JP2007262208A - Refrigerator oil composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerator oil capable of sufficiently lowering both of the static friction coefficient and the dynamic friction coefficient in a sliding part of a refrigerant compressor, etc. <P>SOLUTION: The refrigerator oil composition comprises a prescribed lubricating oil base oil and an ester of a carboxylic acid containing hydroxycarboxylic acid with an alcohol. The refrigerator oil composition can reduce both of the starting electric power and the electric power consumption during operation and attain energy saving in high level, because the oil composition can sufficiently reduce both of the static friction coefficient and the dynamic friction coefficient in the sliding part of the refrigerant compressor, etc. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a refrigerator oil composition.

  Refrigerating machine oils suitable for alternative refrigerants are being studied as refrigerant alternatives to ozone-depleting fluorocarbons based on the Montreal Protocol are being promoted.

  For example, Patent Documents 1 to 3 listed below disclose a hydrofluorocarbon (HFC) refrigerant refrigerating machine oil that uses a polyol ester or ether-based synthetic oil that is compatible with the HFC refrigerant.

  In addition, as a refrigerating machine oil having improved characteristics such as frictional properties and wear resistance, the following Patent Document 4 discloses a refrigerating machine oil containing a predetermined amount of a thiadiazole compound and dibenzyl disulfide in a predetermined lubricating base oil. Has been.

Further, as a refrigerating machine oil having both sufficiently improved wear resistance and friction characteristics, Patent Document 5 below discloses a refrigerating machine oil containing a predetermined amount of polyalkylene glycol in an ester base oil.
Japanese National Patent Publication No. 3-505602 Japanese Patent Laid-Open No. 3-128992 JP-A-3-200955 JP 2004-67836 A JP 2005-54063 A

  By the way, in recent years, in the field of refrigerating and air-conditioning equipment such as air conditioners and refrigerators, interest in energy saving has been increased, and studies are being made to reduce power consumption during startup and during operation.

  Among these, as means for reducing power consumption during operation, for example, there is a method of reducing energy loss by adding a friction modifier to refrigeration oil to lower the dynamic friction coefficient in the sliding portion. From such a viewpoint, although the thiadiazole compound and the dibenzyl disulfide are used in the said patent document 4, the friction reduction effect obtained when these additives are used is not necessarily enough. In Patent Document 5, polyalkylene glycol is contained in the ester base oil to reduce the dynamic friction coefficient inside the compressor, but the effect is not always sufficient.

  Moreover, as means for reducing the starting power, for example, there is a method of improving the compression efficiency by operating the refrigerant compressor at low speed rotation by inverter control and reducing the energy loss. If the rotational speed of the compressor changes greatly due to the change in value, the frictional force also increases accordingly. Therefore, in order to reduce the starting power, it is desirable to use a refrigerating machine oil that can reduce the coefficient of static friction, but from this point of view, studies for improving the friction characteristics of the refrigerating machine oil have not been sufficiently performed.

  The present invention has been made in view of such circumstances, and can sufficiently reduce both the static friction coefficient and the dynamic friction coefficient in the sliding portion of the refrigerant compressor or the like, thereby achieving a high level of energy saving. An object of the present invention is to provide a refrigerating machine oil that can be used.

  In order to solve the above-mentioned problems, the present invention provides a refrigerating machine oil composition comprising a predetermined lubricating oil base oil and an ester of a carboxylic acid containing hydroxycarboxylic acid and an alcohol.

  According to the refrigerating machine oil composition of the present invention, by containing the predetermined lubricating base oil and the specific ester compound, both the static friction coefficient and the dynamic friction coefficient in the sliding portion of the refrigerant compressor or the like are sufficiently obtained. Therefore, it is possible to reduce both the starting power and the power consumption during operation, and to achieve a high level of energy saving.

  According to the present invention, there is provided a refrigerating machine oil composition capable of sufficiently reducing both the static friction coefficient and the dynamic friction coefficient in a sliding portion such as a refrigerant compressor and achieving a high level of energy saving. The

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

  The base oil used in the present invention may be either mineral oil or synthetic oil, or may be a mixed base oil of mineral oil and synthetic oil.

  As mineral oils, for example, solvent degreasing, solvent extraction, hydrocracking of lubricating oil fractions obtained by atmospheric distillation and vacuum distillation of paraffinic, intermediate or naphthenic crude oils , Paraffinic mineral oil or naphthenic mineral oil obtained by applying a combination of one or more kinds of purification means such as solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid washing, and clay treatment as appropriate.

  Among these mineral oils, it is preferable to use highly refined mineral oil (hereinafter referred to as “highly refined mineral oil”) from the viewpoint of superior thermal stability. Specific examples of highly refined mineral oils include distillate oil obtained by atmospheric distillation of paraffinic crude oil, intermediate crude oil or naphthenic crude oil, or by distilling residual oil of atmospheric distillation under reduced pressure according to a conventional method. Refined oil obtained by refining; deep dewaxed oil obtained by further deep dewaxing after refining; hydrotreated oil obtained by hydrotreating, and the like.

  The purification method in the purification step is not particularly limited, and a conventionally known method can be used. For example, (a) hydrogenation treatment, (b) dewaxing treatment (solvent dewaxing or hydrodehydration). A method of performing any one of wax), (c) solvent extraction treatment, (d) alkali washing or sulfuric acid washing treatment, and (e) clay processing alone or in combination of two or more in an appropriate order. Can be mentioned. It is also effective to repeat any one of the processes (a) to (e) in a plurality of stages. More specifically, (i) a method of hydrotreating distillate oil, or a method of performing alkali washing or sulfuric acid washing treatment after hydrogenation treatment; (ii) dehydrating oil after hydrogenation treatment. A method of wax treatment; (iii) a method of subjecting the distillate to a hydrogenation treatment after solvent extraction; (iv) subjecting the distillate to a two-stage or three-stage hydrotreatment, or subsequent alkali washing or sulfuric acid (V) A method of dewaxing again to obtain a deep dewaxed oil after the above-described treatments (i) to (iv), and the like.

  Among highly refined mineral oils obtained by the above refining method, naphthenic mineral oils and mineral oils obtained by deep dewaxing are preferred from the viewpoints of low temperature fluidity and no wax precipitation at low temperatures. This deep dewaxing process is usually performed by a solvent dewaxing process under severe conditions, a catalytic dewaxing process using a zeolite catalyst, or the like.

  Further, the non-aromatic unsaturation (unsaturation) of such highly refined mineral oil is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 1% by mass or less, and particularly preferably 0.1% by mass. % Or less. When the non-aromatic unsaturated content exceeds 10% by mass, sludge is likely to be generated, and as a result, the expansion mechanism such as a capillary constituting the refrigerant circulation system tends to be blocked.

  On the other hand, synthetic oils used in the present invention include hydrocarbon oils such as olefin polymers, naphthalene compounds, alkylbenzenes; esters, polyalkylene glycols, polyvinyl ethers, ketones, polyphenyl ethers, silicones, polysiloxanes, perfluoroethers. And other oxygen-containing synthetic oils.

  Examples of the olefin polymer include those obtained by polymerizing an olefin having 2 to 12 carbon atoms, and those obtained by hydrogenating a compound obtained by the polymerization, such as polybutene, polyisobutene, and α having 5 to 12 carbon atoms. -Oligomeric oligomers (poly-alpha olefins), ethylene-propylene copolymers, and hydrogenated products thereof are preferably used.

  The production method of the olefin polymer is not particularly limited, and can be produced by various known methods. For example, poly α-olefin is produced by using α-olefin produced from ethylene as a raw material and treating it with a known polymerization method such as Ziegler catalyst method, radical polymerization method, aluminum chloride method, boron fluoride method and the like. .

  The naphthalene compound is not particularly limited as long as it has a naphthalene skeleton, but has 1 to 4 alkyl groups having 1 to 10 carbon atoms and has a total carbon content of alkyl groups from the viewpoint of excellent compatibility with the refrigerant. Those having 1 to 10 carbon atoms are preferred, those having 1 to 3 alkyl groups having 1 to 8 carbon atoms and those having 3 to 8 carbon atoms in total are more preferred.

  Specific examples of the alkyl group having 1 to 10 carbon atoms that the naphthalene compound has include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a linear or branched butyl group, a linear or branched group. A branched pentyl group, a linear or branched hexyl group, a linear or branched heptyl group, a linear or branched octyl group, a linear or branched nonyl group, Examples thereof include a linear or branched decyl group.

  In addition, when using a naphthalene compound, the compound of a single structure may be used independently, and 2 or more types of the compounds from which a structure differs may be used in combination.

  Moreover, the manufacturing method in particular of the said naphthalene compound is not restrict | limited, It can manufacture with a various well-known method. Examples of this include, for example, hydrocarbon halides having 1 to 10 carbon atoms, olefins having 2 to 10 carbon atoms, or styrenes having 8 to 10 carbon atoms, sulfuric acid, phosphoric acid, silicotungstic acid, hydrofluoric acid, etc. And a method of adding to naphthalene in the presence of an acid catalyst such as Friedel-Crafts catalyst which is a solid acidic substance such as mineral acid, acidic clay and activated clay, or a metal halide such as aluminum chloride and zinc chloride.

  Although it does not specifically limit as alkylbenzene concerning this invention, From the point which is excellent in compatibility with a refrigerant | coolant, it has 1-4 C1-C40 alkyl groups, and the total carbon number of an alkyl group is 1-40. Some are preferable, and those having 1 to 4 alkyl groups having 1 to 30 carbon atoms and having 3 to 30 carbon atoms in total are more preferable.

  Specific examples of the alkyl group having 1 to 40 carbon atoms that the alkylbenzene has include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a linear or branched butyl group, a linear or branched group. Pentyl group, linear or branched hexyl group, linear or branched heptyl group, linear or branched octyl group, linear or branched nonyl group, straight Linear or branched decyl group, linear or branched undecyl group, linear or branched dodecyl group, linear or branched tridecyl group, linear or branched Tetradecyl group, linear or branched pentadecyl group, linear or branched hexadecyl group, linear or branched heptadecyl group, linear or branched octadecyl group, linear -Like or branched nonadecyl group, linear or branched icosyl group, linear or branched Straight chain or branched docosyl group, linear or branched tricosyl group, linear or branched tetracosyl group, linear or branched pentacosyl group, straight chain Linear or branched hexacosyl group, linear or branched heptacosyl group, linear or branched octacosyl group, linear or branched nonacosyl group, linear or branched Triacontyl group, linear or branched hentriacontyl group, linear or branched dotriacontyl group, linear or branched tritriacontyl group, linear or branched tetra Triacontyl group, linear or branched pentatriacontyl group, linear or branched hexatriacontyl group, linear or branched heptatriacontyl group, linear Or branched octatriacontyl group, linear or branched Nona triacontyl group, such as straight or branched tetracontyl group (including all isomers).

  The alkyl group may be either linear or branched, but is preferably a linear alkyl group from the viewpoint of compatibility with the organic material used in the refrigerant circulation system. On the other hand, branched alkyl groups are preferable from the viewpoint of refrigerant compatibility, thermal stability, lubricity, etc., and branched alkyls derived from oligomers of olefins such as propylene, butene and isobutylene are particularly preferable from the viewpoint of availability. Groups are more preferred.

  In addition, when using alkylbenzene, the compound of a single structure may be used independently, and 2 or more types of the compounds from which a structure differs may be used in combination.

  Although the manufacturing method of the said alkylbenzene is arbitrary and is not limited at all, For example, it can manufacture by the synthesis method shown below.

  Specific examples of the aromatic compound used as a raw material include benzene, toluene, xylene, ethylbenzene, methylethylbenzene, diethylbenzene, and mixtures thereof. Further, as the alkylating agent, a linear or branched olefin having 6 to 40 carbon atoms obtained by polymerization of lower monoolefin (preferably propylene) such as ethylene, propylene, butene, isobutylene; wax, heavy oil, C6-C40 linear or branched olefins obtained by pyrolysis of petroleum fractions, polyethylene, polypropylene, etc .; n-paraffins are separated from petroleum fractions such as kerosene, light oil, etc. It is possible to use a linear olefin having 9 to 40 carbon atoms, a mixture of these, and the like obtained by converting into a carbon atom.

  In addition, when the aromatic compound and the alkylating agent are reacted, Friedel-Crafts type catalysts such as aluminum chloride and zinc chloride, sulfuric acid, phosphoric acid, silicotungstic acid, hydrofluoric acid, activated clay, etc. Conventionally known alkylation catalysts such as acidic catalysts can be used.

  Examples of the esters include aromatic esters, dibasic acid esters, polyol esters, complex esters, carbonate esters, and mixtures thereof.

  Examples of such aromatic esters include 1 to 6 valent, preferably 1 to 4 valent, more preferably 1 to 3 valent aromatic carboxylic acids, and aliphatic alcohols having 1 to 18 carbon atoms, preferably 1 to 12 carbon atoms. Examples include esters. Specific examples of the monovalent to hexavalent aromatic carboxylic acid include benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, and mixtures thereof. Further, the aliphatic alcohol having 1 to 18 carbon atoms may be linear or branched, and specifically, methanol, ethanol, linear or branched propanol, Linear or branched butanol, linear or branched pentanol, linear or branched hexanol, linear or branched heptanol, linear or branched octanol , Linear or branched nonanol, linear or branched decanol, linear or branched undecanol, linear or branched dodecanol, linear or branched tridecanol Linear or branched tetradecanol, linear or branched pentadecanol, linear or branched hexadecanol, linear or branched heptadecanol, straight Chain or branched octadecanol and these Mixtures thereof, and the like.

  Specific examples of the aromatic ester obtained by using the aromatic compound and the aliphatic alcohol include dibutyl phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, didecyl phthalate, and didodecyl phthalate. , Ditridecyl phthalate, tributyl trimellitic acid, tri (2-ethylhexyl) trimellitic acid, trinonyl trimellitic acid, tridecyl trimellitic acid, tridodecyl trimellitic acid, and tritridecyl trimellitic acid. Of course, when a divalent or higher valent aromatic carboxylic acid is used, it may be a simple ester composed of one kind of aliphatic alcohol, or a complex ester composed of two or more kinds of aliphatic alcohol. May be.

