JPH1121575A - Lubricating oil for refrigerating equipment and refrigerating equipment working fluid composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide lubricating oil for refrigerating equipment, excellent in lubricating properties, electrical insulation properties and hydrolysis resistance and capable of coping with a wide-range viscosity grade and a refrigerating equipment working fluid composition exhibiting good solubility of the lubricating oil in a nonchlorinated fluorocarbon in a wide temperature range. SOLUTION: There are provided a lubricating oil for refrigerating equipment, containing at least one compound selected from compound A1 being an adduct of a 2-5C alkylene oxide with a dehydrative condensate of a 4-18C fatty acid at least 50 mol.% of which is constituted by branched carboxylic acids with an amino alcohol having a primary or secondary amino group and compound A2 being a compound derived by replacing the hydroxylic hydrogen atoms of compound A1 by 1-18C alkyl groups or 4-18C acyl groups at least 50 mol.% of which are constituted by branched acyl groups and refrigerating equipment- working fluid containing the above lubricating oil and a non-chlorinated fluorocarbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil used as a refrigerating machine oil for a refrigerator using non-chlorinated freon as a refrigerant, and a refrigerating machine working fluid composition containing the lubricating oil and the non-chlorinated freon. Things.

[0002]

2. Description of the Related Art Conventionally, compression type refrigerators have been provided with CFC-11 (CCl ₃ F, trichloromonofluoromethane), CFC-12 (CCl ₂ F ₂ , dichlorodifluoromethane) and HCFC-22 (CHClF) as refrigerants. _2, monochloro _{difluoromethane), CFC-115 (CF 3} -
Freon refrigerants such as CCIF ₂ and monochloropentafluoroethane are used. However, chlorofluorocarbons such as CFC-12 are subject to regulation as leading to destruction of the ozone layer.
Hydrochlorofluorocarbons such as CFC-22 can also be used at present because of their relatively low ozone layer destruction ability, but regulations on their use have been determined in the medium to long term.

As a substitute for these chlorofluorocarbon and hydrochlorofluorocarbon refrigerants, non-chlorinated chlorofluorocarbon is being used. As an alternative to CFC-12, HFC-134 having similar thermodynamic properties is used.
_{a (CH 2 F-CF 3} , 1,1,1,2- tetrafluoroethane) is likewise Alternative HCFC-22 H
_{FC-32 (CH 2 F 2} , difluoromethane) and H
R-407C (HFC) which is a mixed refrigerant containing FC-125 (1,1,1,2,2-pentafluoroethane)
-32 / HFC-125 / HFC-134a = 23/2
5/52 wt%), R-410A (HFC-32 / HF
C-125 = 50/50 wt%) and R-41OB
(HFC-32 / HFC-125 = 45 / 55wt%)
Is R-502 (CFC-12 / CFC-115 =
48.8 / 51.2 wt%) as an alternative to HFC-1
R-404A (HFC-125 / HFC-143a / H containing 43a (1,1,1-trifluoroethane)
FC-134a = 44/52/4 wt%).

[0004] Further, since the above-mentioned non-chlorofluorocarbon has the disadvantage of warming the earth, oxygen, nitrogen,
Third generation CFCs containing sulfur atoms and having a low tendency to global warming are being developed around the world. As a specific example, 1-trifluoromethoxy-2,2,3,3,3-pentafluoropropane is disclosed in JP-A-7-179386, and pentafluoroethyl-2,2-difluoroethyl is disclosed in JP-A-7-179287. The ether is disclosed in
JP-48306 discloses 1,1-difluoroethyl 2,
2-Difluoroethyl ether is disclosed in JP-A-7-4144.
No. 7,1,2,2-trifluoroethyl 2,2-
Difluoroethyl ether is disclosed in JP-A-7-25803, in which 1,1-difluoroethyl methyl ether is
JP-A-6-293686 discloses methyl 1,1,2,2.
2,3,3-hexafluoropropyl ether is disclosed in JP-A-6-293687, and pentafluoroethyl 2,2,2-trifluoroethyl ether is disclosed in JP-A-6-293687.
JP-A-34754 proposes pentafluoroethylfluoropropyl ethers and JP-A-8-34755 proposes heptafluoropropylfluoroalkyl ethers.

