JPS6256920B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a lubricating oil for a power transmission device, and particularly to a lubricating oil for a power transmission device suitable for use in a traction drive. Gears and hydraulic devices have traditionally been used to transmit power and change speeds, but a drive system called traction drive (rolling friction drive) that uses point or line contact between rotating rigid bodies is also known. etc., and there is little vibration during operation.
Also, due to its high power transmission efficiency, it is beginning to be put into practical use in some industrial machinery. In this case, the most suitable lubricating oil must be selected from the functional point of view as the oil present in the contact area.
In other words, the oil present in the contact area undergoes a reversible glass transition under high pressure and increases in viscosity, which increases the power transmission effect at the rotating contact surface.
It has the property of returning to a fluid state immediately after leaving the contact surface, prevents direct contact between metals, prevents seizure, wear, and fatigue damage, and also has important properties such as rust prevention and cooling similar to general lubricating oil. It must also have an effect. The present invention provides a lubricating oil for such a power transmission device,
In particular, it relates to lubricating oils suitable for use in traction drives. Friction or traction drive devices for power transmission have been described in many prior technical documents, such as U.S. Pat. No. 3,394,603;
No. 3411369, Journal of Chemical and Engineering Data Vol. 5 No. 4 499~
507 pages, detailed in the proceedings of a symposium on rolling contact phenomena by Huiko et al., pages 157-185, Nilsevier Publishing House (Amsterdam), 1962. Lubricating oils for traction drives include mineral oil (Japanese Patent Publication No. 39-24635), polymethyl methacrylate (Japanese Patent Publication No. 48-31828), pivalic acid monoester (Japanese Patent Publication No. 49-11309), and halogenated alkylnaphthalene (Japanese Patent Publication No. 49-11309). Publication No. 49-16900), adamantane (Japanese Patent Publication No. 48-42067, 48-42068), polyolefins (Japanese Patent Publication No. 4766-1976, 47-2229)
), alkylnaphthalene (U.S. Patent No.
2549377), but there are also many proposals regarding naphthenic oils having hydrogenated rings. The proposed naphthenic oils include dicyclohexylethane (Japanese Patent Publication No. 53-36105), hydrogenated condensed ring compounds (US Pat. No. 3,411,369), and naphthenes having one or more saturated carbon rings (US Pat. No. 3,411,369).
3440894), naphthenes having two or more saturated carbon rings (Japanese Patent Publication No. 47-35763, U.S. Patent No. 3925217)
(U.S. Pat. No. 3,595,796 and U.S. Pat. No. 3,595,797). Also known are compounds obtained by hydrogenating alkylation reaction products of xylene and/or toluene and styrene (mainly hydrogenated 1,1-diallylethane compounds). Furthermore, the technology described in JP-A-55-78089 and JP-A-55-78095 uses pyrolysis oil of petroleum hydrocarbons and unreacted distillate during the production of petroleum resin as a method for producing power transmission fluid. The raw material is minutes. The techniques described in the aforementioned US Pat. No. 3,440,894 and US Pat. No. 3,925,217 include a wide range of naphthenic compounds and exemplify numerous naphthenes. Judging from these prior art documents, naphthenic oils having hydrogenated rings generally have excellent properties as lubricating oils, especially lubricating oils for traction drives. However, when we examine the contents of these numerous publications and documents, we find that even though naphthenic oils are generally effective, their performance as lubricating oils for traction drives varies depending on the type, and their performance is unpredictable. It can be seen that compounds exhibiting this were discovered one after another. Therefore, the object of the present invention is to provide not only excellent traction properties but also excellent performance in terms of oxidation stability, corrosion resistance, etc., and, from an industrial standpoint, using extremely inexpensive raw materials. An object of the present invention is to provide a lubricating oil for power transmission devices that can be easily synthesized. The present invention uses dicyclopentadiene in an amount of 20% by volume or more (cyclopentadiene may be included in any proportion, and the same applies to the present specification. This is true because dicyclopentadiene and cyclopentadiene are in an equilibrium relationship. Boiling point range (converted to normal pressure) obtained by hydrogenating unsaturated bonds (including benzene nuclei) of the polymerization reaction product of unsaturated hydrocarbons (which are naturally well known to those in the industry)
