JPWO2018021533A1 - Refrigeration oil - Google Patents

Abstract

The present invention provides a refrigerator oil containing a lubricant base oil and a compound represented by the following formula (A). [Wherein, Ra and Rb each independently represent a monovalent hydrocarbon group, Rc represents a divalent hydrocarbon group, X represents a polar group, and Za and Zb are each independently oxygen Represents an atom or a sulfur atom. ]

Description

  The present invention relates to refrigeration oil.

  Refrigerators such as refrigerators, car air conditioners, room air conditioners, and vending machines are provided with a compressor for circulating a refrigerant into the refrigeration cycle. The compressor is then filled with refrigeration oil for lubricating the sliding member. Refrigerant oil is required to have properties such as wear resistance and stability.

  Refrigerant oils generally contain lubricating base oils and additives which are selected according to the above-mentioned required properties. Conventionally, as an additive (antiwear agent) for improving abrasion resistance, orthophosphoric acid ester, acidic phosphoric acid ester, etc. are used (for example, patent documents 1, 2).

Japanese Patent Application Laid-Open No. 11-256182 Japanese Patent Laid-Open No. 2000-282076

  However, refrigerator oils containing orthophosphate or acid phosphate as an antiwear agent still have room for improvement in terms of abrasion resistance. In addition, although an acid phosphoric acid ester exhibits high abrasion resistance compared with a regular phosphoric acid ester, a problem may arise in the point of stability.

  Under such circumstances, the present inventors focused on the improvement of the wear resistance and developed a refrigerator oil. That is, an object of the present invention is to provide a refrigerator oil having excellent abrasion resistance.

［式中、Ｒ^ａ及びＲ^ｂはそれぞれ独立に１価の炭化水素基を表し、Ｒ^ｃは２価の炭化水素基を表し、Ｘは極性基を表し、Ｚ^ａ及びＺ^ｂはそれぞれ独立に酸素原子又は硫黄原子を表す。］The present invention provides a refrigerator oil containing a lubricant base oil and a compound represented by the following formula (A).

[Wherein, R ^a and R ^b each independently represent a monovalent hydrocarbon group, R ^c represents a divalent hydrocarbon group, X represents a polar group, and Z ^a and Z ^b are each independently. Represents an oxygen atom or a sulfur atom. ]

  The refrigerator oil preferably contains, as a lubricant base oil, at least one oxygenated oil selected from the group consisting of esters and ethers.

  The refrigerator oil preferably further contains an epoxy compound.

  The refrigeration oil is preferably selected from the group consisting of 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 as epoxy compounds. It contains at least one selected.

  The refrigeration oil preferably contains, as an epoxy compound, at least one selected from the group consisting of glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, and alicyclic epoxy compounds.

  The polar group represented by X in formula (A) preferably has an oxygen atom.

  ADVANTAGE OF THE INVENTION According to this invention, refrigeration oil which is excellent in abrasion resistance can be provided.

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

［式中、Ｒ^ａ及びＲ^ｂはそれぞれ独立に１価の炭化水素基を表し、Ｒ^ｃは２価の炭化水素基を表し、Ｘは極性基を表し、Ｚ^ａ及びＺ^ｂはそれぞれ独立に酸素原子又は硫黄原子を表す。］The refrigeration oil according to one embodiment contains a lubricant base oil and a compound represented by the following formula (A).

[Wherein, R ^a and R ^b each independently represent a monovalent hydrocarbon group, R ^c represents a divalent hydrocarbon group, X represents a polar group, and Z ^a and Z ^b are each independently. Represents an oxygen atom or a sulfur atom. ]

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

  Mineral oil-based hydrocarbon oils are solvent-depleted, solvent-refined, hydrorefined, hydrocracked, solvent-degraded, and lubricating oil fractions obtained by atmospheric distillation and vacuum distillation of crude oils such as paraffinic and naphthenic crude oils. It can be obtained by purification by methods such as wax, hydrodewaxing, clay treatment, sulfuric acid washing and the like. These purification methods may be used alone or in combination of two or more.

  Examples of synthetic hydrocarbon oils include alkylbenzenes, alkylnaphthalenes, poly α-olefins (PAO), polybutenes, ethylene-α-olefin copolymers, and the like.

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

  Specific examples of the alkyl group having 1 to 19 carbon atoms possessed by the alkylbenzene (A) include, for example, methyl group, ethyl group, propyl group (including all isomers, hereinafter the same), butyl group, pentyl group, hexyl Groups, heptyl groups, octyl groups, nonyl groups, decyl groups, undecyl groups, dodecyl groups, tridecyl groups, tetradecyl groups, pentadecyl groups, hexadecyl groups, heptadecyl groups, octadecyl groups, nonadecyl groups and eicosyl groups. These alkyl groups may be linear or branched, and are preferably branched in terms of stability, viscosity characteristics and the like. The alkyl group is preferably 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 (A) is 1 to 4 and, in terms of stability and availability, preferably 1 or 2 (ie, monoalkylbenzene, dialkylbenzene or a mixture thereof) is there.

  The alkylbenzene (A) may contain only alkylbenzene having a single structure, has 1 to 4 alkyl groups having 1 to 19 carbon atoms, and the total carbon number of the alkyl groups is 9 to 19 If the alkylbenzene satisfies the conditions, it may contain a mixture of alkylbenzenes having different structures.

