JPH06159409A - Non-asbestos friction material - Google Patents

Abstract

PURPOSE:To provide non-asbestos friction material excellent in wear and abrasion resistance and of little brake noise in friction material used for brake pad, brake lining, clutch facing, etc., for automobiles. CONSTITUTION:In friction material including non-asbestos fiber components, thermosetting resin components such as phenol resin components, and filler material components such as black lead, barium sulfate, etc., at least a part of the component includes polyester liquid crystal polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction material used for automobile brake pads, brake linings, clutch facings and the like, which is a non-asbestos type friction material having good wear resistance and less squeaking. Is.

[0002]

2. Description of the Related Art Conventionally, asbestos is often used as a base material for friction materials used for automobile brake pads, brake linings, clutch facings, etc. However, asbestos is harmful to humans due to its dust. As a result, the use thereof is being regulated, and there is a strong demand for a friction material that does not use asbestos. Therefore, many proposals have been made for non-asbestos-based friction materials that do not use asbestos, but most of them use heat-resistant organic fibers, glass fibers, metal fibers, etc. as the fiber component and thermosetting phenolic resin, etc. as the binder. Resin is used as a filler component such as graphite, barium sulfate and alumina.

On the other hand, in recent years, among the performance requirements for brakes, there is an increasing demand for squeal prevention during braking, and improvements in brake systems or friction materials are being studied. Structural improvements and compositional improvements have been studied as improvements of the non-asbestos-based friction material. Specifically, a method of increasing the porosity by adjusting the content of the binder or bottom pressure molding, and rubber particles are used. Examples include a method in which a large amount is included to improve vibration absorption.

[0004]

However, the above method has a drawback in that other performance must be sacrificed to some extent. For example, a method of simply increasing the porosity may weaken the bond between the binder and another friction material. However, the method using rubber particles reduces the strength of the friction material, and as a result, it is difficult to obtain sufficient results in terms of wear resistance. Therefore, the problem to be solved by the present invention is to provide a non-asbestos-based friction material which causes less squeaking without impairing other performances.

[0005]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems. Its constitution is a fiber component other than asbestos, a thermosetting resin component such as phenol resin, graphite, A friction material containing a filler component such as barium sulfate is characterized in that a polyester liquid crystal polymer is contained in at least a part of its constituent components.

That is, the inventor of the present invention has conducted extensive research for the purpose of obtaining a non-asbestos-based friction material with less squeaking during braking, and as a result, by incorporating a polyester-based liquid crystal polymer into the friction material constituent, The inventors have accomplished the present invention by knowing that they can achieve the above objects. Although there are many kinds of polyester liquid crystal polymers, the present invention preferably has a structure having a rigid rod-shaped molecular chain and a strong intermolecular force, and examples thereof include those having the following structures.

[Chemical 1]

[Chemical 2]

Such a polyester type liquid crystal polymer has an elastic modulus close to that of a metal, but has a property of absorbing a vibration which cannot be obtained by a metal, that is, a vibration damping property. Generally, a material having a high elastic modulus such as a metal transmits vibration well, and a soft material such as rubber absorbs a vibration well. It has the property of absorbing vibration. The content of the polyester liquid crystal polymer is preferably 0.5 to 20% by volume with respect to the total amount of the friction material,
If it is 0.5% or less, the effect is small, and if it is 20% or more, the friction performance may be deteriorated.

Concerning the constituents of the friction material of the present invention, conventional ones can be used except that the polyester type liquid crystal polymer is used. Examples of the constituents used as the fiber component include organic fibers such as aramid fibers, glass fibers and locks. Inorganic fiber such as wool, ceramic fiber, potassium titanate fiber, copper,
Examples include metal fibers such as bronze, aluminum, and brass. Examples of binders include thermosetting resins such as phenolic resins, urea resins, melanin resins, or modified resins thereof, polyacetals, aromatic polyimide resins, fluororesins, etc. The heat-resistant resin of
Examples include metal powder, molybdenum disulfide, cashew dust having a lubricating effect, ceramics, abrasives such as zirconium silicate, barium sulfate, calcium carbonate and the like.

[0009]

The friction material of the present invention is a non-asbestos friction material, and since it contains a polyester liquid crystal polymer having a vibration damping property in at least a part of its constituents, it produces less squeaking during braking, and the friction material. Wear resistance is improved.

[0010]

EXAMPLES Next, examples of the present invention will be described. Using Kevlar as the fiber base material, phenol resin as the binder, polyester liquid crystal polymer as the filler component, cashew dust, tire particles, rubber particles, aluminum particles, graphite, calcium carbonate, and barium sulfate, and stirring them with a stirrer. the uniformly mixed, at room temperature, after pre-molded under a pressure 180 kg / cm ^2, temperature of 160 ° C., for 8 minutes heat pressure molding at a pressure 210 kg / cm ^2, then the table 1 was heat-treated for 5 hours at a temperature 220 ° C. The friction materials of Examples A to C shown were obtained. "Econol E101-S" manufactured by Sumitomo Chemical Co., Ltd. was used as the polyester liquid crystal polymer.

Further, the friction materials of Comparative Examples a and b containing no polyester type liquid crystal polymer were similarly obtained. In addition, the numerical value in a table shows volume%. Table 2 shows the results obtained by mounting the friction materials a and b of Examples A to C and the comparative example produced by the above method on a small passenger car, and performing a wear test by a test code of JASO, C427-83 and a squeal test by an actual vehicle. Show. In the squeal test, Examples A to C obtained better results than Comparative Examples a and b. Comparative Example b had an evaluation close to that of Examples A to C, but the wear performance deteriorated because the rubber particles were increased.

[Table 1]

[Table 2]

[0012]

As described above, the non-asbestos-based friction material of the present invention which does not contain asbestos as a fiber base material includes organic fibers such as aramid fibers, inorganic fibers such as rock wool, metal fibers such as copper fibers,
Consists of a binder such as phenolic resin and a filler component such as graphite and barium sulfate. As a result of including a polyester liquid crystal polymer in at least a part of its constituent components, squeaking during braking is reduced as described above. Therefore, it is suitable as a friction material used for automobile brake pads, brake linings, clutch facings and the like.

Claims (3)

[Claims] 1. A friction material containing a fiber component other than asbestos, a thermosetting resin component such as a phenol resin, and a filler component such as graphite and barium sulfate, and at least a part of the constituent components is a polyester-based friction material. A non-asbestos friction material containing a liquid crystal polymer. 2. The non-asbestos friction material according to claim 1, wherein the content of the polyester liquid crystal polymer is 0.5 to 20% by volume based on the total amount of the friction material. 3. Fiber components other than asbestos include organic fibers such as aramid fibers, glass fibers, rock wool, ceramic fibers, inorganic fibers such as potassium titanate fibers, copper, bronze,
The non-asbestos friction material according to claim 1, which is a metal fiber such as aluminum or brass.