JPH0350297A - Tetrafluoroethane composition for use in refrigerator - Google Patents

Abstract

PURPOSE:To provide the title composition excellent in the function of preventing the abrasion, wear, seizure, etc., of the sliding parts of a refrigerator, etc., by mixing a tetrafluoroethane and a polyether prepared through the addition reaction of a 2C or lower monohydric alcohol with an alkylene oxide. CONSTITUTION:A polyether (A) prepared by the addition of an alkylene oxide (e.g ethylene oxide) onto a 2C or lower monohydric alcohol (e.g. methanol) is mixed with a tetrafluoroethane (B) (e.g. 1,1,1,2-tetrafluoroethane) to produce a composition for use in a refrigerator. As the component A, a polyether having a kinematic viscosity at 40 deg.C of 5-300cst is suitably used, and the examples include polyethers of formula I, formula II, etc. Because of the high compatibility of component A with component B, the composition thus obtained shows excellent lubricity and is suitably employed as a refrigerant in a refrigerating cycle.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides tetrafluoroethane, preferably 1,1,
The present invention relates to a tetrafluoroethane-based refrigerator composition comprising 1.2-tetrafluoroethane (R-134a) and a specific polyether.

[Conventional technology] In the refrigeration cycle of refrigerators and car air conditioners, R
-12 (dichlorodifluoromethane) has been used as a good refrigerant. However, R-12 can destroy the ozone layer in the stratosphere and have a negative impact on biological systems, so alternatives are being considered. R-134a is considered to be the most promising substitute for R-12;
Naphthenic mineral oil and paraffinic mineral oil, which are common refrigeration oils for R-12, are not compatible with R-134a. Therefore, naphthenic mineral oil,
Paraffinic mineral oil cannot be used.

Polyether oils with the structure shown in Table 1 are known as substances that are relatively compatible with R-134a, for example,
Du pant Research Disclosure
re (174830ct, 1978).

[Problems to be Solved by the Invention] However, such polyether oils have the following problems.

・Insufficient compatibility with R-134a - In order to demonstrate lubricity, which is the most important role of refrigeration oil, R-1
It is necessary to be compatible with R-134a and circulate within the system together with R-134a. The refrigerating machine oil in (7') and l) is, for example, 40°C.
If the kinematic viscosity at is 32 + 56 c s t,
The high temperature critical temperatures are as shown in Table 1. The compatibility cannot be said to be sufficient.

Table 1 High temperature critical temperature of conventional polyether oil (R-13
(Compatibility with R-134a) (v) High temperature critical temperature: Weight ratio of oil and R-134a: 15:
Mix at 85 and seal. As the temperature was increased, the temperature at which cloudiness or two-layer separation began was defined as the high temperature critical temperature. The better the compatibility, the higher the high-temperature critical temperature.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present inventors have made extensive efforts, and as a result, the polyether obtained by adding alkylene oxide to a monohydric alcohol having 2 or less carbon atoms is tetrafluorocarbon. They found that it has excellent compatibility with ethane and completed the present invention. That is, the present invention relates to a tetrafluoroethane-based refrigerator composition comprising tetrafluoroethane and a polyether obtained by adding an alkylene oxide to a monohydric alcohol having 2 or less carbon atoms.

Examples of the monohydric alcohol having 2 or less carbon atoms in the present invention include methanol and ethanol.

Examples of the alkylene oxide to be added to the monohydric alcohol having 2 or less carbon atoms include ethylene oxide, propylene oxide, butylene oxide, and tetramethylene oxide. These alkylene oxides may be added singly, or at least two of these may be added randomly or in blocks. When two or more types are used, it is preferable that propylene oxide is used as the main ingredient.

The polyether in the present invention has a kinematic viscosity of:
5-300 cst (40°C), preferably lO-20
It is preferable that the molecular weight of the polyether and the number of moles of alkylene oxide added to obtain the polyether be selected such that the viscosity is within this range. The number of additional threads is 3 to 60, preferably 6 to 30.

The weight ratio of polyether and R134a in the present invention is 1
/99 to 99/l, preferably 5/95 to 60/40. R134a may be supported by a small amount of 1,1,2,2-tetrafluoroethane (R134).

The composition of the present invention is particularly effective in refrigeration cycle applications for freezing, refrigeration, and air conditioning in the low to high temperature fields, but can also be used in various other heat recovery technologies such as Rankine cycles. be.

The composition of the present invention has excellent thermal stability and does not require a stabilizer under normal usage conditions, but when it is necessary to improve thermal stability due to harsh usage conditions, dimethyl phosphite , phosphite compounds such as diisopropyl phosphite and diphenyl phosphite, phosphate compounds such as tricresyl phosphate, triphenyl phosphate and butyl dicresyl phosphate, phosphine sulfide compounds such as triphenoxyphosphine sulfide and trimedelphosphine sulfide. A small amount of other stabilizers such as glycidyl ethers may be added. Furthermore, the specific polyether oil of the present invention and conventionally used naphthenic mineral oils, paraffinic mineral oils, alkylbenzene-based synthetic oils, poly-α-olefin-based synthetic oils, and perfluoropolyethers that are fluorine-based lubricating oils oil,
It is possible to use it in combination with a fluorine-containing silicone oil or a polyether oil other than the polyether oil of the present invention.

In addition, amine-based and phenolic antioxidants such as 2,6-di-t-butyl-p-cresol, sulfur and phosphorus-based extreme pressure additives, silicone-based antifoaming agents, and metal inerts such as benzotriazole. Various additives such as agents may be further added to the composition of the present invention.

[Example] Examples 1 to 6, Comparative Examples 1 to 2 The results of the polyether oil used in Examples 1 to 6 and Comparative Examples 1 to 2, compatibility with R-134a, and kinematic viscosity at 40 ° C. Shown in 2.

Table [Effects of the Invention] The composition of the present invention has high compatibility between tetrafluoroethane and polyether oil, and reduces friction in sliding parts of compressors etc.
Functions such as wear and seizure prevention can be fully demonstrated.

Claims (1)

[Claims] 1. A tetrafluoroethane-based refrigerator composition comprising a polyether obtained by adding an alkylene oxide to a monohydric alcohol having 2 or less carbon atoms and tetrafluoroethane. 2. The kinematic viscosity of polyether is 5 to 300cst (40℃
) The tetrafluoroethane-based refrigerator composition according to claim 1.