Interior trim or lining part of a vehicle and method for manufacturing such a part

Abstract

Interior trim or lining part of a vehicle and method of making such a part The present invention relates to an interior trim or lining part of a vehicle comprising a support layer (1), an appearance layer (2), a first comfort layer (3) between the support layer (1) and the appearance layer (2).It further comprises a second comfort layer (3') between the first comfort layer (3) and the support layer (1), the first and second comfort layers each comprising a compressible structure of elongated flexible and / or supple elements (3a, 3'a) and being configured so as to generate, in reaction to a compressive force acting on the two comfort layers, a first reaction force induced by the first comfort layer and a second reaction force induced by the second comfort layer, combining to produce a resultant reaction force substantially aligned with, or substantially parallel to, the compressive force. Figure to be published with the abbreviation: Fig. 2c.

Description

Title of the invention: Interior trim or lining piece for a vehicle and method for manufacturing such a piece

[0001] The present invention relates to the field of vehicle interior equipment, and more particularly to interior trim or lining parts for vehicles, especially land vehicles. It relates to an interior trim or lining part for a vehicle and a method for manufacturing such a part.

[0002] Interior trim or fittings of vehicles, i.e. in the passenger compartment of vehicles, are, for example, dashboards, door panels, center consoles, door or window pillars, and their sub-components (door openings, armrests, strips, medallions...etc).

[0003] Such an interior trim or lining component for a vehicle may comprise a superposition of layers consisting of a support layer, a surface (or covering) layer comprising the visible external surface, and a comfort layer extending between the support layer and the surface layer. The surface layer, generally of the leather or textile type, and the comfort layer form the covering of the component. The comfort layer may optionally include a functional or technical layer.

[0004] Such a component is described, for example, in documents FR3121866 and US6231940. To achieve improved comfort, the comfort layer of such a component is compressible and, for this purpose, comprises a 3D compressible structure, such as a 3D mesh textile or a knitted fabric known as "3D Rashel". Such a compressible structure consists of a material composed of a multitude of flexible yarns (made of polyester, polypropylene, or polyamide) placed side by side and oriented in a direction substantially perpendicular or transverse to the median plane of the comfort layer.

[0005] When a user (passenger or driver of the vehicle) touches the part, they can exert a compressive force (stress) on the surface of the part's surface layer (or coating), particularly with one of their fingers, in a given direction, generally a direction substantially normal to said surface, thus compressing the material (compressible structure) of the comfort layer. In response to this compressive stress, the comfort layer generates a reaction force in a given direction, characterizing a haptic response (a sensation of resistance felt by the user). In the absence of stress, the comfort layer returns to its initial shape due to the elastic energy accumulated by the compressible structure during the stress.

[0006] However, due to the particular configuration of the flexible wires in the compressible structure, which gives it anisotropic behavior, the haptic response (force of reaction to stimulation) perceived / felt by the user exhibits an angular shift; that is, the haptic response (direction of the reaction force) is not aligned with, or parallel to, the direction of the compression force. This problem of alignment or parallelism of the haptic response gives the user a sensation of a particular orientation of their finger due to a shift in the response angle. This unpleasant shift effect felt by users is contrary to the quality sought by current users.

[0007] The present invention aims to overcome these drawbacks.

[0008] The present invention relates to an interior trim or lining part for a vehicle, said part having a visible external surface and comprising a support layer, an appearance layer comprising the visible external surface and a first comfort layer extending between the support layer and the appearance layer, characterized in that it further comprises a second comfort layer extending between the first comfort layer and the support layer, the first and second comfort layers:

[0009] - each comprising a compressible structure of flexible elongated elements and / or flexible materials, such as, for example, threads, fibers, or filaments, oriented in a transverse direction or substantially perpendicular to the respective median plane of the first or second comfort layer,

[0010] - and being configured so as to generate, in reaction to a compressive force by applying pressure to the two comfort layers in a given direction, a first reaction force induced by the first comfort layer and a second reaction force induced by the second comfort layer combine to produce a resultant reaction force, characterizing a haptic response, the direction of which is substantially aligned with, or parallel to, the direction of the compression force.

