JP2009074022A - Refrigerator oil and working fluid composition for refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerator oil and a working fluid composition for a refrigerator for achieving both of refrigerant compatibility and thermal and chemical stability in a refrigerating system using a fluoropropene refrigerant and/or a trifluoroiodomethane refrigerant. <P>SOLUTION: The refrigerator oil and the working fluid composition for a refrigerator contain alicyclic polyvalent carboxylates selected among esters A, B. The alicyclic polyvalent carboxylates are obtained by using the esters A, which are alicyclic dicarboxylates each having an alicyclic ring and two ester groups represented by -COOR<SP>1</SP>(wherein R<SB>1</SB>is a 1-30C hydrocarbon group) and connected to adjacent carbon atoms in the alicyclic ring, the esters B, which are alicyclic polyvalent carboxylic acids having an alicyclic ring and two or more carboxy groups, at least two of which are connected to the adjacent carbon atoms in the alicyclic ring, a compound having two or more hydroxy groups, and a compound having one hydroxy group. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  Due to the problem of ozone layer destruction in recent years, CFC (chlorofluorocarbon) and HCFC (hydrochlorofluorocarbon), which have been used as refrigerants in conventional refrigeration equipment, are subject to regulation, and HFC (hydrofluorocarbon) is used as a refrigerant instead. It is being done.

  When CFC or HCFC is used as a refrigerant, mineral oil or hydrocarbon oil such as alkylbenzene has been suitably used as the refrigeration oil. However, when the refrigerant is changed, the refrigeration oil used in the coexistence is compatible with the refrigerant, Refrigerating machine oil needs to be developed for each refrigerant in order to exhibit unpredictable behaviors such as lubricity, melt viscosity with refrigerant, and thermal and chemical stability. Therefore, as a refrigerating machine oil for HFC refrigerant, for example, polyalkylene glycol (for example, see Patent Document 1), ester (for example, see Patent Document 2), carbonate ester (for example, see Patent Document 3), Polyvinyl ether (for example, refer to Patent Document 4) has been developed.

Among HFC refrigerants, HFC-134a, which is standardly used as a refrigerant for car air conditioners, has zero ozone depletion potential (ODP), but has a high global warming potential (GWP). ing. Therefore, there is an urgent need to develop a refrigerant that replaces HFC-134a.

  Under such a background, as an alternative refrigerant to HFC-134a, both ODP and GWP are very small, non-flammable, and thermodynamic characteristics that are a measure of refrigerant performance are almost equivalent to HFC-134a. More than that, 1,3,3,3-tetrafluoropropene (HFO-1234ze), 2,3,3,3, -tetrafluoropropene (HFO-1234yf) or 1,2,3,3, -tetra The use of tetrafluoropropene refrigerants such as fluoropropene (HFO-1225ye) has been proposed. Furthermore, the use of a mixed refrigerant of tetrafluoropropene and trifluoroiodomethane has also been proposed.

On the other hand, it can be used with fluoropropene refrigerant or a mixed refrigerant of fluoropropene and saturated hydrofluorocarbon, saturated hydrocarbon having 3 to 5 carbon atoms, dimethyl ether, carbon dioxide, bis (trifluoromethyl) sulfide or trifluoroiodomethane. Refrigerating machine oils include mineral oils, alkylbenzenes, polyalphaolefins, polyalkylene glycols, monoesters, diesters, polyol esters, phthalate esters, alkyl ethers, ketones, carbonate esters, polyvinyl ethers. Refrigerating machine oil using the above has been proposed (see Patent Literature 5, Patent Literature 6, and 7).
Japanese Patent Laid-Open No. 02-242888 Japanese Patent Laid-Open No. 03-200895 Japanese Patent Laid-Open No. 03-217495 Japanese Patent Laid-Open No. 06-128578 International Publication WO2006 / 094303 Pamphlet JP-T-2006-512426 International Publication WO2005 / 103190 Pamphlet

  As described in Patent Documents 5, 6, and 7, in a refrigeration system using a fluoropropene refrigerant and / or a trifluoroiodomethane refrigerant, carbonization of mineral oil, alkylbenzene, or the like used in CFC or HCFC. It is considered that any of refrigerating machine oils such as hydrogen, polyalkylene glycol, polyol ester, and polyvinyl ether used in HFC are applicable. However, according to the study by the present inventors, a high level of refrigerant compatibility and thermal / chemical stability can be obtained simply by diverting conventional refrigeration oil used for refrigerants such as CFC and HCFC to the system as it is. Can not be achieved.

  The present invention has been made in view of such circumstances, and in a refrigeration system using a fluoropropene refrigerant and / or a trifluoroiodomethane refrigerant, both refrigerant compatibility and thermal / chemical stability are achieved. It is an object of the present invention to provide a refrigerating machine oil and a working fluid composition for a refrigerating machine that can be achieved at a high level.

  As a result of intensive studies to achieve the above object, the present inventors have used a fluoropropene refrigerant and / or trifluoroiodomethane by using an ester with a specific polyhydric alcohol having a specific fatty acid composition. The inventors have found that a refrigerating machine oil having sufficient thermal and chemical stability in the presence of a refrigerant and having sufficient compatibility with the refrigerant can be realized, and the present invention has been completed.

That is, the present invention relates to an alicyclic ring and the following general formula (1):
-COOR ¹ (1)
(Wherein R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms)
And two alicyclic dicarboxylic esters in which two of the ester groups are bonded to adjacent carbon atoms on the alicyclic ring, and the following compounds (a) to ( c):
(A) An alicyclic polyvalent carboxylic acid having an alicyclic ring and two or more carboxyl groups, wherein at least two of the carboxyl groups are bonded to adjacent carbon atoms on the alicyclic ring. Or a derivative thereof,
(B) a compound having two or more hydroxyl groups or a derivative thereof, and (c) a compound having one hydroxyl group or a derivative thereof,
At least one alicyclic polyvalent carboxylic acid ester selected from the group consisting of alicyclic polycarboxylic acid esters obtained by using a fluoropropene refrigerant and / or a trifluoroiodomethane refrigerant. A working fluid composition for a refrigerator is provided.

The present invention also provides an alicyclic ring and the following general formula (1):
-COOR ¹ (1)
(Wherein R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms)
And two alicyclic dicarboxylic esters in which two of the ester groups are bonded to adjacent carbon atoms on the alicyclic ring, and the following compounds (a) to ( c):
(A) An alicyclic polyvalent carboxylic acid having an alicyclic ring and two or more carboxyl groups, wherein at least two of the carboxyl groups are bonded to adjacent carbon atoms on the alicyclic ring. Or a derivative thereof,
(B) a compound having two or more hydroxyl groups or a derivative thereof, and (c) a compound having one hydroxyl group or a derivative thereof,
Containing at least one alicyclic polyvalent carboxylic acid ester selected from the group consisting of alicyclic polyvalent carboxylic acid esters obtained by using a fluoropropene refrigerant and / or trifluoroiodomethane refrigerant A refrigerating machine oil characterized by being used is provided.

  The working fluid composition for a refrigerator of the present invention includes 1,3,3,3-tetrafluoropropene (HFO-1234ze), 2,3,3,3, -tetrafluoropropene (HFO-1234yf) as a fluoropropene refrigerant. And at least one selected from 1,2,3,3, -tetrafluoropropene (HFO-1225ye).

  At least one fluoropropene refrigerant (hereinafter referred to as “refrigerant (A)”), saturated hydrofluorocarbon, hydrocarbon having 3 to 5 carbon atoms, dimethyl ether, carbon dioxide, bis (trifluoromethyl) sulfide, and trifluoride. It is preferable to contain at least one selected from iodomethane refrigerant (hereinafter referred to as “refrigerant (B)”).

Furthermore, in the mixed refrigerant of the refrigerant (A) and the refrigerant (B), 1,2,3,3,3-pentafluoropropene (HFC-1225ye), 1,3,3,3- Tetrafluoropropene (HFC-1234ze), 2,3,3,3-tetrafluoropropene (HFC-1234yf), 1,2,3,3-tetrafluoropropene (HFC1234ye) and 3,3,3-trifluoropropene At least one selected from (HFC-1243zf) is preferred;
Examples of saturated hydrofluorocarbons include difluoromethane (HFC-32), pentafluoroethane (HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,2-tetrafluoro. Ethane (HFC-134a), 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1 1,1,1,2,3,3-hexafluoropropane (HFC-236ea), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa), 1,1,1,3,3 -Selected from pentafluoropropane (HFC-245fa) and 1,1,1,3,3-pentafluorobutane (HFC-365mfc) Preferably one even without;
The hydrocarbon having 3 to 5 carbon atoms is preferably at least one selected from propane, normal butane, isobutane, 2-methylbutane and normal pentane.

  As described above, according to the present invention, in the refrigeration system using the fluoropropene refrigerant and / or the trifluoroiodomethane refrigerant, both refrigerant compatibility and thermal / chemical stability can be achieved at a high level. It becomes possible to provide a possible refrigerating machine oil and a working fluid composition for a refrigerating machine.

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

  The refrigerating machine oil of the present invention contains at least one alicyclic polyvalent carboxylic acid ester (hereinafter also referred to as “ester according to the present invention”) selected from the group consisting of the following esters A and B, and fluoro. Used with propene refrigerant and / or trifluoroiodomethane refrigerant.

Esters A: alicyclic ring and the following general formula (1):
-COOR ¹ (1)
(Wherein R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms)
The alicyclic dicarboxylic acid ester which has two ester groups represented by these, and two of these ester groups couple | bonded with the mutually adjacent carbon atom on an alicyclic ring.

Esters B: the following compounds (a) to (c):
(A) An alicyclic polyvalent carboxylic acid having an alicyclic ring and two or more carboxyl groups, wherein at least two of the carboxyl groups are bonded to adjacent carbon atoms on the alicyclic ring. Or an alicyclic polyvalent carboxylic acid ester obtained by using a derivative thereof, (b) a compound having two or more hydroxyl groups or a derivative thereof, and (c) a compound having one hydroxyl group or a derivative thereof.

  The working fluid composition for a refrigerator of the present invention contains the ester according to the present invention and a fluoropropene refrigerant and / or a trifluoroiodomethane refrigerant. Here, the working fluid composition for a refrigerator of the present invention includes an embodiment containing the refrigerator oil of the present invention and a fluoropropene refrigerant and / or a trifluoroiodomethane refrigerant.

  Examples of the alicyclic ring of the ester according to the present invention include a cyclopentane ring, a cyclopentene ring, a cyclohexane ring, a cyclohexene ring, a cycloheptane ring, and a cycloheptene ring, and a cyclohexane ring or a cyclohexene ring is preferable. Furthermore, among these, the cyclohexane ring is more preferable because it has a small increase in viscosity when used under long-term or harsh conditions, and the cyclohexene ring has a small increase in total acid value when used under long-term or harsh conditions. To more preferable.

  The refrigerating machine oil and the working fluid composition for a refrigerating machine according to the present invention include one or more alicyclic dicarboxylic acid esters (hereinafter referred to as “the present invention”) selected from the above esters A as the ester according to the present invention. In the case of containing "alicyclic dicarboxylic acid ester"), the alicyclic dicarboxylic acid ester has two ester groups represented by the above formula (1) together with the above alicyclic ring. When the number of the ester groups is one, the refrigerant compatibility and the heat / hydrolysis stability are insufficient. On the other hand, when the number of the ester groups is three or more, the low-temperature fluidity is insufficient.

  In the alicyclic dicarboxylic acid ester according to the present invention, the two ester groups represented by the formula (1) must be bonded to adjacent carbon atoms on the alicyclic ring. is there. When not bonded to adjacent carbon atoms on the alicyclic ring, the thermal / hydrolysis stability is insufficient.

