JPH0631374B2 - Fluid for Traction - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a traction fluid, more specifically, a diester or derivative thereof having two cyclohexyl rings and a branched polybutene as a base oil. The present invention relates to a blended traction fluid.

(Prior Art) In automobiles or industrial machines, a traction drive power transmission device that transmits power to a driven part by a traction drive mechanism has been drawing attention, and research and development have been actively promoted in recent years. The traction drive mechanism is a power transmission mechanism utilizing rolling friction and the like, which does not use gears as in the conventional case, so that vibration and noise are reduced and high-speed gear shifting can be performed very smoothly. In the automobile industry, improving fuel efficiency of automobiles has become an important issue, but if a traction drive is applied to the transmission of the automobile and continuously variable transmission is performed, it is possible to always operate in the maximum fuel consumption range of the engine. It is said that fuel consumption can be reduced by 20% or more. Recent research achievements include development of materials with high fatigue strength and theoretical analysis of traction,
Regarding traction fluids, the correlation function of the traction coefficient at the molecular structure level of the component is gradually being clarified. Here, the traction coefficient means the contact portions of the rotating bodies that are in contact with each other in the rolling friction type power transmission device,
It is defined as the ratio of the traction force generated by slippage to the normal load.

Traction fluid is a lubricating oil with a high traction coefficient
Must have a naphthene ring in its molecular structure
It has been confirmed that the product exhibits high performance, and it is a commercial product.
As for Monsanto's "Sant truck Is widely known
Has been. As a traction fluid with a naphthene ring
Japanese Patent Publication No. 47-35763 discloses di (cyclohexyl) acetone.
Rucan or dicyclohexane are disclosed. this
The patent states that the alkane compound is perhydrogenated (alpha
-Methyl) styrene polymer or hydrindane compound
The traction coefficient of the fluid containing
To the effect. Further, JP-A-59-191797
Contains an ester compound having a naphthene ring.
Traction fluids are disclosed and cyclohexyl
Dicarboxylic acid dicyclohexyl ester or phthalate
By aromatic nucleus hydrogenation of acid dicyclohexyl ester
The resulting ester is preferred as a traction fluid
is doing.

(Problems to be solved by the invention) As described above, in the automobile industry in recent years, development of a continuously variable transmission has been promoted.
Although actively propelled, the transmission is
The higher the traction coefficient, the larger the allowable transmission force with the same device.
Because it is possible to reduce the size of the entire device,
Because it can reduce the amount of exhaust gas that causes pollution problems
A fluid having a traction coefficient as high as possible is desired. Shi
On the other hand, it has the highest performance as a commercially available traction fluid.
Beloved Santo Truck Is such a traction
When used as a drive unit, the traction coefficient is satisfactory.
The problem that the required performance is not obtained and the price is high
There is. In addition, the tiger proposed in Japanese Patent Publication No. 46-35763
Santo Truck Or similar substances
Since it is a single component, there are problems with performance and price as well.
is there.

(Means for Solving the Problems) The inventors of the present invention have conducted diligent research to obtain a relatively inexpensive traction fluid having a high traction coefficient, and as a result, a diester having two cyclohexyl rings or a diester thereof The present invention has been completed by confirming that a base oil fluid having high performance can be economically provided by blending a specific amount of a branched polybutene with the derivative.

The present invention has the general formula [In the formula, A ′ is an ester bond of —COO— or —OOC—, n is 1 to 6, R ₁ is a hydrogen atom, and the number of carbon atoms is 1
1 to 2 selected from an alkyl group of 8 to 8 and R ₂ is 1 or 2 selected from an alkyl group having 1 to 3 carbon atoms] has a branch in the diester or derivative thereof. The present invention relates to a traction fluid containing 0.1 to 70% by weight of polybutene.

A first object of the present invention is to provide a traction fluid having a high traction coefficient and excellent performance. A second object of the present invention is to provide a traction fluid that is economical, readily available and easily applied to the device.

The traction fluid of the present invention is a mixture of a diester or its derivative as an A component, which is composed of a two-component base oil, and a specific amount of a branched polybutene as a B component.

The component A of the present invention is a diester having two cyclohexyl rings or a derivative thereof and has the above structural formula. A'of the ester bond is -COO- or -O
N of repeating unit of gem-dialkyl structure which is OC-
Is 1 to 6, particularly preferably 1 to 3. When n is 0, the traction coefficient is low, and when n is 7 or more, the viscosity is high, which is not preferable. This diester or its derivative is produced by the following method and has the following properties.
Viscosity at 40 ℃ is 20 ~ 50cst, especially 24 ~ 30cst, 10
It is preferably 4 to 10 cst, particularly 4 to 6 cst at 0 ° C. The viscosity index is preferably in the range of 40 to 100, particularly 50 to 80.

