JPH06271588A - Cyclohexylmethylsilicone, its production and fluid for traction drive containing the compound - Google Patents

Abstract

PURPOSE:To provide a new compound useful as a traction drive fluid having high traction coefficient, exhibiting constantly stable high power transmission performance and enabling the reduction of the size and weight and the prolongation of the life of a traction drive apparatus. CONSTITUTION:The compound of formula I (R<1> to R<8> are methyl or cyclohexyl; the content of cyclohexyl is 20-100% of the total substituent and at least one of R<1> to R<6> is cyclohexyl; n is 0-3), e.g. 1,1,3-tricyclohexyl-1,3,3- trimethyldisiloxane. The compound can be produced e.g. by hydrogenating a methylphenylsilicone of formula II (R<9> to R<16> are methyl or phenyl; the content of phenyl is 20-75% of the total substituent and at least one of R<9> to R<14> is phenyl; n is 0-2) in the presence of a hydrogenation catalyst containing nickel, etc., in a solvent such as n-heptane. The hydrogenation reaction is preferably carried out at 60-200 deg.C under a hydrogen pressure of 20-100kgf.cm<2>.G.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel chemical substance, cyclohexylmethyl silicone, a process for producing the same, and a traction drive fluid using the same. More specifically, the present invention is a novel traction drive fluid having a high traction coefficient suitable for a traction drive having a large torque capacity and severe operating conditions such as an automobile transmission, and a novel component thereof. The present invention relates to a chemical substance, cyclohexylmethyl silicone, and a method for producing the same.

[0002]

2. Description of the Related Art A traction drive device has a rolling resistance due to a resistance force against shearing caused by a fluid oil film sandwiched between a cylindrical or conical rotating body, which loses fluidity under high pressure and hardens. -A power transmission device that utilizes sliding friction. This traction drive device has been especially researched in recent years for higher performance or smaller size and light weight, mainly for automobile applications, and has excellent performance that can withstand fluids for traction drive as automobiles, especially transmission torque capacity (traction coefficient). Those with high prices are required.

Therefore, by utilizing a hydrocarbon of a special synthesis system, a traction drive fluid showing a high traction coefficient is disclosed in JP-A-1-149895 and JP-A-2-
88697, JP-A-63-222127, JP-B-5
Many proposals such as No. 3-36105 have been made. However, most of these cannot be said to have a sufficiently high traction coefficient when considered for applications such as automobiles, and high load and high shear due to reduction in size and weight for using traction drive devices in automobiles. In order to cope with the demand for force, it is required to develop and use a fluid having a high traction coefficient as well as practical performances such as viscosity temperature characteristics and low temperature fluidity.

A few fluids for traction drives using silicone compounds are disclosed in Japanese Patent Publication No. 2-11639.
And JP-A-60-135490. For example, Japanese Patent Publication No. 2-11639 examines a traction liquid containing trimethylsiloxy endblocked methylphenyl silicone and trimethylsiloxy endblocked cyclohexylmethyl silicone. However, although these have excellent fluidity and miscibility, especially in the low temperature range, they cannot be said to have sufficient traction coefficient for systems such as automobiles that require high transmission torque capacity. .

An object of the present invention is to overcome the drawbacks of the conventional traction drive fluid and to provide a traction drive fluid having a particularly excellent traction coefficient.

[0006]

The inventors of the present invention have conducted extensive studies to develop a fluid for a traction drive having the above-mentioned excellent performance, and as a result, a novel cyclohexylmethyl having a specific structure that meets the purpose has been obtained. We have succeeded in developing silicone and discovered that a fluid for traction drive containing the silicone has excellent performance capable of satisfying the purpose, and completed the present invention.

