JPS5923758A - Method of usably circulating brake liquid - Google Patents

Abstract

PURPOSE:To restrain the drop of boiling point of brake liquid by making polyalkylene-glycol system brake liquid contact a drive molecular sieve to absorb moisture from the brake liquid. CONSTITUTION:A dried molecular sieve is received in a perforated bag disposed in a filter chamber for brake liquid. And when polyalkyleneglycol system brake liquid is circulated usably, the brake liquid contacts the molecular sieve so that moisture is absorbed. Thus, the drop of boiling point of the brake liquid is restrained.

Description

[Detailed description of the invention] The present invention relates to a method for circulating brake fluid.

Brake fluid used in the brake circuits of vehicle machinery such as automobiles is the only fluid that reliably transmits pedal force to the braking mechanism of each wheel.
Since it directly affects human life, its quality and standards must be the most reliable.

In particular, recently, brake fluids are required to have a high boiling point, especially when they contain water, in order to prevent paper locks that occur when driving at high speeds or using the brakes frequently on long downhill slopes. .

The current mainstream brake fluid is a liquid composition that is a blend of polyglycols, glycols, and glycol ethers (hereinafter abbreviated as polyalkylene glycol oil or polyalkylene glycol type).
This has the disadvantage that it tends to absorb moisture during use, resulting in a drop in boiling point, which causes paper lock. Therefore, those with a low boiling point when containing water are not preferred;
The J■S standard (K
According to 2233), the wet boiling points of brake fluids of JIS Type 3 and Type 4 standards are 140°C and 15°C, respectively.
It is stipulated that the temperature must be 5°C or higher.

The higher the boiling point of the brake fluid in relation to Paper Rock, especially the boiling point when it absorbs moisture, the better.Dimethyl 7-licon and other new types of brake fluid are being developed to meet these needs, but polyalkylene The reality is that the price is significantly higher than that of glycol-based products, which hinders their widespread use.

As mentioned above, polyalkylene glycol-based brake fluid absorbs several percent of moisture per year due to direct or indirect contact with the outside air during use, making it susceptible to paper lock. This problem cannot be avoided except by replacing the liquid with a new one, and there has been no known method to easily and appropriately solve this problem without replacing the liquid with a new one. Therefore, the development of a simple solution to this problem would be extremely beneficial in conjunction with the recent trend in Japan of extending vehicle inspection periods.

It is well known that the main cause of moisture absorption in brake fluid during use is penetration of moisture in the outside air, rainwater, car wash water, etc. through SBR brake ports, and in weather conditions like those in Japan. , after 6 months it reaches around 15% (by weight), after 1 year it reaches around 6% (by weight), after 2 years it reaches 4-5% (by weight), and in special environments it can reach around 7% (by weight) The theme has been announced. However, moisture absorption of the brake fluid during use is unavoidable as long as the current type of flexible full brake hose is used, and the resulting drop in the boiling point of the brake fluid and paper locks are at risk for human life. This is considered as the biggest issue in this field.

An object of the present invention is to provide a method for circulating brake fluid that can suppress a drop in the boiling point of polyalkylene glycol brake fluid filled in a new car due to moisture absorption and extend the life of the fluid.

Another object of the present invention is to provide a simple method for circulating brake fluid that can improve the boiling point of polyalkylene glycol brake fluid that has already absorbed moisture.

As a result of intensive research into a method that can satisfy these objectives, the inventor of the present application has developed a "molecular sieve" system in which the circulating brake fluid is stored in a porous bag when the polyalkylene glycol brake fluid is used for circulation. '' (trade name) (hereinafter abbreviated as M and S), we have discovered that the above objectives can be achieved by adopting a method in which this bag is present in the brake fluid filter chamber, and we have published this book. This led to the completion of the invention.

The polyalkylene glycol flake liquid used in the present invention mainly consists of a base polymer component that accounts for about 5% to about 20% (by weight) and about 60% to about 80% (by weight). It consists of a solvent component that accounts for

Examples of base polymers include propylene oxide base polymers such as polyoxypropylene glycol and polyoxypropylene triol, poly(oxyethylene/oxypropylene) glycol monoalkyl ether, and poly(oxyethylene/oxypropylene) triol. Examples include ethylene oxide/propylene oxide base polymers represented by ethylene oxide/propylene oxide base polymers and ethylene oxide base polymers represented by polyoxine ethylene glycol.

