JPH0436387A - Lubricant oil composition for refrigerator - Google Patents

Abstract

PURPOSE:To prepare a lubricant oil compsn. not corroding apparatuses, freed from drop in lubricant performances and good in low temp. characteristics by adding a fluorine-contg. polysiloxane having an epoxy structure to a lubricant oil base. CONSTITUTION:A lubricant oil compsn. is prepd. by adding 0.00001-10pts.wt. fluorine-contg. polysiloxane having an epoxy structure to 100pts.wt. lubricant oil used in refrigerators. The base oil may be a mineral oil, a synthetic oil or their mixture. As the base oil, a polyalkylene glycol or a fluorosilicone oil is pref. because of their high miscibility with a refrigerant (1,1,1,2- tetrafluorethane). As the polysiloxane, fluorine-contg, polysiloxane of the formula (Rf is perfluoralkyl; R1 is an epoxy-contg, group or CH3; n>=1; m>=0) is pref.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to lubricating oil for refrigerators.

[Prior art] Conventionally, naphthenic mineral oil, paraffinic mineral oil, alkylbenzene synthetic oil, and poly-α are used as lubricating oils for refrigerators.
-Olefin-based synthetic oils are known and are used to prevent friction, wear, and seizure in compressor sliding parts.

The characteristics required for lubricating oil for refrigerators include, unlike general lubricating oils, it must have excellent stability against refrigerants because it comes into contact with fluorocarbons as a refrigerant, and it must have excellent solubility with refrigerants. Examples include not dissolving polymeric materials such as packing used as raw materials.

Dichlorodifluoromethane (hereinafter referred to as R12), which has been conventionally used as a refrigerant, does not meet the above requirements for naphthenic mineral oil, paraffin mineral oil, alkylbenzene synthetic oil, poly-α-olefin synthetic oil, etc. It satisfies the conditions and can be used without any problems. However, it has been pointed out that R12 destroys the ozone layer and has a serious negative impact on the environment, and 1,1,1,2-tetrafluoroethane (hereinafter referred to as R13) has been proposed as a new refrigerant to replace it.
4a) has been proposed. However, R
134a includes conventionally used naphthenic mineral oil, paraffinic mineral oil, alkylbenzene synthetic oil, poly-
α-olefin synthetic oil etc. cannot be used because it does not dissolve.

To solve this problem, the use of polyalkylene glycol-based oils as lubricants is proposed in USP 4,755.
, 316, etc., is proposed in Japanese Patent Application No. 1-122947. These lubricating oils dissolve well in R134a and solve the above-mentioned problems, but during use, trace amounts of acid derived from R134a are generated, which can lead to equipment corrosion and a decline in lubrication performance. (I understand.

[Problems to be Solved by the Invention] The present invention has been made in order to eliminate the drawbacks of the prior art described above, and it satisfies the basic conditions required for a lubricant for refrigerators, and contains a trace amount of acid derived from R134a. The purpose of the present invention is to provide a lubricating oil composition in a fluorocarbon atmosphere that does not cause corrosion of equipment or deterioration of lubrication performance.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems,
Lubricating oil used in refrigerators: 0.000 parts by weight of fluorine-containing polysiloxane with an epoxy structure.
The present invention provides a lubricating oil composition for a refrigerator, characterized in that the lubricating oil composition is blended in a proportion of 1 to 10 parts by weight.

In the lubricating oil composition of the present invention, the base oil (1mif oil base oil) is not particularly limited, and mineral oils and synthetic oils may be used alone or in a mixture of both. However, R1
From the viewpoint of solubility in 34a, it is desirable to use polyalkylene glycol oil or fluorosilicone oil.

Next, in the lubricating oil composition of the present invention, it is necessary to blend a fluorine-containing polysiloxane having an epoxy structure into the base oil. There are various types of this product, but usually, in the following formula L, Rt is a perfluoroalkyl group,
Examples include fluorine-containing polysiloxanes in which R2 is Ep or CH, E is a group having an epoxy group, n and 1 are integers of 1 or more, and m is an integer of 0 or more. Here, the chain length and amount of R1 to be introduced may be determined within a range that ensures solubility in R134a, but in general, it is difficult to ensure solubility with perfluoroalkyl groups having 3 or less carbon atoms; It is preferable to use the above perfluoroalkyl groups.