[0011] The present invention also relates to a method for making an interior trim or lining piece, said method consisting of providing a support layer, an appearance layer comprising the visible external surface of said piece and a first comfort layer by placing the latter between the support layer and the appearance layer, characterized in that it further consists of providing a second comfort layer by placing it between the first comfort layer and the support layer, the first and second comfort layers:

[0012] - each comprising a compressible structure of flexible elongated elements and flexible materials, such as, for example, threads, fibers, or filaments, oriented in a transverse direction or substantially perpendicular to the respective median plane of the first or second comfort layer,

[0013] - being configured so as to generate, in reaction to such a compressive force by applying pressure to the two comfort layers in a given direction, a first reaction force induced by the first comfort layer and a second reaction force induced by the second comfort layer combine to produce a resultant reaction force, characterizing a haptic response, the direction of which is substantially aligned with, or substantially parallel to, the direction of the compression force.

[0014] The invention will be better understood from the following description, which relates to a preferred embodiment, given by way of non-limiting example, and explained with reference to the accompanying schematic drawings, in which:

[0015] [Fig. la],

[0016] [Fig.lb]et

[0017] [Fig. 1e] represent steps showing the reaction of a prior art vehicle interior trim or lining part to a compressive force stressing the comfort layer, with a cross-sectional view of the part,

[0018] [Fig.2a],

[0019] [Fig.2b] and

[0020] [Fig.2c] represent steps showing the reaction of a housing part or vehicle interior trim, according to the present invention, to a compressive force acting on the two comfort layers, with a cross-sectional view of the part and a reaction force direction graph,

[0021] [Fig. 3] shows the part of Figure 2, in an embodiment where the layer of surface contains portions of stitching lines.

[0022] Figures 1a, 1b, and 1e show a prior art interior trim or lining piece intended for installation in a vehicle, particularly a land vehicle. The interior trim or lining piece has a visible external surface and comprises a superposition of layers consisting of a support layer 1, an appearance layer 2 comprising the visible external surface (at least from inside the vehicle), and a comfort layer 3 extending between the support layer 1 and the appearance layer 2. The appearance layer 2 and the comfort layer 3 form the covering of the piece. The comfort layer 3 comprises a compressible structure of elongated, flexible elements 3a, such as, for example, yarns, fibers, or filaments, oriented in a transverse direction or substantially perpendicular to the respective median plane of the comfort layer.These elongated elements 3 are capable of elastically deforming in response to a compressive force and of returning to their initial shape in the absence of such a compressive force.

[0023] Figures 1a, 1b and 1e represent more particularly steps showing the reaction of such a prior art part to such a compressive force exerted on The room is activated by applying pressure to comfort layer 3. The room thus transitions from an initial unactivated state ([Fig. 1a]) to an activated state when a user's finger U presses on the outer surface of aspect layer 2 ([Fig. 1b]), exerting a compressive force that compresses comfort layer 3 ([Fig. 1e]). Fig. 1e shows that comfort layer 3 generates, in response to the compressive force, a reaction force induced by the deformation of comfort layer 3, characterizing a haptic response. The direction H of the reaction force (or haptic response) is angularly shifted, being inclined relative to the direction D of the compressive force ([Fig. 1e]). This results in a particular sensation or discomfort for the user (the sensation felt by the touch of their finger U).

[0024] The attached figures 2 to 3 show a vehicle interior trim or lining piece according to the present invention, making it possible to improve this bad feeling or feeling of discomfort felt / perceived by a user with a prior art part such as that schematically illustrated in figure 1.

[0025] The part according to the present invention has a visible external surface and comprises a support layer 1, an appearance layer 2 having the visible external surface (at least from inside the vehicle) and a first comfort layer 3 extending between the support layer 1 and the appearance layer 2.

[0026] In accordance with the present invention, as can also be seen in the accompanying Figures 2 to 3, the part further comprises a second comfort layer 3' extending between the first comfort layer 3 and the support layer 1. The first and second comfort layers 3, 3' each comprise a compressible structure of flexible and supple elongated elements 3a, 3'a, such as, for example, threads, fibers, or filaments, oriented in a transverse direction or substantially perpendicular to the respective median plane P, P' of the first or second comfort layer 3, 3'. These elongated elements 3a, 3'a are capable of elastically deforming in response to a compressive force and of returning to their original shape in the absence of such a compressive force.

