JPH0578689A - Composition of hydraulic fluid for refrigerating machine - Google Patents

Abstract

PURPOSE:To provide the subject composition excellent in compatibility, Iubricity, thermal stability, electrical insulation, etc., comprising a hydrofluorocarbon and a refrigerating machine oil prepared by incorporating a specific ester with a specified amount of a triaryl phosphate, etc. CONSTITUTION:The objective composition comprising (A) a refrigerating machine oil prepared by incorporating (1) 100 pts.wt. of an ester obtained from 1-6 primary hydroxyl groups-bearing aliphatic polyhydric alcohol, 2-9C saturated aliphatic monocarboxylic acid (derivative) and 2-10C saturated aliphatic dicarboxylic acid (derivative) with (2) at least one kind of compound selected from 0.1-5.0 pts.wt. of a triaryl phosphate or triaryl phosphite, 0.001-0.1 pt.wt. of benzotriazole (derivative), 0.05-20 pts.wt. of an epoxy group-contg. compound, and 0.001-2.0 pts.wt. of a metal-deactivator with chelating ability and (B) a hydrofluorocarbon such as 1,1,1,2-tetrafluorethane.

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 a refrigerator, and more particularly to a working fluid composition for a compression refrigerator for an electric refrigerator or 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 is being banned in the future. Therefore, as an alternative to this CFC12, hydrofluorocarbons that do not destroy the ozone layer, such as 1,1,1,2
-Tetrafluoroethane (HFC134a) has been developed.

However, hydrofluorocarbons are CF
Since the polarity is higher than that of C12, if a lubricating oil such as naphthenic mineral oil, poly α-olefin, alkylbenzene, etc., which has been generally used as a refrigerating machine oil, is used, the compatibility between these lubricating oil and hydrofluorocarbon is poor. , Two-phase separation occurs at low temperature. When two-layer separation occurs, oil return deteriorates and 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 the lubricity, in CFC12, it is partly decomposed to generate hydrogen chloride, and this hydrogen chloride reacts with the friction surface to form a chloride film to improve lubricity. was there. However, since such effects cannot be expected for hydrofluorocarbons containing no chlorine atom, refrigerating machine oils used with hydrofluorocarbons are required to have better lubricity than conventional ones.

Further, the refrigerating machine oil used together with the hydrofluorocarbon must have good thermal stability in the presence of the hydrofluorocarbon. Further, in addition to this, since the compression refrigerator of the electric refrigerator has an organic material used for a motor such as an insulating material and an enameled wire, the working fluid composed of hydrofluorocarbon and refrigerating machine oil contains these organic materials. It is necessary that the material is not adversely affected and that the electrical insulation is good.

Hydrofluorocarbons, for example 1,1,
Refrigerating machine oils that can be used together with 1,2-tetrafluoroethane (HFC134a) include US Pat. No. 4,755,316, JP-A-1-198694, and JP-A-1-256594.
Japanese Unexamined Patent Publication Nos. 1-259093, 1-259094, and 1-
259095, JP-A-2-84491, JP-A-2-102296,
JP-A-2-129294, JP-A-2-132176, JP-A-2-
132177, JP-A-2-132178, JP-A-2-132179,
JP-A-2-173195, JP-A2-180986, JP-A-2-
180987, JP-A-2-182780, JP-A-2-242823,
JP-A-2-242888, JP-A-2-258896, JP-A-2-
269195, JP-A-2-272097, JP-A-2-281098 and the like disclose polyether compounds.

Since the polyether compound has a higher polarity than the naphthenic mineral oil, the compatibility with HFC134a at low temperature is certainly good. However, US Pat.
As described in the specification, the polyether compound, on the contrary, has a problem of causing two-layer separation when the temperature rises, and 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 of HFC134a is deteriorated, and the PET film or the like which is an organic material is hydrolyzed.

Further, in terms of lubricity, the polyether compound cannot be said to be sufficiently good, and the hydrofluorocarbon type refrigerant-polyether compound system such as HFC134a is inferior to the conventional CFC12-naphthene type mineral oil system. ing.

Ester compounds have been developed in order to improve the problems of the polyether compounds such as electric insulation, hygroscopicity and lubricity. The ester compound has excellent compatibility with hydrofluorocarbon and also has excellent thermal stability in the presence of hydrofluorocarbon. Further, compared with the polyether compound, it has an extremely excellent electric insulating property, a considerably low hygroscopic property, and an excellent lubricity.

However, the conventional working fluid CF
Compared to C12-mineral oil type, hydrofluorocarbon-ester oil type has higher polarities in both freon and oil and tends to contain water. Although the refrigerator is equipped with a dryer that removes water by molecular sieves, the ester may be hydrolyzed by the remaining water that cannot be sufficiently removed to form a carboxylic acid. It is feared that the generated carboxylic acid corrodes the metal and causes wear and copper plating.