  Examples of the dibasic acid ester include 5 to 10 carbon atoms such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,2-cyclohexanedicarboxylic acid, and 4-cyclohexene-1,2-dicarboxylic acid. A linear or cyclic aliphatic dibasic acid such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, etc. A chain or branched ester with a monohydric alcohol having 1 to 15 carbon atoms and a mixture thereof are preferably used, and more specifically, ditridecyl glutarate, di2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, The 2 Ethylhexyl sebacate, diester of 1,2-cyclohexanedicarboxylic acid and monohydric alcohol having 4 to 9 carbon atoms, diester of 4-cyclohexene-1,2-dicarboxylic acid and monohydric alcohol having 4 to 9 carbon atoms, and these And the like.

  As the polyol ester, an ester of a polyol having 3 to 20 diols or hydroxyl groups and a fatty acid having 6 to 20 carbon atoms is preferably used. Specific examples of the diol include ethylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, , 5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3 -Propanediol, 2,2-diethyl-1,3-propanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecane Diol etc. are mentioned. Specific examples of the polyol include trimethylolethane, trimethylolpropane, trimethylolbutane, di- (trimethylolpropane), tri- (trimethylolpropane), pentaerythritol, di- (pentaerythritol), tri- ( Pentaerythritol), glycerin, polyglycerin (glycerin 2-20 mer), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerin condensate, polyvalent alcohols such as adonitol, arabitol, xylitol, mannitol, xylose Arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, raffinose, gel Chianosu, sugars and their partial etherification such as melezitose, and methyl glucoside (glycoside) and the like. Among these, as the polyol, neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), pentaerythritol, di- (pentaerythritol), tri Hindered alcohols such as-(pentaerythritol) are preferred.

  In the fatty acid used in the polyol ester, the carbon number is not particularly limited, but those having 1 to 24 carbon atoms are usually used. Among the fatty acids having 1 to 24 carbon atoms, those having 3 or more carbon atoms are preferable from the viewpoint of lubricity, those having 4 or more carbon atoms are more preferable, those having 5 or more carbon atoms are further preferable, and those having 10 or more carbon atoms. Is particularly preferred. Moreover, from a compatibility point with a refrigerant | coolant, a C18 or less thing is preferable, a C12 or less thing is more preferable, and a C9 or less thing is further more preferable.

  The fatty acid may be either a linear fatty acid or a branched fatty acid, but a linear fatty acid is preferable from the viewpoint of lubricity, and a branched fatty acid is preferable from the viewpoint of hydrolysis stability. . Furthermore, the fatty acid may be either a saturated fatty acid or an unsaturated fatty acid.

  Specific examples of fatty acids include pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid , Nonadecanoic acid, icosanoic acid, oleic acid, and the like. These fatty acids may be either linear fatty acids or branched fatty acids, and furthermore, fatty acids (neo) whose α carbon atom is a quaternary carbon atom. Acid). Among these, valeric acid (n-pentanoic acid), caproic acid (n-hexanoic acid), enanthic acid (n-heptanoic acid), caprylic acid (n-octanoic acid), pelargonic acid (n-nonanoic acid), caprin Acid (n-decanoic acid), oleic acid (cis-9-octadecenoic acid), isopentanoic acid (3-methylbutanoic acid), 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid and 3,5,5 5-Trimethylhexanoic acid is preferably used.

  In addition, as long as it has two or more ester groups, the polyol ester according to the present invention may be a partial ester in which some of the hydroxyl groups of the polyol remain without being esterified. May be an esterified complete ester, or a mixture of a partial ester and a complete ester, but is preferably a complete ester.

  The complex ester is an ester of a fatty acid and a dibasic acid, and a monohydric alcohol and a polyol. As the fatty acid, dibasic acid, monohydric alcohol and polyol, in the description of the dibasic acid ester and the polyol ester, The exemplified fatty acids, dibasic acids, monohydric alcohols and polyols can be used.

Carbonic acid ester is represented by the following formula (1):
-O-CO-O- (1)
It is a compound which has the carbonate ester bond represented by these. The number of carbonate ester bonds represented by the above formula (1) may be one per molecule or two or more.

  As alcohol which comprises carbonate ester, the monohydric alcohol illustrated by the description of the said dibasic acid ester and polyol ester, a polyol, etc., and what added polyglycol to polyglycol and a polyol can be used. Moreover, you may use the compound obtained from a carbonic acid and a fatty acid and / or a dibasic acid.

  As a matter of course, when an ester is used, a compound having a single structure may be used alone, or two or more compounds having different structures may be used in combination.

  Among the above esters, dibasic acid ester, polyol ester, and carbonate ester are preferable because of excellent compatibility with the refrigerant.

  Furthermore, among dibasic acid esters, alicyclic dicarboxylic acid esters such as 1,2-cyclohexanedicarboxylic acid and 4-cyclohexene-1,2-dicarboxylic acid are compatible with refrigerants, and are stable in heat and hydrolysis. From the point of view, it is more preferable.

  Specific examples of the dibasic acid ester preferably used in the present invention include at least one monohydric alcohol selected from the group consisting of butanol, pentanol, hexanol, heptanol, octanol and nonanol, and 1,2-cyclohexanedicarboxylic acid. , Dibasic acid esters obtained from at least one dibasic acid selected from the group consisting of 4-cyclohexene-1,2-dicarboxylic acid, and mixtures thereof.

  In the dibasic acid ester according to the present invention, the low-temperature characteristics of the refrigerating machine oil composition and the compatibility with the refrigerant tend to be improved, so that there are two or more monohydric alcohols constituting the dibasic acid ester. It is preferable. The dibasic acid ester composed of two or more monohydric alcohols is a mixture of two or more esters of a dibasic acid and one alcohol, and a dibasic acid and two or more mixed alcohols. These esters are included.

  Among polyol esters, since they are more excellent in hydrolytic stability, neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), penta More preferred are esters of hindered alcohols such as erythritol, di- (pentaerythritol), tri- (pentaerythritol), more preferred are esters of neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane and pentaerythritol, The ester of pentaerythritol is most preferred because it is particularly excellent in compatibility with the refrigerant and hydrolytic stability.

  Specific examples of the polyol ester preferably used in the present invention include valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, From the group consisting of at least one fatty acid selected from the group consisting of 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid, and neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane and pentaerythritol. Examples include diesters, triesters, tetraesters and mixtures thereof obtained from at least one selected alcohol.

  In the polyol ester concerning this invention, since the low temperature characteristic of a refrigerating machine oil composition and the compatibility with a refrigerant | coolant tend to improve, it is preferable that the fatty acid which comprises a polyol ester is 2 or more types. The polyol ester composed of two or more fatty acids includes a mixture of two or more esters of polyol and one fatty acid, and an ester of a polyol and two or more mixed fatty acids. .

Among the carbonic acid esters, the following general formula (2):
^{_{(X 1 O) b -B- [}} O- (A 1 O) c -CO-O- (A 2 O) d -Y 1] a (2)
Wherein (2), ^{X 1} is a hydrogen atom, an alkyl group, a cycloalkyl group or the following general formula (3):
Y ^2- (OA ³ ) _e − (3)
(In formula (3), Y ² represents a hydrogen atom, an alkyl group or a cycloalkyl group, A ³ represents an alkylene group having 2 to 4 carbon atoms, and e represents an integer of 1 to 50)
A ¹ and A ² may be the same or different and each represents an alkylene group having 2 to 4 carbon atoms; Y ¹ represents a hydrogen atom, an alkyl group or a cycloalkyl group; Represents a residue of a compound having 3 to 20 hydroxyl groups, a represents 1 to 20, b represents an integer of 0 to 19 and a + b of 3 to 20, c represents an integer of 0 to 50, d Represents an integer of 1 to 50]
What has the structure represented by these is preferable.

In the above formula (2), X ¹ represents a hydrogen atom, an alkyl group, a cycloalkyl group or a group represented by the above formula (3). Although carbon number of an alkyl group here is not restrict | limited in particular, Usually, 1-24, Preferably it is 1-18, More preferably, it is 1-12. The alkyl group may be linear or branched.

  Specific examples of the alkyl group having 1 to 24 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, linear chain Or a branched pentyl group, a linear or branched hexyl group, a linear or branched heptyl group, a linear or branched octyl group, a linear or branched nonyl group, a linear or branched decyl group, a linear or branched Branched undecyl group, linear or branched dodecyl group, linear or branched tridecyl group, linear or branched tetradecyl group, linear or branched pentadecyl group, linear or branched hexadecyl group, linear or branched heptadecyl Group, linear or branched octadecyl group, linear or branched nonadecyl group, linear or branched icosyl group, linear or branched heicosyl group, linear or branched docosyl group, linear or branched tricosyl group, Linear or branched tet Cosyl group, and the like.

  Specific examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group.

The alkylene group having 2 to 4 carbon atoms represented by A ³ in the formula (2) include an ethylene group, a propylene group, trimethylene group, butylene group, tetramethylene group, 1-methyltrimethylene group , 2-methyltrimethylene group, 1,1-dimethylethylene group, 1,2-dimethylethylene group and the like.

Y ² in the above formula (2) represents a hydrogen atom, an alkyl group or a cycloalkylalkyl group. Although carbon number of an alkyl group here is not restrict | limited in particular, Usually, 1-24, Preferably it is 1-18, More preferably, it is 1-12. The alkyl group may be linear or branched. Examples of the alkyl group having 1 to 24 carbon atoms include the alkyl groups exemplified in the description of X ¹ above.

  Specific examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group.

Among the groups represented by Y ² , a hydrogen atom or an alkyl group having 1 to 12 carbon atoms is preferable, and a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso group. -Butyl group, sec-butyl group, tert-butyl group, n-pentyl group, iso-pentyl group, neo-pentyl group, n-hexyl group, iso-hexyl group, n-heptyl group, iso-heptyl group, n -Of the octyl group, iso-octyl group, n-nonyl group, iso-nonyl group, n-decyl group, iso-decyl group, n-undecyl group, iso-undecyl group, n-dodecyl group or iso-dodecyl group It is more preferable that it is either. E represents an integer of 1 to 50.

In addition, the group represented by X ¹ is preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a group represented by the general formula (3), and includes a hydrogen atom, a methyl group, an ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, iso-pentyl group, neo-pentyl group, n-hexyl group, iso-hexyl group, n-heptyl group, iso-heptyl group, n-octyl group, iso-octyl group, n-nonyl group, iso-nonyl group, n-decyl group, iso-decyl group, n-undecyl group, It is more preferably any one of an iso-undecyl group, an n-dodecyl group, an iso-dodecyl group, or a group represented by the general formula (3).

  Specific examples of the compound having B as a residue and having 3 to 20 hydroxyl groups include the aforementioned polyols.

A ¹ and A ² may be the same or different and each represents an alkylene group having 2 to 4 carbon atoms. Specific examples of the alkylene group include ethylene, propylene, trimethylene, butylene, tetramethylene, 1-methyltrimethylene, 2-methyltrimethylene, 1,1-dimethylethylene, 1 , 2-dimethylethylene group and the like.

Y ¹ represents a hydrogen atom, an alkyl group or a cycloalkyl group. Although carbon number of an alkyl group here is not restrict | limited in particular, Usually, 1-24, Preferably it is 1-18, More preferably, it is 1-12. The alkyl group may be linear or branched. Specific examples of the alkyl group having 1 to 24 carbon atoms include the alkyl groups exemplified in the description of X ¹ .

  Specific examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and the like.

Among these, the group represented by Y ¹ is preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and includes a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, n -Butyl group, iso-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, iso-pentyl group, neo-pentyl group, n-hexyl group, iso-hexyl group, n-heptyl group, iso -Heptyl group, n-octyl group, iso-octyl group, n-nonyl group, iso-nonyl group, n-decyl group, iso-decyl group, n-undecyl group, iso-undecyl group, n-dodecyl group or iso -More preferably, it is one of dodecyl groups.

  In the above formulas (2) and (3), c, d and e represent the degree of polymerization of the polyoxyalkylene chain, but the polyoxyalkylene chains in the molecule may be the same or different. In addition, when the carbonic acid ester represented by the above formula (2) has a plurality of different polyoxyalkylene chains, there is no particular limitation on the polymerization mode of the oxyalkylene group, and block copolymerization is performed even if random copolymerization is performed. Also good.

  The method for producing the carbonate ester used in the present invention is arbitrary. For example, a polyalkylene glycol polyol ether is produced by adding an alkylene oxide to a polyol compound, and this and chloroformate are mixed with sodium hydroxide, hydroxide. It can be obtained by reacting at 0 to 30 ° C. in the presence of an alkali metal hydroxide such as potassium, an alkali metal alkoxide such as sodium methoxide or sodium ethoxide, or an alkali such as metal sodium. Or polyalkylene glycol polyol ether, carbonic acid diester, carbon dioxide such as phosgene, alkali metal hydroxide such as sodium hydroxide and potassium hydroxide, alkali metal alkoxide such as sodium methoxide and sodium ethoxide or metal sodium It can be obtained by reacting at 80 to 150 ° C. in the presence of an alkali such as. Thereafter, the free hydroxyl group is etherified as necessary.

  By-products and unreacted materials may be removed by purifying the product obtained from the above raw materials, but a small amount of by-products and unreacted materials impairs the excellent performance of the lubricating oil of the present invention. Unless it exists, there is no problem even if it exists.

In the present invention, when a carbonate ester is used, a compound having a single structure may be used alone, or two or more compounds having different structures may be used in combination. The molecular weight of the carbonate ester according to the present invention is not particularly limited, but the number average molecular weight is preferably 200 to 4000, more preferably 300 to 3000, from the viewpoint of further improving the hermeticity of the compressor. More preferred. Furthermore, the kinematic viscosity of such carbonic acid ester in the present invention, preferably at 100 ° C. is 2~150mm ² / s, more preferably 4~100mm ² / s.

Examples of the polyoxyalkylene glycol used in the lubricating oil of the present invention include the following general formula (4):
R ¹ - ^[(OR 2) _f -OR ^3] _g (4)
[In Formula (4), R ¹ 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 ² represents the number of carbon atoms. Represents an alkylene group having 2 to 4, R ³ 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 8 Represents an integer]
The compound represented by these is mentioned.

