| 摘要 |
<p>There is described a flexible oriented film (301) which acts a replacement for tear film, the film (301) having at least one tear susceptible line (307, 309) or pattern thereon (preferably weaker than the surrounding film), the film tearing substantially therealong when tearing is initiated therealong, characterised in that the line (307, 309) or pattern has substantially the same thickness normal to the film surface (gauge) as the rest of the film; and/or the film material therealong is substantially differently (preferably more) oriented (in extent and/or direction) to that in the rest of the film. The means for forming the line (307, 309) or pattern is preferably a laser (e.g. infra-red CO2 laser) set at a sufficiently low power not to ablate material therealong but at a sufficiently high power to reorient the film therealong. A method of preparing such films (301) and packaging (721) (such as cigarette packs) overwrapped with such films (601) are also described.</p> |
