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Cooling Gel Sheet (KOBAYASHI Pharmaceutical Co., Ltd.)

Under the motto of "You make a wish, and we make it happen," Kobayashi Pharmaceutical has identified unprecedented needs and created new products and markets.

As an example, this article introduces how the company invented the cooling gel sheet.

(Fig.1) Cooling Gel Sheet
(Fig.1) Cooling Gel Sheet

Research and development started when an employee faced a problem
(Impetus and recognized issues)

Research and development of the cooling gel sheet started from an employee's comment: "It's a nuisance when I have a fever and the wet towel slips off my forehead while I'm asleep."

The company immediately surveyed its employees and consumers and found many people experiencing the same problem.

The company additionally surveyed what kind of product consumers wanted to purchase and identified three needs: ready availability without having to wet the towel, no slipping or falling out of place, and remaining cool for a long time.

As a result, they started to develop a thin product that adheres to the forehead in order to break the fever. This development began more than 25 years ago.

As target users, the company focused especially on children and their parents. When a child suffers from a fever, the parents worry. The company invented the cooling gel sheet with the hope that it would help mitigate the family's suffering even a little.

Cooling gel sheet
(Details of the invention and design)

The cooling gel sheet consists of a gel that contains a large amount of moisture and an adhesive sheet to attach the gel to the user’s forehead.

The moisture in this gel lowers skin temperature by -2℃ for about eight hours through evaporation caused by the heat of the forehead due to fever. The developers found a way to successfully maintain a cool feeling for many hours by finding the right amount of moisture for the gel and combining it with menthol capsules.

They also pursued the optimal adhesion and invented a sheet that does not fall off during use yet is easy to remove when desired.

(Fig.2) Evaporation of the moisture in the gel
(Fig.2) Evaporation of the moisture in the gel

(Fig.3) Menthol capsules
(Fig.3) Menthol capsules

Even though the product was developed for children with fevers, this cooling gel sheet is now available in several variations targeting adults and babies. Although Kobayashi Pharmaceutical initially assumed that the product would sell well in winter when children tend to develop fevers, it enjoys a high sales volume in summer as well. After a survey revealed that the product is used as a defense against the heat, the company began enthusiastically promoting that aspect, too. The product now sells better in summer than in winter.

Konjac Sashimi inspired the cooling method
(Travails until completion)

After developing a solid product concept, the developers continued to consider the cooling method.

After racking their brains for two months to come up with a good idea, the eureka moment arrived at an izakaya restaurant that three developers visited.

While they were talking, a piece of Konjac Sashimi accidentally fell onto the arm of one of them, causing him to feel a fresh and cool sensation. At this moment, they had the idea of using cool gel.

They then looked for a water-retentive gel and attached it to a skin-friendly nonwoven adhesive sheet to create the basic structure.

(Fig.4) A piece of Konjac Sashimi accidentally fell onto the arm
(Fig.4) A piece of Konjac Sashimi accidentally fell onto the arm

However, there was still a long way to go. The development team had to realize an easy-to-use size for children, comfortable adhesion to keep the sheet attached even if the user has a fever and sweats, and the right amount of moisture in the gel to maintain the cooling effect.

First, they surveyed their own children’s foreheads to gather data in order to determine an easy-to-use size for children. Next, they considered a stable thickness to reliably cool down the fever, taking into account the weight and the feel against the skin in order to eliminate the strain and uncomfortable feeling of the sheet adhering to the forehead. After repeated experiments in which about 30 employees sweated in an experimental laboratory at an ambient temperature of 40℃ with a humidity of 75%, they finally discovered the optimal adhesion and amount of moisture for the gel. They had tried over 200 experimental patterns. The experiment was physically demanding and more difficult than expected.

All employees submit ideas monthly

"You make a wish, and we make it happen" means "creating unprecedented new products."

What is special about Kobayashi Pharmaceutical is that all employees engage in product development. Every employee generates and submits ideas for new products every month. Of the roughly 40,000 ideas submitted annually, 10 to 20 are commercialized. Ideas are not limited to those of the development department; one idea that was adopted and commercialized came from an employee in the accounting department.

Although coming up with ideas sounds difficult, the company explains that if you get used to submitting at least one new product idea a month, you can train your brain and become more sensitive to problems in daily life.

What is more worthy of note is that the company assesses all 40,000 ideas submitted annually one by one and lets the inventors know if they decide to adopt their ideas.

People would gradually lose motivation if they received no reaction even though they submitted ideas every month. By contrast, receiving a sincere assessment motivates them and causes them to want to consider new ideas. This is likely to be the secret as to why Kobayashi Pharmaceutical continues to create new unique products.

