The ordinary definition a human being would provide. Something that is soft to the touch.
That doesn't leak more than 10% over at least a one-year period.
In PSI? I don't know what that would be. Probably about the same pressure inside a new tennis ball, but the pressure would be from the outside.
A boot is like something a human being wears on his feet when he goes places. A cuff is the upper area of the boot that surrounds the ankle. The term "boot cuff" used in sports like skiing and inline skating.
Compared to metals and glass, all plastics leak. Metalized Mylar PET balloons will hold helium for a long time vs rubber which will deflate in a few hours. If you can prepare a metalized or silicone dioxide surface, your problem will be solved. Some of the most leak retardant plastics used in food packaging are polyvinylidene chloride (Saran) and ethylene/vinyl alcohol copolymer. PET is 10X as permiable and PE 100X. DuPont had a PET foamed product called Pneumocel (sic) that was post inflated with a high molecular weight fluorocarbon gas where osmotic pressure of air trying to dilute the flourocarbon kept the foam inflated. It was used as a premium carpet underlay and would probably serve your purpose, but I doubt it is still available. Frank
A good example would be inflatable air cushions (back & side support and lumbar) in car and truck seats, some of which are made out of welded TPU-films and which need to function for a long time. Hytrel-type materials would also work for this application, if the US-welding issue could be overcome ...
"John Doe" schrieb im Newsbeitrag news:Xns97F71C9E5BEE20123456789@18.104.22.168...
It works so well as an aftermarket cushioning material I'm wondering why they don't use something like bubble wrap in the manufactured product. It would have to be much more durable and yet about as soft and the bubbles as small. And it could not leak over time, otherwise you would end up with limp boot cuff cushioning in an expensive boot. I'm also trying some of the high-quality bubble wrap as insole cushioning material. It will have to be periodically replaced but it's strong enough.
Looks like I had a hit there, but we seem to be back to your original question concerning a soft polymer with low air permeability!
Since I don't know your capabilities, let me try a few recommendations:
you get that "Bubble Wrap® Packaging" made out of an "extremly low air permeability TPU-Film" or the like see ->
you contruct your cushioning out of Butyl rubber, which is known to have very low air permeability see ->
or you get the "Bubble Wrap® Packaging", that you have been using successfully, coated with a suitable low air permeability elastomer like neoprene, silicone or TPU as this is done for air bag fabric cushions for the very same reason, see for example ->
or you search for another soluti> "Rolf Wissmann" wrote: