JP3249858B2 - Refrigeration oil additive and refrigeration oil composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to refrigerating machine oil additives and compositions. More specifically, it relates to a refrigerating machine oil additive and a refrigerating machine oil composition having compatibility with a chlorofluorocarbon-based refrigerant containing no chlorine atom such as 1,1,1,2-tetrafluoroethane (hereinafter abbreviated as HFC-134a).

[0002]

2. Description of the Related Art Conventionally, dichlorodifluoromethane (CFC-12) has been widely used as a refrigerant for refrigerators such as electric refrigerators, room air conditioners, car air conditioners, and showcases. The refrigerating cycle of the refrigerator using this is composed of an evaporator, a compressor, a condenser, an expansion valve or a capillary tube, and a dryer. Usually, a compressor is a closed type, and a motor and a compression mechanism are integrated, and are immersed in a refrigerant and lubricating refrigerating machine oil in a compressor case. Therefore, so-called refrigerating machine oil is required to have lubricity, compatibility with a refrigerant, electrical insulation, chemical stability, especially thermal stability, stability against oxidation, stability against hydrolysis, and the like.

[0003] As is well known, CFC-12, which has been used as a refrigerant to date to protect the global environment, is subject to strict regulations. As an alternative, CFC-12 has similar properties (eg, vapor pressure) to CFC-12. HFC-134a is currently under consideration. However, in order to replace this, some problems must be solved. Among them, the biggest problem is to develop an oil that has good compatibility with CFC-12 alternative chlorofluorocarbons and can withstand long-term operation.
HFC-134a contains no chlorine atom in the molecule,
Since it has a large dipole moment, its compatibility with conventional refrigeration oils, such as low-polarity naphthenic mineral oils, paraffinic mineral oils, alkylbenzene-based synthetic oils, or poly-α-olefin-based synthetic oils, bad. As a result, phase separation between the refrigerant and the refrigerating machine oil occurs, and the moving parts in the circuit become poorly lubricated, causing problems such as seizure and abnormal vibration, thereby significantly reducing the life of the device and reducing the heat exchange efficiency. This leads to poor cooling.

[0004] On the other hand, in order to improve such problems, development of refrigerating machine oil having good compatibility with the refrigerant HFC-134a has been promoted. For example, Japanese Patent Application Laid-Open No. 4-19839
Ester-based oils described in JP-A Nos. 4-218592 and 4-220496;
2385, 3-205492, etc .; ether-containing lubricating oils described in JP-A-3-2055491, 4-202977; phosphorus-containing lubricating oils described in JP-A-4-202597; Kaihei 2-127498, 2
And silicon-containing lubricating oils described in US Pat. These oils commonly have polar functional groups such as esters, ethers and amides in the molecule, which contribute to the dissolution of CFC-12 alternative Freon. However, this type of oil has the disadvantages of having these functional groups. That is, these oils have low chemical stability, especially heat stability and stability against hydrolysis, and are not sufficiently durable as compared with the low-polarity oils described above. Accordingly, under actual conditions of use, the oil is decomposed and poor lubrication or sludge is generated, resulting in poor cooling. It cannot be said that a CFC-12 alternative refrigeration oil for CFC-12 has been developed which is still sufficiently satisfactory in use conditions requiring long-term stable operation.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an HF
An object of the present invention is to provide a refrigerating machine oil additive and a refrigerating machine oil composition containing the same, which overcome the above-mentioned drawbacks of the conventional refrigerating machine oil compatible with C-134a and enable long-term stable operation under actual use conditions. is there.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a refrigerating machine oil additive which is an acetal, ketal or ortho ester represented by the general formula (2).

[0007]

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Wherein R ¹ is hydrogen, an alkyl having 1 to 15 carbon atoms
A kill group or a fluoroalkyl group, R ² and R ³ are fluoro
An alkyl group or a fluoroalkyloxyalkyl group, R
⁴ is an alkyl group having 1 to 15 carbon atoms, a fluoroalkyl group,
Containing a fluoroalkyloxyalkyl group or a fluorine atom
It is an aryl group which may be substituted. X does not exist,
Alternatively, it is an oxygen atom. )

In the present invention, the compound represented by the general formula (1) may be an ester oil, an ether oil, a fluorine-containing lubricating oil,
The present invention relates to a refrigerating machine oil composition mixed with a base material comprising at least one synthetic oil selected from the group consisting of a phosphorus-containing lubricating oil and a silicon-containing lubricating oil.

