The process of manufacturing a mattress, and the mattress itself.

Abstract

This disclosure relates to a method for manufacturing seat padding comprising: - / A / Supplying a padding (MAT) comprising a 3D entanglement of continuous thermoplastic fibers arranged irregularly forming loops welded together, - / B / Pressing the 3D fiber entanglement into one or more local zones of the 3D entanglement so as to obtain one or more local zones (ZL) of the padding, densified and stiffened, the local zone(s) being configured to serve as a fixing zone,resulting in compression through a partial reduction of the thickness of the 3D entanglement in the local area, characterized in that in / B / the pressing is an operation during which a first tooling element and a second tooling element come from either side of the 3D entanglement of thermoplastic fibers to compress and weld the fibers of the 3D entanglement in the local area and transform the thermoplastic fibers into an annular bead (BA). Abstract figure: Figure 1,

Description

Title of the invention: Method for manufacturing a mattress, and mattress as such

[0001] This disclosure relates to a method for manufacturing padding, as well as to seat padding as such, which can be obtained by the method.

[0002] The present disclosure is still related to a set of padding. technical field

[0003] The present disclosure falls within the domain of devices and techniques for fixing a headgear onto padding. Previous technique

[0004] Seat cushions are typically made substantially of urethane polymer foam (or polyurethane, PU), in particular polyurethane foam obtained from polyether / polyol (or PUR) type polyols. Such foams can be shaped in molds relatively easily to form different cushion shapes for various vehicle seat components, such as the seat cushion and backrest, for example.

[0005] It is also known to incorporate fasteners, such as rods, into the mold as inserts. These fasteners allow, in particular, the attachment of a headgear to be fixed to the padding by clipping onto the insert fasteners.

[0006] Polyurethane foam padding is satisfactory, but can retain moisture, particularly in humid conditions. This can cause discomfort for an occupant of a vehicle seat containing such padding.

[0007] Furthermore, polyurethane foam is conventionally produced by mixing, among other things, polyols with isocyanates. The chemical reaction carried out emits CO2 to form a foam, and the emitted CO2 contributes to global warming.

[0008] Furthermore, polyurethane foam is not recyclable. Therefore, at the end of their life, the seats are dismantled and sorted to separate the recyclable components from the non-recyclable ones. The recyclable components are then ground up to form a new raw material, while the non-recyclable components are typically landfilled or, if possible, incinerated to generate energy.

[0009] However, prior art, in particular application FR 3,139,025 A1, is known, a padding formed from a 3D entanglement of continuous fibers, Irregularly arranged to form loops welded together, this material is breathable and less CO2-intensive to manufacture. The fasteners typically used as inserts in polyurethane foam padding are not compatible with this 3D entanglement of continuous fibers.

[0010] Application FR 3.139.025 Al teaches how to densify and stiffen local areas of the 3D entanglement to allow the attachment of a cap to the padding, and according to various techniques.

[0011] According to the findings there is a need for other fastening systems suitable for attaching a headgear to padding, and in particular to padding formed from a 3D entanglement of continuous fibers. Summary

[0012] This disclosure improves the situation.

[0013] A method for manufacturing seat padding is proposed, comprising: - / A / Supplying padding comprising a 3D entanglement of continuous thermoplastic fibers arranged irregularly, forming loops welded together, - / B / Pressing the 3D fiber entanglement into one or more local areas of the 3D entanglement so as to obtain one or more local areas of the padding, densified and stiffened, the local area(s) being configured to serve as a fixing area, resulting in compression by a partial reduction of the thickness of the 3D entanglement in the local area.

[0014] According to this disclosure, in / B / the pressing is an operation in which a first tooling element and a second tooling element come from either side of the 3D entanglement of thermoplastic fibers to compress and weld the fibers of the 3D entanglement of the local area and transform the thermoplastic fibers into a bead, annular, in particular of closed trajectory, in particular circular, ovoid, polygonal, in particular rectangular, the annular bead adjoining the fibers of the entanglement on an outer periphery of the annular bead, and in which the annular bead defines an internal fixing orifice.

