Method for manufacturing a vehicle trim panel and trim panel thus obtained

Abstract

Method for manufacturing a vehicle trim panel and trim panel thus obtained. The invention relates to a method for manufacturing a trim panel, comprising the following steps: - supplying first (12) and second (14) end layers, the first end layer comprising an opening (32) with a closed contour; - supplying an injection mold (40) comprising a first (42) and a second (44) movable elements relative to each other, the first element comprising an injection orifice (50); then - arranging the first (12) and second (14) end layers in the first (42) and in the second (44) elements of the injection mold, the opening (32) being arranged around the orifice (50); then - injecting a foaming composition through the injection orifice (50), so as to fill the cavity with a foam; then solidifying the foam. Figure for the abbreviation: Figure 2

Description

Title of the invention: Method for manufacturing a vehicle trim panel and trim panel thus obtained

[0001] The present invention relates to a method for manufacturing a trim panel, in particular for a vehicle, said panel comprising: a first and a second end layer; and an intermediate layer disposed between said first and second end layers.

[0002] The invention applies for example to a door panel, a center console or dashboard covering of a vehicle.

[0003] The use of natural fibers in the manufacture of such trim panels is economically advantageous and reduces the carbon footprint of vehicles. The use of NFPP (Natural Fiber Polypropylene) material for vehicle trim panels is described in particular in document FR2300545, not yet published, filed on behalf of the Applicant.

[0004] However, NFPP materials result in rigid components that may feel unpleasant to vehicle users. Furthermore, their rigidity and manufacturing process limit the possibility of creating specific shapes on their surface.

[0005] The present invention aims to provide a manufacturing process leading to a trim panel that is easy to assemble to a structure, while having an optimized mass, a pleasant feel and offering a wide variety of shaping.

[0006] To this end, the invention relates to a manufacturing process of the aforementioned type, comprising the following steps: supplying each of the first and second end layers, the first end layer comprising an opening with a closed contour; at least the first end layer comprising a plurality of natural fibers and a plastic matrix binding said fibers together; supplying an injection mold comprising a first and a second element, said first and second elements comprising respectively a first and a second molding surfaces, the first element comprising an injection orifice opening onto the first molding surface, said first and second elements being movable relative to each other, so that in an assembled configuration of the injection mold, a cavity is provided between the first and second molding surfaces;then the arrangement of the first end layer in the first element of the injection mold, so as to conform to the first molding surface, the opening of the first end layer being arranged around the injection orifice of the first element; the arrangement of the second end layer in the second element of the injection mold, so as to; conform to the second molding surface; then position the injection mold in the assembled configuration; then inject a foaming composition through the injection orifice, so as to fill the cavity with foam; then solidify the foam, so as to form the intermediate layer and to bond said intermediate layer with the first and second end layers.

[0007] According to other advantageous aspects of the invention, the manufacturing process comprises one or more of the following features, taken individually or in all technically possible combinations:

[0008] - the second end layer and the intermediate layer are deformable by reversible way;

[0009] - the first end layer and the first element of the injection mold include means for assembling one another, allowing the opening of the first end layer to be positioned around the injection orifice of the first element;

[0010] - the first end layer has a thickness between 1.8 mm and 2.5 mm;

[0011] - the natural fibers of the first end layer comprise fibers chosen from linen, hemp, kenaf, coconut, sisal, jute and / or wood fibers;

[0012] - the supply of the first end layer includes: a supply of a mat comprising the plurality of natural fibers; and compression forming of said mat, said forming leading to the polymerized matrix binding said fibers together;

[0013] - compression forming is hot compression thermoforming.

[0014] The invention further relates to a lining panel comprising: a first and a second end layer; and an intermediate layer disposed between said first and second end layers, said intermediate layer comprising a polymer foam; the first end layer comprising an opening with a closed contour; at least the first end layer comprising a plurality of natural fibers and a plastic matrix binding said fibers together. Preferably, the panel is produced by a manufacturing process as described above.

[0015] According to other advantageous aspects of the invention, the manufacturing process comprises one or more of the following features, taken individually or in all technically possible combinations:

[0016] - the second end layer and the intermediate layer are deformable by reversible way;

[0017] - the second end layer has an undercut shape.

