Demand of SIS Increases Stably

By Zhou Liaoyuan

  1. Supply deficit of SIS

SIS (styrene-isoprene-styrene block copolymer) can be used to
produce adhesives, coatings and plastic modifiers. The
production capacity of SIS in the world is around 350 thousand
t/a today and the output is around 300 thousand tons, accounting
for 15% - 20% of the total output of styrene thermoplastic
elastomers.
   The research and development of SIS in China was started in
the 1980s. The Research Institute of Sinopec Beijing Yanhua
Petrochemical Company Ltd., the Research Institute of CNPC
Lanzhou Petrochemical Company Ltd. and Sinopec Yangzi
Petrochemical Company Ltd. all participated in the research and
development of SIS. Sinopec Baling Petrochemical Company Ltd.
completed SIS lab tests in 1994 and successfully developed and
produced SIS-1200, SIS-1204, SIS-1105 and SIS-4104 in 1996. With
the supply increase and market change of isoprene, Sinopec
Baling Petrochemical Company Ltd. also developed commercialized
products such as SIS-1106, SIS-1188,SIS-1209, SIS-1224,
SIS-1225 and SIS-1226 and specialty and fine products such as
SIS for PVC flooring adhesives and SIS for films. Besides,
Sinopec Baling Petrochemical Company Ltd. has actively
conducted application research, provided supports to the
application dissemination of SIS products and promoted the rapid
growth of the domestic SIS market.
   As most C5 products have not yet been utilized in China, the
production of SIS is restricted and the supply of SIS is
inadequate. Only Sinopec Shanghai Petrochemical Company Ltd.
produced small quantities of isoprene in China before 2005. The
output of SIS in Sinopec Baling Petrochemical Company Ltd. could
only be maintained at around 5 thousand tons a year. Downstream
users had to use substitutes such as SBS
(styrene-butadiene-styrene block copolymer) or import
high-priced SIS from abroad. The import amount of SIS was around
20 thousand tons a year. Major suppliers include China Synthesis
Rubber Corp. of Taiwan province, Kraton Polymers and Dexco
Polymers of the United States, JSR and Zeon of Japan and Eni of
Italy. C5 separation units in Shandong Yuhuang Chemical Co., Ltd.
and Qilu Luhua Chemical Co., Ltd. were started production in 2005
and the local supply of isoprene was increased. The output of
SIS in Sinopec Baling Petrochemical Company Ltd. was close to
10 thousand tons in 2006. Based on the supply of isoprene, the
output of SIS in the company is expected to reach 15 thousand
tons in 2007.

  2. Bright market prospect

Hot-melt pressure-sensitive adhesives are developing fast in
China. They are extensively used in packaging, automobile,
electronic, construction, medical care, sanitary, aviation and
space flight sectors. According to statistics, the output of
pressure-sensitive adhesive tapes in China already holds the
third place in the world, only next to the United States and Japan.
Most of hot-melt pressure-sensitive adhesives in China are used
in disposable sanitary materials. The application rate of such
sanitary materials is not yet 1% in China but has already reached
90% in the United States and also 64% in Taiwan province. The
demand for hot-melt pressure-sensitive adhesives and SIS
substrates is very large in China and SIS has a bright market
prospect.
   It is reported that the consumption for SBS and SIS in the
adhesive sector is more than 60 thousand tons a year. SIS-based
adhesives have advantage in environmental friendly, short
process flow in processing and excellent property of products.
Their market share in the adhesive sector will increase. Through
research and innovation for more than a decade, both the
production technology and the product quality of SIS in Sinopec
Baling Petrochemical Company Ltd. have reached the world
advanced level and provided a technical guarantee for the
development of the SIS sector.

  3. Bottleneck in isoprene supply

Isoprene is the fraction with the highest utilization value in
C5 products. It is mainly used in the synthesis of SIS, isoprene
rubber and butyl rubber and also in organic synthesis. In the
consumption composition of isoprene in the world, the
consumption in the butyl rubber production is quite small, only
accounting for around 4% of the total. The production of isoprene
rubber and SIS use isoprene as major raw material and the
consumption each accounts for more than 40% of the total. As
China still has no commercial production units of isoprene
rubber, the major application sector for isoprene is SIS.
   The ethylene industry in China is developing fast. The amount
of C5 resources as byproducts has increased rapidly. C5
separation technology is also being improved. The supply amount
of isoprene will therefore grow constantly. The output of
ethylene in China reached 8.765 million tons in 2006 and the
output of isoprene should be 1.05 million tons. According to the
long-term development program for the ethylene industry, the
production capacity of ethylene in China will be more than 15.5
million t/a in 2010 and the amount of C5 fractions should
therefore be more than 1.8 million tons. In this way the amount
of isoprene in byproducts of the ethylene production will reach
around 300 thousand tons and sufficient raw material can be
provided for the development of the SIS sector.