The Yomiuri Shimbun“Is there some way to keep a wet towel from falling from a child’s forehead?”
An employee’s lament as their child lay suffering from a high fever laid the foundation for the development of the cooling gel sheet. Since its release in 1994 by Kobayashi Pharmaceutical Co., Netsusama Sheet, or Kool Fever, has been providing relief to users around the world.
In the initial stage of the development, company researchers hit a wall trying to achieve a feel and weight similar to a towel. The breakthrough came thanks to an incident at an izakaya restaurant. A slice of konnyaku, a jelly-like food made from konjac potato, dropped onto the hand of a planning supervisor. That’s when the idea hit.
To realize cool and soft feelings, a technique to coat a non-woven fabric with water-retentive gel was adopted. The main problems were then how to make it stay cool longer, and how to keep it from coming off easily. Through about 200 prototypes, the researchers managed to get a product ready to be marketed.
The cooling time was only two hours at first, but was extended to eight hours through improvements in the gel and other means. The sensation of coolness was maintained through the technique of mixing in menthol granules with the gel.
Two years after its introduction, the company began sales in Hong Kong, and later expanded to Singapore and Britain. Currently it is available in about 20 countries, with overseas sales accounting for 56 percent of the total. In 2014, it was also highlighted in Chinese media as one of “the 12 medicinal products you must buy when you go to Japan.”
While originally targeted for those suffering from a fever, many users have made it a part of their everyday lives, having no qualms about slapping one on their foreheads when they are having difficulty sleeping at night or need to concentrate on something.