Nitrile-Butadiene Rubber Sector Needs Specialized Products

By Xia Bin, CNPC Northeast Refining & Chemical Engineering Co., Ltd. Jilin Design Institute

Overcapacity

China commissioned no new nitrile-butadiene rubber (NBR) capacity in 2016. Total capacity remained at 225 kt/a. NBR output was around 126 kt, and the average operating rate of production units was around 56%. Major producers included Lanzhou Petrochemical Co., Ltd., Zhenjiang Nantex Chemical Co., Ltd., (wholly owned by Taiwan Nantex Industry Co., Ltd.), Ningbo Shunze Rubber Co., Ltd., LANXESS-TSRC (Nantong) Chemical Industrial Co., Ltd. and INSA-GPRO (Nanjing) Synthetic Rubber Co., Ltd.
Capacity is already considered to be excessive. Still, plans are made public for construction of new NBR units in the near future. Sinopec and Sibur of Russia plan to jointly construct a 50 kt/a NBR unit. The project is now at the stage of environmental impact assessment, and the unit is expected to be completed and put on stream in the fourth quarter of this year. Anqing Hualan Technology Co., Ltd. plans to construct a 30 kt/a unit for NBR series products.

Consumption

China’s apparent consumption of NBR in 2016 was 206 kt, a YoY drop of 8.0%. The biggest market for NBR is the automobile sector, taking around 60% of total consumption. The industrial rubber product sector is second, accounting for around 22%. With stable development of the automobile industry, output of related automobile components will increase constantly. Demand for NBR in other application sectors, such as electric wires/cables, will also be higher. Annual growth of NBR consumption is expected to be around 3.8% during 2016-2020, and apparent consumption is likely to reach 248 kt in 2020.
China imported 87.9 kt of NBR (excluding latex) in 2016, up 6.5% YoY. Sources were Korea, Russia and France, with Korea providing 49% of the total.

Development of new products emphasized

Profits of NBR producers have shrunk. While improving polymerization feedstock mixes and processes, developing new products and modifying post-treatment methods, producers highlight development of specialized products to enhance competitiveness.
Sinopec uses a unique emulsification system and an oxidation-reduction system to produce NBR with different acrylonitrile contents through copolymerization. The product is very oil-resistant and suitable for use in making oil-resistant rubber products.
PetroChina has developed a way to make NBR by emulsion polymerization, yielding NBR with high micro-gel content. Rubber products made of such NBR have good physical and mechanical properties.
PetroChina and China University of Petroleum (Beijing) jointly developed a catalytic hydrogenation method for hydrogenated NBR products. Beijing University of Chemical Technology developed rhodium catalyst supported by silane coupling agent modified SiO2 and used it as catalyst for selective hydrogenation of NBR. China University of Petroleum researched NBR selective heterogeneous hydrogenation catalysts and ways to make them, as well as related methods for hydrogenation.
Qingdao University of Science & Technology made NBR with high acrylonitrile content and EPDM, and produced NBR rubber stock tolerant of both low and high temperatures. It has also used ethylene-vinyl acetate rubber as compatibilizer for NBR/EPDM rubber stock. Methyl acrylate is added to improve physical and mechanical properties. Carbon nanotubes are added to strengthen the material and improve interfacial bonding. Liquid EPDM is used as softener to improve processing behavior. The rubber stock produced with this feedstock mix has excellent physical properties and good resistance to oils, and tolerates both low and high temperatures. It has a long service life at temperatures of -35℃-150℃.
Sichuan Z River Group Limited has publicized a method to produce liquid NBR with high acrylonitrile content.
Conventional NBR varieties face fierce competition in China. More and more producers and researchers turn attention to specialized products such as hydrogenated NBR (HNBR), powder NBR (PNBR), liquid NBR (LNBR) and carboxylated NBR (XNBR), and even high-end NBR latex, all of which promise higher profits. With ever-increasing requirements on the quality of products in commercial production, paying great attention to unique and high-end materials is surely inevitable.