JPH08311472A - Refrigerator oil for nonchlorinated fluorocarbon refrigerant - Google Patents

Abstract

PURPOSE: To prepare a refrigerator oil suitable for nonchlorinated fluorocarbon refrigerants by using a mixed base oil comprising a particular ester and a polyoxyalkylene glycol having a particular structure and/or a pentaerythriotol compd. CONSTITUTION: A refrigerator oil prepared by using a mixed base oil comprising an ester of formula I (wherein X represents OR3 or the like; Y represents a group of formula II or the like; R1 and R7 represent each a 1-8C hydrocarbon; R2 and R4 represent each a 2-16C satd. hydrocarbon; R3 and R8 represent each a 1-15C alkyl; R5 and R6 represent each a 1-14C alkyl; (l) and (m) are each 0 or 1; and (n) is 0 to 30) and at least one member selected among polyoxyalkylene glycols of formula III (wherein R9 and R10 each represent H or a 31-18C alkyl; R11 represents a 2-4C alkylene; and (a) is 5 to 70), ethers thereof, pentaerythritol esters of formula IV (wherein R18 to R21 represent each a 3-11C alkyl with 60% or more of the alkyls being accounted for by straight-chain alkyls; and (e) is 1 to 3), and polyoxyalkylene glycol/glycerol ethers having particular structures. The refrigerator oil has a good compatibility with refrigerants as chlorofluorocarbon substitute, such as HFC-134a, and high electrical insulating properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating machine oil for a non-chlorinated chlorofluorocarbon refrigerant, and more particularly to an ester having a specific structure, a polyoxyalkylene glycol having a specific structure, or pentaerythritol having a specific structure. The present invention relates to a refrigerating machine oil for non-chlorinated CFC refrigerants having excellent various performances using a mixed oil of a kind as a base oil.

[0002]

2. Description of the Related Art Conventionally, as refrigerating machine oil, a naphthenic mineral oil having a kinematic viscosity at 40 ° C. of 10 to 200 cSt,
Paraffinic mineral oils, alkylbenzenes, polyglycol-based oils, ester oils, and mixtures thereof, or mixtures of these base oils with additives are generally used.

On the other hand, CFC-11, CFC-12, and CFC-11 are used as chlorofluorocarbon-based refrigerants used in refrigerators.
3, HCFC-22, etc. are used.

[0004] Among these CFC-based refrigerants, CFC-1
1, CFC-12, CFC-113, etc., are CFCs in which all hydrogens of hydrocarbons are replaced with halogens containing chlorine.
It is subject to regulations for destruction of the ozone layer. Accordingly, non-chlorinated chlorofluorocarbons such as HFC-134a and HFC-152a are being used as substitutes for CFCs.
CFC-1 used in many refrigerators such as air conditioners
It has similar thermodynamic properties to No. 2 and is an effective alternative refrigerant.

Refrigerating machine oil has various required performances, but compatibility with a refrigerant is extremely important in terms of lubricity and system efficiency of the refrigerator. However, refrigeration oils based on naphthenic mineral oils, paraffinic mineral oils, alkylbenzenes, and conventionally known ester oils, etc., are H
Since it has almost no compatibility with non-chlorine CFCs such as FC-134a, when used in combination with HFC-134a, two-layer separation occurs at room temperature, and the most important oil return in the refrigeration system deteriorates. The refrigeration efficiency is lowered or the lubricity is poor, and various practical problems such as seizure of the compressor occur, and the compressor cannot be used. Polyglycols are also known as refrigerating machine oils having a high viscosity index. For example, JP-B-57-42119 and JP-B-61.
-52880, JP-A-57-51795, and the like. However, in the polyglycol oil specifically disclosed in these prior arts, HFC-1 is still used.
The same problem as described above occurs due to insufficient compatibility with 34a, making it unpractical.

Further, US Pat. No. 4,755,316 discloses a polyglycol type refrigerating machine oil compatible with HFC-134a. Further, the present inventors have proposed that HF
A polyglycol-based refrigerating machine oil having much better compatibility with C-134a than conventionally known refrigerating machine oils has been previously developed and has already been filed (JP-A-1-256594, JP-A-1-256594). No. 271491). However, it has been found that the polyglycol-based oil has a problem that the solubility of water is high and the electric insulation is poor.

