| 摘要 |
<p>Security films of the type used to make tamper-evident adhesive tape, also methods and apparatus for making the films. A polymer substrate film (10) e.g. of HDPE, is plasma treated while passing over a roller (6). Corona discharge is generated between a discharge electrode (4) and the roller (6). The roller (6) has a conductive external surface (14) with a relief pattern or cut pattern constituting an array of indicia (26) such as the word "VOID". The roller surface may be a layer of conductive polymer, laser cut to make the pattern. No plasma forms on the outer surface in pattern regions (22) where the roller surface (14) is recessed, so a subsequently applied coloured polymeric ink layer (38) adheres poorly in those regions. An adhesive layer (44) and protective release layer (46) are applied over the ink layer.</p> |
