JPH11256182A - Lubricant composition for refrigerator using hfc-32 - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an oil for a refrigerator using HFC-32 as a refrigerant, excellent in corrosion-resistance of the interior of a compressor and cleanliness in the compressor, especially capable of keeping the cleanliness for a long term in the interior of the compressor, and capable of providing a high reliability. SOLUTION: This lubricant composition for a refrigerator using an HFC- based refrigerant containing HFC-32 is obtained by using an ester composed of a di or more polyhydric alcohol as an alcoholic component and a monobasic fatty acid singly or as a mixture as a base oil, and blending additives comprising (1) 0.01-1.0% esters of orthophosphoric acid, (2) 0.01-1.0% alkylphosphorothionates and/or arylphosphorothionates, and (3) 0.01-1.0% epoxy compounds, with the base oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a refrigerating machine oil and a refrigerating machine working fluid composition, and more particularly, to HFC-3 using an ester having a specific structure alone or in a mixture of multiple kinds.
The present invention relates to a lubricating oil composition for a refrigerator using an HFC-based refrigerant containing 2.

[0002]

2. Description of the Related Art Due to the problem of depletion of the ozone layer in recent years, CFC (chlorofluorocarbon) and HCFC (hydrochlorofluorocarbon), which have been conventionally used as refrigerants for refrigeration equipment, have been subject to regulation.
C (hydrofluorocarbon) is being used as a refrigerant. As the refrigerating machine oil for the HFC refrigerant, PAG (polyalkylene glycol), ester, and the like, which are compatible with HFC, have been studied or used. For example, PAG is described in U.S. Pat. No. 4,755,316,
No. 98694, Japanese Patent Application Laid-Open No. 1-256594, Japanese Patent Application Laid-Open No. 1-259093, Japanese Patent Application Laid-Open No. 1-259994
JP, JP-A 1-259095, JP-A 1-2
74191, JP-A-2-43290, JP-A-2-55791, JP-A-2-84491 and the like.
505602, JP-A-3-55791, JP-A-3-88892, JP-A-2-128991, JP-A-2-128992, JP-A-3-20
No. 0895, JP-A-3-22797, JP-A-4-20597, JP-A-4-72390, JP-A-4-218592, JP-A-4-218
No. 593, etc. However, PAG
Has the disadvantage of high hygroscopicity and poor electrical insulation. On the other hand, ester oils may hydrolyze due to their structure and generate acids, and the generated acids are expected to cause various disadvantages in the refrigerator system. Further, since these oils are inferior in lubricity as compared with conventional mineral oil and CFC / HCFC or mineral oil, alkylbenzene and CFC / HCFC, blending of various additives has been studied. Further, the refrigerating machine oil is strongly affected by the high-temperature and high-pressure atmosphere of the refrigerant compressor, and dirt resulting from thermal decomposition of the refrigerating machine oil adheres to the inside of the compressor, which is a new problem. The present inventors have intensively studied the improvement of the cleanliness in the compressor, and as a result, by adding a specific amount of a specific additive to a specific ester, the cleanliness of various types of compressors is improved. This led to the completion of the present invention.

[0003]

SUMMARY OF THE INVENTION The present invention relates to HFC-3
The object of the present invention is to provide a refrigerating machine oil that uses 2 as a refrigerant, has excellent corrosion inside the compressor and cleanliness inside the compressor, and particularly maintains the cleanliness inside the compressor for a long period of time and obtains high reliability. I do.

[0004]

The object of the present invention is to provide an H
A lubricating oil composition for a refrigerator using an HFC-based refrigerant containing FC-32, wherein an ester comprising a polyhydric all or more monovalent fatty acid and a monovalent fatty acid on the alcohol side is used alone or in combination as a base oil. In addition, the additive may contain 1) orthophosphoric acid esters in an amount of 0.01 to less than 1.0% and 2) alkylphosphorothionates and / or arylphosphorothionates in an amount of 0.01 to 1.0% or less. , And 3) a lubricating oil composition for a refrigerator comprising 0.01 to 1.0% or less of an epoxy compound.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The contents of the present invention will be described below in detail.
As the base oil of the refrigerating machine oil composition of the present invention, any synthetic ester comprising a dihydric or higher alcohol and a monohydric fatty acid may be used as the ester, but neopentyl glycol, trimethylolpropane, pentaerythritol and dipentane are preferred. Erythritol, more preferably trimethylolpropane and pentaerythritol. The monovalent fatty acids include propionic acid, isopropionic acid, butanoic acid, isobutanoic acid, pentanoic acid, isopentanoic acid, hexanoic acid, heptanoic acid, isopentanoic acid, octanoic acid, isooctanoic acid, 2-ethylhexanoic acid, nonanoic acid, isononane Acid, 3,5,5-trimethylhexanoic acid, decanoic acid, undecanoic acid, lauric acid and the like. These monovalent fatty acids may be used alone or as a mixture of two or more kinds in the esterification reaction. Furthermore, the mixing ratio of these can be changed at an arbitrary ratio according to the refrigeration equipment. However, these are used only as base oils, and their mixing does not improve the cleanability of the compressor. Therefore, compressor cleanliness is improved by adding 1) orthophosphoric esters, 2) arylphosphorothionates and / or alkylphosphorothionates, and 3) epoxy compounds to these mixed base oils. be able to. Here, the orthophosphates as the component 1) include, for example, tributyl phosphate, trihexyl phosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, trioleyl phosphate, triphenyl phosphate. , Tricresyl phosphate, phenyl, isopropylphenyl phosphate, tris (isopropylphenyl) phosphate and the like. In particular, phenyl, isopropylphenyl phosphate, tris (isopropylphenyl) phosphate and tricresyl phosphate are preferred. The arylphosphorothionate and / or alkylphosphorothionate as the component 2) includes trihexyl phosphorothionate, triphenyl phosphorothionate, and tris (methylphenyl).
Phosphorothionate and tris (isobutylphenyl) phosphorothionate. Of these, triphenylphosphorothionate is particularly preferred. Further, as the epoxy compound, 1,2-epoxyhexane, 1,2-epoxyheptane, 1,2-epoxyoctane, 1,2-epoxydecane, 1,2-epoxyhdecane, 1,2-epoxidedodecane, 1,2-epoxytetradecane, 1,2-epoxyhexadecane,
Examples of 1,2-epoxyheptadecane and 1,2-epoxyoctadecane and alicyclic epoxy compounds include vinylcyclohexene dioxide. These can be used alone or in combination, but it is particularly preferable to use 1,2-epoxydecane and vinylcyclohexene dioxide alone or in combination.

The refrigerating machine oil composition of the present invention contains known antioxidants, metal deactivators, defoamers and other additives in the refrigerating machine oil within a range of improving the cleanliness aimed at by the present invention. Can be used.

The antioxidants include, for example, hindered phenol-based, amine-based and sulfur-based antioxidants such as 2,6-di-t-butyl-4-methylphenol,
4'-meletin bis (2,6-di-butylphenol), 2,2'-thiobis (4-methyl-6-t-butylphenol), p, p'-dioctyldiphenylamine, 3,7-dioctylphenothiazine, phenyl-α
-Naphthylamine, alkyl disulfide and the like can be used.

As the metal deactivator, for example, alizanin, quinizarin, benzotriazole and the like can be used.

As an antifoaming agent, for example, dimethylpolysiloxane, metal carboxylate and the like can be used. These additives can be used alone or in combination of two or more. The amounts of these antioxidants, metal deactivators, and antifoaming additives are 10% or less, preferably 5% or less, based on the base oil.

As the refrigerant used in the refrigerator using the refrigerator oil of the present invention, HFC-32 alone or a mixture of fluorinated alkanes having 1 to 3 carbon atoms, preferably 1 to 2 carbon atoms, can be used. However, as the mixed solvent, difluoromethane (HFC-32) is 20% by weight or more and HF
C-134a is less than 50% by weight, and HFC-125
Is less than 30% by weight. This HFC-32
When used as a mixture, the content is preferably 30% by weight or more, more preferably 40% by weight or more. H
The HFC-based refrigerant that can be mixed with the FC-32 is not particularly limited. Specifically, for example, trifluoromethane (HFC-23), pentafluoroethane (HFC-
125), 1,1,2,2-tetrafluoroethane (H
HFC such as FC-134), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a) Is mentioned.

The refrigerating machine oil composition according to the present invention is usually mixed with the above-mentioned refrigerant in a refrigerating machine, and the proportion thereof is also optional depending on the model. The refrigerating machine oil composition of the present invention is preferably used for an air conditioner or a refrigerator having a reciprocating type or a rotary hermetic compressor such as a scroll or a rotary in view of its excellent compressor cleanliness. Further, it is used for dehumidifiers, freezers, freezers, refrigerated warehouses, vending machines, showcases, chemical plants, and the like. Further, it is preferably used for those having a centrifugal compressor.