  Furthermore, the alicyclic dicarboxylic acid ester according to the present invention can include both cis and trans isomers with respect to the orientation of two adjacent ester groups represented by the above formula (1). The molar ratio of the cis isomer to the trans isomer is preferably 20/80 to 80/20, more preferably 25/75 to 75/25, and more preferably 30/70 to 70/30. In addition, the alicyclic dicarboxylic acid ester according to the present invention may be used singly or as a mixture of two or more as described later. When the fluid composition contains two or more alicyclic dicarboxylic acid esters according to the present invention, the molar ratio of cis isomer to trans isomer refers to the molar ratio of all cis isomers to all trans isomers in the composition. .

R ¹ in the above formula (1) represents a hydrocarbon group having 1 to 30, preferably 2 to 24, more preferably 3 to 18 carbon atoms. Examples of the hydrocarbon group include an alkyl group, an alkenyl group, a cycloalkyl group, an alkylcycloalkyl group, an aryl group, an alkylaryl group, and an arylalkyl group. Among these, an alkyl group, a cycloalkyl group, or an alkylcycloalkyl group is preferable from the viewpoint of heat / hydrolysis stability.

  The alkyl group may be linear or branched, and specifically includes, for example, a linear or branched propyl group, linear or branched A butyl group, a linear or branched pentyl group, a linear or branched hexyl group, a linear or branched heptyl group, a linear or branched octyl group, a linear Linear or branched nonyl group, 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 a branched octadecyl group etc. are mentioned.

  Among these, as the linear alkyl group, those having 4 or more carbon atoms are preferable from the viewpoint of thermal / hydrolysis stability, and those having 18 or less carbon atoms are preferable from the viewpoint of refrigerant compatibility. The branched alkyl group is preferably one having 3 or more carbon atoms from the viewpoint of thermal / hydrolysis stability, and one having 18 or less carbon atoms is preferred from the viewpoint of refrigerant compatibility.

  Examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group, and a cyclohexyl group is preferable from the viewpoint of thermal and hydrolytic stability. The alkylcycloalkyl group is a group in which an alkyl group is bonded to a cycloalkyl group, but is preferably a group in which an alkyl group is bonded to a cyclohexyl group from the viewpoint of thermal and hydrolytic stability. Furthermore, the alkylcycloalkyl group preferably has a total carbon number of 6 or more from the viewpoint of thermal and hydrolysis stability, and preferably has a total carbon number of 10 or lower from the viewpoint of refrigerant compatibility and low-temperature fluidity.

The alicyclic dicarboxylic acid ester according to the present invention includes an alicyclic dicarboxylic acid having two carboxyl groups at adjacent carbon atoms on the alicyclic ring or an acid anhydride thereof and a monohydric alcohol (R ¹ —OH; R ¹ is using and represents) the same definition as R ¹ in the formula (1) can be obtained by the manufacturing method described below. In the present invention, at least two of R ¹ alicyclic dicarboxylic acid ester may be the same or different, but as the alcohol component, selected from the group consisting of (i) aliphatic alcohols having 1 to 5 carbon atoms 1 When at least one alcohol selected from the group consisting of a seed alcohol and (ii) an aliphatic alcohol having 6 to 18 carbon atoms is used, sufficient heat / hydrolysis stability and lubricity can be obtained, and further excellent It is preferable because refrigerant compatibility is obtained. When only one kind of the alcohol of the component (i) is used, the resulting alicyclic dicarboxylic acid ester is inferior in heat and hydrolysis stability and tends to have insufficient lubricity. Moreover, when only 1 type of alcohol of the said (ii) component is used, it exists in the tendency for the refrigerant | coolant compatibility of the obtained alicyclic dicarboxylic acid ester to become inadequate.

  Further, the alicyclic dicarboxylic acid ester according to the present invention is preferably obtained by using two or more kinds of alcohols, and among them, both the alcohol of the component (i) and the alcohol of the component (ii) are used. It is particularly preferred. Even when two or more kinds of the alcohol (i) are used alone, the resulting alicyclic dicarboxylic acid ester is inferior in heat and hydrolysis stability and tends to have insufficient lubricity. Moreover, even if it uses only 2 or more types of alcohol of (ii) component, the obtained alicyclic dicarboxylic acid ester exists in the tendency for compatibility with a refrigerant | coolant to become inadequate.

In the alicyclic dicarboxylic acid ester obtained using the alcohol components (i) and (ii), R ¹ derived from the aliphatic alcohol (i) is an alkyl group having 1 to 5 carbon atoms. From the viewpoint of decomposition stability, an alkyl group having 3 to 5 carbon atoms is preferred. The alkyl group having 1 to 5 carbon atoms may be linear or branched, but from the viewpoint of lubricity, the linear alkyl group is selected from refrigerant compatibility and heat. -From the viewpoint of hydrolysis stability, a branched alkyl group is preferred.

  Specific examples of the alkyl group having 1 to 5 carbon atoms derived from the alcohol component (i) include a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched chain, and the like. Butyl group, linear or branched pentyl group, etc., among these, n-butyl group and n-pentyl group are preferable from the viewpoint of lubricity, and from the viewpoint of thermal and hydrolytic stability. An iso-butyl group and an iso-pentyl group are preferable.

On the other hand, in the alicyclic dicarboxylic acid ester obtained using the alcohol components (i) and (ii), R ¹ derived from the aliphatic alcohol (ii) is an alkyl group having 6 to 18 carbon atoms. From the viewpoint of compatibility, an alkyl group having 6 to 12 carbon atoms is preferable, and an alkyl group having 7 to 9 carbon atoms is more preferable. The alkyl group having 6 to 18 carbon atoms may be linear or branched, but from the viewpoint of lubricity, the linear alkyl group is compatible with heat and heat. From the viewpoint of hydrolysis stability, a branched alkyl group is preferred. In addition, an alkyl group having more than 18 carbon atoms is not preferable because it is inferior in refrigerant compatibility and low-temperature fluidity.

  Specific examples of the alkyl group having 6 to 18 carbon atoms derived from the alcohol component (ii) include a linear or branched hexyl group, a linear or branched heptyl group, and a linear chain. Linear or branched octyl group, linear or branched nonyl group, linear or branched decyl group, linear or branched undecyl group, linear or branched chain Dodecyl group, linear or branched tridecyl group, linear or branched tetradecyl group, linear or branched pentadecyl group, linear or branched hexadecyl group, linear Or a branched heptadecyl group, a linear or branched octadecyl group, and the like. From the viewpoint of compatibility between lubricity and compatibility, an n-heptyl group, an n-octyl group, an n-nonyl group, n-decyl group is preferred Properly, compatibility and from the viewpoint of compatibility between thermal and hydrolytic stability iso- heptyl, 2-ethylhexyl, 3,5,5-trimethyl-hexyl group are preferable.

Preferred alicyclic dicarboxylic acid esters in the present invention are esters obtained by using the alcohol of the component (i) and the alcohol of the component (ii), and include the following.
(A-1) One of the two ester groups represented by the general formula (1) present in the same molecule is a group derived from the component (i), and the other is a group derived from the component (ii). Ester (A-2) An ester in which two ester groups represented by general formula (1) existing in the same molecule are groups derived from component (i) and two general formulas present in the same molecule A mixture of (A-3) (A-1) and (A-2) with an ester in which both ester groups represented by (1) are groups derived from component (ii).

  As the alicyclic dicarboxylic acid ester preferred in the present invention, any of the above (A-1) to (A-3) can be used, but from the viewpoint of thermal and hydrolytic stability, (A-1) or (A-3) is more preferable.

  In the case of (A-3), the content ratio of (A-1) and (A-2) is not particularly limited, but from the viewpoint of thermal and hydrolytic stability, (A-1) and (A -2) based on the total amount, (A-1) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, It is particularly preferably 20% by mass or more.

In a preferred alicyclic dicarboxylic acid ester in the present invention, the ratio of R ¹ in the formula (1), and R ¹ derived from (i) and R ¹ derived from the alcohol component of the component (ii) alcohol ( The molar ratio is not particularly limited, but may be within the range of 1/99 to 99/1 because it can satisfy all of lubricity, thermal / hydrolysis stability, and refrigerant compatibility at the same time. Further preferred.

Further, from the viewpoint of more emphasis on compatibility, (i) the ratio of the ^{R 1} derived from the alcohol ^{R 1} and (ii) component derived from the alcohol component (mole ratio) of 60 / 40-99 / 1 It is preferably in the range, more preferably in the range of 70/30 to 99/1, and most preferably in the range of 80/20 to 99/1. Further, from the viewpoint of placing more emphasis on thermal / hydrolysis stability and lubricity, the ratio is preferably in the range of 1/99 to 60/40, and preferably in the range of 1/99 to 50/50. Is more preferable, and most preferably in the range of 1/99 to 40/60.

  Of course, the alicyclic dicarboxylic acid ester according to the present invention may have one or more hydrocarbon groups bonded to carbon atoms on the alicyclic ring. As such a hydrocarbon group, an alkyl group is preferable, and a methyl group is particularly preferable from the viewpoint of compatibility.

  The alicyclic dicarboxylic acid ester according to the present invention has the above-described structure. Such an ester comprises a predetermined acid component and an alcohol component according to a conventional method, preferably an inert gas atmosphere such as nitrogen. Then, it is prepared by esterification with heating in the presence or absence of an esterification catalyst.

  The acid component of the alicyclic dicarboxylic acid ester is cycloalkane dicarboxylic acid, cycloalkene dicarboxylic acid or an acid anhydride thereof, and the two ester groups are bonded to adjacent carbon atoms on the alicyclic ring. Which can be used as one or a mixture of two or more. Specifically, 1,2-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, 1-cyclohexene-1,2-dicarboxylic acid, 3-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl -1,2-Cyclohexanedicarboxylic acid, 3-methyl-4-cyclohexene-1,2-dicarboxylic acid, 4-methyl-4-cyclohexene-1,2-dicarboxylic acid and acid anhydrides thereof are disclosed. Among these, from the viewpoint of suppressing an increase in viscosity when the prepared ester is used under long-term or severe conditions, 1,2-cyclohexanedicarboxylic acid, 3-methyl-1,2-cyclohexanedicarboxylic acid, 4- Methyl-1,2-cyclohexanedicarboxylic acid and acid anhydrides thereof are preferable, and among them, 1,2-cyclohexanedicarboxylic acid is more preferable because of higher compatibility. On the other hand, from the viewpoint of suppressing an increase in the total acid value when used under long-term or harsh conditions, 4-cyclohexene-1,2-dicarboxylic acid, 1-cyclohexene-1,2-dicarboxylic acid, 4-methyl -1,2-cyclohexanedicarboxylic acid, 3-methyl-4-cyclohexene-1,2-dicarboxylic acid, 4-methyl-4-cyclohexene-1,2-dicarboxylic acid and acid anhydrides thereof are preferred, among these 4-Cyclohexene-1,2-dicarboxylic acid is more preferred because it is more excellent in compatibility and heat / hydrolysis stability. In the present invention, when the above alicyclic dicarboxylic acid is used as the acid component, the molar ratio of the cis isomer to the trans isomer in the alicyclic dicarboxylic acid is preferably 20/80 to 80/20. Preferably it is 25 / 75-75 / 25, More preferably, it is 30 / 70-70 / 30.

  There is no restriction | limiting in particular in the manufacturing method of said alicyclic dicarboxylic acid and its anhydride, It can obtain by a conventionally well-known method. Specifically, for example, 4-cyclohexene-1,2-dicarboxylic acid can be obtained by reacting butadiene and maleic anhydride in a benzene solvent at 100 ° C.

