JP2003292978A - Fluid for traction drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive and readily producible fluid for traction drive having good low-temperature fluidity, a high viscosity index and excellent performances over the wide temperature range of low to high temperatures. <P>SOLUTION: The fluid for the traction drive comprises a di-(cycloalkyl)- alkylcyclohexane or a di(cycloalkyl)-cyclohexane represented by general formula (1) (wherein, R<SP>1</SP>denotes a hydrogen or a 1-4C alkyl group; and R<SP>2</SP>and R<SP>3</SP>denote each independently a 4-7C cycloalkyl group which may have a substituent). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD This invention relates to traction drive fluids. More specifically, the present invention relates to a fluid used in a traction drive device, that is, a device that transmits frictional force by rolling contact or the like to drive it.

[0002]

2. Description of the Related Art A traction drive fluid is a fluid used in traction drive devices such as continuously variable transmissions for automobiles, continuously variable transmissions for industry, and hydraulic equipment, and has a high traction coefficient and stability against heat and oxidation. And economic efficiency are required.

In recent years, reduction in size and weight of traction drive devices has been studied mainly for automobile applications. Along with that, even for traction drive fluids used in traction drive devices, performance that can withstand use under various severe conditions, especially from low temperature to high temperature (-30 to 140 ° C)
It is required that a high performance (high traction coefficient, proper viscosity, excellent heat and oxidation stability, etc.) can be stably exhibited over a wide temperature range up to a certain degree).

It is generally said that the size of the traction drive device is inversely proportional to the 0.45th power of the traction coefficient of the traction drive fluid used, and a traction drive fluid having a high minimum traction coefficient in the operating temperature range is used. As it is used, the traction drive device can be made smaller and lighter.

A fluid having a small viscosity index has a large increase in viscosity in a low temperature range, resulting in an increase in agitation resistance of the fluid, and a continuous transmission (Continuously Var).
iable Transmission, CV for short
The low temperature startability of T) deteriorates. On the other hand, in the high temperature range, the viscosity of the fluid rapidly decreases, so that the proper lubricating oil film cannot be maintained, which may cause fatigue damage. Therefore, it is desirable that the viscosity index of the fluid be as large as possible.

As a traction drive fluid, various compounds having an alicyclic structure have been proposed so far. However, the ester compound disclosed in JP-B-61-44918 has a remarkably low traction coefficient at high temperature and lacks thermal stability, so that it cannot be put to practical use. In addition, JP-A-1-198
Although the dimer hydride of camphene disclosed in Japanese Patent No. 693 has a high traction coefficient at high temperature, it has a problem of low temperature fluidity because it has a high pour point of −27.5 ° C. Further, the dimerized norbornanes disclosed in Japanese Examined Patent Publication No. 7-103387 have a high traction coefficient at high temperatures, but their low-temperature fluidity is not sufficient. Further, since the synthetic route is long, it cannot be said that it can be industrially advantageously produced.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a traction drive fluid having good low temperature fluidity, high viscosity index and excellent performance over a wide temperature range from low temperature to high temperature. .

[0008]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above object, and found that an alkylcyclohexane derivative or a cyclohexane derivative having two cycloalkyl groups on a cyclohexane ring was
The inventors have found that they can be easily industrially produced and have excellent traction performance, and have completed the present invention.

Thus, according to the present invention, the general formula (1)

[Chemical 2] (In the formula, R ¹ represents hydrogen or an alkyl group having 1 to 4 carbon atoms. R ² and R ³ each independently represent a cycloalkyl group having 4 to 7 carbon atoms which may have a substituent. A fluid for traction drive containing di (cycloalkyl) -alkylcyclohexane or di (cycloalkyl) -cyclohexane represented by the formula (hereinafter, referred to as "di (cycloalkyl) -alkylcyclohexane or di (cycloalkyl)" is provided. ) -Cyclohexane "
Is referred to as di (cycloalkyl)-(alkyl) cyclohexane). Both R ² and R ^{3 in} the above formula (1) are preferably cyclopentyl.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A traction drive fluid according to the present invention contains di (cycloalkyl)-(alkyl) cyclohexane represented by the general formula (1). Here, R ¹ in the formula (1) represents hydrogen or an alkyl group having 1 to 4 carbon atoms. Also, R ² and R
^3's each independently represent a cycloalkyl group having 4 to 7 carbon atoms which may have a substituent.

