Types of commonly used active agents in the vulcanization of recycled rubber

The commonly used active agents in the vulcanization process of recycled rubber are mainly divided into two categories: inorganic active agents and organic active agents:

1. Inorganic active agents

Zinc oxide: It is the most commonly used inorganic active agent, which can accelerate the vulcanization rate, improve the crosslinking degree, and has a significant activating effect on thiazole, sulfonamide, guanidine, and thiuram accelerators. In addition, zinc oxide can also be used as a reinforcing agent, coloring agent, or thermal conductivity aid.

Magnesium oxide: As a sulfurizing active agent and inorganic promoter, it can improve the degree of vulcanization, enhance the mechanical properties of vulcanized rubber, and prolong the burning time of rubber materials. It is commonly used in products such as chlorinated butyl reclaimed rubber.

Calcium oxide: It is both an active agent and a desiccant, commonly used in recycled rubber products.

Lead oxide, stannous oxide, cadmium oxide: used respectively for high heat resistant vulcanization systems, activation of phenolic resin vulcanization systems for butyl rubber compounds, and special heat resistant vulcanization systems.

2. Organic active agents

Fatty acids (such as stearic acid): help break rubber molecular chains, facilitate processing, and can also be used as plasticizers and softeners.

Amines: They have a good activating effect on thiazole accelerators and are commonly used in the production of recycled rubber products.

Alcohols: They have an activating effect on rubber compounds containing white carbon black and can also increase the hardness of high hardness rubber compounds. They are commonly used in recycled rubber products with non carbon black reinforcing fillers.

Fatty acid salts: commonly used in products such as EPDM reclaimed rubber and nitrile reclaimed rubber, not only as activators, but also as co crosslinking agents, curing agents, etc.

3. Other active agents

Aromatic thiols, their zinc salts, and aromatic disulfides: commonly used as activators in regenerated rubber vulcanization systems.