That is, the gist of the present invention is, firstly, a cyclohexylmethyl silicone represented by the following chemical formula [I]:

[Chemical 5] (In the formula, R ^{1 to} R ⁸ each independently represent a methyl group or a cyclohexyl group. However, the content of the cyclohexyl group is 20 to 100% with respect to all the substituents, and at least one of R ^{1 to} R ⁶ is contained. Is a cyclohexyl group, and n is an integer of 0 to 3), and secondly, phenylmethyl silicone represented by the following chemical formula [II].

[Chemical 6] (In the formula, R ^{9 to} R ¹⁶ each independently represent a methyl group or a phenyl group. However, the content of the phenyl group is 20 to 100% with respect to all the substituents, and at least one of R ^{9 to} R ¹⁴ is Is a phenyl group, n is an integer of 0 to 3) at a temperature of 20 to 300 ° C. using a hydrogenation catalyst,
A cyclohexylmethyl silicone represented by the following chemical formula [I] exists in the above process for producing cyclohexylmethyl silicone, which comprises hydrogenating under a hydrogen pressure of atmospheric pressure to 200 kgf / cm ² · G.

[Chemical 7] (In the formula, R _{1 to} R ⁸ each independently represent a methyl group or a cyclohexyl group. However, the content of the cyclohexyl group is 20 to 75% with respect to all the substituents, and at least one of R ^{1 to} R ⁶ is contained. Is a cyclohexyl group, and n is 0
Indicates an integer of ˜2. ) Is contained in the fluid for traction drive.

Next, the present invention will be described in detail. In the cyclohexylmethyl silicone represented by the chemical formula [I] of the present invention, substituents R ^{1 to} R ⁸ are respectively bonded to silicon atoms forming a siloxane bond skeleton. ing. This substituent R ¹
To R ⁸ represents a methyl group or a cyclohexyl group each as the independent. The novel substance of the present invention has a ratio of cyclohexyl groups of 20 to 100% based on all substituents.
However, in the fluid actually used for the traction drive fluid of the present invention, the ratio of the cyclohexyl group is 20 relative to all the substituents in order to maintain the viscosity index in an appropriate range, as described in detail below. ~ 75%. Also R ¹ ~
At least one of R ⁶ is a cyclohexyl group.

In the cyclohexylmethyl silicone of the present invention, the traction coefficient can be improved by increasing the content of cyclohexyl group, but conversely, when the content is too large, the viscosity becomes high and the stirring resistance increases. This is a disadvantage because it causes a decrease in efficiency. Therefore, the cyclohexylmethyl silicone used as a traction drive fluid has a constraint that the substituents R ^{1 to} R ⁸ contain 20 to 75% of a cyclohexyl group, and at least one of the substituents R ^{1 to} R ⁶ is a cyclohexyl group. Other than the above, it can be appropriately selected from a methyl group and a cyclohexyl group according to the desired performance, but the content of the cyclohexyl group is preferably 35 to 65 with respect to all the substituents.
%. When the content of cyclohexyl group is less than 20%, the obtained traction coefficient is low, and when it is more than 75%, the viscosity is increased, the viscosity index is decreased, and the low temperature fluidity is deteriorated, which is not preferable as a traction drive fluid. When all of the substituents R ^{1 to} R ⁶ are methyl groups (trimethylsiloxy endblocking), the traction coefficient is low or the room temperature to low temperature even if the cyclohexyl group is contained in 20 to 75% of all the substituents. Therefore, a problem such as crystallization occurs, and the desired effect cannot be obtained as the traction drive fluid of the present invention.

The cyclohexylmethyl silicone of the formula [I], which is a novel substance of the present invention, has n of 0 to 3
, I.e., the total number of silicon atoms is 2, 3, 4 or 5, disiloxane, trisiloxane, tetrasiloxane, pentasiloxane skeleton. On the other hand, what is used as the traction drive fluid of the present invention is
The compounds are disiloxane, trisiloxane and tetrasiloxane, which are compounds of the chemical formula [I] where n is 0 to 2. When n is 3 or more, not only problems such as low temperature fluidity due to an increase in viscosity occur, but also solubility in other lubricants decreases, resulting in cloudiness and separation, which is not preferable.

