JPH069977A - Refrigerator working fluid composition - Google Patents

Abstract

(57) [Summary] (Modified) [Structure] An ester obtained from a specific aliphatic polyhydric alcohol and a saturated aliphatic monocarboxylic acid or a derivative thereof,
An ester obtained from a specific aliphatic polyhydric alcohol, a saturated aliphatic monocarboxylic acid or a derivative thereof and a saturated aliphatic dicarboxylic acid or a derivative thereof, a specific aliphatic polyhydric alcohol, and a saturated aliphatic monohydric alcohol, A refrigerating machine oil comprising, as a base oil, one or more synthetic oils selected from the group consisting of an ester obtained from a polyvalent carboxylic acid or a derivative thereof and a carbonate represented by the formula (I). Content of compound with melting point of 10 ℃ or higher is 500
A composition for a refrigerating machine working fluid, which contains a refrigerating machine oil and hydrofluorocarbon in an amount of ppm or less. (In the formula, R ¹ and R ³ represent an alkyl group or an aryl group having 1 to 18 carbon atoms. R ² is an alkylene group or an arylene group having 2 to 8 carbon atoms, and m and n are 0 to 100. The effect is a composition which is excellent in compatibility with hydrofluorocarbons, electric insulation, and hygroscopicity, and in which the capillary tube is particularly unlikely to be clogged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working fluid composition for refrigerators, and more particularly to a working fluid composition for compression refrigerators for electric refrigerators, room air conditioners and the like.

[0002]

2. Description of the Related Art Recently, the problems to be solved by the invention
The use of dichlorodifluoromethane (CFC12), which is used in refrigerators and car coolers to protect the ozone layer, has been regulated, and it has been decided that it will be prohibited in the future. Further, subsequently, the use of chlorodifluoromethane (HCFC22) used for room air conditioners and the like is about to be regulated. Therefore, this CFC12 and HCFC22
As an alternative to hydrofluorocarbons that do not destroy the ozone layer, such as 1,1,1,2-tetrafluoroethane (HFC134a) and difluoromethane (HFC)
32) has been developed. However, since hydrofluorocarbons have a higher polarity than CFC12 and HCFC22, if a lubricating oil such as naphthene-based mineral oil, poly α-olefin, or alkynebenzene that has been generally used as a refrigerating machine oil is used, it becomes Poor compatibility with hydrofluorocarbons, causing two-layer separation at low temperatures. When two-layer separation occurs, oil return deteriorates, a thick oil film adheres to the vicinity of the condenser or evaporator as a heat exchanger to hinder heat transfer, and it is important that lubrication failure and foaming at startup occur. Cause defects. Therefore, the conventional refrigerating machine oil cannot be used as the refrigerating machine oil under these new refrigerant atmospheres.

Also, regarding lubricity, CFC12 and HC
In FC22, there was an effect that it partially decomposed to generate hydrogen chloride, and this hydrogen chloride reacted with the friction surface to form a chloride film to improve lubricity. However, since such effects cannot be expected for hydrofluorocarbons containing no chlorine atom, a refrigerating machine oil used together with hydrofluorocarbons is required to have a lubricating oil superior to the conventional one. Further, the refrigerating machine oil used together with the hydrofluorocarbon must have good thermal stability in the coexistence with the hydrofluorocarbon. In addition, in addition to this, in compression refrigerators of electric refrigerators, there are organic materials used for motors such as insulating materials and enameled wires, so as a working fluid consisting of hydrofluorocarbon and refrigerator oil, these organic materials are used. It is necessary that the material is not adversely affected and that the electrical insulation is good. As a refrigerating machine oil that can be used together with a hydrofluorocarbon, for example, 1,1,1,2-tetrafluoroethane (HFC134a), US Pat. No. 4,755,316 (Japanese Patent Laid-Open No. 2-502)
No. 385), specification, JP-A-1-198694, JP-A-1
-256594 discloses a polyether compound.

Since the polyether compound is more polar than the naphthenic mineral oil, the compatibility with HFC134a at low temperature is certainly good. However, US Pat.
As described in the specification of 5,316, the polyether compound has a problem that it causes two-layer separation when the temperature rises, and therefore cannot be used as a refrigerating machine oil without anxiety. Further, the polyether compound has some other problems. One is that it has poor electrical insulation. This is a very big problem and cannot be used in refrigerators for electric refrigerators. Another problem is that it is highly hygroscopic. Due to the water content in the polyether compound, the thermal stability in the coexistence with HFC134a is deteriorated, or the PET film or the like which is an organic material is hydrolyzed.

Ester compounds and carbonate compounds have been developed in order to improve the problems of the polyether compounds such as the electric insulating property and the hygroscopic property. For example,
As a refrigerating machine oil that can be used together with 1,1,1,2-tetrafluoroethane (HFC134a), US Pat.
851,144 (JP-A-2-276894) and JP-A-2-569
Japanese Patent Publication No. 3,216,541 discloses a mixed oil of polyether oil and ester oil, and U.S. Pat.
1,179, European Patents 445,610 and 445,61
No. 1 specification, International Patent Publication No. 90/12849 (Japanese Patent Publication No. 3-505602)
No.), WO 91/09097, JP 3-24197 A, JP 3-88892 A, JP 3-128991 A, JP 3-128992 A.
JP-A-3-179091, JP-A-3-200895, JP-A-3-20
0896, JP 3-217494 A, JP 3-217498 A, JP
3-227397, JP 3-243697, JP 3-252497, JP 3-275799, JP 3-285992, JP 4-4294,
JP 4-20597 A, JP 4-25595 A, JP 4-28792 A
JP, 4-72390, 4-85396, 4-88
Ester oils are disclosed in, for example, 096 and JP-A-4-91194. Also, European Patents 452,816 and 421,298.
And 426,153, JP-A-2-132178, JP-A-3-
Carbonate oil is disclosed in Japanese Patent No. 217495, Japanese Patent Laid-Open No. 3-247695 and the like.

These ester compounds and carbonate compounds are excellent in compatibility with hydrofluorocarbons and are also excellent in thermal stability in the presence of hydrofluorocarbons. In addition, it has extremely excellent electrical insulation properties and considerably low hygroscopicity as compared with polyether compounds.
However, when a refrigerator is operated using these proposed refrigerating machine oils, the compound adheres to the discharge port, the dryer, the capillary tube, etc., and in some cases, the capillary tube is clogged.

