JPH0420597A - Refrigerator oil for hydrofluorocarbon refrigerant - Google Patents

Abstract

PURPOSE:To obtain a refrigerator oil excellent in compatibility with a hydrofluorocarbon and having a high electric insulating property by incorporating a specific polyol ester as a main component. CONSTITUTION:A refrigerator oil comprising a specific polyol ester represented by formula I as a main component. In the formula, R1, R2 and R3 may be identical or different and are each a 3-11C straight chain alkyl, a 3-15C branched alkyl or a 6-12C cycloalkyl (here, the proportion of the straight chain alkyl is 60% or less to the total alkyl groups); R4 is methyl, ethyl or propyl; and n represents 1-3. As the refrigerator oil, said polyol ester may be used singly, but a mixture of the ester with other refrigerator base oil may also be used as required. A preferred base oil may include polyoxy-alkylene glycols represented by formula II (wherein R5 and R6 are each H or a 1-18C alkyl; R7 is a 2-4C alkylene group; and a is 5-70) and esters thereof.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a hydrogen-containing fluorocarbon refrigerant refrigerating machine oil, and more specifically, the present invention relates to a hydrogen-containing fluorocarbon refrigerant refrigerant oil that has a polyol ester having a specific structure as a main component and has excellent various performances. This 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-113, HCFC-
22 etc. are used.

Among these fluorocarbon refrigerants, CFC-11, CFC-
12. CFC-113 and other hydrocarbons in which all the hydrogen has been replaced with halogens including chlorine are subject to regulations as they lead to the destruction of the ozone layer. Therefore,
Hydrogen-containing fluorocarbons such as RF C-134a and HF C-152a are being used as substitutes for CFCs, but RF C-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, which makes it 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-13.
Since it has almost no compatibility with hydrogen-containing fluorocarbons such as 4a, when used in combination with RFC-134a, two-layer separation will occur at room temperature, impairing the oil return property that is most important in the refrigeration system, and reducing refrigeration efficiency. The deterioration or poor lubricity results in various practical inconveniences 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 HF C-134a, so the same problems as above occur and they cannot be used practically.

Also, in U.S. Patent No. 4,755,318, RF C-
A polyglycol-based refrigeration oil that is compatible with 134a is disclosed. In addition, the present inventors have discovered that HF C-134
We have previously developed a polyglycol-based refrigerating machine oil that has significantly better compatibility with A than conventional refrigerating machine oils, and have already filed an application (Japanese Unexamined Patent Publication Nos. 1-256594 and 1-256594).
271491, etc.). However, it has been found that polyglycol oils have problems in that they are highly soluble in water and have poor electrical insulation properties.

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 hydrogen-containing fluorocarbons such as FC-134a. Therefore, a refrigerating machine oil that has both high compatibility with hydrogen-containing 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 is HF.
Excellent compatibility with hydrogen-containing 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
An object of the present invention is to provide a lubricating oil for a hydrogen-containing fluorocarbon refrigerant that has excellent compatibility with hydrogen-containing fluorocarbons such as FC-134a and has high electrical insulation properties.

[Means for Solving the Problems] That is, the present invention provides the following: [In the formula, R1-R3 may be the same or different, and each represents a linear alkyl group having 3 to 11 carbon atoms, and 3 to 1 carbon atoms.
5 branched alkyl groups and cycloalkyl groups having 6 to 12 carbon atoms, provided that the proportion of straight chain alkyl groups is 60% or less of the total alkyl groups) R4
represents a group selected from the group consisting of a methyl group, an ethyl group, and a propyl group, and n represents an integer of 1 to 3.] A hydrogen-containing fluorocarbon refrigerant characterized by containing a polyol ester as a main component. The company provides refrigerating machine oil for commercial use.

Hereinafter, the content of the present invention will be explained in more detail.

The refrigerating machine oil of the present invention has a polyol ester represented by -shipman as a main component. In the above formula, R1-R3 may be the same or different, and each is a linear alkyl group having 3 to 11 carbon atoms, preferably 3 to 7 carbon atoms, or a branched alkyl group having 3 to 15 carbon atoms, preferably 4 to 11 carbon atoms. , and carbon number 6-12, preferably 6-12
8 represents a group selected from the group consisting of cycloalkyl groups. In addition, the cycloalkyl group as used in the present invention also includes an alkylcycloalkyl group. Also, R1-R
For 3, the proportion of straight chain alkyl groups is 60% or less, preferably 50% of all alkyl groups (including cycloalkyl groups).
% or less. Further, R4 represents a group selected from the group consisting of methyl group, ethyl group and propyl group. Furthermore, n represents an integer of 1 to 3. That is, the above formula shows trimethylol ethane ester, trimethylol propane ester, trimethylol butane ester, and esters of dimers and trimers thereof. It is not preferable to use a polyol ester that does not meet the above conditions as the main component because it has poor compatibility with hydrogen-containing fluorocarbons.

