Perforierter Film mit schräg-winkeligen Kapillaren

摘要

Perforated film from a polymer material in which the perforations are shaped as capillaries that extend from the surface of the film in non-vertical direction and are characterized by level walls. For producing such a perforated film a molten starting film is fed to a vacuum perforating device which has a cylinder or a strip with angular bores with level surface profile. The polymer melt is drawn in direction of the vacuum and the capillaries are formed by cooling the film.