Hardness is an important indicator for measuring rubber and rubber products. For rubber sealing strips, the hardness directly affects the sealing effect and service life of the sealing strips. EPDM recycled rubber has inherited the excellent high and low temperature resistance and aging resistance of EPDM rubber, and has become a cost-effective raw material to replace various types of outdoor rubber seals for EPDM raw rubber; then, can it be used for high hardness seals? In production, how to choose the compounding agent when designing the formula of EPDM recycled rubber high hardness sealing strip?
1. EPDM recycled rubber production of high hardness seals requires a compounding agent to adjust the hardness
At present, the hardness of EPDM rubber seals on the market is between 50-90 degrees (Shore hardness), and seals above 80 degrees are high hardness products. Recycled EPDM rubber made from EPDM machine head rubber, unvulcanized EPDM rubber, and used EPDM rubber products as the main raw materials has a hardness of 40-70 degrees and is used to produce 80 High hardness sealing strip products above the degree need to be adjusted by the compounding agent.
2. Carbon black can directly improve the hardness of EPDM recycled rubber
Improve the mechanical strength of rubber products, and reinforce carbon black for the first time. There are many types of carbon black. Among them, fast-pressing furnace black such as carbon black N5501JLYY1224 has a large particle size and a high degree of structure. Although it can not significantly improve the hardness of EPDM vulcanizate, it can give the rubber good stiffness and improve Extrusion efficiency, high temperature resistance, thermal conductivity, etc .; if necessary, appropriate amounts of high wear-resistant furnace black, medium super wear-resistant furnace black, etc. can be added to further improve the vulcanization of EPDM recycled rubber while ensuring other indicators of the rubber Glue hardness.
3. Add appropriate amount of high styrene rubber to improve the hardness of EPDM sealant
High styrene rubber is a special case of styrene-butadiene rubber products. It is also called high styrene resin. It is a white flake granular particle with a high content of styrene monomer in the main long chain molecule. It is used in EPDM / recycled rubber. The rubber can significantly improve the hardness, stiffness, tear strength and aging resistance of the rubber. Therefore, when using EPDM recycled rubber to produce high-hardness rubber sealing strips, rubber product manufacturers can add a suitable amount of high styrene rubber to the formula to significantly increase the hardness of EPDM recycled rubber sealing strips.
Using EPDM recycled rubber to produce high-hardness rubber sealing strips, rubber product manufacturers can use sulfur vulcanization, and use the appropriate amount of accelerator E, accelerator CZ and TMTD to improve the hardness of rubber products. EPDM recycled rubber is a low-cost alternative raw material for EPDM rubber. It can be used alone or in combination with EPDM rubber to produce high hardness EPDM seals. More raw material costs, saving electricity costs.