JPS6115920B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a power transmission fluid used in a power transmission mechanical device whose purpose is to transmit power hydraulically. More specifically, the present invention relates to a polycyclohexyl compound that is a power transmission fluid suitable for power transmission mechanical devices that require high viscosity characteristics. Traditionally, automotive transmissions, traction drives, hydraulics, shock absorbers, hydraulic steering, clutches, or other fluid-operated devices have been equipped with various techniques to reduce the friction and heat generated during their operation. Lubricants have been used. However, various mechanisms have been developed for power transmission devices such as automatic transmissions in automobiles.
As large amounts of power and high speeds are required to be transmitted, fluids with performance suitable for the operation of these mechanisms are required. To operate these complex mechanisms, fluids must perform several different actions. The role played by fluids is not only as a normal lubricant, such as removing heat generated by the friction of the operating members of power transmission machinery and lubrication to reduce friction, but also playing other important roles. need to be fulfilled. Power transmission mechanical devices that transmit power using fluids essentially rely on point contact and/or point contact between an input member and an output member.
Alternatively, it exerts its effect through rolling friction contact due to line contact. At the rolling contact surface, the fluid is trapped between the actuating members and forms a thin oil film, and at the same time very high pressure is applied to the oil film, causing the oil film to lose its fluidity and create rolling friction. Since power transmission by fluid is achieved by this rolling friction force, it is important that the fluid has a large rolling friction (expressed by a rolling friction coefficient) at the contact surface. Conventionally, power transmission fluids have been disclosed in U.S. Patent No. 3411369, U.S. Pat. -2229 and other technologies have been disclosed, and it is proposed to be used as a fluid for decalin, perhydroanthracene, polycyclohexyl, bicyclohexyl, dicyclohexyl, α-methylstyrene dimer hydride, adamantane, etc. has been done. However, the fluids proposed in the above materials have not been put into practical use due to reasons such as the rolling friction coefficient not being suitable for practical use and the difficulty in obtaining raw materials for implementation on an industrial scale. There aren't many. In JP-A No. 47-7664, a hydride of a linear dimer of α-methylstyrene was found to have a particularly large rolling friction coefficient.
Dicyclohexyl-2-methylpentane has been proposed. However, in addition to the high rolling friction coefficient, this fluid also has too low high-temperature viscosity, which is an important element that the fluid should have.
In order to improve this drawback, methods such as adding a thickener have been proposed. As can be seen in the development of automobile-related technology, in addition to the increase in power transmitted as horsepower increases, the operation of power transmission machinery has become faster.
Actuating members and transmission fluids are exposed to harsh conditions. Therefore, since the power transmission fluid is used under severe conditions, the viscosity of the fluid becomes an important factor. In order to maintain high-temperature viscosity under conditions where the temperature rises due to high-speed operation, the above-mentioned disclosed technology proposes the addition of a viscosity index improver, high molecular weight polybutylene, etc., but the added substances are It has a small rolling friction coefficient and is not suitable for the original purpose of a power transmission fluid. That is, although it meets the purpose of maintaining high-temperature viscosity, it is inevitable that the original purpose of utilizing rolling friction will be sacrificed. Regarding specific indicators of the viscosity required for fluids for transmissions of ordinary automobiles, the fluid standard of General Motors "Dexron" can be mentioned. Here 210〓(99
A high temperature viscosity of 7.0 cSt is required as the minimum viscosity at ℃). The inventors of the present invention have conducted various studies to solve the need for high-viscosity power transmission fluids, and as a result, they have discovered a high-viscosity power transmission fluid that itself has a large coefficient of rolling friction, and have completed the present invention. By using a high viscosity fluid according to the present invention, high temperature viscosity can be improved without sacrificing the properties of the power transmission fluid. That is, the present invention is based on the following general formula In the above general formula, n is an integer of 1 to 3, R ₁ , R ₂ , R ₃ and R ₄ are hydrogen atoms, methyl groups, ethyl groups, propyl groups. group or butyl group, and the total number of carbon atoms of R ₁ , R ₂ , R ₃ and R ₄ is 1 to 4
, R ₅ and R ₆ represent a hydrogen atom or a methyl group, and R ₇ and R ₈ represent a hydrogen atom or a methyl group or an ethyl group. When n in the formula is 4 or more, the viscosity of the compound is too high and the thermal stability is reduced, which is undesirable. When n is 0, the high temperature viscosity is low and the compound cannot be used alone, so it is not preferable. do not have. Furthermore, if the number of carbon atoms in R ₁ to _{R 8} in the formula increases, the viscosity becomes too high or the thermal stability decreases, so it is preferably within the above range. Any of the compounds represented by the above formula, alone or in a mixture of two or more, can be used as the power transmission fluid. The compound represented by the above formula can be produced by various methods, some examples of which are shown below. For example, when a polyphenyl compound is produced by coupling an aromatic compound with a dihalogenated alkane in which two halogen atoms are bonded to the same carbon, and then dehydrating and condensing it with an alkylbenzene using a carbonyl compound, substantially no aromatic components remain. It can be produced by hydrogenation as described above. Coupling can be achieved successfully, for example, by carrying out a conventional Friedel-Crafts reaction of benzene, toluene and ethylbenzene with 1,1-dichloroethane and 2,2-dichloropropane in the presence of a metal halide. for example,
By coupling benzene and 1,1-dichloroethane with an anhydrous aluminum chloride catalyst, poly(phenylethanes) containing 1,1-diphenylethane as a main component can be obtained. The dehydration condensation can be carried out using acetaldehyde on a mixture of the poly(phenylethanes) and alkylbenzene in the presence of a sulfuric acid catalyst.
In this case, in addition to heterogeneous dehydration condensation of poly(phenylethanes) and alkylbenzene, homogeneous dehydration condensation also occurs simultaneously, but these can be separated by precision distillation. The alkylbenzenes preferably used as raw materials are alkylbenzenes in which the total number of carbon atoms in side chain alkyl groups is 1 to 4. Although the transfer fluid of the present invention is not limited to, toluene, ethylbenzene, o-, m-, p-xylene, propylbenzene, kyumene, o-, m-, p-ethyltoluene, 1.2.3-, 1・2・4−, 1・
3,5-trimethylbenzene, butylbenzene,
O-, m-, p-diethylbenzene and the like are preferably used. As another example of the production method, the alkylbenzene described above is converted into styrene, α-methyl 2 styrenes per mole of alkylbenzene obtained by alkylation with styrenes such as styrene, vinyltoluene, and ethylstyrene.
A method of hydrogenating a polyphenyl compound added with ~4 moles can be mentioned. For the above hydrogenation, any commonly known aromatic ring hydrogenation catalyst can be preferably used.
For example, nickel, nickel oxide, nickel diatomaceous earth, Raney nickel, nickel copper, platinum, platinum oxide, platinum-activated carbon, platinum-rhodium, platinum-alumina, platinum-lithium-alumina, rhodium-
Activated carbon, palladium, cobalt, Raney cobalt, ruthenium, tungsten sulfide-nickel sulfide-alumina, etc. can be used favorably. The temperature of the hydrogenation reaction is preferably 20°C or higher and 250°C. If the temperature is lower than 20°C, the hydrogenation reaction will not be sufficiently carried out, and if the temperature exceeds 250°C, a decomposition reaction will occur and the yield will decrease. The pressure may be as long as it is necessary to maintain the liquid phase, ranging from normal pressure to 100
It can be carried out in a range up to atmospheric pressure. The reaction conditions are appropriately determined depending on conditions such as the reaction format, for example, batchwise or continuous, the amount and pressure of hydrogen that can be used, and the time required for the reaction. In hydrogenation, it is important to reduce the residual phenyl group to 2 mol% or less, and more preferably 0.5 mol% or less. Further, in the hydrogenation, an inert solvent such as a paraffinic solvent or a naphthenic solvent can also be used. Here, the power transmission fluid of the present invention (hereinafter referred to as "the fluid of the present invention") will be compared and explained with conventionally known power transmission fluids.

