JPH09235577A - Lubricant composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lubricant composition containing a cyclic ketal or acetal compound having a specific structure and a polyalkylene glycol compound and excellent in compatibility with hydrofluorocarbons and further excellent in electric insulation, hygroscopicity, etc. SOLUTION: This lubricant composition contains (A) a polyalkylene glycol compound having a dynamic viscosity of 0.1-100mm<2> /S at 100 deg.C and (B) a cyclic ketal or acetal. The component B is obtained from one or more kinds of tetrahydric, hexahydric, octahydric and decahydric alcohols and one or more kinds of a carbonyl compound of the formula (R<1> is H, a 1-18C linear, branched or cyclic alkyl; R<2> is a 1-18C linear, branched or cyclic alkyl; or R<1> and R<2> may be combined with each other to form a 2-36C alkylene) and its reactive derivatives: ketals and acetals.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lubricating oil composition containing a polyalkylene glycol compound having a kinematic viscosity at 100 ° C. of 0.1 to 100 mm ² / s and a cyclic ketal or cyclic acetal having a specific structure. Furthermore, it relates to a composition for a working fluid of a refrigerator using the lubricating oil composition.

[0002]

2. Description of the Related Art In recent years, the performance required for lubricating oils has become more severe with the demand for longer refueling period, energy saving, and higher performance and smaller machinery. Lubricating oils having excellent stability and oxidation stability have been strongly demanded. In addition, global warming of the ozone layer due to CFCs, global warming due to carbon dioxide and methane, acid rain and forest destruction due to sulfur dioxide and NOx in exhaust gas, soil and lake pollution due to chemical leakage, etc. The problem is being highlighted, and lubricants are also required to deal with it.

In order to meet the demand for improvement in thermal stability and oxidation stability, ethers such as polyalkylene glycols and esters such as aliphatic diesters and hindered esters have been developed, and engine oil, hydraulic oil, grease base oil, gear Used for oil, rolling oil, precision machine oil, etc.

However, ethers such as polyalkylene glycols have the drawbacks of high hygroscopicity and insolubility of conventionally used additives, because they have too high a polarity as compared with conventionally used mineral oils. ing. As an ether whose polarity is not so high as compared with this polyalkylene glycol, there is one synthesized from an alkyl halide and a polyol described in Japanese Patent Publication No. 1-29240, but a slight amount of halogen remains in the produced ether. , The thermal stability and the oxidative stability may be deteriorated.

Further, the ester also has a problem that it produces a carboxylic acid by hydrolysis and corrodes a metal, and has an advantage of lowering a friction coefficient due to its excellent adsorptivity to a metal. It has the drawback of inhibiting the effects of extreme pressure agents.

[0006] Therefore, there is a demand for a synthetic lubricating oil which is not so high in polarity, is excellent in thermal stability and oxidative stability, does not generate carboxylic acid due to hydrolysis, etc., and has low hygroscopicity.

On the other hand, the use of dichlorodifluoromethane (CFC12), which is used in refrigerators and car coolers for the protection of the ozone layer, is restricted from the viewpoint of the global environment.
It was decided that the use would be banned by the end of five years. Further, subsequently, the use of chlorodifluoromethane (HCFC22) used for room air conditioners and the like is about to be regulated. Therefore, as an alternative to CFC12 and HCFC22, hydrofluorocarbons that do not destroy the ozone layer, such as 1,1,1,2-tetrafluoroethane (H
FC134a), difluoromethane (HFC32) and pentafluoroethane (HFC125) have been developed.

However, hydrofluorocarbon is CF
Since the polarity is higher than that of C12 or HCFC22, when a lubricating oil such as naphthene-based mineral oil, poly α-olefin, or alkylbenzene which has been generally used as a refrigerating machine oil is used, the phase of these lubricating oil and hydrofluorocarbon is Poor solubility, causing two-phase separation at low temperature.
When two-phase separation occurs, the oil return deteriorates and a thick oil film adheres to the vicinity of the condenser or evaporator as a heat exchanger to hinder heat transfer, and also causes serious defects such as poor lubrication and foaming at startup. Cause of. Therefore, the conventional refrigerating machine oil cannot be used as a refrigerating machine oil under these new refrigerant atmospheres. Therefore, there is a need for a lubricating oil that has good compatibility with hydrofluorocarbons.

Also, regarding the lubricity, CFC12 and HC
In FC22, there was an effect that it partially decomposed to generate hydrogen chloride, and this hydrogen chloride reacted with the friction surface to form a chloride film and improve the lubricity. However, since such effects cannot be expected for hydrofluorocarbons that do not contain chlorine atoms, refrigerating machine oils used with hydrofluorocarbons are required to have lubricating oils with even better lubricity than conventional ones.

Further, the refrigerating machine oil used together with hydrofluorocarbon must have good thermal stability in the presence of hydrofluorocarbon.

In addition to this, in compression type refrigerators such as electric refrigerators and room air conditioners, there are organic materials used for motors such as insulating materials and enameled wires, so that a working fluid consisting of hydrofluorocarbon and refrigerator oil is used. It is necessary that they do not adversely affect these organic materials and that they also have good electrical insulation.
Further, heat of refrigerating machine oil, deterioration products due to air or hydrolysis, and remaining in the refrigerating cycle of the refrigerating machine, various oil agents such as mineral oil-based and hydrocarbon synthetic oil-based used in the manufacture and assembly of the refrigerator, For example, drawing oil, cutting oil, rust preventive oil, press oil, cleaning oil, etc. cause a decrease in the flow rate of the capillaries, causing a decrease in refrigeration efficiency. Therefore, the refrigerating machine oil used together with the hydrofluorocarbon needs to have a high ability to dissolve contaminants such as these deteriorated products and residual oil agents.

Hydrofluorocarbons such as 1,1,1,
As a refrigerating machine oil that can be used with 2-tetrafluoroethane (HFC134a), US Pat. No. 4,755,316
(Japanese Patent Publication No. 2-502385) and Japanese Unexamined Patent Publication No.
-14894 (European Patent No. 377,122),
JP-A-2-182780 (WO90 / 05172)
No.) and the like, polyalkylene glycol compounds are disclosed.

Since the polyalkylene glycol-based compound has a higher polarity than the naphthene-based mineral oil, the compatibility with HFC134a at low temperature is certainly good. However,
As described in U.S. Pat. No. 4,755,316, polyalkylene glycol-based compounds, on the contrary, have a problem that two-phase separation occurs when the temperature rises. Further, the polyalkylene glycol compound has some other problems. One is that it has poor electrical insulation. This is a very big problem and cannot be used in refrigerators for electric refrigerators and refrigerators for air conditioners in which the motor is built in the compressor. These compounds have been suggested for use in such car-free air conditioning applications. Another problem is that it is highly hygroscopic. Due to the water content in the polyalkylene glycol compound, the PET film or the like, which is an organic material, is hydrolyzed. By reducing the number of ether bonds per unit weight, electrical insulation can be improved and hygroscopicity can be reduced, but compatibility with hydrofluorocarbon becomes poor. Thus, an ether compound such as polyalkylene glycol cannot achieve both compatibility with hydrofluorocarbon, electrical insulation and hygroscopicity.

Ester-based compounds and carbonate-based compounds have been developed in order to improve the problems of polyalkylene glycol-based compounds such as electric insulation and hygroscopicity. For example, 1,1,1,2-tetrafluoroethane (HFC13
As a refrigerating machine oil that can be used together with 4a), a mixed oil of a polyalkylene glycol compound and an ester oil is disclosed in US Pat. No. 4,851,144 (JP-A-2-276894) and JP-A-2-158693.
Japanese Patent Publication No. 3-505602 (WO90 / 12849)
), JP-A-3-128991, JP-A-3-12
Ester oils are disclosed in JP-A-8992, JP-A-3-88892 and JP-A-3-179091. JP-A-2-132178, JP-A-3-149
295 and European Patent 421,298 disclose carbonate oils.

Ester-based compounds and carbonate-based compounds have excellent compatibility with hydrofluorocarbons and also have excellent thermal stability in the presence of hydrofluorocarbons. Compared with polyalkylene glycol-based compounds, it has extremely excellent electric insulation and also has considerably low hygroscopicity.
However, compared with CFC12-mineral oil system, which is a conventional working fluid, both hydrofluorocarbon-ester oil system and hydrofluorocarbon-carbonate oil system have higher polarities of both freon and oil, and are likely to contain water.
Therefore, there is a problem that the ester hydrolyzes to generate a carboxylic acid, and the generated carboxylic acid corrodes a metal to cause abrasion. In addition, the carbonate oil causes hydrolysis, produces non-condensable carbon dioxide, and causes a problem that the refrigerating capacity is lowered.

Particularly in a room air conditioner, the refrigerant is exclusively filled in the field, so it is almost impossible to prevent the mixture of water unlike the case of a refrigerator which is filled in a factory. -Carbonate oil system is concerned about the reliability of room air conditioners. Further, such an ester compound or a carbonate compound has an insufficient ability to dissolve contaminants, which may cause a reduction in the flow rate of the capillary or a reduction in the refrigeration efficiency due to clogging or the like.

Further, as a polyether compound having improved electrical insulation of polyalkylene glycol, WO93 /
Japanese Patent No. 24435 discloses a polyvinyl ether compound. This polyvinyl ether-based compound is obtained by polymerizing a vinyl ether-based monomer and hydrogenating it, and it is disclosed that this compound has good compatibility with hydrofluorocarbon and also has good electrical insulation. . However, since polyvinyl ether compounds are synthesized by the polymerization method and the products have different molecular weights, some high molecular weight compounds may cause clogging of the capillary tube, and compatibility with hydrofluorocarbons. May worsen. In addition, it is difficult to say that the post-treatment method is complicated and the unstable vinyl ether-based monomer is used as a raw material, and that the yield is not necessarily high. In particular, those having a low degree of polymerization (polymerization degree of around 6) have a drawback that the yield is low. In addition, vinyl ether-based monomers are difficult to obtain depending on the structure,
It is expensive. Further, such a polyether compound has an insufficient ability to dissolve contaminants, which may cause a decrease in the freezing efficiency due to a decrease in the flow rate of the capillary, clogging, or the like.

On the other hand, examples in which a cyclic ketal or a cyclic acetal is used as a working fluid of a refrigerator are described in JP-A-4-320498 and JP-A-6-57243.
The former is a ketal or acetal obtained from a monohydric alcohol or a dihydric alcohol and a ketone or an aldehyde, and it is stated that the ketal or acetal is blended with an ester or polyalkylene glycol-based synthetic lubricating oil, and the latter is an intramolecular compound. It is a derivative of ester or carbonate of glycerin, trimethylolethane, trimethylolpropane, pentaerythritol containing a ketal or acetal group. The former acetals and ketals have the drawbacks of low molecular weight, low boiling point and flash point, and also low viscosity. Therefore,
When mixed with an ester or an ether such as polyalkylene glycol, there is a drawback that the viscosity and the flash point are remarkably lowered. Further, the latter acetal and ketal have a drawback that they are expensive because they undergo two or more reaction steps in the production, and some have a drawback that they are difficult to obtain with high purity. Further, the latter acetals and ketals specifically disclosed include the problem that two or more ether bonds are contained in the molecule and the improvement of electrical insulation is not sufficient. Also,
Such a cyclic ketal or cyclic acetal compound has an insufficient ability to dissolve contaminants, which may cause a decrease in the flow rate of the capillary or a decrease in the refrigeration efficiency due to clogging. On the other hand, Japanese Patent Application Laid-Open No. 8-73880 describes addition of an oxazoline compound in order to prevent metal corrosion caused by contaminants and the influence of sludge. However, the thermal stability of the oxazoline compound itself is poor, which may deteriorate the refrigerating machine oil and cause clogging of the capillaries.

