JP5275578B2 - Refrigerator oil and working fluid composition for refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a freezer oil for hydrofluorocarbon refrigerants, which enable both of the reduction of a viscosity and the maintenance of a refrigerant-dissolved viscosity to be achieved, and to provide a hydraulic fluid composition for freezers. <P>SOLUTION: The freezer oil of the present invention for hydrofluorocarbon refrigerants contains an ester of a polyhydric alcohol containing 14 to 20C branched fatty acids of 40 to 100 mol%. The hydraulic fluid composition of the present invention for the freezers contains the ester of the polyhydric alcohol with the fatty acid containing the 14 to 20C branched fatty acids of 40 to 100 mol% and a hydrofluorocarbon refrigerant. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a refrigerating machine oil and a working fluid composition for a refrigerating machine used in a refrigerating and air-conditioning apparatus in which an HFC (hydrofluorocarbon) refrigerant is used.

  Due to the problem of ozone layer destruction in recent years, CFC (chlorofluorocarbon) and HCFC (hydrochlorofluorocarbon), which have been used as refrigerants in conventional refrigeration and air-conditioning equipment, are subject to regulation, and HFC (hydrofluorocarbon) as a refrigerant instead It is used.

On the other hand, in recent years, interest in energy conservation is increasing in various fields, and energy conservation measures such as improving thermal efficiency and reducing power consumption are also being studied in the field of refrigeration and air conditioning equipment. Therefore, in order to contribute from the refrigeration oil side in energy saving measures, techniques for improving energy efficiency by reducing the viscosity of the refrigeration oil have been proposed (see, for example, Patent Documents 1 and 2).
JP-A-10-204458 JP 2000-2977753 A

  However, refrigeration oil is used in the presence of a refrigerant, and the usage environment is significantly different from other lubricating oils used in an air atmosphere or the like. This is one of the reasons why the technology for reducing viscosity in other lubricating oil fields cannot be applied to refrigeration oil as it is. That is, from the viewpoint of improving energy efficiency, it is desirable that the kinematic viscosity of the refrigerating machine oil is low, but when the refrigerating machine oil is simply reduced in viscosity, the refrigerant is dissolved in the refrigerating machine oil in the refrigerating system so The viscosity (refrigerant dissolution viscosity) of the fluid composition, which is a mixture of the above, is greatly reduced, and there are concerns about problems such as blow-through and poor lubrication in the compression section of the refrigerant compressor.

  As described above, it is very difficult to achieve both a low viscosity of a refrigerating machine oil having a conflicting relationship and a sufficient refrigerant dissolution viscosity. In this regard, the conventional refrigerating machine oil for hydrofluorocarbon refrigerants has not been improved. There is room. Therefore, in the conventional refrigeration and air-conditioning equipment, it is the actual situation that only energy saving measures are taken by improving the mechanism of the refrigerant compressor to reduce the loss of the sliding part.

  The present invention has been made in view of such a situation, and an object of the present invention is a hydrofluorocarbon refrigerant refrigerating machine oil and a working fluid for a refrigerating machine capable of achieving both a low viscosity and a maintenance of a refrigerant dissolution viscosity. It is to provide a composition.

  As a result of intensive studies to achieve the above object, the present inventors have solved the above problems by using a fatty acid having a specific fatty acid composition as a constituent fatty acid of an ester and a polyhydric alcohol as a constituent alcohol. As a result, the present invention has been completed.

That is, the present invention is selected from fatty acids in which the proportion of branched fatty acids having 14 to 18 carbon atoms is 40 to 100 mol%, neopentyl glycol, trimethylolpropane, di-trimethylolpropane, pentaerythritol and di-pentaerythritol. A hydrofluorocarbon refrigerant refrigerating machine oil (hereinafter also referred to as “HFC refrigerant refrigerating machine oil”) characterized by containing an ester with at least one polyhydric alcohol (hereinafter also referred to as “ester according to the present invention”). .)I will provide a.

  Since the refrigerating machine oil for HFC refrigerant of the present invention has the above-described configuration, it is possible to achieve both reduction in viscosity and maintenance of sufficient refrigerant dissolution viscosity in the presence of the HFC refrigerant. Therefore, by using the refrigeration oil for HFC refrigerant of the present invention, the refrigerant gas sealability at the sliding portion of the refrigerant compressor, the lubricity at the sliding portion, and the energy efficiency of the refrigerant compressor are all achieved at a high level. As a result, it is possible to achieve both energy saving and high reliability of the refrigeration and air conditioning equipment.

  Moreover, the refrigerating machine oil for HFC refrigerant | coolants of this invention contains ester of the fatty acid whose ratio of C14-C20 branched fatty acid is 40-100 mol or more, and the polyhydric alcohol which has 2-6 hydroxyl groups. It is preferable. The polyhydric alcohol having 2 to 6 hydroxyl groups is selected from neopentyl glycol, trimethylolpropane, pentaerythritol, di- (trimethylolpropane), tri- (trimethylolpropane) and di- (pentaerythritol). It is preferable that it is 1 type or 2 types or more.

  Furthermore, the proportion of the branched fatty acid having 18 carbon atoms in the fatty acid constituting the ester according to the present invention is preferably 50 to 100 mol%.

