JP2018048223A - Refrigerator oil and working fluid composition for refrigerators - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerator oil having excellent seizure resistance and a working fluid composition for refrigerators.SOLUTION: A refrigerator oil contains a lubricant base oil, and a compound represented by the following formula (A). [In formula (A), Rand Rindependently represent a monovalent hydrocarbon group, Ris a divalent hydrocarbon group, X is a polar group containing a -COORgroup. Ris a hydrogen atom or a monovalent hydrocarbon group].SELECTED DRAWING: None

Description

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

  Refrigerators such as refrigerators and air conditioners include a compressor for circulating the refrigerant in the refrigerant circulation system. The compressor is filled with refrigerating machine oil to lubricate the sliding member. Refrigerating machine oil is required to have characteristics such as lubricity and compatibility with refrigerants.

  Refrigerating machine oil generally contains an additive selected according to such required characteristics. For example, phosphorus additives are known as additives that improve lubricity (particularly wear resistance). Patent Document 1 discloses a lubricating oil composition for a refrigerator containing a phosphorus-based additive composed of a phosphate triester such as tricresyl phosphate and triphenyl phosphate.

JP 2008-266423 A

  However, refrigerating machine oils containing phosphorus additives such as tricresyl phosphate as disclosed in Patent Document 1 still have room for improvement in terms of lubricity (particularly seizure resistance).

  In view of such circumstances, the present inventors have focused on improving seizure resistance and developed refrigerating machine oil. That is, an object of the present invention is to provide a refrigerating machine oil and a working fluid composition for a refrigerating machine that are excellent in seizure resistance.

［式（Ａ）中、Ｒ^１及びＲ^２はそれぞれ独立に１価の炭化水素基を表し、Ｒ^３は２価の炭化水素基を表し、Ｘは−ＣＯＯＲ^４基を含む極性基を表す。Ｒ^４は水素原子又は１価の炭化水素基を表す。］ The present invention provides a refrigerating machine oil containing a lubricating base oil and a compound represented by the following formula (A).

[In Formula (A), R ¹ and R ² each independently represent a monovalent hydrocarbon group, R ³ represents a divalent hydrocarbon group, and X represents a polar group containing a —COOR ⁴ group. R ⁴ represents a hydrogen atom or a monovalent hydrocarbon group. ]

  The present invention also provides a working fluid composition for a refrigerating machine containing the refrigerating machine oil and a refrigerant.

  ADVANTAGE OF THE INVENTION According to this invention, the working fluid composition for refrigerator oil and refrigerator which is excellent in seizure resistance can be provided.

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

［式（Ａ）中、Ｒ^１及びＲ^２はそれぞれ独立に１価の炭化水素基を表し、Ｒ^３は２価の炭化水素基を表し、Ｘは−ＣＯＯＲ^４基を含む極性基を表す。Ｒ^４は水素原子又は１価の炭化水素基を表す。］ The refrigerating machine oil contains a lubricating base oil and a compound represented by the following formula (A).

[In Formula (A), R ¹ and R ² each independently represent a monovalent hydrocarbon group, R ³ represents a divalent hydrocarbon group, and X represents a polar group containing a —COOR ⁴ group. R ⁴ represents a hydrogen atom or a monovalent hydrocarbon group. ]

  Examples of the lubricating base oil include hydrocarbon oil and oxygen-containing oil. 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, polysiloxanes, and the like.

  Mineral oil-based hydrocarbon oil is used to remove lubricating oil fractions obtained by atmospheric and vacuum distillation of paraffinic, naphthenic and other crude oils, 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.

The alkyl benzene may be at least one selected from the group consisting of the following alkyl benzene (a1) and alkyl benzene (a2).
Alkylbenzene (a1): an alkylbenzene having 1 to 4 alkyl groups having 1 to 19 carbon atoms and having 9 to 19 carbon atoms in total (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 (a2): 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 (a1) has include 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 and eicosyl group. These alkyl groups may be linear or branched, and are preferably branched from the viewpoint of stability, viscosity characteristics and the like. The alkyl group is a branched alkyl group derived from an oligomer of an olefin such as propylene, butene and isobutylene, particularly from the viewpoint of availability.

