JPH03200896A - Refrigerator oil for use in chlorine-free fluorocarbon refrigerant - Google Patents

Abstract

PURPOSE:To provide a lubricating oil for sue in a chlorine-free fluorocarbon refrigerant, wherein good compatibility with chlorine-free fluorocarbon and good electrical insulating properties are achieved, by compounding an ester of a specific structure as the principal component. CONSTITUTION:A refrigerator oil consists mainly of an ester shown by the formula (where X represents R3O or R5-CO-O-R4-O; Y represents CO-R6 or CO-(-R7-)m-CO-OR3; R1 and R7 represent 1-8C and preferably 1-6C divalent hydrocarbon groups; R2 and R4 represent 2-16C and preferably 2-9C saturated hydrocarbon groups; R3 and R8 represent 1-15C and preferably 1-12C alkyls; R5 and R8 represent 1-14C and preferably 1-14C alkyls; (l) and (m) are 0 or 1; (n) is 0-30 and preferably 1-30) (e.g. diester of adipic acid with 2-ethyl-1-hexanol). The refrigerator oil is suitable for use in a refrigerator using chlorine-free fluorocarbon such as HFC-134a. It has good electrical insulating properties, wear resistance and nonhygroscopic properties.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a non-chlorine-based fluorocarbon refrigerant refrigerating machine oil, and more specifically, the present invention relates to a non-chlorine-based fluorocarbon refrigerant refrigerant oil, which is mainly composed of an ester having a specific structure and has excellent various performances. This article relates to refrigeration oil for fluorocarbon refrigerants.

[Prior art and problems to be solved by the invention] Conventionally, refrigerating machine oil has a kinematic viscosity of 1O at 40°C.
~200cSt naphthenic mineral oil, paraffinic mineral oil,
Alkylbenzene, polyglycol oil, ester oil, mixtures thereof, or mixtures of these various base oils with additives are generally used.

On the other hand, as a fluorocarbon refrigerant used in refrigerators, CF
C-11, CFC-12, CFC-118, HCFC-
22 etc. are used.

Among these fluorocarbon refrigerants, CFC-11, CFC-
12.CFC-118 and other hydrocarbons in which all the hydrogen is replaced with halogens including chlorine are subject to regulations as they lead to the destruction of the ozone layer. Therefore,
Non-chlorinated fluorocarbons such as RF C-134a and RF C-152a are being used as substitutes for CFCs, but RFC-134a in particular has traditionally been used in many refrigerators such as home refrigerators and air conditioners. It has similar thermodynamic properties to CFC-12 and is a promising alternative refrigerant.

Although refrigerating machine oil has various performance requirements, compatibility with refrigerant is extremely important from the viewpoint of lubricity and system efficiency of the refrigerating machine. However, refrigeration oils based on naphthenic mineral oils, paraffinic mineral oils, alkylbenzenes, and conventionally known ester oils are classified as RF C-11.
Since it has almost no compatibility with non-chlorinated fluorocarbons such as 4a, when used in combination with RFC-1148, two-layer separation occurs at room temperature, impairing oil return, which is the most important property in a refrigeration system, and reducing refrigeration efficiency. This causes various problems in practical use, such as a decrease in lubricity or poor lubricity, such as seizure of the compressor, making it unusable. Polyglycols are also known as refrigerating machine oils having a high viscosity index;
It is described in Japanese Patent Application Laid-Open No. 57-51795, etc. However, the polyglycol oils specifically disclosed in these prior art techniques do not have sufficient compatibility with RF C-134a, so the same problems as above occur and they cannot be used practically.

Also, in U.S. Patent No. 4,755.316, RFC-1
A polyglycol-based refrigerating machine oil that is compatible with No. 34a is disclosed. In addition, the present inventors have previously developed a polyglycol-based refrigerating machine oil that has significantly better compatibility with HFC-134a than conventionally known refrigerating machine oils, and have already filed an application (Japanese Patent Application Laid-Open No. -256594 Publication, 1-27
1491, etc.). However, it has been found that polyglycol oils have the problems of high water solubility and poor electrical insulation.

