According to the catalytic system, the technologies used by the world's shunding rubber production companies can be divided into five major systems: nickel, cobalt, lithium, titanium, and rare earth (neodymium).Titanium, nickel and cobalt system is the mainstream in elimination trend, rare earth system in the development stage, lithium is butadiene rubber is mainly used for production, impact polystyrene modification for the nickel butadiene is our country in the 1960 s the successful development of highly active nickel catalysts, respectively in 1965 in jinzhou, lanzhou, began to industrialized production, butadiene rubber production of new technological achievements in 1985, special-class award of national scientific and technological progress, after half a century of several generations efforts, China's nickel production technology and nickel butadiene product quality in the world advanced level.
Characteristics of nickel catalytic system:
1. Nickel catalytic system is a multicomponent system. The dosage ratio, feeding mode and aging mode of catalysts not only affect the activity of the catalytic system, but also affect the molecular weight of the polymer.
2, nickel catalyst system stability, polymerization temperature, to adapt to a wide range, the reaction temperature above 120 ℃, the system still not inactivation, has good temperature resistance.
3. The nickel catalytic system has good directivity and is less affected by the amount of catalyst and the concentration of monomer.
4. The nickel catalyzed system caused a large number of chain transfer of butadiene during the polymerization process, leading to chain termination.
Polymerization characteristics of rare earth catalytic system:
1. Saturated hydrocarbon hexane is used as solvent, which is conducive to environmental protection;
2. High monomer conversion rate, even reaching 100%;
3. It is not easy to produce cross-linking reaction and generate gel.