Actually, it is polyethylene, not polyurethane.
Who knows, HnF might get hot enough to melt the plastic coating?
I find that actual butcher produces a firmer bark than non-porus foil. I never have used freezer paper.
I just looked it up.
Polyethylene (LD) 325 deg f
Polyethylene (HD) 400 deg f
Jim - Another transplanted Texan
Former KCBS CBJ
Large and Medium Big Green Eggs , Black 18.5" WSM, Blue Weber Performer - Stainless, Green Weber OTG Kettle , Brinkmann SnP Pro, and a Stainless UDS. One retired Portable Kitchen grill.
Red Thermapen, Maverick ET-732, EdgePro Apex Sharpener.
Avatar is the original 1951 Weber Kettle