Stretched polychlorotrifluoroethylene film, process for the production thereof and packaged product using the film

摘要

A stretched PCTFE (polychlorotrifluoroethylene) film is provided with a good moisture-proofness (low moisture permeability) even at a relatively small thickness and at a small crystallinity The film is characterized by a crystallinity A (%) of 15-75% and a moisture permeability B (mg/m.sup.2.day) at a film thickness of 20 &mgr;m, satisfying a relationship of B/(100-A)≦3.0. The film may suitably be produced through a process characterized by a sequence of a relatively low-temperature melt-extrusion and a low temperature stretching. The film is suitably used for constituting moisture-proof packaged products, such as an EL device or a packaged drug product.