JPH0531915B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a traction drive fluid,
More specifically, the present invention relates to a traction drive fluid that is blended with two specific types of compounds as main components and has improved traction performance at high temperatures. [Prior art and problems to be solved by the invention] In general, traction drive fluid is used in traction drive devices (friction drive devices using rolling contact), such as continuously variable transmissions for automobiles and continuously variable transmissions for industrial use. It is a fluid used in hydraulic equipment, etc., and is required to have a high traction coefficient, stability against heat and oxidation, and economic efficiency. In recent years, research has been conducted to reduce the size and weight of traction drive devices, mainly for use in automobiles and the like. Along with this, the traction drive fluid used in this traction drive device has the ability to withstand use under various harsh conditions, especially over a wide temperature range from low to high temperatures (approximately -30 to 140 degrees Celsius). Therefore, it is required to be able to stably exhibit high performance (high traction coefficient, low viscosity, excellent oxidation stability, etc.). Various compounds have been proposed as traction drive fluids, but none of the traction drive fluids that have been developed so far can satisfy all of the above-mentioned required properties. The problem with the compound was that it had a low traction coefficient at high temperatures. [Means for Solving the Problems] Therefore, the present inventors have solved the problems of the above-mentioned conventional technology, and developed a method that can be used at high temperatures without impairing the traction performance of the base oil at low temperatures and without significantly increasing the kinematic viscosity. We conducted extensive research to develop a traction drive fluid with an improved traction coefficient. As a result, it was discovered that a mixture of a specific group of compounds in a specific group of base oils has excellent overall performance as a traction drive fluid, and the traction coefficient increases synergistically, especially at high temperatures. I was able to complete it. That is, in the present invention, (A) the kinematic viscosity at 100°C is
(i) at least two cyclohexyl alkyl groups, (ii) at least two cyclohexyl groups, or (iii) at least one cyclohexyl alkyl group and at least one cyclohexyl group bonded to a base oil of 8 cSt or less and (B) a decalin ring. The main component is decalin derivative, and the kinematic viscosity at 100℃ is
The present invention provides a traction drive fluid characterized by having a strength of 3 cSt or more. The traction drive fluid of the present invention has both the above-mentioned components (A) and (B) as main components. Component (A) may be any base oil with a kinematic viscosity at 100°C of 8 cSt or less, preferably 7 cSt or less, including naphthenic base oils, aromatic base oils, paraffinic base oils, silicone base oils, and esters. Suitable are base oils based on these base oils, and mixtures of these base oils, with naphthenic base oils being particularly preferred. Here, various naphthenic base oils can be mentioned. Specifically, 1-(2-decalyl)-1-cyclohexylethane, 1-(1-decalyl)-1-cyclohexylethane, 1-(2-methyldecalyl)-1-cyclohexylethane, 1-(1-methyldecalyl) )-1
-Cyclohexylethane, 1-dimethyldecaryl-1-cyclohexylethane, 2-(2-decalyl)-2-cyclohexylpropane, 2-(1-decaryl)-2-cyclohexylpropane, 1-cyclohexyl-1,4-dimethyl Decalin, 1,
2-di(methylcyclohexyl)-2-methylpropane, 2,3-di(methylcyclohexyl)-
Butane, 1,3-dicyclohexyl-3-methylbutane, 2,4-dicyclohexylpentane,
2,4-dicyclohexyl-2-methylpentane, 1,3-dicyclohexyl-1-methylcyclopentane, tercyclohexyl, cyclohexylmethyldecalin, 1-dicyclohexyl-1-
Examples include cyclohexylethane and naphthenic mineral oil. Examples of aromatic base oils include hard alkylbenzenes obtained by reacting propylene polymers with benzene, soft alkylbenzenes obtained by reacting α-olefin with benzene, and alkyl benzenes such as diisopropylnaphthalene. These include naphthalene, alkylbiphenyl such as diethylbiphenyl, diarylalkane such as phenylxylylethane, benzylnaphthalene, etc.
