JP2002348584A - Lubricating oil base oil composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lubricating oil base oil composition having >=150 deg.C flash point and improved low-temperature fluid flow characteristic while maintaining traction characteristics at a high temperature. SOLUTION: This lubricating oil base oil composition comprises (a) 80-98 mass % of a naphthenic synthetic lubricating oil base oil having >=140 deg.C flash point and (b) 2-20 mass % of an alcohol fatty acid ester having >=150 flash point and a geminal dimethyl structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating base oil composition, and more particularly, to an improved lubricating base oil composition, which has improved low-temperature flow characteristics while maintaining high-temperature traction characteristics and suitable for traction drive fluid compositions. The present invention relates to a lubricating base oil composition.

[0002]

2. Description of the Related Art A traction drive fluid used in a traction type CVT (continuously variable transmission) for automobiles satisfies the contradictory performances of high traction coefficient even at high temperatures and low viscosity at low temperatures. is necessary. In other words, a synthetic naphthene-based compound having a high traction coefficient at high temperatures has poor low-temperature fluidity. To solve the problem, an additive may be added, but the traction coefficient at high temperatures tends to decrease. For example, JP-A-2000-
Japanese Patent No. 204386 discloses a traction drive fluid composition in which a poly-α-olefin is added to a naphthenic synthetic lubricating base oil. However, when a large amount is added, the traction coefficient at a high temperature is higher than the additive property. There was a drawback of lowering. In general, the flash point of automotive lubricating oils is desirably practically maintained at 150 ° C. or higher.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made from the above viewpoint, and has a flash point of 150 ° C. or higher, and has improved lubricating oil characteristics at low temperatures while maintaining traction characteristics at high temperatures. It is intended to provide an oil composition.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have achieved the object of the present invention effectively by blending a small amount of a specific ester compound with a naphthenic synthetic lubricating base oil. It has been found that the present invention can be performed and the present invention has been completed. That is, the gist of the present invention is as follows. 1. (A) 80 to 98% by mass of a naphthenic synthetic lubricating base oil having a flash point of 140 ° C or higher and (b) 2 to 20% by mass of a fatty acid ester of a gem-type dimethyl structure alcohol having a flash point of 150 ° C or higher % Lubricating base oil composition. 2. 2. The lubricating base oil composition according to the above 1, wherein the lubricating base oil composition has a flash point of 150 ° C. or higher. 3. Naphthenic synthetic lubricating base oil is a cyclohexane ring,
3. The lubricating base oil composition according to the above 1 or 2, which is a compound having a ring selected from a bicycloheptane ring and a bicyclooctane ring. 4. Naphthenic synthetic lubricating base oil is a cyclohexane ring,
Bicyclo [2.2.1] heptane ring, bicyclo [3.
2.1] The compound according to any one of the above items 1 to 3, which is a compound having at least two rings selected from an octane ring, a bicyclo [2.2.2] octane ring and a bicyclo [3.3.0] octane ring. Lubricating base oil composition. 5. The lubricating base oil composition according to any one of the above items 1 to 4, wherein the alcohol is 3,3,5-trimethylhexanol, 3,5,5,7,7-pentamethyloctanol or neopentyl glycol. 6. The lubricating base oil composition according to any one of the above 1 to 5, wherein the fatty acid has a gem-type dimethyl structure. 7. The lubricating base oil composition according to any one of the above 1 to 6, wherein the fatty acid is 3,5,5-trimethylhexanoic acid. 8. 8. The lubricating base oil composition according to any one of the above items 1 to 7, wherein the fatty acid ester of an alcohol having a gem-type dimethyl structure has a total carbon number of 18 to 23. 9. 9. The lubricating base oil composition according to any one of the above 1 to 8, wherein the lubricating base oil composition is a traction drive fluid base oil composition.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. First, the component (a) constituting the present invention comprises 140
It is a naphthenic synthetic lubricating base oil having a flash point of at least ℃. When the flash point is lower than 140 ° C., the flash point is not easily increased to 150 ° C. or higher even when an ester compound is mixed, which is not preferable. As the naphthenic synthetic lubricating base oil, a compound having a ring selected from a cyclohexane ring, a bicycloheptane ring and a bicyclooctane ring is preferable. Among them, a cyclohexane ring, a bicyclo [2.2.1] heptane ring,
Bicyclo [3.2.1] octane ring, bicyclo [2.
Compounds having at least two rings selected from [2.2] octane ring and bicyclo [3.3.0] octane ring are particularly preferred.

