A method for manufacturing a three-dimensionally shaped trim piece made from woven or knitted textiles and polymers, particularly for motor vehicles.

Abstract

The invention relates mainly to a method for manufacturing a three-dimensionally formed garment part, which is essentially characterized in that it comprises at least the steps of: preparing an intermediate polymeric substrate (5) formed by injecting polymer under pressure into an injection molding machine comprising a mold (1), opening the mold (1) for a time ensuring the cooling of the polymeric substrate (5) to a temperature below its melting point, and positioning a woven or knitted textile (6) opposite the formed polymeric substrate (5), forming the assembly consisting of the textile (6) and the polymeric substrate (5) in the injection molding machine by closing the mold (1) and maintaining it under pressure, concurrently and / or prior to the forming operation, the polymeric substrate (5) is heated to a temperature above its melting point, opening the mold (1) and ejecting the part,and obtaining a covering piece comprising the woven or knitted textile (6) covering the hardened polymer substrate (5), which woven or knitted textile (6) is partially embedded in said hardened polymer (5). Figure to be published with the abbreviation: Fig. 3,

Description

Title of the invention: Method for manufacturing a three-dimensional trim piece made from woven or knitted textiles and polymers, particularly for motor vehicles technical field

[0001] The invention relates to the field of decorative trim parts for motor vehicles. The invention also relates to a method for manufacturing such a trim part. PRIOR ART AND DISADVANTAGES OF PRIOR ART

[0002] Textile trim pieces are well known in the automotive industry. These pieces are mainly found in the passenger compartment of the vehicle. Examples include door panels, the interior of the front window base, and the central pillar between the front and rear windows.

[0003] These parts must meet several requirements. First, they must be structurally sound, that is, have sufficient structural strength to ensure, in particular, their function as fasteners. This structural strength is generally provided by the presence of a polymer layer, for example, polypropylene. The cladding parts must also provide an aesthetic effect on their facing side.

[0004] It is known to produce these garment pieces by injecting molten polymer onto the back side of the garment fabric in an injection molding machine. A non-woven fabric, impermeable to the molten polymer, is first placed on the back side of the garment fabric, thus preventing any mixing of the polymer with the garment fabric. The resulting garment piece consists of three layers: the garment fabric, the non-woven fabric, and the hardened polymer.

[0005] While such garments are satisfactory in terms of appearance, they require the use of a material, non-woven textile, which serves no function in the garment's use, unnecessarily increasing manufacturing costs and limiting its recyclability. Furthermore, any aesthetic modification of the garment requires the use of a different textile, thus limiting the possibilities for aesthetic changes.

[0006] For large parts formed in three dimensions, there is also the added difficulty of controlling the structural homogeneity of the covering part, including at the level of its protruding edges. OBJECTIVE OF THE INVENTION

[0007] The invention aims to overcome the aforementioned drawbacks by proposing a manufacturing process for a three-dimensionally formed trim piece with reduced manufacturing cost, capable of providing a greater choice in aesthetics and ensuring the production of a trim piece that meets the criteria of the field and is homogeneous over its entire surface.

[0008] The invention also aims to facilitate the manufacture of such a part by a simple, fast process and generating a minimum cost. DESCRIPTION OF THE INVENTION

[0009] To this end, the invention relates to a method for manufacturing a three-dimensionally formed trim piece, characterized in that it comprises at least the following steps: - preparation of an intermediate polymeric substrate formed by injecting polymer under pressure in an injection molding machine comprising a mold that can be moved between an open inactive position and a closed active injection and / or forming position, - opening of the mold and positioning of a woven or knitted textile opposite the polymeric substrate formed in place in the mold, - Forming of the assembly consisting of the textile and the polymer substrate in the injection molding machine by closing the mold and maintaining pressure, - concurrently and / or prior to the forming operation, the polymeric substrate is brought to a temperature above its melting point, - cooling and hardening of the polymeric substrate (5,5a,5b), - opening of the mold and ejection of the part, and - obtaining a covering piece comprising the woven or knitted textile covering the hardened polymer substrate, which woven or knitted textile is partially embedded in said hardened polymer which occupies at least the interstices between the warp and weft yarns without totally covering the covering face of the textile so that said covering face comprises an alternation of hardened polymer and warp and / or weft yarns of the woven or knitted textile.