[0019]

As described above, the hydrofluorocarbon-polyalkylene glycol type that has been developed so far has hygroscopicity and electrical insulation, and the hydrofluorocarbon-ester type and the hydrofluorocarbon-carbonate type have hydrolysis resistance. In addition, any of these systems are more likely to contain water than conventional CFC12-mineral oil systems, causing a decrease in thermal stability, deterioration of organic materials, corrosion of metals, abrasion, etc. I'm not satisfied. Further, since the polyvinyl ether compound has a high molecular weight compound in part because it has a molecular weight distribution, it has a drawback that the compatibility is lowered, and there is a drawback that the raw material species are limited and the cost becomes high. In addition, the ketals and acetals that have been reported so far have the drawbacks of low molecular weight and high price. Further, the lubricating oil composition and the refrigerator working fluid composition that have been developed so far have insufficient contamination dissolving power, which may cause a reduction in the refrigeration efficiency due to a decrease in the flow rate of the capillary or clogging.

Therefore, the object of the present invention is to provide excellent thermal stability and oxidative stability, no generation of carboxylic acid due to hydrolysis, low hygroscopicity, high viscosity index, low cost, and good solubility for contamination. To provide a high lubricating oil composition,
In addition, the composition for refrigerator working fluid is excellent in compatibility with hydrofluorocarbons, electric insulation, hygroscopicity, viscosity index, etc., does not generate carboxylic acid due to hydrolysis, etc., is inexpensive, and has high contamination dissolving power. To provide things.

[0021]

As a result of intensive studies to solve the above problems, the present inventors have found that a composition containing a cyclic ketal or cyclic acetal compound having a specific structure and a polyalkylene glycol compound. However, it has excellent compatibility with hydrofluorocarbons, excellent electrical insulation, excellent lubricity and heat resistance, excellent hygroscopicity, excellent viscosity index, and does not generate carboxylic acid due to hydrolysis, It was discovered that an extremely excellent lubricating oil composition having a high ability to dissolve contaminants could be obtained, and further research was conducted to complete the present invention.

That is, the gist of the present invention is [1] 100
A lubricating oil composition comprising a polyalkylene glycol compound having a kinematic viscosity of 0.1 to 100 mm ² / s at 0 ° C. and a cyclic ketal or a cyclic acetal, [2] the cyclic ketal or the cyclic acetal is 4 One or more polyhydric alcohols having an even valence of 10 to 10 and a general formula (1)

[0023]

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(In the formula, R ¹ is a hydrogen atom or a carbon number of 1 to
18 represents a linear, branched, or cyclic alkyl group, and R ² represents a linear, branched, or cyclic alkyl group having 1 to 18 carbon atoms. Alternatively, R ¹ and R ² together represent an alkylene group having 2 to 36 carbon atoms. [4] The lubricating oil composition according to the above [1], which is obtained from at least one kind of a ketal or acetal which is a carbonyl compound represented by the above) or a reactive derivative thereof, [3] a cyclic ketal or a cyclic acetal is 4 One or more polyhydric alcohols having an even or higher valence of 8 or more and a general formula (2)

[0025]

[Chemical 6]

(In the formula, R ³ is a hydrogen atom or a carbon number of 1 to
12 represents a straight chain, branched chain or cyclic alkyl group, and R ⁴ represents a straight chain, branched chain or cyclic alkyl group having 1 to 12 carbon atoms. Alternatively, R ³ and R ⁴ together represent an alkylene group having 2 to 13 carbon atoms. R ³ and R
The total carbon number of ⁴ is 1 to 13. [4] The lubricating oil composition according to the above [1], which is obtained from one or more of a carbonyl compound represented by the formula (1) or a reactive derivative thereof, a ketal or an acetal, and [4] the polyhydric alcohol has an ether bond. The lubricating oil composition according to the above [2] or [3], wherein the cyclic ketal or cyclic acetal has a 1,3-dioxolane structure and / or 1 The lubricating oil composition according to any one of [1] to [4] above, which comprises a 1,3-dioxane structure, [6] wherein the cyclic ketal or cyclic acetal has a tetravalent or hexavalent carbon number of 4 to 2.
[4] or [5] above, which is obtained from a saturated aliphatic alcohol of 0 and one or more of a carbonyl compound represented by the general formula (2) or a reactive derivative thereof, a ketal or an acetal. Lubricating oil composition, [7]
The cyclic ketal or cyclic acetal is represented by the general formula (3) or (4)

[0027]

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(In the formula, R ³ represents a hydrogen atom or a carbon number of 1 to 1.
12 represents a straight chain, branched chain or cyclic alkyl group, and R ⁴ represents a straight chain, branched chain or cyclic alkyl group having 1 to 12 carbon atoms. Alternatively, R ³ and R ⁴ together represent an alkylene group having 2 to 13 carbon atoms. R ³ and R
The total carbon number of ⁴ is 1 to 13. ] The lubricating oil composition according to the above [1], which is represented by the above [8], wherein the cyclic ketal or cyclic acetal is represented by the general formula (5) or (6)

[0029]

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(In the formula, R ³ is a hydrogen atom or a carbon number of 1 to
12 represents a straight chain, branched chain or cyclic alkyl group, and R ⁴ represents a straight chain, branched chain or cyclic alkyl group having 1 to 12 carbon atoms. Alternatively, R ³ and R ⁴ together represent an alkylene group having 2 to 13 carbon atoms. R ³ and R
The total carbon number of ⁴ is 1 to 13. ] The lubricating oil composition according to the above [1], which is represented by

[9] The mixing ratio of the polyalkylene glycol compound and the cyclic ketal or the cyclic acetal in the lubricating oil composition is polyalkylene glycol compound / cyclic ketal, cyclic acetal =
[1] to 1/99 to 99/1 (weight ratio)
[8] The lubricating oil composition according to any one of [1] to [10], wherein the polyalkylene glycol compound is a compound represented by the following general formula (7).

[9] the lubricating oil composition according to any ^{one, A- (O- (R 5 O} ) v-R 6) w (7) ( wherein, R ⁵ represents a linear or branched chain alkylene of 2 to 4 carbon atoms represents a group .R ⁶ is a hydrogen atom, a hydrocarbon group having 1 to 18 carbon atoms, or represents .A hydrogen atom acyl group having 2 to 18 carbon atoms, w-valent alcohol residue having 1 to 18 carbon atoms, Alternatively, it represents a w-valent phenol residue having 6 to 18 carbon atoms, and v is 1 to
The number of 50 and w represent the number of 1 to 6. However, v R ⁵
O, w R ⁶ and w O— (R ⁵ O) v—R ⁶ may be the same or different. ] [11] The polyalkylene glycol compound is a compound represented by the following general formula (8) [1] to

[9] the lubricating oil composition according to any one ^{of, R 7 O- (R 5 O} ) x-R 8 (8) ( wherein, R ⁵ represents a linear or branched chain alkylene group having 2 to 4 carbon atoms R ⁷ represents a hydrocarbon group having 1 to 18 carbon atoms, R ⁸ represents a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and x represents a number of 1 to 50, provided that R ⁷ and R ⁸ may be the same or different, and x R ⁵
O may be the same or different. ] [12] A refrigerating machine oil containing the lubricating oil composition according to any one of [1] to [11] and a composition for a working fluid of a refrigerating machine containing hydrofluorocarbon, [13] hydrofluorocarbon and refrigerating machine oil Fluorocarbon / refrigerating machine oil = 50/1 to 1/20 (weight ratio) The composition for a refrigerating machine working fluid according to [12] above.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION 1. Regarding the cyclic ketal and cyclic acetal, the polyhydric alcohol relating to the cyclic ketal or the cyclic acetal used in the present invention is a polyhydric alcohol having an even valence of 4 to 10 and is preferably tetravalent, hexavalent or octavalent. And more preferably tetravalent or hexavalent. In the present specification, the polyhydric alcohol relating to the cyclic ketal or the cyclic acetal refers to the polyhydric alcohol when the cyclic ketal or the cyclic acetal is formed from the polyhydric alcohol and a carbonyl compound or the like. If it has a valence of more than 10, the viscosity of the obtained cyclic ketal or cyclic acetal becomes too high, and the viscosity of the obtained lubricating oil composition becomes too high. If it is less than tetravalent, the molecular weight will be too low, and the boiling point and flash point of the resulting lubricating oil composition will be too low, which is not preferable. If the valence of the polyhydric alcohol is odd, unreacted hydroxyl groups will always remain and the viscosity will increase, which is not preferable. When used as a refrigerator working fluid,
If the hydroxyl group remains, the compatibility with the hydrofluorocarbon deteriorates, which is not preferable. By making the unreacted hydroxyl group into an ether structure by an alkylation reaction, the viscosity and compatibility with hydrofluorocarbon can be improved, but this is not preferable because the number of reaction steps in production increases.
In addition, this makes it difficult to obtain a highly pure product.

Specifically, erythritol, diglycerin, arabinose, ribose, sorbitol, mannitol, galactitol, iditol, talitol, allitol, 4,7-dioxadecane-1,2,9,10-tetraol, 5-methyl -4,7-Dioxadecane-1,2,9,10-tetraol, 4,7,10- Trioxatridecane-1,2,12,13-tetraol, 1,6-dimethoxyhexane-2,3 Polyhydric alcohols such as 1,4,5-tetraol and 3,4-diethoxyhexane-1,2,5,6-tetraol, pentaerythritol, ditrimethylolethane, ditrimethylolpropane, dipentaerythritol, tripenta Erythritol, 2,9-diethyl-2,9-dihydroxymethyl-4,7-dioxadecane
-1,10-diol, 2,12-diethyl-2,12-dihydroxymethyl-5,8-dimethyl-4,7,10-trioxatridecane-1,13
-A hindered alcohol such as a diol.

Of these, 4,7-dioxadecane-1,2,9,10-
Tetraol, 5-methyl-4,7-dioxadecane-1,2,9,1
0-tetraol, 4,7,10-trioxatridecane-1,2,1
2,13-Tetraol, 1,6-dimethoxyhexane-2,3,4,5
-Tetraol, 3,4-diethoxyhexane-1,2,5,6-tetraol, 2,9-diethyl-2,9-dihydroxymethyl-
4,7-Dioxadecane-1,10-diol, 2,12-diethyl-
Polyhydric alcohols with two or more ether bonds, such as 2,12-dihydroxymethyl-5,8-dimethyl-4,7,10-trioxatridecane-1,13-diol, are easy to obtain industrially. Rather, it requires several steps to manufacture, which is expensive and is not preferable.

The polyhydric alcohol relating to the cyclic ketal or cyclic acetal used in the present invention has 4 to 2 carbon atoms.
5 and preferably 4 to 20. If the carbon number exceeds 25, the viscosity of the obtained cyclic ketal or cyclic acetal becomes too high, and the viscosity of the obtained lubricating oil composition becomes too high. If the carbon number is less than 4, the molecular weight becomes too low, and the resulting lubricating oil composition has low boiling point and flash point, which is not preferable.

The polyhydric alcohol relating to the cyclic ketal or cyclic acetal used in the present invention is a saturated aliphatic alcohol. An unsaturated bond is not preferable because the resulting lubricating oil composition has poor thermal stability.

The polyhydric alcohol relating to the cyclic ketal or cyclic acetal used in the present invention is most preferably one having no ether bond in the molecule from the viewpoint of having a good electric insulating property. Moreover, even if it has an ether bond, one is preferable. If two or more are present, the electrical insulation will be poor, so it is not preferable when the lubricating oil composition of the present invention is used as an electrical insulating oil, a working fluid for a refrigerator, or the like.
Specific examples of the polyhydric alcohol having no ether bond in the molecule include erythritol, sorbitol, mannitol, galactitol, iditol, talitol, allitol, pentaerythritol, etc., and specific examples of the polyhydric alcohol having one ether bond. Examples include diglycerin, ditrimethylolpropane, ditrimethylolethane and the like.

