PET Polyester Packaging Film
Polyester a/k/a " PET " is strong and has a high melt point. Extrusion melt temperatures are over 500 degrees F. this has ramifications for how it can be utilized including with dual ovenable.
Polyester is made in several thicknesses referred to as " gauges ". The gauge is expressed in terms of percent of a mil, or 100th of an inch. So a " 48 gauge " is 48 /100 of an inch; 96 gauge is a light 1 mil and so on.
Polyester film is a popular choice for the outer layer of laminations mainly because of the high heat resistance and stiffness for use in pouches. Most flow wrappers and vertical form/fill/seal VFFS machines have bare metal jaws. The theory is the inner layer melts without melting or distorting the outer layer. Low Density Polyethylene LDPE melts around 300 F, so there is a huge differential. Lamination of polyester to LDPE is the best choice for a beginner.