In the formula (1), R ² and R ³ are R
^It may be bonded to any position on the cyclohexane ring with respect to ¹ . That is, the fluid of the present invention may be a mixture of isomers having different bonding positions of R ¹ , R ² and R ³ on the cyclohexane ring. The preferred substitution position of R ² and R ³ with respect to R ¹ is a structure in which both are meta-substituted, or a structure in which any one of R ² and R ³ is ortho-substituted and the remaining one is para-substituted, but a meta-disubstituted product Those containing as a main component are particularly preferably used.

R ¹ is, for example, methyl, ethyl,
Substituents such as n-propyl, isopropyl, n-butyl, isobutyl, t-butyl and the like can be mentioned. Of these substituents, methyl and ethyl are preferred.

R ² and R ³ are not particularly limited as long as they are cycloalkyl groups having 4 to 7 carbon atoms that constitute a ring, but cycloalkyl groups having 4 to 6 carbon atoms are preferable, and those having 5 carbon atoms. Is more preferable. The cycloalkyl group may be monocyclic or bridged (polycyclic), but monocyclic is preferable. Further, it may be unsubstituted or may have a substituent. The substituent on the cycloalkyl group has, for example, 1 carbon atom.
~ 5 lower alkyl groups and the like. R ² and R
^{Although 3} may be any combination of such cycloalkyl groups, those having the same structure are preferably used.

Specific examples of R ² and R ³ include cyclobutyl, 2-methylcyclobutyl, 2-ethylcyclobutyl, cyclopentyl, 2-methylcyclopentyl, 3
-Methylcyclopentyl, 3-ethylcyclopentyl,
3-n-propylcyclopentyl, 3-n-butylcyclopentyl, 3-n-pentylcyclopentyl, cyclohexyl, 2-methylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, cycloheptyl, cyclooctyl, norbornan-2-yl, etc. Is mentioned. Of these, cyclopentyl is preferred.

The di (cycloalkyl)-(alkyl) cyclohexane of the present invention, wherein R ² and R ³ are monocyclic, include, for example, di (cyclobutyl) -methylcyclohexane and di (cyclobutyl) -ethyl. Cyclohexane, di (cyclobutyl) -butylcyclohexane,
Di (cyclobutyl) -isobutylcyclohexane, di (cyclopentyl) -methylcyclohexane, di (cyclopentyl) -ethylcyclohexane, di (cyclopentyl) -propylcyclohexane, di (cyclopentyl) -isopropylcyclohexane, di (cyclopentyl) -butylcyclohexane, di (cyclopentyl) -butylcyclohexane Cyclopentyl)-
Pentylcyclohexane, di (cyclohexyl) -methylcyclohexane, di (cyclohexyl) -ethylcyclohexane, di (cycloheptyl) -methylcyclohexane, di (cycloheptyl) -ethylcyclohexane,
Di (cyclooctyl) -methylcyclohexane, di (cyclooctyl) -ethylcyclohexane; di (cyclobutyl) -cyclohexane, di (cyclopentyl) -cyclohexane, di (cyclohexyl) -cyclohexane,
Examples thereof include di (cycloheptyl) -cyclohexane and di (cyclooctyl) -cyclohexane. Among these, di (cyclopentyl) -methylcyclohexane, di (cyclopentyl) -ethylcyclohexane and di (cyclopentyl) -cyclohexane are preferable, and 3,
More preferred is 5-di (cyclopentyl) -methylcyclohexane.