Specifically, bicyclo [2.2.1] heptane ring compound, bicyclo [3.2.1] octane ring compound, bicyclo [3.3.0] octane ring compound, bicyclo [2.2. 2] dimer hydride of at least one alicyclic compound selected from octane ring compounds, and 2,4
-Dicyclohexyl-2-methylpentane, 2,4-dicyclohexylpentane, 2,4-dicyclohexyl-
It can be preferably selected from cyclohexane ring compounds such as 2-methylbutane and 1-decahydronaphthyl-1-cyclohexylethane.

As a preferable method for producing the dimer hydride of the alicyclic compound, for example, the following olefin which may be substituted by an alkyl group may be treated in the order of dimerization, hydrogenation and distillation. Examples of the olefin which may be substituted with an alkyl group such as a methyl group, an ethyl group or a propyl group in the above raw materials include, for example, bicyclo [2.2.1] hept-2-ene; vinyl-substituted or isopropenyl-substituted bicyclo [ 2.2.1] alkenyl-substituted bicyclo [2.2.1] hept-2-ene such as hept-2-ene; methylene-substituted, ethylidene-substituted or isopropylidene-substituted bicyclo [2.2.1] hept-2-ene Alkylidene-substituted bicyclo [2.2.1] hept-2-ene such as ene; vinyl-substituted or isopropenyl-substituted bicyclo [2.
2.1] Alkenyl-substituted bicyclo such as heptane [2.
2.1] heptane; alkylidene-substituted bicyclo [2.2.1] heptane such as methylene-substituted, ethylidene-substituted or isopropylidene-substituted bicyclo [2.2.1] heptane; bicyclo [3.2.1] octene; vinyl-substituted Or alkenyl-substituted bicyclo [3.2.1] octene such as isopropenyl-substituted bicyclo [3.2.1] octene; alkylidene-substituted bicyclo such as methylene-substituted, ethylidene-substituted or isopropylidene-substituted bicyclo [3.2.1] octene [3.2.1] octene; vinyl-substituted or isopropenyl-substituted bicyclo [3.2.1]
Alkenyl-substituted bicyclo [3.2.1] octane such as octane; alkylidene-substituted bicyclo [3.2.1] octane such as methylene-substituted, ethylidene-substituted or isopropylidene-substituted bicyclo [3.2.1] octane; bicyclo [3 3.3.0] octene; alkenyl-substituted bicyclo [3.3.0] octene such as vinyl-substituted or isopropenyl-substituted bicyclo [3.3.0] octene; methylene-substituted, ethylidene-substituted or isopropylidene-substituted bicyclo [3.3] 0.0] octene and the like; alkylidene-substituted bicyclo [3.3.0] octene; alkenyl-substituted bicyclo [3.3.0] octane such as vinyl-substituted or isopropenyl-substituted bicyclo [3.3.0] octane; methylene-substituted Ethylidene- or isopropylidene-substituted bicyclo [3 3.0] alkylidene-substituted bicyclo [3.3.0 octane] octane; bicyclo [2.
2.2] octene; alkenyl-substituted bicyclo [2.2.2] octene such as vinyl-substituted or isopropenyl-substituted bicyclo [2.2.2] octene; methylene-substituted, ethylidene-substituted or isopropylidene-substituted bicyclo [2.2. 2] alkylidene-substituted bicyclo [2.2.2] octene such as octene; alkenyl-substituted bicyclo [2.2.2] octane such as vinyl-substituted or isopropenyl-substituted bicyclo [2.2.2] octane; methylene-substituted, ethylidene Examples thereof include alkylidene-substituted bicyclo [2.2.2] octane such as substituted or isopropylidene-substituted bicyclo [2.2.2] octane.