[0018] The invention will become clearer upon reading the following description, given solely by way of non-limiting example and with reference to the drawings in which:

[0019] [Fig-1] [Fig.1] is a partial schematic cross-sectional view of a panel of vehicle upholstery according to an embodiment of the invention; and

[0020] [Fig.2] [Fig.2] is a partial schematic view, in section, of a manufacturing step of the trim panel of [Fig.1], according to an embodiment of the invention.

[0021] Figure 1 shows a trim panel 10 according to an embodiment of the invention. Such a trim panel is particularly intended for lining the interior of a vehicle, especially a motor vehicle. The panel 10 is, for example, an interior door panel, a dashboard trim, or a center console.

[0022] The panel 10 comprises: a first 12 and a second 14 end layers; and an intermediate layer 16.

[0023] In the embodiment shown, a first outer edge 20 of the first end layer 12 and a second outer edge 22 of the second end layer 14 are in contact with each other.

[0024] More specifically, the first 12 and second 14 end layers form respectively a first 24 and a second 26 outer surfaces of the trim panel 10. The first outer surface 24 is intended to be assembled to a component of the vehicle equipped with said panel 10. The second outer surface 26 is intended to be oriented towards the vehicle user(s), so as to be visible to the end user.

[0025] According to a preferred embodiment, the second outer surface 26 has one or more hollows 28 and / or one or more reliefs 29, 30.

[0026] With the exception of the outer edges 20, 22, the first 12 and second 14 end layers are separated from each other. The intermediate layer 16, described in more detail below, is arranged between the first 12 and second 14 end layers and is integral with each of said layers.

[0027] The first end layer 12 has a closed contour opening 32, leading to the intermediate layer 16. Preferably, the opening 32 is located at a distance from the first edge 20, as will be described below.

[0028] At least the first end layer 12 comprises: a plurality of natural fibers; and a first polymerized matrix, binding said fibers together.

[0029] Preferably, the natural fibers of the first end layer 12 comprise fibers selected from flax, hemp, kenaf, coconut, sisal, jute and / or wood fibers.

[0030] Preferably, the natural fibers of the first end layer 12 comprise recycled natural fibers.

[0031] According to one embodiment, the natural fibers of the first end layer 12 comprise fibers having a length between 30mm and 250mm.

[0032] According to one embodiment, the first end layer 12 further comprises synthetic fibers, mixed with natural fibers in the polymerized matrix. Preferably, said synthetic fibers are recycled.

[0033] According to one embodiment, the first polymerized matrix comprises at least one thermoplastic polymer or at least one thermosetting polymer.

[0034] Preferably, the first polymerized matrix comprises a polyolefin, more preferably a polypropylene.

[0035] According to one embodiment, the first end layer 12 has a thickness between 1.8 and 2.5 mm.

[0036] Preferably, the first end layer 12 has a certain rigidity, allowing the overall shape of the lining panel 10 to be given as well as its structural characteristics.

[0037] In one embodiment, the second end layer 14 comprises at least one plastic material. According to another embodiment, the second layer 14 may be a textile or a leather.

[0038] According to one embodiment, the plastic material of the second layer The end layer 14 comprises a compound selected from polyurethane, PVC (polyvinyl chloride), and thermoplastic elastomers such as TPO, TPV, or TPS.

[0039] Preferably, the second end layer 14 is soft and / or flexible, of so as to be reversibly deformable, as described below. In particular, the second end layer 14 preferably has a thickness between 0.6 and 4 mm

[0040] The intermediate layer 16 is formed of a foam filling an internal space 34, provided between the first 12 and second 14 end layers. The opening 32 of the first end layer 12 opens onto said space 34. Preferably, with the exception of said opening 32, the internal space 34 is closed, in particular by the contact between the external edges 20, 22 of the first 12 and second 14 end layers.

[0041] As described below, the intermediate layer is made from a foaming fluid composition, preferably comprising a polymerizable resin. More preferably, the fluid composition comprises at least one compound selected from polyurethanes and polypropylenes.

[0042] Preferably, the intermediate layer 16 is reversibly deformable, in particular by compression, as described below.

[0043] According to one embodiment, the intermediate layer 16 has a variable thickness on the filling panel 10, in particular so as to compensate for the hollow(s) 28 and / or relief(s) 29, 30 of the second outer surface 26, as described below.

[0044] Fig. 2 shows a step in a manufacturing process for the trim panel 10, according to an embodiment of the invention.

[0045] Said manufacturing step uses an injection mold 40. The mold 40 includes in particular a first 42 and a second 44 rigid elements.

