JP2925038B2 - Brake fluid made of a glycol compound as the main component and preventing metal corrosion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for preventing at least one glycol compound essentially as a main component, and a brake fluid containing at least one glycol compound as a basic component, in which metal corrosion is prevented. The present invention relates to a brake fluid comprising an agent.

[0002]

2. Description of the Related Art As is well known, currently used brake fluids are types DOT3, DOT4 and DOT5.
[DOT = Department of Transportatio
n, USA)]. The properties required for such liquids are described in US Federal Motor Vehicle Safety Standard 116 (FMVSSN).
o, 116) and American Society of Automotive Engineers J1703 (S
AE / J1703). As we know,
The most important properties of the brake fluid are its dry boiling point (reflux boiling point─also called dry or more simply the boiling point), wet boiling point (reflux boiling point─also called wet) and viscosity at −40 ° C. Is included. The preferred request value
These are summarized below.

[0003] DOT3 DOT4 Dot5 viscosity up to 1500 mm ² / s up to 1800 mm ² / s up to 900 mm ² / s for example British patents in boiling Min 205 ° C. Min 230 ° C. Min 260 ° C. wet boiling point minimum 140 ° C. Min 155 ° C. Min 180 ° C. -40 ° C. No. 850,990 and U.S. Pat. Nos. 3,711,411 and 3,972,8.
No. 22, No. 40,088,590 and No. 4,371,448 essentially disclose at least one glycol compound and at least one glycol compound as a main component. Numerous brake fluids have already been described, consisting of corrosion inhibitors for the brake fluid as a basic component. These brake fluids
It meets the requirements more or less well in terms of boiling point, wet boiling point and viscosity at -40 ° C. Although such liquids have also shown corrosion protection for many metals / constituents, their corrosion behavior for metallic tin still has room for improvement. Also, the lack of this type of corrosion protection is problematic because brake fluid is often packaged and stored in tin plated containers. For this reason, it is desirable to use a brake fluid that is particularly effective against tin corrosion.

[0004]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to produce a brake fluid which not only has the above-mentioned usual properties, but is also well-corroded against ordinary metals and at the same time tin. is there. Accordingly, the new brake fluids correspond to types DOT3, DOT4 and DOT5 in terms of dry boiling point, wet boiling point and viscosity at -40 ° C., and must be made to have a very high corrosion protection, in particular with respect to metallic tin. Must.

[0005]

SUMMARY OF THE INVENTION The brake fluid according to the invention comprises essentially: A) at least one glycol compound as main component; B) at least one type of brake fluid for a brake fluid based on glycol compound. C) consisting essentially of mono- and diphosphates and obtained by reacting a phosphorus-containing compound with a monohydric alcohol and a polyol;
0.005 to 0.5% by weight (% by weight based on the weight of the brake fluid) of an acid phosphate mixture (as an additional inhibitor).

The present invention achieves an unexpectedly high corrosion inhibition effect, especially on metallic tin, by incorporating certain phosphoric ester products according to component C) into known brake fluids, which mainly consist of glycol compounds, and Are based on the surprising discovery that they are independent of the type of basic component compounds belonging to the group of glycols, their mono- and diesters, glycol formals, glycol borates and the like. It has been found that the addition of component C) results in a distinct and specific synergistic effect which may be due to the combination of component C) and the inhibitor already present in the liquid. Surprisingly, this combination not only achieves excellent corrosion protection, especially for metallic tin, but also meets the current requirements for common metals, such as cast iron and steel, copper, aluminum, zinc, etc. Has a preventive action. Brake fluids consisting mainly of glycol compounds together with different types of phosphates in combination with customary corrosion inhibitors, for example alkylamines, alkanolamines, alkali metal salts of inorganic or organic acids, triazoles, etc. (See the publications mentioned at the outset). Type D
Although these brake fluids of OT3, DOT4 and DOT5 have a relatively good corrosion protection effect on ordinary metals, they have room for improvement with respect to tin. Thus, it is surprising that in fact, a high anti-corrosion behavior, in particular on tin, is obtained with the phosphate ester products according to component C).

