Composition of Friction Material Formulations（一）
Structure of Friction Material
The friction material belongs to the polymer ternary composite material, which consists of three parts:
(1) Using polymer compounds as binders;
(2) Use inorganic or organic fibers as reinforcing components;
(3) Use fillers as friction modifiers or compounding agents.
1. Binder
The organic binders used in friction materials are phenolic resins and synthetic rubbers, and phenolic resins are the main ones. Their characteristics and functions are that when they are at a certain heating temperature, they first soften and then enter a viscous flow state, generate flow and evenly distribute in the material to form a matrix of the material, and finally through the rubber vulcanization of resin curing, the fibers and fillers are bonded. Combined together, it forms a friction plate product with a dense texture, considerable strength and can meet the performance requirements of friction materials.
For friction materials, the heat resistance of resin and rubber is a very important performance index. Because when vehicles and machinery are performing braking and transmission work, the friction plates are under high temperature conditions of about 200°C to 450°C. In this temperature range, the majority of fibers and fillers are of inorganic type and thermal decomposition does not occur. For resins, rubbers, and organics, they enter the thermal decomposition region. At this time, various performance indicators of friction materials will often undergo unfavorable changes (friction coefficient, wear, mechanical strength, etc.), especially the three heats (thermal decay, thermal expansion, thermal cracking) that occur during the testing and use of friction materials. Phenomenon, its root cause is caused by thermal decomposition of resin, rubber and organic. Therefore, the choice of resin and rubber plays a very important role in the performance of friction materials. The selection of different binders will result in different friction and structural properties. Phenolic resins and their modified resins are currently used. Such as: modified cashew nut shell oil, modified nitrile powder, modified rubber and other modified phenolic resin as a binder for friction materials.
