Method for manufacturing a seat cushion and seat cushion as such
View Patent ↗The present disclosure relates to a method for manufacturing a seat cushion comprising: providing a cushion comprising a 3D entanglement of continuous thermoplastic fibers, arranged irregularly or randomly forming loops heat-sealed together and hot-pressing of the 3D entanglement of fibers into one or more local 3D entanglement areas so as to obtain one or more densified, stiffened local areas of the cushion, the local area(s) being configured to serve as a fastening area. The present disclosure also relates to a cushion obtained according to the manufacturing method, and a seat comprising such a cushion and a cap attached to the densified, stiffened local area(s).
1 . A method for manufacturing a seat cushion comprising:
providing a cushion comprising a 3D entanglement of continuous thermoplastic fibers, arranged irregularly, forming loops that are heat-sealed to one another, and hot-pressing of the 3D entanglement of fibers into one or more local 3D entanglement areas so as to obtain one or more densified, stiffened local areas of the cushion that are denser and stiffer than the other area of the cushion, the local area(s) being configured to serve as a fastening area.
2 . The method of claim 1 , wherein the providing step includes:
extruding a thermoplastic polymer in an extrusion die comprising extrusion nozzles distributed in a lengthwise direction and along a widthwise direction of the extrusion die, generating a curtain of continuous molten fibers, falling by gravity,
receiving the curtain of continuous molten fibers falling by gravity on one or more support elements with a 3D entanglement of fibers being generated according to an irregular distribution with loops melting between the continuous fibers, and/or
solidifying the 3D entanglement of fibers by immersion in a cooling liquid.
3 . The method of claim 1 , wherein the hot pressing in one or more local areas of the cushion leads to a compression by partially reducing the thickness of the 3D entanglement into the local area, by at least 30% according to the thickness.
4 . The method of claim 1 , wherein in the pressing is a thermoforming step during which a first mold part and a second mold part transform the fibers of the 3D entanglement of the local area into two elastic lips, including:
a first lip adjoining the entanglement at the local area by a first proximal end and has a first free distal end and
a second lip adjoining the entanglement at the local area by a second proximal end and has a second free distal end,
and wherein the first lip and the second lip are oriented towards each other, forming a first snap-fitting part configured to insert a second snap-fitting part into a slot delimited between the first and second distal ends belonging to the first lip and to the second lip.
5 . The method of claim 1 , wherein in the pressing is a thermoforming step during which a first mold part and a second mold part transform the fibers of the entanglement of the local area into a fastening element, such as a tie rod, the fastening element extending transversely to the local area, adjoining the 3D entanglement of thermoplastic fibers by two ends of the fastening element.
6 . The method of claim 1 , wherein in, the pressing generates a through slot along the thickness, from one face of the cushion, to an opposite face.
7 . The method of claim 1 , wherein in the pressing is a thermoforming step partially reducing the thickness of the 3D entanglement by densifying the fibers of the entanglement of the local area with preservation of the 3D entanglement loops heat-sealed together in the local area.
8 . The method of claim 1 , having all or some of the following features
the fibers are hollow fibers and/or solid fibers, with a diameter of between 0.2 mm and 2 mm,
the fibers comprise a thermoplastic polymer, the composition of the fibers comprising at least 95% by weight of PET,
and wherein the 3D entanglement of the cushion has an apparent density of between 45 kg/m 3 and 65 kg/m 3 on said other area that is less dense and less stiff than the densified, stiffened local areas.