On the other hand, refrigeration oil used in compressors such as household refrigerators is required to have high electrical insulation properties. Among known refrigeration oils, alkylbenzenes and mineral oils have the highest insulating properties, but as mentioned above, alkylbenzenes and mineral oils have the highest insulating properties.
It has almost no compatibility with non-chlorinated fluorocarbons such as FC-134a. Therefore, a refrigerating machine oil that has both high compatibility with non-chlorinated fluorocarbons such as RF C-134a and high insulation properties has not yet appeared.

As a result of repeated research to develop a refrigerating machine oil that can meet the above requirements, the present inventors discovered that an ester with a specific structure
Excellent compatibility with non-chlorinated fluorocarbons such as C-134a,
They have also discovered that it has high electrical insulation properties and even better lubrication properties, leading to the completion of the present invention.

The present invention provides R
The object of the present invention is to provide a lubricating oil for a non-chlorinated fluorocarbon refrigerant that has excellent compatibility with non-chlorinated fluorocarbons such as FC-134a and has high electrical insulation properties.

[Means to solve the problem] That is, the present invention general formula Hereinafter, the content of the present invention will be explained in more detail.

The refrigerating machine oil of the present invention has the following properties:
The group represented by TE, Y, has as a main component an ester represented by -C-Re or .

In the above formula, X is -0R3 or -0-R4-0-C-R
5, Y is -C-Rs or shown, R1 and R7 are divalent hydrocarbon groups having 1 to 8 carbon atoms, and R2 and R4 are divalent saturated hydrocarbon groups having 2 to 16 carbon atoms. group, R3 and R8 are alkyl groups having 1 to 15 carbon atoms, R5 and R6 are alkyl groups having 1 to 14 carbon atoms, and J and m are 0 or 1, and n
represents an integer from 0 to 30] The present invention provides a refrigerator for a non-chlorine-based fluorocarbon refrigerant characterized by containing an ester represented by the following as a main component.

Moreover, R1 and R7 have 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms.
divalent hydrocarbon group, R2 and R4 have 2 to 16 carbon atoms
, preferably 2 to 9 divalent saturated hydrocarbon groups, R3 and R8 are alkyl groups having 1 to 15 carbon atoms, preferably 1 to 12 carbon atoms, R5 and R6 are 1 to 14 carbon atoms, preferably 1
-11 alkyl groups are shown respectively. Furthermore, J.
and m represents the number of 0 or 1, and n represents an integer of 0 to 30, preferably 1 to 30. It is not preferable to use ester that does not meet the above conditions as the main component because it has poor compatibility with hydrogen-containing fluorocarbons.

Specifically, R1 and R7 include a methylene group, an ethylene group, a propylene group, a trimethylene group, a butylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a phenylene group, and others. Examples of unsaturated groups include R2 and R4, in addition to the above alkylene groups (excluding methylene groups), nonamethylene groups, decamethylene groups, undecamethylene groups, dodecamethylene groups, tridecamethylene groups, and tetradecamethylene groups. , a pentadecamethylene group, a hexadecamethylene group, a cyclohexylene group, and the like. Also, R
5 and R8 are specifically methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group. Examples include straight chain or branched alkyl groups such as R3 and R
Examples of 8 include straight-chain or branched alkyl groups such as the above-mentioned alkyl group, such as a pentadecyl group.

In the present invention, the above esters may be used singly or as a mixture of two or more.

Further, the molecular weight of the ester in the present invention is not particularly limited, but from the viewpoint of further improving the sealing performance of the compressor, those having a number average molecular weight of 200 to 3000 are preferably used; 2000 is more preferably used. Further, the kinematic viscosity of the ester in the present invention is desirably 2 to 150 cSt, preferably 5 to 100 cSt at 100°C.

The method for producing the ester in the present invention is arbitrary, but for example, (a) a diol containing no ether bond in the branch, (
A mixture can be produced at once by subjecting b) dicarboxylic acid and (c) monohydric alcohol and/or monohydric alcohol to an esterification reaction. Also, (a) and (
It can also be produced by reacting C) with a monohydric carboxylic acid, or by reacting (b) with a monohydric alcohol (e).

As (a), those having 2 to 16 carbon atoms are used, specifically ethylene glycol, propylene glycol,
Butylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, heptamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene glycol, neopentyl glycol, 2-
Ethyl 2-methyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2.
2-dimethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-bentanediol, 2,4-bentanediol, 2-methyl-2, Examples include alkylene glycols such as 4-bentanediol, 2-methyl-1,6-hexane, 1,4-cyclohexane dimetatool, and 2,2-bis(4-hydroxycyclohexyl)propane.

