JP2002105471A - Lubricating oil composition for refrigerating machine and working fluid composition for refrigerating machine using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricating oil composition for a refrigerating machine which particularly exhibits excellent compatibility with difluoromethane, and a working fluid composition for a refrigerating machine which comprises this lubricating oil composition for a refrigerating machine and the above refrigerant and excels in wear resistance, lubricating properties, stability and the like. SOLUTION: The lubricating oil composition for a refrigerating machine comprises (a) a polyester based derivative as the base oil and (b) 0.1 wt.% to less than 60 wt.%, based on the total amount of the base oil, polycarbonate based oxygen-containing compound and has a two-phase separation temperature at the lower temperature side of <=10 deg.C in any content in the range shown below when incorporated into a chlorine-free 1C refrigerant in an amount of 3-50 wt.% based on the total amount. The work fluid composition for a refrigerating machine comprises (A) a chlorine-free 1C refrigerant and (B) the above lubricating oil composition for a refrigerating machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lubricating oil composition for a refrigerator and a working fluid composition for a refrigerator using the same. More specifically, the present invention relates to a lubricating oil composition for refrigerators having excellent compatibility with chlorine-free refrigerants having 1 carbon atom, particularly difluoromethane, and a lubricating oil composition for refrigerators and the refrigerant described above. And a working fluid composition for a refrigerator having excellent wear resistance, lubricating properties, electrical properties, stability, and the like.

[0002]

2. Description of the Related Art In general, a compression refrigerator comprises at least a compressor, a condenser, an expansion mechanism (expansion valve, etc.), an evaporator, or a dryer. It has a structure that circulates inside. In such a compression type refrigerator, although it depends on the type of equipment, generally, the temperature in the compressor is high and the temperature in the cooler is low, so the refrigerant and lubricating oil phase-separate within a wide temperature range from low to high. It is necessary to circulate in this system without doing. Generally, the refrigerant and the lubricating oil have a region where phase separation occurs on the low temperature side and the high temperature side, and the maximum temperature of the low temperature side separation region is desirably 10 ° C or lower, preferably 8 ° C or lower. The temperature is more preferably 5 ° C or lower, and further preferably 2 ° C or lower. If phase separation occurs during the operation of the refrigerator, the life and efficiency of the device will be significantly adversely affected. For example, when the phase separation of the refrigerant and the lubricating oil occurs in the compressor part, the moving part becomes inadequately lubricated, causing seizure or the like to significantly shorten the life of the device, while the phase separation occurs in the evaporator, The presence of the lubricating oil having a high viscosity causes a reduction in the efficiency of heat exchange.

[0003] Conventionally, as a refrigerant of a compression refrigerator, particularly an air conditioner, chlorodifluoromethane (hereinafter referred to as R22) or a chlorodifluoromethane and chloropentafluoroethane having a weight ratio of 48.8: 51.2. Mixture (hereinafter,
Called R502. ) Is often used, and as the lubricating oil, various mineral oils and synthetic oils satisfying the above-mentioned required characteristics have been used. However, since R22 and R502 may cause environmental pollution such as destruction of the ozone layer existing in the stratosphere, the regulations thereof have recently become stricter worldwide. Therefore, as a new refrigerant 1,
1,1,2-tetrafluoroethane, difluoromethane, pentafluoroethane, 1,1,1-trifluoroethane (hereinafter, R134a, R32, R12
5, R143a. ) Is attracting attention. This hydrofluorocarbon, especially R134a,
R32, R125, and R143a have no risk of destruction of the ozone layer and are preferred as refrigerants for compression refrigerators.

Further, from the viewpoint of energy saving, further measures have been required, and among the above-mentioned new refrigerants,
In particular, difluoromethane (R32) has attracted attention. However, the R32 refrigerant has a higher working pressure and temperature than conventional refrigerants, and is likely to cause new lubrication problems. In lubricating oils for refrigerators, which have been studied so far for the new refrigerant, the R
In fact, none of them show sufficient compatibility with R.32, and R134a, R407c, (a mixture of R32, R125, and R134a in a weight ratio of 23:24:52), R
The development of a lubricating oil for refrigerators having the same level of compatibility as 410A (a mixture of R32 and R125 at a weight ratio of 50:50) has been awaited.

[0005]

SUMMARY OF THE INVENTION Under such circumstances, the present invention provides a lubricating oil for a refrigerator having excellent compatibility with a chlorine-free refrigerant having 1 carbon atom, particularly difluoromethane (R32). An object of the present invention is to provide a composition and a working fluid composition for a refrigerator including the lubricating oil composition for a refrigerator and the above-described refrigerant, and having excellent wear resistance, lubricating properties, stability, and the like.

[0006]

The present inventors have studied the compatibility of a polyether compound such as a polyvinyl ether derivative or an oxygen-containing compound such as a polyol ester derivative in an atmosphere of R32 refrigerant. However, these compounds did not always have sufficient compatibility with R32. The present inventors have further studied intensively to achieve the above object, and as a result, a polyester-based derivative having a predetermined viscosity,
A polycarbonate-based oxygenated compound having a predetermined viscosity,
In particular, those obtained by mixing a polycarbonate compound having two or more carbonate bonds in one molecule at a specific ratio,
In the low temperature region, it has excellent compatibility with chlorine-free refrigerants having 1 carbon atom, particularly R32, and
It has been found that this and the one containing the above-mentioned refrigerant can be suitable for the above purpose as a working fluid composition for a refrigerator. The present invention has been completed based on such findings.