The component A) of the brake fluid according to the invention consists of one or more glycol compounds and forms the main component of the fluid. Glycol compounds that can be used include
Everything that normally forms the base of the brake fluid in question (see the publications mentioned at the outset).
Generally, such components are known glycol compounds selected from the group consisting of glycols, glycol monoalkyl ethers, glycol dialkyl ethers, glycol formals, glycol borates and glycol monoalkyl ether borates. . Preferably, the glycols are of the following formula 1

[0008]

Embedded image Wherein R ¹ is H or CH ₃ , and H and CH ₃ in the polyalkoxylene chain, which means that R ¹ has both the above meanings within the chain of the polyalkoxylene residue ), Preferably H, and x is 1-8, preferably 2-5). Examples of glycols are monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol and also polyoxyethylene glycols having a molecular weight of up to 400 and the corresponding propylene glycols and mixed alkoxylates, with ethylene glycol being preferred. .

Preferred glycol monoalkyl ethers are those of the following formula 2

[0010]

Embedded image Wherein R ² is H or CH ₃ , and H and CH ₃ within the polyalkoxylene chain, preferably H
Wherein R ³ is C ₁ -C ₄ -alkyl and y is 1 to 6, preferably 2 to 4). Examples of glycol monoalkyl ethers are
Diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monoethyl ether and the corresponding propylene glycols and mixed alkoxylate derivatives And ethylene glycol ethers.

Preferred glycol dialkyl ethers are those of the following formula 3

[0012]

Embedded image Where R ⁴ is H or CH ₃ , and H and CH ₃ within the polyalkoxylene chain, preferably H
R ⁵ is C ₁ -C ₄ -alkyl and R ⁶ is C ₁
-C ₄ - alkyl, and z is 1 to 6, is represented by preferably 2 to 4). Examples of glycol dialkyl ethers are diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol diisopropyl ether, triethylene glycol methyl isopropyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diisopropyl ether and tetraethylene glycol dibutyl ether and Corresponding propylene glycols and mixed alkoxylate derivatives are preferred, ethylene glycol ethers being preferred.

A preferred glycol formal is represented by the following formula 4 R ⁷ O— (CH ₂ CH ₂ O) _m —CH ₂ — (OCH ₂ CH ₂ ) _n —OR ⁸ (4) wherein R ⁷ is C ₁ -C ₄ - alkyl, R ⁸ is C ₁
ＣC ₄ -alkyl, m is 1 to 4 and n is 1 to 4). Particularly preferred bis (ethylene glycol monoalkyl ether) of formula 4
Formal is such that R ⁷ and R ⁸ are CH ₃ and m is 2 or 3 in each case, where m is equal to n.

Preferred glycol borates and glycol monoalkyl ether borates are represented by the following formulas 5 and 6 [R ⁹ O- (CH ₂ CH ₂ O) _a ] ₃ -B (5) wherein R ⁹ Is C ₁ -C ₄ -alkyl and a is 1 to 6, preferably 2 to 4)

[0015]

Embedded image Wherein R ¹⁰ and R ¹¹ are C ₁ -C ₄ -alkyl,
And b and c are each 1 to 6, preferably 1 to
4). Preferred borates of formulas 5 and 6 are those wherein R ⁹ is CH ₃ ;
And a is 2, 3 or 4; R ¹⁰ and R ¹¹
Is CH ₃ and b and c are each 2, 3, or 4.

The component B) of the brake fluid according to the invention consists of one or more compounds usually used as inhibitors in liquids consisting mainly of glycols and / or glycol derivatives (the publications mentioned at the outset). Please refer to). Generally, such components include alkylamines, cycloalkylamines, alkanolamines, monocarboxylic acids and alkali metal salts thereof, dicarboxylic acids and alkali metal salts thereof, alkali metal salts of carbonic acid, phosphoric acid and molybdic acid, triazole , Imidazoles, and known antioxidant aromatic compounds. Preferred alkylamines include 1 to 1 in each alkyl group.
Mono- having 8, preferably 3 to 8 carbon atoms,
Di- and trialkylamines such as butylamine, hexylamine, octylamine, isononylamine, isotridecylamine, oleylamine, diisopropylamine, dioctylamine, tributylamine,
Trihexylamine and dimethyloctylamine. Preferred cycloalkylamines are cyclohexylamine.

