The Story of the Birth of New Products(Isoprenes)

Turning the Oil Crisis to Advantage

Throughout its history, Kuraray has energetically taken on the challenge of replacing limited natural resources by developing and commercializing synthetic alternatives such as rayon, Vinylon synthetic fiber, and man-made leather CLARINO. The fourth target was development of a synthetic version of natural rubber, which was anticipated to become in short supply. Although the company successfully commercialized polyisoprene rubber in 1972, it quickly lost competitiveness as a result of the 1973 oil crisis that occurred shortly after the announced introduction of the new synthetic rubber. An exhaustive effort by the company started to curtail production costs markedly through the introduction of changes to the manufacturing process. The Kuraray R&D team also tenaciously pursued the development of high valueadded products connected to building up the company's isoprene chemicals business, which today boasts high profitability.

Adherence to Kuraray Proprietary Technology

General view of Kashima Plant (1972).

When the company first started to conduct R&D into synthetic rubber around 1960, the greater part of world demand for rubber relied on natural rubber. Natural rubber, however, can only be produced in certain areas of the world, such as Southeast Asia. There was also much concern in those days about how stable the supply of such rubber would be over the long term. Under these circumstances, synthetic rubber producers at the time were very keen to industrialize polyisoprene rubber, which was considered a synthetic version of natural rubber. What encumbered them was the huge investment required to develop the industrial processes necessary to produce isoprene monomers (IPM)(*1), the key component to opening the door to the industrialization of isoprene rubber. Prospects for such commercializaton faced numerous challenges.

Against this background, the company focused its R&D activities on establishing an industrial process for producing IPM at a reasonable cost. Through comparative analysis of the IPM production processes available at the time, the company took the daring step of selecting the two-stage synthesis process(*2)instead of the extraction process(*3)adopted by rival manufacturers. The two-stage synthesis process was sidestepped by competing firms because it was difficult to achieve stable operation and reaction yields were low.

Polyisoprene manufacturing plant in
Kashima Plant (1972).

the company decided to use the two-stage synthesis process because it could economically obtain plenty of C4 fractions(*4)as byproducts during ethylene production. In addition, the selection was backed by the company's firm confidence in the synthesis process using its proprietary technology developed and nurtured over many years.

The technology for this synthesis process was practically completed in 1963. Nevertheless, the company could not jump onto the stage of commercialization immediately because there were still issues the needed to be resolved first, such as the establishment of a suitable distribution system. Under these unavoidable circumstances, the company had to discontinue even relevant R&D activities for a time. Later, growth of the automotive industry spurred correspondingly rapid growth in the synthetic rubber industry, which led to acceleration of the mass production of polyisoprene rubber in the United States. the company's synthesis process technology was now in a prime position to steal back the spotlight.

A pilot plant was built at the Kurashiki Plant in 1967 to complete putting in place the industrialization technology. In parallel, a marketing team was organized in 1968 to conduct further market research and development of promising markets. In April 1972, the mass production of polyisoprene rubber was launched at the company's Kashima Plant at long last.

Standing Alone after All Difficulties

Iroprene chemical aromatics.

Soon after the launch of the company's polyisoprene rubber business, the 1973 oil crisis occurred in October that year causing oil prices to soar and subsequently the prices of raw materials for synthetic rubber to skyrocket. Almost simultaneously, the strong yen resulting from the introduction of the floating rate system against the U.S. dollar, and stagnancy in the natural rubber market added to the difficult situation of the company's polyisoprene rubber business. These triple headwinds, now united together, had a crippling effect on the competitiveness of polyisoprene rubber compared with natural rubber.

Without future prospects in sight, the company's polyisoprene rubber business found itself facing the possibility of complete failure at any moment. The R&D team, who had taken the lead in successfully developing the process, was immeasurably shocked by the situation. In spite of these difficult circumstances, however, the company decided to continue with the business based on a forward-looking assessment of the various possibilities that isoprene presented.

An exhaustive effort was undertaken to curtail production costs at the lowest possible levels, while further R&D activities were conducted to search for new fields of high value-added products.

What the company attempted first was to produce a new product from intermediates generated during the synthesis process. This led to the birth of a special solvent, SOLFIT. Today this solvent business has achieved a great leap of growth. In keeping with the launch of production of SOLFIT, the R&D team changed the IPM production process from the two-stage synthesis process to a new three-stage synthesis process. Although the three-stage IPM production process gave way to the one-stage process developed later, it was a monumental process which would have significant impact upon the production of the major products in the chemicals divisions of the Kuraray Group.

The one-stage isoprene monomer (IPM) synthesis process showed the way how to revive the isoprene chemicals business. The R&D team fortunately lighted upon the formation of a small amount of isoprene monomer (IPM) during liquid phase cracking analysis(*5)of a special alcohol formulation by accident. After extensive research, the R&D team succeeded in developing the one-stage process using isobutene, which enabled the company to achieve a stable process at a reduced cost. Thus, the business finally acquired a firm footing comparable to the extraction process used competing firms.