E represents a group having an epoxy structure, specifically, glycidoxymethyl group, β-glycidoxyethyl group, γ-glycidoxyprobyl group, δ-glycidoxybutyl group , β-(3,4-epoxycyclohexyl)
Examples include ethyl group and β-(3,4-epoxyphenyl)ethyl group.

n, m, and 1 may be integers that satisfy the above formula, but since lubricants for R134a are normally used with a viscosity of 1 to 10 cst at 100°C, they must satisfy that condition. It is preferable to select nm of 1 so that the epoxy value is 0. O1~
0.5 gram equivalent/100g especially 0.02-0.4
It is best to select 1 so that the gram equivalent/100g is obtained. If the epoxy value is less than this, the acid content scavenging effect will be insufficient, and on the other hand, if more epoxy groups are introduced, the solubility will decrease and various problems will occur.

In the lubricating oil composition of the present invention, 0.0001 to 10 parts by weight, preferably 0.0001 to 10 parts by weight, preferably 0.
．． 0.001 to 0.1 part by weight. If the amount is less than this, the effect of trapping the acid content will not be sufficient, and if the amount is more than this, problems such as deterioration of electrical properties will occur.

The lubricating oil composition of the present invention is composed of a base oil and a fluorine-containing polysiloxane having an epoxy structure as described above, and may further contain various additives such as antioxidants, extreme pressure agents, Oily agents, copper deactivators, etc. can also be blended.

Here, the antioxidant is 2,6-di-t-butyl-
p-cresol; 2,6-di-t-butyl-p-ethylphenol; 4,4-methylenebis-(2,6-di-t-butyl-p-ethylphenol;
-butylphenol), and amine antioxidants such as phenyl-α-naphthylamine; octylated-phenyl-α-naphthylamine; mono-octylated diphenylamine; and di-octylated diphenylamine.

In addition, extreme pressure agents include phosphorus-based extreme pressure agents and sulfur-based extreme pressure agents, among which phosphorus-based extreme pressure agents are phosphate-based agents such as triphenyl phosphate, tricresyl phosphite, and tri(isopropyl). Examples include phenyl) phosphate, tributyl phosphate, trioctyl phosphate, triphenylthiophosphate, tricresyl thiophosphate, etc. Phosphite-based compounds include triphenyl phosphite, tricresyl phosphite, tri(nonylphenyl) ) phosphite, trilaurel phosphite, tristearyl phosphite, and tricresyl phosphite. Further, specific examples of the sulfur-based extreme pressure agent include di-laurylthiopropionate, ditridecylthiodipropionate, distearylthiodibutylobionate, thiophene, benzothiophene, dodecyl sulfide, and stearyl mercaptan.

Furthermore, oil-based agents include di(2-ethylhexyl) sebacate and di(2-ethylhexyl) azelate, and copper deactivators include benzotriazole, methylbenzotriazole, dimethylbenzotriazole, and mercaptobenzothiazole. can give.

[Function] The lubricating composition for a refrigerator of the present invention contains a fluorine-containing polysiloxane having an epoxy group. Here, the epoxy group captures trace amounts of acid derived from R134a, and prevents corrosion of equipment, deterioration of lubrication performance, etc. On the other hand, since it contains fluorine, it does not impair solubility in R134a, and since it has a siloxane skeleton, it also has good low-temperature properties.

[Example] Regarding the lubricating oil composition obtained by blending the base oil shown in Table 1 with a fluorine-containing polysiloxane having an epoxy structure shown in Table 2 at a predetermined ratio to prepare a lubricating oil composition. A shield tube test was conducted. The results are shown in Table 3.

The shield tube test was conducted as follows. That is, the internal volume containing steel, copper and aluminum wires is 10
2 ml of sample oil was poured into a 1.0 ml glass pressure-resistant ampoule using a syringe, and the sample was degassed.

After adding 5 g of refrigerant R134a while cooling with liquid nitrogen, it was sealed with a burner. 1 of these sealed ampoules
It was left in an oil bath at 75°C for 480 hours.

After the test, the ampoule was cooled with liquid nitrogen and opened, the unsealed end was absorbed into about 100 ml of distilled water, and the amount of hydrochloric acid generated was determined by titration with 0.1N potassium water sulfide solution. Calculated. In addition, the solubility of the lubricating oil composition in R134a was also observed.

Table 1 Table 2 *2 Shin-Etsu Chemical Co., Ltd. X-60-164 (product name) *
3 KF-96 (trade name) manufactured by Shin-Etsu Chemical ■4 Ebiol P (trade name) manufactured by Nippon Oil & Fats ■Table 3 *Units are ■-KOH/lnl [Effects of the invention] As explained above, the present invention The lubricating oil composition has excellent high temperature stability in the presence of various refrigerants such as fluorocarbons, and has R1
34a.

Claims (1)

[Claims] (1) Add 0.0 parts of fluorine-containing polysiloxane having an epoxy structure to 100 parts by weight of lubricating oil used in the refrigerator.
A lubricating oil composition for a refrigerator, characterized in that the lubricating oil composition is blended in a proportion of 0001 to 10 parts by weight.