JPS6086197A - Fluid for traction driving - Google Patents

Abstract

PURPOSE:A novel fluid for traction driving, consisting of a hydrocarbon having gem type dimethyl group and cyclohexyl group (which may have a substituted alkyl group), and having a high traction coefficient. CONSTITUTION:A fluid for traction driving, consisting of (A) a hydrocarbon expressed by formula I (one of R1-R4 is 4-8C branched alkyl, and the rest are H or methyl), e.g. expressed by formula II, etc. and/or (B) a hydrocarbon expressed by formula III (one of R5-R10 is 4-8C branched alkyl, and the rest are H or methyl), e.g. a mixture of hydrocarbons expressed by formulas IV with V. tert-Butyl, isobutyl, isopentyl and neopentyl groups, etc. are suitable to the branched alkyl groups in the above-mentioned formulas.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a traction drive fluid. More specifically, the present invention relates to a novel traction drive fluid having a high traction coefficient and consisting of a single hydrocarbon or a mixture thereof represented by a specific chemical formula.

The operating principle of a traction drive device is to press a driven rotary body against a driving rotary body, rotate the driven rotary body by point contact or line contact friction between the two rotary bodies, and transmit power.

Traction drive fluid (
(hereinafter abbreviated as fluid) is constantly supplied. When there is no load, this fluid lubricates both rotating bodies, and when it is loaded, it receives a pressure of 200,000 to 400,000 psi (1,40,000 to 30,000 psi, causing instantaneous displacement between molecules. It becomes a state that is difficult to occur and becomes a medium for power transmission.

The power transmission performance of a fluid is generally expressed by a traction coefficient f, which is defined as the ratio of a tangential force (or traction force) Ft and a normal load P, as shown in FIG.

L −F+ / Pn...Song......Tap (1) Transforming equation (1), we get F, = f, XP
n river...Use...(2) is obtained, and from this equation the following is understood. That is, when the normal load Pfl is set to a value of 1, the tangential force increases as the fluid with a higher coefficient is used, but the device can be made smaller and lighter.

If the required tangential force F is set to a value, the normal load Pn can be lowered as the fluid with a higher traction coefficient is used, and therefore the rolling fatigue wear of the rotating body can be reduced. Efforts are thus being made to improve the traction coefficient even slightly.

So far, such fluids include naphthenic mineral oil, hydrogenated polyolefin, dicyclohexylalkane, etc.
Over 0 types of products have been submitted, and although it has been empirically recognized that some of these products exhibit high traction coefficients, they are still not fully satisfactory.

The mechanism of fluid action is considered to be so-called elastohydrodynamic lubrication, starting with Eyring's viscosity theory (1936) and Gubrln (1949) T Dow+son.
(1960) + Maxwell's viscoelastic model (19
68), various theories have been developed and it appears that a theoretical system has been completed. However, it is not clear why the aforementioned fluids provide a high traction coefficient.

The inventors considered the behavior of the molecules that make up the fluid under load and achieved the molecular design necessary to increase the traction coefficient of the fluid.

When a group of fluid molecules gradually enters a narrow space from the opening A to the contact part B in the apparatus shown in FIG. 1, the molecules come closer and their density increases. It is preferable that no molecules fall out of the group during this approach.

If many molecules fall off, the oil film that forms becomes thinner and there is a risk of damage due to dry friction. Molecules do not have the force to try to enter themselves, but simply follow the movement of the fluid, so in order to avoid falling out, it is necessary for the molecules to become caught or entangled in some way. Moreover,
In order to maintain this favorable state, it is preferred that the molecules are not deformed by external forces.

Next, the molecules entering the contact area are given energy by pressure and side-slip forces, generating heat and intensifying molecular motion. Even under such conditions, each molecule is preferably in an immobile state. If there is a shift in the arrangement of the molecules at this time, this indicates that the material is a so-called fluid, and cannot be used as a power transmission medium. For media molecules to exhibit this behavior,
After all, entanglement will occur if the molecules catch on each other, and it must have enough rigidity to maintain this state.

Furthermore, since the molecular group is released from pressure after passing through the contact area 9, the molecular spacing quickly widens and the molecules must be dispersed into individual molecules to restore the original fluid state. If the molecules remain aggregated, the viscosity of the fluid will increase and normal operation will be hindered.

In order for fluid molecules to exhibit such behavior, it is desirable that the following conditions be met.

