JP2740272B2 - Traction fluid lubricant - Google Patents

Description

The invention relates to the use of certain organosilicon compounds as lubricants, in particular in traction drives.

These lubricants can be used in various engineering applications, but are particularly useful in traction drives. Traction is broadly defined as the adhesive friction of an object on the surface over which it moves. A traction drive is a device that transmits torque from an input member to an output member based on traction between contacting elements, typically via a rolling action, via so-called point or line contact. Although the traction members are usually said to be in contact with each other, it is generally accepted that a fluid film is present therebetween. Almost all traction drives require fluid to remove heat, prevent wear of contact surfaces, and lubricate the bearings and other moving members associated with the drive. Thus, instead of rolling contact between the metals, there is a fluid film introduced into the contact zone and inserted between the metal members. The nature of this fluid determines the performance limits and the performance of the drive to a large extent. Most traction drives preferably have a traction coefficient higher than about 0.06, a viscosity in the range of about 4 to 20,000 mPa.s in a temperature range of 40 ° C. to −20 ° C., and good thermal and oxidative stability. Designed to operate with traction fluid. The fluid also
It must be non-corrosive to the normal materials of the structure and have good load bearing and low wear rate characteristics.

Mineral-based oils generally have a low coefficient of traction (friction), and therefore the maximum tangential force (tangential) that can be transmitted by a friction wheel when a given load is applied to the gear.
Due to the low force), it is a rather unsuitable lubricant for traction drives.

It has now been found that certain organosilicon compounds constitute good lubricants and traction fluids.
Accordingly, the present invention provides a compound of the general formula I: (R ¹ O) _m SiR ² _4-m I wherein m is 2, 3 or 4, and each R ¹ group is optionally an alkyl group having 1 to 6 carbon atoms. Represents a cyclohexyl group substituted with, and R ² represents an alkyl having up to 4 carbon atoms.
However, when each R ¹ group is an unsubstituted cyclohexyl group, m is 2 or 3), and relates to a lubricant containing an organosilicon compound which is liquid at room temperature, particularly to a traction fluid. The alkyl group is linear or branched irrespective of whether it is present as an R ² group or a substituent in the R ¹ group, and preferably has 1 to 6 carbon atoms, When a group having up to 4 is selected, a particularly suitable combination of physical properties and material cost is obtained.

Suitable silicone esters are of formula II: (Wherein, R ³ represents H or methyl, m is 2, 3 or 4, provided that when the R ³ group is H, m is 2 or 3). A particularly preferred embodiment is cyclohexyloxysilane which is liquid at room temperature.

These organic - silicon compounds are known compounds, for example, suitable reaction of an alcohol and a chlorosilane, ^{_{namely: Cl m SiR 2 4-m}} + mR 1 OH = R 2 4-m Si (OR 1) known as _m Can be prepared. It will be appreciated that the optimum reaction conditions will depend to some extent on the specific types of R ¹ and R ² , and in the case where R ¹ is cyclohexyl and R ² is methyl (preferred), the resulting hydrogen chloride is To remove, in an organic solvent (eg dichloromethane) in the presence of a base (eg pyridine or triethylamine)
It has proven convenient to carry out the reaction at a temperature not exceeding 25 ° C. As is common in the reaction of chlorosilanes, the process desirably uses an inert atmosphere (eg, nitrogen) using a dry reagent to minimize hydrolysis of the reagent.
Should be done below. It is convenient to purify the product using a thin film evaporator.

The viscosity properties of the organosilicon compounds are very suitable for use in friction wheel transmissions (traction drives) which can be used, for example, in admixture with conventional grease thickeners. Many such materials commonly used to increase the viscosity of mineral oils to lubricating viscosities,
For example, metal soap, synthetic polymer, organosiloxane,
Organic and inorganic compositions such as clay, bentonite and colloidal silica can be mentioned. As for the viscosity characteristics of the compound used for the traction drive, it is preferable that the compound can be used at −30 to 150 ° C. To this end, the ester compounds in the lubricants according to the invention advantageously have a viscosity at 40 ° C. of at most 1000, preferably 250 mm ² / s, at 100 ° C. of at least 1, preferably 3 mm ² / s.

Such compounds can be used as lubricants in various engineering applications. The invention particularly relates to the use of these organosilicon compounds as traction fluids and to the operation of traction drives in which such compounds form traction fluids, since the compounds exhibit excellent lubrication performance in traction drives.

The organosilicon compound of the present invention can be used as a lubricant per se. The compound may be mixed with other lubricants such as mineral or synthetic oils, viscosity index improvers,
Various additives such as pour point depressants, dispersants, detergents, antioxidants and the like may be added. Mixtures that are particularly useful for traction fluids are blends with polyolefins, especially polyalphaolefins, especially polyisobutylene, because the presence of this polymer effectively increases the traction coefficient of the fluid blend. is there. The molecular weight of such a polyolefin blend component is
A range of from 500 to 10,000 is suitable, a specific example of a suitable polyisobutylene is "Hyvis", and the proportion of polyolefin ranges from 0 to 70% by weight.

