SKIN FOR A VEHICLE INTERIOR TRIM PART CONTAINING AN OPERATING ELEMENT

Abstract

The skin (1) comprises at least an outer elastomeric layer (5) with an inner surface and an outer surface and at least one operating element (8A) which is adhered to the inner surface of the outer skin layer (5). The operating element (8A) is intended to be connected to an electric or electronic component to enable to control the operation of this component. In order to indicate the location of the operating element (8A) in the skin (1) with a minimal distortion of the visual appearance of the skin, the operating surface (9) of the operating element (8A) extends in a first area (11) of the visible surface of said skin (1), which first area (11) has a first surface texture which is different from the surface texture of the surrounding area (12) of the visible surface of the skin. Both textures may in particular produce a different gloss and the first area (11) may further be provided with surface relief elements (16, 17).

Claims

1. A skin (1) for a vehicle interior trim part (2), which skin (1) comprises at least an outer elastomeric layer (5) with an inner surface (6) and an outer surface (7) and at least one operating element (8) which is adhered to the inner surface (6) of said outer layer (5) and which has an operating surface (9), the outer surface (7) of said outer elastomeric layer (5) forming the visible surface of the skin, characterised in that the operating surface (9) of said operating element (8) extends in a first area (11) of the visible surface of said skin (1) which is at least partially surrounded by a second area (12) of the visible surface of said skin (1), the outer surface (7) of said outer layer (5) having in at least a portion of said first area (11) a first surface texture and in said second area (12) a second surface texture which is different from said first surface texture.

2. The skin according to claim 1, characterised in that said operating element (8) is configured to be connected to an electric or electronic component to enable to control the operation of said component.

3. The skin according to claim 1 or 2, characterised in that the outer surface (7) of said outer elastomeric layer (5) has in said first area(11) at least one surface relief element (16, 17, 18) forming a visible sign indicating the presence of the operating surface (9) of said operating element (8), which surface relief element (16, 17, 18) comprises at least one depression in said outer surface (7), where the outer elastomeric layer (5) has a reduced thickness, and/or at least one elevation on said outer surface (7), where the outer elastomeric layer (5) has an increased thickness.

4. The skin according to claim 3, characterised in that said depression and/or elevation produces a height difference (h) on said outer surface (7) of at least 0.10 mm and preferably of at least 0.15 mm.

5. The skin according to claim 3 or 4, characterised in that at least a portion of the surface of said surface relief element (16, 17, 18) has said first surface texture.

6. The skin according to any one of the claims 3 to 5, characterised in that the outer surface of said outer layer has in at least a portion of said first area (11) next to said surface relief element (16, 17, 18) said first surface texture.

7. The skin according to any one of the claims 3 to 6, characterised in that said surface relief element (16, 17, 18) has a projected surface area on a flat plane tangent to the outer surface (7) of said outer elastomeric layer (5) of at least 1 mm.sup.2, preferably of at least 2 mm.sup.2.

8. The skin according to claim 1 or 2, characterised in that said portion of said first area (11) forms a visible sign indicating the presence of the operating surface (9) of said operating element (8).

9. The skin according to any one of the claims 1 to 8, characterised in that said second surface texture is visually distinct from said first surface texture.

10. The skin according to any one of the claims 1 to 9, characterised in that said second surface texture differs from said first surface texture to produce a difference in gloss value between the portion of said first area (11), which has said first texture, and the second area (12), which has said second surface texture, said second surface texture having in particular a different roughness and/or a profile with a different root mean square slope value than said first surface texture.

11. The skin according to any one of the claims 1 to 10, characterised in that said first surface texture is smoother than said second surface texture to provide a higher gloss to the portion of said first area (11) which has said first surface texture, the second area (12) of the skin (1) having in particular a gloss value, measured in accordance with ASTM D523-14(2018) under an angle of 60°, smaller than 2.0, more particularly smaller than 1.5.

12. The skin according to any one of the claims 1 to 11, characterised in that said skin (1) comprises an inner elastomeric layer (10) adhered to the inner surface (6) of said outer layer (5) with said operating element (8) being embedded in between said outer (5) and said inner layer (10).

13. The skin according to any one of the claims 1 to 12, characterised in that said operating element (8) comprises a sensor element (13).

14. The skin according to any one of the claims 1 to 13, characterised in that said operating element (8) comprises a light source (14).

15. The skin according to any one of the claims 1 to 14, characterised in that the visible surface of the skin (1) in said first area (11) and in said second area (12) is formed by one and the same material.

16. A vehicle interior trim part comprising a skin according to any one of the claims 1 to 15, which skin (1) is adhered to a substrate layer (3), in particular through the intermediary of a foam layer (4).

17. The vehicle interior trim part according to claim 16, characterised in that said operating element (8) is connected to an electric or electronic component.