As described above, in the prior art, compositions such as hydrofluorocarbon and oil used in refrigerators for electric refrigerators and the like have performances such as compatibility, lubricity, thermal stability, and electrical insulation. The current situation is that nothing satisfying the above has been found. Therefore, an object of the present invention is to provide a composition for a working fluid of a refrigerator, which has excellent properties such as compatibility, lubricity, thermal stability, and electrical insulation.

[0013]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventor has found that an ester compound to which a certain compound is added can achieve the above object. The present invention has been completed and the present invention has been completed.

That is, the present invention relates to 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. Acid or its derivative, and (c) 2 carbon atoms
~ 10 straight chain or branched chain saturated aliphatic dicarboxylic acid or its derivative, and B) (a) an aliphatic polyhydric alcohol having 1 to 6 primary hydroxy groups, and (d) carbon One or more esters selected from among straight-chain or branched-chain saturated aliphatic monohydric alcohols having a number of 1 to 10 and (e) a polyvalent carboxylic acid having a carbon number of 2 to 10 or a derivative thereof. In addition, 0.1 to 5.0 parts by weight of triaryl phosphate and / or triaryl phosphite, 1001 parts by weight of the ester, benzotriazole and / or benzotriazole derivative 0.001 to 0.
Refrigerating machine oil prepared by blending 1 part by weight, 0.05 to 2.0 parts by weight of a compound having an epoxy group, and 0.001 to 2.0 parts by weight of a metal deactivator having a chelating ability, and hydrofluorocarbon. The present invention relates to a composition for a working fluid of a refrigerator containing

(A) used for producing the ester of the present invention
The aliphatic polyhydric alcohol as a component is one in which 1 to 6 of the hydroxy groups are primary hydroxy groups,
Specifically, neopentyl glycol, 2,2-diethyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, trimethylolethane, trimethylolpropane, trimethylolnonane , Hindered alcohols such as pentaerythritol and dipentaerythritol, or ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,4 -Butanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, glycerin, diglycerin, polyglycerin, 1,2,4-butanetriol, 1,2,6-hexanetriol, sorbitol and Multivalent alcohol such as mannitol There is Le. The number of carbon atoms of these aliphatic polyhydric alcohols is 2-30, preferably 2-20, more preferably 2-10. When the number of carbon atoms is more than 30, the viscosity becomes high and the compatibility with the hydrofluorocarbon type refrigerant becomes poor. The number of hydroxy groups of these aliphatic polyhydric alcohols is 2 to 6, preferably 2 to 3. If there are more than 6 hydroxy groups, the viscosity will be too high. Hindered alcohol is particularly excellent in terms of heat resistance.

The saturated aliphatic monocarboxylic acid as the component (b) is
The number of carbon atoms is 2 to 9, more preferably 5 to
It is 9. Specific examples of these monocarboxylic acids or derivatives thereof 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-butyl Acetic acid, enanthate,
2,2-dimethylpentanoic acid, 2-ethylpentanoic acid, 3
-Ethylpentanoic acid, 2-methylhexanoic acid, 3-methylhexanoic acid, 4-methylhexanoic acid, 5-methylhexanoic 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, pelargonic acid, 2,
2-dimethylheptanoic acid, 3,5,5-trimethylhexanoic acid, 2-methyloctanoic acid, 2-ethylheptanoic acid, 3
-Methyl octanoic acid, or their methyl esters, ethyl esters, acid anhydrides and the like. From the viewpoint of compatibility with hydrofluorocarbon type refrigerants and hydrolysis resistance, branched saturated fatty acids are preferable to linear saturated fatty acids. 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 less than 2, corrosiveness to metals may increase. Further, those having an unsaturated bond are not preferable in terms of heat resistance.

The saturated aliphatic dicarboxylic acid as the component (c) 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 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-methyl glutaric acid, butyl malonic acid, diethyl malonic acid, 2,2-dimethyl glutaric acid, 2,4-dimethyl glutaric acid, 3,3-dimethyl glutaric acid, 2-ethyl-2-
Methylsuccinic acid, 3-methyladipic acid, pimelic acid,
Examples thereof include suberic acid, 2,2-dimethyladipic acid, azelaic acid, sebacic acid, their methyl esters, ethyl esters, and acid anhydrides.

