JPS58103594A - Sulfur-containing lubricating oil employed in freon gas atmosphere - Google Patents

Abstract

PURPOSE:To provide the titled lubricating oil which has improved wear resistance and exhibits excellent lubricating performance under severe conditions without using any special extreme-pressure additive, etc., by using a specified synthetic lubricating oil or a mixture thereof with a mineral oil as a base oil and incorporating an organosulfur compd. CONSTITUTION:0.04wt% (in terms of sulfur) organosulfur compd. such as dibenzothiophene, n-dodecylsulfide or phenylmethyl sulfide is incorporated in a base oil obtd. by blending at least one member (A) selected from poly-alpha-olefins, polyisobutylene, polyalkylene glycols, polyol esters and dibasic acid esters with a mineral oil (B) in a weight ratio of A:B of 100:0-20:80. A lubricating oil having improved wear resistance and exhibiting excellent lubricating performance under severe conditions without using special extreme-pressure additive, etc. can be obtd. which is used in a freon gas atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a sulfur-containing material that has excellent heat resistance and abrasion resistance, shows little change in viscosity due to temperature changes, and has excellent performance in terms of solubility and solubility. Regarding lubricating oils, in detail, synthetic lubricating oils or mixtures of synthetic lubricating oils and mineral oils are used as base oils, and they contain at least α04 weight percent (wtlG) of certain organic sulfur compounds as sulfur content. This is a lubricating oil used in a chlorofluorocarbon atmosphere.

A typical example of lubricating oil used in a fluorocarbon atmosphere is compressor oil for refrigeration or heating (hereinafter referred to as refrigeration oil) that uses fluorocarbons as a heat medium. Specifically, small household refrigerators and air conditioners.

Examples include car air conditioners, commercial refrigerators, air conditioner managers for building air conditioning, and lubricating oils for fluorocarbon expansion turbine equipment in geothermal or seawater temperature difference power generation that uses fluorocarbons as a working medium.

The lubricating oil used in these facilities must exhibit a lubricating effect while constantly being in contact with fluorocarbons in the intercalary system while being disconnected from the air.

In the reciprocating type, the cylinder, piston, and bearing interlocking device are used; in the rotating type (rotary set), the cylinder, a-tor, and bearing; in the turbo type, the main bearing, thrust bearing, shaft sealing device,
Gears and speed increasers are the main lubrication points, and wear resistance is required for these parts. Recently, as these devices have become smaller in size and have higher performance, the conditions for producing fluorocarbons tend to become more thermally severe, and lubricating oils are also required to be thermally stable for a long period of time. Especially heat pump air conditioners that are used all seasons.

Like a car air conditioner, immediately after startup and during high-speed operation,
Lubricating oil for equipment that is used under severe conditions.

A lubricant that has thermal stability and a small viscosity change due to temperature changes is required. Low viscosity lubricating oil is also important for energy saving in equipment.

On the other hand, a decrease in wear resistance is unavoidable, and countermeasures are required. good.

70m long methane or ethane hydrocarbon substituted with fluorine and chlorine, general formula OkH101mlFn (k is 1 to
It is omniscient that it is an integer of 2, which satisfies 2+2=:l+IE14-111 and is represented by 12 sets of nFi integers). Furthermore, it is well known that fluorocarbons decompose under high-temperature conditions when lubricating oil and metal coexist, causing metal corrosion and deterioration of lubricating oil, resulting in sludge formation and increased viscosity. JP-A-52-s states that 60-80% of diester synthetic oil is mixed with mineral oil.
In the ayoy publication, the use of polybutene was disclosed in JP-A-185.
It is disclosed in Japanese Patent No. 1-71464.

As a technology to improve wear resistance using additives.

Adding phosphite ester α01-10- (@@
@5s-88oo7%Ko11),) Adding 101 to 5 wt% of lioleyl 7 phosphate (101-5 wt%), Tricresyl 7 os 7A),) Adding 9 phenyl phosphite (11) ~2.O
Addition of wt9G (Japanese Unexamined Patent Publication No. 55-27572) has been disclosed. However, the above phosphorus compounds
It has the disadvantage of causing hydrolysis in the presence of trace amounts of water. Further, types of general extreme pressure agents are described in the periodical publication "Lubrication", Vol. 20, No. g4, pp. 104-105 (1975) K. However, these are gear oil and turbine oil.

Hydraulic oil takes into consideration the extreme pressure effect of O in the presence of air, and extreme pressure in a fluorocarbon atmosphere.

There is no mention of wear resistance at all, and there is no mention of the organic sulfur compound used in the present invention having an effect of improving extreme pressure properties.