A lubricating oil for power transmission devices whose main component is a fraction with a temperature of 250 to 450°C. Here, the boiling point range (converted to normal pressure) is
For distillates below 250°C, the flash point of the product lubricating oil is 450°C.
A fraction exceeding 0.degree. C. is unfavorable in terms of viscous resistance and cooling performance. Therefore, in the present invention, those outside the boiling point range of the present invention are excluded. The raw materials used in the present invention are mainly distillates containing unsaturated hydrocarbons produced together with basic petrochemical raw materials such as ethylene and propylene by thermal decomposition of naphtha, etc., that is, generally, isoprene, pentadiene, pentene, methyl butene, Cyclopentene, cyclopentadiene, styrene,
Mixtures or single compounds of allylbenzene, α-methylstyrene, vinyltoluene, β-methylstyrene, divinylbenzene, methylcyclopentadiene, etc. are preferred. The raw material used in the present invention is a mixture of this and dicyclopentadiene, and dicyclopentadiene can be obtained by concentrating decomposition products obtained by thermal decomposition of petroleum hydrocarbons or by other methods. However, if the fraction obtained by thermal decomposition already contains dicyclopentadiene in an amount of 20% by volume or more, preferably 30 to 60% by volume, it is not necessary to add dicyclopentadiene. The content of dicyclopentadiene in the mixed raw materials is adjusted to 20% by volume or more, more preferably 30 to 60% by volume in the raw material oil. If it is less than this, the traction coefficient of the reaction product will be low. Moreover, if it exceeds 60% by volume, the yield of the liquid reactant may decrease. The reaction method of the present invention includes, for example, a method using a Friedel-Crafts catalyst such as boron trifluoride or aluminum chloride, and a method in which a non-catalytic thermal reaction is performed at a high temperature of 250° C. or higher. When using a method using an aluminum chloride catalyst, the temperature is 0°C to 150°C and the pressure is normal pressure to
A range of 50 atm is desirable. Next, in the present invention, the reaction product obtained as described above is hydrogenated using a hydrogenation catalyst such as a nickel catalyst. As this hydrogenation catalyst, platinum,
Palladium, rhodium, ruthenium or nickel catalysts are preferred; the amount of nickel catalyst used is 0.1
A range of 20% by weight is preferred. Also, the hydrogen pressure is
10 to 200 Kg/cm ² G is suitable, and the hydrogenation reaction temperature is 100 to 200°C, preferably 140 to 170°C. Once the desired hydrogenation rate is obtained, the reaction is stopped and the hydrogenated product is separated. The hydrogenation rate is at least 80%, preferably 90% or more, and more preferably 95% or more. This separation may be carried out by simply removing the catalyst, and if necessary, ordinary lubricating oil treatment methods such as filtration and activated clay treatment can also be employed. Since the lubricating oil according to the present invention is mainly composed of a compound having dicyclopentadiene as its core, it differs from the compounds described in the above-mentioned JP-A-55-78089 and JP-A-55-78095. Cyclopentadiene bone compound shows excellent performance as a lubricant for power transmission devices. The lubricating oil according to the present invention may contain a small amount of mineral oil, other naphthenic oil, etc., and may also contain one or two additives such as antioxidants, which will be described later.
It goes without saying that more than one species can be contained. Furthermore, there is no problem in the presence of a small amount of by-products generated during the process of manufacturing the lubricating oil of the present invention. The traction coefficient is generally measured using a traction drive device, but in the present invention, a Soda type cylindrical friction tester was used. Traction (rolling friction) occurs at three contact points between the central cylinder and three cylinders placed outside, and the same vertical load acts on the contact points. The surface pressure at this time is 0.575 to 1.157 GPa in terms of average Hertzian pressure. Other conditions are as shown in Table 1 below.