  The alcohol component of the alicyclic dicarboxylic acid ester according to the present invention includes a linear alcohol having 1 to 18 carbon atoms, a branched alcohol having 3 to 18 carbon atoms, or a cycloalcohol having 5 to 10 carbon atoms. Is mentioned. Specifically, methanol, ethanol, linear or branched propanol (including n-propanol, 1-methylethanol, etc.), linear or branched butanol (n-butanol, 1-methylpropanol) , Including 2-methylpropanol), linear or branched pentanol (including n-pentanol, 1-methylbutanol, 2-methylbutanol, 3-methylbutanol, etc.), linear or branched Branched hexanol (including n-hexanol, 1-methylpentanol, 2-methylpentanol, 3-methylpentanol, etc.), linear or branched heptanol (n-heptanol, 1-methylhexanol, 2-methylhexanol, 3-methylhexanol, 4-methylhexanol, 5-methylhexanol 2,4-dimethylpentanol, etc.), linear or branched octanol (including n-octanol, 2-ethylhexanol, 1-methylheptanol, 2-methylheptanol, etc.), linear Or branched nonanol (including n-nonanol, 1-methyloctanol, 3,5,5-trimethylhexanol, 1- (2′-methylpropyl) -3-methylbutanol, etc.), linear or branched Decanol (including n-decanol, iso-decanol, etc.), linear or branched undecanol (including n-undecanol, etc.), linear or branched dodecanol (n-dodecanol, iso- Dodecanol, etc.), linear or branched tridecanol, linear or branched tetradecanol (n-te Including radecanol, iso-tetradecanol, etc.), linear or branched pentadecanol, linear or branched hexadecanol (including n-hexadecanol, iso-hexadecanol, etc.) ), Linear or branched heptadecanol, linear or branched octadecanol (including n-octadecanol, iso-octadecanol, etc.), cyclohexanol, methylcyclohexanol, dimethyl And cyclohexanol.

  In the present invention, as described above, among these alcohol components, (i) at least one alcohol selected from the group consisting of aliphatic alcohols having 1 to 5 carbon atoms, and (ii) those having 6 to 18 carbon atoms. It is preferable to use at least one alcohol selected from the group consisting of aliphatic alcohols. Examples of the component (i) alcohol include linear alcohols having 1 to 5 carbon atoms and branched alcohols having 3 to 5 carbon atoms. Specific examples include methanol, ethanol, n-propanol, n-butanol, n-pentanol, iso-propanol, iso-butanol, sec-butanol, and iso-pentanol. From the viewpoint, n-butanol and n-pentanol are preferable, and from the viewpoint of thermal and hydrolytic stability, iso-butanol and iso-pentanol are preferable.

  On the other hand, examples of the alcohol of the component (ii) include straight chain alcohols having 6 to 18 carbon atoms or branched chain alcohols having 6 to 18 carbon atoms. Specifically, for example, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol Nord, iso-hexanol, 2-methylhexanol, 1-methylheptanol, 2-methylheptanol, iso-heptanol, 2-ethylhexanol, 2-octanol, iso-octanol, 3,5,5-trimethylhexanol, iso -Decanol, iso-tetradecanol, iso-hexadecanol, iso-octadecanol, 2,6-dimethyl-4-heptanol and the like, and n-heptanol from the viewpoint of compatibility between lubricity and compatibility, n-octanol, n-nonanol, n-de Nord preferably, from the viewpoint of compatibility and thermal and hydrolytic stability of both iso- heptanol, 2-ethylhexanol, 3,5,5-trimethyl hexanol are preferred.

  In performing the esterification reaction using the acid component and the alcohol component, the alcohol component is used in an amount of, for example, 1.0 to 1.5 equivalents, preferably 1.05 to 1.2 equivalents per equivalent of the acid component. It is done.

  Furthermore, in place of the acid component and the alcohol component, the alicyclic dicarboxylic acid ester according to the present invention is transesterified using a lower alcohol ester of the acid component and / or an acetate ester or propionate ester of the alcohol. It is also possible to obtain

  Specific examples of the esterification catalyst used in the present invention include Lewis acids such as aluminum derivatives, tin derivatives and titanium derivatives; alkali metal salts such as sodium alkoxide and potassium alkoxide; paratoluenesulfonic acid, methanesulfonic acid, Examples thereof include sulfonic acids such as sulfuric acid. The usage-amount of an esterification catalyst is about 0.1-1 mass% with respect to the total amount of the acid component and alcohol component which are raw materials, for example. Of these, Lewis acids such as aluminum derivatives, tin derivatives and titanium derivatives are preferred in consideration of the effect on the heat and hydrolysis stability of the obtained alicyclic dicarboxylic acid esters. Among them, tin derivatives are preferred in terms of reaction efficiency. Particularly preferred.

  The temperature at the time of esterification is exemplified by 150 to 230 ° C. The reaction is usually completed in 3 to 30 hours.

  After completion of the esterification reaction, excess raw materials are distilled off under reduced pressure or normal pressure, and then the ester can be purified by a conventional purification method such as adsorption purification treatment such as solvent extraction, vacuum distillation, activated carbon treatment, etc. it can.

  In the above esterification reaction, by selectively using an alicyclic dicarboxylic acid having a molar ratio of cis form and trans form of 20/80 to 80/20 as the acid component of the raw material, the cis form and the trans form are used. The alicyclic dicarboxylic acid ester whose molar ratio is 20/80 to 80/20 can be obtained. When an alicyclic carboxylic acid anhydride is used as the acid component of the raw material, the alicyclic cis-trans isomer has a molar ratio within the above range by performing the reaction under predetermined reaction conditions. The formula dicarboxylic acid ester can be obtained. Furthermore, what mixed previously obtained cis type | mold alicyclic dicarboxylic acid ester and trans type | mold alicyclic dicarboxylic acid ester so that those molar ratios may exist in the said range can also be used.

  Further, the refrigerating machine oil and the working fluid composition for the refrigerating machine of the present invention are one or two or more alicyclic polyvalent carboxylic acid esters selected from the esters B (hereinafter referred to as “alicyclic polyhydric acid according to the present invention”). (Also referred to as a “valent carboxylic acid ester”), the alicyclic polyvalent carboxylic acid or derivative thereof used as the acid component of the alicyclic polyvalent carboxylic acid ester according to the present invention includes an alicyclic ring. It is necessary to have a formula ring and two or more carboxyl groups (hereinafter collectively referred to as a compound (a) including a derivative of an alicyclic polyvalent carboxylic acid). When there is one carboxyl group, refrigerant compatibility and heat / hydrolysis stability are insufficient. The number of carboxyl groups is not particularly limited, but is preferably 4 or less, more preferably 3 or less, and most preferably 2. When the number of carboxyl groups exceeds the upper limit, the low temperature fluidity of the resulting alicyclic polycarboxylic acid ester tends to be insufficient.

  Further, at least two of the carboxyl groups of the compound (a) according to the present invention must be bonded to adjacent carbon atoms on the alicyclic ring. When there are no two carboxyl groups bonded to carbon atoms adjacent to each other on the alicyclic ring, the resulting alicyclic polycarboxylic acid ester has insufficient heat and hydrolysis stability.

  When the compound (a) used in the present invention is an alicyclic polyvalent carboxylic acid, the configuration of the carboxyl group is not particularly limited, and the carboxyl group bonded to adjacent carbon atoms on the alicyclic ring is not limited. The orientation may be either a cis body or a trans body. Moreover, a cis body or a trans body may be used independently and may be used as a mixture of both. However, from the viewpoint of heat / hydrolysis stability, a cis body is preferable, and from the viewpoint of achieving both heat / hydrolysis stability and lubricity, a trans body is preferable. Moreover, when using the mixture of a cis body and a trans body, the molar ratio becomes like this. Preferably it is 20 / 80-80 / 20, More preferably, it is 25 / 75-75 / 25, More preferably, it is 30 / 70-70 / 30 is there. When the molar ratio of the cis form to the trans form is within the above range, it is possible to achieve both higher lubricity and higher heat / hydrolysis stability.

  Examples of the alicyclic polyvalent carboxylic acid include cycloalkane polycarboxylic acid, cycloalkene polycarboxylic acid and the like in which at least two carboxyl groups are bonded to adjacent carbon atoms on the alicyclic ring. These may be used alone or as a mixture of two or more. Specific examples of the alicyclic polycarboxylic acid having such a structure include 1,2-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, and 1-cyclohexene-1,2-dicarboxylic acid. 3-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 3-methyl-4-cyclohexene-1,2-dicarboxylic acid, 4-methyl-4-cyclohexene-1, 2-dicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid are disclosed. Among these, from the viewpoint of suppressing an increase in viscosity when the obtained alicyclic polyvalent carboxylic acid ester is used under long-term or severe conditions, 1,2-cyclohexanedicarboxylic acid, 3-methyl-1,2- Preferred are cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, while long term or harsh conditions From the viewpoint of suppressing an increase in the total acid value during use of 4-cyclohexene-1,2-dicarboxylic acid, 1-cyclohexene-1,2-dicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 3-methyl-4-cyclohexene-1,2-dicarboxylic acid, 4-methyl-4-cyclohexene-1,2-di Carboxylic acid is preferred.

  The compound (a) according to the present invention may be a derivative of an alicyclic polyvalent carboxylic acid, such as an acid anhydride, an ester, or an acid halide. Examples of the alicyclic polycarboxylic acid derivative used in the present invention include acid anhydrides, esters, acid halides, and the like of the compounds exemplified in the description of the alicyclic polycarboxylic acid.

  There is no restriction | limiting in particular in the manufacturing method of alicyclic polyhydric carboxylic acid and its derivative (s), What was obtained by arbitrary methods can be used. Specifically, for example, 4-cyclohexene-1,2-dicarboxylic acid can be obtained by reacting butadiene and maleic anhydride in a benzene solvent at 100 ° C.

  Moreover, the compound (b) which is one of the alcohol components of the alicyclic polycarboxylic acid ester according to the present invention needs to have two or more hydroxyl groups. Such compounds (b) include, for example, polyhydric alcohols, polyhydric phenols, polyhydric amino alcohols and condensates thereof, and compounds in which the hydroxyl groups of these compounds are esterified with a lower carboxylic acid such as acetic acid. (Hereinafter collectively referred to as compound (b) including derivatives of compounds having two or more hydroxyl groups). Among these, it is preferable to use a polyhydric alcohol or a condensate thereof because refrigerant compatibility, electrical insulation, and thermal stability tend to be further improved.

  The polyhydric alcohol suitably used in the present invention preferably has 2 to 10 carbon atoms, more preferably 2 to 8 carbon atoms, and an ether bond may be contained in the molecule. Specific examples of such polyhydric alcohols include ethylene glycol, propylene glycol, butylene glycol, 1,3-butanediol, 1,4-butanediol, glycerin, neopentyl glycol, trimethylolethane, and trimethylol. Propane, trimethylol butane, pentaerythritol, 1,3,5, -pentanetriol, sorbitol, sorbitan, isosorbide, sorbitol glycerin condensate, adonitol, arabitol, xylitol, mannitol, xylose, arabinose, ribose, rhamnose, glucose, fructose , Galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, raffinose, gentianose, Jitosu, methyl glucoside, and the like of these partially etherified product is.

  Moreover, the polyhydric alcohol condensate suitably used in the present invention is preferably obtained by condensing a polyhydric alcohol having 2 to 10 carbon atoms, more preferably 2 to 8 carbon atoms. From the viewpoint of electrical characteristics and ease of production, the condensation degree of the polyhydric alcohol condensate is preferably 2 to 10, more preferably 2 to 5. Specific examples of the polyhydric alcohol condensate having such a structure include diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, pentapropylene glycol, Dibutylene glycol, tributylene glycol, tetrabutylene glycol, pentabylene glycol, diglycerin, triglycerin, tetraglycerin, pentaglycerin, di (neopentylglycol), tri (neopentylglycol), tetra (neopentylglycol), penta (Neopentyl glycol), di (trimethylolethane), tri (trimethylolethane), tetra (trimethylolethane), penta ( Limethylolethane), di (trimethylolpropane), tri (trimethylolpropane), tetra (trimethylolpropane), penta (trimethylolpropane), di (trimethylolbutane), tri (trimethylolbutane), tetra (trimethylolbutane) Examples thereof include methylol butane), penta (trimethylol butane), di (pentaerythritol), tri (pentaerythritol), tetra (pentaerythritol), penta (pentaerythritol) and the like.