Particularly preferably, cyclohexylmethyl silicone used in the fluid for traction drive of the present invention is specifically 1,1,3-tricyclohexyl-1,
3,3-trimethyldisiloxane, 1,1,5,5-tetracyclohexyl-1,3,3,5-tetramethyltrisiloxane, 1,1,3,5,5-pentacyclohexyl-1,3,5 -Trimethyltrisiloxane, 1,
3,5-Tricyclohexyl-1,1,3,5,5-pentamethyltrisiloxane, 1,1,7,7-tetracyclohexyl-1,3,3,5,5,7-hexamethyltetrasiloxane, etc. Is mentioned.

The cyclohexylmethylsilicone used in the traction drive fluid of the present invention may be a single compound, but it satisfies the above chemical formula [I], and the cyclohexyl group is 20 to 20 with respect to all the substituents. 7
It may be a mixture of several compounds having different bonding positions of a methyl group and a cyclohexyl group, and compounds having different siloxane bond chain lengths as long as they occupy 5% and n is 0 to 2.

The cyclohexylmethylsilicone of the present invention is not particularly limited in raw material and production method and can be obtained by various methods. Usually, commercially available methylphenylsilicone can be produced by hydrogenation. . Here, the methyl phenyl silicone as a raw material has a chemical formula [II]

[Chemical 8] (In the formula, R ^{9 to} R ¹⁶ each independently represents a methyl group or a phenyl group. However, the content of the phenyl group is 20 to 100% with respect to all the substituents, and at least one of R ^{9 to} R ¹⁴ is Is a phenyl group, and n represents an integer of 0 to 3.). However, as the raw material of cyclohexylmethyl silicone used in the fluid for traction drive of the present invention, those having 20 to 75% of phenyl groups and n of 0 to 2 among the above substituents, or those A mixture will be used.

The hydrogenation of the above methylphenyl silicone can be generally carried out in the presence of a catalyst, optionally adding a solvent and the like. As the catalyst, nickel, ruthenium, palladium, platinum, rhodium, iridium, copper,
What is generally known as a hydrogenation catalyst containing one or more metals such as chromium, molybdenum, cobalt and tungsten can be used. The amount of this catalyst added is not particularly limited, but is usually 0.1 to 100% by weight (metal amount is 0.1
-20% by weight), preferably 1-50% by weight (1-10% by weight as metal content). Examples of the solvent include n-pentane, n-hexane, heptane, octane, nonane, decane, dodecane and the like, and liquid saturated hydrocarbons such as cyclopentane, cyclohexane and methylcyclohexane.

This hydrogenation reaction is carried out in the temperature range of 20 to 300 ° C., preferably 60 to 200 ° C., and atmospheric pressure to 200 Kgf / cm ² · G, preferably ²⁰ to 1 like the ordinary hydrogenation reaction.
It can be carried out under a hydrogen pressure of 00 Kgf / cm ² · G. The time required for hydrogenation varies depending on the type of catalyst used, the amount used, the reaction conditions such as temperature and pressure, and cannot be specified unconditionally, but it is generally several minutes to 100 hours, usually 30 minutes to
It is about 50 hours, preferably about 1 to 24 hours. The hydrogenation may be carried out batchwise or continuously, and the catalyst may be used in any known catalyst bed format such as a suspension bed or a fixed bed.

When the cyclohexylmethyl silicone represented by the chemical formula [I] produced as described above is used as a fluid for a traction drive, if necessary,
Other lubricants can be added alone or in admixture. At this time, it is desirable that cyclohexylmethyl silicone is contained in an amount of at least 5% by weight, preferably 50% by weight or more. For other lubricants added,
There is no particular limitation, and commonly used mineral oil, synthetic oil, or other traction drive fluid can be used. These are desirable as the traction coefficient is higher,
It is necessary to pay sufficient attention to compatibility.

