Screen for producing a perforated film

摘要

A cylindrical screen for perforating a thermoplastic film or sheets has an outer surface and an inner surface. A plurality of outer apertures extend from the outer surface and terminate at a corresponding inner aperture on the inner surface of the screen. The apertures in the outer surface can have the same or a different geometrical shape as the apertures in the inner surface. The apertures form a passageway through the screen. The passageways are disposed at least one angle from about 5 DEG to about 60 DEG with respect to a plane that is disposed substantially perpendicular to the outer surface of the screen to prevent a direct line of sight through the screen.