When the lubricating oil composition of the present invention is used as a working fluid for a refrigerator, the valency of the polyhydric alcohol related to the cyclic ketal or cyclic acetal is preferably 4, 6, or 8. It is preferably tetravalent or hexavalent. If the valence of the polyhydric alcohol related to the cyclic ketal or cyclic acetal is higher than 8, the viscosity will be too high for a refrigerating machine oil, the viscosity of the resulting lubricating oil composition will be too high, and the compatibility with hydrofluorocarbons will be high. Is not preferable because it becomes worse. Further, if the valence of the polyhydric alcohol relating to the cyclic ketal or the cyclic acetal is less than tetravalent, the molecular weight becomes too low, and the boiling point and the flash point of the obtained lubricating oil composition become low, which is not preferable.

The polyhydric alcohol having a cyclic ketal or cyclic acetal preferably has 4 to 20 carbon atoms, more preferably 4 to 15 carbon atoms, and particularly preferably 4 to 1 carbon atoms.
0. If the polyhydric alcohol related to the cyclic ketal or cyclic acetal has more than 20 carbon atoms, the resulting lubricating oil composition has poor compatibility with hydrofluorocarbons, which is not preferable. If the number of carbon atoms of the polyhydric alcohol relating to the cyclic ketal or cyclic acetal is less than 4, the molecular weight becomes too low, and the boiling point and flash point of the resulting lubricating oil composition become low, which is not preferable. Further, when an alcohol having a high symmetry such as pentaerythritol is used, the melting point of the obtained cyclic ketal or cyclic acetal becomes high, so that the obtained lubricating oil composition has a high melting point and is used as a refrigerator working fluid. Is not preferable.

The carbonyl compound relating to the cyclic ketal or cyclic acetal used in the present invention is a ketone or aldehyde represented by the general formula (1).

[0040]

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The ketone or aldehyde represented by the general formula (1) has 2 to 37 carbon atoms, preferably 2 to 25 carbon atoms, and more preferably 2 to 17 carbon atoms. If the carbon number exceeds 37, the viscosity of the obtained cyclic ketal or cyclic acetal becomes too high, and the viscosity of the obtained lubricating oil composition becomes too high, which is not preferable.

R ¹ represents a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, preferably a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms. Group, more preferably a hydrogen atom or a linear, branched, or cyclic alkyl group having 1 to 8 carbon atoms. R ² represents a straight chain, branched chain or cyclic alkyl group having 1 to 18 carbon atoms, preferably a straight chain, branched chain or cyclic alkyl group having 1 to 12 carbon atoms, more preferably carbon number The linear, branched, or cyclic alkyl group of 1 to 8 is shown. Or R ¹
And R ² together form a carbon number of 2 to 36, preferably 2 to
24, more preferably 2 to 16 alkylene groups are shown. R ¹ and R ² may be the same or different.

If the carbon number of R ¹ or R ² exceeds 18, the viscosity of the obtained cyclic ketal or cyclic acetal becomes too high, and the viscosity of the obtained lubricating oil composition becomes too high, which is not preferable. If the alkylene group formed by R ¹ and R ² together has more than 36 carbon atoms, the viscosity of the obtained cyclic ketal or cyclic acetal becomes too high, and the viscosity of the obtained lubricating oil composition becomes too high. Therefore, it is not preferable.

Specifically, as the ketone in which R ¹ and R ² are alkyl groups, acetone, methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl butyl ketone, methyl isobutyl ketone, methyl-tert-
Butyl ketone, methyl amyl ketone, ethyl butyl ketone, dipropyl ketone, methyl hexyl ketone, ethyl pentyl ketone, 4-methyl-3-heptanone, 2-methyl-3
-Heptanone, methyl cyclohexyl ketone, ethyl hexyl ketone, dibutyl ketone, methyl octyl ketone, methyl nonyl ketone, dipentyl ketone, dihexyl ketone, 6,10-dimethyl-2-undecanone, methyl tridecyl ketone, diheptyl ketone, methyl tetradecyl ketone , Dioctyl ketone, methyl pentadecyl ketone, diisooctyl ketone, methyl hexadecyl ketone, 6,10,14-trimethyl-2-pentadecanone, dinonyl ketone, methyl heptadecyl ketone, methyl octadecyl ketone, didecyl ketone and the like.

Further, as the ketone in which R ¹ and R ² combine to form an alkylene group, cyclopentanone, cyclohexanone, 3-methylcyclopentanone, 3-methylcyclohexanone, cycloheptanone, 2,4- Examples thereof include dimethylcyclohexanone, 4-ethylcyclohexanone, 3,5,5-trimethylcyclohexanone, 4-tert-butylcyclohexanone, cyclodecanone and cyclododecanone.

Examples of the aldehyde in which R ¹ is a hydrogen atom include acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, 2-methylbutyraldehyde, caproaldehyde, 2-methylpentanal, 2-ethylbutanal, cyclopentyl. Acetaldehyde, heptanal, 2-methylhexanal, 3-methylhexanal, 2-ethylpentanal, cyclohexylaldehyde, octanal, 2-ethylhexanal, nonylaldehyde, 3,5,5-trimethylhexanal, decylaldehyde, isodecylaldehyde, 3 , 7-Dimethyloctanal, undecanol, dodecanol, tridecylaldehyde, isotridecylaldehyde, hexadecanol, isooctadecanal, octadecanol, 2-
Examples include methyl octadecanal.

When the lubricating oil composition of the present invention is used as a base oil for a working fluid of a refrigerator, a ketone or an aldehyde represented by the general formula (2) in the general formula (1) is preferable.

[0048]

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The ketone or aldehyde represented by the general formula (2) has 2 to 14 carbon atoms, preferably 2 to 11 carbon atoms, and more preferably 2 to 6 carbon atoms. When the number of carbon atoms exceeds 14, compatibility of the resulting lubricating oil composition with hydrofluorocarbon is deteriorated, which is not preferable.

R ³ represents a hydrogen atom or a straight chain, branched chain or cyclic alkyl group having 1 to 12 carbon atoms, preferably a hydrogen atom or a straight chain, branched chain or cyclic alkyl group having 1 to 8 carbon atoms. Group, and more preferably a hydrogen atom or a linear, branched, or cyclic alkyl group having 1 to 5 carbon atoms. R ⁴ represents a straight chain, branched chain or cyclic alkyl group having 1 to 12 carbon atoms, preferably a straight chain, branched chain or cyclic alkyl group having 1 to 8 carbon atoms, and more preferably carbon number 1 to 5 straight chain, branched chain,
Alternatively, it represents a cyclic alkyl group. Or R ³ and R
⁴ together represents an alkylene group having 2 to 13 carbon atoms, preferably an alkylene group having 4 to 10 carbon atoms, and more preferably an alkylene group having 4 to 5 carbon atoms. The total carbon number of R ³ and R ⁴ is 1 to 13, preferably 1 to 1.
It is 0, and more preferably 1 to 5.

When the carbon number of R ³ or R ⁴ exceeds 12, the compatibility of the resulting lubricating oil composition with hydrofluorocarbon is deteriorated, which is not preferable. In addition, the number of carbon atoms of the alkylene group formed by R ³ and R ^{4 taken} together is 1
When it exceeds 3, compatibility of the resulting lubricating oil composition with hydrofluorocarbon deteriorates, which is not preferable. Further, if the total carbon number of R ³ and R ⁴ exceeds 13, the compatibility of the resulting lubricating oil composition with hydrofluorocarbon is deteriorated, which is not preferable.

From the compatibility of the resulting lubricating oil composition with hydrofluorocarbon, the alkyl groups of R ³ and R ⁴ preferably have a branched or cyclic structure rather than a linear structure.
It is preferred that R ³ and R ⁴ do not form together rather than form an alkylene group.

The ketones represented by the general formulas (1) and (2) used in the lubricating oil composition of the present invention are high-temperature decarboxylation dimerization reaction of fatty acids, catalytic oxidation reaction of olefins (Wacker method) and secondary reaction. It can be easily obtained by oxidation of alcohol, dehydrogenation or oxidation of cycloalkane. In the case of the Wacker method, the obtained ketone can be separated and purified into a single product by precision distillation.

The aldehydes represented by the general formulas (1) and (2) used in the lubricating oil composition of the present invention include, for example, dehydrogenation reaction of fatty alcohol, hydroformylation reaction of olefin (oxo method), and fatty acid chloride. It can be easily obtained by direct reduction of Rosemund or direct fatty acid. In the case of the oxo method, a straight chain and a branched chain are produced,
It can be separated and purified into a single product by precision distillation.

The reactive derivative of the carbonyl compound used in the synthesis of the cyclic ketal or cyclic acetal in the present invention is easily synthesized from the above-mentioned ketone, aldehyde and lower alcohol having 1 to 6 carbon atoms by an acid catalyst. There are ketals and acetals. Specific examples of the lower alcohol having 1 to 6 carbon atoms include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, tert-butanol, amyl alcohol, isoamyl alcohol,
Neopentyl alcohol, 1-methylbutanol, 1,1-dimethylpropanol, 1-ethylpropanol, hexanol, isohexanol, 2-ethylbutanol, 1-methylamyl alcohol, 1,3-dimethylbutanol, 1-ethylbutanol, etc. Can be mentioned.

The cyclic ketal and cyclic acetal used in the lubricating oil composition of the present invention can be obtained as follows. The polyhydric alcohol and the above ketone, aldehyde or ketal or acetal which is a reactive derivative thereof,
As a catalyst, an acid catalyst such as paratoluenesulfonic acid, methanesulfonic acid, and sulfuric acid is added to the polyhydric alcohol in an amount of 0.05.
-10 mol%, preferably 0.1-7.0 mol%, more preferably 0.5-5.0 mol% are used for the reaction. This reaction is carried out without solvent, or in an inert solvent such as xylene, toluene, benzene, octane, isooctane, heptane, hexane, cyclohexane, pentane, ligroin, petroleum ether, or in a mixed solution thereof, the ketone, aldehyde or Depending on the boiling points of these reactive derivatives, ketals, acetals and the lower alcohols produced, 20 to 160 ° C., preferably 40 to 1
At a temperature of 30 ° C, more preferably 60 to 100 ° C,
It is preferable to remove water and lower alcohol produced. In some cases, it is effective to carry out the reaction under reduced pressure. If the temperature is lower than this, the reaction does not proceed, and if the temperature is higher than this, coloring is severe and side reactions occur, which is not preferable. Further, under a nitrogen flow condition, either under a nitrogen atmosphere or under a dry air atmosphere may be used. The reaction time may vary depending on various conditions, but usually 5 to 200 hours is preferable when using a ketone and a ketal, and 1 to 1 when using an aldehyde and an acetal.
30 hours is preferred. The obtained cyclic ketal and cyclic acetal can be purified by neutralization, pretreatment such as filtration and washing, and then operations such as clay treatment, crystallization and distillation.

The ratio of a ketone or a ketal which is a reactive derivative of a ketone or an aldehyde or an acetal (hereinafter abbreviated as a carbonyl compound) which is a reactive derivative of an aldehyde to be reacted with a polyhydric alcohol is 1 mole of the polyhydric alcohol. The carbonyl compound is A / 2 mol (A is the valence of the polyhydric alcohol). In order to accelerate the reaction rate, it is also effective to carry out the reaction by using an excess of carbonyl compound over A / 2 mol and recover the excess carbonyl compound after the reaction is completed.

