JPH066713B2 - Hydraulic fluid - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a hydraulic fluid used in hydraulically operated devices, and particularly to a hydraulic fluid having excellent rubber swelling properties and suitable as a brake fluid for automobiles.

[Conventional technology]

Brake fluids, which are hydraulic fluids used for automobile hydraulic brakes, are required to have a high boiling point, excellent low-temperature characteristics, and no adverse effects on sealing materials and metals from the viewpoint of safety. In accordance with the required level of characteristics of the above, three kinds of DOT-3, DOT-4 and DOT-5 are standardized in the United States by FMVSS (US Federal Motor Vehicle Safety Standard) No.116.

DOT-3 or DOT containing polyalkylene glycol and its alkyl ethers or ester borate
-4 equivalent brake fluid has a relatively high hygroscopicity and a large boiling point drop due to moisture absorption, so there was a risk of causing a vapor lock phenomenon when used under severe conditions.

As a brake fluid that eliminates the drawbacks of brake fluids equivalent to DOT-3 and DOT-4, DOT-based on silicone oil
5 equivalent brake fluid has been proposed (SAE Report 74012
8).

[Problems to be solved by the invention]

However, since silicone oil has excellent viscosity characteristics and low-temperature fluidity and is a stable compound, it is an excellent base material for brake fluid, but it does not shrink the rubber used as a sealant in the brake system, and also has a water-containing capacity. Since there is almost no water, when a small amount of water is mixed in the brake fluid, it has the drawback of separating the water and causing metal corrosion. As an attempt to improve these drawbacks, addition of Estes (JP-A-49-49068, JP-A-56-61495) and addition of phosphoric acid esters (JP-A-52-53782) are being investigated. Even though the rubber swelling ratio of the silicone oil could be improved, the hardness of the rubber was largely changed and the rubber had a defect that the rubber was damaged during actual use. The use of a polyether-modified silicone oil (JP-A-57-70196) has also been proposed, but when it is used in combination with a silicone oil, the compatibility decreases and it separates at low temperature, or it is used alone. When used, there was a problem that the viscosity at low temperature became too high.

The present invention is to solve the problems of the conventional ones, and by combining a specific compound and a silicone oil, it has an appropriate rubber swelling property, has little change in hardness of rubber, and has low temperature characteristics. Is also excellent and aims to provide a hydraulic fluid that meets the DOT-5 brake fluid specifications.

[Means for solving problems]

The present invention comprises 1 to 80% by weight of one or more compounds selected from the compounds represented by the following formula (I) or formula (II):
And a hydraulic fluid containing 20 to 99% by weight of silicone oil.

(Wherein R ¹ and R ⁴ are each 6 to 28 carbon atoms
A branched aliphatic hydrocarbon group, R ² , R ³ and R ⁵ are each a straight or branched aliphatic hydrocarbon group having 1 to 28 carbon atoms, and R ⁶ is a methylene group or an ethylene group. , AO is an oxyalkylene group having 2 to 4 carbon atoms,
k, m, and n are average addition mole numbers of alkylene oxide having 2 to 4 carbon atoms, and k and m are 0 to 0, respectively.
10, and k + m is 1 to 20, and n is 1 to 10. In the formulas [I] and [II], the branched aliphatic hydrocarbon group represented by R ¹ and R ⁴ is an isohexyl group, an isoheptyl group, an isooctyl group, an isononyl group, an isodecyl group, an isoundecyl group, Isododecyl group, isotridecyl group, isotetradecyl group, isopentadecyl group, isohexadecyl group, isoheptadecyl group, isooctadecyl group, isononadecyl group, isoeicosyl group, isoheneeicosyl group, isodocosyl group, isotricosyl group, isotetracosyl group, etc. is there.

The aliphatic hydrocarbon group represented by R ² , R ³ and R ⁵ is a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group or an undecyl group. , Dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group,
There are eicosyl group, heneicosyl group, oleyl group and the like, which may have a straight chain or a branched chain.
R ¹ , R ² , R ³ and R ⁴ may be the same or different.

Examples of the oxyalkylene group having 2 to 4 carbon atoms represented by (AO) include oxyethylene group, oxypropylene group, oxybutylene group and oxytetramethylene group,
These indicate that they are adducts of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, etc., and these alkylene oxides may or may not be added individually, or may be added individually or in a mixed state, and in a mixed state. In the case of addition, it may be added randomly or in a block form.

The compound of the formula [I] is prepared by using the amine having R ¹ N or R ¹ R ² N as a residue, or an alkylene oxide adduct thereof as a raw material, in the presence of a sodium agent, and having 1 to 1 carbon atoms.
Obtained by reacting 26 alkyl halides.

