Polyester trim part, in particular for a motor vehicle, and associated manufacturing process

Abstract

The invention relates mainly to a motor vehicle trim part, which is essentially characterized in that it is made of a single-material polyester, and in that it comprises at least one support layer (2) based on compressed polyester fibers, and a structural layer (3) overmolded on the internal face of said support layer by injection of polyester. The invention also relates to a method for manufacturing said trim part which comprises at least the steps of: providing a polyester felt (6), compressing said felt to form a compressed felt (8), shaping the compressed felt (8) obtained in the previous step to form the support layer (2), and injecting polyester onto the internal face (4) of the support layer (2) to form the structural layer (3). Figure to be published with the abstract: [Fig. 2]

Description

Title of the invention: Polyester trim part, in particular for a motor vehicle, and associated manufacturing method Technical field

[0001] The invention falls within the field of trim parts for motor vehicles. The invention also relates to a method of manufacturing such a trim part. Prior art and disadvantages of prior art

[0002] Textile trim parts are well known in the automotive field. These parts are mainly found in the passenger compartment of the vehicle. Examples include the door panels, the inside of the front window pillar or the center pillar between the front and rear windows and the flange of the central armrest.

[0003] These parts must have sufficient structural strength to ensure in particular their function as a fixing part.

[0004] As described in publication EP2674274, it is known to manufacture such a trim piece by molding a support made of a first plastic material on an insert which is made of a second plastic material and which has been previously shaped and assembled to a complex integrating the visible decorative face of the trim piece.

[0005] Such a part comprises a plurality of different materials, most of which are non-recyclable. Furthermore, the plurality of materials and elements generates a multi-step manufacturing process involving a first step of assembling the complex to the insert, then the step of molding the support onto the insert.

[0006] In addition to having a non-eco-responsible character due to the use of the plurality of plastic materials, the method of the prior art does not allow the ornamental layer to be easily modified since this layer is applied to the insert even before the support is formed. Objective of the invention

[0007] The object of the invention is to overcome the aforementioned drawbacks by proposing an eco-responsible covering part, particularly in terms of recycling, and a method of manufacturing such a part having a limited number of steps while leaving the possibility of adding, or not, an ornamental face. Statement of the invention

[0008] To this end, the invention relates to a motor vehicle trim part which is characterized in that it is made of a single-material polyester, and in that it comprises at least one support layer based on compressed polyester fibers, and a layer structural overmolded on the internal face of said support layer by polyester injection.

[0009] The cladding part of the invention may also include the following optional characteristics considered in isolation or according to all possible technical combinations: - the support layer is made from a mixture of recycled polyester fibers and thermofusible polyester fibers. Preferably, such a support layer is shaped by thermocompression. • the structural layer includes a network of reinforcing ribs and / or technical elements. • the cladding part has an ornamental coating on the external face of the support layer. • the ornamental coating is made of polyester.

[0010] The invention also relates to a method of manufacturing the previously mentioned trim part, which is characterized in that it comprises at least the steps of: - supply of a polyester felt, - compression of said felt to form a compressed felt, - shaping the compressed felt by thermocompression to form the support layer, and - injection of polyester on the internal face of the support layer to form the structural layer.

[0011] The method of the invention may also include the following optional characteristics considered in isolation or according to all possible technical combinations: - the injection is carried out concomitantly with the thermocompression step. - the method comprises at least the steps of: - supply of a felt made from a mixture of recycled polyester fibres and thermofusible polyester fibres, - first hot compression of said felt to form a compressed felt, - shaping of the felt obtained by thermocompression to form the support layer, and - concurrently with the thermocompression step, injection of polyester onto the internal face of the support layer to form the structural layer. - the first hot compression of the felt (6) is carried out under pressure at a temperature between 180 and 220°C. - the process may include an additional step of adding an ornamental coating, for example polyester, to the external face of the support layer. Presentation of figures

[0012] Other characteristics and advantages of the invention will emerge clearly from the description given below, for information purposes only and in no way limiting, with reference to the appended figures, among which: [Fig.l] is a schematic representation from above of the covering part of the invention taken from the side of the external face of the support layer, [Fig. 2] is a schematic representation from above of the covering part of the invention taken from the side of the internal face of the support layer, also illustrating the structural layer overmolded on the internal face, [Fig. 3] is a schematic representation of a first step of the method of the invention according to a preferred embodiment during which a polyester felt undergoes a thermocompression step, [Fig. 4] is a schematic representation of a second step of the method of the invention according to the preferred embodiment during which the compressed felt is positioned in an injection press, [Fig. 5] is a schematic representation of a third step of the method of the invention according to the preferred embodiment during which the compressed felt is shaped in the press, and [Fig.6] is a schematic representation of a fourth step of the method of the invention according to the preferred embodiment concomitant with the third step and during which polyester is injected on the side of the internal face of the support layer to form the structural layer. Detailed description of the invention