Examples of the paraffin base oil include polyα-olefin, paraffin mineral oil, polybutene, propylene oligomer, and squalane. Silicone base oils include silicone oils such as dimethyl silicone and phenylmethyl silicone, and ester base oils include polyol esters, diesters, cyclohexane carboxylic acid esters of cyclohexanol, and cyclohexane carboxylic acid esters of cyclododecal. cycloalkylcarboxylic acid esters of cycloalkanols such as cycloalkanols, and phosphoric acid esters such as tricyclohexyl phosphate. Each of these base oils may be used alone as component (A), or a mixture of two or more may be used as component (A). When a mixture of two or more types is used as component (A), even if one of them has a kinematic viscosity at 100°C of more than 8 cSt, it is sufficient that the mixture has a kinematic viscosity of 8 cSt or less. On the other hand, component (B) used together with component (A) above includes (i) two or more cyclohexylalkyl groups, (ii) two or more cyclohexyl groups, or (iii) a cyclohexylalkyl group and a cyclohexyl group on the decalin ring. It is a decalin derivative formed by bonding one or more of each. Various things can be used as this (B) component, but among them, the following general formula [] [In the formula, R ¹ to ^{R 8} each represent hydrogen or an alkyl group having 1 to 4 carbon atoms, and p, q, r, and s each represent an integer of 1 to 3. Moreover, m and n are each integers of 0 to 3, and the sum of both is 2 or 3. ] Decalin derivatives represented by, that is, those in which two or more cyclohexyl alkyl groups are bonded to the decalin ring, and the cyclohexyl alkyl group is bonded to the α-position carbon atom of the cyclohexane ring (in other words, the cyclohexyl alkyl group is a type in which the α-position carbon atom of the cyclohexane ring is bonded to the decalin ring) Particularly preferred are decalin derivatives in which the carbon atom bonded to is a cyclohexylalkyl group of the type bonded to the decalin ring. Specific examples of compounds represented by the above general formula [] are: Ya ceremony Bis(1-cyclohexylethyl) represented by
decalin, formula Ya ceremony Bis(1-methyl-1-cyclohexylethyl)decalin, represented by the formula Ya ceremony Bis(1-cyclohexylethyl) represented by
Methyldecalin, formula Ya ceremony Bis(1-methyl-1-cyclohexylethyl)methyldecalin, represented by the formula Tris(1-cyclohexylethyl)decalin, represented by the formula Ya ceremony Bis(cyclohexylmethyl)decalin, represented by the formula Ya ceremony Bis(cyclohexylmethyl)methyldecalin, represented by the formula Examples include tris(cyclohexylmethyl)decalin, which is represented by In addition, cyclohexyl alkyl groups bonded to the decalin ring include those in which the carbon atom at the α position is bonded to the decalin ring, as well as those in which the carbon atom at the β or γ position is bonded to the decalin ring (in other words, the cyclohexyl alkyl group is bonded to the decalin ring). bonded to the decalin ring via two or three carbon atoms). Furthermore, as component (B), in addition to the above-mentioned one in which two or more cyclohexyl alkyl groups are bonded to a decalin ring, a decalin derivative in which at least two cyclohexyl groups are bonded to a decalin ring, or at least one cyclohexyl alkyl group It is also possible to use decalin derivatives in which at least one cyclohexyl group is bonded to a decalin ring. Here, 1 to 3 alkyl groups having 1 to 4 carbon atoms may be introduced into these cyclohexane rings. Specific examples of these compounds include the formula

【Formula】ya expression Dicyclohexyldecalin, represented by the formula Examples include 1-cyclohexylethyl (cyclohexyl)decalin, which is represented by In producing such component (B), there are no particular restrictions and various methods can be used. For example, to produce the decalin derivative represented by the general formula [] above, naphthalene or its derivatives are usually reacted with alkenylbenzene such as styrene or its derivatives in the presence of an appropriate catalyst, and the resulting reaction product is It is obtained by dividing into various fractions by vacuum distillation or the like, and hydrogenating a predetermined fraction (particularly one in which two or more molecules of alkenylbenzene are bonded to naphthalene or the like). Catalysts that can be used here include Friedel-Crafts catalysts such as sulfuric acid and aluminum chloride, heteropolyacids or salts thereof such as phosphotungstic acid, silicotungstic acid, phosphomolybdic acid, and silicomolybdic acid, activated clay, acid clay, Examples include solid catalysts such as silica alumina, solid phosphoric acid, ion exchange resins, titania, and zeolites. The traction drive fluid of the present invention contains the above-mentioned (A) component and (B) component as main components, and also contains 100%