  The number of alkyl groups in the alkylbenzene (a1) 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 (a1) may be a single-structure alkylbenzene, has 1 to 4 alkyl groups having 1 to 19 carbon atoms, and satisfies the condition that the total carbon number of the alkyl groups is 9 to 19 If it is alkylbenzene, the mixture of the alkylbenzene which has a different structure may be sufficient.

  Specific examples of the alkyl group having 1 to 40 carbon atoms that the alkylbenzene (a2) 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, Descriptor triacontyl group, octamethylene triacontyl group, and nona triacontyl group and tetracontyl group. These alkyl groups may be linear or branched, and are preferably branched from the viewpoint of stability, viscosity characteristics and the like. The alkyl group is a branched alkyl group derived from an oligomer of an olefin such as propylene, butene and isobutylene, particularly from the viewpoint of availability. From the viewpoint of higher flash point, the alkyl group is more preferably linear or branched derived from a linear alkylating agent such as linear paraffin, linear α-olefin or a halide thereof. An alkyl group, more preferably a branched alkyl group.

  The number of alkyl groups in the alkylbenzene (a2) 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 (a2) may be a single-structure alkylbenzene, has 1 to 4 alkyl groups having 1 to 40 carbon atoms, and satisfies the condition that the total carbon number of the alkyl groups is 20 to 40. If it is alkylbenzene, the mixture of the alkylbenzene which has a different structure may be sufficient.

  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. The ester is preferably a polyol ester or a complex ester.

  The polyol ester is an ester of a polyhydric alcohol and a fatty acid. The fatty acid is preferably a saturated fatty acid. The carbon number 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.

  Among 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%, still more preferably 70 to 100 mol%, and particularly preferably 90. ˜100 mol%.

  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. The fatty acid is preferably a fatty acid having a branch at the α-position and / or β-position, more preferably 2-methylpropanoic acid, 2-methylbutanoic acid, 2-methylpentanoic acid, 2-methylhexanoic acid, 2-ethyl. It is selected from pentanoic acid, 2-methylheptanoic acid, 2-ethylhexanoic acid, 3,5,5-trimethylhexanoic acid and 2-ethylhexadecanoic acid, more preferably 2-methylpropanoic acid and 3,5,5- Selected from trimethylhexanoic acid.

  The fatty acid may contain fatty acids other than fatty acids having 4 to 20 carbon atoms. Fatty acids other than fatty acids having 4 to 20 carbon atoms may be fatty acids having 21 to 24 carbon atoms, for example. The fatty acid having 21 to 24 carbon atoms may be henicoic acid, docosanoic acid, tricosanoic acid, tetracosanoic acid or the like, and may be linear or branched.

  The polyhydric alcohol constituting the polyol ester is preferably a polyhydric alcohol having 2 to 6 hydroxyl groups. The number of carbon atoms of the polyhydric alcohol is preferably 4 to 12, more preferably 5 to 10. The polyhydric alcohol is preferably hindered such as neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), pentaerythritol, dipentaerythritol. More preferred are pentaerythritol, dipentaerythritol, or a mixed ester of pentaerythritol and dipentaerythritol because it is an alcohol and is particularly excellent in compatibility with a 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. Therefore, the complex ester is preferably a complex ester obtained by the method (a) having higher stability.

  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. The polyhydric alcohol having 2 to 4 hydroxyl groups preferably has neopentyl glycol and trimethylol from the viewpoint of securing a suitable viscosity when a complex ester is used as a base oil and obtaining good low temperature characteristics. From the viewpoint of being selected from propane and capable of widely adjusting the viscosity, neopentyl glycol is more preferable.

  From the viewpoint of excellent lubricity, the polyhydric alcohol constituting the complex ester is preferably 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. Is further contained. 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. The dihydric alcohol is preferably butanediol from the viewpoint of excellent lubricating base oil characteristics. Examples of butanediol include 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, and the like. The butanediol is preferably selected from 1,3-butanediol and 1,4-butanediol 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, more preferably 0.8 to 1 mol of the polyhydric alcohol having 2 to 4 hydroxyl groups. It is less than mol, more preferably less than 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. The polybasic acid is preferably selected from adipic acid and sebacic acid, more preferably adipic acid, from the viewpoint of excellent balance of characteristics of the synthesized ester and easy availability. The amount of the polybasic acid having 6 to 12 carbon atoms is preferably 0.4 to 4 mol, more preferably 0.5 to 3 mol per mol of the polyhydric alcohol having 2 to 4 hydroxyl groups. Mol, more preferably 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. The monohydric alcohol is more preferably selected from 2-ethylhexanol and 3,5,5-trimethylhexanol 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 them, 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. The ether is preferably selected from polyvinyl ether and polyalkylene glycol, more preferably polyvinyl ether.

