By Xiao Ming
Thanks to the characteristics of excellent wear resistance, cold resistance, low heat generation, wet skid resistance, high resilience and fast vulcanization speed, solution polymerized styrene-butadiene rubber (SSBR) has a wide range of applications in the tire industry, especially in the high performance tires, such as green tires, anti-skid tires, super lightweight tires and others. In addition, SSBR can also be used to make raincoats, felt cloth, windbreakers, air mattresses and sponge materials, etc., with a broad development and utilization prospect.
The research and development of SSBR in China began in the 1970s, and after years of development, its production capacity has been greatly developed. As of the end of September 2022, there are six SSBR manufacturers in China, with a total production capacity of 377 000 t/a.
In 2022, China's SSBR production enterprises mainly are state-owned enterprises and joint ventures, among which the production capacity of state-owned enterprises is 247 000 t/a, accounting for about 65.52% of the total production capacity. The production units are mainly concentrated in enterprises affiliated to Sinopec Group Corporation and China National Petroleum Corporation. Among them, the production capacity of Sinopec is 127 000 t/a, accounting for about 33.69% of the total production capacity, and the manufacturers include Sinopec Beijing Yanshan Petrochemical Co., Ltd. (with a production capacity of 30 000 t/a), Sinopec Shanghai Gaoqiao Petrochemical Co., Ltd. (with a production capacity of 67 000 t/a) and Sinopec Baling Petrochemical Co., Ltd. (with a production capacity of 30 000 t/a). The production capacity of China National Petroleum Corporation is 120 000 t/a, accounting for about 31.83%, and the manufacturer includes PetroChina Dushanzi Petrochemical Co., Ltd. (with a production capacity of 120 000 t/a). The production capacity of the joint ventures is 130 000 t/a, accounting for about 34.48% of the total production capacity, and the manufacturers include Zhenjiang Chimei Chemical Co., Ltd. (with a production capacity of 80 000 t/a) and Liaoning North Dynasol Synthetic Rubber Co., Ltd. (with a production capacity of 5.0 t/a).
In 2022, China's SSBR production units are mainly concentrated in Northwest China, Central China, North China, East China and Northeast China, of which East China is the largest production area with a production capacity of 147 000 t/a, accounting for about 38.99% of the total production capacity, followed by Northwest China, with a production capacity of 120 000 t/a, accounting for about 31.83% of the total production capacity. In addition, the production capacity in North China is 30 000 t/a, accounting for about 7.96% of the total production capacity; the production capacity in Northeast China is 50 000 t/a, accounting for about 13.26% of the total; the production capacity in Central China is 30 000 t/a, accounting for about 7.96% of the total. PetroChina Dushanzi Petrochemical Co., Ltd. is the largest SSBR manufacturer in China, with a production capacity of 120 000 t/a, accounting for about 31.83% of the total production capacity, followed by Zhenjiang Chimei Chemical Co., Ltd., with a production capacity of 80 000 t/a, accounting for about 21.22% of the total production capacity.
Chinese SSBR manufacturers adopt a combined technology of domestic technology and imported technology. Among them, Liaoning North Dynasol Synthetic Rubber Co., Ltd. adopts the technology of Dynasol Group from Spain, Sinopec Shanghai Gaoqiao Petrochemical Co., Ltd. adopts the technology of Asahi Kasei Corporation from Japan. Zhenjiang Chimei Chemical Co., Ltd. adopts the technology of Chimei from Taiwan, China. One 60 000 t/a unit of China Petroleum Dushanzi Petrochemical Co., Ltd. adopts the technology of Eni from Italy, and the other 60 000 t/a unit adopts the self-developed technology by China National Petroleum Corporation. Sinopec Beijing Yanshan Petrochemical Co., Ltd. and Sinopec Baling Petrochemical Co., Ltd. adopt the self-developed technology by China National Petroleum Corporation.
New technology development
While building new production units, Lanzhou Chemical Industry Research Center of PetroChina Petrochemical Research Institute independently developed the "120 000 t/a SSBR process package", marking that PetroChina has mastered mature high-performance SSBR complete sets of technology in synthetic rubber field. In August 2021, the functionalized SSBR product jointly developed by China Petroleum and Petrochemical Research Institute, Tongji University and Dalian University of Technology completed the industrial test in Dushanzi Petrochemical Co., Ltd. and passed the 72-hour on-site assessment organized by the China Petroleum and Chemical Industry Federation. After years of technical research, the domestic high-end new tire tread rubber with independent intellectual property rights was launched.
PetroChina Lanzhou Chemical Industry Research Center has developed star-branched SIBR integrated rubber, completed the pilot test research, and completed the performance evaluation of tire table rubber for the pilot test product.
In terms of new product development, many SSBR manufacturers target the oil-extended rubber market. For example, Dushanzi Petrochemical Co., Ltd. mainly develops and promotes oil-extended high-vinyl SSBR products in domestic market. Sinopec Beijing Research Institute of Chemical Industry Yanshan Branch and Beijing Yanshan Petrochemical Rubber & Plastic Chemical Co., Ltd. jointly developed SSBR2506, 2535E, 2636 and other series of products. In addition, another developing focus lies in the functionalized SSBR products. Dushanzi Petrochemical Co., Ltd. adopts anionic polymerization technology and continuous production process, and develops oil-filled linear random high styrene and medium vinyl structure SSBR 3840S products, which are mainly used for racing tires. Moreover, Dushanzi Petrochemical also adopts anionic polymerization technology and continuous production technology, and develops oil-filled linear random low styrene, medium vinyl structure SSBR 1540S products, which are mainly used for winter tires.