The compound of the formula [II] can be obtained by reacting an amine having R ⁴ R ⁵ N as a residue or an alkylene oxide adduct thereof as a raw material with a dihalogenated methylene or dihalogenated ethylene in the presence of a sodium agent.

The reason why the average number of moles of alkylene oxide added is limited to 10 moles or less for the compounds of the formulas [I] and [II] is that the viscosity at low temperature increases and the silicone oil, olefin polymerized oil, etc. This is because the compatibility with the other brake fluid compounding bases decreases, and turbidity or separation occurs at low temperatures. The average number of moles of alkylene oxide added is
When the amount is 10 mol or less, a brake fluid meeting the DOT-5 standard can be obtained by varying the type and order of addition of the alkylene oxide to be added and the type and amount of other compounding base.

R ¹ and R ⁴ are limited to the aliphatic hydrocarbon group having a branched chain having 6 to 28 carbon atoms, because the compatibility with other bases used in the brake fluid when the carbon number is less than 6 is limited. This is because turbidity and separation occur at low temperature, and in the case of a straight-chain aliphatic hydrocarbon group or a branched chain aliphatic hydrocarbon group having more than 28 carbon atoms, the freezing point becomes high and This is because it becomes cloudy or coagulates at the time and cannot be used as a base for brake fluid.

The second component of the hydraulic fluid of the present invention, the silicone oil, is an oily organosilicon compound polymer having a siloxane bond and preferably has a kinematic viscosity at 25 ° C. of 5 to 100 cSt. Such silicone oils include, in addition to dimethylpolysiloxane and methylphenylpolysiloxane, compounds having a hydroxyl group or a vinyl group, such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, and undecanol. , Dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, otakudecanol, nonadecanol, eicosanol, oleyl alcohol and other alcohols and their alkylene oxide adducts, polyoxyalkylene glycol monoaryl ethers , Polyoxyalkylene glycol monoalkyl monoaryl ether, butene, pentene, hexene, hepsene, o Ten, nonene, decene,
Modified silicone obtained by reacting one or more compounds selected from olefins such as undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, heptadecene and octadecene olefins with siloxane having SiOCH ₃ or SiH group in the molecule. Oil etc. are included.

The hydraulic fluid of the present invention contains 1 to 80% by weight of one or more compounds selected from the compounds represented by the formulas [I] and [II] and 20 to 99% by weight of silicone oil as essential components. Here, the content of the compounds represented by the formulas [I] and [II] in the working fluid is 1 to
The range of 80% by weight is limited because if it is less than 1% by weight, the effect of improving the rubber swelling property of the silicone oil and the effect of improving the viscosity characteristics are not obtained, and if it exceeds 80% by weight, the rubber swelling property is Is too large.

In addition to the above essential components, the hydraulic fluid of the present invention may contain other components as a brake fluid base. in this case,
Since it contains the compound represented by the formula [I] or the formula [II],
Polyethylene oil that is incompatible with silicone oil can be blended as another brake fluid base. As the polyether oil used here, a polyalkylene glycol monoalkyl ether having a molecular weight of 500 or less is preferable from the viewpoint of low temperature viscosity characteristics. If necessary, polybutene, α
-Olefin polymerized oils, dibasic acid ester oils, polyol ester oils, phosphoric acid ester oils, higher alcohols and the like can also be added as part of the base.

In addition to the above-mentioned base, the hydraulic fluid of the present invention may optionally contain various commonly used additives such as an antioxidant, a rust preventive and a pH adjuster.

The hydraulic fluid thus obtained is suitable as a brake fluid for automobiles and the like, and can be used not only as a brake fluid but also as a clutch hydraulic fluid and other hydraulic fluids.

〔The invention's effect〕

Since the hydraulic fluid of the present invention contains a compound having a special structure and a silicone oil as components, it exhibits appropriate rubber swelling property, small change in rubber hardness, and excellent low temperature characteristics. It is also low and has quality as a brake fluid equivalent to DOT-5.

Examples of the Invention Hereinafter, the present invention will be described with reference to Examples.

Production Example 1 (Production of [I] Formula Compound of No. 1 in Table 1) 1850 g (10 mol) of diisohexylamine in an airtight reaction vessel.
1,2-butylene oxide 144 in a nitrogen gas atmosphere.
0 g (20 mol) was subjected to an addition reaction at 110 ° C to 130 ° C at 0.5 to 5.0 Kg / cm ² to obtain a crude polyether. Sodium methoxide (594 g, 11 mol) was added to this crude polyether, and methanol was removed under nitrogen atmosphere at 30 to 50 mmHg at 120 ° C. for 2 hours to sodiumate the terminal hydroxyl groups of the polyether. Then, after reacting at the same temperature through methyl chloride gas until the alkalinity of the reaction product becomes 1.0 or less,
The salt formed is filtered off to form a diether type polyetheramine.
I got 3000g. This product had a hydroxyl number of 2.3 and a dietherification rate of 98.6%.