［式（１）中、Ｒ^５０、Ｒ^５１及びＲ^５２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^５３は２価の炭化水素基又は２価のエーテル結合酸素含有炭化水素基を表し、Ｒ^５４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^５３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 ⁵⁰ , R ⁵¹ and R ⁵² may be the same or different from each other, and each represents a hydrogen atom or a hydrocarbon group, and R ⁵³ represents a divalent hydrocarbon group or a divalent ether bond. Represents an oxygen-containing hydrocarbon group, R ⁵⁴ represents a hydrocarbon group, and m represents an integer of 0 or more. When m is 2 or more, the plurality of R ⁵³ may be the same as or different from each other. ]

The number of carbon atoms of the hydrocarbon group represented by R ⁵⁰ , R ⁵¹ and R ⁵² 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 at least one of R ^{50, R 51} and ^{R 52} is a hydrogen ^atom, and more preferably all R ^{50, R 51} and ^{R 52} are hydrogen atoms.

The carbon number of the divalent hydrocarbon group represented by R ⁵³ and the ether bond 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 ⁵³ may be, for example, a hydrocarbon group having oxygen in the side chain to form an ether bond.

R ⁵⁴ 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. The hydrocarbon group is preferably an alkyl group, more preferably an alkyl group having 1 to 5 carbon atoms.

  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 preferably represented by the above formula (1) and R ⁵⁴ is an alkyl group having 1 to 3 carbon atoms and the above structural unit (1-1). And a structural unit (1-2) represented by the formula (1) and R ⁵⁴ is an alkyl group having 3 to 20 carbon atoms. The number of carbon atoms of ^{R 54} in the structural unit (1-2) is preferably 3 to 10, more preferably from 3 to 8. R ⁵⁴ in the structural unit (1-1) is particularly preferably an ethyl group, and R ⁵⁴ in the structural unit (1-2) is particularly preferably an isobutyl group. 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 preferably 5: 95-95: 5, More preferably, it is 20: 80-90: 10, More preferably, it is 70: 30-90: 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.

  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.

［式（２）中、Ｒ^５５〜Ｒ^５８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。］

Wherein ^{(2), R} 55 ~R ⁵⁸ may be the same or different, each represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. ]

  The polyvinyl ether is represented by, for example, polymerization of a vinyl ether monomer corresponding to the structural unit represented by the formula (1), or a vinyl ether monomer corresponding to the structural unit represented by the formula (1) and the formula (2). It is 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^５０、Ｒ^５１、Ｒ^５２、Ｒ^５３、Ｒ^５４及びｍは、それぞれ式（１）中のＲ^５０、Ｒ^５１、Ｒ^５２、Ｒ^５３、Ｒ^５４及びｍと同一の定義内容を示す。］

^{Wherein, R 50, R 51, R} 52, R 53, R 54 and ^{m, R 50, R 51, R} 52, R 53, R 54 and the same definition and m, respectively formula (1) Indicates. ]

  The polyvinyl ether preferably has the following terminal structure (I) or (II).

  (I) 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^５９、Ｒ^６０及びＲ^６１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^６２は炭素数１〜１０の２価の炭化水素基又は２価のエーテル結合酸素含有炭化水素基を示し、Ｒ^６３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^６２は互いに同一でも異なっていてもよい。］

[In the formula (4), R ⁵⁹ , R ⁶⁰ and R ⁶¹ may be the same as or different from each other, and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and R ⁶² has 1 to 10 carbon atoms. Represents a divalent hydrocarbon group or a divalent ether-bonded oxygen-containing hydrocarbon group, R ⁶³ 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 ⁶² may be the same as or different from each other. ]

