JPH11310775A - Fluid composition for refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid compsn. for refrigerators which is suitable when a 3-5C fluorohydrocarbon is used. SOLUTION: This fluid compsn. contains (A) a refrigerant contg. at least one 3-5C fluorohydrocarbon and (B) a base oil comprising at least one oxygen- contg. synthetic oil selected from among (a) polyvinyl ethers, (b) polyol esters, and (c) polyalkylene glycols and having a kinematic viscosity at 40 deg.C of 5-500 mm<2> /s and a total acid value of 0.1 mgKOH/g or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a fluid composition for a refrigerator, and more particularly, to a fluid composition for a refrigerator using HFC-254fa or the like as a refrigerant.

[0002]

2. Description of the Related Art At present, centrifugal chillers are used for large-scale air conditioners in department stores, offices, hotels, theaters, etc. because of their large refrigerating capacity. As the refrigerant, HCFC-123 (1,1-dichloro-2,2,2-trifluoroethane), which has a small stratospheric ozone depletion effect, is used, but the HCFC refrigerant will be totally abolished in the future. Therefore, as a substitute refrigerant for HCFC-123, a fluorinated hydrocarbon containing 3 to 5 carbon atoms and containing no chlorine, such as HFC-245fa (1,1,1,3,3-pentafluoropropane) that does not destroy the ozone layer. Compounds are being investigated. However, at present, no corresponding refrigerating machine oil has been found.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above point of view, and provides a fluid composition for a refrigerator suitable for using a fluorinated hydrocarbon having 3 to 5 carbon atoms as a refrigerant. The purpose is to do so.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above object of the present invention can be effectively achieved by using a specific oxygen-containing synthetic oil as a base oil. The present invention has been completed. That is, the present invention is selected from (A) a refrigerant containing at least one fluorocarbon having 3 to 5 carbon atoms, and (B) (a) polyvinyl ether, (b) polyol ester, and (c) polyalkylene glycol. A kinematic viscosity at 40 ° C. of at least one oxygen-containing synthetic oil of 5 to 500 mm ² / s,
A fluid composition for a refrigerator, comprising: a base oil having a total acid value of 0.1 mgKOH / g or less.

[0005]

Embodiments of the present invention will be described below. First, in the refrigerator fluid composition of the present invention, a fluorinated hydrocarbon having 3 to 5 carbon atoms is used as the component (A) refrigerant. Above all, in terms of vapor pressure, carbon number 3
Are preferably used, for example, HFC-236ca
(1,1,2,2,3,3-hexafluoropropane), HFC-236cb (1,1,1,2,2,3-
Hexafluoropropane), HFC-245ca (1,
1,2,2-tetrafluoropropane), HFC-24
5fa (1,1,1,3,3-pentafluoropropane), HFC-227ea (1,1,1,2,3,3,3)
3-heptafluoropropane), HFC-227ca
(1,1,1,2,2,3,3-heptafluoropropane), HFC-236ea (1,1,1,2,3,3-
Hexafluoropropane), HFC-236fa (1,
1,1,3,3,3-hexafluoropropane) and the like. Among those having 3 carbon atoms, HFC-245fa is preferred from the viewpoint of safety.

Next, in the fluid composition for a refrigerator according to the present invention, at least one kind selected from (a) polyvinyl ether, (b) polyol ester, and (c) polyalkylene glycol is used as the base oil of component (B). An oxygen-containing synthetic oil is used. As the polyvinyl ether of the above (a), for example, the general formula (I)

[0007]

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(Wherein, R ^{1 to} R ³ each represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, which may be the same or different, and R ⁴ represents a 1 to 10 carbon atom. A divalent hydrocarbon group or a divalent ether-bonded oxygen-containing hydrocarbon group having 2 to 20 carbon atoms, R ⁵ represents a hydrocarbon group having 1 to 20 carbon atoms, and a represents a number having an average value of 0 to 10 , R ^1-
R ⁵ may be the same as or different from each other in each structural unit, also in the case where R ⁴ O is plural, plural R ⁴ O may be the same or different. And a polyvinyl ether-based compound (1) having a structural unit represented by formula (1).
Further, a structural unit represented by the above general formula (I) and a structural unit represented by the following general formula (II)

[0009]

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(Wherein, R ^{6 to} R ⁹ each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, which may be the same or different, and R ^{6 to} R ⁹ have the same structure A polyvinyl ether compound (2) composed of a block or a random copolymer having a structural unit represented by formula (1) may be the same or different for each unit. Further, a polyvinyl ether compound (3) comprising a mixture of the above polyvinyl ether compound (1) and the polyvinyl ether compound (2) can also be used.

