METHOD FOR OBTAINING A PREGUE ON A SHEET OR IN A TUBULAR PECE OF PLASTIC MATERIAL, IN PARTICULAR IN THE EVENT OF A TUBE, AND TUBE SO OBTAINED

摘要

The subject of the invention is a process for obtaining a fold in a plastic sheet or tubular part (1) of 0.25 to 0.8 mm thickness, characterised in that at least one folded portion of the said sheet or a longitudinal portion of the said tubular part is rolled between rolls (2, 3) gripping the said portion so as to obtain a fold crushed by this rolling having at its apex an external depth reduction lying between 2% and 15% of the said thickness, this fold then being elastically articulated. This concerns in particular the preform of the flexible skirt of a tube, and the tube so obtained. The invention is applicable to flexible tubes packaging various products, the pressings of these tubes and their shape returning being improved. IMAGE