That is, the present invention provides (a) a base oil comprising:
A polyester derivative of kinematic viscosity 3~500mm ² / s at 40 ° C., based on the base oil the total amount, (b) a kinematic viscosity at 40 ° C. is 3~500mm ² / s of the polycarbonate-based oxygenates 0.1 wt% A lubricating oil composition for a refrigerator containing at least 60% by weight and containing 3 to 50% by weight based on the total amount of a chlorine-free refrigerant having 1 carbon atom; The lubricating oil composition for refrigerators is characterized in that the low-temperature-side two-layer separation temperature is 10 ° C. or lower. Particularly preferably, the polycarbonate-based oxygen-containing compound as the component (b) is a polycarbonate having two or more carbonate bonds in one molecule, and (a) the general formula (I)

[0008]

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Wherein Z is a residue obtained by removing a hydroxyl group from an n-valent alcohol having 1 to 12 carbon atoms, and R ¹ is a residue having 2 to 10 carbon atoms.
A linear or branched alkylene group, and R ² has 1 carbon atom
To 12 monovalent hydrocarbon groups or R ⁴ (OR ³ ) _p −
(Where R ⁴ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms, R ³ is a linear or branched alkylene group having 2 to 10 carbon atoms, and p is an integer of 1 to 20). ), A group containing an ether bond, k is an integer of 1 to 30, m
Represents an integer of 1 to 50, and n represents an integer of 1 to 6. A) a compound represented by the general formula (II):

[0010]

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(Wherein, R ⁵ is a linear or branched alkylene group having 2 to 10 carbon atoms, q is an integer of 1 to 20, and Z, R ¹ , R ² , k, m and n are as defined above) The present invention provides a lubricating oil composition for refrigerators, which is at least one selected from the compounds represented by the formula:
The present invention also provides a working fluid composition for a refrigerator, comprising (A) a chlorine-free refrigerant having 1 carbon atom and (B) the lubricating oil composition for a refrigerator as essential components. To provide. The lubricating oil composition for a refrigerator according to the present invention may be used under conditions in which the refrigerant has 1 carbon atom and no chlorine.
, Especially a fluorinated hydrocarbon-based refrigerant containing no chlorine, tends to have a high internal pressure and a high operating temperature. Therefore, if necessary the hardness difference between the members forming the metal sliding portion of the compression mechanism is set to 10 or more H _RC equivalent, the side of a small member of hardness securing the wear resistance of conventional by conventional hardness Meanwhile, by improving the wear resistance of the other member sufficiently than before, the wear resistance of the required portion of the metal sliding portion is improved, and the fluorocarbon refrigerant does not contain chlorine. The resistance to the fact that the lubrication effect cannot be expected is obtained. In addition, the fact that the sliding member on the higher hardness side easily promotes the wear of the sliding member on the lower hardness side is determined by at least one of orthophosphate, phosphite, and acid phosphate. It is considered that the addition of the compound compensates for insufficient lubrication due to the fact that the fluorocarbon-based refrigerant does not contain chlorine by acting as an extreme pressure agent.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the lubricating oil composition for a refrigerator according to the present invention will be described. The lubricating oil composition for a refrigerator according to the present invention has, as a base oil, (a) a kinematic viscosity at 40 ° C of 3 to 5;
(B) The kinematic viscosity at 40 ° C. is 3 to 500 mm based on the polyester-based derivative of 00 mm ² / s and the total amount of the base oil.
² / s polycarbonate oxygen-containing compound containing 0.1% by weight or more and less than 60% by weight. And, when it is contained in a range of 3 to 50% by weight based on the total amount with respect to a chlorine-free refrigerant having 1 carbon atom, for example, R32, it is compatible at a temperature of 10 ° C. or less at any one of the contents. (The liquid phase is uniform). Here, the content of the lubricating oil in which the lubricating oil and the refrigerant are compatible at a temperature of 10 ° C. or less may be any of the above 3 to 50% by weight, preferably 10% by weight or 15% by weight, Particularly preferably, it is desirable to cover the entire range of 3 to 50% by weight. If the compatibility temperature, that is, the low-temperature two-layer separation temperature exceeds 10 ° C., phase separation may occur during the operation of the refrigerator. If phase separation occurs during operation of the refrigerator, the life and efficiency of the device will be significantly adversely affected. For example, if phase separation between refrigeration and lubricating oil occurs in the compressor part, the moving parts will be inadequately lubricated, causing seizure etc., significantly shortening the life of the device, while if phase separation occurs in the evaporator, The presence of the lubricating oil having a high viscosity causes a reduction in the efficiency of heat exchange.

For these reasons, the maximum temperature of the low-temperature side separation region needs to be 10 ° C. or less, and preferably 8 ° C. or less. The temperature is more preferably 5 ° C or lower, and further preferably 2 ° C or lower. Examples of the polyester derivative used as the component (a) of the base oil in the lubricating oil composition for refrigerators of the present invention include aromatic esters, dibasic acid esters, polyol esters, complex esters, carbonate esters, and mixtures thereof. And the like.

The aromatic ester is usually divalent to hexavalent,
It is preferably a divalent to tetravalent, more preferably divalent to trivalent aromatic carboxylic acid, and usually has 1 to 18 carbon atoms, preferably 1 to 1 carbon atom.
And an ester with an aliphatic alcohol.
Examples of the divalent to hexavalent aromatic carboxylic acid include phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, and mixtures thereof. The aliphatic alcohol having 1 to 18 carbon atoms may be linear or branched, and for example, methanol, ethanol, linear or branched propanol, linear or branched Butanol, linear or branched pentanol, linear or branched hexanol, linear or branched heptanol, linear or branched octanol, linear or branched nonanol, Linear or branched decanol, linear or branched undecanol, linear or branched dodecanol, linear or branched tridecanol, linear or branched tetradecanol, linear or Branched pentadecanol, linear or branched hexadecanol, linear or branched heptadecanol, linear or branched octadecanol and mixtures thereof Things and the like. Examples of the aromatic ester include dibutyl phthalate and di (phthalate) (2
-Ethylhexyl), dinonyl phthalate, didecyl phthalate, didodecyl phthalate, ditridecyl phthalate, trisbutyl trimellitate, tris trimellitate (2
-Ethylhexyl), trisnonyl trimellitate, trisdecyl trimellitate, trisdodecyl trimellitate, tristridecyl trimellitate and the like. Of course, when a divalent or higher aromatic carboxylic acid is used, it may be a simple ester composed of one kind of aliphatic alcohol or a complex ester composed of two or more kinds of aliphatic alcohols. Is also good.

