethylhexadecanoic acid and the like are more preferable, among which 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid are more preferable. preferable.

  The fatty acid may contain fatty acids other than fatty acids having 4 to 20 carbon atoms. As fatty acids other than fatty acids having 4 to 20 carbon atoms, for example, fatty acids having 21 to 24 carbon atoms may be used. Specific examples include helicoic acid, docosanoic acid, tricosanoic acid, and tetracosanoic acid. These fatty acids may be linear or branched.

  As the polyhydric alcohol constituting the polyol ester, a polyhydric alcohol having 2 to 6 hydroxyl groups is preferably used. As carbon number of a polyhydric alcohol, 4-12 are preferable and 5-10 are more preferable. Specifically, hindered alcohols such as neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), pentaerythritol, and dipentaerythritol are preferable. . Pentaerythritol or a mixed ester of pentaerythritol and dipentaerythritol) is more preferred because it is particularly excellent in compatibility with the refrigerant and hydrolytic stability.

The complex ester is an ester synthesized by the following method (a) or (b), for example.
(A) Adjusting the molar ratio of the polyhydric alcohol and the polybasic acid to synthesize an ester intermediate in which a part of the carboxyl group of the polybasic acid remains unesterified, and then the remaining carboxyl group Method of esterifying with monohydric alcohol (b) Adjusting the molar ratio between the polyhydric alcohol and the polybasic acid to synthesize an ester intermediate in which a part of the hydroxyl groups of the polyhydric alcohol remain unesterified, Next, a method of esterifying the remaining hydroxyl group with a monovalent fatty acid

  The complex ester obtained by the method (b) is slightly inferior in stability to the complex ester obtained by the method (a) because a relatively strong acid is generated when hydrolyzed during use as a refrigerating machine oil. There is a tendency. As the complex ester in the present embodiment, a complex ester obtained by the method (a) having higher stability is preferable.

  The complex ester is preferably at least one selected from polyhydric alcohols having 2 to 4 hydroxyl groups, at least one selected from polybasic acids having 6 to 12 carbon atoms, and 4 to 18 carbon atoms. It is an ester synthesized from at least one selected from monohydric alcohols and monovalent fatty acids having 2 to 12 carbon atoms.

  Examples of the polyhydric alcohol having 2 to 4 hydroxyl groups include neopentyl glycol, trimethylolpropane and pentaerythritol. As polyhydric alcohols having 2 to 4 hydroxyl groups, neopentyl glycol and trimethylolpropane are used from the viewpoint of securing a suitable viscosity when a complex ester is used as a base oil and obtaining good low-temperature characteristics. Preferably, neopentyl glycol is more preferable from the viewpoint that viscosity can be widely adjusted.

  From the viewpoint of excellent lubricity, the polyhydric alcohol constituting the complex ester further contains a dihydric alcohol having 2 to 10 carbon atoms other than neopentyl glycol in addition to the polyhydric alcohol having 2 to 4 hydroxyl groups. It is preferable to do. Examples of the dihydric alcohol having 2 to 10 carbon atoms other than neopentyl glycol include ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, 2-methyl-1,3-propanediol, and 3-methyl-1,5. -Pentanediol, 2,2-diethyl-1,3-pentanediol and the like. Among these, butanediol is preferable from the viewpoint of excellent properties of the lubricating base oil. Examples of butanediol include 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, and the like. Among these, 1,3-butanediol and 1,4-butanediol are more preferable from the viewpoint of obtaining good characteristics. The amount of the dihydric alcohol having 2 to 10 carbon atoms other than neopentyl glycol is preferably 1.2 mol or less with respect to 1 mol of the polyhydric alcohol having 2 to 4 hydroxyl groups, 0.8 The amount is more preferably less than or equal to mol, and still more preferably less than or equal to 0.4 mol.

  Examples of the polybasic acid having 6 to 12 carbon atoms include adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, and trimellitic acid. Among these, adipic acid and sebacic acid are preferable and adipic acid is more preferable from the viewpoint of excellent balance of properties of the synthesized ester and easy availability. The amount of the polybasic acid having 6 to 12 carbon atoms is preferably 0.4 mol to 4 mol with respect to 1 mol of the polyhydric alcohol having 2 to 4 hydroxyl groups, and 0.5 mol to 3 mol. More preferably, the molar ratio is 0.6 mol to 2.5 mol.

  Examples of the monohydric alcohol having 4 to 18 carbon atoms include aliphatic alcohols such as butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, dodecanol, and oleyl alcohol. These monohydric alcohols may be linear or branched. The monohydric alcohol having 4 to 18 carbon atoms is preferably a monohydric alcohol having 6 to 10 carbon atoms, and more preferably a monohydric alcohol having 8 to 10 carbon atoms, from the viewpoint of balance of characteristics. Among these, 2-ethylhexanol and 3,5,5-trimethylhexanol are more preferable from the viewpoint of improving the low-temperature characteristics of the synthesized complex ester.

  Examples of the monovalent fatty acid having 2 to 12 carbon atoms include ethanoic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, and dodecanoic acid. These monovalent fatty acids may be linear or branched. The monovalent fatty acid having 2 to 12 carbon atoms is preferably a monovalent fatty acid having 8 to 10 carbon atoms, and among these, 2-ethylhexanoic acid and 3,5,5-trimethyl are more preferable from the viewpoint of low temperature characteristics. Hexanoic acid.

  Examples of ethers include polyvinyl ether, polyalkylene glycol, polyphenyl ether, perfluoroether, and mixtures thereof. As the ether, polyvinyl ether or polyalkylene glycol is preferable, and polyvinyl ether is more preferable.

［式（１）中、Ｒ^１、Ｒ^２及びＲ^３は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭化水素基を表し、Ｒ^４は二価の炭化水素基又は二価のエーテル結合酸素含有炭化水素基を表し、Ｒ^５は炭化水素基を表し、ｍは０以上の整数を表す。ｍが２以上である場合には、複数のＲ^４は互いに同一でも異なっていてもよい。］ Polyvinyl ether has a structural unit represented by the following formula (1).

