WO2024068471A1

WO2024068471A1 - Method for manufacturing a seat lining element comprising a padding, a cover covering the padding and a welded interface sheet

Info

Publication number: WO2024068471A1
Application number: PCT/EP2023/076246
Authority: WO
Inventors: Anne-Sophie CABOUILLET; Mathieu Cluet
Original assignee: Faurecia Sièges d'Automobile
Priority date: 2022-09-30
Filing date: 2023-09-22
Publication date: 2024-04-04
Also published as: FR3140299A1

Abstract

The present disclosure relates to a method for manufacturing a seat lining element (EG) comprising: /G1/ providing a padding (3) comprising a 3D entanglement of irregularly arranged continuous thermoplastic fibres (5) forming loops that are welded together, /G2/ providing a cover (CF), /G3/ providing an interface sheet (IT), /G4/ forming an assembly (ASS) comprising three consecutive layers on top of one another comprising the padding (3), the cover (CF) and the interface sheet (IT) inserted between the cover (CF) and the padding (3), and /G5/ welding the three layers of the assembly at least by compressing the assembly between a first press portion (PR1) and a second press portion (PR2) in a tool (OTS).

Description

Title: Process for manufacturing a seat upholstery element comprising a padding, a cap covering the padding and a welded interface sheet.

[0001] The present disclosure relates to a method of manufacturing a trim element comprising, in superposition, a cap, an interface sheet and a padding comprising a 3D entanglement of continuous fibers, and in which the cap is secured to the continuous fibers of the 3D tangle via the interface sheet welded together with the cap and the continuous fibers of the padding.

[0002] The present disclosure also relates to a seat trim element as such, as well as a vehicle seat comprising a metal structure and such a trim element.

Technical area

[0003] The present disclosure relates to the field of automobile vehicle seats which comprise a metal structure, typically with a seat frame and a backrest frame. The structure is classically obtained by stamping techniques. The seats still have padding, including a layer of seat padding and a layer of back padding which provide softness to the seat and back, and contribute to comfort in the seat.

Prior art

[0004] The seat and back paddings are generally made of urethane polymer foam, and shaped in molds. Polyurethane foam padding is satisfactory, but can retain moisture in humid conditions.

Summary [0005] This disclosure improves the situation.

[0006] According to a first aspect, the present disclosure relates to a method of manufacturing a seat trim element comprising:

/G1/ supply of a padding comprising a 3D tangle of continuous thermoplastic fibers arranged irregularly forming loops welded together,

/G2/ supply of a headdress,

/G3/ supply of an interface sheet,

/G4/ formation of an assembly comprising in superposition three successive layers comprising the padding, the cover and said interface sheet interposed between the cover and the padding,

/G5/ joining by welding of the three layers of the assembly at least by compression of the assembly between a first press part and a second press part in a tool.

[0007] According to optional characteristics of the present disclosure, taken alone or in combination;

[0008] According to one embodiment, the tooling is high-frequency welding tooling, comprising the first press part and the second press part between which the assembly is compressed, and in which in /G5/ one is joined by high frequency welding, the three layers of the assembly by subjecting the assembly thus compressed to a high frequency magnetic field of between 20 kHz and 70 kHz, the first press part and the second press part respectively forming two electrodes between which is created the high frequency magnetic field and in which the interface sheet is in a thermoplastic material configured to be thermally deformed by the high frequencies of the magnetic field in order to ensure the welding of the interface sheet to the cap and to the entanglement 3D fibers of the quilting;

[0009] According to one embodiment, the first press part being configured to come to bear against the cap via a support wall, and the second press part being configured to come to bear against the padding, and in which the support wall of the first press part can have an embossing configured to ensure superficial relief of the face of the assembly covered by the cap, in /G5/ when said assembly jointly undergoes:

- said compression between the first press part and the second press part,

- the high frequency magnetic field causing the softening of the thermoformable interface sheet;

[0010] According to one embodiment, the interface sheet the sheet can be in a material chosen from or including polyvinyl chloride derivatives, polyurethane, polyamides or even polyester derivatives;

[0011] According to one embodiment, the interface sheet can be thicker than the thickness of the cap and thicker than the thickness of the padding, in particular less than 2mm;

[0012] According to one embodiment, the 3D tangle of continuous fibers of the padding comprises in whole or in part:

-the fibers are hollow fibers and/or solid fibers, with a diameter of between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm, and/or

- the fibers comprise a thermoplastic polymer, the composition of the fibers comprising at least 95% by weight of PET, and/or in which the 3D entanglement of the padding (5) has an apparent density of between 30 kg/m3 and 70 kg/m3, more particularly between 45 kg/m3 and 65 kg/m3.

[0013] According to one embodiment, in /G1/, the supply of the padding comprising the 3D tangle of thermoplastic fibers comprises:

- /A/ Extrusion of a thermoplastic polymer in an extrusion die comprising extrusion nozzles distributed in a lengthwise direction and in a widthwise direction of the extrusion die, generating a curtain of melted, falling continuous fibers by gravity,

- /B/ Reception of the curtain of melted continuous fibers falling by gravity against a shaping means, with generation of a 3D tangle of fibers according to an irregular distribution with fusion of loops between the continuous fibers,

- HERE Solidification of the 3D tangle of fibers by immersion in a cooling fluid.

[0014] According to one embodiment, the cap covers a front face of the padding, and in the front face of the padding provided in /G1/ is in relief comprising lateral flanges projecting relative to a central part, on the other hand and on the other hand, from the central part, the lateral flanges configured to ensure lateral support of the occupant of the trim element.

[0015] According to a second aspect, the present disclosure relates to a seat upholstery element capable of being obtained by the manufacturing method according to the present disclosure comprising superimposed, a cover, an interface sheet and a padding comprising a 3D tangle of continuous fibers, and in which:

- the continuous fibers are hollow fibers and/or solid fibers, with a diameter of between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm,

- the continuous fibers comprise a thermoplastic polymer, the composition of the fibers comprising at least 95% by weight of PET, and in which the 3D entanglement of the padding (5) has an apparent density of between 30 kg/m3 and 70 kg /m3, and more particularly between 45 kg/m3 and 65 kg/m3, and in which the cap is secured to the continuous fibers of the 3D entanglement via the interface sheet (welded jointly to the cap and to the continuous fibers of the padding.