  The compound (b) according to the present invention may be a derivative in which the hydroxyl group is esterified with a lower carboxylic acid as described above. As such derivatives, acetates or propionates of the compounds exemplified in the description of the polyhydric alcohol and polyhydric alcohol condensate are preferably used.

  Moreover, the compound (c) which is the other of the alcohol components of the alicyclic polyvalent carboxylic acid ester according to the present invention needs to have one hydroxyl group. Examples of such compounds (c) include monohydric alcohols, monohydric phenols, monohydric amino alcohols, and compounds in which these hydroxyl groups are esterified with a lower carboxylic acid such as acetic acid (hereinafter including derivatives). (Collectively referred to as compound (c)). Among these, it is preferable to use a linear monohydric alcohol having 1 to 18 carbon atoms, a branched monohydric alcohol having 3 to 18 carbon atoms, or a monovalent cycloalcohol having 5 to 10 carbon atoms. Specific examples of such a monohydric alcohol include methanol, ethanol, linear or branched propanol (including n-propanol, 1-methylethanol, etc.), linear or branched butanol. (Including n-butanol, 1-methylpropanol, 2-methylpropanol, etc.), linear or branched pentanol (n-pentanol, 1-methylbutanol, 2-methylbutanol, 3-methylbutanol, etc.) ), Linear or branched hexanol (including n-hexanol, 1-methylpentanol, 2-methylpentanol, 3-methylpentanol, etc.), linear or branched heptanol (including n-heptanol, 1-methylhexanol, 2-methylhexanol, 3-methylhexanol, 4-methylhexanol , 5-methylhexanol, 2,4-dimethylpentanol, etc.), linear or branched octanol (n-octanol, 2-ethylhexanol, 1-methylheptanol, 2-methylheptanol, etc.) Linear) or branched nonanol (including n-nonanol, 1-methyloctanol, 3,5,5-trimethylhexanol, 1- (2′-methylpropyl) -3-methylbutanol, etc.), Linear or branched decanol (including n-decanol, iso-decanol, etc.), linear or branched undecanol (including n-undecanol, etc.), linear or branched dodecanol (including n-dodecanol, iso-dodecanol, etc.), linear or branched tridecanol, linear or branched tetradecane (Including n-tetradecanol, iso-tetradecanol, etc.), linear or branched pentadecanol, linear or branched hexadecanol (n-hexadecanol, iso -Hexadecanol etc.), linear or branched heptadecanol, linear or branched octadecanol (including n-octadecanol, iso-octadecanol etc.), cyclo Examples include hexanol, methylcyclohexanol, and dimethylcyclohexanol.

  Further, as the compound (c), (c-I) at least one monohydric alcohol selected from the group consisting of aliphatic monohydric alcohols having 1 to 5 carbon atoms, and (c-II) carbon atoms having 6 to 18 carbon atoms. When a mixture of at least one monohydric alcohol selected from the group consisting of aliphatic monohydric alcohols is used, sufficiently high heat / hydrolysis stability and lubricity, and better refrigerant compatibility can be obtained. Particularly preferred. When only one kind of the alcohol of the component (c-I) is used, the resulting alicyclic dicarboxylic acid ester is inferior in heat and hydrolysis stability and tends to have insufficient lubricity. Moreover, when only 1 type of alcohol of the said (c-II) component is used, it exists in the tendency for the refrigerant | coolant compatibility of the obtained alicyclic dicarboxylic acid ester to become inadequate.

  Further, the alicyclic polycarboxylic acid ester according to the present invention is preferably obtained by using two or more kinds of alcohols as the compound (c), and among them, the alcohol (c-I) and (c -II) It is particularly preferred to use both the component alcohol. Even if only two or more alcohols of the component (c-I) are used as the compound (c), the resulting alicyclic dicarboxylic acid ester tends to be inferior in heat and hydrolysis stability and insufficient in lubricity. is there. Moreover, even if it uses only 2 or more types of alcohol of (c-II) component as a compound (c), the alicyclic dicarboxylic acid ester obtained tends to become inadequate with a refrigerant | coolant.

  As the alcohol of the component (c-I), a linear alcohol having 1 to 5 carbon atoms or a branched alcohol having 3 to 5 carbon atoms, specifically, for example, methanol, ethanol, n-propanol, Examples include n-butanol, n-pentanol, iso-propanol, iso-butanol, sec-butanol, and iso-pentanol. Among these, n-butanol and n-pentanol are preferable from the viewpoint of lubricity, and iso-butanol and iso-pentanol are preferable from the viewpoint of thermal / hydrolysis stability.

  On the other hand, as the alcohol of the component (c-II), a linear alcohol having 6 to 18 carbon atoms or a branched alcohol having 6 to 18 carbon atoms, specifically, for example, n-hexanol, n- Heptanol, n-octanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol, n-tetradecanol, n-hexadecanol, n-octadecanol, iso-hexanol, 2-methylhexanol, 1 -Methylheptanol, 2-methylheptanol, iso-heptanol, 2-ethylhexanol, 2-octanol, iso-octanol, 3,5,5-trimethylhexanol, iso-decanol, iso-tetradecanol, iso-hexa Decanol, iso-octadecanol, 2,6-dimethyl- - heptanol, and the like. Among these, n-heptanol, n-octanol, n-nonanol and n-decanol are preferable from the viewpoint of compatibility between lubricity and compatibility, and from the viewpoint of compatibility between compatibility and thermal / hydrolysis stability. Iso-heptanol, 2-ethylhexanol, and 3,5,5-trimethylhexanol are preferred.

  When the (c-I) component and the (c-II) component are used in combination, the molar ratio of the (c-I) component to the (c-II) component is not particularly limited, but lubricity, heat / hydrolysis stability Therefore, it is preferable that the ratio is in the range of 1:99 to 99: 1 because both the compatibility and the refrigerant compatibility can be satisfied at the same time. Further, from the viewpoint of placing more emphasis on compatibility, the above ratio is preferably in the range of 60:40 to 99: 1, more preferably in the range of 70:30 to 99: 1, and 80:20. Most preferably, it is in the range of ~ 99: 1. Furthermore, from the viewpoint of placing more emphasis on thermal / hydrolysis stability and lubricity, the above ratio is preferably in the range of 1:99 to 60:40, and in the range of 1:99 to 50:50. More preferably, it is most preferably in the range of 1:99 to 40:60.

  The compound (c) according to the present invention may be a derivative in which a hydroxyl group is esterified with a lower carboxylic acid. As such derivatives, acetates, propionates and the like of the compounds exemplified in the description of the monohydric alcohol are preferably used.

In the present invention, it is particularly preferable to combine the following compounds (a ′), (b ′) and (c ′) as the compounds (a), (b) and (c).
(A ′) 1,2-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid and one kind selected from the group consisting of acid anhydrides, esters and acid halides thereof (b ′) ethylene glycol, propylene 1 type selected from the group consisting of glycol, butylene glycol, glycerin, neopentyl glycol, diethylene glycol, dipropylene glycol, dibutylene glycol, diglycerin, dineopentyl glycol, and esterified products thereof,
(C ′) n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, iso-butanol, iso-pentanol, iso-hexanol, iso-heptanol, 2-ethylhexanol, 3,5,5-trimethylhexanol, mixed alcohol of n-butanol and n-hexanol, mixed alcohol of n-butanol and n-heptanol, mixed alcohol of n-butanol and n-octanol, a mixed alcohol of n-butanol and n-nonanol, a mixed alcohol of n-butanol and n-decanol, a mixed alcohol of n-butanol and iso-hexanol, a mixed alcohol of n-butanol and iso-heptanol, n- Butanol and 2-ethyl Mixed alcohol of hexanol, mixed alcohol of n-butanol and 3,5,5-trimethylhexanol, mixed alcohol of iso-butanol and n-hexanol, mixed alcohol of iso-butanol and n-heptanol, iso-butanol And n-octanol mixed alcohol, iso-butanol and n-nonanol mixed alcohol, iso-butanol and n-decanol mixed alcohol, iso-butanol and iso-hexanol mixed alcohol, iso-butanol and iso A mixed alcohol of heptanol, a mixed alcohol of iso-butanol and 2-ethylhexanol, a mixed alcohol of iso-butanol and 3,5,5-trimethylhexanol, n-pentanol and n-hexanol Mixed alcohol, n-pentanol and n-heptanol mixed alcohol, n-pentanol and n-octanol mixed alcohol, n-pentanol and n-nonanol mixed alcohol, n-pentanol and n -Mixed alcohol of decanol, mixed alcohol of n-pentanol and iso-hexanol, mixed alcohol of n-pentanol and iso-heptanol, mixed alcohol of n-pentanol and 2-ethylhexanol, n-pen Mixed alcohol of tanol and 3,5,5-trimethylhexanol, mixed alcohol of iso-pentanol and n-hexanol, mixed alcohol of iso-pentanol and n-heptanol, iso-pentanol and n-octanol Mixed alcohol, iso-pe Mixed alcohol of tanol and n-nonanol, mixed alcohol of iso-pentanol and n-decanol, mixed alcohol of iso-pentanol and iso-hexanol, mixed alcohol of iso-pentanol and iso-heptanol, iso -One kind selected from the group consisting of a mixed alcohol of pentanol and 2-ethylhexanol, a mixed alcohol of iso-pentanol and 3,5,5-trimethylhexanol, and esterified products thereof.

  When the esterification reaction is performed using the compounds (a) to (c), the total amount of the compound (b) and the compound (c) which are alcohols is (a) an alicyclic polyvalent carboxylic acid or its Usually 1.0 to 1.5 equivalents, preferably 1.05 to 1.2 equivalents are used per equivalent of anhydride.

  Further, the molar ratio of the compound (b) to the compound (c) is not particularly limited, but it is possible to satisfy all of lubricity, heat / hydrolysis stability and refrigerant compatibility at the same time. It is preferably in the range of 99 to 99: 1. Furthermore, from the viewpoint of placing more emphasis on compatibility, the ratio is preferably in the range of 1:99 to 80:20, more preferably in the range of 5:95 to 70:30, and 10:90. Most preferably, it is in the range of ˜60: 40.

  The alicyclic polycarboxylic acid ester according to the present invention comprises an acid component (a) and an alcohol component (b) and (c) according to a conventional method, preferably in an inert gas atmosphere such as nitrogen. It is prepared by esterification with heating in the presence or absence of a catalyst.

  Further, when a lower alcohol ester of an alicyclic polycarboxylic acid is used as the compound (a), or when an acetic acid ester, propionic acid ester or the like of the alcohol is used as the compound (b) or (c), a transesterification reaction is performed. Thus, it is possible to obtain an alicyclic polyvalent dicarboxylic acid ester according to the present invention.

  Examples of the esterification catalyst in the above esterification reaction include Lewis acids such as aluminum derivatives, tin derivatives and titanium derivatives; alkali metal salts such as sodium alkoxide and potassium alkoxide; sulfonic acids such as paratoluenesulfonic acid, methanesulfonic acid and sulfuric acid Among them, Lewis acids such as aluminum derivatives, tin derivatives, titanium derivatives and the like are preferable in consideration of the effect on the thermal / hydrolysis stability of the obtained alicyclic dicarboxylic acid ester, Of these, tin derivatives are particularly preferred from the viewpoint of reaction efficiency. Moreover, the usage-amount of the said esterification catalyst is about 0.1-1 mass% with respect to the total amount of the acid component and alcohol component which are raw materials, for example.

  The reaction temperature in the above esterification reaction is exemplified by 150 to 230 ° C., and the reaction is usually completed in 3 to 30 hours.

  In addition, after the esterification reaction is completed, excess raw materials are distilled off under reduced pressure or normal pressure, and then the ester is purified by a conventional purification method such as adsorption purification treatment such as solvent extraction, vacuum distillation, activated carbon treatment, etc. be able to.

