soft airtight material?

Is there such a thing as a soft airtight material that does not leak over time so it could be used as cushioning in a boot cuff?

Is there any example of a soft airtight material used in a manufactured product that works under pressure and does not leak over time?

Thank you.

Reply to
John Doe
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You need to provide much more information.

How soft is soft? How airtight is airtight? How much pressure?

And what exactly is a boot cuff? Why does it need to be cushioned?

John Aspen Research, -

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"Turning Questions into Answers"

Opinions expressed herein are my own and may not represent those of my employer.

Reply to
john.spevacek

Or you could give me some examples.

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.

Because.

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Reply to
John Doe

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

Reply to
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@207.115.17.102...

Reply to
Rolf Wissmann

How long before they have to be inflated again?

What I'm talking about is soft and small approximately 1/4" diameter air pockets that would be under pressure and would not be re-inflatable.

Thanks to the replies.

Reply to
John Doe

They would only need to be inflated or deflated again for adjusting the seat comfort. Should have mentioned that those TPU-films are co-extruded with glass mats in order to eliminate creep.

That's very small indeed! Reminds me of Bubble Wrap® Packaging material

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but I am not sure its air tight enough for your purpose. You'd need to contact those Bubble Wrap producers. Perhaps they can provide something for you ...

Reply to
Rolf Wissmann

That's what I'm using.

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.

Reply to
John Doe

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:

  1. you get that "Bubble Wrap® Packaging" made out of an "extremly low air permeability TPU-Film" or the like see ->

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  1. you contruct your cushioning out of Butyl rubber, which is known to have very low air permeability see ->
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  2. 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 ->

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  1. or you search for another soluti> "Rolf Wissmann" wrote:
Reply to
Rolf Wissmann

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Butyl rubber has the best air retention of all the soft materials.

Jim Coffey "original creator of the sci.polymer newsgroup and faq"

Reply to
jimcoffey62

Perhaps metallized buble wrap? I should be fairly easy to charge the bubble wrap surface and use metal ion deposition to coat the product as thick or thin as needed.

Reply to
Joseki

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