In the general formula (4), the alkyl group represented by R ¹ and R ³ may be linear, branched or cyclic. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a linear or branched butyl group, a linear or branched pentyl group, a linear or branched group. Hexyl group, linear or branched heptyl group, linear or branched octyl group, linear or branched nonyl group, linear or branched decyl group, cyclopentyl Group, cyclohexyl group and the like. If the alkyl group has more than 10 carbon atoms, the compatibility with the refrigerant is lowered, and phase separation tends to occur. The carbon number of a preferable alkyl group is 1-6.

Moreover, the alkyl group part of the acyl group represented by R ¹ and R ³ may be linear, branched, or cyclic. Specific examples of the alkyl group portion of the acyl group include those having 1 to 9 carbon atoms among the alkyl groups exemplified as the specific examples of the alkyl group. When the number of carbon atoms in the acyl group exceeds 10, compatibility with the refrigerant may be reduced, and phase separation may occur. A preferable acyl group has 2 to 6 carbon atoms.

When the groups represented by R ¹ and R ³ are both alkyl groups or are both acyl groups, the groups represented by R ¹ and R ³ may be the same or different. Further, when g is 2 or more, the groups represented by a plurality of R ¹ and R ³ in the same molecule may be the same or different.

When the group represented by R ¹ is a residue of a compound having 2 to 8 hydroxyl groups, this compound may be a chain or a cyclic one. Specific examples of the compound having two hydroxyl groups include ethylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,2-butanediol, and 2-methyl-1,3-propanediol. 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 1,7-heptanediol, 2-methyl-2-propyl-1 , 3-propanediol, 2,2-diethyl-1,3-propanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12 -Dodecanediol etc. are mentioned.

  Specific examples of the compound having 3 to 8 hydroxyl groups include trimethylolethane, trimethylolpropane, trimethylolbutane, di- (trimethylolpropane), tri- (trimethylolpropane), pentaerythritol, -(Pentaerythritol), tri- (pentaerythritol), glycerol, polyglycerol (glycerin 2-6 mer), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerol condensate, adonitol, arabitol, xylitol , Polyhydric alcohols such as mannitol, xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, skull Scan, raffinose, gentianose, saccharides such as rhamnose, and their partially etherified products, and include methyl glucoside (glycoside) and the like.

Among the polyoxyalkylene glycols represented by the general formula (4), at least one of R ¹ and R ³ is preferably an alkyl group (more preferably an alkyl group having 1 to 4 carbon atoms), particularly A methyl group is preferred from the viewpoint of refrigerant compatibility. Furthermore, from the viewpoint of thermal and chemical stability, it is preferable that both R ¹ and R ³ are alkyl groups (more preferably, alkyl groups having 1 to 4 carbon atoms), and particularly that both are methyl groups. Is preferred. From the viewpoint of ease of production and cost, it is preferable that either R ¹ or R ³ is an alkyl group (more preferably an alkyl group having 1 to 4 carbon atoms), and the other is a hydrogen atom. It is preferable that one is a methyl group and the other is a hydrogen atom.

R ² in the general formula (4) 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. Examples of the oxyalkylene group of the repeating unit represented by OR ² include an oxyethylene group, an oxypropylene group, and an oxybutylene group. The oxyalkylene groups in the same molecule may be the same, or two or more oxyalkylene groups may be included.

  Among the polyoxyalkylene glycols represented by the general formula (4), from the viewpoint of refrigerant compatibility and viscosity-temperature characteristics, a copolymer containing an oxyethylene group (EO) and an oxypropylene group (PO) is used. Preferably, in such a case, the ratio of the oxyethylene group to the total of the oxyethylene group and the oxypropylene group (EO / (PO + EO)) is 0.1 to 0.8 from the standpoint of baking load and viscosity-temperature characteristics. It is preferable that it exists in the range, and it is more preferable that it exists in the range of 0.3-0.6.

  In terms of hygroscopicity and thermal oxidation stability, the value of EO / (PO + EO) is preferably in the range of 0 to 0.5, more preferably in the range of 0 to 0.2, and 0 (that is, Most preferred is a propylene oxide homopolymer).

F in the said General formula (4) is an integer of 1-80, g is an integer of 1-8. For example, when R ⁷ is an alkyl group or an acyl group, g is 1. When R ⁷ is a residue of a compound having 2 to 8 hydroxyl groups, g is the number of hydroxyl groups that the compound has.

  In addition, the product of f and g (f × g) is not particularly limited, but in order to satisfy the required performance as the above-described lubricating oil for a refrigerator in a balanced manner, the average value of f × g is 6 to 80. It is preferable to do so.

Among the polyoxyalkylene glycols having the above configuration, the following general formula (5):
_{CH 3 O- (C 3 H 6} O) h -CH 3 (5)
(In the formula, h represents a number of 6 to 80)
And polyoxypropylene glycol dimethyl ether represented by the following general formula (6):
_{CH 3 O- (C 2 H 4} O) i - (C 3 H 6 O) j -CH 3 (6)
(In the formula, i and j are each 1 or more, and i and j represent a number of 6 to 80)
The polyoxyethylene polyoxypropylene glycol dimethyl ether represented by the formula is suitable from the viewpoint of economy and the above-mentioned effects, and the following general formula (7):
_{C 4 H 9 O- (C 3} H 6 O) k -H (7)
(In the formula, k represents a number of 6 to 80)
In addition, polyoxypropylene glycol monobutyl ether represented by the following general formula (8):
_{CH 3 O- (C 3 H 6} O) l -H (8)
(Wherein l represents a number from 6 to 80)
Polyoxypropylene glycol monomethyl ether represented by the following general formula (9):
_{CH 3 O- (C 2 H 4} O) m - (C 3 H 6 O) n -H (9)
(In the formula, m and n are each 1 or more, and the total of m and n represents 6 to 80)
Polyoxyethylene polyoxypropylene glycol monomethyl ether represented by the following general formula (10):
_{C 4 H 9 O- (C 2} H 4 O) m - (C 3 H 6 O) n -H (10)
(In the formula, m and n are each 1 or more, and the total of m and n represents 6 to 80)
Polyoxyethylene polyoxypropylene glycol monobutyl ether, the following general formula (11):
_{CH 3 COO- (C 3 H 6} O) l -COCH 3 (11)
(Wherein l represents a number from 6 to 80)
Is preferable in terms of economy and the like.

［式（１２）中、Ｒ^４〜Ｒ^７は同一でも異なっていてもよく、それぞれ水素原子、炭素数１〜１０の１価の炭化水素基又は下記一般式（１３）：

（式（１３）中、Ｒ^８及びＲ^９は同一でも異なっていてもよく、それぞれ水素原子、炭素数１〜１０の１価の炭化水素基又は炭素数２〜２０のアルコキシアルキル基を表し、Ｒ^１０は炭素数２〜５のアルキレン基、アルキル基を置換基として有する総炭素数２〜５の置換アルキレン基又はアルコキシアルキル基を置換基として有する総炭素数４〜１０の置換アルキレン基を表し、ｒは０〜２０の整数を表し、Ｒ^１３は炭素数１〜１０の１価の炭化水素基を表す）
で表される基を表し、Ｒ^８〜Ｒ^１１の少なくとも１つが一般式（１３）で表される基である］
で表される構成単位を少なくとも１個有するポリオキシアルキレングリコール誘導体を使用することができる。 In the present invention, the polyoxyalkylene glycol is represented by the general formula (12):

[In the formula (12), R ^{4 to} R ⁷ may be the same or different, and each represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or the following general formula (13):

(In formula (13), R ⁸ and R ⁹ may be the same or different and each represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms, R ¹⁰ represents an alkylene group having 2 to 5 carbon atoms, a substituted alkylene group having 2 to 5 carbon atoms having an alkyl group as a substituent, or a substituted alkylene group having 4 to 10 carbon atoms having an alkoxyalkyl group as a substituent. , R represents an integer of 0 to 20, and R ¹³ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms)
Wherein at least one of R ^{8 to} R ¹¹ is a group represented by the general formula (13)]
A polyoxyalkylene glycol derivative having at least one structural unit represented by can be used.

In the above formula (12), R ^{4 to} R ⁷ each represent a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a group represented by the above general formula (13). Specific examples of the monovalent hydrocarbon group include a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 10 carbon atoms, and carbon. Examples thereof include cycloalkyl groups or alkylcycloalkyl groups having 5 to 10 carbon atoms, aryl groups or alkylaryl groups having 6 to 10 carbon atoms, and arylalkyl groups having 7 to 10 carbon atoms. Among these monovalent hydrocarbon groups, a monovalent hydrocarbon group having 6 or less carbon atoms, particularly an alkyl group having 3 or less carbon atoms, specifically, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. preferable.

In the general formula (13), R ⁸ and R ⁹ each represent a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. An alkyl group having a number of 3 or less or an alkoxyalkyl group having a carbon number of 6 or less is preferred. Specific examples of the alkyl group having 3 or less carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. Specific examples of the alkoxyalkyl group having 2 to 6 carbon atoms include methoxymethyl group, ethoxymethyl group, n-propoxymethyl group, isopropoxymethyl group, n-butoxymethyl group, isobutoxymethyl group, sec -Butoxymethyl group, tert-butoxymethyl group, pentoxymethyl group (including all isomers), methoxyethyl group (including all isomers), ethoxyethyl group (including all isomers), propoxyethyl Groups (including all isomers), butoxyethyl groups (including all isomers), methoxypropyl groups (including all isomers), ethoxypropyl groups (including all isomers), propoxypropyl groups ( All isomers included), methoxybutyl group (including all isomers), ethoxybutyl group (all isomers) Including), etc. methoxybutyl group (including all isomers).

In the general formula (13), R ¹⁰ is an alkylene group having 2 to 5 carbon atoms, a substituted alkylene group having 2 to 5 carbon atoms having an alkyl group as a substituent, or a total carbon number 4 having an alkoxyalkyl group as a substituent. Represents a substituted alkylene group having 10 to 10 carbon atoms, preferably an alkylene group having 2 to 4 carbon atoms and a substituted ethylene group having 6 or less carbon atoms in total. Specific examples of the alkylene group having 2 to 4 carbon atoms include an ethylene group, a propylene group, and a butylene group. Specific examples of the substituted ethylene group having 6 or less total carbon atoms include 1- (methoxymethyl) ethylene group, 2- (methoxymethyl) ethylene group, 1- (methoxyethyl) ethylene group, and 2- (methoxyethyl). ) Ethylene group, 1- (ethoxymethyl) ethylene group, 2- (ethoxymethyl) ethylene group, 1-methoxymethyl-2-methylethylene group, 1,1-bis (methoxymethyl) ethylene group, 2,2-bis (Methoxymethyl) ethylene group, 1,2-bis (methoxymethyl) ethylene group, 1-methyl-2-methoxymethylethylene group, 1-methoxymethyl-2-methylethylene group, 1-ethyl-2-methoxymethylethylene Group, 1-methoxymethyl-2-ethylethylene group, 1-methyl-2-ethoxymethylethylene group, 1-ethoxymethyl-2-methyl Ethylene, 1-methyl-2-methoxyethyl ethylene group, 1-methoxyethyl-2-methylethylene group, and the like.

In the general formula (13), R ¹¹ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms. Specifically, the hydrocarbon group may be a straight chain having 1 to 10 carbon atoms or A branched alkyl group, a linear or branched alkenyl group having 2 to 10 carbon atoms, a cycloalkyl group or alkylcycloalkyl group having 5 to 10 carbon atoms, an aryl group or alkylaryl having 6 to 10 carbon atoms Group, an arylalkyl group having 7 to 10 carbon atoms, and the like. Among these, a monovalent hydrocarbon group having 6 or less carbon atoms is preferable, and an alkyl group having 3 or less carbon atoms, specifically, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group is preferable.

In the general formula (12), at least one of R ^{4 to} R ⁷ is a group represented by the general formula (13). In particular, any one of R ^{4 and} R ⁶ is a group represented by the above general formula (13), and the other one of R ⁴ or R ⁶ and R ⁵ and R ⁷ are each a hydrogen atom or carbon. A monovalent hydrocarbon group having 1 to 10 is preferable.

［式（１４）中、Ｒ^１２〜Ｒ^１５は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１〜３のアルキル基を示す］
で表される構成単位からなる共重合体の三種類に大別することができる。上記単独重合体の好適例は、一般式（１２）で表される構成単位Ａを１〜２００個有するとともに、末端基がそれぞれ水酸基、炭素数１〜１０のアシルオキシ基、炭素数１〜１０のアルコキシ基あるいはアリーロキシ基からなるものを挙げることができる。一方、共重合体の好適例は、一般式（１２）で表される二種類の構成単位Ａ、Ｂをそれぞれ１〜２００個有するか、あるいは一般式（１２）で表される構成単位Ａを１〜２００個と一般式（１２）で表される構成単位Ｃを１〜２００個有するとともに、末端基がそれぞれ水酸基、炭素数１〜１０のアシルオキシ基、炭素数１〜１０のアルコキシ基あるいはアリーロキシ基からなるものを挙げることができる。これらの共重合体は、構成単位Ａと構成単位Ｂ(あるいは構成単位Ｃ)との交互共重合、ランダム共重合、ブロック共重合体あるいは構成単位Ａの主鎖に構成単位Ｂがグラフト結合したグラフト共重合体のいずれの重合形式であってもよい。 The polyoxyalkylene glycol having a structural unit represented by the general formula (12), preferably used in the present invention, is a homopolymer consisting only of the structural unit represented by the general formula (12); And a copolymer composed of two or more structural units having different structures, and a structural unit represented by the general formula (12) and other structural units, for example, the following general formula (14):

[In the formula (14), R ^{12 to} R ¹⁵ may be the same or different and each represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.]
Can be roughly divided into three types of copolymers consisting of structural units represented by: The preferred examples of the homopolymer have 1 to 200 structural units A represented by the general formula (12), and the terminal groups each have a hydroxyl group, an acyloxy group having 1 to 10 carbon atoms, and an alkyl group having 1 to 10 carbon atoms. The thing which consists of an alkoxy group or an aryloxy group can be mentioned. On the other hand, suitable examples of the copolymer have 1 to 200 of the two types of structural units A and B represented by the general formula (12), or the structural unit A represented by the general formula (12). 1 to 200 and 1 to 200 structural units C represented by the general formula (12), and each terminal group is a hydroxyl group, an acyloxy group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or aryloxy The thing which consists of groups can be mentioned. These copolymers include alternating copolymerization of the structural unit A and the structural unit B (or the structural unit C), a random copolymer, a block copolymer, or a graft in which the structural unit B is graft-bonded to the main chain of the structural unit A. Any polymerization form of the copolymer may be used.

