About waterproofing
Waterproofing is a process that makes a product waterproof or water-resistant so that it remains relatively unaffected by water. When talking about fabrics, it means they have been treated to become resistant to penetration by water and wetting.
Normally fabrics (natural or synthetic) are laminated or coated with a waterproofing material such as rubber, polyvinyl chloride (PVC), polyurethane (PU), silicone elastomer, fluoropolymers, and wax.
The term you always hear when there is a discussion about waterproofing fabrics for outdoor clothing is DWR – Durable Water Repellent. It is a technology where polymer coating is added to outerwear to provide water-resistant protection.
The very common classification for waterproof fabrics is the following:
- Showerproof
- Water-resistant
- Waterproof garment
Showerproof fabrics are meant for light rain, but after a short time, water will penetrate the fabric. Water-resistant fabrics are slightly more resistant and waterproof garments have water-repellent coatings with the seams also taped to prevent water ingress there. Waterproof garments also specify their hydrostatic rating ranging from 1500 for light rain to 20 000 for heavy rain.
Fluorocarbon-based textile finishes
In the early 2000s, the most common treatment was the application of C8 fluorocarbon-based textile finishes during manufacture. It has been the textile industry’s standard as it is not only making fabric waterproof but also resists heat, grease, and stains. However, despite its effectiveness, the known brands have been recently looking for alternatives due to serious environmental and health concerns related to C8 fluorocarbon. The main issue lies in 2 side products when creating fluorocarbons: PFOS and PFOA. Both are PBT (persistent, Bio-accumulative, and toxic). There is no way to produce fluorocarbons without these two side products.
PFOA has not only PBT, but CMR (carcinogenic, mutagenic, or toxic reproduction) properties, due to which it has been classified as a substance of very high concern. In 2014 there was a document released called The Madrid Statement, which was signed by more than 250 scientists from 38 countries, and which documents the scientific consensus regarding the persistence and potential for harm of poly- and perfluoroalkyl substances, and lays out a roadmap to gather needed information and prevent further harm. The document also encourages societies to limit the production and use of the entire class of PFAS.
As mentioned earlier, PFOA substances are very persistent in the environment and they have been found in the blood of the general US population where it remains for a very long time and can cause developmental and other adverse effects (tested with laboratory animals).
Future tendencies
The industry has been slowly moving from C8 fluorocarbon to C6 fluorocarbon-based finishes (short-chain fluorocarbons) and towards the development of alternative chemistries not involving fluorocarbon at all or by creating hybrid systems. Here are some of the examples:
- RUCO-GUARD and RUCOSTAR technologies that use only C6 fluorocarbon finishes
- BARRIER: fluorocarbon-free Durable Water Repellence (DWR) technology
- NUVA: C6 based fluorochemical microencapsulated coating by Archroma
- Eco-release: products contain fluorine (not in the form of C6 or C8) and is characterized by dual-action technology (repellency and release)
Many known outdoor brands (e.g. Patagonia, North-Face, Helly Hansen, Burton) have aimed to move towards fluorocarbon-free finishes by the end of 2022-23 and some of their high-end products are already PFAS free. However, so far the move has been slow and most of their products still include hazardous chemicals as per Greenpiece study in 2016.
Patagonia has invested 20 million dollars in a Swiss company called Beyond Surface Technologies to develop better chemistry for outdoor apparel. They are also very honest about the treatments and chemistries they use for their apparel and talk about them openly in their blog. One of the things they point out is that when looking for alternative solutions, it is important to keep in mind they would be also durable as if a waterproof coating wears off very quickly, it results in more textile waste which is an issue itself. I am strongly supporting this thought.
North-Face has created a new woven material called Futurelight in 2019 which was a waterproof fabric that uses 90% recycled materials in its productions.
Fjällräven is advertising their waterproof Eco-shell material which is made from recycled polyester and fluorocarbon-free impregnation.
Gore-Tex (the most known company producing waterproof fabrics that many known brands use) released the first DWR free of PFASs of environmental concern in 2018. Over half of their customers’ outdoor products, today use this formula, but it does not replace all rain shells.
And then there is a known high-end British brand Barbour that is still using waxed cotton for waterproofing its jackets – technology from the first half of the 20th century. Waxed cotton is cotton impregnated with a paraffin or natural beeswax-based wax, woven into or applied to the cloth. It developed from the sailing industry in England and Scotland. The two main negative aspects of waxed cotton are that it is not very breathable and is normally heavier and bulkier than modern synthetic waterproof materials. However, some customers own these jackets for decades and Barbour also offers a repair service that patches and reinforces jackets. If their products are good enough for Queen Elizabeth, they are good enough for you.
The examples above show there are steps being taken to make fabrics waterproof by using more sustainable and less harmful technologies, but these steps are still too slow and we were only talking about a few very known outdoor apparel brands that show the interest to change. It is also important that the governments are taking more action to regulate the entire textile industry and help to make it more sustainable. Let’s be honest, considering what is happening in the world, instead of small steps, there should be a race towards more sustainable technologies and not just in the textile industry.