[0007] On the other hand, refrigerating machine oil used for compressors such as household refrigerators requires high electrical insulation. Among known refrigerating machine oils, those having the highest insulating properties are alkylbenzenes and mineral oils, but as described above, alkylbenzenes and mineral oils have almost no compatibility with non-chlorinated chlorofluorocarbons such as HFC-134a. Therefore, a refrigerating machine oil having both high compatibility with non-chlorinated chlorofluorocarbons such as HFC-134a and high insulating properties has not yet appeared.

The inventors of the present invention have conducted extensive research to develop refrigerating machine oils that can meet the above-mentioned requirements, and as a result, ester having a specific structure, polyalkylene glycol having a specific structure, or pentaerythritol ester having a specific structure. It was found that the mixed oils of the class are excellent in compatibility with non-chlorine CFCs such as HFC-134a and have high electric insulation, and further have excellent lubricating properties, and have completed the present invention. It was

[0009]

DISCLOSURE OF THE INVENTION The present invention relates to an HFC-13 comprising an ester having a specific structure and a mixed oil of a polyalkylene glycol having a specific structure or a pentaerythritol ester having a specific structure.
It is an object of the present invention to provide a non-chlorinated fluorocarbon refrigerant lubricating oil having excellent compatibility with non-chlorinated fluorocarbons such as 4a and having high electric insulation.

[0010]

That is, the present invention is
(I) General formula

[0011]

[Chemical 9] [Wherein X is -OR ₃ or

[0012]

[Chemical 10] A group represented by Y is

[0013]

[Chemical 11] Or

[0014]

[Chemical 12] And R ₁ and R ₇ are divalent hydrocarbon groups having 1 to 8 carbon atoms, R ₂ and R ₄ are divalent saturated hydrocarbon groups having 2 to 16 carbon atoms, and R ₃ and R ₈ each represent an alkyl group having 1 to 15 carbon atoms, R ₅ and R ₆ each represent an alkyl group having 1 to 14 carbon atoms, and l and m are 0 or 1 and n is an integer of 0 to 30. And an ester represented by the formula (II)

[0015]

[Chemical 13] [Wherein R ₉ and R ₁₀ represent hydrogen or an alkyl group having 1 to 18 carbon atoms, R ₁₁ represents an alkylene group having 2 to 4 carbon atoms, and a represents an integer of 5 to 70] Polyoxyalkylene glycol or its ether, general formula

[0016]

Embedded image [Wherein, R _{12 to} R ₁₄ represent hydrogen or an alkyl group having 1 to 18 carbon atoms, R _{15 to} R ₁₇ 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
General formula

[0017]

[Chemical 15] [In the formula, R _{18 to} R ₂₁ are linear alkyl groups having 3 to 11 carbon atoms, branched alkyl groups having 3 to 15 carbon atoms and 6 to 6 carbon atoms.
Pentaerythritol ester represented by the general formula: embedded image wherein the proportion of linear alkyl groups is 60% or less of the total alkyl groups, and e represents an integer of 1 to 3.

[0018]

Embedded image [Wherein, R _{22 to} R _{27 each} represent an alkyl group having 3 to 15 carbon atoms;
₂₈ represents a divalent hydrocarbon group having 1 to 8 carbon atoms and f represents an integer of 1 to 5], and at least one oil selected from the group consisting of pentaerythritol dicarboxylic acid ester, The present invention provides a refrigerating machine oil for a non-chlorine CFC refrigerant, which is characterized by using the mixed oil of 1. as a base oil.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The contents of the present invention will be described in more detail below.

