TWI540205B - The refrigerating machine oil and the refrigerator are used as the hydrothermal composition - Google Patents

Description

Refrigeration oil and freezer used as dynamic fluid composition

The present invention relates to a refrigerating machine oil and a refrigerating machine for use as a dynamic fluid composition, and more particularly to a refrigerating machine oil for use in combination with a difluoromethane refrigerant (HFC-32), an unsaturated fluorinated hydrocarbon or the like. And a refrigerator using the refrigerator oil is used as the dynamic fluid composition.

Due to the problem of ozone layer destruction in recent years, CFC (Chlorofluorocarbon) and HCFC (Hydrochlorofluorocarbon), which have been used as refrigerants for refrigerating machines, have become the subject of restrictions and are using HFC (Fluorohydrocarbon, hydrogen). The fluorocarbon) replaces these as a refrigerant.

When CFC or HCFC is used as the refrigerant, a hydrocarbon oil such as mineral oil or alkylbenzene can be preferably used as the refrigerating machine oil. However, if the refrigerant is changed, the refrigerating machine oil used in the coexistence will be in the phase with the refrigerant. The solubility, the lubricity, the solubility of the refrigerant, and the thermo-chemical stability are unpredictable. Therefore, it is necessary to develop the refrigerating machine oil for each type of refrigerant. For example, as a refrigerant oil for HFC refrigerant, for example, a polyalkylene glycol (refer to Japanese Laid-Open Patent Publication No. Hei 02-242888), an ester (refer to Japanese Patent Laid-Open No. Hei 03-200895), and a carbonate (see Japanese Patent) Japanese Laid-Open Patent Publication No. Hei 03-217495, and a polyvinyl ether (refer to Japanese Laid-Open Patent Publication No. Hei 06-128578). Among these refrigerating machine oils, esters are widely used as refrigerators, air conditioners, and the like.

HFC-134a, R407C, R410A can be used standardly in HFC refrigerant Used as a refrigerant for automotive air conditioning, refrigerators or indoor air conditioners. However, these HFC refrigerants are becoming targets because the ozone depletion potential (ODP) is 0, but the global warming potential (GWP) is high. Therefore, it has become a top priority to develop a refrigerant that replaces these HFCs.

Under such a background, it is proposed to use a fluoropropylene-based refrigerant having a thermodynamic property as a standard of refrigerant performance and having substantially the same thermodynamic properties as the above-mentioned HFC as a refrigerant for replacing the above HFC, which is very small and incombustible. Further, a mixed refrigerant using fluoropropene and a saturated hydrofluorocarbon, a saturated hydrocarbon having a carbon number of 3 to 5, dimethyl ether, carbon dioxide, bis(trifluoromethyl) sulfide or trifluoroiodomethane is also proposed (refer to International Publication WO 2006/094303 manual). Moreover, the difluoromethane refrigerant (HFC-32) has attracted attention due to its relatively low global warming coefficient and high refrigeration efficiency in HFC refrigerants.

However, as one of the properties of the refrigerating machine oil, there is compatibility with the refrigerant to be used in combination. Therefore, it is being developed for use in a refrigerating machine oil suitable for such a refrigerant when a difluoromethane refrigerant or an unsaturated fluorinated hydrocarbon refrigerant is used.

For example, in general, since the refrigerating machine oil that lubricates the refrigerant compressor circulates in the circulation ring together with the refrigerant, the refrigerant oil is required to be compatible with the refrigerant. However, if the refrigerating machine oil and the difluoromethane refrigerant previously used as the HFC refrigerant are used together, the refrigerant and the refrigerating machine oil are not sufficiently compatible, and the refrigerating machine oil discharged from the refrigerant compressor is likely to remain in the circulation ring. As a result, there is a problem in that the amount of the refrigerator oil in the refrigerant compressor is lowered to cause poor lubrication or to block an expansion mechanism such as a capillary. Therefore, in order to avoid this phenomenon, the development of refrigeration oil for difluoromethane refrigerant is being promoted. For example, Japanese Laid-Open Patent Publication No. Hei. No. Hei. The ester-based refrigerating machine oil disclosed in Japanese Laid-Open Patent Publication No. 2002-129177, Japanese Patent Laid-Open No. Hei No. 2002-129178, and JP-A-2002-129179.

However, even in the case where the above-mentioned ester-based refrigerating machine oil is used together with a difluoromethane refrigerant or an unsaturated fluorinated hydrocarbon, it is not always sufficient performance. In particular, when the conventional ester-based refrigerating machine oil is used together with the difluoromethane refrigerant, it is difficult to cope with the compatibility with the difluoromethane refrigerant and the viscosity necessary for the refrigerating machine oil. For example, in the conventional ester-based refrigerating machine oil, the compatibility with the difluoromethane refrigerant tends to be insufficient in the presence of the difluoromethane refrigerant.

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a refrigerant which can be used for compatibility with a refrigerant, a lubricating property, and a low temperature when used together with a difluoromethane refrigerant or an unsaturated fluorinated hydrocarbon. The refrigerating machine oil which is all achieved at a high level, and the refrigerating machine using the same are used as the dynamic fluid composition.

In order to solve the above problems, the present invention provides a refrigerating machine oil comprising an ester of a polyhydric alcohol and a fatty acid, wherein the fatty acid having a carbon number of 4 to 6 and a molar ratio of a branched fatty acid having a carbon number of 7 to 9 For 15:85~90:10, the above-mentioned fatty acids having a carbon number of 4-6 contain 2-methylpropionic acid, and the total of the fatty acids having a carbon number of 4-6 and the branched fatty acids having a carbon number of 7-9 The ratio of the total amount of the fatty acids constituting the above ester is 20 mol% or more.

In the refrigerating machine oil of the present invention, the ratio of the 2-methylpropionic acid to the fatty acid having 4 to 6 carbon atoms is preferably 20 mol% or more.

Further, in the refrigerator oil of the present invention, it is preferred that the fatty acid having 4 to 6 carbon atoms is 2-methylpropionic acid.

In the refrigerating machine oil of the present invention, it is preferred that the polyhydric alcohol is pentaerythritol, and the dynamic viscosity of the refrigerating machine oil at 40 ° C is 20 to 80 mm ² /s.

Further, in the refrigerator oil of the present invention, it is preferable that the branched fatty acid having 7 to 9 carbon atoms is 3,5,5-trimethylhexanoic acid.

Further, the present invention provides a refrigerating machine for use as a dynamic fluid composition comprising the above-described refrigerating machine oil of the present invention and a difluoromethane refrigerant.

Further, the present invention provides a refrigerating machine for use as a dynamic fluid composition comprising the above-described refrigerating machine oil of the present invention and an unsaturated fluorinated hydrocarbon refrigerant.

Further, the present invention provides a refrigerating machine for use as a dynamic fluid composition comprising the above-described refrigerating machine oil, difluoromethane refrigerant and unsaturated fluorinated hydrocarbon refrigerant of the present invention. Here, the quality of the difluoromethane refrigerant and the unsaturated fluorinated hydrocarbon refrigerant is preferably 95:5 to 50:50.

As described above, according to the present invention, there is provided a refrigerating machine oil which can achieve a high level of refrigerant compatibility, lubricity and low-temperature fluidity when used together with a difluoromethane refrigerant or an unsaturated fluorinated hydrocarbon or the like. And a refrigerator using the same as a dynamic fluid composition.

Hereinafter, preferred embodiments of the present invention will be described in detail.

The refrigerator oil of the present embodiment contains an ester of a polyhydric alcohol and a fatty acid, and the ester (hereinafter referred to as "polyol fatty acid ester (A)") contains a fatty acid having 4 to 6 carbon atoms in the fatty acid. The molar ratio of branched fatty acids with a carbon number of 7 to 9 is 15:85 to 90:10, and the fatty acids having a carbon number of 4 to 6 contain 2-methylpropionic acid, and the fatty acids having a carbon number of 4 to 6 and carbon number The ratio of the total of the branched fatty acids of 7 to 9 to the total amount of the fatty acids constituting the above ester is 20 mol% or more.

Further, the polyol fatty acid ester (A) includes a complete ester obtained by esterifying all the hydroxyl groups of the polyol, a partial ester in which a part of the hydroxyl group of the polyol is not esterified, and a partial ester and a partial ester. The hydroxyl value of the polyol fatty acid ester (A) is preferably 10 mgKOH/g or less, more preferably 5 mgKOH/g or less, and most preferably 3 mgKOH/g or less.