The cyclic ketal or cyclic acetal used in the lubricating oil composition of the present invention is a reaction of at least one polyhydric alcohol with at least one ketone or a ketal which is a reactive derivative of a ketone, or an aldehyde or an aldehyde. It can be obtained by reacting with an acetal which is a sex derivative. Further, the cyclic ketal or cyclic acetal obtained here can be mixed and used. For example, a cyclic ketal obtained from 1 mol of sorbitol and 3 mol of methyl ethyl ketone (viscosity at 40 ° C. 63.1).
mm ² / s), a cyclic ketal obtained from 1 mol of diglycerin and 2 mol of methyl ethyl ketone (viscosity at 40 ° C. 7.6)
9 mm ² / s) can be synthesized individually and mixed to adjust the desired viscosity. As a concrete example,
The lubricating oil of VG22 can be obtained by mixing 1 mol of cyclic ketal obtained from 1 mol of sorbitol and 3 mol of methyl ethyl ketone and 1 mol of cyclic ketal obtained from 1 mol of diglycerin and 2 mol of methyl ethyl ketone. Alternatively, 1 mol of sorbitol, 1 mol of diglycerin and 5 mol of methyl ethyl ketone can be reacted to obtain the above mixture. Also, by reacting 1 mol of sorbitol with 2 kinds of ketones or aldehydes, for example, 2 mol of 3,5,5-trimethylhexanal and 1 mol of methyl ethyl ketone,
It is also possible to obtain the cyclic ketal or cyclic acetal used in the lubricating oil composition of the present invention.

Here, examples of the combination of the polyhydric alcohol and the carbonyl compound include the following. (A) One or more polyhydric alcohols having an even valence of 4 or more and 10 or less, and one or more carbonyl compounds represented by the general formula (1) or a ketal or acetal which is a reactive derivative thereof. . (B) One or more polyhydric alcohols having an even valence of 4 or more and 8 or less, and one or more carbonyl compounds represented by the general formula (2) or a ketal or acetal which is a reactive derivative thereof. . (C) One or more tetravalent or hexavalent saturated aliphatic alcohol having 4 to 20 carbon atoms and a carbonyl compound represented by the general formula (2) or a ketal or acetal which is a reactive derivative thereof.

Further, it is preferable that the amount of unreacted hydroxyl groups present in the obtained cyclic ketal or cyclic acetal is small, and such unreacted hydroxyl groups are on average 20 with respect to the number of hydroxyl groups of the polyhydric alcohol as the raw material. % Or less, preferably 10% or less, more preferably 5% or less, particularly preferably 3% or less. If more than 20% of unreacted hydroxyl groups remain, the viscosity becomes too high, and the boiling point and the flash point become too low, which is not preferable.

When the lubricating oil composition of the present invention is used as a base oil for a working fluid of a refrigerator, it is preferable that the unreacted hydroxyl group of the cyclic ketal or cyclic acetal is as small as possible.
% Or less, preferably 5% or less, more preferably 3% or less, particularly preferably 2% or less, most preferably 1% or less. If more than 10% of unreacted hydroxyl groups remain, the compatibility with hydrofluorocarbons and the electrical insulation are poor, which is not preferable.

When the lubricating oil composition of the present invention is used as an electric insulating oil or a base oil of a working fluid of a refrigerator, a polyhydric alcohol related to a cyclic ketal or a cyclic acetal has a structure not having an ether bond. It is preferable because it has high insulation. Therefore, it is better to use a cyclic ketal or a cyclic acetal obtained from a hexavalent alcohol such as sorbitol, mannitol, galactitol, iditol, talitol, and allitol, or a polyhydric alcohol such as erythritol, and an ether such as diglycerin or ditrimethylolpropane. It is more preferable to use a cyclic ketal or a cyclic acetal obtained from an alcohol having one bond.

When the lubricating oil composition of the present invention is used as an electric insulating oil or a base oil for a working fluid of a refrigerator, the cyclic ketal or cyclic acetal used has a 1,3-dioxolane structure and / or a 1,3-dioxane structure. It is preferable to include the above because it has high electric insulation. Among these, those containing a 1,3-dioxolane structure are particularly preferable. Therefore, erythritol, diglycerin, sorbitol, mannitol,
It is preferable to use an alcohol having a hydroxyl group at an adjacent position such as galactitol, iditol, talitol, and allitol.

Further, when a hexavalent alcohol such as sorbitol, mannitol, galactitol, iditol, taritol, and allitol is used, cyclic ketals represented by the general formula (3) (general formulas (3a) and (3b)) and Although a cyclic acetal can be obtained, the general formula (3a) having three 1,3-dioxolane structures is preferable because the electric insulation is higher. Further, when erythritol is used, a cyclic ketal or a cyclic acetal represented by the general formula (4) (general formulas (4a) and (4b)) can be obtained.
The general formula (4a) having a 1,3-dioxolane structure is preferable because it has higher electric insulation. Hexahydric alcohols such as sorbitol, mannitol, galactitol, iditol, talitol, and allitol, and erythritol can be reacted with a ketone or a ketal to give a compound represented by the general formula (3).
a), the cyclic ketal of the general formula (4a) is easily generated,
When reacted with an aldehyde or an acetal, the cyclic acetal of the general formula (3b) or the general formula (4b) is easily generated. Therefore, it is preferable to react these alcohols with ketones or ketals.

[0065]

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(In the formula, R ³ is a hydrogen atom or a carbon number of 1 to
12 represents a straight chain, branched chain or cyclic alkyl group, and R ⁴ represents a straight chain, branched chain or cyclic alkyl group having 1 to 12 carbon atoms. Alternatively, R ³ and R ⁴ together represent an alkylene group having 2 to 13 carbon atoms. R ³ and R
The total carbon number of ⁴ is 1 to 13. ) The specific examples of R ³ and R ⁴ are the same as the specific examples of R ³ and R ⁴ in the general formula (2).

When the lubricating oil composition of the present invention is used as a base oil for a working fluid of a refrigerator, even if the valence of the polyhydric alcohol relating to the cyclic ketal or the cyclic acetal is even, it is represented by the general formula (3). Cyclic ketals or cyclic acetals of hexavalent alcohols and cyclic ketals or cyclic acetals obtained from tetrahydric alcohols such as erythritol, diglycerin, and ditrimethylolpropane represented by the general formulas (4) to (6) are in phase with hydrofluorocarbons. It is particularly preferable from the standpoint of balancing various physical properties such as solubility, electric insulation, melting point and viscosity. Even with the same tetrahydric alcohol, the cyclic ketal having good symmetry represented by the formula (9a) or the formula (9b), which is obtained from pentaerythritol, is solid at room temperature, which is not preferable. General formula (3)-
Among the compounds shown in (6), general formula (3a), general formula (3b), and general formula (4) having a 1,3-dioxolane structure
a) and the compounds represented by the general formula (5) are preferable, and among them, the general formula (3) having only a 1,3-dioxolane structure is particularly preferable.
a), the compounds represented by the general formula (4a) and the general formula (5), and among them, the compounds represented by the general formula (3a) and the general formula (4a) in which the polyhydric alcohol moiety does not have an ether bond are preferable.

[0068]

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(In the formula, R ³ is a hydrogen atom or a carbon number of 1 to
12 represents a straight chain, branched chain or cyclic alkyl group, and R ⁴ represents a straight chain, branched chain or cyclic alkyl group having 1 to 12 carbon atoms. Alternatively, R ³ and R ⁴ together represent an alkylene group having 2 to 13 carbon atoms. R ³ and R
The total carbon number of ⁴ is 1 to 13. ) The specific examples of R ³ and R ⁴ are the same as the specific examples of R ³ and R ⁴ in the general formula (2).

The melting point of the cyclic ketal or cyclic acetal used in the lubricating oil composition of the present invention is preferably 10 ° C or lower, more preferably -10 ° C or lower, and particularly preferably-
It is 30 ° C or lower. The cyclic ketal or cyclic acetal having a melting point of higher than 10 ° C., such as the compound represented by the formula (9a) or the formula (9b), is another cyclic ketal, cyclic acetal or polyalkylene glycol compound used in the present invention having a low melting point, or It can be used by mixing with other lubricating oils and limiting the addition amount.

[0071]

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The cyclic ketal or cyclic acetal used in the lubricating oil composition of the present invention has a viscosity of 1 mm ² / s at 100 ° C.
It is preferably 100 mm ² / s or less, more preferably 1 mm ² / s or more and 50 mm ² / s or less, and particularly preferably 1 m.
It is not less than m ² / s and not more than 30 mm ² / s.

When the cyclic ketal or cyclic acetal used in the lubricating oil composition of the present invention is used as the base oil of the working fluid of the refrigerator, it is desirable that the two-phase separation temperature from the hydrofluorocarbon is low and 10 ° C. or less. , Preferably 0 ° C. or lower, more preferably −10 ° C. or lower, particularly preferably −30 ° C. or lower. However, even if a cyclic ketal or a cyclic acetal having a two-phase separation temperature from the hydrofluorocarbon exceeding 10 ° C. is mixed with other cyclic ketals, cyclic acetals, polyalkylene glycol compounds, or other hydrofluorocarbons of lubricating oil. When the two-phase separation temperature is low and the lubricating oil composition has a temperature of 10 ° C. or less, a composition for a refrigerator working fluid even if the cyclic ketal or cyclic acetal has a two-phase separation temperature with hydrofluorocarbon of more than 10 ° C. Can be used for.

2. Polyalkylene glycol compound
There are (1) a polyalkylene glycol compounds used in the embodiment the present invention the polyalkylene glycol compound has a kinematic viscosity at 100 ° C. is 0.1 to 100 mm ² /
s is a polyalkylene glycol compound. Examples of the polyalkylene glycol compound used in the present invention include compounds represented by the following general formula (7).

A- (O- (R ⁵ O) v-R ⁶ ) w (7) (In the formula, R ⁵ represents a linear or branched alkylene group having 2 to 4 carbon atoms. R ⁶ represents a hydrogen atom. Represents a hydrocarbon group having 1 to 18 carbon atoms or an acyl group having 2 to 18 carbon atoms, A represents a hydrogen atom, a w-valent alcohol residue having 1 to 18 carbon atoms, or a w-valent having 6 to 18 carbon atoms. Represents a phenol residue of, where v is 1 to
The number of 50 and w represent the number of 1 to 6. However, v R ⁵
O, w R ⁶ and w O— (R ⁵ O) v—R ⁶ may be the same or different. )

Here, R ⁵ is specifically an ethylene group,
Examples thereof include a propylene group, a trimethylene group, a butylene group, an isobutylene group and a tetramethylene group. From the viewpoint of lowering hygroscopicity, the number of carbon atoms is preferably 2 or more, and particularly preferably 3 or 4. From the viewpoint of increasing the viscosity index and improving the solubility of contaminants, the number of carbon atoms is preferably 4 or less, and particularly preferably 2 or 3.

When R ⁶ is a hydrocarbon group or an acyl group, the number of carbon atoms thereof is preferably 18 or less from the viewpoint of viscosity index and compatibility with hydrofluorocarbon. Among them, the hydrocarbon group preferably has 1 to 15 carbon atoms, and particularly preferably 1 to 13 carbon atoms. The acyl group preferably has 2 to 15 carbon atoms, and has 5 carbon atoms.
Those of 9 to 9 are particularly preferable. On the other hand, R ⁶ is preferably a hydrogen atom, a hydrocarbon group having 18 or less carbon atoms, or an acyl group from the viewpoint of the solubility of contaminants. Among them, hydrogen atom,
A hydrocarbon group having 1 to 15 carbon atoms and an acyl group having 2 to 15 carbon atoms are more preferable, and a hydrogen atom, a hydrocarbon group having 1 to 13 carbon atoms and an acyl group having 5 to 9 carbon atoms are particularly preferable. Therefore, an alkyl group and an acyl group are preferable from the viewpoint of viscosity index and compatibility with hydrofluorocarbons, and a hydrogen atom, an alkyl group, and an acyl group are preferable from the viewpoint of contamination solubility, and they can be selectively used depending on the required problem. is there. In order to satisfy both performances, R ⁶ preferably has 1 to 18 carbon atoms, more preferably 1 to 15 carbon atoms,
Particularly preferably, it is an alkyl group having 1 to 13 carbon atoms.