[0007] Therefore, the fact is that there is a demand in the art for the development of refrigerating machine oil in which the capillary tube is not clogged. The purpose of the present invention is to include a specific refrigerating machine oil, which has excellent compatibility with hydrofluorocarbons, electric insulation, and excellent hygroscopicity, and is particularly useful for a refrigerating machine working fluid in which the capillary tube is less likely to be clogged than conventional ones. To provide a composition.

[0008]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventor has found that certain compounds can achieve the above object, and completed the present invention. I arrived. That is, the present invention includes: A) (a) an aliphatic polyhydric alcohol having 1 to 6 primary hydroxy groups, and (b) a linear or branched saturated aliphatic monocarboxylic acid having 2 to 9 carbon atoms, or Ester obtained from the derivative B) (a) an aliphatic polyhydric alcohol having 1 to 6 primary hydroxy groups, and (b) a linear or branched saturated aliphatic monocarboxylic acid having 2 to 9 carbon atoms, or Its derivative and (c)
An ester obtained from a linear or branched saturated aliphatic dicarboxylic acid having 2 to 10 carbon atoms or a derivative thereof C) (a) an aliphatic polyhydric alcohol having 1 to 6 primary hydroxy groups, and (d) An ester obtained from a straight-chain or branched-chain saturated aliphatic monohydric alcohol having 1 to 10 carbon atoms and (e) a polyvalent carboxylic acid having 2 to 10 carbon atoms or a derivative thereof, and D) represented by the formula (I) Carbonate represented

[Chemical 3] (In the formula, R ¹ and R ³ are alkyl groups having 1 to 18 carbon atoms, aryl groups, alkylaryl groups, aralkyl groups,
Alternatively, it represents a group represented by — (R ⁵ O) k—R ⁴ .
However, R ⁴ is an alkyl group having 1 to 18 carbon atoms, an aryl group, an alkylaryl group or an aralkyl group, R ⁵ is an alkylene group having 2 to 18 carbon atoms, an arylene group, an alkylarylene group or an aralkylene group, and k is 1-100
And the k R ⁵ O may be the same or different. R ² is an alkylene group having 2 to 18 carbon atoms, an arylene group, an alkylarylene group or an aralkylene group, m is an integer of 0 to 100, n is an integer of 0 to 100, and m R ² O are the same. May or may not be different, and n

[Chemical 4] May be the same or different. (4) A refrigerating machine oil comprising one or more synthetic oils selected from the group consisting of the following) as a base oil, wherein the refrigerating machine oil has a melting point of 10 ° C. or higher and a compound content of 500 ppm or lower, and hydrofluorocarbons. The present invention provides a composition for a working fluid of a refrigerator containing the composition.

The composition for a working fluid for a refrigerator of the present invention contains a refrigerating machine oil containing an ester and / or a carbonate as a base oil, and the aliphatic polyhydric alcohol of the component (a) used for obtaining the ester is used. Of the hydroxy groups,
1 to 6 are primary hydroxy groups, specifically, neopentyl glycol, 2-ethyl-2-methyl-1,3-propanediol, 2-isopropyl-2
-Methyl-1,3-propanediol, 2,2-diethyl-
Hindered substances such as 1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, trimethylolethane, trimethylolpropane, trimethylolnonane, pentaerythritol, ditrimethylolpropane and dipentaerythritol. Alcohol or ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,2-
Propanediol, 2-methyl-1,3-propanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 3,3-dimethyl-1,2-
Butanediol, 1,7-heptanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol,
1,8-octanediol, 2,2,4-trimethyl-1,3-
Pentanediol, 1,9-nonanediol, 1,2-decanediol, 1,10-decanediol, glycerin, diglycerin, triglycerin, tetraglycerin, polyglycerin, 1,2,4-butanetriol, 1,2 And polyhydric alcohols such as 1,6-hexanetriol, 1,2,3,4-butanetetrol, sorbitol and mannitol. The number of carbon atoms of these aliphatic polyhydric alcohols is 2 to
30, preferably 2 to 20, more preferably 2 to 10. When the number of carbon atoms is more than 30, the viscosity becomes high,
The compatibility with the hydrofluorocarbon-based refrigerant also deteriorates. Moreover, the number of hydroxy groups of these aliphatic polyhydric alcohols is 2 to 6, preferably 2 to 4, and more preferably 2 to 3. If there are more than 6 hydroxy groups, the viscosity becomes too high. From the viewpoint of heat resistance,
Hindered alcohol is particularly good.

The saturated aliphatic monocarboxylic acid as the component (b) has 2 to 9 carbon atoms, and more preferably 5 to 9 carbon atoms. When the number of carbon atoms is more than 9, the compatibility with the hydrofluorocarbon-based refrigerant becomes poor. If the number of carbon atoms is smaller than 2, corrosiveness to metals may increase. Specific examples of these monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, 2-methylbutyric acid, caproic acid, 2-methylvaleric acid, 3-methylvaleric acid, 4-methylvaleric acid, 2,2-dimethylbutyric acid, 2-ethylbutyric acid, tert-butylacetic acid, cyclopentanecarboxylic acid, enanthic acid, 2,2-dimethylpentanoic acid, 2-ethylpentanoic acid, 3-ethylpentanoic acid , 2
-Methylhexanoic acid, 3-methylhexanoic acid, 4-methylhexanoic acid, 5-methylhexanoic acid, cyclohexanecarboxylic acid, cyclopentyl acetic acid, caprylic acid, 2-ethylhexanoic acid, 3,5-dimethylhexanoic acid, 2,2 -Dimethylhexanoic acid, 2-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, 2-propylpentanoic acid, 3,4-dimethylhexanoic acid, cyclohexylacetic acid, 3-cyclopentylpropionic acid, pelargonic acid,
2,2-dimethylheptanoic acid, 3,5,5-trimethylhexanoic acid, 2-methyloctanoic acid, 2-ethylheptanoic acid,
Examples thereof include 3-methyloctanoic acid, 2-ethyl-2,3,3-trimethylbutyric acid, 2,2,4,4-tetramethylpentanoic acid, and 2,2-diisopropylpropionic acid. Examples of monocarboxylic acid derivatives include lower alkyl esters such as methyl ester and ethyl ester, acid anhydrides and the like. A branched chain saturated aliphatic monocarboxylic acid is preferable to a linear saturated aliphatic monocarboxylic acid from the viewpoint of compatibility with a hydrofluorocarbon-based refrigerant and hydrolysis resistance. Further, those having an unsaturated bond are not preferable in terms of heat resistance.