［式（１５）中、Ｒ^１６〜Ｒ^１８は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の炭化水素基を表し、Ｒ^１９は炭素数１〜１０の２価の炭化水素基又は炭素数２〜２０の２価のエーテル結合酸素含有炭化水素基を表し、Ｒ^２０は炭素数１〜２０の炭化水素基を表し、ｓはその平均値が０〜１０の数を表し、Ｒ^１６〜Ｒ^２０は構成単位毎に同一であってもそれぞれ異なっていてもよく、また一般式（１５）で表される構成単位が複数のＲ^１９Ｏを有するとき、複数のＲ^１９Ｏは同一でも異なっていてもよい］
で表される構成単位を有するポリビニルエーテル系化合物が挙げられる。 Examples of the polyvinyl ether used in the present invention include the following general formula (15):

[In the formula (15), R ^{16 to} R ¹⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and R ¹⁹ is a divalent carbon atom having 1 to 10 carbon atoms. Represents a hydrogen group or a divalent ether-bonded oxygen-containing hydrocarbon group having 2 to ²⁰ carbon atoms, R ²⁰ represents a hydrocarbon group having 1 to ²⁰ carbon atoms, and s represents a number having an average value of 0 to 10. , R ^{16 to} R ²⁰ may be the same or different for each structural unit, and when the structural unit represented by the general formula (15) has a plurality of R ¹⁹ O, a plurality of R ¹⁹ Os. May be the same or different.]
The polyvinyl ether type compound which has a structural unit represented by these is mentioned.

［式（１６）中、Ｒ^２１〜Ｒ^２４は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の炭化水素基を表し、Ｒ^２１〜Ｒ^２４は構成単位毎に同一でも異なっていてもよい］
で表される構成単位とを有するブロック共重合体又はランダム共重合体からなるポリビニルエーテル系化合物も使用することができる。 Moreover, the structural unit represented by the above general formula (15) and the following general formula (16):

[In Formula (16), R ^{21 to} R ²⁴ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and R ^{21 to} R ²⁴ are the same or different for each constituent unit. It may be]
A polyvinyl ether compound comprising a block copolymer or a random copolymer having a structural unit represented by

R ^{16 to} R ¹⁸ in the general formula (15) each represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms (preferably 1 to 4 hydrocarbon group), and they may be the same or different from each other. Good. Specific examples of the hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, various pentyl groups, and various hexyl groups. Group, various heptyl groups, various octyl groups and other alkyl groups; cyclopentyl group, cyclohexyl group, various methylcyclohexyl groups, various ethylcyclohexyl groups, various dimethylcyclohexyl groups and other cycloalkyl groups, phenyl groups, various methylphenyl groups, various ethyl groups An aryl group such as a phenyl group and various dimethylphenyl groups; an arylalkyl group such as a benzyl group, various phenylethyl groups, and various methylbenzyl groups, and the like can be mentioned, and R ^{22 to} R ²⁴ are preferably an elementary atom.

On the other hand, R ¹⁹ in the general formula (15) is a divalent hydrocarbon group having 1 to 10 carbon atoms (preferably 2 to 10) or a divalent ether bond oxygen-containing hydrocarbon group having 2 to 20 carbon atoms. Represents. Specific examples of the divalent hydrocarbon group having 1 to 10 carbon atoms include methylene group, ethylene group, phenylethylene group, 1,2-propylene group, 2-phenyl-1,2-propylene group, 1, Divalent aliphatic chain hydrocarbon groups such as 3-propylene group, various butylene groups, various pentylene groups, various hexylene groups, various heptylene groups, various octylene groups, various nonylene groups, and various decylene groups; cyclohexane, methylcyclohexane, Cycloaliphatic hydrocarbon groups having two bonding sites on cycloaliphatic hydrocarbons such as ethylcyclohexane, dimethylcyclohexane, propylcyclohexane; various phenylene groups, various methylphenylene groups, various ethylphenylene groups, various dimethylphenylene groups, various Divalent aromatic hydrocarbon groups such as naphthylene groups; toluene, xylene, ethylbenzene, etc. An alkyl aromatic hydrocarbon group having a monovalent bonding site on each of the alkyl group part and the aromatic part of the alkyl aromatic hydrocarbon; an alkyl having a binding site on the alkyl group part of a polyalkyl aromatic hydrocarbon such as xylene or diethylbenzene An aromatic hydrocarbon group, and the like. Among these, an aliphatic chain hydrocarbon group having 2 to 4 carbon atoms is particularly preferable.

Specific examples of the divalent ether bond oxygen-containing hydrocarbon group having 2 to 20 carbon atoms include methoxymethylene group, methoxyethylene group, methoxymethylethylene group, 1,1-bismethoxymethylethylene group, 1,2 Preferred examples include -bismethoxymethylethylene group, ethoxymethylethylene group, (2-methoxyethoxy) methylethylene group, (1-methyl-2-methoxy) methylethylene group, and the like. Incidentally, s in the general formula (15) represents a repeating number of ^{R 19} O, the average value thereof is 0 to 10, preferably a number in the range of 0-5. When the R ^{19 O} is more, the same configuration units, a plurality of R ^{19 O} may be the same or different.

Furthermore, R ²⁰ in the general formula (15) represents a hydrocarbon group having 1 to ²⁰ carbon atoms, preferably 1 to 10 carbon atoms. Specific examples of the hydrocarbon group include a methyl group, an ethyl group, and n. -Propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, various decyl groups, etc. Alkyl group: Cyclopentyl group, cyclohexyl group, various methylcyclohexyl groups, various ethylcyclohexyl groups, various propylcyclohexyl groups, various dimethylcyclohexyl groups and other cycloalkyl groups; phenyl group, various methylphenyl groups, various ethylphenyl groups, various dimethylphenyls Groups, various propylphenyl groups, various trimethylphenyl groups, various types Examples include aryl groups such as butylphenyl group and various naphthyl groups; arylalkyl groups such as benzyl group, various phenylethyl groups, various methylbenzyl groups, various phenylpropyl groups, and various phenylbutyl groups. R ^{22 to} R ²⁶ may be the same or different for each structural unit.

  When the polyvinyl ether according to the present invention is a homopolymer consisting only of the structural unit represented by the general formula (15), the carbon / oxygen molar ratio is preferably in the range of 4.2 to 7.0. . If the molar ratio is less than 4.2, the hygroscopicity becomes excessively high, and if it exceeds 7.0, the compatibility with the refrigerant tends to be reduced.

In the general formula (16), R ^{21 to} R ²⁴ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. Examples of the hydrocarbon group having 1 to 20 carbon atoms, and hydrocarbon groups exemplified in the description of R ²⁰ in the general formula (15). R ^{21 to} R ²⁴ may be the same or different for each structural unit.

  When the polyvinyl ether according to the present invention is a block copolymer or a random copolymer having a structural unit represented by the general formula (15) and a structural unit represented by the general formula (16), the carbon / oxygen The molar ratio is preferably in the range of 4.2 to 7.0. If the molar ratio is less than 4.2, the hygroscopicity becomes excessively high, and if it exceeds 7.0, the compatibility with the refrigerant tends to be reduced.

  Furthermore, in this invention, the homopolymer which consists only of the structural unit represented by the said General formula (15), the structural unit represented by the said General formula (15), and the structure represented by the said General formula (16) Mixtures of block copolymers or random copolymers composed of units can also be used. These homopolymers and copolymers can be produced by polymerization of corresponding vinyl ether monomers and copolymerization of corresponding hydrocarbon monomers having olefinic double bonds and corresponding vinyl ether monomers.

［式（１７）中、Ｒ^２５〜Ｒ^２７は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の炭化水素基を表し、Ｒ^２８は炭素数１〜１０の２価の炭化水素基又は炭素数２〜２０の２価のエーテル結合酸素含有炭化水素基を表し、Ｒ^２９は炭素数１〜２０の炭化水素基を表し、ｔはその平均値が０〜１０の数を表し、上記一般式（１７）で表される末端構造が複数のＲ^２８Ｏを有するとき、複数のＲ^２８Ｏはそれぞれ同一でも異なっていてもよい］

［式（１８）中、Ｒ^３０〜Ｒ^３１は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］
で表されるものであり、且つ他方が下記一般式（１９）又は（２０）：

［式（１９）中、Ｒ^３４〜Ｒ^３６は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の炭化水素基を表し、Ｒ^３７は炭素数１〜１０の２価の炭化水素基又は炭素数２〜２０の２価のエーテル結合酸素含有炭化水素基を表し、Ｒ^３８は炭素数１〜２０の炭化水素基を表し、ｔはその平均値が０〜１０の数を表し、上記一般式（１９）で表される末端構造が複数のＲ^３７Ｏを有するとき、複数のＲ^３７Ｏはそれぞれ同一でも異なっていてもよい］

［式（２０）中、Ｒ^３９〜Ｒ^４２は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］
で表される構造を有するもの；及び
その末端の一方が、上記一般式（１７）又は（１８）で表され、且つ他方が下記一般式（２１）：

［式（２１）中、Ｒ^４３〜Ｒ^４５は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の炭化水素基を表す］
で表される構造を有するものが好ましい。このようなポリビニルエーテルの中でも、次に挙げるものが特に好適である。 As the polyvinyl ether used in the present invention, one of the terminal structures has the following general formula (17) or (18):

[In Formula (17), R ^{25 to} R ²⁷ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms; R ²⁸ is a divalent carbon atom having 1 to 10 carbon atoms; Represents a hydrogen group or a divalent ether-bonded oxygen-containing hydrocarbon group having 2 to 20 carbon atoms, R ²⁹ represents a hydrocarbon group having 1 to 20 carbon atoms, and t represents a number having an average value of 0 to 10. When the terminal structure represented by the general formula (17) has a plurality of R ²⁸ Os, the plurality of R ²⁸ Os may be the same or different.

[In the formula (18), R ^{30 to} R ³¹ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms]
And the other is represented by the following general formula (19) or (20):

[In the formula (19), R ^{34 to} R ³⁶ may be the same or different, and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and R ³⁷ is a divalent carbon atom having 1 to 10 carbon atoms. Represents a hydrogen group or a divalent ether-bonded oxygen-containing hydrocarbon group having 2 to 20 carbon atoms, R ³⁸ represents a hydrocarbon group having 1 to 20 carbon atoms, and t represents a number having an average value of 0 to 10. When the terminal structure represented by the general formula (19) has a plurality of R ³⁷ O, the plurality of R ³⁷ O may be the same or different from each other]

[In Formula (20), R ^{39 to} R ⁴² may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms]
One of its ends is represented by the above general formula (17) or (18), and the other is represented by the following general formula (21):

[In formula (21), R ^{43 to} R ⁴⁵ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms]
What has the structure represented by these is preferable. Among such polyvinyl ethers, the following are particularly suitable.

(1) One of the terminals has a structure represented by General Formula (17) or (18) and the other is represented by General Formula (19) or (20), and R ¹⁶ in General Formula (15) -R ¹⁸ are all hydrogen atoms, s is a number from 0 to 4, R ¹⁹ is a divalent hydrocarbon group having 2 to 4 carbon atoms, and R ²⁰ is a carbon atom having 1 to ²⁰ carbon atoms. Being a hydrogen group;
(2) It has only the structural unit represented by the general formula (15), and one end of the structural unit is represented by the general formula (17) and the other has a structure represented by the general formula (18). R ^{16 to} R ¹⁸ in the general formula (15) are all hydrogen atoms, s is a number from 0 to 4, and R ¹⁹ is a divalent hydrocarbon group having 2 to 4 carbon atoms. And R ²⁰ is a hydrocarbon group having 1 to ²⁰ carbon atoms;
(3) One of the terminals has a structure represented by the general formula (17) or (18) and the other is represented by the general formula (19), and R ^{16 to} R ¹⁸ in the general formula (15) are All are hydrogen atoms, s is a number from 0 to 4, R ¹⁹ is a divalent hydrocarbon group having 2 to 4 carbon atoms, and R ²⁰ is a hydrocarbon group having 1 to ²⁰ carbon atoms. thing;
(4) It has only the structural unit represented by the general formula (15), and one end thereof is represented by the general formula (17) and the other has a structure represented by the general formula (20). R ^{16 to} R ¹⁸ in the general formula (15) are all hydrogen atoms, s is a number from 0 to 4, and R ¹⁹ is a divalent hydrocarbon group having 2 to 4 carbon atoms. R ²⁰ is a hydrocarbon group having 1 to ²⁰ carbon atoms.

［式（２２）中、Ｒ^４６〜Ｒ^４８は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の炭化水素基を表し、Ｒ^４９及びＲ^５１は同一でも異なっていてもよく、それぞれ炭素数２〜１０の２価の炭化水素基を表し、Ｒ^５０及びＲ^５２は同一でも異なっていてもよく、それぞれ炭素数１〜１０の炭化水素基を表し、ｕ及びｖは同一でも異なっていてもよく、それぞれその平均値が０〜１０の数を表し、上記一般式（２２）で表される末端構造が複数のＲ^４９Ｏ又はＲ^５１Ｏを有するとき、複数のＲ^４９Ｏ又はＲ^５１Ｏは同一であっても異なっていてもよい］
で表される構造を有するポリビニルエーテル系化合物も使用することができる。 Moreover, in this invention, it has a structural unit represented by the said General formula (15), One of the terminal is represented by General formula (17), and the other is following General formula (22):

[In the formula (22), R ^{46 to} R ⁴⁸ may be the same or different, each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and R ⁴⁹ and R ⁵¹ may be the same or different. Each represents a divalent hydrocarbon group having 2 to 10 carbon atoms, R ⁵⁰ and R ⁵² may be the same or different, each represents a hydrocarbon group having 1 to 10 carbon atoms, and u and v may be the same. When the terminal structure represented by the general formula (22) has a plurality of R ⁴⁹ O or R ⁵¹ O, the average value thereof may be different, and each of the average values represents a number of R ⁴⁹ O. Or R ⁵¹ O may be the same or different.]
A polyvinyl ether compound having a structure represented by the formula can also be used.

