Compositions – Vaporization – or expansion – refrigeration or heat or energy... – With lubricants – or warning – stabilizing or anti-corrosion...
Patent
1996-08-16
1998-09-08
Diamond, Alan
Compositions
Vaporization, or expansion, refrigeration or heat or energy...
With lubricants, or warning, stabilizing or anti-corrosion...
C09K 504
Patent
active
058040960
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to refrigerating machine oils which are used in refrigerating machines using a non-chlorine, fluorine-containing refrigerant, and which are excellent in hydrolytic stability and insulating properties and particularly superior in properties for use in large-sized air conditioning equipment, room air conditioners and refrigerators.
BACKGROUND ART
In refrigerating machines, chlorine-containing refrigerants, e.g., R11 (CCl.sub.3 F), R12 (CCl.sub.2 F.sub.2), R123 (CF.sub.3 CHCl.sub.2), R22 (CHClF.sub.2), etc., have heretofore been used as refrigerants. However, development of substitutional Freons has become a matter of great urgency from the environmental point of view, and attention has recently been paid to non-chlorine, fluorine-containing refrigerants, e.g., 1,1,1,2-tetrafluoro ethane (R134a) and so forth. Consequently, it has been proposed to employ ester oils, which are excellent in both compatibility with R134a and thermal stability, as refrigerating machine oils from the viewpoint of compatibility with R134a and also from the viewpoint of thermal stability required for refrigerating machine oils as a result of the recent achievement of high efficiency of refrigerating machines.
However, a refrigerating machine oil used in a refrigerating machine, for example, for a refrigerator having a hermetic compressor with a motor immersed in the refrigerating machine oil is required to have a volume resistivity of 1.times.10.sup.13 .OMEGA.-cm (25.degree. C.) or higher in general (in the state of being mixed with additives) because there is a danger of electrical leakage if the electrical insulating properties are low. In this regard, conventional refrigerating machine oils for chlorine-containing refrigerants involve no particular problem because these oils use a base oil having a relatively high volume resistivity oil, alkylbenzene, etc. However, commercially available ester oils, which are compatible with non-chlorine, fluorine-containing refrigerants, generally have a volume resistivity in the range of from 1.times.10.sup.11 .OMEGA.-cm to 1.times.10.sup.13 .OMEGA.-cm (25.degree. C.). Particularly, high-viscosity ester oils whose viscosity is about 70 mm.sup.2 /s at 40.degree. C. have a volume resistivity as low as 1.times.10.sup.12 .OMEGA.-cm (25.degree. C.). Therefore, such ester oils give rise to a problem when used as refrigerating machine oils with non-chlorine, fluorine-containing refrigerants substituted for chlorine-containing refrigerants, as described above.
Japanese Patent Application Laid-Open (KOKAI) No. 4-72390 (1992), for example, discloses a refrigerating machine oil using a hindered polyol ester oil having a specific group as an ester oil compatible with non-chlorine, fluorine-containing refrigerants, e.g., R134a. Further, pentaerythritol esters have been put to practical use as refrigerating machine oils for electric refrigerators. However, the viscosity of these ester oils is as low as 32 mm.sup.2 /s at 40.degree. C. Therefore, these ester oils cannot suitably be used as refrigerating machine oils for large-sized air conditioning equipment or room air conditioners, which require a high-viscosity ester oil having a viscosity of 68 mm.sup.2 /s or higher at 40.degree. C., for example. Among the ester oils, an ester of pentaerythritol and 3,5,5-trimethylhexanoic acid makes it possible to maintain compatibility with non-chlorine, fluorine-containing refrigerants and electrical insulating properties and to achieve high viscosity. However, it has become clear that the above-described ester crystallizes at low temperature and involves a problem in terms of handleability.
A first object of the present invention is to provide a refrigerating machine oil for use in refrigerating machines using non-chlorine, fluorine-containing refrigerants, e.g., R134a, which is particularly excellent in insulating properties and hydrolytic stability.
A second object of the present invention is to provide a refrigerating machine oil for use in refrigerating machines usin
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patent: 5294356 (1994-03-01), Tanaka et al.
patent: 5374366 (1994-12-01), Nakahara et al.
patent: 5395544 (1995-03-01), Hagihara et al.
patent: 5403503 (1995-04-01), Seiki et al.
Kuribayashi Toshiaki
Ogano Satoshi
Sato Takehisa
Diamond Alan
Jordan Richard D.
Tonen Corporation
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