[0005] Although lubricating oil for refrigerators has various required performances, compatibility with a refrigerant is extremely important in terms of lubricating performance of the lubricating oil and system efficiency. However, HFC-
134a and non-chlorinated chlorofluorocarbon refrigerants represented by HFC-32 are refrigerations based on naphthenic mineral oils, paraffinic mineral oils, alkylbenzenes and the like which have been conventionally used as lubricating oils for refrigerators in compression refrigeration systems. It is known that it shows almost no compatibility with mechanical lubricating oils and causes two-layer separation at low and high temperatures. When the two-layer separation occurs, the lubricating oil stays in the condenser or the expander, and the refrigeration efficiency is reduced, or the lubricating oil is not sufficiently supplied to the sliding surface of the compressor, resulting in poor lubrication. This may cause inconveniences such as burn-in of the compressor, and cannot be used in actual use.

[0006] Under such circumstances, various lubricating oils which are compatible with the non-chlorinated Freon refrigerant have been proposed. For example,
Japanese Patent Application Publication No. 2-502385 proposes a polyoxyalkylene glycol ether-based lubricating oil having a specific molecular weight distribution and both terminals having a hydroxyl group. This shows compatibility with HFC-134a in the range of about -40 ° C to + 50 ° C. However, in actual use,
Higher temperature compatibility is required.

On the other hand, HFC-134a is mainly used for home refrigerators and car air conditioners, and the mixed refrigerant containing HFC-32 is mainly used for room air conditioners and industrial refrigerators. In the case of home refrigerators and room air conditioners, most motors for driving compressors are used in refrigerant-refrigerator lubricating oil mixtures. Refrigerator lubricating oils require excellent electrical insulation. You. However, the electrical insulation properties of polyoxyalkylene glycol ethers are remarkably inferior to conventional naphthenic mineral oils and paraffinic mineral oils, and also have high hygroscopicity. Therefore, it is not suitable as lubricating oil for refrigerators such as home refrigerators and room air conditioners.

Japanese Unexamined Patent Publication (Kokai) No. 3-505602 discloses a polyol ester comprising a monohydric carboxylic acid and a polyhydric alcohol and a complex ester comprising a monohydric carboxylic acid, a polyhydric carboxylic acid and a polyhydric alcohol. It has been proposed as a lubricating oil for chlorine-based refrigerants. In the case of these proposed ester compounds, the hygroscopicity is lower than that of polyoxyalkylene glycol ether, and the compatibility with HFC-134a is better in a wider temperature range than that of polyoxyalkylene glycol ether. Also, JP-A-3-1289
As described in JP-A-91-91 and JP-A-3-1288992, the electric greening property also has a volume resistivity of 10 ¹³ to 80 ° C. at 80 ° C.
It has a value of about 10 ¹⁴ Ωcm, which is sufficient for lubricating oil for refrigerators such as freezers and room air conditioners.
However, lubricity is insufficient.

In addition, lubricating oils for refrigerators are required to have various viscosity grades depending on the type of refrigerator, etc. Currently, ISO viscosity grades of VG8 to VG320 are mainly used. For esters,
It has good electrical insulation and can obtain esters of various viscosity grades. However, the ester compounds proposed above are liable to undergo hydrolysis in the presence of water,
There is a concern that the refrigeration system will corrode. In the case of a polyol ester, by using a branched fatty acid as a raw material fatty acid, it is possible to suppress hydrolysis to such an extent that there is no practical problem. However, in the case of the complex ester, the lubricity and H
Although it has good compatibility with FC-134a, it has poor hydrolysis resistance. This is considered to be because most of the commercially available polycarboxylic acids are linear, and the site where the linear polycarboxylic acid is bonded is easily hydrolyzed.

Further, conventionally proposed polyol esters and complex esters are HFC-134a
However, it cannot be said that the compatibility with the mixed refrigerant containing HFC-32 has been sufficiently obtained. JP-A-6-25684 proposes an esterified product of an alkanolamine as a friction modifier for a lubricating oil that imparts storage stability, but it is insufficient in electrical insulation and hydrolysis resistance.

