Method for manufacturing a seat upholstery element comprising padding, a cover over the padding and a welded interface sheet.

Abstract

This disclosure relates to a method for manufacturing a seat upholstery component (EG) comprising: / G1 / supplying a padding (3) comprising a 3D entanglement of continuous thermoplastic fibers (5), irregularly arranged to form loops welded together, / G2 / supplying a cover (CF), / G3 / supplying an interface sheet (IT), / G4 / forming an assembly (ASS) comprising three successive layers in superposition, including the padding (3), the cover (CF), and said interface sheet (IT) interposed between the cover (CF) and the padding (3), / G5 / joining the three layers of the assembly by welding, at least by compression of the assembly between a first press part (PR1) and a second press part (PR2) in a tooling (OTS). Abstract figure: Figure 9

Description

Title of the invention: Method for manufacturing a seat upholstery element comprising padding, a cover over the padding and a welded interface sheet.

[0001] This 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 bonded to the continuous fibers of the 3D entanglement by means of the interface sheet welded jointly to the cap and the continuous fibers of the padding.

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

[0003] The present disclosure relates to the field of motor vehicle seats comprising a metal structure, typically with a seat frame and a backrest frame. The structure is conventionally obtained by stamping techniques. The seats also include padding, including a seat cushion layer and a backrest cushion layer, which provide softness to the seat and backrest and contribute to seating comfort. Previous technique

[0004] The seat and back cushions are generally made of urethane polymer foam and shaped in molds. Polyurethane foam cushions are 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 for manufacturing a seat upholstery component comprising: / Gl / supply of a padding comprising a 3D entanglement of continuous thermoplastic fibers arranged irregularly, forming loops welded together, / G2 / provision of a headgear, / G3 / provision of an interface sheet, / G4 / formation of an assembly comprising three successive layers in superposition, including the padding, the cap and said interface sheet interposed between the cap and the padding, / G5 / joining by welding of the three layers of the assembly at least by compression of the assembly between a first part of the press and a second part of the press in a tooling.

[0007] According to optional features of this disclosure, taken alone or in combination;

[0008] According to one embodiment, the tooling is a 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 / the three layers of the assembly are joined by high-frequency welding by subjecting the compressed assembly to a high-frequency magnetic field between 20 kHz and 70 kHz, the first press part and the second press part forming respectively two electrodes between which the high-frequency magnetic field is created and in which the interface sheet is made of 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 fiber entanglement of the mattress;

[0009] According to one embodiment, the first press part being configured to bear against the crown by means of a support wall, and the second press part being configured to bear against the padding, and wherein the support wall of the first press part may have an embossing configured to ensure a superficial relief of the face of the assembly covered by the crown, in / G5 / when said assembly undergoes joint: - said compression between the first press section and the second press section, - the high-frequency magnetic field which causes the softening of the thermoformable interface sheet;

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

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

[0012] According to one embodiment, the 3D entanglement of continuous fibers of the padding comprises, in whole or in part: -the fibers are hollow fibers and / or solid fibers, with a diameter 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 fiber composition comprising at least 95% by weight of PET, and / or in which the 3D entanglement of the padding (5) has an apparent density between 30 kg / m3 and 70 kg / m3, more particularly between 45 kg / m3 and 65 kg / m3.

[0013] According to one embodiment, in / Gl / , the supply of the padding comprising the 3D entanglement of thermoplastic fibers includes: - / A / 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, - / B / Reception of the curtain of continuous fused fibers falling by gravity against a shaping means, with the generation of a 3D entanglement of fibers according to an irregular distribution with fusion of loops between the continuous fibers, - / C / Solidification of the 3D fiber entanglement by immersion in a cooling fluid.

[0014] According to one embodiment, the headgear covers a front face of the padding, and in the front face of the padding provided in / Gl / is in relief comprising lateral tubes projecting from a central part, on either side of the central part, the lateral tubes configured to ensure the lateral support of the occupant of the padding element.