The component [I] of the refrigerating machine oil of the present invention has a general formula

[0021]

[Chemical 17] Is an ester represented by

In the above formula, X is -OR ₃ or

[0023]

Embedded image A group represented by Y is

[0024]

[Chemical 19] Or

[0025]

Embedded image And a group represented by

R ₁ and R ₇ are divalent hydrocarbon groups having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, and R ₂ and R ₄ are divalent hydrocarbon groups having 2 to 16 carbon atoms, preferably 2 to 9 carbon atoms. Saturated hydrocarbon group, R ₃ and R ₈ have 1 to 15 carbon atoms, preferably 1 to
12 alkyl groups, R ₅ and R _{6 each} have 1 to 14 carbon atoms;
Preferably, each represents 1 to 11 alkyl groups. Furthermore, l and m are 0 or 1 and n is 0 to 1.
30 and preferably an integer of 1 to 30, respectively. It is not preferable to use an ester that does not satisfy the above conditions as the component [I] because the compatibility with the hydrogen-containing fluorocarbon is poor.

Specific examples of R ₁ and R ₇ include methylene, ethylene, propylene, trimethylene, butylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, and octamethylene. , Phenylene group, other unsaturated groups and the like are exemplified,
As R ₂ and R ₄ , in addition to the above alkylene group (excluding the methylene group), a nonamethylene group, a decamethylene group,
Examples include an undecamethylene group, a dodecamethylene group, a tridecamethylene group, a tetradecamethylene group, a pentadecamethylene group, a hexadecamethylene group, and a cyclohexylene group. Further, as R ₅ and R ₆ , specifically, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group,
Decyl group, undecyl group, dodecyl group, tridecyl group,
A straight-chain or branched alkyl group such as a tetradecyl group is exemplified. As R ₃ and R ₈ , a straight-chain or branched alkyl group such as a pentadecyl group is exemplified in addition to the above-mentioned alkyl groups.

In the present invention, the above ester may be used alone or as a mixture of two or more kinds as the component [I]. The molecular weight of the ester of the component [I] in the present invention is not particularly limited, but the number average molecular weight is preferably from the viewpoint of further improving the sealing property of the compressor.
Those having a number average molecular weight of 300 to 2000 are more preferably used. Further, the kinematic viscosity of the ester of the component [I] in the present invention is 2 to 150 cSt at 100 ° C., preferably 5 to 1 cSt.
00cSt is desirable.

The method for producing the ester of the component [I] in the present invention is arbitrary, but for example, (a) a diol containing no ether bond in the branch, (b) a dicarboxylic acid, and (c) a monohydric alcohol and A mixture can be manufactured at once by carrying out the esterification reaction of the / or monohydric alcohol. It can also be produced by reacting (a) with the monohydric carboxylic acid of (c) or by reacting (b) with the monohydric alcohol of (c).

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, heptaglycol are used. Methylene 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-pentanediol, 2,4
Alkylene glycols such as -pentanediol, 2-methyl-2,4-pentanediol, 2-methyl-1,6-hexane, 1,4-cyclohexanedimethanol, 2,2-bis (4-hydroxycyclohexyl) propane Etc. are exemplified.

As (b), a dicarboxylic acid having 2 to 10 carbon atoms is used. Specifically, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid,
Subaruic 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 -Unsaturated aliphatic dicarboxylic acids such as methyl glutaric acid, 3-methyl glutaric acid, 3,3-dimethyl glutaric acid, and 3-methyl adipic acid, and unsaturated acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid; Examples thereof include aromatic dicarboxylic acids such as aliphatic dicarboxylic acids, phthalic acid, isophthalic acid, and terephthalic acid.

Further, (c) monovalent carboxylic acids having 2 to 15 carbon atoms are used, and specific examples thereof include acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, and nonane acid. Acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, 3-methylbutanoic acid, 2-methylbutanoic acid, 2-ethylhexanoic acid, 2,4-dimethylpentanoic acid, 3,3,5- Examples include trimethylhexanoic acid and benzoic acid.

As the monohydric alcohol (c), one having 1 to 15 carbon atoms is used. Specifically, methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, Undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, isopropanol, isobutanol, 2-methyl-1-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-trimethyl-1-pentanol, 2-ethyl-4-
Methyl-1-pentanol, 2-ethyl-1-hexanol and the like are exemplified.

The products obtained from the above-mentioned raw materials may be purified to remove by-products and unreacted products. However, a small amount of by-products and unreacted products may be removed from the refrigerator oil of the present invention. As long as they do not adversely affect good performance, they do not interfere.