As (b), a dicarboxylic acid having 2 to 10 carbon atoms is used, and specifically, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, subaric acid,
Azelaic acid, sebacic acid, methylmalonic acid, ethylmalonic acid, dimethylmalonic acid, methylsuccinic acid, 2,2-
Dimethylsuccinic acid, 2.3-dimethylsuccinic acid, 2-ethyl-2-methylsuccinic acid, 2-methylglutaric acid, 3
-Methylglutaric acid, 3,3-dimethylglutaric acid,
Saturated aliphatic dicarboxylic acids such as 3-methyladipic acid, unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid. etc. are exemplified.

Furthermore, (c) the monovalent carboxylic acid has 2 to 2 carbon atoms.
15 are used, specifically acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, and pentadecanoic acid. acid, 3-methylbutanoic acid, 2-methylbutanoic acid, 2-ethylhexanoic acid, 2.4-dimethylpentanoic acid, 3.3.
Examples include 5-trimethylhexanoic acid and benzoic acid.

In addition, (c) the monohydric alcohol has a carbon number of 1 to 1
5 are used, specifically methanol, ethanol, propatool, butanol, pentanol, hexanol, heptatool, octatool, nonanol,
Decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, isopropanol, isobutanol, 2-methyl-l-butanol, 2,2-dimethyl-1-propanol, 3,3-
Dimethyl-1-butanol, 2-methyl-1-pentanol, 3-methyl-1-pentanol, 2.4.4-trimethyl-1-pentanol, 2,2.4-) dimethyl-1-pentanol, Examples include 2-ethyl-4-methyl l-pentanol and 2-ethyl-■-hexanol.

Although by-products and unreacted substances may be removed by refining the product obtained from the above-mentioned raw materials, small amounts of by-products and unreacted substances may affect the excellent performance of the refrigeration oil of the present invention. There is no problem even if it exists as long as it does not have a negative impact on the environment.

The refrigerating machine oil of the present invention may use the above-mentioned ester alone, but may also be used in combination with other refrigerating machine oil base oils, if necessary. Preferred examples of this base oil include the following.

General formula % Formula % [In the formula, R9 and Rlo are hydrogen or carbon number i to 18
, R1 represents an alkylene group having 2 to 4 carbon atoms, and a represents an integer of 5 to 70.] A polyoxyalkylene glycol or an ether thereof.

HC-0+RIsO Snake-RI3 82C-0-fR170 Of course R14 [wherein, RI2 to R24 represent hydrogen or an alkyl group having 1 to 18 carbon atoms, R15 to R1□ represent an alkylene group having 2 to 4 carbon atoms, b-d represents an integer of 5 to 70] A polyoxyalkylene glycol glycerol ether represented by the following.

[In the formula, RI8 to R21 represent a group selected from a linear alkyl group having 3 to 11 carbon atoms, a branched alkyl group having 3 to 15 carbon atoms, and a cycloalkyl group having 6 to 12 carbon atoms,
A pentaerythritol ester in which the proportion of linear alkyl groups is 60% or less of all alkyl groups, and e is an integer of 1 to 3.

It is represented by the general formula [wherein R2□ to R27 represent an alkyl group having 3 to 15 carbon atoms, R28 represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and f represents an integer of 1 to 5]. pentaerythritol dicarboxylic acid ester.

These oils may be used alone or in combination. In addition, paraffinic and naphthenic mineral oils, polyα
- Oils such as olefins and alkylbenzenes may also be mixed, but in this case, the compatibility with non-chlorinated chlorofluorocarbon solvents decreases.

The blending amount of these base oils is not particularly limited as long as it does not impair the excellent performance of the refrigerating machine oil of the present invention, but the ratio of the ester according to the present invention to the total amount of the refrigerating machine oil is , usually more than 50% by weight, preferably 70% by weight or more.