  Specific examples of the alkyl group having 1 to 40 carbon atoms possessed by the alkylbenzene (B) include, for example, methyl group, ethyl group, propyl group (including all isomers, hereinafter the same), butyl group, pentyl group, hexyl 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, henicosyl group, docosyl group, Tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacocyl group, triacontyl group, hetriaconyl group, dotriacontyl group, tritriacontyl group, tetratriacontyl group, pentatriacontyl group, hexa Triacontyl group, He Tatoriakonchiru group, octamethylene triacontyl group, nona triacontyl group, and a tetracontyl group. These alkyl groups may be linear or branched, and are preferably branched in terms of stability, viscosity characteristics and the like. The alkyl group is preferably a branched alkyl group derived from an oligomer of an olefin such as propylene, butene and isobutylene, particularly from the viewpoint of availability. The alkyl group is more preferably a linear or branched alkyl derived from a linear alkylating agent such as a linear paraffin, a linear α-olefin or a halide thereof from the viewpoint of higher flash point. It is a group, more preferably a branched alkyl group.

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

  The alkylbenzene (B) may contain only alkylbenzene having a single structure, and 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 the alkylbenzene satisfies the conditions, it may contain a mixture of alkylbenzenes having different structures.

  Poly (alpha) -olefin (PAO) is a compound obtained, for example, by polymerizing several molecules of a linear olefin of 6 to 18 carbon atoms having a double bond only at one of the ends, and then hydrogenation. The poly α-olefin may be, for example, iso-paraffin having a molecular weight distribution centered on α-decene having 10 carbon atoms or a trimer or tetramer of α-dodecene having 12 carbon atoms.

  Examples of the ester include aromatic esters, dibasic acid esters, polyol esters, complex esters, carbonic esters and mixtures thereof. The ester is preferably a polyol ester or complex ester.

  The polyol ester is an ester of a polyhydric alcohol and a fatty acid. As fatty acid, saturated fatty acid is preferably used. 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 a part of hydroxyl groups of polyhydric alcohol is not esterified and remains as a hydroxyl group, or may be a complete ester in which all the hydroxyl groups are esterified, or a partial ester It may be a mixture of an ester and a complete ester. The hydroxyl value of the polyol ester is preferably 10 mg KOH / g or less, more preferably 5 mg KOH / g or less, and still more preferably 3 mg KOH / g or less.

  Among fatty acids constituting the polyol ester, the proportion of the fatty acid 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%, particularly preferably 90 And 100 mol%.

  Specifically as a C4-C20 fatty acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid And hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid and icosanic 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 the 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, and more preferably 2-ethylhexanoic acid and 3,5,5- It is selected from trimethylhexanoic acid.

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

  As a polyhydric alcohol which comprises polyol ester, the polyhydric alcohol which has a 2-6 hydroxyl group is used preferably. The carbon number of the polyhydric alcohol is preferably 4 to 12, more preferably 5 to 10. Polyhydric alcohols are preferably hindered such as neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), pentaerythritol, dipentaerythritol and the like. It is an alcohol, and is particularly preferably pentaerythritol, dipentaerythritol, or a mixed alcohol of pentaerythritol and dipentaerythritol, since it is particularly excellent in compatibility with a refrigerant and hydrolysis stability.

The complex ester is, for example, an ester synthesized by the following method (a) or (b).
(A) Adjusting the molar ratio of polyhydric alcohol to polybasic acid to synthesize an ester intermediate in which a part of the carboxyl group of the polybasic acid remains without being esterified, and then the remaining carboxyl group is Method of esterifying with a monohydric alcohol (b) Adjusting the molar ratio of polyhydric alcohol and polybasic acid to synthesize an ester intermediate in which a part of hydroxyl groups of polyhydric alcohol remains without being esterified, Then, the remaining hydroxyl group is esterified with a monovalent fatty acid

  The complex ester obtained by the above method (b) is relatively poor in stability compared to the complex ester obtained by the above method (a) because a relatively strong acid is formed when it is hydrolyzed when used as a refrigerator oil There is a tendency. Therefore, the complex ester is preferably a complex ester obtained by the method of the above (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 having 4 to 18 carbon atoms. It is an ester synthesized from at least one selected from monohydric alcohol and C 2-12 monohydric fatty acid.

  Examples of polyhydric alcohols having 2 to 4 hydroxyl groups include neopentyl glycol, trimethylolpropane and pentaerythritol. A polyhydric alcohol having 2 to 4 hydroxyl groups is preferably neopentyl glycol and trimethylol from the viewpoint of securing a suitable viscosity when using a complex ester as a base oil and obtaining good low temperature properties. From the viewpoint of being selected from propane and capable of widely controlling viscosity, neopentyl glycol is more preferable.

  From the viewpoint of excellent lubricity, the polyhydric alcohol constituting the complex ester is preferably a polyhydric alcohol having 2 to 4 hydroxyl groups, and a dihydric alcohol having 2 to 10 carbon atoms other than neopentyl glycol. Further contains As dihydric alcohols having 2 to 10 carbon atoms other than neopentyl glycol, ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5 -Pentanediol, 2,2-diethyl-1,3-pentanediol and the like. The dihydric alcohol is preferably butanediol from the viewpoint of the excellent properties of the lubricating base oil. As butanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol and the like can be mentioned. Butanediol is preferably selected from 1,3-butanediol and 1,4-butanediol from the viewpoint of obtaining good properties. 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, per mol of polyhydric alcohol having 2 to 4 hydroxyl groups. It is preferably at most mol, more preferably at most 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 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, more preferably 0.5 mol to 3 mol per mol of polyhydric alcohol having 2 to 4 hydroxyl groups. The mole is more preferably 0.6 to 2.5 moles.

  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 C4-18 monohydric alcohol is preferably a C6-10 monohydric alcohol, more preferably a C8-10 monohydric alcohol, from the viewpoint of the balance of properties. The monohydric alcohol is more preferably selected from 2-ethylhexanol and 3,5,5-trimethylhexanol from the viewpoint of improving the low temperature properties of the synthesized complex ester.

