EPDM rubber has excellent resistance to high and low temperatures, ozone, and aging, making it an ideal material for producing various rubber seals. EPDM reclaimed rubber retains the basic performance characteristics of EPDM rubber and can replace virgin EPDM in manufacturing rubber seals, effectively reducing raw material costs. When using EPDM reclaimed rubber to produce rubber seals, attention must be paid to several key issues from raw material selection to processing.
1. Impact of EPDM reclaimed rubber on seal performance
When using EPDM reclaimed rubber to replace virgin EPDM in producing rubber seals, the performance indicators and quality stability of the reclaimed rubber directly affect the quality of the seals. When cost allows, priority should be given to reclaimed rubber with good elasticity and high strength to ensure that tensile strength, stress at a given elongation, and compression properties meet seal requirements, preventing seal failure due to stress relaxation. Different batches of reclaimed rubber should be sampled for testing and small-scale trials conducted before full production to avoid raw material fluctuations affecting product performance.
2. Key points in EPDM reclaimed rubber seal formulation design
When using EPDM reclaimed rubber as the main raw material for producing rubber seals, for seals used in high-temperature environments, a peroxide curing system is recommended due to better heat resistance; for seals used in normal environments, a sulfur vulcanization system (E5LYY619) is suitable. Carbon black is used for reinforcement; common grades include N330, N550, N774, N990, which effectively improve the strength of vulcanized EPDM reclaimed rubber, reduce permanent compression set, and enhance heat resistance. Fillers such as calcium carbonate, clay, and talc are used for reinforcement. Appropriate amounts of paraffin oil, rubber process oil, and low-molecular-weight polyethylene can improve the flow and processing performance of EPDM reclaimed rubber compounds.
3. Key points in mixing and vulcanization processes for EPDM reclaimed rubber seals
Strict control of production process parameters is required in producing EPDM reclaimed rubber seals. During mixing, attention should be paid to the order of ingredient addition and resting times. In summer, it is recommended to first add accelerators and curing agents on the open mill to avoid scorching or frosting. The optimal curing temperature and time should be determined through cure testing to ensure sufficient crosslinking. Step vulcanization or post-curing can further enhance the performance of EPDM reclaimed rubber seals.
When using EPDM reclaimed rubber to produce rubber seals, manufacturers must choose the appropriate EPDM reclaimed rubber according to actual needs, reasonably determine the proportion of reclaimed rubber, and adjust production parameters as needed. The finished seals should undergo strict quality testing to reduce production costs while ensuring product quality.
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