[In the formula (1), R ¹ , R ² and R ³ may be the same or different from each other and each represents a hydrogen atom or a hydrocarbon group, and R ⁴ is a divalent hydrocarbon group or a divalent ether bond. Represents an oxygen-containing hydrocarbon group, R ⁵ represents a hydrocarbon group, and m represents an integer of 0 or more. When m is 2 or more, the plurality of R ⁴ may be the same as or different from each other. ]

The number of carbon atoms of the hydrocarbon group represented by R ¹ , R ² and R ³ is preferably 1 or more, more preferably 2 or more, still more preferably 3 or more, and preferably 8 or less, more preferably 7 Hereinafter, it is more preferably 6 or less. Preferably R ^1, at least one of ^{R 2} and ^{R 3} is a hydrogen ^atom, more preferably all of R 1, ^{R 2} and ^{R 3} are hydrogen atoms.

The carbon number of the divalent hydrocarbon group represented by R ⁴ and the ether-bonded oxygen-containing hydrocarbon group is preferably 1 or more, more preferably 2 or more, still more preferably 3 or more, and preferably 10 or less. More preferably, it is 8 or less, More preferably, it is 6 or less. The divalent ether bond oxygen-containing hydrocarbon group represented by R ⁴ may be, for example, a hydrocarbon group having oxygen in the side chain to form an ether bond.

R ⁵ is preferably a hydrocarbon group having 1 to 20 carbon atoms. Examples of the hydrocarbon group include an alkyl group, a cycloalkyl group, a phenyl group, an aryl group, and an arylalkyl group. Among these, an alkyl group is preferable, and an alkyl group having 1 to 5 carbon atoms is more preferable.

  m is preferably 0 or more, more preferably 1 or more, still more preferably 2 or more, and is preferably 20 or less, more preferably 18 or less, and still more preferably 16 or less. The average value of m in all structural units constituting the polyvinyl ether is preferably 0-10.

  The polyvinyl ether may be a homopolymer composed of one type selected from the structural unit represented by the formula (1), or composed of two or more types selected from the structural unit represented by the formula (1). The copolymer may be a copolymer composed of the structural unit represented by the formula (1) and another structural unit. When polyvinyl ether is a copolymer, lubricity, insulating properties, hygroscopicity, and the like can be further improved while satisfying compatibility with the refrigerant of the refrigerating machine oil. At this time, the various characteristics of the refrigerating machine oil can be made desired by appropriately selecting the kind of raw material monomer, the kind of initiator, the ratio of structural units in the copolymer, and the like. The copolymer may be either a block copolymer or a random copolymer.

When polyvinyl ether is a copolymer, the copolymer is represented by the above formula (1) and R ⁵ is an alkyl group having 1 to 3 carbon atoms, and the above formula ( It is preferable to have a structural unit (1-2) represented by 1) and wherein R ⁵ is an alkyl group having 3 to 20, preferably 3 to 10, more preferably 3 to 8 carbon atoms. As R ⁵ in the structural unit (1-1), an ethyl group is particularly preferable, and as R ⁵ in the structural unit (1-2), an isobutyl group is particularly preferable. When polyvinyl ether is a copolymer having the above structural units (1-1) and (1-2), the molar ratio of the structural unit (1-1) to the structural unit (1-2) is 5: It is preferably 95 to 95: 5, more preferably 20:80 to 90:10, and still more preferably 70:30 to 90:10. When the molar ratio is within the above range, the compatibility with the refrigerant can be further improved, and the hygroscopicity tends to be lowered.

［式（２）中、Ｒ^６〜Ｒ^９は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜２０の炭化水素基を表す。］ The polyvinyl ether may be composed only of the structural unit represented by the above formula (1), but may be a copolymer further having a structural unit represented by the following formula (2). . In this case, the copolymer may be a block copolymer or a random copolymer.

[In Formula (2), R < ⁶ > -R < ⁹ > may mutually be same or different, and represents a hydrogen atom or a C1-C20 hydrocarbon group, respectively. ]

  The polyvinyl ether is represented by the polymerization of a vinyl ether monomer corresponding to the structural unit represented by the formula (1), or the vinyl ether monomer corresponding to the structural unit represented by the formula (1) and the formula (2). It can be produced by copolymerization with a hydrocarbon monomer having an olefinic double bond corresponding to the structural unit. As the vinyl ether monomer corresponding to the structural unit represented by the formula (1), a monomer represented by the following formula (3) is suitable.

［式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びｍは、それぞれ式（１）中のＲ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びｍと同一の定義内容を示す。］

^{Wherein, R 1, R 2, R} 3, R 4, R 5 and m ^{is, R 1, R 2, R} 3, R 4, R 5 and the same definition and m, respectively formula (1) Indicates. ]

The polyvinyl ether preferably has the following terminal structure (A) or (B).
(A) A structure in which one end is represented by formula (4) or (5) and the other end is represented by formula (6) or (7).

［式（４）中、Ｒ^１１、Ｒ^２１及びＲ^３１は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜８の炭化水素基を示し、Ｒ^４１は炭素数１〜１０の二価の炭化水素基又は二価のエーテル結合酸素含有炭化水素基を示し、Ｒ^５１は炭素数１〜２０の炭化水素基を示し、ｍは式（１）中のｍと同一の定義内容を示す。ｍが２以上の場合には、複数のＲ^４１は互いに同一でも異なっていてもよい。］

[In the formula (4), R ¹¹ , R ²¹ and R ³¹ may be the same or different from each other, and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and R ⁴¹ has 1 to 10 carbon atoms. A divalent hydrocarbon group or a divalent ether-bonded oxygen-containing hydrocarbon group, R ⁵¹ represents a hydrocarbon group having 1 to 20 carbon atoms, and m represents the same definition as m in formula (1). Show. When m is 2 or more, the plurality of R ⁴¹ may be the same as or different from each other. ]