(1) The shape of the molecule is uneven and curved. Holes are formed in such molecules, and when the molecules come close to each other, they can fit, get caught, overlap, or become entangled.

(2) The molecule has rigidity. This is because the preferred three-dimensional structure described in the previous section must not change even when subjected to external pressure.

(3) The molecule is thick. Forms a thick oil film under load to reduce dry friction and wear on both rotating bodies.

(4) The molecule is short. It becomes difficult for long-chain molecules to quickly disperse after passing the point of contact between the two wheels.

Furthermore, drawbacks such as excessively high viscosity and excessive power loss are also unavoidable. In addition, long-chain molecules tend to be deformed due to the rotation of σ bonds between atoms, resulting in insufficient rigidity.

(5) The molecule should be mechanically, thermally and chemically stable.

(6) From a practical standpoint, it can be obtained inexpensively and in large quantities.

Among the above requirements, (1) and (2) are particularly important and can be satisfied by a hydrocarbon having a cyclohexyl group and a branched alkyl group substituted with a cyclohexyl group.

The gem type (dimedimethyl gem) means "pair"), the remaining two bonds of the central carbon atom have a valence angle of 109°28', and this angle is unique to the atom. It is a thing, and it hardly changes even if external forces are applied to it. Therefore, determine the direction of the atomic group bonded to this,
Forms a bent molecule, creating the necessary vacancies.

The cyclic structure of the cyclohexyl group has strong rigidity and is not deformed by external force. A cyclohexyl group is usually synthesized by hydrogenation of a benzene ring, but its six carbon atoms are bonded in a so-called chair shape, and two hydrogen atoms are bonded to each of these, making the benzene ring planar. The molecules have a bulge and are more three-dimensional compared to the previous one.

A branched alkyl group substituted with a cyclohexyl group enlarges the cyclohexyl group, enlarges the pores in the molecule, and also enlarges the entire molecule.

An object of the present invention is to provide a traction fluid that has a high traction coefficient and has excellent characteristics as other traction fluids.

The objects of the present invention are achieved by the following Tracrayon fluid.

General formula (wherein, one group of R1+ R2+ R3 and R4 is a branched alkyl group having 4 to 8 carbon atoms, and the other groups are hydrogen or methyl groups) or general formula (wherein,
R1+ R6* R? r R8+ g, and RIG
One of the groups is a branched alkyl group having 4 to 8 carbon atoms, and the other groups are hydrogen or methyl groups. Traction drive fluid.

In the hydrocarbons represented by general formulas (1) and (II), the branched alkyl group having 4 to 8 carbon atoms is t
-butyl group, isobutyl group, isopentyl group.

A neopentyl group is suitable. A tertiary alkyl group is particularly preferred. For example, a small alkyl group such as an isopropyl group is not preferred because it has little effect on enlarging the molecule. In addition, if the number of carbon atoms is larger than 8, for example, an inalkyl group, the viscosity becomes too thick, which is not preferable.

In the hydrocarbons represented by general formulas (I) and (II), rotation of the σ bond connecting the central carbon atom and the cyclohexyl group deforms the molecule, but the steric structure of the two gem-type methyl groups and the cyclohexyl group As the disorder occurs, the cells become fixed and maintain a rigid cavity and rigidity within the molecule.

The traction drive fluid of the present invention has the general formula (1)
Alternatively, the hydrocarbon represented by (It) may be produced from one type of hydrocarbon, or may be produced from a mixture of two or more types. Also,
It may also be synthesized using a mixture of aromatic hydrocarbons as a starting material.

The first step in producing the hydrocarbon used as the traction drive fluid is to add a vinyl group-substituted aromatic hydrocarbon to an alkyl group-substituted aromatic hydrocarbon in the presence of an acid catalyst, or to add a halogen to an aromatic hydrocarbon. This is a Friedel-Krach reaction in which an alkyl group-substituted carbon is reacted with an acid catalyst.

To give a specific example, in an alkyl group-substituted benzene such as t-butylbenzene or isopentylbenzene, an inpropenylbenzene such as α-methylstyrene or isopropenyltoluene is added with an acid catalyst such as a protonic acid or a Lewis acid. Add. In the first step, it is necessary to pay attention to the following points in order to obtain a molecule suitable for the purpose in high yield.

(1) In order to obtain a hydrocarbon oil with a low pour point, the general formula (1
) or (II). This is because if a single compound is made, its melting point will be high and in severe cases there is a risk of crystallization.