The saturated aliphatic monohydric alcohol as the component (d) is
The number of carbon atoms is 1 to 10, more preferably 5 to
It is 9. 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,
Propanol, isopropanol, butanol, 1-methylpropanol, 2-methylpropanol, t-butanol, pentanol, 2-methylbutanol, 3-methylbutanol, 1-ethylpropanol, hexanol, 2-methylpentanol, 2-ethylbutanol ,
2,3-dimethylbutanol, heptanol, 2-methylhexanol, 3-methylhexanol, 5-methylhexanol, octanol, 2-ethylhexanol,
2-Methylheptanol, 3,5-dimethylhexanol, nonanol, 3,5,5-trimethylhexanol, decyl alcohol, 2,4,6-trimethylheptanol 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), 1,2,3-tricarboxypropane, β-methyltricarboxylic acid, 1,
Linear or branched saturated aliphatic polycarboxylic acids such as 3,6-tricarboxyhexane, aromatic polycarboxylic acids such as phthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid, or their methyl groups. Examples thereof include esters, ethyl esters and acid anhydrides.

The ester used in the present invention includes components (a) to (c) for the ester of A) and (a), (d),
It is obtained by reacting the component (e). The compatibility of the ester of the present invention with a hydrofluorocarbon-based refrigerant at low temperatures generally becomes worse as the viscosity increases. Therefore, a preferable ester 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. From the viewpoint of compatibility with hydrofluorocarbon type refrigerants, the saponification value of the ester of the present invention is preferably 330 mgKOH / g or more, 350 mgKOH / g or more.
OH / g or more is more preferable. If it is less than this range, the compatibility with the hydrofluorocarbon type refrigerant becomes poor. From the viewpoint of lubricity, the higher the hydroxyl value of the ester of the present invention, the better, and 5 mgKOH / g or more is preferable. However, as the hydroxyl value increases, the hygroscopicity increases, so 50 mgKOH / g
The following are preferred. More preferably 5 mg KOH / g or more 30 m
It is less than or equal to gKOH / g.

In the ester of the present invention, from the viewpoints of corrosion resistance to metals and hydrolysis stability, (a) a polyhydric alcohol, (b) an aliphatic monocarboxylic acid or a derivative thereof, which is a raw material of the ester, (c) The aliphatic dicarboxylic acid or its derivative, the (d) monohydric alcohol, and the (e) polyvalent carboxylic acid or its derivative are particularly preferable if any of them has a branched structure.

In the ester of A) of the present invention, (f)
Among components (a), an aliphatic divalent alcohol having 1 to 2 primary hydroxy groups, and (b) a linear or branched saturated aliphatic monocarboxylic acid having 2 to 9 carbon atoms or a derivative thereof. ,
(g) Among components (c), an ester obtained from a straight-chain or branched-chain saturated aliphatic dicarboxylic acid having 2 to 8 carbon atoms or a derivative thereof, or among the esters of B) of the present invention, (f)
Among the components (a), an aliphatic dihydric alcohol having 1 to 2 primary hydroxy groups, a saturated aliphatic monohydric alcohol (d), and (g) (e) the carbon number An ester obtained from a linear or branched saturated aliphatic dicarboxylic acid having 2 to 8 or a derivative thereof is particularly excellent in compatibility with a hydrofluorocarbon refrigerant at low temperature and lubricity.

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, Examples thereof include dihydric alcohols such as 4-butanediol, 1,6-hexanediol and 2-ethyl-1,3-hexanediol, and hindered alcohols represented by the following formula (I). Specific examples of the hindered alcohol include neopentyl glycol, 2,2-diethyl-1,3-propanediol and 2-
Examples include n-butyl-2-ethyl-1,3-propanediol. The number of carbon atoms of these aliphatic dihydric alcohols is 2-30, preferably 2-20, more preferably 2-10.
Is. From the viewpoint of heat resistance, the hindered alcohol represented by the following formula (I) is particularly excellent.

[0024]

[Chemical 1]

(In the formula, R ₁ and R ₂ each represent an alkyl group having 1 to 6 carbon atoms.) Specific examples of the component (g) include oxalic acid, malonic acid, methylmalonic acid and succinic acid. 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-dimethyl glutaric acid, 2-ethyl-2-methyl succinic acid, 3-methyl adipic acid, pimelic acid, suberic acid, 2,2-dimethyl Adipic acid may be mentioned.

Further, in consideration of compatibility with a hydrofluorocarbon type refrigerant at low temperature, lubricity, heat resistance, hydrolysis resistance and the like, (a) neopentyl glycol or 2,
Most preferred are the esters obtained from 2-diethyl-1,3-propanediol, (b) 2-methylhexanoic acid and (g) adipic acid or glutaric acid.