Further, the present invention is selected from fatty acids in which the ratio of branched fatty acids having 14 to 18 carbon atoms is 40 to 100 mol%, neopentyl glycol, trimethylolpropane, di-trimethylolpropane, pentaerythritol and di-pentaerythritol. Provided is a working fluid composition for a refrigerator, comprising an ester with at least one polyhydric alcohol and a hydrofluorocarbon refrigerant.

  Since the working fluid composition for a refrigerator of the present invention contains the above-mentioned specific ester, it is possible to achieve both reduction in viscosity and maintenance of sufficient refrigerant dissolution viscosity in the presence of an HFC refrigerant. Therefore, by using the working fluid composition for a refrigerator according to the present invention, the refrigerant gas sealability in the sliding portion of the refrigerant compressor, the lubricity in the sliding portion, and the energy efficiency of the refrigerant compressor are all at a high level. As a result, it is possible to achieve both energy saving and high reliability of the refrigerating and air-conditioning equipment.

  As described above, according to the present invention, there are provided a hydrofluorocarbon refrigerant refrigerating machine oil and a working fluid composition for a refrigerating machine that can achieve both a reduction in viscosity and maintenance of refrigerant dissolution viscosity.

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

  The refrigerating machine oil for hydrofluorocarbon refrigerants of the present invention contains an ester of a fatty acid and a polyhydric alcohol in which the proportion of branched fatty acids having 14 to 20 carbon atoms is 40 to 100 mol%. Moreover, the working fluid composition for refrigerators of this invention contains the ester of the fatty acid and polyhydric alcohol whose ratio of C14-C20 branched fatty acid is 40-100 mol%, and a hydrofluorocarbon refrigerant. In addition, the aspect containing the refrigerating machine oil for hydrofluorocarbon refrigerants of this invention and the hydrofluorocarbon refrigerant is included in the working fluid composition for refrigerators of this invention.

  The proportion of the branched fatty acid having 14 to 20 carbon atoms in the fatty acid (hereinafter referred to as “constituent fatty acid”) constituting the ester according to the present invention is 40 to 100 mol%, preferably 50 to 100 mol as described above. %, More preferably 60 to 100 mol%. When the ratio of the branched fatty acid having 14 to 20 carbon atoms is less than 40 mol%, the lubricity in the presence of the HFC refrigerant becomes insufficient. Specific examples of the branched fatty acid having 14 to 20 carbon atoms include branched tetradecanoic acid, branched pentadecanoic acid, branched hexadecanoic acid, branched heptadecanoic acid, branched octadecanoic acid, and branched nonadecane. Acid, branched icosanoic acid, branched henicosanoic acid, branched docosanoic acid, branched hexadecanoic acid, branched heptadecanoic acid, branched octadecanoic acid are preferred, and branched octadecanoic acid is more preferred. preferable.

  Further, the constituent fatty acid may contain only the branched fatty acid as long as the ratio of the branched fatty acid having 14 to 20 carbon atoms satisfies the above conditions, or may be a mixture of the branched fatty acid and the linear fatty acid. Good. Furthermore, the constituent fatty acid may contain a branched fatty acid other than the branched fatty acid having 14 to 20 carbon atoms.

  Examples of fatty acids other than branched fatty acids having 14 to 20 carbon atoms include linear fatty acids having 6 to 24 carbon atoms, branched fatty acids having 6 to 13 carbon atoms and 21 to 24 carbon atoms, and more specifically, Linear or branched hexanoic acid, linear or branched heptanoic acid, linear or branched octanoic acid, linear or branched nonanoic acid, linear or branched decanoic acid, Linear or branched undecanoic acid, linear or branched dodecanoic acid, linear or branched tridecanoic acid, linear tetradecanoic acid, linear pentadecanoic acid, linear hexadecanoic acid, Linear heptadecanoic acid, linear octadecanoic acid, linear nonadecanoic acid, linear eicosanoic acid, linear or branched heicosanoic acid, linear or branched docosanoic acid, linear Or branched tricosanoic acid, linear It can be mentioned, such as branched tetracosanoic acid.

  Further, the carbon number distribution of the constituent fatty acid is not particularly limited as long as the ratio of the branched fatty acid having 14 to 20 carbon atoms satisfies the above conditions, but the viewpoint of suitably ensuring the fluidity and lubricity in the presence of the HFC refrigerant. From the above, the proportion of fatty acids having 16 to 18 carbon atoms (including both straight-chain fatty acids and branched fatty acids) is preferably 40 to 100 mol%, more preferably 50 to 100 mol%, still more preferably 60 to It is 100 mol%, more preferably 80 to 100 mol%, particularly preferably 90 to 100 mol%, and most preferably 95 to 100 mol%. When the proportion of the fatty acid having 16 to 18 carbon atoms is less than 40 mol%, the lubricity in the presence of the HFC refrigerant tends to be lowered. Moreover, when the ratio of a C16-C18 fatty acid is 40 mol% or more, an appropriate refrigerant melt viscosity cannot be maintained, and there is a concern about a decrease in energy efficiency.

