Metal oxides are mainly used as vulcanizing agents for chloroprene rubber and chlorosulfonated polyethylene. Commonly used are zinc oxide, magnesium oxide, lead oxide, and lead trioxide. Zinc oxide has a specific gravity of 5.6 and is a white powder, non-toxic and tasteless. Zinc oxide is widely used in rubber, and it is often used as a main vulcanizing agent with magnesium oxide in general neoprene rubber. It can be used as an activator of accelerators in natural rubber and other olefin rubbers. In addition, it also has a reinforcing effect. It plays a role of shielding ultraviolet rays in the rubber resistant to sunlight. Zinc oxide is used in natural rubber and butyl rubber in an amount of 5 to 10 parts, and chloroprene rubber is generally used in combination with magnesium oxide in an amount of 5 parts. Magnesium oxide Magnesium oxide is used as a secondary vulcanizing agent in neoprene, which can prevent the neoprene from being vulcanized during mixing. This product can improve the tensile strength, set strength and hardness of neoprene. It can neutralize the small amount of hydrogen sulfide produced by halogenated rubber and the like during vulcanization or other oxidation conditions. Chlorosulfonated polyethylene rubber can give it good physical and mechanical properties, especially the permanent deformation is relatively small. But the water resistance is poor. The general dosage is 3 to 7 servings. Magnesium oxide is a white loose powder with a specific gravity of 3.2. It can gradually absorb water and carbon dioxide into the alkali or magnesium carbonate in the air to reduce its activity, so it should be kept tightly sealed.