Further, the traction drive fluid which is the object of the present invention contains various additives such as an antioxidant, an antiwear agent, or a detergent dispersant in an amount of 0.05 to 0.05 depending on the application.
The property can be adjusted by adding about 10% by weight.

[0018]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 100 g of 1,3,3,5-tetramethyl-1,1,5,5-tetraphenyltrisiloxane as a raw material for 10 liter autoclave, 10% by weight of palladium / activated carbon catalyst 5
0 g and 500 ml of cyclohexane as a solvent were charged, and hydrogenation was carried out at a hydrogen pressure of 20 Kgf / cm ² · G and a reaction temperature of 100 ° C for 7 hours. After cooling, the catalyst was filtered off and the solvent was removed by a rotary evaporator.
100% hydrogenated 1,1,5,5-tetracyclohexyl-1,3,3,5-tetramethyltrisiloxane was obtained. The purity determined by hydrogen flame (FID) gas chromatography (GC) was almost 100%.

The measurement results and properties by instrumental analysis used for determining the structure of the obtained 1,1,5,5-tetracyclohexyl-1,3,3,5-tetramethyltrisiloxane are shown below.

Hydrogen nuclear magnetic resonance ( ¹ H-NMR) δ ppm −0.06 s, 6H (hydrogen of methyl group bonded to terminal Si) 0.03 s, 6H (bonded to central Si) 0.65 m, 4H (hydrogen attached to carbon bonded to Si of cyclohexyl group bonded to terminal Si) 1.20 br, 20H (to Si of cyclohexyl group) One hydrogen attached to non-bonded carbon) 1.72 br, 20H (the other hydrogen attached to carbon not bonded to Si in the cyclohexyl group)

Gas chromatography mass spectrometry (GC-
MS) m / z 508 (39) 425 (100) 356 (24) From the results of the above GC-MS, the molecular weight of the product was determined to be 508.

Elemental analysis value: C ₂₈ H ₅₆ O ₂ Si ₃ molecular weight (calculated value): 509 Actual value (%) C: 66.2; H: 11.0 Calculated value (%) C: 66.1; H 11.0 Density (25 ° C.): 0.984 g / cm ³ Kinematic viscosity at 40 ° C .: 95.4 cSt Kinematic viscosity at 100 ° C .: 9.84 cSt Viscosity index: 77 Pour point: −27.5 ° C.

The GC-MS of the product is shown as FIG.

Example 2 100 g of 1,3,5-trimethyl-1,1,3,5,5-pentaphenyltrisiloxane as a raw material for 10 liter autoclave, 10% by weight of palladium / activated carbon catalyst 50
g, 500 ml of solvent cyclohexane were charged, and the hydrogen pressure was 2
Hydrogenation was carried out at 5 Kgf / cm ² · G and a reaction temperature of 100 ° C. for 10 hours. After cooling, the catalyst was filtered off and the solvent was removed by a rotary evaporator. When the reaction solution was analyzed in the same manner as in Example 1, 1,1,3,5,5-pentacyclohexyl-1,1 having a 100% hydrogenated phenyl group as a raw material
It was 3,5-trimethyltrisiloxane, and its purity was found to be almost 100%. The measurement results and properties of this product by instrumental analysis are shown below.

Hydrogen nuclear magnetic resonance ( ¹ H-NMR) δ ppm −0.05 s, 6H (hydrogen of methyl group bonded to terminal Si) −0.02 s, 3H (bonded to central Si) 0.51 m, 1H (hydrogen attached to carbon bonded to Si of cyclohexyl group bonded to central Si) 0.66 m, 4H (to terminal Si) Hydrogen attached to Si-bonded carbon of cyclohexyl group) 1.20 br, 25H (One hydrogen attached to carbon not attached to Si of cyclohexyl group) 1.72 br, 25H (other hydrogen attached to carbon not bonded to Si of cyclohexyl group)

Gas chromatography mass spectrometry (GC-
MS) m / z 576 (100) 493 (2) 424 (15) From the results of the above GC-MS, the molecular weight of the product was determined to be 576.

