Method of treating inner surface of plastic tube with plasma

摘要

In plasma-treating the inner surface of a plastic tube, the invention provides a treating method which ensures stable treatment under readily operative conditions. The present invention relates to a method comprising the steps of placing a plastic tube inside an electrically insulating tube wherein the difference between the inner diameter of the insulating tube and the outer diameter of the plastic tube is equal to or less than 2 mm, letting a gas into the plastic tube, keeping the inner pressures of both tubes at a reduced pressure, applying a high voltage across electrodes disposed outside the electrically insulating tube to initiate and sustain discharge only inside the plastic tube and thereby plasma-treating the inner surface of the plastic tube.