Further, as R ² and R ³ having a bridged ring structure, for example, di (norbornyl) -methylcyclohexane, di (norbornyl) -ethylcyclohexane,
Di (norbornyl) -propylcyclohexane, di (norbornyl) -isopropylcyclohexane, di (norbornyl) -butylcyclohexane, di (norbornyl) -isobutylcyclohexane; di (norbornyl)
-Including cyclohexane, those having a lower alkyl group having 1 to 5 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and n-pentyl substituted on the norbornane ring of these compounds. To be

The method for producing such di (cycloalkyl)-(alkyl) cyclohexane is not particularly limited, and those obtained by a known method may be used. For example, it can be easily produced by subjecting di (cycloalkyl)-(alkyl) benzene as a raw material to a hydrogenation reaction in the presence of a hydrogenation catalyst such as a Raney nickel catalyst or a palladium-supported catalyst.

The di (cycloalkyl)-(alkyl) benzene is obtained by using (alkyl) benzene and a monocyclic or bridged cyclic cycloalkene or cycloalkyl halide as a raw material, such as aluminum chloride and aluminum bromide. It can be produced by reacting in the presence of a simple Friedel-Crafts type catalyst. Cycloalkene or cycloalkyl halide is (alkyl)
It is used in an amount about twice the molar amount of benzene.

The production of di (cycloalkyl)-(alkyl) benzene can be carried out in the presence or absence of a reaction solvent. When using a reaction solvent,
It is preferable to use an inert solvent that does not affect the catalytic activity. Examples of such an inert solvent include chain-like (straight or branched chain) such as n-pentane, n-hexane and isohexane, or cyclic aliphatic hydrocarbon such as cyclopentane, cyclohexane and methylcyclohexane.

The conditions for the hydrogenation reaction of di (cycloalkyl)-(alkyl) benzene may be the usual conditions used for hydrogenating benzenes. Hydrogen pressure is 0.1-50
MPa, preferably 0.1 to 30 MPa, particularly preferably 0.5 to 10 MPa is adopted. The solvent may or may not be used, but when it is used, it is preferable to use a nonpolar solvent that does not affect the catalytic activity of the hydrogenation catalyst. As the hydrogenation catalyst, it is preferable to use an iron group metal such as iron and nickel of Group VIII of the periodic table and a platinum group metal such as palladium and rhodium as a supported catalyst. The catalytic amount is di (cycloalkyl)-
0.01-5 for 100 parts by weight of (alkyl) benzene
It is appropriately selected from the range of 0 parts by weight, preferably 0.05 to 10 parts by weight. The hydrogenation reaction temperature is 0 to 200 ° C.
It is done in the range of.

The traction drive fluid of the present invention is
Although it may contain only di (cycloalkyl)-(alkyl) cyclohexane as described above, it may be used as a mixture with a known fluid, if necessary.
At this time, other fluids to be mixed include not only those which have been conventionally used as a fluid for a traction drive but also various fluids such as oil which has a low traction performance and is not in practical use.

Examples of such other fluids include mineral oils such as paraffinic mineral oil, naphthenic mineral oil and intermediate mineral oil,
A very wide range of liquid substances such as norbornane derivatives, polybutene, poly α-olefins, synthetic naphthenes, esters and ethers can be mentioned. Among them, norbornane derivatives, polybutene, and synthetic naphthenes are preferable. It should be noted that di (cycloalkyl)-(alkyl) benzene, which is an unhydrogenated product of the fluid of the present invention, is also a fluid that can be preferably used by mixing with the fluid for traction drive of the present invention.

The norbornane derivative is, for example,
2,2-dimethyl-3-cyclohexanoyloxymethyl-bicyclo [2.2.1] heptane, 2,2-dimethyl-3-cyclohexanoyloxycarbonyl-bicyclo [2.2.1] heptane, 2, 3-dimethyl-2-
[(3-Methylbicyclo [2.2.1] hept-2-yl) methyl] bicyclo [2.2.1] heptane, di (bicyclo [2.2.1] hept-2-yl) ether, etc. Can be mentioned.

