Another reason to choose silpoly over silnylon

[Jon Solomon]

Polyester has a lower environmental impact than nylon.

[Jon Solomon]

As this got double posted (my bad!), please post replies in this thread, not the other one. Thanks!

[Diane “Piper” Soini]

Those kind of charts always seem a little dubious to me. The amount of water for cattle is dubious because first of all, they are living beings and need the water during their lives anyway, and much of that water is excreted back into the land as they roam around the ranges of the west. Only a small amount of their lives is spent in a feedlot. Secondly, a lot of the end result of the animal went for meat and other products, not just leather. Third, the chart is missing some externalities. What about the plastic pollution of synthetic materials? The are finding plastic particles in all animals of the food chain, and plastic microfibers at the bottom of the Marianas Trench. I’m sure there are other parameters not looked at.

[Jon Solomon]

I’d just like to recall that while the chart compares many different textiles, my post was about nylon versus polyester.

I’m aware of the bitterly contested debates raging around leather and fossil fuel derived substitutes these days, but that’s totally off topic. If you want to talk about that, please start a separate thread. Thanks.

[Michael B]

Have a source to cite?

[Jon Solomon]

That chart that I included in the original post refers to the Higg Materials Sustainability Index based on data retrieved in 2017.

[Jon Solomon]

The original source of the chart is the 2017 Pulse of the Fashion Industry Report. https://www.globalfashionagenda.com/publications-and-policy/pulse-of-the-industry/

[Rex Sanders]

So has anyone found good silpolypro lately?

:-)

— Rex

[Jon Solomon]

Excellent for use in places prone to highly acidic precipitation ;-)

[Eric Blumensaadt]

Hmmm..

->nylon is stronger than polyester

->polyester stretches far less than nylon

->polyester is more UV resistant than nylon

So, could lightweight polyester fabric be strengthened with Dyneema ripstop and silicon coated for a reasonable price? Best of all worlds finally achieved.

[Jerry Adams]

I think that polyester stretches about the same as nylon, but it doesn’t change as much when the temperature or humidity changes.  By the way:)

[Rex Sanders]

The strength difference between nylon and polyester almost perfectly matches the strength loss of nylon when it gets wet, and it’s strength loss after not-that-many-days of exposure to sunlight.

So if you only set up and take down your nylon tent at night and it doesn’t rain …

Nylon’s “strengths” still don’t outweigh the other benefits of polyester.

Like virtually not stretching when it gets wet, even from condensation and ground moisture. And not absorbing water like a sponge, then almost refusing to dry out. I have painful experience with both those problems on nylon tents, not repeated when I switched to polyester.

Plus having about 25% less environmental impact.

Interesting chart. Will be more interesting when they get actual “Chemistry” numbers.

— Rex

[Sam Farrington]

“Those kind of charts always seem a little dubious to me. ”

Could not agree more.  A long and recent thread on BPL argued poly vs nylon to death, and both sides of the issue were represented by charts.  Jon’s subject is probably too nebulous to nail down with a chart, as Diane suggests; but for comparing utility of a fabric for tents, it should be possible to at least state the methodology of the testing.  But even that still gets into advanced science that is not much help for most.   Too often, information on line is not worth its pixels, and charts are no exception.

We don’t even have clear and meaningful labels to identify the different good and bad characteristics of tent fabrics, so we talk about “stretch,” “bias stretch,” “sag,” “strength,” “durability,” etc, and confusion reigns.  So I’ve found that cruising the chat pages and reading about complaints hikers have had with tents is actually more helpful, even allowing that one does not have enough knowledge to consider the source in on line chats.

I’d say to Eric that I’ve found 15D silpoly that has more bias stretch than 15D silnylon.  The breakdown of the integrity of nylon fabric when exposed to cold and moisture is also a puzzle.  Much seems to depend on quality of the nylon, but at least we’ve been told to look for 6.6.  But agree with Rex’s description of Nylon’s “stretching” and why it is a major problem.   As he suggests, the “chemistry” would be useful to know, although moderator Roger Caffin had a career in fabrics, and after much pressing, he did not provide me with an explanation of why nylon breaks down as it does, at least none that satisfied me.  Readers of the MYOG forum may know that I finally broke down and stuck a prototype of a tent canopy out in the worst cold, mush and drizzle this year for a day to see exactly how the particular canopy was affected.  Thank heaven there is a walk-out basement on the house.

Not long ago, we did not have much in the way of polyesters, so there was no real choice.  Now that there is a choice of sorts, I’m with Rex.  Except perhaps for tent floors of 6.6 nylon.  I’ve used even “6” silnylon on a number of tent floors and they held up very well in 20 or 30D weights.  Am about to embark on a tent that uses polyester, but since it is new, have little experience to know what weight will suffice to withstand the beating that floors take.  Even designed a tent with a smaller than usual fly, so if a 15D polyester failed in some way,  it would be much simpler to just make a new fly out of 20D ripstop polyester.

So choice of fabrics can get complicated enough that decisions can’t be made with reference to a few charts.  As for environmental impact, firmly believe it is a problem that requires major  governmental regulation of a number of powerful industries, and that the choice of fabric to use for my tent will not make a dime’s worth of difference.   Call me Ishmael.

[Jon Solomon]

“Those kinds of charts”?

This chart was compiled by the Sustainable Apparel Coalition, which developed the Higg Index to measure environmental impact of textiles.

