| 摘要 |
PURPOSE:To obtain the title tube good in adherability of the innermost layer, for e.g. processed meat food packaging use by encapsulating a gas into a multi- layered seamless tube with polyolefin resin layer as the innermost layer followed by crushing and by externally making a corona discharge treatment by a spe cific means. CONSTITUTION:A gas is encapsulated, between pinch rolls 2 and 3, into a multi- layered plastic seamless tube 1 having thermal shrinkability and gas barrier nature with polyolefin resin layer as the innermost layer, and in such a state as to be positively crushed with electrical insulating members 4 so as not to come into mutual contact of the innermost layers, a corona discharge is made so as to be in contact of electrode 6 of a pair of electrodes 5, 6 with the outer most layer of the tube and not to be in contact of the other electrode 5 with the outermost layer of the tube, thus forming a corona discharge part 8. Thence, another pair of electrodes 15, 16 is set up inversely to the above case, and a second corona discharge is made to form a second corona discharge part 18, thereby increasing the wetting tension of the innermost layer surface to >=35 dynes/cm, thus obtaining the objective corona-treated tube. |