Examples of the hydrocarbon group for R ⁶ include the following alkyl groups and aryl groups. Alkyl group: methyl group, ethyl group, propyl group, isopropyl group, butyl group, 1-methylpropyl group, 2-methylpropyl group, t-butyl group, pentyl group, 2-methylbutyl group, 3-methylbutyl group, 1- Ethylpropyl group, 1,1-dimethylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group, cyclopentyl group, hexyl group, 2-methylpentyl group, 2-ethylbutyl group, 2,3-dimethyl Butyl group, cyclohexyl group, heptyl group, 2-methylhexyl group, 3-methylhexyl group, 2-ethylpentyl group, octyl group, 2-methylheptyl group, 2-ethylhexyl group, 3,5-dimethylhexyl group, nonyl Group, 3,5,5-trimethylhexyl group, decyl group, 2,4,6-trimethylheptyl group, undecyl group, - methyldecyl group, a dodecyl group,
2-methylundecyl group, 1- (2'-methylpropyl) -3,5-dimethylhexyl group, tridecyl group,
2,4,6,8-tetramethylnonyl group, 2-methyldodecyl group, tetradecyl group, 2-methyltridecyl group,
2- (3'-methylbutyl) -7-methyloctyl group,
2- (1'-methylbutyl) -5-methyloctyl group,
Pentadecyl group, 2-methyltetradecyl group and the like.

Aryl group: 4-methylphenyl group, 4-
Ethylphenyl group, 4-t-butylphenyl group, 2,4
-Di-t-butylphenyl group, 2,6-di-t-butylphenyl group, 2,6-di-t-butyl-4-methylphenyl group, 4-nonylphenyl group, phenyl group, naphthyl group and the like.

Further, examples of the acyl group of R ⁶ include the following. Acetic acid, propionic acid, butyric acid, valeric acid, isovaleric acid, 2-methylbutyric acid, caproic acid, 2-ethylbutyric acid, enanthic acid, 2-ethylpentanoic acid, 2-methylhexanoic acid, 3-methylhexanoic acid, caprylic acid, Acyl groups of carboxylic acids such as 2-ethylhexanoic acid, 3,5-dimethylhexanoic acid, pelargonic acid, 3,5,5-trimethylhexanoic acid, decanoic acid, undecanoic acid, isotridecanoic acid, myristic acid, and isomyristic acid.

Of these, R ⁶ is preferably an alkyl group or an aryl group from the viewpoint of not producing a carboxylic acid by hydrolysis, and an alkyl group is preferred to the aryl group from the viewpoint of having a high viscosity index.

When A is an alcohol residue or a phenol residue, its carbon number is 18 or less from the viewpoint that it does not have too high a viscosity, the compatibility with hydrofluorocarbon, and the viewpoint of improving the solubility of contaminants. It is preferably 15 or less, more preferably 13 or less, still more preferably 10 or less, particularly preferably 6 or less, and most preferably 4 or less. Examples of the alcohol residue or the phenol residue of A include the following. Alcohol residue: methanol, ethanol, propanol, isopropanol, butanol, 1-methylpropanol, 2-methylpropanol, t-butanol, pentanol, 2-methylbutanol, 3-methylbutanol, 2,2-dimethylpropanol, hexanol,
2-methylpentanol, 2-ethylbutanol, 2,
3-dimethylbutanol, heptanol, 2-methylhexanol, 3-methylhexanol, 5-methylhexanol, octanol, 2-ethylhexanol, 2
-Methylheptanol, 3,5-dimethylhexanol, nonanol, 3,5,5-trimethylhexanol, decyl alcohol, 2,4,6-trimethylheptanol, undecyl alcohol, dodecyl alcohol,
Alcohol residues of monohydric alcohols such as tridecyl alcohol, 2,4,6,8-tetramethylnonanol, tetradecyl alcohol, 2-pentylnonanol and pentadecyl alcohol.

Neopentyl glycol, 2,2-diethyl-1,3-propanediol, 2-n-butyl-2-
Alcohol residues of hindered alcohols such as ethyl-1,3-propanediol, trimethylolethane, trimethylolpropane, ditrimethylolpropane, pentaerythritol and dipentaerythritol. Ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,6-hexanediol, 2-ethyl-
1,3-hexanediol, glycerin, diglycerin, triglycerin, 1,2,4-butanetriol,
Alcohol residues of polyhydric alcohols such as 1,2,6-hexanetriol, sorbitol and mannitol.

Phenol residue: phenol, 4-methylphenol, 4-ethylphenol, 4-t-butylphenol, 2,4-di-t-butylphenol, 2,6
-Phenol residues of phenols such as di-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, 4-nonylphenol, bisphenol A. In A, from the viewpoint of having a high viscosity index,
Alcohol residues are preferred over phenol residues.

Further, v is preferably a number of 1 to 50, more preferably 1 to 40, and especially 1 to 30 from the viewpoints of viscosity and hygroscopicity and improving the contamination dissolving power. w is preferably a number of 1 to 6 from the viewpoint of viscosity and the viewpoint of improving the contamination dissolving power, and particularly 1 to 6.
The number is more preferably 3, and is preferably 1 from the viewpoint of having a particularly high viscosity index and the viewpoint of improving the contamination dissolving power.

Among the compounds represented by the general formula (7), the compounds represented by the following general formula (8) are particularly preferable from the viewpoint of having a high viscosity index and the viewpoint of improving the contamination dissolving power. is there.

R ⁷ O— (R ⁵ O) x—R ⁸ (8) (In the formula, R ⁵ represents a linear or branched alkylene group having 2 to 4 carbon atoms. R ⁷ represents 1 to 18 carbon atoms. R ⁸ represents a hydrogen atom, a hydrocarbon group having 1 to 18 carbon atoms, x represents a number of 1 to 50. However, R ⁷ and R ⁸ may be the same or different. Also, x R ⁵ O
May be the same or different. )

From the viewpoint of not generating carboxylic acid by hydrolysis, from the viewpoint of viscosity index, and from the viewpoint of improving the contamination solubility, R ⁷ preferably has 18 or less carbon atoms, more preferably 1 to 15 carbon atoms, and particularly preferably 1 to 15 carbon atoms. 1-13
It is. Further, R ⁷ is preferably an alkyl group. Specific examples thereof include the alkyl group represented by R ⁶ in the general formula (7). From the viewpoint of not generating carboxylic acid by hydrolysis and the viewpoint of viscosity index, R ⁸ is preferably a hydrocarbon group, and particularly preferably an alkyl group. 1 carbon
8 or less, more preferably 1 to 15 carbon atoms,
Particularly preferably, it has 1 to 13 carbon atoms. Specific examples include the alkyl group represented by R ⁶ in the general formula (7). On the other hand, a hydrogen atom or a hydrocarbon group having 18 or less carbon atoms is preferable from the viewpoint of improving the solubility of contaminants,
More preferably, a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms, and particularly preferably a hydrogen atom or 1 to 13 carbon atoms.
Is a hydrocarbon group. The hydrocarbon group is preferably an alkyl group, specifically, R ⁶ in the general formula (7).
The alkyl groups shown in are listed. Therefore, an alkyl group is preferable from the viewpoint of not generating carboxylic acid by hydrolysis and a viewpoint of viscosity index, and a hydrogen atom and an alkyl group are preferable from a viewpoint of solubility of contaminants, and they can be used properly according to the required problems. In order to satisfy both performances, R ⁸ is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms,
An alkyl group having 1 to 13 carbon atoms is particularly preferable.

X is a number of 1 to 50, preferably 1 to
40, more preferably 1 to 30. A number of 50 or less is preferable from the viewpoint of the solubility of contaminants, the viscosity and the hygroscopicity.

When the lubricating oil composition of the present invention is used as a base oil for a working fluid of a refrigerator, particularly in the compound represented by the general formula (8), the carbon number of R ⁷ is preferably 1 to 18, more preferably 1 -15, particularly preferably 1-13.
From the viewpoint of compatibility with hydrofluorocarbons and the viewpoint of improving the solubility of contaminants, an alkyl group having 18 or less carbon atoms is preferable. When the lubricating oil composition of the present invention is used as a base oil for a working fluid of a refrigerator, R ⁸ is a hydrogen atom or a carbon number of 18 in the compound represented by the general formula (8).
The following hydrocarbon groups are preferable, a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms is more preferable, and a hydrogen atom or a hydrocarbon group having 1 to 13 carbon atoms is particularly preferable. From the viewpoint of viscosity index and compatibility with hydrofluorocarbons, an alkyl group having 18 or less carbon atoms is preferable, and from the viewpoint of solubility of contaminants, hydrogen atom and carbon number are 1
An alkyl group of 8 or less is preferable, and it can be used properly according to the required problem. In order to satisfy both performances, R ⁸ is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 15 carbon atoms, and 1 to 1 carbon atoms.
Particularly preferred is an alkyl group of 13.

The carbon number of R ⁵ is 2 or 3 only, a mixture of 2 and 3 carbons, or a carbon number of 3 or 4 from the viewpoint of compatibility with hydrofluorocarbons and the viewpoint of improving the contamination dissolving power. It is preferable to use a mixture, or a mixture of 2 to 3 and 4 carbon atoms, more preferably 2 only, 3
Only a mixture of 2 and 3.

These polyalkylene glycols can be produced, for example, as follows. By reacting water or alcohol with alkylene oxide under an alkaline catalyst such as NaOH or KOH, a monoalkyl ether type polyalkylene glycol or glycol type polyalkylene glycol can be obtained. Further, the terminal hydroxyl group is alkylated with an alkyl halide using an alkali metal as a catalyst, and is also acylated by reacting with a carboxylic acid or its methyl ester, ethyl ester, or acid anhydride to obtain a dialkyl ether type polyalkylene glycol or An ester ether type polyalkylene glycol can be obtained.

(2) Physicochemical properties of polyalkylene glycol compound (i) Kinematic viscosity The polyalkylene glycol compound used in the present invention has a kinematic viscosity at 100 ° C. of 0.1 to 100 mm ² /
s, preferably 0.5 to 50 mm ² / s, more preferably from 1 to 30 mm ² / s, particularly preferably 1~15mm
² / s is a polyalkylene glycol compound.
When the kinematic viscosity at 100 ° C. exceeds 100 mm ² / s, the viscosity of the lubricating oil composition becomes too high, which is not preferable. The kinematic viscosity at 40 ° C. is 1 to 1000 mm ² /
It is preferably s. The same applies when the lubricating oil composition of the present invention is used as a base oil for a working fluid of a refrigerator.

(Ii) Iodine Value The iodine value (Ig / 100g) of the polyalkylene glycol compound used in the lubricating oil composition of the present invention is preferably 10 or less, more preferably 5 or less, still more preferably 3
It is particularly preferably 1 or less. If the iodine value exceeds 10, the thermal oxidation stability of the resulting lubricating oil composition may be significantly impaired. When the lubricating oil composition of the present invention is used as a base oil of a refrigerator working fluid, the polyalkylene glycol compound used has an iodine value of preferably 5 or less, more preferably 3 or less, still more preferably 1 or less, and particularly preferably 0. It is 5 or less. When the iodine value exceeds 5, the thermo-oxidative stability of the working fluid of the refrigerator using the lubricating oil composition of the present invention as a base oil may be significantly impaired.

