FR3117073A1 - Trim element comprising a functional element made of pyrolyzed composite material - Google Patents

Abstract

Trim element comprising a functional element made of pyrolyzed composite material The packing element (1) comprises at least one support layer (2) comprising an inner face (8) and an outer face (10), and at least one functional element (6) extending over the support layer (2), said functional element (6) being electrically connected to a current source to perform a function of interaction with a passenger of the vehicle on at least part of an outer surface (14) of the trim element. The functional element (6) comprises at least one layer of material (5) made of a composite material comprising natural fibers in a pyrolyzed polypropylene matrix. Figure for abstract: 1

Description

Trim element comprising a functional element made of pyrolyzed composite material

The present invention relates to a packing element of the type comprising at least one support layer comprising an inner face and an outer face, and at least one functional element extending over the support layer, said functional element being electrically connected to a source current to perform a function of interaction with a vehicle passenger on at least a portion of an outer surface of the trim element.

The invention also relates to a method for producing such a packing element.

The invention applies for example to a trim element forming a door panel, a central console covering or a vehicle dashboard or other.

It is known to integrate particular functionalities intended for the passengers of a vehicle on the external surface of such a trim element in order to improve the comfort offered to the passengers by the trim element. For this purpose, the outer surface of the trim element comprises for example a heated zone, a touch surface for controlling a function of the vehicle, a detection zone for detecting contact with the outer surface and/or other functionalities. Such functionalities are for example created by providing electrical circuits in the trim element, for example under a decorative layer so that the electrical circuits are invisible from outside the trim element.

Such an electric circuit is for example formed by tracks made of carbon material or by copper cables bonded to the support layer. However, such materials are expensive and the process for integrating the electrical circuit in the trim element makes the process for producing the trim element more complex and difficult to implement. Furthermore, if a functional element is badly positioned on the support layer, for example with respect to the decorative layer, the quality of the filling element is degraded because the corresponding functional zone does not extend to the place desired, which can be indicated by a visual indication to inform a passenger of the presence of a functional area.

One of the aims of the invention is to overcome these drawbacks by proposing a trim element comprising at least one functional zone that is simple to produce reliably.

To this end, the invention relates to a packing element of the aforementioned type, in which the functional element comprises at least one layer of material made of a composite material comprising natural fibers in a pyrolyzed polypropylene matrix.

By making the functional element from a composite material comprising natural fibers in a pyrolyzed polypropylene matrix, also known by the terms "pyrolyzed NFPP", the costs of the functional element and therefore of the packing element are reduced, in particular because the functional element can be obtained by recycling a composite material comprising natural fibers in a polypropylene matrix used to produce other parts of the vehicle, for example to produce the support layer of the trim element. Furthermore, the functional element can be easily positioned by making the functional element in a layer of pyrolyzed NFPP applied over a large area of the support layer. In addition, when several functional elements are provided, they can all be made in the same layer of pyrolyzed NFPP, which reduces the number of operations necessary for the production of the packing element and simplifies the positioning of these different functional elements. on the backing layer.

According to other characteristics of the packing element according to the invention, taken in isolation or according to any technically possible combination:

- the layer of material of the functional element defines at least one electrical circuit formed by a pattern extending through the thickness of said layer of material, said pattern comprising at least one conductive zone made of a composite material comprising fibers natural materials in a pyrolyzed polypropylene matrix and at least one non-conductive zone formed by a through opening in said layer of material, said conductive layer being electrically connected to a current source;

- the functional element further comprises a pair of electrodes in contact with the layer of material, said electrodes being electrically connected to a current source for passing an electric current in the layer of material between said electrodes;

- the functional element extends over the external face of the support layer between the support layer and a decorative layer extending opposite the external face of the support layer and forming the external surface of the element filling;

- the support layer is made of a composite material comprising natural fibers in a polypropylene matrix;

- the layer of material is applied to the support layer with a protective film of plastic material, in particular polypropylene;

- the composite material comprising natural fibers in a pyrolyzed polypropylene matrix is obtained by pyrolyzing residues and/or waste of a composite material comprising natural fibers in a polypropylene matrix;

- the proportion of carbon in the composite material comprising natural fibers in a pyrolyzed polypropylene matrix forming the layer of material is greater than 60%; And

- the functional element is a resistive element arranged to heat at least part of the external surface of the packing element when the functional element is powered by a current source.