Although construction of the polyisoprene rubber plant was suspended due to the company's poor business performance in those days, the zeal of the people at the manufacturing site for the project, who took the view of it's either now or never, helped greatly to revitalized it. The one-stage process was completed after many twists and turns, and the new plant started operation early in 1987 thanks to the unceasing and assiduous efforts of the project staff.

Around the same period, the company succeeded in developing a technology to produce isoprenol independently (until then, isoprenol was available only as a byproduct of the threestage IPM manufacturing process). This new technology allowed the company to efficiently develop diols (chemical compounds used as raw materials for polyurethane and resin modifiers), specialty chemicals (functional chemicals), and agricultural chemical intermediates, mentioned later. Since then, the three-stage process has been used to produce SOLFIT and isoprenol until now.

Disadvantages involved in the existing processes were overcome by making certain changes in the IPM process. Combined with the development of new technology that made independent production of isoprenol possible, these technological advances did much to help recuperate the competitiveness of polyisoprene rubber. Moreover, the company could take maximum advantage of the byproducts and intermediates produced during such changes and development. It was not until fifteen years after the first steps that the company's isoprene business could finally come to stand on its own.

Blooming Development of High Value Added Fields

Current polyisoprene production factility at the Kashima Plant.

Keeping pace with efforts to reduce costs through the introduction of new changes in the manufacturing process for polyisoprene rubber, the company also proactively sought to expand its fine chemical businesses and further R&D activities toward rebuilding polymer fields.

The first fine chemical field challenged by the company was the isoprene derivative plant, which was completed in 1977 on the premises of the Kuraray Nakajo Plant. The main products produced at this plant included substances in the new fine chemical fields: aromatics such as linalool (fragrance of lilies) and geraniol (fragrance of rose), and chemical compounds such as isophytol, which is used in the preparation of vitamin E, and squalene often used in cosmetics as a natural base oil.

The development of agricultural chemical intermediates was triggered by the company's interest in the natural insecticide Dalmatian pyrethrum(*6)It was known that pyrethroid, the main insecticide component of Dalmatian pyrethrum, has an isoprene frame in its molecular structure, and much study was taking place on its applications. The use of Dalmatian pyrethrum for agricultural chemical application was not successful because its components decomposed when exposed to the sunlight. A British researcher, however, discovered a component with the same mechanism as that of Dalmatian pyrethrum but which was not affected by sunlight. The Kuraray R&D team investigated the news, and finally succeeded in developing pyrethroid-based agricultural chemical intermediates based on the research results obtained at the Sagami Chemical Research Center(*7). Since then, the company expanded its business activities in various pharmaceutical intermediates.

LIR, liquid isoprene rubber.

In the field of polymers, synthetic rubber became unprofitable, thus causing the company to pursue other possibilities for isoprene polymer R&D to survive. One of the research results was the liquid isoprene rubber (LIR). the company is the sole manufacturer of LIR in the world and the demand for this product is growing even now.

The technology developed for LIR gave rise to the development of successive new materials such as SEPTON (thermoplastic elastomer) and HYBRAR (vibration damping elastomer) in the 1990s. These polymers were designed using technology that allows precise control of the alignment of hundreds of thousands of molecules.

The R&D team continually exchanged information with the production and sales departments to research market needs when the product was developed. For example, the LIR for tire plasticizer application was extremely viscous and difficult to handle because of the large molecular weight of the substance of tens of thousands molecular units. This problem was solved by dividing the LIR into smaller packages bearing in mind the convenience of users.

As a result of these developments, the name polyisoprene rubber disappeared from the company's product list. The current product list is now filled with new products that were unknown just a few years ago.

After much research and toil, the isoprene business has evolved to become one of the principal business divisions of the company that now realizes significant profits. The background of this success is greatly due to the close cooperation among the R&D team who accumulated technologies and know-how step by step, the production engineering team who incorporated such technologies quickly, and the sales team who made strenuous efforts to develop new markets from scratch for these new wide ranging products. The starting point for all these efforts was the Kuraray corporate culture of always pursuing original technologies and products while entirely rejecting copying those of others.

  • *1 A monomer (mono means "one") is a small molecule that can be chemically bonded to other monomers to form a polymer (poly means "many") and thus used as the substrate for polymerization.
  • *2 In the two-stage synthesis process, iroprene can be obtained from isobutene, which is one of C4 fractions produced as a by-product during naphtha cracking. Although this process yields plenty of raw material, it was thought to be far less competitive until the company's success in improving the process.
  • *3 The extraction process is a process in which isoprene is extracted as a byproduct of naphtha cracking. This process requires less investment but the amount of raw material produced is limited.
  • *4 A "fraction" in chemistry is the quantity of each component collected from a given batch of liquid mixture in a separation process in which each component is separated by means of fractional distillation based on the differences in the boiling points of each respective substance. C4 fractions include butadiene, butane, isobutene, and similar chemicals.
  • *5 "Phase" refers to a physically distinctive form of a substance, such as the solid, liquid and gaseous states of ordinary matter. Liquid phase is the liquid state of a substance.
  • *6 Dalmatian pyrethrum is known as a natural source of insecticide that is effective on all insects, including mosquitoes, but is far less toxic to mammals.
  • *7 This laboratory was established through the joint cooperation of several chemical companies, including Kuraray Co., Ltd.