The reason why BoPET and Mylar are heavily used by companies is because they have very versatile properties:
“Mylar and other BoPET films are used to make flexible packaging and lids for the food industry, such as yogurt lids, roasting bags, and coffee foil pouches. BoPET is used to package comic books and for archival storage of documents. It’s used as a covering over paper and cloth to provide a shiny surface and protective coating. Mylar is used as an electrical and thermal insulator, reflective material, and decoration. It’s found in musical instruments, transparency film, and kites, among other items.”² Don’t forget that emergency “space blanket” when camping, that’s made of Mylar too!