[0027] Each comfort layer 3, 3' can be, for example, a layer of 3D mesh material, such as a knitted textile of the Raschel 3D type, preferably with a thickness of 5 to 30 mm, more preferably 10 to 20 mm, and a basis weight of between 100 and 1500 g / m², more preferably between 600 and 900 g / m². The superposition of the two layers thus makes it possible to obtain a significant comfort thickness of the order of 30 to 60 mm, which allows the user to exert pressure in the room without the sensation of contacting a hard part such as that of the support layer.

[0028] The first and second comfort layers 3, 3' may include:

[0029] - two outer layers (not shown). These two layers can be composed of knitted stitches independent of each other, for example made of synthetic filaments (such as polyester or nylon).

[0030] - the compressible structure connecting, by the ends of the elongated elements, the two outer layers. The structure thus forms an intermediate layer between the two outer (or surface) layers.

[0031] The aspect layer 2 can be, for example, a skin, a textile, a film, a non-woven or a textile material.

[0032] The support layer 1 may form part of a support / substrate for the part. The support layer 1 may extend parallel to the appearance and comfort layers 2, 3, 3'. The support / substrate may include lateral portions 1' (or peripheral edges) extending perpendicularly to the support layer 1 (Figures 2a, 2b, 2c, 3). These lateral portions 1' serve, in particular, to form a receptacle, a "box," for receiving the stacking of the appearance layers 2 and comfort layers 2, 3, 3', especially the comfort layers 3, 3'.

[0033] Furthermore, still in accordance with the present invention, the first and second comfort layers 3, 3' are configured so as to generate, in reaction to a compression force acting on the two layers 3,3' (first and second layers 3, 3'), a first reaction force induced by the first comfort layer 3 and a second reaction force induced by the second comfort layer 3 combining to produce a resultant reaction force, characterizing a haptic response, the direction H of which is substantially aligned with, or parallel to, the direction of the compression force.

[0034] It results from such alignment or parallelism of the resulting reaction force that the haptic response is perceived by the user as being in a direction H substantially aligned or parallel to the direction D of the compression force, which translates for the user into a better feeling and better comfort, more qualitative, than with a prior art piece such as that shown in Figure 1.

[0035] The first reaction force is oriented in a direction HL. The second reaction force is oriented in a direction H2. The resulting reaction force, characterizing the haptic response, is oriented in a direction H.

[0036] In a preferred embodiment, as can be seen in Figures 2a, 2b, and 2c, the first and second reaction forces are oriented respectively in two directions H1, H2 inclined at substantially the same angle, in symmetrical opposition with respect to the direction D of the compression force. The two directions thus make a substantially identical angle with direction D but are in opposite directions to each other. Such a feature makes it possible to create two inverted haptic responses produced respectively by the two comfort layers 3, 3'. This Inverted haptic response allows us to obtain a direction H of the resulting reaction force substantially aligned with the direction D of the compression force.

[0037] Figures 2a, 2b, and 2c more particularly illustrate steps showing the reaction of such a part according to the present invention to such a compressive force exerted on the part by stressing the two comfort layers 3, 3'. The part thus transitions from an initial unstressed standby configuration ([Fig. 2a]) to a stressed configuration when a user's finger U presses on the outer surface of the appearance layer 2 ([Fig. 2b]), exerting a compressive force (stress) that stresses (in compression) the two comfort layers 3, 3' ([Fig. 2c]). The direction of the compressive force illustrated in Figures 2b and 2c is normal / orthogonal to the surface of the appearance layer 2 or to the median planes P, P'. In reaction to the compression force, the first comfort layer 3 generates the first reaction force whose direction H1 is inclined with respect to the direction D of the compression force ([Fig.the]) and the second comfort layer 3 generates the second reaction force, the direction of which H2 is inclined at approximately the same angle, in symmetrical opposition to the direction D of the compression force ([Fig. 1e]). The combination of the two reaction forces in the directions H1 and H2 (visible in the graph shown in [Fig. 2c] next to the part) results in the user's haptic sensation being perceived or felt in a direction H that is substantially aligned with, or substantially parallel to, that (D) of the compression force acting on the two comfort layers 3 and 3'. This allows the user to have a more pleasant and higher-quality sensation.Furthermore, as previously stated, the thickness of comfort material created by the superposition of the two comfort layers 3, 3' allows the user to touch the room's covering by compressing it without feeling like they are contacting a hard part such as the support layer 1 or a part 1' of the support / substrate.

