Friction material without asbestos and producing process

Abstract

The friction material without asbestos consists of modified phenolic resin, iron ore powder, re-burnt magnesite, alumina, clinostrengite powder, silica, barytine, wollastonite, carbon black, calcium carbonate, graphite, tire powder, zinc stearate, plant fiber, sepiolite and steel fiber. Using plant fiber and sepiolite to replace asbestos and glass fiber separately can eliminate the harm of asbestos and glass fiber to human health. The friction material has the features of high tensile strength, high toughness, heat resistance, and stable heat decay performance, and may be used in friction wafer for common vehicle and heavy truck.

Description

technical field [0001] The invention relates to the material manufacturing technology of brake friction linings for motor vehicles and mechanical braking control, especially the material manufacturing technology of medium and heavy-duty automobile drum brake friction linings. Background technique [0002] In the traditional friction material manufacturing technology, asbestos is one of the main raw materials used to manufacture automobile brake friction linings, and its content is as high as about 50%. However, asbestos has been recognized as a carcinogen, which is very harmful to human health, and asbestos dust also causes serious pollution to the environment. In addition, asbestos friction materials also have problems such as high hardness, thermal expansion, and thermal decay in terms of performance. Therefore, people began to develop non-asbestos friction materials more than 20 years ago as a substitute for asbestos friction materials. Judging from the current situatio...

AI Technical Summary

Problems solved by technology

Judging from the current situation, there are mainly semi-metallic systems, that is, friction materials that use metal fibers instead of asbestos as reinforcing materials. For example, the friction material disclosed in the CN88105160 patent uses steel fibers instead of asbestos, and its steel fiber content is 5 to 50%. The metal system friction material has good friction performance, but the metal fiber is expensive, so the cost of raw materials and production is high, and there are problems such as easy damage to the counterpart material when used

Another type of non-asbestos friction material currently researched and developed is to replace asbestos with glass fiber and other organic or inorganic fibers as reinforcement materials. ~25% replace asbestos, glass fiber as the main reinforcing material, not only is harmful to the health of workers in direct contact during the production process, but also the friction performance of its products is not ideal, and its wear rate is several times that of asbestos materials

Especially at a high temperature of 300°C, the wear rate is greater, the wear resistance of the material is poor, the service life of the product is short, and the safety and reliability are reduced. At the same time, the thermal recession and thermal recovery performance are not ideal. Reinforcement material replaces asbestos, and the cost of reinforcement material is lower than that of steel fiber, but its formula is based on the blend of nitrile rubber and modified phenolic resin as the adhesive, and the blending process of nitrile rubber and modified phenolic resin is relatively simple. Complicated, and the price of nitrile rubber is also very expensive, which also increases the production cost, making the cost of non-asbestos friction materials one to two times higher than that of asbestos friction materials

The friction material disclosed in the CN97112643 patent is to replace asbestos with 1-15% of hair and 1-5% of steel fiber. The hair as the main reinforcing material has the problems of softening and carbonization at high temperatures, which increases the wear rate and makes the material durable. The abrasiveness is not ideal, and the service life of the product is affected

Due to the heavy load and long braking time of heavy-duty vehicles, it is required that the friction plate should withstand high temperatures above 250°C, so this friction material is only suitable for medium and small vehicles, not suitable for heavy-duty vehicles.