In the refrigeration oil composition of the present invention, in order to further improve its wear resistance and load carrying capacity, phosphoric acid esters, acidic phosphoric esters, amine salts of acidic phosphoric esters, chlorinated phosphoric esters and phosphorous esters are used. At least one phosphorus compound selected from the group consisting of esters can be blended. These phosphorus compounds are esters of phosphoric acid or phosphorous acid and alkanols, polyether type alcohols, or derivatives thereof. Specifically, examples of the phosphoric acid ester include tributyl phosphate, triphenyl phosphate, tricresyl phosphate, and the like. Examples of the acidic phosphoric acid ester include ditetradecyl acid phosphate, dipentadecyl acid phosphate, dihexadecyl acid phosphate, diheptadecyl acid phosphate, dioctadecyl acid phosphate, and the like. Examples of the amine salts of acidic phosphoric esters include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, Examples include salts with amines such as dipentylamine, diethylamine, diethylamine, dioctylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, trihebutylamine, and trioctylamine. Examples of the chlorinated phosphate ester include tris dichloropropyl phosphate, tris chloroethyl phosphate, polyoxyalkylene bis[di(chloroalkyl)] phosphate, and tris chlorophenyl phosphate. Phosphite esters include dibutyl phosphite, tributyl phosphite, dioctyl phosphite, tripentyl phosphite, didecyl phosphite, trihexyl phosphite, dioctyl phosphite, trihebutyl phosphite, dioctyl phosphite, and trihexyl phosphite. Octyl phosphite, dinonyl phosphite, didecyl phosphite, dioctyl phosphite, triundecyl phosphite, didodecyl phosphite, tridodecyl phosphite, diphenyl phosphite, triphenyl phosphite, didecyl phosphite, tricle Examples include dilphosphite.

Mixtures of these can also be used. When blending these phosphorus compounds, the amount is 0.1 to 5.0 based on the total amount of refrigerating machine oil.
It is desirable to contain 111Z in an amount of % by weight, preferably 0.2 to 2.0% by weight.

In addition, in order to further improve the stability of the refrigeration oil of the present invention, at least one selected from the group consisting of phenyl glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, epoxidized fatty acid heptanoesters, and epoxidized vegetable oils is added. i types of epoxy compounds can be blended. Examples of the phenylglycidyl ether type epoxy compound mentioned here include phenylglycidyl ether and alkylphenylglycidyl ether. The alkylphenyl glycidyl ether here refers to 1 to 1 alkyl groups having 1 to 13 carbon atoms.
Among them, those having one alkyl group having 4 to 10 carbon atoms, such as butylphenyl glycidyl ether, pentylphenyl glycidyl ether, hexylphenyl glycidyl ether, heptylphenyl glycidyl ether, octylphenyl glycidyl ether, nonylphenyl Glycidyl ether and decylphenyl glycidyl ether are preferred. Examples of the glycidyl ester type epoxy compound include phenylglycidyl ester, alkylglycidyl ester, alkenylglycidyl ester, etc., and preferred examples include glycidyl benzoate, glycidyl acrylate, glycidyl methacrylate, etc.

Examples of epoxidized fatty acid monoesters include esters of epoxidized fatty acids having 12 to 20 carbon atoms and alcohols having 1 to 8 carbon atoms, phenols, and alkylphenols. In particular, butyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl, phenyl and butylphenyl esters of epoxystearic acid are preferably used.

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

Preferred among these epoxy compounds are phenyl glycidyl ether type epoxy compounds and epoxidized fatty acid monoesters.

Among these, phenylglycidyl ether type epoxy compounds are more preferred, and phenylglycidyl ether, butylphenylglycidyl ether and mixtures thereof are particularly preferred.

When blending these epoxy compounds, the amount is 0.1 to 5.0% by weight, preferably 0.2 to 5.0% by weight based on the total amount of refrigerating machine oil.
It is desirable to contain it in a proportion of 2.0% by weight.

Moreover, it goes without saying that the above-mentioned phosphorus compound and epoxy compound may be used in combination.

Furthermore, in order to further improve the performance of the refrigerating machine oil in the present invention, conventionally known refrigerating machine oil additives may be added, for example, phenolic additives such as di-tert-butyl-p-cresol, bisphenol A, phenyl -α-naphthylamine, N,N-di(2-naphthyl)
-Amine-based antioxidants such as p-phenyl diamine,
Anti-wear agents such as zinc dithiophosphate, chlorinated paraffin,
Additives such as extreme pressure agents such as sulfur compounds, oily agents such as fatty acids, antifoaming agents such as silicone, and metal deactivators such as benzotriazole can be added singly or in combination. be. The total amount of these additives is usually 10% by weight or less, preferably 5% by weight or less, based on the total amount of refrigerating machine oil.