［式（５）中、Ｒ^６１、Ｒ^７１、Ｒ^８１及びＲ^９１は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜２０の炭化水素基を示す。］

[In Formula (5), R ⁶¹ , R ⁷¹ , R ⁸¹ and R ⁹¹ may be the same or different from each other, and each represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. ]

［式（６）中、Ｒ^１２，Ｒ^２２及びＲ^３２は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜８の炭化水素基を示し、Ｒ^４２は炭素数１〜１０の二価の炭化水素基又は二価のエーテル結合酸素含有炭化水素基を示し、Ｒ^５２は炭素数１〜２０の炭化水素基を示し、ｍは式（１）中のｍと同一の定義内容を示す。ｍが２以上の場合には、複数のＲ^４１は同一でも異なっていてもよい。］

[In the formula (6), R ¹² , R ²² and R ³² may be the same or different from each other, and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and R ⁴² has 1 to 10 carbon atoms. A divalent hydrocarbon group or a divalent ether-bonded oxygen-containing hydrocarbon group, R ⁵² represents a hydrocarbon group having 1 to 20 carbon atoms, and m represents the same definition as m in formula (1). Show. When m is 2 or more, the plurality of R ⁴¹ may be the same or different. ]

［式（７）中、Ｒ^６２、Ｒ^７２、Ｒ^８２及びＲ^９２は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜２０の炭化水素基を示す。］

[In Formula (7), R ⁶² , R ⁷² , R ⁸² and R ⁹² may be the same as or different from each other, and each represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. ]

［式（８）中、Ｒ^１３、Ｒ^２３及びＲ^３３は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜８の炭化水素基を示す。］ (B) A structure in which one end is represented by the above formula (4) or (5) and the other end is represented by the following formula (8).

[In Formula (8), R < ¹³ >, R < ²³ > and R ^<33 > may mutually be same or different, and show a hydrogen atom or a C1-C8 hydrocarbon group, respectively. ]

Among such polyvinyl ethers, the following polyvinyl ethers (a), (b), (c), (d) and (e) are particularly suitable as the base oil.
(A) one end is represented by formula (4) or (5) and the other end is represented by formula (6) or (7), and R ¹ and R in formula (1) ² and R ³ are both hydrogen atoms, m is an integer of 0 to 4, R ⁴ is a divalent hydrocarbon group having 2 to ⁴ carbon atoms, and R ⁵ is a hydrocarbon group having 1 to 20 carbon atoms. .
(B) It has only the structural unit represented by Formula (1), Comprising: One terminal is represented by Formula (4), and the other terminal has a structure represented by Formula (6). In Formula (1), R ¹ , R ² and R ³ are all hydrogen atoms, m is an integer of 0 to 4, R ⁴ is a divalent hydrocarbon group having 2 to ⁴ carbon atoms, and R ⁵ is carbon number 1 Polyvinyl ether which is ˜20 hydrocarbon groups.
(C) One end is represented by formula (4) or (5) and the other end is represented by formula (8), and R ¹ , R ² and R ³ in formula (1) Are all hydrogen atoms, m is an integer of 0 to 4, R ⁴ is a divalent hydrocarbon group having 2 to ⁴ carbon atoms, and R ⁵ is a hydrocarbon group having 1 to 20 carbon atoms.
(D) It has only the structural unit represented by Formula (1), and has one end represented by Formula (5) and the other end represented by Formula (8). In Formula (1), R ¹ , R ² and R ³ are all hydrogen atoms, m is an integer of 0 to 4, R ⁴ is a divalent hydrocarbon group having 2 to ⁴ carbon atoms, and R ⁵ is carbon number 1 Polyvinyl ether which is ˜20 hydrocarbon groups.
(E) any one of the above (a), (b), (c) and (d), wherein R ⁵ in the formula (1) is a hydrocarbon group having 1 to 3 carbon atoms and the R ⁵ is a polyvinyl ether having a structural unit in which ⁵ is a hydrocarbon group having 3 to 20 carbon atoms.

  The degree of unsaturation of polyvinyl ether is preferably 0.04 meq / g or less, more preferably 0.03 meq / g or less, and still more preferably 0.02 meq / g or less. The peroxide value of polyvinyl ether is preferably 10.0 meq / kg or less, more preferably 5.0 meq / kg or less, and even more preferably 1.0 meq / kg. The carbonyl value of polyvinyl ether is preferably 100 ppm by weight or less, more preferably 50 ppm by weight or less, and still more preferably 20 ppm by weight or less. The hydroxyl value of polyvinyl ether is preferably 10 mgKOH / g or less, more preferably 5 mgKOH / g or less, and still more preferably 3 mgKOH / g or less.

  In the present invention, the degree of unsaturation, the peroxide value, and the carbonyl value are values measured by the standard oil analysis method established by the Japan Oil Chemists' Society. That is, the degree of unsaturation in the present invention is determined by reacting a sample with a Wis solution (ICl-acetic acid solution) and leaving it in the dark, then reducing excess ICl to iodine and titrating the iodine content with sodium thiosulfate. The iodine value is calculated, and the iodine value is converted to a vinyl equivalent (meq / g). The peroxide value in the present invention is a value (meq / kg) obtained by adding potassium iodide to a sample, titrating the resulting free iodine with sodium thiosulfate, and converting this free iodine to the number of milliequivalents per 1 kg of the sample. Say. The carbonyl value in the present invention is a calibration curve obtained by allowing 2,4-dinitrophenylhydrazine to act on a sample to produce a chromogenic quinoid ion, measuring the absorbance of this sample at 480 nm, and using cinnamaldehyde as a standard substance in advance. The value (weight ppm) converted into the amount of carbonyl based on the above. The hydroxyl value in the present invention means a hydroxyl value measured according to JIS K0070: 1992.

  Examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, polybutylene glycol and the like. Polyalkylene glycol has oxyethylene, oxypropylene, oxybutylene or the like as a structural unit. Polyalkylene glycols having these structural units can be obtained by ring-opening polymerization using monomers ethylene oxide, propylene oxide, and butylene oxide as raw materials.

