Filling element comprising polypropylene on its external surface
A vehicle trim element using polypropylene fibers with varying melt flow indices forms a protective surface layer during thermoforming, addressing the cost and complexity issues of film addition, while maintaining the appearance and protecting natural fibers.
Patent Information
- Application Number
- FR2023000545
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-01-20
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2043-01-20
AI Technical Summary
The addition of a polypropylene film to vehicle trim elements to protect natural fibers from ultraviolet radiation and scratches increases costs and complicates production, while the natural fibers degrade over time.
A vehicle trim element composed of a body formed from non-woven or woven materials with two groups of polypropylene fibers having different melt flow indices, where the higher melt flow index fibers form a protective surface layer during thermoforming, encapsulating the natural fibers without the need for an additional film.
The solution provides a cost-effective and efficient protection of natural fibers from ultraviolet radiation and scratches without the need for an additional film, maintaining the appearance and integrity of the trim element.
Smart Images
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Abstract
Description
Title of the invention: Filling element comprising polypropylene on its external surface
[0001] The present invention relates to a vehicle trim element.
[0002] The invention also relates to a method for making such a trim element.
[0003] The invention applies for example to a trim element forming a door panel, a center console or dashboard covering of a vehicle or other.
[0004] Such a trim element makes it possible to give a vehicle interior a particular appearance. This appearance is conferred by the appearance of the trim element's external surface, visible from inside the vehicle. In order to maintain this appearance, it is known to add a polypropylene film to the external surface of the trim element's body to protect it, for example, from ultraviolet radiation and / or scratches, particularly when the body is made of natural fibers. Indeed, in such a trim element, it is desirable for the natural fibers to be visible from the outside of the trim element, even though they are relatively fragile and their appearance degrades over time under the effect of ultraviolet radiation.
[0005] The film can also be used to modify the appearance of the trim element by, for example, being colored or to produce a glossy effect.
[0006] However, the addition of such a film increases the costs of the trim element and complicates its production.
[0007] One of the aims of the invention is to overcome this drawback by proposing a filling element based on natural fibers which has a satisfactory appearance and whose external surface fragility is reduced.
[0008] To this end, the invention relates to a vehicle trim element comprising a body extending between an internal surface, intended to be turned towards a support of the trim element, and an external surface, opposite the internal surface and intended to be turned towards the passenger compartment of the vehicle, said body being formed from at least one non-woven or woven material comprising natural fibers, a first group of polypropylene fibers having a first hot melt index and a second group of polypropylene fibers having a second hot melt index, lower than the first hot melt index, the polypropylene from the fibers of the first group extending mainly in an upper layer of the body, said upper layer forming the external surface of the body.
[0009] The polypropylene from the fibers of the first group, having a higher melt flow index, tends to flow towards the outer surface of the body during the thermoforming of the filling element. Thus, the polypropylene from the fibers of the first group forms a surface layer that constitutes the outer surface of the body, which protects the natural fibers of the body without requiring the addition of a polypropylene film to perform this protective function.
[0010] The trim element according to the invention may comprise one or more of the following features, taken individually or in any technically feasible combination:
[0011] - the first hot fluidity index is substantially between [30g - 80g] / 10 minutes ;
[0012] - the second hot fluidity index is substantially between [0.7g - 30g] / 10 minutes;
[0013] - the upper layer has a thickness of approximately between 0.01 mm and 0.8 mm;
[0014] - the propylene from the fibers of the second group extends mainly in a lower layer of the body, said lower layer forming the internal surface of the body, the lower layer having a thickness greater than the thickness of the upper layer;
[0015] - the natural fibers are chosen from at least one of flax, hemp, kenaf and / or wood;
[0016] - the upper layer of the body comprises at least an additive conferring a function of protection against ultraviolet radiation and / or against scratches on the external surface of the body and / or discoloration on the external surface of the body.
[0017] According to another aspect, the invention relates to a method for making such a trim element, comprising the following steps:
[0018] - supply of at least one body formed of at least one layer of a non-woven material or woven comprising natural fibers, a first group of polypropylene fibers having a first hot melt index and a second group of polypropylene fibers having a second hot melt index, lower than the first hot melt index,
[0019] - thermoforming said body so as to give it the shape of the element of filling to be carried out, the heating temperature of the body being arranged to cause the fusion of the polypropylene fibers of the first group and the second group, the propylene from the fibers of the first group flowing towards the external surface of the body.
[0020] The method for implementing the invention may include one or more of the following features, taken individually or in any technically feasible combination possible:
[0021] - the body comprises a first layer formed by a non-woven or woven material comprising natural fibers and the first group of polypropylene fibers and a second layer formed by a non-woven or woven material comprising natural fibers and the second group of polypropylene fibers, the first layer and the second layer being thermoformed and assembled together during the thermoforming stage of the body;
[0022] - the body further comprises at least one intermediate non-woven or woven layer, comprising natural fibers and / or polypropylene fibers, said intermediate layer being disposed between the first layer and the second layer and being thermoformed and assembled with said first and second layers during the thermoforming stage of the body.