[0011]

From the foregoing, it can be seen that the present invention exhibits excellent compatibility with non-chlorinated Freon refrigerants represented by HFC-134a and HFC-32 over a wide temperature range, Lubricating oil for refrigerators that has excellent lubricity and hydrolytic resistance and that can handle a wide range of viscosity grade values and has excellent lubricating properties, and high performance due to the excellent properties of the lubricating oil for refrigerators It is an object of the present invention to provide a refrigerator working fluid composition.

[0012]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above object, and have found that (a) a fatty acid having 4 to 18 carbon atoms in which a branched carboxylic acid accounts for 50 mol% or more. (C) an alkylene oxide adduct having 2 to 5 carbon atoms of a dehydration condensate of (b) an amino alcohol having a primary or secondary amino group, and hydrogen having a hydroxyl group of the adduct having 1 to 1 carbon atoms. Lubricating oil for refrigerator containing at least one compound selected from compounds substituted by an acyl group having 4 to 18 carbon atoms in which 18 alkyl groups or branched acyl groups occupy 50 mol% or more, and lubrication for refrigerators The present inventors have found that a refrigerator working fluid composition containing oil and non-chlorine-based chlorofluorocarbon as main components can satisfy all of the above-mentioned properties, and have accomplished the present invention.

That is, a first aspect of the present invention is to provide (a) a fatty acid having 4 to 18 carbon atoms in which a branched carboxylic acid accounts for 50 mol% or more, and (b) an amino alcohol having a primary or secondary amino group. (C) an alkylene oxide additive having 2 to 5 carbon atoms (hereinafter, also referred to as compound A1) of a dehydration condensate with
And a compound in which hydrogen of a hydroxyl group of the additive (compound A1) is substituted with an acyl group having 4 to 18 carbon atoms in which an alkyl group or a branched acyl group having 1 to 18 carbon atoms accounts for 50 mol% or more (hereinafter, compound A2). Refrigeration oil containing at least one compound selected from the group consisting of The second present invention is a refrigerator working fluid composition comprising the refrigerating lubricating oil and a non-chlorinated chlorofluorocarbon. In the present specification, the compound A1 and the compound A2 may be collectively referred to as a compound A. Compound A1, compound A
2. In the case of compound A, not only the compound alone,
The concept includes a reaction mixture.

The fatty acid of component (a) used in the present invention has 4 to 18 carbon atoms, preferably 4 to 13, more preferably 4 to 10 carbon atoms. When a fatty acid having 3 or less carbon atoms is used, it has an adverse effect on hydrolysis resistance or deteriorates in corrosion resistance, and when a fatty acid having 19 or more carbon atoms is used, compatibility with a non-chlorinated CFC refrigerant is used. Decrease. The fatty acids include straight-chain fatty acids and branched fatty acids, and among them, the branched fatty acids need to account for at least 50 mol% of the total fatty acids, preferably at least 70 mol%, more preferably at least 70 mol%. It occupies 80 mol% or more, more preferably 90 mol% or more. When the content of the branched monocarboxylic acid is less than 50 mol%, good results cannot be obtained in terms of hydrolysis resistance and compatibility with a non-chlorinated chlorofluorocarbon refrigerant.

Examples of the linear fatty acid include butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid,
Tridecanoic acid, myristic acid, palmitic acid, stearic acid and the like.

