JPS62290796A - Synthetic lubricating fluid - Google Patents

Abstract

PURPOSE:To obtain a synthetic lubricating fluid which has a high coefficient of traction and is relatively inexpensive, by incorporating a particular cyclohexanol/cyclohexanecarboxylic acid ester compd. (derivative). CONSTITUTION:1mol of a monohydric alcohol compd. (e.g., cyclohexanol) is esterified with a cyclohexanecarboxylic acid compd. (e.g., cyclohexylacetic acid) in an amt. of 1.2-2 times by mol the amt. of the monohydric alcohol compd. at 150-250 deg.C for 10-40hr to obtain a cyclohexanol/ cyclohexanecarboxylic acid ester compd. or its derivative (A) of the formula (wherein m and n are each 0-5, provided that m+n=1-10; R1 is H or a 1-8C alkyl; and R2 is H or 1-3C alkyl). 1-70wt% branched poly-alpha-olefin having an MW of 500-10,000 (e.g., polybutene) is incorporated in component A.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a synthetic lubricating fluid comprising a cyclohexanol cyclohexane carboxylic acid monoester compound and a branched polyalphaolefin blended with the ester.

(Prior Art) In automobiles or industrial machines, traction drive power transmission devices that transmit power to driven parts using traction drive mechanisms have attracted attention, and research and development have been actively promoted in recent years. A traction drive mechanism is a power transmission mechanism that uses rolling friction, etc., and because it does not use gears like conventional gears, vibration and noise are reduced, and gear changes at high speeds can be performed very smoothly. In the automobile industry, improving the fuel efficiency of automobiles has become an important issue, but by applying traction drive to the automobile transmission and making it continuously variable, the engine can always be operated in its maximum fuel efficiency range, making it possible to improve the fuel efficiency of conventional transmissions. It is said that fuel consumption can be reduced by more than 2,096 points compared to conventional systems. Recent research results include the development of materials with high fatigue strength and theoretical analysis of the Traxidin mechanism, and the correlation between the traction coefficients of Traxidin fluid at the molecular structure level of its components is gradually being elucidated. be. Here, the traction coefficient is defined as the ratio of the traction force generated by sliding of the contact portions of rotating bodies that contact each other in a rolling friction power transmission device to the normal load.

Traction fluid must be a lubricating oil with a high traxidin coefficient, and it has been confirmed that those with a naphthene ring in their molecular structure exhibit high performance. 7.■You6
Hiro, Chi,, 11-c. As a traction fluid having a caften ring, Japanese Patent Publication No. 47-35763 discloses di(cyclohexyl)alkane or dicyclohexane. This patent states that a fluid containing a perhydrogenated (alpha methyl) styrene polymer, a hydrindane compound, etc. in the alkane compound has a high tracundin coefficient. Further, JP-A No. 59-191797 discloses a traxidine fluid containing an ester compound having a naphthene ring, in which cyclohequinyldicarboxylic acid dicyclohexyl ester or phthalic acid dicyclohexyl ester is used in traxidine fluid. It is preferred as such.

(Problems to be solved by the invention) In recent years, the automobile industry has been actively promoting the development of continuously variable transmissions. Fluids with as high a traction coefficient as possible are highly desired because the allowable transmission force can be increased with the same device, making it possible to downsize the entire device and reducing the amount of exhaust gases that are a problem in terms of pollution. However, even if there are currently commercially available traction fluids that are said to have high performance, they do not provide satisfactory performance in terms of traction coefficient when used in such traction drive devices, and are expensive. There's a problem. In addition, the traction fluid proposed in Japanese Patent Publication No. 4B-35763 is also
-Uh, 2. ■Ah, 1+. Similar substances.

- There are also problems in terms of performance and price since it is used as a component.

(Means for Solving the Problems) As a result of extensive research in order to obtain a traction fluid that has a high traction coefficient and is relatively inexpensive, the present inventors have discovered an ester or its The present invention was completed by confirming that it is possible to economically provide a base oil fluid with high performance by blending a branched polyalphaolefin with the derivative and the Nistyl.

The present invention first relates to a cyclohexanol cyclohexane carboxylic acid ester compound or a derivative thereof, that is, a compound of the general formula [where n is 0 to 5, m is θ to 5, and n0m is 1 to 1
0, R1 is the same or different hydrogen atom or a C1-8 alkyl group, and R2 is a hydrogen atom or a C1-3 alkyl group]. This is a related invention. Furthermore, a second invention is a synthetic lubricating fluid comprising 1 to 70% by weight of branched polyalphaolefin added to the cyclohexanol cyclohexane carboxylic acid ester or its derivative.

A first object of the present invention is to provide a synthetic lubricating fluid with superior properties having a high traction coefficient. A second object of the present invention is to provide a synthetic lubricating fluid that is economical and easy to apply to equipment.

