| 摘要 |
<p>PURPOSE:To obtain a film which is transparent, capable of keeping high gas barrier properties for a long period of time and favorable as a packaging material, by laminating transparent plastic films, which are superior in water-vapor barrier properties, on both sides of a polyvinyl alcoholic film to which specific treatment has been applied. CONSTITUTION:A polyvinyl alcoholic film is stretched within a magnification range of 5-10 at least in a monoaxial direction and the same to which heat treatment has been applied within a temperature range making the stretching temperature of the film as the lower limit and the fusion point of base resin as the upper limit is prepared. In succession to the above, the polyvinyl alcoholic film is dried so that a moisture content contained into the film becomes less than 1%; immediately transparent films which are superior in water-vapor barrier properties are laminated on both sides of the film and a transparent laminated film superior in gas barrier properties is obtained. As the plastic film superior in the foregoing water-vapor barrier properties, for example, a film of polyvinylidene chloride or polytetrafluoroethylene or a vinylidene coated film obtained by coating a polypropylene film or a polyethylene film with vinylidene chloride resin is used.</p> |
