JP6964586B2 - Refrigerating machine oil - Google Patents

Description

The present invention relates to refrigerating machine oil.

Refrigerators such as refrigerators, car air conditioners, room air conditioners, and vending machines are equipped with a compressor for circulating the refrigerant in the refrigeration cycle. Then, the compressor is filled with refrigerating machine oil for lubricating the sliding member. Refrigerating machine oil is required to have characteristics such as wear resistance and stability.

Refrigerating machine oils generally contain lubricating base oils and additives that are selected according to the required characteristics as described above. Conventionally, as an additive (abrasion resistant agent) for improving abrasion resistance, a normal phosphoric acid ester, an acidic phosphoric acid ester and the like have been used (for example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 11-256182 Japanese Unexamined Patent Publication No. 2000-282076

However, refrigerating machine oil containing a positive phosphoric acid ester or an acidic phosphoric acid ester as an abrasion resistant agent still has room for improvement in terms of abrasion resistance. The acidic phosphoric acid ester exhibits higher wear resistance than the normal phosphoric acid ester, but there may be a problem in terms of stability.

Under such circumstances, the present inventors have focused on improving wear resistance and developed refrigerating machine oil. That is, an object of the present invention is to provide a refrigerating machine oil having excellent wear 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 refrigerating machine oil containing a lubricating oil base oil and a compound represented by the following formula (A).

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

The refrigerating machine oil preferably contains at least one oxygen-containing oil selected from the group consisting of esters and ethers as a lubricating oil base oil.

The refrigerating machine oil preferably further contains an epoxy compound.

The refrigerating machine oil is preferably selected from the group consisting of a glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, an oxylan compound, an alkyloxylan compound, an alicyclic epoxy compound, an epoxidized fatty acid monoester, and an epoxidized vegetable oil. Contains at least one selected.

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

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

According to the present invention, it is possible to provide a refrigerating machine oil having excellent wear resistance.

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 refrigerating machine oil according to one embodiment contains a lubricating oil base oil and a compound represented by the following formula (A).

Wherein represents a monovalent hydrocarbon radical each R ^a and R ^b independently, R ^c represents a divalent hydrocarbon group, X represents a polar group, 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. Examples of hydrocarbon oils include mineral oil-based hydrocarbon oils and synthetic hydrocarbon oils. Examples of oxygen-containing oils include esters, ethers, carbonates, ketones, silicones and polysiloxanes.

Mineral oil-based hydrocarbon oil is a lubricating oil distillate obtained by atmospheric distillation and vacuum distillation of crude oil such as paraffin-based and naphthen-based oil, which is desorbed from the solvent, refined by solvent, refined by hydrogenation, hydrolyzed, and desorbed by solvent. It can be obtained by purification by methods such as brazing, hydrocarbon dewaxing, white clay treatment, and sulfuric acid washing. These purification methods may be used alone or in combination of two or more.

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

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

Specific examples of the alkyl group having 1 to 19 carbon atoms of the alkylbenzene (A) 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. Examples thereof include a group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecil group and an 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 more preferably a branched alkyl group derived from an oligomer of an olefin such as propylene, butene or isobutylene, especially from the point of view of availability.

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

Alkylbenzene (A) may contain only single-structured alkylbenzene, has 1 to 4 alkyl groups having 1 to 19 carbon atoms, and has a total number of carbon atoms of 9 to 19. Alkylbenzene that satisfies the conditions may contain a mixture of alkylbenzenes having different structures.

Specific examples of the alkyl group having 1 to 40 carbon atoms of the alkylbenzene (B) 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, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecil group, icosyl group, henicosyl group, docosyl group, Tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group, triacontyl group, hentoriacontyl group, dotriacontyl group, tritoriacontyl group, tetratriacontyl group, pentatriacontyl group, hexa Examples thereof include a triacontyl group, a heptatriacontyl group, an octatriacontyl group, a nonatriacontyl group and a 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 more preferably a branched alkyl group derived from an oligomer of an olefin such as propylene, butene or isobutylene, especially from the point of view of availability. Alkyl groups are more preferably linear or branched alkyls derived from linear alkylating agents such as linear paraffins, linear α-olefins or halides thereof, from the point of higher flammability. It is a group, more preferably a branched alkyl group.

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

Alkylbenzene (B) may contain only single-structured alkylbenzene, has 1 to 4 alkyl groups having 1 to 40 carbon atoms, and has a total alkyl groups of 20 to 40 carbon atoms. Alkylbenzene that satisfies the conditions may contain a mixture of alkylbenzenes having different structures.