  Examples of the polyalkylene glycol include a compound represented by the following formula (9).

^{R α - [(OR β)} f -OR γ] g (9)
[In formula (9), R ^α represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, or a residue of a compound having 2 to 8 hydroxyl groups, and R ^β represents carbon. R 2 represents an alkylene group having 2 to 4, R ^γ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an acyl group having 2 to 10 carbon atoms, f represents an integer of 1 to 80, and g represents 1 to Represents an integer of 8. ]

The alkyl group represented by R ^α and R ^γ may be linear, branched or cyclic. Carbon number of the alkyl group is preferably 1-10, more preferably 1-6. When the number of carbon atoms in the alkyl group exceeds 10, the compatibility with the refrigerant tends to decrease.

The alkyl group part of the acyl group represented by R ^α and R ^γ may be linear, branched or cyclic. Carbon number of an acyl group becomes like this. Preferably it is 2-10, More preferably, it is 2-6. If the number of carbon atoms in the acyl group exceeds 10, the compatibility with the refrigerant may be reduced and phase separation may occur.

When the groups represented by R ^α and R ^γ are both alkyl groups or are both acyl groups, the groups represented by R ^α and R ^γ may be the same or different. When g is 2 or more, a plurality of groups represented by R ^α and R ^γ in the same molecule may be the same or different.

When the group represented by R ^alpha is a residue of a compound having 2-8 hydroxyl groups, the compound may be cyclic be a chain.

At least one of R ^α and R ^γ is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and still more preferably a methyl group, from the viewpoint of excellent compatibility. From the viewpoint of excellent thermal and chemical stability, both R ^α and R ^γ are preferably alkyl groups, more preferably alkyl groups having 1 to 4 carbon atoms, and still more preferably methyl groups. From the viewpoint of ease of production and cost, it is preferable that either one of R ^α and R ^γ is an alkyl group (more preferably an alkyl group having 1 to 4 carbon atoms), and the other is a hydrogen atom. More preferably, it is a methyl group and the other is a hydrogen atom. From the viewpoint of excellent lubricity and sludge solubility, both R ^α and R ^γ are preferably hydrogen atoms.

R ^beta represents an alkylene group having 2 to 4 carbon atoms, examples of such alkylene groups include ethylene, propylene, butylene, and the like. Moreover, examples of the oxyalkylene group of the repeating unit represented by OR ^β include an oxyethylene group, an oxypropylene group, and an oxybutylene group. Oxyalkylene group represented by (OR ^β) _f may consist of one oxyalkylene group, or may be composed of two or more oxyalkylene groups.

  Among the polyalkylene glycols represented by the formula (9), a copolymer containing an oxyethylene group (EO) and an oxypropylene group (PO) is used from the viewpoint of excellent compatibility with a refrigerant and viscosity-temperature characteristics. preferable. In this case, the ratio (EO / (PO + EO)) of the oxyethylene group in the total of the oxyethylene group and the oxypropylene group is 0.1 to 0.8 from the viewpoint of excellent baking load and viscosity-temperature characteristics. Is more preferable, and 0.3 to 0.6 is more preferable. From the viewpoint of excellent hygroscopicity and heat / oxidation stability, EO / (PO + EO) is preferably 0 to 0.5, more preferably 0 to 0.2, and 0 (that is, propylene oxide alone). Most preferably, it is a polymer).

f represents the repeating number (polymerization degree) of the oxyalkylene group OR ^β and is an integer of 1 to 80. g is an integer of 1-8. For example, when R ^α is an alkyl group or an acyl group, g is 1. If R ^alpha is a residue of a compound having 2-8 hydroxyl groups, g is the number of hydroxyl groups the compound has.

  In the polyalkylene glycol represented by the formula (9), the average value of the product of f and g (f × g) is preferably 6 to 80 from the viewpoint of satisfying the required performance as a refrigerating machine oil in a balanced manner. .

  The number average molecular weight of the polyalkylene glycol represented by the formula (9) is preferably 500 or more, more preferably 600 or more, preferably 3000 or less, more preferably 2000 or less, and further preferably 1500 or less. . f and g are preferably numbers such that the number average molecular weight of the polyalkylene glycol satisfies the above conditions. When the number average molecular weight of the polyalkylene glycol is too small, the lubricity in the presence of the refrigerant may be insufficient. When the number average molecular weight is too large, the composition range showing compatibility with the refrigerant under low temperature conditions is narrowed, and the lubrication failure of the refrigerant compressor and the heat exchange in the evaporator are liable to occur.

  The hydroxyl value of the polyalkylene glycol is preferably 100 mgKOH / g or less, more preferably 50 mgKOH / g or less, still more preferably 30 mgKOH / g or less, and most preferably 10 mgKOH / g or less.

Polyalkylene glycol can be synthesized using a known method ("alkylene oxide polymer", Mitsuta Shibata et al., Kaibundo, issued on November 20, 1990). For example, an alcohol ^(R α OH; R α formula (9) R ^alpha and represent the same definition in) etherified or esterified into by addition polymerization of one or more predetermined alkylene oxide, further terminal hydroxyl groups By doing this, the polyalkylene glycol represented by Formula (9) is obtained. When two or more alkylene oxides are used in the above production process, the resulting polyalkylene glycol may be either a random copolymer or a block copolymer, but tends to be more excellent in oxidation stability and lubricity. In view of the above, a block copolymer is preferable, and a random copolymer is preferable from the viewpoint of excellent low-temperature fluidity.

  The degree of unsaturation of the polyalkylene glycol is preferably 0.04 meq / g or less, more preferably 0.03 meq / g or less, and most preferably 0.02 meq / g or less. The peroxide value is preferably 10.0 meq / kg or less, more preferably 5.0 meq / kg or less, and most preferably 1.0 meq / kg. The carbonyl value is preferably 100 ppm by weight or less, more preferably 50 ppm by weight or less, and most preferably 20 ppm by weight or less.

