Patent ID: 8110137

Claim:
A process for manufacturing a plastic-based cellular structure comprising: (a) continuously extruding parallel lamellae of a composition comprising at least one thermoplastic polymer (P) chosen from amorphous and semi-crystalline polymers through a die comprising a plurality of parallel slots; (b) subjecting spaces between two adjacent lamellae to an injection of a fluid (f) and to a vacuum on exiting the die and in successive alternations, the two sides of a same lamella being, for one side, subjected to the action of the fluid (f) and, for the other side, to the action of the vacuum, and inversely during the following alternation, in order to produce deformation of the lamellae and to weld them in pairs with formation, in a plane approximately parallel to the extrusion direction, of a cellular structure whose constituent cells extend in a plane approximately parallel to but in a direction transverse to the extrusion direction; (c) drawing the cellular structure obtained in (b) in a plane approximately parallel to but in a direction transverse to the extrusion direction, wherein the draw ratio transverse to the extrusion direction to which the cellular structure is subjected, expressed by the ratio of the final working width of the cellular structure after drawing to its initial width, is at least equal to 1.2/1.