[Table] In order to explain that the fluid of the present invention has excellent characteristics as a power transmission fluid, the 6
Thermal stability and metal corrosion tests were conducted on various power transmission fluids. This test is carried out in an air temperature chamber.
The acidity, viscosity change, and weight change of the metal test piece were measured for the fluid after heat aging for 120 hours at a temperature of 150°C. The results shown in Tables 2 to 4 below were conducted under the following conditions. Sample amount: 300 ml Container: Glass cylindrical container with inner diameter of 70 mm Metal test pieces: Iron, copper, tin, zinc, silver. The dimensions of the test pieces are 20 mm x 30 mm x 1.5 mm, and the surface area is the same.

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【table】

[Table] From the results in Tables 2 to 4 above, it is clear that the fluid of the present invention is a fluid with excellent thermal stability.
In particular, the results in Table 4 show that Fluid-6, in which a viscosity improver was added for the purpose of improving viscosity, had an adverse effect on iron and copper. This means that by adding Fluid-3 as a viscosity improver, the stable Fluid-4 loses its heat resistance. In contrast, Fluid-1 and Fluid-2 of the present invention not only exhibit good stability by themselves, but also exhibit favorable effects when used as a viscosity improver, as in Fluid-5. Since power transmission fluids operate over a wide temperature range, viscosity is an important factor. In addition to initially satisfying certain viscosity conditions, it is important that the viscosity change during use be as small as possible. According to Table 3, the viscosity of Fluid-6 to which the viscosity improver was added was large, and the viscosity decreased. This is thought to be because the added polyisobutylene has worse thermal stability and is decomposed by long-term heating, indicating that the purpose of maintaining high-temperature viscosity cannot be achieved by simply adding a known viscosity improver. It is something. The above-mentioned "Dexron" fluid standard is one of the viscosity conditions that the power transmission fluid must first meet. According to this standard, 210〓
(99℃) is a value of 7.0cSt or higher. Table 5 below shows the viscosity measurement results for six types of power transmission fluids.