The fluid of the present invention includes an ester having two cyclohexyl rings at both ends or a derivative thereof (hereinafter sometimes referred to as component A), and a polyalphaolefin having branches in the ester (hereinafter referred to as component B). ) is blended in a specific amount.

Component A is an ester represented by the above structural formula, where n is θ~5, m is θ~5, and n0m is 1~5.
IO, preferably an ester in which n is 1 to 3 and m is 1 to 3. When n+m is 0, the traxidin coefficient is small, and when n+m is 11 or more, the viscosity is high, which is not preferable. Further, R1 is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms,
Preferably it is a hydrogen atom or a methyl group. Furthermore, R7 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom. R1 is an alkyl group having 9 or more carbon atoms,
Alternatively, when R2 is an alkyl group having 4 or more carbon atoms, it is not preferable because it is easy to decompose and the viscosity is too low.

This ester or its derivative is produced by the following method and has a viscosity of 5 to 50 cst at 40°C, particularly preferably 10 to 30 cst, and 1 to 1 ocst at 100°C.
.

Particularly preferred is one that develops a viscosity of 2 to 5 cst. Furthermore, examples of ester derivatives include amino compounds and ether compounds.

Ester can be produced by the method shown below. That is, it is a method based on an esterification reaction between a -hydric alcohol compound and a cyclohexanecarboxylic acid compound. The -hydric alcohol compound has a cyclohexyl ring and the structural formula is 18!, in which R1 is selected from hydrogen or an alkyl group having 1 to 4 carbon atoms. Alternatively, R2 is a compound in which two or more types are selected from a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and m is 0 to 5.

In particularly preferred monohydric alcohols, R is hydrogen or a methyl group, R2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
It is a compound where m is 0-2. Specific examples include cyclohexanol, methylcyclohexanol, and cyclohexylcarbinol. The cyclohexanecarboxylic acid compound has a structural formula R2, R1 is one or more selected from a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R2 is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. It is a compound selected from the alkyl group of A particularly preferred carboxylic acid compound is a compound in which R1 is hydrogen or a methyl group, R2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is θ to 2. Specific examples include cyclohexanecarboxylic acid, cyclohexyl acetic acid, and cyclohexylbropionic acid. The esterification reaction is carried out using a catalyst such as phosphoric acid in an excess of alcohol or under an excess of acid, but it is preferable to employ an excess of acid.

That is, it resists 1 mol of alcohol compound and 1.2 mol of acid.
to 2 times the mole (particularly preferably 1.5 to 1.8 times the mole). The reaction temperature is 150-250°C, preferably 170-230°C, and the reaction time is 10-40 hours, preferably 15-25 hours. The reaction pressure may be increased or reduced pressure, but normal pressure is preferred from the viewpoint of reaction operation. Under this condition, excess acid acts as a catalyst.

Further, an appropriate amount of alkylbenzene such as xylene or toluene can be added as a solvent. By adding a solvent, the reaction and temperature can be easily controlled. As the reaction progresses, the produced water evaporates, but the reaction is terminated when the amount of water becomes equal to the mole of alcohol. Excess acid is neutralized with an aqueous alkaline solution and removed by washing with water.

When using an acid that is difficult to remove with alkaline washing,
The acid is 2 to 2.5 times the molar amount of the alcohol and the reaction is carried out using a catalyst. As the catalyst, phosphoric acid, para-toluenesulfonic acid, sulfuric acid, etc. can be used, but it is most preferable to use phosphoric acid in terms of increasing the reaction rate and increasing the yield of ester. The ester compound of the present invention is obtained by finally distilling the reaction product under reduced pressure to remove water and solvent. When carrying out the reaction under alcohol excess conditions, the alcohol compound is reacted in a molar amount of 1.5 to 3 times the amount of the carboxylic acid. The reaction temperature is 150 to 250°C, preferably 170 to 230°C, and the reaction time is 10 to 40 hours.
Preferably it is 15 to 25 hours. The reaction pressure may be increased or reduced pressure, but normal pressure is preferred from the viewpoint of reaction operation. Further, an appropriate amount of alkylbenzene such as xylene or toluene can be added as a solvent. By adding a solvent, the reaction temperature can be easily controlled. As the reaction progresses, the produced water evaporates, but the reaction is terminated when this water reaches equal moles of the carboxylic acid. Phosphoric acid, p-toluenesulfonic acid, sulfuric acid, etc. are used as a catalyst. Phosphoric acid is most preferably used since it increases the reaction rate and yield of ester. The ester compound of the present invention is obtained by finally distilling the reaction product under reduced pressure to remove water, solvent, and excess alcohol.

Although the ester of the present invention exhibits a high traction coefficient even when used alone, a more preferable traction fluid can be obtained by blending polyalphaolefin such as polybutene or other ester as a second component.