[0015] The features described in the following paragraphs may optionally be implemented independently of each other or in combination with each other:

[0016] According to one embodiment, the first tooling element and the second tooling element respectively comprise an ultrasonic sonotrode and a support, wherein in / B / the sonotrode and the support are positioned on either side of said entanglement, the sonotrode being set into vibration at a frequency typically between from 20 kHz to 70 kHz to achieve the welding of the thermoplastic fibers together and form said annular bead.

[0017] In particular, the sonotrode includes a shaped end forming an annular groove which, by complementarity of form with the support, forms in / B / , said annular ridge.

[0018] According to one embodiment, the process has between / B / and / A / an intermediate step of thermoforming the 3D entanglement of fibers of the padding generating a deep groove in a surface of the padding intended to receive the occupant of the seat, and in which at / B / the first tooling element and the second tooling element come to compress and weld the thermoplastic fibers between a bottom of the groove and a surface opposite to the surface intended to receive the occupant of the seat, and so that the annular bead is formed on a bottom of the groove.

[0019] According to one embodiment, the supply step / A / comprises: - / Al / Extrusion of a thermoplastic polymer in an extrusion die comprising extrusion nozzles distributed along a longitudinal direction and along a widthwise direction of the extrusion die, generating a curtain of continuous molten fibers, falling by gravity, - / A2 / Reception of the curtain of continuous molten fibers falling by gravity from the calendering units, generating a 3D fiber entanglement with an irregular distribution and fusion of loops between the continuous fibers - / A3 / possibly solidification of the 3D fiber entanglement by immersion in a coolant.

[0020] The present disclosure further relates to a seat cushion that can be obtained according to the process described in this disclosure, comprising a 3D entanglement of irregularly arranged continuous thermoplastic fibers, forming loops welded together between the fibers, and wherein: - the fibers are hollow and / or solid fibers, in particular with a diameter between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm, - the fibers comprise a thermoplastic polymer, the cushion comprising one or more localized areas densified and stiffened by hot pressing of the 3D entanglement and wherein the 3D entanglement of the padding has an apparent density between 20 kg / m3 and 70 kg / m3, in particular between 45 kg / m3 and 65 kg / m3, outside the densified and stiffened local area(s), and wherein the padding includes at least one densified and stiffened area comprising at least one annular bead adjoining the fibers of the 3D entanglement on an outer periphery of the annular bead, said at least one annular bead defining an internal fixing opening in said annular bead.

[0021] According to one embodiment, said 3D entanglement of fibers having a groove in depth of a surface of the padding intended to receive the occupant of the seat, and in which said at least one annular bead is formed on the bottom of the groove.

[0022] This disclosure further relates to a padding assembly comprising a seat cushion according to this disclosure and a cover attached to the cushion by at least one fastening element, in particular an elastic one, fixed in said at least one fastening opening of the annular bolster, in particular by elastic interlocking. The shape of the fastening element may be adapted, preferably complementary, to a cross-section of the fastening opening.

[0023] According to one embodiment of said assembly, in particular for a fastening orifice with a circular cross-section, said fastening member comprises a rod extended by a fork having two elastic arms ending in a truncated cone, said truncated cone split by a slot separating the two elastic arms, the slot separating the truncated cone into two halves of a truncated cone, the split truncated cone having a small base, at a terminal end of said fastening member, smaller in size than a cross-section of said fastening orifice, and a large base adjoining the two arms of the fork, the large base being larger in size than said cross-section of said fastening orifice, in a rest position of said fastening member, and the large base being smaller in size than the cross-section of said fastening orifice,in a constrained position of said fastening member in which the two halves of the truncated cone are elastically brought together, and in which said fastening member is configured to be fitted into said fastening orifice of the annular bead, by insertion of the split truncated cone, during which the frustoconical wall of the split truncated cone in contact with the bead constrains said fastening member in the constrained position in which the two halves of the truncated cone are brought together, allowing passage of the large base through said fastening orifice, then an elastic return of said fastening member to the rest position ensuring a locking of said fastening member against the annular bead by support of the large base against the bead,in the rest position of said fastening member. The truncated cone may be replaced by a truncated pyramid in the case where the cross-section of the fastening orifice is rectangular, namely that the slot separates the split truncated pyramid into two halves of truncated pyramids.

