The role of zinc oxide in rubber

Mingpai
2024-05-29 10:42:21

Zinc oxide plays a multitude of crucial roles in the rubber industry, including but not limited to the following points:

Sulfur vulcanization promotion and activation: When zinc oxide combines with stearic acid, it forms zinc soap, which not only enhances the solubility of zinc oxide in rubber mixtures but also complexes with sulfur accelerators, hastening the vulcanization process. This shortens the curing time and improves vulcanization efficiency.
Enhancement of crosslink density: Through reactions with sulfur promoters, zinc oxide aids in forming more stable cross-link structures, resulting in shorter and denser cross-links. This strengthens the physical and mechanical properties of the rubber, such as tensile strength and wear resistance.
Improvement of physical properties: The addition of zinc oxide significantly boosts properties of rubber products like thermal conductivity, wear resistance, tear resistance, and tensile strength, making the end products more durable.
Anti-aging and corrosion resistance: During vulcanization and use, zinc oxide reacts with detrimental substances (e.g., H2S) produced, forming new cross-links that protect the sulfur network, thereby enhancing the aging resistance and corrosion resistance of rubber products.
Reinforcement and filling function: Acting as a reinforcing agent, zinc oxide can increase the mechanical properties of rubber, such as hardness and compressive strength. It also serves as an excellent filler, potentially substituting or partially replacing other fillers like carbon black in some instances.
Coloring and transparency: In white or transparent rubber products, zinc oxide is used as a colorant, providing good whiteness and transparency. Compared to alternatives like zinc carbonate, products made with zinc oxide exhibit better clarity.
Cost-saving and environmental friendliness: By boosting the activity of accelerators, zinc oxide allows for reduced usage of accelerators and other additives, thereby lowering production costs and potentially reducing environmental impact.