Cis-1,4-polybutadiene rubber is the abbreviation of cis-1,4-polybutadiene rubber, which is divided into high cis, medium cis and low cis according to the different content of cis structure, and can be divided into nickel, cobalt, neodymium (rare-earth), and titanium according to the difference of catalysts. The high cis cis cis-butadiene rubber has high elasticity, cold resistance and abrasion resistance, and is mainly used in the manufacture of tyres, rubber shoes, adhesive tapes and other rubber products.

Rare earth cis rubber has high cis content, high structural regularity, good linear structure, narrow molecular weight distribution, no branching and gelation, its blends have high tensile strength, low hysteresis loss and fatigue heat generation, and excellent flexural properties, anti-slip properties, rolling resistance. Compared with the widely used nickel BR9000, its cis-1,4 structure content is high, 1,2 structure content is low, so it has better tensile properties, abrasion resistance, the tensile strength of its vulcanised rubber, the fixed elongation stress is improved, and it is also better than nickel in heat generation, hysteresis loss, abrasion, etc. It is used in tyres to improve the high-speed performance of the tyre, improve the aging of tyres, cracking, and at the same time, increase the abrasion resistance, wet sliding resistance and reduce rolling resistance of tyres. At the same time, it can improve the abrasion resistance, wet slip resistance and reduce rolling resistance, which is in line with the requirements of "green tyre" put forward by the EU labelling law. In addition, rare earth parabens can also be used in rubber products with higher requirements for tensile and ageing resistance, as well as for modification of high-impact polystyrene and ABS resins.
In China, the common high cis-parabolic smooth butyl rubber is BR9000, which is a nickel-based product, and neodymium-based (rare-earth) smooth butyl rubber developed slowly before 2018, but with the development of "green tyres" and new energy vehicles, the development of rare-earth smooth-butyl rubber has been accelerated significantly since 2019 under the impetus of the policy, and the domestic new rare-earth smooth-butyl rubber plants or rare-earth / rare-earth rubber plants are being added one after another. REE plant or rare earth/nickel-based REE plant has been put into production in China, and the distribution is as follows (see Table 1 for details). Globally, the major rare-earth SBR enterprises include: Alangshinko, Kumho Chemical, Citation and other enterprises.