As the dibasic acid ester, glutaric acid,
Adipic acid, pimelic acid, suberic acid, azelaic acid,
C5-10 dibasic acids such as sebacic acid and methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol,
Nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, esters with a monovalent alcohol having 1 to 15 carbon atoms having a linear or branched alkyl group such as pentadecanol and mixtures thereof are preferably used, More specifically, examples thereof include ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, and mixtures thereof.

The polyol ester includes a diol or a polyol having 3 to 20 hydroxyl groups.
Esters with fatty acids having 6 to 20 carbon atoms are preferably used. Here, as the diol, for example, ethylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 1,5-
Pentanediol, neopentyl glycol, 1,6-
Hexanediol, 2-ethyl-2-methyl-1,3-
Propanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3-propanediol, 2,
2-diethyl-1,3-propanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-
Decanediol, 1,11-undecanediol, 1,
12-dodecanediol and the like. Examples of the polyol include trimethylolethane, trimethylolpropane, trimethylobutane, di- (trimethylolpropane), tri- (trimethylolpropane),
Pentaerythritol, di- (pentaerythritol), tri- (pentaerythritol), glycerin,
Polyglycerin (2-20 mer of glycerin), 1,
3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerin condensate, polyhydric alcohols such as adonitol, arabitol, xylitol, mannitol, xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose And saccharides such as isomaltose, trehalose, sucrose, raffinose, gentianose, and melenitose, and partially etherified products thereof, and methylglucoside (glycoside). Among these polyols, neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di- (trimethylolpropane), tri- (trimethylolpropane), pentaerythritol, di- (pentaerythritol), tri- Hindered alcohols such as-(pentaerythritol) are preferred.

The aliphatic is not particularly limited in the number of carbon atoms, but usually has 1 to 24 carbon atoms. Among fatty acids having 1 to 24 carbon atoms, those having 3 or more carbon atoms are preferable from the viewpoint of lubricity, those having 4 or more carbon atoms are more preferable, those having 5 or more carbon atoms are even more preferable, and those having 10 or more carbon atoms are more preferable. Are most preferred. Further, from the viewpoint of compatibility with the refrigerant, those having 18 or less carbon atoms are preferable,
Those having 2 or less are more preferred, and those having 9 or less carbon atoms are even more preferred. Further, any of a linear fatty acid and a branched fatty acid may be used, and a linear fatty acid is preferable from the viewpoint of lubricity, and a branched fatty acid is preferable from the viewpoint of hydrolysis stability. Further, any of saturated fatty acids and unsaturated fatty acids may be used.

Examples of the fatty acid include pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, and octadecanoic acid , Nonadecanoic acid, icosanoic acid,
Examples thereof include linear or branched ones such as oleic acid, and so-called neo acids having a quaternary α carbon atom.
More specifically, valeric acid (n-pentanoic acid), caproic acid (n-hexanoic acid), enanthic acid (n-heptanoic acid), caprylic acid (n-octanoic acid), pelargonic acid (n-nonanoic acid) , Capric acid (n-decanoic acid), oleic acid (cis-9-octadecenoic acid), isopentanoic acid (3-methylbutanoic acid), 2-methylhexanoic acid,
-Ethylpentanoic acid, 2-ethylhexanoic acid, 3,5
5-Trimethylhexanoic acid and the like are preferred. The polyol ester may be a partial ester in which all the hydroxyl groups of the polyol are left unesterified, or a complete ester in which all the hydroxyl groups are esterified, or a partial ester and a complete ester. May be used, but is preferably a complete ester.

Complex esters are esters of fatty acids and dibasic acids with monohydric alcohols and polyols. Fatty acids, dibasic acids, monohydric alcohols and polyols include dibasic esters and polyols. The same ones as exemplified in the description of the ester can be used. Further, as a matter of course, the ester referred to in the present invention may be composed of one kind of ester having a single structure, or may be a mixture of two or more kinds of esters having different structures. Among these various esters, polyol esters are preferred because of their excellent compatibility with the refrigerant. Among the polyol esters, since they have more excellent hydrolysis stability, neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di- (trimethylolpropane), tri- (trimethylolpropane), pentaerythritol, Di- (pentaerythritol), tri-
Esters of hindered alcohols such as (pentaerythritol) are more preferred, neopentyl glycol,
Esters of trimethylolethane, trimethylolpropane, trimethylolbutane and pentaerythritol are even more preferred, and esters of pentaerythritol are most preferred because they are particularly excellent in compatibility with a refrigerant and hydrolytic stability.

Specific examples of preferred polyol esters include neopentyl glycol and valeric acid, caproic acid,
Enanthic acid, caprylic acid, pelargonic acid, capric acid,
Oleic acid, isopentanoic acid, 2-methylhexanoic acid,
2-ethylpentanoic acid, 2-ethylhexanoic acid, 3,
Diesters of one or more fatty acids selected from 5,5-trimethylhexanoic acid, trimethylolethane and valeric acid, caproic acid, enanthic acid, caprylic acid,
Pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2
-Ethylhexanoic acid, triester with one or more fatty acids selected from 3,5,5-trimethylhexanoic acid, trimethylolpropane and valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, Capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid,
Triester with one or more fatty acids selected from 3,5,5-trimethylhexanoic acid, trimethylolbutane and valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid Triester with one or more fatty acids selected from isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, 3,5,5-trimethylhexanoic acid, pentaerythritol And valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, 3,5,5-trimethyl Examples include tetraesters with one or more fatty acids selected from hexanoic acid.

