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Comment by troyvit | Hacker News Reader

Wow I had no idea.

Here's a link that talks about makers of outdoor gear and their relationship with DWR. http://www.detox-outdoor.org/

It doesn't look like there is a lot of choice. Maybe I'll just stay wet :)

The whole breathable/gore-tex thing is overrated as they all rely on liberal use of DWR chemicals that tend to be waterproof only for a while. So regular retreatment, which never seems to be as good, or acceptance of wetness is needed. :)

I'm surprised to see Patagonia in the worst of that site's categories, considering their stance on sustainability.

Gore-tex (at least the heavy 'classic' kind) doesn't have any refreshable coating. Its an inner layer of moisture wicking mesh, stuck to a thin rubbery ptfe membrane of some sort and an outer very abrasion resistant layer which is hydrophobic when clean. It can be boil washed and special treatments are advised against. It is very waterproof while surprisingly breathable.

Hmm, as far as I can remember, every gore-tex item I've owned across the decades -- mainly from the better outdoorsy brands -- has needed a refresh, and warned to expect that on the label or leaflet. Some lasted longer than others. One that was left far too long without eventually gave about as much water protection as a cotton jacket. Whether any of them were "classic" gore-tex or not, I don't know. I've always understood it as the middle breathable layer with several bonded layers, and chemically waterproofed outer.

Wikipedia seems to agree about the outer, and only notes a decline in breathability in newer fabric by using a PU layer in place of teflon bonded to fabric found on the earliest.

https://en.wikipedia.org/wiki/Gore-Tex

No, Gore Tex -- and all other membrane systems -- rely on DWR to keep the face fabric from wetting out. The face fabric is only water repellent if it's finished with oil, wax, or DWR. When the finish is degraded, rain will wet out the shell and breathability plummets. There are no exceptions. If you invent a fabric that is both breathable and permanently water repellent (as in, it sheds water in beads), then I promise you'll become wealthy beyond your wildest dreams :)

Well, in the 90s before they had lots of grades, the instructions where to never put anything on it, just wash and tumble dry. It has a slightly coarse texture like it has microhairs. It can bead water but can also get wet, but when it is wet the water flows off it quickly, not into it. Ive never expected wet gear to be incapable of getting wet, just to resist it, drain quickly and not let water in. But i've never used repellent sprays.

Somewhat serious question: do you think it matters if it looks absolutely silly?

Sorry, if what looks silly?

Gore-tex does stay waterproof. It just can't breathe once the outer fabric soaks through, which results in clamminess. DWR delays this & keeps it breathable for longer in wet conditions. Gore is not a great solution if you'll be drowning in rain but for intermittent showers, meltwater and snow it has time to dry out. Especially if you're moving & generating heat.

What is a better engineered membrane than gore-tex?

I'm not sure what you mean, but pretty much all breathable membrane systems in clothing work this way, depending on DWR to maintain breathability.

The one radical entrant in the market is gore shakedry, which is pretty simple- the face fabric is omitted, and therefore the need for DWR. The exterior of the jacket is literally the gore membrane. The moisture performance is reportedly superior. The consequence is extremely poor durability against abrasion, to the point you cannot wear a pack over it.

On the other hand, I'm completely unsurprised to see archie on the bottom list.

Honestly people have “stayed wet“ for centuries without chemicals. We’ve hung our clothes to dry instead of using machines too.

Lots of apparel products are highly overrated. And those water resistant coatings just come off anyway.

I think the best thing to do is go on a hike near a river with a dog, and watch how the dog marches through the water unwaveringly even when it’s cold!

There's also waxed cotton and oilskin. Some maintenance required, but they work.

Unless you really saturate cotton in wax/oil so it has no breath-ability, it only holds up against showers. It becomes sodden and little use in persistent rain. PU coated polyester rainwear can perform on a different level in persistent rain. I've not found natural materials which perform as well, although some expensive tweeds are reportedly exceptionally good.

That site isn't loading for me. I would hope that vapor-permeable membranes work (e.g. gore-tex). The only problem is that the outside of the garment gets wet, and they're not very breathable

Gore-tex is PTFE, also known as Teflon, which is a flurocarbon. Several of the waste products or reactants for making Teflon are in the same category as DWR products, and are basically toxic forever. There's not much you can do if you need fabrics with these properties, you just need to pick you poison.