The refrigeration oil containing ester as a main component of the present invention only needs to have a kinematic viscosity and pour point that are normally used as refrigeration oil, but in order to prevent the refrigeration oil from solidifying at low temperatures, The point is below 110°C, preferably between 20°C and below.
-80°C is desirable. In addition, in order to maintain a tight seal with the compressor, the kinematic viscosity at 100°C is preferably 2 cSt or more, preferably 3 cSt or more. is preferably 150 cSt or less, preferably 100 cSt or less.

The refrigerating machine oil of the present invention has significantly better compatibility with non-chlorinated fluorocarbons than conventionally known refrigerating machine oils. Specific examples of non-chlorinated fluorocarbons include 1,1.2°2-tetrafluoroethane (RFC-134).

1.1.2-tetrafluoroethane (RF C-134
a), 1,1-difluoroethane (RF C-152a
), trifluoromethane (RFC-23), etc., but preferred is RF C-134a.

In addition, the refrigeration oil of the present invention not only has excellent compatibility with non-chlorinated fluorocarbons and electrical insulation properties, but also has high lubricity and
Excellent in low moisture absorption.

The refrigerating machine lubricating oil of the present invention is particularly suitable for cooling equipment such as air conditioners, dehumidifiers, refrigerators, freezers, refrigerated warehouses, vending machines, showcases, chemical plants, etc. that have reciprocating or rotary compressors. Although it can be preferably used, it can also be preferably used in those having a centrifugal compressor.

[Example] Hereinafter, the content of the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Examples 1-7 and Comparative Examples 1-6 Refrigerating machine oil used in the present example and comparative example is shown below.

Example 1: Diester of adipic acid and 2-ethyl-1-hexanol.

Example 2: 3-methyl-1,5-bentanediol and 3
．． 5. Diester of 5-trimethylhexanoic acid.

Hx Example 3: Complex ester of 3-methyl-1,5-bentanediol, adipic acid and 3.5.5-)limethylhexanoic acid with an average molecular weight of about 500° and n≧1 Example 4: Example Same composition as 3, average molecular weight about 700
Example 5: Complex ester of 3-methyl-1,5-bentanediol, adipic acid and 2-ethyl-l-hexanol with an average molecular weight of about 200 RI-0-Co-(CH2)4-Coo-R1 and Example 6: Same composition as Example 5, average molecular weight approximately 75
0° Example 7: Example 3 to which 1.0 g of a phosphate ester type anti-wear agent was added.

Comparative Example 1: Naphthenic mineral oil.

Comparative Example 2: Branched alkylbenzene (average molecular weight approximately 3
00).

Comparative Example 3: Polyoxypropylene glycol monobutyl ether (average molecular weight about 500).

Comparative Example 4: Polyoxypropylene glycol monobutyl ether (average molecular weight about 1000).

Comparative Example 5: Polyoxypropylene glycol (average molecular jl 700).

Comparative Example 6: Polyoxypropylene glycol (average molecular weight approximately 2000).

In order to evaluate the performance of the base oil of the refrigerating machine oil of Examples 1 to 7 related to the present invention, the solubility with RF C-134a, insulation properties,
Falex abrasion test and moisture absorption were evaluated. Also,
For comparison, test results for mineral oil, alkylbenzene, polypropylene glycol monoalkyl ether, which have been conventionally used in refrigeration oil, and polyalkylene glycol disclosed in U.S. Pat. No. 4,755.116 are also listed in Table 1. .

(Solubility with RFC-134a) 0.2 g of the sample oils of Examples and Comparative Examples were collected in a glass tube with an inner diameter of 6 # and a length of 22 t)++ m, and the refrigerant (
RF C-134a) Collect 2g and seal it in a glass tube. Place this glass tube in a low temperature bath or high temperature bath at a predetermined temperature, and check whether the refrigerant and sample oil are mutually dissolved.
Observe if it separates or becomes cloudy.

(Insulating properties) The volume resistance of the sample oil was measured in accordance with JIS C2101. Note that the test temperature was 25°C.

(FALEX wear test) In accordance with ASTM D 2 [i70], the sample oil temperature was 100°C, and after 1 minute of break-in operation with a load of 150 J b, the test was run for 2 hours under a load of 2501 b.
The amount of wear on the test journal was measured.