The solvents mentioned here are diethylene glycol monomethyl ether (MD()), diethylene glycol monomethyl ether (MTG), and t! J ethylene glycol monoethyl ether (ETG), diethylene glycol monobutyl ether (BDG), )! Ethylene oxide solvents represented by ethylene glycol monophthyl ether (BTG) and polyethylene glycol monoalkyl ether, propylene oxide solvents represented by dipropylene glycol monomethyl ether and polypropylene glycol monoalkyl ether, and poly(oxyethylene Examples include ethylene oxide and propylene oxide solvents represented by glycol monoalkyl ether (oxypropylene).

In the polyfulkylene glycol brake fluid referred to herein, at least one of the above-mentioned hese polymer components and solvent components and boron compounds (anhydrous boric acid, orthoboric acid, and metaboric acid) having the ability to form boric acid esters are added under reduced pressure. The polyalkylene glycol brake fluid may contain boric acid esters that can be synthesized by heating (for example, 50 to 200°C). To maintain the physical properties of brake fluid over a long period of time,
Various known additives having the purpose of replenishing the physical properties lacking in the solvent and haze polymer may be blended as necessary.

Furthermore, IVI, S as used in the present invention is a crystalline synthetic theolite developed by Union Carbide Company (UCC), and various brands are commercially available for different uses depending on the pore size. ing. For the purpose of selectively adsorbing water in a liquid consisting of an organic component as in the present invention, any of M and S commercially available as 6A, 4A, 5A and 16-x types can be effectively used. However, among them, 6A and 4A are preferable, and 4A is especially preferable.
Types are most preferred. Also, M such as Norton's Zeoron (trade name),
S, Aimura products can also be used.

These commercially available M, S, are usually 350″ prior to use.
Although it is necessary to perform a heat treatment to a higher degree than C and dry it, in the present invention, the already dried M and S are stored and sealed in a porous bag, so there is no need for complications before use. It does not require any heat treatment and can be used as is.

In addition, the porous bag in the present invention is a bag made from a material selected from woven fabric, nonwoven fabric, film, porous semipermeable membrane, and other categories having a large number of pores. Made of materials that are not attacked by alkylene glycol brake fluids. Among these, the most preferred porous material for achieving the purpose of the present invention is a microporous plastic semipermeable membrane that has been developed for battery separators and other uses in recent years. One of the difficulties when trying to apply the selective dehydration ability of M,S to the water-containing brake fluid circulating in the brake circuit is the mechanical strength of the M,S pellets. exists in

That is, M, S, and pellets have low impact resistance due to their synthetic characteristics, and they tend to fracture and become fine particles even with a relatively small impact. Therefore, it is impossible to carry out the method of the present invention by simply using pellet-shaped M and S, which are normally available on the market, as they are for the circulating brake fluid. Particularly in the embodiment of the present invention, even if M and S are improperly handled, the object of the present invention must still be achieved smoothly and safely. Porous materials have made it possible to implement the present invention by eliminating these inherent drawbacks, and among them, microporous plastic semipermeable membranes are the most excellent material in terms of performance. I was able to find out this time.

Another preferable porous material in consideration of economic efficiency is a nonwoven fabric made by tearing a polyethylene or polypropylene stretched film and adhering or thermocompressing two webs at right angles in the length and width. This material is commercially available from Nippon Petrochemicals Co., Ltd. as "Shiraishi Warif" (trade name). The porous material made by backing a Japanese paper-like fibrous nonwoven fabric with "Shiraishi Warifu" to give it strength is M and S of the present invention.
.

It was also found that it is suitable as a material for making storage bags.

Next, a method for manufacturing the M, S, storage porous bag used in the present invention will be described. Since M, S, has a moisture absorbing ability second only to phosphorus pentoxide, it is necessary to handle it carefully.

As the first step, approximately 6 m
Bags with a surface area of ×6 cm are made.

Any method may be used for making the bag, but adhesion method 1 using ethylene/vinyl acetate copolymer or others, thermocompression bonding method, and others can be advantageously used.

In the thus obtained porous bag, heat-dried M, S,
Approximately 18y of pellets can be stored. The nuclear bag containing M and S is sealed by any means.

Then, in the second step, M produced in the first step,
S. Wrap the stored porous bag with a moisture-proof film. Aluminum foil laminated with polyethylene or ethylene/vinyl acetate copolymer and others are suitable as the moisture-proof film. Normally, M and S products often absorb moisture due to non-linking, unless they are shipped in special packaging for large-scale consumption.

The second step is an essential step for eliminating this essential drawback of M and S and allowing even those skilled in the art to easily achieve the object of the present invention.