The kinematic viscosity at °C is 3 cSt or more. If component (A) above is used alone as a traction drive fluid, the traction coefficient, especially at high temperatures, is low, so when the oil temperature rises, slipping occurs on the power transmission surface of the traction drive device. There is a problem that power cannot be transmitted. On the other hand, when component (B) is used alone as a traction drive fluid, there is no problem at high temperatures, but the viscosity is high below room temperature, which causes problems such as increased energy loss due to stirring and poor lubrication. be. However, like the traction drive fluid of the present invention, the (A) component and (B)
When the components are mixed so that the kinematic viscosity at 100°C is 3 cSt or more, the viscosity is relatively low and the traction coefficient is high over a wide range from low to high temperatures, which eliminates problems such as low-temperature fluidity and oil film breakage at high temperatures. It has excellent overall performance. Moreover, the present invention provides a remarkable improvement in the traction coefficient (synergistic effect) by mixing the components (A) and (B).
The present invention provides an excellent traction drive fluid based on the completely new knowledge that the following results can be obtained. It is generally known that the traction coefficient has additivity as shown in the following equation (ASLE
Trans.13, 105-116 (1969)), f = 〓 ⁱ Cifi Ci: Mixing ratio of i component fi: Traction coefficient of i component f: Traction coefficient of mixture Also, there is a very small synergistic effect (about 2 to 3%) (SAE 710837 (1971)), but there are no known examples where the value is greater than the value of each component before mixing, or more than 10% greater than the weighted average, as in the present invention. do not have. In the present invention, there is no particular restriction on the mixing ratio of components (A) and (B), and in short, the kinematic viscosity at 100°C is
It may be determined to be 3.0 cSt or more, preferably 3.6 to 10.0 cSt. Specifically, it varies depending on the types of components (A) and (B) used, etc., but cannot be unambiguously determined.
Usually, 5 to 250 parts of component (B) is added to 100 parts by weight of component (A).
It may be blended in an amount of 8 to 150 parts by weight, preferably 8 to 150 parts by weight. Here, even if the main components are both components (A) and (B), the kinematic viscosity at 100℃ is 3 cSt.
If it is less than that, it will not be possible to ensure the rolling fatigue life of the traction drive device to exceed the rating, and long-term operation will be impossible. The rolling fatigue life of a rolling contact surface largely depends on the relationship between the surface roughness of both contact surfaces and the thickness of the oil film formed there, and this relationship is known as the oil film parameter Λ. Regarding the relationship between Λ and surface fatigue, it is said that if 0.9 < Λ, the life will be longer than estimated (Machine
Design 7, 102 (1974)). Based on the above, if we calculate the case where it is applied to an actual bearing as an example of the raceway, it is found that if the viscosity is 3.0 cSt or more, preferably 3.6 cSt or more at the operating temperature (100°C), then at least the rated It is possible to secure a rolling fatigue life that exceeds the (design value). In other words, it is necessary to blend so that the strength at 100°C is 3.0 cSt or more, preferably 3.6 cSt or more. Furthermore, when used in automobiles, the pour point is preferably -30°C or lower to enable smooth starting at low temperatures. As mentioned above, the traction drive fluid of the present invention contains both components (A) and (B) as main components, but various additives may be added as necessary. You can also do that. [Effects of the Invention] As described above, the traction drive fluid of the present invention exhibits a high and stable traction coefficient over a wide temperature range from low to high temperatures, and has an especially improved traction coefficient at high temperatures. be. Furthermore, since it has excellent overall performance as a traction drive fluid, it is widely used in various mechanical products such as continuously variable transmissions for automobiles and industrial use, and even hydraulic equipment. [Example] Next, the present invention will be explained in more detail with reference to Examples. The traction coefficients in Examples and Comparative Examples were measured using a two-cylinder friction tester. In other words, one of the adjacent cylinders of the same size (diameter 52 mm, thickness 6 mm, driven side is a tycoon type with a radius of curvature of 10 mm, and the driving side is a flat type without crowning) is held at a constant speed (1500 rpm), and the other is held at a constant speed (1500 rpm).