In the fatty acid constituting the polyol fatty acid ester (A), the molar ratio of the fatty acid having 4 to 6 carbon atoms to the fatty acid having a branched carbon number of 7 to 9 is 15:85 to 90:10, preferably 15:85~85:15, more preferably 20:80~80:20, and further preferably 25:75~75:25, and most preferably 30:70~70:30. Further, the total of the fatty acids having a carbon number of 4 to 6 and the fatty acids having a branched carbon number of 7 to 9 in the total amount of the fatty acid constituting the polyhydric alcohol fatty acid ester (A) is 20 mol% or more. When the above conditions regarding the fatty acid composition are not satisfied, it becomes difficult to coexist with a sufficient compatibility with the difluoromethane refrigerant and a viscosity necessary as a refrigerating machine oil. Further, the ratio of the fatty acid in the present invention means a value based on the total amount of the fatty acid constituting the polyol fatty acid ester contained in the refrigerator oil.

Specific examples of the fatty acid having 4 to 6 carbon atoms include, for example, Acid, 2-methylpropionic acid, valeric acid, 2-methylbutyric acid, 3-methylbutyric acid, 2,2-dimethylpropionic acid, 2-methylpentanoic acid, 3-methylpentanoic acid, 4-methylpentanoic acid, 2,2-dimethylbutyric acid, 2,3-dimethylbutyric acid, 3,3-dimethylbutyric acid, caproic acid, and the like. Among these, it is preferred to have a branch on the alkyl skeleton like 2-methylpropionic acid.

Examples of the fatty acid having a branched carbon number of 7 to 9 include, for example, 2-methylhexanoic acid, 3-methylhexanoic acid, 4-methylhexanoic acid, 5-methylhexanoic acid, and 2, 2-dimethylvaleric acid, 2,3-dimethylvaleric acid, 2,4-dimethylvaleric acid, 3,3-dimethylvaleric acid, 3,4-dimethylvaleric acid, 4, 4-Dimethylpentanoic acid, 2-ethylpentanoic acid, 3-ethylpentanoic acid, 1,1,2-trimethylbutyric acid, 1,2,2-trimethylbutyric acid, 1-ethyl -1-methylbutyric acid, 1-ethyl-2-methylbutyric acid, octanoic acid, 2-ethylhexanoic acid, 3-ethylhexanoic acid, 3,5-dimethylhexanoic acid, 2,4- Dimethylhexanoic acid, 3,4-dimethylhexanoic acid, 4,5-dimethylhexanoic acid, 2,2-dimethylhexanoic acid, 2-methylheptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, 5-methylheptanoic acid, 6-methylheptanoic acid, 2-propylpentanoic acid, citric acid, 2,2-dimethylheptanoic acid, 2-methyloctanoic acid, 2-B Heptanoic acid, 3-methyloctanoic acid, 3,5,5-trimethylhexanoic acid, 2-ethyl-2,3,3-trimethylbutyric acid, 2,2,4,4-tetramethyl Valeric acid, 2,2,3,3-tetramethylpentanoic acid, 2,2,3,4-tetramethylpentanoic acid, 2,2-diisopropylpropionic acid, and the like.

In the polyol fatty acid ester (A), the molar ratio of the fatty acid having 4 to 6 carbon atoms to the fatty acid having a branched carbon number of 7 to 9 is 15:85 to 90:10, and as long as the carbon number is 4~ When the fatty acid of 6 contains 2-methylpropionic acid, a fatty acid having a carbon number of 4 to 6 and a fatty acid having a branched carbon number of 7 to 9 may be contained as a constituent acid component.

As a fatty acid having 4 to 6 carbon atoms and having a branched carbon number of 7 to 9 Specific examples of the fatty acid other than the acid include a fatty acid having a carbon number of 2 to 3 such as acetic acid or propionic acid, a linear fatty acid having a carbon number of 7 to 9 such as heptanoic acid, caprylic acid or citric acid, and citric acid or undecanoic acid. , fatty acids such as dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, octadecanoic acid, nonadecyl acid, icosonic acid, oleic acid and the like having a carbon number of 10-20.

When a fatty acid having 4 to 6 carbon atoms and a fatty acid having a branched carbon number of 7 to 9 are used in combination with a fatty acid other than the fatty acid, the fatty acid having 4 to 6 carbon atoms and the carbon number is 7 to 9 The ratio of the total amount of the branched fatty acids to the total amount of the fatty acids constituting the polyol fatty acid ester (A) must be 20 mol% or more, preferably 25 mol% or more, more preferably 30 mol% or more. By the ratio of 20 mol% or more, the compatibility with the difluoromethane refrigerant becomes sufficient.

In the polyol fatty acid ester (A), the acid component contains only 2-methylpropionic acid and 3,5,5-trimethylhexanoic acid to ensure the necessary viscosity and compatibility with the difluoromethane refrigerant. It is especially good for coexistence.

The polyol fatty acid ester of the present embodiment may be a mixture of two or more kinds of esters having different molecular structures. In this case, each molecule does not necessarily need to satisfy the above conditions as long as it constitutes a pentaerythritol fatty acid ester contained in the refrigerator oil. The fatty acid as a whole can satisfy the above conditions.

As described above, the polyol fatty acid ester (A) has a fatty acid having 4 to 6 carbon atoms and a fatty acid having a branched carbon number of 7 to 9 as an acid component constituting the ester, and optionally contains other fatty acid as a constituent component. In other words, the polyhydric alcohol fatty acid ester (A) may have only two kinds of fatty acids as an acid constituent component, or three or more kinds of fatty acids having different structures may be used as an acid constituent component. However, the polyhydric alcohol fatty acid ester preferably contains only The carbon atom adjacent to the carbonyl carbon (the alpha carbon atom) is not It is a four-stage carbon fatty acid as an acid constituent. In the case where the fatty acid constituting the polyol fatty acid ester contains a fatty acid having a carbon atom at the α-position as a quaternary carbon, the lubricity in the presence of the difluoromethane refrigerant tends to be insufficient.

Further, as the polyol constituting the polyol ester of the present embodiment, a polyol having 2 to 6 hydroxyl groups can be preferably used.

Specific examples of the diol (diol) include ethylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,2-butanediol, and 2-methyl-1. , 3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,8-octanediol, 1,9-nonanediol, 1,10- Decylene glycol, 1,11-undecanediol, 1,12-dodecanediol, and the like. Further, examples of the trivalent or higher alcohol include trimethylolethane, trimethylolpropane, trimethylolbutane, di-(trimethylolpropane), and tri-(three). Hydroxymethylpropane), pentaerythritol, bis-(pentaerythritol), tris-(pentaerythritol), glycerin, polyglycerol (2~3mer of glycerol), 1,3,5-pentanetriol, sorbitol, dehydrated sorbet Alcohol, sorbitol glycerol condensate, sagel, arabitol, xylitol, mannitol and other polyols, xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbus Sugars such as sugar and cellobiose, and some of these etherates. Among these, in terms of more excellent hydrolytic stability, it is more preferably neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, or di-(trishydroxyl). An ester of a hindered alcohol such as methyl propane), tris-(trimethylolpropane), pentaerythritol, di-(pentaerythritol) or tris-(pentaerythritol), and more preferably neopentyl glycol or trimethylolethane. Trimethylolpropane, trimethylolbutane and An ester of pentaerythritol or di-(pentaerythritol), more preferably neopentyl glycol, trimethylolpropane, pentaerythritol or di-(pentaerythritol), is particularly excellent in compatibility with a refrigerant and hydrolytic stability. Most preferred is pentaerythritol, bis-(pentaerythritol) or a mixed ester of pentaerythritol and bis-(pentaerythritol).

Preferred examples of the acid constituent component constituting the polyol fatty acid ester (A) of the present invention include the following.