[0015] According to a second aspect, the present disclosure relates to a seat upholstery element obtainable by the manufacturing process according to the present disclosure, comprising, in superposition, a cover, an interface sheet, and padding comprising a 3D entanglement of continuous fibers, and in which: - Continuous fibers are hollow and / or solid fibers, with a diameter between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm, - continuous fibers comprise a thermoplastic polymer, the fiber composition comprising at least 95% by weight of PET, and in which the 3D entanglement of the padding (5) has an apparent density 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 joined to the continuous fibers of the 3D entanglement via the interface sheet (welded jointly to the cap and 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 this 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 features, details and advantages will become apparent upon reading the detailed description below and analyzing the accompanying drawings, in which: Fig. 1

[0018] [Fig.1] is a view of a motor vehicle seat, according to this 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 not being shown. Fig. 2

[0019] [Fig.2] is a cross-sectional view of the seat of [Fig.1], to which a ma is added backrest padding, and seat padding, according to this 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 enabling the production of the 3D tangle comprising an extrusion of a thermoplastic polymer in an extrusion die generating a curtain of continuous molten fibers, falling by gravity, the reception of the curtain of continuous molten fibers between two counter-rotating calendering members, with a generation of a 3D tangle of fibers and the solidification of the 3D tangle of fibers by immersion in a coolant, then the obtaining of padding by transverse cuts in the direction of scrolling. Fig. 4

[0021] [Fig.4] illustrates different extrusion dies that can be implemented according to The process of this disclosure, namely an extrusion die comprising extrusion nozzles for extruding solid fibers to obtain padding from solid fibers according to a first possibility, an extrusion die comprising extrusion nozzles for extruding hollow fibers to obtain padding from solid fibers according to a second possibility, and a mixed extrusion die comprising extrusion nozzles for extruding hollow fibers and extrusion nozzles for extruding solid fibers according to a third possibility, enabling the obtaining of padding comprising, depending on the thickness, a lower structural underlayer, formed of an entanglement of hollow fibers, upper soft underlayer, formed of an entanglement of solid fibers, and an intermediate bonding underlayer between the lower and upper underlayers. Fig. 5

[0022] [Fig.5] is a view of a production line comprising successively: - equipment configured for the implementation of the process according to [Fig.3], comprising an extrusion of a thermoplastic polymer in an extrusion die generating a curtain of continuous molten fibers, falling by gravity, the reception of the curtain of continuous molten fibers between two counter-rotating calendering elements, with a generation of a 3D fiber entanglement and the solidification of the 3D fiber entanglement by immersion in a coolant, - a workstation configured for performing transverse cuts to obtain separate and distinct padding layers of constant thickness - a carousel, comprising on a frame, rotating around a vertical axis, a plurality of thermoforming tools, each comprising a lower mold part and an upper mold part, the thermoforming tooling configured to follow a sequence, from a tooling opening position, the sequence synchronized with the rotation of the carousel, discontinuous, comprising a first position unloading / loading a cushion, a second position closing the tooling with compression and heating in order to obtain the thermoforming of the cushioning, a third position cooling, and a fourth position opening the tooling, - a packing station for the thermoformed mattress. Fig. 6

[0023] [Fig.6] shows a view of equipment configured for implementing the process according to this disclosure, comprising: - an extrusion die comprising nozzles distributed along a longitudinal direction and along a transverse direction of the extrusion die, generating a curtain of continuous molten 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 continuous molten fibers falling by gravity into the molding cavity of the molding tool so as to generate a 3D entanglement of fibers according to an irregular distribution with fusion of loops between the continuous fibers, - guides allowing the molding tooling to descend into a reservoir containing a coolant that ensures the solidification of the entanglement, - a logic processing unit comprising a control module with a microprocessor and memory configured for controlling the extrusion nozzles, and for motorized control of the descent of the molding tooling into the coolant. Fig. 7a

[0024] [Fig.7a] illustrates a first phase of the process in which the pilot logic unit the nozzles so as to fill only the recessed reliefs of the molding cavity, on either side of a central portion of the molding cavity, the nozzles of the extrusion die located at the right of the protruding 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, following the first phase, for which The logic unit opens all the extrusion nozzles so that the curtain of molten fibers covers the entire surface of the molding cavity in both the longitudinal and transverse directions of the molding cavity. Fig. 7c

[0026] [Fig.7c] shows a third phase, following the second phase, for which The logic unit opens only nozzles so that the curtain of molten fibers fills the central portion of the molding tooling located between the two recessed reliefs, in order to form on the dorsal face of the padding, a central portion protruding in relation to two lateral portions of the dorsal face. Fig. 7d

[0027] [Fig.7d] shows on the left a moment of third phase following [Fig.7c], and on the right, after demolding, a quilting formed of a 3D entanglement of fibers according to an irregular distribution with fusion of loops between the continuous fibers, the quilting having a front face shaped by the molding cavity of the molding tooling, and a back face not shaped by the molding tooling. Fig. 8

[0028] [Fig.8] is a view of a high-frequency welding tool comprising a first part of press, forming a positive electrode and a second part of press between which is compressed the assembly of the three layers comprising the cap, the interface sheet and the padding, to ensure the bonding of the cap to the padding, by welding the interface sheet jointly to the cap and to the continuous fibers of the 3D entanglement of the padding. Fig. 9