  Examples of the monohydric 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 C 2 to C 12 monohydric fatty acid is preferably a C 8 to C 10 monohydric fatty acid, and among them, from the viewpoint of low-temperature properties, more preferably 2-ethylhexanoic acid, 3,5,5-trimethyl It is hexanoic acid.

  Examples of the ether include polyvinyl ether, polyalkylene glycol, polyphenyl ether, perfluoroether and mixtures thereof. The ether is preferably selected from polyvinyl ethers and polyalkylene glycols, more preferably polyvinyl ethers.

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

The carbon number 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 More preferably, it is 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 and the ether-linked oxygen-containing hydrocarbon group represented by R ⁴ 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-bonded oxygen-containing hydrocarbon group represented by R ⁴ may be, for example, a hydrocarbon group having an oxygen at the side chain which forms 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. 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, further preferably 2 or more, and preferably 20 or less, more preferably 18 or less, further preferably 16 or less. The average value of m in all structural units constituting the polyvinyl ether is preferably 0 to 10.

  The polyvinyl ether may be a homopolymer composed of one selected from structural units represented by formula (1), and may be composed of two or more selected from structural units represented by formula (1) The copolymer may be a copolymer of the structural unit represented by the formula (1) and another structural unit. When the polyvinyl ether is a copolymer, lubricity, insulation, hygroscopicity, and the like can be further improved while satisfying the compatibility of the refrigerator oil with the refrigerant. Under the present circumstances, it becomes possible to make various characteristics of said refrigerator oil into a desired thing by selecting suitably the kind of monomer used as a raw material, the kind of initiator, the ratio of the structural unit in a copolymer, etc. The copolymer may be either a block copolymer or a random copolymer.

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

[In Formula (2), R ^{6 to} R ⁹ 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。］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 a vinyl ether type monomer corresponding to the structural unit represented by Formula (1), the monomer represented by following formula (3) is suitable.

^{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 formula (4), R ¹¹ , R ²¹ and R ³¹ may be the same as or different from each other, each representing a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and R ⁴¹ has 1 to 10 carbon atoms R 2 represents 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 has 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（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 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^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^４２は同一でも異なっていてもよい。］

[In formula (6), R ¹² , R ²² and R ³² may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and R ⁴² is 1 to 10 carbon atoms R represents 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 is the same as m in formula (1) Show. When m is 2 or more, a plurality of R ⁴² 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 be the same as or different from each other, and each independently represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. ]

Among such polyvinyl ethers, polyvinyl ethers (a), (b), (c), (d) and (e) listed below are particularly preferable as the base oil.
(A) R ¹ and R in Formula (1) have a structure in which one end is represented by Formula (4) or (5) and the other end is represented by Formula (6) or (7) Polyvinyl ether in which each of ² and R ³ is a hydrogen atom, 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) having only the structural unit represented by the formula (1), wherein one end is represented by the formula (4) and the other end is represented by the formula (6) R ¹ , R ² and R ³ in the formula (1) are each a hydrogen atom, 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 1 carbon atom Polyvinyl ether which is a -20 hydrocarbon group.
(C) R ¹ , R ² and R ³ in the formula (1) have one end represented by the formula (4) or (5) and the other end represented by the formula (8) Each is a hydrogen atom, 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) having only the structural unit represented by the formula (1), having one end represented by the formula (5) and the other end represented by the formula (8) R ¹ , R ² and R ³ in the formula (1) are each a hydrogen atom, 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 1 carbon atom Polyvinyl ether which is a -20 hydrocarbon group.
(E) A structural unit which is any one of the above (a), (b), (c) and (d) and in which R ⁵ in the formula (1) is a hydrocarbon group having 1 to 3 carbon atoms Polyvinyl ether which has a structural unit whose ⁵ is a C3-C20 hydrocarbon group.

  The weight average molecular weight of the polyvinyl ether is preferably 500 or more, more preferably 600 or more, and preferably 3000 or less, more preferably 2000 or less, still more preferably 1500 or less. When the weight average molecular weight of the polyvinyl ether is 500 or more, the lubricity in the coexistence of the refrigerant is excellent. When the weight average molecular weight is 3000 or less, the composition range showing compatibility with the refrigerant under low temperature conditions is broadened, and the lubricating failure of the refrigerant compressor and the 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, and preferably 3000 or less, more preferably 2000 or less, still more preferably 1500 or less. When the number average molecular weight of the polyvinyl ether is 500 or more, the lubricity in the coexistence of the refrigerant is excellent. When the number average molecular weight is 3,000 or less, the composition range showing compatibility with the refrigerant under low temperature conditions is broadened, and the lubrication failure of the refrigerant compressor and the inhibition of heat exchange in the evaporator can be suppressed.

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

  Chloroform is used as a solvent and diluted to prepare a solution having a polyvinyl ether concentration of 1% by mass. The solution is analyzed using a GPC apparatus (Waters Alliance 2695). The solvent flow rate is 1 ml / min, an analytical molecular weight of 100 to 10000 is used, and analysis is performed using a refractive index detector. The relationship between the column retention time and the molecular weight is determined using a polystyrene standard having a clear molecular weight, and a calibration curve is separately prepared, and then 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 the polyvinyl ether is preferably 10.0 meq / kg or less, more preferably 5.0 meq / kg or less, still more preferably 1.0 meq / kg or less. The carbonyl number of the polyvinyl ether is preferably 100 ppm by weight or less, more preferably 50 ppm by weight or less, and further preferably 20 ppm by weight or less. The hydroxyl value of the polyvinyl ether is preferably 10 mg KOH / g or less, more preferably 5 mg KOH / g or less, and still more preferably 3 mg KOH / g or less.