Preferred alkanolamines have the following formula 7

[0018]

Embedded image Wherein R ¹² is H or CH ₃ , d is 0, 1 or 2, preferably 0, and R ¹³ is H, C ₁ -C
₁₈ -preferably C ₁ -C ₈ -alkyl or of the formula

[0019]

Embedded image (Wherein R ¹² and d have the same meaning as above)
And R ¹⁴ is one of the meanings of R ¹³ ), for example, ethanolamine, methyldiethanolamine, isopropanolamine, diethanolamine, diisopropanolamine, butyldiethanolamine, octyldiethanolamine, Triethanolamine and triisopropanolamine.

Preferred monocarboxylic acids and their alkali metal salts are C ₅ -C ₁₈ -monocarboxylic acids (fatty acids) and their sodium salts, such as caprylic acid, lauric acid, stearic acid and oleic acid.

Preferred dicarboxylic acids and their alkali metal salts are those represented by HOOC- (CH ₂ ) _4-10 -COOH and its sodium salts, such as adipic acid, suberic acid, azelaic acid and sebacic acid.

Preferred alkali metal salts of carbonic acid, phosphoric acid and molybdic acid are sodium carbonate, sodium phosphate and sodium molybdate (Na ₂ MoO ₄ ).

Preferred triazoles and imidazoles are benzotriazole (also as 1H-benzotriazole and 1,2,3-benzotriazole),
Tolyltriazole (usually a mixture of isomers) and benzimidazole.

Preferred antioxidant aromatic compounds are phenols, bisphenols, cresols, quinolines and naphthylamines such as phenol, bisphenol A, 2,4-dimethyl-6-tert. -Butylphenol, styrene-modified phenol, 2,6-dimethyl-p-cresol, diphenylamine, phenyl-
It is selected from the group consisting of α-naphthylamine, styrenated diphenylamine, 4,4′-dioctyldiphenylamine and polymeric 2,2,4-trimethyl-1,2-dihydroquinoline.

Component B) generally comprises from 0.1 to 10% by weight,
Preferably it is present in an amount of from 0.5 to 8% by weight (% by weight is based on the weight of the brake fluid (pre-made)). Component B)
Usually comprises one or more of the above-mentioned inhibitors.
This preferably consists of one of the above-mentioned alkylamines or alkanolamines, or one of the above-mentioned alkylamines and alkanolamines and the above-mentioned triazole compounds,
Or alkanolamines represent the major amount, while triazoles are relatively minor. Thus, component B) contains 0.
5 to 8% by weight, preferably 0.5 to 6% by weight, (% by weight
Is based on the weight of the brake fluid).
5% by weight, preferably 0.05 to 0.3% by weight (% by weight
Is based on the weight of the brake fluid).

Component C) of the brake fluid according to the invention is a mixture of acidic phosphates. Thus, the above components consist essentially of phosphoric monoesters and phosphoric diesters. The phosphate triesters are present in very small amounts, if any. Yet another feature of the phosphate ester product is that polyols, as well as monohydric alcohols, are used for esterification with the starting phosphorus compound. To maintain the acidic properties of the phosphate ester product, the three reactants are used in a molar ratio such that essentially only primary and secondary phosphate esters are formed. The acid number of the phosphate mixture is generally between 300 and 700, preferably between 350 and 60.
0 (the acid value is determined in a known manner, for example by titration to the second inflection point of a titration curve using a NaOH solution, NaOH
Calculated by converting the consumption to mg KOH / g product).

An example of a suitable phosphorus compound is phosphoric acid (H ₃ P
O ₄ ), phosphorus trichloride (PCl ₃ ), phosphorus pentachloride (PCl ₅ )
And phosphorus pentoxide (P ₄ O ₁₀ ). Of the possible phosphorus compounds, phosphorus pentoxide is preferred because relatively time-consuming removal of water of reaction or HCl formed during esterification is avoided.