A poly-α-olefin (PAO) is a compound obtained by polymerizing several molecules of a linear olefin having 6 to 18 carbon atoms having a double bond on only one of the terminals and then hydrogenating the polyα-olefin (PAO). The poly-α-olefin may be, for example, an 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, carbonic acid esters, and mixtures thereof. The ester is preferably a polyol ester or a complex ester.

Polyol esters are esters of polyhydric alcohols and fatty acids. As the 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 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 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 mgKOH / g or less, more preferably 5 mgKOH / g or less, still more preferably 3 mgKOH / g or less.

The proportion of fatty acids having 4 to 20 carbon atoms among the fatty acids constituting the polyol ester 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, heptanic 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, 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, and more preferably 2-methylpropanoic acid, 2-methylbutanoic acid, 2-methylpentanoic acid, 2-methylhexanoic acid, 2-ethyl. It is selected from pentanoic acid, 2-methylheptanic acid, 2-ethylhexanoic acid, 3,5,5-trimethylhexanoic acid and 2-ethylhexadecanoic acid, more preferably 2-ethylhexanoic acid and 3,5,5-. Selected from trimethylhexanoic acid.

The fatty acid may contain a fatty acid other than the fatty acid 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, tricosanoic acid, tetracosanoic acid or the like, and may be linear or branched.

As the polyhydric alcohol constituting the polyol ester, a polyhydric alcohol having 2 to 6 hydroxyl groups is preferably used. The polyhydric alcohol preferably has 4 to 12 carbon atoms, more preferably 5 to 10 carbon atoms. The polyhydric alcohol is preferably a hindered such as neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di- (trimethylolpropane), tri- (trimethylolpropane), pentaerythritol, dipentaerythritol. It is an alcohol, and is more preferably pentaerythritol, dipentaerythritol, or a mixed alcohol of pentaerythritol and dipentaerythritol because 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) By adjusting the molar ratio of the polyhydric alcohol to the polybasic acid, an ester intermediate in which some of the carboxyl groups of the polybasic acid remain without esterification is synthesized, and then the remaining carboxyl groups are obtained. Method of esterification with monohydric alcohol (b) By adjusting the molar ratio of polyhydric alcohol to polybasic acid, an ester intermediate in which some of the hydroxyl groups of the polyhydric alcohol remain without esterification is synthesized. Next, a method of esterifying the remaining hydroxyl group with a monohydric fatty acid.

The complex ester obtained by the method (b) above is slightly inferior in stability to the complex ester obtained by the method (a) above because a relatively strong acid is produced when hydrolyzed when used 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 preferably has 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 a monohydric alcohol and a monohydric fatty acid having 2 to 12 carbon atoms.

Examples of the polyhydric alcohol having 2 to 4 hydroxyl groups include neopentyl glycol, trimethylolpropane, pentaerythritol and the like. A polyhydric alcohol having 2 to 4 hydroxyl groups is preferably neopentyl glycol and trimethylol from the viewpoint of ensuring a suitable viscosity when a complex ester is used as a base oil and obtaining good low temperature characteristics. It is selected from propane, and neopentyl glycol is more preferable from the viewpoint of being able to adjust the viscosity widely.

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 dihydric alcohols 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 can be mentioned. The dihydric alcohol is preferably butanediol from the viewpoint of excellent characteristics of the lubricating oil base oil. Examples of butanediol include 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 2,3-butanediol. 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 mol or less, based on 1 mol of the polyhydric alcohol having 2 to 4 hydroxyl groups. It is mol or less, more preferably 0.4 mol or less.

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, and 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, based on 1 mol of the polyhydric alcohol having 2 to 4 hydroxyl groups. It is mol, more preferably 0.6 mol to 2.5 mol.

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

Examples of the ether include polyvinyl ether, polyalkylene glycol, polyphenyl ether, perfluoro ether, and a mixture thereof. The ether is preferably selected from polyvinyl ether and polyalkylene glycol, and more preferably polyvinyl ether.

［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 from each other and represent hydrogen atoms or hydrocarbon groups, respectively, where R ⁴ is a divalent hydrocarbon group or divalent ether bond. It represents an oxygen-containing hydrocarbon group, R ⁵ represents a hydrocarbon group, and m represents an integer of 0 or more. When m is 2 or more, the plurality of R ^4s may be the same or different from each other. ]

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

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

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

The polyvinyl ether may be a copolymer composed of one type selected from the structural units represented by the formula (1), or may be composed of two or more types selected from the structural units represented by the formula (1). It may be a copolymer to be used, or it may be a copolymer composed of a structural unit represented by the formula (1) and another structural unit. Since the polyvinyl ether is a copolymer, the lubricity, the insulating property, the hygroscopic property and the like can be further improved while satisfying the compatibility of the refrigerating machine oil with the refrigerant. At this time, by appropriately selecting the type of the monomer as the raw material, the type of the initiator, the ratio of the structural units in the copolymer, and the like, it is possible to obtain the desired characteristics of the refrigerating machine oil. The copolymer may be either a block copolymer or a random copolymer.

