Ethylene-Vinyl Alcohol copolymer, used in co extruded plastic films to improve oxygen barrier properties. It is, however, a poor water vapour barrier. Even its otherwise excellent OTR, (oxygen transmission rate) is sensitive to high humidity, therefore, for packaging applications, it is usually the core layer of co extruded plastic films, where it is shielded from moisture by protective layers of polyethylene. Its OTR also depends on its VOH (vinyl alcohol) content. ill and Seal Mac hines - Packaging machines which combine the functions of filling and closing in one machine. Fla t -Bottom Stand-up Pouch - a stand-up pouch that is made from one piece of film. The front, gusset, and back are continuous, so there is no seal at the gusset. Holds more weight than Doy-style pouches, so are commonly used for heavy products. Fl exo - Flexography Printing - Method of printing on a web press using rubber or plastic plates with raised images. Also called aniline printing because flexographic inks originally used aniline dyes. Abbreviated flexo.