The component A can be manufactured by the following method.
The component A can be obtained by an esterification reaction between a glycol compound and a cyclohexanecarboxylic acid compound. 1 gem-dialkyl structure as glycol compound
Those having up to 6 are selected, neopentyl glycol being preferred. The cyclohexanecarboxylic acid compound has an alkyl group having 1 to 8 carbon atoms in addition to cyclohexanecarboxylic acid, and examples thereof include methylcyclohexanecarboxylic acid and ethylcyclohexanecarboxylic acid. Particularly preferred is cyclohexanecarboxylic acid. The esterification reaction is carried out in the vicinity of a reaction equivalent amount or under an acid excess condition. However, in the former case, there is a problem that a catalyst is required and a by-product of monoalcohol is generated, so it is preferable to adopt the acid excess condition. . That is,
The acid is reacted in an amount of 2 to 5 times mol (particularly preferably 2.5 to 4 times mol) with respect to 1 mol of the glycol compound. Reaction temperature is about 1
50 ~ 250 ℃, preferably 170 ~ 230 ℃, the reaction time is 10
~ 40 hours, preferably 15-25 hours. The reaction pressure may be increased or decreased, but normal pressure is preferable in terms of reaction operation. Under this condition, excess acid acts as a catalyst. Further, an appropriate amount of alkylbenzene such as xylene and toluene can be added as a solvent. The reaction and temperature can be easily controlled by adding a solvent. With the progress of the reaction, the produced water evaporates, but the reaction ends when this water becomes twice the mole of the alcohol. Excess acid is neutralized with an aqueous alkali solution and washed with water to remove it. If the acid is difficult to remove by washing with an alkali, the acid is used in a molar amount of 2 to 2.5 times that of the alcohol and the reaction is carried out using a catalyst. As the catalyst, phosphoric acid, paratoluenesulfonic acid, sulfuric acid or the like can be used, but phosphoric acid is most preferably used from the viewpoint of increasing the reaction rate and increasing the ester yield. The diester compound of the present invention is finally obtained by distilling the reaction product under reduced pressure to allow water and a solvent to flow out. The component A of the present invention can also be produced by esterification of a cyclohexanol compound and a dicarboxylic acid having a quaternary carbon. In this case, cyclohexanol or methylcyclohexanol may be used as the cyclohexanol compound, and neopentyldicarboxylic acid or the like may be used as the dicarboxylic acid.

Polybutene as the B component has a quaternary carbon atom or a tertiary carbon atom in its main chain, and is a polymer of alpha-olefin having 3 to 5 carbon atoms and its hydrogenated product. Preferred are polybutene (including polyisobutylene) and hydrogenated products thereof. Polyisobutylene can be represented by the following structural formula.

The hydrogenated product is represented by the following structural formula.

However, the degree of polymerization n is 6 to 200.

As polybutene and polyisobutylene, commercially available products may be used, but they can be produced by polymerizing by a known method. The hydrogenated product is produced by reacting polyisobutylene or the like in the presence of hydrogen. Particularly preferred polybutenes are those having a molecular weight in the range of 500 to 10,000, more preferably 900 to 5,000. The molecular weight can be adjusted by decomposing high molecular weight polybutene, mixing low molecular weight polybutene, and the like. In addition, there is an alpha-olefin copolymer (OCP) as a high molecular polymer whose production material is partially the same as that of polyalpha-olefin, but this OCP is not suitable for use as the component B of the present invention. The reason is that OCP is obtained by polymerization of two or more alpha-olefins and has a structure in which they are randomly linked, and is not a regular gem-dimethyl type structure such as polybutene of the present invention.

In the present invention, the component A, such as neopentyl glycol cyclohexanecarboxylic acid diester, has a traction coefficient of 0.100 to 0.104, and the component B, such as polybutene, has a traction coefficient of 0.075 to 0.085.

Since the A component of the present invention has a high traction coefficient, even if the A component is applied to the traction drive device alone, high performance can be exhibited. However, a more preferable traction fluid can be obtained by adding 0.1 to 70% by weight of polybutene as the component B to the component A. That is, although the B component has a lower traction coefficient than the A component, the gem-dimethyl group of the B component exerts a traction coefficient improving action by a synergistic effect with the cyclohexyl ring of the A component, and is inexpensive and has excellent viscosity characteristics. Therefore, by adding 0.1 to 70% by weight of the component B to the component A, a traction fluid can be economically obtained without lowering the traction coefficient.

Various additives can be added to the traction fluid of the present invention depending on the application. That is, if the traction device is subject to high temperature and heavy load, an antioxidant,
About 0.01 to 5% by weight of one or more additives such as antiwear agents or antirust agents can be blended. Similarly, when a high viscosity index is required, a known viscosity index improver may be added in an amount of 1 to 10% by weight. However, the use of polymethacrylate or olefin copolymer lowers the traction coefficient, so the addition amount of these must be 4% by weight or less.