  The degree of unsaturation, the peroxide number and the carbonyl number in the present invention refer to values measured by the standard fat and oil analysis test method established by the Japan Oil Chemistry Association. That is, in the present invention, the degree of unsaturation is determined by reacting a sample with Wis solution (ICl-acetic acid solution), leaving it in the dark, and then reducing excess ICl to iodine and titrating iodine with sodium thiosulfate. The iodine value is calculated, and the value (meq / g) is obtained by converting the iodine value to a vinyl equivalent. In the peroxide value in the present invention, potassium iodide is added to the sample, and the resulting free iodine is titrated with sodium thiosulfate, and this free iodine is converted into the number of milliequivalents per 1 kg of sample (meq / kg). Say. In the present invention, the carbonyl value is obtained by reacting 2,4-dinitrophenylhydrazine on a sample to generate a chromogenic quinoid ion, measuring the absorbance at 480 nm of this sample, and determining a calibration curve using cinnamaldehyde as a standard substance in advance. The value (weight ppm) converted to the amount of carbonyl on the basis of The hydroxyl value in the present invention means a hydroxyl value measured in accordance with JIS K 0070: 1992.

  Examples of polyalkylene glycols include polyethylene glycol, polypropylene glycol, polybutylene glycol and the like. The 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 ethylene oxide, propylene oxide and butylene oxide as monomers as raw materials, respectively.

As a polyalkylene glycol, the compound represented, for example by following formula (9) is mentioned.
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 is carbon And 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; Represents an integer of 8. ]

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

The alkyl group portion of the acyl group represented by R ^α or R ^γ may be linear, branched or cyclic. The carbon number of the acyl group is preferably 2 to 10, more preferably 2 to 6. When the carbon number of the acyl group exceeds 10, the compatibility with the refrigerant may be reduced to cause phase separation.

When the groups represented by R ^α and R ^γ are both alkyl groups or both are acyl groups, the groups represented by R ^α and R ^γ may be the same or different. When g is 2 or more, the 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 ^α is a residue of a compound having 2 to 8 hydroxyl groups, this compound may be linear or cyclic.

From the viewpoint of excellent compatibility, 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 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 easiness of production and cost, it is preferable that 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, it is preferable that both R ^α and R ^γ be a hydrogen atom.

R ^β represents an alkylene group having 2 to 4 carbon atoms, and specific examples of such an alkylene group include an ethylene group, a propylene group and a butylene group. Moreover, as an oxyalkylene group of the repeating unit represented by OR ( ^beta) , oxyethylene group, oxypropylene group, oxybutylene group is mentioned. The oxyalkylene group represented by (OR ^β ) _f may be composed 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 comprising an oxyethylene group (EO) and an oxypropylene group (PO) from the viewpoint of excellent compatibility with the refrigerant and viscosity-temperature characteristics. It is union. In this case, the ratio of the oxyethylene group to the total of the oxyethylene group and the oxypropylene group (EO / (PO + EO)) is preferably 0.1 to 0.8, from the viewpoint of excellent baking load and viscosity-temperature characteristics. And more preferably 0.3 to 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, still more preferably 0 (that is, propylene oxide homopolymer) It is.

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

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

  The weight average molecular weight of the polyalkylene glycol is preferably 500 or more, more preferably 600 or more, and preferably 3000 or less, more preferably 2000 or less, still more preferably 1500 or less. When the weight average molecular weight of the polyalkylene glycol is 500 or more, the lubricity in the presence of a refrigerant is excellent. When the weight average molecular weight is 3000 or less, the composition range showing compatibility with the refrigerant under low temperature conditions is broadened, and the lubricating failure of the refrigerant compressor and the inhibition of heat exchange in the evaporator can be suppressed.

  The number average molecular weight of the polyalkylene glycol is preferably 500 or more, more preferably 600 or more, and preferably 3000 or less, more preferably 2000 or less, still more preferably 1500 or less. When the number average molecular weight of the polyalkylene glycol is 500 or more, the lubricity in the coexistence of the refrigerant is excellent. When the number average molecular weight is 3,000 or less, the composition range showing compatibility with the refrigerant under low temperature conditions is broadened, and the lubrication failure of the refrigerant compressor and the inhibition of heat exchange in the evaporator can be suppressed.

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

  Chloroform is used as a solvent and diluted to prepare a solution having a polyalkylene glycol concentration of 1% by mass. The solution is analyzed using a GPC apparatus (Waters Alliance 2695). The solvent flow rate is 1 ml / min, an analytical molecular weight of 100 to 10000 is used, and analysis is performed using a refractive index detector. The relationship between the column retention time and the molecular weight is determined using a polyalkylene glycol standard having a clear molecular weight, and a calibration curve is separately prepared, and then the molecular weight of the sample is determined from the obtained retention time.

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

The polyalkylene glycol can be synthesized using a known method ("Alkylene oxide polymer", Mitsuta Shibata et al., Kaibundo, published 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 the formula (9) is obtained. When two or more alkylene oxides are used in the above-mentioned production process, the polyalkylene glycol obtained may be either a random copolymer or a block copolymer, but tends to be excellent in oxidation stability and lubricity. From the point of point to point, it is preferably a block copolymer, and from the point of being more excellent in low temperature fluidity, it is preferably a random copolymer.

  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, 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 further preferably 20 ppm by weight or less.

  The lubricant base oil is preferably at least one selected from oxygenated oils, and more preferably at least one selected from esters and ethers.