Rotate continuously from 1500rpm to 1750rpm, apply a load of 7kg to the contact area of both cylinders with a spring,
The tangential force generated between the two cylinders, that is, the traction force, was measured to determine the traction coefficient. This cylinder was made of bearing steel SUJ-2 with a mirror finish, and the maximum Hertzian contact pressure was 112 Kgf/mm ² . In addition, when measuring the relationship between traction coefficient and oil temperature, the oil temperature was varied from 40℃ to 140℃ by heating the oil tank with a heater.
This is a plot of the relationship between traction coefficient and oil temperature at a slip rate of 5%. Production Example 1 (Production of Component (A)) 1000 g of tetralin and 300 g of concentrated sulfuric acid were placed in the glass flask of step 3, and the temperature inside the flask was cooled to 0° C. in an ice bath. Next, 400 g of styrene was slowly added dropwise into the mixture over 3 hours while stirring, and the reaction was completed by further stirring for 1 hour. After that, stop stirring, leave it to stand still, and separate the oil layer.
After washing three times each with 500 cc of a specified aqueous sodium hydroxide solution and 500 cc of saturated saline, it was dried over anhydrous sodium sulfate. Next, unreacted tetralin was removed by distillation, followed by vacuum distillation to obtain 750 g of a fraction with a boiling point of 135-148°C/0.17 mmHg. As a result of analyzing this fraction, it was confirmed that it was a mixture of 1-(2-tetralyl)-1-phenylethane and 1-(1-tetralyl)-1-phenylethane. Put 500cc of this distillate into autoclave 1,
Further, 25 g of a 5% by weight ruthenium-carbon catalyst for hydrogenation (manufactured by Nippon Engelhard) was added, and hydrogenation was carried out at a hydrogen pressure of 50 Kg/cm ² and a reaction temperature of 200° C. for 4 hours. After cooling, the reaction solution was filtered to separate the catalyst. After stripping the light components from the liquid, analysis revealed that the hydrogenation rate was over 99.9% (confirmed by NMR analysis), and this product was 1-(2-decalyl)-1.
-Cyclohexylethane and 1-(1-decalyl)-
It was confirmed that it was a mixture with 1-cyclohexylethane. The specific gravity of the resulting mixture is 0.94
(15/4℃), the kinematic viscosity is 35.76cSt (40℃),
4.709cSt (100℃), and the refractive index n ^20/D is
It was 1.5040. Production example 2 (Production of component (B)) 3 equipped with a reflux condenser, thermometer and stirrer
896 g (7 moles) of naphthalene in a four-necked flask.
and 44.8 g of a heteropolyacid catalyst in which 17% by weight of phosphotungstic acid was supported on silica gel.
Heat to 150℃ and add 1092g (10.5g) of styrene while stirring.
mol) was added dropwise over 8 hours. After the dropwise addition was completed, the mixture was further stirred at 150° C. for 30 minutes to complete the reaction.