In the above esterification reaction, for example, the polyvalent carboxylic acid used as the compound (a) or a derivative thereof has two carboxyl groups, and the compound used as the compound (b) has two hydroxyl groups. In general, the reaction product is usually represented by the following formulas (D) to (H):
R ³ —X—R ² —X—R ³ (D)
R ³ —X—R ² —X—R ² —X—R ³ (E)




R ³ —X—R ³ (H)
(In the above formula, X represents an alicyclic dicarboxylic acid residue derived from compound (a), R ² represents a residue of a compound having two hydroxyl groups derived from compound (b), and R ³ represents A compound represented by the formula (c) represents a residue of a compound having one hydroxyl group derived from the compound (c).

  The alicyclic dicarboxylic acid residue represented by X in the above formulas (D) to (H) is on an alicyclic ring such as a cyclopentane ring, cyclopentene ring, cyclohexane ring, cyclohexene ring, cycloheptane ring, cycloheptene ring, etc. In which a carboxyl group is bonded to carbon atoms adjacent to each other. Such an alicyclic dicarboxylic acid residue is preferably a group having a cyclohexane ring and a cyclohexene ring. Furthermore, among these, a group having a cyclohexane ring is more preferable because of a small increase in viscosity when used under long-term or harsh conditions, and a group having a cyclohexene ring is a total acid group when used under long-term or harsh conditions. It is more preferable because the increase in value is small.

In the above formulas (D) to (H), the group represented by R ² is a residue obtained by removing the hydroxyl group from the compound having two hydroxyl groups used as the compound (b).

When a dihydric alcohol is used as the compound (b), R ² may contain an ether bond, but its carbon number is preferably 2 to 10, and more preferably 2 to 8. Specific examples of such R ² include residues obtained by removing a hydroxyl group from compounds such as ethylene glycol, propylene glycol, butylene glycol, 1,3-butanediol, 1,4-butanediol, and neopentyl glycol. Is mentioned.

When a condensate of a dihydric alcohol is used as the compound (b), R ² is a condensate having 2 to 10 carbon atoms (more preferably 2 to 8) and a degree of condensation of 2 to 10 (more preferably 2 to 5). It is preferable that these are residues. Specific examples of such R ² include diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, pentapropylene glycol, dibutylene glycol, and tributylene. Examples include residues obtained by removing hydroxyl groups from compounds such as glycol, tetrabutylene glycol, pentabylene glycol, di (neopentyl glycol), tri (neopentyl glycol), tetra (neopentyl glycol), penta (neopentyl glycol) and the like. .

The group represented by R ³ in the above formulas (D) to (H) is a residue obtained by removing a hydroxyl group from a compound having one hydroxyl group used as the compound (c). R ³ preferably has 1 to 30 carbon atoms, more preferably 2 to 24 carbon atoms, and still more preferably 3 to 18 carbon atoms. Examples of such R ³ include an alkyl group, an alkenyl group, a cycloalkyl group, an alkylcycloalkyl group, an aryl group, an alkylaryl group, and an arylalkyl group. Among these, an alkyl group, a cycloalkyl group, or an alkylcycloalkyl group is preferable from the viewpoint of heat / hydrolysis stability.

Of the groups represented by R ³ , the alkyl group may be linear or branched. Specific examples of the alkyl group having 3 to 18 carbon atoms include a linear or branched propyl group, a linear or branched butyl group, a linear or branched pentyl group, Linear or branched hexyl group, linear or branched heptyl group, linear or branched octyl group, linear or branched nonyl group, linear or branched Linear decyl group, linear or branched undecyl group, linear or branched dodecyl group, linear or branched tridecyl group, linear or branched tetradecyl group, straight Examples thereof include a linear or branched pentadecyl group, a linear or branched hexadecyl group, a linear or branched heptadecyl group, and a linear or branched octadecyl group.

  Among these alkyl groups, as the linear alkyl group, those having 4 or more carbon atoms are preferable from the viewpoint of thermal and hydrolytic stability, and those having 18 or less carbon atoms are preferable from the viewpoint of refrigerant compatibility. The branched alkyl group is preferably one having 3 or more carbon atoms from the viewpoint of thermal / hydrolysis stability, and one having 18 or less carbon atoms is preferred from the viewpoint of refrigerant compatibility.

Among the groups represented by R ³ , examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and the like, and a cyclohexyl group is preferable from the viewpoint of thermal / hydrolysis stability. The alkylcycloalkyl group is a group in which an alkyl group is bonded to a cycloalkyl group, but is preferably a group in which an alkyl group is bonded to a cyclohexyl group from the viewpoint of thermal and hydrolytic stability. Furthermore, the alkylcycloalkyl group preferably has a total carbon number of 6 or more from the viewpoint of thermal and hydrolysis stability, and preferably has a total carbon number of 10 or lower from the viewpoint of refrigerant compatibility and low-temperature fluidity.

When a mixed alcohol of the monohydric alcohols of the above (c-I) and (c-II) is used as the compound (c), the component (c-I) among R ^{3 in} the obtained compounds (D) to (H) The alkyl group derived from is an alkyl group having 1 to 5 carbon atoms, and preferably an alkyl group having 3 to 5 carbon atoms from the viewpoint of thermal and hydrolytic stability.

  The alkyl group having 1 to 5 carbon atoms derived from the component (c-I) may be linear or branched, but is linear from the viewpoint of lubricity. The alkyl group is preferably a branched alkyl group from the viewpoints of refrigerant compatibility and heat / hydrolysis stability. Specific examples of such an alkyl group include a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, a linear or branched chain, and the like. A pentyl group etc. are mentioned, Among these, an n-butyl group and an n-pentyl group are preferable from the viewpoint of lubricity, and an iso-butyl group and an iso-pentyl group are preferable from the viewpoint of thermal / hydrolysis stability.

On the other hand, among R ³ in the above formulas (D) to (H), the alkyl group derived from the component (c-II) is an alkyl group having 6 to 18 carbon atoms, but from the viewpoint of compatibility, it has 6 carbon atoms. -12 alkyl groups are preferable, and alkyl groups having 7 to 9 carbon atoms are more preferable. The alkyl group having 6 to 18 carbon atoms may be linear or branched, but from the viewpoint of lubricity, the linear alkyl group is compatible with heat and heat. From the viewpoint of hydrolysis stability, a branched alkyl group is preferred. In the case of an alkyl group having more than 18 carbon atoms, the refrigerant compatibility and the low temperature fluidity are inferior.

  Specific examples of the alkyl group having 6 to 18 carbon atoms derived from the component (c-II) include a linear or branched hexyl group, a linear or branched heptyl group, and a linear chain. Linear or branched octyl group, linear or branched nonyl group, linear or branched decyl group, linear or branched undecyl group, linear or branched chain Dodecyl group, linear or branched tridecyl group, linear or branched tetradecyl group, linear or branched pentadecyl group, linear or branched hexadecyl group, linear Or a branched heptadecyl group, a linear or branched octadecyl group, and the like. From the viewpoint of compatibility between lubricity and compatibility, n-heptyl group, n-octyl group, n-nonyl group, n -Decyl group is preferred and compatible From the standpoint of thermal and hydrolytic stability of incompatible iso- heptyl, 2-ethylhexyl, 3,5,5-trimethyl-hexyl group are preferable.

Further, when the alcohol of the component (cI) and the alcohol of the component (c-II) are used as the compound (c), the compounds represented by the above formulas (D), (E), and (H) are the following ( The thing of the aspect shown to B-1)-(B-3) is included.
(B-1) One of the two alkyl groups represented by the general formula R ³ existing in the same molecule is a group derived from the (c-I) component, and the other is derived from the (c-II) component. ester is a group which ester groups represented by two general formulas R ³ present in the ester (B-2) in the same molecule is a group derived from both (c-I) component, is present in the same molecule two general formulas ester group represented by ^{R 3} together (c-II) a mixture of esters which are derived from group component mixture of (B-3) and (B-1) and (B-2).

  In the present invention, any one of the above (B-1) to (B-3) can be used, but from the viewpoint of thermal and hydrolytic stability, (B-1) or (B -3) is preferred.

  In the case of (B-3), the content ratio of (B-1) and (B-2) is not particularly limited, but from the viewpoint of thermal and hydrolytic stability, (B-1) and Based on the total amount of (B-2), (B-1) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. It is preferably 20% by mass or more.

Furthermore, the above formula (D), (E), of ^{R 3} of (H), and ^{R 3} derived from the alcohols ^{R 3} and (c-II) component derived from an alcohol of (c-I) component The ratio (molar ratio) is not particularly limited, but it should be in the range of 1:99 to 99: 1 because all of lubricity, heat / hydrolysis stability and refrigerant compatibility can be satisfied simultaneously. Is preferred. Furthermore, from the viewpoint of placing more emphasis on compatibility, the above ratio is preferably in the range of 60:40 to 99: 1, more preferably in the range of 70:30 to 99: 1, and 80: Most preferably, it is in the range of 20-99: 1. Further, from the viewpoint of placing more emphasis on thermal / hydrolysis stability and lubricity, the above ratio is preferably in the range of 1:99 to 60:40, and in the range of 1:99 to 50:50. Is more preferable, and most preferably in the range of 1:99 to 40:60.

  In the present invention, when the compound obtained in the above esterification reaction is represented by the above formulas (D) to (H), among the compounds represented by the above formulas (D) to (G) 1 type may be used independently and may be used as a 2 or more types of mixture among the compounds represented by said formula (D)-(H). In addition, the alicyclic polyvalent carboxylic acid ester according to the present invention includes only the compound represented by the above formula (H) without including any of the compounds represented by the above formulas (D) to (G). In such a case, the balance between high viscosity and refrigerant compatibility is inferior.

Moreover, when the alicyclic polycarboxylic acid ester according to the present invention is a mixture of two or more of the compounds represented by the above formulas (D) to (H), the content ratio of each compound is arbitrary. Although not particularly limited, the content based on the total amount of the mixture is preferably as follows from the viewpoint of the balance between refrigerant compatibility and various performances and ease of production.
(D): 0 to 100 mol%, preferably 1 to 99 mol%, more preferably 5 to 95 mol%,
(E): 0 to 100 mol%, preferably 1 to 90 mol%, more preferably 2 to 80 mol%,
(F): 0 to 100 mol%, preferably 1 to 99 mol%, more preferably 5 to 95 mol%,
(G): 0 to 100 mol%, preferably 1 to 90 mol%, more preferably 2 to 80 mol%,
(H): 0 to 90 mol%, preferably 1 to 80 mol%, more preferably 5 to 75 mol%.

  Here, although the esterification reaction using the compound (a) as an acid component and the compounds (b) and (c) as an alcohol component has been described, the alicyclic polycarboxylic acid according to the present invention is described. Esters are produced as long as the structure of the acid component in the molecule is derived from the compound (a) and the structure of the alcohol component is derived from the compound (b) and / or (c). The method is not limited to the method based on the above esterification reaction. For example, an aromatic polyvalent carboxylic acid obtained by an esterification reaction between an aromatic polyvalent carboxylic acid having two carboxyl groups at adjacent carbon atoms of an aromatic ring and the alcohols of the compounds (b) and (c) above. It is possible to obtain the desired alicyclic polyvalent carboxylic acid ester by obtaining an ester and further subjecting the obtained aromatic polyvalent carboxylic acid ester to hydrogenation treatment (hydrogenation treatment).

  In addition, in the alicyclic polyvalent carboxylic acid ester thus obtained, it goes without saying that one or more hydrocarbon groups may be bonded to the carbon atom on the alicyclic ring. As such a hydrocarbon group, an alkyl group is preferable, and a methyl group is particularly preferable from the viewpoint of compatibility.

  In the refrigerating machine oil of the present invention, the ester content according to the present invention is not particularly limited. It is preferably contained, more preferably 70% by mass or more, still more preferably 80% by mass or more, and most preferably 90% by mass or more.