[0029] [Fig.9] is a left-hand view of the assembly elements, namely the headgear, the ma telassure and the interface sheet in the unassembled state, and to the right of the assembly of the elements via the thermoformable interface sheet, thermally deformed by the high frequencies of the tooling of [Fig.8]. Fig. 9a

[0030] [Fig.9a] is a detail and section view of the trim element of [Fig.9]. Fig. 10

[0031] [Fig. 10] is a schematic diagram illustrating the steps in the manufacturing process of the trim element. Fig. 11

[0032] [Fig. 11] is a seat structure, comprising a backrest frame and a seat frame, and on which can be coupled, an upholstery element according to this disclosure, in particular a backrest upholstery and a seat upholstery. Description of the implementation methods

[0033] The drawings and description below contain, essentially, elements of a definite nature. They may therefore not only serve to better understand this disclosure, but also contribute to its definition, if necessary.

[0034] Also, this disclosure relates to a seat 1 comprising: - a metal structure 2, - a filling element comprising a sure 3 mattress covered by a CF cover.

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

[0036] In [Fig.2], an XYZ reference frame is illustrated, the X direction oriented along the sliding direction of slide G between the seat structure 2 and a floor of the vehicle, the Y direction oriented along a transverse direction of the seat, and the Z direction along the vertical.

[0037] 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 comprises: - two side flanges, extending from a rear edge of the seat to a front edge, along the X direction, or slightly inclined with respect to the longitudinal X direction (for example, by plus or minus 30 degrees) around a transverse axis, and - a front piece, connecting the two front ends of the flanges, and extending along the transverse direction. The front piece and the flanges can advantageously be formed sheets, for example, by deep drawing techniques such as those illustrated in figures 1 and 2. In [Fig. 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.

[0039] The backrest frame comprises side uprights extending vertically, as well as a top crossbar connecting the two upper ends of the uprights. The uprights and the top crossbar are advantageously made of sheet metal formed, for example by stamping techniques.

[0040] The padding 3 includes a seat padding layer 3a which provides seating comfort and which can be received on a seat interface 4a interposed between the seat frame 20 according to the embodiment of [Fig. 2]. The padding 3 also includes a backrest padding layer 3b which provides backrest comfort and which is received on a backrest interface 4b, interposed between the backrest frame 21 and the backrest padding layer 3b.

[0041] The padding 3, in particular the seat padding layer 3a and / or the back padding layer 3b, comprises a three-dimensional (in "3D") entanglement 30 of continuous, thermoplastic fibers 5, arranged irregularly, forming loops welded together between the fibers 5.

[0042] The fibers can be hollow fibers 5a and / or solid fibers 5b. 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" means that the fibers are much longer than their diameter, and, due to the processes described below, typically by a ratio of at least 100, or even 500, or even 1000, and in particular due to the manufacturing process described below. Often, and because of this, the fibers 5 extend continuously from one edge of the padding to the other.

[0043] The fibers 5 comprise a thermoplastic polymer, the fiber composition preferably comprising at least 95% by weight of PET. For example, the fiber composition, or even the padding composition, comprises: - 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 (trimethylene terephthalate) or PBT (polybutylene terephthalate). The sum of PET and PTT (or PBT) can make up 100% by weight of the fibers, or even of the padding.

[0044] Preferably, the gaps between the fibers 5 of the 3D fiber entanglement 5 of the padding 3 are left free. This results in a structural and breathable padding, due to the numerous inter-spaces between the fibers which promote air circulation.

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

[0046] In [Fig. 2], the backrest padding layer 3b extends lengthwise along a longitudinal direction Xb from a lower edge to an upper edge of the backrest, and widthwise along a transverse direction Yb from a first lateral edge to a second lateral edge, as well as thicknesswise along an orthogonal direction Zb which is orthogonal to the longitudinal and transverse directions of the backrest. The thickness of the backrest padding layer can be from 30 mm to 60 mm.

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

[0048] Generally, the interface 4, in particular the seat interface 4a or the backrest interface 4b, may include a shell. The shell may 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 to a final position of lumbar kyphosis, 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 displacement control links 41s, and lower displacement control links 41i.

[0050] The upper displacement control links 41s and / or the lower displacement control links 41i are typically articulated links which may include connecting rods.

[0051] It is noted that the apparent density of the 3D entanglement of continuous fibers 5 is between 30 kg / m3 and 70 kg / m3, 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] Two manufacturing processes are now described for obtaining the 3D entanglement 30 of continuous fibers.