Elemental analysis value: C ₃₃ H ₆₄ O ₂ Si ₃ molecular weight (calculated value): 577 measured value (%) C: 68.7; H: 11.1 calculated value (%) C: 68.7; H 11.1 Density (25 ° C.): 0.997 g / cm ³ Kinematic viscosity at 40 ° C .: 935 cSt Kinematic viscosity at 100 ° C .: 31.3 cSt Viscosity index: 26 Pour point: −5.0 ° C.

The GC-MS of the product is shown as FIG.

Example 3 1, 3, 3, 5, which is a raw material for 1 liter autoclave
5,7-Hexamethyl-1,1,7,7-tetraphenyltetrasiloxane 100 g, 10% by weight palladium /
50 g of activated carbon catalyst and 500 ml of cyclohexane as a solvent were charged, and hydrogen pressure was 20 Kgf / cm ² · G and reaction temperature was 100 ° C.
Hydrogenation was carried out for an hour. After cooling, the catalyst was filtered off and the solvent was removed by a rotary evaporator. When the reaction solution was analyzed in the same manner as in Example 1, the phenyl group of the raw material was found to be 100.
% Hydrogenated 1,1,7,7-tetracyclohexyl-1,3,3,5,5,7-hexamethyltetrasiloxane, the purity of which was found to be almost 100%. The measurement results and properties of this product by instrumental analysis are shown below.

Hydrogen nuclear magnetic resonance ( ¹ H-NMR) δ ppm −0.05 s, 6H (hydrogen of methyl group bonded to terminal Si) 0.05 s, 12H (bonded to Si other than terminal) 0.65 m, 4H (hydrogen attached to carbon bonded to Si in cyclohexyl group bonded to terminal Si) 1.20 br, 20H (Si in cyclohexyl group) One hydrogen attached to a carbon not bound to) 1.72 br, 20H (the other hydrogen attached to a carbon not bound to Si of a cyclohexyl group)

Gas chromatography mass spectrometry (GC-
MS) m / z 583 (26) 493 (100) 414 (22) From the results of the above GC-MS, the molecular weight of the product was measured to be 583.

Elemental analysis value: C ₃₀ H ₆₂ O ₃ Si ₄ Molecular weight (calculated value): 583 Measured value (%) C: 61.9; H: 10.7 Calculated value (%) C: 61.9; H 10.7 Density (25 ° C.): 0.990 g / cm ³ Kinematic viscosity at 40 ° C .: 205 cSt Kinematic viscosity at 100 ° C .: 16.8 cSt Viscosity index: 86 Pour point: −27.5 ° C.

The GC-MS of the product is shown as FIG.

Example 4 The traction coefficient and evaporation loss of the compounds obtained in Examples 1 to 3 were measured. The results are shown in Table 1. In addition, these evaluations were performed by the following methods.

Traction coefficient: 4 Driven shaft rotation number 1,000 rpm (2.09 m /
s), the slip ratio was 5% and the ratio of the transmitted close contact force to the normal load measured at a normal load of 114 Kgf was used. The oil temperature in the table shows the oil temperature at the time of measurement.

Evaporation loss: 1 by open beaker method
The evaluation was performed under the conditions of 60 ° C. and 24 hours.

Comparative Examples 1 and 2 The traction coefficient and the evaporation loss of the raw material methylphenyl silicone used in Examples 1 and 2 were measured in the same manner as in Example 4. The results are shown in Table 1. Moreover, these properties are shown below.

Sample of Comparative Example 1 Density (25 ° C.): 1.059 g / cm ³ Kinematic viscosity at 40 ° C .: 18.7 cSt Kinematic viscosity at 100 ° C .: 4.29 cSt Viscosity index: 141 Pour point: -40.0 ° C.

