JPH0657276A - Lubricant - Google Patents

Abstract

PURPOSE:To provide a lubricant which contains, as the base oil, a synthetic polyolefin-oligomer-based oil excellent in foam characteristics expressed by foaming and/or defoaming characteristics. CONSTITUTION:A lubricant which contains, as the base oil, a synthetic polyolefin-oligomer-based oil which has been subjected to an adsorption treatment by bringing in into contact with a solid acidic adsorbent. The lubricant may contain a fluorinated silicone oil in addition to the oligomer-based oil. The lubricant, excellent in foam characteristics expressed by foaming and/or defoaming characteristics, is suitable for lubricating an industrial machine where a lubricant is often recycled. The lubricant not only reduce the size of a lubricant recycling system but also extends the lives of a lubricated machine and the lubricant itself.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil, and more particularly to a lubricating oil composition used for bearings, hydraulics, gears, chains, engines, automatic transmissions, etc. of industrial machines.

[0002]

2. Description of the Related Art Generally, bearings, hydraulics, gears,
Lubricating oils used for chains and the like are continuously used or are used under heating conditions, and thus they are often used in circulation. That is, the lubricating oil used to lubricate the bearing and the like is usually subjected to treatments such as cooling and filtration, and then returned to the tank, allowed to stand still, and used again to lubricate the bearing and the like. In recent years, along with the miniaturization of machines, the tank capacity is also miniaturized, and the retention time of lubricating oil is often small, such as several minutes or less. Since the lubricating oil that enters the tank bites air in the lubrication section, foaming is unavoidable, and in some cases, this foam may remain without disappearing during retention in the tank. Then, the stored lubricating oil is sucked by an oil supply pump and sent to a predetermined lubrication portion.In this case, if a lot of bubbles are present, cavitation occurs or a mixture of oil and air is supplied to the lubrication surface. As a result, the oil film may run out. As a result, this leads to shortening of the mechanical life, so there is a demand for a lubricating oil with less foaming, faster foam disappearance, or better air release, that is, a so-called better foaming property. Polyolefin synthetic oils are used for various lubrications because they are excellent in heat resistance, cold resistance, shear stability, etc., but also for this reason, improvement of foam characteristics is required for the above reasons. In order to improve the defoaming property, a method of blending a silicone oil, a polyacrylate, a perfluoroether or the like with a lubricating base oil is also known (JP-A-3-126,
No. 790) and a polyolefin-based synthetic oil are not sufficiently effective.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polyolefin-based synthetic oil-based lubricating oil having excellent antifoaming properties, foam eliminating properties or air releasing properties.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a lubricating oil comprising a polyolefin oligomer-based synthetic oil as a lubricating base oil, wherein the polyolefin oligomer-based synthetic oil is brought into contact with an acidic solid adsorbent for adsorption treatment. Another aspect of the present invention is a lubricating oil containing a polyolefin oligomer-based synthetic oil as a lubricating base oil and a fluorinated silicone oil. Lubricating oil.

The lubricating base oil used in the present invention is a polyolefin oligomer-based synthetic oil, preferably α
-Olefin oligomer, ethylene-α-olefin oligomer and the like. The olefin preferably has 2 to 20 carbon atoms, and specific examples thereof include 1-decene trimer to hexamer and ethylene-α-olefin copolymer. The lubricating base oil may be a mixture of various polyolefin oligomer-based synthetic oils.

If this polyolefin oligomer-based synthetic oil is used as it is as a lubricating base oil, it becomes difficult to meet the strict requirements regarding the foam characteristics as described above. Therefore, the present invention improves this point by subjecting this to adsorption treatment under specific conditions. The adsorbent used in the adsorption treatment is an acidic solid adsorbent, and is a so-called solid acid such as activated clay, silica gel, alumina gel, or zeolite. Other adsorbents,
For example, activated carbon has almost no effect. This adsorption treatment can be carried out by bringing it into contact with an adsorbent, but a preferable example is under heating conditions, for example, 50 to 150 ° C.
Then, 1 to 5% by weight of the powdery adsorbent with respect to the synthetic oil is used, the mixture is stirred for 0.5 to 3 hours, and then the adsorbent is separated to obtain a lubricating base oil.

By the way, by such an adsorption treatment, the foaming property, particularly the air release property is improved, but the foaming preventing property is not so improved. However, in general, even if the air release property is inferior, it can be said that the foaming property as a whole is excellent if the foaming preventing property and the foam extinguishing property are excellent, and the object of the present invention is also improved by improving the foaming preventing property. It can be said that it can be achieved. Further, it can be said that it is more desirable if the foaming-preventing property as well as the air-releasing property can be improved. Therefore, another aspect of the present invention is to add a fluorinated silicone to this polyolefin oligomer-based base oil.
The foaming property is improved by blending the oil.

In general, when an antifoaming agent such as silicone oil is blended with a base oil, the antifoaming property is improved, but the air release property is often deteriorated. Especially, it is recognized that this tendency is large in silicone oil. However, it has been found that the fluorinated silicone oil can improve the foaming-preventing property without deteriorating the air-releasing property. The fluorinated silicone oil used in the present invention is obtained by substituting a part of hydrogen of a hydrocarbon group of a siloxane such as polydialkylsiloxane with fluorine, and for example, a part of a methyl group of dimethylpolysiloxane is replaced with a peroxy group. A fluorinated product is exemplified.
It is also useful to introduce an ethyl group or a propyl group having a large number of carbon atoms instead of the methyl group. This fluorinated silicone oil has a viscosity at 25 ° C of 500-
A value in the range of 2,000 cP is suitable. The blending amount of this fluorinated silicone oil is a polyolefin oligomer.
It is in the range of 10 to 200 wtppm, preferably 20 to 100 wtppm, relative to the system synthetic oil.

