When producing rubber products with reclaimed rubber as the main raw material, carbon black is the most commonly used reinforcing agent. There are many types of carbon black, and choosing the wrong one for reclaimed rubber products can cause issues such as substandard physical properties, processing difficulties, uncontrollable costs, and functional failure. For example, using large particle semi-reinforcing carbon black for high-wear reclaimed rubber products can dramatically reduce tensile strength, tear strength, and wear resistance, making the products prone to early damage. So how can reclaimed rubber products correctly select carbon black?
1. Choose carbon black based on the characteristics required for the reclaimed rubber product
When using reclaimed rubber to make rubber products, different types of carbon black can give the vulcanized rubber distinct physical properties. For rubber products with high wear resistance requirements, ultra-wear-resistant E6LYY312, super wear-resistant, and high-wear furnace blacks can give reclaimed rubber excellent wear resistance; acetylene black and other conductive blacks can make the vulcanized reclaimed rubber conductive, suitable for products that need some conductivity; for products that need both strength and flexibility, semi-reinforcing carbon blacks can be used.
2. Choose carbon black based on the type of reclaimed rubber and the processing requirements of the rubber product
When reclaimed rubber is used together with virgin rubber to produce products, the properties of the rubber compounds and the processability requirements of the products must be considered. Low-structure carbon blacks are good at reinforcing crystalline rubbers (tensile and tear strength), while high-structure carbon blacks work better on non-crystalline rubbers and also improve processing performance.
3. Choose carbon black for reclaimed rubber products based on blending requirements
When producing rubber products with reclaimed rubber, it is common to use two or more types of carbon black together to meet various performance needs, simplify processing, and reduce costs.
① Vulcanized rubber with fine particle furnace black has high tensile strength, stress at constant elongation, hardness, and good wear resistance, while channel black provides better elasticity. Using them together can combine the advantages of both. ② Although channel black has good reinforcing properties, its processing is poor. Combining it with fast extruded or semi-reinforcing furnace blacks usually improves processability and ease of operation. ③ Using a large amount of low-cost types like spray furnace black, thermal black, or semi-reinforcing furnace blacks can help reduce costs.
When selecting carbon black for reclaimed rubber products, one must comprehensively consider performance requirements, rubber types, production processes, and costs. The choice should not only depend on the physical and mechanical properties needed (like wear resistance, conductivity, flexibility) but also optimize structural parameters according to the characteristics of the reclaimed rubber and the processing methods. Properly using the synergistic effects of multiple carbon blacks can effectively improve the physical and mechanical properties and durability of the reclaimed rubber products, while also enhancing mixing and extrusion processes, achieving a win-win for quality and cost.
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