[0016] According to a third aspect, the present disclosure relates to a vehicle seat comprising:

- a metal structure comprising in particular a seat frame and a backrest frame,

- a seat upholstery element according to the present disclosure coupled to the metal structure, in particular a seat upholstery element coupled to the seat frame and/or a backrest upholstery element coupled to the backrest frame.

Brief description of the drawings

[0017] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the appended drawings, in which:

Fig. 1

[0018] [Fig. 1] is a view of a motor vehicle seat, according to the present disclosure, illustrating the metal structure of the seat supporting a plastic backrest interface intended to receive a layer of backrest padding and a plastic seat interface intended to receive a layer of seat padding, the backrest and seat padding being not illustrated.

Fig. 2

[0019] [Fig. 2] is a sectional view of the seat of Figure 1, to which a back padding is added, and a seat padding, according to the present disclosure comprising an irregular entanglement, in three 3D dimensions of continuous thermoplastic fibers comprising loops between fibers heat-welded to each other.

Fig. 3

[0020] [Fig. 3] is a schematic view of the manufacturing process allowing the manufacture of the 3D entanglement comprising an extrusion of a thermoplastic polymer in an extrusion die generating a curtain of melted continuous fibers, falling by gravity, receiving the curtain of fibers continuous melted between two counter-rotating calendering members, with generation of a 3D tangle of fibers and solidification of the 3D tangle of fibers by immersion in a cooling liquid, then obtaining padding by transverse cuts in the sense of scrolling. [0021] [Fig. 4] illustrates different extrusion dies which can be implemented according to the method of the present disclosure, namely an extrusion die comprising extrusion nozzles for the extrusion of solid fibers to obtain padding from solid fibers according to a first possibility, an extrusion die comprising extrusion nozzles for the extrusion of hollow fibers to obtain padding from solid fibers according to a second possibility, and a die 'extrusion, mixed, comprising extrusion nozzles for the extrusion of hollow fibers and extrusion nozzles for the extrusion of solid fibers according to a third possibility, allowing the obtaining of a padding comprising depending on the thickness, a lower, structural underlay, formed from a tangle of hollow fibers, a soft upper underlay, formed from a tangle of solid fibers, and an underlay, intermediate between the lower underlay and the underlay upper, connecting.

Fig. 5

[0022] [Fig. 5] is a view of a production line comprising successively:

- equipment configured for implementing the process according to Figure 3, comprising an extrusion of a thermoplastic polymer in an extrusion die generating a curtain of melted continuous fibers, falling by gravity, receiving the curtain of melted continuous fibers between two counter-rotating calendering members, with generation of a 3D entanglement of fibers and solidification of the 3D entanglement of fibers by immersion in a cooling liquid,

- a station configured for the implementation of transverse cuts, to obtain separate and distinct padding, according to a layer of constant thickness

- a carousel, comprising on a chassis, rotating around a vertical axis, a plurality of thermoforming tools, each comprising a lower mold part and an upper mold part, the thermoforming tool configured to follow a sequence, from an opening position of the tooling, the sequence synchronized with the rotation of the carousel, discontinuous, comprising a first unloading/loading position of a padding, a second closing position of the tooling with compression and heating in order to obtain thermoforming of the padding, a third cooling position, and a fourth opening position of the tooling,

- a packaging station for the padding shaped by thermoforming.

Fig. 6

[0023] [Fig. 6] shows is a view of equipment configured for implementing the method according to the present disclosure, comprising:

- an extrusion die comprising nozzles distributed in a lengthwise direction and in a width (transverse) direction of the extrusion die, generating a curtain of melted continuous fibers, falling by gravity,

- a molding tool comprising a molding cavity, open towards the extrusion die, directly above the die, configured to receive the curtain of melted continuous fibers falling by gravity into the molding cavity of the molding tool molding so as to generate a 3D tangle of fibers in an irregular distribution with fusion of loops between the continuous fibers,

- guides allowing the molding tool to be lowered into a tank containing a cooling liquid ensuring the solidification of the entanglement,

- a logic processing unit comprising a control module having a microprocessor and a memory configured for controlling the extrusion nozzles, and controlling the descent of the molding tool into the cooling liquid, in a motorized manner .

Fig. 7a

[0024] [Fig. 7a] illustrates a first phase of the process for which the logic unit controls the nozzles so as to fill only the hollow reliefs of the molding cavity, on either side of a central portion of the molding cavity, the nozzles of the extrusion die located to the right of the projecting relief on the central portion of the molding cavity being kept closed by the logic unit.

Fig. 7b [0025] [Fig. 7b] shows a second phase, consecutive to the first phase, for which the logic unit opens all of the extrusion nozzles so that the curtain of molten fibers fills the entire surface of the molding cavity in the direction longitudinal and in the transverse direction of the molding cavity.

Fig. 7c

[0026] [Fig. 7c] shows a third phase, consecutive to the second phase, for which the logic unit only opens nozzles so that the curtain of molten fibers fills the central portion of the molding tool located between the two hollow reliefs, in seen to form on the dorsal face of the padding, a central portion projecting relative to two lateral portions of the dorsal face.

Fig. 7d

[0027] [Fig. 7d] shows on the left an instant of third phase consecutive to FIG. 7c, and on the right, after demolding, a padding formed from a 3D tangle of fibers in an irregular distribution with fusion of loops between the continuous fibers, the padding having a front face shaped by the molding cavity of the molding tool, and a back face not shaped by the molding tool.

