The R&D Front Line vol.2 Maki Samitsu


Tackling the challenges of hot melt with pride in our strengths as a Japanese manufacturer

Hot melt adhesive is a type of adhesive that is melted and applied at a heat of around 130°C to 180°C, after which it cools and hardens. The use of these adhesives as alternatives to solvent- and water-based products is growing in markets that require high-speed production. MORESCO is the only Japanese manufacturer of hot melt adhesive for use in the hygiene products field. Maki Samitsu is a MORESCO employee who is involved in the development of hot melt adhesive for hygiene products such as disposable diapers. We asked her about her thoughts on research and development.

Maki Samitsu

Research theme Taking on the challenge of developing hot melt adhesives that are highly functional yet versatile

Hot melt adhesives are used in a variety of fields including hygiene products such as disposable diapers and sanitary napkins, labels on plastic bottles, labels for concealing personal information on postcards, building insulation, and automobile interiors. Disposable diapers are made by gluing together various materials such as non-woven fabric, polyethylene sheets, tissue, and rubber leg gathers using hot melt adhesive. As different performance is required in terms of texture, adhesive strength, holding power, and other characteristics according to which part the adhesive is applied to, a variety of hot-melt adhesives are used. However, despite this variety, customers want to reduce the types of hot melt adhesive they use in order to streamline inventory management and avoid erroneous application. In response to such requests, we conduct research aimed at producing highly functional yet versatile hot melt adhesives by selecting the combination ratio of base polymers※1, tackifiers※2, and softeners※3 used as raw materials, and types of raw materials.

Challenges involved in research Developing products capable of maintaining performance across a wide temperature range

As hot melt adhesives are used for gluing a variety of different materials in a wide range of environments, the products we develop must be capable of withstanding harsh environments. As hot melt adhesives consist of thermoplastic*4 compounds, their main weakness is that they are easily affected by temperature. If we are going to make a hot melt adhesive for use in disposable diapers for the Japanese market, we have to be able to produce a product that will perform the same in a wide range of temperature zones from Hokkaido to Okinawa. To maintain performance in both high and low temperatures, we work to discover the optimal combination ratio and the optimal materials to use. There are many different types of each material, so working out the golden ratio to maximize performance is both a difficult and a fun part of our job.

Distinctiveness A Japanese-style approach to product development that puts the customer first

MORESCO is the only Japanese manufacturer of hot melt adhesive in the hygiene products field. The basic stance of our Hot Melt Adhesives Division is to always strive to see things from the customer's perspective. To ensure that we are able to do this, we ask the customer directly what they want wherever possible and use this information to provide rapid development and detailed service. I think this is a strength that foreign-affiliated manufacturers in Japan lack. For example, we sometimes have development periods of one to two months, or really short turnaround times of only two weeks. To respond to the customer's requirements, we conduct numerous tests using our own proprietary databases and know-how, which enables us to implement improvements and develop products with short turnaround times. With the trend toward lower market prices in recent years, manufacturers have tended to use cheaper materials, leading to hot melt adhesives with strong plastic odors or poor heat stability, but we always try to develop products that will live up to the Japanese reputation for quality.

Problem solving We can’t say no, no matter how hard the challenge or how short the turnaround time

Since joining the company, we have had many problems with material supply limitations, disasters, and other issues. When developing new markets, things keep getting more and more challenging—we'll get a request for more sophisticated performance or an order with a short turnaround time because the customer's schedule for final acceptance testing has already been decided. No matter how hard the job is, we can't say no because we want to deliver what the customer has requested. For this reason, we conduct test after test for as long as we have time, and there have been a few times when we've pulled all-nighters to get a job completed on time. When a customer gives us positive feedback on a product that we've developed after running test after test, it makes us so happy we're lost for words.

Attitude to work If I come across something I don’t understand, I don’t leave it that way

When it comes to research and development, I always ask myself questions like "What can I do for the customer?" and "What would make this product better?" To answer these questions, I'm constantly trying to read between the lines to see what it is that the customer really wants. Another thing that's important, whether it's with regard to the customer or our own company, is to never ignore something you don't understand. If there's something I don't understand, I ask someone or investigate it straight away. I do this because if I don't, I won't improve my skills or grow as a person.

Another thing I do is doubt everything. If I do something successfully, I check repeatedly to see why things worked out the way they did and whether or not I actually understand the situation correctly. This helps me clarify what we can and can't achieve by doing what we've done, which makes it easy to talk to the customer with confidence. My dream is for hot melt that I've developed to be used all over the world. To achieve this I want to improve my knowledge of materials and blending technologies.

*1 Base polymer - A component that determines the properties of a hot melt adhesive. Includes materials such as synthetic rubbers and olefins.
*2 Tackifier - A component that gives glue its stickiness.
*3 Softener - Softeners used include oils and waxes.
*4 Thermoplasticity - The phenomena whereby a solid melts and becomes a liquid when heat is applied.

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vol.2 Hot melt Adhesive Division R&D Department Maki Samitsu

Tackling the challenges of hot melt with pride in our strengths as a Japanese manufacturer
Research theme
Challenges involved in research
Problem solving
Attitude to work