| 摘要 |
PURPOSE:To obtain the title tube improved in adhesion to packed food by sealing a gas in a seamless tube made of a multilayered plastic film having a polyolefin resin layer as the innermost layer, collapsing the tube in such a manner that the innermost layers are not brought into contact with each other and conducting the corona discharge treatment of the tube. CONSTITUTION:A gas is sealed in a seamless tube 1 made of a multilayered plastic film comprising a polyolefin resin layer as the innermost layer and having heat shrinkability and gas barrier properties, and this tube is continuous ly moved along the direction shown by the arrows by pinch rolls 2, 2 and 3, 3 to be fed in between each of two pairs of corona discharge treatment electrodes: roll discharge electrodes 4 and 14 and electrodes 5 and 15 having an air blowing means, collapsed so that the distance between the innermost layers of the tube 1 may be 5mm or below and that the layers may be kept out of contact and subjected to corona discharge treatment from the opposite directions to give a wet tension >=35dyn/cm to the innermost layer surface. |