[0013] It is first of all specified that in the figures, the same references designate the same elements regardless of the figure in which they appear and regardless of the form of representation of these elements. Similarly, if elements are not specifically referenced in one of the figures, their references can be easily found by referring to another figure.

[0014] It is also specified that the figures essentially represent embodiments of the subject of the invention but that there may be other embodiments which meet the definition of the invention.

[0015] The invention proposes a motor vehicle trim part made from a single material, namely polyester, which is a recyclable plastic and which can also be used in a recycled state.

[0016] With reference to figures 1 and 2, the covering part of the invention 1 comprises a support layer 2 based on polyester fibers, and a structural layer 3 made of polyester which is overmolded onto the internal face of the support layer 2. The layer support 2 may optionally be covered with an ornamental covering, not shown, advantageously made of polyester or polyester fibers.

[0017] The polyester structural layer 3 forms a network of reinforcing ribs and technical shapes, providing rigidity and functionality to the cladding part of the invention 1.

[0018] Nevertheless, the support layer 2 must have sufficient rigidity to ensure the general strength of the covering part.

[0019] To do this, the support layer 2 is obtained by compression, prior to and / or concomitantly with the overmolding of the structural layer 3.

[0020] More advantageously, the support layer 2 comprises a mixture of recycled polyester fibers and thermofusible polyester fibers and is thermocompressed prior to or concomitantly with the overmolding of the structural layer. The thermofusible polyester fibers provide, under the effect of heat, the required hardening and strength to the support layer 2, in addition to the compression effect of the fibers, and this, without using any material other than polyester.

[0021] As illustrated in Figures 1 and 2, the support layer 2 is shaped and has a hollow internal face 4 on which the structural layer 3 is overmolded. The support layer also has a substantially flat peripheral edge 5.

[0022] The method of manufacturing the covering part of the invention comprises three main phases, namely the compression, preferably hot, of a felt of polyester fibers, the shaping of the felt by thermocompression to obtain the support layer 2, and the injection of polyester onto the internal face of the support layer 2 to form the structural layer 3.

[0023] Advantageously, the felt comprises a mixture of recycled polyester fibers and thermofusible polyester fibers. Its shaping by thermocompression and the injection of polyester can be carried out in a single step in an injection press, thus reducing the number of steps in the process and simplifying the tooling used.

[0024] Preferably, the method comprises two compression phases. A first hot compression during which the felt is heated to the core to a temperature ensuring at least partial, preferably total, melting of the hot-melt polyester, and the concomitant application of a compression force to compress the fibers forming the felt by reducing its thickness by approximately 50% to 70%. The resulting compressed felt is still flat.

[0025] The second compression is a thermocompression step which leads to the shaping of the support layer during which the still hot or reheated felt is again subjected to the application of a compression force.

[0026] The method of manufacturing the covering part of the invention according to a preferred embodiment is described with reference to Figures 3 to 6.

[0027] A felt 6 ([Fig.3]) composed of a mixture of recycled polyester fibers and thermofusible polyester fibers. The felt 6 has a recycled fiber content of the order of 50% to 70% and a thickness of between 8 and 15 millimeters is placed in a press 7 made of two heating plates facing each other to undergo the first hot compression.

[0028] The plates are brought to a temperature between 180 and 220°C and are pressed against each other. The felt is brought to this same temperature between 180 and 220°C and the pressure applied to it is between 5 and 15 bars.

[0029] We then obtain a flat compressed felt 8 with a thickness reduced to 2 mm + / - 0.5 mm compared to the initial thickness.

[0030] The compressed felt 8 is placed ([Fig.4]) immediately in an injection press 9 comprising a mold 10, a movable platen 11, a fixed platen 12 and a polymer injection channel 13 to undergo the thermocompression operation, concomitant with the injection operation. Thus, the compressed felt 8 is always at temperature in the injection press to facilitate its shaping. Alternatively, the compressed felt 8 is cooled after the first compression step, then reheated before its introduction into the press, for example by infrared.