In the general formula (I), R ^{1 to} R ³ each represent a hydrogen atom or a hydrocarbon group having 1 to 8, preferably 1 to 4 carbon atoms. Here, the hydrocarbon group is specifically a methyl group, an ethyl group, an n-propyl group, an isopropyl group, various butyl groups, various pentyl groups, various hexyl groups,
Cycloalkyl groups such as various heptyl groups, various octyl alkyl groups, cyclopentyl groups, cyclohexyl groups, various methylcyclohexyl groups, various ethylcyclohexyl groups, various dimethylcyclohexyl groups, phenyl groups,
Examples include various methylphenyl groups, various ethylphenyl groups, aryl groups of various dimethylphenyl groups, benzyl groups, various phenylethyl groups, and arylalkyl groups of various methylbenzyl groups. Note that these R ^{1 to} R ³
Is particularly preferably a hydrogen atom.

On the other hand, R ⁴ in the general formula (I) has 1 carbon atom.
A divalent hydrocarbon group having 10 to 10, preferably 2 to 10 or a divalent ether-bonded oxygen-containing hydrocarbon group having 2 to 20 carbon atoms, wherein a divalent hydrocarbon group having 1 to 10 carbon atoms Specifically, methylene group; ethylene group; phenylethylene group; 1,2-propylene group; 2-phenyl-1,2
-Propylene group; 1,3-propylene group; various butylene groups; various pentylene groups; various hexylene groups; various heptylene groups; various octylene groups; various nonylene groups; divalent aliphatic groups of various decylene groups; cyclohexane; methylcyclohexane Alicyclic groups having two binding sites to an alicyclic hydrocarbon such as ethylcyclohexane; dimethylcyclohexane; propylcyclohexane; various phenylene groups; various methylphenylene groups; various ethylphenylene groups; various dimethylphenylene groups; various naphthylene Aromatic hydrocarbon group such as a group, toluene; xylene; an alkyl aromatic group having a monovalent bonding site in each of an alkyl group portion and an aromatic portion of an alkyl aromatic hydrocarbon such as ethylbenzene, xylene; diethylbenzene, etc. Polyalkyl aromatic carbonization An alkyl aromatic group having a bonding site in the alkyl group moiety containing can be mentioned.
Among these, an aliphatic group having 2 to 4 carbon atoms is particularly preferred.

Specific examples of the divalent ether-bonded oxygen-containing hydrocarbon group having 2 to 20 carbon atoms include a methoxymethylene group; a methoxyethylene group; a methoxymethylethylene group; a 1,1-bismethoxymethylethylene group; 1,2-
Bismethoxymethylethylene group; ethoxymethylethylene group; (2-methoxyethoxy) methylethylene group;
A (1-methyl-2-methoxy) methylethylene group can be preferably exemplified. In the general formula (I), a represents the number of repetitions of R ⁴ O, and the average value thereof is 0 to 1
It is a number in the range of 0, preferably 0-5. When R ⁴ O is plural, plural R ⁴ O may be the same or different.

Further, R ⁵ in the general formula (I) represents a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, specifically, a methyl group, an ethyl group, n-propyl group, isopropyl group, various butyl groups,
Various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, various decyl group alkyl groups, cyclopentyl groups, cyclohexyl groups, various methylcyclohexyl groups, various ethylcyclohexyl groups, various propylcyclohexyl groups, various dimethyl groups Aryl groups such as cycloalkyl groups such as cyclohexyl groups, phenyl groups, various methylphenyl groups, various ethylphenyl groups, various dimethylphenyl groups, various propylphenyl groups, various trimethylphenyl groups, various butylphenyl groups, various naphthyl groups, and benzyl groups Groups, various phenylethyl groups, various methylbenzyl groups, various phenylpropyl groups, arylalkyl groups of various phenylbutyl groups, and the like.

The polyvinyl ether compound (1)
Has a structural unit represented by the general formula (I), and the number of repetitions (degree of polymerization) may be appropriately selected according to a desired kinematic viscosity. The polyvinyl ether compound has a carbon / oxygen molar ratio of 4.2 to 7.0.
Those in the range of 0 are preferred. If the molar ratio is less than 4.2, the hygroscopicity may increase, and if it exceeds 7.0, the compatibility with the refrigerant may decrease.

Further, a polyvinyl ether compound (2)
Is a block or a random copolymer having a structural unit represented by the general formula (I) and a structural unit represented by the general formula (II), and in the general formula (II) , R ^{6 to} R ⁹ each represent a hydrogen atom or a carbon atom 1
Represent up to 20 hydrocarbon groups, which may be the same or different. Examples of the hydrocarbon group having 1 to 20 carbon atoms may include the same as those exemplified in the description of R ⁵ in the above general formula (I).
Note that R ^{6 to} R ⁹ may be the same or different for each structural unit.