［式（２３）中、Ｒ^５３は炭素数１〜８の炭化水素基を示す］

［式（２４）中、Ｒ^５４は炭素数１〜８の炭化水素基を示す］
で表される構成単位からなり、かつ重量平均分子量が３００〜５,０００であって、末端の一方が下記一般式（２５）又は（２６）：

［式（２５）中、Ｒ^５５は炭素数１〜３のアルキル基を表し、Ｒ^５６は炭素数１〜８の炭化水素基を示す］

［式（２６）中、Ｒ^５７は炭素数１〜８の炭化水素基を示す］
で表される構造を有するアルキルビニルエーテルの単独重合物又は共重合物からなるポリビニルエーテル系化合物も使用することができる。 Furthermore, in the present invention, the following general formula (23) or (24):

[In formula (23), R ⁵³ represents a hydrocarbon group having 1 to 8 carbon atoms]

[In the formula (24), R ⁵⁴ represents a hydrocarbon group having 1 to 8 carbon atoms]
And the weight average molecular weight is 300 to 5,000, and one of the terminals is represented by the following general formula (25) or (26):

[In the formula (25), R ⁵⁵ represents an alkyl group having 1 to 3 carbon atoms, and R ⁵⁶ represents a hydrocarbon group having 1 to 8 carbon atoms]

[In formula (26), R ⁵⁷ represents a hydrocarbon group having 1 to 8 carbon atoms]
A polyvinyl ether compound comprising a homopolymer or copolymer of an alkyl vinyl ether having a structure represented by

  In the present invention, only one kind selected from the group consisting of the mineral oil and the synthetic oil described above may be used alone, or two or more kinds may be used in combination. When the refrigerating machine oil composition of the present invention is used in an open type compressor such as a car air conditioner using an HFC refrigerant, among the above-described mineral oil and synthetic oil, polyoxyalkylene glycol, ester, and polyvinyl ether are preferable. . Moreover, when using the refrigerator oil composition of this invention for closed compressors, such as a refrigerator and an air conditioning apparatus, alkylbenzene, ester, and polyvinyl ether are preferable.

  The refrigerating machine oil composition of the present invention contains an ester of a carboxylic acid containing hydroxycarboxylic acid and an alcohol (hereinafter referred to as “ester compound (A)” for convenience).

  Here, the “hydroxycarboxylic acid” (also referred to as “hydroxyacid”) in the present invention means a carboxylic acid further having a hydroxyl group in addition to the hydroxyl group contained in the carboxylic acid group (—COOH). The number of carbon atoms of the hydroxycarboxylic acid is arbitrary, and usually a hydroxycarboxylic acid having 2 to 40 carbon atoms is used, but the number of carbon atoms of the hydroxycarboxylic acid is 6 or more from the viewpoint of reducing the friction coefficient and stability. It is preferably 8 or more, more preferably 10 or more. Moreover, from the viewpoint of precipitation prevention at low temperatures and solubility in a lubricating base oil, the number of carbon atoms of the hydroxycarboxylic acid is preferably 30 or less, and more preferably 24 or less.

  The hydroxycarboxylic acid may be a saturated carboxylic acid or an unsaturated carboxylic acid, but is preferably a saturated carboxylic acid from the viewpoint of stability. Further, the hydroxycarboxylic acid may be a linear carboxylic acid or a branched carboxylic acid, but the linear carboxylic acid or 1 to 2 branched chains having 1 or 2 carbon atoms (more preferably 1 carbon atoms) ( More preferably, it is a branched carboxylic acid having 1 to 2, particularly preferably 1).

  Further, the number of carboxylic acid groups that the hydroxycarboxylic acid has is not particularly limited, and may be either the hydroxycarboxylic acid monobasic acid or the polybasic acid, but is preferably a monobasic acid.

  In addition, the number of hydroxyl groups that the hydroxycarboxylic acid has is not particularly limited, but is preferably 1 to 4, more preferably 1 to 3, more preferably 1 to 2 from the viewpoint of stability. Is more preferable and one is particularly preferable.

  In addition, the bonding position of the hydroxyl group in the hydroxycarboxylic acid is arbitrary, but the main chain as viewed from the bonding carbon atom of the carboxylic acid group (α-hydroxycarboxylic acid) or the carboxylic acid group bonding carbon atom of the carboxylic acid group. A carboxylic acid having a hydroxyl group bonded to the carbon atom at the other end (ω-hydroxycarboxylic acid) is preferred.

［式中、Ｒ^５８は水素原子、炭素数１〜３８のアルキル基又は炭素数２〜３８のアルケニル基を示す。］

［式中、Ｒ^５９は水素原子、炭素数１〜３８のアルキレン基又は炭素数２〜３８のアルケニレン基を示す。］ Specific preferred examples of the hydroxycarboxylic acid include α-hydroxycarboxylic acid represented by the following general formula (A-1) and ω-hydroxycarboxylic acid represented by the following general formula (A-2). It is done.

[Wherein, R ⁵⁸ represents a hydrogen atom, an alkyl group having 1 to 38 carbon atoms, or an alkenyl group having 2 to 38 carbon atoms. ]

[Wherein, R ⁵⁹ represents a hydrogen atom, an alkylene group having 1 to 38 carbon atoms, or an alkenylene group having 2 to 38 carbon atoms. ]

In the above general formula (A-1), R ⁵⁸ represents a hydrogen atom, an alkyl group having 1 to 38 carbon atoms, or an alkenyl group having 2 to 38 carbon atoms. The alkyl and alkenyl groups represented by R ^58, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, 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, nonadecyl group, icosyl group, heicosyl group, docosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl Group, nonacosyl group, triacontyl group, hentriacontyl group, dotriacontyl group, tritriacontyl group, tetratriacontyl group, pentatriacontyl group, hexatriacontyl group, heptatriacontyl group, octatriacontyl group Archi Group (including all isomers); ethenyl group (vinyl group), propenyl group (allyl group), butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group Group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, nonadecenyl group, icocenyl group, henicocenyl group, dococenyl group, tricosenyl group, tetracocenyl group, pentacocenyl group, hexacocenyl group, heptacocenyl group, heptacocenyl group Nonacosenyl group, triacontenyl group, hentriacontenyl group, dotriacontenyl group, tritriacontenyl group, tetratriacontenyl group, pentatriacontenyl group, hexatriacontenyl group, heptato Akonteniru group, (including all isomers) alkenyl groups such as octa thoria Conte sulfonyl group and the like.

In General Formula (A-2), R ⁵⁹ represents a hydrogen atom, an alkylene group having 1 to 38 carbon atoms, or an alkenylene group having 2 to 38 carbon atoms. As the alkylene group and alkenylene group represented by R ^59, specifically, methylene group, ethylene group, propylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene , Dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group, octadecylene group, nonadecylene group, icosylene group, heicosylene group, docosylene group, tricosylene group, tetracosylene group, pentacosylene group, hexacosylene group, heptacene group Group, octacosylene group, nonacosylene group, triacontylene group, hentriacontylene group, dotriacontylene group, tritriacontylene group, tetratriacontylene group, pentatriacontylene group, hexa Alkylene groups (including all isomers) such as triacontylene group, heptatriacontylene group and octatriacontylene group; ethenylene group (vinylene group), propenyl group (arylene group), butenylene group, pentenylene group, hexenylene group Group, heptenylene group, octenylene group, nonenylene group, decenylene group, undecenylene group, dodecenylene group, tridecenylene group, tetradecenylene group, pentadecenylene group, hexadecenylene group, heptadecylene group, octadecenylene group, nonodecenylene group, icodecenylene group, icodenylene group, icodenylene group, Tricosenylene group, Tetracosenylene group, Pentacosenylene group, Hexacosenylene group, Heptacosenylene group, Octacosenylene group, Nonacosenylene group, Triacontenylene group, Hentriacon Alkenylene groups such as Nylene, Dotria Contenylene, Tritria Contenylene, Tetratria Contenylene, Pentatria Contenylene, Hexatria Contenylene, Heptatria Contenylene, Octatria Contenylene, etc. (all Isomers) and the like.

  As a raw material containing such a hydroxycarboxylic acid, a lanolin fatty acid obtained by purifying (hydrolyzing etc.) a waxy substance adhering to sheep wool can be preferably used.

  The constituent carboxylic acid of the ester compound (A) may be composed only of hydroxycarboxylic acid, but may further contain a carboxylic acid having no hydroxyl group. The “carboxylic acid having no hydroxyl group” herein means a carboxylic acid having no hydroxyl group in addition to the hydroxyl group contained in the carboxylic acid group (—COOH).

  When the constituent carboxylic acid of the ester (A) contains both a hydroxycarboxylic acid and a carboxylic acid having no hydroxyl group, the content of the hydroxycarboxylic acid is preferably 3% by mass or more based on the total amount of the constituent carboxylic acid. , More preferably 5% by mass or more, further preferably 10% by mass or more, particularly preferably 20% by mass or more, preferably 80% by mass or less, more preferably 60% by mass or less, still more preferably 50% by mass. Hereinafter, it is particularly preferably 40% by mass or less. When the content of hydroxycarboxylic acid is less than the lower limit, the friction reducing effect tends to be insufficient. On the other hand, when the content of the hydroxycarboxylic acid exceeds the upper limit, the solubility in the lubricating base oil tends to be insufficient.

  The carboxylic acid having no hydroxyl group may be a saturated carboxylic acid or an unsaturated carboxylic acid, but a saturated carboxylic acid is preferable from the viewpoint of stability.

  The carboxylic acid having no hydroxyl group may be a linear carboxylic acid or a branched carboxylic acid, but may be a linear carboxylic acid or a branched group having 1 to 2 carbon atoms (more preferably 1 carbon atom). A branched carboxylic acid having 1 to 3 (more preferably 1 to 2, particularly preferably 1) is preferable. Moreover, about the branch of branched carboxylic acid, a methyl branch or an ethyl branch is preferable, and a methyl branch is especially preferable.

  Carbon number of the carboxylic acid having no hydroxyl group is arbitrary, and carboxylic acid having 2 to 40 carbon atoms is usually used. From the viewpoint of reducing the friction coefficient, the carbon number of the carboxylic acid is 8 or more. Is more preferable and 10 or more is more preferable. Further, from the viewpoint of solubility in a lubricating base oil and prevention of precipitation at low temperatures, the carbon number of the carboxylic acid is preferably 30 or less, and more preferably 24 or less.

  The number of carboxylic acid groups in the saturated carboxylic acid having no hydroxyl group is not particularly limited and may be either a monobasic acid or a polybasic acid, but is preferably a monobasic acid.

  Specific examples of the carboxylic acid having no hydroxyl group include linear or branched hexanoic acid, linear or branched heptanoic acid, linear or branched octanoic acid, linear or branched Nonanoic acid, linear or branched decanoic acid, linear or branched undecanoic acid, linear or branched dodecanoic acid, linear or branched tridecanoic acid, linear or branched Tetradecanoic acid, linear or branched pentadecanoic acid, linear or branched hexadecanoic acid, linear or branched heptadecanoic acid, linear or branched octadecanoic acid, linear or branched Nonadecanoic acid, linear or branched icosanoic acid, linear or branched heicosanoic acid, linear or branched docosanoic acid, linear or branched tricosanoic acid, linear or branched Tetracosanoic acid, linear or branched Pentacosanoic acid, linear or branched hexacosanoic acid, linear or branched heptacosanoic acid, linear or branched octacosanoic acid, linear or branched nonacosanoic acid, linear or branched Saturated fatty acids such as triacontanoic acid; linear or branched hexenoic acid, linear or branched heptenoic acid, linear or branched octenoic acid, linear or branched nonenoic acid, linear Linear or branched decenoic acid, linear or branched undecenoic acid, linear or branched dodecenoic acid, linear or branched tridecenoic acid, linear or branched tetradecenoic acid, linear Linear or branched pentadecenoic acid, linear or branched hexadecenoic acid, linear or branched heptadecenoic acid, linear or branched octadecenoic acid, linear or branched nonadecenoic acid, linear Or branched icon Acid, linear or branched henicosenic acid, linear or branched docosenoic acid, linear or branched tricosenoic acid, tetracosenoic acid, linear or branched pentacosenoic acid, linear or Unsaturation such as branched hexacosenoic acid, linear or branched heptacenoic acid, linear or branched octacosenoic acid, linear or branched nonacosenic acid, linear or branched triacontenoic acid, etc. Examples include fatty acids and mixtures of two or more thereof.

  When the constituent carboxylic acid of the ester compound (A) contains both a hydroxycarboxylic acid and a carboxylic acid having no hydroxyl group, the content of the carboxylic acid having no hydroxyl group is preferably based on the total amount of the constituent carboxylic acid. Is 97% by mass or less, more preferably 95% by mass or less, further preferably 90% by mass or less, particularly preferably 80% by mass or less, preferably 20% by mass or more, more preferably 40% by mass or more, Preferably it is 50 mass% or more, Most preferably, it is 60 mass% or more. When the content of carboxylic acid having no hydroxyl group exceeds the upper limit, the friction reducing effect tends to be insufficient. On the other hand, when the content of the carboxylic acid having no hydroxyl group is less than the lower limit, the solubility in the lubricating base oil tends to be insufficient.

  In the ester compound (A), the proportion of carboxylic acids having 24 or less carbon atoms in the constituent carboxylic acid (total of hydroxycarboxylic acids and carboxylic acids having no hydroxyl group) is 75 on the basis of the total amount of the constituent carboxylic acids. Is preferably 100 to 100% by mass, more preferably 80 to 100% by mass, still more preferably 85 to 100% by mass, still more preferably 90 to 100% by mass, and 92 to 100% by mass. % Is particularly preferred. When the proportion of the carboxylic acid having 24 or less carbon atoms is less than the lower limit, the friction reducing effect, the solubility in the lubricating base oil, and the precipitation preventing property at low temperatures tend to be insufficient. For the same reason, in the ester compound (A), the proportion of carboxylic acid having 25 or more carbon atoms in the constituent carboxylic acid (total of hydroxycarboxylic acid and carboxylic acid having no hydroxyl group) is the total amount of constituent carboxylic acid. Is preferably 0 to 25% by mass, more preferably 0 to 20% by mass, still more preferably 0 to 15% by mass, and still more preferably 0 to 10% by mass. 0 to 8% by mass is particularly preferable.

  The alcohol constituting the ester compound (A) may be a monohydric alcohol or a polyhydric alcohol.