The ester of A) used in the present invention includes at least one polyhydric alcohol of (a) described above and the monocarboxylic acid of (b) described above or a lower alkyl ester or acid anhydride thereof. Etc. and one or more of the above-mentioned dicarboxylic acid of (c) or its lower alkyl ester, acid anhydride, etc., can be obtained by a usual esterification reaction or transesterification reaction. At this time, 0.9 mol or less of dicarboxylic acid or its derivative is reacted with 1 mol of polyhydric alcohol. It is more preferably 0.8 mol or less. If more than 0.9 mol is reacted, the viscosity increases. The number of moles of monocarboxylic acid to 1 mole of polyhydric alcohol is determined by the number of moles of dicarboxylic acid described above and the hydroxyl value of the ester to be obtained.

The ester of B) used in the present invention is one or more polyhydric alcohols of the above-mentioned (a) and one or more monohydric alcohols of the above-mentioned (d). (e)
It can be obtained by a conventional esterification reaction or transesterification reaction with at least one of the polyvalent carboxylic acid or its lower alkyl ester, an acid anhydride and the like. At this time, 1.5 mol or less of polyhydric alcohol is reacted with 1 mol of polyvalent carboxylic acid 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 monohydric alcohol to 1 mole of polyvalent carboxylic acid or its derivative is determined by the number of moles of polyhydric alcohol described above and the hydroxyl value of the ester to be obtained.

The lower the acid value of these esters is, the more preferable it is, and usually 0.1 mgKOH / g or less, particularly 0.05 mgKOH / g or less is preferable. If the acid value is greater than 0.1 mg KOH / g, the corrosiveness to metals may increase, which is not preferable. The esters A) and B) used in the present invention may be used alone or as a mixture. The ratio when mixing is A) / B) = 10
It is 0 / 0-0 / 100 (weight ratio).

The composition of ester and hydrofluorocarbon used in the present invention has high polarities of both freon and oil and easily contains water. The refrigerator is equipped with a dryer for removing water by molecular sieve. The water that cannot be sufficiently removed may hydrolyze the ester to form a carboxylic acid, which may adversely affect the carboxylic acid produced.

Therefore, water in the composition or a compound having an epoxy group is added to trap the produced carboxylic acid, or benzotriazole and / or benzotriazole is added to protect the metal surface so that the carboxylic acid does not corrode the metal. Alternatively, it is effective to add a benzotriazole derivative or to add a triaryl phosphate and / or a triaryl phosphite. The addition of triaryl phosphate and / or triaryl phosphite also has the effect of improving lubricity. Also,
In order to improve the thermal stability, it is effective to add a metal deactivator having a chelating ability. Therefore, it is necessary to add at least one of the above four additives. Particularly, it is very preferable to add a compound having an epoxy group among the above-mentioned four kinds of compounds.

Examples of the compound having an epoxy group include phenyl glycidyl ether, butyl glycidyl ether,
Glycidyl ethers such as 2-ethyl glycidyl ether, cresyl glycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether Or
Glycidyl esters such as phthalic acid diglycidyl ester, cyclohexanedicarboxylic acid diglycidyl ester, and adipic acid diglycidyl ester; epoxidized fatty acid monoesters such as epoxidized methyl stearate and epoxidized butyl stearate; and epoxidized soybean oil. ,
Examples thereof include epoxidized vegetable oils such as epoxidized linseed oil, epoxy cyclooctane, epoxy cycloheptane, alicyclic epoxy compounds such as compounds having an epoxy cyclohexyl group and compounds having an epoxy cyclopentyl group described later.

In the system of CFC12 or monochlorodifluoromethane (HCFC22) containing chlorine atom, hydrochloric acid is generated due to the decomposition of freon, and in order to trap this, phenylglycidyl ether type epoxy compound, epoxidized fatty acid monoester, epoxidized Epoxy compounds such as vegetable oils are widely added to oils such as naphthenic oil. JPA
In some cases, a compound having an epoxycycloalkyl group such as epoxycyclooctane is added to a polyether compound to prevent the deterioration of the polyether compound due to hydrochloric acid, as disclosed in Japanese Patent Publication 57-63395.

However, since the acid generated in the composition of the hydrofluorocarboxylic acid of the present invention and the ester is not a strong acid such as hydrochloric acid but a saturated aliphatic monocarboxylic acid,
Ordinary epoxy compounds as shown above are not very effective, and in the present invention, alicyclic epoxy compounds,
In particular, it is highly preferable to add a compound having an epoxycyclohexyl group and / or a compound having an epoxycyclopentyl group.