The degree of polymerization of the polyvinyl ether compound (2) comprising a block or random copolymer having the structural unit represented by the general formula (I) and the structural unit represented by the general formula (II) is as follows: What is necessary is just to select suitably according to the desired kinematic viscosity. In addition, this polyvinyl ether compound,
Those having a carbon / oxygen molar ratio in the range of 4.2 to 7.0 are preferred. If the molar ratio is less than 4.2, the hygroscopicity may increase, and if it exceeds 7.0, the compatibility with the refrigerant may decrease.

Further, a polyvinyl ether compound (3)
Is a mixture of the polyvinyl ether-based compound (1) and the polyvinyl ether-based compound (2), but the mixing ratio is not particularly limited. The polyvinyl ether-based compounds (1) and (2) used in the present invention are obtained by polymerization of the corresponding vinyl ether-based monomer, and copolymerization of the corresponding hydrocarbon monomer having an olefinic double bond with the corresponding vinyl ether-based monomer. It can be produced by polymerization. The vinyl ether monomer that can be used here is represented by the following general formula (III)

[0019]

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(Wherein, R ^{1 to} R ⁵ and a are the same as described above). As the vinyl ether-based monomer, there are various kinds corresponding to the polyvinyl ether-based compounds (1) and (2), for example, vinyl methyl ether; vinyl ethyl ether; vinyl-n-propyl ether; vinyl-isopropyl ether; Vinyl-n-butyl ether; vinyl-isobutyl ether; vinyl-sec-butyl ether; vinyl-
tert-butyl ether; vinyl-n-pentyl ether; vinyl-n-hexyl ether; vinyl-2-methoxyethyl ether; vinyl-2-ethoxyethyl ether; vinyl-2-methoxy-1-methylethyl ether; Methoxy-2-methylethyl ether; vinyl-3,6-dioxaheptyl ether; vinyl-3,6,9-trioxadecyl ether; vinyl-
1,4-dimethyl-3,6-dioxaheptyl ether; vinyl-1,4,7-trimethyl-3,6,9-trioxadecyl ether; vinyl-2,6-dioxa-
4-heptyl ether; vinyl-2,6,9-trioxa-4-decyl ether; 1-methoxypropene;
Ethoxypropene; 1-n-propoxypropene; 1-
Isopropoxypropene; 1-n-butoxypropene;
1-isobutoxypropene; 1-sec-butoxypropene; 1-tert-butoxypropene; 2-methoxypropene; 2-ethoxypropene; 2-n-propoxypropene; 2-isopropoxypropene; 2-n-butoxypropene; 2-isobutoxypropene; 2-sec
-Butoxypropene; 2-tert-butoxypropene; 1-methoxy-1-butene; 1-ethoxy-1-butene; 1-n-propoxy-1-butene; 1-isopropoxy-1-butene; Butoxy-1-butene;
1-isobutoxy-1-butene; 1-sec-butoxy-1-butene; 1-tert-butoxy-1-butene;
2-methoxy-1-butene; 2-ethoxy-1-butene; 2-n-propoxy-1-butene; 2-isopropoxy-1-butene; 2-n-butoxy-1-butene;
-Isobutoxy-1-butene; 2-sec-butoxy-
1-butene; 2-tert-butoxy-1-butene; 2
-Methoxy-2-butene; 2-ethoxy-2-butene;
2-n-propoxy-2-butene; 2-isopropoxy-2-butene; 2-n-butoxy-2-butene; 2-isobutoxy-2-butene; 2-sec-butoxy-2-
Butene; 2-tert-butoxy-2-butene; These vinyl ether monomers can be produced by a known method. The hydrocarbon monomer having an olefinic double bond is represented by the following general formula (I
V)

[0021]

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Wherein R ^{6 to} R ⁹ are the same as described above. Examples of the monomer include ethylene, propylene, various butenes, various pentenes, various hexenes, various heptene, Examples include various octenes, diisobutylene, triisobutylene, styrene, and various alkyl-substituted styrenes. As the polyvinyl ether compound used in the present invention, those having the following terminal structure, that is, one terminal of which is represented by the general formula (V) or (VI)

[0023]

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[0024] (wherein, R ¹⁰ to R ¹² each represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, R ¹⁰ to R ¹² may be the same as or different from each other, R ¹⁵ to R ¹⁸ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and R ^{15 to} R ¹⁸ may be the same or different from each other, and R ¹³ is a divalent hydrocarbon group having 1 to 10 carbon atoms. Or a divalent ether-linked oxygen-containing hydrocarbon group having 2 to 20 carbon atoms,
R ¹⁴ represents the number of hydrocarbon groups having 1 to 20 carbon atoms, b has an average value 0, when R ¹³ O is plural, plural R ¹³ O may be the same or different . ),
And the remaining terminal is represented by the following general formula (VII) or (VIII)

[0025]

