| 摘要 |
PURPOSE: To obtain a thin film with high reliability and uniformity in thickness by laminating multiple undrawn thermoplastic film webs, and, after heat treatment, drawing the film webs, which are biaxially drawn film, to the thickness of a specific value (μm) or less. CONSTITUTION: To produce thin film, namely, biaxially drawn thermoplastic film webs, firstly at least two unstreatched thermoplastic film webs are laminated. Next, the film webs are subjected to a heat-treatment. Then, the film webs, which are biaxially drawn films, are drawn to the thickness of about 2μm or less. At this instance, the heat treatment is carried out at a temperature higher than the glass transition temperature of the thermoplastic film. The heat treatment is carried out for 60 seconds or less with a water bath, hot air, or a radiator. The film webs are drawn in both the longitudinal and transverse directions with an area-drawing ratio of 16 or more. The film web is a polymer of polyolefine, polyester, polyamide or the like. |