Sample of Comparative Example 2 Density (25 ° C.): 1.091 g / cm ³ Kinematic viscosity at 40 ° C .: 59.3 cSt Kinematic viscosity at 100 ° C .: 7.61 cSt Viscosity index: 88 Pour point: −20.0 ° C.

Comparative Example 3 1,1,1,3 as raw materials for 1 liter autoclave
3,5,5-Heptamethyl-5-phenyltrisiloxane 100 g, 10 wt% palladium / activated carbon catalyst 50
g, 500 ml of solvent cyclohexane were charged, and the hydrogen pressure was 2
Hydrogenation was carried out at 0 Kgf / cm ² · G and a reaction temperature of 100 ° C for 5 hours. After cooling, the catalyst was filtered off and the solvent was removed by a rotary evaporator. When the reaction solution was analyzed in the same manner as in Example 1, it was found that the starting phenyl group was 100% hydrogenated 1-cyclohexyl-1,1,3,3,5,5,5-heptamethyltrisiloxane. The purity was found to be almost 100%. The properties are shown below.

Density (25 ° C.): 0.941 g / cm ³ Kinematic viscosity at 40 ° C .: 42.8 cSt Kinematic viscosity at 100 ° C .: 10.1 cSt Viscosity index: 234 Pour point: −45.0 ° C.

Table 1 shows the measurement results of the traction coefficient and the evaporation loss performed in the same manner as in Example 4.

Comparative Example 4 1 l of autoclave was charged with trimethylsiloxy end-blocked methylphenyl silicone (density 0.990 g / cm3).
³ (25 ° C), kinematic viscosity 8.98 cSt (40 ° C), 2.
74 cSt (100 ° C), viscosity index 159, pour point -6
0.0 g, phenyl group content 28%) 100 g, 10 wt% palladium / activated carbon catalyst 50 g, and cyclohexane 500 ml as a solvent were charged, and hydrogenation was carried out at a hydrogen pressure of 25 Kgf / cm ² · G and a reaction temperature of 100 ° C. for 7 hours. went. After cooling, the catalyst was filtered off and the solvent was removed by a rotary evaporator. As a result of ¹ H-NMR analysis, the hydrogenation rate was 100.
%Met. The properties of this product are shown below.

Density (25 ° C.): 0.938 g / cm ³ Kinematic viscosity at 40 ° C .: 32.4 cSt Kinematic viscosity at 100 ° C .: 5.53 cSt Viscosity index: 107 Pour point: −45.0 ° C.

When this compound was stored in a low temperature room kept at 0 ° C., it completely crystallized in 24 hours. After that, the temperature was returned to room temperature, and even if it was left to stand again, it was not liquefied and crystals were still formed.

The traction coefficient and the evaporation loss of this product were evaluated in the same manner as in Example 4. The results are shown in Table 1.

Comparative Example 5 Trimethylsiloxy end-capped methylphenyl silicone (density 1.066 g / cm 3) was used as a raw material in 1 l of autoclave.
³ (25 ° C), kinematic viscosity 215 cSt (40 ° C), 42.
6 cSt (100 ° C.), viscosity index 254, pour point -5
0.0 g, phenyl group content 27%) 100 g, 10 wt% palladium / activated carbon catalyst 50 g, and cyclohexane 500 ml as a solvent were charged, and hydrogenation was carried out at a hydrogen pressure of 25 Kgf / cm ² · G and a reaction temperature of 100 ° C. for 7 hours. went. After cooling, the catalyst was filtered off and the solvent was removed by a rotary evaporator. As a result of performing the same analysis as in Comparative Example 4, the hydrogenation rate of the reaction liquid was 100%. The properties of this product are shown below.

Density (25 ° C.): 1.012 g / cm ³ Kinematic viscosity at 40 ° C .: 1204 cSt Kinematic viscosity at 100 ° C .: 123 cSt Viscosity index: 205 Pour point: −27.5 ° C.