[0024] According to one embodiment, the padding material and the material of said elastic organ are in a thermoplastic polymer whose main chain repeating pattern includes the ester function and optionally the ether function.

[0025] The present disclosure further relates to a method for recycling a padding assembly according to the present disclosure, wherein the padding material and said fastening member is a thermoplastic polymer whose main chain repeating motif comprises the ester function and optionally the ether function, comprising: - optionally, separation of the headgear from the padding assembly, - grinding of the padding and said fastening element attached to the padding, for the production of granules - the use of the granules for the manufacture of a plastic product based on a thermoplastic polymer whose main chain repeating pattern includes the ester function and possibly the ether function, in particular by molding or extrusion. Brief description of the drawings

[0026] Other features, details and advantages will become apparent from reading the detailed description below and from analyzing the accompanying drawings, in which: Fig. 1

[0027] [Fig. 1] is a cross-sectional view of a padding assembly comprising a padding and a cap attached to the padding, the padding being formed of a three-dimensional (3D) entanglement of continuous thermoplastic fibers forming loops welded together, said 3D entanglement comprising a densified local area of ​​said 3D entanglement comprising an annular bead, the annular bead being obtained by compression and welding of the thermoplastic fibers together, the annular bead adjoining the figures of said entanglement on the periphery of the annular bead, said annular bead defining a fastening opening, through which passes an elastic fastening member, comprising a rod integral with the cap, the rod extended by two forked prongs, and a truncated cone, split by a slit separating the two prongs of the fork, as well as the cone hole in two truncated cone halves, the truncated cone comprising a small base,of smaller dimensions than said fixing orifice, and a larger base, in a resting position of said fixing member, the larger base forming a support on the ridge opposing the extraction of said fixing member. Fig. 2

[0028] [Fig.2] is a series of views comprising: - at the bottom right, a seat cushion formed from a 3D interweaving of thermoplastic fibers comprising a central part and two raised lateral parts, a first groove separating the central part and the left lateral part, and a second groove separating the central part and the right lateral part, annular bolsters distributed along the first groove and annular ridges distributed along the second groove, - at the top, a detail and cross-section view of the padding according to the view on the right, including the left groove, on a top surface of the 3D entanglement of thermoplastic fibers, the bottom of the groove having three annular ridges, distributed along the padding, arranged on the bottom of the groove, - at the bottom left a detail view of the ridge. Fig. 3

[0029] [Fig.3] is a perspective view of an ultrasonic sonotrode whose end vibrating, features an annular groove configured to form the annular ridge. Fig. 4

[0030] [Fig.4] is a cross-sectional view along one axis of the sonotrode. Fig. 5

[0031] [Fig.5] schematically illustrates: - on the left, an annular ridge provided with said fixing orifice, said orifice delimited by the internal diameter and a fixing member, comprising a rod intended to be integral with the cap, extended by two elastic branches of a fork, and a truncated cone, comprising two halves respectively integral with the elastic branches, separated by the slit, - on the right, a cross-sectional view illustrating said fastening element attached to the annular bead by the support of the large base of the truncated cone against the annular bead. Fig. 6

[0032] [Fig.6] is a view of the padding supply in the form of an entanglement 3D of continuous fibers and according to / A / of the process according to this disclosure. Fig. 7

[0033] [Fig.7] is a successive view of [Fig.6] illustrating the pressing of the padding, between a first tooling element and a second tooling element, respectively an ultrasonic sonotrode whose end is shaped with an annular groove, and a support. Fig. 8

[0034] [Fig.8] is a successive view of [Fig.7]. Fig. 9

[0035] [Fig.9] is a view of a method of manufacturing the padding by extrusion of thermoplastic fibers, including fiber accumulation to obtain an irregularly arranged continuous fiber tangle forming loops welded together, and solidification of the continuous fiber tangle in a coolant Description of the implementation methods

[0036] This disclosure relates to a method for manufacturing seat padding comprising: - / A / Supply of a MAT padding comprising a 3D entanglement of continuous thermoplastic fibers arranged irregularly, forming loops welded together, - / B / Pressing the 3D fiber entanglement into one or more local zones of the 3D entanglement so as to obtain one or more densified and stiffened local ZL zones of the padding, the local zone(s) being configured to serve as a fixing zone, resulting in compression by a partial reduction of the thickness of the 3D entanglement in the local zone.