The saturated fatty acid dicarboxylic acid as the component (c) is
Having 2 to 10 carbon atoms, having 1 carbon atom
When it is more than 0, the compatibility with the hydrofluorocarbon type refrigerant becomes poor. Specific examples of these dicarboxylic acids or their derivatives include oxalic acid, malonic acid, methylmalonic acid, succinic acid, ethylmalonic acid, dimethylmalonic acid, methylsuccinic acid, glutaric acid, adipic acid, and 2,2-dimethylsuccinic acid. 2,3-dimethylsuccinic acid, 2-methylglutaric acid, 3-methylglutaric acid, butylmalonic acid, diethylmalonic acid, 2,2-dimethylglutaric acid, 2,4-dimethylglutaric acid, 3,3-dimethyl Glutaric acid, 2-ethyl-2-methylsuccinic acid, 3-methyladipic acid, pimelic acid, suberic acid, 2,2-dimethyladipic acid, azelaic acid, sebacic acid, or their lower alkyls such as methyl ester and ethyl ester. Examples thereof include esters and acid anhydrides.

The saturated aliphatic monohydric alcohol as the component (d) has 1 to 10 carbon atoms, and more preferably 5 to 9 carbon atoms. When the number of carbon atoms is more than 10, the compatibility with the hydrofluorocarbon type refrigerant becomes poor. Specific examples of these monohydric alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 1-pen. Tanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-
Methyl-2-butanol, 2-methyl-2-butanol, 2,2-dimethyl-1-propanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2-methyl-1-pentanol, 2 -Methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-
Pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 2,3-dimethyl-1-butanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol,
3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2,2-dimethylbutanol, cyclohexanol, cyclopentylmethanol, methylcyclopentanol, 1-heptanol, 2-heptanol, 3-heptanol, 2- Methyl-1-hexanol, 2-methyl-2-hexanol, 2-methyl-3-hexanol, 5-methyl-2-hexanol, 3-ethyl-3-
Pentanol, 2,2-dimethyl-3-pentanol, 2,
3-dimethyl-3-pentanol, 2,4-dimethyl-3
-Pentanol, 4,4-dimethyl-2-pentanol,
3-methyl-1-hexanol, 4-methyl-1-hexanol, 5-methyl-1-hexanol, 2-ethylpentanol, cycloheptanol, cyclohexylmethanol, methylcyclohexanol, 1-octanol, 2-octanol, 3 -Octanol, 4-methyl-3-heptanol, 6-methyl-2-heptanol,
2-ethyl-1-hexanol, 2-propyl-1-pentanol, 2,4,4-trimethyl-1-pentanol,
3,5-dimethyl-1-hexanol, 2-methyl-1-
Heptanol, 2,2-dimethyl-1-hexanol, cyclooctanol, 1-cyclohexylethanol, 2
-Cyclohexyl ethanol, dimethyl cyclohexanol, ethyl cyclohexanol, 1-nonanol, 2
-Nonanol, 3,5,5-trimethyl-1-hexanol, 2,6-dimethyl-4-heptanol, 3-ethyl-
2,2-Dimethyl-3-pentanol, 3-cyclohexylpropanol, 5-methyloctanol, 1-decanol, 2-decanol, 4-decanol, 3,7-dimethyl-1-octanol, 2,4,6-trimethyl Heptanol, 4-cyclohexylbutanol, butylcyclohexanol, 3,3,5,5-tetramethylcyclohexanol and the like can be mentioned.

The polyvalent carboxylic acid as the component (e) has 2 to 10 carbon atoms, and if it has more than 10 carbon atoms, the compatibility with the hydrofluorocarbon type refrigerant becomes poor. Specific examples of these polyvalent carboxylic acids or derivatives thereof include saturated aliphatic dicarboxylic acids of component (c), 1,2,
Linear or branched saturated aliphatic polycarboxylic acids such as 3-tricarboxypropane, β-methyltricarboxylic acid, 1,3,6-tricarboxyhexane, phthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid Examples thereof include aromatic polycarboxylic acids such as acids, lower alkyl esters such as methyl esters and ethyl esters thereof, acid anhydrides and the like.

The compatibility of the ester of the present invention with a hydrofluorocarbon type refrigerant at low temperature generally becomes worse as the viscosity becomes higher. Therefore, an ester which is preferable in terms of compatibility has a kinematic viscosity at 100 ° C. of 1 cst or more 10
0 cst or less, more preferably 1 cst or more 3
It is 0 cst or less. From the viewpoint of compatibility with hydrofluorocarbon-based refrigerants, the saponification value of the ester of the present invention is preferably 250 mgKOH / g or more, more preferably 280 mgKOH / g or more in the ester of A). In the ester of B) and C), 330 mgKOH / g or more is preferable, and 350 mgKOH / g or more is more preferable.

The ester according to the present invention is (a) a polyhydric alcohol which is a raw material of the ester, (b) an aliphatic monocarboxylic acid or a derivative thereof, and (c) which are raw materials of the ester, from the viewpoints of corrosion resistance to metals and hydrolysis stability. The aliphatic dicarboxylic acid or its derivative, the (d) monohydric alcohol, and the (e) polyhydric carboxylic acid or its derivative preferably have a branched structure, and all of the alcohol moiety and the carboxylic acid moiety have a branched structure. If there is, it is particularly preferable.

Among the esters of A) used in the present invention, neopentyl glycol, 2-ethyl-2-methyl-1,3-propanediol, 2-isopropyl-2-methyl-1,3-propanediol, 2,2-diethyl-1,3
-Propanediol, 2-n-butyl-2-ethyl-1,3
-Hindered alcohols such as propanediol, trimethylolethane, trimethylolpropane, trimethylolnonane, pentaerythritol and dipentaerythritol, and saturated branched chain aliphatic monocarboxylic acids having 7 to 9 carbon atoms, among which, 2-methyl At least one carboxylic acid selected from the group consisting of hexanoic acid, 3-methylhexanoic acid, 5-methylhexanoic acid, 2-ethylhexanoic acid, 3,5-dimethylhexanoic acid, and 3,5,5-trimethylhexanoic acid. The ester obtained from the acid is excellent in compatibility with the hydrofluorocarbon type refrigerant, hydrolysis resistance, and thermal stability.

