Which waterproofing spray is better: fluorinated, silicone-based, or hydrocarbon-based?

When choosing a water-repellent spray, there are many different types on the market, including fluorine-based, silicon-based and hydrocarbon-based products. I've written this article to explain the differences between these types of spray, and to help you choose the right one for your needs.

I run a cleaning shop specializing in outdoor gear. From my professional perspective, I'd like to share some tips on how to choose the right water-repellent spray for your needs.

The most effective water-repellent is fluorine-based

Fluorine-based waterproofing sprays are characterized by their excellent water-repellent performance. Fluorine has chemical properties that are not found in other elements, and because of these properties, it is possible to keep the surface tension energy of the coating surface, which is an important indicator of water-repellency, at a very low level. Because surfaces treated with fluorine can be made to have the lowest surface tension energy in theory, fluorine-based products can achieve the highest level of water-repellency. Furthermore, fluorine-based products can also be made to be oil-repellent. Only fluorine-based products can achieve a high level of both water and oil repellency. You might think that oil repellency is not necessary, but it is needed for stain-resistant performance. The fact that it repels not only water but also oil makes it much more stain-resistant, which is a great advantage.

Breathability and moisture permeability of fluorine-based waterproofing spray

As for the disadvantages of using fluorine, when it is used on clothing, you might be worried that it will impair breathability and moisture permeability, but this is not a problem at the level of concern. I mentioned earlier that fluorine is used in coatings, but please bear in mind that it is not a coating that fills the space between threads, but one that adheres to the threads. It is coated as a very thin film on the surface of the threads, so there is no need to worry about it interfering with breathability or moisture permeability.

Problems with fluorine-based waterproofing spray

However, in recent years, the problems with fluorine have become clear, and in environmentally advanced countries such as Europe, its use is being avoided. The problem with fluorine is a misconception, and the problem lies with the organic fluorine compounds used in waterproofing spray. The organic fluorine compounds used in waterproofing spray today are different from the restricted substances currently being viewed as problematic, and have been improved. However, there are still many things we don't know about the effects of organic fluorine compounds, and even though they have been improved, it is difficult to say that the problem has been completely eliminated. In Europe and other environmentally advanced countries, they are concerned about this part of the issue where it is difficult to say that the problem has been completely eliminated, and they avoid using them by not using anything that is suspicious. This trend is also spreading to Japan, and the number of fluorine-based waterproof sprays is gradually decreasing.

As waterproof sprays containing substances that are considered to be problematic as of 2024 are not sold in Japan, it does not mean that you should never use them.

Hydrocarbon-based waterproofing spray

Hydrocarbon-based products are being used as an alternative to the fluorine-based products mentioned earlier. Hydrocarbon-based products do not have the same environmental or health issues as the fluorine-based products. However, they do not perform as well as fluorine-based products.

Hydrocarbon-based water repellents are also currently being improved, and their performance is improving day by day, but it has to be said that there is still a big difference because fluorine-based water repellents are too good. If you are only looking at water repellency, you can get close to the performance of fluorine-based waterproofing sprays to a certain extent, but the big drawback is that they are not oil-resistant.

The Drawbacks of Hydrocarbon-based Waterproofing Sprays

When it comes to oil repellency, you may be wondering whether it is necessary, and whether waterproofing is sufficient. However, this is not the case in practical terms. When used in everyday life, the atmosphere contains various oils. As people's sweat and skin also contain oil, simply touching something can cause the water repellency to disappear at the same time due to the lack of oil resistance. If it is rainwear, etc., this could lead to the loss of water repellency in the parts that come into contact with the skin. In fact, oil repellency also contributes to maintaining water repellency for a long time. The realization of a high level of water and oil repellency was achieved with fluorine-based waterproofing sprays. Even with the silicone-based and hydrocarbon-based products mentioned below, it is difficult to achieve this. This is due to the chemical properties, and as of 2024, no manufacturer has yet been able to overcome this challenge.

Silicon-based waterproofing spray

Like hydrocarbon-based waterproofing spray, silicon-based waterproofing spray is attracting attention as a substitute for fluorine-based products. You may have heard of it before, as it has been used alongside fluorine-based waterproofing spray for some time.

In terms of water repellency, silicon-based products are not as effective as hydrocarbon-based products, and they are also not as effective as fluorine-based waterproofing spray. The basic performance is the same as that of hydrocarbon-based products. This is because silicon (or, to put it in English, silicon) is used in silicon-based products, but it is not used to contribute to water repellency, but rather to the framework, so the part that contributes to the water-repellent surface is the same as that of hydrocarbon-based products. For this reason, it has the same disadvantage as hydrocarbon-based products, which is that it does not have oil repellency.

Silicon is a property that is often found in glass, so it is possible to give it glass-like properties. In that sense, it may be advantageous over hydrocarbon-based products in terms of improving the durability of water repellency. However, hydrocarbon-based products are also being developed, so it can be said that the superiority of either will depend on the future development situation.

There have been no problems found with fluorine in terms of the environment or human health, and it can be said that fluorine-based waterproofing sprays are currently the most widely used alternative to fluorine-based products.

Can silicone-based products not be used with Gore-Tex?

There are several articles that say that silicone-based waterproofing sprays cannot be used with waterproof breathable materials such as Gore-Tex because they remove breathability and moisture permeability, but this is incorrect information. Even if they are silicone-based, most of the sprays currently on the market are not waterproof, but rather are designed to make the fabric water-repellent, so they do not have the effect of blocking the weave of the fabric, but rather coat the threads to make them water-repellent. This is why the endorsements on the waterproof sprays sold by major manufacturers these days state that they can be used on waterproof-breathable materials such as Gore-Tex.

Summary

In this article, we have explained the characteristics, advantages and disadvantages of fluorine-based, hydrocarbon-based and silicone-based waterproofing sprays from the perspective of a professional outdoor cleaning expert.

In the future, there is a trend towards the fluorine-based sprays becoming unavailable or no longer being sold, so it is important to understand the characteristics of the hydrocarbon-based and silicone-based waterproofing sprays, as well as keeping an eye on future developments.