[0031] The compressed felt 8 is inserted between the two parts of the mold, its internal face 14 on the side of the polymer injection channel 14.

[0032] The two parts of the mold 10 are pressed against each other ([Fig. 5]) at a pressure of between 10 and 20 bars and held in this position by generating the shaping of the felt 8 as well as a new compression force leading to a reduction in the thickness of the felt 8 of the order of 0.5 mm. The support layer 2 of the covering part of the invention 1 is then obtained.

[0033] Simultaneously with the closing of the mold and thanks to a cutting blade integrated in the pressure, the peripheral cutting of the felt is carried out by forming the peripheral edge 5 of the covering part 1.

[0034] Also concomitantly with the closing of the mold, molten polyester 15 is injected on the side of the internal face 14 of the felt 8, forming the structural layer 3.

[0035] The injection is carried out according to the following operating conditions: - the temperature of the tool is approximately 20°C, - the polyester is heated to a temperature between 200 and 280°C, preferably 250°C, - the injection pressure of the polyester is between 50 and 150 bars, preferably 100 bars

[0036] After cooling and hardening of the polyester, the mold is opened and the covering part of the invention 1 is obtained as shown in Figures 1 and 2.

[0037] The external face of the support layer 2 can act as a covering. In this case, the felt used can have a surface mass of between 1000 and 2000 g / m 2, thus contributing to the rigidity of the covering part in addition to forming the decorative covering. Alternatively, the felt used can have a surface mass of between 200 and 600 g / m 2, thus forming only a decorative covering.

[0038] Alternatively, it is possible to provide for the addition of an ornamental coating on the external face of the support layer 2. Preferably, the ornamental coating is made of polyester, preferably at least partially recycled polyester, which makes it possible to maintain the recyclable nature of the covering part of the invention. The addition of the ornamental coating on the external face of the support layer 2 can be carried out at the same time as the thermocompression step by inserting the coating on the external face of the compressed felt 8 after the first hot compression step and before introduction into the injection press 9. Alternatively, the coating can be affixed after the production of the covering part comprising only the support layer 2 and the structural layer 3, by known methods of bonding or sheathing.According to the invention, the trim piece 1 is made partially from recycled polyester and is fully recyclable. In addition, its manufacturing process is simple and inexpensive.

Claims

Claims

1. Motor vehicle trim part, characterized in that it is made of a single-material polyester, and in that it comprises at least one support layer (2) based on compressed polyester fibers and which is shaped by thermocompression and made from a mixture of recycled polyester fibers and thermofusible polyester fibers, and a structural layer (3) overmolded on the internal face (4) of said support layer (2) by injection of polyester.

2. Covering part according to the preceding claim, characterized in that the structural layer (3) comprises a network of reinforcing ribs and / or technical elements.

3. A covering piece according to any one of the preceding claims, characterized in that it comprises an ornamental coating on the external face of the support layer (2).

4. A covering piece according to claim 4, characterized in that the ornamental covering is made of polyester.

5. Method of manufacturing the covering part according to any one of the preceding claims, characterized in that it comprises at least the steps of: - providing a polyester felt (6) made from a mixture of recycled polyester fibers and thermofusible polyester fibers, - thermocompression of said felt to form a compressed felt (8), - shaping the compressed felt (8) by thermocompression to form the support layer (2), and - injecting polyester onto the internal face (4) of the support layer (2) to form the structural layer (3).

6. Manufacturing method according to claim 5, characterized in that the injection is carried out concomitantly with the thermocompression step.

7. Manufacturing method according to any one of claims 5 and 6 for manufacturing the part according to any one of claims 1 to 4, characterized in that it comprises at least the steps of: - providing a felt (6) made of a mixture of recycled polyester fibers and thermofusible polyester fibers, - first hot compression of said felt (6) to form a compressed felt (8),

8.

9. - shaping the felt (8) obtained in the previous step by thermocompression to form the support layer (2), and, - concomitantly with the thermocompression step, injection of polyester onto the internal face (4) of the support layer (2) to form the structural layer (3). Manufacturing method according to the preceding claim, characterized in that the first hot compression of the felt (6) is carried out in a press at a temperature between 180 and 220°C. Manufacturing method according to any one of claims 5 to 8, characterized in that it comprises an additional step of adding an ornamental coating, for example polyester, on the external face (16) of the support layer (2).

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