If the polyvinyl ether is a copolymer, the copolymer, the structural unit (1-1) represented and R ⁵ is an alkyl group having 1 to 3 carbon atoms in the above formula (1), the formula ( 1) is represented by and ^{R 5} is 3 to 20 carbon atoms, preferably 3 to 10, and more preferably have a structural unit (1-2) alkyl group having 3 to 8, a. ^{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 It is 5:95 to 95:10, more preferably 20:80 to 90:10, and even more preferably 70:30 to 90:10. When the molar ratio is within the above range, the compatibility with the refrigerant can be further improved, and the hygroscopicity tends to be lowered.

［式（２）中、Ｒ^６〜Ｒ^９は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜２０の炭化水素基を表す。］The polyvinyl ether may be composed of only the structural units represented by the above formula (1), but may be a copolymer further having the structural units 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 or different from each other, and represent hydrogen atoms or hydrocarbon groups having 1 to 20 carbon atoms, respectively. ]

［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 the vinyl ether-based monomer corresponding to the structural unit represented by the formula (1), or the vinyl ether-based 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 a structural unit. As the vinyl ether-based monomer corresponding to the structural unit represented by the formula (1), the monomer represented by the 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) Is shown. ]

Polyvinyl ether preferably has the following terminal structures (A) or (B).

(A) A structure in which one end is represented by the formula (4) or (5) and the other end is represented by the 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 or different from each other, and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and R ⁴¹ has 1 to 10 carbon atoms. It indicates a divalent hydrocarbon group or a divalent ether-bonded oxygen-containing hydrocarbon group, R ⁵¹ indicates a hydrocarbon group having 1 to 20 carbon atoms, and m has the same definition as m in the formula (1). show. When m is 2 or more, the plurality of R ^41s may be the same or different from each other. ]

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

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

［式（６）中、Ｒ^１２，Ｒ^２２及びＲ^３２は互いに同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜８の炭化水素基を示し、Ｒ^４２は炭素数１〜１０の二価の炭化水素基又は二価のエーテル結合酸素含有炭化水素基を示し、Ｒ^５２は炭素数１〜２０の炭化水素基を示し、ｍは式（１）中のｍと同一の定義内容を示す。ｍが２以上の場合には、複数のＲ^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 from each other, and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and R ⁴² has 1 to 10 carbon atoms. It indicates a divalent hydrocarbon group or a divalent ether-bonded oxygen-containing hydrocarbon group, R ⁵² indicates a hydrocarbon group having 1 to 20 carbon atoms, and m has the same definition as m in the formula (1). show. When m is 2 or more, the plurality of R ^42s 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 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 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 polyvinyl ethers (a), (b), (c), (d) and (e) listed below are particularly suitable as the base oil.
(A) It has a structure in which one end is represented by the formula (4) or (5) and the other end is represented by the formula (6) or (7), and R ¹ , R in the formula (1). ² and R ³ are both hydrogen atoms, m is an integer of 0 to 4, R ⁴ is a divalent hydrocarbon group having 2 to ^{4 carbon atoms, and R 5} is a hydrocarbon group having 1 to 20 carbon atoms. ..
(B) It has only the structural unit represented by the formula (1), and has a structure in which 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 all hydrogen atoms, m is an integer of 0 to 4, R ⁴ is a divalent hydrocarbon group having 2 to ^{4 carbon atoms, and R 5} is 1 carbon atom. Polyvinyl ether which is a hydrocarbon group of ~ 20.
(C) It has a structure in which one end is represented by the formula (4) or (5) and the other end is represented by the formula (8), and R ¹ , R ^{2 and R 3 in the formula (1).} 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) It has only the structural unit represented by the formula (1), and has a structure in which one end is represented by the formula (5) and the other end is represented by the formula (8). ^{, R 1} , R ² and R ³ in the formula (1) are all hydrogen atoms, m is an integer of 0 to 4, R ⁴ is a divalent hydrocarbon group having 2 to ^{4 carbon atoms, and R 5} is 1 carbon atom. Polyvinyl ether which is a hydrocarbon group of ~ 20.
(E) A structural unit according to any one of (a), (b), (c) and (d) above, wherein R ⁵ in the formula (1) is a hydrocarbon group having 1 to 3 carbon atoms and the R. ^{A polyvinyl ether having a structural unit in which 5} 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, and preferably 3000 or less, more preferably 2000 or less, still more preferably 1500 or less. When the weight average molecular weight of polyvinyl ether is 500 or more, the lubricity in the coexistence of a refrigerant is excellent. When the weight average molecular weight is 3000 or less, the composition range showing compatibility with the refrigerant is widened under low temperature conditions, and it is possible to suppress poor lubrication of the refrigerant compressor and inhibition of heat exchange in the evaporator.

