Hi Garrett, really good idea. Diapers are definitely not something that is interesting to recyclers, and asume they never will be. Do your diapers need any special conditions (temperature, moisture, additives, etc) to break down?
The idea is that the connecting ring that the cap is attached to is loose fitting, so it would rotate with the cap. The challenge now is making a good enough seal with a PET on PET closure and how to change the bottling lines to attach a cap by screwing it on rather than pressing it down.
Thanks for the input, I can see why this design would be a problem using conventional bottling machinery. I was thinking about maybe a different approach towards assembling the closures, one where the closure in the proposed model would be inserted underneath the preform (just the connecting ring) and the regular cap could be screwed/twisted into position. I would have to change the safety seal design because you are right about the PET being too brittle for this type of functionality. If the seal is still not good enough, we could look into some kind of liner, maybe LDPE, that could give us the seal we need but can easily separate from the PET during the recycling process in a simple sink/float step.
Really like your idea about the PET film closure, any idea regarding the thickness of the film needed to meet barrier requirements?