Metal oxide vulcanization is of great importance to chloroprene rubber, chlorobutyl rubber, chlorosulfonated polyethylene, chlorohydrin and polysulfide rubber, especially chloroprene rubber, which is commonly vulcanized with metal oxides. When chloroprene rubber is vulcanized, the allyl chloride structure produced by 1,2-polymerization is used, and there are two kinds of vulcanization mechanisms.
It should be noted that both zinc oxide and magnesium oxide can be separately cured of neoprene. When zinc oxide is used alone, the vulcanization rate is fast and scorch is likely to occur; when magnesium oxide is used alone, the vulcanization rate is slow. The best combination of the two is ZnO: MgO=5: 4. At this time, the main role of zinc oxide is vulcanization, and the rubber has good heat resistance and ensures the flatness of vulcanization. Magnesium oxide is mainly Improve the anti-coke performance of the rubber compound, increase the storage safety and plasticity of the rubber compound, and absorb the HC1 and CL2 released during the vulcanization process.
In order to improve the heat resistance of the rubber, the amount of zinc oxide can be increased (15 to 20 parts). To prepare a water-resistant compound, Pb3O4 can be used instead of zinc oxide and magnesium oxide in an amount of up to 20 parts.
The sulfur-adjusted neoprene also uses the accelerator ethylene sulfur vein (NA-22 or ETU), which improves the production safety of GN-type chloroprene rubber and improves the physical properties and heat resistance of the vulcanized rubber. The general dosage is about 1 part.