Jon,
Re:Â “Once again, this thread is about the environmental impact of nylon vs. polyester.”
“Now let’s get back to talking about silpolypropylene!”
Is it some or all of them that you have in mind?
Just guessing, but given polypropylene’s lesser detriment to the environment, that may be what you’d like to talk about.
Unfortunately, woven polypropylene, or olefin, or oly-fun as Walmart and Joanne’s Fabrics call it, is used to upholster outdoor furniture and is a bit heavy for superlight backpacking, the polestar of these forums.
Non-woven prolypropylene, however, has burst upon markets worldwide for use in protective masks, and can be very light in the same ranges as DCF. It can be ordered as yard goods from Amazon and other suppliers. For example:
Amazon.com: Polypropylene Fabric, Waterproof Fabric, Non-Woven Fabric, Disposable Waterproof Non-Woven Fabric 95% Thickened DIY Handmade Material Blue
(Hyperlink may not be working tonight.)
A first consideration has been protection of supplies for medical use and protection against infection. But lately there is so much of it being manufactured, some expressly not for medical use, that may not be an issue.
The next issue might be the performance of the ‘spun bonded’ material in tent canopies. So I dug out one of my used masks from the trash and found that it is an extremely strong material, even in very light weights. Amazon and some others also market it as ‘waterproof,’ and there are photos online of water being poured on it without effect. However, I’m not aware of any HH tests to see just how waterproof it is. It is not as water absorbent as nylon, but neither is polyester. So as your use of the term “silpolypropylene” suggests, I think methods for application of coatings would be necessary.
Also, as a devotee of woven fabrics for tents, I’d be more interested in coating a very light weight, high thread count olefin. The advantages of woven fabrics for tents have been discussed at great length on BPL by the forum moderator, Roger Caffin; so I won’t repeat them here, as it can be a lengthy discussion on a topic outside the scope of this thread.
For the time being, I think I’ll stick to silpoly, even if it means a small weight penalty compared to nylon. Because I’d like to live long enough to finish my next tent.