The rubber active agent can increase the accelerator activity in the rubber product formulation, thereby reducing the amount of accelerator and shortening the vulcanization time. The active agent commonly used in the production of rubber products is divided into inorganic and organic. The inorganic active agent is mainly zinc oxide, and magnesium oxide and lead oxide are more common; the most commonly used organic active agent is stearic acid, and other weak acids, polyalcohols, and amino alcohols are also used. In actual production, different rubber products need to be matched with different varieties and doses of rubber active agents.
1. The role of active agents in rubber products
The rubber activator can activate the vulcanization system, improve the crosslinking density and aging resistance of vulcanized rubber in the rubber product formula. The addition of a small amount of active agent can also significantly improve the vulcanization strength and heat resistance of the vulcanized rubber HYL6Y7Y2Y-LYY. In actual production, zinc oxide, a commonly used inorganic rubber active agent from China factory, has multiple effects of vulcanization, reinforcement and capacity enhancement in the production of rubber products.
2. The amount of common China rubber active agents used in rubber
The most commonly used active agents in the production of rubber products are zinc oxide and stearic acid. The amount of zinc oxide is generally controlled at 2-5 servings; in order to improve the heat resistance of the rubber, the amount of zinc oxide is usually more than 5 servings. The amount of stearic acid used in rubber product formulations is generally controlled at 1-4 servings. In actual production, stearic acid can act as a lubricant, reduce the viscosity of rubber on the one hand, and promote the dissolution of zinc salt on the other hand; too much stearic acid will delay vulcanization.
3. Zinc oxide/stearic acid is combined in rubber
Metal zinc oxide and stearic acid form salts – stearate during the vulcanization of rubber. This zinc salt has a large dissolving capacity in rubber. The chelation of zinc salt and crosslink bonds protects the weak bonds in the rubber molecule, causes the rubber to form short crosslinks during vulcanization, and adds new crosslinking bonds, and increases the crosslinking density of the rubber. The polysulfide crosslinking reaction of zinc oxide or zinc salt with vulcanized rubber will reduce the sulfur atoms in the vulcanized rubber. The presence of zinc oxide can reduce the stress relaxation speed of the vulcanized rubber, and then improve the thermal stability of the vulcanized rubber.
In actual production, when zinc oxide and stearic acid are added in sufficient dosage, the reaction between the zinc salt and the accelerator can obtain a rubber with full crosslinking, fast vulcanization speed and high performance. Rubber can be divided into three categories: natural rubber, synthetic rubber and recycled rubber. Different varieties of rubber can be used alone or in combination with other rubbers. With an appropriate amount of active agent, the mechanical properties of vulcanized rubber can be further improved and the overall index of finished products can be improved.