Table 1 shows the measurement results of the traction coefficient and the evaporation loss performed in the same manner as in Example 4.

[0051]

[Table 1]

From the above results, the traction drive fluids of the present invention (Examples 1 to 3) were the methylphenyl silicones of Comparative Examples 1 and 2, the trimethylsiloxy end-capped cyclohexylmethyl silicone of Comparative Examples 4 and 5, and the present invention. It can be seen that the traction coefficient is remarkably excellent as compared with any of the cyclohexylmethyl silicones of Comparative Example 3 having a smaller cyclohexyl group content than the above. Contrary to this, Comparative Examples 1 to 5 have low traction coefficients, and it is difficult to meet the recent demand for high transmission torque capacity.

[0053]

The traction drive fluid of the present invention has an excellent traction coefficient and evaporating property, and has a viscosity, a viscosity index and a pour point which are suitable as a traction drive fluid, so that it is always stable and has high power transmission. In addition to being able to exert its ability, it is possible to reduce the size and weight of the device and extend its service life. Therefore, it can be suitably used for a device having a large torque capacity such as a continuously variable transmission for automobiles and severe operating conditions.

Cyclohexylmethyl silicone, which is a novel substance of the present invention, has a high traction coefficient and is useful as a fluid for traction drive.

[Brief description of drawings]

1 is a GC-MS graph of the product of Example 1. FIG.

2 is a GC-MS graph of the product of Example 2. FIG.

3 is a GC-MS graph of the product of Example 3. FIG.

Front page continuation (72) Inventor Toshio Shimizu 1134-2, Gongendo, Satte City, Saitama Cosmo Research Institute Co., Ltd. (72) Haruhiko Takeya, 1134-2, Gongendo, Satte City, Saitama Prefecture Sumo Research Institute R & D Center (72) Inventor Hiroshi Munakata 1134-2, Gongendo, Satte City, Saitama Prefecture Cosmo Research Institute R & D Center (72) Inventor, Hiroshi Aoyama 1134, Gongendo, Satte City, Saitama Prefecture 2 Cosmo Research Institute Co., Ltd. Research and Development Center

Claims (3)

[Claims] 1. A cyclohexylmethyl silicone represented by the following chemical formula [I]: (In the formula, R ^{1 to} R ⁸ each independently represent a methyl group or a cyclohexyl group. However, the content of the cyclohexyl group is 20 to 100% with respect to all the substituents, and at least one of R ^{1 to} R ⁶ is contained. Is a cyclohexyl group, and n is an integer of 0 to 3.). 2. Phenylmethyl silicone represented by the following chemical formula [II]: (In the formula, R ^{9 to} R ¹⁶ each independently represent a methyl group or a phenyl group. However, the content of the phenyl group is 20 to 100% with respect to all the substituents, and at least one of R ^{9 to} R ¹⁴ is Is a phenyl group, n is an integer of 0 to 3) at a temperature of 20 to 300 ° C. using a hydrogenation catalyst,
Cyclohexylmethyl silicone represented by the following chemical formula [I], which comprises hydrogenating under a hydrogen pressure of atmospheric pressure to 200 kgf / cm ² · G. (In the formula, R ^{1 to} R ⁸ each independently represent a methyl group or a cyclohexyl group. However, the content of the cyclohexyl group is 20 to 100% with respect to all the substituents, and at least one of R ^{1 to} R ⁶ is contained. Is a cyclohexyl group, and n is an integer of 0 to 3.). 3. A cyclohexylmethyl silicone represented by the following chemical formula [I]: (In the formula, R ^{1 to} R ⁸ each independently represent a methyl group or a cyclohexyl group. However, the content of the cyclohexyl group is 20 to 75% with respect to all the substituents, and at least one of R ^{1 to} R ⁶ is contained. Is a cyclohexyl group, and n is 0
Indicates an integer of ˜2. ) Is contained in the fluid for traction drive.