  The refrigerating machine oil of the present invention may be composed only of the ester according to the present invention, but may further contain a base oil other than the ester and various additives. The working fluid composition for a refrigerator of the present invention may further contain a base oil and various additives other than the ester according to the present invention. In the following description, the contents of base oils and additives other than esters according to the present invention are shown on the basis of the total amount of refrigerating machine oil, but the contents of these components in the refrigerating machine fluid composition are When the total amount of machine oil is used as a reference, it is desirable to select so as to be within a preferable range described later.

  Base oils other than esters according to the present invention include mineral oils, olefin polymers, naphthalene compounds, hydrocarbon oils such as alkylbenzenes, and ester base oils other than esters according to the present invention (monoesters, polyol esters, etc.), Synthetic oils containing oxygen such as polyglycol, polyvinyl ether, ketone, polyphenyl ether, silicone, polysiloxane, perfluoroether may be used in combination. Among the above, as the synthetic oil containing oxygen, polyol ester, polyglycol, and polyvinyl ether are preferably used.

  In addition, since the refrigerating machine oil and the working fluid composition for refrigerating machines of the present invention contain the ester according to the present invention, they can be suitably used even in a state where no additives are added, but various additives are blended as necessary. Can also be used.

  In order to further improve the wear resistance and load resistance of the refrigerating machine oil and the working fluid composition for the refrigerating machine of the present invention, phosphoric acid ester, acidic phosphoric acid ester, thiophosphoric acid ester, amine salt of acidic phosphoric acid ester, chlorine At least one phosphorus compound selected from the group consisting of phosphorylated phosphates and phosphites can be blended. These phosphorus compounds are esters of phosphoric acid or phosphorous acid with alkanols and polyether type alcohols or derivatives thereof.

  Specifically, for example, as phosphate ester, 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, xyl Examples include rhenyl diphenyl phosphate.

  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 Examples include hexadecyl acid phosphate, diheptadecyl acid phosphate, dioctadecyl acid phosphate, dioleyl acid phosphate, and the like.

  Examples of thiophosphates include tributyl phosphorothioate, tripentyl phosphorothioate, trihexyl phosphorothioate, triheptyl phosphorothionate, trioctyl phosphorothionate, trinonyl phosphorothionate, tridecyl phosphorothioate. Phosphorothioate, triundecyl phosphorothionate, tridodecyl phosphorothionate, tritridecyl phosphorothionate, tritetradecyl phosphorothionate, tripentadecyl phosphorothionate, trihexadecyl phosphorothionate, Triheptadecyl phosphorothioate, trioctadecyl phosphorothionate, trioleyl phosphorothionate, triphenyl phosphorothionate, tricresyl phosphorothionate, trixyl Cycloalkenyl phosphorothionate, cresyldiphenyl phosphorothionate, like carboxymethyl Les sulfonyl diphenyl phosphorothionate.

  Examples of the amine salt of acidic phosphate ester include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, Examples thereof include salts with amines such as dipentylamine, dihexylamine, diheptylamine, dioctylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine.

  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 can be mentioned. A mixture of these can also be used.

  When the refrigerating machine oil and the working fluid composition for a refrigerating machine of the present invention contain the phosphorus compound, the content of the phosphorus compound is not particularly limited, but is based on the total amount of refrigerating machine oil (based on the total amount of base oil and all blended additives). It is preferable that it is 0.01-5.0 mass%, and it is more preferable that it is 0.02-3.0 mass%. In addition, the said phosphorus compound may be used individually by 1 type, and may use 2 or more types together.

  Further, the refrigerating machine oil and the working fluid composition for the refrigerating machine according to the present invention include a phenyl glycidyl ether type epoxy compound, an alkyl glycidyl ether type epoxy compound, and a glycidyl ester type epoxy compound in order to further improve the thermal and chemical stability. , An allyl oxirane compound, an alkyl oxirane compound, an alicyclic epoxy compound, an epoxidized fatty acid monoester, and an epoxidized vegetable oil can be contained.

  Specific examples of the phenyl glycidyl ether type epoxy compound include phenyl glycidyl ether and alkylphenyl glycidyl ether. Examples of the alkylphenyl glycidyl ether herein include 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.

  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 diglycidyl ether, Examples thereof include trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1,6-hexanediol diglycidyl ether, sorbitol polyglycidyl ether, polyalkylene glycol monoglycidyl ether, and polyalkylene glycol diglycidyl ether.

  Specific examples of the glycidyl ester type epoxy compound include phenyl glycidyl ester, alkyl glycidyl ester, alkenyl glycidyl ester, etc., and preferable ones are glycidyl-2,2-dimethyloctanoate, glycidyl benzoate, glycidyl acrylate. And glycidyl methacrylate.

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

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

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

  Specific examples of the epoxidized fatty acid monoester include esters of an epoxidized fatty acid having 12 to 20 carbon atoms with an alcohol or phenol having 1 to 8 carbon atoms or an alkylphenol. In particular, butyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl, phenyl and butylphenyl esters of epoxy stearate are preferably used.

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

  Among these epoxy compounds, phenyl glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, alicyclic epoxy compounds and epoxidized fatty acid monoesters are preferred. Of these, phenyl glycidyl ether type epoxy compounds and glycidyl ester type epoxy compounds are more preferred, and phenyl glycidyl ether, butylphenyl glycidyl ether, alkyl glycidyl esters or mixtures thereof are particularly preferred.

  When the refrigerating machine oil and the working fluid composition for a refrigerating machine of the present invention contain the epoxy compound, the content of the epoxy compound is not particularly limited, but is 0.1 to 5.0% by mass based on the total amount of the refrigerating machine oil. It is preferably 0.2 to 2.0% by mass. In addition, the said epoxy compound may be used individually by 1 type, and may use 2 or more types together.

  In addition, the refrigerating machine oil and the working fluid composition for the refrigerating machine of the present invention can contain conventionally known additives for refrigerating machine oil as necessary in order to further enhance the performance. Examples of such additives include phenolic antioxidants such as di-tert-butyl-p-cresol and bisphenol A, phenyl-α-naphthylamine, N, N-di (2-naphthyl) -p-phenylenediamine, and the like. Amine-based antioxidants, anti-wear agents such as zinc dithiophosphate, extreme pressure agents such as chlorinated paraffin and sulfur compounds, oil-based agents such as fatty acids, antifoaming agents such as silicones, metal inertness such as benzotriazole Agents, viscosity index improvers, pour point depressants, detergent dispersants and the like. These additives may be used individually by 1 type, and may be used in combination of 2 or more type. The content of these additives is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total amount of refrigerating machine oil.

The kinematic viscosity of the refrigerating machine oil of the present invention is not particularly limited, but the kinematic viscosity at 40 ° C. is preferably 3 to 1000 mm ² / s, more preferably 4 to 500 mm ² / s, and most preferably 5 to 400 mm ² / s. can do. The kinematic viscosity at 100 ° C. is preferably 1 to 100 mm ² / s, more preferably ² to 50 mm ² / s.

The volume resistivity of the refrigerating machine oil of the present invention is not particularly limited, but is preferably 1.0 × 10 ¹² Ω · cm or more, more preferably 1.0 × 10 ¹³ Ω · cm or more, and most preferably 1.0. × 10 ¹⁴ Ω · cm or more can be set. In particular, when it is used for a hermetic refrigerator, high electrical insulation tends to be required. In the present invention, the volume resistivity means a value at 25 ° C. measured in accordance with JIS C 2101 “Electrical insulating oil test method”.

  Further, the water content of the refrigerating machine oil of the present invention is not particularly limited, but can be preferably 200 ppm or less, more preferably 100 ppm or less, and most preferably 50 ppm or less based on the total amount of refrigerating machine oil. In particular, when it is used for a hermetic type refrigerator, the moisture content is required to be small from the viewpoint of the influence on the thermal / chemical stability and electrical insulation of the refrigerator oil.

  Further, the acid value of the refrigerating machine oil of the present invention is not particularly limited, but the ester oil contained in the refrigerating machine oil for fluoropropene refrigerant of the present invention is used to prevent corrosion to the metal used in the refrigerating machine or piping. In order to prevent decomposition, it is preferably 0.1 mgKOH / g or less, more preferably 0.05 mgKOH / g or less. In addition, in this invention, an acid value means the acid value measured based on JISK 2501 "Petroleum products and lubricating oil-neutralization value test method".

Further, the ash content of the refrigerating machine oil of the present invention is not particularly limited, but is preferably 100 ppm or less, more preferably, in order to increase the thermal and chemical stability of the fluoropropene refrigerant refrigerating machine oil and suppress the generation of sludge and the like. It can be 50 ppm or less. In the present invention, ash refers to JISK 2272 “Method for testing ash and sulfated ash of crude oil and petroleum products”.
This means the ash value measured according to the above.

  The refrigerating machine oil of the present invention is used together with a fluoropropene refrigerant and / or a trifluoroiodomethane refrigerant, and the working fluid composition for a refrigerating machine of the present invention has a fluoropropene refrigerant and / or trifluoroiodinated. It contains methane refrigerant. The refrigerant used in the present invention may be either a fluoropropene refrigerant or a trifluoroiodomethane refrigerant, or may be a mixed refrigerant of a fluoropropene refrigerant and a trifluoroiodomethane refrigerant. Good.

  As the fluoropropene refrigerant, fluoropropene having 3 to 5 fluorine atoms is preferable. 1,2,3,3,3-pentafluoropropene (HFC-1225ye), 1,3,3,3-tetrafluoropropene (HFC) -1234ze), 2,3,3,3-tetrafluoropropene (HFC-1234yf), 1,2,3,3-tetrafluoropropene (HFC1234ye), and 3,3,3-trifluoropropene (HFC-1243zf) 1) or a mixture of two or more of them. From the viewpoint of the physical properties of the refrigerant, one or more selected from HFC-1225ye, HFC-1234ze, and HFC-1234yf are preferable.

  In addition, the refrigerant used in the present invention may be a mixed refrigerant of a fluoropropene refrigerant and a trifluoroiodomethane refrigerant and another refrigerant. Examples of other refrigerants include HFC refrigerants, fluorine-containing ether refrigerants such as bar fluoroethers, and natural refrigerants such as dimethyl ether, ammonia, and hydrocarbons.

  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, 1,1,2-tetrafluoroethane (HFC-134a), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 1 1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,1,2,3,3-hexafluoropropane (HFC-236ea), 1,1,1,3 , 3,3-hexafluoropropane (HFC-236fa), 1,1,1,3,3-pentafluoropropane (HFC-245fa), and 1,1 1,3,3-pentafluorobutane (HFC-365mfc), or a mixture of two or more thereof. 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 Such as a mixture 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.

  Of the HFC refrigerants, saturated hydrofluorocarbons include difluoromethane (HFC-32), pentafluoroethane (HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1. , 1,2-Tetrafluoroethane (HFC-134a), 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,1,2,3,3-hexafluoropropane (HFC-236ea), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa), 1, 1,1,3,3-pentafluoropropane (HFC-245fa), 1,1,1,3,3-pentafluorobutane (HFC-365 fc) is preferably one or a mixture of two or more, and from the viewpoint of refrigerant physical properties, HFC-32, HFC-125, HFC-134a, HFC-152a, or HFC-32 and HFC- A mixture of 134a is preferred.

  The hydrocarbon refrigerant is preferably a hydrocarbon having 3 to 5 carbon atoms, specifically, for example, methane, ethylene, ethane, propylene, propane, cyclopropane, normal butane, isobutane, cyclobutane, methylcyclopropane, 2-methylbutane. , Normal pentane, or a mixture of two or more thereof. Among these, gas at 25 ° C. and 1 atm is preferably used, and propane, normal butane, isobutane, 2-methylbutane or a mixture thereof is preferable.