Kinematic viscosity at 40 ° C. of the lubricating base oil is preferably ^{3 mm} 2 / s or more, more preferably ^{4 mm} 2 / s or more, may be even more preferably at ^{5 mm} 2 / s or more. Kinematic viscosity at 40 ° C. of the lubricating base oil is preferably 1000 mm ² / s or less, more preferably 500 mm ² / s or less, more preferably may be at 400 mm ² / s or less. The kinematic viscosity at 100 ° C. of the lubricating base oil may be preferably 1 mm ² / s or more, more preferably 2 mm ² / s or more. The kinematic viscosity at 100 ° C. of the lubricating base oil may be preferably 100 mm ² / s or less, more preferably 50 mm ² / s or less. The kinematic viscosity in the present invention means a kinematic viscosity measured according to JIS K2283: 2000.

  The content of the lubricating base oil may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more based on the total amount of the refrigerating machine oil.

The diphenyl hydrogen phosphite may be, for example, at least one of a compound represented by the following formula (b-1) and a compound represented by the following formula (b-2) which is a tautomer thereof.

  The content of diphenyl hydrogen phosphite (including the tautomer thereof, the same shall apply hereinafter) in the present embodiment is preferably 0.005 to 1% by mass, more preferably 0.01 to 0%, based on the total amount of refrigerating machine oil. 0.5% by mass, more preferably 0.01-0.3% by mass, still more preferably 0.05-0.3% by mass, particularly preferably 0.1-0.25% by mass.

  As long as the diphenyl hydrogen phosphite in the present embodiment is contained in the refrigerating machine oil of the present embodiment, its purity is not particularly limited, and it is desirable to use a pure product, but it is not necessarily used for reasons such as a manufacturing process or a purification cost. It is not necessary to use a pure product. The purity of diphenyl hydrogen phosphite blended in the refrigerating machine oil of the present embodiment is preferably 50 mol% or more, more preferably 70 mol% or more. Diphenyl hydrogen phosphite may be used as an additive containing diphenyl hydrogen phosphite as a main component.

  The acid value of diphenyl hydrogen phosphite in the present embodiment is about 240 mgKOH / g in a pure product, and may not necessarily be used as a pure product due to reasons such as manufacturing process, purification cost, dilution, etc., but preferably 100 mgKOH / g or more, more preferably 150 mgKOH / g or more, still more preferably 170 mgKOH / g or more. The closer the acid value is to 240 mgKOH / g, the higher the effect of improving the wear resistance per unit addition amount. In addition, the acid value here means the acid value measured based on JIS K 2501 "Petroleum products and lubricating oil-neutralization number test method".

  The refrigerating machine oil preferably further contains an epoxy compound (also referred to as “epoxy acid scavenger”). When the refrigerating machine oil contains diphenyl hydrogen phosphite and an epoxy compound, the load resistance can be improved as compared with, for example, a case of containing phosphoric acid triester or phosphorous acid triester and an epoxy compound.

  Examples of the epoxy compound include glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, oxirane compounds, alkyl oxirane compounds, alicyclic epoxy compounds, epoxidized fatty acid monoesters, and epoxidized vegetable oils. These epoxy compounds can be used individually by 1 type or in combination of 2 or more types.

［式（Ｃ−１）中、Ｒ^ａはアリール基又は炭素数５〜１８のアルキル基を示す。］ As the glycidyl ether type epoxy compound, for example, an aryl glycidyl ether type epoxy compound or an alkyl glycidyl ether type epoxy compound represented by the following formula (C-1) can be used.

[In Formula (C-1), R ^a represents an aryl group or an alkyl group having 5 to 18 carbon atoms. ]

  Examples of the glycidyl ether type epoxy compound represented by the formula (C-1) include n-butylphenyl glycidyl ether, i-butylphenyl glycidyl ether, sec-butylphenyl glycidyl ether, tert-butylphenyl glycidyl ether, pentylphenyl glycidyl ether. Hexyl phenyl glycidyl ether, heptyl phenyl glycidyl ether, octyl phenyl glycidyl ether, nonyl phenyl glycidyl ether, decyl phenyl glycidyl ether, decyl glycidyl ether, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, 2 -Ethylhexyl glycidyl ether is preferred.

When the carbon number of the alkyl group represented by ^Ra is 5 or more, the stability of the epoxy compound is ensured, and the epoxy compound is decomposed before reacting with moisture, fatty acid, oxidatively deteriorated product, or the epoxy compounds are polymerized with each other. The occurrence of polymerization can be suppressed, and the intended function can be easily obtained. On the other hand, when the carbon number of the alkyl group represented by ^Ra is 18 or less, the solubility with the refrigerant is kept good, and it is possible to make it difficult to cause problems such as poor cooling due to precipitation in the refrigeration apparatus. .

  As the glycidyl ether type epoxy compound, in addition to the epoxy compound represented by the formula (C-1), neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1,6-hexanediol diglycidyl Ether, sorbitol polyglycidyl ether, polyalkylene glycol monoglycidyl ether, polyalkylene glycol diglycidyl ether and the like can also be used.

［式（Ｃ−２）中、Ｒ^ｂはアリール基、炭素数５〜１８のアルキル基、又はアルケニル基を示す。］ As the glycidyl ester type epoxy compound, for example, one represented by the following formula (C-2) can be used.

[In the formula (C-2), R ^b represents an aryl group, an alkyl group having 5 to 18 carbon atoms, or an alkenyl group. ]

  As the glycidyl ester type epoxy compound represented by the formula (C-2), glycidyl benzoate, glycidyl neodecanoate, glycidyl-2,2-dimethyloctanoate, glycidyl acrylate and glycidyl methacrylate are preferable.

