Zinc oxide can play the following roles in rubber.
1. Vulcanizing agent: Zinc oxide as vulcanizing agent is mainly used in CR, CIIR, CSM, XNBR, CO, T and other rubbers, especially CR and CIIR.
2. Active agent: zinc oxide is the most important and widely used inorganic active agent, which can accelerate the speed of vulcanization and improve the degree of vulcanization. When used alone, its active role can not give full play to, must be used with stearic acid.
3. Reinforcing agent: zinc oxide also has a certain reinforcing effect, is a more typical inorganic reinforcing metal oxides.
4. coloring agent: zinc oxide as a white coloring agent, zinc oxide is also known as zinc white, its dosage in more than 3 parts, it can be seen in its coloring effect, but not as good as titanium dioxide.
5. Thermal conductivity: When the dosage is more than 5 parts, it can increase the thermal conductivity of the rubber material, and the general dosage is 7~15 parts, but the purity of zinc oxide is required to be very high. This is very good for hot air vulcanization and thick products vulcanization, the work of the heat will be relatively large need to dissipate heat in a timely manner of the product (such as V-belt) is very important.
6. Promoter: It is a common inorganic promoter, mainly used for vulcanization of hard rubber.
7. Heat-resistant agent: it can improve the heat resistance of NBR and hydrogenated NBR.
8. Foaming auxiliary: It can be used as auxiliary of foaming agent AC to improve foaming effect.
9. hardening agent: it has obvious hardening tendency to the rubber material (fine particle zinc oxide is especially significant), so it can be used to improve the shape stability of pressed out products and moldless vulcanized products.