The number average molecular weight of 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 polyvinyl ether is 500 or more, the lubricity in the coexistence of a refrigerant is excellent. When the number average molecular weight is 3000 or less, the composition range showing compatibility with the refrigerant is widened under low temperature conditions, 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 polyvinyl ether mean the weight average molecular weight and the number average molecular weight (polystyrene (standard sample) conversion value) obtained by GPC analysis, respectively. The weight average molecular weight and the number average molecular weight can be measured as follows, for example.

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). A column with a solvent flow rate of 1 ml / min and an analyzable molecular weight of 100 to 10000 is used, and the analysis is carried out 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, a calibration curve is prepared separately, and the molecular weight of the sample is determined from the obtained retention time.

The degree of unsaturation of 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, 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, 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, still more preferably 3 mgKOH / g or less.

The degree of unsaturation, the peroxide value, and the carbonyl value in the present invention refer to the values measured by the standard oil and fat analysis test method established by the Japan Oil Chemists' Society, respectively. That is, the degree of unsaturatedness in the present invention is determined by reacting a sample with a whistle solution (ICl-acetic acid solution) and leaving it in a dark place, then reducing excess ICl to iodine and titrating the iodine content with sodium thiosulfate. Iodine value is calculated, and this iodine value is converted to 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 generated free iodine with sodium thiosulfate, and converting this free iodine into milliequivalents with respect to 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 generate quinoid ions having color development, measuring the absorbance of this sample at 480 nm, and obtaining cinnamaldehyde as a standard substance in advance. It means a value (weight ppm) converted into the amount of carbonyl based on. The hydroxyl value in the present invention means the hydroxyl value measured according to JIS K0070: 1992.

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

Examples of the polyalkylene glycol include compounds represented by the following formula (9).
R ^α -[(OR ^β ) _f- OR ^γ ] _g (9)
[In formula (9), R ^α represents a residue of a compound having a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms, or 2 to 8 hydroxyl groups, and R ^β represents carbon. Represents an alkylene group of number 2-4, 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 1. Represents an integer of 8. ]

The ^{alkyl group represented by R α} and R ^γ may be linear, branched or cyclic. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms. When the number of carbon atoms 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 and R ^{γ may be linear, branched or cyclic.} The acyl group has preferably 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms. If the number of carbon atoms of the acyl group exceeds 10, the compatibility with the refrigerant may decrease and phase separation may occur.

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 ^{groups represented by a plurality of 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 further 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 an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and further preferably a methyl group. From the viewpoint of ease of production and cost, ^{it is preferable that either one of R α} and R ^γ is an alkyl group (more preferably an alkyl group having 1 to 4 carbon atoms) and the other is a hydrogen atom, and one of them 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 are 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. ^Examples of the repeating unit oxyalkylene group represented by OR β include an oxyethylene group, an oxypropylene group and an oxybutylene group. The oxyalkylene group represented by (OR ^β ) _f may be composed of one kind of oxyalkylene group or two or more kinds of oxyalkylene group.

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 the refrigerant and viscosity-temperature characteristics. It is a coalescence. 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 seizure load and viscosity-temperature characteristics. , More preferably 0.3 to 0.6. From the viewpoint of excellent hygroscopicity and thermal / oxidative stability, EO / (PO + EO) is preferably 0 to 0.5, more preferably 0 to 0.2, and even more preferably 0 (that is, a propylene oxide homopolymer). Is.

f represents the number of repetitions (degree of polymerization) of the oxyalkylene group OR ^{β, and is an integer of 1 to 80.} g is an integer of 1-8. For example, if R ^α is an alkyl or 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 refrigerating machine 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 coexistence of a refrigerant is excellent. When the weight average molecular weight is 3000 or less, the composition range showing compatibility with the refrigerant is widened under low temperature conditions, and it is possible to 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, 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 a refrigerant is excellent. When the number average molecular weight is 3000 or less, the composition range showing compatibility with the refrigerant is widened under low temperature conditions, 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 the weight average molecular weight and the number average molecular weight (polypropylene glycol (standard sample) conversion value) obtained by GPC analysis, respectively. The weight average molecular weight and the number average molecular weight can be measured as follows, for example.

