| 摘要 |
<p>PURPOSE: To improve printing properties and film making stability by bonding a porous support consisting of polypropyrene film and polypropyrene fiber together directly without using an adhesive, and specifying a separation strength between the film and the porous support. CONSTITUTION: Polypropyrene film is at least, uniaxially stretched, and an unwoven cloth is used as a porous support adhering firmly to the film. In order to bond these materials together directly without using an adhesive, a themal adhesion method is employed. When stretching preferably the polypropyrene film, the film and the porous support are thermally bonded together in a stage preceding the stretching process, and in the following stretching stage, are constretched. A thermal roll for thermal. pressure adhesion is employed as a themal adhesion means. The separation strength between the film and the porous support should be,at, least, 1g/cm, preferably, cm, at least, 30g/cm. If the separation strength is less than 1g/cm, the film peels off when transporting it, resulting in the generation of creases or breaks, so that the film cannot be prepared stably.</p> |
