Process for the joint thermal sealing of at least two films of heat-shrinkable polymeric material, sandwich of heat-sealable polymeric material, sandwich of film-material, bag of heat-sealable polymeric material, and, heat-sealing device.

摘要

"PROCESS FOR THERMAL SEALING SET OF AT LEAST TWO FILMS OF HEAT RETRACTABLE POLYMERIC MATERIAL, SANDWICH OF HEAT-SEALING POLYMERIC MATERIAL, SANDWICH OF FILM MATERIAL, POLYMERIC MATERIAL BAG. Apparatus for polymeric thermal sealing purposes that shrink when heated includes the provision to move the zone of application of heat and pressure during the process of thermal sealing. This allows heat shrinkage of the polymeric film in a region adjacent to the heat seal so that the film thickens and is more resistant to failure in use through the peel. The apparatus includes a pair of sealing bars (4, 5), one of which (4) is wedge-shaped and the other (5) is flat. Both bars are heated and one of them can move in direction (12) to apply pressure to the film located between the bars. At the beginning of the heat sealing step, pressure is applied in an initial zone along the apex of the wedge. Subsequently, the bar (4) is wound around the axis located near the apex of the wedge, in the direction shown by the termination to the right of the arrow (13), to apply heat and pressure in a wider area located adjacent to the initial zone.