[0037] Generally, the fibers of the 3D entanglement, typically polyester-based, can be hollow and / or solid fibers. The fibers can have a diameter between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm. The term "continuous" in "continuous fibers" refers to fibers whose length is much greater than their diameter, and due to the manufacturing process, which is described below, typically by a ratio of at least 100, or even 500, or even 1000.

[0038] The 3D entanglement of continuous fibers can have an apparent density between 20kg / m3 and 70 kg / m3, in particular between 45 kg / m3 and 60 kg / m3, preferably between 35 and 70kg / m3, outside of local densified areas.

[0039] For example, the composition of the fibers, or even of the padding, includes: - 95% to 99% by weight of a first polymer from the polyester family such as PBT (Polybutylene terephthalate), - 1% to 5% by weight of a second polymer from the polyester family such as PTT (Trimethylene Polyterephthalate) or another polyester.

[0040] Often, and especially as can be understood from the extrusion manufacturing process which will be described below, the fibers typically extend from a first end on a first edge of the 3D entanglement and to a second end on a second edge of the 3D entanglement, opposite to the first edge.

[0041] Preferably, the voids between the fibers of the 3D fiber entanglement of the first layer 31 of the padding are left free. This results in a highly breathable padding, due to the numerous inter-spaces between the fibers which promote air circulation, and in contrast to a molded polyurethane body, which is closer to an air-impermeable body, comparatively.

[0042] The padding may be, but not limited to, seat padding, in particular seat padding, or backrest padding, armrest padding, or any other seat padding.

[0043] According to this disclosure, in / B / the pressing is an operation in which a first tooling element OT1 and a second tooling element OT2 come from either side of the 3D entanglement of thermoplastic fibers to compress and weld the fibers of the 3D entanglement of the local area, and as schematically illustrated in [Fig.7].

[0044] The first tooling element and the second tooling element transform the thermoplastic fibers into an annular bead, BA. An annular bead BA is defined as a bead that extends along a closed path. The path of the bead can be circular or of another shape such as ovoid, polygonal, for example square, rectangular, hexagonal...

[0045] In particular, and as illustrated in [Fig.7], the first tooling element OT1 and the second tooling element OT2, when applied under pressure to the padding, comprise: - opposing surfaces forming, through complementary shapes, an annular groove GA ensuring molding of the annular bead BA, - a peripheral opening OP, extending around an axis of the annular groove, ensuring that the annular ridge BA remains attached to the fibers of the entanglement on an outer periphery of the annular ridge BA, and preferably on the entire periphery.

[0046] The annular bead BA defines an internal fixing orifice OF, passing through the annular bead BA. This fixing orifice OF is obtained in / B / , or in a subsequent step by a material removal if a layer of material remains after / B / .

[0047] According to one embodiment, the first tooling element OT1 and the second tooling element OT2 may respectively comprise an ultrasonic sonotrode and a support.

[0048] In / B / , the sonotrode and the support are positioned on either side of said entanglement, the sonotrode being vibrated at a frequency typically between 20 kHz and 70 kHz to achieve the fusion of the thermoplastic fibers together and form said annular bead BA. According to one embodiment, the sonotrode comprises a shaped end forming the annular groove GA which, by complementarity of shape with the support, forms said annular bead BA in / B / .

[0049] In general, / B / allows the formation of an annular bead BA, in the thermoplastic material of the fibers which are entirely compressed and welded together.

[0050] The annular BA bead can be circular, as seen in the illustrated embodiments, or ovoid in shape (not illustrated), or polygonal, or rectangular.