Immediately after the reaction was completed, the catalyst was removed and the liquid was distilled under reduced pressure to obtain about 800 g of a fraction with a boiling point of 230-250°C/0.6 mmHg. Analysis of this fraction confirmed that the main component was bis(1-phenylethyl)naphthalene, a compound in which two molecules of styrene were added to naphthalene. Next, 500 g of this fraction was placed in autoclave 1, and 25 g of a hydrogenation catalyst similar to that used in Production Example 1 was added, followed by hydrogenation for 4 hours at a hydrogen pressure of 100 Kg/cm ² and a reaction temperature of 200°C. I did this. After cooling,
After separating the catalyst by passing through the reaction solution, nuclear magnetic resonance spectroscopy (NMR) analysis of the solution revealed that the hydrogenation rate was over 99%, indicating that bis(1-phenylethyl)naphthalene had not been directly nuclearly hydrogenated. It was confirmed that the main component was bis(1-cyclohexylethyl)decalin, which is a chemical compound. The kinematic viscosity of this product was 60 cSt (100°C), and the refractive index n ^{20 /D} was 1.5084. Example 1 78 parts by weight of the fluid containing 1-(2-decalyl)-1-cyclohexylethane as a main component (hereinafter referred to as "fluid A-1") obtained in Production Example 1 and the bis( Table 1 shows the properties of a fluid (hereinafter referred to as "mixed fluid-1") in which 22 parts by weight of a fluid containing 1-cyclohexylethyl) decalin as a main component (hereinafter referred to as "fluid B-1") was mixed. Further, the relationship between the traction coefficient and temperature of this mixed fluid-1 is shown in FIG. Example 2 Table 1 shows the properties of a fluid obtained by mixing 90 parts by weight of fluid A-1 and 10 parts by weight of fluid B-1 (hereinafter referred to as "mixed fluid-2"). Further, the relationship between the traction coefficient and temperature of this mixed fluid-2 is shown in FIG. Comparative Example 1 The properties of the fluid A-1 obtained in Production Example 1 are shown in Table 1, and the relationship between the traction coefficient and temperature of this fluid is shown in FIG. Comparative Example 2 The properties of fluid B-1 obtained in Production Example 2 are shown in Table 1, and the relationship between the traction coefficient and temperature of this fluid is shown in FIG.

[Table] Production example 3 (Production of component (A)) α-methylstyrene was added to the glass flask from step 3.
1000g and 40g of acid clay and 50g of mesityl oxide
g was added thereto, and the mixture was reacted at 140°C for 2 hours with stirring. After separating the catalyst from the reaction solution, unreacted α-methylstyrene and mesityl oxide were distilled off to obtain 900 g of a fraction with a boiling point of 125-130°C/0.2 mmHg. As a result of NMR analysis and gas chromatography analysis, this fraction was confirmed to be a mixture of 97% linear dimer and 3% cyclic dimer of α-methylstyrene. This fraction was hydrogenated and post-treated in the same manner as in Production Example 1 to obtain a traction drive fluid containing 2,4-dicyclohexyl-2-methylpentane as a main component. The specific gravity of this thing is 0.90 (15/4
℃), kinematic viscosity 20.20cSt (40℃), 0.580cSt
(100°C), and the viscosity index was 13. Example 3 2,4-dicyclohexyl-2 obtained in Production Example 3
- A fluid obtained by mixing 73 parts by weight of a fluid containing methylpentane as a main component (hereinafter referred to as "Fluid A-2") and 27 parts by weight of Fluid B-1 obtained in Production Example 2 (hereinafter referred to as "Mixed Fluid-3") ) is shown in Table 2. Further, the relationship between the traction coefficient and temperature of this mixed fluid-3 is shown in FIG. Comparative Example 3 The properties of fluid A-2 obtained in Production Example 3 are shown in Table 2, and the relationship between the traction coefficient and temperature of this fluid is shown in FIG. Note that Table 2 and FIG. 2 also show the properties of fluid B-1 for reference.

[Table] Production Example 4 (Production of component (B)) The reaction was carried out in the same manner as in Production Example 2, except that the catalyst was replaced with 150 g of activated clay that had been previously calcined at 220°C for 20 hours. . Immediately after the reaction was completed, the catalyst was separated and the unreacted naphthalene was distilled off from the liquid. The residue was analyzed and found to be 1.