The present inventor has continued his research with the aim of developing a lubricating oil that solves the above-mentioned problems. 9. He discovered that contact action improves wear resistance and completed the present invention.

That is, the present invention comprises (a) at least one of polyolefin, polyisobutylene, polyoxyalkylene glycol, polyol ester, and dibasic acid ester and (b) mineral oil in a weight ratio of (a): (b). Ratio is 100:O
This relates to a lubricating oil used in a fluorocarbon atmosphere characterized by mixing the base oil in a ratio of 96 to 20:80 and containing an organic sulfur compound as a sulfur content (194wt96 or more). It is a lubricating oil with excellent physical stability, little change in viscosity due to temperature and humidity, and excellent wear resistance.

The content of the present invention will be explained in detail below.

The base oil used in the present invention is a synthetic lubricating oil.

Specifically, they are polyalpha-olefin, polyinobutylene, polyalkylene glycol, polyol ester, and dibasic acid ester. One or more of these 01 types can be used alone or in combination as a base oil. The above synthetic lubricating oil may be used in combination with mineral oil. A preferred mixing range of the two is a weight ratio of 100:0 to 20:80. Does this ratio improve heat resistance?

It is determined depending on the application from the viewpoints of pour point, viscosity index, and flock point. An appropriate amount of alkylbenzene may be mixed into the mixture to improve the solubility of chlorofluorocarbons.

While synthetic lubricating oils are more expensive than mineral oils, the upper limit of their mixing ratio with mineral oils is determined by the above-mentioned characteristics and their economic efficiency and performance. The polyolefin is a highly branched nonapolymer having as a basic structure, the viscosity at 40° C. is 15 to 81 degrees, depending on the degree of polymerization 1. (For example, ()ULF company 87nfluil■)
.

Polyisobutylene is a polymer obtained from butane butylene by low-temperature catalytic reaction, and is commercially available with different viscosities depending on the degree of polymerization.

(For example, NOF Polyvis■). The basic structure of polyalkylene glycol is 1 R, -0 + M0.

Or R, -0÷(mu0---○He→total 0mu+ioR,
(In both of the above formulas, R, and R- are an alkyl group having 1 to 24 carbon atoms.

m is 1-100. ! I is an integer of 1 to 500, Mu0 represents oxyalkylene, and Mu is a polymer having an alkylene group having 2 to 26 carbon atoms represented by -cnn, , -.

Polyol esters are neopentyl polyethers (neopentyl glycol, trimethytetrafluoropane, pentaerythritol) and nistyl with fatty acids or dibasic acids having a carbon number of 5 to 20, and dibasic acid esters (RI# R* is an alkyl group having 1 to 20 carbon atoms, n is 2
-6 integer).

These synthetic lubricating oils are compatible with fluorocarbons and have a high viscosity index even when fluorocarbons are dissolved, so when used over a wide temperature range from low to high temperatures,
Little change in viscosity.

The mineral oil used when mixing mineral oil with the synthetic lubricant may be refined by ordinary lubricating oil refining means.In the lubricating oil of the present invention, it is necessary to perform extreme desulfurization. There is no Hiro. This is because the organic sulfur compounds contained in mineral oil have the advantage of exhibiting wear resistance in a fluorocarbon atmosphere. The viscosity of the lubricating oil of the present invention is 5~
sOOasi (40°C).

In the lubricating oil of the present invention, an organic sulfur compound is added to the above lubricating base oil so that the sulfur content is α04 wt 91 or more. When mineral oil is used as a base oil, natural organic sulfur compounds contained in the mineral oil are also included, and the total amount of the two is at least α04 v+t%. The viscosity of the lubricating oil (40℃) is 28 cm, exceeding Stokes (cat) and α04 wt9! You can't get better, so
In the above viscosity range, α04 wt% - or more α5
A preferable range is below wtts. 2 at 40℃
II c8 in the following viscosity range.

A sulfur content that satisfies the formula 8≧−α012×(Vis)+138 exhibits more stable wear resistance. In the above formula, 8 is the sulfur content 0wt1 value.

vl- is the viscosity at 40°C in centistokes (OS
t ). The above formula was determined based on nine results obtained by investigating wear resistance using samples with different viscosities and sulfur contents.

At a low yellow content that does not satisfy the above formula, a phenomenon of multi-steering on the lubricated surface was observed. The line in Figure 1 shows the basis for establishing the relationship between the sulfur content and viscosity.

