| 摘要 |
A multilayer non-irradiated film comprising a core layer, a respective further layer laminated to each side of the core layer, and an additive capable of migrating within the film, is prepared by: (i) blending an additive, such as a fungicide, encapsulated in a first thermoplastic resin, with a second thermoplastic resin which has a lower melting point than the first resin so that during extrusion of the blend the second resin melts and surrounds the encapsulated additive before the first resin melts; and (ii) coextruding the resulting blend to provide a layer, preferably the core layer, of the film and respective thermoplastics resins to provide the other layers of the film. Preferably a five layer film is formed in which a respective intermediate layer is provided between the core layer and each outer layer. A heat-shrinkable film may be formed by subsequently orienting the film. The film can be used to package articles such as fruit and vegetables to protect them from fungal infection. |