  Furthermore, in the ester according to the present invention, the proportion of the branched fatty acid having 18 carbon atoms in the constituent fatty acid is 50 to 100 mol% from the viewpoint of suitably ensuring fluidity and lubricity in the presence of the HFC refrigerant. It is preferable that there is more preferably 60 to 100 mol%, still more preferably 70 to 100 mol%.

  Moreover, as a polyhydric alcohol which comprises the ester concerning this invention, the polyhydric alcohol which has 2-6 hydroxyl groups is used preferably. From the viewpoint of obtaining a high level of lubricity in the presence of an HFC refrigerant, it is preferable to use a polyhydric alcohol having 4 to 6 hydroxyl groups, and in view of obtaining a high level of energy efficiency in the presence of an HFC refrigerant. Is preferably a polyhydric alcohol having 2 or 3 hydroxyl groups.

  Specific examples of the dihydric alcohol (diol) include ethylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,2-butanediol, and 2-methyl-1,3-propane. Diol, 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-decanediol, 1,11-undecanediol, 1, Examples thereof include 12-dodecanediol. Specific examples of trihydric or higher alcohols include trimethylolethane, trimethylolpropane, trimethylolbutane, di- (trimethylolpropane), tri- (trimethylolpropane), pentaerythritol, di- ( Pentaerythritol), tri- (pentaerythritol), glycerin, polyglycerol (glycerin 2-3 trimer), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerol condensate, adonitol, arabitol, xylitol, mannitol And polyhydric alcohols such as xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, and cellobiose. Among these, hindered such as neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), pentaerythritol, di- (pentaerythritol), etc. Alcohol is preferred.

  Since the ester according to the present invention is more excellent in hydrolytic stability, neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), More preferred are hindered alcohol complete esters such as pentaerythritol, di- (pentaerythritol), tri- (pentaerythritol), neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane and pentaerythritol complete esters. Even more preferable, neopentyl glycol, trimethylolpropane and complete ester of pentaerythritol are particularly preferable, and particularly excellent in compatibility with the refrigerant and hydrolytic stability. Complete esters of Luo pentaerythritol is most preferred.

  The ester according to the present invention may be composed of one kind of ester having a single structure, or may be a mixture of two or more kinds of esters having different structures.

  The ester according to the present invention is an ester of one fatty acid and one polyhydric alcohol, an ester of two or more fatty acids and one polyhydric alcohol, one fatty acid and two or more polyhydric esters. Either a complete ester with a monohydric alcohol, an ester of two or more fatty acids and two or more polyhydric alcohols may be used. Among these, polyol esters using mixed fatty acids, particularly polyol esters composed of two or more fatty acids in a complete ester molecule, are excellent in low temperature characteristics and compatibility with refrigerants.

  In addition, the refrigerating machine oil for HFC refrigerant of the present invention is a polyhydric acid and a polyvalent fatty acid in which the ratio of the branched fatty acid having 14 to 20 carbon atoms is 40 to 100 mol%, as long as the excellent effect of the ester according to the present invention is not impaired. You may contain the partial ester with alcohol. Here, the partial ester means an ester in which a part of the hydroxyl acid of the polyhydric alcohol remains as a hydroxyl group without being esterified. The partial ester is also present as a by-product when the ester according to the present invention is synthesized. The purity of the ester according to the present invention obtained by synthesis is defined by the hydroxyl value of the synthesized product, the hydroxyl value is preferably 20 mgKOH / g or less, more preferably 10 mgKOH / g or less, and even more preferably 5 mgKOH / g or less.

  The refrigerating machine oil for HFC refrigerant of the present invention may consist only of the ester according to the present invention, but may further contain a base oil other than the ester according to the present invention. Examples of base oils other than esters according to the present invention include mineral oils, olefin polymers, naphthalene compounds, hydrocarbon oils such as alkylbenzenes, and ester base oils other than esters according to the present invention (monoesters, linear as constituent fatty acids) Polyol esters containing only fatty acids, etc.), synthetic oils containing oxygen such as polyglycols, polyvinyl ethers, ketones, polyphenyl ethers, silicones, polysiloxanes and perfluoroethers may be used in combination. Among the above, esters, polyglycols, and polyvinyl ethers are preferably used as the synthetic oil containing oxygen.

  In the refrigerating machine oil for HFC refrigerant of the present invention, the ester content according to the present invention is not particularly limited, but is superior in various performances such as energy efficiency, lubricity, refrigerant compatibility, thermal / chemical stability, and electrical insulation. From the total amount of refrigerating machine oil, it is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, still more preferably 40% by mass or more, and particularly preferably 50% by mass or more. Further, the ester content in the refrigerator oil for HFC refrigerant of the present invention is preferably selected so that the content of the ester according to the present invention based on the total amount of the refrigerator oil satisfies the above conditions.

  Moreover, the refrigerating machine oil for HFC refrigerants of the present invention can be used in a form in which various additives are blended as required.

  In order to further improve the wear resistance and load resistance of the refrigerating machine oil for HFC refrigerant of the present invention, phosphoric acid ester, acidic phosphoric acid ester, thiophosphoric acid ester, amine salt of acidic phosphoric acid ester, chlorinated phosphoric acid ester and At least one phosphorus compound selected from the group consisting of phosphites can be blended. These phosphorus compounds are esters of phosphoric acid or phosphorous acid with alkanols and polyether type alcohols or derivatives thereof.

