We've studied DWR as an outdoor maintenance professional.

There are already several methods to regain the water repellency that is lost when using rain jackets such as Gore-Tex, such as waterproof sprays and water repellents such as NIKWAX.

However, we were not satisfied with any of these methods. It is true that immediately after applying these water-repellent treatments, the water-repellent performance seems to be restored, but once it rains for a while, the original water-repellent state is lost again.

We would like to do something about this and introduce droproof, a water repellency reactivation service that we developed after much research to make the water repellency performance last longer.

Originally founded as an outdoor equipment rental service

Our beginnings date back to June 2010.

It all started when Mr. Murono, the representative of SORANOSHITA, started a rental service specializing in outdoor equipment that could be ordered online and received anywhere in Japan.

Such a service did not exist in Japan at that time.

Many people were able to use this service to rent specialized outdoor gear, from full-scale mountaineering equipment to general camping equipment.

The service was especially used by many when using Mt. Fuji is the highest mountain in Japan at 3,776 meters above sea level, so specialized equipment is required. At that time, this service was ideal for climbers of Mt. Fuji because they could borrow specialized equipment on a short-term basis.

We carried a lot of authentic gear, including Gore-Tex.

Because we were a specialty mountaineering and camping store, we were very particular about what we carried. Therefore, we used Gore-Tex for rain jackets and sleeping bags that could be used in the mountains in winter.

Rental service itself is a service that has been offered for a long time, if not on the Internet, at ski resorts for example. However, the products available there were only inexpensive and maintenance was only done once after the season ended.

We differentiated ourselves by offering authentic mountaineering gear and renting out a lot of Gore-Tex jackets, which made us aware of the problems with Gore-Tex jackets.

At first we too used water repellent, using waterproof sprays, Nikwax, etc.

In order to rent out outdoor jackets and climbing shoes, at first we too washed our used gear as introduced by the manufacturer and Gore-Tex, treated it with water repellent sprays and Nikwax, etc., and then rented it out to the next person.

However, even if we did the maintenance as introduced by the manufacturer and Gore-Tex, the performance recovery was not satisfactory.

Rather, because of our position as a rental service provider, we often recognized the difference between rain jackets that had been rented out and washed many times and those that had only been used one or two times.

We were in a position to understand better than anyone else how rain jackets that had been used in this way would deteriorate and lose their water repellency. We were also in a position to realize that jackets that had lost their water repellency would never fully recover, even if they were maintained using the treatment methods recommended by the manufacturer and Gore-Tex.

As professionals, we wanted to loan out jackets with sufficient water repellency.

At that time, we asked ourselves whether it was really right for us, as professionals specializing in outdoor equipment, to lend out rain jackets with insufficient water repellency. We thought that because we are professionals, we should lend out rain jackets with good water repellency.

That is where our quest for water repellency began.

Understanding Gore-Tex fabrics

We began by investigating Gore-Tex fabrics. At first, we did not fully understand GORE-TEX fabrics. Why does it lose its waterproof and water-repellent properties, why is it layered, and why does it need to be maintained? As we investigated these questions one by one, we came to understand the characteristics of Gore-Tex fabrics. Of course, at the same time, you will also learn how superior GORE-TEX fabrics are. However, our sense of mission for maintenance became very strong when we realized that the excellence of GORE-TEX fabrics can only be fully utilized if they are water-repellent.

Problems with Conventional Water Repellent Treatments

So what is the problem with waterproofing sprays and water repellents such as Nikwax? It took us a long time to solve this problem. We cut up several GORE-TEX jackets into test pieces and tested them repeatedly, resulting in more than 100 GORE-TEX jackets that were tested.

The result of losing these jackets was a revelation. The rain jackets sold are not treated with water repellents such as waterproof sprays or Nikwax. The rain jackets on the market were treated in a completely different way. The process was different to begin with.

It was only natural. The rain jackets sold in the market are mechanically treated in factories, but we do not have such machines to do water repellency treatment ourselves. These are excellent products that satisfy many people because they are easy to use and restore water repellency, but they are not suitable for higher-level treatment.

We climbers need to work in the rain all day long, so we are not satisfied with the general purpose products. To achieve a higher level of water repellency, we needed to use the same equipment as used for the rain jackets sold in the market.

It is also difficult to apply the same treatment to rain jackets sold in the market.

Unfortunately, the process did not work as well as we thought it would, because it was not as easy as it sounds. It was not that easy.

In fact, the rain jackets sold in the market are not water repellent in the form of rain jackets. Instead, they were treated with water repellency as rolled fabric before being processed into rain jackets.

Therefore, when the same water-repellent treatment was applied to the garment rain jackets, the fabric and rain jacket components were damaged. It was the moment we hit a big wall. Finding a solution is not easy.

Why do the rain jackets sold have better water repellency than waterproof sprays?

We patiently investigated why the rain jackets on the market had better water repellency and why water repellent treatments such as waterproof sprays and Nikwax could not perform as well, and we worked out what was the key to achieving the desired performance. We then determined what was the key to achieving this performance, and the result was our water repellent technology, DANSUI COATING.

These are different processes from water repellent treatments such as waterproof sprays or Nikwax, nor are they the same processes used for rain jackets on the market. We have created our own process, and we have also created our water repellents to adapt to it. In other words, our water repellents are made to perform with our process. We are often asked to share our water repellents, but unfortunately, we cannot deliver performance if we only give you the water repellent. It is not only the water repellent that can deliver performance, but the process is also important.

In order to provide the water repellent technology developed in this way, we started a water repellent treatment service called droroof in Japan in 2015. In 2023, we will offer a PFC-free service.

Japan is not the only country in need of these water repellent technologies. Nowadays, when people are demanding sustainable initiatives, they want to maintain their products and use them for longer.

It is in this environment that we believe our DANSUI coating technology and droproof service is needed to restore the water repellency of GORE-TEX jackets and other specialized garments to a higher level of water repellency and to make them reliable again.

Therefore, we would like to collaborate with partners in various countries to provide this service outside of Japan. If you are interested, please contact us.