[0023] Other aspects and advantages of the invention will become apparent from the following description, given by way of example and with reference to the accompanying drawings, in which:
[0024] [Fig-1] - [Fig.1] is a schematic cross-sectional representation of an element of filling according to the invention, and
[0025] [Fig.2] - [Fig.2] is a schematic exploded perspective representation of a trim element body before its realization according to an embodiment of the trim element realization process.
[0026] With reference to [Fig.1], a trim element 1 is described comprising a body 2 extending between an internal surface 4 and an external surface 6. Such a trim element is, for example, intended to form a door panel, a dashboard or center console covering, or other.
[0027] The inner surface 4 is intended to be applied to a support of the trim element, i.e., to a surface of an element that the trim element is to cover, for example, a door panel, a dashboard or center console body, or the like. The outer surface 6 is intended to face the vehicle's passenger compartment and thus forms at least part of the visible surface of the trim element 1 when it is installed in the vehicle.
[0028] In what follows, the thickness is measured along the direction from the internal surface 4 to the external surface 6.
[0029] The body is formed from at least one nonwoven or woven material. A nonwoven material is defined as a material comprising fibers interlaced with each other in an irregular manner, the fibers being randomly oriented. Such a nonwoven material is produced, for example, by needle punching. A woven material is a material comprising fibers interlaced in a regular manner, forming, for example, warp and weft yarns. Such a woven material is obtained by weaving.
[0030] The body material, prior to its thermoforming which will be described later, comprises natural fibers, a first group of polypropylene (PP) fibers and a second group of polypropylene fibers. Such a material is known as NFPP for "Natural fibers polypropylene".
[0031] The natural fibers extend throughout the entire thickness of the body 2, that is, from the inner surface 4 to the outer surface 6. The natural fibers are, for example, selected from at least one of flax, hemp, kenaf, and / or wood. Natural fibers of different types, for example selected from the preceding list, may also be mixed within the body 2.
[0032] The first group of PP fibers exhibits a first melt flow index (MFI). The melt flow index characterizes the polypropylene of the fibers, providing information on the material's processing capabilities, particularly how the material flows when heated above the melting point of PP. The MFI is measured in accordance with ISO 1133 or ASTM D1238. In one embodiment, the first MFI is, for example, greater than 30 g / 10 minutes at a temperature of 230°C for a mass of 2.2 kg, for example, between 30 g and 80 g / 10 minutes.
[0033] According to one embodiment, at least one additive is added to the first group of PP fibers. This additive is arranged to provide protection against ultraviolet radiation and / or against scratches to the external surface 6 of the body 2 and / or coloring to the external surface 6 of the body, as will be described later.
[0034] The second group of PP fibers has a second IFC lower than the first IFC. According to one embodiment, the second IFC is for example less than 30g / 10 minutes at a temperature of 230°C for a mass of 2.2 Kg, for example between [0.7g - 30g] / 10 minutes.
[0035] According to a first embodiment, the PP fibers of the first and second groups extend equally throughout the entire thickness of the body 2, i.e., the body 2 is formed from a single layer comprising the natural fibers and the PP fibers of the first and second groups. The material comprises, for example, an equal proportion of natural fibers and PP fibers. That is, the material is composed of 50% natural fibers and 50% PP fibers of the first and second groups. Alternatively, the proportion of PP fibers varies between 30% and 70%. According to this embodiment, the natural fibers have a weight of substantially between 90 gsm and 1200 gsm (grams per square meter) when the body 2 is formed from a nonwoven fabric.
[0036] Alternatively, the body is formed from several layers assembled together at during the manufacturing of the filling element, as will be described in more detail later. Thus, as shown in [Fig. 2], the body 2 comprises at least a first layer 8, comprising natural fibers and PP fibers of the first group, and a second layer 10, comprising natural fibers and PP fibers of the second group. According to a particular embodiment shown in [Fig. 2], the body 2 further comprises at least an intermediate layer 12 extending between the first layer 8 and the second layer 10.
[0037] The first layer 8 extends between a lower surface 14 and an upper surface 16. The lower surface 14 extends over the second layer 10 or, where applicable, over the intermediate layer 12, and the upper surface 16 forms the external surface 6 of the body 2. The first layer 8 is formed from a nonwoven or woven material. The first layer 8 comprises, for example, 50% natural fibers and 50% PP fibers from the first group. Alternatively, the proportion of PP fibers from the first group in the first layer 8 is greater than 40%, up to 70% PP fibers from the first group. When the first layer 8 is formed from a nonwoven material, the weight of the natural fibers is, for example, substantially between 20 gsm and 300 gsm. The thickness of the first layer 8 is, for example, substantially between 0.1 mm and 0.4 mm.