[0010] The process of the invention may also include the following optional features considered individually or according to all possible technical combinations: - before the forming operation, the textile is positioned in the mold and is carried out opposite the face of the injection of the polymeric substrate. - according to a first variant, the heating of the polymeric substrate is carried out by infrared heating prior to the forming operation. - Infrared heating is achieved by introducing an infrared heating plate into the open mold in relation to the polymeric substrate. - According to a second variant, the heating of the polymeric substrate is achieved by heating at least a part of the mold in contact with the polymeric substrate. (5,5a,5b) on the textile side (6) in the closed position at least during the forming operation at a temperature above the melting temperature of the polymeric substrate. - the heating of the mold is achieved by the circulation of a hot fluid in channels made in the thickness of at least part of the mold. - the heating temperature of the polymeric substrate is more than 10°C higher than its melting temperature. - the polymeric substrate is made of polypropylene, and the heating temperature of the polymeric substrate is above 160°C, preferably between 170 and 200°C. - The cooling and hardening stage of the polymeric substrate is carried out when the mold is closed.

[0011] The invention finally relates to the use of the trim piece obtained by the process previously stated to create a decorative element in the passenger compartment of a motor vehicle. PRESENTATION OF THE FIGURES

[0012] Other features and advantages of the invention will become clear from the description given below, by way of example and not limitation, with reference to the accompanying figures, among which: Fig. 1 schematically represents the mold, in the open position, of the injection press used to implement the process of the invention; Figure 2 schematically represents the first step of the process of the invention for producing a formed polymeric substrate. Figure [Fig.3] schematically represents a first variant of the garment construction in which the textile is positioned in the mold and the polymeric substrate formed is heated by infrared; Figure 4 schematically represents the forming step of the assembly consisting of the textile and the polymeric substrate following the heating of the polymeric substrate according to the first embodiment variant; Figure 5 schematically represents a second variant of the embodiment of the covering part in which the polymeric substrate is heated by the mold having channels for the circulation of hot fluid within its thickness; Figure 6 schematically represents the forming step of the assembly consisting of the textile and the polymeric substrate following the heating of the polymeric substrate according to the second embodiment variant; Figure 7 schematically represents the garment piece according to a first embodiment obtained by the process of the invention according to one of the two variant embodiments, which piece is made from a woven textile having a plain weave and a light-colored polymeric substrate, and Figure 8 schematically represents the garment according to a second embodiment obtained by the process of the invention according to one of the two variant embodiments, which garment is made from a woven textile having a twill weave and a dark-colored polymeric substrate. DETAILED DESCRIPTION OF THE INVENTION

[0013] It is first 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 easily be found by referring to another figure.

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

[0015] The invention proposes a method for manufacturing a trim piece formed in three dimensions, in particular for making parts intended to cover certain parts of a motor vehicle interior, for example, and without limitation, door panels, the inside of the front window base or the middle pillar between the front and rear windows.

[0016] The cover piece of the invention is bi-material in that it comprises a layer of woven or knitted textile on a polymer substrate. The woven or knitted textile is also partially embedded in the polymer substrate. More precisely, the polymer occupies at least the spaces between the warp and weft yarns of the textile when it is woven and may extend beyond these spaces on the side facing the cover piece without completely covering this side. Thus, on its side facing, the cover piece of the invention presents an alternation of polymer and warp and / or weft yarns.

[0017] The cover piece of the invention does not include a layer of non-woven or non-knitted textile, which reduces its manufacturing costs compared to cover pieces of the prior art. Furthermore, the absence of a non-woven or non-knitted textile layer allows the polymer to permeate the cover textile, giving it both mechanical strength and an aesthetic effect. During the manufacturing process, the molten polymer of the polymeric substrate fills at least the spaces between the warp and weft yarns of the textile, revealing its color on the cover side. Thus, by using the same textile and changing the color of the polymer, it is possible to modulate the overall aesthetic effect of the cover piece, offering multiple aesthetic choices. Moreover, the presence of only two materials (woven textile and polymer) allows to ensure simpler recycling than for the dressing piece of the earlier art which comprises at least three different materials.