［式（５）中、Ｒ^６４、Ｒ^６５、Ｒ^６６及びＲ^６７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 ⁶⁴ , R ⁶⁵ , R ⁶⁶ and R ⁶⁷ 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（６）中、Ｒ^６８，Ｒ^６９及びＲ^７０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^７１は炭素数１〜１０の２価の炭化水素基又は２価のエーテル結合酸素含有炭化水素基を示し、Ｒ^７２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^７１は同一でも異なっていてもよい。］

[In the formula (6), R ⁶⁸ , R ⁶⁹ and R ⁷⁰ 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 ⁷¹ has 1 to 10 carbon atoms. A divalent hydrocarbon group or a divalent ether-bonded oxygen-containing hydrocarbon group, R ⁷² 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 ⁷¹ may be the same or different. ]

［式（７）中、Ｒ^７３、Ｒ^７４、Ｒ^７５及びＲ^７６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 the formula (7), R ⁷³ , R ⁷⁴ , R ⁷⁵ and R ⁷⁶ 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. ]

  (II) 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).

［式（８）中、Ｒ^７７、Ｒ^７８及びＲ^７９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。］

[In Formula (8), R ⁷⁷ , R ⁷⁸ and R ⁷⁹ may be the same as or different from each other, and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. ]

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 the formula (4) or (5) and the other end is represented by the formula (6) or (7), and R ⁵⁰ and R in the formula (1) ⁵¹ and R ⁵² are both hydrogen atoms, m is an integer of 0 to 4, R ⁵³ is a divalent hydrocarbon group having 2 to 4 carbon atoms, and R ⁵⁴ 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 ⁵⁰ , R ⁵¹ and R ⁵² are all hydrogen atoms, m is an integer of 0 to 4, R ⁵³ is a divalent hydrocarbon group having 2 to 4 carbon atoms, and R ⁵⁴ is 1 carbon atom. Polyvinyl ether which is ˜20 hydrocarbon groups.
(C) One end is represented by the formula (4) or (5) and the other end is represented by the formula (8), and R ⁵⁰ , R ⁵¹ and R ⁵² in the formula (1) Are all hydrogen atoms, m is an integer of 0 to 4, R ⁵³ is a divalent hydrocarbon group having 2 to 4 carbon atoms, and R ⁵⁴ 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 ⁵⁰ , R ⁵¹ and R ⁵² are all hydrogen atoms, m is an integer of 0 to 4, R ⁵³ is a divalent hydrocarbon group having 2 to 4 carbon atoms, and R ⁵⁴ is 1 carbon atom. Polyvinyl ether which is ˜20 hydrocarbon groups.
(E) any one of the above (a), (b), (c) and (d), wherein R ⁵⁴ in the formula (1) is a hydrocarbon group having 1 to 3 carbon atoms and the R And polyvinyl ether having a structural unit in which ⁵⁴ is a hydrocarbon group having 3 to 20 carbon atoms.

  The weight average molecular weight of polyvinyl ether 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. When the weight average molecular weight of the polyvinyl ether is 500 or more, the refrigerating machine oil is excellent in lubricity in the presence of a refrigerant. When the weight average molecular weight is 3000 or less, the composition range showing compatibility with the refrigerant under a low temperature condition is widened, and poor lubrication of the refrigerant compressor and inhibition of heat exchange in the evaporator can be suppressed.

  The number average molecular weight of the polyvinyl ether 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. When the number average molecular weight of polyvinyl ether is 500 or more, the refrigerating machine oil is excellent in lubricity in the presence of a refrigerant. When the number average molecular weight is 3000 or less, the composition range showing compatibility with the refrigerant under a low temperature condition is widened, and poor lubrication of the refrigerant compressor and inhibition of heat exchange in the evaporator can be suppressed.

  The weight average molecular weight and the number average molecular weight of polyvinyl ether mean the weight average molecular weight and the number average molecular weight (polystyrene (standard sample) conversion value) obtained by GPC analysis, respectively. A weight average molecular weight and a number average molecular weight can be measured as follows, for example.

