| 摘要 |
At least one surface of a polymeric film is plasma treated in a modified atmosphere comprising an inert carrier gas and a functional material. The plasma treated surface of the film is then contacted with a foil, such that the foil adheres to the polymeric substrate. The functional material comprises an oxidising fluid, a reducing fluid or a polar fluid with the capacity to form ionic or covalent bonds with the film substrate. The preferred modified atmosphere comprises a noble gas or nitrogen, and acetylene, ethylene, hydrogen, silane, ammonia, sulphur hexafluoride, oxygen, ozone, carbon dioxide, carbon monoxide, nitric oxide, nitrous oxide, sulphur oxides. The preferred contacting step involves hot foil stamping. The preferred film is biaxially oriented polypropylene (BOPP) and the preferred foil is aluminium or copper. The preferred process also involves opacification, embossing, etching, printing or overcoating. The plasma treatment is preferably an atmospheric pressure, modified atmosphere dielectric barrier discharge (MADBD) treatment using plasma torches. The film is used for security, authentication, identification and anti-counterfeiting measures for bank notes, credit cards, passports, certificates and packaging. |