Preferred monohydric alcohols are those selected from the group consisting of alkanols and alkoxylated alkanols. Preferred monohydric alcohols are for use in, C ₁ -C ₁₂ - alkanols, preferably C ₁ ~
C ₆ -alkanols (linear or branched) or 1-1
These ethoxylates and propoxylates, preferably ethoxylates, having 5 alkoxylen units, preferably 1 to 8 alkoxylen units. Therefore, preferred monohydric alcohols are represented by the following formula 8

[0029]

Embedded image Wherein R ¹⁵ is H or CH ₃ , preferably H, and R ¹⁶ is preferably a linear alkyl residue having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms. And e is from 0 to 15, preferably from 0 to 8). Representative examples of monohydric alcohols include methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, n-amyl alcohol, isoamyl alcohol, n-hexanol, isononyl alcohol, n-decanol, lauryl alcohol and isotridecyl Alcohol and 1 to
These propoxylates, preferably ethoxylates, having 15 alkoxylen units, preferably 1 to 8 alkoxylen units.

Suitable polyols are alkanediols, alkanetriols, alkantetrols, pentitols and hesitols such as ethanediol (ethylene glycol), 1,2-propanediol, 1,3-propanediol. 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, pentanediol and hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol and pentaethylenediol and the corresponding propylene glycols, glycerol, Trimethylolpropane, trimethylolethane, erythritol and pentaerythritol, with diols and triols being preferred. Especially preferred polyols are (where, f is 2-8, preferably 2-5 (i.e., alkylene glycol)) The following formula _{9 HO- (CH 2) f -OH} (9) alkanediol or Equation 10 below

[0031]

Embedded image Wherein R ¹⁷ is H or CH ₃ , preferably H, and g is 1-10, preferably 1-5 (ie, alkoxylene glycol).

The component C) of the brake fluid according to the invention is preferably a phosphoric acid according to US Pat. No. 4,141,938 and EP 28,674, which are incorporated herein by reference. It is an ester product. Accordingly, a preferred acidic phosphate mixture is a mixture of phosphorus (V) oxide with a mixture of a monohydric alcohol and an alkane polyol having 2 to 12 carbon atoms and having 2 to 6 hydroxyl groups, preferably 1: 2: 4 / n 'molar ratio of phosphorus (V): monohydric alcohol: alkane polyol (where n' is the number of hydroxyl groups in the alkane polyol molecule) or stoichiometric excess alcohol While maintaining the active ingredients, the reactants are mixed or kneaded at a temperature of about 0 to 120 ° C., while removing water to remove the water from about 1 to 6 in the presence of an inert gas.
It is obtained by reacting for a time. Thus, in the case of monohydric alcohols and alkanediols, the molar ratio of phosphorus oxide (V): monohydric alcohol: alkanediol is 1: 2: 2, and in the case of alkanetrol as alkanepolyol, this is 1: 2. : 1. The reaction of the phosphorus (V) oxide with the monohydric alcohol and the alkane polyol is carried out in the exothermic phase of the reaction (by cooling the reaction mixture) at a temperature of from 0 to 70 ° C, preferably 20 to 60 ° C, and in the final phase of the reaction ( It has proven to be advantageous to work at a temperature of from 80 to 100 ° C. (by heating the reaction mixture). During this reaction, it is recommended to use an inert gas, for example, nitrogen gas. Generally, the reaction is completed in 1 to 3 hours, which is indicated by the absence of heat of the reaction formed in the initial exothermic reaction. After the reaction is complete and the reaction mixture has cooled, the desired mixture of acidic phosphates is present. As already mentioned, monohydric alcohols of formula 8 and alkanediols of formulas 9 and 10 represent preferred reactants for preparing component C) apart from phosphorus pentoxide.