(2) Since α-methylstyrenes themselves tend to form into 2@1 units, it is necessary to prevent this.

(3) The production of resinous substances due to polymerization reactions must be avoided as much as possible.

Therefore, it is preferable to synthesize under the following conditions.

Using an alkyl-substituted aromatic hydrocarbon and a vinyl group-substituted aromatic hydrocarbon or an aromatic hydrocarbon and a halogenated alkyl group-substituted aromatic hydrocarbon at a molar ratio of 5=1 to 10:1,
The reaction is carried out at 0 to 15°C using 20 to 25% by weight of sulfuric acid based on the aromatic hydrocarbon as a catalyst.

Sulfuric acid as a catalyst preferably has a concentration of about 80%. After mixing the aromatic hydrocarbon and sulfuric acid, it is desirable to add the vinyl group-substituted aromatic hydrocarbon or the halogenated alkyl group-substituted aromatic hydrocarbon over as much time as possible, and to stir as vigorously as possible during the synthesis.

In addition, the degree of progress of the reaction is 12, gas chromatography,
It is desirable to carry out the synthesis while making judgments using infrared spectroscopic analysis.

In the second step, nuclear hydrogen is added to the aromatic hydrocarbon obtained in the first step.

Nuclear hydrogenation catalysts include nickel, nickel oxide, nickel-diatomaceous earth, Raney nickel, nickel-copper, platinum, platinum oxide, platinum-lithium-alumina, Logicomu activated carbon, palladium, cobalt, Raney cobalt, ruthenium, tungsten sulfide-nickel sulfide-alumina. Known aromatic nuclear hydrogenation catalysts such as
Nuclear hydrogenation can be achieved by contacting with a catalyst at temperatures below 250°C. In this nuclear hydrogenation, it is desirable to reduce the residual rate of aromatic nuclei to 2% or less. Note that this hydrogenation reaction may be carried out either batchwise or continuously.

Known additives, such as 2,6-tert-butyl para-cresol, ditheophosphate, etc., are added to the fluid thus obtained for the purpose of improving properties such as oxidation stability, corrosion prevention, rust prevention, and antifoaming properties. , a known thickener, etc. can be added as necessary. Further, for the purpose of adjusting the viscosity, the traction drive fluid and its components, such as conventionally known hydrocarbons, esters, etc., can be mixed and homogenized in any proportion.

The present invention will be explained in more detail below using Examples and Comparative Examples.

Example 1 A four-loop flask with a capacity of 21 ft equipped with a stirrer, thermometer, oxygen gas blowing tube, and pressure adjustment cock was set on a cooling path, and 10 moles (1342 g) of t-butylbenzene was added.
) Then, 300 g of 80% sulfuric acid was gradually added and cooled to below 15° C. while stirring.

To this, 1 mol (118.2 g) of α-methylstyrene was added dropwise over about 1 hr. The reaction was completed by stirring for 2 hours while keeping the temperature below 15°C. When the contents are allowed to stand still, they will separate into two layers, an upper and a lower layer, so separate and collect only the upper layer.
Neutralize with % caustic soda water and wash with water to make it neutral. The mixture was left to stand and water was sufficiently removed, and unreacted substances were separated using a separately prepared hydraulic distillation apparatus under conditions of 3 mHg and 150°C. Then, the following two benzene ring compound was distilled out under the conditions of 10 TnXHg and 200°C. This was used as a hydrogenation raw material. The yield was about 50% of theory. Its chemical structural formula was then obtained by adding nuclear hydrogen to an aromatic hydrocarbon as shown below.

In an autoclave with a capacity of 2 kg, add 30 kg of the 2-ring compound obtained above.
0- and 300 Tnl of cyclohexane were taken, stirred well, and then Raney nickel 209 was added.

Heating was started at an initial pressure of 30 Kv'ctd G, and after confirming that the hydrogen absorption rate and temperature did not rise significantly at 150°C, the reaction temperature was increased to 170°C and at the same time the hydrogen pressure was increased to 70°C.
I raised it to Ky'crtt G. As the hydrogenation reaction progresses, the pressure decreases, so when it drops to 60 K5]d G, hydrogen gas is again pressurized and the pressure is reduced to 7Q K (icr/l).
G 1151. Repeat this operation for about 2 hours.
After no pressure drop was observed at r, the reaction temperature was increased to 200
The reaction was completed by raising the temperature to 1 hr and maintaining the temperature at 1 hr. Next, the hydrogen gas in the autoclave was released and replaced with nitrogen gas, the autoclave was opened, the contents were taken out, filtered, and cyclohexane was removed by distillation from the F liquid, and then placed in a vacuum dryer for 70 minutes. After 5 hours under the conditions of .degree. C. and 1 mHg, the desired product from which cyclohexane had been completely removed was obtained. The hydrogenation rate was 99%. Its traction coefficient and other general properties are as shown in Table 1. It had a high traction coefficient and other properties such as viscosity were suitable as a traction drive fluid.