(i) selected from the group consisting of butyric acid, 2-methylpropionic acid, valeric acid, 2-methylbutyric acid, 3-methylbutyric acid, 2,2-dimethylpropionic acid, 2-methylpentanoic acid, 3 -1 to 13 of methylvaleric acid, 4-methylpentanoic acid, 2,2-dimethylbutyric acid, 2,3-dimethylbutyric acid, 3,3-dimethylbutyric acid and caproic acid And selected from the group consisting of 2-methylhexanoic acid, 3-methylhexanoic acid, 4-methylhexanoic acid, 5-methylhexanoic acid, 2,2-dimethylvaleric acid, 2,3-dimethyl Valeric acid, 2,4-dimethylvaleric acid, 3,3-dimethylvaleric acid, 3,4-dimethylvaleric acid, 4,4-dimethylvaleric acid, 2-ethylpentanoic acid, a combination of 1 to 13 of 3-ethylvaleric acid and 2-ethyl-3-methylbutyric acid; (ii) selected from butyric acid, 2-methylpropionic acid, valeric acid, 2-methylbutyl Acid, 3-methylbutyric acid, 2,2-dimethylpropionic acid, 2-methylpentanoic acid, 3-methylpentanoic acid, 4-methylpentanoic acid, 2,2-dimethylbutyric acid, 1 to 13 of 2,3-dimethylbutyric acid, 3,3-dimethylbutyric acid and hexanoic acid, and selected from 2-methylheptanoic acid, 3-methylheptanoic acid, 4-methyl Heptanoic acid, 5-methylheptanoic acid, 6-methylheptanoic acid, 2,2-dimethylhexanoic acid, 3,3-dimethylhexanoic acid, 4,4-dimethylhexanoic acid, 5,5 -Dimethylhexanoic acid, 2,3-dimethylhexanoic acid, 2,4-dimethylhexanoic acid, 2,5- Dimethylhexanoic acid, 3,4-dimethylhexanoic acid, 3,5-dimethylhexanoic acid, 4,5-dimethylhexanoic acid, 2,2,3-trimethylpentanoic acid, 2, 3,3-trimethylpentanoic acid, 2,4,4-trimethylpentanoic acid, 3,4,4-trimethylpentanoic acid, 2-ethylhexanoic acid, 3-ethylhexanoic acid, 2- Propyl valeric acid, 2- a combination of 1 to 25 of methyl-2-ethylpentanoic acid, 2-methyl-3-ethylpentanoic acid and 3-methyl-3-ethylpentanoic acid; (iii) selected from butyric acid, 2-methylpropionic acid, valeric acid, 2-methylbutyric acid, 3-methylbutyric acid, 2,2-dimethylpropionic acid, 2-methylpentanoic acid, 3-methylpentanoic acid, 4- 1 to 13 kinds of methylvaleric acid, 2,2-dimethylbutyric acid, 2,3-dimethylbutyric acid, 3,3-dimethylbutyric acid and caproic acid, and selected from 2-methyl Benzoic acid, 3-methyloctanoic acid, 4-methyloctanoic acid, 5-methyloctanoic acid, 6-methyloctanoic acid, 7-methyloctanoic acid, 8-methyloctanoic acid, 2,2-dimethylheptanoic acid, 3 ,3-dimethylheptanoic acid, 4,4-dimethylheptanoic acid, 5,5-dimethylheptanoic acid, 6,6-dimethylheptanoic acid, 2,3-dimethylheptanoic acid, 2 , 4-dimethylheptanoic acid, 2,5-dimethylheptanoic acid, 2,6-dimethylheptanoic acid, 3,4-dimethylheptanoic acid, 3,5-dimethylheptanoic acid, 3 ,6-dimethylheptanoic acid, 4,5-dimethylheptanoic acid, 4,6-dimethylheptanoic acid, 2-ethylheptanoic acid, 3-ethylheptanoic acid, 4-ethylheptanoic acid, 5-ethylheptanoic acid, 2-propylhexanoic acid, 3-propylhexanoic acid, 2-butylvaleric acid, 2,2,3-trimethylhexanoic acid, 2,2,3-trimethylhexyl Acid, 2,2,4-trimethylhexanoic acid, 2,2,5-trimethylhexanoic acid, 2,3,4-tri Hexanoic acid, 2,3,5-trimethylhexanoic acid, 3,3,4-trimethylhexanoic acid, 3,3,5-trimethylhexanoic acid, 3,5,5-trimethylhexyl Acid, 4,4,5-trimethylhexanoic acid, 4,5,5-trimethylhexanoic acid, 2,2,3,3-tetramethylpentanoic acid, 2,2,3,4-tetramethyl Valeric acid, 2,2,4,4-tetramethylpentanoic acid, 2,3,4,4-tetramethylpentanoic acid, 3,3,4,4-tetramethylpentanoic acid, 2,2- Diethyl valeric acid, 2,3-diethylpentanoic acid, 3,3-diethylpentanoic acid, 2-ethyl-2,3,3-trimethylbutyric acid, 3-ethyl-2, A combination of 1 to 50 of 2,3-trimethylbutyric acid and 2,2-diisopropylpropionic acid.

Further preferred examples of the acid component constituting the polyol fatty acid ester of the present invention include the following.

(i) 2-methylpropionic acid and selected from the group consisting of 2-methylhexanoic acid, 3-methylhexanoic acid, 4-methylhexanoic acid, 5-methylhexanoic acid, 2,2-dimethylvaleric acid, 2,3-dimethylvaleric acid, 2,4-dimethylvaleric acid, 3,3-dimethylvaleric acid, 3,4-dimethylvaleric acid, 4,4-dimethylvaleric acid, a combination of 1 to 13 of 2-ethylvaleric acid, 3-ethylpentanoic acid and 2-ethyl-3-methylbutyric acid; (ii) 2-methylpropionic acid and selected from 2-methyl Heptanoic acid, 3-methylheptanoic acid, 4-methylheptanoic acid, 5-methylheptanoic acid, 6-methylheptanoic acid, 2,2-dimethylhexanoic acid, 3,3-dimethylhexanoic acid 4,4-Dimethylhexanoic acid, 5,5-dimethylhexanoic acid, 2,3-dimethylhexanoic acid, 2,4-dimethylhexanoic acid, 2,5-dimethylhexanoic acid , 3,4-dimethylhexanoic acid, 3,5-dimethylhexanoic acid, 4,5-dimethylhexanoic acid, 2,2,3-trimethylpentanoic acid, 2,3,3-three Methylvaleric acid, 2,4,4-trimethylpentanoic acid, 3,4,4-trimethylpentanoic acid, 2-ethylhexanoic acid, 3-ethylhexanoic acid, 2-propylpentanoic acid, a combination of 1 to 25 of 2-methyl-2-ethylpentanoic acid, 2-methyl-3-ethylpentanoic acid and 3-methyl-3-ethylpentanoic acid; (iii) 2-A Propionic acid and selected from the group consisting of 2-methyloctanoic acid, 3-methyloctanoic acid, 4-methyloctanoic acid, 5-methyloctanoic acid, 6-methyloctanoic acid, 7-Methyloctanoic acid, 8-methyloctanoic acid, 2,2-dimethylheptanoic acid, 3,3-dimethylheptanoic acid, 4,4-dimethylheptanoic acid, 5,5-dimethylheptane Acid, 6,6-dimethylheptanoic acid, 2,3-dimethylheptanoic acid, 2,4-dimethylheptanoic acid, 2,5-dimethylheptanoic acid, 2,6-dimethylglycol Acid, 3,4-dimethylheptanoic acid, 3,5-dimethylheptanoic acid, 3,6-dimethylheptanoic acid, 4,5-dimethylheptanoic acid, 4,6-dimethylheptane Acid, 2-ethylheptanoic acid, 3-ethylheptanoic acid, 4-ethylheptanoic acid, 5-ethylheptanoic acid, 2-propylhexanoic acid, 3-propylhexanoic acid, 2-butylvaleric acid , 2,2,3-trimethylhexanoic acid, 2,2,3-trimethylhexanoic acid, 2,2,4-trimethylhexanoic acid, 2,2,5-trimethylhexanoic acid, 2 , 3,4-trimethylhexanoic acid, 2,3,5-trimethyl Hexanoic acid, 3,3,4-trimethylhexanoic acid, 3,3,5-trimethylhexanoic acid, 3,5,5-trimethylhexanoic acid, 4,4,5-trimethylhexyl Acid, 4,5,5-trimethylhexanoic acid, 2,2,3,3-tetramethylpentanoic acid, 2,2,3,4-tetramethylpentanoic acid, 2,2,4,4- Tetramethylpentanoic acid, 2,3,4,4-tetramethylpentanoic acid, 3,3,4,4-tetramethylpentanoic acid, 2,2-diethylpentanoic acid, 2,3-diethyl Valeric acid, 3,3-diethylpentanoic acid, 2-ethyl-2,3,3-trimethylbutyric acid, 3-ethyl-2,2,3-trimethylbutyric acid and 2, A combination of 1 to 50 of 2-diisopropylpropionic acid.