[0053] A first manufacturing process, as schematically illustrated in [Fig.3] understand : - / A / Extrusion of a thermoplastic polymer in an extrusion die 6 comprising extrusion nozzles 60 distributed along a lengthwise direction X6 and along a widthwise direction Y6 of the extrusion die, generating a curtain of continuous molten fibers 50, falling by gravity; - / B / Reception of the curtain of continuous fused fibers falling by gravity against a shaping means, with the generation of a 3D entanglement of fibers 5 according to a random distribution with fusion of loops between the continuous fibers, in particular according to a layer of thickness determined by the shaping means. Thus, the fibers are arranged irregularly, as already described. According to this process, the shaping means comprises two counter-rotating calendering elements 7, 8. The center distance ETR between the two counter-rotating elements 7, 8 delimits the thickness of the entanglement piece; - / C / Solidification of the 3D fiber entanglement by immersion in a fluid, for example LF coolant, such as water.

[0054] The extrusion nozzles 60 are preferably distributed regularly along the length direction X6 of the extrusion die, and also in width along the width direction Y6.

[0055] The thickness of the padding 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 elements 7, 8 are rotated at a speed typically lower than the fiber settling speed, ensuring fiber accumulation that leads to the random formation of loops which heat-weld each other, generating the irregular three-dimensional entanglement. Solidification in / C / is achieved immediately after step / B / , the two guiding elements being able to be immersed halfway for this purpose.

[0057] The extrusion temperature implemented in / A / in the extrusion die is typically between 180°C and 240°C. The extrusion die is fed with polymer granules.

[0058] 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-sectional cuts, allowing the production of different quilting patterns comprising 3D tangles. These quilting patterns extend lengthwise, for example lengthwise along the longitudinal direction Xa of the seat quilting layer (or lengthwise along the longitudinal direction Xb of the backrest quilting layer), typically along the direction transverse to the movement of the layer.

[0059] According to one embodiment, the apparent density can be homogeneous depending on the length and width of the layer, and as illustrated in [Fig. 5], top. The density of the number of extrusion nozzles is thus homogeneous along the longitudinal direction of the extrusion die.

[0060] According to another embodiment not illustrated, the extrusion die 6 may include, along the length direction X6 of the extrusion die, several distinct zones comprising distinct surface densities of number of nozzles, including at least a first 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 process 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 longitudinal direction X6 of the extrusion die.

[0062] Thus, and possibly: - the resulting padding layer of the seat 3a can thus comprise different zones with different apparent densities, depending on the longitudinal direction Xa of the padding layer of the seat 3a and / or, - the resulting backrest padding layer 3b can thus comprise different zones with different apparent densities, distributed along the longitudinal direction Xb of the backrest padding layer 3b.

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

[0064] According to another embodiment, the extrusion die may include extrusion nozzles configured for the extrusion of hollow fibers only, and as illustrated at the bottom right in [Fig.4], allowing the production 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 [Fig.4] on the middle view, the extrusion die 6 can include, according to the width dimension Y6 of the extrusion die, a first section 60a provided with first extrusion nozzles for the generation of hollow fibers 5a which extend lengthwise 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 lengthwise along the length of the die 6.

[0067] As illustrated in the right-hand view in [Fig. 4], the seat padding layer 3a and / or the backrest padding layer 3b may comprise, depending on the thickness: - a lower, structural sublayer, formed from an entanglement of hollow fibers 5a thick (Epinf), - a soft, top underlayer made of an intertwining of solid Epsup fibers, - an intermediate sub-layer between the lower sub-layer and the upper sub-layer, of bonding comprising an entanglement of solid and hollow fibers welded together, of thickness Epint.

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

[0069] In general and in [Fig.4], the thickness Epsup of the upper sublayer formed by the solid fibers 5b, is less than the thickness Epinf of the structural sublayer, formed by the hollow fibers 5a.

[0070] It is noted that this first embodiment applies in particular to the interlocking piece 30 of [Fig.3].

[0071] The 3D entanglement of continuous fibers, obtained at the end of the process of [Fig.3] is of constant thickness because the calendering elements 7,8 are elements with 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 entanglement of continuous fibers is compressed, the mold parts being heated.

[0073] The manufacturing process for the quilting can be implemented in a view of a production line comprising successively, according to the direction of processing: - equipment configured for the implementation of the process according to [Fig.3], comprising an extrusion of a thermoplastic polymer in an extrusion die 2 generating a curtain R of continuous molten fibers, falling by gravity, the reception of the curtain of continuous molten fibers between two counter-rotating calendering elements, with a generation of a 3D fiber entanglement and the solidification of the 3D fiber entanglement by immersion in a coolant, - a cutting station configured for performing transverse cuts to obtain separate and distinct padding, - a CAR carousel, comprising on a chassis, rotating around, a plurality of thermoforming tools, each comprising a lower mold part and an upper mold part, the thermoforming tooling configured to follow an operating sequence, synchronized with the discontinuous rotation of the carousel, - an EMB packaging station for the thermoformed mattress.