According to another aspect, the invention relates to a process for producing a packing element as described above, comprising the following steps:

- pyrolyzing a composite material comprising natural fibers in a polypropylene matrix to form a layer of material,

- apply the material layer on a support layer,

- form a functional element in the layer of material, and

- electrically connect the functional element to a power source.

According to another characteristic of the method according to the invention, the layer of material is cut by laser attack, chemical attack, milling or mechanical drilling in the composite material comprising natural fibers in a pyrolyzed polypropylene matrix to form an electrical circuit in the layer of material.

Other aspects and advantages of the invention will appear on reading the following description, given by way of example and made with reference to the appended drawings, in which:

- there is a schematic sectional representation of part of a packing element according to one embodiment of the invention,

- there is a schematic representation of a pattern arranged to form a resistive heating circuit, and

- there is a cross-sectional schematic representation of part of a packing element according to another embodiment of the invention.

With reference to the , a vehicle trim element 1 is described comprising at least one support layer 2, a decorative layer 4 and a functional element 6. Such a trim element is for example intended to form a door panel, a floor covering dashboard or center console or other.

The support layer 2 is arranged to impart its shape and its mechanical characteristics to the packing element 1, in particular its rigidity. The support layer 2 is thus for example made of a substantially rigid material for a door panel, such as a plastic or composite material. According to one embodiment, the support layer 2 is made of a composite material comprising natural fibers in a polypropylene matrix, also known under the name of NFPP for “Natural Fiber PolyPropylene”. The natural fibers are for example chosen from flax, hemp, kenaf and/or wood. The support layer 2 is for example formed by thermocompression in a pressing tool and the support layer 2 is then cut to obtain the desired contour, the shape and contour of the support layer 2 substantially corresponding to the shape of the packing element. Thus, the support layer 2 has for example a three-dimensional shape with zones in relief. By way of example, the support layer 2 can for example comprise a zone protruding from the rest of the support layer 2 to form an armrest.

As a variant, the support layer 2 is produced by injection of plastic material, such as polypropylene (PP), acrylonitrile butadiene styrene polycarbonate (PC ABS), or the like, into a molding cavity having the desired shape. According to another variant, the support layer 2 is obtained by additive manufacturing in the desired shape.

The support layer 2 comprises an internal face 8, intended to extend from the side of the part of the vehicle on which the trim element is to be installed, such as the door of the vehicle in the case of a door panel, and an outer face 10, opposite to the inner face 8, and intended to face the passenger compartment of the vehicle.

The decorative layer 4 extends from the side of the outer face 10 of the support layer 2 over at least a part of the latter. The decorative layer 4 is arranged to impart its appearance and feel to the trim element 1. The decorative layer 4 is thus for example made of a flexible or rigid material, having a particular appearance and/or feel that the 'one wishes to give the trim element 1. Thus, the decorative layer 4 is for example made of textile material, plastic material, ligneous material, leather or imitation leather or other. The decorative layer 4 is shaped to the external face 10 of the support layer 2, that is to say that it substantially matches the shape of the external face 10 in the zone of the support layer 2 that it covers. According to one embodiment, the decorative layer 4 covers the entire support layer 2.

The decorative layer 4 comprises an internal face 12 extending facing the external face 10 of the support layer 2 and an external face 14 extending towards the outside of the trim element 1 and forming the external surface of the trim element 1, that is to say forming the visible part of the trim element 1 from the passenger compartment of the vehicle. The outer face 14 may include decorative patterns or indications intended for a user to indicate to him the presence of a functional zone for example, as will be described later. As a variant or in addition, the decorative layer 4 can be translucent, at least in certain areas, to allow light to pass from the internal face 12 to the external face 14, which makes it possible to backlight these areas in order to inform a user of the presence of a heated zone or another functional zone, for example.