  The monohydric alcohol may be a linear alcohol or a branched alcohol, and may be either a saturated alcohol or an unsaturated alcohol. Moreover, although carbon number of monohydric alcohol is arbitrary, it is 1-36 normally, Preferably it is 1-24.

  Specific examples of the monohydric alcohol include methanol, ethanol, linear or branched propanol, linear or branched butanol, linear or branched pentanol, linear or branched, and the like. Hexanol, linear or branched heptanol, linear or branched octanol, linear or branched nonanol, linear or branched decanol, linear or branched undecanol, linear Linear or branched dodecanol, linear or branched tridecanol, linear or branched tetradecanol, linear or branched pentadecanol, linear or branched hexadecanol, straight Linear or branched heptadecanol, linear or branched octadecanol, linear or branched nonadecanol, linear or branched icosanol, linear Or branched Hen'ikosanoru, linear or branched Torikosanoru, such as linear or branched tetracosanol, and mixtures thereof. Among these, a monohydric alcohol having 1 to 18 carbon atoms is preferable and a monohydric alcohol having 1 to 12 carbon atoms is more preferable from the viewpoint of solubility in a lubricating base oil.

  It is preferable to use a monohydric alcohol as a constituent alcohol of the ester compound (A) because solubility in a lubricating base oil and prevention of precipitation at low temperature are further improved. As a particularly preferred embodiment, for example, a refrigerating machine oil composition in which the lubricating base oil is a polyhydric alcohol ester and the ester compound (A) is an ester of a monohydric alcohol. In this case, the polyhydric alcohol ester which is the lubricating base oil may be either a complete ester or a partial ester, but is preferably a complete ester.

  Moreover, as a polyhydric alcohol used for ester compound (A), 2-10 valent alcohol is used normally, Preferably it is 2-6 valent alcohol. Specific examples of such polyhydric alcohols include ethylene glycol, diethylene glycol, polyethylene glycol (3 to 15 mer of ethylene glycol), propylene glycol, dipropylene glycol, and polypropylene glycol (3 to 15 amount of propylene glycol). Body), 1,3-propanediol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,2-propanediol, 2-methyl-1,3- Dihydric alcohols such as propanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, neopentylglycol; glycerin, polyglycerin (2-8 of glycerin) Such as diglycerin, triglycer Phosphorus, tetraglycerin, etc.), trimethylolalkanes (trimethylolethane, trimethylolpropane, trimethylolbutane, etc.) and their 2- to 8-mer, pentaerythritol and their 2- to 4-mer, 1,2,4- Butanetriol, 1,3,5-pentanetriol, 1,2,6-hexanetriol, 1,2,3,4-butanetetrol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, mannitol, etc. Polyhydric alcohols; sugars such as xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, and mixtures thereof That.

  Among these polyhydric alcohols, ethylene glycol, diethylene glycol, polyethylene glycol (ethylene glycol 3-10 mer), propylene glycol, dipropylene glycol, polypropylene glycol (propylene glycol 3-10 mer), 1,3- Propanediol, 2-methyl-1,2-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, glycerin, diglycerin, triglycerin, trimethylolalkane (trimethylolethane, trimethylolpropane, trimethylol Methylol butane and the like, and dimers and tetramers thereof, pentaerythritol, dipentaerythritol, 1,2,4-butanetriol, 1,3,5-pentanetriol, 1,2,6-hexanetriol , 1,2,3,4 butane tetrol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, divalent to hexavalent polyhydric alcohols and mixtures thereof, such as mannitol and the like are preferable. Furthermore, ethylene glycol, propylene glycol, neopentyl glycol, glycerin, trimethylol ethane, trimethylol propane, pentaerythritol, sorbitan, and a mixture thereof are more preferable because they are more excellent in preventing cylinder noise.

  It is preferable to use a polyhydric alcohol as the constituent alcohol of the ester compound (A) because the friction reducing effect is further improved. The ester compound (A) obtained using a polyhydric alcohol may be a complete ester in which all of the hydroxyl groups of the polyhydric alcohol are esterified, or some of the hydroxyl groups remain unreacted. It may be a partial ester. Furthermore, when the constituent carboxylic acid of the ester compound (A) is a polybasic acid, it may be a complete ester obtained by esterifying all of the carboxyl groups of the ester compound (A). It may be a partial ester remaining unreacted. From the point of friction reduction effect, it is preferable to use a partial ester in which a hydroxyl group or a carboxyl group remains unreacted. A particularly preferred embodiment includes a refrigerating machine oil composition in which the lubricating base oil is a complete ester and the ester compound (A) is a partial ester of a polyhydric alcohol ester.

  The preparation method of the ester compound (A) is arbitrary, but an ester obtained by reacting a fatty acid (lanolin fatty acid) obtained by saponifying and decomposing lanolin from sheep wool with an alcohol is particularly preferable.

  The content of the ester compound (A) in the refrigerating machine oil composition of the present invention is preferably 0.01% by mass or more, more preferably, based on the total amount of the composition, from the viewpoint that both the static friction coefficient and the dynamic friction coefficient can be further reduced. Is 0.1% by mass or more, more preferably 0.5% by mass or more. In addition, the content of the ester compound (A) is preferably 10% by mass or less, more preferably, based on the total amount of the composition from the viewpoint of suppressing a decrease in the stability of the refrigerating machine oil composition accompanying an increase in the content. It is 7 mass% or less, More preferably, it is 5 mass% or less.

  The refrigerating machine oil composition of the present invention may be composed of the above lubricating base oil and ester compound (A), but in order to further enhance its performance, the additives shown below are further added as necessary. Can be contained.

In the refrigerating machine oil composition of the present invention, it is preferable to blend (B) an epoxy compound in order to further improve its thermal / hydrolytic stability and frictional properties. (B) As a preferable example of an epoxy compound, the compound shown to the following (B1)-(B8) is mentioned.
(B1) phenyl glycidyl ether type epoxy compound (B2) alkyl glycidyl ether type epoxy compound (B3) glycidyl ester type epoxy compound (B4) allyl oxirane compound (B5) alkyl oxirane compound (B6) alicyclic epoxy compound (B7) epoxy Fatty acid monoester (B8) epoxidized vegetable oil.

  Specific examples of the (B1) phenyl glycidyl ether type epoxy compound include phenyl glycidyl ether and alkylphenyl glycidyl ether. As used herein, the alkylphenyl glycidyl ether includes those having 1 to 3 alkyl groups having 1 to 13 carbon atoms, and those having one alkyl group having 4 to 10 carbon atoms, such as n-butylphenyl glycidyl. Ether, i-butylphenyl glycidyl ether, sec-butylphenyl glycidyl ether, tert-butylphenyl glycidyl ether, pentylphenyl glycidyl ether, hexylphenyl glycidyl ether, heptylphenyl glycidyl ether, octylphenyl glycidyl ether, nonylphenyl glycidyl ether, decylphenyl A glycidyl ether etc. can be illustrated as a preferable thing.

  (B2) As the alkyl glycidyl ether type epoxy compound, specifically, decyl glycidyl ether, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, 2-ethylhexyl glycidyl ether, neopentyl glycol di Examples thereof include glycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1,6-hexanediol diglycidyl ether, sorbitol polyglycidyl ether, polyalkylene glycol monoglycidyl ether, polyalkylene glycol diglycidyl ether and the like.

  Specific examples of the (B3) glycidyl ester type epoxy compound include compounds represented by the following general formula (B-1).

［式中、Ｒ^６０は炭素数１〜１８の炭化水素基を表す］

[Wherein R ⁶⁰ represents a hydrocarbon group having 1 to 18 carbon atoms]

In the above formula (B-1), R ⁶⁰ represents a hydrocarbon group having 1 to 18 carbon atoms. Examples of such a hydrocarbon group include an alkyl group having 1 to 18 carbon atoms and an alkenyl group having 2 to 18 carbon atoms. Group, cycloalkyl group having 5 to 7 carbon atoms, alkyl cycloalkyl group having 6 to 18 carbon atoms, aryl group having 6 to 10 carbon atoms, alkylaryl group having 7 to 18 carbon atoms, arylalkyl having 7 to 18 carbon atoms Groups and the like. Among these, an alkylphenyl group having an alkyl group having 5 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, a phenyl group, and an alkyl group having 1 to 4 carbon atoms is preferable.

  (B3) Among the glycidyl ester type epoxy compounds, preferred examples include glycidyl-2,2-dimethyloctanoate, glycidyl benzoate, glycidyl-tert-butyl benzoate, glycidyl acrylate, glycidyl methacrylate and the like. It can be illustrated.

  Specific examples of the (B4) allyloxirane compound include 1,2-epoxystyrene, alkyl-1,2-epoxystyrene, and the like.

  Specific examples of the (B5) alkyloxirane compound include 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-epoxyheptane, 1,2-epoxyoctane, 1 , 2-epoxynonane, 1,2-epoxydecane, 1,2-epoxyundecane, 1,2-epoxydodecane, 1,2-epoxytridecane, 1,2-epoxytetradecane, 1,2-epoxypentadecane, 1, 2,2-epoxyhexadecane, 1,2-epoxyheptadecane, 1,1,2-epoxyoctadecane, 2-epoxynonadecane, 1,2-epoxyicosane and the like.

  (B6) As an alicyclic epoxy compound, the compound in which the carbon atom which comprises an epoxy group directly comprises the alicyclic ring like the compound represented by the following general formula (B-2) is mentioned. .

（Ｂ６）脂環式エポキシ化合物としては、具体的には、１，２−エポキシシクロヘキサン、１，２−エポキシシクロペンタン、３，４−エポキシシクロヘキシルメチル−３，４−エポキシシクロヘキサンカルボキシレート、ビス（３，４−エポキシシクロヘキシルメチル）アジペート、エキソ−２，３−エポキシノルボルナン、ビス（３，４−エポキシ−６−メチルシクロヘキシルメチル）アジペート、２−（７−オキサビシクロ［４．１．０］ヘプト−３−イル）−スピロ（１，３−ジオキサン−５，３‘−［７］オキサビシクロ［４．１．０］ヘプタン、４−（１‘−メチルエポキシエチル）−１，２−エポキシ−２−メチルシクロヘキサン、４−エポキシエチル−１，２−エポキシシクロヘキサン等が例示できる。

Specific examples of the (B6) alicyclic epoxy compound include 1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis ( 3,4-epoxycyclohexylmethyl) adipate, exo-2,3-epoxynorbornane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 2- (7-oxabicyclo [4.1.0] hept -3-yl) -spiro (1,3-dioxane-5,3 ′-[7] oxabicyclo [4.1.0] heptane, 4- (1′-methylepoxyethyl) -1,2-epoxy Examples thereof include 2-methylcyclohexane and 4-epoxyethyl-1,2-epoxycyclohexane.

  Specific examples of the (B7) epoxidized fatty acid monoester include esters of epoxidized fatty acids having 12 to 20 carbon atoms with alcohols or phenols having 1 to 8 carbon atoms and alkylphenols. In particular, butyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl, phenyl and butylphenyl esters of epoxy stearate are preferably used.

  Specific examples of (B8) epoxidized vegetable oil include epoxy compounds of vegetable oils such as soybean oil, linseed oil, and cottonseed oil.

  As the (B) epoxy compound, one of the above components (B1) to (B8) may be used alone, or two or more may be used in combination. In the present invention, heat / hydrolysis stability and friction characteristics can be further improved, so that (B1) phenyl glycidyl ether type epoxy compound, (B3) glycidyl ester type epoxy compound, (B6) alicyclic epoxy compound (B7) Epoxidized fatty acid monoesters are preferred, (B3) glycidyl ester type epoxy compounds and (B6) alicyclic epoxy compounds are more preferred.

  (B) When the epoxy compound is blended in the refrigerating machine oil composition of the present invention, the blending amount is not particularly limited, but normally, the refrigerating machine oil composition is based on the total amount (based on the total amount of base oil and all blended additives). It is desirable to add an epoxy compound in such an amount that the content is 0.1 to 5.0% by mass, more preferably 0.2 to 2.0% by mass.

  Moreover, it is preferable that the refrigerator oil composition of this invention further contains (C) phosphorothionate from the point which can further improve abrasion resistance. As the phosphorothionate, a compound represented by the following general formula (C-1) is preferably used.

In the general formula (C-1), R ⁶¹ , R ⁶² and R ⁶³ may be the same or different and each represents a hydrocarbon group having 1 to 24 carbon atoms. Specific examples of the hydrocarbon group having 1 to 24 carbon atoms represented by R ^{61 to} R ⁶³ include an alkyl group, a cycloalkyl group, an alkenyl group, an alkylcycloalkyl group, an aryl group, an alkylaryl group, and an arylalkyl group. Etc.

  Examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group. And alkyl groups such as hexadecyl group, heptadecyl group and octadecyl group (these alkyl groups may be linear or branched).

  As a cycloalkyl group, C5-C7 cycloalkyl groups, such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, can be mentioned, for example. Examples of the alkylcycloalkyl group include a methylcyclopentyl group, a dimethylcyclopentyl group, a methylethylcyclopentyl group, a diethylcyclopentyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a methylethylcyclohexyl group, a diethylcyclohexyl group, a methylcycloheptyl group, Examples thereof include an alkylcycloalkyl group having 6 to 11 carbon atoms such as a dimethylcycloheptyl group, a methylethylcycloheptyl group, and a diethylcycloheptyl group (the substitution position of the alkyl group with the cycloalkyl group is also arbitrary).

  Examples of the alkenyl group include butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl Alkenyl groups such as groups (these alkenyl groups may be linear or branched, and the position of the double bond is also optional).

  As an aryl group, aryl groups, such as a phenyl group and a naphthyl group, can be mentioned, for example. Examples of the alkylaryl group include tolyl group, xylyl group, ethylphenyl group, propylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, nonylphenyl group, and decylphenyl. Group, an alkylaryl group having 7 to 18 carbon atoms such as undecylphenyl group and dodecylphenyl group (the alkyl group may be linear or branched, and the substitution position on the aryl group is arbitrary). .

  Examples of the arylalkyl group include arylalkyl groups having 7 to 12 carbon atoms such as benzyl group, phenylethyl group, phenylpropyl group, phenylbutyl group, phenylpentyl group, and phenylhexyl group (these alkyl groups may be linear or branched). May be branched).