Above all, dimer hydrides of bicyclo [2.2.1] heptane ring compounds are particularly preferred. As the corresponding starting olefin, specifically, for example, bicyclo [2.2.1] heptane -2-ene; 2-methylenebicyclo [2.2.1] heptane; 2-methylbicyclo [2.2.1] hept-2-ene; 2-methylene-3-
Methylbicyclo [2.2.1] heptane; 3-methylene-2-methylbicyclo [2.2.1] heptane; 2,3
-Dimethylbicyclo [2.2.1] hept-2-ene;
2-methylene-7-methylbicyclo [2.2.1] heptane; 3-methylene-7-methylbicyclo [2.2.
1] heptane; 2,7-dimethylbicyclo [2.2.
1] Hept-2-ene; 2-methylene-5-methylbicyclo [2.2.1] heptane; 3-methylene-5-methylbicyclo [2.2.1] heptane; 2,5-dimethylbicyclo [2 2.1] hept-2-ene; 2-methylene-6-methylbicyclo [2.2.1] heptane; 3-
Methylene-6-methylbicyclo [2.2.1] heptane; 2,6-dimethylbicyclo [2.2.1] hept-
2-ene; 2-methylene-1-methylbicyclo [2.
2.1] heptane; 3-methylene-1-methylbicyclo [2.2.1] heptane; 1,2-dimethylbicyclo [2.2.1] hept-2-ene; 2-methylene-4-
Methylbicyclo [2.2.1] heptane; 3-methylene-4-methylbicyclo [2.2.1] heptane; 2,4
-Dimethylbicyclo [2.2.1] hept-2-ene;
2-methylene-3,7-dimethylbicyclo [2.2.
1] heptane; 3-methylene-2,7-dimethylbicyclo [2.2.1] heptane; 2,3,7-trimethylbicyclo [2.2.1] hept-2-ene; 2-methylene-3, 6-dimethylbicyclo [2.2.1] heptane;
3-methylene-2,6-dimethylbicyclo [2.2.
1] heptane; 2-methylene-3,3-dimethylbicyclo [2.2.1] heptane; 3-methylene-2,2-dimethylbicyclo [2.2.1] heptane; 2,3,6-
Trimethylbicyclo [2.2.1] hept-2-ene;
2-methylene-3-ethylbicyclo [2.2.1] heptane; 3-methylene-2-ethylbicyclo [2.2.
1] heptane; 2-methyl-3-ethylbicyclo [2.
2.1] Hept-2-ene and the like.

The above-mentioned dimerization means not only the dimerization of the same kind of olefin but also the co-dimerization of a plurality of different kinds of olefins. The above-mentioned olefin dimerization is usually carried out in the presence of a catalyst, if necessary, by adding a solvent. As a catalyst used for this dimerization, an acidic catalyst is usually used. Specifically, solid acids such as activated clay, zeolite, montmorillonite and ion exchange resin, mineral acids such as hydrofluoric acid and polyphosphoric acid, organic acids such as triflic acid, aluminum chloride, ferric chloride, and ferric chloride Lewis acids such as tin, boron trifluoride, boron trifluoride complex, boron tribromide, aluminum bromide, gallium chloride and gallium bromide, and organic aluminum compounds such as triethylaluminum, diethylaluminum chloride and ethylaluminum dichloride Can be mentioned.

The use amount of these catalysts is not particularly limited, but is usually in the range of 0.1 to 100% by mass based on the starting olefin. In dimerization, a solvent is not necessarily required, but it can be used for handling the raw material olefin or catalyst during the reaction or for controlling the progress of the reaction. Examples of such a solvent include saturated hydrocarbons such as various pentanes, various hexanes, various octanes, various nonanes, and various decane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclosan, and decalin;
Examples thereof include ether compounds such as diethyl ether and tetrahydrofuran, halogen-containing compounds such as methylene chloride and dichloroethane, and nitro compounds such as nitromethane and nitrobenzene.

