JPH0381394A - Tetrafluoroethane-based refrigerator composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in functions such as abrasion, friction and anti-seizing properties at a sliding part of a compressor, etc., by mixing a specific compound with tetrafluoroethane. CONSTITUTION:The title composition is obtained by mixing one or more compounds of the given formula [wherein R<1> is alkylene; X<1-2> are each alkyl or aryl; Y<1> is 3C or a higher dicarboxylic acid residue; and l and m are each a positive number such that the kinematic viscosity may be 5-400cst (40 deg.C)] having 2 or more ester linkages in the molecular with tetrafluoroethane.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is directed to a refrigerant, tetrafluoroethane, preferably 1.1.1.2-tetrafluoroethane (R-134
+4 from -20℃ or lower temperature against al
The present invention relates to a composition for a refrigerator consisting of a polyether containing an ester bond and tetrafluoroethane that are compatible with each other in any proportion at temperatures of 0° C. or higher. [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 and paraffinic mineral oil cannot be used as refrigerating machine oil for R-134a. Polyether oils having the structures shown in Table 1 are known as substances that are relatively compatible with R-134a. For (a), for example, outont's Re5erc
hDisclosure(174830cit, 197
81. Regarding (b), for example, U,
Pat. No. 4,755°316.

[Problem to be solved by the invention]

However, the polyethers shown in Table 1 had 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, (41 refrigerating machine oil is, for example, 40
When the kinematic viscosity at °C is 100 cst, the high temperature critical temperature (see notes in Table 1) is as shown in Table 1. The compatibility cannot be said to be sufficient. Table 1 Conventional polyether oil and high temperature critical temperature (*) High temperature critical temperature: Weight ratio of oil and R-134a: 15:
Mix at 85 and seal. As the temperature is increased, the temperature at which turbidity or two-layer separation begins is called the high temperature critical temperature. The better the compatibility, the higher the high-temperature critical temperature. [Means for Solving the Problems] As a result of extensive research, the present inventors have discovered that the compatibility with R-134a can be improved by introducing an ester bond into the polyether chain. That is, the present invention is based on the following general formula % [wherein R1 is an alkylene group, Xl, X2 is an alkyl group or an aryl group, Y' is a dicarboxylic acid residue having 3 or more carbon atoms, and β1m is a kinematic viscosity of ■ is 5 to 40 units cst (40
℃), and may be the same or different. The present invention relates to a tetrafluoroethane-based refrigerating machine oil composition comprising at least one compound selected from the following and tetrafluoroethane. R' in the general formula is an alkylene group such as an ethylene group, a propylene group, a butylene group, a tetramethylene group, etc., and these may be used alone or together in a random or block form. Preferably, the main component is a propylene group. As x' and x'', alkyl groups such as methyl, ethyl, propyl, butyl, and 2-ethylhexyl groups, and aryl groups such as phenyl are preferable. Dicarboxylic acids include aliphatic acids such as malonic acid, succinic acid, glucuric acid, adipic acid, sebacic acid, speric acid, methylsuccinic acid, methyl adipic acid, maleic acid, fumaric acid, and itaconic acid. Dicarboxylic acid: Aromatic dicarboxylic acids such as phthalic acids, diphenyldicarboxylic acid, and diphenylmethanedicarboxylic acid; Alicyclic dicarboxylic acids that are hydrogenated products of the above aromatic dicarboxylic acids: and both ends of polyalkylene glycol with a molecular weight of 50 to 1000 A dicarboxylic acid in which a carboxyl group is introduced is preferable.
400cst (40℃), preferably 10-300c
st (40°C), and may be the same or different. The compound represented by the above general formula has a kinematic viscosity of 5 to 400 cst (40°C) in order to sufficiently achieve functions such as friction, wear and seizure prevention in sliding parts of compressors etc. as a refrigerating machine oil. , preferably lO~3
00 cstf40℃) is desirable.
The molecular weight in the general formula or f2. It is preferable that the value of m is selected such that the viscosity falls within this range. 12, the value of m is approximately 2 to 60, preferably 3 to 30, and may be the same or different. The weight ratio of the compound represented by the above general formula and R-134a is 1/99 to 99/l, preferably 5/95 to 60/l.
It is 40. R-134a may contain a small amount of 1.1.2.2-tetrafluoroethane (R-1341). The compound of general formula (1) can be used alone or as a mixture thereof. 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. 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 compounds such as phosphite, diisopropyl phosphite, and diphenyl phosphite; phosphine sulfide compounds such as triphenoxyphosphine sulfide and trimethylphosphine sulfide; terminals of phenyl glycidyl ethers and polyalkylene glycols are epoxidized. It is sufficient to add about 0.01 to 10% by weight of a stabilizer such as an epoxide compound.In addition, the compound represented by the general formula of the present invention and the conventionally used naphthenic mineral oil, paraffinic mineral oil, Alkylbenzene-based synthetic oil, poly-α-olefin-based synthetic oil, perfluoropolyether oil which is a fluorine-based lubricating 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. 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. [Function] Although the mechanism of compatibilization between the oil of the present invention and the refrigerant tetrafluoroethane is not necessarily clear, it is believed that a certain interaction between the carbonyl group of the ester bond and the tetrafluoroethane is involved. It is thought that the [Example] Examples 1 to 5, Comparative Examples 1 to 4 Structure of oil used in Examples 1 to 5 and Comparative Examples 1 to 4, R-
Table 2 shows the results of compatibility with 134a and kinematic viscosity at 40°C. 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. General formula (1) having at least two or more ester bonds in the molecule ▲ Numerical formulas, chemical formulas, tables, etc. ▼ [In the formula, R^1 is an alkylene group, X^1, X^2 is an alkyl group or an aryl group, Y^1 is a di-
Carboxylic acid residues, l, m have kinematic viscosity of (1) 5 to 400
cst (40°C), and may be the same or different. ] A tetrafluoroethane-based refrigerator composition comprising at least one compound represented by the following and tetrafluoroethane.