The ester of two or more kinds of fatty acids may be a mixture of two or more kinds of esters of one kind of fatty acids and polyols, and the esters of two or more kinds of mixed fatty acids and polyols, especially the mixed fatty acids and polyols. Are excellent in low-temperature properties and compatibility with refrigerants. Other than these, JP-A-4-183788 and 5-1779
No. 2, No. 8-226717, No. 8-2319
No. 72, No. 8-240352, No. 8-240
No. 362, No. 8-253779, No. 8-25
The ester compound disclosed in Japanese Patent No. 9975 can also be suitably used. The polyester derivative of the component (a) has a kinematic viscosity at 40 ° C. of 3 to 500 mm.
² / s, preferably 5 to 300 mm ² / s, more preferably 8 to 150 mm ² / s.

On the other hand, the polycarbonate oxygenates used as the component (b) of the base oil include polycarbonates having two or more carbonate bonds in one molecule.
That is, the general formula (I)

[0023]

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Wherein Z is a residue obtained by removing a hydroxyl group from an n-valent alcohol having 1 to 12 carbon atoms, and R ¹ is a residue having 2 to 10 carbon atoms.
A linear or branched alkylene group, and R ² has 1 carbon atom
To 12 monovalent hydrocarbon groups or R ⁴ (OR ³ ) _p −
(Where R ⁴ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms, R ³ is a linear or branched alkylene group having 2 to 10 carbon atoms, and p is an integer of 1 to 20). ), A group containing an ether bond, k is an integer of 1 to 30, m is 1
Integer of 50, n shows the integer of 1-6. A) a compound represented by the general formula (II):

[0025]

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(Wherein, R ⁵ is a linear or branched alkylene group having 2 to 10 carbon atoms, q is an integer of 1 to 20, and Z, R ¹ , R ² , k, m and n are as defined above) At least one selected from the compounds represented by the formula: In the general formulas (I) and (II), Z is a residue obtained by removing a hydroxyl group from a monovalent to hexavalent alcohol having 1 to 12 carbon atoms, and particularly a monovalent alcohol having 1 to 12 carbon atoms. The residue obtained by removing the hydroxyl group from the alcohol is preferred.

The monohydric to hexahydric alcohol having 1 to 12 carbon atoms having Z as a residue includes monohydric alcohols such as methyl alcohol, ethyl alcohol, n- or isopropyl alcohol, various butyl alcohols and various pentyls. Alcohol, various hexyl alcohols, various octyl alcohols, various decyl alcohols, various aliphatic monohydric alcohols such as dodecyl alcohol, cyclopentyl alcohol, cycloaliphatic monohydric alcohols such as cyclohexyl alcohol, phenol, cresol, xylenol, butylphenol, naphthol, etc. Aromatic alcohols such as aromatic alcohols, benzyl alcohols and phenethyl alcohols as dihydric alcohols such as ethylene glycol, propylene glycol, butylene glycol; Le, neopentyl glycol,
Aliphatic alcohols such as aliphatic alcohols such as tetramethylene glycol, cyclohexanediol and cyclohexanedimethanol, catechol, resorcinol,
Hydroquinone, aromatic alcohols such as dihydroxydiphenyl, as trihydric alcohols, for example, glycerin, trimethylolpropane, trimethylolethane,
Aliphatic alcohols such as trimethylolbutane and 1,3,5-pentanetriol; alicyclic alcohols such as cyclohexanetriol and cyclohexanetrimethanol; aromatic alcohols such as pyrogallol and methylpyrogallol; Examples thereof include aliphatic alcohols such as pentaerythritol, diglycerin, triglycerin, sorbitol and dipentaerythritol. As such a polycarbonate compound, a compound represented by the general formula (Ia) represented by the general formula (I)

[0028]

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(Wherein, R ⁶ is a residue obtained by removing a hydroxyl group from a monohydric alcohol having 1 to 12 carbon atoms, R ¹ , R ² , k and m
Is the same as above. And / or a compound represented by the general formula (II) is represented by the general formula (II-a):

[0030]

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Wherein R ¹ , R ² , R ⁵ , R ⁶ , k, m
And q are the same as above. )). The general formula (Ia) and the general formula (II
In -a), the residue obtained by removing a hydroxyl group from a monohydric alcohol having 1 to 12 carbon atoms represented by R ⁶ includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, various butyl groups, and various pentyl groups. Group, various hexyl groups, various octyl groups, various decyl groups, various dodecyl groups and other aliphatic hydrocarbon groups, cyclopentyl groups, cyclohexyl groups, methylcyclohexyl groups, dimethylcyclohexyl groups, decahydronaphthyl groups and other alicyclic hydrocarbons Group, phenyl group, various tolyl groups, various xylyl groups, mesityl groups, various naphthyl groups and other aromatic hydrocarbon groups, benzyl group, methylbenzyl group, phenethyl group, various naphthylmethyl groups and other aromatic hydrocarbon groups, etc. Can be mentioned.
Among these, a linear or branched alkyl group having 1 to 6 carbon atoms is preferable.

R¹Is a straight or branched chain having 2 to 10 carbon atoms.
A branched alkylene group, among which those having 2 to 6 carbon atoms
Are preferable, and particularly, ethylene group and propylene group
It is preferable from the viewpoints of ease of manufacture and the like. Further, R
^TwoIs a monovalent hydrocarbon group having 1 to 12 carbon atoms or R^Four(O-
R^Three)_p-(However, R^FourIs a hydrogen atom or carbon number 1 to 1
2, preferably 1 to 6 monovalent hydrocarbon groups, R^ThreeIs carbon
A linear or branched alkylene group of the number 2 to 10, p is
Shows an integer of 1 to 20. )
And a monovalent hydrocarbon group having 1 to 12 carbon atoms.
The R ⁶The same items as those exemplified in the description
I can do it. Also, R^Three2 to 1 carbon atoms represented by
0 linear or branched alkylene group,
R¹For the same reason as in the above, those having 2 to 6 carbon atoms are preferable.
Particularly, an ethylene group and a propylene group are particularly preferable.