As the synthetic naphthene, an alkane derivative having two or more cyclohexane rings, an alkane derivative having one or more decalin rings and one or more cyclohexane rings, an alkane derivative having two or more decalin rings, a cyclohexane ring or a decalin ring. Examples thereof include compounds having a structure in which two or more are directly bonded. Specific examples thereof include 1-cyclohexyl-1-decalylethane, 1,3-dicyclohexyl-3-methylbutane, 2,4-dicyclohexylpentane, 1,2-bis (methylcyclohexyl) -2-methylpropane,
Examples thereof include 1,1-bis (methylcyclohexyl) -2-methylpropane and 2,4-dicyclohexyl-2-methylpentane.

When the above-mentioned other fluids are mixed with di (cycloalkyl)-(alkyl) cyclohexane, the compounding ratio thereof is not particularly limited, and the desired performance (for example, traction performance) and the other fluids to be mixed. It may be changed as appropriate depending on the type of. Di (cycloalkyl)-
The amount of the (alkyl) cyclohexane blended is usually 5% by weight or more, preferably 30% by weight or more, based on the whole mixed fluid.

The traction drive fluid of the present invention further contains, if necessary, an antioxidant, a rust preventive, a detergent dispersant, a pour point depressant, a viscosity index improver, an extreme pressure agent, an antiwear additive, and a metal. Various additives such as an anti-fatigue agent, a defoaming agent, an oiliness improver, and a coloring agent can be added in appropriate amounts. The blending ratio of various additives is not particularly limited, and is usually 0 to 95% by weight, preferably 1 to 95% by weight of the whole traction drive fluid.
It may be 70% by weight.

The traction drive fluid according to the present invention usually has a traction coefficient of 0.07 or more at -30 to 140 ° C. The viscosity index is usually 10 or more, preferably 20 or more.

The traction drive fluid of the present invention is
It has good low-temperature fluidity, high viscosity index, excellent performance over a wide temperature range from low temperature to high temperature, and can be manufactured at low cost, making it suitable for traction drive devices used in various machines, equipment, devices, etc. used.
In addition, lubricants for HDDs, lubricants for refrigerants, oils for rock drills, oils for vacuum pumps, oils for diffusion vacuum pumps, grease base oils and mixed oils, solvents for patterning the surface of polymer materials such as resins, metals, It can also be used as a solvent for coating the surface of an inorganic material such as a polymer or ceramic with a polymer such as a resin.

[0029]

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Parts and% in the following are by weight unless otherwise specified.

(Production Example 1) To a glass reaction vessel equipped with a stirrer, a reflux condenser and a thermometer, 100 parts of toluene, 150 parts of cyclopentene, and 5 parts of powdered anhydrous aluminum chloride were charged. The contents were heated to 80 ° C. and reacted for 4 hours while stirring well. After completion of the reaction, 50 parts of 25% aqueous sodium hydroxide solution was added, and the mixture was stirred at 50 ° C. for 30 minutes and then cooled to room temperature. The oil layer obtained by removing the water layer separated into two layers is subjected to vacuum distillation to obtain a boiling point range of 325 to 33.
The 0 ° C. fraction was separated. As a result of analyzing this fraction by gas chromatography and ¹ H-NMR, 3,5
It was found to be a mixture of 80% dicyclopentyltoluene and 20% 2,4-dicyclopentyltoluene. The yield was 85% based on cyclopentene.

To a 1 L autoclave was added 500 parts of the above-obtained dicyclopentyltoluene (a mixture of 80% 3,5-dicyclopentyltoluene and 20% 2,4-dicyclopentyltoluene) and 3 parts of Raney nickel catalyst. Heated to 180 ° C. with stirring. Hydrogen was introduced therein, and the mixture was stirred at 180 ° C. under a pressure of 2 MPa for 4 hours to carry out a hydrogenation reaction. Then, after cooling to room temperature and separating the catalyst by filtration, the filtrate was distilled under reduced pressure to separate a fraction having a boiling point range of 154-156 ° C./0.5 kPa. As a result of analyzing this fraction by gas chromatography and ¹ H-NMR, it was found to be a mixture of 80% of 3,5-dicyclopentylmethylcyclohexane and 20% of 2,4-dicyclopentylmethylcyclohexane. The yield was 95% based on dicyclopentyltoluene. Table 1 shows the physical properties of the obtained fraction.

