Carbon black is the most commonly used reinforcing filler in the rubber product industry. It mainly increases the strength and tear resistance of rubber through physical adsorption and chemical adsorption, and improves the comprehensive index of rubber products. Many rubber products need to be reinforced with carbon black. For example, the amount of carbon black in passenger car tires can reach more than 20% of the total. But compounds with high carbon black content are prone to scorch during processing. Adding an appropriate amount of recycled rubber to the rubber product formula can solve this problem.
1.Causes of scorching in high carbon black compounds
Scorch is the early vulcanization that occurs when the rubber is stored or handled, which is often referred to as self-sulfur; after scorch, the rubber has increased viscosity, poor fluidity, poor adhesion, rough surface, and severe shrinkage, which directly affects subsequent processing. There are many reasons for the scorch of rubber compounds, such as improper formulation design, excessively high temperature for mixing, high temperature for storage, or long time.
Compounds with a large amount of carbon black will generate a large amount of heat during process operations such as extrusion and calendering. The heat is much higher than the heat generated by the processing of rubber compounds with low carbon black content, and the generation of heat will cause scorch problems; Therefore, the scorch of rubber compounds with high carbon black content is very likely.
2. The effect of carbon black performance on rubber scorch
Carbon black is the second largest raw material in the production of rubber products. Its specific surface area, structure, and surface activity will affect the scorch time and vulcanization rate of rubber compounds. Rubber product manufacturers need to reasonably choose the type of carbon black and control carbon in accordance with actual needs. The amount of black, if necessary, several carbon black 2LLYY0306 can be used in combination to reduce the probability of scorching of the rubber.
3. Recycled rubber can alleviate the scorch phenomenon of high-content carbon black compounds
Carbon black-containing compounds can reduce the scorch of the rubber by controlling the type and amount of carbon black during processing. However, many rubber products do require a large amount of carbon black during the production process. At this time, an appropriate amount of recycled rubber is added to the rubber product formula. Can alleviate the scorch of the rubber. Recycled rubber processed from waste rubber products has low power consumption and low heat generation in the process of mixing, hot refining, calendering, and extrusion. Therefore, the rubber containing recycled rubber produces less heat than the pure raw rubber. It can alleviate the high heat generated by carbon black, so as to achieve the purpose of reducing heat generation and scorching.
Compounds with high carbon black content have scorch problems during processing. You can try to mix the appropriate amount of recycled rubber in the formula to reduce the scorch and reduce the vulcanization and anti-reversion of the rubber. !