Specifically, neopentyl glycol di-2
-Methyl hexanate, trimethylolpropane tri 2
-Methyl hexanate, pentaerythritol tetra 2
-Methyl hexanate, neopentyl glycol di 3,5,
5-trimethylhexanate, trimethylolpropane tri 3,5,5-trimethylhexanate, neopentyl glycol di-2-ethylhexanate, trimethylolpropane tri-2-ethylhexanate, pentaerythritol tetra 3,5-dimethyl Hexanate, 2-methylhexanoic acid / 3,5,5-trimethylhexanoic acid = about 35/6
An ester obtained by reacting 5% by weight of a mixed carboxylic acid with trimethylolpropane, 2-methylhexanoic acid /
3,5-Dimethylhexanoic acid = ester obtained by reacting mixed carboxylic acid of about 80/20 weight ratio with pentaerythritol, 2-methylhexanoic acid / 3,5,5-trimethylhexanoic acid = about 90/10 weight Ester obtained by reacting a mixed carboxylic acid with pentaerythritol in a ratio of 2-methylhexanoic acid / 2-ethylhexanoic acid = about 60/40 (weight ratio) and obtained by reacting pentaerythritol Ester, 3-methylhexanoic acid / 5-methylhexanoic acid = approx. 70/30 (weight ratio)
Ester obtained by reacting trimethylolpropane with mixed carboxylic acid of 3-methylhexanoic acid / 5-methylhexanoic acid / 3,5,5-trimethylhexanoic acid = about 27/13
/ 60 (weight ratio), an ester obtained by reacting trimethylolpropane with a mixed carboxylic acid, 3-methylhexanoic acid / 5-methylhexanoic acid / 3,5,5-trimethylhexanoic acid = about 60/30/10 (Weight ratio) mixed carboxylic acid and ester obtained by reacting trimethylolpropane, 3-methylhexanoic acid / 5-methylhexanoic acid / 2-ethylhexanoic acid = about 33/17/50 (weight ratio) Examples thereof include esters obtained by reacting carboxylic acid with pentaerythritol.

In the ester of B) of the present invention, (f): an aliphatic dihydric alcohol having 1 to 2 primary hydroxy groups in the component (a), and (b): carbon. A linear or branched saturated aliphatic monocarboxylic acid having 2 to 9 carbon atoms or a derivative thereof, and (g): a linear or branched saturated aliphatic dicarboxylic acid having 2 to 8 carbon atoms in the component (c) Or an ester obtained from the derivative thereof, or the ester of C) of the present invention, wherein (f): an aliphatic dihydric alcohol having 1 to 2 primary hydroxy groups in the component (a), (D): an ester obtained from a saturated aliphatic monohydric alcohol and (g): (e) component, a linear or branched saturated aliphatic dicarboxylic acid having 2 to 8 carbon atoms or a derivative thereof, Low temperature compatibility and lubricity with hydrofluorocarbon refrigerants Is especially good at

Specific examples of the component (f) include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-propanediol, 1,2-butanediol, 1, 3-butanediol, 1,4-butanediol, 2-methyl-1,2-propanediol, 2-methyl-1,3-propanediol, 1,
2-pentanediol, 1,3-pentanediol, 1,4
-Pentanediol, 1,5-pentanediol, 1,2-
Hexanediol, 1,5-hexanediol, 1,6-hexanediol, 3,3-dimethyl-1,2-butanediol, 1,7-heptanediol, 2-ethyl-1,3-hexanediol, 1, 2-octanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,9-nonanediol, 1,2-decanediol,
Examples thereof include dihydric alcohols such as 1,10-decanediol and hindered alcohols represented by the following formula (II).
Specific examples of the hindered alcohol include neopentyl glycol, 2-ethyl-2-methyl-1,3-propanediol, 2-isopropyl-2-methyl-1,3-
Examples thereof include propanediol, 2,2-diethyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol and the like. The number of carbon atoms of these aliphatic dihydric alcohols is 2 to 30, preferably 2 to 20, and more preferably 2 to 10. From the viewpoint of heat resistance, the hindered alcohol represented by the following formula (II) is particularly excellent.

[0020]

[Chemical 5]

(In the formula, R ⁶ and R ⁷ are each 1 to 1 carbon atoms.
6 represents an alkyl group. )

Specific examples of the component (g) include oxalic acid, malonic acid, methylmalonic acid, succinic acid, ethylmalonic acid, dimethylmalonic acid, methylsuccinic acid, glutaric acid, adipic acid, 2,2- Dimethylsuccinic acid, 2,3-dimethylsuccinic acid, 2-methylglutaric acid, 3-methylglutaric acid, butylmalonic acid, diethylmalonic acid, 2,2-
Dimethyl glutaric acid, 2,4-dimethyl glutaric acid, 3,3
-Dimethylglutaric acid, 2-ethyl-2-methylsuccinic acid, 3-methyladipic acid, pimelic acid, suberic acid,
2,2-Dimethyl adipic acid may be mentioned.

The compatibility obtained by using the above compounds,
As a preferred specific example of the ester having particularly excellent lubricity, 2-methylhexanoic acid / adipic acid = about 70/30
An ester obtained by reacting (weight ratio) mixed carboxylic acid and neopentyl glycol, or 2-methylhexanoic acid / adipic acid = about 72/28 (weight ratio) mixed carboxylic acid and 2,2-diethyl-1 An ester obtained by reacting 1,3-propanediol or an ester obtained by reacting a mixed carboxylic acid of 2-ethylhexanoic acid / glutaric acid = about 57/43 (weight ratio) with neopentyl glycol, or 2- An ester obtained by reacting a mixed carboxylic acid of methylhexanoic acid / glutaric acid = about 43/57 (weight ratio) with neopentyl glycol, 2-
Ester obtained by reacting mixed carboxylic acid of ethylhexanoic acid / adipic acid = about 64/36 (weight ratio) with neopentyl glycol, 3-methylhexanoic acid / 5-methylhexanoic acid / adipic acid = about 50/20 / 30 (weight ratio) mixed carboxylic acid and neopentyl glycol ester, 2-ethylhexanoic acid / adipic acid = about 25/75 (weight ratio) mixed carboxylic acid and neopentyl glycol Examples thereof include esters obtained by reacting adipic acid with a mixed alcohol of neopentyl glycol / 2-ethylhexanol = about 47/53 (weight ratio).

