Sole domestic producer of Open Cell Rubber Sponges
Features washability of a coarse surface texture and low permanent strain
Replaced by polyurethane
The closed cell sponges our company has manufactured since inception is a post-World War II technology. But we understand that the open cell technology was available earlier, at least as early as before the war. While most of the past applications consisted of use inside sofas, the appearance of polyurethane, most notably in dishwashing sponges, became the largest application for closed cell sponge. Most of the material then began to be used to make polyurethane. Closed cell sponge remains in use now in applications that polyurethane cannot serve.
Concrete washing, cushioning in the heels of shoes…
There are two material characteristics that make polyurethane unsuitable for some applications. The first is the course surface texture that gives rise to washability. Although polyurethane is good for washing most household dishes, open cell rubber sponge is used when washing concrete and similar surfaces. The low permanent strain is another reason for use as the material inside the heels of many shoes. You can imagine that if polyurethane were used, it would be destroyed very quickly by the large amount of permanent strain. The sponge used to clean the inside of beer server pipes is also open cell sponge, the utility of which capitalizes on these two characteristics.
Miyahara inherits technology from the sole remaining company
When applications for a material decrease, so does the number of enterprises who manufacture it. While we will spare the background story here, Miyahara Rubber inherited the technology of the sole remaining open cell rubber sponge manufacturer. While it may seem like we are blowing our own trumpet, Miyahara Rubber is the last surviving company who can make open cell rubber sponge. This fact alone is enough to make us unique, but if it can be done, we want to try to utilize closed cell technology in open cells. To mix technologies never before combined and create something new is at the core of who we are.
（Yoshinobu Miyahara, Miyahara Rubber Industry Co., Ltd.）