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[0026] (wherein, R ¹⁹ to R ²¹ each represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, R ¹⁹ to R ²¹ may be the same as or different from each other, R ²⁴ to R ²⁷ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and R ^{24 to} R ²⁷ may be the same or different, and R ²² is a divalent hydrocarbon group having 1 to 10 carbon atoms. Or a divalent ether-linked oxygen-containing hydrocarbon group having 2 to 20 carbon atoms,
R ²³ represents the number of hydrocarbon groups having 1 to 20 carbon atoms, c is the average value 0, when R ²² O is plural, plural R ²² O may be the same or different . ) And one end thereof is represented by the above general formula (V) or (VI), and the other end is represented by the following general formula (IX)

[0027]

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(Wherein R ^{28 to} R ³⁰ each represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, which may be the same or different from each other). Are preferred. Among such polyvinyl ether compounds, the following compounds are particularly suitable as the base oil of the fluid composition for refrigerators of the present invention.

(1) One terminal of which is represented by the general formula (V) or
(VI), and the remaining terminal is represented by the general formula (VII) or
Having a structure represented by (VIII), wherein
R¹~ R ^ThreeAre both hydrogen atoms, a is a number from 0 to 4, R^FourBut charcoal
A divalent hydrocarbon group having a prime number of 2 to 4 and R^FiveHas 1-2 carbon atoms
A hydrocarbon group of 0. (2) having only the structural unit represented by the general formula (I)
Wherein one end thereof is represented by the general formula (V),
And the remaining terminal has a structure represented by the general formula (VII),
R in the general formula (I)¹~ R^ThreeAre both hydrogen atoms and a is
A number from 0 to 4, R^FourIs a divalent hydrocarbon group having 2 to 4 carbon atoms and
And R^FiveIs a hydrocarbon group having 1 to 20 carbon atoms.

(3) One of the terminals is represented by the general formula (V) or
(VI), and the remaining terminal is represented by the general formula (IX).
Having a structure represented by the general formula (I):¹~ R^ThreeIs
A hydrogen atom, a is a number from 0 to 4, R^FourIs two to four carbon atoms
Divalent hydrocarbon groups and R^FiveIs a hydrocarbon group having 1 to 20 carbon atoms
What is. (4) having only the structural unit represented by the general formula (I)
Wherein one end thereof is represented by the general formula (V),
And the other end has a structure represented by the general formula (VIII).
And R in the general formula (I)¹~ R^ThreeAre both hydrogen atoms,
a is a number from 0 to 4, R ^FourIs a divalent hydrocarbon having 2 to 4 carbon atoms
Group and R^FiveIs a hydrocarbon group having 1 to 20 carbon atoms.
In the present invention, the compound represented by the general formula (I) is used.
Having a structural unit, one end of which is represented by the general formula (V)
And the remaining terminal is represented by the general formula (X)

[0031]

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(Wherein, R ^{31 to} R ³³ each represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, which may be the same or different, and R ³⁴ and R ³⁶ each represent a carbon atom Represents a divalent hydrocarbon group having 2 to 10 carbon atoms, which may be the same or different; R ³⁵ and R ³⁷ each represent a hydrocarbon group having 1 to 10 carbon atoms; And d and e each have an average value of 0 to 10, each of which may be the same or different, and when there are a plurality of R ³⁴ O, a plurality of R ³⁴ O is may be the same or different, may use polyvinyl ether compound having a structure more R ³⁶ O represented by may be the same or different.) If there is more than one R ³⁶ O can do. Further, in the present invention, the following general formula (XI) or (XII)

[0033]

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(Wherein R ³⁸ represents a hydrocarbon group having 1 to 8 carbon atoms), and has a weight average molecular weight of 300 to 3,000 (preferably 300 to 2,000).
000), and one end is represented by the general formula (XIII) or (XIV)

[0035]

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(Wherein, R ³⁹ represents an alkyl group having 1 to 3 carbon atoms, and R ⁴⁰ represents a hydrocarbon group having 1 to 8 carbon atoms). A polyvinyl ether compound composed of a polymer can also be used. In addition, the following general formula (XV)

[0037]

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(Wherein R ⁴¹ represents a hydrocarbon group having or not having an ether bond in the molecule having 1 to 3 carbon atoms), and a structural unit (A) represented by the following general formula (XVI)

[0039]

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(Wherein R ⁴² represents a hydrocarbon group having or not having an ether bond in a molecule having 3 to 20 carbon atoms). A polyvinyl ether compound having a structural unit (B) represented by the following formula: However, R ^{41 of} the structural unit (A) and R ⁴² of the structural unit (B) are not the same]. R
⁴¹ is an alkyl group having 1 to 3 carbon atoms, and R ⁴² is 3 to 20 carbon atoms.
The case of an alkyl group of is more preferably used, particularly a case of a polyvinyl ether compound in which R ⁴¹ is a methyl group or an ethyl group, and R ⁴² is an alkyl group having 3 to 6 carbon atoms,
Among them, a polyvinyl ether compound in which R ⁴¹ is an ethyl group and R ⁴² is an isobutyl group is most suitable. In this case, the ratio of the structural unit (A) to the structural unit (B) is 95: 5 in molar ratio.
５０50: 50 is preferable, and 95: 5 to 70:30.
Is more preferable.