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 preferably be 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 preferably be 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 in accordance with JIS K 2283: 2000.

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

式（Ａ−１）〜（Ａ−３）中、Ｒ^ａ、Ｒ^ｂ、Ｒ^ｃ及びＸは、式（Ａ）中のＲ^ａ、Ｒ^ｂ、Ｒ^ｃ及びＸとそれぞれ同義である。The compound represented by the formula (A) is preferably a compound represented by any one of the following formulas (A-1) to (A-3).

Wherein (A-1) ~ (A -3), R a, R b, R c and X are ^{R a,} R b in the formula (A), respectively ^{R c} and X synonymous.

The carbon number of the monovalent hydrocarbon group represented by R ^a and R ^b may be 2 to 18, 2 to 16, 2 to 14, 2 to 12, 2 to 10 or 2 to 8. The monovalent hydrocarbon group may be a linear or branched alkyl group. The carbon number of the divalent hydrocarbon group represented by R ^c may be 1 to 4, 1 to 3, 1 to 2, or 1. The divalent hydrocarbon group may be a linear or branched alkylene group.

Ｘで表される極性基は、好ましくは、−ＯＨ基、−ＣＯＯＨ基、−ＣＯＯＲ基、−ＣＨ（ＣＯＯＨ）ＣＨ_２ＣＯＯＨ基、又は−ＣＨ（ＣＯＯＲ）ＣＨ_２ＣＯＯＨ基である。上記−ＣＯＯＲ基、−ＮＲ_２基、−ＣＨ（ＣＯＯＲ）ＣＨ_２ＣＯＯＨ基中のＲは、１価の炭化水素基であってよく、直鎖又は分岐のアルキル基であってよい。該１価の炭化水素基及びアルキル基の炭素数は、１〜１２、１〜８又は１〜２であってよい。The polar group represented by X may have an oxygen atom. The polar group is, for example, -OH group, -COOH group, -COOR group, -CONHNH ₂ group, -CONH ₂ group, -NR ₂ group, -CN group, -CH (COOH) CH ₂ COOH group, -CH (COOR) CH ₂ COOH group or any of the groups represented by the following formulas (x-1) to (x-4).

The polar group represented by X is preferably an —OH group, a —COOH group, a —COOR group, a —CH (COOH) CH ₂ COOH group, or a —CH (COOR) CH ₂ COOH group. R in the -COOR group, -NR ₂ group, -CH (COOR) CH ₂ COOH group may be a monovalent hydrocarbon group, and may be a linear or branched alkyl group. The carbon number of the monovalent hydrocarbon group and the alkyl group may be 1 to 12, 1 to 8, or 1 to 2.

式中、Ｒ^ｄ及びＲ^ｅはそれぞれ独立に炭素数２〜８の直鎖又は分岐のアルキル基を表し、Ｘ^ａは−ＯＨ基、−ＣＯＯＨ基又は−ＣＯＯＲ’基（Ｒ’は炭素数１〜８の直鎖又は分岐のアルキル基を表す）を表す。The compound represented by Formula (A) may be a compound represented by a following formula (A-4) as one preferable aspect.

In the formula, R ^d and R ^e each independently represent a linear or branched alkyl group having 2 to 8 carbon atoms, X ^a is —OH group, —COOH group or —COOR ′ group (R ′ is 1 carbon atom Represents a linear or branched alkyl group of 8 to 8).

  The content of the compound represented by the formula (A) may be 0.005% by mass or more, 0.01% by mass or more, or 0.02% by mass or more, based on the total mass of the refrigerator oil, 0.1% by mass Hereinafter, it may be 0.2% by mass or less or 1% by mass or less. The content of the compound represented by the formula (A) is 0.005 to 0.1% by mass, 0.005 to 0.2% by mass, 0.005 to 1% by mass, 0. 01 to 0.1 mass%, 0.01 to 0.2 mass%, 0.01 to 1 mass%, 0.02 to 0.1 mass%, 0.02 to 0.2 mass% or 0.02 to It may be 1% by mass.

  The refrigerator oil may further contain an epoxy compound. As an epoxy compound, a glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, an oxirane compound, an alkyl oxirane compound, an alicyclic epoxy compound, an epoxidized fatty acid monoester, an epoxidized vegetable oil etc. are mentioned. These epoxy compounds may be used alone or in combination of two or more.

式中、Ｒ^ｆは炭素数６〜１８のアリール基又は炭素数５〜１８のアルキル基を表す。The glycidyl ether type epoxy compound may be, for example, an aryl glycidyl ether type epoxy compound or an alkyl glycidyl ether type epoxy compound represented by the following formula (B-1).

In formula, R ^f represents a C6-C18 aryl group or a C5-C18 alkyl group.

  The glycidyl ether type epoxy compound represented by the formula (B-1) is preferably 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 Or 2-ethylhexyl glycidyl ether.

  The glycidyl ether type epoxy compound may be a compound other than the epoxy compound represented by the formula (B-1). Specifically, neopentyl glycol diglycidyl ether, trimetylolpropane triglycidyl ether, pentaerythritol tetramer It may be glycidyl ether, 1,6-hexanediol diglycidyl ether, sorbitol polyglycidyl ether, polyalkylene glycol monoglycidyl ether, polyalkylene glycol diglycidyl ether and the like.

式中、Ｒ^ｇは炭素数６〜１８のアリール基、炭素数５〜１８のアルキル基、又は炭素数５〜１８のアルケニル基を表す。The glycidyl ester type epoxy compound may be, for example, a compound represented by the following formula (B-2).