The present inventors have conducted intensive studies in order to develop an alternative CFC refrigerating machine oil composition having sufficiently satisfactory reliability. As a result, the refrigerating machine oil composition was obtained without impairing the compatibility with the refrigerant and the electrical insulation. The present invention has been completed by finding a compound that suppresses the decomposition of the compound.

(1) wherein R ¹ , R ² , R ³ and R ⁴ have 1 carbon atom
Examples of the alkyl group of ~ 15 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group,
Heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group,
A linear or branched alkyl group such as a pentadecyl group,
Cyclic alkyl groups such as cyclohexyl group, methylcyclohexyl group and ethylcyclohexyl group.

Examples of the alkyloxyalkyl or aryloxyalkyl group include methoxyethyl, methoxyethoxyethyl, methoxyethoxyethoxyethyl, methoxypropyl, methoxypropoxypropyl, ethoxyethyl, propoxyethyl, Examples thereof include a linear or branched alkyloxyalkyl group such as a butoxyethyl group, a hexyloxyethyl group, an ethylhexyloxyethyl group, a phenoxyethyl group, and a phenoxypropyl group, or an aryloxyalkyl group.

Examples of the fluoroalkyl group include a trifluoroethyl group, a pentafluoropropyl group, a heptafluorobutyl group, a (perfluorobutyl) ethyl group, a (perfluorohexyl) ethyl group, and a (perfluorooctyl) ethyl group. A (perfluorodecyl) ethyl group, a (perfluoroethyl) hexyl group, a (perfluorobutyl) hexyl group, a (perfluorohexyl) hexyl group, a (perfluorooctyl) hexyl group, a (perfluoromethylbutyl) ethyl group, (Perfluoromethylhexyl) ethyl group, (perfluoromethyloctyl) ethyl group, (perfluoromethyldecyl) ethyl group, (perfluoromethylethyl) hexyl group, (perfluoromethylbutyl) hexyl group, (perfluoromethylhexyl) ) Hexyl , (Perfluoromethyl-octyl) hexyl group also, tetrafluoropropyl group,
1,1, ω-trihydroperfluoroalkyl groups such as octafluoropentyl group, dodecafluoroheptyl group, hexadecafluorononyl group, hexafluoroisopropyl group, bis (trifluoromethyl) propyl group, hexafluorobutyl group, etc. And these may be branched.

As the fluoroalkyloxyalkyl group, a group containing a hexafluoropropylene oxide oligomer as a skeleton, for example, 2-perfluoropropoxy-
2,3,3,3-tetrafluoropropyl group, C ₃ F ₇ [OCF
_{(CF 3) CF 2] n} O-CF (CF 3) CH 2 - (n = 0~3)
And the like.

The aryl group which may contain a fluorine atom includes phenyl, methylphenyl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl and the like. , Nonylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, propylnaphthyl, butylnaphthyl, pentylnaphthyl, perfluorophenyl, trifluoromethylphenyl, perfluoro (methylphenyl),
Perfluoronaphthyl groups and the like can be mentioned.

The acetal, ketal or orthoester represented by the general formula (1) can be obtained from commercial products or can be prepared according to a conventionally known method.
For example, The Chemical Society of Japan, New Experimental Chemistry, Vol. 14, No. 61
The corresponding aldehyde or ketone is acetalized or ketalized with the desired alcohol in the presence of an acid catalyst by the method described on pages 1 to 631, pages 1099 to 1103, or the corresponding halide and the alkali metal of the desired alcohol It can be obtained by reacting a salt or subjecting a corresponding acetal, ketal or orthoester to an exchange reaction with a desired alcohol in the presence of an acid catalyst. Further, in the orthoester, the corresponding nitrile can be reacted with a desired alcohol under hydrogen chloride to obtain a carboxylic acid imide ester hydrochloride once, followed by a reaction with the desired alcohol.