  Specific examples of the fluorine-containing ether-based refrigerant include HFE-134p, HFE-245mc, HFE-236mf, HFE-236me, HFE-338mcf, HFE-365mcf, HFE-245mf, HFE-347mmy, HFE-347mcc, HFE-125, HFE-143m, HFE-134m, HFE-227me, etc. are mentioned, These refrigerant | coolants are suitably selected according to a use or required performance.

  When the refrigerant used in the present invention is a mixed refrigerant, the mixed refrigerant is at least one selected from fluoropropene refrigerant (hereinafter referred to as “refrigerant (A)”), saturated hydrofluorocarbon, 3 to 3 carbon atoms. 5 hydrocarbons, dimethyl ether, carbon dioxide, bis (trifluoromethyl) sulfide and at least one selected from trifluoroiodomethane refrigerant (hereinafter referred to as “refrigerant (B)”). .

  Further, when the refrigerant used in the present invention is a mixed refrigerant containing the refrigerant (A) and the refrigerant (B), the mixed refrigerant is preferably an azeotropic mixture, but has physical properties necessary as a refrigerant. If it does, it does not need to be an azeotrope in particular, The mixing ratio of both is preferably 1:99 to 99: 1, more preferably 5:95 to 95: 5.

  Furthermore, when the refrigerant used in the present invention is a mixed refrigerant containing the refrigerant (A) and the refrigerant (B), the mixed refrigerant is an HFC refrigerant other than a fluoropropene refrigerant or a saturated hydrofluorocarbon, or a bar fluoroether. And other natural refrigerants such as ammonia or hydrocarbons other than hydrocarbons having 3 to 5 carbon atoms.

  The refrigerating machine oil of the present invention usually exists in the form of a refrigerating machine fluid composition mixed with a fluoropropene refrigerant and / or a trifluoroiodomethane refrigerant or a mixed refrigerant as described above in a refrigerating and air-conditioning apparatus. Yes. The mixing ratio of the refrigerating machine oil and the refrigerant in the composition and the mixing ratio of the refrigerating machine oil and the refrigerant in the working fluid composition for a refrigerating machine of the present invention are not particularly limited, but the refrigerating machine oil is preferable with respect to 100 parts by mass of the refrigerant. Is 1 to 500 parts by mass, more preferably 2 to 400 parts by mass.

  The refrigerating machine oil and the working fluid composition for a refrigerating machine of the present invention are preferably used in an air conditioner, a refrigerator, or an open or sealed car air conditioner having a reciprocating or rotating hermetic compressor. Further, the refrigerating machine oil and the working fluid composition for the refrigerating machine of the present invention are preferably used for a dehumidifier, a hot water heater, a freezer, a freezer / refrigerator warehouse, a vending machine, a showcase, a cooling device for a chemical plant, and the like. Furthermore, the refrigerating machine oil and the working fluid composition for a refrigerating machine of the present invention are also preferably used for those having a centrifugal compressor.

  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 1-48, Comparative Examples 1-4]
In Examples 1 to 48 and Comparative Examples 1 to 4, refrigeration oils were prepared using base oils 1 to 48 shown below. Various properties of the obtained refrigerating machine oil are shown in Tables 1-11.
[Base oil]
Base oil 1: ester obtained from 1,2-cyclohexanedicarboxylic acid and i-heptanol (ester 1: 100% by mass, cis / trans ratio (molar ratio): 55/45)
Base oil 2: ester obtained from 1,2-cyclohexanedicarboxylic acid and 2-ethylhexanol (ester 2: 100% by mass, cis / trans ratio (molar ratio): 58/42)
Base oil 3: ester obtained from 1,2-cyclohexanedicarboxylic acid and 3,5,5-trimethylhexanol (ester 3: 100% by mass, cis / trans ratio (molar ratio): 39/61)
Base oil 4: ester obtained from 1,2-cyclohexanedicarboxylic acid and i-nonanol (ester 4: 100% by mass, cis / trans ratio (molar ratio): 66:34)
Base oil 5: ester obtained from 1,2-cyclohexanedicarboxylic acid and i-decanol (ester 5: 100% by mass, cis / trans ratio (molar ratio): 49/51)
Ester obtained from base oil 6: 4-cyclohexene-1,2-dicarboxylic acid and i-heptanol (ester 6: 100% by mass, cis / trans ratio (molar ratio): 35:65)
Base oil 7: ester obtained from 4-cyclohexene-1,2-dicarboxylic acid and 2-ethylhexanol (ester 7: 100% by mass, cis / trans ratio (molar ratio): 45/55)
Ester obtained from base oil 8: 4-cyclohexene-1,2-dicarboxylic acid and 3,5,5-trimethylhexanol (ester 8: 100% by mass, cis / trans ratio (molar ratio): 67/33)
Ester obtained from base oil 9: 1,2-cyclohexanedicarboxylic acid, i-butanol and n-heptanol (ester 9: 24% by mass, ester 10: 1% by mass, ester 11: 73% by mass, cis isomer / trans isomer) Ratio (molar ratio): 53/47)
Ester obtained from base oil 10: 1,2-cyclohexanedicarboxylic acid, i-butanol and 2-ethylhexanol (ester 2: 51% by mass, ester 9: 36% by mass, ester 12: 13% by mass, cis isomer / trans) Body ratio (molar ratio): 37/63)
Ester obtained from base oil 11: 1,2-cyclohexanedicarboxylic acid, i-butanol and 3,5,5-trimethylhexanol (ester 3: 27% by mass, ester 9: 18% by mass, ester 13: 55% by mass, cis body / trans body ratio (molar ratio): 62/38)
Ester obtained from base oil 12: 1,2-cyclohexanedicarboxylic acid, n-butanol and i-decanol (ester 5: 36% by mass, ester 14: 19% by mass, ester 15: 45% by mass, cis isomer / trans isomer) Ratio (molar ratio): 46/56)
Base oil 13: 4-cyclohexene-1,2-dicarboxylic acid, ester obtained from i-butanol and n-heptanol (ester 16: 25% by mass, ester 17: 2% by mass, ester 18: 73% by mass, cis isomer) / Trans body ratio (molar ratio): 56/44)
Base oil 14: ester obtained from 4-cyclohexene-1,2-dicarboxylic acid, i-butanol and 2-ethylhexanol (ester 7: 51% by mass, ester 16: 39% by mass, ester 19: 10% by mass, cis Body / trans body ratio (molar ratio): 37/63)
Ester obtained from base oil 15: 4-cyclohexene-1,2-dicarboxylic acid, i-butanol and 3,5,5-trimethylhexanol (ester 8: 26% by mass, ester 16: 17% by mass, ester 20:57 (Mass%, cis isomer / trans isomer ratio (molar ratio): 42/58)
Ester obtained from base oil 16: 4-cyclohexene-1,2-dicarboxylic acid, n-butanol and i-decanol (ester 21: 22% by mass, ester 22: 46% by mass, ester 23: 32% by mass, cis form) / Trans body ratio: 40/60)
Base oil 17: ester composed of 1,2-cyclohexanedicarboxylic acid and i-heptanol (ester 1: 100% by mass, cis / trans ratio (molar ratio): 90/10)
Base oil 18: ester composed of 1,2-cyclohexanedicarboxylic acid and i-heptanol (ester 1: 100% by mass, cis / trans ratio (molar ratio): 10/90)
Base oil 19: ester composed of 1,2-cyclohexanedicarboxylic acid and 2-ethylhexanol (ester 2: 100% by mass, cis / trans ratio (molar ratio): 90/10)
Base oil 20: ester composed of 1,2-cyclohexanedicarboxylic acid and 2-ethylhexanol (ester 2: 100% by mass, cis / trans ratio (molar ratio): 10/90)
Base oil 21: ester comprising 1,2-cyclohexanedicarboxylic acid and 3,5,5-trimethylhexanol (ester 3: 100% by mass, cis / trans ratio (molar ratio): 90/10)
Base oil 22: ester composed of 1,2-cyclohexanedicarboxylic acid and 3,5,5-trimethylhexanol (ester 3: 100% by mass, cis / trans ratio (molar ratio): 10/90)
Base oil 23: ester comprising 1,2-cyclohexanedicarboxylic acid and i-nonanol (ester 4: 100% by mass, cis / trans ratio (molar ratio): 90/10)
Base oil 24: ester composed of 1,2-cyclohexanedicarboxylic acid and i-nonanol (ester 4: 100% by mass, cis / trans ratio (molar ratio): 10/90)
Base oil 25: ester composed of 1,2-cyclohexanedicarboxylic acid and i-decanol (ester 5: 100% by mass, cis / trans ratio (molar ratio): 90/10)
Base oil 26: ester composed of 1,2-cyclohexanedicarboxylic acid and i-decanol (ester 5: 100% by mass, cis / trans ratio (molar ratio): 10/90)
Base oil 27: ester composed of 4-cyclohexene-1,2-dicarboxylic acid and i-heptanol (ester 6: 100% by mass, cis / trans ratio (molar ratio): 90/10)
Base oil 28: ester composed of 4-cyclohexene-1,2-dicarboxylic acid and i-heptanol (ester 6: 100% by mass, cis / trans ratio (molar ratio): 10/90)
Base oil 29: ester composed of 4-cyclohexene-1,2-dicarboxylic acid and 2-ethylhexanol (ester 7: 100% by mass, cis / trans ratio (molar ratio): 90/10)
Base oil 30: ester composed of 4-cyclohexene-1,2-dicarboxylic acid and 2-ethylhexanol (ester 7: 100% by mass, cis / trans ratio (molar ratio): 10/90)
Base oil 31: ester consisting of 4-cyclohexene-1,2-dicarboxylic acid and 3,5,5-trimethylhexanol (ester 8: 100% by mass, cis / trans ratio (molar ratio): 90/10)
Base oil 32: ester composed of 4-cyclohexene-1,2-dicarboxylic acid and 3,5,5-trimethylhexanol (ester 8: 100% by mass, cis / trans ratio (molar ratio): 10/90)
Base oil 33: 1, ester composed of 1,2-cyclohexanedicarboxylic acid, i-butanol and n-heptanol (ester 9: 25% by mass, ester 10: 2% by mass, ester 11: 73% by mass, cis isomer / trans isomer ratio) (Molar ratio): 90/10)
Base oil 34: ester composed of 1,2-cyclohexanedicarboxylic acid, i-butanol and n-heptanol (ester 9: 24% by mass, ester 10: 2% by mass, ester 11: 72% by mass, cis isomer / trans isomer ratio) (Molar ratio): 10/90)
Base oil 35: 1,2-cyclohexanedicarboxylic acid, ester consisting of i-butanol and 2-ethylhexanol (ester 2: 50% by mass, ester 9: 38% by mass, ester 12: 12% by mass, cis isomer / trans isomer) Ratio (molar ratio): 90/10)
Base oil 36: 1, ester obtained from 1,2-cyclohexanedicarboxylic acid, i-butanol and 2-ethylhexanol (ester 2: 51% by mass, ester 9: 38% by mass, ester 12: 11% by mass, cis isomer / trans) Body ratio (molar ratio): 10/90)
Base oil 37: 1, ester obtained from 1,2-cyclohexanedicarboxylic acid, i-butanol and 3,5,5-trimethylhexanol (ester 3: 26% by mass, ester 9: 18% by mass, ester 13: 56% by mass, cis body / trans body ratio (molar ratio): 90/10)
Base oil 38: 1, ester obtained from 1,2-cyclohexanedicarboxylic acid, i-butanol and 3,5,5-trimethylhexanol (ester 3: 27% by mass, ester 9: 16% by mass, ester 13: 57% by mass, cis body / trans body ratio (molar ratio): 10/90)
Base oil 39: 1, ester obtained from 1,2-cyclohexanedicarboxylic acid, n-butanol and i-decanol (ester 5: 33% by mass, ester 14: 20% by mass, ester 15: 47% by mass, cis isomer / trans isomer) Ratio (molar ratio): 90/10)
Base oil 40: 1, ester obtained from 1,2-cyclohexanedicarboxylic acid, n-butanol and i-decanol (ester 5: 34% by mass, ester 14: 20% by mass, ester 15: 46% by mass, cis isomer / trans isomer) Ratio (molar ratio): 10/90)
Base oil 41: 4-cyclohexene-1,2-dicarboxylic acid, ester obtained from i-butanol and n-heptanol (ester 16: 26% by mass, ester 17: 2% by mass, ester 18: 72% by mass, cis isomer) / Trans body ratio (molar ratio): 90/10)
Base oil 42: ester obtained from 4-cyclohexene-1,2-dicarboxylic acid, i-butanol and n-heptanol (ester 16: 27% by mass, ester 17: 2% by mass, ester 18: 71% by mass, cis isomer) / Trans body ratio (molar ratio): 10/90)
Base oil 43: ester obtained from 4-cyclohexene-1,2-dicarboxylic acid, i-butanol and 2-ethylhexanol (ester 7: 52% by mass, ester 16: 40% by mass, ester 19: 8% by mass, cis Body / trans body ratio (molar ratio): 90/10)
Base oil 44: ester obtained from 4-cyclohexene-1,2-dicarboxylic acid, i-butanol and 2-ethylhexanol (ester 7: 50% by mass, ester 16: 41% by mass, ester 19: 9% by mass, cis Body / trans body ratio (molar ratio): 10/90)
Base oil 45: 4-cyclohexene-1,2-dicarboxylic acid, ester obtained from i-butanol and 3,5,5-trimethylhexanol (ester 8: 26% by mass, ester 16: 18% by mass, ester 20:56 (Mass%, cis body / trans body ratio (molar ratio): 90/10)
Base oil 46: Esters obtained from 4-cyclohexene-1,2-dicarboxylic acid, i-butanol and 3,5,5-trimethylhexanol (esters 8: 27% by mass, esters 16: 17% by mass, esters 20:56) (Mass%, cis body / trans body ratio (molar ratio): 10/90)
Base oil 47: ester obtained from 4-cyclohexene-1,2-dicarboxylic acid, n-butanol and i-decanol (ester 21: 20% by mass, ester 22: 47% by mass, ester 23: 33% by mass, cis isomer) / Trans body ratio (molar ratio): 90/10)
Base oil 48: ester obtained from 4-cyclohexene-1,2-dicarboxylic acid, n-butanol and i-decanol (ester 21: 21% by mass, ester 22: 46% by mass, ester 23: 33% by mass, cis form) / Trans body ratio (molar ratio): 10/90).
Base oil 49: ester base oil of n-heptanoic acid and pentaerythritol 50: mixed fatty acid of n-pentanoic acid, n-heptanoic acid and 3,5,5-trimethylhexanoic acid (mixing ratio (molar ratio): 45 / 10/45) and pentaerythritol ester base oil 51: naphthenic mineral oil base oil 52: polypropylene glycol monomethyl ether.

