| 摘要 |
Multi-layer packaging film for package contg. prod. that degrades and generates unwanted degradation compsns. is produced using continuous in-line process. Process entails extruding a base layer (62), orienting it in the machine direction (66), coating it on one side with a liquid film layer (76) that acts to reduce the adverse effects of unwanted degradation compsns., and drying it (78), extruding a sealant coating layer (84) over the dried film layer coating to separate the product from it in the package eventually made, and subjecting the sealant-coated dried packaging film to a tenter process (86) to obtain full orientation and to reduce the thickness of the sealant layer to increase its permeability to the degradation compsn. . Pref. the extruded base layer is polypropylene. The base layer is coextruded with a bonding layer (64). |
