JP3219151B2 - Heat resistant dry friction material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-asbestos-based heat-resistant dry-type friction material used as a brake pad, a brake lining, a clutch facing of a vehicle, an industrial machine, and the like. Also show excellent wear resistance,
The present invention also relates to a non-asbestos-based heat-resistant dry friction material having high strength.

[0002]

[Prior art]

Conventionally, as a friction material, those containing asbestos as a main component were often used, but as a result, it was pointed out that asbestos dust which cannot be avoided is toxic to the human body. Because the use is being regulated and, on the other hand, the need for higher-performance friction materials is increasing as the performance of vehicles, etc., is higher, it has higher performance than asbestos-based materials. In addition, there is an increasing demand for friction materials that do not use asbestos.

[0003] Recently, many proposals have been made for friction materials that do not use asbestos, and many of them use aramid fiber, glass fiber, or metal fiber as a base material.

[0004]

[Problems to be solved by the invention]

However, the friction material using the aramid fiber, the glass fiber, or the metal fiber has various problems. That is, the friction material using aramid fiber has a problem that when a brake is used continuously, the surface temperature of the friction material increases, and the aramid fiber may be thermally decomposed and cracked. The friction material using fibers has a problem that the glass fibers fall off at a high temperature and the amount of wear increases.

[0005] Furthermore, friction materials using metal fibers have the advantage of being excellent in abrasion resistance and fade resistance at high temperatures, but they are heavy, easily rust, and ignite at high temperatures. It is possible and dangerous, and the friction material using the glass fiber or the metal fiber may have the possibility of shaving or damaging the other side, such as a rotor or a drum.

[0006] Of course, friction materials using materials other than those described above have been provided, but many of them have insufficient high-temperature characteristics such as abrasion resistance at a high temperature of 400 ° C. or higher and have unstable friction behavior. It was.

The present invention has been made for the purpose of solving the above-mentioned disadvantages of the prior art.

[0008]

[Means for solving the problems]

Non-asbestos-based material that achieves the above-mentioned purpose and has stable friction performance because it shows excellent wear resistance even at high temperatures of 400 ° C or higher, as well as normal operating temperature, and has high strength and excellent heat resistance. The configuration adopted by the present invention to provide a dry friction material, a friction material containing a reinforcing fiber other than asbestos and a binder such as phenolic resin and a friction modifier such as barium sulfate, a part of the reinforcing fiber Contains 0.5 to 50% by volume of potassium titanate fiber based on the total amount of the friction material, and has a particle size of 30 as a part of the friction modifier.
0 μm or less is contained by 40% by weight or more (excluding the case where 150 mesh on only contains 5% by weight or less), and the remainder has a particle size of 1000 to 300 μm (300
(excluding μm) to the total amount of graphite as friction material
In a friction material containing 0.5 to 30% by volume or a reinforcing material other than asbestos and a binder such as phenolic resin and a friction modifier such as barium sulfate, as a part of the reinforcing fibers, It is characterized by containing potassium titanate fiber whose surface is coated with a metal or a thermosetting resin in an amount of 0.5 to 50% by volume based on the total amount of the friction material, or a reinforcing fiber other than asbestos and a phenol resin. In a friction material containing a binder and a friction modifier such as barium sulfate, a potassium titanate fiber whose surface is coated with a metal or a thermosetting resin as a part of the reinforcing fiber is used as a friction material. 0.5 to 50% by volume based on the total amount, and as a part of the friction modifier, a particle size of 300 μm
It is characterized in that graphite containing 40% by weight or more of the following is contained in an amount of 0.5 to 30% by volume based on the total amount of the friction material.

Hereinafter, the present invention will be described in detail. The reinforcing fiber used in the present invention has the formula K ₂ Ti ₆ O
₁₃ Potassium titanate fiber represented by others or organic fiber such as aramid fiber, acrylic fiber, phenol fiber, PVA fiber or inorganic fiber such as glass fiber, carbon fiber, etc., furthermore, steel fiber, copper A mixture containing one or more fibers of metal fibers such as fibers and bronze fibers is used. In short, it is only necessary to include potassium titanate fibers as a part of the reinforcing fibers.

[0010] The potassium titanate fiber may be one whose surface is coated with a metal or a thermosetting resin. Examples of the metal for surface treatment include copper and nickel. Similarly, examples of the thermosetting resin include a phenol resin and an epoxy resin that are widely used as a binder in a friction material.

As the binder, a thermosetting resin such as a phenol resin is used, and as the friction modifier, cashew dust, barium sulfate, calcium carbonate, or the like is used. These are commonly used in ordinary friction materials. In the present invention, however, the friction modifier contains graphite containing a predetermined amount or more of fine graphite having a predetermined particle size or less.

The ratio of each of the above constituent components is preferably 0.5 to 50% by volume of the reinforcing fiber (hereinafter,% relating to the component ratio indicates volume%) and the binder 5 to 30 with respect to the total amount of the friction material. %,
The friction modifier is 20 to 80%, the graphite is 0.5 to 30% based on the total amount of the friction material, and the graphite has a particle diameter of 300%.
μm or less are contained by 40% by weight or more (excluding the case where 150 mesh on is only 5% by weight or less), and the remainder has a particle size of 1000 to 300 μm (300
(excluding μm) is preferably used.