[0012]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited to these Examples. The ester used in the experiment was pentaerythritol as the alcohol,
Using a mixture of isooctanoic acid and isononanoic acid as the acid, 56.2 mm ² / s @ 40 ° C., total acid value 0.01 mg
KOH / g was used. As additives, tricresyl phosphate was used as antiwear agent I, triphenylphosphorothionate as antiwear agent II, and 1,2-epoxydecene as epoxy compound. Tables 1 to 6 show the compositions and experimental results of the refrigerator oil compositions used in the present invention and comparative examples. [Evaluation Test 1] Using a rotary compressor and a scroll compressor, 500 ml of sample oil and a refrigerant (HFC-32)
Filled with 1000 g, the discharge pressure of 20kg ^/ cm 2 ~30k
g / cm ² , discharge temperature 70 to 140 ° C, test oil temperature 10
Continuous operation was performed at 0 to 160 ° C. for 2000 hours, and the cleanliness in the compressor was evaluated. Here, cleanliness refers to the degree of dirt or discoloration in the compressor. The evaluation is based on the knowledge obtained so far based on the current product (alkylbenzene / R-2
2) is given a score of 10, and a score of less than 10 is considered a pass.
Is the best.

As shown in the evaluation results in the table, in the range of the examples, the cleanliness was less than 10 and it was found that the cleanliness was good. On the other hand, Comparative Examples 1 to 7 are results of evaluation using a scroll compressor. Comparative Example 1 is a single base oil, and it can be seen that base oil has poor cleanability.

In Comparative Examples 2 to 4, each of the additives was added as a single substance.

In Comparative Examples 5 to 7, two kinds of additives are blended.

Comparative Examples 2 to 21 are the results obtained by using a rotary compressor. Comparative Example 8 is a single base oil, and shows that base oil has poor cleanability and is inferior to a scroll compressor.

In Comparative Examples 9 to 11, the additives were added alone, but the cleanliness was poor when used alone.

In Comparative Examples 12 to 14, two kinds of additives among three kinds of additives are combined, and it can be seen that the cleaning effect is inferior even within the claims.

In Comparative Examples 15 to 19, all additives were blended. In Comparative Example 15, the antiwear agent I was beyond the scope of the claims, and in this case, the detergency was poor.

In Comparative Example 16, the antiwear agent II was beyond the claimed range, and this was also inferior in cleanability.

In Comparative Example 17, the heat stabilizer was beyond the claimed range, and this was also inferior in cleanability.

In Comparative Example 18, antiwear agent I and antiwear agent I were used.
I exceeds the scope of the claims, which is also inferior in cleanliness.

In Comparative Example 19, the amount of the antiwear agent II and the epoxy compound exceeded the claimed range, and this was also inferior in cleanability.

In Comparative Example 20, the amount of the antiwear agent I and the epoxy compound exceeded the scope of the claims, and this also had poor cleanability.

In Comparative Example 21, all of the additives were outside the scope of the claims, and this was also inferior in cleanability.

In Comparative Example 22, all the additives were below the claimed range, and this was also inferior in cleanability.

Comparative Example 23 shows that R-2
This is the case where 2 is used as a refrigerant, but this combination is also inferior in cleanliness.

Comparative Example 24 is the current combination (alkylbenzene / R-22).

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

[0033]

[Table 5]

[0034]

[Table 6]

[0035]

According to the present invention, HFC-32 is used as a refrigerant, and is excellent in corrosion inside the compressor and cleanliness inside the compressor. It is possible to provide a refrigerating machine oil having good properties.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C10N 40:30 (72) Inventor Tomohiro Magome 1-1-17-201, Kodai, Miyama-ku, Kawasaki-shi, Kanagawa-ken (72) Invention Yasuyuki Akahori 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Takeshi Izawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Noboru Masuda 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (1)

[Claims] 1. A lubricating oil composition for a refrigerator using an HFC-based refrigerant containing HFC-32, wherein an ester comprising a polyhydric all or more monovalent fatty acid and a monovalent fatty acid on the alcohol side is used alone or in combination. 1) orthophosphoric esters 0.01 to less than 1.0%, 2)
Lubricating oil for refrigerators containing 0.01 to 1.0% or less of alkylphosphorothionate and / or arylphosphorothionate, and 3) 0.01 to 1.0% of epoxy compound. Composition.