The polyvinyl ether compound can be produced by subjecting the above-mentioned monomer to radical polymerization, cationic polymerization, radiation polymerization or the like. For example, a vinyl ether-based monomer is polymerized by the following method to obtain a polymer having a desired viscosity. For the initiation of the polymerization, it is possible to use a combination of an adduct of a carboxylic acid with water, an alcohol, a phenol, an acetal or a vinyl ether with a Bronsted acid, Lewis acid or organometallic compound. it can.

Examples of Bronsted acids include hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, nitric acid, sulfuric acid, trichloroacetic acid, trifluoroacetic acid and the like. Examples of the Lewis acids include boron trifluoride, aluminum trichloride, aluminum tribromide, tin tetrachloride, zinc dichloride, ferric chloride and the like. Among these Lewis acids, especially boron trifluoride Is preferred. Examples of the organic metal compound include diethyl aluminum chloride, ethyl aluminum chloride, diethyl zinc, and the like.

Water, alcohols,
Adducts of phenols, acetals or vinyl ethers with carboxylic acids can be selected arbitrarily. Here, examples of the alcohols include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, and te.
Examples include saturated aliphatic alcohols having 1 to 20 carbon atoms such as rt-butanol, various pentanols, various hexanols, various heptanols, various octanols, and unsaturated aliphatic alcohols having 3 to 10 carbon atoms such as allyl alcohol.

When an adduct of a vinyl ether and a carboxylic acid is used, examples of the carboxylic acid include acetic acid; propionic acid; n-butyric acid; isobutyric acid; n-valeric acid; isovaleric acid; 2-methylbutyric acid; Acid; n-caproic acid;
2,2-dimethylbutyric acid; 2-methylvaleric acid; 3-methylvaleric acid; 4-methylvaleric acid; enanthic acid; 2-methylcaproic acid; caprylic acid;
-Propylvaleric acid; n-nonanoic acid; 3,5,5-trimethylcaproic acid; caprylic acid; undecanoic acid and the like.

The vinyl ethers may be the same as or different from those used for the polymerization. The adduct of the vinyl ether and the carboxylic acid is obtained by mixing the two and reacting at a temperature of about 0 to 100 ° C., separated by distillation or the like, and used for the reaction, but separated as it is. It can also be used for the reaction without any.

The polymerization initiation terminal of the polymer is one in which hydrogen is bonded when water, alcohols or phenols are used, and one of the alkoxy groups is eliminated from hydrogen or the used acetal when acetal is used. Becomes When an adduct of a vinyl ether and a carboxylic acid is used, an alkylcarbonyloxy group derived from the carboxylic acid moiety is eliminated from the adduct of the vinyl ether and the carboxylic acid.

On the other hand, when water, alcohols, phenols, and acetals are used, the terminating terminals are acetal, olefin, or aldehyde. In the case of an adduct of a vinyl ether and a carboxylic acid, a carboxylic acid ester of hemiacetal is obtained. The terminal of the polymer thus obtained can be converted to a desired group by a known method. Examples of the desired group include residues of saturated hydrocarbons, ethers, alcohols, ketones, nitriles, amides and the like, and preferred are residues of saturated hydrocarbons, ethers and alcohols.

The polymerization of the vinyl ether monomer represented by the general formula (III) depends on the type of the starting material and the initiator.
It can start between 80-150 ° C., usually -8
It can be performed at a temperature in the range of 0 to 50 ° C. The polymerization reaction is completed in about 10 seconds to 10 hours after the start of the reaction. Regarding the control of the molecular weight in the polymerization reaction, the amount of water, alcohols, phenols, acetals, and adducts of vinyl ethers and carboxylic acids is increased with respect to the vinyl ether monomer represented by the general formula (III). By doing so, a polymer having a low average molecular weight can be obtained. Further, by increasing the amount of the Bronsted acids or Lewis acids, a polymer having a low average molecular weight can be obtained.

This polymerization reaction is usually performed in the presence of a solvent. The solvent is not particularly limited as long as it dissolves a required amount of a reaction raw material and is inert to the reaction.
For example, hydrocarbons such as hexane, benzene, and toluene, and ethyl ether, 1,2-dimethoxyethane,
An ether solvent such as tetrahydrofuran can be suitably used. This polymerization reaction can be stopped by adding an alkali. After the completion of the polymerization reaction, the desired polyvinyl ether compound having the structural unit represented by the general formula (I) can be obtained by performing a usual separation / purification method as required.