When the carbon number of the alkyl group represented by ^Rb is 5 or more, the stability of the epoxy compound is ensured, and the epoxy compound decomposes before reacting with moisture, fatty acid, oxidatively deteriorated product, or the epoxy compound is polymerized. The occurrence of polymerization can be suppressed, and the intended function can be easily obtained. On the other hand, when the carbon number of the alkyl group or alkenyl group represented by ^Rb is 18 or less, the solubility with the refrigerant is kept good, and it is difficult to cause problems such as poor cooling due to precipitation in the refrigerator. Can do.

An alicyclic epoxy compound is a compound having a partial structure represented by the following general formula (C-3), in which carbon atoms constituting an epoxy group directly constitute an alicyclic ring.

  Examples of the alicyclic epoxy compound include 1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 3 ′, 4′-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 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-methylcyclohexane 4-epoxyethyl-1,2-epoxycyclohexane is preferred.

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

  Examples of the alkyloxirane compounds include 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-epoxyheptane, 1,2-epoxyoctane, 1,2-epoxynonane, 1, 2-epoxydecane, 1,2-epoxyundecane, 1,2-epoxydodecane, 1,2-epoxytridecane, 1,2-epoxytetradecane, 1,2-epoxypentadecane, 1,2-epoxyhexadecane, 1, Examples include 2-epoxyheptadecane, 1,2-epoxyoctadecane, 1,2-epoxynonadecane, and 1,2-epoxyicosane.

  Examples of the epoxidized fatty acid monoester include esters of epoxidized fatty acids having 12 to 20 carbon atoms and alcohols having 1 to 8 carbon atoms, phenol or alkylphenol. As the epoxidized fatty acid monoester, butyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl, phenyl and butylphenyl esters of epoxy stearate are preferably used.

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

  The epoxy compound is preferably at least one selected from a glycidyl ester type epoxy compound and a glycidyl ether type epoxy compound, from the viewpoint of excellent compatibility with a resin material (for example, nylon) used for a member in a refrigerator. Preferably, it is at least one selected from glycidyl ester type epoxy compounds.

  The content of the epoxy compound is preferably 0.1 to 4% by mass, more preferably 0.2 to 2% by mass, still more preferably 0.4 to 1.5% by mass, and particularly preferably based on the total amount of refrigerating machine oil. 0.4 to 1.2% by mass.

  When the refrigerating machine oil contains a glycidyl ester type epoxy compound as an epoxy compound, the content of the glycidyl ester type epoxy compound is preferably 0.01 to 2% by mass, more preferably 0.1 to 2%, based on the total amount of the refrigerating machine oil. The mass% is more preferably 0.2 to 1.5 mass%, still more preferably 0.4 to 1.2 mass%, and particularly preferably 0.5 to 0.9 mass%.

  When the refrigerating machine oil contains a glycidyl ether type epoxy compound as an epoxy compound, the content of the glycidyl ether type epoxy compound is preferably 0.01 to 2% by mass, more preferably 0.1 to 2%, based on the total amount of the refrigerating machine oil. The mass% is more preferably 0.2 to 1.5 mass%, still more preferably 0.4 to 1.2 mass%, and particularly preferably 0.5 to 0.9 mass%.

  When the refrigerating machine oil contains an epoxy compound, the mass ratio of the epoxy compound content to the diphenyl hydrogen phosphite content (epoxy compound content / diphenyl hydrogen phosphite content) is preferably 0.1. As mentioned above, More preferably, it is 0.5 or more, More preferably, it is 1 or more, Preferably it is 30 or less, More preferably, it is 10 or less, More preferably, it is 5 or less.

  The refrigerating machine oil may further contain an antioxidant. Antioxidants are, for example, di-tert. It may be a phenolic antioxidant such as butyl-p-cresol. The content of the antioxidant is, for example, 0.01% by mass or more and 5% by mass or less based on the total amount of the refrigerating machine oil.

  The refrigerating machine oil may further contain a phosphorus-based antiwear agent other than diphenyl hydrogen phosphite. Such phosphorus-based antiwear agents are, for example, phosphate esters such as triphenyl phosphate (TPP) and tricresyl phosphate (TCP), and thiophosphate esters such as triphenyl phosphorothioate (TPPT). Good. The content of the phosphorus-based anti-wear antioxidant other than diphenyl hydrogen phosphite is, for example, 0.01% by mass or more and 5% by mass or less based on the total amount of the refrigerating machine oil.

  The refrigerating machine oil may further contain other additives in addition to the components described above. Examples of other additives include acid scavengers other than epoxy compounds, extreme pressure agents, oiliness agents, antifoaming agents, metal deactivators, antiwear agents other than phosphorus antiwear agents, viscosity index improvers, Pour point depressants, cleaning dispersants and the like can be mentioned. The content of these additives is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total amount of refrigerating machine oil.

Kinematic viscosity at 40 ° C. of the refrigerating machine oil is preferably ^{3 mm} 2 / s or more, more preferably ^{4 mm} 2 / s or more, may be even more preferably at ^{5 mm} 2 / s or more. Kinematic viscosity at 40 ° C. of the refrigerating machine oil is preferably 500 mm ² / s or less, more preferably 400 mm ² / s or less, more preferably may be less 300 mm ² / s. The kinematic viscosity at 100 ° C. of the refrigerating machine oil may be preferably 1 mm ² / s or more, more preferably 2 mm ² / s or more. The kinematic viscosity at 100 ° C. of the refrigerating machine oil may be preferably 100 mm ² / s or less, more preferably 50 mm ² / s or less. The kinematic viscosity in the present invention means a kinematic viscosity measured according to JIS K2283: 2000.

  The pour point of the refrigerating machine oil may be preferably −10 ° C. or lower, more preferably −20 ° C. or lower. The pour point in the present invention means a pour point measured according to JIS K2269: 1987.

The volume resistivity of the refrigerating machine oil is preferably 1.0 × 10 ⁹ Ω · m or more, more preferably 1.0 × 10 ¹⁰ Ω · m or more, and further preferably 1.0 × 10 ¹¹ Ω · m or more. It's okay. The volume resistivity in the present invention means a volume resistivity at 25 ° C. measured according to JIS C2101: 1999.

