An unusual process commercialized in France three years ago produces lightweight structural polypropylene sheet with 80% lower density by creating micro-perforations through the sheet with water and vacuum.

An unusual process commercialized in France three years ago produces lightweight structural polypropylene sheet with 80% lower density by creating micro-perforations through the sheet with water and vacuum. The critical cooling and calibration technology (patent applied for) belongs to the processor, which prefers not to be identified. The equipment injects pressurized water through small holes on one side of the hot sheet and draws a vacuum on the other side, which opens small holes through the sheet. This reduces its weight without hurting impact strength, claims Mai Virginio Technology Srl, Buguggiate, Italy, which has supplied three extrusion lines for the process based on 140-mm, single-screw extruders. The micro-holes also create natural air circulation through the sheet. The product is sold as black and white panels up to 1.5 in. thick. Mai Virginio: +39 (332) 45 41 00, www.maivirginio.it