As indicated in the above description, a feature of the brake fluid according to the invention is that its prevention system by components B) and C) is independent of that of component A). That is, the particular type of component A) is not critical to the effectiveness of the protection system. As is known, component A)
Determines the type of brake fluid, i.e., it is DOT3, DOT4 with respect to the properties that the brake fluid has at the beginning, i.e. in terms of dry boiling point, wet boiling point and viscosity.
And / or whether it belongs to the current normal type of DOT5 depends only on the component A). Thus, component B)
The effect of the protection system according to C) and C) is shown with all these types of brake fluid known per se. As regards the details of component A), as is known, two different formulations are preferred. In one formulation, component A) consists essentially of the glycol compounds described in the group consisting of glycols, glycol monoalkyl ethers and glycol dialkyl ethers, and these comprise the desired type of brake fluid. Used in such a ratio as can be obtained.
According to a second formulation, component A) consists essentially of glycol borates and glycol monoalkyl ether borates, glycol monoalkyl ethers,
It consists of the glycol compounds described in the group consisting of glycol dialkyl ethers, glycols and glycol formates, and again these are used in such a ratio that the desired type of brake fluid is obtained. Some representative compositions of component A) as described in the prior art section and in the class for brakes described above are listed below, provided that the individual components are A ₁ , A ₂ and A ₃ age,
And the percentages by weight stated are A ₁ ,
It is based on the total weight of A ₂ and A _3). Composition 1: A ₁ ) 30-80% of glycols of molecular weight up to 300 (the amount of glycols with a molecular weight of 150 or more is at least 20% by weight) and A ₂ ) 20-70% of glycol monoalkyl ether And / or glycol dialkyl ethers Composition 2: A ₁ ) 40-50% glycols of molecular weight up to 200 and A ₂ ) 50-60% glycol monoalkyl ethers Composition 3: A ₁ ) 50-70% up to 200 glycols of molecular weight and a ₂₎ 30-50% of glycol dialkyl ether composition 4: a ₁₎ glycols 30-50% of molecular weight 150 to 300 a ₂₎ 20 to 50% of the glycol monoalkyl ethers and a ₃ ) 10-20% glycol dialkyl ether composition 5: a ₁₎ 40 to 95 percent of glycidyl Lumpur acids and / or glycol borate ester and A ₂ monoalkyl ethers) 5% to 60% of the glycol monoalkyl ethers and / or glycol dialkyl ether composition 6: A ₁₎ 40 to 90 percent of the glycols and / or glycol borate esters of monoalkyl ethers a ₂₎ 5 to 50% of the glycol monoalkyl ethers and / or glycol dialkyl ethers and a ₃₎ 2-10% of the molecular weight 150 to 300 glycols composition 7: a ₁₎ 10~50 % Of borate esters of glycols and / or glycol monoalkyl ethers and A ₂ ) 50 to 90% of glycol monoalkyl ethers Composition 8: A ₁ ) 10 to 20% of borate esters of glycol monoalkyl ethers A ₂ ) 40-60% Glycol monoalkyl ethers and A ₃₎ 15 to 45% of the molecular weight 150 to 300 glycols Composition 9: A ₁₎ 20 to 40% of the glycols and glycol monoalkyl ethers borate ester A ₂₎ 30 to 60 percent production of glycol monoalkyl ethers and a ₃₎ 10 to 40% of bis (ethylene glycol monoalkyl ether) brake fluid according formals present invention is carried out by mixing in a vessel containing the ingredients for example stirrer, as a result A homogeneous mixture is obtained in a simple manner. In general, the mixing takes place at normal pressure and at room temperature, it being advantageous to keep the water away. The mixing is performed at a high temperature, for example, 30 to
It can also be performed at 50 ° C.

The brake fluid according to the invention is particularly suitable for hydraulic brake systems, preferably for motor vehicles.

[0035]

The present invention will be described in more detail with reference to Examples and Comparative Examples.

The percentages given in the examples and comparative examples are based on weight, and the individual brake fluids were prepared by mixing the listed components at room temperature. The brake fluids from the examples and comparative examples were tested for boiling point (dry boiling point), wet boiling point, viscosity at -40 ° C and tin corrosion. Boiling point, wet boiling point and -4
The viscosity at 0 ° C. was determined by FMVSS No. 116 was followed exactly. Tin corrosion was similarly determined for FMVSS Nos. 1
16, but in addition a more severe test configuration was carried out without the addition of 5% by volume of water to the brake fluid sample (this is part of the test), and therefore the brake fluid was Used as is as in the case of As we know,
Water up to 5% by volume often reaches only after several years of use of the brake fluid.