The 1,2-cyclohexanedicarboxylic acid esters in the above base oils 1 to 5, 9 to 12, 17 to 26, and 33 to 40 are represented by the following general formula (2):


The R ⁴ and R ⁵ in each ester are as follows.

Ester 1 R ⁴ : i-heptyl group, R ⁵ : i-heptyl group ester 2 R ⁴ : 2-ethylhexyl group, R ⁵ : 2-ethylhexyl group ester 3 R ⁴ : 3,5,5-trimethylhexyl group , ^R 5: 3,5,5-trimethyl-hexyl ester 4 ^R 4: i-nonyl ^group, R 5: i-nonyl ester 5 ^R 4: i-decyl ^group, R 5: i-decyl ester 9 R ^4: i-butyl ^group, R 5: i-butyl group ester 10 ^R 4: i-butyl ^group, R 5: heptyl group ester 11 to n- ^R 4: n- ^heptyl, R 5: the n- heptyl Group ester 12 R ⁴ : i-butyl group, R ⁵ : 2-ethylhexyl group ester 13 R ⁴ : i-butyl group, R ⁵ : 3,5,5-trimethylhexyl group ester 14 R ⁴ : n-butyl group, R ^5: n- butyl Group ester 15 R ⁴ : n-butyl group, R ⁵ : i-decyl group.

The 4-cyclohexene-1,2-dicarboxylic acid ester in the above base oils 6-8, 13-16, 27-32, 41-48 is represented by the following general formula (3):


The R ⁶ and R ⁷ in each ester are as follows.
Ester 6 R ⁶ : i-heptyl group, R ⁷ : i-heptyl group ester 7 R ⁶ : 2-ethylhexyl group, R ⁷ : 2-ethylhexyl group ester 8 R ⁶ : 3,5,5-trimethylhexyl group , R7: 3,5,5-trimethylhexyl group ester 16 R ⁶ : i-butyl group, R ⁷ : i-butyl group ester 17 R ⁶ : i-butyl group, R ⁷ : n-heptyl group ester 18 R ^6: n- ^heptyl, R 7: the n- heptyl ester 19 ^R 6: i-butyl ^group, R 7: 2-ethylhexyl group ester 20 ^R 6: i-butyl ^group, R 7: ^3,5, 5-trimethylhexyl group ester 21 R ⁶ : n-butyl group, R ⁷ : n-butyl group ester 22 R ⁶ : n-butyl group, R ⁷ : i-decyl group ester 23 R ⁶ : i-decyl group, R ^7: i- Sill group.

  Next, the following evaluation tests were carried out for each of the refrigerating machine oils of Examples 1-48 and Comparative Examples 1-4.

(Evaluation of refrigerant compatibility 1)
In accordance with JIS-K-2211 “Refrigerating machine oil” “Compatibility test method with refrigerant”, a mixed refrigerant (mixing ratio (mass ratio) of 2,3,3,3-tetrafluoropropene and trifluoroiodomethane. Ratio): 2,3,3,3-tetrafluoropropene / trichloroiodomethane = 70/30) 2 g of refrigerating machine oil is blended with 18 g, and the refrigerant and refrigerating machine oil dissolve at 0 ° C. Observed. The obtained results are shown in Tables 1-11. In Tables 1 to 11, “compatible” means that the refrigerant and the refrigerating machine oil are dissolved in each other, and “separation” means that the refrigerant and the refrigerating machine oil are separated into two layers.

(Evaluation of refrigerant compatibility 2)
In accordance with JIS-K-2211 “Refrigerating machine oil” “Compatibility testing method with refrigerant”, 2 g of refrigerating machine oil is blended with 18 g of 2,3,3,3-tetrafluoropropene, and the refrigerant and refrigerating machine oil are mixed. Were observed to be mutually dissolved at 0 ° C. The obtained results are shown in Tables 1-11. In Tables 1 to 3, “compatible” means that the refrigerant and the refrigerating machine oil are dissolved in each other, and “separation” means that the refrigerant and the refrigerating machine oil are separated into two layers.

(Evaluation of thermal and chemical stability 1)
1 g of refrigerating machine oil composition (initial hue L0.5) adjusted to a water content of 10 ppm or less in accordance with JIS-K-2211, and a mixture of 2,3,3,3-tetrafluoropropene and trifluoroiodomethane 1 g of refrigerant (mixing ratio (mass ratio): 2,3,3,3-tetrafluoropropene / trichloroiodomethane = 70/30) and catalyst (each wire of iron, copper, and aluminum) in a glass tube After encapsulating, it was heated to 150 ° C. and held for 1 week for testing. After the test, the hue of the refrigerator oil composition and the color change of the catalyst were evaluated. Hue was evaluated according to ASTM D156. Further, the color change of the catalyst was visually observed for the appearance, and it was evaluated whether it corresponded to no change, no gloss, or blackening. The obtained results are shown in Tables 1 to 11.

(Evaluation of thermal and chemical stability 2)
In accordance with JIS-K-2211, 1 g of refrigerating machine oil (initial hue L0.5) adjusted to a water content of 10 ppm or less, 1 g of 2,3,3,3-tetrafluoropropene, and catalyst (iron, copper, aluminum) Each wire) was sealed in a glass tube, heated to 150 ° C. and held for 1 week for testing. After the test, the hue of the refrigerator oil composition and the color change of the catalyst were evaluated. Hue was evaluated according to ASTM D156. Further, the color change of the catalyst was visually observed for the appearance, and it was evaluated whether it corresponded to no change, no gloss, or blackening. The obtained results are shown in Tables 1 to 11.

  As is clear from the results shown in Tables 1 to 11, the refrigerating machine oils of Examples 1 to 48 were used with a fluoropropene refrigerant and / or a trifluoroiodomethane refrigerant. It can be seen that the stability is excellent.

Claims (5)

An alicyclic ring and the following general formula (1):
-COOR ¹ (1)
(Wherein R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms)
And two alicyclic dicarboxylic acid esters in which two of the ester groups are bonded to adjacent carbon atoms on the alicyclic ring, and the following compounds (a) to ( c):
(A) An alicyclic polyvalent carboxylic acid having an alicyclic ring and two or more carboxyl groups, wherein at least two of the carboxyl groups are bonded to adjacent carbon atoms on the alicyclic ring. Or a derivative thereof,
(B) a compound having two or more hydroxyl groups or a derivative thereof, and (c) a compound having one hydroxyl group or a derivative thereof,
At least one alicyclic polycarboxylic acid ester selected from the group consisting of alicyclic polycarboxylic acid esters obtained using
A fluoropropene refrigerant and / or a trifluoroiodomethane refrigerant;
A working fluid composition for a refrigerator, comprising:   Examples of the fluoropropene refrigerant include 1,3,3,3-tetrafluoropropene (HFO-1234ze), 2,3,3,3-tetrafluoropropene (HFO-1234yf), and 1,2,3,3,- The working fluid composition for a refrigerator according to claim 1, comprising at least one selected from tetrafluoropropene (HFO-1225ye). At least one fluoropropene refrigerant;
It contains at least one selected from saturated hydrofluorocarbons, hydrocarbons having 3 to 5 carbon atoms, dimethyl ether, carbon dioxide, bis (trifluoromethyl) sulfide, and trifluoroiodomethane refrigerant, Item 3. A working fluid composition for a refrigerator according to Item 1 or 2. The fluoropropene refrigerant is 1,2,3,3,3-pentafluoropropene, 1,3,3,3-tetrafluoropropene, 2,3,3,3-tetrafluoropropene, 1,2,3, At least one selected from 3-tetrafluoropropene and 3,3,3-trifluoropropene,
The saturated hydrofluorocarbon refrigerant is difluoromethane, pentafluoroethane, 1,1,2,2-tetrafluoroethane, 1,1,1,2-tetrafluoroethane, 1,1-difluoroethane, fluoroethane, 1,1 1,1,2,3,3,3-heptafluoropropane, 1,1,1,2,3,3-hexafluoropropane, 1,1,1,3,3,3-hexafluoropropane, 1,1 , 1,3,3-pentafluoropropane and 1,1,1,3,3-pentafluorobutane,
The working fluid for a refrigerator according to claim 3, wherein the hydrocarbon refrigerant having 3 to 5 carbon atoms is at least one selected from propane, normal butane, isobutane, 2-methylbutane, and normal pentane. Composition. An alicyclic ring and the following general formula (1):
-COOR ¹ (1)
(Wherein R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms)
And two alicyclic dicarboxylic acid esters in which two of the ester groups are bonded to adjacent carbon atoms on the alicyclic ring, and the following compounds (a) to ( c):
(A) An alicyclic polyvalent carboxylic acid having an alicyclic ring and two or more carboxyl groups, wherein at least two of the carboxyl groups are bonded to adjacent carbon atoms on the alicyclic ring. Or a derivative thereof; (b) a compound having two or more hydroxyl groups or a derivative thereof; and (c) a compound having one hydroxyl group or a derivative thereof; A refrigerating machine oil containing at least one selected alicyclic polyvalent carboxylic acid ester and used together with a fluoropropene refrigerant and / or a trifluoroiodomethane refrigerant.