According to one embodiment, the decorative layer 4 is attached directly to the support layer 2, in which case a bonding layer 16n, for example a layer of glue, adhesive or heat-activatable polypropylene, extends between the outer face 10 of the support layer 2 and the inner face 12 of the decorative layer 4. Alternatively, as will be described later, a layer of material 5, and possibly other additional layers, is arranged between the support layer 2 and the decorative layer 4, in which case a connecting layer 16 extends between the layer of material 5, or an additional layer, and the internal face of the decorative layer 4 (Figs. 1 and 3). It is understood that the decorative layer 4 can be fixed in another suitable way to the support layer 2 or to another layer. Such fixing can for example be obtained by sewing, by overmolding, by welding or by foaming a bonding layer, in particular depending on the materials used to produce the support layer 2 and/or the decorative layer 4.

Alternatively, the trim element 1 has no decorative layer 4 and the outer surface 14 of the trim element is formed by the outer face of the support layer 2 and/or by the layer of material 5 and/ or by a protective film 7.

The functional element 6 comprises at least one layer of material 5 made of a composite material comprising natural fibers in a pyrolyzed polypropylene matrix, also referred to below by the terms "pyrolyzed NFPP". Advantageously, the composite material comprising natural fibers in a polypropylene matrix which is pyrolyzed to form the pyrolyzed NFPP is of the same nature as the NFPP forming the support layer 2. More particularly, the pyrolyzed NFPP is for example obtained by residues and/or NFPP waste used to make the support layer 2 and/or other NFPP elements, for example produced in the same production plant as that which produces the packing element 1 according to the invention. In other words, the NFPP which is pyrolyzed to produce the layer of material 5 is for example recycled from NFPP used for other purposes. Consequently, the material layer 5 can be produced at reduced costs and makes it possible to reduce the production of waste in the factory.

Material layer 5 is an electrically conductive layer, which means that the NFPP is pyrolyzed to create an electrically conductive material such as a carbon-containing material. More particularly, the proportion of carbon in the pyrolyzed NFPP is for example greater than 60%. When the functional element 6 forms a resistive element to heat a heated zone of the external surface 14 of the packing element 1, by adjusting the density of carbon, by its quantity and its distribution in the layer of material 5, it is possible to easily set the maximum heating temperature of the resistive element.

The layer of material 5 extends over at least part of the internal face 8 yes, as represented in FIGS. 1 and 3, over at least part of the external face 10 of the support layer 2, more particularly in a or areas in which functionality is to be provided on the outer surface 14 of the packing element. According to one embodiment, the layer of material 5 extends over the entire surface of the face of the support layer 2 on which the layer of material 5 is applied. According to one embodiment, the material layer 5 is applied directly to the support layer 2, which means that there is no intermediate layer between the support layer 2 and the material layer 5. According to a another embodiment, the layer of material is first applied to a protective film 7 made of a plastic material, for example polypropylene, and the layer of material 5 is applied to the support layer with the protective film 7, interposed between the layer of material 5 and the support layer 2 as shown in the , the protective film 7 being for example glued or laminated on the support layer 2. Alternatively or in addition, a protective film 7 is applied to the outer face of the material layer 5 opposite the support layer 2. The film protector 7 is used to receive the pyrolyzed natural fibers of the layer of material 5 and to bind them together. As a variant, the protective film or films are made of a nonwoven or web. The layer of material 5 matches the shape of the part of the face of the support layer 2 which is covered by the layer of material 5. The layer of material 5 has for example a thickness of between 0.3 mm and 1.5 mm. The support layer 2, the layer of material 5 and the protective film or films 7 are for example laminated together, as will be described later.

In the case where the external surface 14 is formed by the external face 10 of the support layer 2, the material layer 5, and possibly the protective film 7, are for example fixed on the internal face 8 of the support layer 2

It should be noted that, in addition to forming a functional element 6, the layer of material 5 can also be used to form a reinforcing layer of the support layer 2. In this case, the layer of material 5, in particular when 'it extends over the entire surface of the support layer 2 or in areas in which the support layer 2 must be reinforced, improves the mechanical characteristics of the packing element 1, in particular in terms of rigidity and self-supporting, in particular when the support layer 2 is made of composite material.

According to an embodiment shown in Figs. 1 and 2, the functional element 6 is formed by an electrical circuit formed by a pattern 18 extending through at least part of the support layer 5.

