China’s rare-earth rubber trades at 22,500 yuan a tonne, about 35% above standard rubber

China is testing whether a premium rubber can win a place in electric-vehicle tires. Rare-earth cis-butadiene rubber, made with a rare-earth catalyst, now has a Xinjiang plant rated at 100,000 metric tons a year, about 110,000 U.S. tons. It also trades at a higher price than conventional synthetic rubber.

Rubber Carries A Premium

China Rubber Industry Association data published Nov. 2 quoted rare-earth grade ND9106 at 22,500 yuan (about US$3,400) per metric ton during Oct. 26 to Nov. 1. Conventional BR9000 in Shandong province was quoted at 16,660 yuan per metric ton, so the rare-earth grade carried a premium of about 35%.

For tire makers, the rubber offers better wear resistance, greater strength and lower rolling resistance, and wider domestic production could make it more widely available.

Xinjiang Plant Passes Trial

A production unit at Dushanzi Petrochemical Company in Karamay, Xinjiang, completed a successful trial run on June 27, producing premium-grade rare-earth cis-butadiene rubber. The Chinese Academy of Sciences’ Changchun Institute of Applied Chemistry announced the result July 16.

The institute called the achievement a “major breakthrough” and said the core technologies are “fully under domestic control.” It said the project would help meet “urgent demand for high-end grades,” support the petrochemical new-materials industry and help “safeguard supply-chain security.”

The process makes two national-standard grades, BR1240 and BR1260, which differ in Mooney viscosity, a standard measure of rubber viscosity and processability. The rubber is made by polymerizing butadiene with a rare-earth catalyst, which helps control the polymer’s molecular structure and, in turn, its mechanical properties.

Why EV Tires Need It

Electric cars tend to be heavier than comparable gasoline vehicles and deliver high torque during acceleration, which places greater demands on tire durability. Low rolling resistance reduces the energy lost as tires deform and roll, while wear and fatigue resistance can extend tire life under repeated stress.

Heavy-duty vehicles also benefit from rubber that can withstand high loads, repeated deformation and heat build-up. Greater resistance to tearing and fatigue can improve durability under demanding conditions.

The institute says the rare-earth version beats conventional nickel-based butadiene rubber on wear resistance, strength, fatigue and tear resistance, low-temperature performance, heat build-up and rolling resistance.

The same properties could matter for military tires and other high-performance rubber parts, though the institute has disclosed nothing about supplying weapons or military vehicles.

Six Decades Of Research

The industrial result builds on more than six decades of work at the institute. In 1964, scientists Ouyang Jun and Shen Zhiquan published a paper on rare-earth compounds as catalysts for stereospecific polymerization. The institute describes it as the first international publication on using rare-earth catalysts to produce butadiene rubber.

Work on stereospecific polymerization catalyzed by rare-earth complexes won second prize in China’s National Natural Science Award in 1982. Researchers including Bi Jifu, Jiang Liansheng and Zhang Xuequan later ran thousands of scale-up experiments and dozens of pilot trials to develop an industrial process.

A second-generation process led by Bi adds automation and domestically developed technology and equipment. His team tackled precise control of catalyst structure, catalyst preparation, tolerance of different feedstocks and the integration of long-chain branching and functionalization.

The institute says its work progressed from meeting urgent needs of the national economy to supporting national defense modernization. Earlier defense-related work included liquid polysulfide rubber used as a binder for composite solid propellants, which supported China’s “two bombs, one satellite” program.