Opinions on this membrane storage box…

I recently received a watch shipped to me in this box. If you’re familiar with it, it uses two layers of polyurethane plastic to suspend the watch inside the hard plastic outer shell.



I did some poking around on the Net about the long-term safety of this kind of plastic in terms of prolonged contact with the materials of a watch, but aside from eventual yellowing of the plastic, have come up with nothing definitive.

So, would you feel comfortable with long-term storage using this material, or would you transfer it to another storage box? I understand polypropylene or polyethylene are better choices, and Bergeon makes similar boxes for the storage of small watch parts, but any info on this would be appreciated.

I would just save it for shipping. I don't see much value in having a watch sandwiched closely on both sides by any type of polymer film. Over time, plastics can degrade and additives can leach out.

There was discussion here on this type of container some time ago.
A user had suggested (or questioned) using them to store dials, much to the alarm of the population here.

The rationale for their use seems to be the need to keep delicate/fragile parts stored in an immovable position.
However, I think it's those sort parts that don't need to be touching a plastic film for longer than necessary.

Unless it can be proved beyond doubt that the plastic film is totally inert long term I wouldn't use one except for short term shipping.