Fig. 8

[0028] [Fig. 8] is a view of high frequency welding tools comprising a first press part, forming a positive electrode and a second press part between which the assembly of the three layers including the cap, the interface sheet is compressed and the padding, to ensure the attachment of the cover to the padding, by welding the interface sheet jointly to the cover and to the continuous fibers of the 3D tangle of the padding.

Fig. 9 [0029] [Fig. 9] is a view on the left of the elements of the assembly, namely the cover, the padding and the interface sheet in the unassembled state, and on the right of the assembly of the elements via the sheet thermoformable interface, thermally deformed by the high frequencies of the tooling in Figure 8.

Fig. 9a

[0030] [Fig. 9a] is a detail and sectional view of the trim element of Figure 9.

Fig. 10

[0031] [Fig. 10] is a schematic of the diagram illustrating the steps of the manufacturing process of the packing element.

Fig. 11

[0032] [Fig. 11 ] is a seat structure, comprising a backrest frame and a seat frame, and to which a trim element according to the present disclosure can be coupled, in particular a backrest trim and a seat trim.

Description of embodiments

[0033] The drawings and the description below contain, for the most part, elements of a certain nature. They can therefore not only be used to better understand this disclosure, but also contribute to its definition, if necessary.

Also, the present disclosure relates to a seat 1 comprising:

- a metal structure 2,

- a trim element comprising a padding 3 covered by a CF cap.

[0035] In Figures 1 and 2, the seat 1 comprises an interface 4 located between the structure 2 and the padding 3 (cover not shown). Alternatively, the seat 1 does not have the interface 4, and the padding is directly attached to the structure metal 2, and for example on a seat structure 2 as illustrated in Figure 11.

[0036] In Figure 2, a mark XYZ is illustrated, the direction and the Z direction according to the vertical.

The structure 2 comprises a seat frame 20 and a backrest frame 21, articulated around a transverse axis of rotation, typically by means of joints, preferably of the continuous type.

[0038] The seat frame 20 includes:

- two side flanges, extending from a rear edge of the seat and to a front edge, in the direction X, or slightly inclined relative to the longitudinal direction of a transverse axis and,

- a front piece, connecting two front ends of the flanges, and extending in the transverse direction. The front part and the flanges can advantageously be shaped sheets, for example, by stamping techniques as illustrated in Figures 1 and 2. In Figure 11, the seat structure, the flanges of the seat frame are braced by a front tube, and a rear tube, extending transversely, in the Y direction.

The backrest frame comprises side uprights, extending in height, as well as an upper crossbar connecting two upper ends of the uprights. The uprights and the upper crosspiece are advantageously shaped sheets, for example by stamping techniques.

The padding 3 comprises a seat padding layer 3a which provides comfort to the seat and which can be received on a seat interface 4a inserted between the seat frame 20 according to the embodiment of the figure 2. The padding 3 also includes a backrest padding layer 3b which provides comfort to the backrest and which is received on a backrest interface 4b, interposed between the backrest frame 21 and the backrest padding layer 3b. The padding 3, in particular the seat padding layer 3a and/or the backrest padding layer 3b, comprises a three-dimensional (“3D”) tangle 30 of continuous, thermoplastic fibers 5 arranged irregularly, forming loops welded together between the fibers 5.

The fibers can be hollow fibers 5a and/or solid fibers 5b. The fibers can have a diameter of between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm. By "continuous" in "continuous fibers" is meant the fact that the fibers are of length much greater than the diameter of the fibers, and due to the processes described below, typically at least by a ratio 100, or even 500, or even 1000. , and in particular due to the manufacturing process described below. Very often, and therefore the fibers 5 extend continuously from one edge to the other of the padding.

The fibers 5 comprise a thermoplastic polymer, the composition of the fibers preferably comprising at least 95% by weight of PET. For example, the composition of the fibers, or even the padding, includes:

- 95% to 99% by weight of a first polymer from the polyester family such as PET (polyethylene terephthalate),

- 1% to 5% by weight of a second polymer from the polyester family such as PTT (Polytrimethylene terephthalate) or PBT (Polybutylene terephthalate). The sum of PET and PTT (or PBT) can make 100% by weight of the fibers, or even the padding.

Preferably, the voids between the fibers 5 of the 3D tangle of fibers 5 of the padding 3 are left free. A structural and breathable padding is obtained, due to the numerous inter-spaces between the fibers which promote air circulation.

[0045] In Figure 2, the seat padding layer 3a extends in length along a longitudinal direction Xa from the seat from a rear edge to a front edge of the seat, and in width following a transverse direction a from the seat of a first lateral edge to a second lateral edge, as well as in thickness along an orthogonal direction Za, which is orthogonal to the longitudinal direction and to the transverse direction of the seat. The thickness of the seat padding layer can be between 60mm to 100mm.

[0046] In Figure 2, the backrest padding layer 3b extends in length along a longitudinal direction Xb of the backrest from a lower edge towards an upper edge of the backrest, and in width along a transverse direction Yb of the backrest d 'a first side edge up to a second side edge, as well as in thickness along an orthogonal direction Zb which is orthogonal to the longitudinal direction and the transverse direction of the backrest. The thickness of the back padding layer can be between 30 mm and 60 mm.

[0047] The interface 4, in particular the seat interface 4a or the backrest interface 4b, may comprise a material entirely or partially made of plastic. For example, said interface 4 is made of ABS (acrylonitrile butadiene styrene) and/or PC (Polycarbonate) and/or P/E (Polypropylene/Polethylene copolymer).

[0048] Generally speaking, the interface 4, in particular the seat interface 4a or the backrest interface 4b, may include a shell. The shell can be a molded part or a thermoformed part.

[0049] In particular, said folder interface 4b may include:

- at least one deformable backrest shell 40, receiving the padding which is a backrest padding 3b, said deformable shell 40 being configured to take different shapes in particular from an initial position of lumbar lordosis and in particular up to a final position of kyphosis lumbar, in response to a variable load applied by the back of the seat occupant,

- a system coupling said deformable backrest shell 40 to the structure comprising upper movement control links 41 s, and lower movement control links 41 i.

