摘要 |
The present invention relates to a film made of holed plastic material three-dimensionally shaped, having an upper surface presenting a multiplicity of opening extending in the form of through holes (303) in the direction of a lower surface of the same film; mutually adjacent through holes (303) being separated by segments (301) of film having a profile in the shape of a conic section as a cross section with symmetric sides (304, 305) converging towards the upper surface. |