JP2000336342A - Friction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive friction material suitable as a brake lining, a clutch material, etc., for automobiles and excellent in coefficient of friction and fade and abrasion resistances. SOLUTION: This friction material comprises a substrate, a binder and a filler and is obtained by compounding a particulate aluminum borate having 1-10 μm median average particle diameter and <=2 aspect ratio as the substrate of the friction material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction material having improved physical properties such as a coefficient of friction, fade resistance and abrasion resistance, and more particularly to a friction material suitable for a brake lining and a clutch material for an automobile. .

[0002]

2. Description of the Related Art Automotive brake linings, clutch fadings, disc pads, etc. are made of a base material, a friction modifier, a filler, and a binder such as phenol resin.
Conventionally, asbestos has been frequently used as a base material. In recent years, the use of asbestos-free friction material has been promoted in order to prevent environmental pollution by asbestos and to improve the working environment.
Ceramic fibers such as alumina / silica fiber, rock wool, potassium titanate fiber, and calcium carbonate fiber are known as a base material to replace asbestos (for example, Japanese Patent Application Laid-Open No.
142386, JP-A-6-207164,
JP-A-9-316209, JP-A-3-18503
No. 2, JP-A-3-166287, etc.).

[0003] Characteristics required for a friction material such as a brake lining include a friction coefficient, fade resistance, and wear resistance. Among the ceramic fibers, alumina / silica fibers are excellent in friction coefficient and wear resistance, but due to high hardness, the mating material is severely worn and poor in fade resistance. On the other hand, potassium titanate fibers and calcium carbonate fibers had low hardness, and thus had poor wear resistance.

In order to solve such a problem, a friction material using a fibrous aluminum borate having excellent friction coefficient and abrasion resistance as a ceramic fiber is known (for example, Japanese Patent Application Laid-Open No. 10-17855). .

However, fibrous aluminum borate is an expensive ceramic fiber, and a friction material containing a large amount of fibrous aluminum borate has a high manufacturing cost and is difficult to be put to practical use.

[0006]

SUMMARY OF THE INVENTION The present invention solves these problems in the prior art and is inexpensive and has a low coefficient of friction.
An object of the present invention is to provide a friction material excellent in fade resistance and wear resistance.

[0007]

The present inventors have conducted intensive studies in view of such circumstances, and as a result, as a substrate, a particulate aluminum borate having a center particle diameter of 1 to 10 μm and an aspect ratio of 2 or less. By using, a friction material which is inexpensive and has excellent friction coefficient, fade resistance and wear resistance has been found, and the present invention has been completed.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The particulate aluminum borate used in the practice of the present invention is obtained by mixing an aluminum oxide supply component and a boron oxide supply component at 800 to 1300 ° C.
After heating and reacting at a temperature of, the particles having a central particle diameter of 1 to 10 μm and an aspect ratio of 2 or less are purified by using water, an aqueous acidic solution or an aqueous alkaline solution as necessary, and dried and pulverized. It was prepared into a shape.

[0009] In the practice of this invention, the particulate aluminum borate are preferred those having a composition represented by _{9Al 2 O 3 · 2B 2 O} 3 or _{2Al 2 O 3 · B 2 O} 3, In order to enhance the compatibility and adhesion of the particulate aluminum borate to the binder, the surface thereof may be subjected to a surface treatment with various coupling agents, organic polymers, or the like.

In the practice of the present invention, it is possible to use particulate aluminum borate alone as a base material. However, alumina fiber, rock wool, potassium titanate fiber, calcium carbonate fiber may be added to the particulate aluminum borate. It is also possible to use one or more kinds of fibers selected from ceramic fibers such as aluminum borate fibers or metal fibers such as steel fibers in combination.

Further, the friction material of the present invention may be blended with friction modifiers and fillers such as barium sulfate, molybdenum disulfide, graphite, various fillers, metal powders and the like as long as the performance is not deteriorated.