(Hygroscopicity) Take 30g of sample oil in a 300-cm beaker and heat at 60℃ for 30 minutes.
% humidity for 7 days in a constant temperature and humidity chamber, and then the moisture content was measured by the Karl Fischer method.

As shown in Examples 1 to 7 in Table 1, the refrigerating machine oil according to the present invention has a higher RF C
-134a has excellent refrigerant solubility.

As shown in Comparative Examples 3 to 6, although polyalkylene glycol has excellent refrigerant solubility, it has poor insulation properties and cannot be used in hermetic compressors.

In addition, in the wear test by Falex, Example 1
It can be seen that Comparative Examples 3 and 6 are equivalent to or higher than Comparative Examples 3 and 6.

Regarding the hygroscopicity of water, the refrigerating machine oils of Examples 1 to 7 have lower hygroscopicity and are superior to the alkylene glycols of Comparative Examples 3 to 6.

[Effects of the Invention] As is clear from the above description and examples, the refrigerating machine oil of the present invention is suitable for use in non-chlorinated fluorocarbon refrigerating machines, and has excellent electrical insulation properties, wear resistance, Refrigeration oil with excellent non-hygroscopic properties.

Claims (1)

[Claims] 1. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, X is -OR^3 or a group represented by ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Numerical formulas, chemical formulas, tables, etc. are available ▼ or ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ represents the groups respectively, and R_1 and R_7 are divalent hydrocarbon groups having 1 to 8 carbon atoms, R_2 and R_4 is a divalent saturated hydrocarbon group having 2 to 16 carbon atoms, and R_3 and R_8 are 1 to 16 carbon atoms.
15 alkyl groups, R_5 and R_8 have 1 to 1 carbon atoms
4 each represents an alkyl group, and l and m are 0
or the number of 1, n is an integer of 0 to 30] A refrigerating machine oil for a non-chlorinated fluorocarbon refrigerant, characterized in that the main component is an ester represented by the following. 2. Refrigerating machine oil for non-chlorinated fluorocarbon refrigerant according to claim 1, wherein the ester is used as a base oil. 3. (I) The above ester, and (II) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R_9 and R_1_0 are hydrogen or carbon number 1
~18 alkyl group, R_1_1 has 2 to 4 carbon atoms
[In the formula, R_1_2 to R_1_4 are hydrogen or Carbon number 1
~18 alkyl group, R_1_5 to R_1_7 represent an alkylene group having 2 to 4 carbon atoms, and b to d represent an integer of 5 to 7] Polyoxyalkylene glycol glycerol ether represented by the general formula ▲ Formula , chemical formulas, tables, etc. ▼ [In the formula, R_1_8 to R_2_1 are selected from a straight chain alkyl group having 3 to 11 carbon atoms, a branched alkyl group having 3 to 15 carbon atoms, and a cycloalkyl group having 6 to 12 carbon atoms. The ratio of linear alkyl groups to all alkyl groups is 60
% or less, and e represents an integer from 1 to 3] Pentaerythritol ester represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R_2_2 to R_2_7 are alkyl having 3 to 15 carbon atoms group, R_2_8 represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and f represents an integer of 1 to 5] At least one type selected from the group consisting of pentaerythritol dicarboxylic acid ester represented by The refrigerating machine oil for a non-chlorine-based fluorocarbon refrigerant according to claim 1, wherein the base oil is a mixed oil of . 4. (I) The refrigerating machine oil for a non-chlorinated fluorocarbon refrigerant according to claim 3, wherein the ester is blended in an amount exceeding 50% by weight based on the refrigerating machine oil. 5. At least one phosphorus compound selected from the group consisting of phosphoric acid esters, acidic phosphoric esters, amine salts of acidic phosphoric esters, chlorinated phosphoric esters, and phosphorous esters, based on the total amount of refrigerating machine oil. ~5.0% by weight
The refrigerating machine oil for non-chlorinated fluorocarbon refrigerant according to any one of claims 1 to 4, which contains as an essential component. 6. 0.1 to 5.0 weight of at least one epoxy compound selected from the group consisting of phenyl glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, epoxidized fatty acid monoesters, and epoxidized vegetable oils, based on the total amount of refrigerating machine oil. % as an essential component.