[Table] Fluid-1 and Fluid-2, which are the fluids of the present invention, not only have high-temperature viscosity that is preferable as a transmission fluid used at high temperatures, but also can be used as an additive to maintain high-temperature viscosity. It shows what is possible. Furthermore, the fluid of the present invention exhibits a high coefficient of rolling friction, which is the most important factor in power transmission, and even when added to known low-viscosity power transmission fluids that cannot maintain high-temperature viscosity, it exhibits an excellent coefficient of rolling friction. It shows. The rolling friction coefficient was measured according to the method described in Lubrication, 16 , 573 (1971).

[Table] As explained above, the fluid of the present invention is an excellent power transmission fluid in itself, but when used in actual power transmission machinery, depending on the type of device and the conditions under which it is used, It goes without saying that, as in the case of ordinary lubricating oils, various additives can be added to improve the properties of the lubricant to suit the conditions of use. The above additives include load-bearing additives, oil-based agents, anti-wear agents, extreme pressure additives, metal surface inert agents,
Rust inhibitors, corrosion inhibitors, cleaning dispersants, pour point depressants, antifoam agents, antioxidants, viscosity index improvers, lubricity agents, colorants, mold inhibitors, emulsifiers, demulsifiers, stain inhibitors etc., and these may be added as necessary. Below, a method for manufacturing the fluid used in the explanation up to now will be explained. Production Example 1 Production of the fluid of the present invention (Fluid-1) (a) Coupling of benzene Benzene 1 and 24 g of anhydrous aluminum chloride were stirred, and while maintaining the temperature at 10 to 15°C, 1.1-
250 g of dichloroethane was added dropwise over 3 hours. After the completion of the dropwise addition, the reaction mixture was further stirred and cooled for 8 hours to complete the reaction. After the reaction was completed, the reaction product was added to ice water to deactivate the catalyst, and neutralized and washed with water. After separating unreacted benzene at normal pressure, distillation is performed under reduced pressure of 3 mmHg to obtain a fraction 360 with a distillation temperature of 115 to 135°C.
g and 85 g of distillation residue were obtained. The distillate was determined to be 1.1- by NMR and mass spectrometry.
It was confirmed that it was diphenylethane. The distillation residue was further subjected to high vacuum distillation at 0.1 mmHg to recover 71 g of a fraction with a distillation temperature of 145°C to 220°C. This recovered heavy oil was analyzed by NMR, mass spectrometry, and liquid chromatography to reveal that di-α-phenylethylbenzene and 1,1-bis-(α-phenylethyl phenyl)ethane, that is, 3 and 4 molecules of It was confirmed that it was a mixture of benzene coupled with ethane. (b) Dehydration condensation reaction 210 g of xylene, 360 g of 1,1-diphenylethane obtained in section (a), and 500 ml of n-hexane as a solvent were stirred and cooled to a temperature of 5 to 10°C.
Next, 240 g of 90% sulfuric acid was added, and then 88 g of acetaldehyde was added dropwise over 4 hours while stirring and cooling. The reaction was completed 4 hours after the completion of the dropwise addition. After the reaction was completed, the sulfuric acid was separated and removed, the solution was washed with neutralized water, and the solvent and a small amount of unreacted xylene were separated at normal pressure. Next, distillation was performed under reduced pressure of 3 mmHg.
110g of the first distillate with a distillation temperature of 130~150℃, 275g of the second distillate with a distillation temperature of 185~230℃, and distillation residue
Obtained 193g. The structure of each component was confirmed by NMR, mass spectrometry, and liquid chromatography (shown in Table 7).