[0038] In a particular embodiment, as can be seen in Figures 2a, 2b, 2c and 3, the elongated elements 3a, 3'a of the first and second comfort layers 3, 3' may include at least one non-straight portion with a curvature oriented in a given direction. It is understood that the curvature may extend along the entire length of the elongated element 3a, 3'a or only a significant portion proportional to its total length. It is also understood that at least a majority of, preferably all, the elongated elements 3a, 3'a of each of the two comfort layers 3, 3' have this characteristic in order to achieve the effect of alignment or parallelism of the direction H of the reaction force / haptic response with respect to the direction D of the compressive force (stress).

[0039] Preferably, in this embodiment, the curvature of the non-straight portion of the elongated flexible elements 3a of the first comfort layer 3 and The curvature of the, or at least one of the, non-straight portion(s) of the elongated elements 3'a of the second comfort layer 3' can be oriented in opposite directions. This embodiment allows for a haptic response whose direction H is substantially aligned with the direction of the compression force.

[0040] It should be noted that if the curvature of the non-straight portion of the elongated flexible elements of the first comfort layer 3 and the curvature of the non-straight portion of the elongated elements of the second comfort layer 3' were oriented in the same direction, the haptic response of each comfort layer 3, 3', when both layers 3, 3' are applied, would be the same, and the haptic response would then be inclined with respect to the direction D of the compression force, which would not fully meet the quality objective of the invention. However, such a superposition of the two comfort layers would still improve comfort by allowing a user to touch the piece under compression without contacting or feeling contact, in particular, with the support layer 1.

[0041] According to a feature of the invention, at least one of the three layers, among the appearance layer 2 and the two comfort layers 3, 3', is fixed, for example by means of a bonding agent such as an adhesive or glue, or is hot-bonded or laminated, with at least one of the other two layers or with the support layer 1 and / or a part 1' of the substrate / support.

[0042] It is understood that the comfort layer 3, 3' concerned is fixed with at least one of the two other appearance or comfort layers 3, 3' or with the support layer 1 and / or a part 1' of the substrate / support, by its external part, that is to say by at least one of its two external layers.

[0043] According to another feature of the invention, the appearance layer 2 can be hot-bonded by fusion or laminated with the first comfort layer 3 or with both comfort layers 3, 3'.

[0044] According to another feature of the invention, the two comfort layers 3, 3' can be fixed to the support layer 1 and / or a part 1' of the support / substrate comprising the support layer 1.

[0045] Preferably, the appearance layer 2 and the two comfort layers 3, 3' can be bonded together by means of an adhesive layer, or by means of an adhesive sprayed or deposited between the layers. In a particular configuration, the two comfort layers 3, 3' can be assembled with the support layer 1 or a portion 1' of the substrate / support, and then the appearance layer 2 can be assembled with the two comfort layers 3, 3'.

[0046] In a particular embodiment, as can be seen in [Fig. 3], the piece may locally include at least one line of stitching 4, and / or at least one portion of topstitching, passing through, by joining them together, with the effect of to form indentations, hollows and / or reliefs / bumps on the visible external surface:

[0047] - i.e. the appearance layer 2 and the first comfort layer 3 ([Fig.3]),

[0048] - or, in one variant, the appearance layer 2 and the second comfort layer 3' (not illustrated),

[0049] - or, in another variant, the aspect layer 2 and a technical reverse extending between the second comfort layer 3' and the support layer (not shown).

[0050] Such lines of stitching and / or portions of topstitching create indentations or local deformations in the piece resulting in a configuration of hollows and bumps giving a "quilted" or "padded" effect / appearance to the piece.

[0051] The part may also include, optionally, a functional layer or a layer with a technical purpose.

[0052] The present invention also relates to a method for manufacturing such an interior trim or lining part for a vehicle. It consists of providing a support layer 1, an appearance layer 2 comprising the visible external surface of said part, and a first comfort layer 3, the latter being placed between the support layer 1 and the appearance layer 2.

[0053] According to the present invention, such a method further consists of providing a second comfort layer 3 by placing it between the first comfort layer 3 and the support layer 1.