The upper movement control links 41 s and/or the lower movement control links 41 i are typically articulated links which may include connecting rods.

[0051] Note that the apparent density of the 3D tangle of continuous fibers 5 is between 30 kg/m ³ and 70 kg/m ³ , for example between 45 kg/ ^m3 and 65 kg/ ^m3 . The 3D entanglement piece 30 is uniform, so that the density of the figures is constant or varies little (variation less than 5%) in the padding 3a.

[0052] We now describe two manufacturing processes making it possible to obtain the 3D entanglement 30 of continuous fibers.

[0053] A first manufacturing process, as illustrated schematically in Figure 3, comprises:

- /A/ Extrusion of a thermoplastic polymer in an extrusion die 6 comprising extrusion nozzles 60 distributed in a length direction X6 and in a width direction Y6 of the extrusion die, generating a curtain of fibers continuous melts 50, falling by gravity;

- /B/ Reception of the curtain of melted continuous fibers falling by gravity against a shaping means, with generation of a 3D tangle of fibers 5 according to a random distribution with fusion of the loops between the continuous fibers, in particular according to a thickness layer determined by the shaping means. Thus, the fibers are arranged irregularly, as already described. According to this method, the shaping means comprises two counter-rotating calendering members 7, 8. The ETR center distance between the two counter-rotating members 7, 8 delimits the thickness of the interlocking part;

- HERE Solidification of the 3D tangle of fibers by immersion in a fluid, for example LF coolant, such as water.

The extrusion nozzles 60 are preferably distributed regularly along the length direction X6 of the extrusion die, as well as in width along the width direction Y6.

[0055] The thickness of the cushioning layer formed by the entanglement can be adjusted by adjusting the center distance between the two guide members 7.8.

[0056] In /B/, the two calendering members 7, 8 are rotated at a speed, typically lower than the speed of fall of the fibers, ensuring an accumulation of fibers at the origin of the random formation of loops which heat seal between fibers, generating the irregular entanglement in three dimensions. Solidification in /C/ is obtained just after step /B/, the two guide members can be immersed halfway up, for this purpose.

[0057] The temperature of the extrusion carried out in /A/ in the extrusion die is typically between 180°C and 240°C. The extrusion die is supplied with polymer granules

[0058] The layer of 3D entanglement of fibers, in continuous motion, is then guided outside the coolant reservoir to be dried, typically by shaking/vibrations. The scrolling layer is then cut, by transverse cuts, allowing different paddings to be obtained including 3D entanglement. These paddings extend in length, for example in length along the longitudinal direction Xa of the seat padding layer (or in length along the longitudinal direction of the layer.

According to one embodiment, the apparent density can be homogeneous depending on the length and width of the layer, and as illustrated in Figure 5, top. The density of the number of extrusion nozzles is thus homogeneous following the length direction of the extrusion die.

[0060] According to another embodiment not illustrated, the extrusion die 6 may comprise, along the length direction X6 of the extrusion die, several distinct zones comprising distinct surface densities of number of nozzles, comprising at least one first zone with low surface density of number of nozzles, and at least a second zone with high surface density of number of nozzles.

[0061] Such a method makes it possible to obtain at least a first zone having a low apparent density and at least a second zone having a high apparent density, following the direction of the 3D entanglement of fibers extending along the direction longitudinal X6 of the extrusion die.

[0062] Thus, and possibly:

- the cushioning layer of the seat 3a obtained can thus include different zones presenting different apparent densities, following the longitudinal direction Xa of the layer of the cushioning of the seat 3a and/or,

- the back padding layer 3b obtained can thus comprise different zones having different apparent densities, distributed along the longitudinal direction Xb of the back padding layer 3b.

[0063] According to one embodiment, the extrusion die may comprise extrusion nozzles configured for the extrusion of solid fibers only, and as illustrated at the top right in Figure 4, allowing the production of padding full fiber.

[0064] According to another embodiment, the extrusion die may comprise extrusion nozzles configured for the extrusion of hollow fibers only, and as illustrated at the bottom right in Figure 4, allowing the obtaining of hollow fiber padding.

[0065] According to another illustrated embodiment, the extrusion die 6 can include not only extrusion nozzles for the extrusion of solid fibers but also extrusion nozzles for the extrusion of hollow fibers.

[0066] Thus, and as illustrated in Figure 4 in the middle view, the extrusion die 6 can comprise, according to the width dimension Y6 of the extrusion die, a first section 60a provided with first nozzles d extrusion for the generation of hollow fibers 5a which extend in length along the length of the die 6, and a second section 60b provided with second extrusion nozzles for the generation of solid fibers 5b which extend in length over the length of the die 6.

[0067] As illustrated in the right view in Figure 4, the seat padding layer 3a and/or the backrest padding layer 3b may comprise, depending on the thickness:

- a lower, structural underlayer, formed from a tangle of hollow fibers 5a of thickness Epinf,

- an upper, soft underlayer, formed from a tangle of full Epsup fibers,

- an underlay, intermediate between the lower underlay and the underlay upper, connection comprising a tangle of solid fibers and hollow fibers welded to each other, of Epint thickness.

[0068] The apparent density of the lower sub-layer and the apparent density of the upper strain-layer may be identical or close to + or - 5% depending on the thickness of the layer, at least locally in the longitudinal direction. and the transverse dimension of the layer.

[0069] Generally speaking and in Figure 4, the thickness Epsup of the upper sub-layer formed by the solid fibers 5b is less than the thickness Epinf of the structural sub-layer, formed by the hollow fibers 5a.

[0070] Note that this first embodiment applies in particular to the entanglement part 30 of Figure 3.

[0071] The 3D tangle of continuous fibers, obtained following the process of Figure 3, is of constant thickness due to the fact that the calendering members 7.8 are members with a cylindrical calendering surface.

[0072] The padding 3 can be raised by thermoforming, in a thermoforming tool comprising an upper mold part and a lower mold part in which the 3D tangle of continuous fibers is compressed, the heated mold parts.