As R ² , a linear or branched alkyl group having 1 to 6 carbon atoms is particularly preferred. General formula (II
In -a), the linear or branched alkylene group having 2 to 10 carbon atoms represented by R ⁵ is preferably a group having 2 to 6 carbon atoms for the same reason as in the case of R ¹ .
Particularly, an ethylene group and a propylene group are preferable. Such a polycarbonate compound can be produced by various methods, and is usually prepared by reacting a carbonate-forming derivative such as a diester carbonate or phosgene with an alkylene glycol or a polyoxyalkylene glycol according to a known method. Can be produced.

The lubricating oil composition for a refrigerator according to the present invention may contain, as the component (b) of the base oil, one kind of the polycarbonate compound represented by the general formula (I), or two or more kinds thereof. And may contain one kind of the polycarbonate compound represented by the general formula (II), or two or more kinds thereof. The kinematic viscosity at 40 ° C. of the polycarbonate compound (b) is 3
５００500 mm ² / s, preferably 5 to 200 mm
² / s, more preferably 5 to 150 mm ² / s.
The lubricating oil composition for a refrigerator according to the present invention comprises, as base oils, the aforementioned polyester-based derivative as the component (a) and the aforementioned polycarbonate-based oxygenated compound as the component (b) based on the total amount of the base oil. 0.1 to less than 60% by weight, preferably 0.5 to 55% by weight, more preferably 10 to 50% by weight
However, the base oil may further contain a hydrocarbon compound such as polyoxyalkylene glycol, a polyvinyl ether-based compound, mineral oil, or a poly-α-olefin.

The base oil in the lubricating oil composition for refrigerator of the present invention preferably has kinematic viscosity at 40 ° C. is in the range of 7~100mm ² / s, which is in the range of inter alia 8~90mm ² / s Are preferable, and those having a viscosity index of 40 or more are preferable, and among them, 50 to 130, particularly 60 to 1 are preferable.
Those in the range of 20 are preferred. The lubricating oil composition for a refrigerator of the present invention includes an acid scavenger, an extreme pressure agent, an oil agent,
It is preferable to include an antioxidant.

Examples of the acid scavenger include glycidyl ether group-containing compounds, epoxidized fatty acid monoesters,
Epoxidized oils and fats, epoxycycloalkyl group-containing compounds, and the like are included. Examples of extreme pressure agents include organic sulfides such as monosulfides, polysulfides, sulfoxides, sulfones, thiosulfinates, sulfurized fats and oils, thiocarbonates, thiophenes, thiazoles, and methanesulfonic acid esters. Compounds, phosphate monoesters, phosphate diesters, phosphate ester such as phosphate triesters (tricresyl phosphate, etc.), phosphite monoesters, phosphite diesters, Phosphorous esters such as phosphite triesters, thiophosphoric esters such as thiophosphoric triesters, higher fatty acids, hydroxyaryl fatty acids, polyhydric alcohol esters, acrylic acid esters, etc. Esters, chlorinated hydrocarbons, chlorinated carboxylic acid derivatives, etc. Chlorine-based, fluorinated aliphatic carboxylic acids, fluorinated ethylene resin, fluorinated alkylpolysiloxanes, organic fluorinated ones such as fluorinated graphite, alcoholic ones such as higher alcohols, naphthenates ( Metal compounds such as lead naphthenate, fatty acid salts (such as lead fatty acid), thiophosphates (such as zinc dialkyldithiophosphate), thiocarbamates, organic molybdenum compounds, organic tin compounds, organic germanium compounds, and borate esters And the like. Further, examples of the antioxidant include phenol-based compounds such as 2,6-di-tert-butyl-p-cresol and amine-based compounds such as α-naphthylamine.

Further, as the oily agent, (x) an etherified product of a trivalent to hexavalent aliphatic polyhydric alcohol or (y) a bimolecular condensate or a trimolecular condensate of a trivalent to hexavalent aliphatic polyhydric alcohol can be used. Etherified compounds are preferred. Next, the (x) component and the (y) component will be described. (X)
As the etherified product of the tri- to hexa-valent aliphatic polyhydric alcohol as a component, for example, those represented by the following general formulas (III-a) to (III-f) are preferable.

[0038]

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[In the formula, R ^{7 to} R ¹² each represent a hydrogen atom or a linear or branched alkyl group, aryl group or aralkyl group having 1 to 18 carbon atoms, which may be the same or different. . Further,-(R ^a O) _x -R ^b (R ^a
Is an alkylene group having 2 to 6 carbon atoms, and ^Rb is 1 to 20 carbon atoms.
An alkyl group, an aryl group or an aralkyl group, wherein x is 1 to
Indicates an integer of 10. ) Represents a glycol ether residue. ]. Specific examples of the tri- to hexa-valent aliphatic polyhydric alcohols include glycerin, trimethylolpropane, erythritol, pentaerythritol, arabitol,
Sorbitol, mannitol and the like can be mentioned. In the above general formulas (III-a) to (III-f),
R ⁷ ~R1 ^2, for example, a methyl group, an ethyl group, n- propyl group, an isopropyl group, various butyl groups, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, various decyl groups, Various undecyl groups,
Examples include various dodecyl groups, various tridecyl groups, various tetradecyl groups, various pentadecyl groups, various hexadecyl groups, various heptadecyl groups, various octadecyl groups, phenyl groups, and benzyl groups. Further, the case of a hydrogen atom, that is, a partially etherified product is also included.

With regard to the etherified product of the bimolecular condensate or trimolecular condensate of the tri- to hexavalent aliphatic polyhydric alcohol of the component (y), for example, the etherified product of the alcohol corresponding to the general formula (III-a) Are the general formulas (III-g) and (III-
The etherified product of the alcohol represented by h) and corresponding to the general formula (III-d) is represented by the general formulas (III-i) and (III-j).