To adjust the sulfur content, use the general formula (1
), (1) or (■) by adding and dissolving one or more organic sulfur compounds selected from the group represented by (■) into the base oil, or
This can be done by mixing mineral oil containing sulfur with synthetic lubricating oil, or by using a combination of both.

General formula (iris) General formula (■) L 8 Rm General formula 伽) (RO-00,000H* @shikiday Compounds represented by the general formula (璽) are collectively called thiophene sulfur compounds, and mineral oil 1 coal The compounds represented by the general formula (■) are collectively called sulfide or thioether sulfur compounds, and they exist naturally in mineral oil or can be synthesized. Obtained by the above general formula (1), (1)
At least one sulfur compound selected from the evaluations expressed in (2)) is added to the base oil, but when using a mixed base oil of mineral oil and synthetic lubricating oil, the organic If the content of sulfur compounds is high, simply mixing the mineral oil will increase the sulfur content to more than αo a wt, and there is no need to distinguish between the sulfur compounds originally present in the mineral oil and the sulfur compounds added.

Samples of base oils with a viscosity in the range of 28 to 35 centistokes (@40°C) and base oils in the range of viscosity of 16 to 21 centistokes were used as synthetic lubricating oil alone or with the addition of minerals to change the sulfur content. 〉.

Figure 2 shows the results of examining the wear resistance under a fluorocarbon atmosphere.

It can be seen that the presence of sulfur content is effective in improving wear resistance. It can be seen from Table 1 that the lubricating oil of the present invention using a synthetic lubricating oil has a small viscosity change with respect to temperature changes during use.

Table 1 [.

As mentioned above, the lubricating oil of the present invention improves wear resistance and exhibits favorable lubrication performance under severe conditions without using special extreme pressure agents. The structure and effects of the present invention will be explained in detail below based on examples.

Polymyolefin (0 from Gal 7 company 8Y11TPLU)
) was used as a synthetic lubricating oil, and refined mineral oil was appropriately mixed with this to obtain a base oil. These properties are shown in Table 2.

Table 2 The abrasion resistance test was conducted using the testing machine and test conditions listed in Table 5.

The properties of the base oil obtained by mixing the polyα-olefin and refined mineral oil are as shown in Table 4. If these base oils contain more than the required amount of sulfur, use them as sample oils, and if the sulfur content is insufficient, add organic sulfur compounds and use them as sample oils.

Table 5 Using the polyα-olefin in Table 2 and the mixed base oil in Table 4, sample oil to which an organic sulfur compound was added as necessary was used.
A wear resistance test was conducted under the conditions shown in Table 3. The results are shown in Table 5.

Example 2 or mixed with refined mineral oil 1 or 2 shown in Table 2.

If necessary, add organic sulfur compounds to adjust the sulfur content and use it as a sample oil. Abrasion resistance was determined by the method used in Example 1. The results are shown in Table 6. POMU G: Sialkylene glycol in polio

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the basis for determining the sulfur content in the lubricating oil of the present invention. FIG. 2 shows the relationship between sulfur content and wear scars for two types with different viscosities. Patent applicant: Japan Mining Co., Ltd., patent attorney (7569) Keishi Namikawa

Claims (1)

[Claims] (S) (a) Polymer olefin, polyisobutylene. At least one of polyalkylene glycol, polyol ester, and dibasic acid ester. (b) Mineral oil at weight opening (,): (ratio of b> is 1
Mix the organic sulfur compound with the base oil in the range of 0:0 to 20:80 (1104% by weight as sulfur content)
A lubricating oil used in a 7A atmosphere, characterized by containing at least (wt) or more. (2) The relationship between the centistokes value of the viscosity (Vis'') of the lubricating oil at 40C and the weight (-cents value) of the sulfur content (♂) is (a) or (b) - (a) Vis is 2e centistokes or less If 8≧
-α012 X (Vis) + LIL38 (B)
Claim 8, Paragraph 1, which satisfies any of S≧104 when Vi- is more than 28 and less than 500 centistokes070
Lubricating oil used in a negative atmosphere. (2) The lubricating oil according to claim I8, item 1 or 2, wherein the organic sulfur compound is naturally present in mineral oil. (4) The organic sulfur compound contains one or more sulfur-containing α041 by adding one or more selected from the group represented by the general formula (1>, (■) or (-)) Lubricating oil according to the range 1 or 2. General formula 0) General formula (1) Rs -B -R# General formula (■) 0 11% formula %) φ) Sulfur content present in mineral oil One or more organic sulfur compounds selected from natural organic sulfur compounds and compounds represented by the general formula (I)-g) or (2)) described in claim (4). The lubricating oil according to claim 1 or 2, which is prepared by blending with a sulfur compound.