Prioritizing simplicity in naming
(How industrial property rights contributed to the invention)

When promoting a completely new product, it is important to have consumers instantly recognize that the product will solve a heretofore unrecognized problem. Pursuing this simplicity, Kobayashi Pharmaceutical has many products with unique names such as Netsusama Sheet (a coinage for the cooling gel sheet that combines netsusamashi (antipyretic) and sheet) and Itoyoji (a coinage for their floss pick that combines ito (floss) and yoji (pick)). These have become familiar to Japanese people through TV commercials and other advertising.

Kobayashi Pharmaceutical is a company based in Osaka, the center of comedy in Japan. However, these names are not plays on words but rather the results of their efforts to express the products in an easy-to-understand way. At product naming meetings, everyone is very serious, and no laughter is heard.

Their accomplishments in creating unique names have been highly evaluated; Kobayashi Pharmaceutical received the FY2020 Award from the Commissioner of the Japan Patent Office to recognize them as contributors to the intellectual property rights system as a company that leverages trademarks.

(Fig.5) Received the FY2020 Award from the Commissioner of the JPO
(Fig.5) Received the FY2020 Award from the Commissioner of the JPO

Becoming too famous can cause problems

Kobayashi Pharmaceutical trademarks the product name of each new product it develops. A trademark is a mark that identifies the product source. Third parties are not allowed to use registered trademarks without permission.

If an unprecedented product sells well, over time the product name may come to be commonly used. For example, "escalator" used to be a registered trademark of an American company.

As Netsusama Sheet similarly tends to be mistaken as a product category name, the company makes efforts to prevent it from falling into common use. For example, if they find a case in which the product name is used as if it were a common name, they inform the user that it is a registered trademark and ask them to change the description. This is because if Netsusama Sheet falls into common use, the trademark rights will lose their effect even though it is a registered trademark of Kobayashi Pharmaceutical.

What is special about Kobayashi Pharmaceutical, the innovator?

Kobayashi Pharmaceutical is promoting the "big fish in a small pond" strategy to create innovative products.

You can catch big fish in a small pond that has fewer anglers, whereas you can only catch little fish in a large pond that has many anglers. The size of the pond represents the market size, while the fish represent profits.

This strategy is intended to create a new pond (market) and get big fish (profits)—in other words, to develop new one-of-a-kind products rather than to rely on products that many competitors can also produce.

(Fig.6) The
(Fig.6) The "big fish in a small pond" strategy

However, even if you create a new pond through your diligent effort, once people know that there are big fish, many anglers will come. So, you cannot dominate the pond.

Patents and design rights serve as measures to fence in the pond so that others cannot enter.

Kobayashi Pharmaceutical also considered applying for patents and other rights but concluded that in the case of Netsusama Sheet, they could not completely fence in the pond with such rights.

Therefore, Kobayashi Pharmaceutical decided to differentiate themselves from their competitors by protecting the distinctive features of their products with patents and other rights so that other companies cannot imitate them.

For Netsusama Sheet, the company employs a design right to protect the portion that contains menthol capsules, which maintain a cool feeling.

Meanwhile, the entry of competitors into a new market may provide benefits. An increase in the number of competing products invigorates the overall market.

Kobayashi Pharmaceutical has a policy of creating new markets by being the only company in that market and remaining the number one company even after competitors enter the market.

To achieve this, products must continue to evolve. Netsusama Sheet now has higher functionality; for example, today the product can remain cool for eight hours compared to two hours when it was initially developed.

Creating a new practice when one has a fever
(Effects of the invention)

More than 25 years have passed since the launch of Netsusama Sheet, and its cumulative sales volume exceeds 400 million.

In the past, we used to put cold towels, bags of ice, and other materials on our foreheads when we had fevers. This practice has changed after Netsusama Sheet came to be widely recognized. Now, when one has a fever, one attaches this cool sheet to one's forehead.

Today, Netsusama Sheet is sold in about 20 countries in addition to Japan, and overseas sales account for more than 50% of the total. The thoughtful development of niche products is a unique strength of Japan.

Netsusama Sheet, which is one of the top ten souvenir gifts purchased by foreign tourists according to some data, created a new custom when one has a fever. Although this custom has also taken root overseas, the reality is that there are many cheap counterfeit goods. As an intellectual property strategy specifically targeting countries overseas, though it is unrealistic to expect the company to completely control the market, Kobayashi Pharmaceutical is taking measures to protect their brands by promptly and agilely taking repeated action to fight against counterfeit goods monthly without waiting for the President’s approval.

  • * Netsusama Sheet is sold overseas under the product name "KOOL FEVER".

Message from Kobayashi Pharmaceutical

Netsusama Sheet is now a core brand of the company. We even have a Netsusama Boy monument in our building.
It is critical that new products leverage your technologies and also that they are based on consumers' needs.
We believe that it is important to stay aware and to continue pursuing the realization of what consumers wish for.

(Fig.7) The Netsusama Boy monument
(Fig.7) The Netsusama Boy monument

[Last updated 4 July 2022]


General Affairs Division,

Japan Patent Office