The pattern 18 formed in the layer of material 5 comprises at least one conductive zone 20 formed by the pyrolyzed NFPP of the layer of material 5 and at least one non-conductive zone 22 formed by a through opening in the thickness of the layer of material 5. The shapes of the conductive area 20 and of the non-conductive area 22, an example of which is shown in the , are arranged so that the pattern 18 forms a functional element when the conductive zone 20 is supplied with electricity. Such a functional element is arranged to perform a function of interaction with a vehicle passenger on the outer surface 14 of the trim element. In other words, pattern 18 is such that it defines an electrical circuit forming functional element 6 when the circuit is energized. Depending on the functional zone, for example a zone to be heated, and its shape, a pattern can comprise several distinct conductive zones 20 and non-conductive zones 22 . In general, the pattern 18 comprises a non-conductive zone 22 surrounding the conductive zone or zones 20 in order to isolate the electric circuit forming the functional element from the rest of the layer of material 5.

When the functional element 6 is a heating element, the pattern 18 is arranged to form a resistive circuit, preferably extending over the outer face 10 of the support layer 2 in order to be closer to the outer surface 14 of the trim element 1, as shown in the . Such a resistive circuit makes it possible to heat a part of the outer surface 14 of the packing element opposite the pattern 18 when the conductive zone 20 of the pattern 18 is supplied with electricity. The shape of the resistive circuit corresponds for example to the shape of the heated zone on the external surface 14 of the packing element 1. Thus, as represented on the , the contour of the pattern 18 is for example circular and comprises several conductive zones 20 having a spiral shape separated by non-conductive zones 22 also having a spiral shape. At the end of the conductive zones 20, two connection terminals 24 are provided for connection to a current source (not shown), as will be described later. This shape of the pattern is given by way of example only and it is understood that other shapes may be provided depending on the shape of the zone to be heated on the outer surface 14 of the packing element 1. According to a embodiment, the conductive zone of the pattern 18 is formed by an enlarged zone of the functional layer and the through-opening(s) forming the non-conductive zone(s) are formed by the outline of this enlarged zone.

According to one embodiment, a part of the electric circuit forming the functional element 6, for example the part of the circuit which is heated when the functional element 6 is powered in the case of a heating element, is formed in the layer of material 5 applied to the external face 10, and another part of the electric circuit, more particularly the part of the circuit which includes the connection terminals 24, is formed on the internal face 8 of the support layer 2. The two parts of the electric circuit are connected together by one or more connection elements, such as connection rods, extending through the support layer 2. Such a connection element is for example formed by a conductive material filling an orifice extending in the support layer 2 between the parts of the electrical circuit connected together. This embodiment is advantageous for facilitating the connection of the electrical circuit to a current source, as will be described later. In this case, the circuit which includes the connection terminals 24 is for example formed by pyrolyzed NFPP tracks applied to the internal face 8 of the support layer 2 or by another pattern formed in an additional layer of material applied to the least part of the internal face 8 of the support layer 2.

It is understood that the functional element 6 is not necessarily a heating element. Thus, the electrical circuit forming the functional element is for example a capacitive circuit to form a tactile surface, a tactile slider, a tactile button or a proximity sensor on the external surface 14 of the trim element 1, a resistive circuit flexible which can be deformed to detect pressure on the outer surface 14 of the packing element 1 to form a pressure sensor. Such a functional element is also formed by a pattern formed in the layer or layers of material 5. Several functional elements can also be provided in one or more layers of material 5. These functional elements can be of the same nature, for example several elements of heating, or of a different nature and are each formed by distinct patterns.

According to another embodiment shown in the wherein the functional element is a heating element, the functional element 6 further comprises two electrodes 26 applied to the layer of material 5. The electrodes 26 are spaced from each other and are applied to different areas of the layer of material 5. The part of the layer of material 5 which extends between the zones on which the electrodes 26 are applied forms a heating part 28, which is heated by the Joule effect when an electric current passes through this part heating element 28 from one electrode 26 to the other electrode 26. Consequently, according to this embodiment, only the outer contour of the heating part 28 forming the pattern 18 must be cut to form a non-conductive zone and the method of making of the packing element 1 can be simplified. According to the embodiment of the , the layer of material 5 extends over the outer face of the support layer. As a variant, the layer of material 5 extends over the internal face of the support layer 2. According to a variant, the electrodes 26 are inserted into the layer of material 5.