The polyvinyl ether compound used in the present invention has a carbon / oxygen molar ratio of 4.2 to 7.0 as described above.
0 is preferable, but the carbon /
By adjusting the oxygen molar ratio, a polymer having the molar ratio in the above range can be produced. That is, if the ratio of the monomer having a large carbon / oxygen molar ratio is large,
A polymer having a large carbon / oxygen molar ratio can be obtained, and if the ratio of the monomer having a small carbon / oxygen molar ratio is large, the carbon / oxygen molar ratio can be increased.
A polymer having a small oxygen molar ratio is obtained.

Further, as shown in the polymerization method of the vinyl ether monomer, water, alcohols, phenols, acetals, adducts of vinyl ethers with carboxylic acids used as initiators, and combinations of monomers with monomers. Is also possible. Carbon / monomer
If an alcohol or phenol having a high oxygen molar ratio is used as the initiator, a polymer having a higher carbon / oxygen molar ratio than the starting monomer can be obtained. By using these, a polymer having a smaller carbon / oxygen molar ratio than the starting monomer can be obtained.

Further, when a vinyl ether monomer and a hydrocarbon monomer having an olefinic double bond are copolymerized, a polymer having a carbon / oxygen molar ratio larger than that of the vinyl ether monomer can be obtained. The proportion can be adjusted by the proportion of the hydrocarbon monomer having an olefinic double bond and the number of carbon atoms thereof.

Examples of the polyol ester (b) include a carboxylic acid ester of a polyvalent hydroxy compound containing at least two hydroxyl groups.
II) R ⁴³ [OCOR ⁴⁴ ] _f (XVII) (wherein R ⁴³ is a hydrocarbon group, R ⁴⁴ is a hydrogen atom or a hydrocarbon group having 1 to 22 carbon atoms, and f is an integer of 2 to 6) And a plurality of —OCOR ⁴⁴ may be the same or different.).

In the above formula (XVII), R ⁴³ represents a hydrocarbon group, which may be linear or branched, and preferably an alkyl group having 2 to 10 carbon atoms. R ⁴⁴ is a hydrogen atom or a hydrocarbon group having 1 to 22 carbon atoms, preferably an alkyl group having 2 to 16 carbon atoms. The polyol ester represented by the general formula (XVII) has a general formula (XV
III) R ⁴³ (OH) _f ... (XVIII) (wherein R ⁴³ and f are the same as described above) and a general formula (XIX) R ⁴⁴ COOH. (XIX) (wherein R ⁴⁴ is the same as defined above), and can be obtained by reacting with a reactive derivative such as a carboxylic acid or an ester or an acid halide thereof.

The polyhydric alcohol represented by the general formula (XVIII) is preferably, for example, ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, glycerin, pentaerythritol.
Examples thereof include dipentaerythritol and sorbitol. On the other hand, the carboxylic acid represented by (XIX) is preferably, for example, propionic acid, butyric acid, pivalic acid, valeric acid, caproic acid, heptanoic acid, 3-methylhexanoic acid, 2-ethylhexanoic acid, caprylic acid, Examples include pelargonic acid, decanoic acid, lauric acid, myristic acid, and palmitic acid.

As the polyalkylene glycol of the above (c), the following general formula (XX): R ⁴⁵ -[(OR ⁴⁶ ) _g -OR ⁴⁷ ] _h (XX) (where R ⁴⁵ is a hydrogen atom An alkyl group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms or an aliphatic hydrocarbon group having 1 to 10 carbon atoms having 2 to 6 bonding portions, and R ⁴⁶ is an alkylene group having 2 to 4 carbon atoms. , R ⁴⁷ is a hydrogen atom, having 1 to 1 carbon atoms
0 alkyl group or acyl group having 2 to 10 carbon atoms, h is 1
G is an integer of 6 to 80, and g is an integer of 6 to 80. )).

In the above formula (XX), the alkyl group at R ⁴⁵ and R ⁴⁷ may be any of linear, branched or cyclic. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, various butyl groups, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, and various decyl groups. , Cyclopentyl group, cyclohexyl group and the like. If the carbon number of the alkyl group exceeds 10, the compatibility with the refrigerant is reduced, and phase separation may occur. The preferred alkyl group has 1 to 6 carbon atoms.

The alkyl group portion of the acyl group in R ⁴⁵ and R ⁴⁷ may be linear, branched or cyclic. Specific examples of the alkyl group portion of the acyl group include those having 1 to 9 carbon atoms mentioned as specific examples of the above alkyl group.
Various groups can be similarly mentioned. If the number of carbon atoms in the acyl group exceeds 10, the compatibility with the refrigerant may be reduced and phase separation may occur. A preferred acyl group has 2 carbon atoms.
~ 6.