The ester A) used in the present invention includes at least one polyhydric alcohol of the above (a) and the above (b).
It can be obtained by a usual esterification reaction or transesterification reaction with one or more kinds of the monocarboxylic acid or lower alkyl ester thereof, an acid anhydride and the like.

The ester of B) used in the present invention includes at least one polyhydric alcohol of the above (a) and the above (b).
Of one or more kinds of monocarboxylic acid or lower alkyl ester or acid anhydride thereof and the like and one or more kinds of dicarboxylic acid or lower alkyl ester or acid anhydride or the like of the above (c) Or a transesterification reaction. At this time, the dicarboxylic acid or the derivative thereof of (c) was added to 1 mol of the polyhydric alcohol of (a).
React less than 9 moles. More preferably, it is 0.8 mol or less. If more than 0.9 mol is reacted, the viscosity increases. The number of moles of the monocarboxylic acid of (b) or its derivative relative to 1 mole of the polyhydric alcohol of (a) is the number of moles of the dicarboxylic acid or its derivative described in (c) and the hydroxyl value of the ester to be obtained. Determined by

The ester of C) used in the present invention includes at least one polyhydric alcohol of (a) above and (d) above.
1 or more of the monohydric alcohols described above and 1 of the above-mentioned polyvalent carboxylic acid (e) or its lower alkyl ester, acid anhydride, etc.
It can be obtained by a usual esterification reaction or transesterification reaction depending on the number of species. At this time, 1.5 mol or less of the polyhydric alcohol (a) is reacted with 1 mol of the polycarboxylic acid (e) or its derivative. More preferably, it is 0.9 mol or less. Viscosity increases when more than 1.5 mol is reacted. The number of moles of the monohydric alcohol of (d) to 1 mole of the polyvalent carboxylic acid or derivative thereof of (e) is
It is determined by the number of moles of the polyhydric alcohol of (a) described above and the hydroxyl value of the ester to be obtained.

The lower the acid value of the ester of A), B) and C), the more preferable, and usually 0.1 mgKOH / g or less, particularly 0.05.
It is preferably mgKOH / g or less. If the acid value is greater than 0.1 mg KOH / g, the corrosiveness to metals may increase, which is not preferable. The hydroxyl value of these esters is usually
0.1 mgKOH / g or more and 50 mgKOH / g or less, preferably 0.1 m
It is gKOH / g or more and 30 mgKOH / g or less. More preferably,
It is 0.1 mgKOH / g or more and 20 mgKOH / g or less. Hydroxyl value is 50 mg
If it is higher than KOH / g, the hygroscopicity will be high, and if it is lower than 0.1 mgKOH / g, the abrasion resistance will be poor. The carbonate used in the present invention is represented by the following formula (I).

[0028]

[Chemical 6]

(In the formula, R ¹ and R ³ have 1 to 18 carbon atoms.
Represents an alkyl group, an aryl group, an alkylaryl group, an aralkyl group, or a group represented by — (R ⁵ O) k—R ⁴ . However, R ⁴ is an alkyl group having 1 to 18 carbon atoms, an aryl group, an alkylaryl group or an aralkyl group, R ⁵ is an alkylene group having 2 to 18 carbon atoms, an arylene group, an alkylarylene group or an aralkylene group, k
Represents an integer of 1 to 100, and k R ⁵ O may be the same or different. R ² is an alkylene group having 2 to 18 carbon atoms, an arylene group, an alkylarylene group or an aralkylene group, m is an integer of 0 to 100, and n is 0 to 1
Represents an integer of 00, m R ² O may be the same or different, and n R ² O

[0030]

[Chemical 7]

May be the same or different. )