Criticisms directed specifically at the Higg Index’s protocols and data make sense.

Criticisms on transparency of data behind the Index have led to moves to make the data and proctols public

U Cal Berkeley research team points out that the Higg Index lacks meaningful incentives to create change

Comments that don’t address specific issues with the Higg Index contribute bluster that may be individually satisfying, but it’s hard to see how they add anything meaningful to the discussion.

The problem of appropriate policy/actions to deal with environmental issues is an important one, but manifestly not the topic of this thread. Once again, this thread is about the environmental impact of nylon vs. polyester. It is NOT about the relative benefits of cow leather, nor is it about the suitability of nylon vs polyester for outdoor applications like shelters (a topic that has already been discussed extensively in other threads, as Sam points out), nor is it about the appropriateness of government regulation, industry self-regulation, or consumer decision in the fight against environmental catastrophe.

Now let’s get back to talking about silpolypropylene!

[Michael B]

With material manufacturing, there is not typically any free lunch. A lower cost (both environmentally and cost) material often results in less performance. If you want to experiment with a waterproof polypropylene material, look no further:

https://www.homedepot.com/p/BOEN-Heavy-Duty-Blue-Poly-Tarp-Cover-20-ft-x-20-ft-Waterproof-Tarpaulin-BT-2020/204074904

[Geoff Caplan]

Bit baffled by the direction of this thread. I know we like to geek out here, but people seem to be overthinking this.

What Jon is pointing out is simply that a group of scientists who spend quite a lot of time researching the issue have found that silpoly production is probably a bit less polluting than silnylon production. Which is useful to know.

And that’s pretty much it. Or am I missing something?

The main issue not covered by the chart is life in the field. Obviously, if one or the other fabric needs replaced more often, that might more than offset any differences in production. But given that silpoly has the better UV resistance, there’s no reason to believe that it would fail quicker than silpoly. Probably the reverse.

So on balance, I suspect that Jon is right and silpoly is the greener fabric.

[Kattt]

^^^ this.
Otoh if one owns a silnylon and then replaces it or buys a silpoly one on top of it, then they miss the mark. Using what you have is always greener.

[Michael B]

keeping  the thread on topic, I will concede that I value environmental impact of a material, but I value it far less than I value the utility of a material. The chart presented may not even well represent the manufacturing process of the materials we use (in production of backpacking materials, specifically). I have no idea how the data was collected, whether the material I want to use, specifically, was included in the data collection, or what subsequent processes applied to that material did to the scoring. All of this matters and, none of it can be deduced from the very generalized statement you’ve provided with the linked chart.

In keeping with the topic, what has been presented is not another reason to choose silpoly, as I have no reason to believe there is only one process to make silpoly or silnylon based on the info given.

[Jerry Adams]

I especially like the pie chart “fraction of this image which is white”…  I’m laughing at myself to be clear.

what Kat said – to be environmentally conscious quit buying new stuff.  Goodwill isn’t too bad.

OTOH – “hi my name is… and I’m an MYOGolic” – I keep buying new fabric for new projects.  I try to contain myself though.  My quilt is 24 ounces.  A few mouseholes but otherwise not too bad.  I’m going to make a new one because it will be 16 ounces.  I’ll keep the old one as backup in case something happens to my primary.

[Michael B]

Thanks for keeping it light, Jerry. I enjoy XKCD references.

what you said: keep/use stuff as long as you can – another good thing about myog is that you can design a product to minimize material waste, so you are throwing away as little as possible, regardless of material selection.

[Jon Solomon]

So what you’re saying, Mike, is that it’s impossible to extrapolate from the chart compiled according to the Higg Index methodology any meaningful conclusions about the environmental footprint of silpoly vs silnylon. Is that what you’re saying?

Do you have any information about different/alternative processes used to make silnylons and silpolyesters?

Are the differences between different types of polyester meaningful for the assessment of environmental impact?

Does anybody know of any studies where the environmental impact of nylon and polyester is compared? And of anything related specifically to the siliconised fabrics that occupy such an important place in our outdoor gear?

[Jon Solomon]

Personally, I’m willing to carry extra grams if it allows me to use materials that last longer and have less impact.

I’m kind of hoping that this thread is one more of those that could contribute to greater interest in the environmental impact of outdoor gear.

I noticed that RSBTR introduced a line of 20D silpoly that is made from recycled materials. The color choice is limited at this point, but it’s an interesting development.

On the other hand, recycling polyester has its limits and cannot be done indefinitely, since the fibers break down after a couple of cycles and can no longer be recycled.

Based on the experiments conducted by Xavier Nitsch, silpoly is far more usefully durable than silnylon after prolonged exposure to sun and rain. Product longevity is probably one of the most important contributions we have right now to lessening the environmental footprint of shelters while still using really light, performance materials.

[J-L]

Yama Mountain Gear uses the recycled silpoly:

https://yamamountaingear.com/pages/environment

[Michael B]

I also am willing to carry a few more g’s on my back for a more sustainable product, or one that I knew would be recycled if I threw it in the recycle bin, or had a known way of sending it to someone for recycling.
As it stands, I measure my product lifespans in multiple years, so it isn’t as much an issue for me, but I am happy to support manufacturers who are transparent and actively prioritizing environmental impact in some way.

[Jon Solomon]

That webpage is chock full of a lot of other cool environmentally concerned initiatives undertaken by YMG.

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