Example 1 A) 42.00% triethylene glycol 22.10% diethylene glycol monomethyl ether 35.00% triethylene glycol mono-n-butyl ether B) 0.80% diisopropanolamine 0.05 % Toluyltriazole C) 0.05% of an acidic phosphate mixture prepared as follows Boiling point 235 ° C. Wet boiling point 147 ° C. Viscosity 1284 mm ² / s Tin corrosion ± 0 mg / cm ² Preparation of acidic phosphate mixture: 33 0.3 g (0.45 mol) of n-butanol and 2
7.9 g (0.45 mol) of ethylene glycol were mixed in a 250 ml glass vessel equipped with a stirrer under a nitrogen gas atmosphere. 63.9 g (0.225 mol) of P ₄
O ₁₀ over 30 minutes with stirring charged to the mixture, the mixture was cooled with an water / ice mixture at that time. During the addition, the temperature of the reaction mixture rose from 22 to 55 ° C. After the exothermic reaction subsides, the reaction mixture is
Heat to 80 ° C within hours and hold at 80-85 ° C for 1 hour. After cooling, 125 having an acid number to the second inflection point of 564 mg KOH / g and a pH of 9.5.
g of a colorless viscous liquid was obtained.

Example 2 A) 42.07% triethylene glycol 6.60% triethylene glycol monomethyl ether 35.00% triethylene glycol mono-n-butyl ether 15.00% triethylene glycol dimethyl ether B) 1.10% tributylamine 0.20% benzotriazole C) 0.03% acidic phosphate mixture according to example 1 Boiling point 257 ° C. Wet boiling point 146 ° C. Viscosity 1090 mm ² / s Tin corrosion -0.01 mg / cm ² example 3 a) 34.59% of the triethylene glycol monomethyl ether 61.40% of the formula _{[CH 3 O- (CH 2 CH 2} O) 3 ] ₃ borate ester B) 3.90% of the butyl diethanolamine B 0 .10% benzotriazole C) according to example 1 0.01% Sex phosphate ester mixture having a boiling point 282 ° C. wet boiling point 187 ° C. The viscosity 1264mm ² / s Tin corrosion -0.01 mg / cm ² Example 4 A) 61.40 percent tetraethylene glycol monomethyl ether 35.50% of the formula

[0039]

Embedded image B) 3.00% diisopropanolamine 0.05% tolyltriazole C) 0.05% acidic phosphate mixture according to Example 1 Boiling point 270 ° C. Wet boiling point 174 ° C. Viscosity 1768 mm ² / s Tin corrosion ± 0 mg / cm ² Example 5 A) 35.30% tetraethylene glycol monomethyl ether 61.40% borate ester as in Example 3 B) 3.20% diisopropanolamine 0.05% toluyltriazole C ) 0.05% of an acidic phosphate mixture prepared as follows Boiling point 284 ° C. Wet boiling point 186 ° C. Viscosity 1250 mm ² / s Tin corrosion ± 0 mg / cm ² Preparation of acidic phosphate mixture: 75 g (0.5 mol) ) Of triethylene glycol and 30 g (0.5 mol) of isopropanol The mixture was mixed in a 250 ml glass container equipped with a stirrer under a raw gas atmosphere. 71 g (0.25 mol) of P ₄ O ₁₀ were added to the mixture with stirring over 30 minutes, at which time the mixture was cooled with a water / ice mixture. During the addition, the temperature of the reaction mixture rose from 22 to 60 ° C. The reaction mixture was then kept at 80 ° C. for 2 hours. The product, cooled to room temperature, was a slightly brownish viscous liquid. The second point of inflection of this product
Acid value up to 482 mg KOH / g.

Example 6 A) 59.00% tetraethylene glycol monomethyl ether 35.50% borate ester as in Example 4 B) 5.40% octyldiethanolamine 0.10% benzotriazole C) 0 0.03% of an acid phosphate mixture prepared as follows Boiling point 270 ° C. Wet boiling point 173 ° C. Viscosity 1760 mm ² / s Tin corrosion ± 0 mg / cm ² Preparation of acid phosphate mixture: 38 g (0.5 mol) 71 g of 1,3-propanoldiamine and 23 g (0.5 mol) of ethanol
(5) The method of Example 5 was repeated except that it was reacted with (0.25 mol) of P ₄ O ₁₀ . A slightly brownish viscous liquid having an acid number up to the second inflection point of 589 mg KOH / g was obtained.

Example 7 A) 17.99% triethylene glycol monomethyl ether 5.00% tetraethylene glycol dimethyl ether 74.80% Boric ester similar to Example 3 B) 2.10% diisopropanolamine 0.10% toluyltriazole C) 0.01% acidic phosphate mixture according to example 1 Boiling point 275 ° C. Wet boiling point 195 ° C. Viscosity 880 mm ² / s Tin corrosion ± 0 mg / cm ² Comparative examples 1 to 7 Examples 1 to 7 were repeated without using [the brake fluid mixture was captured with the first representative from component A) to 100% by weight].