18. A method for producing a skin according to any one of the claims 1 to 15, which method comprises the steps of: moulding said outer elastomeric layer (5) with its outer surface (7) against a mould surface, which mould surface is provided with a negative of said first surface texture to produce said first surface texture on the outer surface (7) of said outer elastomeric layer (5) and with a negative of said second surface texture to produce said second surface texture on the outer surface (7) of said outer elastomeric layer (5); and adhering said operating element (8) to the inner surface (6) of said outer layer (5).

19. The method according to claim 18, characterised in that said operating element (8) is adhered to the inner surface (6) of said outer layer (5) before said outer layer (5) is removed from said mould surface.

20. The method according to claim 18 or 19, characterised in that it comprises the further step of embedding said operating element (8) between said outer layer (5) and an inner layer (10), which inner layer (10) is adhered to the inner surface (6) of said outer layer (5) after having positioned said operating element (8) against the inner surface (6) of said outer layer (5) and which operating element (8) preferably comprises a sensor element (13) and a light source (14).

Description

[0050] Other advantages and particularities of the present invention will become apparent from the following description of some particular embodiments of the skin and the method for producing it according to the invention. This description is only given by way of example and is not intended to limit the scope of the invention. The reference numerals used in the description relate to the annexed drawings wherein:

[0051] FIG. 1 is a schematic perspective view on a trim part, in particular a dashboard, which contains an elastomeric skin according to an embodiment of the present invention;

[0052] FIG. 2 is an enlarged schematic front view on a portion of the skin at the location of a first operating element, i.e. at the location of a pressure sensitive switch sensor;

[0053] FIG. 3 is a schematic cross-sectional view through the trim part at the location of the pressure sensitive switch sensor;

[0054] FIG. 4 is an enlarged schematic cross-sectional view through the outer layer of the skin at the location of the pressure sensitive switch sensor; and

[0055] FIG. 5 is an enlarged schematic front view on a portion of the skin at the location of a second operating element, i.e. at the location of a sensor element forming a slider.

[0056] The invention generally relates to a skin 1 for a vehicle interior trim part 2 such as a dashboard, a door panel, a console, a lid of a glove compartment, etc. As can be seen in FIG. 3, the trim part comprises the skin 1 which is adhered to a rigid substrate layer 3. The skin 1 can be adhered directly to the substrate layer 3, by means of an adhesive or by means of an overmoulding process wherein the skin 1 is moulded, in a mould, over the substrate layer 3. Preferably, the skin 1 is adhered to the substrate layer 3 through the intermediary of a foam layer 4. This foam layer 4 can be produced by a moulding process in between the skin 1 and the substrate layer 3.

[0057] The skin 1 according to the present invention comprises at least a flexible outer elastomeric layer 5, with an inner surface 6 and an outer surface 7 which forms the visible surface, i.e. the A-surface, of the skin 1. The outer elastomeric layer 5 may be a thermoplastic layer or foil, in particular a TPE (thermoplastic elastomer) layer such as a TPO or a PVC skin. Such thermoplastic skin layers can be moulded by a thermoforming process or for example by a slush moulding process. The elastomeric outer skin layer 5 can also be made starting from a curable composition, in particular a curable polyurethane composition. This curable composition is a flowable material which is applied onto a mould surface and which is allowed to cure on that mould surface to produce the outer elastomeric skin layer 5.

[0058] The curable composition can either be applied by a spray process against the surface of an open mould or it can be applied in a closed mould, more particularly poured but preferably injected in accordance with a reaction injection moulding (RIM) process. Use can be made of a light-stable coloured PU reaction mixture. Reference can be made to EP-B-0 303 305, EP-B-0 379 246, WO 98/14492, EP-B-0 929 586 and WO 04/000905, which are included herein by reference.

[0059] In a variant embodiment, a finishing layer, in particular a light-stable paint or a so-called in-mould coating, either water or solvent-based, can be applied as a first coating layer against the mould surface. This paint composes together with the elastomeric layer subsequently applied thereto, the outer elastomeric skin layer 5.

[0060] The outer skin layer 5 is elastomeric which means that it has generally an elongation, measured in accordance with DIN/EN/ISO 527-3, of at least 30%, preferably of at least 50%. Its flexural modulus, measured in accordance with ASTM D790-03, is preferably smaller than 100 MPa, more preferably smaller than 75 MPa and most preferably lower than 55 MPa or even lower than 40 MPa. Generally, its overall density is larger than 300 kg/m.sup.3, preferably larger than 500 kg/m.sup.3 and more preferably larger than 600 kg/m.sup.3.

