PROCESS FOR MODIFYING MULTI-LAYERED PLASTIC FILM SEAMLESS TUBE

摘要

The invention relates to a process for modifying the surface of the innermost layer of a multi-layered plastic film seamless tube provided with the innermost layer composed of a polyolefine resin and having a gas barrier property by corona discharge treatment, characterized in that the wet tension of the surface of the innermost layer of the tube is increased to 35 dynes/cm or above by subjecting the tube to corona discharge treatment from outside with at least two pairs of corona discharge electrodes while flattening the tube by pressing in such a manner that the opposed surfaces of the innermost layer do not come into contact with each other by incorporating a gas inside the tube, and that one electrode of each of said two pairs of the electrodes is in contact with the outermost layer of the tube while the other electrode thereof is out of contact with said outermost layer, and one electrode of one pair of the electrodes is placed to be in contact with the outermost layer of the tube which is out of contact with one electrode of the other pair of the electrodes.