(Iii) Acid Value The acid value (mgKOH / g) of the polyalkylene glycol compound used in the lubricating oil composition of the present invention is 5 or less, preferably 1 or less, more preferably 0.5 or less, and particularly preferably. It is 0.1 or less. When the acid value exceeds 5, it not only promotes hydrolysis of the lubricating oil composition, but also impairs thermal oxidation stability of the lubricating oil composition itself, and also corrodes metallic materials, lowers the flash point, and wear resistance. It is not preferable because it causes deterioration of the electric field, an offensive odor, a decrease in electric insulation, and the like. When the lubricating oil composition of the present invention is used as a base oil for a working fluid of a refrigerator, the acid value (mgKOH / mgKOH /
g) is 1 or less, preferably 0.1 or less, more preferably 0.05 or less, and particularly preferably 0.03 or less.
If the acid value exceeds 1, corrosion of metal materials, deterioration of wear resistance,
It is not preferable because it causes deterioration of thermal oxidative stability and electric insulation.

(Iv) Hydroxyl Value The hydroxyl value (mgKOH / g) of the polyalkylene glycol compound used in the lubricating oil composition of the present invention is 0.1 to 0.1.
It is 500, preferably 0.1 to 300, more preferably 0.1 to 200. The hydroxyl value is 50 from the viewpoint of the flash point, electric insulation and viscosity index of the resulting lubricating oil composition.
0 or less is preferable, and 0.1 or more is preferable from the viewpoint of lubricity. When the lubricating oil composition of the present invention is used as a base oil for a working fluid of a refrigerator, the polyalkylene glycol compound used has a hydroxyl value (mgKOH / g) of preferably 0.1 to 500, more preferably 0.1 to 500. It is 300, more preferably 0.1 to 200. From the viewpoint of compatibility with hydrofluorocarbons and electric insulation, the hydroxyl value is 50.
0 or less is preferable, and 0.1 or more is preferable from the viewpoint of lubricity.

(V) Melting Point The melting point of the polyalkylene glycol compound used in the lubricating oil composition of the present invention is preferably 10 ° C. or lower, more preferably −10 ° C., from the viewpoint of improving the ability to dissolve contaminants.
The temperature is particularly preferably -30 ° C or lower. Melting point is 10
The polyalkylene glycol compound having a melting point of higher than 0 ° C. is a cyclic ketal or a cyclic acetal used in the present invention having a low melting point,
It can be used in a lubricating oil composition by mixing it with a polyalkylene glycol compound and limiting the amount added. Further, when the lubricating oil composition of the present invention is used as a base oil of a working fluid for a refrigerator, the melting point of the polyalkylene glycol compound used is 10 ° C. or less, preferably from the viewpoint of improving compatibility with hydrofluorocarbon and contamination dissolving power. -10 ° C or lower, more preferably -30 ° C or lower, particularly preferably -4.
0 ° C. or less.

(Vi) Two-Phase Separation Temperature When the lubricating oil composition of the present invention is used as a base oil for a working fluid of a refrigerator, it is desirable that the two-phase separation temperature of the polyalkylene glycol compound to be used and hydrofluorocarbon be low. The temperature is 10 ° C or lower, preferably 0 ° C or lower, more preferably -10 ° C or lower, and particularly preferably -30 ° C or lower. However, even if the polyalkylene glycol compound having a two-phase separation temperature with the hydrofluorocarbon exceeds 10 ° C., the two-phase separation temperature with the hydrofluorocarbon can be obtained by mixing with the polyalkylene glycol compound of the present invention, the cyclic ketal or the cyclic acetal. When the composition is lowered to 10 ° C. or lower as a composition, it can be used in a composition for a working fluid of a refrigerator.

The mixing ratio of the polyalkylene glycol compound to the cyclic ketal or cyclic acetal in the lubricating oil composition of the present invention is polyalkylene glycol compound / cyclic ketal or cyclic acetal = 1/99 to 99/1 weight ratio. , Preferably 5/95 to 95/5 weight ratio, more preferably 10/90 to 90/10 weight ratio, particularly preferably 20/80 to 80/20 weight ratio, most preferably 20 /
80 to 50/50 weight ratio. The amount of cyclic ketal or cyclic acetal contained is preferably 1% by weight or more from the viewpoint of improving electric insulation and lubricity.
From the viewpoint of improving the viscosity index and the solubility of contaminants, the content of the polyalkylene glycol compound is 1% by weight.
The above is preferred.

[0100] 3. Lubricating oil composition and working fluid for refrigerator
Composition The lubricating oil composition of the present invention is obtained by mixing the polyalkylene glycol compound as described above with a cyclic ketal or a cyclic acetal, and the resulting lubricating oil composition has a kinematic viscosity at 100 ° C. of 1 to 100 mm. ² / s is preferable, 1-50 mm ² / s is more preferable, 1-30 is particularly preferable.
mm ² / s. The kinematic viscosity at 40 ° C is 1 to 100
0 mm ² / s is preferable, more preferably 1 to 500 m
m ² / s, particularly preferably 5 to 200 mm ² / s.

The iodine value (Ig / 100 g) of the lubricating oil composition of the present invention is 10 or less, preferably 5 or less,
It is more preferably 3 or less, and particularly preferably 1 or less.
If the iodine value exceeds 10, the thermal oxidation stability of the lubricating oil composition may be significantly impaired. The acid value (mgKOH / g) of the lubricating oil composition of the present invention is 5 or less, preferably 1 or less, more preferably 0.5 or less, and particularly preferably 0.1 or less. If the acid value exceeds 5, the thermal oxidation stability of the lubricating oil composition itself is impaired, and corrosion of metal materials, lowering of the flash point, lowering of wear resistance, strange odor, lowering of electrical insulation, etc. are caused. Not preferable. The hydroxyl value (mgKOH / g) of the lubricating oil composition of the present invention is 0.1.
-100, preferably 0.1-80, more preferably 0.1-50, particularly preferably 0.1-40. The hydroxyl value is preferably 100 or less from the viewpoint of lowering the flash point and lowering the electrical insulation of the resulting lubricating oil composition. Further, from the viewpoint of lubricity, 0.1 or more is preferable. The melting point of the lubricating oil composition of the present invention is preferably 10 ° C or lower, more preferably -10 ° C or lower, and particularly preferably -30 ° C or lower.

When the lubricating oil composition of the present invention is used as a base oil for a working fluid of a refrigerator, it is desirable that the two-phase separation temperature from hydrofluorocarbon is low, 10 ° C. or lower, preferably 0 ° C. or lower, and further preferably. It is -10 ° C or lower, particularly preferably -30 ° C or lower.

The lubricating oil composition of the present invention can also be used as a mixture with other lubricating oils. Other lubricating oils include mineral oils, polybutene, poly-α-olefins, hydrocarbon synthetic oils such as alkylbenzenes, esters, polyphenyl ethers,
Carbonate, phosphate ester, silicate ester,
Silicone oil, synthetic lubricating oil such as perfluoropolyether, rapeseed oil, soybean oil, safflower oil, corn oil, coconut oil, palm oil, palm kernel oil, linseed oil, cottonseed oil, tung oil,
Examples include natural oils such as castor oil and tallow fatty acid ester. A concrete example is the "new edition of physical chemistry of lubrication" (Koshobo).
And "Basics and Applications of Lubricating Oil" (Corona).

When the lubricating oil composition of the present invention is mixed with another lubricating oil, the mixing ratio is 10% by weight or more, preferably 30% by weight or more of the lubricating oil composition of the present invention in the mixed lubricating oil. It is particularly preferable that the content of 50% by weight or more is included, and that the mixed lubricating oil contains 0.1% by weight or more, and particularly preferably 10% by weight or more of a cyclic ketal, a cyclic acetal or a polyalkylene glycol compound.

The content of the lubricating oil composition of the present invention is 10
If it is less than the weight%, the effect of improving the lubricity cannot be sufficiently exhibited. The amount of cyclic ketal, cyclic acetal or polyalkylene glycol compound contained is 0.1% by weight.
If it is less, the effect of improving the lubricity and the effect of improving the viscosity index cannot be sufficiently exerted. When the lubricating oil composition of the present invention is used as a base oil for a working fluid of a refrigerator, it is preferable that the other lubricating oil to be mixed has excellent compatibility with hydrofluorocarbons, such as ester, perfluoropolyether, carbonate and perfluoropolyether. Fluoroesters and the like are preferred. However, when the compatibility of the lubricating oil composition of the present invention with hydrofluorocarbon is sufficiently excellent, for example, when the two-phase separation temperature is −30 ° C. or lower, preferably −50 ° C. or lower, the phase with hydrofluorocarbon is increased. It is also possible to mix with a lubricating oil having poor solubility, such as alkylbenzene or mineral oil, within the range where the two-phase separation temperature does not exceed 10 ° C.

The lubricating oil composition of the present invention contains, if necessary, antioxidants, extreme pressure agents, oiliness improvers, defoamers, detergent dispersants, viscosity index improvers, rust preventives, etc. Lubricating oil additives such as demulsifiers can also be added. For example, those usable as antioxidants are 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, 4,
Phenolic antioxidants such as 4'-methylenebis (2,6-di-tert-butylphenol), p, p-dioctylphenylamine, monooctyldiphenylamine, phenothiazine, 3,7-dioctylphenothiazine, phenyl-1-naphthylamine Amine-based antioxidants such as phenyl-2-naphthylamine and alkylphenyl-2-naphthylamine,
Examples thereof include sulfur-based antioxidants such as alkyl disulfide, thiodipropionic acid ester and benzothiazole, zinc dialkyldithiophosphate, zinc diaryldithiophosphate and the like. The amount added is 0.05 to 2.0% by weight based on the lubricating oil containing the lubricating oil composition of the present invention.

Examples of the extreme pressure agent and oiliness improver that can be used include zinc compounds such as zinc dialkyldithiophosphate and zinc diaryldithiophosphate, thiodipropionic acid esters, dialkyl sulfides, dibenzyl sulfides, dialkyl polysulfides and alkyls. Sulfur compounds such as mercaptan, dibenzothiophene and 2,2'-dithiobis (benzothiazole), phosphorus compounds such as triaryl phosphate, triaryl phosphite, trialkyl phosphite and trialkyl phosphate, chlorine such as chlorinated paraffin Compound, molybdenum dithiocarbamate, molybdenum dithiophosphate,
Examples thereof include molybdenum compounds such as molybdenum disulfide, perfluoroalkyl polyethers, ethylene trifluoride chloride polymers, fluorine compounds such as fluorinated graphite, silicon compounds such as fatty acid-modified silicone, and graphite. The amount added is 0.0 with respect to the lubricating oil containing the lubricating oil composition of the present invention.
5 to 10% by weight.

As the defoaming agent, silicone oil such as dimethylpolysiloxane and organosilicates such as diethyl silicate are used. The amount added is 0.0005 to 5 with respect to the lubricating oil containing the lubricating oil composition of the present invention.
1% by weight.

The detergents and dispersants used are sulfonates, phenates, salicylates, phosphonates, polybutenyl succinimides, polybutenyl succinates and the like. The amount added is 0.05 to 10% by weight based on the lubricating oil containing the lubricating oil composition of the present invention.

When the lubricating oil composition of the present invention is used as a base oil for a working fluid of a refrigerator, benzotriazole or its derivative for protecting a metal surface is added as an additive, and lubricity is improved. It is effective to add triaryl phosphate or triaryl phosphite, or to add a phenolic compound having a radical trapping ability for improving thermal stability and a metal deactivator having a chelating ability.

The triaryl phosphate and triaryl phosphite used in the present invention have 18 to 18 carbon atoms.
70, more preferably 18 to 50 carbon atoms. Specifically, it is described in JP-A-5-209171, column 12, lines 26-41. Among them, particularly preferred is triphenyl phosphate,
Tricresyl phosphate, trixylenyl phosphate, tris (2,4-di-tert-butylphenyl) phosphate, triphenyl phosphite, tricresyl phosphite, trixylenyl phosphite, tris (2,4 -Di-tert-butylphenyl) phosphite. The amount of triaryl phosphate and / or triaryl phosphite added is 0.1 to 5.0% by weight, and preferably 0.5 to 2.%, based on the lubricating oil containing the lubricating oil composition of the present invention. It is 0% by weight.