[0074] The mattress scraps at the cutting station can be ground / shredded and recycled at the inlet of the extrusion die, and as illustrated by an arrow in [Fig.3].

[0075] The carousel is driven by discontinuous material rotation. The thermoforming tooling comprises 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 unloading / loading position for a cushion in which the upper and lower mold parts are separated allowing the extraction of a thermoformed cushion or the insertion of a non-thermoformed cushion by an operator (or a robotic system), a second closing position of the tooling with compression of the cushion and heating in order to obtain the thermoforming of the cushion to a desired shape, typically in relief, a third cooling position, and a fourth opening position of the tooling.

[0077] According to a variant of the embodiment, not illustrated, in particular an alternative to the relief by thermoforming, the shaping of the padding and the 3D interlocking can be obtained by choosing calendering elements 7, 8 advantageously presenting a calendering wall that is then non-cylindrical, and contrary to the example illustrated in [Fig.3], and so as to calender a front face of the padding that is not flat, for example having a central portion PC and lateral rolls Bl.

[0078] According to a second embodiment of the manufacturing process for the padding, the shaping means includes a molding tool OM comprising a molding cavity CAV.

[0079] This second embodiment is now detailed with reference to figures 6 and 7a to 7d.

[0080] Equipment configured for implementing the process according to this disclosure, illustrated in [Fig. 6], may include: - an extrusion die 6 comprising nozzles 60 distributed along a lengthwise X direction and along a widthwise Y (transverse) direction of the extrusion die, configured to generate a curtain of continuous fused fibers, falling by gravity, - the molding tooling OM comprising the molding cavity CAV, open towards the extrusion die 6, directly above the extrusion die, the tooling being configured to receive the curtain R of continuous molten fibers falling by gravity into the molding cavity CAV of the molding tooling OM so as to generate a 3D entanglement of fibers according to an irregular distribution with fusion of loops between the continuous fibers, - possibly G guides allowing the molding tooling to descend into a reservoir containing a coolant, - a logic processing unit U comprising a microprocessor and a memory containing control instructions. The instructions can be configured to control the extrusion nozzles, or even to control the descent of the molding tooling 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 tooling being positioned vertically in line with the extrusion die.

[0082] The molding cavity extends between Fil flanks, F12, F13, FL4, in particular two end flanks Fil and F13 at two longitudinal ends of the molding tooling, spaced along the length direction X and two lateral flanks on the sides of the molds spaced along the width direction Y.

[0083] The extrusion nozzles 60 are distributed along the lengthwise X direction and along the widthwise Y direction of the extrusion die. The nozzles 60 are configured according to a matrix to generate at least temporarily a curtain of continuous fused fibers covering the entire surface of the mold cavity, extending from one side of the mold to the other, namely a curtain extending from one end side Fil to the other end side F12 along the lengthwise X direction and extending from one side side FL2 to the other side side FL4 along the widthwise Y direction.

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

[0085] Said logic processing unit U then preferably comprises a control module including a microprocessor and a memory containing instructions for, in / A / , controlling the nozzles so as to generate a curtain of fibers, of variable shape during extrusion. Such control makes it possible to generate quilting, in particular of complex shape, having in particular a thickness along the vertical direction Z, which can be variable along the longitudinal direction X, and / or variable along the transverse direction Y in the molding tooling.

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

[0087] The STL file is transmitted to the control module of logic unit U. The The control module cuts the padding into slices of typically fixed thickness along the vertical Z direction. During manufacturing, the control module drives 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 tooling during extrusion in order to obtain a complex-shaped mattress which has a front face FF (molded by the molding cavity) notably comprising lateral tubes B1 projecting from 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 padding geometry guaranteeing good lateral support of the occupant.

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

[0091] Such a geometry of the dorsal face FD can be configured to fit in support on 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 for manufacturing a MAT seat cushion, such as a seat or back cushion, and in which the cushion is obtained comprising the 3D interlocking piece, 30, of continuous thermoplastic fibers, irregularly arranged forming loops welded together by: - / A / Extrusion of a thermoplastic polymer in the extrusion die 6 comprising extrusion nozzles 60 distributed along a lengthwise direction X and along a widthwise direction Y of the extrusion die, generating a curtain R of continuous molten fibers, falling by gravity, - / B / Reception of the curtain of continuous molten fibers falling by gravity into the CAV molding cavity of the OM molding tooling so as to generate a 3D fiber entanglement with an irregular distribution and fusion of loops between the continuous fibers, said 3D fiber entanglement being conformed to said molding cavity, - / C / Solidification of the 3D fiber tangle conformed to the molding cavity by immersion in an LF coolant.