  Specifically, for example, as phosphate ester, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, triundecyl phosphate, tridodecyl phosphate, tritridecyl Phosphate, tritetradecyl phosphate, tripentadecyl phosphate, trihexadecyl phosphate, triheptadecyl phosphate, trioctadecyl phosphate, trioleyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, xyl Examples include rhenyl diphenyl phosphate.

  Examples of acidic phosphate esters include monobutyl acid phosphate, monopentyl acid phosphate, monohexyl acid phosphate, monoheptyl acid phosphate, monooctyl acid phosphate, monononyl acid phosphate, monodecyl acid phosphate, monoundecyl acid phosphate, monododecyl Acid phosphate, monotridecyl acid phosphate, monotetradecyl acid phosphate, monopentadecyl acid phosphate, monohexadecyl acid phosphate, monoheptadecyl acid phosphate, monooctadecyl acid phosphate, monooleyl acid phosphate, dibutyl acid phosphate, dipentyl acid , Dihexyl reed Dophosphate, diheptyl acid phosphate, dioctyl acid phosphate, dinonyl acid phosphate, didecyl acid phosphate, diundecyl acid phosphate, didodecyl acid phosphate, ditridecyl acid phosphate, ditetradecyl acid phosphate, dipentadecyl acid, dipentadecyl acid Examples include hexadecyl acid phosphate, diheptadecyl acid phosphate, dioctadecyl acid phosphate, dioleyl acid phosphate, and the like.

  Examples of thiophosphates include tributyl phosphorothioate, tripentyl phosphorothionate, trihexyl phosphorothionate, triheptyl phosphorothionate, trioctyl phosphorothionate, trinonyl phosphorothionate, tridecyl phosphorothioate. Phorothionate, triundecyl phosphorothionate, tridodecyl phosphorothionate, tritridecyl phosphorothionate, tritetradecyl phosphorothionate, tripentadecyl phosphorothionate, trihexadecyl phosphorothionate, Triheptadecyl phosphorothioate, trioctadecyl phosphorothionate, trioleyl phosphorothionate, triphenyl phosphorothionate, tricresyl phosphorothionate, trixyl Cycloalkenyl phosphorothionate, cresyldiphenyl phosphorothionate, like carboxymethyl Les sulfonyl diphenyl phosphorothionate.

  Examples of the amine salt of acidic phosphate ester include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, Examples thereof include salts with amines such as dipentylamine, dihexylamine, diheptylamine, dioctylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine.

  Examples of the chlorinated phosphate ester include tris-dichloropropyl phosphate, tris-chloroethyl phosphate, tris-chlorophenyl phosphate, polyoxyalkylene bis [di (chloroalkyl)] phosphate, and the like. As phosphites, dibutyl phosphite, dipentyl phosphite, dihexyl phosphite, diheptyl phosphite, dioctyl phosphite, dinonyl phosphite, didecyl phosphite, diundecyl phosphite, didodecyl phosphite, dioleyl Phosphite, diphenyl phosphite, dicresyl phosphite, tributyl phosphite, tripentyl phosphite, trihexyl phosphite, triheptyl phosphite, trioctyl phosphite, trinonyl phosphite, tridecyl phosphite, triundecyl phosphite Phyto, tridodecyl phosphite, trioleyl phosphite, triphenyl phosphite, tricresyl phosphite and the like can be mentioned. Mixtures of these can also be used.

  When the refrigerating machine oil for HFC refrigerant of the present invention contains the phosphorus compound, the content of the phosphorus compound is not particularly limited, but 0.01% based on the total amount of refrigerating machine oil (based on the total amount of base oil and all blended additives). It is preferable that it is -5.0 mass%, and it is more preferable that it is 0.02-3.0 mass%. In addition, the said phosphorus compound may be used individually by 1 type, and may use 2 or more types together.

  In order to further improve the stability of the refrigerating machine oil for HFC refrigerant of the present invention, a phenyl glycidyl ether type epoxy compound, an alkyl glycidyl ether type epoxy compound, a glycidyl ester type epoxy compound, an allyl oxirane compound, an alkyl oxirane compound, It can contain at least one epoxy compound selected from alicyclic epoxy compounds, epoxidized fatty acid monoesters, and epoxidized vegetable oils.

  Specific examples of the phenyl glycidyl ether type epoxy compound include phenyl glycidyl ether and alkylphenyl glycidyl ether. As used herein, the alkylphenyl glycidyl ether includes those having 1 to 3 alkyl groups having 1 to 13 carbon atoms, and those having one alkyl group having 4 to 10 carbon atoms, such as n-butylphenyl glycidyl. Ether, i-butylphenyl glycidyl ether, sec-butylphenyl glycidyl ether, tert-butylphenyl glycidyl ether, pentylphenyl glycidyl ether, hexylphenyl glycidyl ether, heptylphenyl glycidyl ether, octylphenyl glycidyl ether, nonylphenyl glycidyl ether, decylphenyl A glycidyl ether etc. can be illustrated as a preferable thing.