These brake fluids exhibited substantially the same values as the brake fluid according to the invention in terms of boiling point, wet boiling point and viscosity at -40 ° C., but were very poor with regard to tin corrosion. That is, the tin corrosion value is -0.12-
It was in the range of -0.16mg / cm ^2.

Comparative Example 8 A) 35.30% tetraethylene glycol monomethyl ether 61.40% borate ester similar to Example 3 B) 3.20% diisopropanolamine 0.05% tolyltriazole C) 0.05% of an acidic phosphate mixture prepared as follows Boiling point 285 ° C. Wet boiling point 185 ° C. Viscosity 1285 mm ² / s Tin corrosion -0.10 g / cm ² Preparation of acidic phosphate mixture: 90 g (1. (5 mol) of isopropanolamine was immediately introduced into a 250 ml glass vessel equipped with a stirrer under a nitrogen atmosphere. Then 71 g (0.25 mol) of P
₄ O ₁₀ is added in small portions with stirring, the mixture being cooled with a water / ice mixture to form
It was kept at 40 ° C. The reaction mixture was then kept at 80 ° C. for 1 hour. A clear, colorless, viscous liquid having an acid number up to the 2 n inflection point of 490 mg of KOH / g was obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C10M 107: 52 133: 08 133: 12 137: 04 129: 12) C10N 30:12 40:08 (58) Field surveyed (Int .Cl. ⁶ , DB name) C10M 169/04 C10M 105/14 C10M 105/78 C10M 107/34-107/52 C10M 133/08-133/12 C10M 137/04 C10M 129/12 C10N 30:12 C10N 40 : 08 EPAT (QUESTEL) WPI / L (QUESTEL)

Claims (9)