[Table] (c) Hydrogenation reaction 220g of the second distillate obtained in section (b) was
Put 18g into an autoclave with a capacity of 1,
Combines with hydrogen cylinder through pressure regulating valve,
The pressure inside the autoclave was maintained at 35 atmospheres. Start heating while continuing to stir,
The hydrogenation was completed by heating at 100°C for 3 hours, at 160°C for 4 hours, and finally at 180°C for 3 hours.
After cooling, the catalyst Raney nickel is filtered,
228 g of hydrogenated heavy oil was obtained. In order to remove the decomposed products generated in the hydrogenation process, this was distilled again under reduced pressure of 3 mmHg, and the distillate with a distillation temperature of 185 to 230 °C was collected.
Obtained 210g. This is the fluid of the present invention (fluid-1)
It is. Fluid-1 has a specific gravity of 0.887 (15/4℃, viscosity 624cSt [100〓 (38℃)], 27.4cSt [210〓
(99℃)] and is a colorless liquid with a flash point of 210℃. In addition, as a result of ultraviolet absorption analysis, the residual phenyl group was 0.47.
It was in mol%. Production Example 2 Production of the fluid of the present invention (Fluid-2) (a) Coupling product 115-135°C distillate fraction obtained in item (a) of Production Example 1
A mixture of 306 g and 54 g of recovered heavy oil was used. (b) Dehydration condensation reaction xylene 210g, n-hexane 500g as solvent
ml, 260 g of 90% sulfuric acid and 360 g of the mixture obtained in section (a)
The reaction was carried out in the same manner as in Production Example 1 using g.
Collect the solvent and unreacted xylene at normal pressure,
The following components were obtained by vacuum distillation at 0.1 mmHg (shown in Table 8).

[Table] (c) Hydrogenation reaction 220g of fraction-2 obtained in section (b) and 18g of Raney nickel were charged into an autoclave with a capacity of 1, and combined with a hydrogen cylinder through a pressure control valve, and the pressure inside the autoclave was adjusted. The pressure was maintained at 35 atmospheres. Start heating while continuing to stir, heat at 100°C for 3 hours, then at 160°C for 4 hours,
Finally, hydrogenation was completed by heating at 180°C for 3 hours. After cooling, the Raney nickel catalyst was filtered to obtain 225 g of hydrogenated heavy oil. To remove decomposition products generated during the hydrogenation process, this was re-dipped to 3 mm.
Distillation was carried out under reduced pressure of Hg to obtain 208 g of a fraction with a distillation temperature of 150 to 250°C. This is the fluid of the present invention (fluid-
2). The fluid of the present invention has a specific gravity of 0.898 (15/4
℃), viscosity 723cSt [100〓(38℃)], 30.3cSt
[210〓(99℃)], it is a colorless liquid with a flash point of 210℃. Further, as a result of ultraviolet absorption analysis, the residual phenyl group was 0.48 mol%. Production Example 3 Production of 2,4-dicyclohexyl-2-methylpentane (Fluid-4) (a) Linear dimerization of α-methylstyrene 500 g of α-methylstyrene with a purity of 99%, 25 g of mesityl oxide, and acid clay ( Mizusawa Chemical Co., Ltd.
5 g of Galeonite 036) was placed in a glass reactor equipped with a stirrer, and heated while stirring.
An exothermic reaction started at a temperature of around 65°C, and heating was stopped. When the temperature rose to 100°C, it was cooled and reacted at 100°C for 20 minutes, and when the heat generation decreased, it was heated again and the reaction was continued at a temperature of 95°C to 100°C for an additional 3 hours. After the reaction, the acid clay was filtered off and distilled under reduced pressure of 10 mmHg to obtain 50 g of light fraction (including mesityl oxide and unreacted α-methylstyrene) and 415 g of dimer (distillation temperature 170-180). °C) was obtained. According to gas chromatography analysis,
The purity of this linear dimer was 98%, and the remaining 2% was a cyclic dimer. (b) Hydrogenation reaction 400 g of a mixture of 98% α-methylstyrene linear dimer and 2% cyclic dimer obtained in item (a) above.
and 43 g of Raney nickel were placed in autoclave No. 1 and hydrogenated. The operation is as in Production Example 1.
The procedure was carried out in the same manner as in section (c). In order to remove the decomposed products produced in the hydrogenation step, distillation was carried out again under reduced pressure of 3 mmHg to obtain 409 g of a fraction with a distillation temperature of 145 to 160°C.
This was used as 2,4-dicyclohexyl-2-methylpentane (fluid-4) used in the comparative experiment. Fluid-4 has a specific gravity of 0.884 and a viscosity of 22.4 cSt [100
It was a colorless fluid with a temperature of 3.62 cSt (210 °C) and 3.62 cSt (99 °C). Further, as a result of ultraviolet absorption analysis, residual phenyl groups were found to be 0.27 mol%. That is, the fluid-4 used to explain the present invention is 2
% cyclic dimer hydride and 98% linear dimer hydride.

Claims (1)

[Claims] 1. In a power transmission fluid used in a power transmission device that transmits power via a fluid, the following general formula is used. (In the formula, n is an integer of 1 to 3, R ₁ , R ₂ , R ₃ and R ₄
is a hydrogen atom, a methyl group, an ethyl group, a propyl group, or a butyl group, and the total carbon number of R ₁ , R ₂ , R ₃ and R ₄ is 1 to 4, and R ₅ and R ₆ are hydrogen atoms or Methyl group, R ₇ and R ₈ are hydrogen atoms,
A power transmission fluid containing a compound represented by a methyl or ethyl group.