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). A column with a solvent flow rate of 1 ml / min and an analyzable molecular weight of 100 to 10000 is used, and the analysis is carried out 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, a calibration curve is prepared separately, 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 glycols can be synthesized using known methods ("alkylene oxide polymer", Mitsuta Shibata et al., Kaibundo, published 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 so, the polyalkylene glycol represented by the formula (9) can be obtained. When two or more kinds of alkylene oxides are used in the above production process, the obtained polyalkylene glycol may be either a random copolymer or a block copolymer, but tends to be more excellent in oxidative stability and lubricity. From the point of view, it is preferably a block copolymer, and from the point of view that it tends to be 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, still more preferably 20 ppm by weight or less.

The lubricating oil base oil is preferably at least one selected from oxygen-containing oils, and more preferably at least one selected from esters and ethers.

The kinematic viscosity of the lubricating oil base oil at 40 ° C. may be 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 lubricating oil base oil at 40 ° C. may be preferably 1000 mm ² / s or less, more preferably 500 mm ² / s or less, and further preferably 400 mm ² / s or less. The kinematic viscosity of the lubricating oil base oil at 100 ° C. may be preferably 1 mm ² / s or more, and more preferably 2 mm ² / s or more. The kinematic viscosity of the lubricating oil base oil at 100 ° C. may be preferably 100 mm ² / s or less, more preferably 50 mm ² / s or less. The kinematic viscosity in the present invention means the kinematic viscosity measured according to JIS K2283: 2000.

The content of the lubricating oil 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 refrigerating machine 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 of the following formulas (A-1) to (A-3).

In formulas (A-1) to (A-3), ^Ra , R ^b , R ^c and X are synonymous with ^{R a} , R ^b , R ^c and X in formula (A), respectively.

The ^{monovalent hydrocarbon group represented by Ra} and R ^b may have 2 to 18, 2 to 16, 2 to 14, 2 to 12, 2 to 10 or 2 to 8 carbon atoms. The monovalent hydrocarbon group may be a linear or branched alkyl group. The number of carbon atoms of the divalent hydrocarbon group represented by R ^c is may be 1～4,1～3,1～2 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 groups include, 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. It may be either a (COOR) CH ₂ COOH group or a group represented by the following formulas (x-1) to (x-4).

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

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。As a preferred embodiment, the compound represented by the formula (A) may be a compound represented by the following formula (A-4).

Wherein, ^{R d} and ^{R e} each independently represents a linear or branched alkyl group having 2 to 8 carbon atoms, ^{X a} is -OH group, -COOH group or a -COOR 'group (R' is C 1 -C Represents a linear or branched alkyl group of ~ 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 amount of refrigerating machine oil, and is 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. 01-0.1% by mass, 0.01-0.2% by mass, 0.01-1% by mass, 0.02-0.1% by mass, 0.02-0.2% by mass or 0.02- It may be 1% by mass.

The refrigerating machine oil may further contain an epoxy compound. Examples of the epoxy compound include a glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, an oxylan compound, an alkyloxylan compound, an alicyclic epoxy compound, an epoxidized fatty acid monoester, and an epoxidized vegetable oil. 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 represented by the following formula (B-1) or an alkyl glycidyl ether type epoxy compound.

In the formula, R ^f represents an aryl group having 6 to 18 carbon atoms or an alkyl group having 5 to 18 carbon atoms.

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, hexylphenyl glycidyl ether, heptylphenyl glycidyl ether, octylphenyl glycidyl ether, nonylphenyl glycidyl ether, decylphenyl 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), and specifically, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetra. 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 the formula, R ^g represents an aryl group having 6 to 18 carbon atoms, an alkyl group having 5 to 18 carbon atoms, or an alkenyl group having 5 to 18 carbon atoms.

The glycidyl ester type epoxy compound represented by the 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 carbon atoms constituting an epoxy group directly constitute an alicyclic ring.

The alicyclic epoxy compound includes, for example, 1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 3', 4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and bis (3,4-epoxy). Cyclohexylmethyl) adipate, exo-2,3-epoxynorbornane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 2- (7-oxabicyclo [4.1.0] hept-3-yl) -Spiro (1,3-dioxane-5,3'-[7] oxabicyclo [4.1.0] heptane, 4- (1'-methylepoxyethyl) -1,2-epoxy-2-methylcyclohexane, It may be 4-epoxyethyl-1,2-epoxycyclohexane.