The following examples illustrate the preparation of representative compounds used in the present invention and their tribological properties.

Example 1 Dimethyldi (cyclohexyloxy) silane A solution of cyclohexanol (1240 g, 12.4 m) and triethylamine (1250.0 g, 12.4 m) dissolved in dichloromethane (6 L) was stirred at 0 to 5 ° C. in a dry nitrogen atmosphere.
Dimethyldichlorosilane (800 g, 6.2 m) was added dropwise over 3-4 hours while maintaining the temperature of the reaction mixture below 10 ° C. After the addition is complete, the mixture is left at room temperature for a further 18
Stirred for hours. Thereafter, a white precipitate of triethylamine hydrochloride was passed through and washed with dichloromethane (500 ml). The organic phase solutions were combined, washed with water (2 × 2 L), and the solvent was distilled off under reduced pressure at 30 ° C. to obtain a pale yellow oil (1750 g). KDL-4
Traces of residual solvent and unreacted alcohol were removed by evaporation at 40 ° C. (1.0 mmHg) (133.3 Pa) using a thin film evaporator. The oily residue was then distilled at 120 ° C. (pressure 0.4 mmHg) (53.3 Pa) using the same apparatus, and dimethyldi (cyclohexyloxy) silane (1200
g, 75.5%, analyzed by GLC using area percentage calculation 97.6
% W / w).

Example 2 Methyltri (cyclohexyloxy) silane A solution of cyclohexanol (1240 g, 12.4 m) and triethylamine (1273.0 g, 12.4 m) dissolved in dichloromethane (6 L) was stirred at 0 to 5 ° C. in a dry nitrogen atmosphere. Methyltrichlorosilane (620.0 g, 4.15 m) was added dropwise over 3-4 hours, while maintaining the temperature of the reaction mixture below 10 ° C. After the addition is completed, the mixture is further
Stir for 18 hours. Thereafter, a white precipitate of triethylamine hydrochloride was passed through and washed with dichloromethane (500 ml).
The organic phase solutions were combined, washed with water (2 × 2 L), and the solvent was distilled off under reduced pressure at 30 ° C. to obtain a pale yellow oil (1543.3 g). KDL
-4 traces of residual solvent and unreacted alcohol were removed by evaporation at 40 ° C. (pressure 1.00 mmHg) (133.3 Pa) in a thin film evaporator. Next, the oily residue was distilled at 160 ° C. (0.2 mmHg) (26.7 Pa) using the same apparatus, and methyltri (cyclohexyloxy) silane (1116.0) was obtained as a colorless oily substance.
g, 79.0%, analyzed 96.5 in GLC using area percentage calculation
% W / w).

Example 3 Dimethyldi (methylcyclohexyloxy) silane A solution of methylcyclohexanol (1400.0 g, 12.3 m) and triethylamine (1250.0 g, 12.4 m) dissolved in dichloromethane (6 L) was stirred at 0 to 5 ° C. in a dry nitrogen atmosphere. . Add 3 parts of dimethyldichlorosilane (800.0g, 6.2m)
The addition was added dropwise over ４4 hours, during which time the temperature of the reaction mixture was maintained below 10 ° C. After the addition was completed, the mixture was stirred at room temperature for another 18 hours. Thereafter, a white precipitate of triethylamine hydrochloride was passed through and washed with dichloromethane (500 ml). The organic liquids were combined, washed with water (2 × 2 L), and the solvent was distilled off under reduced pressure at 30 ° C. to obtain a pale yellow oil (1624 g). 40 ℃ (pressure 1.00mmHg) with KDL-4 thin film evaporator (133.3
Traces of residual solvent and unreacted alcohol were removed by evaporation at Pa). Next, at 120 ° C (0.4 mmHg) (53.3
The oily residue was distilled using the same apparatus at 540 Pa) and analyzed by GLC as a mixture of isomers using dimethyldi (methylcyclohexyloxy) silane (1340 g, 76.0%, area percent calculation) as a colorless oil 99 % W / w).

Example 4 Methyltri (methylcyclohexyloxy) silane A solution of methylcyclohexanol (1260.0 g, 11.0 m) and triethylamine (1130.0 g, 11.0 m) dissolved in dichloromethane (6 L) was stirred at 0 to 5 ° C. in a dry nitrogen atmosphere. . Methyltrichlorosilane (550.0 g, 3.68 m) was added dropwise over 3-4 hours, while maintaining the temperature of the reaction mixture below 10 ° C. After the addition was completed, the mixture was stirred at room temperature for another 18 hours. Thereafter, a white precipitate of triethylamine hydrochloride was passed through and dichloromethane (500 ml) was added.
Washed with. Combine the organic phase solutions, wash with water (2 x 2 L),
The solvent was distilled off under reduced pressure at ° C to obtain a pale yellow oil (1202 g). 40 ℃ with KDL-4 thin film evaporator (pressure 1.00mmHg) (13
Traces of residual solvent and unreacted alcohol were removed by evaporation at 3.3 Pa). Next, 180 ℃ (0.4mmHg)
Distill the oily residue using the same apparatus at (53.3 Pa), methyltri (methylcyclohexyloxy) silane as a colorless oil (1025.1 g, 72.8%, GLC as a mixture of isomers using area percentage calculation) An analytical value of 99.3% w / w) was obtained.