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

[0094] Figures 7A and 70B disclose, by way of example, a mold section following a plane YX, presenting a base with a raised relief RS on a central portion of the section, and two recessed reliefs RC, on either side of this central portion along the Y direction. Such recessed reliefs can be shaped for the molding of the side tubes Bl. These side tubes project from a central part PC of the padding from the front face FF.

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

[0096] Thus in [Fig.7a], the extrusion begins, in a first phase, with the generation of a curtain of molten fibers in two distinct parts which come to fill only the two hollow reliefs RC for the molding of the lateral coils, and not a central part of the tooling between these two reliefs.

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

[0098] Thus, and advantageously, the bottom of the mold may comprise: - a central portion, following a raised relief RS, configured to conform a central part PC of a front face FF of the padding facing the seat occupant, intended to receive the user's buttocks for the seat padding or the occupant's back for a backrest padding, and - lateral portions, on either side of the central portion, following two recessed reliefs RC, configured so as to form two lateral rolls BL of the padding, projecting from the central part PC, on the front face FF, the lateral rolls configured to ensure lateral support of the occupant.

[0099] According to one embodiment, in / A / , at least on 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 central portion of the molding tooling, so as to form on a dorsal face FD of the padding, opposite to the front face, a central portion PCE protruding in relation to lateral portions PL of the dorsal face FD, located on the back of the two lateral tubes BL.

[0100] Thus, in figures 7C and 7D, it is noted that the logic unit U controls the nozzles, on a third phase following the second phase, so as to generate a curtain of molten fibers which comes to fill the raised relief RS on the central portion of the bottom, and not the two recessed reliefs RC.

[0101] Such a geometry of the dorsal face FD, comprising a central portion PCE in protrusion (along the Z direction) relative to lateral portions PL can allow integration of the mattress sure 3 on the structure 2.

[0102] Generally, in / C / the solidification of the 3D fiber entanglement can be obtained by immersion in a coolant with control of the displacement of the molding tooling relative to a free surface SL of the coolant.

[0103] The free surface SL can be moved by motor to obtain the solidification of the 3D entanglement by immersion in the coolant LF, progressively during additive manufacturing, after the reception of the curtain of continuous fused fibers falling by gravity into the molding cavity, and preferably with a duration of less than 4s between the reception of the curtain of fibers generating the 3D entanglement, and the 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 coolant can be obtained by motorizedally plunging the molding tool OM into a tank containing the coolant.

[0105] In general, the logic processing unit U, in particular its control module, can control and synchronize the piloting of the nozzles 20 and the motorized movement of the free surface SL of the coolant.

[0106] Generally, the nozzles 60 may include 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 curtain fibers, namely for example solid fibers, for example on a first phase of extrusion, then hollow fibers on a second phase of extrusion.

[0108] Preferably, solid fibers can be used superficially on the front face FF intended to be in contact with the seat occupant in order to form a first "soft" layer, and preferably hollow, "structural" fibers on the rest of the thickness of the padding below this first layer to form a structural underlayer.

[0109] This disclosure further relates to a method for manufacturing an EG seat upholstery component comprising: / Gl / supply of a padding 3 comprising a 3D entanglement of continuous thermoplastic fibers 5, irregularly arranged forming loops welded together, / G2 / provision of a CF helmet, / G3 / provision of an IT interface sheet / G4 / formation of an ASS assembly comprising three superimposed layers accessories including padding 3, the CF cover and said IT interface sheet interposed between the CF 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 part of press PR1 and a second part of press PR2 in an OTS tooling.

[0110] In general, the padding 3 may include all or part of the following features: -the fibers are hollow fibers 5a and / or solid fibers 5b, with a diameter between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm, and / or - Fibres 5 comprise a thermoplastic polymer, the fibre composition comprising at least 95% by weight of PET, and / or in which the 3D entanglement of the padding (5) has an apparent density between 30 kg / m3 and 70 kg / m3, and in particular between 45 kg / m3 and 65 kg / m3.