Functional element 6 is supplied with electricity by at least one current source (not shown).

According to the embodiment shown in Figs. 1 and 2, the current source is more particularly electrically connected to one or more conductive zones 20 of pattern 18, for example connected to each connection terminal 24 of pattern 18. The current source is connected to the conductive zone for example by a electric cable 34 connected directly or by an electric connector 36 to the conductive zone 20 of the pattern 18. When a connector 36 is provided, it extends for example in a through opening of the support layer 2 of the internal face 8 to the outer face 10 of the support layer 2, as shown in the . The electrical cable 34 is then connected to the electrical connector 36 on the side of the internal face 8 of the support layer 2 and the electrical connector 36 is connected to the conductive zone 20 on the side of the external face 10 of the support layer 2. According to an embodiment described above, the electric cable 34 can be connected to the connection terminals 24 extending on the internal face 8 of the support layer 2, the electric current supplying the functional part of the electric circuit by the element or elements connection extending through the support layer 2. The electric cable 34 is for example connected to the electrical system of the vehicle which then forms the current source. When several circuits are provided in the layer(s) of material 5, each circuit is powered by the same current source or by several current sources via electric cables 34.

According to the embodiment of the , the current source is connected to the electrodes 26 by electrical cables 34. The same type of connection as in the embodiment of the can be used, i.e. the cables are either connected directly to the electrodes 26 as shown in the , or electrical connectors are provided in the support layer 2. The electrodes 26 can then pass a current through the heating part 28 of the layer of material 5 of the functional element 6.

According to a particular embodiment, the trim element may further comprise a transparent or translucent coating extending over the decorative layer 4 or over the support layer and/or the layer of material 5 and/or the protective film 7, through which the decorative layer 4 or the support layer and/or the material layer 5 and/or the protective film 7 is visible. Such a coating is for example a varnish or a translucent film, for example based on polypropylene, making it possible to protect the layer which extends underneath and in particular to avoid degradation of the pattern or patterns 18. It is particularly advantageous to make the layer of visible support in the case where the support layer has a satisfactory appearance, for example in the case of a layer made of NFPP.

The packing element described above makes it possible to integrate one or more functional elements, for example in the same layer of material 5 applied to the faces of the support layer 2, thus reducing the complexity of the packing element 1 and allowing a simple positioning of these elements with respect to the support layer 2 and/or with respect to the decorative layer 4. In addition, the packing element 1 has a long service life. In particular, the layer of material 5 has a high thermal resistance and a low expansion on the support layer 2. The trim element can also be produced at reduced cost while offering increased comfort to the passengers of the vehicle.

A method of making a packing element 1 according to the embodiment of Figs. 1 and 2 will now be described.

A first step consists of the pyrolysis of a composite material comprising natural fibers in a polypropylene matrix to form a layer of material 5. As described previously, the NFPP pyrolyzed during this step comes, for example, from residues and/or waste from NFPP for example obtained during the production of the support layer 2 or another vehicle part. During this pyrolysis step, the proportion of carbon in the layer of material 5 can be adjusted to determine the heating temperature of the functional element 6 in the case of a heating element, as described previously.

Material layer 5 is then applied to support layer 2, for example with a protective film 7 as described previously. More particularly, the support layer 2, the layer of material 5 and the protective film 7 are for example laminated together.

Pattern 18 is then made in material layer 5 to form functional element 6. conductors 22. By "throughout" is meant that the layer of material 5 is cut over its entire thickness. The shape of the through opening(s) in the layer of material 5 defines the shape of the pattern 18 and of the conductive zone(s) 20 thereof. The layer of material 5 is for example hollowed out by means of laser radiation, which makes it possible to define the shape of the pattern 18 very precisely. As a variant, the layer of material 5 is cut by chemical attack, by milling or by mechanical drilling in the carbon material. As described above, several patterns can be cut in the layer of material 5.