The dimerization reaction is carried out in the presence of these catalysts and the like, and the reaction temperature is generally in the range of -70 to 200 ° C. Appropriate conditions are set within the temperature range depending on the type of catalyst, additives, and the like. The reaction pressure is usually normal pressure, and the reaction time is usually 0.5 to 10 hours. Next, the dimer of the raw material olefin thus obtained is hydrogenated to obtain a desired dimer hydride.
In addition, hydrogenation may be performed on a mixture obtained by appropriately mixing dimers dimerized separately using different raw material olefins.

This hydrogenation reaction is also usually carried out in the presence of a catalyst. Examples of the catalyst include hydrogenation catalysts such as nickel, ruthenium, palladium, platinum, rhodium and iridium. The amount of this catalyst is usually in the range of 0.1 to 100% by mass based on the dimerization product. Further, this hydrogenation reaction proceeds in the absence of a solvent as in the case of the dimerization reaction, but a solvent can be used. In this case, various solvents such as various pentanes, various hexanes, various octanes, various nonanes, Examples include saturated hydrocarbons such as various decane and alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclosan, and decalin.

The reaction temperature is usually 20 to 300 ° C.
Regarding the reaction pressure, the reaction can be carried out within a range from normal pressure to 20 MPa · G. The reaction time is usually 1 to 10 hours. The generated hydride may be mixed with a hydride generated from another raw material olefin in another step and supplied to the base oil as the component (a). Next, the component (b) constituting the present invention has a flash point of 150 ° C. or higher.
It is a fatty acid ester of an alcohol having a dimethyl structure. If the flash point is lower than 150 ° C., the flash point of the mixed oil tends to be lower than 150 ° C., which is not preferable. The alcohol constituting the ester of the component (b) has a gem-type dimethyl structure, and is preferably a monoalcohol such as 3,3,5-trimethylhexanol or 3,5,5,7,7-pentamethyloctanol. Examples thereof include diols such as neopentyl glycol and hexylene glycol. Among them, 3,3,5-trimethylhexanol, 3,5,5,7,7-pentamethyloctanol,
Neopentyl glycol is preferred.

The fatty acid constituting the ester of component (b) preferably has a gem-type dimethyl structure. Specifically, 3,5,5-trimethylhexanoic acid, 3,5,5,5
7,7-pentamethyloctanoic acid and the like can be mentioned, and among them, 3,5,5-trimethylhexanoic acid is particularly preferable. When the alcohol is a diol, the ester of the component (b) may be a monoester or a diester. Further, the total carbon number of the ester of the component (b) is 18 to
It is more preferable to adjust to 23.

The above lubricating base oil composition can be obtained by blending the components (a) and (b).
The ratio of the component and the component (b) is, based on the sum of the component (a) and the component (b), 80 to 98% by mass of the component (a) and 2 to 20% by mass of the component (b). .
Explaining in terms of the proportion of the component (b), if it is less than 2% by mass, the effect of improving low-temperature fluidity is small, and if it exceeds 20% by mass, the high-temperature traction coefficient of the composition decreases. Preferably it is in the range of 3 to 18% by mass. Therefore, a preferable range of the component (a) is 82 to 97% by mass.

The lubricating base oil composition of the present invention may optionally contain an antioxidant, a rust inhibitor, a detergent / dispersant, a pour point depressant, a viscosity index improver, an extreme pressure agent, an antiwear agent, an oil agent, Various additives such as an antifoaming agent and a corrosion inhibitor can be blended in appropriate amounts. The lubricating base oil composition of the present invention can be used for a traction drive fluid, a transmission oil, a hydraulic oil, a compressor oil, an electric insulating oil, and the like, but is particularly preferably used for a traction drive fluid.

[0017]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. [Reference Example 1] 350.5 g (5 mol) of crotonaldehyde and 198.3 g (1.5 mol) of dicyclopentadiene were charged into a 1-liter stainless steel autoclave and reacted by stirring at 170 ° C for 2 hours. After cooling the reaction solution to room temperature, 22 g of a 5% by mass ruthenium-carbon catalyst (manufactured by NE Chemcat) was added, and a hydrogen pressure of 6.
Hydrogenation was performed at 86 MPa · G and a reaction temperature of 180 ° C. for 4 hours. After cooling, the catalyst was filtered off, and the filtrate was distilled under reduced pressure.
242 g of a 70 ° C./1.20 hPa fraction was obtained. This fraction was analyzed by mass spectrum and nuclear magnetic resonance spectrum. As a result, this fraction was found to be 2-hydroxymethyl-3-methylbicyclo [2.2.1] heptane and 3-hydroxymethyl-
It was confirmed to be 2-methylbicyclo [2.2.1] heptane.