  As the alkyl glycidyl ether type epoxy compound, specifically, decyl glycidyl ether, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, 2-ethylhexyl glycidyl ether, neopentyl glycol diglycidyl ether, Examples thereof include trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1,6-hexanediol diglycidyl ether, sorbitol polyglycidyl ether, polyalkylene glycol monoglycidyl ether, and polyalkylene glycol diglycidyl ether.

  Specific examples of the glycidyl ester type epoxy compound include phenyl glycidyl ester, alkyl glycidyl ester, alkenyl glycidyl ester, etc., and preferable ones are glycidyl-2,2-dimethyloctanoate, glycidyl benzoate, glycidyl acrylate. And glycidyl methacrylate.

  Specific examples of the allyloxirane compound include 1,2-epoxystyrene and alkyl-1,2-epoxystyrene.

  Specific examples of the alkyloxirane compound include 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-epoxyheptane, 1,2-epoxyoctane, 1,2- Epoxy nonane, 1,2-epoxydecane, 1,2-epoxyundecane, 1,2-epoxydodecane, 1,2-epoxytridecane, 1,2-epoxytetradecane, 1,2-epoxypentadecane, 1,2- Examples include epoxyhexadecane, 1,2-epoxyheptadecane, 1,1,2-epoxyoctadecane, 2-epoxynonadecane, 1,2-epoxyicosane and the like.

  Specific examples of the alicyclic epoxy compound include 1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and bis (3,4 -Epoxycyclohexylmethyl) adipate, exo-2,3-epoxynorbornane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 2- (7-oxabicyclo [4.1.0] hept-3- Yl) -spiro (1,3-dioxane-5,3 ′-[7] oxabicyclo [4.1.0] heptane, 4- (1′-methylepoxyethyl) -1,2-epoxy-2-methyl Examples include cyclohexane and 4-epoxyethyl-1,2-epoxycyclohexane.

  Specific examples of the epoxidized fatty acid monoester include esters of an epoxidized fatty acid having 12 to 20 carbon atoms with an alcohol or phenol having 1 to 8 carbon atoms or an alkylphenol. In particular, butyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl, phenyl and butylphenyl esters of epoxy stearate are 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, phenyl glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, alicyclic epoxy compounds and epoxidized fatty acid monoesters are preferred. Of these, phenyl glycidyl ether type epoxy compounds and glycidyl ester type epoxy compounds are more preferred, and phenyl glycidyl ether, butylphenyl glycidyl ether, alkyl glycidyl esters or mixtures thereof are particularly preferred.

  When the refrigerating machine oil for HFC refrigerant of the present invention contains the above epoxy compound, the content of the epoxy compound is not particularly limited, but is preferably 0.1 to 5.0% by mass based on the total amount of refrigerating machine oil. More preferably, it is 2 to 2.0% by mass. In addition, the said epoxy compound may be used individually by 1 type, and may use 2 or more types together.

  Furthermore, the refrigerating machine oil for HFC refrigerant of the present invention can contain conventionally known refrigerating machine oil additives as necessary in order to further enhance the performance. Examples of such additives include phenolic antioxidants such as di-tert-butyl-p-cresol and bisphenol A, phenyl-α-naphthylamine, N, N-di (2-naphthyl) -p-phenylenediamine, and the like. Amine-based antioxidants, anti-wear agents such as zinc dithiophosphate, extreme pressure agents such as chlorinated paraffin and sulfur compounds, oil-based agents such as fatty acids, antifoaming agents such as silicones, metal inertness such as benzotriazole Agents, viscosity index improvers, pour point depressants, detergent dispersants and the like. These additives may be used individually by 1 type, and may be used in combination of 2 or more type. The content of these additives is not particularly limited, but is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total amount of refrigerating machine oil.

The kinematic viscosity of the refrigerating machine oil for HFC refrigerant of the present invention is not particularly limited, but the kinematic viscosity at 40 ° C. is preferably 3 to 1000 mm ² / s, more preferably 4 to 500 mm ² / s, and most preferably 5 to 400 mm ^2. / S. The kinematic viscosity at 100 ° C. is preferably 1 to 100 mm ² / s, more preferably ² to 50 mm ² / s.

Further, the volume resistivity of the refrigerating machine oil for HFC refrigerant of the present invention is not particularly limited, but is preferably 1.0 × 10 ¹² Ω · cm or more, more preferably 1.0 × 10 ¹³ Ω · cm or more, most preferably It can be set to 1.0 × 10 ¹⁴ Ω · cm or more. In particular, when it is used for a hermetic refrigerator, high electrical insulation tends to be required. In the present invention, the volume resistivity means a value at 25 ° C. measured based on JIS C 2101 “Electrical insulating oil test method”.

  Further, the water content of the refrigeration oil for HFC refrigerant of the present invention is not particularly limited, but can be preferably 200 ppm or less, more preferably 100 ppm or less, and most preferably 50 ppm or less, based on the total amount of refrigeration oil. In particular, when it is used for a hermetic refrigerator, it is required to have a low water content from the viewpoint of the effect on oil stability and electrical insulation.