But Teflon doesn't react with anything. That's its purpose. So even though it's a fluorocarbon, it's unlikely to cause health problem because it just won't react with your body. Or is there some other mechanism through which it causes damage, such as blocking something by physically being in the way?

Consider what happens to your immune system when it detects a foreign particle that it can't get rid of because there's no way to interact with it.

What happens? I'm not an immunologist, and "common sense" certainly doesn't seem like the way to think about the behavior of something as complex as the human immune system.

The human immune system doesn't need to "interact" with a physical particle. White cells envelope (standard attack) a foreign particle, then dies around them, and the resulting envelope is expelled. Your body is mostly fluid. Internal fluids don't really need complex chemical interactions but the dead white blood cell acts as an effective envelope for transport, by design. eg mucus in your nose when you're sick.

For the most part, what happens is nothing. PTFE is completely biologically inert, which is why it's commonly used in surgical implants and prosthetics. Only the finest particles (<100 nm) have been established to present a biological hazard, and these are very hard to come by.

Ingested PTFE passes right through the digestive system unaltered. You can scrape the non-stick coating off of all your pans and eat it, and there will no detectable fluorinated chemicals in your blood.

However, if you heat that nonstick pan above 600 deg F, the decomposition products can easily injure you, and sometimes worse. But even in this case, and main danger does not appear to be microfine PTFE particles, but rather chemical nasties like fluoroacetates.

There are many studies on this. One example: https://www.ncbi.nlm.nih.gov/pubmed/11042093 - "Pulmonary effects induced by ultrafine PTFE particles"

Just to clarify, if a large quantity of PTFE particles was introduced into your blood stream are you stating that wouldn't deprive your cells of oxygen? I think you're making some health related claims and assumptions that may be correct in limited circumstances but haven't been sufficiently studied to come to a good conclusion on.

Umm... yes? Why would PTFE "deprive cells of oxygen"? What cells? What size particles? Do you think they'd block your arteries or something? Why would that be any different than any other material? And how exactly would such particles get into your body? By injection?

PTFE is chemically and biologically inert. It's well studied, and has enjoyed extensive medical use inside peoples' bodies for over half a century. I'm aware of no evidence that PTFE in your body is harmful in any form or quantity that is known to actually occur in humans. If you have any evidence to the contrary, I'd love to hear it.

The process to ensure your cells get enough oxygen is a complex one. When you're exercising heavily certain chemical signals are sent out to ask the heart to increase blood flow to compensate for the high consumption of oxygen - similarly injuries produce stressor signals when the body is damaged and bleeding (since the lowered blood pressure decreases the efficiency of the heart's ability to deliver oxygen) - if an inert chemical was introduced into the blood stream slowly it'd gradually reduce the amount of oxygen carried in blood as it flows through your body by decreasing the proportion of red blood cells per volume, to compensate maybe your heart needs to beat a bit quicker deliver the same amount of oxygen via blood. Keeping your blood clean of impurities is traditionally (mostly) handled by the kidneys, if some PTFE is introduced into the blood stream does PTFE recognize this impurity as a dilution - will it properly filter it out? How efficient is that filtering and how much will it stress your kidneys?

Basically, bodies are complex objects - this is what studies are for and long term effects can take time to be detected. I don't have any evidence to the contrary, but I am skeptical of how conclusive the supporting evidence is and would place the onus on proving harmlessness rather than harmfulness.

You've invented a new medical hazard, which makes no sense whatsoever. If you were to somehow introduce enough solid matter into your blood that it lowers your RBC count on a volumetric basis, then you'd have far bigger problems than oxygen transport in general. And at that point, it wouldn't matter what the material is.

And you still haven't answered the question: how do you imagine such a large amount of powdered PTFE would get into your body? PTFE can't be digested, and there's no evidence that it's passed to the blood stream though inhalation. Are you really afraid that someone's going to inject you with a specially formulated suspension of ultra-fine PTFE?

The rest of your post is a bunch of mumbo jumbo.

> injuries produce stressor signals when the body is damaged and bleeding (since the lowered blood pressure decreases the efficiency of the heart's ability to deliver oxygen)

Not sure what "signals" you think you're talking about, but our compensation for traumatic hypovolemia is triggered by vascular baroreceptors, a mechanism has nothing to do with the effect of foreign particles in our blood.