Next, 15 g of γ-alumina (N612, manufactured by Nikki Chemical Co., Ltd.) was placed in a flow-type atmospheric pressure reaction tube made of quartz glass having an outer diameter of 20 mm and a length of 500 mm.
The dehydration reaction was performed at 1.0 ° C. and a weight hourly space velocity (WHSV) of 1.07 hr ⁻¹ , and 2-methylene-3-methylbicyclo [2.
2.1] Heptane and 65% by mass of 3-methylene-2-methylbicyclo [2.2.1] heptane and 28% by mass of 2,3-dimethylbicyclo [2.2.1] hept-2-ene
2-hydroxymethyl-3-methylbicyclo [2.2.1] heptane and 3-hydroxymethyl-2-
196 g of a dehydration reaction product of methylbicyclo [2.2.1] heptane was obtained.

(Preparation of dimer hydride) 9.5 g of dried activated clay [Galeon Earth NS manufactured by Mizusawa Chemical Industry Co., Ltd.] and 190 g of the olefin compound obtained above were placed in a 500 ml four-necked flask and placed at 145 ° C. For 3 hours to carry out a dimerization reaction. After filtering activated clay from this reaction mixture, nickel / diatomaceous earth catalyst for hydrogenation (N-113, manufactured by JGC Chemicals) was placed in a 1-liter autoclave.
6 g, hydrogen pressure 3.92 MPa · G, reaction temperature 16
The hydrogenation reaction was performed under the conditions of 0 ° C. and a reaction time of 3 hours. After completion of the reaction, the catalyst was removed by filtration, and the filtrate was distilled under reduced pressure to give a boiling point of 126 to 128 ° C / 2.67 daP.
116 g of dimer hydride of fraction a were obtained. Table 1 shows the general properties of the dimer hydride and the measurement results of the traction coefficient.

Comparative Example 1 The base oil obtained in Reference Example 1
1-decene dimer hydride (Idemitsu PAO-500
2, a flash point of 171 ° C.) was incorporated in an amount of 15% by mass based on the total amount of the composition. Table 1 shows the general properties of the composition and the measurement results of the traction coefficient.

Example 1 The base oil obtained in Reference Example 1 was
An ester compound (3,3,5-trimethylhexanoic acid 3,5,5-trimethylhexanol ester, manufactured by Higher Alcohol Industry Co., Ltd., with a flash point of 156 ° C.) was blended in an amount of 15% by mass based on the total amount of the composition. Table 1 shows the general properties of the composition and the measurement results of the traction coefficient.

Reference Example 2 A 500 ml four-necked flask equipped with a reflux condenser, a stirrer, and a thermometer was
Activated clay [Galeon Earth NS, manufactured by Mizusawa Chemical Industry Co., Ltd.] 4
g, 10 g of diethylene glycol monoethyl ether and 200 g of α-methylstyrene, and the reaction temperature was 105 ° C.
And stirred for 4 hours. After completion of the reaction, the product liquid was analyzed by gas chromatography, and the conversion was 70%, the selectivity of the target α-methylstyrene linear dimer was 95%, and the by-product α-methylstyrene cyclic dimer was selected. It was found that the selectivity was 1% and the selectivity for high-boiling substances such as trimers was 4%. This reaction product was hydrogenated and distilled under reduced pressure in the same manner as in Comparative Example 1 to obtain a 99% by mass pure α-methylstyrene linear dimer hydride, that is, 2,4-dicyclohexyl-2.
-125 g of methylpentane were obtained. Table 1 shows the general properties of the dimer hydride and the measurement results of the traction coefficient.