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

Examples of the alkyloxylan compound include 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-epoxyheptan, 1,2-epoxyoctane, 1,2-epoxynonane, 1, 2-Epoxy Decane, 1,2-Epoxy Undecane, 1,2-Epoxy Dodecane, 1,2-Epoxy Tridecane, 1,2-Epoxy Tetradecane, 1,2-Epoxy Pentadecane, 1,2-Epoxy Hexadecane, 1, Examples thereof include 2-epoxy heptadecane, 1,2-epoxy octadecane, 1,2-epoxy nonadecan, and 1,2-epoxy icosan.

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

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

When the refrigerating machine oil contains both the compound represented by the formula (A) and the epoxy compound, the refrigerating machine oil has only abrasion resistance as compared with the conventional refrigerating machine oil containing, for example, 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 a glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, and an alicyclic epoxy compound from the viewpoint of achieving both wear resistance and stability, and more preferably. It is at least one selected from a glycidyl ether type epoxy compound and a glycidyl ester type epoxy compound.

From the viewpoint of improving stability, 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 refrigerating machine oil. be. From the viewpoint of improving lubricity, 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 refrigerating machine oil. be.

Refrigerating machine oil may further contain other additives. Examples of other additives include acid scavengers other than epoxy compounds, antioxidants, extreme pressure agents, oily agents, defoamers, metal inactivating agents, and resistance to compounds other than compounds represented by the formula (A). Examples include a wear agent, a viscosity index improver, a pour point lowering agent, and a cleaning dispersant. 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 refrigerating machine oil preferably further contains at least one of the above-mentioned other additives, an antioxidant and an anti-wear agent other than the compound represented by the formula (A). Antioxidants are available in 2,6-di-tert. It may be a phenolic antioxidant such as −butyl-p-cresol or bisphenol A, or an amine-based antioxidant such as alkylphenyl α-naphthylamine or dialkyldiphenylamine. Anti-wear agents other than the compound represented by the formula (A) include phosphorus such as phosphoric acid ester, acidic phosphoric acid ester, thiophosphate ester, amine salt of acidic phosphoric acid ester, chlorinated phosphoric acid ester, and phosphite ester. It may be a system anti-wear agent.

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

The kinematic viscosity of the refrigerating machine oil at 100 ° C. may be preferably 1 mm ² / s or more, more preferably 2 mm ² / s or more. The kinematic viscosity of the refrigerating machine oil at 100 ° C. may be preferably 100 mm ² / s or less, more preferably 50 mm ² / s or less.

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

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

The water content of the refrigerating machine 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 refrigerating machine oil.

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

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

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

Examples of the saturated fluorinated hydrocarbon refrigerant include saturated fluorinated hydrocarbons having 1 to 3 carbon atoms, more preferably 1 to 2 carbon atoms. Specifically, difluoromethane (R32), trifluoromethane (R23), pentafluoroethane (R125), 1,1,2,2-tetrafluoroethane (R134), 1,1,1,2-tetrafluoroethane. (R134a), 1,1,1-trifluoroethane (R143a), 1,1-difluoroethane (R152a), fluoroethane (R161), 1,1,1,2,3,3,3-heptafluoropropane (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 mixtures of two or more thereof can be mentioned.

The saturated fluorocarbon refrigerant is appropriately selected from the above depending on the application and required performance. For example, R32 alone; R23 alone; R134a alone; R125 alone; R134a / R32 = 60 to 80% by mass / 40. ~ 20% by mass mixture; R32 / R125 = 40 ~ 70% by mass / 60-30% by mass; R125 / R143a = 40-60% by mass / 60-40% by mass mixture; R134a / R32 / R125 = 60 Mixture of% by mass / 30% by mass / 10% by mass; mixture of R134a / R32 / R125 = 40 to 70% by mass / 15 to 35% by mass / 5 to 40% by mass; R125 / R134a / R143a = 35 to 55% by mass. A mixture of / 1 to 15% by mass / 40 to 60% by mass is given as 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. / 55% by mass mixture (R410B); R125 / R143a = 50/50% by mass mixture (R507C); R32 / R125 / R134a = 30/10/60% by mass mixture; R32 / R125 / R134a = 23/25 / 52% by mass mixture (R407C); R32 / R125 / R134a = 25/15/60% by mass mixture (R407E); R125 / R134a / R143a = 44/4/52% by mass mixture (R404A) and the like are used. be able to.