In the present invention, the traction fluid refers to a fluid used in a device that transmits rotational torque by point contact or line contact, and a transmission device having a structure similar to these. The traction fluid of the present invention has a higher traction coefficient than conventionally known fluids, and has a traction coefficient 1 to 5% higher than that of a conventional product, depending on properties such as viscosity. Therefore, the traction fluid of the present invention is preferably used not only for internal combustion engines such as small passenger cars, but also for relatively low power transmission devices such as spinning machines and food manufacturing machines, as well as traction drive devices such as high power industrial machines. Can be applied.

(Operation) The traction fluid of the present invention has a remarkably excellent traction coefficient as compared with known fluids, but it is still not completely clarified as to why it can exhibit a high traction coefficient. Not not. Basically, it is considered to be based on the unique molecular structure of the traction fluid of the present invention.

First, the traction fluid of the present invention is a diester, which has two cyclohexyl rings in the compound molecule, and since they are ester-bonded, interdipole force acts between the molecules. It is considered that this inter-dipole force changes the fluid to a stable glass state under the high load condition of the traction device and increases the anti-shear force.
Furthermore, the traction fluid of the present invention has a gem-dialkyl type quaternary carbon in both the A component and the B component, and the A component is intramolecular because it is bonded to two cyclohexyl rings through a methoxycarbonyl bond. It has a structure that makes it difficult to rotate. Therefore, it is considered that when the traction device has a high load, the cyclohexyl ring and the gem-dialkyl portion of the quaternary carbon mesh firmly like a gear, and when released from the load, they quickly disengage and fluidize.

(Examples) Examples 1 to 11 Neopentyl glycol cyclohexanecarboxylic acid diesters of the present invention were synthesized by the following method.

1 mol of neopentyl glycol is mixed with 3 times mol of cyclohexanecarboxylic acid and reacted at a reaction temperature of 200 ° C. and normal pressure for 20 hours. Since there is an excess of acid, no catalyst is used and xylene is used as a solvent. The reaction ends when the water evaporated along with the reaction becomes twice the mole of alcohol. Wash off excess acid with alkali (caustic soda),
Rinse with water until neutral. By distilling the reaction product under reduced pressure, water and xylene are distilled off to isolate the diester of the present invention.

The diester thus produced then has an average molecular weight of 420 to 2
The traction coefficient was determined by blending 350 polybutenes. The conditions for measuring the traction coefficient are as follows.

Measuring device: Soda 4-roller traction tester Test conditions: Hot water temperature 20 ° C, roller temperature 30 ° C Average Hertz pressure 1.2GPa, rolling speed 3.6m / s, slip ratio 3.0% The traction fluid of the present invention is shown in Table 1. As shown in, it was found that the traction performance was far superior to that of the conventional traction fluid.

Comparative Examples 1 to 7 Using a traction fluid containing 100% by weight of B component and 90% by weight of B component, a traction fluid containing OCP or PMA in the A component, and a commercially available traction fluid,
The traction coefficient was measured under the conditions shown in the examples.

As a result, as shown in Table 1, it was found that the traction coefficient was 1 to 5% smaller than that of the traction fluid of the present invention. In addition, OCP is As the olefin copolymer, specifically, a polymer of ethylene and propylene (average molecular weight: 150,000 to 300,000) is used.
MA is polymethacrylate and specifically has an average molecular weight of 5
Ten to three hundred thousand polymers were used.

(Effect of the invention) The present invention is a traction fluid in which a specific amount of a component B of branched polybutene is blended with a component A such as a diester having two cyclohexyl rings, and it has an extremely high traction coefficient and is inexpensive. Moreover, it has excellent viscosity characteristics.

Therefore, when it is used for a power transmission device, particularly a traction drive device, the shearing force under high load can be dramatically increased, so that there is an effect that the device can be downsized and an economical device can be supplied.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10M 107: 08) C10N 20:04 30:00 Z 8217-4H 40:04

Claims (4)

[Claims] 1. A general formula [In the formula, A ′ is an ester bond of —COO— or —OOC—, n is 1 to 6, R ₁ is a hydrogen atom, one or two kinds selected from an alkyl group having 1 to 8 carbon atoms, and R. ₂ is one or two selected from an alkyl group having 1 to 3 carbon atoms] to a diester compound or a derivative thereof,
1 branched polybutene with an average molecular weight of 500 to 10,000
A traction fluid characterized by containing 0 to 50% by weight. 2. The traction fluid according to claim ₁ , wherein R _{1 of the} diester compound is one or two selected from a hydrogen atom and an alkyl group having 1 to 4 carbon atoms. 3. The traction fluid according to claim 1, wherein n of the diester compound is 1 to 3. 4. The traction fluid according to claim 1, wherein R _{2 of the} diester is a methyl group.