Example 2 At the end of the condensation reaction of Example 1, the residue after distilling off the two-ring compound was a pale yellow viscous oil, and the yield was about 1/3 of that of the two-ring compound. According to gas chromatography and infrared spectroscopy it is a 3-ring compound.

This was hydrogenated using the same method and conditions as Example 1,
The following hydrocarbons were obtained. The hydrogenation rate was 98.5%. Note that the weight ratio of (to) and hood was approximately 2:1.

The traction coefficient and other general properties are as shown in Table 1, and it had a high traction coefficient.

CH3CH3 〒H.

Example 3 The hydrocarbons obtained in Examples 1 and 2 both have a high traction coefficient, and one has a low viscosity.
It is a fluid with extremely high viscosity. Therefore, by mixing these three in any proportion, it is possible to produce various grades of fluids with high traction coefficients.
We can meet the demands of all types of equipment.

In this example, 4 volumes of the hydrocarbon of Example 1 and 1 volume of the hydrocarbon of Example 2 were mixed to produce a traction drive fluid. The traction coefficient and other general properties were as shown in Table 1.

Example 4 Synthesis using mixed alkylbenzene as a raw material The same method and conditions as in Example 1 were carried out using a mixture of alkylbenzenes mainly having tertiary alkyl groups whose side chains have 4 to 8 carbon atoms and α-methylstyrene as raw materials. When synthesized under the following procedure, aromatic hydrocarbons in which α-methylstyrene was added to each alkylbenzene were obtained. The yield was about 40% of theory. These mixtures were subsequently subjected to nuclear hydrogenation without fractionation. Hydrogenation was carried out in exactly the same manner and under the same conditions as in Example 1.

The addition of nuclear hydrogen changed the color from pale yellow to a clear, colorless hydrocarbon oil. The hydrogenation rate was about 98.5%.

The traction coefficient and other general properties are as shown in Table 1, and the traction coefficient and other general properties are those of Example 3.
fluid.

Comparative Example 1 Using 1-propylbenzene and α-methylstyrene as raw materials, an addition reaction was carried out under exactly the same method and conditions as in Example 1, followed by hydrogenation, to obtain the compound described at the beginning. Its general properties are shown in Table 2.

The traction coefficient was 0.082.

Comparative Example 2 An addition reaction was carried out using n-buflubenzene and α-methersterene as raw materials in exactly the same manner and under the same conditions as in Example 1, followed by hydrogenation to obtain the compound described at the beginning. Its general properties are shown in Table 2. Its traction coefficient was o, oso.

Comparative Example 3 Using m-xylene and styrene as raw materials, an addition reaction and then a hydrogenation reaction were carried out in exactly the same manner and under the same conditions as in Example 1 to obtain the synchlohexyl compound shown at the beginning.

The yield was about 60% of the theoretical value, and the hydrogenation rate was 99.0%. Its general properties are shown in Table 2.

Comparative Example 4 Table 2 shows the properties of a hydrogenated α-methylstyrene linear dimer, which is recognized to have the highest traction coefficient among traction fluids currently on the market.

As described above, the traction drive fluid of the present invention is
It has a higher Tracrayon coefficient than conventional products, and a desired viscosity can be obtained by mixing two or more of them. Therefore, it is possible to provide traction drive fluid for use in all types of equipment.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an aspect of the Trakunyon drive. Pfi: Normal load FI: Tangential force A: Opening B: Contact C: Input side D = Output side Fig. 1

Claims (1)

[Scope of Claims] General formula (wherein, one group among R, , R, , R, and R4 is a branched alkyl group having 4 to 8 carbon atoms, and the other groups are hydrogen or methyl groups. ) or the general formula (wherein R1
1r R6r R? r R,l R11 and R,+
1 is a branched alkyl group having 4 to 8 carbon atoms, and the other groups are hydrogen or methyl groups. Traction drive fluid.