The so-called heat-resistant rubber products are rubber products that can be used for a long time in a high-temperature environment and maintain their physical and chemical properties, and have high requirements for the heat resistance of rubber compounds. EPDM reclaimed rubber has the basic performance characteristics of EPDM original rubber, high and low temperature resistance, excellent aging resistance, and can be used alone or in combination with EPDM rubber to produce heat-resistant rubber products such as heat-resistant hoses, heat dissipation hoses, sealing strips, etc. When using EPDM reclaimed rubber to produce heat-resistant rubber products, the reinforcing filling system not only affects the heat resistance of vulcanized rubber, but also is closely related to the production cost.
When designing the reinforcing filling system of EPDM reclaimed rubber heat-resistant rubber products, it is necessary to consider both the performance requirements and the cost of the products. In general, the stronger the reinforcement of the material, the more obvious the decreasing trend of the elongation of the obtained EPDM reclaimed rubber vulcanized rubber during aging, and the worse the heat-oxygen aging effect. Inorganic fillers are more heat-resistant than carbon black, and the heat-resistant combinations are silica, activated zinc oxide, magnesium oxide, alumina and silicate that are more suitable for heat-resistant combinations in inorganic fillers.
The reinforcing agents and fillers commonly used in the production of EPDM reclaimed rubber products are as follows.
Carbon black: Carbon black can significantly improve the tensile strength, abrasion resistance and tear resistance of rubber. Different types of carbon black have different structural and surface properties; When using EPDM reclaimed rubber 2SLYY1025 to produce heat-resistant rubber products, you can use an appropriate amount of carbon black that helps to improve the heat resistance of the rubber compound, such as high wear-resistant carbon black, fast-pressed furnace black, semi-reinforcing carbon black, furnace carbon black, groove carbon black, spray carbon black, pyrolysis carbon black, etc., which can improve the heat resistance of rubber to a certain extent, and select suitable varieties of carbon black in combination with physical and mechanical properties.
White carbon black: It can improve the heat resistance, oil resistance and compression set resistance of EPDM recycled rubber.
Zinc oxide: It plays the role of an activator in EPDM reclaimed rubber, which helps to improve the vulcanization rate and heat resistance of reclaimed rubber.
Hard clay: It can improve the hardness and heat resistance of EPDM reclaimed rubber, while reducing costs.
Calcium carbonate: light calcium can increase the volume of rubber, reduce costs, and improve the hardness and rigidity of reclaimed rubber; Heavy calcium particles are larger and are mainly used to reduce costs and increase volume.
Staple fibers: Staple fibers such as cotton fibers, polyester fibers, polyamide fibers, etc., can improve the tensile stress, tear strength, abrasion resistance and cut growth resistance of EPDM. The interaction among the rubber matrix and the fibers can be improved by methods such as tackifying the fit, fiber surface treatment or using compatibilizers, thereby improving the reinforcing properties.
Vulcanized rubber powder: Vulcanized rubber powder can be used as an extender, but the reinforcing performance is poor. When filling vulcanized rubber powder in EPDM products, attention should be paid to the migration of vulcanizing agent to the rubber powder, especially when using rubber powder of unsaturated diene rubber.
Talc: It can improve the hardness and rigidity of rubber while providing certain heat resistance.
Mica powder: It has excellent heat resistance and electrical insulation, and is suitable for rubber products with high temperature and electrical insulation requirements. Graphite powder: It has good lubricity and heat resistance, and is suitable for high-temperature seals and hoses.
In practice, different types of fillers have a certain influence on peroxide vulcanized heat-resistant rubber. EPDM reclaimed rubber must be paid special attention to the use of peroxide vulcanization in the production of heat-resistant rubber products. The editor will continue to discuss related issues with you in the future.
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