In formula, R < ^g > represents a C6-C18 aryl group, a C5-C18 alkyl group, or a C5-C18 alkenyl group.

  The glycidyl ester type epoxy compound represented by Formula (B-2) is preferably glycidyl benzoate, glycidyl neodecanoate, glycidyl-2,2-dimethyloctanoate, glycidyl acrylate, or glycidyl methacrylate.

The alicyclic epoxy compound is a compound represented by the following formula (B-3) and having a partial structure in which a carbon atom constituting the epoxy group directly constitutes an alicyclic ring.

  Alicyclic epoxy compounds are, for example, 1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 3 ', 4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis (3,4-epoxy) Cyclohexylmethyl) adipate, exo-2,3-epoxy norbornane, 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, It may be 4-epoxyethyl-1,2-epoxycyclohexane.

  Examples of the allyl oxirane compound include 1,2-epoxystyrene, alkyl-1,2-epoxystyrene and the like.

  As the alkyl oxirane compound, 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 thereof include 2-epoxyheptadecane, 1,2-epoxyoctadecane, 1,2-epoxy nonadecane, and 1,2-epoxyicosane.

  Examples of the epoxidized fatty acid monoester include esters of an epoxidized fatty acid having 12 to 20 carbon atoms and an alcohol having 1 to 8 carbon atoms or phenol or an alkylphenol. The epoxidized fatty acid monoester is preferably a butyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl, phenyl or butylphenyl ester of epoxystearic acid.

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

  When the refrigerator oil contains both the compound represented by the formula (A) and the epoxy compound, the refrigerator oil is only resistant to abrasion, for example, as compared to a conventional refrigerator oil containing an acidic phosphoric acid ester and an epoxy compound. It is also excellent in stability. The epoxy compound is preferably at least one selected from glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, and alicyclic epoxy compounds from the viewpoint of achieving both wear resistance and stability, and more preferably, It is at least one selected from glycidyl ether type epoxy compounds and glycidyl ester type epoxy compounds.

  The content of the epoxy compound is preferably 0.1% by mass or more, more preferably 0.15% by mass or more, still more preferably 0.2% by mass or more, based on the total amount of the refrigerator oil, from the viewpoint of improving the stability. is there. The content of the epoxy compound is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, still more preferably 2.0% by mass or less, based on the total amount of refrigeration oil, from the viewpoint of improving lubricity. is there.

  The refrigerator oil may further contain other additives. Other additives include, for example, acid scavengers other than epoxy compounds, antioxidants, extreme pressure agents, oil agents, antifoaming agents, metal deactivators, resistance to compounds other than compounds represented by formula (A) Abrasive agents, viscosity index improvers, pour point depressants, detergent dispersants, etc. may be mentioned. The content of these additives may be 10% by mass or less or 5% by mass or less based on the total amount of the refrigerator oil.

  The refrigerator oil preferably further contains, among the above-mentioned other additives, at least one of an antioxidant and an antiwear agent other than the compound represented by the formula (A). The antioxidant is 2,6-di-tert. It may be a phenol-based antioxidant such as -butyl-p-cresol or bisphenol A, or an amine-based antioxidant such as alkylphenyl α-naphthylamine or dialkyl diphenylamine. Antiwear agents other than compounds represented by the formula (A) include phosphates, acid phosphates, thiophosphates, amine salts of acid phosphates, phosphorus such as chlorinated phosphates and phosphites, etc. It may be a system antiwear agent.

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 refrigerator 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 refrigerator oil may preferably be 100 mm ² / s or less, more preferably 50 mm ² / s or less.

  The pour point of the refrigerator oil may be preferably −10 ° C. or less, more preferably −20 ° C. or less. The pour point in the present invention means a pour point measured in accordance with JIS K 2269-1987.

The volume resistivity of the refrigeration oil is preferably 1.0 × 10 ⁹ Ω · m or more, more preferably 1.0 × 10 ¹⁰ Ω · m or more, and still more preferably 1.0 × 10 ¹¹ Ω · m or more. You may The volume resistivity in the present invention means the volume resistivity at 25 ° C. measured in accordance with JIS C2101: 1999.

  The water content of the refrigerator oil may be 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 refrigerator oil.

  The acid value of the refrigerator oil may be preferably 1.0 mg KOH / g or less, more preferably 0.1 mg KOH / g or less. The acid value in the present invention means an acid value measured in accordance with JIS K 2501: 2003.

  The ash content of the refrigerator oil may preferably be 100 ppm or less, more preferably 50 ppm or less. The ash content in the present invention means ash content measured in accordance with JIS K2272: 1998.

  The refrigeration oil according to the present embodiment is used together with a refrigerant. As the refrigerant, a saturated fluorinated hydrocarbon refrigerant, an unsaturated fluorinated hydrocarbon refrigerant, a hydrocarbon refrigerant, a fluorine-containing ether refrigerant such as perfluoroethers, a bis (trifluoromethyl) sulfide refrigerant, methane trifluoride iodide Examples of the refrigerant include natural refrigerants such as ammonia and carbon dioxide, and mixed refrigerants containing one or more of these refrigerants.

  The saturated fluorinated hydrocarbon refrigerant preferably includes saturated fluorinated hydrocarbons having preferably 1 to 3 carbon atoms, and 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 (R134a) 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 thereof Thing, and the like.

