ABSTRACT
In general, plastic films as produced by the various processes described in Chapter 2 do not possess all of the properties required for demanding applications such as food packaging. Exceptions include most applications for shrink films and for blister and skin packaging as well as pouches from cast or blown films for non-food applications. However, many of these less demanding applications require surface printing and plastic films, generally, have relatively inert surfaces that do not provide sufficient adhesion to printing inks. Therefore, some kind of surface treatment is required. For food applications, gas barrier greater than most plastic films can offer is often required, so a layer of high barrier polymer is added. For the oriented films in particular, the ability to form a heat seal must be added by using a layer with a lower melting point.
