Interior trim panel of a motor vehicle

Abstract

The invention relates to an interior trim panel (1) for a motor vehicle, said panel comprising a body (2) including a cellular core (3), two facing layers (8) and backing layers (9) reinforcing said core, said facing layers being based on entangled reinforcing fibers embedded in polyurethane foam (16), and a coating layer (10) based on elastomeric polyurethane covering said facing layer, said panel further comprising a polyurethane sealing sheet (11) based on cellulose fibers, said sheet being disposed between said facing layer and said coating layer, said sheet being overmolded on both sides by the polyurethane foam and by the elastomeric polyurethane so as to be embedded between the two. Figure 1

Description

Title of the invention: Interior trim panel for motor vehicles

[0001] The invention relates to an interior trim panel for a motor vehicle and a method for making such a panel.

[0002] It is known to produce an interior trim panel for a motor vehicle, said panel comprising a body, said body comprising: • a cellular core, said core having a front face and a back face, said faces being connected to each other by a peripheral slice, said core having open cells opening on both sides towards said faces, • two front and back layers of reinforcement of said core, said layers being based on entangled reinforcing fibers, said layers being embedded in polyurethane foam, said layers extending respectively over said front and back faces, said foam overmolding said core so as to associate said layers with said core,

[0003] said panel further comprising a coating layer based on elastomeric polyurethane covering said front layer.

[0004] According to a known embodiment, the coating layer overmolds the front face so as to adhere to it.

[0005] Using polyurethane elastomer to make the coating layer makes it possible to have a waterproof layer, particularly robust in abrasion and easily washable.

[0006] Such an arrangement also makes it possible to produce a laminated panel with very good rigidity provided by a "beam effect" achieved by the reinforcing layers associated with each other via the core forming a means of spacing.

[0007] Such a panel is, for example, a shelf covering a luggage compartment or a false floor in the passenger compartment or luggage compartment.

[0008] However, because the cells of the core open on both sides towards the front and back faces, there is a risk during the production of such a panel that the polyurethane elastomer will pass through the front layer and penetrate into the core, possibly as far as the back layer which may itself be passed through by the polyurethane elastomer.

[0009] This results in overconsumption of polyurethane elastomer and also a risk of aesthetic defect on the reverse side of the panel.

[0010] The invention aims to propose an arrangement that overcomes these drawbacks.

[0011] To this end, and according to a first aspect, the invention proposes an interior trim panel for a motor vehicle, said panel comprising a body, said body comprising: • a cellular core, said core having a front face and a back face, said faces being connected to each other by a peripheral slice, said core having open cells opening on both sides towards said faces, • two layers of reinforcement for the front and back of said core, said layers being based on entangled reinforcing fibers, said layers being embedded in polyurethane foam, said layers extending respectively over said front and back faces, said foam overmolding said core so as to bond said layers to said core,

[0012] said panel further comprising a coating layer based on elastomeric polyurethane covering said front layer, said panel further having the following characteristics: • It also includes a polyurethane sealing sheet made from cellulose fibers, • said sheet is placed between said top sheet and said coating layer, • said sheet is overmolded on both sides by the polyurethane foam and by the polyurethane elastomer so as to be embedded between the two.

[0013] Such an arrangement implementing such a sealing sheet makes it possible to prevent the passage of polyurethane elastomer through the surface layer.

[0014] This results in the use of a minimized quantity of polyurethane elastomer and the absence of aesthetic defects on the reverse side of the panel.

[0015] In addition, the use of a sheet based on cellulose fibers has proven to be particularly suitable, especially compared to a sheet based on thermoplastic film.

[0016] Among the advantages observed by the applicant, the use of such a sheet based on cellulose fibers allows: • the absence of folds likely to disrupt the flow of the polyurethane elastomer precursor mixture, as such folds risk creating surface defects on the coating layer, • to smooth out any defects that might result from markings made by the core - for example in the form of a honeycomb pattern when said core presents such a structure - due to the quality of the sheet used (provided that it has a sufficient surface mass as mentioned later), • good homogeneity of the coating layer, which is ensured by the braking effect of the polyurethane elastomer precursor mixture as it flows over such a sheet, • excellent adhesion of the polyurethane elastomer and the polyurethane foam to the sheet, which contributes to the robustness of the panel.

[0017] According to a second aspect, the invention proposes a method for manufacturing such a panel.

[0018] Other features and advantages of the invention will become apparent in the following description, made with reference to the attached figure [Fig. 1], which is a schematic partial cross-sectional view of a panel according to one embodiment.

[0019] With reference to the figure, a panel 1 of interior trim for a motor vehicle is described, said panel comprising a body 2, said body comprising: • a cellular core 3, said core having a front face 4 and a back face 5, said faces being connected to each other by a peripheral slice 6, said core having open cells 7 opening on both sides towards said faces, • two layers of reinforcement for the front 8 and back 9 of said core, said layers being based on entangled reinforcing fibers, said layers being embedded in polyurethane foam 16, said layers extending respectively over said front and back faces, said foam overmolding said core so as to bond said layers to said core,

[0020] said panel further comprising a coating layer 10 based on elastomeric polyurethane covering said front layer, said panel further having the following characteristics: • it further comprises a polyurethane sealing sheet 11 based on cellulose fibres - in particular in the form of paper or cardboard - • said sheet is placed between said top sheet and said coating layer, • said sheet is overmolded on both sides by the polyurethane foam and by the polyurethane elastomer so as to be embedded between the two.

[0021] According to one embodiment, the core 3 is formed by a honeycomb structure.