(Production Example 2) A synthesis reaction of di (cycloalkyl) -alkylbenzene was carried out in the same manner as in Production Example 1 except that 207 parts of norbornene was used instead of 150 parts of cyclopentene. By distilling the obtained oil layer under reduced pressure, a fraction having a boiling point range of 171 to 175 ° C./0.5 kPa was separated. This fraction was subjected to gas chromatography and ¹ H-N
As a result of analysis by MR, 3,5-dinorbornyltoluene 85% and 2,4-dinorbornyltoluene 15%
It was found to be a mixture of The yield was 87% based on norbornene.

As a result of hydrogenating this product in the same manner as in Production Example 1, 3,5-dinorbornylmethylcyclohexane 8 was obtained.
It was found to be a mixture of 5% and 2,4-dinorbornylmethylcyclohexane 15%. The yield was 95% based on dinorbornyltoluene. Table 1 shows the physical properties of the obtained fraction.

(Example 1) The traction coefficient of di (cyclopentyl) -methylcyclohexane obtained in Production Example 1 was measured by a two-cylinder friction tester. That is,
Cylinders of the same size in contact (diameter 52 mm, thickness 6 m
m is a Tyco type with a radius of curvature of 10 mm on the driven side and a flat type without crowning on the driving side) at a constant speed,
The rotation speed of the other was continuously changed, a load of 98.0 N was applied by a weight to the contact portion of both cylinders, the tangential force generated between both cylinders, that is, the traction force was measured, and the traction coefficient was obtained. The cylinder was made of bearing steel SUJ-2 mirror finish and had an average peripheral speed of 6.8 m / sec and a maximum Hertz contact pressure of 1.23 GPa. When measuring the traction coefficient at a fluid temperature (oil temperature) of 140 ° C, the oil tank is heated by a heater to raise the oil temperature from 40 ° C to 140 ° C, and the traction coefficient at a slip ratio of 5%. I asked. The results are shown in Table 1.

Example 2 The traction coefficient was measured in the same manner as in Example 1 except that the di (norbornyl) -methylcyclohexane obtained in Production Example 2 was used. The results are shown in Table 1.

(Comparative Example 1) 2,3-dimethyl-2-2, which is known to obtain a high traction coefficient
The traction coefficient of [(3-methylbicyclo [2.2.1] hept-2-yl) methyl] bicyclo [2.2.1] heptane was measured in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 The traction coefficient of cyclohexyltetrahydrocyclopentadiene, which is known to have a high traction coefficient, was measured in the same manner as in Example 1. The results are shown in Table 1.

[0038]

[Table 1]

From Table 1, the di (cycloalkyl) -alkylcyclohexanes of Examples 1 and 2 were compared with the bicyclo [2,2,1] heptane derivative of Comparative Example 1 and the cyclohexyltetrahydrocyclopentadiene of Comparative Example 2. It also shows a higher viscosity index and a higher traction coefficient from a low temperature to a high temperature, and it is clear that the fluidity at a low temperature is also excellent.

[0040]

Since the fluid of the present invention has a high traction coefficient from low temperature to high temperature, it is possible to improve the transmission efficiency of various traction drive devices. As a result, it is possible to reduce the size and weight of the traction drive device, increase the output, and the like, and it can be widely used for various mechanical products such as an automotive or industrial continuously variable transmission, and further a hydraulic device. Further, the present fluid has an advantage that it can be produced at a low cost by a simple reaction process.

Claims (2)

[Claims] 1. A compound represented by the general formula (1): (In the formula, R ¹ represents hydrogen or an alkyl group having 1 to 4 carbon atoms. R ² and R ³ are each independently a cycloalkyl group having 4 to 7 carbon atoms which may have a substituent. A fluid for traction drive containing di (cycloalkyl) -alkylcyclohexane or di (cycloalkyl) -cyclohexane represented by 2. The traction drive fluid according to claim 1, wherein R ² and R ³ are cyclopentyl.