[0041]

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(Wherein, R ^{7 to} R ¹⁴ are the same as R ^{7 to} R ¹² , and they may be the same or different.) Bimolecular condensate of a tri to hexavalent aliphatic polyhydric alcohol Specific examples of the trimolecular condensate include diglycerin, ditrimethylolpropane, dipentaerythritol, disorbitol, triglycerin, tritrimethylolpropane,
Tripentaerythritol, trisorbitol and the like can be mentioned.

Specific examples of the components (x) and (y) represented by the general formulas (III-a) to (III-j) include trihexyl ether of glycerin, dimethyloctyl triether of glycerin, and glycerin of glycerin. Di (methyloxyisopropylene) dodecyl triether, diphenyloctyl triether of glycerin, di (phenyloxyisopropylene) dodecyl triether of glycerin, trihexyl ether of trimethylolpropane, dimethyloctyl triether of trimethylolpropane, trimethylol Propane di (methyloxyisopropylene)
Dodecyl triether, pentaerythritol tetrahexyl ether, pentaerythritol trimethyloctyl tetraether, pentaerythritol tri (methyloxyisopropylene) dodecyl tetraether, sorbitol hexapropyl ether, sorbitol tetramethyloctyl pentaether, sorbitol hexa (Methyloxyisopropylene) ether, tetrabutylether of diglycerin, dimethyldioctyltetraether of diglycerin, tri (methyloxyisopropylene) dodecyltetraether of diglycerin, pentaethylether of triglycerin, trimethyldioctylpentaether of triglycerin ,
Tetra (methyloxyisopropylene) decylpentaether of triglycerin, tetrabutylether of ditrimethylolpropane, dimethyldioctyltetraether of ditrimethylolpropane, tri (methyloxyisopropylene) dodecyltetraether of ditrimethylolpropane, penta of tritrimethylolpropane Ethyl ether, trimethyldioctyl pentaether of tritrimethylolpropane, tetra (methyloxyisopropylene) decylpentaether of tritrimethylolpropane, hexapropylether of dipentaerythritol, pentamethyloctylhexaether of dipentaerythritol, hexa of dipentaerythritol (Methyloxyisopropylene) ether, tripentaerythritol Octapropyl ether, tripentaerythritol pentamethyloctyl hexaether, tripentaerythritol hexa (methyloxyisopropylene) ether, disorbitol octamethyldioctyldecaether, disorbitol deca (methyloxyisopropylene) ether and the like. be able to. Among them, diphenyloctyl triether of glycerin, di (methyloxyisopropylene) dodecyl triether of trimethylolpropane, tetrahexyl ether of pentaerythritol, hexapropyl ether of sorbitol, dimethyldioctyl tetraether of diglycerin, and dimethyldioctyl tetraether of triglycerin Tetra (methyloxyisopropylene) decyl pentaether, pentaerythritol hexapropylether,
Pentamethyloctyl hexaether of tripentaerythritol is preferred.

The kinematic viscosity of the components (x) and (y) at 40 ° C. is 50 to ²⁰⁰ mm ² / s, preferably 10 to 200 mm ² / s.
１００100 mm ² / s. If it is less than 5 mm ² / s, the effect of improving lubricity and the effect of preventing capillary clogging are small, and if it exceeds 200 mm ² / s, the compatibility with the refrigerant (two-layer separation temperature) is undesirably reduced. In the lubricating oil composition for a refrigerator of the present invention, the above-mentioned (x),
(Y) The component may be used alone or in combination of two or more. Further, the amount is preferably in the range of 0.1 to 30% by weight based on the total amount of the composition. When the amount is less than 0.1% by weight, the object of the present invention is not sufficiently exhibited. When the amount exceeds 30% by weight, the effect is not improved for the amount, and the solubility in the base oil decreases. May be. A more preferable blending amount is 0.1 to 15% by weight.
And particularly preferably in the range of 0.5 to 10% by weight.

The lubricating oil composition for refrigerators of the present invention contains other additives conventionally used in lubricating oils, such as metal deactivators, defoamers, detergents / dispersants, viscosity index improvers, and oiliness. Agents, antiwear additives, rust inhibitors, corrosion inhibitors, pour point depressants and the like can be included as desired. Benzotriazole derivatives and the like as metal deactivators, silicone oils (such as dimethylpolysiloxane) and polymethacrylates as defoamers, and sulfonates, phenates and succinimides as detergents and dispersants Examples of the viscosity index improver include polymethacrylate, polyisobutylene, an ethylene-propylene copolymer, and a styrene-diene hydrogenated copolymer.

Next, the working fluid composition for a refrigerator according to the present invention comprises:
It contains (A) a refrigerant having 1 carbon atom having no chlorine and (B) the lubricating oil composition for a refrigerator of the present invention described above. Difluoromethane (R32) can be cited as an example of the chlorine-free refrigerant having no component (A) and having 1 carbon atom. The content ratio of the component (A) to the component (B) is usually 5:95 to 99: 1, preferably 10: 9 by weight ratio.
It is selected in the range of 0 to 99: 1. When the amount of the refrigerant is less than the above range, the refrigerating capacity is reduced, and when it is more than the above range, the lubricating performance is undesirably reduced. The lubricating oil composition for a refrigerator of the present invention can be used for various refrigerators, but is particularly preferably applied to a compression refrigeration cycle of a compression refrigerator. For example, Japanese Patent Application Laid-Open No.
No. 3788, No. 8-259975, No. 8-2
Nos. 40362, 8-253779, 8-
JP-A-240352, JP-A-5-17792, JP-A-8-
226717, and 8-231972 are suitable for the refrigerating apparatus, and the lubricating oil composition for a refrigerator of the present invention is, for example, an oil as shown in each of FIGS. Even when applied to a compression refrigeration cycle having a separator and / or a hot gas line, the effect is effectively exerted.