The unsaturated fluorinated hydrocarbon (HFO) refrigerant is preferably an unsaturated fluorinated hydrocarbon having 2 to 3 carbon atoms, more preferably a fluoropropene, and even more preferably a fluoropropene having 3 to 5 fluorine numbers. The unsaturated fluorinated hydrocarbon refrigerant is preferably 1,2,3,3,3-pentafluoropropene (HFO-1225ye), 1,3,3,3-tetrafluoropropene (HFO-1234ze), 2, One 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. From the viewpoint of the physical characteristics of the refrigerant, the unsaturated fluorocarbon refrigerant is preferably one or more selected from HFO-1225ye, HFO-1234ze and HFO-1234yf. The unsaturated fluorocarbon 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) or 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 mixtures thereof.

The hydrocarbon refrigerant is preferably a hydrocarbon having 1 to 5 carbon atoms, and 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 them. Can be mentioned. Among these, a hydrocarbon refrigerant gaseous at 25 ° C. and 1 atm is preferably used, and propane, normal butane, isobutane, 2-methylbutane 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 selected from unsaturated hydrocarbon (HFO) refrigerants or one selected from unsaturated hydrocarbon (HFO) refrigerants. A mixed refrigerant of two or more kinds of refrigerants and one or more kinds of refrigerants selected from saturated fluorinated hydrocarbon (HFC) refrigerants, or one kind selected from hydrocarbon refrigerants and natural refrigerants in the mixed refrigerants or It may be a mixed refrigerant in which two or more kinds of refrigerants are further mixed. More specifically, the refrigerants include, for example, one or more HFO refrigerants selected from, for example, HFO-1225ye, HFO-1234ze, HFO-1234yf, HFO-1123, HCFO-1224yd, and R32, R134a, R125. , R152a, R227ea, R236fa, etc., or a mixed refrigerant with one or more HFC refrigerants selected from, or a mixed refrigerant obtained by further mixing a hydrocarbon refrigerant such as R290, R600a, 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 to 10. More specifically, such mixed refrigerants include R444A, R445A, R446A, R447A, R447B, R448A, R449A, R449C, R452B, R454B, R454C, R455A, R456A, R457A, R458A, R459A, R459B, R459A. , R513A, etc., but is not limited thereto.

The refrigerating machine oil according to the present embodiment usually exists in a refrigerating machine in the state of a working fluid composition for a refrigerating machine mixed with a refrigerant. That is, the working fluid composition for a refrigerator according to the present embodiment contains the above-mentioned refrigerating machine oil and the above-mentioned 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 sealed compressor, a refrigerator, an open or closed car air conditioner, a dehumidifier, a water heater, and a freezer. , Refrigerator / refrigerator warehouse, vending machine, showcase, refrigerator in chemical plant, refrigerator with centrifugal compressor, etc.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to 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, refrigerating machine oils having the compositions shown in Tables 1 to 3 (mass% based on the total amount of refrigerating machine oil) were prepared using the base oils and additives shown below.
(Base oil)
Base oil 1: Polyol ester of pentaerythritol and mixed fatty acid (mass ratio: 35/65) of 2-methylpropanoic acid / 3,5,5-trimethylhexanoic acid (kinematic viscosity at 40 ° C: 67) .2 mm ² / s, viscosity index: 84)
Base oil 2: 2-ethylhexanol (2.4 mol) was added to the ester intermediate obtained by reacting neopentyl glycol (1 mol) and 1,4-butanediol (0.3 mol) with adipic acid (2.4 mol). Mol) was further reacted and the remaining unreacted material was removed by distillation to obtain a complex ester (kinematic viscosity at 40 ° C.: 68.2 mm ² / s, viscosity index: 144).
Base oil 3: Polyethyl vinyl ether (number average molecular weight: 1900, kinematic viscosity at 40 ° C: 71.0 mm ² / s, kinematic viscosity at 100 ° C: 8.6 mm ² / s, viscosity index: 89)
Base oil 4: Polyol ester of pentaerythritol and mixed fatty acid (mass ratio: 50/50) of 2-ethylhexanoic acid / 3,5,5-trimethylhexanoic acid (kinematic viscosity at 40 ° C.: 68 mm) ² / s)
Base oil 5: 3,5,5-trimethylhexanol in an ester intermediate obtained by reacting neopentyl glycol (1 mol) and 1,4-butanediol (0.3 mol) with adipic acid (2.4 mol). Complex ester obtained by further reacting (2.4 mol) and removing the remaining unreacted material by distillation (kinematic viscosity at 40 ° C.: 150 mm ² / s).
Base oil 6: Polyol ester of dipentaerythritol and mixed fatty acid (mass ratio: 50/50) of 2-ethylhexanoic acid / 3,5,5-trimethylhexanoic acid (kinematic viscosity at 40 ° C.: 220 mm ² / s)
Base oil 7: Polyol ester of pentaerythritol and mixed fatty acid of pentanoic acid / 3,5,5-trimethylcaproic acid (mass ratio: 25/75) (kinematic 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: Compound represented by the following formula (A-1-1)