The content of the polyol fatty acid ester (A) is 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, and still more preferably 75% by mass or more based on the total amount of the refrigerator oil. The refrigerating machine oil of the present embodiment may contain a lubricating base oil or an additive other than the polyhydric alcohol fatty acid ester (A) as described below. However, if the polyhydric alcohol fatty acid ester (A) is less than 50% by mass, the necessary viscosity cannot be obtained. Coexistence with compatibility at a high level.

In the refrigerating machine oil of the present embodiment, the polyol fatty acid ester (A) is mainly used as a base oil. As the base oil of the refrigerating machine oil of the present embodiment, the polyol fatty acid ester (A) can be used alone (that is, the content of the polyhydric alcohol fatty acid ester (A) is 100% by mass), and the quality of the base oil can be excellent. The degree of performance further contains a base oil other than the polyol fatty acid ester (A). Examples of the base oil other than the polyol fatty acid ester (A) include hydrocarbon oils such as mineral oil, olefin polymer alkyl diphenyl alkane, alkyl naphthalene, and alkyl benzene; and polyol fatty acid esters (A). Other than esters such as polyol esters, complex esters, and alicyclic dicarboxylates, polyethylene glycol, polyvinyl ether, ketone, polyphenyl ether, polyfluorene oxide, polyoxyalkylene, perfluoroether, etc. Oxygen synthetic oil (hereinafter referred to as "other oxygen-containing synthetic oil").

As the oxygen-containing synthetic oil, among the above, esters other than the polyol fatty acid ester (A), polyethylene glycol, polyvinyl ether, and more preferably polyols other than the polyol fatty acid ester (A) are preferable. Alcohol ester. Examples of the polyol ester other than the polyol fatty acid ester (A) include polyhydric alcohols such as neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, and dipentaerythritol. Esters with fatty acids, especially esters of neopentyl glycol with fatty acids, esters of pentaerythritol with fatty acids and esters of dipentaerythritol with fatty acids.

As the neopentyl glycol ester, an ester of neopentyl glycol and a fatty acid having 5 to 9 carbon atoms is preferred. Specific examples of such a neopentyl glycol ester include neopentyl glycol di(3,5,5-trimethylhexanoate) and neopentyl glycol di(2-ethylhexanoate). , neopentyl glycol bis(2-methylhexanoate), neopentyl glycol di(2-ethylvalerate), neopentyl glycol and 2-methylhexanoic acid and 2-ethylpentanoic acid Esters, esters of neopentyl glycol with 3-methylhexanoic acid and 5-methylhexanoic acid, esters of neopentyl glycol with 2-methylhexanoic acid and 2-ethylhexanoic acid, neopentyl glycol and 3 , 5-dimethylhexanoic acid, 4,5-dimethylhexanoic acid and 3,4-dimethylhexanoic acid ester, neopentyl glycol divalerate, neopentyl glycol di(2-ethyl Butyrate), neopentyl glycol bis(2-methylvalerate), neopentyl glycol bis(2-methylbutyrate), neopentyl glycol bis(3-methylbutyrate), etc. .

As the pentaerythritol ester, an ester of pentaerythritol and a fatty acid having 5 to 9 carbon atoms is preferable. Specific examples of such pentaerythritol esters include pentaerythritol and a compound selected from the group consisting of valeric acid, 2-methylbutyric acid, 3-methylbutyric acid, caproic acid, 2-methylpentanoic acid, and 2-ethylbutyric acid. An ester of one or more of 2-ethylpentanoic acid, 2-methylhexanoic acid, 3,5,5-trimethylhexanoic acid, and 2-ethylhexanoic acid.

As the dipentaerythritol ester, an ester of dipentaerythritol and a fatty acid having 5 to 9 carbon atoms is preferable. Specific examples of such dipentaerythritol esters include: Dipentaerythritol and selected from the group consisting of valeric acid, 2-methylbutyric acid, 3-methylbutyric acid, caproic acid, 2-methylpentanoic acid, 2-ethylbutyric acid, 2-ethylpentanoic acid, 2-methyl An ester of one or more of hexanoic acid, 3,5,5-trimethylhexanoic acid and 2-ethylhexanoic acid.

In the case where the refrigerating machine oil of the present embodiment contains an oxygen-containing synthetic oil other than the polyhydric alcohol fatty acid ester (A), the content of the oxygen-containing synthetic oil other than the polyhydric alcohol fatty acid ester (A) is not impaired in the refrigerating machine oil of the present embodiment. The excellent lubricity and compatibility are not particularly limited, and in the case of blending a polyol ester other than the polyol fatty acid ester (A), it is preferably less than 50% by mass based on the total amount of the refrigerating machine oil. More preferably, it is 45% by mass or less, further preferably 40% by mass or less, further preferably 35% by mass or less, further preferably 30% by mass or less, and most preferably 25% by mass or less; and other than the polyol ester In the case of the oxygen-containing synthetic oil, it is preferably less than 50% by mass, more preferably 40% by mass or less, and still more preferably 30% by mass or less based on the total amount of the refrigerating machine oil. If the amount of the polyol ester other than the pentaerythritol fatty acid ester or other oxygen-containing synthetic oil is too large, the characteristics of the present invention cannot be obtained.

Further, the polyol ester other than the polyol fatty acid ester (A) may be a partial ester which is partially esterified by a hydroxyl group of the polyol and remains as a hydroxyl group, or may be a complete esterification of all the hydroxyl groups. The ester may be a mixture of a partial ester and a complete ester, and the hydroxyl value is preferably 10 mgKOH/g or less, more preferably 5 mgKOH/g or less, and most preferably 3 mgKOH/g or less.

When the refrigerating machine oil and the refrigerating machine of the present embodiment are used as a dynamic fluid composition containing a polyol ester other than the polyhydric alcohol fatty acid ester (A), the polyhydric alcohol ester may contain a polyol ester containing a single structure. ,also, A mixture of two or more kinds of polyol esters having different structures may also be contained.

Further, the polyol ester other than the polyhydric alcohol fatty acid ester (A) may be an ester of a fatty acid and a polyhydric alcohol, an ester of two or more kinds of fatty acids and one polyhydric alcohol, an ester of one fatty acid and two or more kinds of polyhydric alcohols, Any one of two or more kinds of fatty acids and esters of two or more kinds of polyols.

The refrigerating machine oil of the present embodiment may be one containing only the polyhydric alcohol fatty acid ester (A), or may be a polyhydric alcohol fatty acid ester (A) or another base oil, and may further contain various additives as described below. Further, the refrigerator of the present embodiment may further contain various additives as the fluid dynamic fluid composition. Further, in the following description, the content of the additive is expressed on the basis of the total amount of the refrigerating machine oil, and the content of the components in the refrigerating machine used as the dynamic fluid composition is preferably based on the total amount of the refrigerating machine oil. In the case, it is selected so as to be within a preferred range to be described later.

In order to further improve the wear resistance and load resistance of the refrigerating machine oil and the refrigerating machine of the present embodiment, the amine salt selected from the group consisting of phosphate ester, acid phosphate ester, phosphorothioate, and acid phosphate ester may be selected. At least one phosphorus compound of the group consisting of chlorinated phosphates and phosphites. The phosphorus compounds are esters of phosphoric acid or phosphorous acid with alkanols, polyether alcohols or derivatives thereof.

Specifically, examples of the phosphate ester include tributyl phosphate, triamyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, tridecyl phosphate, tridecyl phosphate, and phosphoric acid tri Undecyl)ester, tris(dodecyl)phosphate, tris(tridecyl)phosphate, tris(tetradecyl)phosphate, tris(pentadecyl)phosphate, phosphate III Cetyl ester, tris(heptadecane) Ester, tris(octadecyl)phosphate, trioleyl phosphate, triphenyl phosphate, tricresyl phosphate, tris(dimethylphenyl) phosphate, cresyl diphenyl phosphate, xylyl phosphate Diphenyl ester and the like.

Examples of the acidic phosphate include acid monobutyl phosphate, acid monoamyl phosphate, acid monohexyl phosphate, acid monoheptyl phosphate, acid monooctyl phosphate, acid monodecyl phosphate, and acid monodecyl phosphate. Acidic acid monoundecyl ester, acid monododecyl phosphate, acid monotridecyl phosphate, acid monotetradecyl phosphate, acid monopentadecyl phosphate, acid phosphate Alkyl ester, acid monoheptadecyl phosphate, acid monostearyl phosphate, acid monophosphate, acid dibutyl phosphate, acid diamyl phosphate, acid dihexyl phosphate, acid diphosphonate Ester, acid dioctyl phosphate, acid dinonyl ester, acid dinonyl ester, acid di(undecyl) phosphate, acid di-dodecyl ester, acid di(tridecane) Ester, acid di(tetradecyl) phosphate, dipentadecyl phosphate, acid di(hexadecyl) phosphate, acid di(heptadecyl) acidate, acid Dioctadecyl phosphate, acid diesterate, and the like.

