Gore-tex: Time for alternatives. Part 1 | PART 2 | Part 3   

Actually, we don’t need teflon

In a short online essay, Elizabeth Sanberg finds herself in a dilemma when buying outdoor clothes: choosing for the environment or choosing for own convenience [10]. Although it is appreciable that the author draws attention to the problems with Gore-tex, I hope to convince the reader that is no need for choosing between environmentally friendly and comfortable.

I will discuss two alternatives for teflon membranes. The first one is in my opinion often the best one, and consists of using clothes without membranes. This is especially useful for boots and in conditions of temperatures below zero. The second option is simply using another kind of membrane. This is a really easy option, but leaves the consumer with all the disadvantages that also come with teflon membranes, apart, in some cases, from the environmental harm.

Alternative one: Better without membrane!

Although one can easily think of conditions where a waterproof membrane is highly appreciable, people often forget that in many more kinds of weather the membrane does more bad than good. I will illustrate this for boots and jackets.

Boots

Let's start with leather hiking boots. The basic problem is simple, and involves the trade-off between treating leather to be waterproof versus breathable. In my experience, no wax or silicone exists that can at the same time impregnate the leather to be waterproof for longer than a couple of hours and at the same time leave it very breathable. If you expect dry weather, it is best to put some lighter wax that keeps the leather breathable, and hope that you don't encounter long rain showers or deep water puddles. If you're going to stay in a wet climate, it is better to give in on breathability, and treat the boot with a heavier wax that will keep the leather dry for longer. Taking two extremes, we have at one hand the leather with high breathability and little resistance to water, and on the other hand leather which almost doesn't allow any vapour to pass, but which will remain dry after being immersed in water for many hours or days. Note that the lighter the leather is treated (or the more breathable), the longer it will take for the leather to dry once it got wet. And wet leather will not 'breath' at all.

Now add a membrane to the picture. The breathing capacity of a PTFE membrane is better than that of a plastic bag, but not far as good as that of lightly treated leather. To keep it short and simple: no matter how the leather is treated, a membrane will in all cases significantly decrease the breathability of the boot. Illustration 3 shows the combined effect of a membrane and the leather on breathability of the whole boot, for different degrees of waterproofness of the leather. Although exact values depend on both the membrane and the leather, it can be assumed that the breathability of a membrane would be somewhat lower than that of very breathable leather. Of most interest are the very left side of the graph, showing boots with high breathability for in warmer and dryer conditions, and the very right side of the graph, representing boots with good waterproofing and low breathability. As you can see, adding a membrane to well breathable leather reduces breathability of the leather and membrane combined (overall breathability) really a lot. For the more waterproof boots, a membrane does not reduce breathability so much. On the other hand, the leather is so waterproof that the membrane would be completely superfluous.

For all kinds of leather, a membrane increases the drying time of a soaked boot a lot. And last but not least, on points where the leather experiences a lot of friction or bending, the membrane will often tear and leak long before the rest of the boot is at the end of its life. A boot with a broken membrane will have the lower waterproofness of a boot without membrane, and the lower breathability of a boot with membrane.

Jackets

As for leather, any jacket will lose a significant portion of its breathing capacity by adding a membrane to it. Especially when you are walking in warm weather or uphill, there won't be any membrane that can cope with all the sweat. At the other end of the temperature spectrum, membranes become completely useless in conditions colder than a few degrees minus, since the air is usually dry and rain is not an issue. Any wind-proof outer layer will do the job here, and probably perform better than membrane-lined garments concerning breathability. In intermediate conditions however, it can't be denied that membranes have some merits, especially in relatively dry weather with rain showers now and then. However, because of the heavy environmental and health impact of PFOA, alternatives for PTFE membranes should be looked for.
Although both felt (the oldest fabric known to humankind) and different 'soft shells' (synthetic fabrics with properties in between fleece and waterproof garments) have high breathability and can withstand water for a long time, neither of them are satisfying under long-lasting rains. Fortunately, good alternatives with physical properties comparable to PTFE (or even better) are on the market already! And for sure you even know the names of some. It's time to explore alternative two.

Alternative two: Use another membrane

Most outdoor brands, whether they also sell Gore-tex or not, have their own brand of waterproof membrane. For example the North Face (USA) markets technical clothing with HyVent. Fjällräven (Sweden) proudly presents Hydratic and Haglöfs (Sweden) features Haglöfs Proof. Jack Wolfskin from Germany uses Texapore and Regatta from the UK has Isotex. Are these the perfectly environmentally friendly alternative to Gore-tex/PTFE? After interviewing some of those companies on the phone, the following became obvious. Most membranes (altough not Gore-tex, eVent and Sympatex) are actually made of polyurethane (PU). The 'building blocks' (or monomeres) of PU, isocyanates, are not innocent for living organisms, but on the other hand they don't come close to PFOA as an environmental threat, and in normal conditions the finished product (PU) does not pose any risks for health. When it comes to the quality of the product, it cannot merely be stated that PU is good or bad. Just as for PTFE membranes, whether the product will be waterproof and have a long life expectancy or not depends more on other compounds of the garment (such as the seams and other layers in the fabric protecting the membrane) than on the actual membrane. PU is also more versatile than PTFE, in the sense that it for example also can be used as a laminate rather than as a membrane. This makes it possible to make stretchy garments, something not possible with PTFE.

Even though the switch from PTFE to PU is surely a step in the right direction, there is one more thing that should not be forgotten: the Durable Water Repellent treatment, for which most often still PFOA is used. Even though PFOA might be an efficient water repellent, there are good alternatives as well. Nikwax, for example, has a range of environmentally friendly, fluorocarbon-free products to make garments water repellent.

The good news is that some companies have already decided to use neither PTFE nor PFOA in their garments. Only PU membranes are used, and for making the outer layer water repellent other products than PFOA are used. The next paragraphs will help you on the way to find 'green' products.

Part 1 | PART 2 | Part 3