[0046] The first 42 and second 44 elements of the mold 40 are movable relative to each other. We consider a direction X of displacement, along which the first 42 and second 44 elements are displaced relative to each other by translation.

[0047] The first 42 and second 44 elements of the mold 40 comprise respectively a first 46 and a second 48 molding surfaces. Said first 46 and second 48 molding surfaces are substantially complementary, respectively, to the first 24 and second 26 outer surface of the panel 10, as described below.

[0048] In the embodiment shown, the second molding surface 48 has at least one undercut shape 49 with respect to X. Said undercut shape corresponds for example to a relief 29, 30 of the second outer surface 26, or alternatively to a hollow of said second surface.

[0049] The first element 42 includes an injection orifice 50, opening onto the first molding surface 46. The orifice 50 is aligned with the opening 32 of the first end layer 12.

[0050] Preferably, the first mold element 42 further comprises a member 52 for connecting the injection orifice 50 to the opening 32 of the first end layer 12, as will be described below. In the embodiment shown, the first mold element 42 comprises a tube 52 arranged around the injection orifice 50 and projecting from the first molding surface 46. The tube 52 allows the first end layer to be positioned on the first mold element 42 of the mold 40.

[0051] In one embodiment, the tubing 52 includes a sealing gasket to prevent material leakage. In a complementary or independent embodiment, the tubing 52 is formed by the foaming head, i.e., by the element for injecting the foam precursor into the cavity.

[0052] A method for manufacturing the trim panel 10, according to an embodiment of the invention, will now be described.

[0053] A first step of said process is the supply of the first 12 and second 14 end layers previously described.

[0054] Preferably, the first end layer 12 is obtained by a process comprising: supplying a mat / blanket comprising a plurality of natural fibers; and compression forming said mat, said forming leading to the polymerized matrix bonding said fibers together. More preferably, the compression forming is hot compression thermoforming.

[0055] According to a preferred embodiment, the mat comprises natural fibers and at least a first group of polypropylene (PP) fibers. Such a material is known as NFPP for "Natural fibers polypropylene." The polypropylene fibers feed into the matrix during thermoforming.

[0056] According to another embodiment, the polymerized matrix is ​​obtained by injecting a precursor compound before or during the compression forming of the mat. Other methods for obtaining the first end layer 12 are also possible.

[0057] The opening 32 is obtained for example by cutting the part resulting from compression forming.

[0058] The second end layer 14 is obtained for example by rotary molding, also known under the English term "slush molding", by weaving etc.

[0059] In a second step of the process, the first 12 and second 14 end layers are arranged in contact, respectively, with the first 46 and second 48 molding surfaces of the mold 40. During this second step, the first 42 and second 44 elements of the mold 40 are separated from each other.

[0060] The opening 32 of the first end layer 12 is arranged around the tube 52 so that the injection orifice 50 coincides with said opening. In one embodiment, the first molding surface 46 is substantially oriented upwards, the first end layer 12 being held by gravity in contact with the first molding surface 46. Alternatively, the outer edge 20 of the first end layer 12 is mechanically fixed to the first mold element 42.

[0061] According to one embodiment, the second end layer 14 is vacuum-pressed against the second molding surface 48, so that the hollow(s) 28 and / or relief(s) 29, 30 of the second outer surface 26 are arranged in contact with the corresponding shapes of said second surface 48.

[0062] In a third step of the process, the first 42 and second 44 elements of the mold 40 are brought closer together, so as to bring into contact the first outer edge 20 of the first end layer 12 and the second outer edge 22 of the second end layer 14. The first 42 and second 44 elements then form an air gap corresponding to the internal space 34 between the first 12 and second 14 end layers.

[0063] In a fourth step of the process, a foaming fluid composition is injected into the air gap through the injection port 50. The foam expands and fills the internal space 34, in particular so as to conform to the hollow(s) 28 and / or relief(s) 29, 30 of the second external surface 26.

[0064] The foam polymerizes, so as to form the elastically deformable intermediate layer 16. The polymerization of the foam further bonds the intermediate layer with each of the first 12 and second 14 end layers.

[0065] After polymerization of the foam, a fifth demolding step is implemented. More specifically, the first 42 and second 44 elements of the mold 40 are separated from each other along X.

[0066] During the demolding step, the relief 30 of the second outer surface 26, corresponding to the undercut shape 49 of the second element 44, is reversibly deformed. In particular, the intermediate layer 16 is reversibly compressed during the movement of the second element 44 relative to the first element 42 of the mold. The relief 30 regains its shape when the first 42 and second 44 elements of the mold 40 are sufficiently separated from each other.