[0022] According to various embodiments, the honeycomb is made of cardboard, thermoplastic material or aluminum.

[0023] According to the embodiment shown, the coating layer 10 further extends over the edge 6 of the core 3 and over a peripheral band 14 of the underside layer 9, so as to ensure extensive protection of the panel 1 - in particular in the event of water being spilled on it.

[0024] According to one embodiment, the sealing sheet 11 has a surface mass between 100 and 400 g / m2, and in particular between 250 and 300 g / m2, which gives it good strength allowing in particular the absence of folds and markings by the core 3.

[0025] According to various embodiments, the reinforcing fibers are mineral fibers - for example glass - or vegetable fibers - for example flax, cotton, or hemp.

[0026] According to one embodiment, the thickness of the coating layer 10 is between 0.5 and 2 mm, and in particular on the order of 1.5 mm.

[0027] According to one embodiment, a backing coating layer 15 - for example based on non-woven material - is glued or overmolded by the foam onto the backing layer 9.

[0028] According to one embodiment, the reinforcing fibers are linked together by a bonding agent, for example in the form of resin.

[0029] According to one embodiment, the reinforcing layers 8,9 have a surface mass between 200 and 500 g / m2, and in particular of the order of 450 g / m2.

[0030] A method for manufacturing such a panel 1 is now described, said method comprising the following steps: • provide a cellular core 3, said core having a front face 4 and a back face 5, said faces being connected to each other by a peripheral slice 6, said core having open cells 7 opening on both sides towards said faces, • Arrange two layers of reinforcement, one on the right side (8) and one on the wrong side (9), on each of the said faces, said layers being made of interwoven reinforcing fibers, • pour a precursor mixture of polyurethane foam 16 onto each of the said layers, • place the assembly in a first mold defining a first molding cavity, the wall of said cavity being lined opposite said facing layer with a sheet 11 made of cellulose fibers, • wait for the foam to expand so that said sheets are impregnated with foam, said foam overmolding said core, so as to join said sheets to said faces, said foam further overmolding said sheet, so as to join said sheet to said top sheet, • remove the entire mold and transfer it into a second mold defining a second molding cavity, said cavity defining a space of substantially homogeneous thickness between its wall and said sheet, • fill said space by injection with a precursor mixture of polyurethane elastomer so as to produce the coating layer 10, • demold said panel obtained.

[0031] According to one embodiment, the space is provided to extend further over the edge 6 of the core 3 and over a peripheral strip 14 of the reverse layer 9, so as to obtain a panel 1 whose coating layer 10 extends further over said edge and said strip.

[0032] It is also possible to associate at least one layer of reverse coating on the reverse layer, in particular by gluing or by overmolding with the foam in the first mold.

Claims

Demands

1. Interior trim panel (1) for a motor vehicle, said panel comprising a body (2), said body comprising: • a cellular core (3), said core having a front face (4) and a back face (5), said faces being connected to each other by a peripheral edge (6), said core having open cells (7) opening on both sides towards said faces, • two front (8) and back (9) reinforcement layers for said core, said layers being based on entangled reinforcing fibers, said layers being embedded in polyurethane foam (16), said layers extending respectively over said front and back faces, said foam overmolding said core so as to bond said layers to said core, said panel further comprising a coating layer (10) based on elastomeric polyurethane covering said front layer,said panel being characterized in that: • it further comprises a polyurethane sealing sheet (11) based on cellulose fibers, • said sheet is disposed between said top sheet and said coating layer, • said sheet is overmolded on both sides by the polyurethane foam and by the polyurethane elastomer so as to be embedded between the two.

2. Panel (1) according to claim 1, characterized in that the core (3) is formed by a honeycomb structure.

3. Panel (1) according to claim 2, characterized in that the honeycomb is based on cardboard, thermoplastic material or aluminum.

4. Panel (1) according to any one of the preceding claims, characterized in that the coating layer (10) further extends over the edge (6) of the core (3) and over a peripheral band (14) of the backing layer (9), so as to ensure extensive protection of said panel.

5. Panel (1) according to any one of the preceding claims, characterized in that the sealing sheet (11) has a surface mass between 100 and 400 g / m2.

6. Panel (1) according to any one of the preceding claims, characterized in that the reinforcing fibers are mineral fibers or vegetable fibers.

7. Panel (1) according to any one of the preceding claims, characterized in that the thickness of the coating layer (10) is between 0.5 and 2 mm.

8. A method for manufacturing a panel (1) according to any one of the preceding claims, characterized in that it comprises the following steps: • providing a cellular core (3), said core having a front face (4) and a back face (5), said faces being connected to each other by a peripheral edge (6), said core having open cells (7) opening on both sides towards said faces, • arranging two layers of reinforcement, front (8) and back (9), on each of said faces, said layers being based on entangled reinforcing fibers, • pouring a polyurethane foam precursor mixture (16) onto each of said layers, • arranging the assembly in a first mold defining a first molding cavity, the wall of said cavity being lined opposite said front layer with a sheet (11) based on cellulose fibers,• wait for the foam to expand so that said sheets are impregnated with foam, said foam overmolding said core, so as to join said sheets to said faces, said foam further overmolding said sheet, so as to join said sheet to said top sheet, • remove the entire mold and transfer it into a second mold defining a second molding cavity, said cavity defining between its wall and said sheet a space of substantially homogeneous thickness, fill said space by injection with a precursor mixture of polyurethane elastomer so as to produce the coating layer (10), demold said panel obtained.

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