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

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

a1: Tricredyl phosphate a2: Di (n-octyl) acid phosphate B1: Glycidyl neodecanoate B2: 2-Ethylhexyl glycidyl ether

The following wear resistance tests were carried out for each of the refrigerating machine oils of Examples and Comparative Examples. The results are shown in Tables 1-3.

(Abrasion resistance test)
The wear resistance test was carried out by a high-speed walk test. Using SUJ-2 as a hard sphere, the test was conducted under the conditions of a test oil amount of 20 mL, a test temperature of 80 ° C., a rotation speed of 1200 rpm, a load of 294 N, and a test time of 30 minutes. For the evaluation of wear resistance, the average value of the wear mark diameter (mm) of the fixed ball was used.

Further, in Example 8, the refrigerating machine oils of Examples 10 to 16 were prepared using the following base oils instead of the base oil 1. When the wear resistance of these refrigerating machine oils was evaluated in the same manner as described above, the same effects as those of Examples 1 to 9 were obtained.
(Example 10) Base oil 4
(Example 11) Base oil 1: Base oil 4 = 60: 40 (mass ratio) mixed base oil (Example 12) Base oil 1: Base oil 5 = 80: 20 (mass ratio) mixed base oil (Example 12) Example 13) Base oil 4: Base oil 5 = 80: 20 (mass ratio) mixed base oil (Example 14) Base oil 4: Base oil 6 = 80: 20 (mass ratio) mixed base oil (Example 15) ) Base oil 7
(Example 16) Base oil 8

Further, in each of the refrigerating machine oils of Examples 8 and 10 to 16, 1% by mass of tricresyl phosphate which is a normal phosphoric acid ester and 2,6-di-tert. Refrigerating machine oils of Examples 17 to 24 were prepared by further adding 0.5% by mass of -butyl-p-cresol (DBPC). When the wear resistance of these refrigerating machine oils was evaluated in the same manner as described above, the same effects as those of Examples 1 to 9 were obtained.

The stability tests shown below were carried out for Examples 7 to 9 and Comparative Examples 5 and 6. The results are shown in Table 4.

(Stability test)
Stability during refrigerant mixing was evaluated in accordance with JIS K2211: 2009 (autoclave test). That is, 30 g of refrigerating machine oil having a water content adjusted to 1000 ppm is weighed in an autoclave, and a catalyst (iron, copper, aluminum wire, each having an outer diameter of 1.6 mm × length of 50 mm) and 30 g of R32 are sealed. , Heated at a temperature of 175 ° C. for 168 hours. The acid value (post-test acid value) of each refrigerating machine oil after the test was measured according to JIS K2501: 2003.

Further, when the stability of the refrigerating machine oils of Examples 10 to 24 was evaluated in the same manner as described above, the same effect as that of Examples 7 to 9 was obtained. In addition, with respect to Examples 17 to 24, when the stability when the refrigerant was changed from R32 to HFO-1234yf was also evaluated in the above 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 as long as it does not contradict the gist or idea of the invention that can be read from the claims and the entire specification. , Refrigerating machine oil, etc. with such changes must also be understood as being included in the technical scope of the present invention.

Claims (5)

Lubricating oil A refrigerating machine oil containing a base oil and a compound represented by the following formula (A-4).

Wherein represents a linear or branched alkyl group of ^{R d} and ^{R e} 2 to 8 carbon atoms each independently, ^{X a} is -COOH or -COOR 'group (R' is from 1 to 8 carbon atoms Represents a linear or branched alkyl group). ] The refrigerating machine oil according to claim 1, which contains at least one oxygen-containing oil selected from the group consisting of esters and ethers as the lubricating oil base oil. The refrigerating machine oil according to claim 1 or 2, further containing an epoxy compound. As the epoxy compound, at least one selected from the group consisting of a glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, an oxylan compound, an alkyloxylan compound, an alicyclic epoxy compound, an epoxidized fatty acid monoester, and an epoxidized vegetable oil is used. The refrigerating machine oil according to claim 3, which is contained. The refrigerating machine oil according to claim 3, wherein the epoxy compound contains at least one selected from the group consisting of a glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, and an alicyclic epoxy compound.