> Keeping your blood clean of impurities is traditionally (mostly) handled by the kidneys, if some PTFE is introduced into the blood stream does PTFE recognize this impurity as a dilution - will it properly filter it out?

No, the kidneys do not filter out solids. That's not how they work. Your body has ways to deal with foreign particles, which vary widely depending on the nature of the material -- particle size and shape, reactivity, opsonizability, etc. None of these ways involve the kidneys in any significant way.

> I don't have any evidence to the contrary...

Nor, apparently, are you able to account for the half-century of experience we have in using PTFE inside people's bodies. Nor as well the material's track record in a huge variety of other applications. E.g., nearly every household in the first world has used PTFE-coated non-stick cookware. The fact that we have no evidence of PTFE somehow entering people's bloodstream and "diluting" their blood might clue you in to the plausibility of your theory. Or maybe not.

> ...but I am skeptical of how conclusive the supporting evidence is and would place the onus on proving harmlessness rather than harmfulness.

You can say that about anything. Literally anything.

Honestly, I know you think you're discussing a complex topic with some sort of clever reasoning, but it's only because you're missing a lot of basic knowledge of chemistry and physiology. I think I need to be done with this now.

>However, if you heat that nonstick pan above 600 deg F, the decomposition products can easily injure you, and sometimes worse.

If you have birds the fumes will kill them. It's that whole canary in the coal mine.

Adam Ragusea on YouTube (can't link sorry, restricted browsing) had a short video covering this as he reviewed the cases and research from experts. In the end the worst known case was basically a guy who fell asleep and the entire coating of his pan burned off, filling his house with smoke. He had respiratory symptoms and was hospitalised but walked out (I think) less than 48 hours later with no obvious lasting effects.

I think the post you are replying to though was angling that it would cause a sustained inflammation response as your immune system is detecting and gearing up to fight a particle it cannot deal with. I have no idea if that's true though.

>You can scrape the non-stick coating off of all your pans and eat it

This almost sounds like a dare. Maybe it could even be the new Tide Pods thing.

https://en.wikipedia.org/wiki/Polymer_fume_fever

https://en.wikipedia.org/wiki/Polytetrafluoroethylene#Safety

Those articles describe PTFE as "stable and non-toxic at lower temperatures", starting to degrade into concerning and toxic byproducts at 500F/260C.

As a rule, I try not to let my rain jacket reach 260C, but your local weather may differ?

PTFE coated pans definitely reach above 500F from time to time.

People who own birds are suggested to not use PTFE coated pans. Birds are much more sensitive to the offgased chemicals and there are numerous instances of people accidentally killing pet birds from these fumes, so it definitely happens.

Yeah- there are definitely problems with it on pans, but the context of the thread was for PTFE as a water repellent in clothing.

As far as I know, the concerns for uses where high heat isn't an issue are related to manufacturing byproducts- which can make their way into the final product, but also if the manufacturer doesn't dispose of them correctly, they can wind up in the environment.

It's almost a bit like Agent Orange (though probably not nearly as bad, at least not in the medium-term?)- the intended product isn't the problem, but the manufacturing process makes it really easy to let nasty stuff slip in.

But I don't know that much about this, so please correct me if I'm wrong! Not a chemist, I just read a lot.

Add for clarity: Goretex (like all modern waterproof-breathable products) is a system, which includes a PTFE membrane, as well as a DWR coating. The fabric is not breathable without the DWR coating, as it will "wet out."

Breathability is as much a marketing feature as it is a useful property of these garments/fabrics. Do they work well in cold/dry conditions? Yes! Do they work well in warm humid conditions (i.e. your average North America. Rainy day)? Not so much.

How old are you? The key feature is not breathability but "waterproof+breathable." You might not be old enough to remember airtight rubber raingear, or questionably waterproof oilskin, or horribly "water resistant" synthetics.

You also might not be into gear enough to have realized the significant spectrum of breathability between a nylon jacket, a 2.5 layer jacket, and a fully 3-ply goretex pro.

It is a real thing, not marketing, for many who care about and rely on these things for comfort and safety.

I am aware. I’ve sold this gear, have owned a spectrum of different types, and use it regularly. Humidity differentials are real. I stand by what I said.

Maybe one day they will make a rain jacket with an air compressor in it :)

Sodium is a precursor to table salt and it’s highly toxic. Would you consider table salt dangerous?

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