[0018] The invention thus runs counter to what was sought in the prior art, namely, an absence of contact between the polymer and the covering textile. By forcing this contact, to the point of partially submerging the covering textile in the molten polymer, it is possible to produce a covering garment that meets the requirements in this field, without using non-woven textiles.

[0019] Any woven or knitted textile with interstices can be used within the scope of the invention. However, the invention more advantageously provides for the use of, as preferred, two woven textiles having respectively a plain weave and a twill weave. These two weaves are well known in the prior art.

[0020] Plain weave is a weave in which odd and even threads alternate with each weft pass, over and under the weft. Twill is a weave characterized by regular diagonal ribs on the right side, produced by the shifting of the weft threads by one thread with each weft pass. The weft thread passes under a warp thread, then over several other warp threads, shifting by one thread with each pass. Unlike plain weave, twill has a right side and a wrong side.

[0021] In the context of the invention, a woven textile with warp and weft yarns of the same color may be used, or a woven textile with one color for the weft yarns and another color for the warp yarns. It may also be provided that the warp and / or weft yarns have several different colors. On the final garment, the color of the polymer, which will occupy at least the spaces between the warp and weft yarns, will be added to these different colors.

[0022] The polymer is chosen from among the polymers that can be used in an injection molding process, for example polypropylene, polyethylene, acrylonitrile butadiene styrene, polycarbonate, or an alloy of acrylonitrile butadiene styrene and polycarbonate. While not limited to these, polypropylene is preferred.

[0023] The process of the invention is implemented in a single piece of equipment, namely an injection molding machine. The injection molding process is a process whose general aspects are well known to those skilled in the art.

[0024] With reference to [Fig. 1], the injection molding machine comprises an injection mold 1 having, in a known manner, a movable platen 2, a fixed platen 3, and a polymer injection channel 4 formed in the thickness of the fixed platen 3 and opening onto molten polymer supply means not shown. The mold 1 is actuable between an open inactive position, most often used for ejection the part after forming, and an active closed position for injection and forming, or for forming only by pressing the moving plate 2 against the fixed plate 3.

[0025] With reference to [Fig.2], the polymeric substrate formed, for example in polypropylene, is prepared by injection into the injection mold under the following conditions: the temperature of the sleeve is between 200 and 280°C and the injection pressure is between 100 and 300 bars.

[0026] Preferably, the tooling temperature is about 40°C, the polypropylene is brought to a temperature of 250°C, and the injection pressure of the polypropylene is between 100 and 300 bars, preferably 200 bars.

[0027] Once the injection has been carried out, an intermediate substrate 5 is obtained whose shape corresponds to the shape conferred by the junction plane between the moving plate 2 and the fixed plate 3.

[0028] The mold 1 is then opened (figures 3 and 5) to introduce the textile 6 between the moving plate 2 and the fixed plate 3 in the mold 1 opposite the formed polymeric substrate 5 which remains attached to the fixed plate 3. More precisely, the textile 6 is positioned in the open mold 1 opposite the face 7 of the formed polymeric substrate 5 which is opposite its injection face 8. The opening of the mold leads to the cooling of the formed polymeric substrate 5 which then has a temperature of the order of 80 to 100°C.

[0029] According to the invention, the polymeric substrate 5 is reactivated by heating it before and / or concurrently with the subsequent forming process to make it malleable and allow the textile 6 to become embedded in the polymeric substrate 5 by forming. Reactivation of the polymeric substrate 5 consists of heating it to a temperature above its melting point. Preferably, the heating temperature is at least 10 degrees above the melting point of the polymeric substrate. For example, when the polymeric substrate is polypropylene, the heating temperature of the substrate is above 160°C, preferably above 170°C, and more preferably between 180 and 200°C.