The component [II] of the refrigerating machine oil of the present invention has the general formula

[0036]

[Chemical 21] [Wherein R ₉ and R ₁₀ represent hydrogen or an alkyl group having 1 to 18 carbon atoms, R ₁₁ represents an alkylene group having 2 to 4 carbon atoms, and a represents an integer of 5 to 70] Polyoxyalkylene glycol or its ether, general formula

[0037]

[Chemical formula 22] [Wherein, R _{12 to} R ₁₄ represent hydrogen or an alkyl group having 1 to 18 carbon atoms, R _{15 to} R ₁₇ represent an alkylene group having 2 to 4 carbon atoms, and b to d represent an integer of 5 to 70. Polyoxyalkylene glycol glycerol ether represented by the general formula:

[0038]

[Chemical formula 23] [In the formula, R _{18 to} R ₂₁ are linear alkyl groups having 3 to 11 carbon atoms, branched alkyl groups having 3 to 15 carbon atoms and 6 to 6 carbon atoms.
A group selected from the group consisting of 12 cycloalkyl groups, the proportion of straight-chain alkyl groups being 60% or less based on the total alkyl groups, and e represents an integer of 1 to 3], a pentaerythritol ester represented by the general formula:

[0039]

[Chemical formula 24] [Wherein, R _{22 to} R _{27 each} represent an alkyl group having 3 to 15 carbon atoms;
₂₈ represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and f represents an integer of 1 to 5], wherein at least one oil selected from the group consisting of pentaerythritol dicarboxylic acid esters is there.

In the present invention, these oils may be used alone or in combination of several kinds as the component [II].

Oils such as paraffinic and naphthenic mineral oils, poly-α-olefins, alkylbenzenes and the like may be mixed, but in this case, the compatibility with the non-chlorinated fluorocarbon solvent is reduced.

The amount of the base oil is not particularly limited as long as the excellent performance of the refrigerating machine oil of the present invention is not impaired. It is usually blended so as to be more than 50% by weight, preferably 70% by weight or more based on the total amount of the machine oil.

In the refrigerating machine oil composition of the present invention, in order to further improve its wear resistance and load resistance, phosphate ester, acidic phosphate ester, amine salt of acidic phosphate ester, chlorinated phosphate ester and At least one phosphorus compound selected from the group consisting of phosphites can be blended. These phosphorus compounds are esters of phosphoric acid or phosphorous acid with alkanols, polyether type alcohols, or derivatives thereof. Specific examples of the phosphoric acid ester include tributyl phosphate, triphenyl phosphate, tricresyl phosphate and the like. Examples of the acidic phosphate include ditetradecyl acid phosphate, dipentadecyl acid phosphate, dihexadecyl acid phosphate, diheptadecyl acid phosphate, dioctadecyl acid phosphate, and the like. Examples of the acidic phosphate ester amine salt include the acidic phosphate esters methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, and the like. Dipentylamine, dihexylamine, diheptylamine, dioctylamine, trimethylamine, triethylamine,
Examples thereof include salts with amines such as tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine and trioctylamine. Examples of chlorinated phosphates include tris-dichloropropyl phosphate, tris-chloroethyl phosphate, polyoxyalkylene bis [di (chloroalkyl)]
Phosphate, tris-chlorophenyl phosphate and the like. Examples of the phosphite include dibutyl phosphite, tributyl phosphite, dipentyl phosphite, tripentyl phosphite, dihexyl phosphite, trihexyl phosphite, diheptyl phosphite, triheptyl phosphite, dioctyl phosphite, and trioctyl phosphite. Phyto, dinonyl phosphite, didecyl phosphite, diundecyl phosphite, triundecyl phosphite, didodecyl phosphite, tridodecyl phosphite, diphenyl phosphite, triphenyl phosphite, dicresyl phosphite, tricresyl Phosphite and the like. Also, a mixture of these can be used. When these phosphorus compounds are blended, it is desirable to contain them in a proportion of 0.1 to 5.0% by weight, preferably 0.2 to 2.0% by weight, based on the total amount of the refrigerating machine oil.

