Kuraray Co., Ltd. has decided to expand the capacity of the liquid isoprene rubber (LIR) manufacturing facilities of its Kashima Plant (Kamisu-machi, Kashima-gun, Ibaraki Prefecture, Japan) by 1,000 tons per year to 4,600 tons. The new facilities will come on line in July 2004.

Kuraray employed its proprietary polymerization technologies to develop LIR in 1977, and today there are a number of variations of this viscous liquid polyisoprene, including functionalized and copolymer materials. LIR is widely used in rubber products, chiefly tires, and in adhesives. Its primary application is as a reactive plasticizer in natural and synthetic rubbers. Although process oils used in this field usually have a molecular weight in the range of several hundred, Kuraray's LIR has a molecular weight of 30,000 - 50,000, and the Company has exploited this extremely high molecular weight to build a niche market.

The use of LIR in natural and synthetic rubbers decreases their viscosity without degrading their mechanical characteristics, which enhances their workability and therefore productivity. For these reasons LIR demand is rising briskly in Asia, and particularly in China, where tire production is expanding. Demand for LIR as a functional additive in the precision molding field, which is pushing forward with performance enhancement of many rubber machinery parts, is also increasing.

The worldwide trend away from the use of organic solvents is bringing increased demand for LIR as a non-solvent adhesive. Non-solvent applications include use as a functionalized adhesive for bonding rubber to textiles and metals. LIR is also used as a raw material in UV cure adhesives.

These factors are expected to bring 10-20% expansion in demand for LIR, and Kuraray is already studying further expansion of capacity. While matching its R&D to user requirements, the Company will continue to create new demand for LIR, and will strengthen and expand its LIR operations as they come to play a greater role in its elastomer business.

Overview of Plant Expansion

Location Kuraray's Kashima Plant (Kamisu-machi, Kashima-gun, Ibaraki Prefecture;
General Manager and Executive Officer, Manabu Kusano)
Production capacity
Present 3,600 tons per year
Expansion 1,000 tons per year
Total 4,600 tons per year
Scheduled startup of
expanded facilities
July 2004
Capital investment Approximately ¥400 million