[0030] To achieve this, two alternative embodiments are described.

[0031] With reference to [Fig. 3] and according to a first embodiment, the heating of the polymeric substrate 5 is carried out by infrared heating. To do this, an infrared heating insert 9 is introduced into the open mold 1 between the textile 6 and the formed polymeric substrate 5, the heating face being directed towards the formed polymeric substrate 5.

[0032] After reactivation of the polymeric substrate 5, the heating insert 9 is removed from the mold and the forming operation of the assembly consisting of the textile 6 and the reactivated polymeric substrate 5, during which the textile 6 becomes embedded in the polymeric substrate 5, is carried out by closing the mold 1 and keeping the mold closed by pressing the two parts 2, 3 of the mold 1 against each other for a The closing time should be between 15 and 25 seconds with sufficient closing force. Preferably, the applied pressure should be between 50 and 150 bar.

[0033] After forming and embedding the textile 6 in the polymeric substrate 5, the cooling of the resulting garment, and more particularly of the polymeric substrate, can be ensured in the mold 1, which is held in a closed position by means of cooled fluid circulation channels (not shown) integrated into the thickness of the two parts 2 and 3 of the mold 1. In this scenario, the cooling of the garment therefore occurs in the closed mold 1, and the polymeric substrate, now integrated into the textile, hardens. The mold 1 is then opened, and the garment is ejected. The resulting garment will be described in more detail with reference to Figures 7 and 8.

[0034] According to a second embodiment and with reference to Figures 5 and 6, the heating of the polymeric substrate 5 is carried out in and by the mold 1. To this end, circulation channels for a heated fluid 10 are integrated into the thickness of the movable plate 2 in contact with the face of the polymeric substrate 5 onto which the textile 6 is applied. The fluid is heated to a temperature higher than the melting temperature of the polymeric substrate 5 and preferably more than 10°C above the melting temperature of the substrate 5.

[0035] Thus, when the mold 1 is closed and held in this position in the same way as for the forming operation of the first embodiment, the heat diffused into the metal mold 1 reactivates the polymeric substrate 5 by raising it to a temperature above its melting point. It thus becomes sufficiently malleable so that, through the forming operation, the textile 6 becomes embedded within the thickness of the substrate 5.

[0036] As with the first variant, the mold 1 is held in the closed position by pressing the two parts 2, 3 of the mold 1 against each other for a period of between 15 and 15 seconds with sufficient closing force. Preferably, the applied pressure is between 50 and 150 bar.

[0037] After forming and as for the first variant, the cooling of the resulting dressing part and more particularly of the polymeric substrate, can be ensured in the mold 1 maintained in a closed position by means of cooled fluid circulation channels (not shown) integrated into the thickness of the two parts 2, 3 of the mold 1. In this hypothesis, the cooling of the dressing part therefore takes place in the closed mold 1, then the mold 1 is opened and the part is ejected.

[0038] As illustrated in Figures 7 and 8, during the forming operation, the polymeric substrate 6 passes through the thickness of the textile 5, filling at least the interstices between the weft and warp yarns.

[0039] More specifically, and with reference to [Fig. 7], when the woven textile 6a has a plain weave, which has been illustrated by way of example with light grey weft yarns and Given that the warp yarns 12a are dark gray, and the polymer 5a is white, the facing face 14a of the resulting facing piece 15a comprises alternating white polymer 5a, light gray weft yarns 11a, and dark gray warp yarns 12a. This results in a facing face 14a of the facing piece 15a composed of three colors.

[0040] The cover piece 15a has been schematically represented as comprising hardened polymer 5a in the interstices 13a of the woven textile 6a, but also in the areas where the weft yarns pass under the warp yarns and vice versa. However, this representation is schematic because, while the polymer does fill the interstices 13a, it spreads more randomly over the adjacent areas of the interstices 13a according to the surface texture of this textile 6a.