  Using chloroform as a solvent, a solution is prepared by diluting to a polyvinyl ether concentration of 1% by mass. The solution is analyzed using a GPC apparatus (Waters Alliance 2695). The analysis is performed using a refractive index detector using a column having a solvent flow rate of 1 ml / min and an analyzable molecular weight of 100 to 10,000. The relationship between the column retention time and the molecular weight is determined using a polystyrene standard with a clear molecular weight, a calibration curve is separately prepared, and the molecular weight of the sample is determined from the obtained retention time.

  The degree of unsaturation of the polyvinyl ether is preferably 0.04 meq / g or less, more preferably 0.03 meq / g or less, 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 still more preferably 1.0 meq / kg or less. 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 carbon number of the alkyl group is 10 or less, the refrigerating machine oil tends to be excellent in compatibility with the refrigerant.

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. When the carbon number of the acyl group is 10 or less, the refrigerating machine oil is excellent in compatibility with the refrigerant and tends to hardly cause phase separation.

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, preferably 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. One 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.

  The polyalkylene glycol represented by the formula (9) is preferably a copolymer containing an oxyethylene group (EO) and an oxypropylene group (PO), from the viewpoint of excellent compatibility with a refrigerant and viscosity-temperature characteristics. It is. In this case, from the viewpoint of excellent baking load and viscosity-temperature characteristics, the ratio of oxyethylene groups to the total of oxyethylene groups and oxypropylene groups (EO / (PO + EO)) is preferably 0.1 to 0.8. More preferably, it is 0.3-0.6. 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 even more preferably 0 (ie, propylene oxide homopolymer). It is.

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 weight average molecular weight of the polyalkylene glycol 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. When the weight average molecular weight of the polyalkylene glycol is 500 or more, the refrigerating machine oil is excellent in lubricity in the presence of a refrigerant. When the weight average molecular weight is 3000 or less, the refrigeration oil has a wider composition range that is compatible with the refrigerant under low temperature conditions, and can suppress poor lubrication of the refrigerant compressor and inhibition of heat exchange in the evaporator.

  The number average molecular weight of the polyalkylene glycol 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. When the number average molecular weight of the polyalkylene glycol is 500 or more, the refrigerating machine oil is excellent in lubricity in the presence of a refrigerant. When the number average molecular weight is 3000 or less, the composition range of the refrigerating machine oil that is compatible with the refrigerant under a low temperature condition is widened, and it is possible to suppress poor lubrication of the refrigerant compressor and inhibition of heat exchange in the evaporator.

  The weight average molecular weight and the number average molecular weight of the polyalkylene glycol mean a weight average molecular weight and a number average molecular weight (in terms of polypropylene glycol (standard sample)) obtained by GPC analysis, respectively. A weight average molecular weight and a number average molecular weight can be measured as follows, for example.

  Using chloroform as a solvent, a solution is prepared by diluting to a polyalkylene glycol concentration of 1% by mass. The solution is analyzed using a GPC apparatus (Waters Alliance 2695). The analysis is performed using a refractive index detector using a column having a solvent flow rate of 1 ml / min and an analyzable molecular weight of 100 to 10,000. The relationship between the column retention time and the molecular weight is obtained using a polyalkylene glycol standard with a clear molecular weight, a calibration curve is separately prepared, and the molecular weight of the sample is determined from the obtained retention time.

  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, still more 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 still more preferably 1.0 meq / kg or less. The carbonyl value 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 lubricating base oil is preferably at least one selected from oxygenated oils, more preferably at least one selected from esters and ethers, and even more preferably esters.

The 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, and still more preferably 5 mm ² / s or more. The 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, and still more preferably 400 mm ² / s or less. The kinematic viscosity at 100 ° C. of the lubricating base oil is 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 is 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 refrigerating machine oil contains a compound represented by the following formula (A). Therefore, this refrigerating machine oil is superior in terms of seizure resistance (particularly the effect of improving seizure resistance per unit phosphorus amount) as compared with the case of containing conventional phosphorus additives such as tricresyl phosphate. .

In formula (A), R ¹ and R ² each independently represent a monovalent hydrocarbon group, which may be an alkyl group or an aryl group, and is excellent in seizure resistance in the presence of a refrigerant. An alkyl group is preferred. The alkyl group may be linear or branched. The carbon number of the monovalent hydrocarbon group or alkyl group or aryl group represented by R ¹ and R ² is 2 to 18, 2 to 16, 2 to 14, 2 to 12, 2 to 10, or 2 to 8. It may be.