The amount of benzotriazole or its derivative used in the present invention is 0.001 to 0.1% by weight, preferably 0.003 to 0.1% by weight, based on the lubricating oil containing the lubricating oil composition of the present invention. It is 0.03% by weight. The benzotriazole and benzotriazole derivative used in the present invention have 6 to 50 carbon atoms, preferably 6 to 30 carbon atoms. Specifically, Japanese Patent Laid-Open No. 5-2
09171, column 13, lines 9 to 29. Among them, benzotriazole and 5-methyl-1H-benzotriazole are particularly preferable.

The addition amount of the metal deactivator used in the present invention is 0. 0 based on the lubricating oil containing the lubricating oil composition of the present invention.
001 to 2.0% by weight, preferably 0.003 to
0.5% by weight. The metal deactivator used in the present invention preferably has a chelating ability and has 5 to 5 carbon atoms.
It is 0, preferably 5 to 20. Specifically, it is described in JP-A-5-209171, column 13, line 38 to column 14, line 8. Among them, particularly preferred are N, N'-disalicylidene-1,2-diaminoethane, N, N'-disalicylidene-1,2-diaminopropane, acetylacetone, acetoacetate, alizarin, quinizarin and the like.

The amount of the phenolic compound having a radical trapping ability used in the present invention is 0.05 to 2.0% by weight, preferably 0, based on the lubricating oil containing the lubricating oil composition of the present invention. 0.05 to 0.5% by weight. The phenolic compound used in the present invention has 6 to 100 carbon atoms, preferably 10 to 80 carbon atoms.
belongs to. Specifically, it is described in JP-A-5-209171, column 12, line 32 to column 13, line 18. Among them, particularly preferable are 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, 4,4′-methylenebis (2,6-di-tert-butylphenol), 4,4'-Butylidene bis (3-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-ter
t-butylphenol), 2,2'-methylenebis (4-methyl)
-6-tert-butylphenol), 4,4'-isopropylidenebisphenol, 2,4-dimethyl-6-tert-butylphenol, tetrakis [methylene-3- (3,5-di-tert-butyl-4)
-Hydroxyphenyl) propionate] methane, 1,1,
3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-
Di-tert-butyl-4-hydroxybenzyl) benzene, 2,
6-di-tert-butyl-4-ethylphenol, 2,6-bis (2 '
-Hydroxy-3'-tert-butyl-5'-methylbenzyl) -4
-Methylphenol, bis [2- (2-hydroxy-5-methyl-3-tert-butylbenzyl) -4-methyl-6-tert-butylphenyl] terephthalate, triethyleneglycol-
Bis [3- (3,5-di-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol
-Bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate and the like.

Further, an additive such as an organic tin compound or a boron compound, which stabilizes the chlorofluorocarbon refrigerant, may be added. The amount added is 0.0 with respect to the lubricating oil containing the lubricating oil composition of the present invention.
01 to 10% by weight.

Since the lubricating oil composition of the present invention has excellent compatibility with hydrofluorocarbons and excellent electrical insulation properties, it can be used as a working fluid for a refrigerator as a mixture with hydrofluorocarbons. Further, since it has excellent electric insulation properties, it can be used as electric insulating oil, transformer oil, and the like. Further, since the composition has a ring structure, it can be used as a traction oil. Further, since it has excellent lubricity and heat resistance, it can be used as engine oil, turbine oil, gear oil, hydraulic oil, bearing oil, metal working oil, compressor oil, grease base oil and the like. Further, since it has excellent lubricity, it can be used as an additive for low-sulfur gas oil.
When the lubricating oil composition of the present invention is used as a refrigerator working fluid,
When the lubricating oil composition of the present invention is mixed with another lubricating oil, the mixing ratio of the lubricating oil composition of the present invention in the mixed lubricating oil is 10% by weight or more, preferably 30% by weight or more, and particularly preferably. 50% by weight or more, and 0.1% by weight or more of cyclic ketal or cyclic acetal in the mixed lubricating oil,
It is particularly preferable that the content is 10% by weight or more.

When the lubricating oil composition of the present invention is used in a refrigerator working fluid, the ratio of hydrofluorocarbon to the refrigerating machine oil containing the lubricating oil composition of the present invention in the refrigerator working fluid composition of the present invention is Normal hydrofluorocarbon / refrigerating machine oil = 50/1 to 1/20 (weight ratio), preferably 1
It is 0/1 to 1/5 (weight ratio). Hydrofluorocarbon / refrigerating machine oil = 50/1 If the ratio of hydrofluorocarbon becomes higher, hydrofluorocarbon-
The viscosity of the refrigerating machine oil mixed solution becomes low and the lubricity may deteriorate, which is not preferable. If the ratio of hydrofluorocarbon is lower than hydrofluorocarbon / refrigerating machine oil = 1/20, the refrigerating capacity may be insufficient, which is not preferable.

The hydrofluorocarbons used in the present invention include difluoromethane (HFC32), 1,1-difluoroethane (HFC152a), 1,1,1-trifluoroethane (HFC143a) and 1,1,1,2-tetrafluorocarbon. Ethane (HFC134a), 1,1,2,2-Tetrafluoroethane (HFC134), Pentafluoroethane (HFC12)
5) etc., and particularly 1,1,1,2-tetrafluoroethane, difluoromethane, pentafluoroethane, and 1,1,1-trifluoroethane are preferable. These hydrofluorocarbons may be used alone, or two or more kinds of hydrofluorocarbons may be mixed and used. In the present invention, the contaminants having the effect of improving the dissolving power are: 1) a compound in which the refrigerating machine oil is deteriorated by heat, air or hydrolysis in the refrigerating cycle, and 2) a drawing oil or cutting oil used in manufacturing and assembling the refrigerator. , Anti-rust oil,
Process chemicals such as press oil and cleaning liquid, etc. 3) These process chemicals are compounds and the like deteriorated by heat and air hydrolysis in the refrigeration cycle.

[0119]

EXAMPLES The production examples and examples of the present invention will be described below, but the present invention is not limited thereto.

Production Example 1 A 3-liter four-necked flask was equipped with a stirrer, a thermometer, a nitrogen blowing tube, and a dehydration tube equipped with a condenser. D-
Sorbitol 336.8 g (1.85 mol), methyl ethyl ketone 800.0 g (11.1 mol), paratoluene sulfonic acid monohydrate 17.6 g (0.092 mo)
1) and 200 ml of hexane were charged into the flask. The reaction was carried out at 69 to 79 ° C under a nitrogen atmosphere at atmospheric pressure for 8 hours while distilling off water. After completion of the reaction, the mixture was cooled to 60 ° C., 19.6 g of sodium carbonate (0.185 mol, twice equivalent of paratoluenesulfonic acid) was added for neutralization, and 6
Stirred at 0 ° C. for 30 minutes. Add 200g of water, 60 ℃
After stirring for 30 minutes, the mixture was allowed to stand and separated into layers. After removing the lower layer, the solution was washed with 200 g of saturated saline, and hexane and excess methyl ethyl ketone were removed under reduced pressure using a rotary evaporator. Further, it was distilled under reduced pressure to obtain a crude cyclic ketal. Then, a part of the crude cyclic ketal is further purified by column chromatography to give a cyclic ketal A.
(Hydroxyl value 4.6 mg KOH / g, gas chromatography purity 99.1%) was obtained.

Further, cyclic acetal B was prepared by the same method using D-sorbitol and isobutyraldehyde.
(Hydroxyl value 6.0 mg KOH / g, gas chromatography purity 99.0%) was obtained.

In addition, polyalkylene glycol compounds a to o shown below were obtained by a conventional method. _{a: CH 3 O (PO)} 32 CH 3 b: n-C 4 H 9 O (PO) 19.4 H c: compound represented by the following general formula (10)

[0123]

Embedded image

(Wherein v ₁ + v ₂ + v ₃ + v ₄ + v ₅ +
v ₆ = 17, R is hydrogen atom / CH ₃ CH ₂ CH ₂
CH ₂ = 3/3. )

D: nC ₄ H ₉ O (PO) ₅ CH ₃ e: nC ₈ H ₁₇ O (PO) _4.6 CH ₃ f: nC ₄ H ₉ O (PO) _5.5 CH ₂ CH ₂ CH ₂ C
_{H 3 g: n-C 12} H 25 O (EO) 9 H h: CH 3 O (PO) 24 (EO) 6 H i: CH 3 O (PO) 24 (EO) 6 CH 3 j: n-C _{4 H 9 O (EO / PO} = 1.6 / 1.6) H k: n-C 12 H 25 O (PO) 2 (EO) 6 H l: n-C 12 H 25 O (EO) 6 ( _{PO) 2 H m: n-} C 12 H 25 O (EO / PO = 5/2) H n: iso-C 13 H 27 O (PO) 5 (EO) 8 H o: iso-C 13 H 27 O (PO) ₇ (EO) ₁₁ H (where EO represents an oxyethylene group and PO represents an oxypropylene group, and the number of moles added is the average composition. Compound j
And m are random types. n- represents a straight chain and iso- represents a branched chain. )

The cyclic ketals, cyclic acetals and polyalkylene glycol compounds obtained in Production Examples have kinematic viscosities at 40 ° C. and 100 ° C. (JIS K-2283), pour point (JIS K-2269), acid value, hydroxyl value ( JIS
K-2501) is shown in Table 1. Table 2 also shows oils (a) to (c) used as comparative products.

[0127]

[Table 1]

[0128]

[Table 2]

Example 1 Lubricating oil compositions 1 to 25 and comparative product 1 of the present invention obtained by using the cyclic ketals, cyclic acetals and polyalkylene glycol compounds used in the present invention products obtained in the production examples
Kinematic viscosity of 40 to 100 ° C. (JIS K-2
283), viscosity index (JIS K-2283), 25 ° C
The volume resistivity (JIS C-2101) was measured. Tables 3 to 5 show the results.

[0130]

[Table 3]

[0131]

[Table 4]

[0132]

[Table 5]

As is clear from the above results, the product of the present invention has improved viscosity index and volume resistivity. On the other hand, Comparative Products 1 and 2 are excellent in volume resistivity but inferior in viscosity index, and Comparative Products 3 to 17 are excellent in viscosity index but inferior in volume resistivity.

Example 2 Lubricating oil compositions 2, 3, 6, 7 of the present invention and Comparative product 3,
The hygroscopicity of No. 4 was examined. Inner diameter 18 mm, inner volume 10
2 g of oil whose water concentration was adjusted to 50 ppm or less was taken in a ml glass tube and placed in a constant temperature bath at 25 ° C. and a humidity of 80%. After standing for a certain period of time, the water concentration of the oil was measured by the Karl Fischer method (JIS K-2275). Table 6 shows the results. As is clear from Table 6, the product of the present invention had much lower hygroscopicity than the comparative product (polyalkylene glycol alone).

[0135]

[Table 6]

Example 3 The compatibility of the lubricating oil composition of the present invention and the oils a to c used in the comparative product with hydrofluorocarbon as a refrigerant was examined. The product of the present invention (lubricating oil composition), 1,1,1,2-tetrafluoroethane (HFC134a), difluoromethane (HFC32), and pentafluoroethane (HFC12)
5) mixed refrigerant or difluoromethane (HFC3
2) and a mixed refrigerant of pentafluoroethane (HFC125), which is a composition of the present invention (composition for refrigerator working fluid) 26 to 71, and oils used in comparative products shown in Table 2
C. Two-phase separation temperature at low temperature of Comparative Products 18 to 23, which is a composition of a mixed refrigerant of HFC134a, HFC32 and HFC125 or a mixed refrigerant of HFC32 and HFC125, was measured. The two-phase separation temperature was measured by setting the oil concentration in the refrigerator working fluid composition to 10, 20, 30, 40 and 50% by volume. The results are shown in Tables 7 to 10. The product of the present invention has excellent solubility in each refrigerant as compared with the comparative product.