Next, how to use the bag will be described in detail. This M, S
, is removed from the moisture-proof packaging before use, and placed in one of the two brake fluid containers of the brake master cylinder under the bonnet of the car that does not contain the fluid gauge. Just put it in the filter chamber inside. Thereafter, the brake fluid circulating in the brake fluid circuit automatically comes into contact with F-M, S, thereby effectively achieving the object of the present invention.

The benefits of implementing the method of the present invention are listed below.

(a) It is possible to improve the boiling point of brake fluid that has already absorbed moisture without replacing some or all of the brake fluid.

(o) By simply placing the porous bag containing M and S into the filter chamber of the brake fluid filled in a new car, the drop in the boiling point of the brake fluid can be suppressed and the life of the fluid can be extended.

9. The implementation method is simple and inexpensive, and can be performed without a person skilled in the art.

2) It is possible to rehabilitate the brake fluid that has absorbed moisture without having to extract it from the circuit.

Next, examples will be described to further specifically explain the present invention.

Example 1 Preparation of basic brake fluid for testing Polyalkylene brake fluids having the basic formulation shown in the following table were subjected to testing. The boiling point of this brake fluid is 250'
C, and fully satisfied the 6th grade standard 1205° C. or higher described in the Ji8 standard (K 2233). In addition, the brake fluid prepared with this formulation, which contains various known additives, has a specific gravity of 1.030 (15/4°C) and has passed all of the 6 types of standards of the JIS standard (K 2233). .

Test brake fluid formulation Adeka Carpol MBFloo 40 Adeka Carpol GL250 5 Adeka Carpol GH200 1,0 Methyl Triglycol (MTG
) 40 triethylene glycol (TgG)
500
), 4.6 (50°C), and 76-0 (-40°C).

Next, 300 cc of the test basic brake fluid, which had been forcibly hydrated with 6% (by weight) water, was collected in a glass container, and 4A
A porous bag (manufactured by Nisseki Warif) containing molds M and S for 18 years was introduced into the solution, and the solution was allowed to stand for 5 days at room temperature with occasional shaking, and then its boiling point ('G) was measured. M,
8. The relationship between the amount used and the boiling point was as shown in Figure 1.

Examples 2-4 A test base brake fluid with the same formulation as used in Example 1 was used as the test stock solution. Next, 300 cc of each of three types of water-containing samples were collected in containers by forcing this stock solution to contain 1% (by weight), 6% (by weight), and 5% (by weight) of water. One of the stored porous bags was put into each container and left to stand for 3 days with occasional shaking, and then the equilibrium reflux boiling point of each lot was measured.

The results are shown by O in FIG. The curve shown by the solid line shows the relationship between the water content and boiling point of an untreated water-containing sample that is not treated with M or S. The amounts of M and S used in the sample were equivalent to 6% (by weight).

As is clear from the results in Figure 1, when the target was the 3 (weight) official water brake fluid, which is considered to be the most common force based on the national vehicle inspection period.

By circulating the brake fluid in the presence of 7% (by weight) or less of M and S, a remarkable effect of improving the boiling point is observed.

The results shown in Fig. 2 show that the method of the present invention is effective in any case within the practical moisture absorption range of 1 to 6 (weight), and also shows that the method of the present invention is effective in any case in the practical moisture absorption range of 1 to 6 (weight). This indicates that a longer life can be achieved by suppressing the drop in boiling point.

In addition, the quality of brake fluid deteriorates due to M, S, processing,
For example, no decrease in dry boiling point, metal corrosion, or rubber swelling was observed.

[Brief explanation of the drawing]

FIG. 1 to FIG. 2 are diagrams showing the effects of the present invention. Patent Applicant: Ethylene Chemical Co., Ltd. Procedural Amendment dated September 1980, Commissioner of the Patent Office, 1, Indication of Small A'1, 1982, Patent Application No. 134191, 2, Title of Invention: Method for Circulating Use of Brake Fluid 3 , Relationship with the person making the amendment 1. Name of person 1. Chiren Chemical Co., Ltd. 4. Agent 5. Date of amendment order (Voluntary) (Delivery 1) 1939, Month, Day 7, Contents of amendment (1) Page 7 of the specification, lines 13-14, “Collaborative Zeolite” is amended to “Synthetic Zeolite J.”

Claims (3)

[Claims] (1) A method characterized in that, when a brake fluid containing polyalkylene glycol oil as a main component is circulated, the circulating brake fluid is brought into contact with a dried molecular sieve. (2) Claim 1, characterized in that the molecular sieve is present in the brake fluid filter chamber.
The method described in section. (3) The method according to claim 1 or 2, wherein the molecular 7-b is used by storing it in a porous bag.