Specifically, R1-R3 includes, for example, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group,
n-hebutyl group, n-octyl group, n-nonyl group, n-
Decyl group, n-undecyl group, 1so-propyl group, j
so-butyl group, 1so-pentyl group, 15O-hexyl group, 15O-heptyl group, 1so-octyl group, 1s
o-nonyl group, 1so-decyl group, 1so-undecyl group, 1so-dodecyl group, 1so-)lysosyl group, l5
O-tetradecyl group, 1so-pentadecyl group, cyclohexyl group, cyclohebutyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, cycloundecyl group,
Examples thereof include a cyclododecyl group, a methylcyclohexyl group, an ethylcyclohexyl group, a propylcyclohexyl group, a butylcyclohexyl group, a pentylcyclohexyl group, and a hekylenecyclohexyl group.

The polyol ester used in the present invention is an ester of trimethylolethane, trimethylolpropane, trimethylolbutane, or a dimer or trimer thereof and a monocarboxylic acid, and is usually trimethylolethane, trimethylolpropane, or trimethylolbutane. It is obtained by reacting methylolbutane, dimers or trimers thereof, or mixtures thereof with one or a mixture of two or more of the above-mentioned alkyl group-containing carboxylic acids. The obtained product may be purified to remove by-products and unreacted substances, but small amounts of by-products and unreacted substances may be removed as long as they do not adversely affect the excellent performance of the refrigeration oil of the present invention. , there is no problem even if it exists.

As the polyol ester used in the present invention, any compound having the structure shown in the above formula can be used, but the kinematic viscosity is 2 to 2 at 100°C.
150 cst, preferably 5 to 100 cst.

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

General formula % Formula % [In the formula, R5 and R6 represent hydrogen or an alkyl group having 1 to 18 carbon atoms, R7 represents an alkylene group having 2 to 4 carbon atoms, and a represents an integer of 5 to 70] The represented polyoxyalkylene glycol or its ether.

HC-0÷R120-)-Rs H2C-0+ Rrs O+;y R+.

[In the formula, R8 to R1o represent hydrogen or an alkyl group having 1 to 18 carbon atoms, R11 to R43 represent an alkylene group having 2 to 4 carbon atoms, and b-d represents an integer of 5 to 7] polyoxyalkylene glycol glycerol ether.

The group represented by the general formula, an alkyl group having 1 to 15 carbon atoms; RI8 and R1 each represent an alkyl group having 1 to 14 carbon atoms; e and f each represent a number of 0 or 1; and n represents an integer of 0 to 30. Esters represented.

General formula [wherein Yl and Y2 may be the same or different, each represents a methyl group, an ethyl group, a propyl group, or a group represented by the general formula -CH2-0CR22, and R22 to R26 are An alkyl group having 3 to 15 carbon atoms, R
2, represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and h
represents an integer of 1 to 5] A polyol dicarboxylic acid ester represented by:

- Boatman [wherein R28 to R3 are a group selected from the group consisting of 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; However, the proportion of straight-chain alkyl groups is the total alkyl group (
60% or less of (containing cycloalkyl groups),
In addition, 1 represents an integer of 1 to 3.] A pentaerythritol ester represented by:

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 hydrogen-containing chlorofluorocarbon solvents will be poor.

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 proportion of polyol ester is usually 50% by weight based on the total amount of the refrigerating machine oil. It is blended in an amount of 70% by weight or more, 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 phosphate ester include tributyl phosphate, triphenyl phosphate, tricresyl phosphate, and the like. Examples of the acidic phosphoric acid esters include ditetradecyl acid phosphate, diventadenyl acid phosphate, dihexadecyl acid phosphate, diheptadenyl 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, cyhexylamine, dioctylamine, 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, tris chlorophenyl phosphate, and the like. 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 it in a proportion of 0.2 to 2.0% by weight, preferably 0.2 to 2.0% by weight.

Furthermore, in order to further improve the stability of the refrigeration oil of the present invention, at least one member 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 is added. 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 3 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, heptylphenyl 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 the epoxidized vegetable oil 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 2% by weight based on the total amount of refrigerating machine oil.
．． It is desirable to contain it in a proportion of 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-phenylenediamine,
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 the polyol ester of the present invention as a main component only needs to have a kinematic viscosity and a pour point that are normally used as refrigeration oil, but in order to prevent the refrigeration oil from solidifying at low temperatures, It is desirable that the pour point is below 110°C, preferably between -20°C and -80°C. 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. It is desirable that it be 150 cSt or less, preferably 100 cSt or less.

The refrigerating machine oil of the present invention has significantly better compatibility with hydrogen-containing fluorocarbons than conventionally known refrigerating machine oils. Specifically, hydrogen-containing fluorocarbons include 1,1.2゜2-tetrafluoroethane (HF C134>, 11.1.2-tetrafluoroethane (RF C-134a), 1,1-difluoroethane (RF C- 152a) Trifluoromethane (RFC-23) and the like are exemplified, but RF C-134a is preferred.

Furthermore, the refrigerating machine oil of the present invention not only has high compatibility with hydrogen-containing fluorocarbons and high electrical insulation properties, but is also an excellent refrigerating machine oil with high lubricity and low hygroscopicity.

The refrigeration oil of the present invention can be used in air conditioners with reciprocating or rotary compressors, dehumidifiers, refrigerators, freezers, frozen and refrigerated warehouses,
It can be particularly preferably used for cooling devices such as vending machines, showcases, and chemical plants, but it can also be preferably used for those having centrifugal compressors.

[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. Trimethylolpropane (1moJ) and 2
- Triester of ethylhexanoic acid (3 moJ).

Example 2 Nitrimethylolpropane (1 mo)) and 3
．． Triester of 5.5-trimethylhexanoic acid (3 moJ).

Example 3 Nitrimethylolpropane (lIllo) and 2-ethylhexanoic acid (1,5 moJ) and 3,
Triester of 5゜5-trimethylhexanoic acid (1,5mo).

Example 4 Nidi-(trimethylolpropane) (IIIl
o)) and tetraesters of n-hexanoic acid (2 moJ) and 2°4-dimethylpentanoic acid (2 moJ).

or -CH-CH2-CH-CHs (10oJ), 3.5.5-trimethylhexanoic acid (
4rnoJ) tetraester.

Example 6/A mixture of 50 parts of the ester of Example 1 and 50 parts of the ester of Example 5.

Example 7: 30 parts by weight of the ester of Example 2, Example 5
The ester of
! ) is mixed with 30 parts by weight of octaester.

Q7-C)-Co-F? Comparative Example 1: Naphthenic mineral oil (kinematic viscosity at 100°C: 5.2
cst).

Comparative Example 2: Branched alkylbenzene (kinematic viscosity at 100°C; 5.Ocst).

Comparative Example 3: Polyoxypropylene glycol monobutyl ether (kinematic viscosity at 100°C: 5.4C8t).

Comparative Example 4: Polyoxypropylene glycol dimethyl ether (kinematic viscosity at 100°C; 9.5 cst).

Comparative Example 5 Nitrimethylolpropane (1 moJ') and n
- triester of nonanoic acid (3 moJ).

Comparative Example 6, triester of trimethylolpropane (lIIloJ) and coconut oil.

In order to evaluate the performance of the base oils of the refrigerating machine oils of Examples 1 to 7 according to the present invention, the solubility with RFC-134a, insulation properties, and Falex abrasion test were evaluated. For comparison, Table 1 also shows the test results of mineral oil, alkylbenzene, polypropylene glycol monoalkyl ether, and polypropylene glycol dialkyl ether, which have been conventionally used in refrigeration oil.

(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 220 mm, and the refrigerant (RF
C-134a) Collect 1.8g and seal it in a glass tube. This glass tube is placed in a low-temperature bath or high-temperature bath at a predetermined temperature, and it is observed whether the refrigerant and sample oil are mutually dissolved, separated, or cloudy.

(Insulating properties) The volume resistivity of the sample oil at 25° C. was measured in accordance with JISC2101.