Examples of the branched fatty acid include 2-methylpropanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, 2,2-dimethylpropanoic acid, 2-methylpentanoic acid, 3-methylpentanoic acid and 4-methylpentane acid,
2,2-dimethylbutanoic acid, 2-ethylbutanoic acid, 3,
3-dimethylbutanoic acid, 2,2-dimethylpentanoic acid,
2-methyl-2-ethylbutanoic acid, 2,2,3-trimethylbutanoic acid, 2-ethylpentanoic acid, 3-ethylpentanoic acid, 2-methylhexanoic acid, 3-methylhexanoic acid, 4-methylhexanoic acid, 5 -Methylhexanoic acid, isoheptanoic acid, 2-ethylhexanoic acid, 3,5-dimethylhexanoic acid, 2,2-dimethylhexanoic acid, 2-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, 2- Propylpentanoic acid, isooctanoic acid,
2,2-dimethylheptanoic acid, 2,2,4,4-tetramethylpentanoic acid, 3,5,5-trimethylhexanoic acid, 2-methyloctanoic acid, 2-ethylheptanoic acid,
-Methyloctanoic acid, after isononane, neononanoic acid,
2,2-dimethyloctanoic acid, 2-methyl-2-ethylheptanoic acid, 2-methyl-2-propylhexanoic acid, isodecanoic acid, neodecanoic acid, isotridecanoic acid, isomyristic acid, isopalmitic acid, isostearic acid, and the like. Can be

Among such branched fatty acids, those having a branched alkyl group at the carbon atom at the 2-position adjacent to the carboxyl group are preferable for obtaining good hydrolysis resistance. Further, from the viewpoint of compatibility with the non-chlorinated Freon refrigerant, the branched alkyl group of the carboxylic acid is preferably a methyl group or an ethyl group.

The amino alcohol of the component (b) used in the present invention has a primary or secondary amino group.
The alcohol portion of the amino alcohol has 1 to 1 carbon atoms.
0, preferably 1 to 5, more preferably 2 to 4.
Examples of the amino alcohol having a primary amino group include monoethanolamine, 2-amino-1-propanol, and 3
-Amino-1-propanol, monoisopropanol humin, 2-amino-1-butanol and the like.
In the secondary amino alcohol, the alkyl group substituted on the N atom has 1 to 18 carbon atoms, preferably 1 to 1 carbon atoms.
0, more preferably 1-4. Examples of the amino alcohol having a secondary amino group include N-methylethanolamine, N-ethylethanolamine, N-propylethanolamine, Nn-butylethanolamine, and N-methylethanolamine.
t-butylethanolamine, diethanolamine, diisopropanolamine and the like.

In the present invention, the use ratio of the amino alcohol of the component (b) may be arbitrarily selected within a range not to hinder the formation of a dehydration condensate formed with the fatty acid of the component (a). Although it is possible, the amount is generally about 0.2 to 10 mol, preferably about 0.3 to 3 mol, per 1 mol of the fatty acid of the component (a).

Particularly preferred examples of the dehydrated condensate obtained by condensing the component (a) and the component (b) include, for example, 2-
Ethylhexanoic acid, isoheptanoic acid, isononanoic acid, 2
-Dehydration condensates of methylbutanoic acid and the like with monoethanolamine, monoisopropanolamine, diethanolamine, diisopropanolamine and the like.

The alkylene oxide of the component (c) used in the present invention has 2 to 5 carbon atoms. Examples of the alkylene oxide include ethylene oxide, propylene oxide, isobutylene oxide, 1-butene oxide, 2-butene oxide, 1-pentene oxide,
-Methyl-2-butene oxide, glycidol, oxetane, tetrahydrofuran, tetrahydropyran and the like. The alkylene oxide is added to the dehydration condensate by an appropriate method such as single addition, random addition or block addition to obtain Compound A1.

The addition mole number of the alkylene oxide of the component (c) to the dehydration condensate of the fatty acid and the amino alcohol used in the present invention is from 1 to 200, preferably from 1 to 200.
00, more preferably 1 to 80. 2 moles added
If it exceeds 00, the kinematic viscosity of the lubricating oil for a refrigerator becomes too high and cannot be used as a lubricating oil used in a working fluid composition for a refrigerator.

The compound A1 used in the lubricating oil for refrigerators used in the present invention can be obtained by reacting the above components by a conventional method. For example, after the fatty acid and the above amino alcohol are dehydrated and condensed, the alkylene oxide As a second example, after dehydrating and condensing a fatty acid and the amino alcohol, an amino alcoholate of an alkali metal is added to increase the ratio of amidated compounds in the dehydrated condensate, and the active hydrogen of the existing hydroxyl group is increased. To which an alkylene oxide is added, but the production method is not particularly limited.