[0061] In contrast to the outer skin layer 5, the substrate layer 3 is relatively rigid and has in particular a flexural modulus, measured according to ASTM D790, higher than 500 MPa, preferably higher than 700 MPa. Although the substrate layer can be made of a thermosetting material, the substrate is preferably made of a thermoplastic material. This thermoplastic material is preferably selected from the group consisting of PC (polycarbonate), ABS (acrylonitrile butadiene styrene) and ABS blends, in particular PC/ABS, SMA (styrene maleic anhydride), PPO (polyphenylene oxide), TPO (thermoplastic olefin), in particular PP (polypropylene), polyacetals, in particular POMs (polyoxymethylenes), nylon, polyester, acrylic and polysulfone.

[0062] The outer elastomeric skin layer 5 may also be produced in two or more layers which are each produced from a curable composition, as described in WO 2007/137623.

[0063] The skin 1 according to the present invention comprises moreover at least one operating element 8 which has an operating surface 9 and which is adhered to the inner surface 6 of the outer elastomeric layer 5. In the present text and claims, the term operating element indicates an element which is configured to be connected to an electric or electronic component to enable a user to control the operation of this component.

[0064] To adhere the operating element 8 to the outer layer 5, the operating element 8 can be adhered thereto by means of an adhesive or it can be applied thereto during the production of the outer layer, when the material of the outer layer 5 has not yet completely cured. It is also possible to apply the operating element 8 onto the substrate layer 3 and to overmould the operating element 8 together with the substrate layer 3 with the liquid material used to produce the outer layer 5.

[0065] In the embodiment illustrated in FIG. 3, the operating element 8 is adhered to the outer elastomeric layer 5 by means of an inner elastomeric layer 10 which is produced against the inner surface of the outer elastomeric layer 5. The inner elastomeric layer 5 may have a same composition and may be produced in a same way as described hereabove for the outer elastomeric layer 5. In particular, both layers 5 and 10 can be produced as disclosed in WO 2007/137623. The outer elastomeric layer 5 is preferably produced by applying a first curable polyurethane composition onto the mould surface and the inner elastomeric layer 10 by applying a second curable polyurethane composition onto the back of the outer elastomeric layer 5. The first curable polyurethane composition is preferably an aliphatic polyurethane composition whereas the second curable polyurethane composition is preferably an aromatic polyurethane composition.

[0066] The trim part 2 illustrated in FIG. 1 is a dashboard. The dashboard 2 comprises an elastomeric skin 1 which comprises openings to integrate functional elements such as an instrument panel in the skin 1. The skin 1 comprises also an area wherein operating elements 8 are integrated on the back side of the skin so that they are hidden from view. These operating elements 8 may be provided on an electronic printed foil 15 having a tail which sticks out of the trim part 2 so that the operating elements 8 can be connected to a controller.

[0067] To avoid deformations in the area of integration when the product is exposed to different environment temperatures, the integrated printed foil has preferably a shrinkage factor similar to the elastomeric skin and/or the E-modulus (Young's modulus) should be the same or smaller than the E-modulus of the elastomeric layer. A printed foil of TPU material is very appropriate to be used in combination with elastomeric materials.

[0068] The electronic printed foil can already be foreseen of electronic surface mounted devices, like LEDs, haptic actuators, an electric coil for contactless charging, an RFID reader, an antenna, etc. The printed foil can be as well an OLED display.

[0069] A first operating element 8A may be intended to switch on the lighting behind other hidden operating elements so that they become visible. It comprises an on/off switch formed by a pressure sensor 13 which has an operating surface 9. The first operating element 8A also comprises a light source 14 with two opposite LEDs 14A and 14B. The space between the LEDs is filled with a light guiding material which diffuses the light of the LEDs in different directions to create a uniform lighting of the first area 11. The light source 14 can additionally be covered completely or partially by a light filter which filters out certain wavelengths, e.g. to show a coloured image. Such light filters also form part of the light source 14 as they determine the wavelengths of the light which is supplied by the light source 14 to the inner surface 6 of the outer elastomeric layer 5. The LEDs 14A and 14B are energized upon initial actuation of the pressure sensor 13 to have a visual indication of the actuation of the operating element 8A and to have a clearer view on the location of the first operating element 8A. Also the light sources of other hidden operating elements 8 may be energized upon actuation of the first operating element 8A so that they become visible to the user.

[0070] To indicate the location of the first operating element 8A when its light source 14 is not energized, the operating surface 9 of the first operating element 8A is located in a first area 11 of the visible surface of the skin 1 which is surrounded by a second area 12 of this visible surface. At least a portion of the first area 11 has a first surface texture which is different from the surface texture of the second area 12, i.e. from the second surface texture.