[0041] With reference to [Fig. 8], when the woven textile 6b has a twill weave, illustrated by way of example with light gray weft yarns 11b and dark gray warp yarns 12b, and the polymer substrate 5b is black, the facing 14b of the resulting garment piece 15b comprises alternating black polymer 5b, light gray weft yarns 11b, and dark gray warp yarns 12b. This results in a facing 14b of the garment piece 15b composed of three colors.

[0042] The covering piece 15b has also been schematically represented as comprising hardened polymer 5b in the interstices 13b of the woven textile 6b, as well as in the areas where the weft yarns pass under the warp yarns and vice versa. However, as with the plain weave, this representation is schematic because, while the polymer 5b does fill the interstices 13b, it spreads more randomly over the areas adjacent to the interstices 13b, depending on the surface texture of this textile 6b.

[0043] The trim piece of the invention 15a,15b finally has a fit allowing it to be used as a trim piece in the passenger compartment of a motor vehicle.

Claims

Demands

1. A method for manufacturing a garment, characterized in that it comprises at least the steps of: - preparing an intermediate polymeric substrate formed (5, 5a, 5b) by injecting polymer under pressure in an injection molding machine comprising a mold (1) actuable between an open inactive position and a closed active injection and / or forming position, - opening the mold (1) and positioning a woven or knitted textile (6, 6a, 6b) opposite the formed polymeric substrate (5, 5a, 5b) in place in the mold (1), - forming the assembly consisting of the textile (6, 6a, 6b) and the polymeric substrate (5, 5a, 5b) in the injection molding machine by closing the mold (1) and maintaining it under pressure, - concurrently and / or prior to the forming operation, the polymeric substrate (5, 5a, 5b) is heated to a temperature above its melting point, - cooling and hardening the polymeric substrate (5,5a,5b),- opening of the mold (1) and ejection of the part, and - obtaining a covering piece (15a, 15b) comprising the woven or knitted textile (6, 6a, 6b) covering the hardened polymer substrate (5, 5a, 5b), which woven or knitted textile (6, 6a, 6b) is partially embedded in said hardened polymer (5, 5a, 5b) which occupies at least the spaces (13a, 13b) between the warp yarns (12a, 12b) and the weft yarns (11a, 11b) without totally covering the covering face (14a, 14b) of the textile (6, 6a, 6b) so that said covering face (14a, 14b) comprises an alternation of hardened polymer (5, 5a, 5b) and warp yarns (12a, 12b) and / or weft yarns (11a, 11b) of the textile woven or knitted (6,6a,6b).

2. Method according to the preceding claim, characterized in that before the forming operation, the textile (6,6a,6b) is positioned in the mold (1) opposite the injection face (7) of the polymeric substrate (5,5a,5b).

3. A method according to any one of the preceding claims, characterized in that the heating of the polymeric substrate (5,5a,5b) is carried out by infrared heating prior to the forming operation.

4. Method according to the preceding claim, characterized in that the infrared heating is carried out by introducing into the open mold (1) an infrared heating plate (9) opposite the polymeric substrate (5,5a,5b).

5. A method according to any one of claims 1 to 3, characterized in that the heating of the polymeric substrate (5,5a,5b) is carried out by heating at least a part of the mold (1) in contact with the polymeric substrate (5,5a,5b) on the side of the textile (6) in closed position at least during the forming operation to a temperature higher than the melting temperature of the polymeric substrate (5,5a,5b).

6. Method according to the preceding claim, characterized in that the heating of the mold (1) is achieved by the circulation of a hot fluid in channels (10) formed in the thickness of at least part of the mold (1).

7. A method according to any one of the preceding claims, characterized in that the heating temperature of the polymeric substrate (5,5a,5b) is more than 10°C above its melting temperature.

8. A method according to any one of the preceding claims, characterized in that the polymeric substrate (5,5a,5b) is made of polypropylene, and in that the heating temperature of the polymeric substrate is greater than 160°C, preferably between 170 and 200°C.

9. A method according to any one of the preceding claims, characterized in that the step of cooling and hardening the polymeric substrate (5,5a,5b) is carried out when the mold (1) is closed.

10. Use of the trim piece obtained by the process of the preceding claims to create a decorative element in the passenger compartment of a motor vehicle.

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