[0073] The mattress manufacturing process can be implemented on a view of a production line comprising successively, depending on the direction of processing:

- equipment configured for implementing the process according to Figure 3, comprising an extrusion of a thermoplastic polymer in an extrusion die 2 generating a curtain R of melted continuous fibers, falling by gravity, receiving the curtain of fibers continuous melts between two counter-rotating calendering members, with generation of a 3D entanglement of fibers and solidification of the 3D entanglement of fibers by immersion in a cooling liquid,

- a cutting station configured for carrying out transverse cuts, to obtain separate and distinct padding, - a CAR carousel, comprising on a chassis, rotatable around, a plurality of thermoforming tools, each comprising a lower mold part and an upper mold part, the thermoforming tool configured to follow an operating sequence, synchronized at the discontinuous rotation of the carousel,

- an EMB packaging station for the padding shaped by thermoforming.

[0074] The offcuts of padding at the cutting station can be crushed/shredded and recycled at the entrance to the extrusion die, and as illustrated by an arrow in Figure 3.

[0075] The carousel is operated by rotating discontinuous material. The thermoforming tooling includes several positions correlated to the rotation of the carousel.

[0076] The positions are distributed angularly around the axis of rotation of the carousel and are fixed. The positions include a first position for unloading/loading a padding for which the upper and lower mold parts are spaced apart allowing the extraction of a thermoformed padding or the insertion of a non-thermoformed padding by an operator ( or a robotic system), a second closing position of the tooling with compression of the padding and heating in order to obtain thermoforming of the padding to a desired shape, typically in relief, a third cooling position, and a fourth position opening of the tool.

[0077] According to a variant of the embodiment, not illustrated, in particular an alternative to relief by thermoforming, the shaping of the padding and the 3D entanglement can be obtained by the choice of calendering members 7 , 8 advantageously presenting a calendering wall which is then non-cylindrical, and unlike the example illustrated in Figure 3, and so as to calender a front face of the non-flat padding, for example having a central portion PC and lateral flanges Bl . [0078] According to a second embodiment of the method of manufacturing the padding, the shaping means comprises molding tooling OM comprising a CAV molding cavity.

[0079] We now detail this second embodiment with reference to Figures 6 and 7a to 7d.

[0080] Equipment configured for implementing the method according to the present disclosure, illustrated in Figure 6, may include:

- an extrusion die 6 comprising nozzles 60 distributed along a length direction X and along a width direction Y (transverse) of the extrusion die, configured to generate a curtain of melted continuous fibers, falling by gravity,

- the molding tool OM comprising the molding cavity CAV, open towards the extrusion die 6, directly above the extrusion die, the tool being configured to receive the curtain R of falling melted continuous fibers by gravity in the CAV molding cavity of the OM molding tool so as to generate a 3D entanglement of fibers according to an irregular distribution with fusion of loops between the continuous fibers,

- possibly guides G allowing the molding tool to be lowered into a tank containing a cooling liquid,

- a logic processing unit U comprising a microprocessor and a memory containing control instructions. The instructions can be configured for controlling the extrusion nozzles, or even controlling the descent of the molding tool in a motorized manner, along guide G.

[0081] The length direction X and the width direction Y typically extend along a horizontal plane; the molding tool being positioned vertically above the extrusion die.

[0082] The molding cavity extends between flanks FI1, FI2, FI3, FL4, in particular two end flanks FI1 and FI3 at two longitudinal ends of the molding tool, spaced along the length direction two lateral flanks on the sides of the mold spaced in the width direction Y. [0083] The extrusion nozzles 60 are distributed along the length direction X and along the width direction Y of the extrusion die. The nozzles 60 are configured according to a matrix to generate at least temporarily a curtain of molten continuous fibers covering the entire surface of the molding cavity, extending from one side of the mold to the other, namely a curtain extending extending from one end flank FI1 to the other end flank FI2 in the length direction X and extending from one side flank FL2 to the other side flank FL4 in the width direction Y.

[0084] Advantageously, the nozzles can be advantageously controllable (individually, or at least in subgroups), configured so as to be able to change the shape of the curtain of fibers, in particular in the longitudinal direction X and/or in the transverse direction. Y. Such control of the nozzles individually or at the very least in subgroups can allow the development of 3D entanglements of complex shape, and according to an embodiment based on a mode of additive manufacturing inspired by stereolithography.

[0085] Said logic processing unit U then preferably comprises a control module comprising a microprocessor and a memory comprising instructions for, in /A/, controlling the nozzles so as to generate a curtain of fibers, of variable shape over the course of of extrusion. Such control makes it possible to generate padding, in particular of complex shape, having in particular a thickness in the vertical direction Z, which can be variable in the longitudinal direction molding.

[0086] Such operation is inspired by additive manufacturing techniques, in particular stereolithography. The padding to be manufactured can typically be designed and determined by CAD software in a given format, then can be exported in a format such as STL format.

[0087] The STL file is transmitted to the control module of the logic unit U. The control module cuts the padding into slices of typically fixed thickness in the vertical direction Z. During manufacturing the module controls the nozzles of the extrusion die to successively produce the different slices of the padding.

[0088] Figures 7A to 7D illustrate, by way of example, different views of the filling of the molding tool during extrusion with a view to obtaining a padding, of complex shape, which includes a front face FF (molded by the molding cavity) notably comprising lateral flanges Bl projecting relative to a central part PC of the front face FF.

[0089] Such a geometry of the front face makes it possible to obtain by molding a cushioning geometry guaranteeing good lateral support for the occupant.

[0090] Also notably, the padding may include a dorsal face FD (not molded by the molding cavity) comprising a central portion PCE projecting relative to the lateral portions PL.

[0091] Such a geometry of the dorsal face FD can be configured to rest against a seat structure, and in particular advantageously without having to use an intermediate plastic shell between the padding and the structure to allow its integration.