The compound having an epoxycyclohexyl group and the compound having an epoxycyclopentyl group used in the present invention have 5 to 40 carbon atoms, preferably 5 to 25 carbon atoms, and specifically, 1,2- Epoxycyclohexane, 1,2-epoxycyclopentane, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate,
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, exo-2,3-epoxynorbornane, 2- (7-oxabicyclo [4.1.0]
] Hept-3-yl) -spiro (1,3-dioxane-5,
3 '-[7] oxabicyclo [4.1.0] heptane), 4-
Epoxyethyl-1,2-epoxycyclohexane, 4-
(1'-Methylepoxyethyl) -1,2-epoxy-2-
Methylcyclohexane and the like can be mentioned. In the present invention, these compounds having an epoxycyclohexyl group may be used singly or in combination of two or more, and the compounds having an epoxycyclopentyl group may be used alone or in combination of two or more. Further, a compound having an epoxycyclohexyl group and a compound having an epoxycyclopentyl group may be used in combination. The amount added is the ester used in the present invention.
0.05 to 2.0 parts by weight, preferably 100 to 100 parts by weight, preferably
0.1 to 1.0 parts by weight. In some cases, the compound having an epoxycyclohexyl group or the compound having an epoxycyclopentyl group may be used in combination with another epoxy compound such as glycidyl ether.

The triaryl phosphate and triaryl phosphite used in the present invention have 18 to 70 carbon atoms.
Those having 18 to 50 carbon atoms are more preferable. Specifically, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, tris (tribromophenyl) phosphate, tris (dibromophenyl) phosphate. Triaryl phosphates such as phosphates, tris (2,4-di-t-butylphenyl) phosphate, trinonylphenylphosphate, triphenylphosphite, tricresylphosphite, trixylenylphosphite, cresyl Diphenyl phosphite,
Xylenyl diphenyl phosphite, tris (2,4-di-t-butylphenyl) phosphite, trinonyl phenyl phosphite, tris (tribromophenyl)
Examples include triaryl phosphites such as phosphite and tris (dibromophenyl) phosphite.
The amount of triaryl phosphate and / or triaryl phosphite added is such that the amount of ester used in the present invention is 100%.
It is usually 0.1 to 5.0 parts by weight with respect to parts by weight, preferably
0.2 to 2.0 parts by weight.

The amount of benzotriazole and / or benzotriazole derivative used in the present invention is usually 0.001 to 0.1 with respect to 100 parts by weight of the ester used in the present invention.
Parts by weight, preferably 0.003 to 0.03 parts by weight.
The benzotriazole and benzotriazole derivatives used in the present invention have 6 to 50 carbon atoms, preferably 6 to 30 carbon atoms. Specifically, benzotriazole, 5-methyl-1H-benzotriazole, 1-
Dioctylaminomethylbenzotriazole, 1-dioctylaminomethyl-5-methylbenzotriazole,
2- (5'-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, and preferably benzotriazole and 5-methyl-
1H-benzotriazole and the like.

The amount of the metal deactivator used in the present invention is usually 100 parts by weight of the ester used in the present invention.
It is 0.001 to 2.0 parts by weight, preferably 0.003 to 0.5 parts by weight. The metal deactivator used in the present invention preferably has a chelating ability, and has 5 to 50 carbon atoms, preferably 5 to 20 carbon atoms. Specifically, N, N'-disalicylidene-1,2-diaminoethane, N, N'-disalicylidene-1,2-diaminopropane, N-salicylidene-N '
-Dimethyl-1,2-diaminoethane, N, N'-disalicylidenehydrazine, N, N'-bis (α, 5-dimethylsalicylidene) -1,2-diaminoethane, N, N'- Bis (α, 5-dimethylsalicylidene) -1,3-propanediamine, N, N '
-Bis (α, 5-dimethylsalicylidene) -1,6-hexanediamine, N, N'-bis (α, 5-dimethylsalicylidene) -1,10-decanediamine, N, N'-bis (Α, 5-Dimethylsalicylidene) ethylene tetraamine, salicylaldoxime, 2-hydroxy-5-methylacetophenoxime, acetylacetone, ethyl acetoacetate, 2-ethylhexyl acetoacetate, dimethyl malonate, diethyl malonate, malon Acid 2-ethylhexyl, anthranilic acid, nitonilotriacetic acid, dihydroxyethylglycine,
Hydroxyethylethylenediamine triacetic acid, hydroxyethyliminodiacetic acid, ethylenediamine, 3-mercapto-1,2-propanediol, alizarin, quinizanin, mercaptobenzothiazole and the like, and preferably N, N'-disalicylidene-1,2- Diaminoethane, N,
Examples thereof include N'-disalicylidene-1,2-diaminopropane, acetylacetone, acetoacetic acid ester, alizarin, quinizarin and the like.

