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The Potential and Future of "buntA," a Made-in-Japan AIR Rubber Brand
Since its founding in 1948, a factory has been supporting the feet of people in Japan as a manufacturer of shoe outsole and insole materials. From this factory comes the rubber brand buntA. Its uniquely formulated AIR rubber is a material that excels in both function and safety.
"buntA" offers a variety of products that use this AIR rubber, with its sandals proving to be a huge hit. So, what exactly is "buntA" rubber all about? We had a chat with Buntaro Higashida, president of Fuji Koatsu Co., Ltd. and the producer of buntA.
The Closed-Cell Foam Rubber Technology Born in Kobe
"The story of closed-cell foam rubber begins in 1951, when it was first developed in the Nagata district of Kobe. It took the form of beach sandals, making its way through Hawaii and then to the rest of the world.Fuji Koatsu Co., Ltd., the parent company of Fuji Koatsu Products Co., Ltd. which develops buntA, has been making this closed-cell foam rubber—which we call AIR rubber—since our founding. Actually, when I took over the family business, I was completely unaware that this closed-cell foam rubber originated in Nagata, Kobe.
I was touring manufacturers in Europe, China, and Southeast Asia to get a sense of our rubber's quality and identify its strengths and weaknesses. During this time, I discovered our strength was in foam materials. After some research, I uncovered the fact that Nagata, Kobe was the true birthplace of closed-cell foam rubber."
The 2010 development of "Marshmallow," a rubber designed specifically for walking, would later lead to the launch of "buntA."
"Our research into materials began with the desire to develop a new insole. With previous insoles, you had to choose between a low-rebound material that absorbs shock or a high-rebound material that bounces back.
However, walking is a continuous cycle of 'landing' and 'pushing off.' You need shock absorption when you land, and you need rebound to take the next step. I began to question the status quo, where you could only choose one, even though both are essential elements of walking.
Through dedicated research, we developed 'Marshmallow,' a single material that successfully combines the contradictory functions of low rebound for shock absorption and high rebound to assist the next step."
Marshmallow was adopted as a material for medical insoles at medical institutions in Kobe, where it earned the nickname "magic rubber." This reputation led to the establishment of Kobe Sogu Seisakusho Co., Ltd. to manufacture custom-made medical insoles.
Then, to leverage our long-standing rubber manufacturing technology and the knowledge we gained from the medical field to give back to the wider community, we founded Fuji Koatsu Products Co., Ltd. In 2020, the brand "buntA" kicked off, centered around the "waraji sandal" designed to promote health from the feet up.
What Exactly is "buntA's" AIR Rubber?
"buntA's" AIR rubber is a blend of various synthetic and natural rubbers with EVA (ethylene-vinyl acetate). It compensates for EVA's lack of elasticity with rubber and for rubber's low weather and durability resistance with EVA, maximizing the strengths of both. It boasts five major features:・Combines both high-rebound and low-rebound (shock absorption) properties
・Excellent lightness, durability, and water resistance
・Superior cushioning for comfort, even during prolonged use
・In addition to being antibacterial, it can be washed with detergent to keep it constantly clean
・Utilizes an eco-friendly manufacturing process
What's more, "buntA's" lineup of products are crafted from four types of materials: Marshmallow, Mochees, Castella, and Cream.
"Marshmallow is our most premium material, and it's also used in medical orthotics. Mochees was developed for a wider range of applications; while having flexibility like Marshmallow, it also boasts excellent durability and weather resistance.
Castella is the lightest material in the buntA rubber family, featuring the largest air cells. It excels in lightness and shock absorption, and also has the special characteristic of not allowing water or dirt to penetrate inside. Cream is a material engineered for ultimate softness. Its touch, true to its name, is as smooth as cream."
Crafting a Diverse Lineup of Products, Starting with Sandals
"buntA" offers a lineup of products including hakimono (footwear), headlined by its flagship "waraji sandal"; shikimono (mats and floor coverings), such as yoga mats; and tsukurimono (crafted items), like bags. Each product features the perfect type of rubber for its purpose—for instance, 'cream' for their room shoes and 'mocheese' for their yoga mats. Harnessing their unique rubber development prowess and technical skill to create finished goods, buntA is taking their Kobe-born AIR rubber to the global stage. The journey of buntA, a 'Made in Japan' rubber brand, is just getting started.
PROFILE
Buntaro Higashida
President & CEO, Fuji Koatsu Co., Ltd.
Producer, buntA
After graduating from the Faculty of Economics at Konan University and working at Fuji Xerox (now FUJIFILM Business Innovation Corp.), Higashida joined the family business, Fuji Koatsu Co., Ltd. In 2014, following the development of 'marshmallow'—a proprietary material combining high rebound and shock absorption—he founded Kobe Sogu Seisakusho Co., Ltd. There, he developed the globally patented medical insole, 'mysole.' In 2019, he established Fuji Koatsu Products Co., Ltd., launching the rubber brand 'buntA' the next year. The brand merges the company's proprietary closed-cell foam rubber technology with the mysole method. Today, he has built an integrated production system that spans from raw materials to finished products, and he continues to explore new possibilities across various fields for the global market.
Text by Fumihito Kouzu
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