JPH02182781A - Tetrafluoroethane-based composition for refrigerator - Google Patents

Abstract

PURPOSE:To obtain the subject composition having a high compatibility and capable of prevention of friction, abrasion, seizing, etc., at the sliding part of a compressor, etc., by blending a specified polyether with tetrafluoroethane. CONSTITUTION:The objective composition is composed of (A) a polyether [preferably polyether with 10-300cst kinetic viscosity (40 deg.C)] prepared by addition of an alkylene oxide to a halogen atomcontaining hydroxy compound (e.g. halogenated alcohol prepared by partly or more substituting H except those of hydroxyl group of alcohol such as methanol, ethylene glycol or glycerin with F, Cl, etc.) and (B) tetrafluoroethane.

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, car air conditioners, etc., B
-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 and paraffinic mineral oil cannot be used as the refrigerating machine oil for the tray 134a.

Polyether oils with the structure shown in Table 1 are known as substances that are relatively compatible with R-134a, for example,
Du Pont Research Disclosure
re (174830ct, 19781).

[Problem to be Solved by the Invention 1] 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. (71, (4) refrigerating machine oil is 1, for example, 40℃
When the kinematic viscosity at is 32.56 cst, the high temperature critical temperature is as shown in Table 1. The compatibility cannot be said to be sufficient.

Table 1 High temperature critical temperature of conventional polyether oil (compatibility with R-134a) (Umbrella) 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 made extensive efforts and discovered that a polyether obtained by adding an alkylene oxide to a hydroxy compound containing a halogen atom such as a fluorine atom The present invention was completed by discovering that it has excellent compatibility with tetrafluoroethane. That is, the present invention relates to a tetrafluoroethane-based refrigeration compound (compound m-acid) consisting of a boether and tetrafluoroethane obtained by adding an alkylene oxide to a hydroxy compound containing a halogen atom.

The hydroxy compound having a halogen atom in the present invention is not limited in any way as long as it is a compound that can be converted into a polyether by adding alkylene oxide, and various compound moieties can be employed.For example, methanol, ethanol, propatool, Aliphatic alcohols such as butanol, alicyclic alcohols such as cyclopentanol and cyclohexanol, or monohydric alcohols such as aromatic alcohols such as benzyl alcohol, or ethylene glycol, propylene glycol, butanediol, Cs+i
Alcohols such as dihydric alcohols such as alkanediols, or trihydric alcohols such as glycerin and trimethylolpropane, which have a small amount of hydrogen other than hydroxyl groups (both are halogenated alcohols partially substituted with fluorine or chlorine).

Also, halogenated phenols are m-phenols such as phenol and cresol, and polyhydric phenols such as hydroquinone, in which at least a portion of the hydrogen other than the hydroxyl groups is replaced with fluorine or chlorine.

Examples of the alkylene oxide to be added to the hydroxy compound containing a halogen atom 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. In the case of 2 fffi or more, it is preferable to use propylene oxide as the main component.

The polyether in the present invention has a kinematic viscosity of:
l(1~300cst (40℃), preferably 15~
It is desirable that the viscosity is 200cst (40°C), and the molecule m of polyether and the number of moles of alkylene oxide added to obtain the polyether are preferably selected such that the viscosity falls within this range. The number of moles added 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 contain a small amount of 1,1,2,2-tetrafluoroethane (RI34).

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, phosphine salts such as triphenoxyphosphine sulfide and trimethylphosphine sulfide, ruphide compounds, and other stabilizers such as glycidyl ethers may be added in small amounts. 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 It is possible to use it in combination with oil, fluorine-containing silicone oil, or polyether oil other than the polyether oil of the present invention.

Additionally, various additives such as phenol-based or amine-based antioxidants, sulfur- or phosphorus-based extreme pressure additives, silicone-based antifoaming agents, or metal deactivators such as benzotriazole may be added to the composition of the present invention. It may be further added.

[Example] Examples 1 to 5, Comparative Examples 1 to 5 The results of the polyether oil used in Examples 1 to 5 and Comparative Examples 1 to 5, compatibility with R-134a, and kinematic viscosity at 40 ° C. Shown in 2.

Table 2 [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 and the like.
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 hydroxy compound containing a halogen atom and tetrafluoroethane. 2. The kinematic viscosity of polyether is 10 to 300 cst (40
2. The tetrafluoroethane-based refrigerator composition according to claim 1, which is