It was confirmed that it was a mixture of 32% by weight of -phenyl-1-naphthylethane, 43% by weight of bis(1-phenethyl)naphthalene, and 23% by weight of tris(1-phenethyl)naphthalene. This mixture was hydrogenated using a Raney nickel catalyst (Raney nickel NDH, manufactured by Kawaken Fine Chemical Co., Ltd.) in the same manner as in Production Example 2 to produce 32% by weight of 1-cyclohexyl-1-decarylethane and bis(1-cyclohexylethyl). ) A fluid containing 43% by weight of decalin and 23% by weight of tris(1-cyclohexylethyl)decalin was obtained. Example 4 73 parts by weight of fluid A-1 obtained in Production Example 1 and the fluid obtained in Production Example 4 (hereinafter referred to as "Fluid B-2")27
A fluid mixed with parts by weight (hereinafter referred to as "mixed fluid-4")
That's what it means. ) are shown in Table 3. Further, the relationship between the traction coefficient and temperature of this mixed fluid-4 is shown in FIG. Comparative Example 4 The properties of fluid B-2 obtained in Production Example 4 are shown in Table 3, and the relationship between the traction coefficient and temperature of this fluid is shown in FIG. Note that Table 3 and FIG. 3 also show the properties of fluid A-1 for reference.

[Table] Production Example 5 (Production of component (A)) 500 ml of toluene, 150 g (2 moles) of pyridine, and cyclododecanol in a four-necked flask from Step 2.
Add 396 g (2 moles) of cyclohexane carbonyl chloride, and add 293 g (2 moles) of cyclohexane carbonyl chloride to 45 ~
The mixture was added dropwise over 2.5 hours at a temperature of 75°C, and the reaction was completed by further stirring for 1 hour. After cooling the reaction solution to room temperature, pyridine hydrochloride was suctioned off using a Nutsuie filter, and toluene was distilled off from the resulting solution. The residue was distilled under reduced pressure to obtain 445 g of a 160-170°C/0.2 mmHg fraction. . Analysis of this product confirmed that it was a cyclohexanecarboxylic acid ester of cyclododecanol. Example 5 86 parts by weight of the fluid containing cyclohexanecarboxylic acid ester of cyclododecanol obtained in Production Example 5 (hereinafter referred to as "Fluid A-3") and 14 parts by weight of Fluid B-2 obtained in Production Example 4 Table 4 shows the properties of the fluid obtained by mixing the above components (hereinafter referred to as "mixed fluid-5"). Further, the relationship between the traction coefficient and temperature of this mixed fluid-5 is shown in FIG. Comparative Example 5 Table 4 shows the properties of fluid A-3 obtained in Production Example 5, and FIG. 4 shows the relationship between the traction coefficient and temperature of this fluid. Note that Table 4 and FIG. 4 also show the properties of fluid B-2 for reference.

【table】 [Brief explanation of the drawing]

1, 2, 3, and 4 are graphs showing the relationship between the traction coefficient of the fluid and the temperature in the example and the comparative example.

Claims (1)

[Scope of Claims] 1 (A) a base oil with a kinematic viscosity of 8 cSt or less at 100°C and (B) a decalin ring containing (i) at least two cyclohexyl alkyl groups, (ii) at least two cyclohexyl groups, or (iii) A fluid for traction drive, characterized in that the main component is a decalin derivative formed by bonding at least one cyclohexyl alkyl group and at least one cyclohexyl group, and the fluid has a kinematic viscosity at 100°C of 3 cSt or more. 2. The traction drive fluid according to claim 1, wherein the (B) decalin derivative is blended in a ratio of 5 to 250 parts by weight to 100 parts by weight of the (A) base oil. 3. The traction drive according to claim 1, wherein (A) the base oil is a naphthenic base oil, an aromatic base oil, a paraffinic base oil, a silicone base oil, an ester base oil, or a mixture thereof. Fluid for use. 4 (B) The decalin derivative has the general formula [In the formula, R ¹ to ^{R 8} each represent hydrogen or an alkyl group having 1 to 4 carbon atoms, and p, q, r, and s each represent an integer of 1 to 3. Moreover, m and n are each integers of 0 to 3, and the sum of both is 2 or 3. ] The traction drive fluid according to claim 1, which is a compound represented by the following.