The compound A1 obtained from the components (a), (b) and (c) has the following properties. (1) Molecular weight: usually 150 to 15000, preferably 20
It is 0-10000, more preferably 300-2000. (2) Hydroxyl group: 1 or 2 hydroxyl groups in the molecule.

In the compound A, the type of the compound A1 and the hydrogen of the hydroxyl group of the compound A1 are converted to an alkyl group having 1 to 18 carbon atoms or a branched acyl group.
And the type of the compound (compound A2) substituted with an acyl group of ~ 18. Compound A2 can be obtained by etherifying compound A1 with an alkyl group using an alkyl halide or the like, or a carboxylic acid having 4 to 18 carbon atoms in which a branched acyl group accounts for 50 mol% or more, or a reactive derivative thereof (for example, , Acid chloride) and the like.

The alkyl group to be etherified has 1 to 18 carbon atoms, preferably 1 to 13, and more preferably 1 to 10. When the alkyl group has 19 or more carbon atoms, the compatibility with the non-chlorinated chlorofluorocarbon refrigerant decreases. The alkyl group includes a straight-chain alkyl group and a branched alkyl group.
It preferably accounts for 0 mol% or more, more preferably 80 mol% or more. The alkyl group branched from the main chain of the branched alkyl group is preferably a methyl group or an ethyl group.

The molecular weight of compound A2 is usually from 160 to 15
000, preferably 200 to 10,000, more preferably 300 to 2,000. In addition, by increasing the substitution rate of the hydroxyl group, a compound having generally low viscosity can be obtained.

After its synthesis, compound A has the following total acid value:
When it has a hydroxyl value and a total amine value, it is preferably used as a lubricating oil. The total acid value is preferably 5 or less, more preferably 1 or less. If it exceeds 5, stability such as hydrolysis resistance will be deteriorated. The hydroxyl value is preferably 550 or less, more preferably 200 or less. If it exceeds 550, the electrical insulation becomes poor and the volume resistivity decreases. The total amine value is preferably 20 or less, more preferably 5 or less. If it exceeds 20, the hydrolysis resistance and the electrical insulation will be low.

In the present invention, Compound A can be used alone as a lubricating oil for refrigerators, and can be used as a naphthenic mineral oil, a paraffinic mineral oil, a poly-α-olefin, an alkylbenzene, an ester, a carbonate, a polyvinyl ether, It can be mixed with other lubricating oils such as fluorinated oils represented by fluorine-containing polyethers and used as lubricating oils for refrigerators for non-chlorinated CFC refrigerants. When the lubricating oil for a refrigerator used in the present invention is mixed with these other lubricating oils, the ratio of the compound A in the mixture may be such as performance such as hydrolysis resistance or compatibility with a non-chlorinated Freon refrigerant. Although it can be used in a proportion within a range not to decrease, generally 10%
% By weight or more, preferably 30% by weight or more, more preferably 50% by weight or more.

The lubricating oil for a refrigerator used in the present invention is 100
Kinematic viscosity at 1 ° C. is from 1 to 150 cSt (10 ⁻⁶ m ² /
s), preferably 1.5 to 100 cSt, more preferably 2 to 50 cSt. If the kinematic viscosity is lower than 1 cSt, the lubricating performance is insufficient, and if the kinematic viscosity is higher than 150 cSt, the compatibility with the non-chlorinated chlorofluorocarbon refrigerant decreases, and neither is preferable. Here, the kinematic viscosity is measured according to JIS K 2283.

The lubricating oil for a refrigerator used in the present invention has a pour point of -30 ° C. or lower, and can be used even at an extremely low temperature. Here, the pour point is measured according to JIS K 2269.

The lubricating oil for refrigerators of the present invention may be added to conventionally known additives for lubricating oils for refrigerators, for example, antioxidants, extreme pressure agents, metal-free materials, in order to further improve its performance. Activators, acid scavengers and the like can be added alone or in combination of several kinds. The amount of these additives is usually 10% with respect to the total amount of lubricating oil for refrigerators.
% By weight, preferably 5% by weight or less.