[0054] In such a process, the first and second comfort layers 3, 3' are such as those described above, that is to say that they:

[0055] - each comprise a compressible structure of elongated elements 3a, 3'a flexible and supple, such as for example threads, fibers or filaments, oriented in a transverse direction or substantially perpendicular to the median plane P, P' respective of the first or second comfort layer 3, 3' and capable of elastically deforming in reaction to a compression force and of returning to their original shape in the absence of such a compression force,

[0056] - are configured so as to generate, in reaction to such a compressive force soliciting the two comfort layers 3, 3' in a given direction D, a first reaction force induced by the first comfort layer 3 and a second reaction force induced by the second comfort layer 3 combine to produce a resultant reaction force, characterizing a haptic response, whose direction H is substantially aligned with, or substantially parallel to, the direction D of the compression force.

[0057] Preferably, the first and second reaction forces are oriented respectively in two directions H1, H2 inclined substantially with the same angle, in symmetrical opposition with respect to the direction D of the compression force.

[0058] Preferably, the elongated elements 3a, 3'a of the first and second comfort layers 3, 3' comprise at least one non-straight portion with a curvature oriented in a given direction (Figures 2a, 2b, 2c, 3).

[0059] Preferably, such a method may consist of arranging the first and second comfort layers 3, 3' relative to each other so that the curvature of the non-straight portion of the elongated elements 3a of the first comfort layer 3 and the curvature of the or at least one of the non-straight portion(s) of the elongated elements 3'a of the second comfort layer (3') are oriented in opposite directions (Figures 2a, 2b, 2c, 3).

[0060] Preferably, such a process may consist of fixing, for example by means of a bonding agent such as an adhesive or glue, or of hot-fusing or laminating at least one of the three layers, among the appearance layer 2 and the two comfort layers 3, 3', with at least one of the other two layers or with the support 1 and / or a part 1' of the substrate / support.

[0061] According to one feature of the invention, the process may consist of hot-bonding or laminating the appearance layer 2 with the first comfort layer 3 or with the two comfort layers 3, 3'.

[0062] According to one feature of the invention, the method may consist of fixing the two comfort layers 3, 3' on the support layer 1 and / or a part 1' of the support / substrate comprising the support layer 1.

[0063] Preferably, the process can consist of gluing together the appearance layer 2 and the two comfort layers 3, 3', by means of an adhesive layer, or of a glue sprayed or deposited between the layers.

[0064] In a particular form, the process may consist of assembling the two comfort layers 3, 3' with the support layer 1 or a part 1' of the substrate / support, and then assembling the appearance layer 2 with the two comfort layers 3, 3'.

[0065] In a particular embodiment, the process may consist of making at least one line of stitching 4, and / or at least one portion of topstitching, passing through, by joining them together, with the effect of forming indentations, hollows and / or reliefs / bumps on the visible external surface, either the appearance layer 2 and the first comfort layer 3, or the appearance layer 2 and the second comfort layer 3, or the appearance layer 2 and a technical reverse extending between the second comfort layer 3 and the support layer 1.

[0066] Such a technical backing can be a textile, for example a PET or PP non-woven fabric, or a mixture of these materials. It can serve as a backing surface for the stitching points forming the seam line(s) 4 and / or for the topstitching.

[0067] Thus, such a part or such a method for making such a part allows the user (passenger or driver of the vehicle):

[0068] - a superior user experience, precisely meeting the current user requirements, thanks to achieving a more pleasant and higher quality tactile feel of the part,

[0069] - to touch the coating of the part by compressing it without having the sensation of contact a hard part such as support layer 1 or part 1' of the support / substrate.

[0070] Of course, the invention is not limited to the embodiment described and shown in the accompanying drawings. Modifications remain possible, particularly with regard to the composition of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Demands

1. A vehicle interior trim or lining component, said component having a visible external surface and comprising a support layer (1), an appearance layer (2) having the visible external surface, a first comfort layer (3) extending between the support layer (1) and the appearance layer (2), characterized in that it further comprises a second comfort layer (3') extending between the first comfort layer (3) and the support layer (1), the first and second comfort layers (3, 3') - each comprising a compressible structure of elongated flexible and / or supple elements (3a, 3'a) oriented in a direction transverse or substantially perpendicular to the respective median plane (P, P') of the first or second comfort layer (3, 3'), - and being configured so as to generate, in reaction to such a compressive force acting on the two comfort layers (3, 3') in a given direction (D),a first reaction force induced by the first comfort layer (3) and a second reaction force induced by the second comfort layer (3) combining to produce a resultant reaction force, characterizing a haptic response, whose direction (H) is substantially aligned with, or substantially parallel to, the direction (D) of the compression force.