Examples of the phosphorothioate include tributyl thiophosphate, triamyl thiophosphate, trihexyl thiophosphate, triheptyl thiophosphate, trioctyl thiophosphate, and tridecyl thiophosphate. , tridecyl thiophosphate, tris(undecyl) thiophosphate, tris(dodecyl) thiophosphate, tris(tridecyl) thiophosphate, thiophosphoric acid tris(10) Tetraalkyl) ester, tris(pentadecyl) thiophosphate, tris(hexadecyl) thiophosphate, tris(heptadecyl) thiophosphate, trisoctadecyl thiophosphate Ester, trioleyl thiophosphate, thio Triphenyl phosphate, cresyl thiophosphate, tris(dimethylphenyl) thiophosphate, cresyl diphenyl thiophosphate, diphenyl thiophosphate, and the like.

The amine salt of the acidic phosphate ester may, for example, be an amine salt of an acid phosphate and an amine having a linear or branched alkyl group having 1 to 24 carbon atoms, preferably 5 to 18 or 1 to 3 linear groups.

Examples of the amine constituting the amine salt of the acidic phosphate include a linear or branched methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, and anthracene. Amine, mercaptoamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, ten Octaamine, oleylamine, tetracosylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, two Octylamine, dinonylamine, didecylamine, di(undecyl)amine, di(dodecyl)amine, ditridecylamine, di(tetradecyl)amine, Di(pentadecyl)amine, dihexadecylamine, dihexadecylamine, dioctadecylamine, dioleylamine, di(tetracosyl)amine, Trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, tridecylamine, tridecylamine, three (undecyl)amine, tris(dodecyl)amine, tris(tridecyl)amine, tris(tetradecyl)amine, tris(pentadecyl)amine , tris(hexadecyl)amine, tris(heptadecyl)amine, tris(octadecyl)amine, trioleylamine, tris(tetracosyl)amine, and the like. The amine may be a single compound or a mixture of two or more compounds.

Examples of the chlorinated phosphate include tris(dichloropropyl) phosphate, tris(chloroethyl) phosphate, tris(chlorophenyl) phosphate, and polyoxyalkylene phosphate. (Chloroalkyl)] ester and the like. Examples of the phosphite include dibutyl phosphite, diamyl phosphite, dihexyl phosphite, diheptyl phosphite, dioctyl phosphite, dinonyl phosphite, dinonyl phosphite, Di(undecyl) phosphite, di(dodecyl) phosphite, dioleyl phosphite, diphenyl phosphite, dimethyl phosphite, tributyl phosphite, phosphorous triacetate Amyl ester, trihexyl phosphite, triheptyl phosphite, trioctyl phosphite, tridecyl phosphite, tridecyl phosphite, tri (undecyl) phosphite, tris (twelve) Alkyl) ester, trioleyl phosphite, triphenyl phosphite, cresyl phosphite, and the like. Also, mixtures of these may be used.

In the case where the refrigerating machine oil and the refrigerating machine of the present embodiment are used as the dynamic fluid composition containing the phosphorus compound, the content of the phosphorus compound is not particularly limited, and based on the total amount of the refrigerating machine oil (the total amount of the base oil and all the blending additives) The basis) is preferably 0.01 to 5.0% by mass, more preferably 0.02 to 3.0% by mass. Further, the above-mentioned phosphorus compounds may be used alone or in combination of two or more.

Further, the refrigerating machine oil and the refrigerating machine of the present embodiment are used as a hydrodynamic fluid composition. In order to further improve the thermo-chemical stability, a terpene compound may be added. The "terpene compound" in the present invention means a compound obtained by polymerizing isoprene and derivatives thereof, and a 2-8 polymer of isoprene can be preferably used. Specific examples of the terpene compound include geraniol, nerol, linalool, citral (containing geranyl aldehyde), citronellol, menthol, anthraquinone, rosin, geranone, and violet. Ketones, flavonoids, camphors, borneol and other monoterpenes, farnesene, farnesol, neroli, young hormones, hops, caryophyllene, lenene, juniper, du Pinene, hydroxyl A sesquiterpene, such as geranyl toxin, geranylgeranol, phytol, rosin acid, sea pine diene, ruthenium toxin, paclitaxel, cedar acid, etc. Squalene, limonin, camellia saponin, valerane, lanosterol, triterpene, carotenoid and other tetraterpenes.

Among the terpene compounds, preferred are monoterpenes, sesquiterpenes, diterpenes, more preferably sesquiterpenes, and particularly preferably α-cainene (3,7,11-trimethyl-12) Carbon-1,3,6,10-tetraene) and/or β-farnesene (7,11-dimethyl-3-methylenedodeca-1,6,10-triene). In the present invention, the terpene compounds may be used alone or in combination of two or more.

The content of the terpene compound in the refrigerating machine oil of the present embodiment is not particularly limited, and is preferably 0.001 to 10% by mass, more preferably 0.01 to 5% by mass, still more preferably 0.05%, based on the total amount of the refrigerating machine oil. 3 mass%. When the content of the terpene compound is less than 0.001% by mass, the effect of improving the thermo-chemical stability tends to be insufficient, and if it exceeds 10% by mass, the lubricity tends to be insufficient. Further, the content of the terpene compound used in the fluid dynamic fluid composition of the refrigerator of the present embodiment is preferably selected so as to be within the above preferred range in the case of the total amount of the refrigerating machine oil.

Further, the refrigerating machine oil and the refrigerating machine of the present embodiment are used as a dynamic fluid composition, and may further contain a phenyl glycidyl ether type epoxy compound or an alkyl glycidyl ether type epoxy compound, in order to further improve the thermo-chemical stability. a glycidyl ester type epoxy compound, an allyl oxirane compound, an alkyl oxirane compound, an alicyclic epoxy compound, an epoxidized fatty acid monoester, and At least one epoxy compound in the epoxidized vegetable oil.

Specific examples of the phenyl glycidyl ether type epoxy compound include phenyl glycidyl ether or alkylphenyl glycidyl ether. The alkylphenyl glycidyl ether is exemplified by having 1 to 3 alkyl groups having 1 to 13 carbon atoms. Preferred examples thereof include those having an alkyl group having 4 to 10 carbon atoms, for example. : n-butylphenyl glycidyl ether, isobutylphenyl glycidyl ether, second butyl phenyl glycidyl ether, tert-butylphenyl glycidyl ether, amyl phenyl glycidyl ether, hexyl phenyl Glycidyl ether, heptylphenyl glycidyl ether, octylphenyl glycidyl ether, nonylphenyl glycidyl ether, nonylphenyl glycidyl ether, and the like.

Specific examples of the alkyl glycidyl ether type epoxy compound include mercapto glycidyl ether, undecyl glycidyl ether, lauryl glycidyl ether, tridecyl glycidyl ether, and tetradecane. Glycidyl ether, 2-ethylhexyl glycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1,6-hexanediol diglycidyl ether , sorbitol polyglycidyl ether, polyalkylene glycol monoglycidyl ether, polyalkylene glycol diglycidyl ether, and the like.

Specific examples of the glycidyl ester type epoxy compound include phenyl glycidyl ester, alkyl glycidyl ester, and alkenyl glycidyl ester. Preferred examples thereof include 2,2-dimethyloctanoic acid. Glycidyl ester, glycidyl benzoate, glycidyl acrylate, glycidyl methacrylate, and the like.

Specific examples of the allyl oxirane compound include 1,2-epoxystyrene, alkyl-1,2-epoxystyrene, and the like.

Specific examples of the alkyl oxirane compound include 1,2-butylene oxide, 1,2-epoxypentane, 1,2-epoxyhexane, and 1,2-epoxy heptane. 1,2-epoxyoctane, 1,2-epoxydecane, 1,2-epoxydecane, 1,2-epoxyundecane, 1,2-epoxydodecane, 1, 2-epoxytridecane, 1,2-epoxytetradecane, 1,2-epoxypentadecane, 1,2-epoxyhexadecane, 1,2-epoxyheptadecane, 1, 2-epoxyoctadecane, 1,2-epoxynonadecane, 1,2-epoxyecosane, and the like.

