Kyowa Rubber can mold different materials such as harder and softer rubbers within a mold to create a product that has more than one hardness.

The materials are chemically joined so they do not separate or become misaligned. This process is incorporated into Kyowa Rubber’s production line, so they are able to offer this service without expensive surcharges.

One useful application of this is synthetic plastic spiral tube connectors. The outside portion is made from a strong, hard rubber for weather resistance while the inside is made from a softer rubber for bacteria resistance and stopping water.

Kyowa Rubber creates ultra-hard sponge molded products—hard as in rubber hard, not like sponges—that are also extremely precise in dimension and desired hardness.

Their ultra-hard sponge molded products are measured at 90 degrees or higher with a JIS-A hardness meter and have a relative density of 0.40 to 0.65. These products have three special features: hardness, strength and light weight.

Kyowa Rubber minimizes variation in hardness, a factor many companies consider difficult to control in ultra-precise sponge molded products. While the industry generally considers ±5 degrees to be a strict level of tolerance, Kyowa Rubber is proud of their standard of ±2.5 degrees. Because of this high level of control, they have 70 percent of the market share for radio controls, where precision is considered important.