EPDM reclaimed rubber is made from EPDM die head rubber, unvulcanized EPDM rubber, or waste EPDM rubber products such as sealing strips. It retains the basic performance characteristics of EPDM raw rubber, can be used alone or combined with raw rubber to produce various rubber products, effectively reducing raw material costs. What should be noted when choosing EPDM reclaimed rubber for EPDM rubber products? How to correctly use EPDM reclaimed rubber?
1. Consider the compatibility among EPDM reclaimed rubber and the basic performance indicators of rubber products
When choosing EPDM reclaimed rubber to reduce costs, the first step is to consider the compatibility among reclaimed rubber and basic rubber product indicators, including rubber content, tensile strength, elongation at break, Mooney viscosity, fineness, and environmental standards.
For high-performance EPDM rubber products such as automotive sealing strips and cable sheaths, choose EPDM reclaimed rubber with a high EPDM content, which contains ≥60%, offering good elasticity and strength; For ordinary EPDM rubber seals E6LYY312 you can choose EPDM reclaimed rubber with a slightly lower content, which is even more affordable; For extruded EPDM rubber products, it is recommended to choose 60-80 mesh filter EPDM reclaimed rubber, which has high fineness and no impurities, ensuring a smooth extrusion surface and stable dimensions; For environmentally friendly rubber products, choose environmentally friendly EPDM reclaimed rubber.
In terms of processing performance, it is recommended to choose EPDM reclaimed rubber with a Mooney viscosity among 40-70, as it has good fluidity and plasticity. Excessive Menti viscosity in EPDM reclaimed rubber leads to increased energy consumption in mixing and uneven filler dispersion; If the Mooney viscosity is too low, it may lead to insufficient crosslinking density of EPDM reclaimed rubber vulcanized adhesive, affecting the aging resistance and physical and mechanical properties of the product.
2. Consider the ratio of EPDM reclaimed rubber to EPDM base rubber in EPDM rubber products
When using EPDM reclaimed rubber to replace part of EPDM base rubber in rubber production, the proportion of reclaimed rubber should be reasonably determined based on the product's performance requirements.
For EPDM rubber products with strict requirements for resistance to high and low temperatures, ozone resistance, compression permanent deformation, or mechanical strength, such as automotive radiator rubber hoses, 20%-40% EPDM reclaimed rubber can be added, adopting a "base rubber as the main material + a small amount of reclaimed rubber" to ensure the product's tensile strength and compression permanent deformation; Low-stress EPDM rubber products such as ordinary sealing strips and rubber sheets can be mixed with 30%-50% EPDM reclaimed rubber; For low-load, non-core load-bearing EPDM rubber products, such as waterproof membranes, the formulation of all-EPDM reclaimed rubber can be choosen to further reduce raw material costs.
3. Consider the vulcanization system of EPDM reclaimed rubber and EPDM base rubber
When producing rubber products mainly from EPDM rubber, two common systems are sulfur vulcanization and peroxide vulcanization. During desulfurization, the degree of fracture of the original vulcanized crosslinking bonds varies among EPDM reclaimed rubber from different sources, and residual active groups affect the vulcanization characteristics of the compound. When EPDM rubber products are mixed with EPDM reclaimed rubber, it is necessary to choose the appropriate EPDM reclaimed rubber according to the vulcanization system of the original rubber; EPDM rubber products with peroxide vulcanization should avoid using reclaimed rubber with high sulfur residues to prevent interference with crosslinking structures and reduce heat aging resistance.
4. Consider the quality stability of EPDM reclaimed rubber
As a product of desulfurization and recycling of waste rubber, EPDM reclaimed rubber has fluctuations in raw material sources, which means that the physical property differences among batches are usually greater than those of the base rubber. Manufacturers of rubber products using EPDM reclaimed rubber test each batch, focusing on hardness, tensile strength, and elongation at break. Small-scale trial mixing verification can be conducted to ensure batch stability and avoid a decline in finished product pass rates caused by quality fluctuations.
When adding EPDM reclaimed rubber to EPDM rubber products to reduce costs, it is necessary to choose appropriate reclaimed rubber based on the product's usage environment, physical and mechanical performance requirements, processing technology, and the type of raw rubber, reasonably determining the dosage ratio, thereby reducing raw material costs and production energy consumption while ensuring the product's performance and lifespan.
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