In rubber vulcanization, the substances that can accelerate the reaction rate of rubber and vulcanizing agent are collectively referred to as vulcanizing accelerators. Accelerator plays a very important role in rubber vulcanization. Adding a small amount of accelerator can greatly accelerate the reaction between rubber and vulcanizing agent, increase the vulcanization speed, reduce the vulcanization temperature, shorten the vulcanization time, reduce the amount of vulcanizing agent, improve the physical and mechanical properties of vulcanizate, such as increasing the tensile strength, elongation strength, wear resistance and hardness, improve the aging resistance of vulcanizate, and prevent frost spraying, Expanding the application range of vulcanizate, it can make transparent and various colors of rubber products. Therefore, accelerator is one of the essential raw materials in rubber industry.
At present, there are many kinds of accelerators used in the rubber industry, which can be divided into two categories according to their properties and chemical components: inorganic and organic.
Inorganic accelerants were used earlier, but due to their low efficiency and poor vulcanizate performance, they have been replaced by organic accelerants at present, except for a small amount of use in individual cases. Organic accelerants have high efficiency, good vulcanization characteristics, and excellent physical and mechanical properties and aging properties of vulcanizates, which make these accelerants develop rapidly.
Accelerators can be divided into dithiocarbamate, xanthate, thiuram, thiazole, hyposulfonamide, aldehyde amine, guanidine, thiourea, amine, etc. according to their chemical structures.
Promoters can be divided into four types according to the promotion effect: super promoter, medium super promoter, medium speed promoter and weak promoter.
Effect of accelerator
1. Improve the production efficiency of rubber products
Adding a small amount of accelerator into rubber compound can greatly promote the reaction between rubber and curing agent (crosslinking agent), speed up the curing reaction, shorten the curing time, reduce the curing reaction temperature, and thus reduce the cost.
2. Improve the performance of rubber products
In the production of thick products, it has a good flat effect, so that when the internal part of the product reaches positive vulcanization, the physical and mechanical properties of the surface of the product will not decline. This effect can also make the vulcanization conditions have a certain degree of freedom in the production.
3. Improve the appearance quality of rubber products
On the one hand, low sulfur consumption will not cause sulfur injection; on the other hand, due to low curing temperature and short curing time, when using organic colorants, the products can fully maintain their bright color.
In general, the application of accelerants can improve the production efficiency of rubber products, reduce product costs, improve the physical and mechanical properties of products, make thick products uniform in quality, and improve the appearance quality of products and make them bright in color.