[0111] Generally, in / Gl / , the supply of the padding 3 comprising the 3D entanglement of thermoplastic fibers 5 includes: - / A / Extrusion of a thermoplastic polymer in an extrusion die 6 comprising extrusion nozzles 60 distributed along a longitudinal direction X6 and along a widthwise direction Y6 of the extrusion die, generating a curtain of continuous molten fibers, falling by gravity, - / B / Reception of the curtain of continuous fused fibers falling by gravity against a shaping means, with the generation of a 3D entanglement of fibers (5) according to an irregular distribution with fusion of loops between the continuous fibers, - / C / Solidification of the 3D fiber entanglement by immersion in a cooling fluid.

[0112] The process can be that previously described and illustrated by way of example in [Fig. 2], in which the forming means are calendering elements 7, 8. The calendering elements 7, 8 can be cylindrical. The quilting can be embossed by thermoforming the quilting thus obtained. Alternatively, embossing of the quilting can be achieved by calendering elements having a non-cylindrical calendering wall.

[0113] The process can be described and illustrated by way of example in [Fig.6] in which the shaping means is a molding tool and whose molding cavity can allow for relief, in particular of the front face FF of the padding.

[0114] Thus, generally speaking, the front face FF of the padding provided in / Gl / , covered by the cover CF, is raised. The front face FF may therefore include lateral tubes B1 projecting from a central part PC, on either side of the central part PC, the lateral tubes B1 configured to ensure lateral support of the occupant of the garrison element.

[0115] The side rolls and the central part can be highlighted, according to the process described, by the shape of the calendering elements, or by successive thermoforming steps, or by the shape of the cavity of the molding tool OM 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 with the thighs / buttocks of the occupant for a seat trim element.

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

[0118] According to one embodiment, the tooling is a high-frequency welding tooling, which includes 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 by high-frequency welding by subjecting the compressed assembly to a high-frequency magnetic field between 20 kHz and 70 kHz, the first part of the press and the second part of the press forming respectively two electrodes between which the high-frequency magnetic field is created.

[0120] The IT interface sheet is made of 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 fiber entanglement 5 of the padding 3.

[0121] The interface sheet, the IT sheet, is made of a thermoplastic material that is compatible with high-frequency heating techniques. The material may be selected from or include polyvinyl chloride (PVC) derivatives, polyurethane (PU), polyamides (PA), or polyester derivatives.

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

[0123] The CF cover covers a front face FF of the padding 3, which can typically be in relief comprising lateral rolls B1 projecting from a central part P), on either side of the central part PC, the lateral rolls B1 configured to ensure lateral support of the occupant of the padding element. Such relief of the front face of the padding is typically provided in / Gl / .

[0124] OTS welding tooling can be used to shape the element of at least superficially upholstery. To this end, and generally speaking, the first press section P41 can be configured to bear against the CF cover via a support wall, and the second press section PR2 can be configured to bear against the mattress 3. The support wall of the first press section PR1 can then have an embossing configured to ensure a superficial relief of the face of the assembly covered by the cover, in / G5 / when said assembly undergoes joint: - said compression between the first press section PR1 and the second press section PR2, - the high-frequency magnetic field which causes the softening of the thermoformable IT interface sheet.

[0125] Figure 10 illustrates a diagram of the steps in the manufacturing process of the trim element, which includes the following steps: - at the opening stage OP, the welding tooling is opened by separating the first part of the press PR1 from the second part of the press PR2, - at the PS stage, the positioning of the cap / interface sheet / padding assembly between the two press parts PR1, "PR2, - at stage CL, the first press section PR1 and the second press section PR2 close, compressing the different layers of the assembly between them, - at the HT stage, in the tooling's closed position, a high-frequency magnetic field causes the thermoplastic interface sheet to rise in temperature until the CF cap is bonded to the padding 3, via the IT interface sheet, - At step OP, the high-frequency magnetic field source is switched off, then the first press part PR1 and the second press part PR2 are opened, to allow the extraction of the EG trim element.

[0126] This disclosure is further related to a seat trim element that can be obtained by the manufacturing process according to this disclosure.

[0127] Said padding element comprises, in superposition, a CF cap, an IT interface sheet and a padding 3 comprising a 3D entanglement of continuous fibers 5, and in which: - continuous fibers 5 are hollow fibers 5a and / or solid fibers 5b, with a diameter between 0.2 mm and 2 mm, preferably between 0.3 mm and 1.5 mm, - continuous fibres 5 comprise a thermoplastic polymer, the fibre composition comprising at least 95% by weight of PET, and in which the 3D entanglement of the padding (5) has an apparent density between 30 kg / m3 and 70 kg / m3; in particular between 45 kg / m3 and 65 kg / m3.

