A large part of the sealing ring products on the market is produced by using EPDM reclaimed rubber. Such a sealing ring product can adapt to various high and low temperature environments, and is resistant to corrosion, aging, and has a long service life. However, after entering the market, many rubber products companies have discovered air leakage in EPDM reclaimed rubber seals. Why?
Not only is the EPDM sealing ring, but all rubber products will experience physical degradation in high temperature environments. This is because the internal chains of the rubber will break and form active radicals. These free radicals will Causes breakage or cross-linking of rubber polymer chains, and molecular heat movement is too intense, resulting in difficulty in crystallization of rubber molecules and lowering of crystallinity. As a result, physical indexes such as tensile strength and elongation at break of rubber products are reduced, affecting the performance of rubber products. With life expectancy.
On the other hand, the most important function of the EPDM reclaimed rubber sealing ring is sealing. Its working principle is that the sealing ring is compressed, and the deformation occurs in the cross-section so that the stress and the contact surface are tightly combined to play a sealing role. In hot summer, the temperature rises and the air pressure decreases. The difference between the sealing pressure and the atmospheric pressure in the sealed environment increases, causing the seal ring product to move outwards; at the same time, the seal ring hardness decreases (tensile strength and elongation at break). Will also reduce), compression rate is too large, the stress is reduced, permanent deformation is too fast, and then cause air leakage phenomenon, and ultimately affect the sealing performance of EPDM recycled rubber products.
It can be seen that the higher the hardness of the EPDM reclaimed rubber, the greater the intermolecular force within the rubber and the better the sealing effect of the sealing ring; therefore, the rubber product manufacturer should choose a high hardness without affecting the elasticity of the sealing ring as much as possible. The EPDM reclaimed rubber is the basis for ensuring the sealing effect produced by the EPDM reclaimed rubber to have a good sealing effect and a long service life; it is also possible to reasonably add reinforcing agents and fillers in the EPDM reclaimed rubber formulation. , To increase the cross-linking density of the rubber compound and to increase the hardness of the vulcanized rubber compound.
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