Under static load, rubber has two properties of strength and elasticity. Tensile strength is the main index to measure the mechanical properties of rubber. When EPDM and EPDM reclaimed rubber are used together to produce static sealing strips, vulcanization system and reinforcement The type and amount of the compounding agent in the filling system and the softening system directly affect the mechanical properties of the rubber compound. How to choose the reinforcing agent, filler and softener in the EPDM sealing strip formula, and how to improve the mechanical properties?
3. Adjust EPDM static seal strip reinforcement system
The rubber product reinforcement system is composed of two parts: a reinforcing agent and a filler. The reinforcing agent can improve the mechanical strength of the EPDM rubber, and select high wear-resistant carbon black and super wear-resistant furnace black in the black static sealing strip. The reinforcing carbon black can obviously improve the mechanical strength of the EPDM sealing strip. The light-colored EPDM sealing strip can improve the static mechanical properties while improving the heat resistance of the sealing strip by using the white carbon black reinforcing; Black can also increase the tensile strength of EPDM vulcanizate, and can reduce the amount of carbon black to a certain extent and reduce the cost of raw materials.
The filler can increase the volume of the product and reduce the production cost in the EPDM sealing strip. However, the excessive use of the non-reinforcing inorganic filler will lead to an increase in the tear strength of the static sealing strip and a decrease in the tensile strength and the like. The mechanical properties of ethylene-propylene rubber/recycled rubber static sealing strips are degraded; rubber sealing strip processing manufacturers need to reduce the amount of inorganic fillers as much as possible, and carry out surface modification treatment if necessary. For example, activated calcium carbonate has a certain reinforcing effect in the rubber compound.
4. Adjusting the EPDM static seal strip softening system
Many rubber products manufacturers adjust the hardness of rubber products by adjusting the amount of reinforcing agent and softener to coordinate the relationship between various mechanical indexes of rubber products. Therefore, the types and dosages of softeners in EPDM static sealing strip formulations will also Affect the mechanical properties of the seal. EPDM rubber is a non-polar saturated rubber. Avoid using paraffin oil with low unsaturation as much as possible. Reduce the amount of naphthenic oil containing aromatic compounds and unsaturated compounds. The amount of paraffin oil and naphthenic oil must be used. Control between 10-25 and 10-50 parts to ensure that the EPDM/regenerative seals maintain good mechanical properties under static conditions.
At present, more and more static sealing strip products are produced by using EPDM rubber and EPDM reclaimed rubber as main raw materials, such as automotive sealing strips, door and window sealing strips, and studying the influencing factors of mechanical properties of EPDM static sealing strips. It is of great significance to improve the comprehensive performance of EPDM sealing strips and prolong the service life. If necessary, it can also increase the application range and dosage of EPDM reclaimed rubber in EPDM static sealing strips.