[0051] The annular BA bead, particularly when circular, may comprise the following dimensions: - an external diameter (Dext) between 10 mm and 18 mm, - an inner diameter Dint between 3 mm and 6 mm, - a height h between 3 mm and 8 mm.

[0052] The internal OF fixing orifice may have the same shape as the shape of the annular bead BA, namely: - a circular section when the geometry of the annular bead BA is circular, - an ovoid section when the geometry of the annular bead BA is ovoid in shape. - a polygonal section, in particular rectangular or square, when the geometry of the bead is polygonal, in particular rectangular or square.

[0053] According to one embodiment, the process may have between / B / and / A / an intermediate step of thermoforming the 3D entanglement of fibers of the padding generating a groove RA deep into a surface of the padding intended to receive the occupant of the seat.

[0054] In / B / the first tooling element OT1 and the second tooling element OT2 then compress and weld the thermoplastic fibers between a bottom of the groove RA and a surface opposite to the surface intended to receive the occupant of the seat, and so that the annular bead BA is formed on a bottom of the groove RA.

[0055] In general, the supply step / A / may include: - / Al / Extrusion of a thermoplastic polymer in an FE extrusion die comprising extrusion nozzles distributed along a longitudinal direction and along a widthwise direction of the extrusion die, generating a curtain of continuous fused RD fibers, falling by gravity, - / A2 / Reception of the continuous molten fiber curtain falling by gravity from the calendering units RC1, RC2, generating a 3D fiber entanglement with an irregular distribution and fusion of loops between the continuous fibers - / A3 / possibly solidification of the 3D fiber entanglement by immersion in an LF coolant.

[0056] Reference is now made to [Fig. 9], which represents an example of a method for manufacturing the padding. The method comprises extruding a thermoplastic polymer, in particular a thermoplastic polymer as defined above, through an FE extrusion die of the installation. The FE extrusion die can, in particular, be fed with granules of thermoplastic polymer, in particular a thermoplastic polymer as defined above, for example from a recycling process.

[0057] The extrusion die FE comprises extrusion nozzles distributed along a lengthwise direction and a widthwise direction of the extrusion die. In / Al / , the extrusion die, starting from the thermoplastic polymer, generates a curtain RD of continuous molten fibers, falling by gravity. The curtain of continuous molten RD fibers then passes between two counter-rotating calendering elements RC1, RC2, for example in the form of rollers, generating a 3D entanglement of fibers with an irregular or random distribution, with loop fusion between the continuous fibers and a layer of total thickness determined by the center distance between said two calendering elements RC1, RC2.

[0058] In / A2 / , the two calendering elements RC1, RC2 are driven in rotation at a speed typically lower than the falling speed of the fibers, ensuring an accumulation of fibers which leads to the formation of loops which heat-weld between fibers, generating the irregular, random, three-dimensional entanglement.

[0059] Finally, the 3D fiber entanglement is solidified by immersion in a coolant (LR) to form a padding, which, after a possible cutting operation, allows for the 3D entanglement of continuous fibers. Solidification is achieved immediately after step / B2 / , with the two guide elements being immersed halfway in the coolant for this purpose.

[0060] The continuously moving 3D fiber tangle layer is then guided out of the coolant reservoir to be dried, typically by shaking / vibrating. The moving layer is then cut by cross-sections, allowing the production of different CH first layers of padding, as seen in [Fig. 9].

[0061] The 3D fiber interlocking layer can be shaped in particular by thermoforming to form the groove Ra, or even to conform the padding to form a central part PC, intended to receive the seat occupant, and lateral parts PL, raised relative to the central part, intended to ensure lateral support of the occupant.

[0062] The present disclosure further relates to a MAT seat padding that can be obtained according to the process of the present disclosure, comprising a 3D entanglement of irregularly arranged continuous thermoplastic fibers, forming loops welded together between the fibers, and in which: - the fibers are hollow and / or solid fibers, in particular with a diameter between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm, - the fibers comprise a thermoplastic polymer, the padding comprising one or more localized areas densified and stiffened by hot pressing of the 3D interlocking and in which the 3D interlocking of the padding has an apparent density between 20 kg / m3 and 70 kg / m3, in particular between 45 kg / m3 and 65 kg / m3 outside the densified and rigidified local ZL zone(s).