[0013]

Function and Effect of the Invention

In the present invention, since potassium titanate fibers are used as a part of the reinforcing fibers other than asbestos, no toxic asbestos dust is generated for the human body, and a predetermined amount is used as a part of the friction modifier. Graphite containing a prescribed amount of fine graphite with a particle size of less than or equals increases thermal conductivity and absorbs oxygen at high temperatures to prevent deterioration of the friction material, and it is sufficient to use potassium titanate fiber with low thermal conductivity High temperature friction characteristics.

Further, since potassium titanate fiber whose surface is coated with a metal or a thermosetting resin is used as a part of the reinforcing fiber, the potassium titanate fiber is easily compatible with other components at the time of producing a friction material. It is possible to reduce bubbles around the potassium titanate fiber, which cannot be normally avoided, and prevent the invasion of oxygen to prevent the friction material from deteriorating.

[0015] Furthermore, as a part of the reinforcing fiber, potassium titanate fiber whose surface is coated with a metal or a thermosetting resin is used, and at the same time, as a part of the friction modifier, fine graphite having a predetermined particle size or less is used. When a graphite containing a predetermined amount of is used, it is possible to further obtain a friction material having excellent friction characteristics at high temperatures.

[0016]

【Example】

Hereinafter, the present invention will be described in more detail with reference to Examples. Example 1 First, graphite containing a predetermined amount of fine graphite having a predetermined particle size or less as described below was prepared. Graphite A: contains 10 to 20% by weight of 300μm or less Graphite B: contains 20 to 40% by weight of 300μm or less Graphite C: contains 40% by weight or more of 300μm or less The balance is 1,000 to 300μm Of diameter.

Next, after a mixture containing potassium titanate fiber and graphite is uniformly mixed in the proportions shown in Table 1 (the numbers in the table represent volume%), the mixture is heated to 150 ° C. in a mold.
Compression molding was performed at a pressure of 200 kg / cm ² for 7 minutes, followed by heat treatment at 180 ° C. for 5 hours to obtain friction materials of Examples A to E. On the other hand, those obtained by variously changing the blending of the reinforcing fibers and the friction modifier were mixed uniformly, and friction materials a to f of comparative examples were obtained in the same manner as above.

The friction materials thus obtained in Examples and Comparative Examples were subjected to a friction test according to a friction performance test method specified in JASO C406 “Test method for dynamometer of a passenger car brake device”. For the friction material, the state of crack generation was examined. The surface temperature of the friction material during the fade test is 100 ° C and 400,
Table 2 shows the friction coefficient at 450 ° C., the wear amount of the friction material after the test, and the state of crack generation.

[0019]

[Table 1]

[0020]

[Table 2]

Example 2 First, a potassium titanate fiber was coated with copper by an electroless plating method to prepare a potassium titanate fiber A,
On the other hand, a phenol resin was melted at 125 ° C., and potassium titanate fiber was put therein, stirred, cooled, and pulverized to prepare potassium titanate fiber B.

The above-mentioned mixture containing the potassium titanate fibers A and B was uniformly mixed in the proportions shown in Table 3 (the numbers in the table represent% by volume), and the mixture was treated in the same manner as in Example 1. Thus, the friction materials of Examples F to O were obtained. In addition, as graphite, Example 1
Described above as graphite C, that is, graphite containing 40% or more having a particle size of 300 μm or less was used.

On the other hand, those obtained by variously changing the blending of the reinforcing fiber and the friction modifier were mixed uniformly, and friction materials g to j of comparative examples were obtained in the same manner as above. The friction materials thus obtained in Examples and Comparative Examples were subjected to a friction test in the same manner as in Example 1 and the state of occurrence of cracks was examined. The results are shown in Table 4 below.

[0024]

[Table 3]

[0025]

[Table 4]

As described above, the present invention is excellent as a non-asbestos-based friction material used as a brake pad, a brake lining, a clutch facing of a vehicle, an industrial machine or the like.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuru Kobayashi 1-1-18-1, Nishiarai Sakaecho, Adachi-ku, Tokyo (56) References JP-A-2-219888 (JP, A) (58) Fields surveyed (Int. Cl ^7, DB name) C08J 5/00 -. 5/02 C08J 5/12 - 5/22 C09K 3/14

Claims (3)

(57) [Claims] 1. A friction material containing reinforcing fibers other than asbestos, a binder such as phenolic resin, and a friction modifier such as barium sulfate, wherein potassium titanate fibers are used as a part of the reinforcing fibers. 0.5 to 50% by volume, and 300 μm in particle diameter as a part of the friction modifier.
The following components are contained in an amount of 40% by weight or more (excluding the case where a 150 mesh-on product contains only 5% by weight or less), and the remainder has a particle size of 1000 to 300 μm (however, 300 μm).
m) except for the total amount of graphite as friction material.
A heat-resistant dry-type friction material containing 5 to 30% by volume. 2. A friction material containing reinforcing fibers other than asbestos, a binder such as phenolic resin, and a friction modifier such as barium sulfate, wherein the surface of the reinforcing fibers is made of a metal or a thermosetting resin as a part of the reinforcing fibers. A heat-resistant dry friction material comprising 0.5 to 50% by volume of the coated potassium titanate fiber based on the total amount of the friction material. 3. A friction material containing reinforcing fibers other than asbestos, a binder such as phenolic resin and a friction modifier such as barium sulfate, wherein the surface of the reinforcing fibers is made of a metal or a thermosetting resin as a part of the reinforcing fibers. Contains 0.5 to 50% by volume of the coated potassium titanate fiber based on the total amount of the friction material, and has a particle diameter of 300 μm as a part of the friction modifier.
A heat-resistant dry friction material comprising 0.5 to 30% by volume of graphite containing 40% by weight or more of the following: