Kaolin is widely used as a filler in the rubber industry. Adding it to latex mixtures can improve the mechanical properties of rubber, increase the mechanical strength of rubber products, enhance wear resistance and chemical stability, and extend the hardening time of rubber.
- Modification of kaolin and its application characteristics in rubber
Kaolin is an important filler for rubber products. When used as a filler in the past, it is generally believed that the product performance mainly depends on the particle size distribution and particle specific surface area. However, modern scientific research has proved that the surface of kaolin powder after beneficiation, purification and crushing has a large number of hydroxyl groups and oxygen-containing functional groups, which is acidic, and the kaolin after calcination is more acidic.
In addition, kaolin has a large specific surface area and high surface energy, resulting in poor compatibility with organic polymer systems. Therefore, when used as fillers for polymer-based materials (such as epoxy resin or vinyl resin), the surface must be modified to obtain products with better performance.
- Application of nano kaolin in rubber
Nano-kaolin can be used in various rubber products, significantly improving its mechanical and physical properties, while reducing its production costs, especially in terms of elasticity, flex resistance, barrier properties and elongation at break.
In butadiene rubber, EPDM rubber, natural rubber and nitrile rubber, nano-kaolin has better reinforcing performance than white carbon black, and it is close to the reinforcing performance of white carbon black in styrene butadiene rubber. It is suitable for tires. Side rubber, inner tube, golf rubber, rubber wire, nitrile sealing rubber, sole rubber, rubber roller, glue stick, conveyor belt rubber and other products.
In terms of mechanical properties, in the EPDM, natural rubber, and styrene-butadiene rubber used in rubber jacket/insulated cables, nanometers can be close to the current mainstream reinforcing materials, white carbon black and carbon black. Its electrical properties are far superior to other materials, comparable to calcined kaolin. Nano-kaolin is used in rubber wires and cables to achieve a combination of high mechanical properties and high electrical properties.
In natural rubber such as bladders and inner tubes, nano-kaolin can be used alone as a reinforcing material for the system, which can provide performance beyond white carbon black and close to carbon black. Adding 40-60phr can improve the mechanical properties, processing performance, and gas of the system. The performance of compact and reachable products exceeds the peak. IIR itself has very excellent barrier properties. Adding nano-kaolin, even if a small amount of 10phr is added, can increase the air-tightness of IR by more than 3 times; at the same time, the high-reinforcing properties of nano-kaolin give the system good performance.