Hydrocarbon group of 1 to 24 carbon atoms represented by the ^R 61 ^{to R 63} is an alkyl group, an aryl group, preferably an alkyl aryl group, an alkyl group having 4 to 18 carbon atoms, having 7 to 24 carbon atoms An alkylaryl group and a phenyl group are more preferable.

  Specific examples of the phosphorothioate represented by the general formula (C-1) include tributyl phosphorothioate, tripentyl phosphorothioate, trihexyl phosphorothioate, triheptyl phosphorothioate, Trioctyl phosphorothioate, trinonyl phosphorothionate, tridecyl phosphorothionate, triundecyl phosphorothionate, tridodecyl phosphorothionate, tritridecyl phosphorothionate, tritetradecyl phosphorothionate , Tripentadecyl phosphorothionate, trihexadecyl phosphorothionate, triheptadecyl phosphorothionate, trioctadecyl phosphorothionate, trioleyl phosphorothionate, triphenyl phosphorothionate, Cresyl phosphorothioate, trixylenyl phosphorothioate, cresyl diphenyl phosphorothioate, xylenyl diphenyl phosphorothioate, tris (n-propylphenyl) phosphorothionate, tris (isopropylphenyl) phos Forothionate, tris (n-butylphenyl) phosphorothionate, tris (isobutylphenyl) phosphorothionate, tris (s-butylphenyl) phosphorothionate, tris (t-butylphenyl) phosphorothionate, etc. . Mixtures of these can also be used.

  The content of (C) phosphorothioate in the refrigerating machine oil composition of the present invention is preferably 0.01 to 5% by mass or less based on the total amount of the composition. By setting the content of the phosphorothionate within the above range, the wear resistance and stability (particularly thermal / oxidative stability) of the refrigerating machine oil composition can be further improved. More specifically, the amount of phosphorothioate added is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more from the viewpoint that a high level of wear resistance can be obtained. Further, even if the content is further increased, the effect of reducing wear corresponding to the content cannot be obtained, and on the contrary, it may cause the decrease in stability or the occurrence of corrosive wear. Preferably it is 5 mass% or less, More preferably, it is 3 mass% or less, More preferably, it is 1 mass% or less.

  The refrigerating machine oil composition of the present invention may further contain a phosphorus-based additive other than the phosphorothionate (hereinafter referred to as (D) phosphorus-based additive). (D) The phosphorus-based additive includes at least one phosphorus compound selected from the group consisting of phosphate esters, acidic phosphate esters, amine salts of acidic phosphate esters, chlorinated phosphate esters, and phosphite esters. preferable. These phosphorus compounds are esters of phosphoric acid or phosphorous acid with alkanols and polyether type alcohols or derivatives thereof.

Phosphate esters include tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, triundecyl phosphate, tridodecyl phosphate, tritridecyl phosphate, tritetradecyl phosphate , Tripentadecyl phosphate, trihexadecyl phosphate, triheptadecyl phosphate, trioctadecyl phosphate, trioleyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, etc .;
Examples of acidic phosphate esters include monobutyl acid phosphate, monopentyl acid phosphate, monohexyl acid phosphate, monoheptyl acid phosphate, monooctyl acid phosphate, monononyl acid phosphate, monodecyl acid phosphate, monoundecyl acid phosphate, monododecyl Acid phosphate, monotridecyl acid phosphate, monotetradecyl acid phosphate, monopentadecyl acid phosphate, monohexadecyl acid phosphate, monoheptadecyl acid phosphate, monooctadecyl acid phosphate, monooleyl acid phosphate, dibutyl acid phosphate, dipentyl acid , Dihexyl reed Dophosphate, diheptyl acid phosphate, dioctyl acid phosphate, dinonyl acid phosphate, didecyl acid phosphate, diundecyl acid phosphate, didodecyl acid phosphate, ditridecyl acid phosphate, ditetradecyl acid phosphate, dipentadecyl acid, dipentadecyl acid Hexadecyl acid phosphate, diheptadecyl acid phosphate, dioctadecyl acid phosphate, dioleyl acid phosphate, etc .;
Examples of the amine salt of acidic phosphate ester include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, Salts with amines such as dipentylamine, dihexylamine, diheptylamine, dioctylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, etc .;
Examples of the chlorinated phosphate ester include tris-dichloropropyl phosphate, tris-chloroethyl phosphate, tris-chlorophenyl phosphate, polyoxyalkylene bis [di (chloroalkyl)] phosphate, and the like;
As phosphites, dibutyl phosphite, dipentyl phosphite, dihexyl phosphite, diheptyl phosphite, dioctyl phosphite, dinonyl phosphite, didecyl phosphite, diundecyl phosphite, didodecyl phosphite, dioleyl Phosphite, diphenyl phosphite, dicresyl phosphite, tributyl phosphite, tripentyl phosphite, trihexyl phosphite, triheptyl phosphite, trioctyl phosphite, trinonyl phosphite, tridecyl phosphite, triundecyl phosphite Phyto, tridodecyl phosphite, trioleyl phosphite, triphenyl phosphite, tricresyl phosphite and the like. Mixtures of these can also be used.

  The content of the phosphorus additive (D) in the refrigerating machine oil composition of the present invention is preferably 0.01 to 5% by mass or less based on the total amount of the composition. By setting the content of the ester-based additive within the above range, the wear resistance and stability (particularly heat / oxidation stability) can be further improved. More specifically, the addition amount of the phosphorus-based additive is preferably 0.01% by mass or more, more preferably 0.1% by mass or more from the viewpoint that a high level of wear resistance can be obtained. Further, even if the content is further increased, the effect of reducing wear corresponding to the content cannot be obtained, and on the contrary, it may cause the decrease in stability or the occurrence of corrosion wear. Although it is 5 mass% or less, Preferably it is 4 mass% or less, More preferably, it is 3 mass% or less.

  Moreover, it is preferable that the refrigerating machine oil composition of this invention further contains (E) benzotriazole and / or its derivative (s). Inclusion of benzotriazole and / or a derivative thereof can further enhance the effect of improving wear resistance and friction characteristics.

  Benzotriazole is a compound represented by the following formula (E-1).

  Examples of the benzotriazole derivative include alkylbenzotriazole represented by the following general formula (E-2) and (alkyl) aminoalkylbenzotriazole represented by the following general formula (E-3). .

In the above formula (E-2), R ⁶⁴ represents a linear or branched alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group, and x is 1 to 3, preferably 1 Or the number of 2 is shown. Examples of R ⁶¹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. As the alkylbenzotriazole represented by the general formula (14), a compound in which R ⁶⁴ is a methyl group or an ethyl group and x is 1 or 2 is particularly preferable from the viewpoint of excellent antioxidant properties. Examples thereof include benzotriazole (tolyltriazole), dimethylbenzotriazole, ethylbenzotriazole, ethylmethylbenzotriazole, diethylbenzotriazole, and mixtures thereof.

In the above formula (E-2), R ⁶⁵ represents a linear or branched alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group, R ⁶⁶ represents a methylene group or an ethylene group, R ⁶⁷ and R ⁶⁸ may be the same or different and are a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms, preferably a linear or branched alkyl group having 1 to 12 carbon atoms. Represents an alkyl group, and y represents a number of 0 to 3, preferably 0 or 1. Examples of R ⁶⁵ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. As R ⁶⁷ and R ⁶⁸ , for example, a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a straight chain, or a A branched pentyl group, a linear or branched hexyl group, a linear or branched heptyl group, a linear or branched octyl group, a linear or branched nonyl group, a linear or branched decyl group, Linear or branched undecyl group, linear or branched dodecyl group, linear or branched tridecyl group, linear or branched tetradecyl group, linear or branched pentadecyl group, linear or branched Alkyl groups such as a hexadecyl group, a linear or branched heptadecyl group, and a linear or branched octadecyl group.

As the (alkyl) aminobenzotriazole represented by the above formula (E-3), R ⁶⁵ is a methyl group, y is 0 or 1, and R ⁶⁶ is methylene because it is particularly excellent in antioxidant properties. A dialkylaminoalkylbenzotriazole, dialkylaminoalkyltolyltriazole or a mixture thereof, which is a group or an ethylene group, and R ⁶⁷ and R ⁶⁸ are linear or branched alkyl groups having 1 to 12 carbon atoms, are preferably used. It is done. Examples of these dialkylaminoalkylbenzotriazoles include dimethylaminomethylbenzotriazole, diethylaminomethylbenzotriazole, di (linear or branched) propylaminomethylbenzotriazole, and di (linear or branched) butylaminomethylbenzotriazole. , Di (straight or branched) pentylaminomethylbenzotriazole, di (straight or branched) hexylaminomethylbenzotriazole, di (straight or branched) heptylaminomethylbenzotriazole, di (straight or branched) ) Octylaminomethylbenzotriazole, di (straight or branched) nonylaminomethylbenzotriazole, di (straight or branched) decylaminomethylbenzotriazole, di (straight or branched) undecylaminomethylbenzotriazole, (Linear or branched) dodecylaminomethylbenzotriazole; dimethylaminoethylbenzotriazole, diethylaminoethylbenzotriazole, di (linear or branched) propylaminoethylbenzotriazole, di (linear or branched) butylaminoethylbenzo Triazole, di (straight or branched) pentylaminoethylbenzotriazole, di (straight or branched) hexylaminoethylbenzotriazole, di (straight or branched) heptylaminoethylbenzotriazole, di (straight or branched) Branch) Octylaminoethylbenzotriazole, Di (straight or branched) nonylaminoethylbenzotriazole, Di (straight or branched) decylaminoethylbenzotriazole, Di (straight or branched) undecylaminoethylbenzotriazole , Di (linear or straight Branched) dodecylaminoethyl benzotriazole; dimethylaminomethyltolyltriazole, diethylaminomethyltolyltriazole, di (linear or branched) propylaminomethyltolyltriazole, di (straight or branched) butylaminomethyltolyltriazole, di ( Linear or branched) pentylaminomethyltolyltriazole, di (linear or branched) hexylaminomethyltolyltriazole, di (straight or branched) heptylaminomethyltolyltriazole, di (linear or branched) octylamino Methyltolyltriazole, di (linear or branched) nonylaminomethyltolyltriazole, di (straight or branched) decylaminomethyltolyltriazole, di (straight or branched) undecylaminomethyltolyltriazole, di (direct Chain or branch) Silaminomethyltolyltriazole; dimethylaminoethyltolyltriazole, diethylaminoethyltolyltriazole, di (linear or branched) propylaminoethyltolyltriazole, di (linear or branched) butylaminoethyltolyltriazole, di (linear or Branched) pentylaminoethyltolyltriazole, di (straight or branched) hexylaminoethyltolyltriazole, di (straight or branched) heptylaminoethyltolyltriazole, di (straight or branched) octylaminoethyltolyltriazole , Di (linear or branched) nonylaminoethyl tolyl triazole, di (linear or branched) decylaminoethyl tolyl triazole, di (linear or branched) undecylaminoethyl tolyl triazole, di (linear or branched) Branch) Dodecylamino Tilt Lil triazole; or mixtures thereof.

  The content of (E) benzotriazole and / or its derivative in the refrigerating machine oil composition of the present invention is arbitrary, but is preferably 0.001% by mass or more, more preferably 0.005% by mass, based on the total amount of the composition. That's it. When the amount is less than 0.001% by mass, the effect of improving wear resistance and frictional properties due to the inclusion of benzotriazole and / or its derivatives may be insufficient. Further, the content of benzotriazole and / or its derivative is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, based on the total amount of the composition. If it exceeds 1.0% by mass, the effect of improving the wear resistance and frictional properties corresponding to the content cannot be obtained, which may be economically disadvantageous.

  The refrigerating machine oil composition of the present invention may further contain an oily agent (hereinafter referred to as “(F) oily agent”). In addition, although the ester compound (A) according to the present invention has an oily effect, the “(F) oily agent” herein means an oily agent other than the ester compound (A), specifically, (F1) A monohydric alcohol oil agent, (F2) carboxylic acid oil agent, etc. are mentioned.

  (F1) As monohydric alcohol oil-based agent, C1-C24 monohydric alcohol, Preferably, it is C1-C12 monohydric alcohol, More preferably, C1-C8 monohydric alcohol is mentioned. The monohydric alcohol oily agent may be either a linear alcohol or a branched alcohol, and may be either a saturated alcohol or an unsaturated alcohol. The total number of carbon atoms in the monohydric alcohol oil-based agent is preferably 6 or more, more preferably 8 or more, and most preferably 10 or more, from the viewpoint of improving frictional properties and wear resistance. Moreover, since there exists a possibility that it may become easy to precipitate in a refrigerant | coolant atmosphere when a total carbon number is too large, 20 or less are preferable, 18 or less are more preferable, and 16 or less are the most preferable.

  Further, the (F2) carboxylic acid oily agent may be a monobasic acid or a polybasic acid, but a monobasic acid is preferable from the viewpoint of improving frictional properties and wear resistance. In addition, the number of carbon atoms of the carboxylic acid oil-based agent is preferably 6 or more, more preferably 8 or more, and most preferably 10 or more, from the viewpoint of improving frictional properties and wear resistance. Moreover, since there exists a possibility that it may precipitate easily in a refrigerant | coolant atmosphere when the total carbon number of a carboxylic acid oiliness agent is too large, 20 or less are preferable, 18 or less are more preferable, and 16 or less are the most preferable.

  In the refrigerating machine oil composition of the present invention, one of (F1) monohydric alcohol oil agent or (F2) carboxylic acid oil agent may be used alone, or two or more kinds may be used in combination. Good.

  The content of the (F) oil-based agent in the refrigerating machine oil composition of the present invention is arbitrary, but is preferably 0.01% by mass based on the total amount of the composition from the viewpoint of excellent effect of improving wear resistance and friction characteristics. As mentioned above, More preferably, it is 0.05 mass% or more, More preferably, it is 0.1 mass% or more. In addition, the content is preferably 10% by mass or less, based on the total amount of the composition, from the viewpoint of excellent precipitation prevention under a refrigerant atmosphere and low temperature, and heat / oxidation stability of the refrigerating machine oil composition. Preferably it is 7.5 mass% or less, More preferably, it is 5 mass% or less.