【table】

[Table] The operating procedure for the experiment is to first adjust the rotation speed to
After applying a load while keeping the outer cylinder constant, the slip rate was increased by increasing only the rotational speed of the outer cylinder, and changes in friction torque or traction coefficient relative to the slip rate were continuously determined. Friction torque was measured by directly measuring the torsional moment of the central non-centered support shaft using a resistance wire strain gauge. The traction coefficient measured under these conditions shows a tendency to first rise linearly as the slip rate increases, and then to reach a maximum and then decline. In this case, the particularly important region from a practical standpoint is the initial linear region where the heat generated by shearing the oil film is not large, and the traction coefficient in this region will be of particular interest below. As an example, the traction coefficient measured at an average Hertz pressure of 1.157 GPa, a rotational speed of 4.19 m/s, and a sliding speed of 0.022 m/s is shown in Table 2 below.
0.080 to 0.092, which is clearly superior to these hydrocarbons. Note that the lubricating oil according to the present invention is economically advantageous because extremely inexpensive raw materials are used in its manufacturing method.

[Table] In addition to the above-mentioned traction properties, the properties required for lubricating oils for traction drives include oxidation stability, viscosity index, corrosion resistance, abrasion resistance, rust prevention properties, and other properties required for general lubricating oils. Examples include rubber swelling properties and anti-foaming properties, and it is necessary to mix appropriate additives depending on each use. Although the lubricating oil according to the present invention sufficiently has the above-mentioned various performances, in order to improve these performances, these additives, such as 2.6-dita as an antioxidant, are added to the lubricating oil according to the present invention. -Alkyl phenols such as shari-butyl para-cresol, sulfur and phosphorus compounds such as zinc dialkyldithiophosphate,
It is possible to add one or more of amines, esters, and metal salts as rust preventive agents, polymethacrylates as viscosity index improvers, and silicone polymers as antifoaming agents. The present invention will be illustrated below with reference to Examples, but the embodiments of the present invention are not limited thereto. Note that in the following description, "unit" refers to "capacity unit" unless otherwise specified. Example Boiling point range 145°C to 199°C fraction of pyrolysis gasoline by-produced by naphtha decomposition (main components are vinyltoluene 19%, indene 16%, dicyclopentadiene 15%)
%, methylindene 5%, methylstyrene 4%)
and 50 parts of dicyclopentadiene were mixed, and the mixture was reacted with an aluminum chloride catalyst at a temperature of 80°C and a pressure of normal pressure. This reaction product was distilled to obtain a fraction with a boiling point range (converted to normal pressure) of 250 to 450°C (yield
32% by weight). This fraction was hydrogenated using a nickel catalyst at a pressure of 45 kg/cm ² , a temperature of 200°C, and a reaction time of 5 hours, but as a result of infrared absorption analysis and ultraviolet absorption analysis, no residual unsaturation was detected. . The hydrogenation yield of the above fraction is approximately 100% by weight.
It was hot. The catalyst was separated from the hydrogenated product by a filtration separation method. Regarding the lubricating oil of the present invention obtained as described above,
phenolic and zinc antioxidants, respectively.
Added 0.5% by weight and conducted oxidation test JIS-K-2514-
The test was carried out in accordance with the basic procedure described in Section 3.2 (Test method for lubricating oil oxidation stability for internal combustion engines), 1980 (Lubricating oil oxidation stability test method). The results are shown in the 4th section below.
Tables 5 and 6 show the results. Tables 4 to 6 below show the following commercially available naphthenic mineral oils and commercially available α-methylstyrene linear dimeric hydrogen compound-based traction drive lubricating oils (Tokuko Showa).
47-35763) and the oxidation test results of the lubricating oil according to the present invention. [Commercial naphthenic mineral oil] Specific gravity [15/4°C] 0.9047 Appearance Pale yellow transparent viscosity [cSt40°C 9.789 100°C] 2.350 Flash point [°C] 146 Pour point [°C] <-50 The test conditions are as specified in Section 3 below. As shown in the table.

【table】

【table】

【table】

[Table] As is clear from the results shown in Tables 4 to 6 above, it can be seen that the lubricating oil according to the present invention has extremely excellent stability. Furthermore, the traction coefficient of the lubricating oil of the present invention was 0.091 as a result of measurement under the conditions described in the detailed description of the invention, and was found to be extremely excellent. Comparative Example In the above example, the boiling point range 145°C to 199°C fraction (dicyclopentadiene content 15% by volume) of pyrolysis gasoline by-produced by naphtha decomposition was used as the raw material, except that dicyclopentadiene was not added. A comparative lubricating oil was obtained by carrying out the same operation as in the above example. Results of measuring the traction coefficient of the lubricating oil for this comparison using the same measurement method as in the above example.
0.065, which was found to be inferior to the lubricating oil of the present invention.

Claims (1)

[Scope of Claims] 1 Contains 20% by volume or more of dicyclopentadiene obtained by thermally decomposing petroleum hydrocarbons, or 20% by volume
The boiling point range (normal pressure equivalent) obtained by hydrogenating the unsaturated bonds (including benzene nuclei) of the polymerization reaction product of the unsaturated hydrocarbon prepared above is 250
Lubricating oil for power transmission equipment consisting of saturated hydrocarbons at ~450℃. 2. The lubricating oil for a power transmission device according to claim 1, wherein the power transmission device is a traction drive.