R ⁴ is an alkyl group having 1 to 18 carbon atoms,
An aryl group, an alkylaryl group or an aralkyl group. It preferably has 1 to 10 carbon atoms, and if the number of carbon atoms exceeds 18, the compatibility with hydrofluorocarbon becomes poor. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a cyclopropyl group,
Butyl group, 1-methylpropyl group, 2-methylpropyl group,
t-butyl group, pentyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylpropyl group, 1,
1-dimethylpropyl group, 1,2-dimethylpropyl group, 2,2-
Dimethylpropyl group, cyclopentyl group, hexyl group,
1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 1-ethylbutyl group, 2-
Ethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1,1-dimethylbutyl group, 2,2-dimethylbutyl group, 3,3-dimethylbutyl group , 1-
Ethyl-2-methylpropyl group, 1-ethyl-1-methylpropyl group, 1,1,2-trimethylpropyl group, 1,2,2-trimethylpropyl group, cyclohexyl group, cyclopentylmethyl group, methylcyclopentyl group, heptyl Group, 1-methylhexyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 1-ethylpentyl group, 2-ethylpentyl group, 2,4-dimethylpentyl group Group, 3,4-dimethylpentyl group, 1,1-dimethylpentyl group, 1,4-dimethylpentyl group, 1-propylbutyl group,
1-isopropylbutyl group, 1,3,3-trimethylbutyl group,
1,1-diethylpropyl group, 2,2-dimethyl-1-ethylpropyl group, 1,2-dimethyl-1-ethylpropyl group, 1-isopropyl-2-methylpropyl group, cycloheptyl group, cyclohexylmethyl group, Methyl cyclohexyl group, octyl group, 1-methylheptyl group, 2-methylheptyl group, 1-ethylhexyl group, 2-ethylhexyl group, 1,1,3,3-tetramethylbutyl group, 1,1-diisopropylethyl group, 1-ethyl-1,2,2-trimethylpropyl group, 1,5-dimethylhexyl group, 3,5-dimethylhexyl group, 2-propylpentyl group, 2,4,4-trimethylpentyl group, 1-ethyl- 2-methylpentyl group, 2,2-dimethylhexyl group, 1,1-dimethylhexyl group, cycloheptylmethyl group, dimethylcyclohexyl group, 4-methylcyclohexylmethyl group, cycloheptylmethyl group, cyclooctyl group, 1-cyclohexyl Ethyl group, 2-cyclohexylethyl group, ethyl cyclohexyl group, a nonyl group, 1-methyl octyl group, 5-methyl-octyl group, 1- (2'-methylpropyl) -3-methylbutyl group,
3,5,5-trimethylhexyl group, 1,1-diethyl-2,2-dimethylpropyl group, 3-cyclohexylpropyl group, 1,1-dimethylheptyl group, decyl group, 1-methylnonyl group, 1-propylheptyl group Group, 3,7-dimethyloctyl group, 2,4,6-trimethylheptyl group, 4-cyclohexylbutyl group, butylcyclohexyl group, 3,3,5,5-tetramethylcyclohexyl group, undecyl group, 1-methyldecyl group , 2-methyldecyl group, 2-ethylnonyl group, dodecyl group, 1-methylundecyl group, 2-methylundecyl group, 2-ethyldecyl group,
1- (2'-methylpropyl) -3,5-dimethylhexyl group, tridecyl group, 2,4,6,8-tetramethylnonyl group, 2-methyldodecyl group, 2-ethylundecyl group, 1- ( 3'-methylbutyl) -6-methylheptyl group, 1- (1'-methylbutyl) -4-methylheptyl group, tetradecyl group, 1-methyltridecyl group, 2-methyltridecyl group, 2-ethyldodecyl group, 2-
(3'-methylbutyl) -7-methyloctyl group, 2- (1'-methylbutyl) -5-methyloctyl group, pentadecyl group, 1-hexylnonyl group, 2-methyltetradecyl group, 2-ethyltridecyl group , Hexadecyl group, 1-methylpentadecyl group,
2-hexyldecyl group, heptadecyl group, 1-heptyldecyl group, 1- (1 ', 3', 3'-trimethylbutyl) -4,6,6-trimethylheptyl group, 1- (3'-methylhexyl)- 6-methylnonyl group, octadecyl group, 2-heptylundecyl group, 2- (1 ',
3 ', 3'-trimethylbutyl) -5,7,7-trimethyloctyl group, an alkyl group such as 2- (3'-methylhexyl) -7-methyldecyl group, a phenyl group, 2- or 3- or 4 -Methylphenyl group, 2- or 3- or 4-ethylphenyl group, 2,3- or 2,4- or 2,5- or 2,6- or 3,4- or 3,5-dimethylphenyl group,
2-or 3-or 4-isopropylphenyl group, 2-or 3-or
4-propylphenyl group, 2,3,5- or 2,3,6- or 2,4,6- or 3,4,5-trimethylphenyl group, 2- or 3- or 4-tert-
Butylphenyl group, 2- or 3- or 4-sec-butylphenyl group, 4- or 5-isopropyl-3-methylphenyl group, 4-te
rt- Amylphenyl group, 3- or 4- or 5-methyl-2-tert-
Butylphenyl group, pentamethylphenyl group, naphthyl group, 2-methylnaphthyl group, 2,6-diisopropylphenyl group, 4-tert-octylphenyl group, 2,4- or 2,6- or 3,
5-di-tert-butylphenyl group, di-sec-butylphenyl group, 2,6-di-tert-butyl-4-methylphenyl group, 2,4,6-
Aryl group such as tri-tert-butylphenyl group, an alkylaryl group, a benzyl group, a 2- or 3- or 4-methylbenzyl group, a phenethyl group, a sec-phenethyl group, 2,4- or 2,
5-or 3,4- or 3,5-dimethylbenzyl group, 4-ethylbenzyl group, 2- or 3- or 4-methylphenethyl group, α- or β-methylphenethyl group, α, α-dimethylbenzyl group , 1- or 3-phenylpropyl group, α- or β-ethylphenethyl group, 4-isopropylbenzyl group, α-isopropylbenzyl group, α, α-dimethylphenethyl group, 1-
Or 3- or 4-phenylbutyl group, α-ethyl-α-methylbenzyl group, 4-butylbenzyl group, 4-tert-butylbenzyl group, 1,1-dimethyl-3-phenylpropyl group, 1- or 3 Examples include aralkyl groups such as -phenyl-2,2-dimethylpropyl group, α-propylphenethyl group, 5-phenylpentyl group, naphthylmethyl group, naphthylethyl group and 6-phenylhexyl group.

R ¹ and R ³ are an alkyl group having 1 to 18 carbon atoms, an aryl group, an alkylaryl group, an aralkyl group, or a group represented by — (R ⁵ O) k—R ⁴ . Specific examples of the alkyl group having 1 to 18 carbon atoms, the aryl group, the alkylaryl group, and the aralkyl group are the same as those listed for R ⁴ . It preferably has 1 to 10 carbon atoms, and if the number of carbon atoms exceeds 18, the compatibility with hydrofluorocarbon becomes poor.

R ² and R ⁵ are an alkylene group having 2 to 18 carbon atoms, an arylene group, an alkylarylene group or an aralkylene group. The number of carbon atoms is preferably 2 to 10, and if the number of carbon atoms exceeds 18, the compatibility with hydrofluorocarbon becomes poor. Specific examples include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol,
1,4-butanediol, 2,3-butanediol, 2-methyl-
1,2-propanediol, 2-methyl-1,3-propanediol, 1,2-pentanediol, 1,3-pentanediol,
1,4-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 2,2-dimethyl-1,3-propanediol, 1,3-cyclopentanediol, 1,2-hexanediol, 1 , 5-hexanediol, 1,6-hexanediol, 2,
5-hexanediol, 3,3-dimethyl-1,2-butanediol, 2-ethyl-2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 2,3-dimethyl- 2,3-butanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2,2-
Diethyl-1,3-propanediol, 2-isopropyl-2-
Methyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 1,7-pentanediol, 2-ethyl-1,3
-Hexanediol, 2,5-dimethyl-2,5-hexanediol, 1,2-octanediol, 1,8-octanediol,
2,2,4-trimethyl-1,3-pentanediol, 2-n-butyl
-2-Ethyl-1,3-propanediol, 1,9-nonanediol, 1,2-decanediol, 1,10-decanediol, 1,2-
Dodecanediol, 1,12-dodecanediol, 1,2-tetradecanediol, 1,14-tetradecanediol, 1,2-
Hexadecanediol, 1,16-hexadecanediol,
Alkylene groups which are alcohol residues of dihydric alcohols such as 1,2-octadecanediol and 1,18-octadecanediol, catechol, resorseal, 2- or 3- or 4-hydroxybenzyl alcohol, 3- or 4-methyl Catechol, 2-methylresorcinol, 1,2- or 1,3- or 1,4-benzenedimethanol, 4-ethylresorcinol, 2-or
3- or 4-hydroxyphenethyl alcohol, 1-phenyl
-1,2-ethanediol, 3- (4-hydroxyphenyl) -1-
Propanol, 2-phenyl-1,2-propanediol, 4-
tert-butylcatechol, 4-hexylresorcinol,
Divalent phenol such as 3,5-diisopropylcatechol, α, α, α ', α'-tetramethyl-1,4-benzenedimethanol, 3,5-di-tert-butylcatechol, 4-dodecylresorcinol or An arylene group, which is a residue of alcohol,
Examples thereof include an alkylarylene group and an aralkylene group.