(57) [Claims] 1. Essentially, A) at least one glycol compound as a main component, B) at least one inhibitor for brake fluids based on a glycol compound, and C) essentially monophosphate esters And diphosphoric esters, and obtained by reacting a phosphorus-containing compound with a monohydric alcohol and a polyol,
0.005 to 0.5% by weight (% by weight based on the weight of the brake fluid) of an acid phosphate mixture,
Brake fluid that prevents metal corrosion. 2. The amount of component C) is from 0.01 to 0.1% by weight.
The brake fluid according to claim 1, which is: 3. A method according to claim 1, wherein component C) is a mixture of phosphorus (V) oxide with a monohydric alcohol and an alkane polyol having 2 to 12 carbon atoms and having 2 to 6 hydroxyl groups. 2: 4 / n 'phosphorus oxide (V): monohydric alcohol: alkane polyol molar ratio (where n' is the number of hydroxyl groups in the alkane polyol molecule) or stoichiometric excess alcoholic component While mixing or kneading the reactants at a temperature of about 0 to 120 ° C. while removing water while reacting in the presence of an inert gas for about 1 to 6 hours while maintaining 3. The brake fluid according to claim 1, which is a mixture. 4. The composition of claim 1, wherein component C) is phosphorus (V) oxide and has the formula 8 (Wherein, R ¹⁵ is H or CH ₃ , and R ¹⁶ is 1-12
A monohydric alcohol having the following formula 9 HO— (CH ₂ ) _f —OH (9) wherein f is 2 to 8) or of the following formula 10: Wherein R ¹⁷ is H or CH ₃ , and g is 1 to
10) and a molar ratio of phosphorus oxide (V): monohydric alcohol: alkane polyol of 1: 2: 4 / n ′ (where n ′ is a hydroxyl group in the alkane polyol molecule). Is the number of
Alternatively, while maintaining the stoichiometric excess of alcoholic components, mixing or kneading the reactants at a temperature of about 0 to 120 ° C., and removing about 1 to 6 The brake fluid according to claim 1 or 2, which is a mixture of acidic phosphates obtained by reacting for hours. 5. Component A) is a glycol compound selected from the group consisting of glycols, glycol monoalkyl ethers, glycol dialkyl ethers, glycol formals, glycol borates and glycol monoalkyl ether borates. And component B) is an alkylamine, a cycloalkylamine, an alkanolamine, a monocarboxylic acid and its alkali metal salt, a dicarboxylic acid and its alkali metal salt, an alkali metal salt of carbonic acid, phosphoric acid and molybdic acid, a triazole, and an imidazole. The brake fluid according to any one of claims 1 to 4, which is an inhibitor selected from the group consisting of antioxidants and antioxidant aromatic compounds. 6. Component A) has the following formula 1 Where R ¹ is H or CH ₃ , and H and CH ₃ in the polyalkoxylene chain, and x is 1
To 8), which is represented by the following formula 2: (Wherein, R ² is H or CH _3, and is H and CH ₃ in a polyalkoxylene chain, R ³ is C ₁ ~
C ₄ -alkyl and y is 1 to 6) glycol monoalkyl ethers of formula 3 Wherein R ⁴ is H or CH ₃ , and H and CH ₃ in the polyalkoxylene chain, and R ⁵ is C _1-
Glycol dialkyl ethers of C ₄ -alkyl, R ⁶ is C ₁ -C ₄ -alkyl and z is 1-6), of the formula 4 R ⁷ O— (CH ₂ CH ₂ O) _{m -CH 2 - (OCH 2 CH} 2) n -OR 8 (4) ( wherein, R ⁷ is C ₁ -C ₄ - alkyl, R ⁸ is C ₁
-C ₄ - alkyl, m is 1-4 and n is glycol formals of 1 to 4), the following formula 5 _{^{[R 9 O- (CH 2 CH 2}} O) a ] ₃ - Glycol borate esters of B (5) wherein R ⁹ is C ₁ -C ₄ -alkyl and a is 1 to 6; Wherein R ¹⁰ is C ₁ -C ₄ -alkyl and R ¹¹ is C ₁
-C ₄ - alkyl and b is 1-6, and c is a glycol compound selected from the group consisting of glycol monoalkyl ether boric esters of 1 to 6), and component B) Is 1 in each alkyl group
Mono-, di- and trialkylamines having up to 18 carbon atoms, of the following formula 7 Wherein R ¹² is H or CH ₃ , d is 0, 1 or 2, and R ¹³ is H, C ₁ -C ₁₈ -alkyl or a compound of the following formula: (Wherein R ¹² and d have the same meaning as above)
And R ¹⁴ is one of the meanings of R ¹³ ], alkanolamines, C _5-to C ₁₈ -monocarboxylic acids and alkali metal salts thereof, of the formula HOOC-
(CH ₂ ) _k —COOH) (where k is 4 to 10) dicarboxylic acids, alkali metal salts of carbonic acid, phosphoric acid and molybdic acid, triazoles, imidazoles, and phenols, bisphenols, cresols The brake fluid according to any one of claims 1 to 4, wherein the brake fluid is an inhibitor selected from the group consisting of antioxidant aromatic compounds selected from the group consisting of quinolines and naphthylamines. 7. Component B) is 1-18 in each alkyl
Mono-, di- and trialkylamines having two carbon atoms, of the following formula 7 Wherein R ¹² is H or CH ₃ , d is 0, 1 or 2, and R ¹³ is H, C ₁ -C ₁₈ -alkyl or a compound of the following formula: (Wherein R ¹² and d have the same meaning as above)
And R ¹⁴ is one of the meanings of R ¹³ ], which is an inhibitor selected from the group consisting of alkanolamines and triazoles. The brake fluid according to the above. 8. Component (B) is present in an amount of 0.1 to 10% by weight (% by weight
The brake fluid is based on the weight of the brake fluid). 9. Mono-, di-monomers having component B) having from 1 to 18 carbon atoms in each alkyl group in an amount of from 0.5 to 8% by weight (% by weight based on the weight of the brake fluid). And trialkylamines of the following formula 7 Wherein R ¹² is H or CH ₃ , d is 0, 1 or 2, and R ¹³ is H, C ₁ -C ₁₈ -alkyl or a compound of the following formula: (Wherein R ¹² and d have the same meaning as above)
And R ¹⁴ is one of the meanings of R ¹³ ] and alkanolamines of 0.01 to 0.5
9. A brake fluid according to any one of the preceding claims, which is an inhibitor selected from the group consisting of triazoles in an amount by weight (weight% is based on the weight of the brake fluid).