How are friction plate materials developed? (superior)
Since the emergence of power machinery and motor vehicles in the world, friction plates have been used in their transmission and braking mechanisms. The initial friction pads used cotton, cotton cloth, leather, etc. as base materials. For example, after impregnating cotton fibers or their fabrics with rubber slurry, they were processed and formed into brake pads or brake bands. Its disadvantages: poor heat resistance. When the temperature of the friction surface exceeds 120°C, cotton and cotton cloth will gradually coke or even burn. As the vehicle speed and load increase, its braking temperature also increases accordingly, and this type of friction material can no longer meet the usage requirements. People began to seek new types of friction materials with good heat resistance, and asbestos friction materials were born.
Asbestos is a natural mineral fiber with high heat resistance and mechanical strength, long fiber length, good heat dissipation, softness and impregnation, and can be made by textile processing Asbestos cloth or tape impregnated with adhesive. Asbestos staple fiber and its cloth and belt fabrics can be used as the base material of friction materials. Moreover, because of its lower price (cost performance), it soon replaced cotton and cotton cloth as the main base material in friction materials. In 1905, asbestos brake belts began to be applied, and the friction performance, service life, heat resistance and mechanical strength of its products were greatly improved. Beginning in 1918, people used short asbestos fibers mixed with asphalt to make molded brake pads. In the early 1920s, phenolic resin began to be applied industrially. Because its heat resistance was significantly higher than that of rubber, it quickly replaced rubber and became the main binder material in friction materials. Since the price of phenolic resin is lower than that of other heat-resistant synthetic resins, asbestos-phenolic friction materials have been widely used all over the world since then.