If necessary, a lubricating oil additive such as an extreme pressure agent, an oiliness improver, and a defoaming agent other than those shown above may be added. Extreme pressure agents, those that can be used as oiliness improvers include zinc compounds such as zinc dialkyldithiophosphates and zinc diaryldithiophosphates,
Thiodipropionic acid ester, dialkyl sulfide, dibenzyl sulfide, dialkyl polysulfide, alkyl mercaptan, dibenzothiophene, 2,
A sulfur compound such as 2′-dithiobis (benzothiazole),
Phosphorus compounds such as trialkyl phosphites and trialkyl phosphates, chlorine compounds such as chlorinated paraffins,
Molybdenum dithiocarbamate, molybdenum dithiophosphate, molybdenum compounds such as molybdenum disulfide,
Examples include perfluoroalkyl polyethers, trifluoroethylene chloride polymers, fluorinated compounds such as fluorinated graphite, silicon compounds such as fatty acid-modified silicone, and graphite. The amount added is 0.05 to 10 parts by weight with respect to 100 parts by weight of the ester used in the present invention.

As the defoaming agent, silicone oil such as dimethylpolysiloxane and organosilicates such as diethyl silicate are used. The amount added is 0.0005 to 1 part by weight per 100 parts by weight of the ester used in the present invention. Further, an additive such as an organic tin compound or a boron compound which stabilizes the chlorofluorocarbon refrigerant may be added. The amount added is 0.001 to 10 parts by weight with respect to 100 parts by weight of the ester used in the present invention.

The refrigerating machine working fluid composition of the present invention can be easily prepared by blending a hydrofluorocarbon and an oil obtained by adding an additive to the ester used in the present invention as described above by a conventional method. .. The mixing ratio is
Usually, hydrofluorocarbon / oil = 5/1 to 1/10
(Weight ratio), preferably 2/1 to 1/5 (weight ratio).

The hydrofluorocarbons used in the present invention are 1,1-difluoroethane (HFC152a), 1,
1,1-trifluoroethane (HFC143a), 1,1,1,2-
Tetrafluoroethane (HFC134a), pentafluoroethane (HFC125), 1,1,2,2-tetrafluoroethane (HFC134), difluoromethane (HFC32), etc., especially 1,1,1,2-tetrafluoroethane Is preferred.

The base oil of the oil used in the working fluid of the present invention may be a mixture of the ester of A) and / or B) with another ester such as a hindered ester or diester. The mixing weight ratio at that time may be any as long as it does not impair the performance such as compatibility with hydrofluorocarbon, and generally, the weight ratio of the ester of A) and / or B) / the other ester is 100/0 to 5 / 95, preferably 100
/ 0 to 10/90, more preferably 100/0 to 30/70.

[0044]

EFFECT OF THE INVENTION A composition containing an oil obtained by adding an additive to the ester of A) and / or B) of the present invention and a hydrofluorocarbon is excellent in compatibility, lubricity, thermal stability and electric insulation. It is a thing.

[0045]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to these examples.

Example 1 A 1-liter four-necked flask was equipped with a stirrer, a thermometer, a nitrogen blowing tube, and a dehydration tube equipped with a condenser. Neopentyl glycol 104 g (1.0 mol), 2-methylhexanoic acid 137.8 g (1.06 mol) and adipic acid 62.8 g (0.43 mo)
l) was placed in the flask and esterified at 240 ° C. for 10 hours in a nitrogen stream to obtain ester A. Further, using alcohols and carboxylic acids shown in Table 1, the same reaction was carried out to obtain Esters B to F.

The hydroxyl value, kinematic viscosity at 40 ° C. and 100 ° C., and viscosity index (JIS K-2283) of these esters used in the present invention were measured. In addition, pour point (JIS K-2269)
Was measured. The results are shown in Table 1. In addition, the two-phase separation temperature of these esters at low temperature was measured at various sample concentrations of 10 vol% for 1,1,1,2-tetrafluoroethane. The results are also shown in Table 1.

[0048]

[Table 1]

Table 2 shows the compositions of oils 1 to 20 used in the products of the present invention and oils 1 to 6 used in the comparative products prepared by adding additives to these esters. The numerical values in the table represent the amount of additives (parts by weight) relative to 100 parts by weight of ester.
The additives a to n are shown below.

A: 2- (7-oxabicyclo [4.1.0]]
Hept-3-yl) -spiro [1,3-dioxane-5,3 '
-[7] oxabicyclo [4.1.0] heptane) b: 4-epoxyethyl-1,2-epoxycyclohexane c: bis (3,4-epoxycyclohexylmethyl) adipate d: 1,2-epoxycyclopentane e: Phenyl glycidyl ether f: 2-ethylhexyl glycidyl ether g: tricresyl phosphate h: trixylenyl phosphate i: tricresyl phosphite j: tris (2,4-di-t-butylphenyl) phosphite k: Benzotriazole 1: 5-methyl-1H-benzotriazole m: N, N′-disalicylidene-1,2-diaminoethane n: acetylacetone

[0051]

[Table 2]

Example 2 The oil obtained in Example 1 (oils 1 to 16, 1 used in the product of the present invention)
9 and 20, oils 1 to 6 used for comparative products and 1,1,1,2 respectively
-Inventive products 1-16, 19, 20 and comparative products 1-6, which are compositions with tetrafluoroethane (HFC134a), are subjected to a shield tube test under the conditions shown below in order to examine hydrolysis resistance. It was That is, take 10 g of oil and 5 g of HFC134a in a glass tube, and add water to the oil to 500 ppm.
In addition, iron, copper and aluminum were added as catalysts and the tube was sealed. After testing at 175 ° C. for 14 days, the sealed tube was opened, and the acid value of the oil after removing freon was examined. The results are shown in Table 3.

[0053]

[Table 3]

As is apparent from Table 3, the products of the present invention (1 to 16) containing a compound having an epoxycyclopentyl group or an epoxycyclohexyl group and the products of the present invention containing a phenylglycidyl ether or 2-ethylhexylglycidyl ether (19, 20) 2) had a remarkably lower acid value than the comparative products (1 to 6) which did not contain), and was effective in preventing carboxylic acid formation.
Further, the product (1 to 16) of the present invention containing a compound having an epoxycyclopentyl group or an epoxycyclohexyl group has a lower acid value than the product (19, 20) of the present invention containing phenyl glycidyl ether or 2-ethylhexyl glycidyl ether,
Excellent in preventing carboxylic acid formation.

Example 3 Products 7 to 12 of the present invention containing benzotriazole or a benzotriazole derivative and products 1, 2, 4 of the present invention not containing them
5, 6, and 14 were used to investigate the copper plating prevention effect of benzotriazole and benzotriazole derivatives.
That is, take 10 g of oil and 5 g of HFC134a in a glass tube,
2-Methylhexanoic acid copper salt was added to the oil in an amount of 1%, and iron, copper and aluminum were added as catalysts and the tube was sealed. 175 ° C
After 14 days of test, the presence or absence of copper plating was visually confirmed. As a result, as shown in Table 4, the addition of benzotriazole or a benzotriazole derivative could prevent the occurrence of copper plating.

[0056]

[Table 4]

Example 4 In order to examine the effect of the triaryl phosphate or triaryl phosphite on improving the wear resistance, the products of the present invention 2, 5, 8, 10, 12, 14, 15, 18, and Comparative product 1 were used. ~
6. In addition, naphthenic oil and polyether compounds and HFC134a
A Falex test was conducted on a composition (comparative products 7 to 9) consisting of That is, 1,1,1,2-tetrafluoroethane (HFC13
4a) is sprinkled into the oil at 150cc per minute, spun at unloaded for 10 minutes, then pre-spun at 200 lbs for 5 minutes, then at 350 lbs.
After running for 60 minutes, the amount of wear of the V block and the pin after running was examined. The results are shown in Table 5.

[0058]

[Table 5]

As is clear from Table 5, even in the compositions (comparative products 1 to 6) composed of the ester and HFC134a used in the product of the present invention, the naphthene oil or the polyether compound and HF were used.
Abrasion resistance is sufficiently superior to the composition comprising C134a (Comparative products 7 to 9), but containing triaryl phosphate or triaryl phosphite (inventive products 2, 5, 8, 10, 12) , 14, 15, 18) have significantly improved wear resistance.

Example 5 In order to investigate the low temperature compatibility of the products 1 to 20 of the present invention, 1,1,1,2-
Two-phase separation temperature at low temperature was measured at various sample concentrations of 10 vol% for tetrafluoroethane. The results are shown in Table 6.

[0061]

[Table 6]

As is clear from Table 6, all the products of the present invention have a low low temperature two-phase separation temperature and are good.

Example 6 A shielded tube test was conducted to examine the thermal stability of the products 1 to 20 of the present invention. That is, oil 10g, H in the glass tube
FC134a (5 g) was taken, and iron, copper, and aluminum were added as a catalyst, and the tube was sealed. After testing at 175 ℃ for 14 days, HFC
The appearance of the composition of 134a and oil and the presence or absence of deposits were examined. The results are shown in Table 7.