The refrigerating machine oil base material according to the present invention is not limited as long as it has a pour point of −20 ° C. or less and other low-temperature characteristics and heat stability applicable to the refrigerating machine oil. A base material comprising at least one synthetic oil selected from the group consisting of oil, fluorine-containing lubricating oil, phosphorus-containing lubricating oil and silicon-containing lubricating oil is preferred.

Examples of the ester oil include, for example, Petrotech, Vol. 8, No. 5, pp. 443-448 (1985) and Tribologist, Vol. 38, No. 1, pp. 28-31 (19).
93), JP-A-3-22797, JP-A-3-275799,
4-198394, 4-218592, 4-22
And monoesters, diesters, polyol esters, complex esters and hindered esters described in US Pat.

Examples of ether oils include, for example,
Vol. 29, No. 9, pp. 336-343 (1980), Petrotech, Vol. 8, No. 6, 562-566 (1985) and Tribologist, Vol. 37, No. 12, No. 1003 ~ 1006 pages (199
Polyalkylene glycol as shown in 2),
That is, monohydric alcohol, ethylene glycol, propylene glycol, neopentyl glycol, glycerin,
Examples thereof include those obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide or a mixture thereof to a polyhydric alcohol such as pentaerythritol. Further, polyalkylene glycols such as a dialkyl ether type or a diester type in which the hydroxyl group at the terminal thereof has been modified may be mentioned.

As a fluorine-containing lubricating oil, see Lubrication Journal, Vol. 32,
No. 2, pp. 109-110 (1987), perfluoropolyether oils and perfluorocarbon oils, and aromatic group-containing perfluoropolyethers described in JP-A-3-205549 and JP-A-4-202397. No.

As the phosphorus-containing lubricating oil, JP-A-4-202
597, substituted phosphonitrile esters such as alkoxy, alkyloxyalkoxy, fluoroalkoxy or fluoroalkoxy having an ether structure as described in Japanese Patent Application No. 3-262895, Journal of Lubrication, Vol.
No. 2, pages 103 to 106 (1987).

As the silicon-containing lubricating oil, JP-A No. 2-12
7498, such as silicone, silicate ester, and tetraalkyl silicon.

By adding the compound of the present invention, the stability of the oil exemplified above can be remarkably improved. The compound of the present invention is desirably added so that the concentration in one or more of the above-mentioned synthetic oils is 0.1 to 50% by weight.

In order to further improve the performance of the refrigerating machine oil composition of the present invention, various known refrigerating machine oil additives such as a load-bearing additive, an antioxidant, and a metal deactivator may be used, if necessary. An agent, an antifoaming agent, a detergent / dispersant, a viscosity index improver, an oil agent, an antiwear agent, an extreme pressure agent, a rust inhibitor, a corrosion inhibitor, a pour point depressant and the like can be appropriately added.

[0025]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. still,
In the following Examples and Comparative Examples, the following samples were used as lubricating oils.

Sample 1 A diester of 3-methyl-1,5-pentanediol represented by the following formula (2) and 3,5,5-trimethylhexanoic acid. _{(H 3 C) 3 CCH 2} CH (CH 3) CH 2 COOC 2 H 4 -CH (CH 3) C 2 H 4 OCOCH 2 CH (CH 3) CH 2 C (CH 3) 3 (2)

Sample 2 As a neopentyl type polyol ester oil obtained from a dihydric alcohol, a dihydric carboxylic acid and a monohydric carboxylic acid, 1.0 mol of neopentyl glycol, 0.5 mol of adipic acid
An ester oil obtained by reacting 1.0 mol of caproic acid with 1.0 mol of caproic acid.

Sample 3 An ester oil obtained by reacting 1.0 mol of pentaerythritol, 2.0 mol of caproic acid and 2.0 mol of 2-methylbutanoic acid as a neopentyl type polyol ester oil obtained from a polyhydric alcohol and a monohydric carboxylic acid.

Sample 4 A polyalkylene glycol oil represented by the following formula (3). _{C 4 H 9 O [CH 2} CH (CH 3) O] n H -average molecular weight: 650 (3)

Sample 5 A polyalkylene glycol oil represented by the following formula (4). _{C 4 H 9 O [CH 2} CH (CH 3) O] n CH 3 Average molecular weight: 1000 (4)

Sample 6 A polyalkylene glycol oil represented by the following formula (5).