The polyalphaolefin as the second component has a quaternary carbon atom or a tertiary carbon atom in its main chain, and is a polymer of a alphaolefin having 3 to 5 carbon atoms and a hydrogenated product thereof. Examples include polypropylene, polybutene, polyisobutylene, polybentene, and hydrogenated products thereof, and particularly preferred are polybutene, polyisobutylene, and hydrogenated products thereof. Polyisobutylene can be represented by the following structural formula.

CH3CH3 Moreover, the hydrogenated product is shown by the following structural formula.

However, the above degree of polymerization n is 5 to 200.

Polybutene and polyisobutylene may be commercially available products, but they can also be produced by known polymerization methods.In addition, their hydrogenated products are produced by reacting polyisobutylene etc. in the presence of hydrogen.Particularly preferred polybutenes and polyisobutylene The alpha olefin has a molecular ffi in the range of 300 to 10.000, more preferably 500 to 5.000;
Use what is within range. The molecular weight may be adjusted by decomposing a high molecular weight polyalphaolefin, mixing polyalphaolefins with different molecular weights, etc. Incidentally, although there is an alpha olefin copolymer (OCP) as a type of polyalpha olefin, this oCP is not suitable for use as the second component of the present invention.

The reason for this is that OCP is obtained by polymerizing two or more alpha olefins and has a structure in which they are irregularly connected, and is not a regular gem-dialkyl type structure like polybutene or the like.

As the second component of the present invention, an ester having two or more cyclohexyl rings and 1 to 3111 ester bonds (hereinafter referred to as ester B) is selected. As ester B, monoester obtained by esterification of a cyclohexanol compound and a carboxylic acid compound,
Diesters or triesters may be mentioned. Particularly preferred esters B are monoesters or diesters having 1 to 10 carbon atoms in the center and one cyclohexyl ring at each end.

The detailed structure and manufacturing method of these esters B are disclosed in the patent application filed by the present inventors (Japanese Patent Application No. 60-27832,
-294424, 61-19226).

The ester in the present invention, for example, the monoester of cyclohexyl acetic acid and cyclohexylcarbinol, exhibits a traction coefficient of 0.104 to o.ioa, and the second component, for example polybutene, has a traction coefficient of 0.07.
5 to 0.01i5, and ester B (monoester of cyclohexanecarboxylic acid and cyclohexanol) is
It shows a value of 0.090 to 0.092.

Since the ester (first component) of the present invention has a high traction coefficient, even if the first component is applied alone to a traction drive device, high performance can be achieved. However, 0.1 to 95% by weight of the second component, polyalphaolefin or ester B, is added to this first component, especially 10 to 7% by weight.
By blending 0% by weight, a more preferable traction fluid can be obtained. That is, although the traction coefficient of the second component is lower than or almost the same as that of component A, the gem-dialkyl group or cyclohexyl ring of the second component has a synergistic effect with the cyclohexyl ring of the first component (
traction coefficient improvement effect).

Moreover, the second component is relatively cheap and has excellent viscosity characteristics, so by adding 0.1 to 95 ffi-% to the first component, it is possible to economically obtain traction fluid without lowering the traction coefficient. It is possible.

The synthetic lubricating fluid of the present invention may also contain various additives depending on the intended use. In other words, if the traction device is subject to high temperatures and heavy loads, antioxidants,
Approximately 0.05 to 5% by weight of one or more types of additives such as anti-wear agents or anti-corrosion agents can be blended.

Similarly, when a high viscosity index is required, 1 to 10% by weight of a known viscosity index improver may be blended. However, if polymethacrylate or olefin copolymer is used, the traction coefficient will be lowered, so it is desirable that the amount of these added be 4xffl 96 or less.

In the present invention, the synthetic lubricating fluid or traction fluid refers to a fluid used in a device that transmits rotational torque through point contact or line contact, or a transmission device that has a similar structure. The synthetic lubricating fluid of the present invention has a higher traction coefficient than conventionally known fluids, and has a traction coefficient 5 to 1596 higher than conventional products, depending on properties such as viscosity. Therefore, the synthetic lubricating fluid of the present invention can be used not only in internal combustion engines such as small passenger cars, but also in relatively low-power transmission devices such as spinning machines and food manufacturing machines.
It can also be preferably applied to traction live equipment such as large-power industrial machines.

(Function) The synthetic lubricating fluid of the present invention has a much superior traction coefficient compared to known fluids, but
The reason for the high traction coefficient has not yet been completely elucidated. It is believed that this is basically based on the unique molecular structure of the synthetic lubricating fluid of the present invention.