  The saturated fluorinated hydrocarbon refrigerant is appropriately selected from the above depending on the application and required performance, but, for example, R32 alone; R23 alone; R134a alone; R125 alone; R134a / R32 = 60 to 80% by mass / 40 R32 / R125 = 40-70% by mass / 60-30% by mass mixture; R125 / R143a = 40-60% by mass / 60-40% by mass mixture; R134a / R32 / R125 = 60 A 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% A mixture of 1 to 15% by mass and 40 to 60% by mass is a preferable example. 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 Mixture of 55% by mass (R410B); mixture of R125 / R143a = 50/50% by mass (R507C); mixture of R32 / R125 / R134a = 30/10/60% by mass; R32 / R125 / R134a = 23/25 A mixture of 52% by mass (R407C); a mixture of R32 / R125 / R134a = 25/15/60% by mass (R407E); a mixture of R125 / R134a / R143a = 44/4/52% by mass (R404A) and the like be able to.

  The unsaturated fluorinated hydrocarbon (HFO) refrigerant is preferably an unsaturated fluorinated hydrocarbon having 2 to 3 carbon atoms, more preferably fluoropropene, still more preferably 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), 2,2,3 Any of 3,3,3-tetrafluoropropene (HFO-1234yf), 1,2,3,3-tetrafluoropropene (HFO-1234ye), and 3,3,3-trifluoropropene (HFO-1243zf) It is a mixture of one or more kinds. 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 (HFO-1123). The unsaturated fluorinated hydrocarbon refrigerant may be 1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd), cis-1-chloro-2,3,3,3-tetra It may be any of fluoropropene (HCFO-1224yd (Z)), trans-1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd (E)) and a mixture thereof.

  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, methyl cyclopropane, 2-methyl butane, normal pentane, or two or more of these. A mixture of Among these, a hydrocarbon refrigerant gaseous at 25 ° C. and 1 atm. Pressure is preferably used, and propane, normal butane, isobutane, 2-methyl butane or a mixture thereof is more preferably used.

  The refrigerant used together with the refrigerating machine oil according to the present embodiment may be a mixed refrigerant containing one or more selected from the above-mentioned refrigerants, for example, one or more selected from unsaturated hydrocarbon (HFO) refrigerants A mixed refrigerant of two or more refrigerants and one or more refrigerants selected from saturated fluorinated hydrocarbon (HFC) refrigerants, or one or a mixture selected from a hydrocarbon refrigerant and a natural refrigerant. It may be a mixed refrigerant obtained by further mixing two or more refrigerants. More specifically, the refrigerant is, for example, one or more HFO refrigerants selected from HFO-1225ye, HFO-1234ze, HFO-1234yf, HFO-1123, HCFO-1224yd, etc., R32, R134a, R125 , A mixed refrigerant with one or more HFC refrigerants selected from R152a, R227ea, R236fa, etc., or a mixed refrigerant obtained by further mixing a hydrocarbon refrigerant such as R290, R600a, etc. or a natural refrigerant such as R744 with the mixed refrigerant. It may be.

  The mixing ratio (mass ratio) of each refrigerant in these mixed refrigerants is HFO refrigerant / HFC refrigerant / hydrocarbon refrigerant or natural refrigerant = 5 to 95/95 to 5/0 to 20, preferably 15 to 85/85 to 15 / It may be 0-10. More specifically, such mixed refrigerants are R444A, R445A, R446A, R447A, R447B, R448A, R449A, R449C, R452B, R454B, R454C, R455A, R457A, R458A, R459A, R459A, R459B, R460B, R461A. R513A etc., but is not limited thereto.

  The refrigerator oil according to the present embodiment is usually present in the refrigerator as a working fluid composition for a refrigerator mixed with a refrigerant. That is, the working fluid composition for a refrigerator according to the present embodiment contains the above-described refrigerator oil and the above-described refrigerant. The content of the refrigerating machine oil in the working fluid composition for a refrigerating machine may be 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 refrigerator oil and the working fluid composition for a refrigerator according to the present embodiment are an air conditioner having a reciprocating or rotary closed type compressor, a refrigerator, an open or closed type car air conditioner, a dehumidifier, a water heater, a freezer It is suitably used in freezers, freezers, vending machines, showcases, refrigerators such as chemical plants, refrigerators having centrifugal compressors, and the like.

  Hereinafter, the present invention will be more specifically described based on examples, but the present invention is not limited to the examples.

Ａ２：下記式（Ａ−１−２）で表される化合物

Ａ３：下記式（Ａ−１−３）で表される化合物

ａ１：トリクレジルホスフェート
ａ２：ジ（ｎ−オクチル）アシッドフォスフェート
Ｂ１：グリシジルネオデカノエート
Ｂ２：２−エチルヘキシルグリシジルエーテルIn Examples and Comparative Examples, a refrigerator oil having the composition described in Tables 1 to 3 (% by mass based on the total amount of the refrigerator oil) was prepared using the following base oils and additives.
(Base oil)
Base oil 1: Polyester of pentaerythritol and a mixed fatty acid of 2-methylpropanoic acid / 3,5,5-trimethylhexanoic acid (mass ratio: 35/65) (Kinematic viscosity at 40 ° C .: 67 .2 mm ² / s, viscosity index: 84)
Base oil 2: ester intermediate obtained by reacting neopentyl glycol (1 mol) and 1,4-butanediol (0.3 mol) with adipic acid (2.4 mol), 2-ethylhexanol (2.4 mol) Mol) is further reacted, and the remaining unreacted product is removed by distillation to obtain a complex ester (kinetic viscosity at 40 ° C .: 68.2 mm ² / s, viscosity index: 144)
Base oil 3: polyethyl vinyl ether (number average molecular weight: 1900, dynamic viscosity at 40 ° C .: 71.0 mm ² / s, dynamic viscosity at 100 ° C .: 8.6 mm ² / s, viscosity index: 89)
Base oil 4: Polyol ester (kinetic viscosity at 40 ° C .: 68 mm) of pentaerythritol and a mixed fatty acid (weight ratio: 50/50) of 2-ethylhexanoic acid / 3,5,5-trimethylhexanoic acid ² / s)
Base oil 5: 3,5,5-trimethylhexanol as an ester intermediate obtained by reacting neopentyl glycol (1 mole) and 1,4-butanediol (0.3 mole) with adipic acid (2.4 mole) Complex ester obtained by further reacting (2.4 mol) and removing the remaining unreacted product by distillation (kinetic viscosity at 40 ° C .: 150 mm ² / s)
Base oil 6: Polyol ester (kinetic viscosity at 40 ° C .: 220 mm ² / of dipentaerythritol and mixed fatty acid of 2-ethylhexanoic acid / 3,5,5-trimethylhexanoic acid (mass ratio: 50/50) s)
Base oil 7: Polyol ester of pentaerythritol and mixed fatty acid of pentanoic acid / 3,5,5-trimethylhexanoic acid (mass ratio: 25/75) (kinetic viscosity at 40 ° C .: 68 mm ² / s)
Base oil 8: polypropylene glycol dimethyl ether (number average molecular weight (Mn): 1000, 40 ° C. kinematic viscosity: 46.0 mm ² / s, viscosity index: 190)
(Additive)
A1: a compound represented by the following formula (A-1-1)