[0063] According to this disclosure, the padding includes at least one densified and stiffened area comprising at least one annular bead BA which is adjoining to the fibers of the 3D entanglement on an outer periphery of the annular bead BA, said at least one annular bead defining an internal OF fixing opening said annular bead BA. A groove RA may be provided in depth of a surface of the padding intended to receive the seat occupant, said at least one annular bead B being formed on the bottom of the groove RA.

[0064] This disclosure further relates to a padding assembly 1 comprising a seat cushion according to this disclosure and a cover attached to the cushion by at least one fastening element FX, for example elastic, fixed in said at least one fastening opening OF of the annular bolster BA, in particular by elastic interlocking. The cover covers the cushion on the side of the seat occupant, and preferably under tension on the cushion.

[0065] The FX fastening member may have a cross-section, in the rest position, greater than the cross-section of the fastening orifice, and is configured to deform by decreasing in cross-section to pass through the OF fastening orifice, before regaining shape, under an elasticity of said fastening member to hook onto the BA annular rim and ensure retention of the cap, typically in tension on the padding.

[0066] Generally, particularly when the fastening member FX is configured to cooperate by interlocking in the fastening orifice OF. The shape of the fastening member FX is adapted (preferably complementary) to the shape of said annular bead BA and to the cross-section of its fastening orifice OF.

[0067] According to an embodiment illustrated in particular in [Fig.5], in particular when said fixing orifice is of circular cross-section, said fixing member FX may comprise a rod TG extended by a fork having two elastic branches Br, ending in a truncated cone TC.

[0068] Said truncated cone is split by a slot FT separating the two elastic branches Br of the fork. The slot FT separates the truncated cone into two truncated cone halves.

[0069] The split cone having a small base, at one terminal end of said fastening member, smaller than a section of said fastening orifice OF, and a large base adjoining the two arms of the fork, the large base being larger than said section of said fastening orifice OF, in a position of rest of said fixing member. The large base smaller in dimension than the section of said fixing orifice, in a constrained position of said fixing member for which the two halves of the truncated cone TC are brought close to each other.

[0070] Said fastening member FX is configured to be fitted into said fastening orifice OF of the annular bead BA by insertion of the split truncated cone TC, during which the frustoconical wall of the split truncated cone in contact with the bead BA constrains said fastening member FX into the constrained position in which the two halves of the truncated cone are brought together, allowing passage of the large base through said fastening orifice. After passage of the large base, the elastic return of said fastening member to the rest position ensures that said fastening member is locked against the annular bead BA by the bearing of the large base against the bead, in the rest position of said fastening member. This locking opposes the traction of the cap CF on the stem.

[0071] The fixing member can typically be obtained by injection molding techniques, in order to obtain, during molding, in particular the TG rod, the Be hips and the TC cone truncate.

[0072] The embodiment of [Fig. 5], with a truncated cone, is adapted to a circular shape of the annular bead and to a circular shape of the mounting hole OF. The truncated cone can thus be replaced by a truncated pyramid in the case of an annular bead of rectangular or square shape, with a mounting hole of the same shape.

[0073] The fastening element can be attached to an RB ribbon, particularly at a proximal end of the fastening element, opposite the distal end that attaches to the rim. Several FX fastening elements can be attached to the same RB ribbon, as illustrated in [Fig. 2]. The attachment between the FX fastening element and the RB ribbon can be achieved by overmolding the RB ribbon, or by any other technique (stapling, etc.). The ribbon can be attached to the cap by stitching, as shown in [Fig. 1].

[0074] The material of the MAT safety mattress and the material of said FX fastening element may be the same material, or two different materials, but having similar physicochemical properties, in particular the same chemical composition. Advantageously, this allows the mattress and the fastening element to be recycled simultaneously without separating them.