[0032]

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Sample 7 A fluorine-containing polyether oil represented by the following formula (6):

[0034]

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Sample 8 A cyclic phosphonitrile ester oil represented by the following formula (7). _{[C 4 H 9 O (C} 2 H 4 O) 2 (C 3 H 6 O) 4] 6 N 3 P 3 (7)

Sample 9 A cyclic phosphonitrile ester oil represented by the following formula (8). (HCF ₂ CF ₂ CF ₂ CF ₂ CH ₂ O) ₁ (CF ₃ CF ₂ CH ₂ O) _m N ₃ P ₃ (8) (where l + m = 6, 1 ≒ 3)

Sample 10 A silicone oil represented by the following formula (9).

[0038]

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Sample 11 A mixed oil of 35 parts by weight of Sample 3 and 65 parts by weight of Sample 9.

Example 1 60 g of chloroform, 30 g of 1,1,5-trihydrooctafluoropentanol and 5 g of ferric chloride were added to a reactor equipped with a cooling tube, and reacted under reflux for 24 hours. After the reaction solution was concentrated, 27 g of orthoformate represented by the following formula (10) was obtained by distillation under reduced pressure. Yield: 89%, boiling point: 117-11
8 ° C / 0.6 torr. FIG. 1 shows ¹ H-NMR (solvent: deuterated chloroform) of this product.

[0041]

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Example 2 A mixed solution of 10 g of acetonitrile and 13 g of ethanol was added at 10 ° C.
After 10 g of hydrogen chloride gas was introduced below, the mixture was stirred at room temperature for 15 hours. Next, 127 g of 1,1,5-trihydrooctafluoropentanol was added and reacted at 45 ° C. for 24 hours. After neutralizing the reaction solution by introducing ammonia gas, the orthoacetate ester represented by the following formula (11) is distilled off under reduced pressure.
12 g were obtained. Yield: 86%, boiling point: 110-112 ° C / 0.7 torr.
Its ¹ H-NMR (solvent: deuterated chloroform) is shown in FIG.

[0043]

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Example 3 A catalytic amount of concentrated sulfuric acid was added to a mixture of 10 g of triethyl orthoacetate and 100 g of perfluorobutylethanol, and the mixture was stirred at 100 ° C. while removing the produced ethanol. The reaction was performed until no more ethanol was produced. The reaction solution was concentrated and distilled under reduced pressure to obtain 43 g of orthoacetic acid ester represented by the following formula (12). Yield: 85%, boiling point: 115-116 ° C
/0.6torr. FIG. 3 shows the ¹ H-NMR (solvent: deuterated chloroform) of this product.

[0045]

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Example 4 5.8 g of acetone and 13 of perfluorobutylethanol
2 g was dissolved in 100 ml of benzene, a catalytic amount of concentrated sulfuric acid was added, and the mixture was stirred at 100 ° C. for 5 hours. The reaction solution was concentrated, and 43 g of a ketal represented by the following formula (13) was obtained by distillation under reduced pressure. Yield: 75%, boiling point: 110-112 ° C / 0.8 torr. As a result of ¹ H-NMR analysis of this compound, the methylene group hydrogens based ketal structure _{(C-OC H 2 CH 2} CF 2 CF 2 CF
₂ CF ₃ ) peak was confirmed at 4.0 to 4.2 ppm.

[0047]

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Example 5 10 g of benzaldehyde, 40 g of 1,1,3-trihydrotetrafluoropropanol, and a catalytic amount of p-toluenesulfonic acid were dissolved in 100 ml of benzene, and the mixture was heated and stirred at 100 ° C. while removing generated water. . The reaction was run until no more water was formed. Next, the reaction solution was neutralized with sodium hydrogen carbonate, and then 30 g of an acetal represented by the following formula (14) was obtained by distillation under reduced pressure. Yield: 87%, boiling point: 116-119 ° C / 0.
3torr. As a result of measuring ¹ H-NMR of this product, it was found that hydrogen of a methylene group based on an acetal structure (C-OC H ₂ CF ₂
CF ₂ H) peak was confirmed at 4.0 to 4.2 ppm.