[0064]

[Table 7]

As is apparent from Table 7, all the products of the present invention had a good appearance, no precipitates, and good thermal stability.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10M 133: 44 129: 18 129: 74 7419-4H 129: 72 129: 76 129: 24 133: 06 133: 16) C10N 20:00 Z 8217-4H 30:00 Z 8217-4H C 8217-4H D 8217-4H 30:06 30:08 30:14 40:30

Claims (10)

[Claims] 1. 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 the same. An ester obtained from the derivative and (c) a linear or branched saturated aliphatic dicarboxylic acid having 2 to 10 carbon atoms or a derivative thereof, and B) (a) an aliphatic having 1 to 6 primary hydroxy groups An ester obtained from a polyhydric alcohol, (d) a linear or branched saturated aliphatic monohydric alcohol having 1 to 10 carbon atoms, and (e) a polyhydric carboxylic acid having 2 to 10 carbon atoms or a derivative thereof. At least one ester selected from the group consisting of triaryl phosphate and / or triaryl phosphite per 100 parts by weight of the ester.
0.1 to 5.0 parts by weight, benzotriazole and / or benzotriazole derivative 0.001 to 0.1 parts by weight, compound having an epoxy group 0.05 to 2.0 parts by weight, metal deactivator having chelating ability 0.001 to 2.0 parts by weight selected from the group consisting of A composition for refrigerating machine working fluid, which contains hydrofluorocarbon, and a refrigerating machine oil containing at least one kind thereof. 2. 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 the same. An ester obtained from the derivative and (c) a linear or branched saturated aliphatic dicarboxylic acid having 2 to 10 carbon atoms or a derivative thereof, and B) (a) an aliphatic having 1 to 6 primary hydroxy groups An ester obtained from a polyhydric alcohol, (d) a linear or branched saturated aliphatic monohydric alcohol having 1 to 10 carbon atoms, and (e) a polyhydric carboxylic acid having 2 to 10 carbon atoms or a derivative thereof. Refrigerating machine oil comprising 0.05 to 2.0 parts by weight of a compound having an epoxy group based on 100 parts by weight of the ester, and one or more esters selected from the above, and a composition for a working fluid of a refrigerator containing hydrofluorocarbon .. 3. 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 the same. An ester obtained from the derivative and (c) a linear or branched saturated aliphatic dicarboxylic acid having 2 to 10 carbon atoms or a derivative thereof, and B) (a) an aliphatic having 1 to 6 primary hydroxy groups An ester obtained from a polyhydric alcohol, (d) a linear or branched saturated aliphatic monohydric alcohol having 1 to 10 carbon atoms, and (e) a polyhydric carboxylic acid having 2 to 10 carbon atoms or a derivative thereof. 0.05 to 2.0 parts by weight of a compound having an epoxy group per 100 parts by weight of the ester, and triaryl phosphate and / or triaryl phosphite 0.1 to 0.1 to 1 or more esters selected from
Refrigerating machine oil containing 5.0 parts by weight, benzotriazole and / or benzotriazole derivative 0.001 to 0.1 parts by weight, and at least one selected from the group consisting of 0.001 to 2.0 parts by weight of a metal deactivator having a chelating ability. And a composition for a working fluid of a refrigerator containing hydrofluorocarbon. 4. The hydrofluorocarbon is 1,1,1,2-
It is tetrafluoroethane, The composition for refrigerator working fluids in any one of Claims 1-3. 5. The composition for refrigerator working fluid according to claim 1, wherein the compound having an epoxy group is an alicyclic epoxy compound. 6. The refrigerator working fluid composition according to claim 5, wherein the alicyclic epoxy compound is a compound having an epoxycyclohexyl group and / or a compound having an epoxycyclopentyl group. 7. The ester A) comprises (f) a component (a), an aliphatic dihydric alcohol having 1 to 2 primary hydroxy groups, and (b) a straight chain having 2 to 9 carbon atoms or An ester obtained from a branched saturated aliphatic monocarboxylic acid or a derivative thereof and (g) (c) a linear or branched saturated aliphatic dicarboxylic acid having 2 to 8 carbon atoms or a derivative thereof. And the ester B) is (f) a component of (a), an aliphatic divalent alcohol having 1 to 2 primary hydroxy groups, and (d) a straight or branched chain having 1 to 10 carbon atoms. 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. The composition for a working fluid of a refrigerator according to any one of 1. 8. The hydroxyl value of the ester is 5 mgKOH / g or more.
The composition for refrigerator working fluid according to any one of claims 1 to 3, which has a content of 30 mgKOH / g or less. 9. The ester is (a) neopentyl glycol or 2,2-diethyl-1,3-propanediol, and (b)
The composition for refrigerator working fluid according to claim 7, which is an ester obtained from 2-methylhexanoic acid and (g) adipic acid or glutaric acid. 10. The refrigerator working fluid composition according to claim 9, wherein the ester has a hydroxyl value of 5 mgKOH / g or more and 30 mgKOH / g or less.