When the fluorinated silicone oil is blended, the polyolefin oligomer-based synthetic oil may or may not have been subjected to the above-mentioned adsorption treatment. The best result is that not only anti-foaming properties but also air release properties are improved. The lubricating oil of the present invention is one in which a polyolefin oligomer-based synthetic oil is used as a lubricating base oil, and optionally a fluorinated silicone oil is blended, but if necessary,
An antioxidant, a copper deactivator, an antiwear agent, a dispersant, a viscosity index improver, a rust preventive, a colorant and the like are added to this.

[0010]

EXAMPLES Examples of the present invention are shown below. The blending ratio is part by weight. Moreover, the foam characteristics were measured as follows. -Air release property: According to ASTM-D-3427 The measurement temperature is 50 ° C unless otherwise specified, the unit is seconds, and the time until bubbles disappear. Foaming property: According to JIS-K-2518 The measurement temperature is 24 ° C unless otherwise specified, and the unit is ml.
After blowing a specified amount of air for 5 minutes, stop ventilation and immediately measure the amount of foam (foaming degree). Further, the amount of foam after standing for 10 minutes is measured (foam stability).

Examples 1 to 6 and Comparative Examples 1 to 16 16 parts of ethylene-α-olefin oligomer (L-Kant HC-40 manufactured by Mitsui Petrochemical Co., Ltd.) having a viscosity of 400 cSt at 40 ° C. and a viscosity of 30 cSt at 40 ° C. Α-
Olefin oligomer (PAO-6 manufactured by Chevron) 8
4 parts were blended to prepare a synthetic oil A having a viscosity of 46 cSt at 40 ° C. The ethylene-α-olefin oligomer was used as a synthetic oil B.

The synthetic oil A was subjected to adsorption treatment under the following conditions. The solid adsorbent powder is heated at 94 ° C. for 24 hours for activation, then mixed with synthetic oil A, and heated at 90 ° C.
(However, Example 6 was kept at 140 ° C.) and stirred for 1 hour, and then filtered without cooling to obtain an adsorption-treated synthetic oil AA. About this synthetic oil AA,
The foam characteristics were measured. For comparison, synthetic oil A
Also, the measurement was performed for synthetic oil B. The results are shown in Table 1.

[0013]

[Table 1]

Examples 7 to 12 and Comparative Examples 3 to 4 Synthetic oil B was subjected to an adsorption treatment in the same manner as in Example 6 to obtain an adsorption treated synthetic oil BB. This synthetic oil BB and α-
Olefin Oligomer (PAO-6 manufactured by Chevron)
Was mixed in a ratio of 84:16 to obtain a synthetic oil CC.
To this synthetic oil C, fluorinated silicone oil having a viscosity of 1000 cSt at 25 ° C. (trade name FS1265 manufactured by Toray Industries, Inc.)
Was blended and the foam characteristics were measured. For comparison, synthetic oil A was added to unmodified silicone oil having a viscosity of 12,500 cp at 25 ° C. (trade name: DC-20, manufactured by Dow Corning Co., Ltd.).
0) was blended and the same measurement was performed. The results are shown in Table 2.

[0015]

[Table 2]

[0016]

The lubricating oil of the present invention is excellent in foaming property represented by antifoaming property, foam eliminating property and / or air releasing property,
It is suitable as a lubricating oil for industrial machines that are often used in circulation, and not only contributes to downsizing of the circulating structure of the lubricating oil, but also extends the life of the machine that has a lubrication part and the life of the lubricating oil itself. Contribute.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area // (C10M 111/04 105: 04 107: 50) C10N 20:02 30:18 40:02 40 : 04 40:08 40:25 60:08 70:00 (72) Inventor, Katsuaki Furuya, 3-2-5, Kasumigaseki, Chiyoda-ku, Tokyo, Mitsuishi Petrochemical Industry Co., Ltd. (72) Inventor, Tatsuo Kinoshita, Chiba City 3, Chikusaigan, Hara City, Mitsui Petrochemical Industrial Co., Ltd.

Claims (5)

[Claims] 1. A lubricating oil comprising a polyolefin-oligomer-based synthetic oil as a lubricating base oil, wherein the polyolefin-oligomer-based synthetic oil is adsorbed by being brought into contact with an acidic solid adsorbent. oil. 2. The lubricating oil according to claim 1, wherein the acidic solid adsorbent is at least one adsorbent selected from activated clay, silica gel, alumina gel and zeolite. 3. A lubricating oil comprising a polyolefin oligomer-based synthetic oil as a lubricating base oil, and a fluorinated silicone oil blended therein. 4. The lubricating oil according to claim 3, wherein the polyolefin oligomer-based synthetic oil is adsorbed by being brought into contact with an acidic solid adsorbent. 5. A fluorinated silicone oil having a viscosity of 50 at 25 ° C.
The lubricating oil according to claim 3, which has a viscosity of 0 to 2,000 cP.