[0092] Also, the present disclosure relates to a method of manufacturing a seat MAT padding, such as a seat or backrest padding, and in which the padding comprising the 3D interlocking piece is obtained, 30, of continuous thermoplastic fibers arranged irregularly forming loops welded together by:

- /A/ Extrusion of a thermoplastic polymer in the extrusion die 6 comprising extrusion nozzles 60 distributed along a length direction X and along a width direction Y of the extrusion die, generating a curtain R of continuous melted fibers, falling by gravity,

- /B/ Receiving the curtain of melted continuous fibers falling by gravity into the CAV molding cavity of the OM molding tool so as to generate a 3D entanglement of fibers according to an irregular distribution with fusion of loops between the continuous fibers, said 3D entanglement of fibers being shaped to said molding cavity, - /C/ Solidification of the 3D tangle of fibers conforming to the molding cavity by immersion in an LF cooling liquid.

[0093] The temperature of the extrusion carried out in /A/ in the extrusion die can be between 180°C and 240°C. The extrusion die is typically supplied with thermoplastic granules.

[0094] Figures 7A and 70B disclose by way of example, a mold section along a plane YX, having a bottom with a projecting relief RS on a central portion of the section, and two hollow reliefs RC, on either side and the other of this central portion in the direction Y. Such recessed reliefs can be shaped for the molding of the side flanges Bl. These side flanges project relative to a central part PC of the padding from the front face FF .

[0095] When the bottom has hollow and projecting reliefs, preferably in /A/ said logic unit controls the nozzles so as in /B/ to fill the hollow relief(s) RC of the tooling with molding, prior to the projecting relief(s) RS of the molding tool.

[0096] Thus in Figure 7a, the extrusion begins, during a first phase, by the generation of a curtain of fibers molten in two distinct parts which only fill the two hollow reliefs RC for the molding of the tubes lateral, and not a central part of the tools between these two reliefs.

[0097] Figure 7b is a consecutive view of the extrusion which shows a second phase consecutive to the first phase for which the logic unit U opens all of the nozzles so that the curtain fills the entire section, cavity molding, namely not only the projecting relief RS on the central part, but the two hollow reliefs.

[0098] Thus, and advantageously, the bottom of the mold can comprise:

- a central portion, following a projecting relief RS, configured to conform a central part PC of a front face FF of the padding facing the occupant of the seat intended to receive the user's buttocks for the seat padding or the back of the occupant for backrest padding, and

- lateral portions, on either side, of the central portion, following two reliefs hollow RC, configured so as to form two lateral flanges BL of the padding, projecting from the central part PC, on the front face FF, the lateral flanges configured to ensure lateral support of the occupant.

[0099] According to one embodiment, in /A/, at least in a final phase of the extrusion, the logic unit U controls the nozzles 20 so as to generate in /A/ a curtain of fibers located on a portion central part of the molding tool, so as to form on a dorsal face FD of the padding, opposite the front face, a central portion PCE projecting relative to lateral portions PL of the dorsal face FD, located on the back of the two BL side flanges.

[0100] Thus, in Figures 7C and 7D, we note that the logic unit U controls the nozzles, on a third phase consecutive to the second phase, so as to generate a curtain of molten fibers which fills the projecting relief RS on the central portion of the bottom, and not the two hollow reliefs RC.

[0101] Such a geometry of the dorsal face FD, comprising a central portion PCE projecting (in the direction Z) with respect to lateral portions PL can allow integration of the padding 3 on the structure 2.

[0102] Generally speaking, in ICI it is possible to obtain the solidification of the 3D tangle of fibers by immersion in a cooling liquid with control of the movement of the molding tool relative to a free surface SL of the cooling liquid.

[0103] The free surface SL can be moved in a motorized manner in order to obtain the solidification of the 3D entanglement by immersion in the cooling liquid LF, progressively during additive manufacturing, subsequent to receipt of the curtain of melted continuous fibers falling by gravity into the molding cavity, and preferably following a duration of less than 4s between reception of the curtain of fibers generating the 3D entanglement, and immersion of the 3D entanglement.

[0104] By way of example, the motorized movement of the molding tool OM relative to the free surface SD of the cooling liquid can be obtained by plunging the OM molding tool in a motorized manner into a tank containing the cooling liquid.

[0105] Generally speaking, the processing logic unit U, in particular its control module, can control and synchronize the control of the nozzles 20 and the motorized movement of the free surface SL of the cooling liquid.

[0106] Generally speaking, the nozzles 60 may comprise nozzles 60 configured to generate hollow fibers and/or solid fibers.

[0107] The logic processing unit can also optionally control the nozzles to change over time the nature of the fibers of the curtain, namely for example solid fibers, for example on a first phase of extrusion, then hollow fibers on a second phase of extrusion.

[0108] Full fibers can preferably be used, superficially on the front face FF intended to be in contact with the occupant of the seat in order to form a first “soft” layer, and preferably hollow, “structural” fibers on the the remainder of the thickness of the padding below this first layer to form a structural underlay.

[0109] The present disclosure also relates to a method of manufacturing a seat lining element EG comprising:

/G1 / supply of a padding 3 comprising a 3D tangle of thermoplastic fibers 5, continuous irregularly arranged forming loops welded together,

ZG2Z supply of a CF cap,

ZG3Z supply of an IT interface sheet

ZG4Z formation of an ASS assembly comprising in superposition three successive layers comprising the padding 3, the CF cap and said IT interface sheet interposed between the CF cap and the padding),

ZG5Z joining by welding of the three layers of the assembly at least by compression of the assembly between a first press partPRI and a second press part PR2 in an OTS tool. [0110] Generally speaking, the padding 3 may include all or part of the following characteristics:

-the fibers are hollow fibers 5a and/or solid fibers 5b, with a diameter of between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm, and/or

- the fibers 5 comprise a thermoplastic polymer, the composition of the fibers comprising at least 95% by weight of PET, and/or in which the 3D entanglement of the padding (5) has an apparent density of between 30 kg/m ³ and 70 kg/m ³ , and in particular between 45 kg/m ³ and 65 kg/m ³ .