  Further, the acid value of the refrigerating machine oil for HFC refrigerant of the present invention is not particularly limited, but it is contained in the refrigerating machine oil for HFC refrigerant of the present invention in order to prevent corrosion to the metal used in the refrigerating machine or piping. In order to prevent decomposition of the ester oil, it is preferably 0.1 mgKOH / g or less, more preferably 0.05 mgKOH / g or less. In addition, in this invention, an acid value means the acid value measured based on JISK2501 "Petroleum products and lubricating oil-neutralization number test method".

  Further, the ash content of the refrigerating machine oil for HFC refrigerant of the present invention is not particularly limited, but in order to increase the stability of the refrigerating machine oil for HFC refrigerant of the present invention and suppress the generation of sludge, it is preferably 100 ppm or less, more preferably 50 ppm or less. It can be. In the present invention, ash means the value of ash measured based on JIS K 2272 “Testing method for ash and sulfated ash of crude oil and petroleum products”.

  The refrigerating machine oil for HFC refrigerant of the present invention exerts its excellent effect when used together with the HFC refrigerant, but the refrigerant used may be the HFC refrigerant alone or other HFC refrigerant and other It may be a mixed refrigerant with a refrigerant. Examples of other refrigerants include fluorine-containing ether refrigerants such as bar fluoroethers, hydrocarbons, carbon dioxide, dimethyl ether, and ammonia.

  HFC refrigerants include specific hydrofluorocarbons having 1 to 3 carbon atoms, preferably 1 to 2 carbon atoms. Specifically, for example, difluoromethane (HFC-32), trifluoromethane (HFC-23), pentafluoroethane (HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134), 1, Examples thereof include HFCs such as 1,1,2-tetrafluoroethane (HFC-134a) and 1,1,1-trifluoroethane (HFC-143a), and mixtures of two or more thereof. These refrigerants are appropriately selected depending on the application and required performance. For example, HFC-32 alone; HFC-23 alone; HFC-134a alone; HFC-125 alone; HFC-134a / HFC-32 = 60 to 80 mass % / 40-20 mass% mixture; HFC-32 / HFC-125 = 40-70 mass% / 60-30 mass% mixture; HFC-125 / HFC-143a = 40-60 mass% / 60-40 mass % Mixture; HFC-134a / HFC-32 / HFC-125 = 60 wt% / 30 wt% / 10 wt% mixture; HFC-134a / HFC-32 / HFC-125 = 40-70 wt% / 15- 35 mass% / 5 to 40 mass% mixture; HFC-125 / HFC-134a / HFC-143a = 35-55 mass% / 1-15 mass% / 40-60 mass Such as a mixture of preferred examples include. More specifically, a mixture of HFC-134a / HFC-32 = 70/30 mass%; a mixture of HFC-32 / HFC-125 = 60/40 mass%; HFC-32 / HFC-125 = 50/50 mass % Mixture (R410A); HFC-32 / HFC-125 = 45/55 wt% mixture (R410B); HFC-125 / HFC-143a = 50/50 wt% mixture (R507C); HFC-32 / HFC -125 / HFC-134a = 30/10/60 wt% mixture; HFC-32 / HFC-125 / HFC-134a = 23/25/52 wt% mixture (R407C); HFC-32 / HFC-125 / HFC-134a = 25/15/60 mass% mixture (R407E); HFC-125 / HFC-134a / HFC-143a = Mixtures of 4/4/52 wt% (R404A), and the like.

  Specific examples of the fluorinated ether refrigerant include HFE-134p, HFE-245mc, HFE-236mf, HFE-236me, HFE-338mcf, HFE-365mc-f, HFE-245mf, HFE-347mmy, HFE-347mcc. , HFE-125, HFE-143m, HFE-134m, HFE-227me and the like.

  As the hydrocarbon refrigerant, a gas refrigerant at 25 ° C. and 1 atm is preferably used. Specifically, it is an alkane, cycloalkane, alkene or a mixture thereof having 1 to 5 carbon atoms, preferably 1 to 4 carbon atoms. Specific examples include methane, ethylene, ethane, propylene, propane, cyclopropane, butane, isobutane, cyclobutane, methylcyclopropane, or a mixture of two or more thereof. Among these, propane, butane, isobutane or a mixture thereof is preferable.

  The mixing ratio of the HFC refrigerant and carbon dioxide, fluorine-containing ether refrigerant, dimethyl ether, and ammonia is not particularly limited, but the total amount of the refrigerant used in combination with the HFC refrigerant is preferably 1 to 200 mass with respect to 100 parts by mass of HFC. Part, more preferably 10 to 100 parts by mass. As a preferred embodiment, the HFC refrigerant and carbon dioxide and / or hydrocarbon are preferably 1 to 200 parts by mass, more preferably 10 to 100 parts by mass as the total amount of carbon dioxide and hydrocarbons with respect to 100 parts by mass of HFC. The mixed refrigerant which mix | blended is mentioned.

  The refrigeration oil for HFC refrigerant of the present invention is usually present in the form of a refrigeration fluid composition mixed with a refrigerant containing HFC as described above in refrigeration and air conditioning equipment. The blending ratio of the refrigerating machine oil and the refrigerant in this composition is not particularly limited, but the refrigerating machine oil is preferably 1 to 500 parts by mass, more preferably 2 to 400 parts by mass with respect to 100 parts by mass of the refrigerant.