R ³ represents a divalent hydrocarbon group, and may be, for example, a linear or branched alkylene group. Carbon number of the bivalent hydrocarbon group or alkylene group represented by R ³ may be 1-4, 1-3, 1-2, or 1.

X represents a polar group containing a —COOR ⁴ group. R ⁴ represents a hydrogen atom or a monovalent hydrocarbon group. The monovalent hydrocarbon group represented by R ⁴ may be, for example, a linear or branched alkyl group. Carbon number of the monovalent hydrocarbon group represented by R ⁴ may be 1 to 12, 1 to 8, or 1 to 2.

The polar group containing —COOR ⁴ group represented by X is preferably a polar group containing —COOH group. The polar group including —COOR ⁴ group is represented by, for example, —COOH group, —COOR group, —CH (COOH) CH ₂ COOH group, —CH (COOR) CH ₂ COOH group, and the following formula (X-1). Or a group represented by the following formula (X-2). R in the —COOR group represents a monovalent hydrocarbon group. The hydrocarbon group may be, for example, a linear or branched alkyl group. Carbon number of this hydrocarbon group may be 1-12, 1-8, or 1-2.

  The content of the compound represented by the formula (A) may be 0.01% by mass or more, 0.02% by mass or more, or 0.05% by mass or more based on the total amount of the refrigerating machine oil, and 1.0% by mass. Hereinafter, it may be 0.5% by mass or less or 0.2% by mass or less. The content of the compound represented by the formula (A) is 0.01 to 1.0% by mass, 0.01 to 0.5% by mass, 0.01 to 0.2% by mass, based on the total amount of the refrigerating machine oil. 0.02-1.0 mass%, 0.02-0.5 mass%, 0.02-0.2 mass%, 0.05-1.0 mass%, 0.05-0.5 mass% or It may be 0.05 to 0.2% by mass.

  The refrigerator oil may further contain additives other than the compound represented by the formula (A). Examples of additives other than the compound represented by the formula (A) include acid scavengers, antioxidants, extreme pressure agents, oiliness agents, antifoaming agents, metal deactivators, antiwear agents, and viscosity index improvements. Agents, pour point depressants, detergent dispersants and the like. The content of these additives may be 10% by mass or less or 5% by mass or less based on the total amount of refrigerating machine oil.

  The phosphorus content in the refrigerating machine oil may be 20 mass ppm or more, 50 mass ppm or more, or 80 mass ppm or more, and 1000 mass ppm or less, 500 mass ppm or less, or 200 mass ppm or less, based on the total amount of the refrigerating machine oil. It may be. The content of phosphorus in the refrigerating machine oil is 20 to 1000 mass ppm, 20 to 500 mass ppm, 20 to 200 mass ppm, 50 to 1000 mass ppm, 50 to 500 mass ppm, 50 to 200 mass based on the total amount of the refrigerating machine oil. It may be ppm, 80-1000 mass ppm, 80-500 mass ppm, or 80-200 mass ppm. The “phosphorus content” means a content measured by ICP elemental analysis.

The 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, and further preferably 5 mm ² / s or more. The kinematic viscosity of the refrigerating machine oil at 40 ° C. is preferably 500 mm ² / s or less, more preferably 400 mm ² / s or less, and still more preferably 300 mm ² / s or less.

The kinematic viscosity at 100 ° C. of the refrigerating machine oil is 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 is preferably 100 mm ² / s or less, more preferably 50 mm ² / s or less.

  The pour point of the refrigerating machine oil is 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. . 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 refrigerating machine oil is preferably 200 ppm or less, more preferably 100 ppm or less, still more preferably 50 ppm or less, based on the total amount of the refrigerating machine 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 is 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 this embodiment is usually present in the state of a working fluid composition for a refrigerating machine mixed with a refrigerant in a refrigerating machine. That is, the working fluid composition for a refrigerator according to the present embodiment contains the above-described refrigerator oil and a refrigerant. 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.

  Examples of the refrigerant include saturated fluorinated hydrocarbon refrigerants, unsaturated fluorinated hydrocarbon refrigerants, hydrocarbon refrigerants, fluorinated ether refrigerants such as perfluoroethers, bis (trifluoromethyl) sulfide refrigerant, and trifluoroiodomethane. Examples of the refrigerant include 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. Specific examples of the saturated fluorinated hydrocarbon refrigerant include 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 (R365m c), or a mixture of two or more thereof.