  The water content of the refrigeration oil is preferably 200 ppm or less, more preferably 100 ppm or less, and even more preferably 50 ppm or less, based on the total amount of the refrigeration oil.

  The acid value of the refrigerating machine oil is preferably 1.0 mgKOH / g or less, more preferably 0.1 mgKOH / g or less. The acid value in the present invention means an acid value measured according to JIS K2501: 2003.

  The ash content of the refrigerating machine oil may be preferably 100 ppm or less, more preferably 50 ppm or less. The ash content in this invention means the ash content measured based on JISK2272: 1998.

  The refrigerating machine oil according to the present embodiment is usually present as a working fluid composition for a refrigerating machine mixed with a refrigerant in the refrigerating machine. That is, the refrigerating machine oil according to this embodiment is used together with a refrigerant, and the refrigerating machine working fluid composition according to this embodiment contains the refrigerating machine oil and the refrigerant according to this embodiment.

  Such refrigerants include saturated fluorinated hydrocarbon refrigerants, unsaturated fluorinated hydrocarbon refrigerants, hydrocarbon refrigerants, fluorinated ether refrigerants such as perfluoroethers, bis (trifluoromethyl) sulfide refrigerants, and trifluoroiodinated. Examples include methane refrigerant and natural refrigerants such as ammonia and carbon dioxide.

  The saturated fluorinated hydrocarbon refrigerant is preferably a saturated fluorinated hydrocarbon having 1 to 3 carbon atoms, more preferably 1 to 2 carbon atoms. Specifically, difluoromethane (R32), trifluoromethane (R23), pentafluoroethane (R125), 1,1,2,2-tetrafluoroethane (R134), 1,1,1,2-tetrafluoroethane (R134a), 1,1,1-trifluoroethane (R143a), 1,1-difluoroethane (R152a), fluoroethane (R161), 1,1,1,2,3,3,3-heptafluoropropane ( R227ea), 1,1,1,2,3,3-hexafluoropropane (R236ea), 1,1,1,3,3,3-hexafluoropropane (R236fa), 1,1,1,3,3 -Pentafluoropropane (R245fa) and 1,1,1,3,3-pentafluorobutane (R365mfc), or a mixture of two or more of these Thing, and the like.

  The saturated fluorinated hydrocarbon refrigerant is appropriately selected from the above depending on the application and required performance. For example, R32 alone; R23 alone; R134a alone; R125 alone; R134a / R32 = 60 to 80% by mass / 40 R32 / R125 = 40-70 mass% / 60-30 mass% mixture; R125 / R143a = 40-60 mass% / 60-40 mass% mixture; R134a / R32 / R125 = 60 Mixture of mass% / 30 mass% / 10 mass%; R134a / R32 / R125 = 40-70 mass% / 15-35 mass% / 5-40 mass% mixture; R125 / R134a / R143a = 35-55 mass% Preferred examples include / 1-15% by mass / 40-60% by mass. More specifically, a mixture of R134a / R32 = 70/30% by mass; a mixture of R32 / R125 = 60/40% by mass; a mixture of R32 / R125 = 50/50% by mass (R410A); R32 / R125 = 45 / 55 wt% mixture (R410B); R125 / R143a = 50/50 wt% mixture (R507C); R32 / R125 / R134a = 30/10/60 wt% mixture; R32 / R125 / R134a = 23/25 / 52 mass% mixture (R407C); R32 / R125 / R134a = 25/15/60 mass% mixture (R407E); R125 / R134a / R143a = 44/4/52 mass% mixture (R404A), etc. be able to.

  The unsaturated fluorinated hydrocarbon (HFO) refrigerant is preferably fluoropropene, more preferably fluoropropene having 3 to 5 fluorine atoms. Specific examples of the unsaturated fluorinated hydrocarbon refrigerant include 1,2,3,3,3-pentafluoropropene (HFO-1225ye) and 1,3,3,3-tetrafluoropropene (HFO-1234ze). 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,2,3,3-tetrafluoropropene (HFO-1234ye), and 3,3,3-trifluoropropene (HFO-1243zf) It is preferable that they are any 1 type or a mixture of 2 or more types. From the viewpoint of the physical properties of the refrigerant, one or more selected from HFO-1225ye, HFO-1234ze, and HFO-1234yf are preferable.

  The hydrocarbon refrigerant 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, cyclobutane, methylcyclopropane, 2-methylbutane, normal pentane, or two or more of these. Of the mixture. Among these, gas at 25 ° C. and 1 atm is preferably used, and propane, normal butane, isobutane, 2-methylbutane or a mixture thereof is preferable.

  The content of the refrigerating machine oil in the working fluid composition for a refrigerating machine 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 the working fluid composition for the refrigerating machine according to the present embodiment include an air conditioner having a reciprocating or rotating hermetic compressor, a refrigerator, an open type or a sealed car air conditioner, a dehumidifier, a water heater, and a freezer. It is suitably used for refrigerators such as refrigerators, refrigerators, vending machines, showcases, chemical plants, refrigerators having a centrifugal compressor, and the like.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to an Example.

（エポキシ化合物）
Ｃ１：２−エチルヘキシルグリシジルエーテル
Ｃ２：グリシジルネオデカノエート
（その他の添加剤）
Ｄ１：トリフェニルホスファイト
Ｄ２：トリオクチルホスファイト
Ｄ３：トリフェニルホスフェート
Ｅ１：フェノール系酸化防止剤、アミン系酸化防止剤及び金属不活性化剤を含む添加剤 Refrigerating machine oil having the composition shown in Tables 1 to 3 (mass% based on the total quantity of refrigerating machine oil) was prepared using the base oil and additives shown below.
(Base oil)
A1: Polyol ester of pentaerythritol and 2-methylpropanoic acid / 3,5,5-trimethylhexanoic acid mixed fatty acid (mixing ratio 40/60) (40 ° C. kinematic viscosity: 68 mm ² / s, 100 ° C. kinematic viscosity) : 8.1 mm ² / s)
A2: Polyol ester of pentaerythritol / dipentaerythritol mixed alcohol (mixing ratio 75/25) and 2-ethylhexanoic acid / 3,5,5-trimethylhexanoic acid mixed fatty acid (mixing ratio 50/50) (40 ° C. kinematic viscosity: 90 mm ² / s, 100 ° C. kinematic viscosity: 10 mm ² / s)
(Diphenyl hydrogen phosphite)
B1: Diphenyl hydrogen phosphite (including a compound represented by the following formula (b-1) or a compound represented by the following formula (b-2) which is a tautomer thereof. Acid value: 200 mgKOH / g)