[0075] For example, the padding material MAT and the material of said fastening member FX may be a thermoplastic polymer, in particular a thermoplastic polymer whose main chain repeating motif includes the ester function and optionally the ether function, most particularly an elastomer thermoplastic whose main chain repeating pattern includes the ester function and possibly the ether function.

[0076] Also, the present disclosure further relates to a recycling process for a set of Sure mattresses according to the present disclosure, wherein the Sure mattress material MAT and said OF fastening member is a thermoplastic polymer whose main chain repeating motif includes the ester function and optionally the ether function, comprising: - optionally, separation of the CF cap from the padding assembly (1), - grinding of the padding MAT and said FX fastening element attached to the padding, for the production of granules - the use of the granules for the manufacture of a plastic product based on a thermoplastic polymer whose main chain repeating pattern includes the ester function and possibly the ether function, in particular by molding or extrusion.

[0077] Optionally, when the cap is also made of a thermoplastic, in a material compatible with that of the padding and the fastening device, the cap is not removed and is ground simultaneously with the padding and the fastening device, further simplifying recycling. List of reference signs

[0078] - 1: Padding assembly - MAT. Matelassure, - ZL. Locally densified zone, - BA. Annular bulge, - OF. Fixing opening, - OT1, OT2. Respectively first and second tooling elements, - GA. Annular throat, - RA. Groove - FX. Fixing element, - FE. Extrusion die, - RD. Fused fiber curtain, - LF. Coolant

Claims

Demands

1. A method for manufacturing seat padding comprising: - / A / Supplying padding (MAT) comprising a 3D entanglement of continuous thermoplastic fibers arranged irregularly forming loops welded together, - / B / Pressing the 3D entanglement of fibers into one or more local zones of the 3D entanglement so as to obtain one or more local zones (ZL) of the padding, densified and stiffened, the local zone(s) being configured to serve as a fixing zone,resulting in compression by a partial reduction of the thickness of the 3D entanglement in the local area characterized in that in / B / the pressing is an operation during which a first tooling element (OT1) and a second tooling element (OT2) come from either side of the 3D entanglement of thermoplastic fibers to compress and weld the fibers of the 3D entanglement of the local area and transform the thermoplastic fibers into an annular bead (BA), said annular bead (BA) in the thermoplastic material of the fibers which are entirely compressed and welded together, said annular bead having a closed trajectory, in particular circular, ovoid, polygonal, in particular rectangular, the first tooling element (OT1) and the second tooling element (OT2), when applied under pressure on the padding,include: - opposing surfaces forming, by complementary shape, an annular groove (GA) ensuring molding of the annular bead (BA), - a peripheral opening (OP), extending around an axis of the annular groove, ensuring that the annular bead (BA) remains attached to the fibers of the entanglement on an outer periphery of the annular bead (BA), and preferably over its entire periphery, the annular bead (BA) being attached to the fibers of the entanglement on an outer periphery of the annular bead (BA), and in which the annular bead (BA) defines an internal fixing orifice (OF).

2. A method according to claim 1, wherein the first tooling element (OT1) and the second tooling element (OT2), include respectively an ultrasonic sonotrode and a support and wherein in / B / the sonotrode and the support come on either side of said entanglement, the sonotrode being vibrated at a frequency typically between 20 kHz and 70 kHz to obtain the welding of the thermoplastic fibers together and form said annular bead (BA), and wherein in particular the sonotrode includes a shaped end forming an annular groove (GA) forming, by complementarity of form with the support, in / B / , said annular bead (BA).

3. Method according to claim 1 or 2, in which between / B / and / A / an intermediate step of thermoforming the 3D fiber entanglement of the padding generating a groove (RA) deep into a surface of the padding intended to receive the seat occupant, and in which at / B / the first tooling element (OT1) and the second tooling element (OT2) compress and weld the thermoplastic fibers between a bottom of the groove (RA) and a surface opposite to the surface intended to receive the seat occupant, and such that the annular bead (BA) is formed on a bottom of the groove (RA).