  The refrigerating machine oil for HFC refrigerant and the working fluid composition for refrigerating machine of the present invention are applied to room air conditioners, packaged air conditioners and refrigerators having reciprocating or rotating hermetic compressors because of their excellent electrical characteristics and low moisture absorption. Preferably used. The HFC refrigerant refrigerating machine oil and the working fluid composition for the refrigerating machine of the present invention include automotive air conditioners, dehumidifiers, water heaters, freezers, refrigerated refrigerating warehouses, vending machines, showcases, chemical plant cooling devices, etc. Is preferably used. Furthermore, the refrigeration oil for HFC refrigerant and the working fluid composition for refrigeration according to the present invention are also preferably used for those having a centrifugal compressor.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[Composition of fatty acid A]
The composition of fatty acid A used in the following examples is shown in Table 1.

[Examples 1-13, Comparative Examples 1-14]
In Examples 1 to 13 and Comparative Examples 1 to 14, refrigerator oils were prepared using base oils 1 to 27 shown below. Various properties of the obtained refrigerating machine oil are shown in Tables 2 to 5.
(Base oil)
Base oil 1: ester base oil of fatty acid A and neopentyl glycol 2: mixed fatty acid of fatty acid A and n-decanoic acid (mixing ratio (mass ratio): fatty acid A / n-decanoic acid = 85/15) and neopentyl Ester base oil with glycol 3: mixed fatty acid of fatty acid A and 3,5,5-trimethylhexanoic acid (mixing ratio (mass ratio): fatty acid A / 3,5,5-trimethylhexanoic acid = 85/15) and neo Ester base oil with pentyl glycol 4: Ester base oil with fatty acid A and trimethylolpropane 5: Mixed fatty acid of fatty acid A and n-decanoic acid (mixing ratio (mass ratio): fatty acid A / n-decanoic acid = 85 / 15) Ester base oil of trimethylolpropane 6: mixed fatty acid of fatty acid A and 3,5,5-trimethylhexanoic acid (mixing ratio (mass ratio): fatty acid A / 3,5,5-trimethyl) Hexanoic acid = 85/15) and an ester of trimethylol propane)
Base oil 7: ester base oil of fatty acid A and di- (trimethylolpropane) 8: ester base oil of fatty acid A and pentaerythritol 9: ester base oil of fatty acid A and di- (pentaerythritol) 10: fatty acid Mixed fatty acid of A and n-decanoic acid (mixing ratio (mass ratio): fatty acid A / n-decanoic acid = 85/15) and ester base oil of pentaerythritol 11: fatty acid A and 3,5,5-trimethylhexane Mixed fatty acid of acid (mixing ratio (mass ratio): fatty acid A / 3,5,5-trimethylhexanoic acid = 85/15) and ester base oil of pentaerythritol 12: mixed fatty acid of fatty acid A and n-decanoic acid ( Mixing ratio (mass ratio): ester base oil of fatty acid A / n-decanoic acid = 70/30) and pentaerythritol 13: fatty acid A and 3,5,5-trimethylhexa Acid mixed fatty acid (mixing ratio (mass ratio): fatty acid A / 3,5,5-trimethylhexanoic acid = 70/30) and ester base oil of pentaerythritol 14: ester base oil of oleic acid and neopentyl glycol 15: mixed fatty acid of fatty acid A and n-decanoic acid (mixing ratio (mass ratio): fatty acid A / n-decanoic acid = 60/40) and ester base oil of neopentyl glycol 16: fatty acids A and 3, 5, Mixed fatty acid of 5-trimethylhexanoic acid (mixing ratio (mass ratio): fatty acid A / 3,5,5-trimethylhexanoic acid = 60/40) and neopentyl glycol ester base oil 17: oleic acid and trimethylolpropane Ester base oil 18: Fatty acid A and n-decanoic acid mixed fatty acid (mixing ratio (mass ratio): fatty acid A / n-decanoic acid = 60/40) and trimethyl Ester base oil 19 with fatty propane 19: Fatty acid A and 3,5,5-trimethylhexanoic acid mixed fatty acid (mixing ratio (mass ratio): fatty acid A / 3,5,5-trimethylhexanoic acid = 60/40) and tri Ester base oil 20 with methylolpropane: mixed fatty acid of 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid (mixing ratio: 2-ethylhexanoic acid / 3,5,5-trimethylhexanoic acid = 50/50 (Molar ratio)) and ester base oil of dipentaerythritol 21: ester base oil of oleic acid and pentaerythritol 22: ester base oil of stearic acid and pentaerythritol 23: mixed fatty acid of fatty acid A and n-decanoic acid (Mixing ratio (mass ratio): fatty acid A / n-decanoic acid = 60/40) and ester base oil of pentaerythritol 24: fat Mixed base fatty acid of acid A and n-decanoic acid (mixing ratio (mass ratio): fatty acid A / n-decanoic acid = 60/40) and di- (pentaerythritol) ester base oil 25: fatty acid A and 3, 5 , 5-Trimethylhexanoic acid mixed fatty acid (mixing ratio (mass ratio): fatty acid A / 3,5,5-trimethylhexanoic acid = 60/40) and pentaerythritol ester base oil 26: fatty acid A and 3,5 , 5-trimethylhexanoic acid mixed fatty acid (mixing ratio (mass ratio): fatty acid A / 3,5,5-trimethylhexanoic acid = 60/40) and di- (pentaerythritol) ester base oil 27: polypropylene glycol Monomethyl ether.

  In the base oil, the ester content of all esters based on the total amount of base oil is 95% by mass or more, and the hydroxyl value is 5 mgKOH / g or less.

  Next, the following evaluation tests were carried out for each of the refrigerating machine oils of Examples 1 to 13 and Comparative Examples 1 to 14.

(Lubricity)
Based on ASTM D 2670 “FALEX WEAR TEST”, the running-in operation was performed for 1 minute under a load of 150 lb under the condition of the temperature of the refrigerator oil of 100 ° C. Next, while blowing HFC-134a refrigerant 10 L / h, the test machine was operated for 2 hours under a load of 250 lb, and the amount of wear of the test journal (pin) after the test was measured. The obtained results are shown in Tables 2 to 5.

(Refrigerant melt viscosity)
The apparatus shown in FIG. 1 includes a pressure vessel 5 (stainless steel, internal volume: 200 ml) having a viscometer 1, a pressure gauge 2, a thermocouple 3, and a stirrer 4, and a constant temperature for controlling the temperature in the pressure vessel 5. A tank 6 and a sampling cylinder 8 provided with a valve and connected to the pressure vessel 5 through a flow path 7 are provided. The sampling cylinder 8 and the flow path 7 are detachable, and the sampling cylinder 8 has its weight measured after vacuum degassing or after weighing a mixture of HFC-134a refrigerant and refrigerating machine oil. It is possible to measure. The thermocouple 3 and the thermostatic chamber 6 are electrically connected to temperature control means (not shown), respectively, and sample oil (or a mixture of HFC-134a refrigerant and refrigerating machine oil) is transferred from the thermocouple 3 to the temperature control means. ) And a control signal is sent from the temperature control means to the thermostatic chamber 6 to control the temperature of the refrigerating machine oil or the mixture. Furthermore, the viscometer 1 is electrically connected to an information processing device (not shown), and measurement data relating to the viscosity of the liquid in the pressure vessel 5 is sent from the viscometer 1 to the information processing device, and a predetermined condition is obtained. It is possible to measure the viscosity below.

  In this test, first, 100 g of refrigerating machine oil was put in the pressure vessel 5 and the inside of the vessel was vacuum degassed. Then, the HFC-134a refrigerant was introduced, and the mixture of the HFC-134a refrigerant and the refrigerating machine oil was mixed with the stirrer 4. The mixture was adjusted to 0.7 MPa at 40 ° C. while stirring and removing the refrigerant. After stabilization, the viscosity of the mixture of HFC-134a refrigerant and refrigeration oil was measured. Tables 2 to 5 show the measurement results of the obtained refrigerant viscosity at 40 ° C.

(Thermal stability)
In an autoclave, 90 g of refrigerating machine oil, 10 g of HFC-134a refrigerant, and catalyst (iron, copper, and aluminum wires) were sealed, and then heated to 200 ° C. and held for 2 weeks. The total acid value of the refrigeration oil after 2 weeks was measured. The obtained results are shown in Tables 2 to 5.

(Electrical insulation)
Based on JIS-C-2101 “Electrical Insulating Oil Test Method”, volume resistivity of refrigerating machine oil at 25 ° C. was measured. The obtained results are shown in Tables 2 to 5.

  As is clear from the results shown in Tables 2 to 5, the refrigerating machine oils of Examples 1 to 13 have all the performances of lubricity, thermal stability, electrical insulation and kinematic viscosity when used together with the HFC refrigerant. It is clear that the balance is excellent. In particular, it can be seen that the refrigerating machine oils of Examples 1 to 13 are excellent in lubricity in the coexistence of the HFC refrigerant as compared with the refrigerating machine oil of the comparative example having the same kinematic viscosity. Further, it is suggested that the refrigerant has a high melt viscosity, is difficult to blow through in the compressor, and has high energy efficiency.

It is a schematic block diagram which shows the refrigerant | coolant melt viscosity measuring apparatus used in the Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Viscometer, 2 ... Pressure gauge, 3 ... Thermocouple, 4 ... Stirrer, 5 ... Pressure vessel, 6 ... Constant temperature bath, 7 ... Flow path, 8 ... Sampling cylinder.

Claims (2)

Fatty acid having a ratio of branched fatty acids having 14 to 18 carbon atoms of 40 to 100 mol% and at least one polyvalent selected from neopentyl glycol, trimethylolpropane, di-trimethylolpropane, pentaerythritol and di-pentaerythritol A refrigerating machine oil for a hydrofluorocarbon refrigerant, comprising an ester with alcohol. Fatty acid having a ratio of branched fatty acids having 14 to 18 carbon atoms of 40 to 100 mol% and at least one polyvalent selected from neopentyl glycol, trimethylolpropane, di-trimethylolpropane, pentaerythritol and di-pentaerythritol A working fluid composition for a refrigerator, comprising an ester with alcohol and a hydrofluorocarbon refrigerant.

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