FIG. 1 is a flow chart showing an example of a compression refrigeration cycle of "compressor-condenser-expansion valve-evaporator" having an oil separator and a hot gas line, and FIG. FIG. 3 is a flowchart showing an example of a compression-type refrigeration cycle of “compressor-condenser-expansion valve-evaporator” having a hot gas line. It is a flowchart which shows an example of a type refrigeration cycle.
Reference numeral 1 denotes a compressor, 2 denotes a condenser, 3 denotes an expansion valve, 4 denotes an evaporator, 5 denotes an oil separator, 6 denotes a hot gas line, and 7 denotes a hot gas line valve. Usually, the compression refrigeration cycle
It consists of a compressor-condenser-expansion valve-evaporator as shown in FIG. Generally, lubricating oil for refrigerators having good compatibility with the refrigerant used for refrigerators is used. However, when a refrigerant mainly containing the component (A) is used in the above refrigeration cycle, if the refrigerator is lubricated with a commonly used refrigerating machine oil, abrasion resistance is insufficient or stability is insufficient. As a result, long-term stable use was not possible. In particular, this tendency is remarkable when a capillary tube is used as an expansion valve as in a refrigeration cycle of an electric refrigerator or a small air conditioner. The lubricating oil composition for a refrigerator according to the present invention can be used for a refrigerator even when a compression refrigeration cycle having an oil separator and / or a hot gas line is operated using a refrigerant containing the component (A) as a main component. It is effective as a lubricating oil composition.

In the working fluid composition for a refrigerator according to the present invention, the components (A) and (B) are extremely compatible with each other, and particularly, the maximum temperature of the low temperature side separation region is 10 ° C. or less, It is preferably at most 8 ° C, more preferably at most 5 ° C, even more preferably at most 2 ° C. Since the working fluid composition for a refrigerator according to the present invention has a maximum temperature of 10 ° C. or less in the separation region on the low temperature side, phase separation does not occur on the low temperature side during operation of the refrigerator. Enables stable operation of

[0049]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The kinematic viscosity and viscosity index of the base oil and various properties of the lubricating oil were determined according to the following procedures. <Base oil> (1) Kinematic viscosity Kinematic viscosity was measured at a temperature of 40 ° C and 100 ° C using a glass capillary viscometer according to JIS K2283-1983.

<Lubricating oil> (2) Kinematic viscosity Kinematic viscosity at a temperature of 40 ° C was measured using a glass capillary viscometer according to JIS K2283-1983. (3) Compatibility test A predetermined amount of a sample was added to a pressure-resistant glass ampule, and this was connected to a vacuum pipe and a difluoromethane (R32) refrigerant pipe. After the ampoule was degassed under vacuum at room temperature, it was cooled to collect a predetermined amount of difluoromethane (R32) refrigerant. Next, the ampoule is sealed, and in a thermostat, for compatibility on the low temperature side,
By gradually cooling from room temperature to −50 ° C., the temperature at which phase separation started was measured. On the low temperature side, the lower the phase separation temperature, the better.

(4) Lubricity ASTM, D-323, using a closed Falex friction tester
Seizure load was determined according to the three methods. The test conditions were
The oil amount was 300 ml, the refrigerant R32, the pressure was 0.8 MPaG, and the temperature was 50 ° C. (5) Stability (Shield tube test) Lubricant sample 4 was placed in an autoclave with an internal volume of 200 ml.
After adding 0 g, R32 refrigerant gas and copper, aluminum and iron metal catalysts, the autoclave was closed and sealed.
After holding at 5 ° C. for 21 days, the lubricating oil samples were analyzed.

Production Example 1 360.6 g (4.0 mol) of dimethyl carbonate was placed in a 1-liter glass four-necked flask equipped with a stirrer, a thermometer, a nitrogen inlet tube and a distillation head for distillate concentration. 268.8 g (2.0 mol) of dipropylene glycol and 3.9 g (0.02 mol) of a methanol solution of 28% by weight sodium methoxide as a catalyst were put therein, and nitrogen gas was fed at 50 ml / min. And 120
C., heated for 5 hours. When ethanol stopped distilling, heating was stopped and 500 ml of toluene was added. By washing the toluene solution of the obtained product with 300 ml of pure water five times, the washing water no longer showed alkalinity. Then, using a rotary evaporator, the toluene was completely distilled off at 120 ° C. for 30 minutes under reduced pressure of the aspirator, and further at 133 Pa for 30 minutes under reduced pressure of a vacuum pump.

[0053]

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295 g of a polycarbonate of dipropylene glycol (terminal methyl form) represented by the following formula was obtained. Less than,
This is called PC-1. Production Example 2 In Production Example 1, dipropylene glycol 268.8 was used.
Production Example 1 except that 236.3 g (2.0 mol) of 3-methyl-1,5-pentanediol was used instead of g.
In the same way as in

[0055]

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255 g of a 3-methyl-1,5-pentanediol polycarbonate (methyl terminal) represented by the following formula:
I got Hereinafter, this is referred to as PC-2. In Table 1,
The kinematic viscosities and viscosity indices of PC-1 and PC-2 are P
It is shown together with the data of OE-1, POE-2 and POE-3.

[0057]

[Table 1]

(Note) POE-1: pentaerythritol and 2-ethylhexanoic acid / 3,5,5-trimethylhexanoic acid (molar ratio: 0.
5 / 0.5) POE-2: Complete ester of trimethylolpropane and 3,5,5-trimethylhexanoic acid POE-3: Pentaerythritol and 2-ethylhexanoic acid / 2-methylhexanoic acid Complete ester PC- with (molar ratio / 0.5 / 0.5)
1: Polycarbonate obtained in Production Example 1 PC-2: Polycarbonate obtained in Production Example 2 Examples 1 to 5 The base oils (a) and (b) of the types shown in Table 2 were used in the table. The lubricating oils were prepared by mixing at the ratios shown in Table 1, and their properties were determined. The results are shown in Table 2. Comparative Examples 1 to 3 Various properties of a lubricating oil composed of the polyester alone of the type shown in Table 2 were determined. The results are shown in Table 2.