R⁴⁵And R⁴⁷Is an alkyl group or
When it is an acyl group, R⁴⁵And R ⁴⁷Identical to each other
May also be different. When h is 2 or more,
Multiple Rs in one molecule⁴⁷May be the same or different.
R⁴⁵Having 1 to 10 carbon atoms having 2 to 6 binding sites
If it is an aliphatic hydrocarbon group, this aliphatic hydrocarbon group
Or a ring. Two binding sites
As the aliphatic hydrocarbon group having, for example, an ethylene group,
Propylene, butylene, pentylene, hexylene
Group, heptylene group, octylene group, nonylene group, decile
Group, cyclopentylene group, cyclohexylene group, etc.
Can be mentioned. Also has 3 to 6 binding sites
As the aliphatic hydrocarbon group, for example, trimethylol pro
Bread, glycerin, pentaerythritol, sorbitol
1,2,3-trihydroxycyclohexane; 1,
Polyvalent alcohols such as 3,5-trihydroxycyclohexane
Residues obtained by removing hydroxyl groups from coal may be mentioned.

If the aliphatic hydrocarbon group has more than 10 carbon atoms, the compatibility with the refrigerant may be reduced, and phase separation may occur. The preferred number of carbon atoms is 2 to 6. The general formula (X
R ^{46 in} X) is an alkylene group having 2 to 4 carbon atoms, and examples of the oxyalkylene group of the repeating unit include an oxyethylene group, an oxypropylene group, and an oxybutylene group. The oxyalkylene groups in one molecule may be the same or may contain two or more oxyalkylene groups, but those containing at least oxypropylene units in one molecule are preferred, and particularly the oxyalkylene units Those containing at least 50 mol% of oxypropylene units are preferred. When two or more oxyalkylene groups are contained, they may be random copolymers or block copolymers.

H in the general formula (XX) is an integer of 1 to 6, and is determined according to the number of R ⁴⁵ binding sites. For example, R
If ⁴⁵ is an alkyl group or an acyl group, h is 1, R ⁴⁵
Is an aliphatic hydrocarbon group having 2, 3, 4, 5 and 6 bonding sites, h is 2, 3, 4, 5 and 6 respectively
Becomes Further, g is a number such that the average value of g × h is 6 to 80. If the average value of g × h is out of the above range, the object of the present invention may not be sufficiently achieved.

The polyalkylene glycol represented by the general formula (XX) includes a polyalkylene glycol having a hydroxyl group at a terminal, and the content of the hydroxyl group is 50 mol% or less based on all terminal groups. If it is such a ratio, it can be suitably used even if it is contained.
If the content of the hydroxyl group exceeds 50 mol%, the hygroscopicity may increase, and the viscosity index may decrease.

The polyalkylene glycol represented by the general formula (XX) includes polyoxypropylene glycol dimethyl ether, polyoxyethylene polyoxypropylene glycol monomethyl ether, polyoxyethylene polyoxypropylene glycol dimethyl ether,
Polyoxyethylene polyoxypropylene glycol monobutyl ether, polyoxypropylene glycol monobutyl ether, and polyoxypropylene glycol diacetate are preferred in terms of economy and effect.

The above-described base oil of the oxygen-containing synthetic oil has a kinematic viscosity at 40 ° C of 5 to 500 mm ² / s (preferably 10 to 500 mm ² / s).
３００300 mm ² / s), the total acid value is 0.1 mg KOH / g
It must be: If the viscosity is too high, the compatibility will decrease and the power loss will increase. On the other hand, if the viscosity is too low, poor lubrication and seal leakage will occur, which is not preferable. When the total acid value exceeds 0.1 mgKOH / g,
It is not preferable because it corrodes metal materials and causes deterioration of oil.

Further, mineral oil or poly-α-olefin synthetic oil (PAO) may be mixed with the above-mentioned oxygen-containing synthetic oil as a base oil so that the two-layer separation temperature with the refrigerant is 5 ° C. or less. Good. The base oil of the fluid composition for a refrigerator according to the present invention may contain, if necessary, various known additives, for example, a lubricity improver such as a phosphate ester or a phosphite ester; a phenolic antioxidant; Acid scavengers such as epoxy compounds such as phenylglycidyl ether, cyclohexene oxide and epoxidized soybean oil; copper deactivators such as benzotriazole and benzotriazole; defoaming agents such as silicone oil and fluorinated silicone oil And the like can be appropriately compounded in the range of 0.01 to 10% by weight, preferably 0.1 to 5% by weight, respectively. The standard of the amount is the sum of the base oil and the additive. In the fluid composition for a refrigerator according to the present invention, the mixing ratio of the refrigerant and the base oil (refrigerant / base oil (weight ratio)) is 0.1 or more, and preferably 1 or more.