In the refrigerating machine oil of the present invention, in order to further improve its stability, it is selected from the group consisting of a phenyl glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, an epoxidized fatty acid monoester and an epoxidized vegetable oil. At least one epoxy compound can be blended. Examples of the phenylglycidyl ether type epoxy compound referred to here include phenylglycidyl ether and alkylphenylglycidyl ether. The alkylphenyl glycidyl ether as used herein has 1 to 3 alkyl groups having 1 to 13 carbon atoms, and particularly 4 to 10 carbon atoms.
Having one alkyl group such as butyl phenyl glycidyl ether, benzyl phenyl glycidyl ether, hexyl phenyl glycidyl ether, heptyl phenyl glycidyl ether, octyl phenyl glycidyl ether, nonyl phenyl glycidyl ether and decyl phenyl glycidyl ether are preferable. Examples of the glycidyl ester type epoxy compound include phenyl glycidyl ester, alkyl glycidyl ester, alkenyl glycidyl ester and the like, and preferable examples include glycidyl benzoate, glycidyl acrylate, glycidyl methacrylate and the like.

Examples of the epoxidized fatty acid monoester include esters of an epoxidized fatty acid having 12 to 20 carbon atoms and an alcohol or phenol or alkylphenol having 1 to 8 carbon atoms. Particularly, butyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl, phenyl and butylphenyl esters of epoxystearic acid are preferably used.

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

Preferred among these epoxy compounds are phenylglycidyl ether type epoxy compounds and epoxidized fatty acid monoesters. Among them, phenyl glycidyl ether type epoxy compounds are more preferable, and phenyl glycidyl ether, butyl phenyl glycidyl ether and mixtures thereof are particularly preferable.

When blending these epoxy compounds,
It is desirable that the content be 0.1 to 5.0% by weight, preferably 0.2 to 2.0% by weight, based on the total amount of the refrigerating machine oil.

Of course, the phosphorus compound and the epoxy compound may be used in combination.

Further, for the refrigerating machine oil in the present invention,
In order to further improve its performance, conventionally known refrigerator oil additives such as phenols such as di-tert-butyl-p-cresol and bisphenol A, phenyl-α-naphthylamine, N, N- Di (2-
Amine antioxidants such as naphthyl) -p-phenylenediamine; antiwear agents such as zinc dithiophosphate; extreme pressure agents such as chlorinated paraffins and sulfur compounds; oily agents such as fatty acids;
Additives such as silicone-based antifoaming agents and metal deactivators such as benzotriazole may be used alone or in combination of several kinds. The total amount of these additives is usually 10% by weight or less based on the total amount of the refrigerating machine oil,
It is preferably 5% by weight or less.

The refrigerating machine oil of the present invention only needs to have a kinematic viscosity and a pour point that are generally used as the refrigerating machine oil. However, in order to prevent the refrigerating machine oil from solidifying at low temperatures, the pour point must be-. It is desirably 10 ° C or lower, preferably -20 ° C to -80 ° C. Further, in order to maintain the hermeticity with the compressor, the kinematic viscosity at 100 ° C. is preferably 2 cSt or more, preferably 3 cSt or more. Considering the fluidity at low temperature and the efficiency of heat exchange in the vaporizer, 100 ° C.
Has a kinematic viscosity of 150 cSt or less, preferably 100
It is preferably cSt or less.

The refrigerating machine oil of the present invention is significantly superior in compatibility with chlorine-free fluorocarbons as compared with conventionally known refrigerating machine oils. Specific examples of non-chlorinated fluorocarbons include 1,1,2,2
2-tetrafluoroethane (HFC-134), 1,
1,1,2-tetrafluoroethane (HFC-134
a), 1,1-difluoroethane (HFC-152
a), trifluoromethane (HFC-23) and the like are exemplified, and preferred is HFC-134a.

Further, the refrigerating machine oil of the present invention is excellent not only in compatibility with non-chlorine flon and electric insulation but also in high lubricity and low hygroscopicity.