[0071] Usually, the second surface texture is present over the main part of the surface of the skin. This second surface texture may for example be a leather texture or any other texture that is used for trim parts. Such a leather texture has been illustrated on a larger microscopic scale in FIG. 4. It has quite deep valleys and quite high peaks and the surface forming the peaks and the valleys is also quite rough. The Ra value (roughness value), measured as defined in DIN EN ISO 4287:1998 (the arithmetical mean deviation of the assessed texture profile), comprises for example for the illustrated texture profile 54 μm whilst the Pt value, i.e. the total height of the profile measured as defined in DIN EN ISO 4287:1998 (the sum of the height of the largest profile peak and the largest profile valley depth within the evaluation length), comprises for example about 220 μm. The root mean square slope value, in particular the delta q value Rdq as determined in accordance with DIN EN ISO 4287:1998, is for example equal to about 1.27. The larger the delta q value, the steeper the slopes of the profile and the more diffuse reflection of the light, and thus the matter the surface. A higher roughness also causes a matter surface. Due to these parameter values of the second surface texture, and the reflection coefficient of the polyurethane material from which the skin is made (by a spray process against a textured mould surface), the gloss value of the skin 1 described hereabove and illustrated in FIG. 4 comprises about 0.2 gloss units in the second area 12 thereof.

[0072] As illustrated in FIG. 4, the first surface texture is preferably smoother than the second surface texture. In this way, the surface of the first skin area 11 has a higher gloss than the surface of the second skin area 12. This means that the specular light reflection is higher and the diffuse light reflection is lower in the first skin area 11 than in the second skin area 12. This assists in making the first skin area 11 visible within or next to the second skin area 12. The difference in gloss between the first and the second skin area can be measured in accordance with ASTM D523-14(2018). Usually this is done under an angle of 60° but, for low gloss values, a different gloss value can be determined more clearly when measuring it under an angle of 85° (which results in higher gloss values).

[0073] The first surface texture may be produced against a completely smooth mould surface, i.e. against a non-textured mould surface which may even be polished. Depending on the skin material, the surface of the skin will be smoother or less smooth. When the skin material is applied in a liquid form against the mould surface, the viscosity thereof may for example have an effect on the smoothness of the resulting skin surface. The obtained gloss of the skin surface depends also on the composition of the skin material. For a polyurethane skin made by spraying a curable polyurethane material against a mould surface, the gloss value may be comprised for example between 3 and 6 gloss units. If a higher gloss is desired, an in-mould coating can first be applied onto the mould surface, for example a lacquer.

[0074] In order to indicate the location of the first operating element even more clearly without illumination, surface relief elements are provided in the first surface area, i.e. at the location of the first operating element 8A. These surface relief elements comprise a central icon 16, indicating the on/off switching function, surrounded by circles of dots 17 which do not only form a clear visual indication but also a clear tactile indication of the location of the first operating element 8A. The dots 17 are in fact similar to the raised-points of braille but they are even larger so that they can also be felt easily by unexperienced users. Within the circular icon 16, the surface of the skin is completely smooth so that the recessed area within the circular icon 16 can be clearly felt to indicate the user where he has to push to actuate the first operating element 8A.

[0075] In the cross-section illustrated in FIGS. 3 and 4, it can be seen that the icon 16 and the dots 17 have a height h, or provide in other words a height difference h, which is of a same order of magnitude than the total profile height Pt of the second surface texture and which is in particular comprised between 0.15 and 0.2 mm. This height difference corresponds to an increased thickness of the outer elastomeric layer 5 at the location of the icon 16 or the dots 17.

[0076] In an alternative embodiment, the icon 16 and/or the dots 17, could be formed by corresponding depressions in the outer surface 7 of the outer skin layer 5, instead of by elevations.

[0077] In the embodiment illustrated in FIGS. 2 to 4, the gloss difference between the first 11 and the second surface area 12 is maximally since not only the skin surface next to the dots 17 and next to the icon 16 is completely smooth but also the surface of the dots 17 and of the icon 16 itself. In an alternative embodiment, the surfaces of the dots 17 and of the icon 16 could be made rougher so that the dots 17 and the icon 16 are matter and are easier to feel. When they have a smooth surface, due to the oblique sides of the dots 17 and the icon 16, they reflect the light in different directions which assists in their visibility.

[0078] FIG. 5 illustrates the surface of the skin 1 at the location of a second operating element 8B. This element 8B comprises an elongated sensor element which enables to detect the position of the user's finger and any sliding movement thereof. Such a slider enables therefore to control for example the volume of the radio, the temperature, the fan speed, opening and closing of the windows, etc. The first surface area has again a smooth surface texture and is provided with dots 18 which have a same shape as the dots illustrated in FIG. 4. More particularly they have a rounded dome-shape so that the user can slide with his finger easily over the first area 11. The dots 18 also have a smooth surface and also in between the dots 18 the first surface area 11 is smooth. The first surface area 11 having an elongated form with a narrowing width, thus forming a sign that by sliding the finger to the narrower side the value of the parameter controlled by the second operating element 8B is reduced, whereas when the user slides his finger to the wider side the value of the parameter controlled by the second operating element 8B is increased.