Specific examples of the alicyclic epoxy compound include 1,2-epoxycyclohexane, 1,2-epoxycyclopentane, and 3,4-epoxycyclohexanecarboxylic acid-(3,4). -Epoxycyclohexylmethyl)ester, bis(3,4-epoxycyclohexylmethyl) adipate, external 2,3-epoxy drop Alkane, bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, 2-(7-oxabicyclo[4.1.0]heptan-3-yl)-spiro (1, 3-two Alkane-5,3'-[7]oxabicyclo[4.1.0]heptane, 4-(1'-methyloxiranyl)-1,2-epoxy-2-methylcyclohexane , 4-epoxyethyl-1,2-epoxycyclohexane, and the like.

Specific examples of the epoxidized fatty acid monoester include an epoxidized fatty acid having 12 to 20 carbon atoms, an alcohol having 1 to 8 carbon atoms, an ester of an alkylphenol, and the like. In particular, butyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl, phenyl and butylphenyl esters of epoxy stearic acid can be preferably used.

Specific examples of the epoxidized vegetable oil include epoxy compounds of vegetable oils such as soybean oil, linseed oil, and cottonseed oil.

Among these epoxy compounds, a phenyl glycidyl ether type epoxy compound, an alkyl glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, and an alicyclic epoxy compound are preferable.

When the refrigerating machine oil and the refrigerating machine of the present embodiment are used as the dynamic fluid composition containing the epoxy compound, the content of the epoxy compound is not particularly The limitation is preferably 0.01 to 5.0% by mass, more preferably 0.1 to 3.0% by mass based on the total amount of the refrigerating machine oil. Further, the above epoxy compounds may be used alone or in combination of two or more.

Further, the refrigerating machine oil and the refrigerating machine of the present embodiment are used as a dynamic fluid composition, and may further contain a conventionally known additive for refrigerating machine oil, in order to further improve the performance. Examples of the additive include phenolic antioxidants such as di-t-butyl-p-cresol and bisphenol A, phenyl-α-naphthylamine, and N,N-bis(2-naphthyl)-p-phenylenediamine. An amine-based antioxidant, an anti-wear agent such as zinc dithiophosphate, an extreme pressure additive such as chlorinated paraffin or a sulfur compound, an oily agent such as a fatty acid, an antifoaming agent such as polyfluorene, and a metal deactivator such as benzotriazole. , acid scavengers such as carbodiimide, viscosity index improvers, pour point depressants, cleaning dispersants, etc. These additives may be used alone or in combination of two or more. The content of the additives is not particularly limited, and is preferably 10% by mass or less, and more preferably 5% by mass or less based on the total amount of the refrigerating machine oil.

The dynamic viscosity of the refrigerating machine oil of the present embodiment is not particularly limited, and the dynamic viscosity at 40 ° C can be preferably 20 to 80 mm ² /s, more preferably 25 to 75 mm ² /s, and most preferably The ground is set to 30~70 mm ² /s. Further, the dynamic viscosity at 100 ° C can be preferably 2 to 20 mm ² /s, more preferably 3 to 10 mm ² /s. When the dynamic viscosity is less than the above lower limit, the viscosity necessary for the refrigerator oil cannot be obtained. On the other hand, if the viscosity exceeds the above upper limit, the compatibility with the difluoromethane refrigerant tends to be insufficient. .

Further, the volume resistivity of the refrigerator oil of the present embodiment is not particularly limited, but is preferably 1.0 × 10 ¹² Ω. More than cm, more preferably set to 1.0 × 10 ¹³ Ω. Above cm, optimally set to 1.0 × 10 ¹⁴ Ω. More than cm. In particular, when used in a closed type refrigerator, there is a tendency for high electrical insulation to be required. In the present invention, the volume resistivity means a value at 25 ° C measured in accordance with JIS C 2101 "Test method for electrical insulating oil".

In addition, the moisture content of the refrigerating machine oil of the present embodiment is not particularly limited, and is preferably 200 ppm or less, more preferably 100 ppm or less, and most preferably 50 ppm, based on the total amount of the refrigerating machine oil. the following. In particular, when used in a closed type refrigerator, the moisture content is required to be small from the viewpoint of the influence of the thermo-chemical stability or electrical insulation of the refrigerating machine oil.

In addition, the acid value of the refrigerating machine oil of the present embodiment is not particularly limited, and is preferably 0.1 mg KOH/g or less, more preferably 0.05 mg KOH / in order to prevent corrosion of the metal used in the refrigerator or the piping. g below. In the present invention, the acid value means an acid value measured in accordance with JIS K 2501 "Petroleum Products and Lubricating Oil - Neutralization Value Test Method".

Further, the ash content of the refrigerating machine oil of the present embodiment is not particularly limited, and is preferably 100 ppm or less, and more preferably 50 ppm, in order to improve the thermo-chemical stability of the refrigerating machine oil and suppress the generation of sediment or the like. the following. Further, in the present invention, the term "ash" means the value of ash measured in accordance with JIS K 2272 "Assay for ash and sulfuric acid ash of crude oil and petroleum products".

When the refrigerating machine oil of the present embodiment is used in combination with a difluoromethane refrigerant, it exhibits sufficiently high lubricity and sufficiently high compatibility, and can be widely used as a refrigerating machine oil for a refrigerator for a difluoromethane refrigerant. As available Specific examples of the refrigerator for the refrigerator oil according to the present embodiment include cooling of indoor air conditioners, cabinet air conditioners, refrigerators, automobile air conditioners, dehumidifiers, freezers, refrigerated warehouses, vending machines, display cabinets, and chemical factories. A device or the like, which can be preferably used in a refrigerator having a hermetic compressor. Further, the refrigerating machine oil for a difluoromethane refrigerant of the present invention can also be used in a compressor of any type such as a reciprocating type, a rotary type, or a centrifugal type. Further, in the refrigerators, the refrigerator oil of the present invention can be used as a dynamic fluid composition as a refrigerator mixed with a refrigerant as described below.

That is, the refrigerator of the present embodiment is used as a dynamic fluid composition and is characterized by comprising the above-described refrigerator oil and refrigerant of the present embodiment. Here, the ratio of the ratio of the refrigerating machine oil to the refrigerant used in the fluid dynamic fluid composition of the refrigerating machine of the present embodiment is not particularly limited, and the amount of the refrigerating machine oil is usually 1 to 1000 parts by mass based on 100 parts by mass of the refrigerant. 2 to 800 parts by mass.

Further, in the case where the refrigerator of the present embodiment is used as the dynamic fluid composition, it is possible to provide a sufficiently high lubricity which cannot be obtained when the conventional refrigerating machine oil is used, and a sufficiently high compatibility. When the difluoromethane refrigerant is contained as a refrigerant component, it is most useful. However, it may contain HFC refrigerant other than difluoromethane refrigerant, unsaturated fluorinated hydrocarbon (HFO) refrigerant, trifluoroiodomethane refrigerant, and perfluoroether. A fluorine-containing ether-based refrigerant such as a fluoridyl ether-based refrigerant, a non-fluorine-containing refrigerant such as dimethyl ether, or a natural refrigerant such as ammonia, carbon dioxide (CO ₂ ) or hydrocarbon.

Examples of the HFC refrigerant other than difluoromethane include hydrofluorocarbons having a carbon number of 1 to 3, preferably 1 to 2. Specific examples thereof include trifluoromethane (HFC-23), pentafluoroethane (HFC-125), and 1,1,2,2-tetrafluoroethane (HFC-). 134), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a) , fluoroethane (HFC-161), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,1,2,3,3-hexafluoropropane (HFC-236ea ), 1,1,1,3,3,3-hexafluoropropane (HFC-236fa), 1,1,1,3,3-pentafluoropropane (HFC-245fa) and 1,1,1,3, 3-pentafluorobutane (HFC-365mfc), or a mixture of two or more of these. These refrigerants are appropriately selected depending on the use or required performance. Preferred examples include, for example, HFC-32 alone; HFC-23 alone; HFC-134a alone; HFC-125 alone; HFC-134a/ HFC-32=60~80% by mass/40~20% by mass of mixture; HFC-32/HFC-125=40~70%%/60~30% by mass of mixture; HFC-125/HFC-143a=40~ a mixture of 60% by mass/60 to 40% by mass; a mixture of HFC-134a/HFC-32/HFC-125=60% by mass/30% by mass/10% by mass; HFC-134a/HFC-32/HFC-125= 40~70% by mass/15~35 mass%/5~40% by mass of mixture; HFC-125/HFC-134a/HFC-143a=35~55 mass%/1~15% by mass/40~60% by mass Mixture, etc. More specifically, a mixture of HFC-134a/HFC-32=70/30% by mass; a mixture of HFC-32/HFC-125=60/40% by mass; HFC-32/HFC-125=50/ a mixture of 50% by mass (R410A); a mixture of HFC-32/HFC-125=45/55 mass% (R410B); a mixture of HFC-125/HFC-143a=50/50% by mass (R507C); HFC-32 /HFC-125/HFC-134a=30/10/60% by mass of mixture; HFC-32/HFC-125/HFC-134a=23/25/52% by mass of mixture (R407C); HFC-32/HFC- 125/HFC-134a=25/15/60% by mass of mixture (R407E); HFC-125/HFC-134a/HFC-143a=44/4/52 A mixture of % (R404A) and the like.