Example 5 Tetra (methylcyclohexyloxy) silane Methylcyclohexanol (1560 g, 13.7 m) and triethylamine (1380 g, 13.6 m) were added to dichloromethane (6 L).
Was stirred at 0-5 ° C. in a dry nitrogen atmosphere. Silicon tetrachloride (577.0 g, 3.4 m) was added dropwise over 3-4 hours, while maintaining the temperature of the reaction mixture below 10 ° C. After the addition was completed, the mixture was stirred at room temperature for another 18 hours. Thereafter, a white precipitate of triethylamine hydrochloride was passed through and washed with dichloromethane (500 ml). The organic phase solutions were combined, washed with water (2 × 2 L), and the solvent was distilled off at 30 ° C. under reduced pressure to obtain a pale yellow oil (1595.0 g). Traces of residual solvent and unreacted alcohol were removed by evaporation at 40 ° C. (pressure 1.00 mmHg) (133 Pa) in a KDL-4 thin film evaporator. Next, the oily residue was distilled at 185 ° C. (0.4 mmHg) (53.3 Pa) using the same apparatus, and tetra (methylcyclohexyloxy) silane (1190.3 g, 73.
5%, G as a mixture of isomers using area percentage calculation
An LC analysis of 99.6% w / w) was obtained.

Example 6 Friction Coefficient Measurements All friction measurements were performed on a two disc machine. The hardened steel disc is fixed to the ends of the two shafts in tangential contact with each other. 0-200k
A radial force may be applied to the disc along with the gf load. Each disk is driven by an electric motor. The rotational speeds of the two disks are different so that a slip occurs.

A measuring device for indicating the transmitted friction torque is mounted between the electric motor and the shaft supporting the lower object under test. The measuring device is a gear dynamometer having a pendulum that oscillates from a vertical equilibrium position when power is transmitted, and the sine of the tilt angle is an indicator of torque. Torque measurements are pre-calibrated through the design and dimensions of the instrument. The coefficient of friction is the measured torque divided by the product of the radial force and the radius of the lower disk.

The two disks used were 50.0 mm in diameter, the upper disk was 3 mm wide and the lower disk was 10 mm wide.
The top shaft speed was 606 rpm and the average tangent (or surface) speed was 1.48 ms- ¹ . The slip used is 9.1
%Met.

All experiments were performed at room temperature (21 ° C. ± 2 ° C.). Friction readings were obtained at loads equal to Hertzian stresses of 0.69, 0.97, 1.19 and 1.38 GPa.

The coefficient of friction of the compounds is shown in the table below. In the case of the compound of Example 1 (mp = 48-50 ° C.), these coefficients are 21 (±
2) Determined on supercooled fluid at ° C.

 The table also shows the kinematic viscosity characteristics of each compound.

Tetra (cyclohexyloxy) silane was also synthesized, but the above frictional properties could not be measured because the material was solid up to 71 ° C.

Claims (7)

(57) [Claims] 1. A compound of the general formula I: (R ¹ O) _m SiR ² _4-m I wherein m is 2, 3 or 4 and each R ¹ group is optionally an alkyl group having 1 to 6 carbon atoms. Represents a cyclohexyl group substituted with, and R ² represents an alkyl having up to 4 carbon atoms.
However, when each R ¹ group is an unsubstituted cyclohexyl group, m is 2 or 3), and a lubricant containing an organosilicon compound which is liquid at room temperature. 2. An organic silicon compound having the general formula II: (Wherein, R ³ represents H or methyl, m is 2, 3 or 4, provided that when R ³ is H, m is 2 or 3). 2. The lubricant according to 1. 3. A maximum of organosilicon compound 40 ° C. 1000 mm ² /
3. The lubricant according to claim 1, wherein the lubricant has a kinematic viscosity at 100 ° C. of at least 1 mm ² / s. 4. A lubricant composition comprising the organosilicon compound according to any one of claims 1 to 3 as a main component. 5. A traction fluid comprising the organosilicon compound according to claim 1. 6. A traction fluid composition comprising the organosilicon compound according to any one of claims 1 to 3 as a main component. 7. A method for operating a traction drive, comprising using the traction fluid according to claim 5 or the traction fluid composition according to claim 6.