Molded vulcanizate is prepared from EPDM reclaimed rubber, that is, an ethylene-propylene rubber product that is shaped and vulcanized in a model. Model vulcanization mainly includes compression molding, transfer molding, injection molding and other production processes. EPDM reclaimed rubber has excellent high and low temperature resistance, ozone resistance and weather resistance. It can be used alone or in combination with EPDM original rubber to produce various model rubbers, which are widely used in all walks of life. When using EPDM reclaimed rubber as the main raw material to prepare the model compound, the rubber product manufacturer needs to understand the matching principle of the model vulcanized compound to meet the needs of more rubber products.
When the EPDM reclaimed rubber adopts the model vulcanization process, the following vulcanization principles need to be mastered for compounding:
1. It has suitable viscosity and good fluidity, which is convenient for the forming of EPDM reclaimed rubber;
2. It has good scorch resistance, meets the requirements of the EPDM reclaimed rubber processing process, and ensures stable storage;
3. The EPDM reclaimed rubber has a faster vulcanization speed and good vulcanization flatness;
4. The rubber compound cannot contain moisture, volatile components and components that are easily thermally decomposed to avoid foaming of EPDM reclaimed rubber vulcanized products;
5. The rubber material has no pollution or adhesion to the model, and the EPDM reclaimed rubber vulcanized product is easy to demould;
6. Meet the requirements of technical indicators such as physical and mechanical properties of model vulcanized rubber products.
When using EPDM reclaimed rubber to prepare model vulcanized rubber, it is necessary to design the formula reasonably according to the process performance and performance requirements of the product. The technical properties of the rubber compound include good plasticity, fast vulcanization speed but not easy to scorch, small compression set, good aging resistance, etc. The plasticity, vulcanization speed and scorch tendency of the rubber compound will affect each other; Mechanical properties include tensile strength, tensile stress, hardness, elongation at break, and the like.
Taking EPDM reclaimed rubber to prepare low-hardness model vulcanized rubber as an example: hardness of rubber product = rubber extrusion hardness + compounding agent dosage × hardness change value, the use of medium and super-resistant reclaimed rubber products should be avoided in the formulation of low-hardness molded EDPM reclaimed rubber products. Grinding carbon black, super wear-resistant carbon black and meteorological method white carbon black can significantly improve the hardness of the reinforcing agent; paraffin oil is often used as a softening plasticizer; EPDM reclaimed rubber model vulcanization compound uses sulfur vulcanization When the amount of sulfur is more, the cross-linking density is larger, and the hardness of the rubber compound is higher, and the amount of sulfur needs to be properly controlled.
When using EPDM reclaimed rubber to prepare model vulcanized rubber, you must master the coordination principle, and adjust the production formula and production process conditions appropriately. The editor will continue to discuss related issues with you later.
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