Method and extrusion die for making a structuring fabric
An extrusion die makes a structuring fabric which has structuring-beads resting on sublayer-beads. The extrusion die has a flat first surface and a flat second surface, the first and second surfaces contact each other along a contact line. The first and second surfaces are inclined with respect to each other. The first surface has a first nozzle of a pair of nozzles for extruding a sublayer-bead and the second surface has a second nozzle of the pair of nozzles for extruding a structuring-bead on top of the sublayer-bead. The first nozzle has a substantially rectangular shape and the second nozzle has a shape that resembles a square with all four side edges bulged inwardly. Both the first nozzle and the second nozzle are located in close proximity to the contact line. The first nozzle has a first symmetry axis that is perpendicular to the contact line.
1 . An extrusion die for making a structuring fabric having structuring-beads resting on sublayer-beads, the extrusion die comprising:
a substantially flat first surface; and
a substantially flat second surface, said substantially flat first surface and said substantially flat second surface contacting each other along a substantially straight contact line and said substantially flat first surface and said substantially flat second surface being inclined with respect to each other;
said substantially flat first surface containing a first nozzle of a pair of nozzles for extruding a sublayer-bead and said substantially flat second surface containing a second nozzle of said pair of nozzles for extruding a structuring-bead on top of said sublayer-bead;
said first nozzle having a substantially rectangular shape and said second nozzle having a shape that resembles a square with all four side edges bulged inwardly, and both, said first nozzle and said second nozzle being disposed in close proximity to said contact line;
said first nozzle having a first symmetry axis that is perpendicular to said contact line, said second nozzle having a second symmetry axis that is perpendicular to said contact line, and the first symmetry axis and the second symmetry axis contacting each other directly at said contact line.
2 . The extrusion die according to claim 1 , wherein a distance of said first nozzle to said contact line is smaller than 10% of a dimension of said first nozzle measured along the first symmetry axis and/or wherein a distance of said second nozzle to said contact line is smaller than 10% of a dimension of said second nozzle measured along the second symmetry axis.
3 . The extrusion die according to claim 1 , wherein said first nozzle has a third symmetry axis that is parallel to said contact line and wherein said second nozzle has a fourth symmetry axis that is parallel to said contact line.
4 . The extrusion die according to claim 3 , wherein a dimension of said first nozzle measured along the third symmetry axis substantially corresponds to a dimension of said second nozzle measured along the fourth symmetry axis.
5 . The extrusion die according to claim 1 , wherein a dimension of said first nozzle measured along the first symmetry axis substantially corresponds to a half of a dimension of said second nozzle measured along the second symmetry axis.
6 . The extrusion die according to claim 1 , wherein a dimension of said second nozzle measured along the second symmetry axis is between 60% and 80% of a largest dimension of said second nozzle measured along a line that is parallel to the second symmetry axis.
7 . The extrusion die according to claim 1 , further comprising a plurality of equally formed pairs of nozzles that are distributed along said contact line.
8 . The extrusion die according to claim 1 , further comprising a common supply chamber, said first nozzle and said second nozzle are connected to said common supply chamber within the extrusion die so as supply a same material to both said first and second nozzles.