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

[0129] This disclosure is further related 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 this 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: Safe mattress, - 3a: Seat padding layer, - Xa, Ya, Za: Directions in length, width, and thickness of the seat padding layer, - 3b: Backrest padding layer, - 30. 3D fiber entanglement, - Xb, Yb, Zb: Directions in length, width, and thickness of the backrest padding layer, - 4: Interface, - 41s, 41i. Upper and lower displacement control links, - 5: Fibers, - 5a. Hollow fibers, - 5b. Solid 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 units - LF. Coolant.

Claims

Demands

1. Method for manufacturing a seat upholstery component (EG) comprising: / G1 / supply of a padding (3) comprising a 3D entanglement of continuous thermoplastic fibers (5) arranged irregularly 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) intercalated between the cap (CF) and the padding (3), / G5 / joining by welding the three layers of the assembly at least by compression of the assembly between a first part of press (PR1) and a second part of press (PR2) in a tooling (OTS). and wherein the tooling is a high-frequency welding tooling, comprising the first press part (PR1) and the second press part (PR2) between which the assembly is compressed, and wherein in / G5 / the three layers of the assembly are joined by high-frequency welding by subjecting the compressed assembly to a high-frequency magnetic field between 20 kHz and 70 kHz, the first press part and the second press part forming respectively two electrodes between which the high-frequency magnetic field is created and wherein the interface sheet (IT) is made of 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 fiber entanglement (5) of the padding (3).

2. A method according to claim 1, wherein the first press part (P41) is configured to bear against the cap (CF) by means of a support wall, and the second press part (PR2) is configured to bear against the padding (3), and wherein the support wall of the first press part (PR1) has an embossing configured to provide a surface relief of the face of the assembly covered by the cap, in / G5 / when said assembly undergoes joint: - said compression between the first part of the press (PR1) and the second part of the press (PR2), - the high-frequency magnetic field which causes the softening of the thermoformable interface (IT) sheet.

3. A method according to any one of claims 1 or 2 wherein the interface sheet (IT) is made of a material selected from or comprising polyvinyl chloride (PVC) derivatives, polyurethane (PU) and polyamides (PA).

4. A manufacturing method according to any one of claims 1 to 3, wherein the interface sheet (IT) is of a thickness less than the thickness of the cap (CF) and the thickness of the padding (3), in particular less than 2mm.

5. A manufacturing method according to any one of claims 1 to 4, wherein the 3D entanglement of continuous fibers of the padding comprises in whole or in part: - the fibers are hollow fibers (5a) and / or solid fibers (5b), of diameter 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 fiber composition comprising at least 95% by weight of PET, and / or wherein the 3D entanglement of the padding (5) has an apparent density between 30 kg / m3 and 70 kg / m3, more particularly between 45 kg / m3 and 65 kg / m3.

6. A manufacturing method according to any one of claims 1 to 5, wherein 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 along a lengthwise direction (X6) and along a widthwise direction (Y6) of the extrusion die, generating a curtain of continuous molten fibers (), falling by gravity, - / B / Reception of the curtain of continuous molten fibers falling by gravity against a shaping means, with a generation of a 3D entanglement of fibers (5) according to an irregular distribution with melting of loops between the continuous fibers, - / C / Solidification of the 3D entanglement of fibers by immersion in a cooling fluid.

7. A manufacturing method according to any one of claims 1 to 6 wherein the headgear (CF) covers a front face (FF) of the padding (3), and in which the front face of the padding supplied in / Gl / is in relief comprising lateral tubes (Bl) projecting from a central part (PC), on either side of the central part (PC), the lateral tubes (Bl) configured to ensure the lateral support of the occupant of the padding element.

8. A seat upholstery element obtainable by the manufacturing process according to any one of claims 1 to 7 comprising, in superposition (CF), a cover (CF), an interface sheet (IT) and padding (3) comprising a 3D entanglement of continuous fibers (5), and wherein: - continuous fibers (5) are hollow fibers (5a) and / or solid fibers (5b), with a diameter 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 fiber composition comprising at least 95% by weight of PET, and wherein the 3D entanglement of the padding (5) has an apparent density between 30 kg / m3 and 70 kg / m3, and more particularly between 45 kg / m3 and 65 kg / m3, and wherein the cap (CF) is bonded to the continuous fibers (5) of the 3D entanglement by means of the interface sheet (IT) welded jointly to the cap (CF) and to the continuous fibers (5) of the padding (3) and in which the interface sheet (IT) is of a thickness less than the thickness of the cap (CF) and the thickness of the padding (3), in particular less than 2mm, in a thermoplastic material 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 fiber entanglement (5) of the padding (3).

9. 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 8 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).

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