Natural Rubber Encyclopedia

How to design a natural rubber product formula for high temperature vulcanization

Create Date:2019-09-09 08:26:40Click volume:790
How to design a natural rubber product formula for high temperature vulcanization

When the natural rubber is vulcanized, the vulcanization temperature is usually controlled between 140-150 ° C, and should not exceed 160 ° C. Otherwise, it is easy to cause problems such as scorch and vulcanization in the processing; high temperature will also cause internal bond breakage of natural rubber. The physical and mechanical properties of the products are degraded, and the natural rubber products with large thickness are prone to the problem of internal and external vulcanization unevenness when vulcanized. However, high-temperature vulcanization can significantly improve production efficiency, so the manufacturer of natural rubber products really missed the "high-temperature rapid vulcanization" 1JLYY99?
In actual production, natural rubber rubber products can appropriately increase the vulcanization temperature and improve production efficiency by adjusting the vulcanization system of rubber products and selecting a suitable production process.

1. Reasonable selection of natural rubber product vulcanization system

Sulfur is the most commonly used vulcanization system in the production of natural rubber products. The vulcanized rubber has high mechanical strength, good elasticity and excellent wear resistance. Appropriate increase of sulfur dosage can increase the crosslink density of rubber compound and further improve the comprehensive index of natural rubber products. However, when sulfur is used as a vulcanizing agent, high-temperature vulcanization of natural rubber is prone to problems; on the contrary, appropriately reducing the amount of sulfur can improve problems such as local scorch, uneven vulcanization or vulcanization in the high-temperature vulcanization.

Sulfur itself has different cross-linking morphology between rubber molecules. It can be composed of 1-2 sulfur molecules and short molecular chain cross-linking. It can also be composed of multiple sulfur molecules. The high-temperature vulcanization is dominated by long molecular chains; long molecular chains are under high temperature conditions. It is easy to cause thermal decomposition, which leads to a decrease in the crosslink density of the rubber compound and the occurrence of a sulfurized reversion.

The experiment shows that the vulcanized natural rubber is vulcanized under the same high temperature condition, and the indexes of the vulcanized material after vulcanization are more stable. Therefore, when selecting a high-temperature vulcanized natural rubber product manufacturer, it is best to choose an effective vulcanization system when designing the vulcanization system; if sulfur vulcanization must be used, the amount of sulfur should be appropriately reduced.
2. Choose a suitable vulcanization process

At present, the vulcanization methods commonly used in the production of natural rubber products are flat vulcanization, continuous vulcanization and injection vulcanization. When the natural rubber is selected for high temperature vulcanization, the continuous vulcanization technology can solve the problem of uneven deformation of natural rubber and uneven thickness during vulcanization; when vulcanization at high temperature, the vulcanization temperature must be properly controlled to avoid the retention of the rubber at the injection end nozzle and prevent scorch. and many more.

High-temperature vulcanization is undoubtedly beneficial to improve production efficiency. Reasonable adjustment of the vulcanization system of natural rubber products and adjustment of vulcanization process conditions can not only improve production efficiency, but also ensure the normal production of natural rubber products. But Xiao Bian still wants to remind everyone: natural rubber is still better to avoid high temperature vulcanization.