JPS6023775B2 - Friction material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wet friction material used in an automobile clutch or a mechanical power transmission mechanism.

More specifically, the present invention relates to a friction material based on fibrous material. Conventionally known fibrous-based sea-type polishing materials include cellulose fiber-based materials, which are heat-pressed and molded by adding solid powder and phenolic resin (Special Publications No. 46).
138443), a felt sheet adsorbed with organic activated carbon and a phenolic resin are integrally molded under heat and pressure (Mochikosho 46121123), pulp and thermosetting resin are heated without applying pressure. Later, products made by hot-pressure molding (Hakama Kosho 48-24101) are known.

The main properties originally required of wet friction materials for braking include friction properties, heat resistance, abrasion resistance, durability, and oil retention.

Among these required characteristics, friction characteristics and oil retention have been improved to a nearly satisfactory level using conventional technology.
In particular, friction materials based on fibers exhibit relatively good performance. However, heat resistance and abrasion resistance are still not at a satisfactory level, and there is a strong desire to maintain and improve friction performance and improve durability. The object of the present invention is to provide good frictional characteristics, etc., which could not be achieved with the prior art.

The present invention provides a durable friction material with excellent heat resistance and wear resistance. That is, the present invention provides a friction material based on fibers, in which the constituent fibers contain aromatic polyamide fibers and pulp-like particles made of a heat-resistant polymer as a binder, and a friction performance improver is added thereto. This is a friction material that uses paper made by the same process as a base material, impregnates it with phenolic resin, and then heats and presses it to mold it. Representative examples of aromatic polyamide fibers include polymetaphenylene sophthalamide fiber (Konex ■) and polyparaphenylene terephthalamide fiber (Kevla [■), but are not limited to these. It may also be a polymer.

In addition, as the heat-resistant polymer used as a binder, aromatic polyamide polymer (for example,
1) Polyamideimide polymer (Tokusei Sho 51-10221
A typical example is pulp-like particles made by a method known as 17), but the present invention is not limited thereto.
However, the pulp-like particles made of aromatic polyamide fibers and heat-resistant polymers need to have a secondary transition point of 200°C or higher, preferably 250qo or higher and 300°C or lower. The amount of fibers can be appropriately determined depending on the intended use of the friction material, but if it is less than 5% by weight, it will not be effective in improving heat resistance and abrasion resistance.

The thickness of the fibers is suitably 3 deniers or less, preferably 1.5 deniers or more and 0.1 deniers or more, and the fiber length is suitably 5 sides or less, preferably 3 skins or less, and 0.5 skins or more. . When the fibers are thicker than 3 deniers, the smoothness of the paper deteriorates, and when the fiber length is 5 ribs or more, the cut edges will not be finished neatly when the paper is punched into a ring shape. Next, as friction performance improvers, CaC03, Shigeru S04Si02
It may be a commonly used one such as, and is not particularly limited.

The particle size of the friction performance improver is suitably 50 microns or less, preferably 10 microns or less. The amount added is preferably 10 to 4% by weight. As the phenolic resin, phenol formaldehyde resin can be used. The friction material according to the present invention mixes aromatic polyamide fiber with excellent heat resistance and high Young's modulus among fibers, and in particular, as a binder, interpulb, butadiene acrylonitrile, and polychlorobrene latex are used as secondary materials. The key point is that synthetic pulp particles, which have excellent heat resistance, are used instead of other materials.

Although linter pulp has good binding properties with fibers, it has low strength and insufficient heat resistance. Therefore, cellulose fiber,
When the amount of linter pulp increases, not only the heat resistance of the friction material becomes poor, but also the wear resistance deteriorates, leading to a decrease in durability. In addition, the friction material according to the present invention improves the heat resistance, wear resistance strength, and durability of the friction material itself, and at the same time makes it possible to increase the molding temperature after immersion in a phenolic resin bath.
Processing time can be shortened.

Example: Polymetaphenylene sophthalamide (
Mix three bases of 1.5-denier, two-rib short fibers made of Conex Teijin (registered trademark), two bases of pulp-like particles made of polymetaphenylene-sophthalamide polymer, and 20 parts of asbestos fibers. Disperse it in water to a predetermined concentration,
The dispersion liquid is transferred to a mixer, and 3 parts of the friction performance improver is added and mixed so that it is sufficiently adsorbed between the fibers.

Next, the fibers were made into a sheet using a paper machine, dried, and then soaked with 2% by weight of commercially available phenolic resin. A plate-shaped lining material was formed by hot pressing. This was punched out into a ring shape of a required size and bonded to a steel plate base material with adhesive to create a facing material for a wet clutch.
Comparative Example 3 parts of asbestos fiber and 4 parts of linter pulp were mixed and dispersed in water to a predetermined concentration.The dispersion was transferred to a mixer, 3 parts of friction performance improver was added and mixed, and the mixture was thoroughly stirred. Allow sufficient adsorption between the fibers.

Next, a clutch facing material was created in the same manner as in the example. The test method is rotational inertia mass 2.4k9・skin・s
ec2, a rotating body rotating at a rotation speed of 300 pm,
Using two disks with an inner diameter of 90 and an outer diameter of 120 ribs, the clutch is braked and stopped with a clutch pressing load of 400 k9, and its rotational energy is absorbed.

The clutch was operated in oil set at 120° C., and the clutch was operated continuously 3000 times at a rate of once every 24 seconds. As a result, the braking time of the friction material according to the present invention was 1.9 sand or less, whereas the conventional product of the comparative example had a braking time of 2.9 sand or less. It surpassed Mansho.

Therefore, it can be seen that the clutch operation of the present invention is stable. In addition, the friction material of the present invention had a weight reduction rate of 16% or less after 300 m, whereas the conventional product of the comparative example had a weight reduction rate of 30% or less.
% or more.

As described above, when the friction material according to the present invention is used, good friction characteristics can be obtained, the friction characteristics are stable even after repeated braking operations, and the durability is significantly improved.

Claims (1)

[Scope of Claims] 1. A friction material based on fibrous material, which contains aromatic polyamide fibers in its constituent fibers and pulp-like particles made of a heat-resistant polymer as a binder, and further contains a friction performance improver. In addition, the friction material is made using paper as a base material, impregnated with phenolic resin, and then molded by heating and pressing. 2 A first containing 5% by weight or more of aromatic polyamide fibers and 5% by weight or more of pulp-like particles made of a heat-resistant polymer.
Friction material described in section. 3. The friction material according to item 2, wherein the aromatic polyamide fiber has a denier of 0.1 to 2 and a fiber length of 0.5 to 3 mm.