(FALEX wear test) In accordance with ASTM D 2670, the sample oil temperature was 100°C, and after a 1-minute break-in operation with a load of 150 Jb, the tester was operated for 2 hours under a load of 250 Jb.
The amount of wear on the test journal was measured.

(Hygroscopicity) Take 30g of sample oil in a 300d heater and heat at 60°C for 3
After standing for 7 days in a constant temperature and humidity chamber maintained at 0% humidity, 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-1 than Comparative Examples 1 to 2 and 5 to 6.
The refrigerant solubility for 34a is very good.

If all the alkyl groups on the acid side are linear as in Comparative Example 5, the solubility is poor. Furthermore, triesters of trimethylolpropane and natural fats and oils, which have been conventionally used in lubricating oils, refrigerator oils, etc., as shown in Comparative Example 6, also have poor refrigerant solubility.

As shown in Comparative Examples 3 and 4, although polyalkylene glycol has excellent refrigerant solubility, it has poor insulation properties and cannot be used in hermetic compressors.

In addition, the alkylene glycols shown in Comparative Examples 3 and 4 are
The moisture absorption amount is 5 to 10 times that of Examples 1 to 7, and it is inferior to each Example in terms of electrical insulation, ice choke, abrasion resistance, stability, etc.

In addition, in the wear test by Falex, Example 1
It can be seen that Comparative Examples 3 to 7 are equivalent to or higher than Comparative Examples 3 to 4.

[Effects of the Invention] As is clear from the above explanation and examples, the refrigerating machine oil of the present invention is suitable for use in refrigerators for hydrogen-containing fluorocarbons, and has excellent electrical insulation properties, which are essential for close-contact type compressors. It is a refrigerating machine oil with excellent wear resistance and non-hygroscopicity.

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R_1 to R_3 may be the same or different, and each represents a linear alkyl group having 3 to 11 carbon atoms, 3
Indicates a group selected from the group consisting of ~15 branched alkyl groups and cycloalkyl groups having 6 to 12 carbon atoms (however, the proportion of straight chain alkyl groups is 60% or less of all alkyl groups)
, R_4 represents a group selected from the group consisting of a methyl group, an ethyl group, and a propyl group, and n represents an integer of 1 to 3.] Freezer oil for fluorocarbon refrigerant. 2. Refrigerating machine oil for a hydrogen-containing fluorocarbon refrigerant according to claim 1, wherein the polyol ester is used as a base oil. 3. (I) The above polyol ester, and (II) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R_5 and R_6 are hydrogen or carbon number 1 to 1]
8 alkyl group, R_7 represents an alkylene group having 2 to 4 carbon atoms, and a represents an integer of 5 to 70] Polyoxyalkylene glycol or its ether represented by the general formula ▲ Numerical formula, chemical formula, table etc. ▼ [In the formula, R_8 to R_1_0 are hydrogen or carbon number 1 to 1
8 alkyl group, R_1_1 to R_1_3 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 ▲ Numerical formula, There are chemical formulas, tables, etc. ▼ [In the formula, There are tables etc. The groups represented by ▼ are shown respectively, and R_1_4 and R_2_0 have 1 to 8 carbon atoms.
R_1_5 and R_1_7 are alkylene groups having 2 to 16 carbon atoms, R_1_6 and R_2_1
is an alkyl group having 1 to 15 carbon atoms, R_1_8 and R_
1_9 each represents an alkyl group having 1 to 14 carbon atoms,
In addition, e and f represent the number 0 or 1, and n represents an integer from 0 to 30.] Ester represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, Y_1 and Y_2 are the same However, they may be different, and each represents a methyl group, ethyl group, propyl group, or a group represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼, and R_2_2 to R_2_6 are alkyl groups having 3 to 15 carbon atoms. group, R_2_7 represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and h represents an integer of 1 to 5], and a polyol dicarboxylic acid ester represented by the general formula ▼ [In the formula, R_2_8 to R_3_1 represent a group selected from the group consisting of 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. (However, the proportion of straight-chain alkyl groups is 80% or less of all alkyl groups (including cycloalkyl groups)), and i represents an integer of 1 to 3] The refrigerating machine oil for a hydrogen-containing fluorocarbon refrigerant according to claim 1, wherein the base oil is a mixed oil of at least one type of oil selected from the group consisting of: 4. (I) The refrigerating machine oil for a hydrogen-containing fluorocarbon refrigerant according to claim 3, wherein the polyol 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 hydrogen-containing 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.