The lubricating oil for a refrigerator according to the present invention can be used as a cooling device for an air conditioner having a reciprocating or rotary compressor, a dehumidifier, a refrigerator, a freezer, a refrigerated warehouse, a vending machine, a showcase, a chemical plant and the like. Etc., but can also be preferably used for those having a centrifugal compressor.

[0055]

EXAMPLES The contents of the present invention will be described more specifically below with reference to examples.

Base oils 1 to 12 The base oils used in the examples and comparative examples are shown below.

Base oil 1: a complex ester of 3-methyl-1,5-pentanediol, adipic acid and 3,5,5-trimethylhexanoic acid having an average molecular weight of about 70
0.

[0058]

[Chemical 25] Base oil 2: complex ester of 3-methyl-1,5-pentanediol, adipic acid and 2-ethyl-1-hexanol with an average molecular weight of about 520.

[0059]

[Chemical formula 26] Base oil 3: polypropylene glycol monomethyl ether

[0060]

[Chemical 27] Base oil 4: glycerin-propylene oxide adduct terminal trimethyl ether

[0061]

[Chemical 28] Base oil 5: pentaerythritol / iC ₇ acid, iC ₈ acid ester

[0062]

[Chemical 29] Base oil 6: Complex ester of pentaerythritol / 2-ethylhexanoic acid / adipic acid

[0063]

Embedded image Base oil 7: naphthenic mineral oil.

Base oil 8: branched-chain alkylbenzene (average molecular weight: about 300).

Base oil 9: Polyoxypropylene glycol monobutyl ether (average molecular weight about 500).

Base oil 10: polyoxypropylene glycol monobutyl ether (average molecular weight about 1000).

Base oil 11: polyoxypropylene glycol (average molecular weight 700).

Base oil 12: Polyoxypropylene glycol (average molecular weight about 2000).

Epoxy compounds 1 to 3 Epoxy compound 1: phenyl glycidyl ether Epoxy compound 2: p-s-butylphenyl glycidyl ether Epoxy compound 3: 1,1-dimethyloctanoic acid glycidyl ester Phosphorus compound 1 Phosphorus compound 1: Tricresyl Phosphate Examples 1 to 11 and Comparative Examples 1 to 6 Refrigerating machine oils according to the present invention were prepared with the compositions shown in Table 1, and the solubility with HFC-134a, insulation properties, Falex wear test, and moisture absorption were evaluated for performance evaluation. And the shield tube test were evaluated. For comparison, Table 1 also shows the test results of mineral oil, alkylbenzene, polypropylene glycol monoalkyl ether conventionally used for refrigerating machine oil, and polyalkylene glycol disclosed in US Pat. No. 4,755,316. To do. (Solubility with HFC-134a) Inner diameter 6 mm, length 22
Into a 0 mm glass tube, 0.2 g of the sample oils of Examples and Comparative Examples was collected, and 2 g of refrigerant (HFC-134a) was further collected.
And collect the glass tube. This glass tube is placed in a low temperature tank or a high temperature tank having a predetermined temperature, and it is observed whether the refrigerant and the sample oil are mutually dissolved, separated or clouded. (Insulation characteristics) The volume resistance of the sample oil was measured according to JIS C 2101. The test was performed at 25 ° C. (FALEX wear test) In accordance with ASTM D 2670, the sample oil temperature was 100 ° C., a running-in operation was carried out for 1 minute at a load of 150 lbs, and then it was operated for 2 hours under a load of 250 lbs to measure the wear amount of the test journal. Was done. (Hygroscopicity) Take 30 g of sample oil in a 300 ml beaker,
After leaving still in a thermo-hygrostat maintained at 60 ° C. and 30% humidity for 7 days, the water content was measured by the Karl Fischer method. (Shield tube test) 50 g of sample oil was put into a 100 ml beaker, and was left still for 168 hours in a thermo-hygrostat at a relative humidity of 80% and a temperature of 25 ° C. This sample oil and HFC134a
The equivalent mixture of was mixed with a catalyst of iron, copper and aluminum in a glass tube, and the change in oil after heating at 175 ° C. for 168 hours was observed and evaluated.