[0067] The demolding step is made possible by the flexibility of the second 14 end layer and by the compressibility of the intermediate layer 16.

[0068] The trim panel 10 described above is thus obtained. An additional step of cutting the external edges 20, 22 is optionally carried out before use of said panel.

[0069] Alternatively, the second end layer is located at the bottom during the process and the first end layer is located at the top. In addition, the entire mold can be tilted during the injection step to improve the flow of material during this step.

[0070] After installation of the panel 10 on a structure, the opening 32 of the first layer 12 is oriented towards said structure and is therefore not visible to users.

[0071] The process described above makes it possible to obtain a panel stiffened by the first end layer 12, which facilitates its assembly with a structure. The panel also has a pleasant feel and offers a wide variety of shaping possibilities, thanks to the flexible second end layer 14 and intermediate layer 16.

[0072] This process also makes it possible to increase the possibility of visible shapes on a part with an NFPP support. Due to its rigidity and manufacturing process, NFPP does not allow for much undercutting. The process described above makes it possible to add visible shapes, that is to say, on the second layer 14 end, undercut, while having a support without undercuts.

[0073] The intermediate foam layer 16 helps to optimize the weight of the panel 10. The presence of natural and / or recycled fibers in the end layers helps to reduce the vehicle's carbon footprint.

Claims

1. Demands A method for manufacturing a trim panel (10), particularly for vehicles, said panel comprising: a first (12) and a second (14) end layer; and an intermediate layer (16) disposed between said first and second end layers; the method comprising the following steps: - supply of each of the first (12) and second (14) end layers, the first end layer comprising an opening (32) with a closed contour; at least the first end layer comprising a plurality of natural fibres and a plastic matrix binding said fibres together; - supply of an injection mold (40) comprising a first (42) and a second (44) element, said first and second elements comprising respectively a first (46) and a second (48) molding surfaces, the first element comprising an injection orifice (50) opening onto the first molding surface, said first and second elements being movable relative to each other, so that in an assembled configuration of the injection mold, a cavity (34) is provided between the first and second molding surfaces; then - arrangement of the first end layer (12) in the first element (42) of the injection mold, so as to fit the first molding surface (46), the opening (32) of the first end layer being arranged around the injection orifice (50) of the first element; - arrangement of the second end layer (14) in the second element (44) of the injection mold, so as to conform to the second molding surface (48); then - arrangement of the injection mold in the assembled configuration; then - injection of a foaming composition through the injection orifice (50), so as to fill the cavity with a foam; then - solidification of the foam, so as to form the intermediate layer (16) and to bond said intermediate layer with the first and second end layers.

2. A manufacturing method according to claim 1, wherein the second end layer (14) and the intermediate layer (16) are reversibly deformable.

3. A manufacturing method according to claim 1 or 2, wherein the first end layer (12) and the first element (42) of the injection mold comprise means (52) for assembling each other, allowing the opening (32) of the first end layer to be positioned around the injection orifice (50) of the first element.

4. A manufacturing method according to any one of the preceding claims, wherein the first end layer (12) has a thickness between 1.8 mm and 2.5 mm.

5. A manufacturing method according to any one of the preceding claims, wherein the natural fibers of the first end layer (12) comprise fibers selected from flax, hemp, kenaf, coconut, sisal, jute and / or wood fibers.

6. A manufacturing method according to any one of the preceding claims, wherein the supply of the first end layer (12) comprises: a supply of a mat comprising the plurality of natural fibers; and compression forming of said mat, said forming leading to the polymerized matrix binding said fibers together.

7. A manufacturing method according to claim 6, wherein the compression forming is a hot compression thermoforming.

8. Upholstery panel (10) comprising: a first (12) and a second (14) end layer; and an intermediate layer (16) disposed between said first and second end layers, said intermediate layer comprising a foam of polymer material; the first end layer comprising an opening (32) with a closed contour; at least the first end layer (12) comprising a plurality of natural fibers and a plastic matrix bonding said fibers together.

9. Panel (10) of trim according to claim 8, wherein the second end layer (14) and the intermediate layer (16) are reversibly deformable.

10. Panel (10) of trim according to claim 8 or claim 9, wherein the second end layer (14) has an undercut shape (29, 30).

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