SBC: Consumption Structure Is Changing with Emergence of Alternative Materials - China Reports

By Wang Yuying, Xu Zhonglin and Liu Yan

Styrene thermoplastic elastomer (SBC) is a thermoplastic elastomer (TPE) with the largest output and is also one of the most widely used TPEs. The domestic SBC capacity structure has changed amid increasing investments from transnational companies and stronger China-based private producers. The emergence of new alternative materials has squeezed the room for the growth of the application of SBC.
SBC is mainly divided into four categories - styrene butadiene styrene block copolymer (SBS), hydrogenated styrene butadiene styrene block copolymer (SEBS), styrene isoprene styrene block copolymer (SIS) and hydrogenated styrene isoprene styrene block copolymer (SEPS). SEBS and SEPS are hydrogenated from SBS and SIS respectively, excluding unsaturated double bond, so they have excellent heat resistance, oxygen resistance, aging resistance and UV resistance.

Higher proportion of private companies

There were about 17 SBC producers in China in 2019, among which, 15 ones produced SBS, 9 produced SIS and 4 produced SEBS. The total capacity reached 1.55 million t/a. Table 1 shows the existing producers and SBC grades in China.

Domestic SEBS producers and their capacity in 2019 are as follows: Baling Petrochemical’s at 40 kt/a, Ningbo Oretel Polymer’s at 20 kt/a, LEE CHANG YUNG CHEMICAL (Huizhou) Rubber’s at 30 kt/a, TSRC (Nantong) Industry Co., Ltd’s at 35 kt/a. The total capacity hit 125 kt/a.
The domestic SBC capacity structure has changed with increasing investments from transnational companies and continuous growth of China-based private producers. At present, the capacity of state-owned producers accounts for 34.2% of China's total, that of foreign-funded producers accounts for 32.9%, and that of domestic private producers takes up 32.9%.

Consumption fields in change

   SBC is an elastic material between rubber and plastic. About 1/3 of the products are used in rubber industry because they have both the processing characteristics of plastics and the physical and mechanical properties of rubber. The rest are largely used in non-rubber industry, with the majority applied as polymer modification, adhesives and sealants, and the remaining as additives of ink and coating.
   China's SBC consumption was 758 kt in 2014, and it was estimated at 900 kt in 2019, with an average annual growth rate of about 3.4%. The consumption structure in 2019 was: 28% for shoe glue, 36% for asphalt modification, 17% for plastic modification, 15% for adhesive and 4% for others. Asphalt modification has replaced shoe glue to become the largest consumer of SBC.
   1. SBS
   SBS has excellent processability and it can be widely used in downstream sectors such as shoe making, road asphalt modification and waterproof membrane. Shoe industry used to be the biggest consumer of SBS in China and up to 50% of SBS was used in the shoe industry before 2008. In recent years, however, a big number of shoe makers have migrated to Southeast Asia and South Asia, greatly hampering the application of SBS in Chinese shoe materials field. In addition, advanced elastomer materials such as polyurethane thermoplastic elastomer (TPU), ethylene vinyl acetate copolymer (EVA) and olefin elastomer (POE) are more and more applied in shoe material production, and the market share of SBS in the shoe material market is facing great challenges.

   Asphalt modification has been growing fast in recent years and has become the largest downstream consumer of SBS. Higher requirements on road construction during the 13th five-year plan period and the further implementation of “One Belt, One Road” economic policy have promoted the development of Chinese road construction significantly. At the same time, the construction process of mass transit rail projects in the first and second-tier cities has been accelerated.
   With the acceleration of urbanization, building insulation and waterproofing has become a new growth point, bringing new developing opportunities to the waterproofing membrane industry. In the context, SBS will have great development in the field in the long term.
   2. SEBS
   SEBS is an elastomer with high performance and high added-value, which has excellent weather resistance, heat resistance and wear resistance. Although SEBS accounts for a small proportion in the consumption of styrene TPEs, the consumption of SEBS in the medical market is growing rapidly due to its unique properties.
   3. SIS
   With excellent corrugated sealing property and high-temperature retentivity, SIS is mainly used in the production of pressure-sensitive adhesive and hot melt adhesive that are applied in fields such as health care, electrical insulation, packaging, protection and shelter, sign, bonding and fixation, and interlayer bonding of composite bags. In particular, the hot-melt and pressure-sensitive adhesive market is developing fast as the grades have a wide range of applications.
   4. SEPS
   As a high-performance polymer material, SEPS is mainly used as factice of optical fiber and cable, lubricant viscosity index improver, and elastomer for sports equipment and protective equipment. It is an irreplaceable material in the optical fiber and cable sector, a high-cost-performance lubricant viscosity index improver and a key elastomer with high resilience or low hardness. It is expected to have a great potential, as the consumption of SEPS in China is estimated to reach 50 kt in the next five years.

The emergence of alternatives restricts SBC application

   SBC is a heat-labile material. SBS and SIS cannot be used at above 80℃. SEBS and SEPS can stand a little higher temperature, but the prices are hefty. Therefore, the application of SBC is greatly restricted.
   For example, the application room of SBS in the shoe-making sector is being squeezed by ethylene vinyl acetate elastomer (EVA) and polyurethane elastomer (PU), as EVA is soft, fracture-resistant, cheap and versatile, and PU is more wear-resistant and has higher performance. The proportion of SBS is likely to decrease in the future.
   SBS is losing its edge on the heels of the emergence and development of new materials. In addition, SBS modified asphalt is hit by lower-priced waste rubber powder (WRP) and recycled rubber.
   As adhesive and sealant, SIS has had important presence in the market, but the consumption and proportion of SIS are limited. In the meanwhile, it is facing challenges from natural rubber (NR), butyl rubber (IIR) and polyisobutene (PIB).