[0070]

[Table 1] As shown in Examples 1 to 11 in Table 1, the refrigerating machine oil according to the present invention was higher in HFC-1 than the refrigerating machine oils shown in Comparative Examples 1 and 2.
The solubility of the refrigerant in 34a is very excellent.

As shown in Comparative Examples 3 to 6, polyalkylene glycols are excellent in refrigerant solubility, but have poor insulation properties, and cannot be used for hermetic compressors.

Also, in the abrasion test by Falex, it is understood that Examples 1 to 11 are equivalent to or more than Comparative Examples 3 and 6.

The moisture absorption properties of the refrigerating machine oils of Examples 1 to 11 are lower than those of the alkylene glycols of Comparative Examples 3 to 6, and are excellent.

Further, as shown in Examples 8 to 11, the refrigerating machine oil to which the epoxy compound is added has very excellent stability in the shield tube test.

Further, as shown in Examples 10 to 11,
Refrigerating machine oil to which a phosphorus compound is added is very excellent in wear resistance.

[0076]

As is apparent from the above description and the examples, the refrigerating machine oil of the present invention is suitable for use in a non-chlorinated fluorocarbon refrigerating machine, has excellent electrical insulation properties and abrasion resistance. Refrigeration oil excellent in non-hygroscopicity.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C10M 169/04 C10M 169/04 // (C10M 169/04 105: 38 105: 42 105: 18 107: 34 137 : 02 137: 04 129: 66 129: 18) C10N 40:30

Claims (4)

[Claims] 1. (I) General formula: Wherein X is —OR ₃ or A group represented by the formula: Y is Or [Chemical 4] And R ₁ and R ₇ are divalent hydrocarbon groups having 1 to 8 carbon atoms, R ₂ and R ₄ are divalent saturated hydrocarbon groups having 2 to 16 carbon atoms, and R ₃ and R ₈ each represent an alkyl group having 1 to 15 carbon atoms, R ₅ and R ₆ each represent an alkyl group having 1 to 14 carbon atoms, and l and m are 0 or 1 and n is an integer of 0 to 30. And an ester represented by the general formula (II) [Wherein R ₉ and R ₁₀ represent hydrogen or an alkyl group having 1 to 18 carbon atoms, R ₁₁ 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, represented by the general formula: Wherein, R ₁₂ to R ₁₄ represents hydrogen or an alkyl group having 1 to 18 carbon atoms, R ₁₅ to R ₁₇ represents an alkylene group having 2 to 4 carbon atoms, an integer of b~d 5-7 Represented by the formula], a polyoxyalkylene glycol glycerol ether represented by the general formula: [In the formula, R _{18 to} R ₂₁ are linear alkyl groups having 3 to 11 carbon atoms, branched alkyl groups having 3 to 15 carbon atoms and 6 to 6 carbon atoms.
Pentaerythritol ester represented by the general formula: embedded image wherein the proportion of linear alkyl groups is 60% or less based on all alkyl groups, and e is an integer of 1 to 3 Embedded image [Wherein, R _{22 to} R _{27 each} represent an alkyl group having 3 to 15 carbon atoms;
₂₈ represents a divalent hydrocarbon group having 1 to 8 carbon atoms, and f represents an integer of 1 to 5], and at least one oil selected from the group consisting of pentaerythritol dicarboxylic acid ester represented by the formula: A refrigerating machine oil for a non-chlorine CFC refrigerant, which is characterized by using a mixed oil of the above as a base oil. 2. The refrigerating machine oil for chlorine-free fluorocarbon refrigerant according to claim 1, wherein (I) the ester is blended in an amount of more than 50% by weight with respect to the refrigerating machine oil. 3. A phosphoric acid ester, based on the total amount of the refrigerating machine oil,
Acid phosphate, amine salt of acid phosphate,
At least one phosphorus compound selected from the group consisting of chlorinated phosphates and phosphites
The refrigerating machine oil for a non-chlorinated CFC refrigerant according to claim 1 or 2, which contains 5.0% by weight as an essential component. 4. At least one epoxy compound 0.1 to 5 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. The refrigerating machine oil for chlorine-free fluorocarbon refrigerant according to any one of claims 1 to 3, which contains 0.0% by weight as an essential component.