The second aspect of the present invention is a refrigerator working fluid composition comprising Compound A and non-chlorinated chlorofluorocarbon as main components. In the refrigerator working fluid composition of the present invention, the compounding ratio of the compound A to the non-chlorinated chlorofluorocarbon as the refrigerant is such that the weight ratio of the compound A to the non-chlorinated chlorofluorocarbon is generally 1:99 to 99: 1.
(Weight ratio), preferably 5:95 to 70:30 (weight ratio).

The non-chlorinated chlorofluorocarbon used in the working fluid composition of the refrigerator of the present invention includes HFC-134a and HFC-3.
2. In addition to HFC-125 and HFC-143a, HFC
-152a or the like can be used. Depending on the application, cooling temperature, shape of the cooling device, etc., any of these or a mixture thereof can be appropriately selected.

[0035]

The lubricating oil for refrigerators of the present invention is excellent in lubricity, electrical insulation and hydrolysis resistance, and can correspond to a viscosity grade within a wide viscosity range. And the pour point is-
It is 30 ° C. or less, and can be used even at extremely low temperatures. Further, the lubricating oil for a refrigerator of the present invention and HFC-134
a. The refrigerating machine working fluid composition of the present invention containing a non-chlorinated chlorofluorocarbon represented by HFC-32 and HFC-125 has good dissolution of the non-chlorinated fluorocarbon and the lubricating oil for the refrigerator in a wide temperature range. Shows sex.

[0036]

Next, the present invention will be described in detail with reference to examples. In Examples,% indicates% by weight.

Examples A-1 to A-6, Comparative Examples B-1 to B
-2 Operation Production of dehydration condensate of fatty acid and amino alcohol
Shown in Concrete Tables 1, 2 (a) component of the fatty acid were placed in a four-necked flask equipped with a stirrer, nitrogen-introducing tube, thermometer and condenser with water separator equimolar amino alcohol component (b) The reaction was carried out for 12 hours while removing the distillate water while appropriately measuring the acid value at 160 ° C. under a nitrogen stream, and then the reaction was carried out at the same temperature for 3 hours under reduced pressure (50 mmHg). The acid value at the end of the reaction is 1.0 to 2.0
mg KOH / g.

Operation The above operation
Addition of kylene oxide The alkylene oxide of the component (c) is converted into the alkylene oxide in the molar ratio (%) of the alkylene oxide shown in Tables 1 and 2 by using (a) to (c).
Addition was performed by the methods shown in Tables 1 and 2 in the presence of sodium hydroxide to the dehydrated condensate produced by the operation so that the ratio of the components was as shown in Tables 1 and 2. Then, p with acetic acid
H was neutralized, dehydration was performed, the precipitated salt was separated by filtration, the filtrate was treated with activated clay, and then filtered again. Thus, sample oils A-1 to A-6 and B-1 to B-2 having the total acid value, hydroxyl value and total amine value shown in Tables 1 and 2 were obtained.

Example A-7 Of the terminal hydroxyl groups of the sample oil A-1 obtained in Example A-1,
After 50% methyl etherification, activated clay treatment,
After filtration, a sample oil A-7 having the total acid value, hydroxyl value and total amine value shown in Table 2 was obtained.

Example A-8 Of the terminal hydroxyl groups of the sample oil A-2 obtained in Example A-2,
After esterifying 75%, the mixture was treated with activated clay and filtered to obtain a sample oil A-8 having an acid value, a hydroxyl value and an amine value shown in Table 2.

[0041]

[Table 1]

[0042]

[Table 2]

<Fatty acid of component (a)> bC5: 2-methylbutanoic acid bC6: 2-ethylbutanoic acid bC7: isoheptanoic acid bC8: 2-ethylhexanoic acid bC9: 3,5,5-trimethylhexanoic acid nC12: lauric acid nC18: stearic acid nC20: arachidic acid

<Amino alcohol used for component (b)> ME: monoethanolamine MP: monoisopropanolamine DE: diethanolamine DP: diisopropanolamine

<Alkylene oxide of component (c)> EO: ethylene oxide PO: propylene oxide BO: 1-butene oxide