It should be noted that the pattern or patterns in the material layer 5 can be cut out in the material layer 5 before the assembly of this layer on the support layer 2.

If necessary, the decorative layer 4 is then fixed, for example via a bonding layer 16, on the support layer 2 and/or on the material layer 5 and/or on the protective film 7 .

The conductive area(s) 20 are then connected to one or more current sources, for example when mounting the trim element 1 in the vehicle. When an electrical connector 36 is provided, it is for example introduced into a through hole previously made in the support layer 2. Similarly, when connection elements are provided, they are first introduced into through holes made previously in support layer 2.

Before or after the assembly of the layer of material 5 and/or the layer of decoration 4 on the support layer 2, a three-dimensional shaping step can be provided to give the support layer 2 the desired shape. When the three-dimensional shaping is carried out after the assembly of the layer of material 5 with the support layer 2, the shaping is easily carried out since the support layer 2 and the layer of material 5 have similar deformability characteristics. .

For the production of a packing element 1 according to , the method is the same as that described above except that electrodes 26 are connected to the layer of material 5. It will be understood that the two embodiments can be combined when several functional elements 6 are provided, for example one being formed by a pattern 18 in the layer of material 5 and another using electrodes 26 on the layer of material 5.

Claims (11)

Vehicle trim element (1) comprising at least one support layer (2) comprising an inner face (8) and an outer face (10), and at least one functional element (6) extending over the support layer (2), said functional element (6) being electrically connected to a current source to perform a function of interaction with a passenger of the vehicle on at least part of an outer surface (14) of the trim element, characterized in that the functional element (6) comprises at least one layer of material (5) in a composite material comprising natural fibers in a pyrolyzed polypropylene matrix. Trim element according to Claim 1, in which the layer of material (5) of the functional element (6) defines at least one electrical circuit formed by a pattern (18) extending through the thickness of the said layer of material (5), said pattern (18) comprising at least one conductive zone (20) made of a composite material comprising natural fibers in a pyrolyzed polypropylene matrix and at least one non-conductive zone (22) formed by a through opening in said material layer (5), said conductive layer (20) being electrically connected to a current source. A packing element according to claim 1 or 2, wherein the functional element (6) further comprises a pair of electrodes (26) in contact with the layer of material (5), said electrodes (26) being electrically connected to a current source for passing an electric current in the layer of material (5) between said electrodes (26). Packing element according to any one of Claims 1 to 3, in which the functional element (6) extends over the outer face (10) of the support layer (2) between the support layer (2) and a decorative layer (4) extending opposite the outer face (10) of the support layer (2) and forming the outer surface of the trim element. Packing element according to any one of claims 1 to 4, in which the support layer (2) is made of a composite material comprising natural fibers in a polypropylene matrix. Trim element according to any one of Claims 1 to 5, in which the layer of material (5) is applied to the support layer (2) with a protective film (7) made of plastic material, in particular polypropylene. Packing element according to any one of Claims 1 to 6, in which the composite material comprising natural fibers in a pyrolyzed polypropylene matrix is obtained by pyrolyzing residues and/or waste of a composite material comprising natural fibers in a polypropylene matrix. Packing element according to any one of Claims 1 to 7, in which the proportion of carbon in the composite material comprising natural fibers in a pyrolyzed polypropylene matrix forming the layer of material (5) is greater than 60%. Trim element according to any one of Claims 1 to 8, in which the functional element (6) is a resistive element arranged to heat at least part of the outer surface (14) of the trim element when the functional element (6) is powered by a current source. Process for producing a packing element according to any one of Claims 1 to 9, comprising the following steps:
- pyrolyzing a composite material comprising natural fibers in a polypropylene matrix to form a layer of material (5),
- applying the layer of material (5) to a support layer (2),
- forming a functional element (6) in the layer of material (5), and
- electrically connecting the functional element (6) to a current source. A method according to claim 10 for producing a packing element according to claim 2, wherein the layer of material (5) is cut by laser etching, chemical etching, milling or mechanical drilling in the composite material comprising natural fibers in a matrix of pyrolyzed polypropylene to form an electrical circuit in the layer of material (5).