[0111] Generally speaking, in /G1/, the supply of the padding 3 comprising the 3D tangle of thermoplastic fibers 5 comprises:

- /A/ Extrusion of a thermoplastic polymer in an extrusion die 6 comprising extrusion nozzles 60 distributed in a length direction X6 and in a width direction Y6 of the extrusion die, generating a curtain of fibers continues melted, falling by gravity,

- /B/ Receiving the curtain of melted continuous fibers falling by gravity against a shaping means, with generation of a 3D tangle of fibers (5) in an irregular distribution with fusion of loops between the continuous fibers,

[0112] The method can be that previously described, and illustrated for information purposes in Figure 2 for which the shaping means are calendering members 7, 8. The calendering members 7,8 can be cylindrical. The padding can be raised by thermoforming the padding thus obtained. Alternatively, the padding can be raised by calendering members having a non-cylindrical calendering wall.

[0113] The method can be described and illustrated for information purposes in Figure 6 for which the shaping means is a molding tool and whose molding cavity can allow relief, in particular of the front face FF of the padding. [0114] Thus in general, the front face FF of the padding provided in /G1/, covered by the cap CF, is in relief. The front face FF can thus comprise lateral flanges Bl projecting relative to a central part PC, on either side of the central part PC, the lateral flanges Bl configured to ensure lateral support of the occupant of the filling element.

[0115] The side flanges and the central part can be raised, according to the process described, by the shape of the calendering members, or by successive thermoforming step, or by the shape of the cavity of the tooling. OM molding according to the second process described.

[0116] Generally speaking, the CF cover is an element intended to come into contact with the occupant of the seat, for example with the back of the occupant for a backrest trim element, or even with the thighs/buttock of the seat. the occupant for a seat trim element.

[0117] The cap can be made of leather, synthetic material, or even a textile, or any other material. The interface sheet IT is made of a thermoformable material which is welded jointly to the cover CF and to the continuous fibers 5 of the padding 3 to ensure the connection of the cover to the padding.

[0118] According to one embodiment, the tooling is high-frequency welding tooling, which comprises the first press part PR1 and the second press part PR2 between which the assembly is compressed.

[0119] In /G5/ the three layers of the assembly are joined together by high frequency welding by subjecting the assembly thus compressed to a high frequency magnetic field of between 20 kHz and 70 kHz, the first press part and the second part press respectively forming two electrodes between which the high frequency magnetic field is created.

[0120] The interface sheet IT is in a thermoplastic material configured to be thermally deformed by the high frequencies of the magnetic field in order to ensure the welding of the interface sheet to the cap and to the 3D entanglement of fibers 5 of the padding 3. [0121] The interface sheet, the IT sheet, is made of a thermoplastic material, which is compatible with being heated by high frequency techniques. The material can be chosen from or include derivatives of polyvinyl chloride (PVC), polyurethane (PU), polyamides (PA) or even polyester derivatives.

[0122] The interface sheet IT is thick, typically less than the thickness of the cap CF and typically less than the thickness of the padding 3, in particular less than 2 mm.

[0123] The cap CF covers a front face FF of the padding 3, which can typically be in relief comprising lateral flanges Bl projecting relative to a central part P), on either side of the central part PC , the lateral flanges Bl configured to ensure lateral support of the occupant of the trim element. Such relief of the front face of the padding is typically provided in /G1/.

[0124] The OTS welding tool can make it possible to shape the packing element at least superficially. For this purpose and in general terms, the first press part P41 can be configured to come to bear against the cap CF via a support wall, and the second press part PR2 can be configured to come to bear against the padding 3. The support wall of the first press part PR1 can then present an embossing configured to ensure superficial relief of the face of the assembly covered by the cap, in /G5/ when said assembly undergoes jointly:

- said compression between the first press part PR1 and the second press part PR2,

- the high frequency magnetic field causing the softening of the thermoformable IT interface sheet.

[0125] In Figure 10 is illustrated a diagram of the steps of the process for manufacturing the packing element which includes the following steps:

- in the opening step OP, the welding tool is opened by spacing the first press part PR1 relative to the second press part PR2, in step PS, the positioning of the cap assembly /leaf interface/padded between the two press parts PR1, PR2,

- in step CL, the first press part PR1 and the second press part PR2 close by compressing the different layers of the assembly together,

- in the HT stage, in the closed position of the tool, a high frequency magnetic field, causing the thermoplastic interface sheet to rise in temperature until the CF cap is secured to the padding 3, via the IT interface sheet,

- in step OP, the source of high frequency magnetic fields is stopped, then the first press part PR1 and the second press part PR2 are opened, to allow the extraction of the trim element EG.,

[0126] The present disclosure also relates to a seat trim element capable of being obtained by the manufacturing process according to the present disclosure.

[0127] Said filling element comprises in superposition, a cap CF, an interface sheet IT and a padding 3 comprising a 3D tangle of continuous fibers 5, and in which:

- the continuous fibers 5 are hollow fibers 5a and/or solid fibers 5b, with a diameter of between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm,

- the continuous fibers 5 comprise a thermoplastic polymer, the composition of the fibers comprising at least 95% by weight of PET, and in which the 3D entanglement of the padding (5) has an apparent density of between 30 kg/m ³ and 70 kg/ ^m3 ; in particular between 45 kg/m ³ and 65 kg/m ³ .

[0128] The CF cap is secured to the continuous fibers 5 of the 3D tangle via the IT interface sheet welded jointly to the CF cap and to the continuous fibers 5 of the padding 3.

[0129] The present disclosure also relates to a vehicle seat 1 comprising:

- a metal structure 2 comprising in particular a seat frame (20) and a backrest frame 21,

- a seat upholstery element EG according to the present disclosure, coupled to the metal structure 2, in particular a seat upholstery element coupled to the seat frame 20 and/or a backrest upholstery element coupled to the backrest frame 21.