  Furthermore, in order to further improve the performance of the refrigerating machine oil composition in the present invention, a conventionally known refrigerating machine oil additive such as di-tert-butyl-p-cresol, bisphenol A or other phenolic type is used as necessary. Antioxidants, amine-based antioxidants such as phenyl-α-naphthylamine, N, N-di (2-naphthyl) -p-phenylenediamine, antiwear agents such as zinc dithiophosphate, chlorinated paraffin, sulfur compounds, etc. These extreme pressure agents, silicone-based antifoaming agents, viscosity index improvers, pour point depressants, cleaning dispersants, and other additives can be used alone or in combination. The total blending amount of these additives is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less on the basis of the total amount of the refrigerating machine oil composition (based on the total amount of the base oil and all the blending additives). .

The volume resistivity of the refrigerator oil composition of the present invention is not particularly limited, but is preferably 1.0 × 10 ⁹ Ω · cm or more. In particular, high electrical insulation tends to be required when used in a closed refrigerator. Here, the volume resistivity means a value [Ω · cm] at 25 ° C. measured in accordance with JIS C 2101 “Electrical Insulating Oil Test Method”.

  Furthermore, although the water content of the refrigerating machine oil composition of the present invention is not particularly limited, it is preferably 200 ppm or less, more preferably 100 ppm or less, and most preferably 50 ppm or less, based on the total amount of the refrigerating machine oil composition. In particular, when used for a closed type refrigerator, the water content is required to be low from the viewpoint of the influence on the heat and hydrolysis stability of oil and electrical insulation.

  Furthermore, the acid value of the refrigerating machine oil composition of the present invention is not particularly limited, but is preferably 0.1 mgKOH / g or less, more preferably 0 in order to prevent corrosion to the metal used in the refrigerating machine or piping. 0.05 mgKOH / g or less. The acid value here means a value [mg KOH / g] measured in accordance with JIS K 2501 “Petroleum products and lubricating oil-neutralization number test method”.

  Furthermore, the ash content of the refrigerating machine oil composition of the present invention is not particularly limited, but is preferably 100 ppm or less, more preferably, in order to increase the heat / hydrolysis stability of the refrigerating machine oil composition of the present invention and suppress the generation of sludge and the like. Can be 50 ppm or less. In the present invention, ash means a value [ppm] measured in accordance with JIS K 2272 “Testing method for ash and sulfated ash of crude oil and petroleum products”.

  Refrigerants used in the refrigerator using the refrigerator oil composition of the present invention include HFC refrigerants, fluorine-containing ether refrigerants such as perfluoroethers, non-fluorine-containing ether refrigerants such as dimethyl ether, carbon dioxide, ammonia, hydrocarbons, etc. These natural refrigerants may be used alone or as a mixture of two or more.

  Examples of the HFC refrigerant include hydrofluorocarbons having 1 to 3 carbon atoms, preferably 1 to 2 carbon atoms. Specifically, for example, difluoromethane (HFC-32), trifluoromethane (HFC-23), pentafluoroethane (HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134), 1, HFC such as 1,1,2-tetrafluoroethane (HFC-134a), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), or two or more of these And the like. These refrigerants are appropriately selected depending on the application and required performance. For example, HFC-32 alone; HFC-23 alone; HFC-134a alone; HFC-125 alone; HFC-134a / HFC-32 = 60 to 80 mass % / 40-20 mass% mixture; HFC-32 / HFC-125 = 40-70 mass% / 60-30 mass% mixture; HFC-125 / HFC-143a = 40-60 mass% / 60-40 mass % Mixture; HFC-134a / HFC-32 / HFC-125 = 60 wt% / 30 wt% / 10 wt% mixture; HFC-134a / HFC-32 / HFC-125 = 40-70 wt% / 15- 35 mass% / 5 to 40 mass% mixture; HFC-125 / HFC-134a / HFC-143a = 35-55 mass% / 1-15 mass% / 40-60 mass Mixtures of preferred examples include. More specifically, a mixture of HFC-134a / HFC-32 = 70/30 mass%; a mixture of HFC-32 / HFC-125 = 60/40 mass%; HFC-32 / HFC-125 = 50/50 mass % Mixture (R410A); HFC-32 / HFC-125 = 45/55 wt% mixture (R410B); HFC-125 / HFC-143a = 50/50 wt% mixture (R507C); HFC-32 / HFC -125 / HFC-134a = 30/10/60 wt% mixture; HFC-32 / HFC-125 / HFC-134a = 23/25/52 wt% mixture (R407C); HFC-32 / HFC-125 / HFC-134a = 25/15/60 mass% mixture (R407E); HFC-125 / HFC-134a / HFC-143a = Mixtures of 4/4/52 wt% (R404A), and the like.

  Examples of natural refrigerants include carbon dioxide, ammonia, and hydrocarbons. Here, as the hydrocarbon refrigerant, a gas refrigerant at 25 ° C. and 1 atm is preferably used. Specifically, it is an alkane, cycloalkane, alkene or a mixture thereof having 1 to 5 carbon atoms, preferably 1 to 4 carbon atoms. Specific examples include methane, ethylene, ethane, propylene, propane, cyclopropane, butane, isobutane, cyclobutane, methylcyclopropane, or a mixture of two or more thereof. Among these, propane, butane, isobutane or a mixture thereof is preferable.

  The refrigerating machine oil composition of the present invention is usually present in the form of a refrigerating machine fluid composition mixed with the refrigerant as described above in the refrigerating machine. The blending ratio of the refrigerating machine oil and the refrigerant in this fluid composition is not particularly limited, but the refrigerating machine oil is preferably 1 to 500 parts by weight, more preferably 2 to 400 parts by weight with respect to 100 parts by weight of the refrigerant.

  The refrigerating machine oil composition of the present invention can sufficiently reduce both the static friction coefficient and the dynamic friction coefficient in a sliding part such as a refrigerant compressor, and sufficiently reduces both the starting power and the power consumption during operation. Therefore, it is very useful in achieving a high level of energy saving. The refrigerating and air-conditioning equipment in which the refrigerating machine oil composition of the present invention is used is not particularly limited, and is suitably used for a refrigerating machine or a heat pump having a reciprocating or rotating open type, semi-hermetic or hermetic compressor. be able to. More specifically, such refrigeration equipment includes automotive air conditioners, dehumidifiers, refrigerators, refrigerated warehouses, vending machines, showcases, cooling equipment for chemical plants, residential air conditioners, packaged air conditioners, heat pumps for hot water supply, etc. Can be mentioned. Furthermore, the refrigerating machine oil composition of the present invention can be used in any type of compressor such as a reciprocating type, a rotary type, and a centrifugal type.

  As a configuration of a refrigerant circulation system in which the refrigerating machine oil composition of the present invention can be suitably used, typically, a refrigerant compressor, a condenser, an expansion mechanism, and an evaporator are connected in this order via respective flow paths. Examples thereof include a dryer provided in the flow path as necessary.

  As a refrigerant compressor, a motor composed of a rotor and a stator in a sealed container for storing refrigerating machine oil, a rotating shaft fitted to the rotor, and a compressor connected to the motor via the rotating shaft A high-pressure container type compressor in which high-pressure refrigerant gas discharged from the compressor unit stays in a sealed container, a motor composed of a rotor and a stator in a sealed container storing refrigerating machine oil, and rotation A low pressure in which a rotating shaft fitted to the child and a compressor unit connected to the motor via the rotating shaft are housed and high-pressure refrigerant gas discharged from the compressor unit is directly discharged out of the sealed container Examples thereof include a container type compressor.

  As an insulating film which is an electric insulation system material of a motor part, a crystalline plastic film having a glass transition point of 50 ° C. or more, specifically, for example, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyether ether ketone, polyethylene naphthalate, Polyamideimide, at least one insulating film selected from the group of polyimides, or a composite film in which a resin layer having a high glass transition temperature is coated on a film having a low glass transition temperature is less likely to cause deterioration of tensile strength characteristics and electrical insulation characteristics. Are preferably used. In addition, as a magnet wire used in the motor unit, an enamel coating having a glass transition temperature of 120 ° C. or higher, for example, a single layer such as polyester, polyesterimide, polyamide and polyamideimide, or a layer having a low glass transition temperature as a lower layer, Those having an enamel coating in which a high layer is composite-coated on the upper layer are preferably used. Examples of the composite enameled wire include polyester imide as a lower layer and polyamide imide as an upper layer (AI / EI), polyester as a lower layer and polyamide imide as an upper layer (AI / PE), and the like. .

  As the desiccant to be filled in the dryer, silicic acid and alkali metal aluminate composite salt having a pore diameter of 3.3 angstroms or less and a carbon dioxide absorption capacity at 25 ° C. carbon dioxide partial pressure of 250 mmHg is 1.0% or less. The synthetic zeolite is preferably used. Specific examples include trade names XH-9, XH-10, XH-11, and XH-600 manufactured by Union Showa Co., Ltd.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[Examples 1 to 45, Comparative Examples 1 to 13]
In Examples 1-45 and Comparative Examples 1-13, refrigerating machine oil compositions having the compositions shown in Tables 1-9 were prepared using the lubricant base oils and additives shown below, respectively. Table 10 shows the fatty acid composition of the lanolin fatty acid (I) used as the constituent carboxylic acid of the following additives A1 to A3.
(Lubricant base oil)
Base oil 1: tetraester of pentaerythritol and equimolar mixture of 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid (kinematic viscosity at 40 ° C .: 68.5 mm ² /
s, pour point: −25 ° C.)
Base oil 2: diester of 1,2-cyclohexanedicarboxylic acid and 2-ethylhexanol (kinematic viscosity at 40 ° C .: 15 mm ² / s, pour point: −40 ° C.)
Base oil 3: Random copolymer of vinyl ethyl ether and vinyl isobutyl ether (molar ratio of vinyl ethyl ether to vinyl isobutyl ether: 7/1, number average molecular weight: 900, kinematic viscosity at 40 ° C .: 68.5 mm ² / S, kinematic viscosity at 100 ° C .: 8 mm ² / s, pour point: −40 ° C.)
Base oil 4: Naphthenic mineral oil (kinematic viscosity at 40 ° C .: 56.6 mm ² / s, pour point: −3
0 ℃)
Base oil 5: Polypropylene glycol monomethyl ether (number average molecular weight: 1000, kinematic viscosity at 40 ° C .: 46 mm ² / s, kinematic viscosity at 100 ° C .: 10 mm ² / s, pour point: −40 ° C.)
Base oil 6: linear alkylbenzene (kinematic viscosity at 40 ° C. 27 mm ² / s, pour point −45 ° C. or lower)
Base oil 7: highly refined paraffinic mineral oil (kinematic viscosity at 40 ° C. 12 mm ² / s, pour point −20 ° C.)
Base oil 8: highly refined paraffinic mineral oil (kinematic viscosity at 40 ° C. 96 mm ² / s, pour point −17.5 ° C.)
(Ester compound (A))
A1: Diester of lanolin fatty acid (I) and pentaerythritol A2: Ester of lanolin fatty acid (I) and lauryl alcohol A3: Triester of lanolin fatty acid (I) and trimethylolpropane
(Additive for comparison)
B1: Butyl octoate B2: Butyl stearate
B3: Thiadiazole (other additives)
C1: glycidyl-2,2′-dimethyloctanoate C2: triphenylphosphorothionate C3: tricresyl phosphate.

  Next, the following evaluation tests were performed on the refrigerating machine oil compositions of Examples 1 to 45 and Comparative Examples 1 to 13.

[Frictional property evaluation test]
Using a reciprocating friction tester manufactured by PLINT, sliding while supplying the refrigerant at a flow rate of 10 L / h in a state where each refrigeration oil composition is present in the sliding part of the 1/2 inch SUJ2 steel ball and the SUJ2 disk. The friction coefficient of the moving part was recorded every second. The test conditions were a load of 100 N, a frequency of 10 Hz, and a test time of 11 minutes. Further, in this test, the following combinations are made depending on the type of the lubricating base oil contained in the refrigerator oil composition:
Base oil 1: R410A
Base oil 2: R134a
Base oil 3: R410A
Base oil 4: R22
Base oil 5: R410A
Base oil 6: R410A
Base oil 7: R600
Base oil 8: R290a
The refrigerant was selected and used.

  In the above test, the rise of the friction coefficient immediately after the start of the test was recorded as the static friction coefficient. Also, the average value of the friction coefficient for 10 minutes from the start of the test to the end of the test was taken as the dynamic friction coefficient. The obtained results are shown in Tables 1-9.

[Stability test]
In accordance with JIS K 2211, a shield glass tube test was performed using iron, copper, and aluminum as catalysts, and the presence or absence of sludge and a change in the appearance of the copper catalyst were observed after holding at 200 ° C. for 2 weeks. In this test, depending on the type of lubricating base oil contained in the refrigerator oil composition, the following combinations:
Base oil 1: R410A
Base oil 2: R134a
Base oil 3: R410A
Base oil 4: R22
Base oil 5: R410A
Base oil 6: R410A
Base oil 7: R600
Base oil 8: R290a
The refrigerant was selected and used so that The obtained results are shown in Tables 1-9. In the “Sludge” column of the table, A indicates that no sludge is observed, B indicates that a very small amount of sludge is recognized, C indicates that a very small amount of sludge is recognized, and D indicates a small amount of sludge. And E means that a large amount of sludge was observed. Also, in the column of “Copper catalyst change” in the table, A indicates that no change in the copper catalyst is observed, B indicates that a slight discoloration is observed, C indicates that a discoloration is observed, and D indicates blackening. And E means that corrosion was observed.

[Solubility test]
Evaluation of the solubility of the additive in the lubricating base oil was performed as follows. That is, the sample oil after the additive was dissolved in the lubricant base oil at a temperature of 60 ° C. and then cooled at 0 ° C. for 24 hours in the combination of the additive and the lubricant base oil shown in Tables 1-9. The appearance of was observed. In Comparative Examples 1 to 8, the base oils 1 to 8 were heated and cooled as described above, and the appearance of the sample oil was observed. The obtained results are shown in Tables 1-9. In the column of “Solubility” in the table, A is that the sample oil is colorless and transparent, B is slightly cloudy, C is slightly cloudy, D is cloudy, and D is floating. Each means.

Claims (1)

A predetermined lubricating base oil,
A refrigerating machine oil composition comprising an ester of a carboxylic acid containing hydroxycarboxylic acid and an alcohol.