The performance of the sample oils obtained in Examples A-1 to A-8 and Comparative Examples B-1 to B-2 as lubricating oils for refrigerators was measured in the following manner. Table 3 shows the results. <Kinematic viscosity> Kinematic viscosity was measured at 40 ° C and 100 ° C (JIS K 2283). <Pour point> The pour point was measured. (JIS K 226
9) <Volume resistivity> The volume resistivity was measured at 80 ° C.
(JIS C 2101)

<Compatibility> A 0.6 g sample was mixed with a chlorine-free Freon refrigerant (HFC-134a and R-407C (HFC
-32 / HFC-125 / HFC-134a = 23/2
5/52% by weight)｝ 2.4 g was sealed in a thick Pyrex tube (total length 300 mm, outer diameter 10 mm, inner diameter 6 mm) cooled in an ethanol bath containing dry ice, and heated at a rate of 1 ° C./min. Heating and cooling were performed and the bilayer separation temperatures at high and low temperatures were measured visually in the range of -70 ° C to + 80 ° C.

<Hydrolysis Resistance> 5 ml of a sample whose water content was adjusted to 1,500 ± 300 ppm was injected into a hard glass ampoule having a capacity of 6 ml. After replacing the headspace inside the ampoule with nitrogen and sealing the tube,
Heated for hours. After the test was completed, the sample was opened and the acid value of the sample was measured.

<Wear Resistance (Lubricity)> ASTM D-2
According to 670, HFC-134a was added to the sample at 150.
The Falex abrasion test was performed while blowing at a rate of ml / min. After setting the sample temperature at 100 ° C. and running in a load of 150 pounds for 1 minute, the apparatus was operated under a load of 250 pounds for 2 hours, and the abrasion amount of the pin after the operation was measured.

[0050]

[Table 3]

Tables 2 and 3 also show, as reference examples, the results of measurements on the following samples C-1 to C-4 as commercially available lubricating oils. C-1: polyoxyalkylene glycol (ISO viscosity grade: VG56: propylene oxide adduct of butanol, molecular weight about 1000) C-2: mineral oil-based refrigeration oil (ISO viscosity grade: VG
32) C-3: Alkylbenzene-based refrigeration oil (ISO viscosity grade: VG46) C-4: Ester (ISO viscosity grade: VG46: pentarisritol 2-ethylhexanoic acid tetraester)

From the results shown in Table 3, the lubricating oil for refrigerator used in the present invention has a wide viscosity range and a pour point of -30.degree.
The range showing the compatibility is as follows: HFC-134a is -40 ° C or lower, + 80 ° C or higher on the high temperature side, R-407C is -35 ° C or lower on the low temperature side, and + 70 ° C or higher on the high temperature side. Over a range, and the volume resistivity is 10 ¹³ to 1
It can be seen that the sample had a large value of 0 ¹⁴ Ωcm and a small increase in the acid value of the sample after the hydrolysis resistance test.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10N 30:00 30:02 40:30

Claims (4)

[Claims] 1. A dehydration condensate of (a) a fatty acid having 4 to 18 carbon atoms in which a branched carboxylic acid accounts for 50 mol% or more and (b) an amino alcohol having a primary or secondary amino group. c) An alkylene oxide adduct having 2 to 5 carbon atoms (compound A1) and an alkyl group having 1 to 18 carbon atoms or a branched acyl group occupying 50 mol% or more of hydrogen of a hydroxyl group of the adduct (compound A1). A lubricating oil for a refrigerator containing at least one compound selected from compounds substituted with an acyl group having 4 to 18 carbon atoms (compound A2). 2. A kinematic viscosity at 100 ° C. of 1 to 150 cSt.
The lubricating oil for a refrigerator according to claim 1, wherein the lubricating oil is (10 ^-6 m ² / s). 3. A refrigerant working fluid composition containing the lubricating oil according to claim 1 and non-chlorofluorocarbon. 4. The non-chlorinated chlorofluorocarbon is 1,1,1,2-tetrafluoroethane, difluoromethane, 1,1,1,1.
The refrigerator working fluid composition according to claim 3, which is at least one selected from 2,2-pentafluoroethane, 1,1,1-trifluoroethane, and 1,1-difluoroethane.