[0059]

[Table 2]

[0060]

[Table 3]

(Note) 1) The weight% at the critical dissolution temperature is [sample / (sample +
R32)] × 100.

[0062]

The lubricating oil composition for refrigerators of the present invention contains a polyester derivative and a polycarbonate oxygen-containing compound, preferably a polycarbonate compound having a specific structure, as base oils. It exhibits excellent compatibility with the refrigerant of formula (1), especially difluoromethane. The lubricating oil composition for a refrigerator and the working fluid composition for a refrigerator of the present invention containing the refrigerant are excellent in abrasion resistance, lubrication characteristics, stability and the like.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example of a compression refrigeration recycle of a “compressor-condenser-expansion valve-evaporator” having an oil separator and a hot gas line.

FIG. 2 is a flowchart showing an example of a compression refrigeration recycle of a “compressor-condenser-expansion valve-evaporator” having an oil separator.

FIG. 3 is a flowchart showing an example of a compression refrigeration recycle of a “compressor-condenser-expansion valve-evaporator” having a hot gas line.

FIG. 4 is a flowchart showing an example of a compression refrigeration recycle of “compressor-condenser-expansion valve-evaporator”.

[Explanation of symbols]

 1: Compressor 2: Condenser 3: Expansion valve 4: Evaporator 5: Oil separator 6: Hot gas line 7: Valve for hot gas line

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10M 105/48 C10M 105/48 107/32 107/32 107/34 107/34 // C10N 20:02 C10N 20:02 30:06 30:06 30:10 30:10 40:30 40:30 F term (reference) 4H104 BB33A BB34A BB36A BB37A BB47A CB13A CB14A EA02A EB08 EB09 EB20 LA03 LA05 PA20

Claims (13)

[Claims] 1. A base oil comprising: (a) kinematic viscosity at 40 ° C.
Degree is 3-500mm ^Two/ S polyester-based derivative;
Based on the total amount of the base oil, (b) kinematic viscosity at 40 ° C. 3 to 5
00mm^Two/ S polycarbonate-based oxygen-containing compound 0.1
Lubricating oil composition for refrigerator including at least 60% by weight and less than 60% by weight
And for a chlorine-free refrigerant having 1 carbon atom,
If contained in the range of 3 to 50% by weight based on the amount,
In any one of the above contents, the two-layer separation temperature on the low temperature side is
Lubricating oil composition for refrigerators having a temperature of 10 ° C. or less
object. 2. The polycarbonate-based oxygen-containing compound as the component (b) is a polycarbonate having two or more carbonate bonds in one molecule, and (a) a compound represented by the general formula (I): (Wherein, Z is a residue obtained by removing a hydroxyl group from an n-valent alcohol having 1 to 12 carbon atoms, R ¹ is a linear or branched alkylene group having 2 to 10 carbon atoms, and R ² is a 1 to 12 carbon atom. A monovalent hydrocarbon group or R ⁴ (O—R ³ ) _p — (where R ⁴
Is a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms, R
³ is a linear or branched alkylene group having 2 to 10 carbon atoms, and p is an integer of 1 to 20. ), A group containing an ether bond, k is an integer of 1 to 30, m is an integer of 1 to 50, and n is an integer of 1 to 6. A) a compound represented by the general formula (II): (Wherein, R ⁵ represents a linear or branched alkylene group having 2 to 10 carbon atoms, q represents an integer of 1 to 20, Z, R ¹ ,
R ² , k, m and n are the same as described above. 2) a compound selected from the group consisting of:
The lubricating oil composition for a refrigerator according to the above. 3. The compound represented by the general formula (I) is a compound represented by the general formula (Ia): (Wherein, R ⁶ is a residue obtained by removing a hydroxyl group from a monohydric alcohol having 1 to 12 carbon atoms, and R ¹ , R ² , k and m are the same as described above), and / or The compound represented by the general formula (II) is represented by the general formula (II-a): (Wherein R ¹ , R ² , R ⁵ , R ⁶ , k, m and q are the same as described above). 4. A compound of the general formula (Ia) and the general formula (II-a)
The lubricating oil composition for a refrigerator according to claim 3, wherein R ¹ is an alkylene group having 2 to 6 carbon atoms. 5. The lubricating oil composition for a refrigerator according to claim 4, wherein R ¹ is an ethylene group or a propylene group. 6. A compound of the general formula (Ia) and the general formula (II-a)
In the above, R ² and / or R ⁶ is a linear or branched alkyl group having 1 to 6 carbon atoms.
The lubricating oil composition for a refrigerator according to the above. 7. The lubricating oil composition for a refrigerator according to claim 1, wherein the polyester derivative is a polyol ester. 8. A base oil having a kinematic viscosity of 7 to 10 at 40 ° C.
Refrigeration lubricant composition according to any one of claims 1 to 7 is of 0 mm ² / s and a viscosity index of 40 or more. 9. The lubricating oil composition for a refrigerator according to claim 1, further comprising an acid scavenger. 10. The method according to claim 1, further comprising at least one additive selected from extreme pressure agents, oil agents and antioxidants.
10. The lubricating oil composition for a refrigerator according to any one of claims to 9. 11. A refrigerator comprising: (A) a chlorine-free refrigerant having 1 carbon atom; and (B) the lubricating oil composition for a refrigerator according to any one of claims 1 to 10. Working fluid composition. 12. The working fluid composition for a refrigerator according to claim 11, comprising the component (A) and the component (B) in a weight ratio of 5:95 to 99: 1. 13. The working fluid composition for a refrigerator according to claim 11, wherein the refrigerant of the component (A) is difluoromethane.