A One-of-a-Kind Polymer Innovation

Nippon Shokubai 's technological strength is its ability to produce numerous unique derivatives from a single core chemical. With "technoamenity" at the heart of their research activities, the passionate work of their researchers continues to contribute to society with their unique technology.

"We feel happy that we can contribute to society with a product that only we could have made."
──K, who created the oxazoline-based crosslinkable polymer (EPOCROS™), was one such researcher.

Research started with the introduction of technology from a major overseas chemical manufacturer

In 1987, a technology licensing proposal was brought to our US office by Dow Chemical, a major American chemical company. The proposal involved the introduction of technology for oxazoline monomers and crosslinkable polymers obtained by polymerizing them.
At the time, our company was selling aziridine crosslinking agents and conducting research on polyoxyethylene oxazoline, so we were focusing on polymers containing oxazoline groups.
Although we had no prior experience in licensing technology from other companies, we decided to introduce basic technology from Dow Chemical as our first licensing-in case, hoping to achieve synergistic effects with our own technology.

Mr. K joined the company at the exact time he made that important decision, and was assigned to the Central Research Institute's Third Research Laboratory, where he was put in charge of the technology introduction project.
After completing his training and being assigned to a research lab, he found a thick pile of English technical documents related to licenses on his desk. He began his research career at our company by creating a Japanese summary of these documents while also conducting emulsion polymerization experiments himself.

This research was divided into two parts: establishing the manufacturing technology for oxazoline monomers, and researching cross-linkable polymers produced by polymerizing them. Neither had been produced industrially before, so the team decided to build their own technology based on Dow Chemical's basic technology.
Establishing the technology to scale up both monomers and polymers was particularly challenging, and the information provided in the materials from Dow Chemical, which they relied on, was insufficient, so Mr. K and his team had to go through a constant process of trial and error every day.

Nevertheless, in 1990, the company improved its own manufacturing technology based on Dow Chemical's basic technology and began production of emulsion-type (EPOCROS™ K series) products. Sales of this K series were successful, with the company gaining large-scale users.

Taking on the challenge of what was considered unconventional, the product was successfully commercialized

The emulsion type (EPOCROS™ K series) was very popular for specific applications, but due to limitations in crosslink density, it was not possible to expand its applications widely.

So in 1993, K and his research team decided to start researching water-soluble polymers, a technology not available in the early stages of their research. However, at the time, it was thought that oxazoline monomers could not be made into aqueous solutions because the oxazoline group hydrolyzes very quickly in water. In fact, they had an opportunity to discuss this research with a researcher overseas, who told them, "Because the hydrolysis rate of oxazoline monomers is so fast, we decided it was impossible and discontinued the project. I think it would be pointless to continue."

However, Mr. K and his colleagues did not give up, believing that there must be something that only they could do, and continued their research. They discovered that once polymerized, the oxazoline group is much less hydrolyzable than in the monomer state, and that the hydrolysis rate of the oxazoline group slows down in a mixed solvent of water and alcohol. Finally, in 1996, they completed the water-soluble EPOCROS™ WS series of products.
"If I hadn't seriously aimed for a solution at that time and had instead decided on the theme through superficial consideration, this new material would never have been born," Mr. K recalls.

Since then, sales of the water-soluble type (EPOCROS™ WS series) have expanded, riding the wave of popularity of water-based polymers against the backdrop of VOC regulations and the establishment of the Product Liability Act.

Achieving increased production and improved quality through manufacturing process change

Our company's EPOCROS™ series includes oxazoline-based cross-linked polystyrene (EPOCROS™ RPS series). This product was initially manufactured using suspension polymerization, a technology introduced from Dow Chemical. However, this had problems such as low productivity and a decline in quality due to the additives used.
So, Mr. K and his team decided to take advantage of the opportunity of being hired by a major user and work on increasing production and stabilizing quality by changing the manufacturing method of the RPS series.

However, because they were trying to convert the manufacturing method while still supplying products using the conventional manufacturing method, the development schedule was extremely tight, and they apparently had hectic days, from establishing the manufacturing formula in the laboratory to pilot testing and then commercial operation.In addition, the specifications required by the customer were very strict, and quality variations due to lot differences made it difficult to get approval, so it was a constant process of trial and error.
However, in 1999, we finally established a new manufacturing method using solution polymerization and began supplying the product to major users.
The timing coincided with a major customer's production increase schedule, and sales of the RPS series began to grow.

Establishment of monomer manufacturing technology, which was the lifeline of the EPOCROS™ business

One of the reasons why our company is the only one in the world that produces oxazoline-based crosslinkable polymers is that we manufacture oxazoline monomers in-house. This is where the efforts of Mr. A's team, another key player in the commercialization of EPOCROS™, came into play. Oxazoline monomers are extremely difficult to handle, including due to their hydrolytic nature. So much so that one of the requirements for licensees from Dow Chemical, the licensee, was that they "possess the technology to handle oxazoline monomers."

Development of manufacturing technology for oxazoline monomers began in 1989, but the technology disclosed by Dow Chemical still had major issues, such as polymerization and decomposition during reactive distillation and the suppression of foaming during the reaction.
In particular, there were concerns raised by in-house researchers that reactive distillation was too difficult. Furthermore, Mr. A and his team were troubled by the phenomenon of heat generation from the oxazoline monomer produced by reactive distillation. After investigating the cause of the heat generation at the lab level, and feeling confident about the reaction at pilot scale, they were shocked when the oxazoline monomer began to heat up.

Nevertheless, Mr. A and his team found the optimal polymerization inhibitor for oxazoline monomer, and repeatedly conducted trial and error to examine solvents and mixers to suppress foaming. Finally, they made it from the pilot plant to a full-scale plant, and completed the oxazoline monomer plant in 1997.

Mr. A looked back on the time with a nostalgic look on his life, saying, "As EPOCROS™ was commercialized and sales expanded, in-house production of oxazoline monomers was an essential requirement. At the time, we worked feverishly from the lab to the pilot plant and on to the actual plant, but if we had had more time, we might have been able to do a better job."

A product that blossomed thanks to the efforts of researchers

Mr. K recalls the development of EPOCROS™ as follows:
"In our case, the key to success was introducing oxazoline groups into the polymer."
Many companies focused on the oxazoline group and developed products, but all low-molecular-weight oxazoline crosslinkers eventually disappeared from the market.
Researchers have sincerely studied the special reactive group known as the oxazoline group, and as a result of their efforts to maximize its capabilities, they have brought the product EPOCROS™ to the world.

Mr. K and his colleagues later won the Kinki Chemical Society's Chemical Technology Award for this achievement.

Our EPOCROS™ contributes to improving performance in a variety of applications, including coatings, adhesives, paints and inks, primers, pigment printing, binders for nonwoven fabrics, tire cords, and thermoplastic resin modification.