As the unsaturated hydrogen fluoride (HFO) refrigerant, fluoropropene having a fluorine number of 3 to 5 is preferable, and 1,2,3,3,3-pentafluoropropene (HFO-1225ye), 1,3, is preferable. 3,3-tetrafluoropropene (HFO-1234ze), 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,2,3,3-tetrafluoropropene (HFO-1234ye) and 3,3 Any one or a mixture of two or more of 3-trifluoropropene (HFO-1243zf). Further, in the above, it is preferred to contain HFC-32 and HFO-1234yf as a refrigerant, and the mass ratio of HFC-32:HFO-1234yf is 95:5 to 50:50. From the viewpoint of the properties of the refrigerant, it is preferably one or more selected from the group consisting of HFO-1225ye, HFO-1234ze, and HFO-1234yf.

The hydrocarbon refrigerant is preferably a hydrocarbon having 1 to 5 carbon atoms, and specific examples thereof include methane, ethylene, ethane, propylene, propane (R290), cyclopropane, n-butane, isobutane, and cyclobutane. Alkane, methylcyclopropane, 2-methylbutane, n-pentane or a mixture of two or more thereof. Among these, it can be preferably used as a gas at 25 ° C and 1 atm., preferably propane, n-butane, isobutane, 2-methylbutane or a mixture thereof.

Specific examples of the fluorine-containing ether-based refrigerant include HFE-134p, HFE-245mc, HFE-236mf, HFE-236me, HFE-338mcf, HFE-365mcf, HFE-245mf, HFE-347mmy, and HFE-347mcc. HFE-125, HFE-143m, HFE-134m, HFE-227me, etc., and these refrigerants are suitably selected depending on the use or performance.

The refrigerating machine oil of the present embodiment is usually used as a fluid dynamic fluid composition in a refrigerating and air-conditioning apparatus in which a refrigerating machine that is mixed with a refrigerant is used. The ratio of the refrigerating machine oil to the refrigerant in the composition, and the refrigerator of the present invention The ratio of the ratio of the refrigerating machine oil to the refrigerant in the actuating fluid composition is not particularly limited, and the refrigerating machine oil is preferably from 1 to 500 parts by mass, more preferably from 2 to 400 parts by mass, per 100 parts by mass of the refrigerant.

The refrigerating machine oil and the refrigerating machine of the present embodiment are preferably used as a dynamic fluid composition for an air conditioner, a refrigerator, or an open or sealed type automobile air conditioner having a reciprocating type or a rotary type hermetic compressor. Further, the refrigerating machine oil and the refrigerating machine of the present embodiment are preferably used as a dynamic fluid composition in a cooling device such as a dehumidifier, a water heater, a freezer, a refrigerating warehouse, a vending machine, a display case, a chemical factory, or the like. Further, the refrigerating machine oil and the refrigerating machine of the present embodiment can be preferably used as a dynamic fluid composition in a centrifugal compressor.

The refrigerating machine of the present embodiment can be preferably used as a refrigerating machine for various difluoromethane refrigerants as described above, and as a representative configuration of the refrigerant circulation circuit provided in the refrigerating machine, a compressor can be exemplified. Condenser, expansion mechanism and evaporator, and if necessary, dryer.

The compressor is exemplified by a high-pressure container type compressor in which a motor including a rotor and a stator, a rotating shaft embedded in the rotor, and the above-described rotor are connected to the above-described rotor in a sealed container in which the refrigerator oil is stored. a compressor unit on the motor, and a high-pressure refrigerant gas ejected from the compressor unit is retained in the sealed container; and a compressor of the low-pressure container type or the like: a motor including a rotor and a stator is housed in a sealed container in which the refrigerating machine oil is stored a rotating shaft embedded in the rotor and a compressor unit connected to the motor via the rotating shaft, and the high-pressure refrigerant gas discharged from the compressor unit is directly discharged to the outside of the sealed container.

The insulating film of the electrical insulation system material of the motor portion, the crystalline plastic film having a glass transition point of 50 ° C or higher, specifically, for example, selected from the group consisting of polyethylene terephthalate and polybutylene terephthalate. At least one insulating film of polyphenylene sulfide, polyetheretherketone, polyethylene naphthalate, polyamidimide, polyimine, or coated on a film having a lower glass transition temperature A composite film of a resin layer having a high glass transition temperature can be preferably used because it is difficult to cause deterioration of tensile strength characteristics and electrical insulating properties. Further, as the magnetic wire used in the motor portion, it is preferable to use an enamel coating having a glass transition temperature of 120 ° C or higher, such as a polyester, a polyester phthalimide, a polyamide, and a polyamidimide. One layer, or an enamel coating having a lower layer of glass transition temperature as a lower layer and a layer having a higher glass transition temperature as an upper layer. As the composite coated enamel line, a polyester ylidene is used as a lower layer and a polyamidoximine is used as an upper layer to coat (AI/EI), and a polyester as a lower layer and a polyamidoxime. The amine is an upper layer and is covered (AI/PE) or the like.

As the desiccant filled in the desiccator, it is preferable to use a tantalum acid or an alkali metal aluminate having a pore diameter of 3.3 angstroms or less and a carbonic acid gas partial pressure of 250 mmHg at 25 ° C of 1.0% or less. Synthetic zeolite of a composite salt. Specifically, for example, trade names XH-9, XH-10, XH-11, and XH-600 manufactured by UNION SHOWA Co., Ltd. may be mentioned.

[Examples]

Hereinafter, the present invention will be specifically described based on examples and comparative examples, but the present invention is not limited to the following examples.

[Examples 1 to 36 and Comparative Examples 1 to 15]

In Examples 1 to 36 and Comparative Examples 1 to 15, the base oils 1 to 36 and the additives 1 to 5 shown below were prepared in such a manner as to have the composition ratios shown in Tables 1 to 10 to prepare samples. oil. The properties of each of the obtained sample oils are shown in Tables 1 to 10.

(base oil)

Base oil 1: tetraester of pentaerythritol and fatty acid mixture (30 mol% of 2-methylpropionic acid, 70 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 2: tetraester of pentaerythritol and fatty acid mixture (mixture of 35 mol% of 2-methylpropionic acid and 65 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 3: tetraester of pentaerythritol and fatty acid mixture (50 mol% of 2-methylpropionic acid, 50 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 4: tetraester of pentaerythritol and fatty acid mixture (mixture of 60 mol% of 2-methylpropionic acid and 40 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 5: tetraester of pentaerythritol and fatty acid mixture (a mixture of 70 mol% of 2-methylpropionic acid and 30 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 6: tetraester of pentaerythritol and fatty acid mixture (mixture of 2-methylpropionic acid 30 mol%, 2-ethylhexanoic acid 70 mol%)

Base oil 7: tetraester of pentaerythritol and fatty acid mixture (mixture of 2-methylpropionic acid 35 mol%, 2-ethylhexanoic acid 65 mol%)

Base oil 8: tetraester of pentaerythritol and fatty acid mixture (mixture of 2-methylpropionic acid 70 mol%, 2-ethylhexanoic acid 30 mol%)

Base oil 9: tetraester of pentaerythritol and fatty acid mixture (mixture of 2-methylpropionic acid 30 mol%, 2-methylhexanoic acid 35 mol%, 2-ethylpentanoic acid 35 mol%)

Base oil 10: a mixture of pentaerythritol and a fatty acid (2-methylpropionic acid 70 mol%, a tetraester of a mixture of 15 mol% of 2-methylhexanoic acid and 15 mol% of 2-ethylpentanoic acid)

Base oil 11: tetraester of pentaerythritol and fatty acid mixture (30 mol% of 2-methylpropionic acid, 60 mol% of 3,5,5-trimethylhexanoic acid, and 10 mol% of 2-methylbutyric acid)

