The production technologies of cis-1,4-polyisoprene rubber in the world mainly include Russian yaroslav process, American Gutrich process, Italian Snam process and Dutch Shell process. Isoprene rubber is basically divided into three series according to its catalytic system: lithium system, titanium system and rare earth system. Up to now, the production of isoprene rubber mainly adopts the first two catalytic systems, and after decades of development, the technology is relatively mature. In 1966, China developed titanium isoprene rubber jointly by Jihua Research Institute and Changchun Institute of Applied Chemistry.
For rare earth catalyst system, Leningrad Synthetic Rubber Research Institute used rare earth element Nd (Neodymium) instead of Ti in the original polymerization catalyst to make a new generation of catalyst, which can increase the content of cis-1,4-isoprene rubber in raw rubber and avoid insoluble matter. Raw rubber has the advantages of large average relative molecular weight, narrow distribution, short vulcanization processing time and less catalyst consumption, but the cost is high. This kind of catalyst was tested in the pilot plant in the late 198s, and the industrial test was carried out in the 1t/a plant of Bashkiria synthetic rubber. In 197, isoprene rubber catalyzed by rare earth was developed, and a 5-ton/year pilot plant was established in Jihua. After long-term operation, dozens of tons of products were provided. In 1973, the technology was amplified and tested in Yanshan Petrochemical Company's 1,-ton cis-butadiene rubber plant, and passed the preliminary finalization and appraisal at the ministerial level in 1975. In 1987, the basic design of the 13,-ton/year isoprene rubber plant was completed, and in the same year, the technology of rare earth catalytic synthesis of isoprene rubber passed the technical appraisal of the former Ministry of Chemical Industry. In 1992, Gao Qiao Petrochemical Company also put forward a pre-feasibility report on building a 1,-ton/year isoprene rubber plant. Beijing Rubber Industry Research and Design Institute has also done a lot of research on isoprene rubber since 196s, and has initially formed a set of application technologies. Although the relevant departments have demonstrated the isoprene rubber project for many times, the production of isoprene rubber is still blank in China, and there are two main points of debate: First, it is difficult to collect C5; The second is whether the price of isoprene rubber can compete with natural rubber. Faced with huge market opportunities, many foreign enterprises have begun to expand the production capacity of isoprene rubber and the production line of polyisoprene. China has the synthesis technology of rare earth isoprene rubber, and the development of isoprene rubber should also be put on the agenda.