[0012]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The raw materials used for the substrates in the examples and comparative examples are as follows. Particulate aluminum borate [manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name “Arbolite PF03”, chemical formula 9Al ₂ O ₃ .2B ₂ O ₃ , center particle size 3 μm], particulate aluminum borate [manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name “ arbovirus light PC08 ", chemical formula _{9Al 2 O 3 · 2B 2 O} 3,
Center particle diameter 8 μm], potassium titanate fiber [manufactured by Otsuka Chemical Co., trade name “TISMO-D”, fiber diameter 0.1 to 0.5 μm,
Fiber length 10-30 μm], calcium carbonate fiber [Maruo calcium, trade name “Whistal A”, fiber diameter 0.1-0.5μ]
m, fiber length 20 to 30 μm], alumina / silica fiber [manufactured by Toshiba Monoflux, trade name “RFC400-SL”, fiber diameter 2 to 4 μm, fiber length 300 to 500 μm], aluminum borate fiber [manufactured by Shikoku Chemical Industry, Trade name “Albolex M20”, fiber diameter 0.5 to 1.0 μm, fiber length 10 to 30 μm] Note that the particulate aluminum borate used in Example 1 and Example 2 was “Albolite PF0”
3 "and" Arbolite PC08 ".

[Examples 1 and 2 and Comparative Examples 1 to 4] The binders, base materials and fillers shown in Table 1 were uniformly mixed with a planetary mixer. Press molding was performed for 20 seconds using a molding machine adjusted to a pressure of 120 kg / cm ² to obtain a preform. Mold temperature 170 ℃,
A friction material was manufactured by heating and pressurizing for 20 minutes using a molding machine adjusted to a surface pressure of 350 kg / cm ² , then heat-treating in a heating furnace at a furnace temperature of 200 ° C for 8 hours, and then polishing.

The friction coefficient, wear amount and fade resistance of the obtained friction material were measured or observed. Table 1 shows the test results. The friction coefficient is an average friction coefficient obtained from a bench general efficacy test based on JASO (Japanese Automobile Standard) C-406, and the wear amount is JASO C-42.
According to 7-83, brake 10 in the temperature range of 100 ° C.
It represents the amount of pad wear equivalent to 00 times. The pad was made of the friction material, and the disk was made of FC250.

[0015]

[Table 1]

According to the test results in Table 1, the friction material using particulate aluminum borate as the base material has a coefficient of friction,
It was excellent in all aspects of wear amount, fade resistance and material cost.

The friction material using the potassium titanate fiber or the calcium carbonate fiber in Comparative Examples 1 and 2 is as follows:
The coefficient of friction was small and the amount of wear was large. Also,
The friction material using the alumina / silica fiber in Comparative Example 3 is expensive and inferior in fade resistance. The friction material using the aluminum borate fiber of Comparative Example 4 is the same as in Examples 1 and 2. In addition, the friction coefficient, the wear amount, and the fade resistance are excellent, but the material cost is high.

[0018]

According to the present invention, a friction material excellent in friction coefficient, fade resistance and abrasion resistance and extremely inexpensive can be provided.

Continued on the front page F term (reference) 3J058 BA34 BA41 BA61 BA76 FA01 GA22 GA81 GA82 GA92 GA93 4J002 CC001 CC031 DA028 DA068 DC007 DE147 DE187 DE237 DG028 DG048 DK006 DK007 FA047 FD010 FD017 FD208 GM00 GN00

Claims (2)

[Claims] 1. A friction material comprising a base material, a binder and a filler, wherein a particulate aluminum borate is blended as the base material. 2. The method according to claim 1, wherein the particulate aluminum borate is 9Al ₂ O.
₃ · _2B 2 _{O 3} or _2Al having a composition represented by _{2 O 3 · B 2 O 3} , wherein the center particle size of the particulate aluminum borate is 1 to 10 [mu] m, an aspect ratio of 2 or less The friction material according to claim 1.