Base oil 12: tetraester of pentaerythritol and fatty acid mixture (60 mol% of 2-methylpropionic acid, 30 mol% of 3,5,5-trimethylhexanoic acid, and 10 mol% of 2-methylbutyric acid)

Base oil 13: tetraester of pentaerythritol and fatty acid mixture (15 mol% of 2-methylpropionic acid, 35 mol% of 3,5,5-trimethylhexanoic acid, and 50 mol% of 2-methylbutyric acid)

Base oil 14: tetraester of pentaerythritol and fatty acid mixture (35 mol% of 2-methylpropionic acid, 15 mol% of 3,5,5-trimethylhexanoic acid, and 50 mol% of 2-methylbutyric acid)

Base oil 15: tetraester of pentaerythritol and fatty acid mixture (20 mol% of 2-methylpropionic acid, 30 mol% of 3,5,5-trimethylhexanoic acid, and 50 mol% of 2-methylpentanoic acid)

Base oil 16: pentaerythritol and fatty acid mixture (20 mol% of 2-methylpropionic acid, 30 mol% of 3,5,5-trimethylhexanoic acid, 25 mol% of 2-ethylpentanoic acid, 2-methylhexanoic acid 25 mol% mixture) tetraester

Base oil 17: tetraester of pentaerythritol and fatty acid mixture (30 mol% of 2-methylpropionic acid, 50 mol% of 2-ethylhexanoic acid, 20 mol% of 2-methylpentanoic acid)

Base oil 18: a mixture of pentaerythritol and fatty acid (25 mol% of 2-methylpropionic acid, 45 mol% of 2-ethylhexanoic acid, 15 mol% of 2-ethylpentanoic acid, and 15 mol% of 2-methylhexanoic acid) Tetraester

Base oil 19: a triester of a mixture of trimethylolpropane and a fatty acid (a mixture of 30 mol% of 2-methylpropionic acid and 70 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 20: hexaester of dipentaerythritol and a mixture of fatty acids (a mixture of 70 mol% of 2-methylpropionic acid and 30 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 21: tetraester of pentaerythritol and 2-methylpropionic acid

Base oil 22: pentaerythritol and tetraester of propionic acid

Base oil 23: tetraester of pentaerythritol and n-butyric acid

Base oil 24: tetraester of pentaerythritol and 2-ethylhexanoic acid

Base oil 25: tetraester of pentaerythritol and fatty acid mixture (50 mol% of 2-ethylhexanoic acid, 50 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 26: tetraester of pentaerythritol and 3,5,5-trimethylhexanoic acid

Base oil 27: tetraester of pentaerythritol and fatty acid mixture (30 mol% of propionic acid, 70 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 28: tetraester of pentaerythritol and fatty acid mixture (25 mol% of n-butyric acid, 75 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 29: tetraester of pentaerythritol and fatty acid mixture (65 mol% of n-butyric acid, 35 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 30: tetraester of pentaerythritol and fatty acid mixture (10 mol% of 2-methylpropionic acid, 90 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 31: tetraester of pentaerythritol and fatty acid mixture (mixture of 2-methylbutyric acid 90 mol%, 3,5,5-trimethylhexanoic acid 10 mol%)

Base oil 32: tetraester of pentaerythritol and fatty acid mixture (30 mol% of 2-methylbutyric acid, 70 mol% of 3,5,5-trimethylhexanoic acid)

Base oil 33: a mixture of pentaerythritol and a fatty acid (2-methylbutyric acid 60 mol%, a tetraester of a mixture of 3,5,5-trimethylhexanoic acid 40 mol%)

Base oil 34: tetraester of pentaerythritol and fatty acid mixture (mixture of 2-methylpentanoic acid 30 mol%, 3,5,5-trimethylhexanoic acid 70 mol%)

Base oil 35: diester of neopentyl glycol and 2-ethylhexanoic acid

Base oil 36: hexaester of dipentaerythritol and fatty acid mixture (50 mol% of 2-ethylhexanoic acid, 50 mol% of 3,5,5-trimethylhexanoic acid); dynamic viscosity at 40 ° C: 249.9 mm ² / s, dynamic viscosity at 100 ° C: 19.58 mm ² / s

(additive)

Additive 1: Tricresyl phosphate

Additive 2: Triphenyl thiophosphate

Additive 3: 2,2-dimethyl octanoate glycidyl ester

Additive 4: p-tert-butylphenyl glycidyl ether

Additive 5: di-tert-butyl-p-cresol

Then, the refrigerators of Examples 1 to 36 and Comparative Examples 1 to 15 were subjected to the tests shown below.

(Compatibility test with refrigerant)

According to the "Test Method for Compatibility with Refrigerant" of JIS K 2211 "Refrigerating Machine Oil", the mixture of 18 g of various refrigerants shown in Tables 1 to 8 and 2 g of sample oil was gradually cooled from 20 ° C to -40. °C, the temperature at which the mixture was phase-separated or clouded was taken as the two-layer separation temperature and evaluated. In addition, "<-40" means that phase separation and white turbidity were not observed in the measurement temperature region of the test. Further, in the table, "separation" means that phase separation or white turbidity has occurred at 20 °C.

(stability test)

In a 200 ml autoclave, 90 g of sample oil adjusted to 1000 ppm, 10 g of difluoromethane refrigerant, and Al, Cu, and Fe catalyst were heated at 175 ° C for 168 hours, and the acid after the end of the test was measured. value.

[Industrial availability]

According to the present invention, it is possible to provide a refrigerating machine oil which can achieve a high level of refrigerant compatibility, lubricity and low-temperature fluidity when used together with a difluoromethane refrigerant or an unsaturated fluorinated hydrocarbon, and the like. The freezer is used as a dynamic fluid composition.

Claims (13)

A refrigerating machine oil containing an ester obtained only from a polyhydric alcohol and a fatty acid, and the molar ratio of the fatty acid having 4 to 6 carbon atoms and the branched fatty acid having 7 to 9 carbon atoms in the above fatty acid is 15:85~ 90:10; the above-mentioned fatty acid having 4 to 6 carbon atoms contains 2-methylpropionic acid; and the total of the above-mentioned fatty acids having 4 to 6 carbon atoms and the above-mentioned branched fatty acids having 7 to 9 carbon atoms account for the fatty acid constituting the above ester The ratio of the total amount is 20 mol% or more. The refrigerating machine oil according to claim 1, wherein the ratio of the 2-methylpropionic acid to the fatty acid having 4 to 6 carbon atoms is 20 mol% or more. The refrigerating machine oil according to claim 1 or 2, wherein the fatty acid having 4 to 6 carbon atoms is 2-methylpropionic acid. The refrigerating machine oil according to claim 1 or 2, wherein the polyhydric alcohol is pentaerythritol, and the dynamic viscosity of the refrigerating machine oil at 40 ° C is 20 to 80 mm ² /s. The refrigerating machine oil according to claim 3, wherein the polyhydric alcohol is pentaerythritol, and the dynamic viscosity of the refrigerating machine oil at 40 ° C is 20 to 80 mm ² /s. The refrigerating machine oil according to claim 1 or 2, wherein the branched fatty acid having a carbon number of 7 to 9 is 3,5,5-trimethylhexanoic acid. The refrigerating machine oil of claim 3, wherein the branched fatty acid having a carbon number of 7 to 9 is 3,5,5-trimethylhexanoic acid. The refrigerating machine oil according to claim 4, wherein the branched fatty acid having a carbon number of 7 to 9 is 3,5,5-trimethylhexanoic acid. The refrigerating machine oil of claim 5, wherein the above-mentioned carbon number is 7-9 The acid is 3,5,5-trimethylhexanoic acid. A refrigerator is used as a dynamic fluid composition comprising the refrigerating machine oil according to any one of claims 1 to 9 and a difluoromethane refrigerant. A refrigerator is used as a dynamic fluid composition comprising the refrigerating machine oil of any one of claims 1 to 9 and an unsaturated fluorinated hydrocarbon refrigerant. A refrigerator is used as a dynamic fluid composition, comprising the refrigerating machine oil, the difluoromethane refrigerant, and the unsaturated fluorinated hydrocarbon refrigerant according to any one of claims 1 to 9. A refrigerating machine for use as a dynamic fluid composition, comprising the refrigerating machine oil according to any one of claims 1 to 9, a difluoromethane refrigerant, and an unsaturated fluorinated hydrocarbon refrigerant, and the above-mentioned difluoromethane refrigerant and the above unsaturated fluorinated hydrocarbon The mass ratio of refrigerant is 95:5~50:50.