K represents an integer of 1 to 100, preferably an integer of 1 to 50, more preferably an integer of 1 to 30. When it exceeds 100, the viscosity is increased and the hygroscopicity is also increased, which is not preferable. m represents an integer of 0 to 100, preferably an integer of 1 to 50, and more preferably an integer of 1 to 30. When it exceeds 100, the viscosity is increased and the hygroscopicity is also increased, which is not preferable. n represents an integer of 0 to 100, preferably 1 to 50
Is an integer of 1 to 30, more preferably an integer of 1 to 30. When it exceeds 100, the viscosity is increased and the hygroscopicity is also increased, which is not preferable.

These carbonates are generally monovalent and / or
Alternatively, it can be obtained by a transesterification reaction of one or more dihydric alcohols or phenols with a carbonic acid ester such as dimethyl carbonate or diethyl carbonate. The lower the acid number of these carbonates, the better, usually 0.1 mgK
OH / g or less, particularly 0.05 mgKOH / g or less is preferable. Acid value is 0.
If it exceeds 1 mgKOH / g, the corrosiveness to metals may increase, which is not preferable. The carbonate of the present invention generally has poor compatibility with a hydrofluorocarbon-based refrigerant at low temperatures as the viscosity increases. Therefore, the ester which is preferable in terms of compatibility has a kinematic viscosity at 100 ° C. of 1 cst or more and 100 cst or less, and more preferably 1 cst or more and 30 cst or less. The ester and carbonate used in the present invention preferably have a low two-phase separation temperature from hydrofluorocarbon, and are preferably 0 ° C. or lower, preferably −10 ° C. or lower, and particularly preferably −30 ° C. or lower. Further, the esters and carbonates A), B), used in the present invention,
When two or more of C) and D) are mixed and used, the mixing ratio of these is not particularly limited.

Refrigerating machine oils having a synthetic oil as a base oil used in the present invention are mineral oils, poly α-olefins, alkylbenzenes, esters and carbonates other than the above, and polyethers, as long as the compatibility with hydrofluorocarbons is not impaired. , Synthetic oils such as perfluoropolyether and phosphoric acid ester may be mixed. Refrigerating machine oils containing ester or carbonate as a base oil used in the present invention have a melting point of 10
The content of the compound at a temperature of not less than 0 ° C is 500 ppm or less, preferably 100 ppm or less, more preferably 50 ppm or less. If it is contained in excess of 500 ppm, it may be deposited in a dryer, a capillary tube, an evaporator, or the like. Further, the higher the melting point, the more the compound may be precipitated, and it is not particularly preferable that the content of the compound having a melting point of 30 ° C. or higher, further 50 ° C. or higher, exceeds 500 ppm.

Examples of the compound having a melting point of 10 ° C. or higher include carboxylic acids, alcohols and phenols which are raw materials of esters and carbonates. Especially for ester (a)
Some of the polyhydric alcohols listed as components, the (c) components of esters and the polycarboxylic acids listed as components of (e), and the dihydric alcohols and phenols listed as raw materials for R ² of carbonates have melting points of 10 ° C. These are examples of the above compounds. To reduce the content of these compounds to 500 ppm or less, 1. 1. Promote the reaction as much as possible so that no unreacted raw material remains. There are methods such as removing unreacted raw materials by distillation or washing with water.

Further, as another example of the compound having a melting point of 10 ° C. or higher, an additive can be mentioned. Especially antioxidant is not preferred, specifically, 2,6-di-t-butylphenol,
2,6-di-t-butyl-4-methylphenol, 4,4'-methylenebis (2,6-di-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 2,2'-
Methylenebis (4-ethyl-6-t-butylphenol), 2,
2'-methylenebis (4-methyl-6-t-butylphenol), 4,4'-isopropylidenebisphenol, 2,4-dimethyl-6-t-butylphenol, tetrakis [methylene
-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1, 3,5-Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 2,2'-dihydroxy-3,3'-di (α-
Methylcyclohexyl) -5,5'-dimethyl-diphenylmethane, 2,2'-isobutylidene bis (4,6-dimethylphenol), bis [3,3-bis- (4'-hydroxy-3'-t- Butylphenyl) butyric acid glycol ester, 2,
6-bis (2'-hydroxy-3'-t-butyl-5'-methylbenzyl) -4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, p, p-dioctylphenylamine , Monooctyldiphenylamine, phenothiazine, 3,7-dioctylphenothiazine, phenyl-1-naphthylamine, phenyl-2-naphthylamine, alkylphenyl-1-naphthylamine, alkylphenyl-2-naphthylamine, N, N'-diphenyl-p-phenylene Diamine,
N, N'-di-β-naphthyl-p-phenylenediamine, N, N '
-Bis (1-methylheptyl) -p-phenylenediamine and the like. Benzotriazole and benzotriazole derivatives are also not preferable, and specifically, benzotriazole, 5-methyl-1H-benzotriazole, 1-dioctylaminomethylbenzotriazole, 1-dioctylaminomethyl-5-methylbenzotriazole, 2 -(Five'
-Methyl-2'-hydroxyphenyl) benzotriazole, 2- [2'-hydroxy-3 ', 5'-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2-
(3 ', 5'-di-t-butyl-2'-hydroxyphenyl) benzotriazole, 2- (3'-t-butyl-5'-methyl-2'-hydroxyphenyl) -5-chlorobenzotriazole, 2-
(3 ', 5'-Di-t-butyl-2'-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3', 5'-di-t-amyl-2'-
Hydroxyphenyl) benzotriazole, 2- (5'-t-
Butyl-2'-hydroxyphenyl) benzotriazole,
2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl)
Benzotriazole, 2- [2'-hydroxy-3 '-(3 ", 4",
5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole and the like. In addition, among the lubricating oil additives such as the epoxy compound, the extreme pressure agent, the oiliness improver, the metal deactivator and the defoaming agent, those having a melting point of 10 ° C. or higher are not preferable. When such an additive is used, it is desirable that the added amount be 500 ppm or less.