Production Example 2 (Production of [II] Formula Compound of NO. 2 in Table 1) 2410 g (10 mol) of diisooctylamine in an airtight reaction vessel.
And 4 g of calcium hydroxide, and under a nitrogen gas atmosphere, 440 g of ethylene oxide (10 mol) and 1160 of propylene oxide.
g (20 mol) of the mixture, 110 ℃ ~ 130 ℃, 0.5 ~ 5.0K
Random type crude polyether 381 by addition reaction at g / cm ²
I got 0g. To 2005 g (5 mol) of this crude polyether was added 297 g (5.5 mol) of sodium methoxide, and the terminal hydroxyl groups of the polyether were sodiumated in the same manner as in Example 1.
Then, at the same temperature, 234 g of methylene chloride (2.75 mol) was added and reacted. After the reaction was carried out until the alkalinity became 1.0 or less, the produced salt was filtered off to obtain 3600 g of bis (glycol ether) formal. This product had a hydroxyl number of 1.2 and a dietherification rate of 99.1%.

Hereinafter, the diether compounds shown in Table 1 were obtained by the same method.

Example 1 The compound of the formula [I] or the formula [II] produced as described above and the compound thereof and the silicone oil were blended so as to have the composition shown in Table 1 and the comparative product,
Kinematic viscosity and rubber swelling property (120 ° C x 70 hours) according to JIS K-223
3 Measured according to the "Testing method for brake fluid for automobiles". The results are shown in Table 1.

In Table 1, modified silicone oil A and modified silicone oil B
Each represents a compound having the following structure.

Modified silicone oil A Modified silicone oil B As is clear from the results in Table 1, Nos. 4 to 7 were not suitable as hydraulic fluids because the rubber swelling ratio could not satisfy the JIS standard range of 0.5 to 5.0%. When a straight-chain aliphatic alcohol is used (NO.8), when the number of moles of alkylene oxide added is large (NO.9) and when an alcohol having less than 6 carbon atoms is used as the raw material alcohol (NO.10) It is not suitable as a hydraulic fluid because it solidifies at low temperature (NO.8) and has poor compatibility with silicone oil (NO.9, NO.10).
Further, it can be seen that the conventional product (NO. 11) containing known tributyl formate as a rubber swelling agent has a large change in hardness of rubber and has a problem as a brake fluid.

On the other hand, the product of the present invention satisfies the specifications of the brake fluid in each item of kinematic viscosity and rubber swelling property, and it can be seen that it is useful as a hydraulic fluid.

Example 2 A brake fluid was prepared by mixing 0.01 part by weight of benzotriazole with 100 parts by weight of the sample No. 1 prepared in Example 1 to prepare FM.
The test was conducted according to VSS NO.116. The results are shown in Table 2.

From the results in Table 2, it is understood that the products of the present invention satisfy the specifications of the brake fluid and are excellent as the brake fluid.

Claims (5)

[Claims] 1. A working fluid containing 1 to 80% by weight of one or more compounds selected from the compounds represented by the following formula [I] or [II] and 20 to 99% by weight of silicone oil. (Wherein R ¹ and R ⁴ are each 6 to 28 carbon atoms
A branched aliphatic hydrocarbon group, R ² , R ³ and R ⁵ are each a straight or branched aliphatic hydrocarbon group having 1 to 28 carbon atoms, and R ⁶ is a methylene group or an ethylene group. , AO is an oxyalkylene group having 2 to 4 carbon atoms,
k, m, and n are average addition mole numbers of alkylene oxide having 2 to 4 carbon atoms, and k and m are 0 to 0, respectively.
10, and k + m is 1 to 20, and n is 1 to 10. ) 2. R ¹ and R ⁴ are an isohexyl group, an isoheptyl group, an isooctyl group, an isononyl group, an isodecyl group,
Isoundecyl group, isododecyl group, isotridecyl group, isotetradecyl group, isopentadecyl group, isohexadecyl group, isoheptadecyl group, isooctadecyl group, isononadecyl group, isoeicosyl group, isoheneicosyl group, isodocosyl group, isotricosyl group, or The hydraulic fluid according to claim 1, which is an isotetracosyl group. 3. R ² , R ³ and R ⁵ are a methyl group, an ethyl group,
Propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group The hydraulic fluid according to claim 1 or 2, wherein the hydraulic fluid is an eicosyl group, a heneicosyl group, or an oleyl group. 4. The hydraulic fluid according to any one of claims 1 to 3, wherein AO is an oxyethylene group, an oxypropylene group, an oxybutylene group, or an oxytetramethylene group. 5. The hydraulic fluid according to any one of claims 1 to 4, wherein the silicone oil has a kinematic viscosity at 25 ° C. of 5 to 100 cSt.