[0049]

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Examples 6 to 12 Table 1 shows the reaction conditions and analysis results of the additives synthesized in the same manner as in Examples 1 to 5. Note that the results of ¹ H-NMR in Table 1 indicate that the methylene group (C-C) of the fluoroalkoxy group substituted on the oxygen of the acetal, ketal or orthoester was
It showed a chemical shift of OC H ₂ ~Rf).

[0051]

[Table 1]

Embodiment 1329And Comparative Examples 1 to38  20 parts by weight of each sample oil with water content adjusted to 1000 ppm
80 parts by weight of HFC-134a and the types shown in Tables 2-4
And the amount of each additive, add 100 ml stainless steel (SUS-3
16) Put into an autoclave made of steel, copper and aluminum.
Add one piece of Luminium metal piece (50 × 25 × 1.5mm)
After sealing, the mixture was heated at 175 ° C. for 14 days (336 hours). heating
After the test, vacuum degassing is performed to remove HFC-134a and water.
The refrigeration oil composition after the test, the kinematic viscosity,
The acid value was measured. The kinematic viscosity was JIS K2501, all
The acid value was measured according to JIS K2283. Metal piece below
After the test, use the materials shown in
And the change in weight was measured.

Metal piece material: Steel JIS G3141 Copper JIS H3100 Aluminum JIS H4000 The results are summarized in Tables 2 to 5. In addition, HFC-134a
As for the solubility, those which were uniformly dissolved at a temperature of −20 to 60 ° C. were evaluated as ○. The presence or absence of sludge was visually determined.

[0054]

[Table 2]

[0055]

[Table 3]

[0056]

[Table 4]

[0057]

[Table 5]

Example30-38And comparative examples39-62  In accordance with JIS C2101, the volume resistivity of the test oil is 25
Measured in ° C. Also, according to ASTM D-3233
The maximum load (lbs) of the burn-in
The measurement was performed in an atmosphere 4a. The results are shown in Tables 6 and 7.
You.

[0059]

[Table 6]

[0060]

[Table 7]

[0061]

EFFECT OF THE INVENTION By adding the compound of the present invention, decomposition, which is a drawback of the conventional chlorine-free refrigerant oil for HFC-134a such as HFC-134a, is suppressed, and the durability thereof is greatly improved. It has become possible to improve. in addition,
An additive containing a fluorine atom in the molecule also has an effect of imparting lubricity to a refrigerator oil base material. From these results, according to the present invention, the generation of sludge, which is a major problem when using HFC-134a in a hermetic compressor, is suppressed,
A refrigerating machine oil can be provided which does not impair the electrical insulation and has greatly improved equipment life and refrigerating efficiency.

[Brief description of the drawings]

FIG. 1 shows ¹ H of orthoformate obtained in Example 1.
-It is an NMR spectrum.

FIG. 2 shows ¹ H of orthoacetate obtained in Example 2.
-It is an NMR spectrum.

FIG. 3 shows ¹ H of orthoacetic acid ester obtained in Example 3.
-It is an NMR spectrum.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI C10M 105: 76 C10M 105: 76 105: 74) 105: 74) C10N 30:02 C10N 30:02 30:08 30:08 40: 16 40:16 40:30 40:30 (58) Field surveyed (Int. Cl. ⁷ , DB name) C10M 169/04

Claims (3)

(57) [Claims] 1. A refrigerating machine oil additive which is an acetal, ketal or orthoester represented by the general formula 1. Embedded image ( Wherein R ¹ is hydrogen, an alkyl group having 1 to 15 carbon atoms or
A fluoroalkyl group, R ² and R ³ are a fluoroalkyl group or
Is a fluoroalkyloxyalkyl group, and R ⁴ is carbon atom 1
~ 15 alkyl groups, fluoroalkyl groups, fluoroal
May contain a killoxyalkyl group or a fluorine atom
Aryl group. X is absent or an oxygen atom. ) 2. A compound represented by the general formula (1):
A refrigerating machine oil composition blended in a base material comprising at least one synthetic oil selected from the group consisting of ester oils, ether oils, fluorine-containing lubricating oils, phosphorus-containing lubricating oils and silicon-containing lubricating oils. 3. The method according to claim 1, wherein the compound represented by the general formula (1) is 0.1%.
3. The refrigerating machine oil composition according to claim 2, wherein the composition is 1 to 50% by weight.