Nomenclature

[0130] - 1: Seat,

- 2: Structure,

- 20. Seat frame,

- 3: Quilting,

- 3a: Seat cushioning layer,

- Xa, Ya, Za: Directions in length, width and thickness of the seat padding layer,

- 3b: Back padding layer,

- 30. 3D tangle of fibers,

- Xb, Yb, Zb: Directions in length, width and thickness of the back padding layer,

- 4: Interface,

- 41s, 41 i. Upper and lower movement control links,

- 5: Fibers,

- 5a. Hollow fibers,

- 5b. Full fibers,

- 6 Extrusion die,

- 60 extrusion nozzles,

- 60a. Extrusion nozzles for the extrusion of hollow fibers,

- 60b. Extrusion nozzles for the extrusion of solid fibers,

- 7, 8. Counter-rotating calendering members

-LF. Cooling liquid.

Claims

[Claim 1] Process for manufacturing a seat trim element (EG) comprising:

/G1 / supply of a padding (3) comprising a 3D tangle of thermoplastic fibers (5), continuous irregularly arranged forming loops welded together,

/G2/ supply of a cap (CF),

/G3/ supply of an interface sheet (IT),

/G4/ formation of an assembly (ASS) comprising in superposition three successive layers comprising the padding (3), the cap (CF) and said interface sheet (IT) interposed between the cap (CF) and the padding (3 ),

/G5/ joining by welding of the three layers of the assembly at least by compression of the assembly between a first press part (PR1) and a second press part (PR2) in a tool (OTS).

[Claim 2] Manufacturing method according to claim 1, in which the tooling is high frequency welding tooling, comprising the first press part (PR1) and the second press part (PR2) between which the assembly is compressed , and in which in /G5/ the three layers of the assembly are joined by high frequency welding by subjecting the assembly thus compressed to a high frequency magnetic field of between 20 kHz and 70 kHz, the first press part and the second press part respectively forming two electrodes between which the high frequency magnetic field is created and in which the interface sheet (IT) is in a thermoplastic material configured to be thermally deformed by the high frequencies of the magnetic field in order to ensure welding from the interface sheet to the cap and the 3D tangle of fibers (5) of the padding (3).

[Claim 3] Method according to claim 2, in which the first press part (P41) being configured to come to bear against the cap (CF) via a support wall, and the second press part (PR2) being configured to come to bear against the padding (3), and in which the support wall of the first press part (PR1) has an embossing configured to ensure superficial relief of the face of the assembly covered by the cap, in /G5/ when said assembly jointly undergoes:

- said compression between the first press part (PR1) and the second press part (PR2),

- the high frequency magnetic field causing the softening of the thermoformable interface (IT) sheet.

[Claim 4] Method according to one of claims 2 or 3 in which the interface sheet the sheet (IT) is in a material chosen from or comprising derivatives of polyvinyl chloride (PVC), polyurethane (PU) and polyamides (PA).

[Claim 5] Manufacturing method according to one of claims 2 to 4, in which the interface sheet (IT) is of thickness less than the thickness at the cap (CF) and the thickness of the padding (3), in particular less than 2mm.

[Claim 6] Manufacturing method according to one of claims 1 to 5, in which the 3D tangle of continuous fibers of the padding comprising in whole or in part:

-the fibers are hollow fibers (5a) and/or solid fibers (5b), with a diameter of between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm, and/or

- the fibers (5) comprise a thermoplastic polymer, the composition of the fibers comprising at least 95% by weight of PET, and/or in which the 3D entanglement of the padding (5) has an apparent density of between 30 kg/ m ³ and 70 kg/m ³ , more particularly between 45 kg/m ³ and 65 kg/m ³ ..

[Claim 7] Manufacturing method according to one of claims 1 to 6, in which in /G1/, the supply of the padding (3) comprising the 3D entanglement of thermoplastic fibers (5) comprises:

- /A/ Extrusion of a thermoplastic polymer in an extrusion die (6) comprising extrusion nozzles (60) distributed in a lengthwise direction (X6) and in a width direction (Y6) of the die 'extrusion, generating a curtain of continuous melted fibers (), falling by gravity,

- /B/ Receiving the curtain of molten continuous fibers falling by gravity against a shaping means, with generation of a 3D tangle of fibers (5) according to an irregular distribution with fusion of loops between the continuous fibers,

[Claim 8] Manufacturing method according to one of claims 1 to 7 in which the cap (CF) covers a front face (FF) of the padding (3), and in the front face of the padding provided in /G1/ is in relief comprising lateral flanges (Bl) projecting relative to a central part (PC), on either side of the central part (PC), the lateral flanges (Bl) configured to ensure the lateral maintenance of the occupant of the packing element.

[Claim 9] Seat lining element capable of being obtained by the manufacturing process according to one of claims 1 to 8 comprising in superposition (CF), a cap (CF), an interface sheet (IT) and a padding (3) comprising a 3D tangle of continuous fibers (5), and in which:

- the continuous fibers (5) are hollow fibers (5a) and/or solid fibers (5b), with a diameter of between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm,

- the continuous fibers (5) comprise a thermoplastic polymer, the composition of the fibers comprising at least 95% by weight of PET, and in which the 3D entanglement of the padding (5) has an apparent density of between 30 kg/m ³ and 70 kg/m ³ , and more particularly between 45 kg/m ³ and 65 kg/m ³ , and in which the cap (CF) is secured to the continuous fibers (5) of the 3D entanglement via the interface sheet (IT) welded jointly to the cap (CF) and to the continuous fibers (5) of the padding (3).

[Claim 10] Vehicle seat (1) comprising:

- a metal structure (2) comprising in particular a seat frame (20) and a backrest frame (21),

- a seat upholstery element (EG) according to claim 9 coupled to the metal structure (2), in particular a seat upholstery element coupled to the seat frame (20) and/or a backrest upholstery element coupled to the backrest frame (21).