01-19-2025, 01:42 PM
RAMd®d wrote:
I don't know if the thickness of the bags affects the ingress of air/frost, or if it just holds up better against abrasion, being moved around in a freezer that doesn't defrost.
It makes a difference. People think of plastic as air and water tight, but thin films of polyethylene and some other plastics have micro-pores. Over time air or water can slowly pass through the film. So the thicker film used in regular ziplock bags compared to sandwich bags helps, and the bags made for freezer use are even thicker.
Another example is the thin walls of PETE bottles. PETE absorbs water, it can then slowly evaporate from the exterior surface. Over time that is enough to partially crumple an unopened bottled water for example. For some liquid products the makers will line the PETE bottles with a thin film of a different material that doesn't absorb water to keep it from transpiring through the PETE.
Polypropylene used in making Tupperware and similar containers is more air and water tight. It then comes down to how well the container and its lid seal are made.