Compositions – Electrolytes for electrical devices
Patent
1989-09-08
1992-01-28
Howard, Jacqueline V.
Compositions
Electrolytes for electrical devices
252 68, C10M15502, C09K 500
Patent
active
050841963
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a lubricating oil composition for a Flon atmosphere, more specifically to a lubricating oil composition which has excellent stability in a Flon atmosphere as well as excellent anti-foaming properties.
BACKGROUND ART
Generally, for lubricating oil used as a refrigerator oil, a heat pump oil, etc., various properties are required, such as (1) suitable viscosity, (2) excellent low temperature characteristics (low pour point or low flock point, etc.), (3) good compatibility with a coolant, (4) excellent high temperature stability under a coolant atmosphere, (5) excellent lubricity, (6) excellent anti-foaming properties, and the like.
On the other hand, in recent years, the tendency of increasing high efficiency, a miniaturization and weight reduction have rapidly progressed in refrigerators, heat pumps, etc., and the reciprocating system in compressors has changed to the rotary system. Further, there is a tendency that the temperature of exhaust gas is rising due to loading of an inverter or recovery of exhaust heat by a heat pump. Therefore, it is strongly required of a refrigerator oil, etc. to have high temperature stability.
In a refrigerator or a heat pump, accompanying the change in load at starting or during operation of a compressor, the pressure in a crankcase rapidly reduces so that Flon as a coolant dissolved in an oil evaporates and foams to cause various problems. That is, when foaming is marked, the frothy oil is accompanied by coolant gas (Flon) to be absorbed into a cylinder of the compressor and the inside of the cylinder is temporarily flooded with a large amount of oil. As the result, there is a fear that a valve mechanism may be damaged according to a large impact force due to the liquid hammer phenomenon. In addition, since such a large amount of oils flow out, the inside of the compressor is lacking for oil so that it offers adverse effect to lubrication at the sliding portion of metals, etc. and there is a danger of seizure occuring.
From the situation as mentioned above, there has been a desire to provide excellent anti-foaming properties to lubricating oils to be used for refrigerators or heat pumps.
The present inventor has intensively studied to solve the problems of the above conventional refrigerator oils, etc., and to develop a lubricating oil with excellent stability and improved anti-foaming properties under a Flon atmosphere.
As a result, it has been found that the above problems can be solved by blending a high viscosity polysiloxane having an epoxy structure with a base oil of a lubricating oil within a predetermined range. The present invention has completed based on such a finding.
An object of the present invention is to provide a lubricating oil composition with excellent stability under a Flon atmosphere.
Also, another object of the present invention is to provide a lubricating oil composition with excellent anti-foaming properties.
DISCLOSURE OF INVENTION
That is, the present invention is to provide a lubricating oil composition for a Flon atmosphere which comprises 100 parts by weight of a base oil having a kinematic viscosity at 40.degree. C. of 5 to 500 cSt and 0.0001 to 1 part by weight of a polysiloxane having an epoxy structure and a kinematic viscosity at 25.degree. C. of 1000 cSt or higher.
In the lubricating oil composition of the present invention, as a base oil (a base oil of the lubricating oil), a mineral oil or a synthetic oil can be used singly or in combination. Also, regarding the properties of the base oil, in general, a kinematic viscosity at 40.degree. C. may be 5 to 500 cSt, preferably 10 to 300 cSt, and there is no particular limitation concerning the other properties. Here, if the kinematic viscosity is less than 5 cSt, such problems occur that an amount of oil consumption by evaporation becomes large, that an amount of circulating oil increases, and that the sealing properties are poor. As representative examples of mineral oils used as the base oil, there can be mentioned a distillate oil obtained
REFERENCES:
patent: 3219624 (1965-11-01), Cohen
patent: 3887487 (1975-06-01), Camp et al.
patent: 4185140 (1980-01-01), Strella et al.
patent: 4787991 (1988-11-01), Morozumi et al.
Howard Jacqueline V.
Idemitsu Kosan Company Limited
Johnson Jerry D.
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