4. A method for manufacturing a mattress according to any one of claims 1 to 3 in which the supply step / A / comprises: - / A1 / Extrusion of a thermoplastic polymer in an extrusion die (FE) comprising extrusion nozzles distributed along a lengthwise direction and along a widthwise direction of the extrusion die, generating a curtain of continuous molten fibers (RD), falling by gravity, - / A2 / Reception of the curtain of continuous molten fibers falling by gravity from the calendering members (RC1, RC2) with a generation of a 3D fiber entanglement according to an irregular distribution with loop fusion between the continuous fibers - / A3 / optionally solidification of the 3D fiber entanglement by immersion in a coolant (LF).

5. Seat padding obtainable according to the process of claims 1 to 4 comprising a 3D entanglement of irregularly arranged continuous thermoplastic fibers, forming loops welded together between the fibers, and wherein: - the fibers are hollow and / or solid fibers, in particular with a diameter between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm, - the fibers comprise a thermoplastic polymer, the padding comprising one or more local densified and stiffened zones by hot pressing of the 3D entanglement and wherein the 3D entanglement of the padding has an apparent density between 20 kg / m³ and 70 kg / m³, in particular between 45 kg / m³ and 65 kg / m³ outside the densified and stiffened local zone(s) (ZL), and wherein the padding comprises at least one densified and stiffened zone comprising at least one annular bead (BA) adjoining the fibers of the 3D entanglement on an outer periphery of the annular bead (BA), said at least one annular bead defining an internal fastening opening (OF) annular ridge (BA)...

6. Seat padding according to claim 5, which can be obtained according to the process of claim 3, wherein said 3D entanglement of fibers having a groove (RA) deep in a surface of the padding intended to receive the seat occupant, and wherein said at least one annular bead (B) is formed on the bottom of the groove (RA).

7. Padding assembly (1) comprising a seat padding according to claim 5 or 6 and a cover fixed to the padding by at least one fastening member (FX), in particular elastic, fixed in said at least fastening opening (OF) of the annular rim (BA), in particular by elastic interlocking, the shape of the fastening member (FX) adapted, preferably complementary, to a section of the fastening opening (OF).

8. A padding assembly according to claim 7, wherein said fastening member (FX) comprises a rod (TG) extended by a fork having two elastic arms (Br) terminating in a truncated cone (TC), said truncated cone split by a slot (FT) separating the two elastic arms (Br), the slot dividing the truncated cone into two truncated cone halves, the split truncated cone having a small base at one terminal end of said fastening member, smaller than a section of said orifice of fastening (OF), and a large base adjoining the two arms of the fork, the large base being larger than said section of said fastening orifice (OF), in a rest position of said fastening member, and the large base being smaller than the section of said fastening orifice, in a constrained position of said fastening member in which the two halves of the truncated cone (TC) are elastically brought together, and in which said fastening member (FX) is configured to be fitted into said fastening orifice (OF) of the annular bead (BA), by insertion of the split truncated cone (TC), during which the frustoconical wall of the split truncated cone in contact with the bead (BA) constrains said fastening member (FX) in the constrained position in which the two halves of the truncated cone are brought together, allowing passage of the large base through said fastening orifice,then an elastic return of said fixing member to the rest position ensuring a locking of said fixing member against the annular rim (BA) by the support of the large base against the rim, in the rest position of said fixing member.

9. Padding assembly according to claim 8 or 9 wherein the padding material (MAT) and the material of said elastic element are in a thermoplastic polymer whose main chain repeating pattern includes the ester function and optionally the ether function.

10. A method for recycling a padding assembly according to claim 9, wherein the padding material (MAT) and said fastening member (OF) is a thermoplastic polymer whose main chain repetition pattern includes the ester function and optionally the ether function, comprising: - optionally, a separation of the cap (CF) from the padding assembly (1), - a grinding of the padding (MAT) and said fastening member (FX) attached to the padding, for the production of granules - a use of the granules for the manufacture of a plastic product based on a thermoplastic polymer whose main chain repetition pattern includes the ester function and optionally the ether function, in particular by molding or extrusion.

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