(Epoxy compound)
C1: 2-ethylhexyl glycidyl ether C2: glycidyl neodecanoate (other additives)
D1: Triphenyl phosphite D2: Trioctyl phosphite D3: Triphenyl phosphate E1: Additive containing phenolic antioxidant, amine antioxidant and metal deactivator

  About each refrigerating machine oil of Examples 1-2 and Comparative Examples 1-6, abrasion resistance was evaluated in the procedure shown below. The results are shown in Table 1.

(Abrasion resistance)
The FALEEX Pin / Vee-Block test was performed. Rotating speed: 290 rpm, temperature: 27 ± 2 ° C, oil amount: 120 mL, running in for 5 minutes under a load of 250 lb while blowing R32 refrigerant into the oil at 10 L / h, then load Was increased to 300 lb and this operation was performed for 60 minutes. The amount of wear at this time was measured. The results are shown in Table 1.

Moreover, the abrasion resistance improvement effect X per unit phosphorus amount in the refrigerator oil was calculated according to the following formula. The amount of phosphorus in the refrigeration oil was measured according to JPI-5S-38-2003. The results are shown in Table 1.
X = (W0−W1) / W0 / P
However, W0 is the amount of wear in Comparative Example 6 (7.2 mg), W1 is the amount of wear in each Example or Comparative Example (mg), and P is the amount of phosphorus in the refrigerating machine oil in each Example or Comparative Example (mass%) Respectively.

  About each refrigeration oil of Examples 3-7 and Comparative Examples 7-9, load resistance was evaluated in the procedure shown below. The results are shown in Table 2.

(Load resistance)
The FALEEX Pin / Vee-Block test was performed. Running-in operation under a load of 150 lb while blowing HFO-1234yf refrigerant at 10 L / h under conditions of rotation speed: 290 rpm, temperature: 27 ± 2 ° C., oil amount: 120 mL at room temperature (about 25 ° C.) Then, the load was applied, and the load when seizure occurred was defined as the seizure load. In addition, the ASTM standard piece was used as a test piece.

  About each refrigeration oil of Example 3, 5, 7-9, the stability in the presence of a refrigerant | coolant was evaluated in the procedure shown below. The results are shown in Table 3.

(Stability)
Refrigerating machine oil 30 g adjusted to a water content of 1000 ppm, HFO-1234yf refrigerant 30 g and Al, Cu, Fe catalysts (φ1.6 mm × 50 mm) were sealed in a 200 ml autoclave, and held in a constant temperature bath at 175 ° C. for 336 hours. After storing, the hue, acid value and amount of impurities of the refrigerating machine oil after the autoclave test were measured.

  About each refrigeration oil of Example 3, 9, and 10, material compatibility was evaluated in the procedure shown below. The results are shown in Table 4.

(Material compatibility)
60 g of refrigerating machine oil adjusted to a water content of less than 30 ppm, 60 g of HFO-1234yf refrigerant, and 10 mm × 75 mm nylon resin cut into a dumbbell shape were sealed in a 200 ml autoclave and kept in a constant temperature bath at 120 ° C. for 168 hours. Stored. Nylon resin taken out after autoclave test and nylon resin of the same shape not subjected to autoclave test were measured for tensile strength and tensile elongation in a tensile test according to JIS K6251, and changes in tensile strength defined by the following formula Rate and tensile elongation change rate were calculated.
Tensile strength change rate (%) = [(tensile strength of nylon resin after autoclave test) / (tensile strength of nylon resin not subjected to autoclave test) -1] × 100
Tensile elongation change rate (%) = [(elongation of nylon resin after autoclave test) / (elongation of nylon resin not subjected to autoclave test) -1] × 100

  By increasing the C1 component, the tensile strength tends to be slightly reduced, and by replacing the C1 component with the C2 component, the tensile strength and tensile elongation tend to be increased. That is, the tensile strength and the tensile elongation show a preferable tendency by using the C2 component.

Claims (9)

  A refrigerating machine oil containing a lubricating base oil and diphenyl hydrogen phosphite.   The refrigerating machine oil according to claim 1, wherein the content of the diphenyl hydrogen phosphite is 0.005 to 1% by mass based on the total amount of the refrigerating machine oil.   The refrigerating machine oil according to claim 1, wherein the content of the diphenyl hydrogen phosphite is 0.01 to 0.3 mass% based on the total amount of the refrigerating machine oil.   The refrigerating machine oil according to any one of claims 1 to 3, further comprising an epoxy compound.   The refrigerating machine oil according to claim 4, wherein the content of the epoxy compound is 0.1 to 4% by mass based on the total amount of the refrigerating machine oil.   The refrigerating machine oil according to claim 4 or 5, comprising at least one selected from the group consisting of a glycidyl ester type epoxy compound and a glycidyl ether type epoxy compound as the epoxy compound.   The refrigerating machine oil according to any one of claims 4 to 6, comprising 0.01 to 2% by mass of a glycidyl ester type epoxy compound based on the total amount of the refrigerating machine oil as the epoxy compound.   The refrigerating machine oil according to any one of claims 4 to 7, comprising 0.01 to 2% by mass of a glycidyl ether type epoxy compound as a total amount of refrigerating machine oil as the epoxy compound.   Refrigerating machine oil as described in any one of Claims 4-8 whose mass ratio of content of the said epoxy compound with respect to content of the said diphenyl hydrogen phosphite is 0.1 or more.