2. Interior trim or lining piece according to claim 1, characterized in that the first and second reaction forces are oriented respectively in two directions (H1, H2) inclined substantially with the same angle, in symmetrical opposition with respect to the direction (D) of the compression force.

3. Interior trim or lining piece according to claim 1 or 2, characterized in that the elongated elements (3a, 3'a) of the first and second comfort layers (3, 3') comprise at least one non-straight portion with a curvature oriented in a given direction.

4. Interior trim or lining piece according to claim 3, characterized in that the curvature of the non-straight portion of the elongated elements (3a) of the first comfort layer (3) and the curvature of the or at least one of the non-straight portion(s) of the elongated elements (3'a) of the second comfort layer (3') are oriented in opposite directions.

5. Interior trim or lining piece according to any one of claims 1 to 4, characterized in that at least one of the three layers, among the appearance layer (2) and the two comfort layers (3, 3'), is fixed, for example by means of a bonding agent such as an adhesive or glue, or is hot-bonded or laminated, with at least one of the other two layers or with the backing layer (1) and / or a part (1') of a backing / substrate comprising the backing layer (1).

6. Interior trim or lining piece according to any one of claims 1 to 5, characterized in that it comprises, locally, at least one line of stitching (4), and / or at least one portion of topstitching, passing through, by joining them together, with the effect of forming indentations, hollows and / or reliefs / bumps on the visible external surface, either the appearance layer (2) and the first comfort layer (3), or the appearance layer (2) and the second comfort layer (3'), or the appearance layer (2) and a technical reverse extending between the second comfort layer (3') and the support layer (1).

7. A method for manufacturing an interior trim or lining component for a vehicle, said method comprising a support layer (1), a surface layer (2) comprising the visible external surface of said component, and a first comfort layer (3) by placing the latter between the support layer (1) and the surface layer (2), characterized in that it further comprises a second comfort layer (3) by placing it between the first comfort layer (3) and the support layer (1), the first and second comfort layers (3, 3'): - each comprising a compressible structure of elongated, flexible, and supple elements (3a, 3'a) oriented in a direction transverse or substantially perpendicular to the respective median plane (P, P') of the first or second comfort layer (3, 3'), - being configured so as to generate, in reaction to such a compressive force acting on the two layers comfort (3, 3') in a given direction (D), a first reaction force induced by the first comfort layer (3) and a second reaction force induced by the second comfort layer (3) combine to produce a resultant reaction force, characterizing a haptic response, whose direction (H) is substantially aligned with, or substantially parallel to, the direction (D) of the compression force.

8. Method of making an interior trim or lining part according to claim 7, characterized in that the first and second reaction forces are oriented respectively in two directions (H1, H2) inclined substantially with the same angle, in symmetrical opposition with respect to the direction (D) of the compression force.

9. Method of making an interior trim or lining part according to claim 7 or 8, characterized in that the elongated elements (3a, 3'a) of the first and second comfort layers (3, 3') comprise at least one non-straight portion with a curvature oriented in a given direction.

10. Method of making an interior trim or lining part, according to claim 9, characterized in that it consists of arranging the first and second comfort layers (3, 3') relative to each other so that the curvature of the non-straight portion of the elongated elements (3a) of the first comfort layer (3) and the curvature of the or at least one of the non-straight portion(s) of the elongated elements (3'a) of the second comfort layer (3') are oriented in opposite directions.

11. Method of making an interior trim or lining part according to any one of claims 7 to 10, characterized in that it consists of fixing, for example by means of a bonding agent such as an adhesive or glue, or of hot-bonding or laminating at least one of the three layers, among the appearance layer (2) and the two comfort layers (3, 3'), with at least one of the other two layers or with the support layer (1) and / or a part (1') of the support / substrate comprising the support layer (1).

12. A method for manufacturing an interior trim or lining part, according to any one of claims 7 to 11, characterized in that it consists of making at least one line of stitching (4), and / or at least one portion of topstitching, passing through, by joining them together, with the effect of forming indentations, hollows and / or reliefs / bumps on the visible external surface, either the appearance layer (2) and the first comfort layer (3), or the appearance layer (2) and the second comfort layer (3), or the appearance layer (2) and a technical reverse extending between the second comfort layer (3) and the support layer (1).