Consumption status and development prospects
In recent years, the apparent consumption of SSBR in China has been increasing year by year. The apparent consumption in 2017 was 124 000 tons, and 176 000 tons in 2021, a year-on-year increase of about 16.56%. The average annual growth rate of apparent consumption from 2017 to 2021 was about 9.10%. The self-sufficiency rate of corresponding products was 75.1% in 2017 and 81.2% in 2021.
China's SSBR is mainly used in the tire production, plastic modification and shoemaking, among which 78% is used in the tire industry. The consumption of tire production accounts for about 80.0% of the total SSBR consumption, the plastic modification accounts for about 14.0%, and other aspects such as shoemaking account for about 6.0%. Since East China and South China are the main production bases of tire, shoemaking and plastic modification in China, SSBR consumption is also mainly concentrated in these two regions, and the demand for SSBR in East China accounts for about 83.0% of the total consumption, and South China accounts for about 7.0%.
With the rapid development of China's automobile industry and highways, the popularity of radial tires, and especially under the background of the "dual carbon" and "dual control" policies, new energy-saving radial tires have experienced rapid development, and correspondingly higher requirements have been put forward for the rubber used for tires. SSBR has good wet skid resistance and low rolling resistance, which can significantly improve the tire's wet skid resistance. Therefore, its consumption in the tire industry will keep growing steadily, and coupled with other applications, it is expected that China's demand for SSBR will reach 280 000-300 000 tons in 2026.
Development trends and suggestions
1. Future development trend
(1) In the next few years, China will have several SSBR units coming on stream including Zhejiang Petrochemical Co., Ltd. 60 000 t/a unit, and PetroChina Guangxi Petrochemical Co., Ltd. 120 000 t/a unit, etc., and the production capacity will continue to increase. If these projects can be implemented as scheduled, it is estimated that by 2026, China's SSBR production capacity will reach 557 000 t/a, and the situation of excess production capacity may appear.
(2) With the completion and commissioning of new units, the import volume of SSBR in China will gradually decrease, but some high-end brand products still need to be imported. In the meantime, with the increase of domestic supply, the export volume will gradually increase in the future.
(3) Radial tire has become the mainstream tire products in the world. SSBR is the best and indispensable rubber for manufacturing high-performance green tires, and it is also the must-selected rubber for radial tire. Functionalized SSBR will become the mainstream of future development.
(4) Continuous polymerization of SSBR has the advantages of large production scale, high efficiency, low material consumption and energy consumption, and is the future development direction.
2. Development suggestions
(1) With the completion and commissioning of new units, the capacity of SSBR in China has already been excess. In the future, new or expanded units should be cautious, and various factors should be considered comprehensively such as technology source and advancement, source of raw material, product structure, and downstream demand to avoid the waste of human, material and financial resources, and avoid blind competition among domestic enterprises.
(2) Speed up technology development and improve the ability to regulate vinyl content and styrene content in the SSBR polymerization process; develop a new type of high-efficiency initiation system with simple synthesis process, easy-to-obtain raw materials, low price and functionality; develop a new type of regulator system with high-efficiency, temperature resistance and without affecting subsequent reactions; develop functionalization and various modification technologies; develop a continuous SSBR polymerization process with independent intellectual property rights on the basis of further improving the batch polymerization process to improve China's SSBR overall production technology level.
(3) Reduce the cost of SSBR production and use. All production enterprises should continuously optimize the production process, reduce energy consumption and material consumption, and reduce the production cost of SSBR through technological progress. In addition, it should develop new formulations with low usage and excellent performance and improve the existing formulations to reduce the use cost and meet actual needs.
(4) Adjust the product structure and accelerate the research and development of new SSBR varieties. At present, China's SSBR products are mainly the first generation and the second generation, and there is long distance to catch up with the foreign countries. In the future, we should give full play to the advantages of a wide range of SSBR structure adjustments, and develop new products and grades of SSBR according to the individual needs of different application fields, the requirements of processing and application formulas, and flexible use of polymer design and optimization modification methods, such as filling eco-friendly oil SSBR, block random SSBR, SSBR with trapezoidal gradient in unit composition and structure, partially hydrogenated SSBR, SSBR with gradient 1,2-structure, ternary integrated rubber SIBR, and SSBRs with different vinyl content and bound styrene content, various (single-end, double-end modification) end group modified SSBR products, etc., to expand the variety and grade of SSBR to meet the needs of different users.
(5) Strengthen the connection of SSBR scientific research, production and users, set up SSBR production, sales, research and application development teams for different applications and end users, integrate the strength of research institutions, SSBR manufacturers and tire manufacturers, and jointly complete the development and application of new SSBR products and new grades. Strengthen cooperation with downstream users to develop targeted and applicable products. Provide customers with not only the products, but also the technical support.