A2: a compound represented by the following formula (A-1-2)

A3: a compound represented by the following formula (A-1-3)

a1: tricresyl phosphate a2: di (n-octyl) acid phosphate B1: glycidyl neodecanoate B2: 2-ethylhexyl glycidyl ether

  The abrasion resistance test shown below was implemented about each refrigerator oil of an Example and a comparative example. The results are shown in Tables 1 to 3.

(Abrasion resistance test)
The abrasion resistance test was performed by a high speed four ball test. The test was performed using SUJ-2 as a hard ball under the conditions of test oil amount 20 mL, test temperature 80 ° C., rotation speed 1200 rpm, load load 294 N, and test time 30 minutes. The evaluation of abrasion resistance used the average value of the abrasion trace diameter (mm) of the fixed ball | bowl.

Moreover, in Example 8, it replaced with the base oil 1, and prepared the refrigerator oil of Examples 10-16 using each following base oil. About these refrigerator oils, when abrasion resistance was evaluated similarly to the above, the effect equivalent to Examples 1-9 was acquired.
Example 10 Base oil 4
(Example 11) Mixed base oil of base oil 1: base oil 4 = 60: 40 (mass ratio) (Example 12) base oil 1: mixed base oil of base oil 5 = 80: 20 (mass ratio) Example 13) Mixed base oil of 5:80:20 (mass ratio) base oil 4: base oil (Example 14) Mixed base oil of 6:80:20 (mass ratio) base oil 4: 80:20 (Example 15) ) Base oil 7
(Example 16) Base oil 8

  Moreover, 1% by mass of tricresyl phosphate which is a regular phosphoric acid ester, and 2,6-di-tert. Further, 0.5% by mass of -butyl-p-cresol (DBPC) was added to prepare refrigerator oils of Examples 17 to 24 respectively. About these refrigerator oils, when abrasion resistance was evaluated similarly to the above, the effect equivalent to Examples 1-9 was acquired.

  The stability test shown below was implemented about Examples 7-9 and Comparative Examples 5 and 6. The results are shown in Table 4.

(Stability test)
According to JIS K2211: 2009 (autoclave test), the stability at the time of refrigerant mixing was evaluated. That is, 30 g of refrigeration oil adjusted to a water content of 1000 ppm is weighed into an autoclave, and a catalyst (iron, copper, aluminum wire, each having an outer diameter of 1.6 mm × length 50 mm) and 30 g of R32 are enclosed. The mixture was heated at a temperature of 175 ° C. for 168 hours. The acid value (the acid value after the test) was measured for each refrigerator oil after the test according to JIS K 2501: 2003.

  Moreover, when stability was evaluated similarly to the above also about the refrigerator oil of Examples 10-24, the effect equivalent to Examples 7-9 was acquired. In addition, in Examples 17 to 24, when the stability was also evaluated in the case where the refrigerant was changed from R32 to HFO-1234yf in the above-mentioned stability test, good stability was shown.

  As described above, the present invention is not limited to the embodiments and examples disclosed in the specification, and can be appropriately modified without departing from the scope and spirit of the invention which can be read from the claims and the specification as a whole. It should be understood that refrigeration oils etc. with such modifications are also included in the technical scope of the present invention.

Claims (6)

Refrigerant oil containing lubricating oil base oil and the compound represented by following formula (A).

[Wherein, R ^a and R ^b each independently represent a monovalent hydrocarbon group, R ^c represents a divalent hydrocarbon group, X represents a polar group, and Z ^a and Z ^b are each independently. Represents an oxygen atom or a sulfur atom. ]   The refrigerator oil according to claim 1, containing at least one oxygenated oil selected from the group consisting of esters and ethers as the lubricant base oil.   The refrigerator oil according to claim 1, further comprising an epoxy compound.   As the epoxy compound, at least one selected from the group consisting of glycidyl ether type epoxy compound, glycidyl ester type epoxy compound, oxirane compound, alkyl oxirane compound, alicyclic epoxy compound, epoxidized fatty acid monoester, and epoxidized vegetable oil The refrigerating machine oil according to claim 3, which contains it.   The refrigerator oil according to claim 3, containing, as the epoxy compound, at least one selected from the group consisting of glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, and alicyclic epoxy compounds.   The refrigerator oil according to any one of claims 1 to 5, wherein the polar group has an oxygen atom.