  The saturated fluorinated hydrocarbon refrigerant is appropriately selected from the above depending on the application and required performance. The saturated fluorinated hydrocarbon refrigerant is, for example, R32 alone; R23 alone; R134a alone; R125 alone; a mixture of R134a / R32 = 60 to 80% by mass / 40 to 20% by mass; R32 / R125 = 40 to 70% by mass / 60 -30 mass% mixture; R125 / R143a = 40-60 mass% / 60-40 mass% mixture; R134a / R32 / R125 = 60 mass% / 30 mass% / 10 mass% mixture; R134a / R32 / R125 = 40-70 mass% / 15-35 mass% / 5-40 mass% mixture; R125 / R134a / R143a = 35-55 mass% / 1-15 mass% / 40-60 mass%. More specifically, the saturated fluorinated hydrocarbon refrigerant is 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 wt% mixture (R407C); R32 / R125 / R134a = 25/15/60 wt% mixture (R407E); R125 / R134a / R143a = 44/4/52 wt% (R404A) or the like.

  The unsaturated fluorinated hydrocarbon (HFO) refrigerant is preferably an unsaturated fluorinated hydrocarbon having 2 to 3 carbon atoms, more preferably a fluoropropene, and further preferably a fluoropropene having 3 to 5 fluorine atoms. The unsaturated fluorinated hydrocarbon refrigerant is preferably 1,2,3,3,3-pentafluoropropene (HFO-1225ye), 1,3,3,3-tetrafluoropropene (HFO-1234ze), 2, Any of 3,3,3-tetrafluoropropene (HFO-1234yf), 1,2,3,3-tetrafluoropropene (HFO-1234ye), and 3,3,3-trifluoropropene (HFO-1243zf) One or a mixture of two or more. The unsaturated fluorinated hydrocarbon refrigerant is preferably one or more selected from HFO-1225ye, HFO-1234ze, and HFO-1234yf from the viewpoint of refrigerant physical properties. The unsaturated fluorinated hydrocarbon refrigerant may be fluoroethylene, preferably 1,1,2,3-trifluoroethylene.

  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, the hydrocarbon refrigerant is preferably a hydrocarbon refrigerant which is gaseous at 25 ° C. and 1 atm, and more preferably propane, normal butane, isobutane, 2-methylbutane, or a mixture thereof.

  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 more concretely based on an Example, this invention is not limited to an Example.

  In Examples and Comparative Examples, refrigeration oils having the composition shown in Table 1 (mass% based on the total amount of refrigeration oil) were prepared using the base oils and additives shown below.

ａ１：トリクレジルホスフェート (Base oil)
Base oil: Polyol ester of pentaerythritol and 2-methylpropanoic acid / 3,5,5-trimethylhexanoic acid mixed fatty acid (mass ratio: 35/65) (kinematic viscosity at 40 ° C .: 67. 2 mm ² / s, viscosity index: 84)
(Additive)
A1: Compound represented by the following formula (A-1)

a1: tricresyl phosphate

  About each refrigeration oil of an Example and a comparative example, the seizure resistance was evaluated in the procedure shown below. The results are shown in Table 1.

(Seizure resistance)
The FALEEX Pin / Vee-Block test was performed. Rotating speed: 290 rpm, temperature: 52 ± 8 ° C., oil amount: 120 mL, air condition, running-in for 5 minutes under a load of 300 lbf, and then applying the load, seizure occurred The load at the time was defined as a seizure load. In addition, the ASTM standard piece was used as a test piece.

Claims (2)

A refrigerating machine oil containing a lubricating base oil and a compound represented by the following formula (A).

[In Formula (A), R ¹ and R ² each independently represent a monovalent hydrocarbon group, R ³ represents a divalent hydrocarbon group, and X represents a polar group containing a —COOR ⁴ group. R ⁴ represents a hydrogen atom or a monovalent hydrocarbon group. ]   The working fluid composition for refrigerators containing the refrigerator oil of Claim 1, and a refrigerant | coolant.