Example 2 Base oil (2,4-dicyclohexyl-2-methylpentane) obtained in Reference Example 2
Then, an ester compound (3,3,5-trimethylhexanoic acid 3,5,5-trimethylhexanol ester, manufactured by Higher Alcohol Industry Co., Ltd., flash point 156 ° C.) was blended at 10% by mass based on the total amount of the composition. Table 1 shows the general properties of the composition and the measurement results of the traction coefficient.

Example 3 Base oil obtained in Reference Example 2 (2,4-dicyclohexyl-2-methylpentane)
Then, an ester compound (3,3,5-trimethylhexanoic acid 3,5,5-trimethylhexanol ester, manufactured by Higher Alcohol Industry Co., Ltd., flash point 156 ° C.) was blended in an amount of 15% by mass based on the total amount of the composition. Table 1 shows the general properties of the composition and the measurement results of the traction coefficient.

The measurement of the traction coefficient in the above Examples and Comparative Examples was performed using a two-cylinder friction tester. That is, a cylinder of the same size in contact (diameter 52
mm, thickness 6mm, the driven side is a Tyco type with a radius of curvature of 10mm, and the driving side is a flat type without crowning). Apply a load of 98.0N with the weight,
The tangential force generated between the two cylinders, that is, the traction force was measured, and the traction coefficient was determined. This cylinder is bearing steel SU
J-2 Mirror finish, average peripheral speed 6.8m /
s, the maximum Hertz contact pressure was 1.23 GPa. In measuring the traction coefficient at a fluid temperature (oil temperature) of 140 ° C., the oil temperature was raised from 40 ° C. to 140 ° C. by heating the oil tank with a heater.
The traction coefficient at a slip ratio of 5% was determined.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

The lubricating base oil composition of the present invention has a temperature of 150 ° C.
While maintaining the above flash point, it has a high traction coefficient at high temperatures and excellent low-temperature fluidity, and can be practically used as a traction drive type CVT oil worldwide from cold regions to high temperature regions. .

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10N 30:02 C10N 30:02 30:08 30:08 30:20 30:20 40:04 40:04 40 : 08 40:08 40:16 40:16 40:30 40:30 (72) Inventor Kazushi Hata 24-4 Anesaki Beach, Ichihara-shi, Chiba Prefecture (72) Inventor Toshiyuki Tsubuchi 1280 Kamiizumi, Sodegaura-shi, Chiba Prefecture F-term (Reference) 4H104 BA02A BB32A BB34A EA04A LA01 LA04 LA20 PA03 PA05 PA12 PA20

Claims (9)

[Claims] (1) 80-98% by mass of a naphthenic synthetic lubricating base oil having a flash point of 140 ° C. or more and (b) 1
A lubricating base oil composition comprising 2 to 20% by mass of a fatty acid ester of an alcohol having a gem-type dimethyl structure and having a flash point of 50 ° C or higher. 2. The lubricating base oil composition according to claim 1, wherein the lubricating base oil composition has a flash point of 150 ° C. or higher. 3. The lubricating base oil composition according to claim 1, wherein the naphthenic synthetic lubricating base oil is a compound having a ring selected from a cyclohexane ring, a bicycloheptane ring and a bicyclooctane ring. 4. A naphthenic synthetic lubricating base oil comprising a cyclohexane ring, a bicyclo [2.2.1] heptane ring, a bicyclo [3.2.1] octane ring, and a bicyclo [2.2.2].
The lubricating base oil composition according to any one of claims 1 to 3, which is a compound having at least two rings selected from an octane ring and a bicyclo [3.3.0] octane ring. 5. The method according to claim 1, wherein the alcohol is 3,3,5-trimethylhexanol, 3,5,5,7,7-pentamethyloctanol or neopentyl glycol.
5. The lubricating base oil composition according to any one of 4. 6. The lubricating base oil composition according to claim 1, wherein the fatty acid has a gem-type dimethyl structure. 7. The lubricating base oil composition according to claim 1, wherein the fatty acid is 3,5,5-trimethylhexanoic acid. 8. The lubricating base oil composition according to claim 1, wherein the fatty acid ester of an alcohol having a gem-type dimethyl structure has a total carbon number of 18 to 23. 9. The lubricating base oil composition according to claim 1, wherein the lubricating base oil composition is a traction drive fluid base oil composition.