[0137]

[Table 7]

[0138]

[Table 8]

[0139]

[Table 9]

[0140]

[Table 10]

Example 4 With respect to the lubricating oil composition of the present invention, a shield tube test was conducted under the following conditions in order to examine the thermal stability.
That is, the water concentration is 10 ppm or less and the acid value is 0.
10 g of lubricating oil adjusted to 03 (mgKOH / g) or less,
And 5g of hydrofluorocarbon in a glass tube,
Iron, copper and aluminum were added as a catalyst and the tube was sealed. 1
After testing at 75 ° C. for 14 days, the appearance of the composition of hydrofluorocarbon and oil and the presence or absence of deposits were observed, the sealed tube was opened to remove hydrofluorocarbon, and the acid value of the oil was examined. The results are shown in Tables 11 to 13. As is clear from Tables 11 to 13, all of the products of the present invention had a good appearance, no precipitate, no increase in acid value, and good thermal stability.

[0142]

[Table 11]

[0143]

[Table 12]

[0144]

[Table 13]

Example 5 With respect to the lubricating oil composition of the present invention product and the comparative products a and c shown in Table 2, a shield tube test was conducted under the following conditions in order to examine the thermal stability in the presence of water. That is,
The water concentration is 3000 ppm and the acid value is 0.03 (mg
10 g of lubricating oil adjusted to KOH / g) or less and 5 g of hydrofluorocarbon were placed in a glass tube, and iron, copper and aluminum were added as catalysts and the tube was sealed. 2 at 175 ° C
After testing for 8 days, the appearance of the composition of hydrofluorocarbon and oil and the presence or absence of deposits were observed, the sealed tube was opened to remove the hydrofluorocarbon, and the acid value of the oil was examined. The results are shown in Tables 14-17. As is clear from Tables 14 to 17, the products of the present invention all have a better appearance than the comparative products, have no precipitates, have a small increase in the acid value, and have a thermal stability in the presence of water. It was good.

[0146]

[Table 14]

[0147]

[Table 15]

[0148]

[Table 16]

[0149]

[Table 17]

Example 6 A test oil was prepared by mixing 1 part by weight of contamination with 100 parts by weight of the lubricating oil composition of the present invention, and HFC13
4a / test oil was mixed at a 95/5 weight ratio and sealed in a pressure-resistant glass container. The temperature at which the contaminants were uniformly dissolved was visually determined in the range from 0 ° C to 60 ° C. Moreover, it carried out similarly using the comparative product. Table 1 shows the results.
8 shows. The following three types of contaminants were used. Contamination c is a hot tube tester (HT-2
01) is used to set the contamination a at an air flow rate of 8 ml / min,
It was deteriorated at a temperature of 270 ° C.

Contamination a: Ester-based metal working oil (manufactured by Kyoei Yuka Co., Ltd.) 40 ° C. kinematic viscosity 300 mm ² / s Contamination b: Mineral oil-based metal working oil (manufactured by Idemitsu Kosan Co., Ltd.) 40 ° C. kinematic viscosity 20 mm ² / s Contamination c: Degraded product of ester metal working oil a

[0152]

[Table 18]

From the results shown in Table 18, it was found that the product of the present invention had a lower contamination melting temperature than the comparative product and was excellent in the contamination dissolving power.

Example 7 210 g of test oil mixed with 5 parts by weight of contamination to 100 parts by weight of the lubricating oil composition of the present invention, and 1,1,1,1,
70 g of 2-tetrafluoroethane (HFC134a)
It was enclosed in a 200 W reciprocating compressor equipped with a capillary. The compressor was continuously operated for 200 hours at an upper temperature of 110 ° C., and the contamination of the capillaries was visually determined. Moreover, it carried out similarly using the comparative product. Table 19 shows the results.

[0155]

[Table 19]

From the results shown in Table 19, it was found that the product of the present invention had less capillary fouling than the comparative product and was superior in the ability to dissolve contaminants.

Example 8 310 g of test oil mixed with 100 parts by weight of the lubricating oil composition of the present invention at a ratio of 5 parts by weight of contamination, and 1,1,1,
2-Tetrafluoroethane (HFC134a) 100g
Was sealed in a 150 W reciprocating compressor equipped with a capillary. The compressor was continuously operated for 200 hours at an upper temperature of 110 ° C., and the contamination of the capillaries was visually determined. Moreover, it carried out similarly using the comparative product. Table 20 shows the results.

[0158]

[Table 20]

From the results shown in Table 20, it was found that the product of the present invention had less capillary fouling than the comparative product and was superior in the ability to dissolve contaminants.

Example 9 370 g of test oil mixed with 100 parts by weight of the lubricating oil composition of the present invention at a ratio of 5 parts by weight of contamination, and 1,1,1,1
2-Tetrafluoroethane (HFC134a) / Difluoromethane (HFC32) / Pentafluoromethane (HF
C125) = 52/23/23 (weight ratio) 380 g,
It was enclosed in a 1 KW rotary compressor equipped with a capillary. The compressor was continuously operated for 200 hours at an upper temperature of 110 ° C., and the contamination of the capillaries was visually determined. Moreover, it carried out similarly using the comparative product. Table 21 shows the results.

[0161]

[Table 21]

From the results shown in Table 21, it was found that the product of the present invention had less capillary fouling than the comparative product and was superior in the ability to dissolve contaminants.

[0163]

EFFECTS OF THE INVENTION According to the present invention, excellent thermal stability and acid value stability, no generation of carboxylic acid due to hydrolysis, low hygroscopicity, excellent viscosity index, low cost, and good solubility for contamination can be obtained. A high lubricating oil composition is provided. In addition, the composition for refrigerator working fluid is excellent in compatibility with hydrofluorocarbon, electric insulation, hygroscopicity, viscosity index, etc., does not generate carboxylic acid due to hydrolysis, etc., is inexpensive, and has a high solubility for contamination. Will be provided.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location C10N 20:02 30:00 30:08 40:30 70:00 (72) Inventor Yoshiaki Oshima 1334 Minato Minato Wakayama City Address: Kao Corporation Research Laboratory (72) Koji Hira, 1334 Minato Minato, Wakayama City Kao Research Institute

Claims (13)

[Claims] 1. A kinematic viscosity at 100 ° C. of 0.1 to 10
A lubricating oil composition comprising a polyalkylene glycol compound of 0 mm ² / s and a cyclic ketal or a cyclic acetal. 2. A cyclic ketal or cyclic acetal, and one or more polyhydric alcohols having an even valence of 4 or more and 10 or less, and a general formula (1): (In the formula, R ¹ is a hydrogen atom or a straight chain having 1 to 18 carbon atoms,
It represents a branched or cyclic alkyl group, and R ² represents a straight chain, branched chain, or cyclic alkyl group having 1 to 18 carbon atoms. Alternatively, R ¹ and R ² together have 2 carbon atoms
~ 36 alkylene groups are shown. The lubricating oil composition according to claim 1, which is obtained from at least one of a carbonyl compound represented by the formula (1) or a reactive derivative thereof, a ketal or an acetal. 3. The cyclic ketal or cyclic acetal is one or more polyhydric alcohol having an even valence of 4 to 8 and a general formula (2) (In the formula, R ³ is a hydrogen atom or a straight chain having 1 to 12 carbon atoms,
A branched or cyclic alkyl group is shown, and R ⁴ is a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms. Alternatively, R ³ and R ⁴ together have 2 carbon atoms
~ 13 alkylene groups are shown. The total carbon number of R ³ and R ⁴ is 1 to 13. The lubricating oil composition according to claim 1, which is obtained from at least one of a carbonyl compound represented by the formula (1) or a reactive derivative thereof, a ketal or an acetal. 4. The lubricating oil composition according to claim 2 or 3, wherein the polyhydric alcohol has no ether bond or has one ether bond. 5. The cyclic ketal or cyclic acetal is
The lubricating oil composition according to any one of claims 1 to 4, which comprises a 1,3-dioxolane structure and / or a 1,3-dioxane structure. 6. A ketal or a cyclic ketal or a cyclic acetal which is a tetravalent or hexavalent saturated aliphatic alcohol having 4 to 20 carbon atoms and a carbonyl compound represented by the general formula (2) or a reactive derivative thereof. It is obtained from one or more kinds of acetals.
The lubricating oil composition described. 7. The cyclic ketal or cyclic acetal is represented by the general formula (3) or (4): (In the formula, R ³ is a hydrogen atom or a straight chain having 1 to 12 carbon atoms,
A branched or cyclic alkyl group is shown, and R ⁴ is a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms. Alternatively, R ³ and R ⁴ together have 2 carbon atoms
~ 13 alkylene groups are shown. The total carbon number of R ³ and R ⁴ is 1 to 13. ) The lubricating oil composition according to claim 1, which is represented by 8. A cyclic ketal or cyclic acetal is represented by the general formula (5) or (6): (In the formula, R ³ is a hydrogen atom or a straight chain having 1 to 12 carbon atoms,
A branched or cyclic alkyl group is shown, and R ⁴ is a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms. Alternatively, R ³ and R ⁴ together have 2 carbon atoms
~ 13 alkylene groups are shown. The total carbon number of R ³ and R ⁴ is 1 to 13. ) The lubricating oil composition according to claim 1, which is represented by 9. The mixing ratio of the polyalkylene glycol compound and the cyclic ketal or cyclic acetal in the lubricating oil composition is polyalkylene glycol compound / cyclic ketal, cyclic acetal = 1/99 to 99/1 (weight ratio). Item 9. A lubricating oil composition according to any one of items 1 to 8. 10. The polyalkylene glycol compound is
A compound represented by the following general formula (7):
9. The lubricating oil composition according to any one of 9 above. ^{A- (O- (R 5 O)} v-R 6) w (7) ( wherein, R ⁵ is .R ⁶ is hydrogen atom represents a linear or branched chain alkylene group having 2 to 4 carbon atoms, carbon atoms It represents a hydrocarbon group having 1 to 18 or an acyl group having 2 to 18 carbon atoms, A is a hydrogen atom, a w-valent alcohol residue having 1 to 18 carbon atoms, or a w-valent phenol residue having 6 to 18 carbon atoms. Represents a group, and v is 1 to
The number of 50 and w represent the number of 1 to 6. However, v R ⁵
O, w R ⁶ and w O— (R ⁵ O) v—R ⁶ may be the same or different. ) 11. A polyalkylene glycol compound,
A compound represented by the following general formula (8):
9. The lubricating oil composition according to any one of 9 above. R < ⁷ > O- (R < ⁵ > O) x-R <^8> (8) (In formula, R < ⁵ > represents a C2-C4 linear or branched alkylene group. R < ⁷ > is a C1-C18 hydrocarbon. Represents a group, R ⁸ represents a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, x represents a number of 1 to 50. However, R ⁷ and R ⁸ may be the same or different. Also, x R ⁵
O may be the same or different. ) 12. A refrigerating machine working fluid composition comprising a refrigerating machine oil containing the lubricating oil composition according to any one of claims 1 to 11 and hydrofluorocarbon. 13. Hydrofluorocarbon and refrigerating machine oil, wherein hydrofluorocarbon / refrigerating machine oil = 50/1.
The composition for a working fluid of a refrigerator according to claim 12, which is contained in an amount of ˜1 / 20 (weight ratio).