First, the synthetic lubricating fluid (first component) of the present invention is an ester having two cyclohexyl rings in the compound molecule,
Due to the ester bond, a dipole force acts between the molecules. It is believed that this dipole opening force changes the fluid into a stable glass state and increases the anti-shear force under the high load conditions of the Traxidine device. Furthermore, if the second component is blended with the ester of the present invention, since the second component has a gem-dialkyl type quaternary carbon or a cyclohexyl ring, the cyclohexyl ring of the first component will be combined with the cyclohexyl ring when the Traxidine device is under high load. It is thought that the gem-dialkyl moiety or cyclohexyl ring of the quaternary carbon of the second component is tightly interlocked with each other like a gear, and when the load is released, it quickly separates and becomes fluidized.

(Example) Examples 1 to 19 Ester Al of the present invention was synthesized by the following method. First, cyclohexyl acetic acid, cyclohexyl carbinol (molar ratio 3:1), and 6 g of phosphoric acid were collected in a reaction vessel. Next, the reaction vessel was heated to 200°C and the reaction was carried out under normal pressure. Heating was terminated when the amount of water produced as the reaction progressed reached twice the mole of cyclohexyl acetic acid. In order to remove unreacted substances from the mixture of the reaction product, ester of cyclohexyl acetic acid and cyclohexyl carbinol, and the unreacted substance, cyclohexyl acetic acid, vacuum distillation was performed after alkali washing, and pure ester A1 was isolated.

Ester A2 of the present invention using the above raw materials in the same manner. A3
was synthesized.

A2...Cyclohexylacetic acid and cyclohexylcarbinol (n-1, m-0 in the above structural formula) A3...Cyclohexylacetic acid and cyclohexanol (
In the above structural formula, n-0, m-1) Next, the esters AI, A2 and A3 produced in this way alone or these esters are combined with hydrogenated polybutene (Bl) having an average molecular weight of 1350, and polybutene (B2) having an average molecular weight of 900. ), polybutene (B3) with average molecule m 2350 or polybutene (B4) with average molecule i 420
) was blended and the traction coefficient was measured.

The conditions for measuring the traction coefficient are as follows.

Measuring device: Soda type 40-ra traction tester Test conditions: Oil temperature 20°C, roller temperature 30°C, average Hertzian pressure 1.2 GPa.

Rolling speed 3.6m/s.

Slip rate: 3.0% As shown in Table 1, the synthetic lubricating fluid of the present invention was found to have significantly superior traxicin performance compared to conventional traxidin fluid.

Comparative Examples 1 to 6 Traction coefficients were determined by MI under the conditions shown in Examples using a traction fluid containing only polybutene (+00 = 96) and a commercially available Traxidin fluid.

As a result, as shown in Table 1, the traccidin coefficient is 5 to b compared to any of the synthetic lubricating fluids of the present invention.Table 1 (Effects of the Invention) It is a synthetic lubricating fluid that uses a specific amount of alpha olefin as a base oil, and it not only has an extremely high traction coefficient, but is also inexpensive and has excellent viscosity characteristics.

Therefore, when used in a power transmission device, particularly a traction drive device, the shearing force under high loads can be dramatically increased, so that the device can be miniaturized and economically supplied.

Claims (1)

[Claims] 1) General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, n is 0 to 5, m is 0 to 5, but n+m is 1 to 1
0, and R_1 is the same or different hydrogen atom or
The alkyl group having 1 to 8 carbon atoms and R_2 are the same or different and represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. A synthetic lubricating fluid characterized by containing a cyclohexanol cyclohexane carboxylic acid ester compound or a derivative thereof. 2) The fluid according to claim 1, wherein n of the ester is 1 to 3. 3) The fluid according to claim 1, wherein m of the ester is 1 to 3. 4) The fluid according to claim 1, wherein R_1 of the ester is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 5) The fluid according to claim 1, wherein R_2 of the ester is a hydrogen atom or a methyl group. 6) The fluid according to claim 1, wherein the synthetic lubricating fluid is a traction fluid. 7) General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, n is 0 to 5, m is 0 to 5, but n+m is 1 to 1
0, R_1 is the same or different and represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R_2 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ] A synthetic lubricating fluid characterized in that 1 to 70% by weight of a branched polyalphaolefin is blended with the cyclohexanol cyclohexane carboxylic acid ester compound or its derivative. 8) The polyalphaolefin has an average molecular weight of 500 to
10,000. 9) The polyalphaolefin has an average molecular weight of 900 to
9. A fluid according to claim 7 or claim 8, which is a polybutene of 5000. 10) The fluid according to claim 7, 8 or 9, which contains 10 to 50% by weight of polyalphaolefin. 11) Claim 6 in which n of the ester is 1 to 3
Fluids listed in section. 12) Claim 5 in which m of the ester is 1 to 3
Fluids listed in section. 13) The fluid according to claim 6, wherein R_1 of the ester is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 14) The fluid according to claim 6, wherein R_2 of the ester is a hydrogen atom or a methyl group. 15) The fluid according to any one of claims 7 to 14, wherein the synthetic lubricating fluid is a traction fluid.