Medium density, (0.934-0.95) polyethylene. Has higher stiffness, higher melting point and better water vapour barrier properties.
Metallised OPP film. It has all the good properties of OPP film, plus much improved oxygen and water vapour barrier properties, (but not as good as MET-PET).
Metallised PET film. It has all the good properties of PET film, plus much improved oxygen and water vapour barrier properties. However, it is not transparent. see also VMPET.
Moisture vapour transmission rate, usually measured at 100% relative humidity, expressed in grams/100 square inches/24 hours, (or grams/square meter/24 Hrs.) See WVTR.
Mylar is a registered trademark of the Dupont-Teijin Corporation. Is the industrial brand name for that corporation’s polyester (PET) film. Polyester film is a staple of multi-layer packaging for a wide variety of applications.