[0066]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. [Examples 1 to 8 and Comparative Examples 1 and 2] A two-layer separation test and a shield tube test are described below for a refrigerating machine fluid composition of a base oil and a refrigerant (HFC-245fa) of the type shown in Table 1. The performance was evaluated in the following manner. Table 1 shows the results. (1) Two-layer separation test 3 g of a sample oil / refrigerant (HFC-245fa) = 1/9 (weight ratio) was sealed in a pressure-resistant glass tube, and the temperature at which oil and refrigerant were separated was measured. (2) Shield tube test A catalyst Fe / Cu / Al was put in a glass tube, and a refrigerant (HFC)
-245fa) / oil of sample / water = 1g / 4g / 2,00
It was filled at a rate of 0 wtppm and sealed. 3 at 175 ° C
After holding for 0 days, the increase in oil appearance, catalyst appearance, and total acid value was determined.

[0067]

[Table 1]

[Note] ・ Type of base oil 1: polyoxypropylene glycol dimethyl ether kinematic viscosity 68 mm ² / s (40 ° C.), number average molecular weight 1,4
50 Total acid value 0.01 mgKOH / g 2: Polyoxypropylene (A) / polyoxyethylene (B) glycol monomethyl ether random copolymer, A unit / B unit (molar ratio) = 7/3 Kinematic viscosity 72 mm ² / s (40 ° C), number average molecular weight 1,5
00 Total acid value 0.01 mgKOH / g 3: Polyoxypropylene glycol mono n-butyl ether Kinematic viscosity 32 mm ² / s (40 ° C.), number average molecular weight 770 Total acid value 0.01 mgKOH / g 4: Polyoxypropylene (A) polyoxyethylene (B) glycol monobutyl n- butyl ether random copolymer, A unit / B unit (molar ratio) = 1/1 kinematic viscosity 120 mm ² / s (40 ° C.), the number-average molecular weight 2,
300 Total acid value 0.01 mg KOH / g 5: Polyvinyl ethyl ether, kinematic viscosity 120 mm ² /
s (40 ° C.), number average molecular weight 900, total acid value 0.01 m
gKOH / g

6: random copolymer of polyvinyl ethyl ether (A) and polyvinyl isobutyl ether (B),
A unit / B unit (molar ratio) = 8/2 Kinematic viscosity 74 mm ² / s (40 ° C.), number average molecular weight 730 Total acid value 0.01 mg KOH / g 7: Hindered ester (pentaerythritol and 2-
Ethylhexanoic acid, ester of 3,5,5-trimethylhexanoic acid) Kinematic viscosity 68 mm ² / s (40 ° C), total acid value 0.01 mg
KOH / g 8: Hindered ester (ester of pentaerythritol and caprylic acid, pelargonic acid), kinematic viscosity 113 mm
² / s (40 ° C.) Total acid value 0.01 mg KOH / g 9: Complex ester (trimethylolpropane and adipic acid ester), kinematic viscosity 130 mm ² / s
(40 ° C.), total acid value 0.01 mg KOH / g 10: paraffinic mineral oil, kinematic viscosity 68 mm ² / s (40
℃) Total acid value 0.01mgKOH / g

Examples 9 to 16, Comparative Examples 3 and 4, and Reference Example 1 A refrigerator comprising a refrigerating machine oil composition containing a base oil of the type shown in Table 2 and an additive and a refrigerant (HFC-245fa). For the fluid composition for use, a shield tube test and a seizure resistance test were performed in the following manner, and the performance was evaluated. Table 2 shows the results. (1) Shield tube test Same as above. (2) Seizure resistance test A seizure load (Lbs) was determined by using a FLEX test method based on ASTM D3233.

[0071]

[Table 2]

[Note]-Type of base oil Same as above. -Types of additives A: tricresyl phosphate (TCP) B: triphenyl phosphite C: 1-dodecene oxide D: 2-ethylhexyl glycidyl ether

[0073]

The fluid composition for a refrigerator of the present invention has excellent lubricating performance, is suitable for HFC-245fa refrigerant, and can be effectively used for a turbo refrigerator.

Claims (4)

[Claims] 1. A refrigerant containing (A) at least one fluorocarbon having 3 to 5 carbon atoms, and (B) at least one selected from (a) polyvinyl ether, (b) polyol ester, and (c) polyalkylene glycol. Kind of an oxygen-containing synthetic oil having a kinematic viscosity at 40 ° C. of 5 to 500 mm ² /
s, a base oil having a total acid value of 0.1 mgKOH / g or less, a fluid composition for a refrigerator. 2. The refrigerant of component (A) is HFC-245f
The fluid composition for a refrigerator according to claim 1, which is a. 3. The refrigerator according to claim 1, wherein the ratio of the refrigerant of the component (A) to the base oil of the component (B) is such that (A) / (B) (weight ratio) is 0.1 or more. Fluid composition. 4. The refrigerator according to claim 1, wherein the refrigerator is a turbo refrigerator.
4. The fluid composition for a refrigerator according to any one of 3.