The refrigerator working fluid composition of the present invention can be easily prepared by blending hydrofluorocarbon and the refrigerator oil used in the present invention by a conventional method. The blending ratio is usually hydrofluorocarbon / oil = 5/1 to 1/10 (weight ratio), preferably 2/1 to
It is 1/5 (weight ratio). Hydrofluorocarbons used in the present invention include difluoromethane (HFC32), 1,
1-difluoroethane (HFC152a), 1,1,1-trifluoroethane (HFC143a), 1,1,1,2-tetrafluoroethane (HFC134a), 1,1,2,2-tetrafluoroethane (HFC13
4), pentafluoroethane (HFC125), etc.
1,1,1,2-Tetrafluoroethane and difluoromethane are preferred.

[0041]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited thereto. Example A compressor was installed in a test stand equipped with a refrigeration system equivalent to a commercially available domestic refrigerator, and Table 1 was used.
After 200 g of the refrigerating machine oil shown in 1 and HFC134a100 cc were sealed and continuously operated for 500 hours, it was examined whether or not there was a deposit on the capillary tube or the evaporator. The synthetic oils A, B, C and D used are shown below, and the results are shown in Table 1. As is clear from Table 1, the content of the compound having a melting point of 10 ° C. or higher is 5 with respect to the refrigerating machine oil.
The product of the present invention having a content of 00 ppm or less is good because there are no deposits on the capillary tube or the evaporator.

Synthetic oil A: neopentyl glycol / adipic acid (0.35 mol), 2-ethylhexanoic acid (1.20 mol) ester [mole ratio in parentheses to 1 mol of neopentyl glycol] 40 ° C. viscosity: 22.6 cSt 100 C. Viscosity: 4.4
1cSt ・ Critical dissolution temperature with HFC134a: -60 ° C or lower ・ Unreacted raw material: neopentyl glycol (melting point: 123
Content of 50 ppm adipic acid (melting point: 152-154 ° C.) content of 10 p
pm or less

Synthetic oil B: trimethylolpropane tri 3,5,5-trimethylhexanate 40 parts by weight trimethylolpropane tri-2-ethylhexanate 60 parts by weight 40 ° C. viscosity: 32.4 cSt 100 ° C. viscosity: 5.3
3cSt-Critical dissolution temperature with HFC134a: -36 ° C-Unreacted raw material: trimethylolpropane (melting point: 60-
62 ° C) content is 25 ppm

Synthetic oil C: neopentyl glycol / adipic acid (0.35 mol) / 2-ethylhexanoic acid (1.20 mol) ester [mole ratio in parentheses to 1 mol of neopentyl glycol] 40 ° C. viscosity: 22.6 cSt 100 C. Viscosity: 4.4
1cSt ・ Critical dissolution temperature with HFC134a: -60 ° C or lower ・ Unreacted raw material: neopentyl glycol content 100
0ppm Adipic acid content is 10ppm or less

Synthetic oil D: Bis {2- [2- (2-methoxyethoxy) ethoxy] ethyl} carbonate-40 ° C viscosity: 57.5 cSt 100 ° C viscosity: 10.
Critical dissolution temperature with 1 cSt HFC134a: -60 ° C or lower

[0046]

[Table 1]

[0047]

The composition for a working fluid for a refrigerator according to the present invention, by containing a specific refrigerating machine oil, is excellent in compatibility with hydrofluorocarbons, electric insulation, and hygroscopicity, and more particularly, it is more capillary than conventional ones. It is a composition that is unlikely to cause blockage of the tube.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10N 20:00 A 8217-4H 30:04 40:30

Claims (1)

[Claims] 1. A) (a) an aliphatic polyhydric alcohol having 1 to 6 primary hydroxy groups and (b) 2 to 9 carbon atoms.
An ester obtained from the linear or branched saturated aliphatic monocarboxylic acid or its derivative of B) (a) an aliphatic polyhydric alcohol having 1 to 6 primary hydroxy groups, and (b) a carbon number of 2 to 2 (9) a straight-chain or branched-chain saturated aliphatic monocarboxylic acid or derivative thereof
An ester obtained from a linear or branched saturated aliphatic dicarboxylic acid having 2 to 10 carbon atoms or a derivative thereof C) (a) an aliphatic polyhydric alcohol having 1 to 6 primary hydroxy groups, and (d) An ester obtained from a straight-chain or branched-chain saturated aliphatic monohydric alcohol having 1 to 10 carbon atoms and (e) a polyvalent carboxylic acid having 2 to 10 carbon atoms or a derivative thereof, and D) represented by the formula (I) Carbonate represented: (In the formula, R ¹ and R ³ are alkyl groups having 1 to 18 carbon atoms, aryl groups, alkylaryl groups, aralkyl groups,
Alternatively, it represents a group represented by — (R ⁵ O) k—R ⁴ .
However, R ⁴ is an alkyl group having 1 to 18 carbon atoms, an aryl group, an alkylaryl group or an aralkyl group, R ⁵ is an alkylene group having 2 to 18 carbon atoms, an arylene group, an alkylarylene group or an aralkylene group, and k is 1-100
And the k R ⁵ O may be the same or different. R ² is an alkylene group having 2 to 18 carbon atoms, an arylene group, an alkylarylene group or an aralkylene group, m is an integer of 0 to 100, n is an integer of 0 to 100, and m R ² O are the same. May or may not be present, and n number of May be the same or different. (4) A refrigerating machine oil comprising one or more synthetic oils selected from the group consisting of the following) as a base oil, wherein the refrigerating machine oil has a melting point of 10 ° C. or higher and a compound content of 500 ppm or lower, and hydrofluorocarbons. A composition for a working fluid of a refrigerator containing the composition.