[0038] The second layer 10 extends between a lower surface 18 and an upper surface 20. The lower surface 18 forms the inner surface 4 of the body 2, and the upper surface 20 extends against the lower surface 14 of the first layer 8 or, where applicable, against the intermediate layer 12. The second layer 10 is formed from a nonwoven or woven material. The second layer 10 comprises, for example, 50% natural fibers and 50% second-group PP fibers. Alternatively, the proportion of second-group PP fibers in the second layer 10 is greater than 40%, up to 70% second-group PP fibers. When the second layer 10 is formed from a nonwoven material, the weight of the natural fibers is, for example, substantially between 200 gsm and 2000 gsm. The thickness of the second layer 10 is greater than that of the first layer 8 and is, for example, approximately between 0.4 mm and 5 mm.
[0039] The intermediate layer 12 extends between a lower surface 22 and an upper surface 24. The lower surface 22 extends over the upper surface 20 of the second layer 10, and the upper surface 24 extends against the lower surface 14 of the first layer 8. The intermediate layer 12 is, for example, formed of a nonwoven fabric comprising PP fibers arranged to increase the compatibility of the first layer 8 and the second layer 10 during the assembly of the body 2. For this purpose, the intermediate layer 12 comprises, for example, interwoven PP fibers from the first group and the second group. Alternatively, the intermediate layer 12 is formed by a woven textile of natural fibers, which improves the mechanical characteristics of the filling element's body 2. Alternatively, the intermediate layer 12 is formed of a non-woven fabric comprising natural fibers and PP fibers, for example, from the first and second groups. The thickness of the intermediate layer 12 is, for example, approximately between 0.1 mm and 0.5 mm.
[0040] It is understood that the body 2 may comprise more than one intermediate layer 12.
[0041] The method for making the filling element 1 will now be described.
[0042] During a preliminary calibration step, the body 2 is calibrated, that is to say cut to dimensions corresponding to the dimensions of the filling element 1 to be produced. In the case of a body 2 made up of several layers, each layer is thus calibrated.
[0043] The body 2 is then placed in a thermoforming tool arranged to heat the body 2 and to give the body 2 the shape of the filling element 1. Such a tool is, for example, formed of two parts, each comprising a forming surface, one having the shape of the internal surface 4 of the filling element and the other of the external surface 6. The body 2 is placed between the two forming surfaces, which are brought close together so as to apply pressure and heating temperature to the body 2 in order to form the filling element 1. In the case of a body 2 comprising several layers, the layers are placed between the two parts of the tool, the first layer 8 extending from the side of the forming surface having the shape of the external surface 6 and the second layer 10 extending from the side of the forming surface having the shape of the internal surface 4.
[0044] The thermoforming tool is arranged to heat the body 2 to a temperature higher than the melting temperature of the PP fibers in the first and second groups. Thus, during the thermoforming of the body 2, the PP fibers in the first and second groups melt and form a matrix encapsulating the natural fibers. Due to the difference in melting point (IFC), the PP from the fibers in the first group flows towards the external surface 6 of the body 2, i.e., towards the forming surface of the thermoforming tool, which has the shape of the external surface 6 of the body 2. This is due to the difference in viscosities at iso-temperature, whereby the material with the lower viscosity flows more readily towards the heating surface.This flow can be promoted by heating the forming surface having the shape of the external surface to a different temperature, in particular above 180°C, than the heating temperature of the forming surface having the shape of the internal surface of body 2.
[0045] During the thermoforming step, the body 2 thus acquires the shape of the filling element 1 and comprises natural fibers encapsulated in PP made from fibers of the first and second groups. Furthermore, if the body 2 comprises several layers, these are assembled together by mixing the PP from the different layers.
[0046] The resulting body 2 comprises an upper layer 26 forming the external surface 6 of the filling element 1, in which the matrix encapsulating the natural fibers is formed primarily of PP derived from the PP fibers of the first group. "Primarily" means that at least 60% of the PP in the upper layer 26 is derived from the PP fibers of the first group. In one embodiment, particularly when the body 2 comprises a first layer 8 and a second layer 10, the PP in the upper layer 26 is entirely derived from the PP fibers of the first group. The upper layer 26 has, for example, a thickness of between 0.01 mm and 0.8 mm. In another embodiment, the upper layer 26 has a thickness equal to that of the first layer 8. The PP in the upper layer 26 forms a surface layer forming the external surface 6 of the body 2 and protecting the natural fibers extending into the rest of the body 2.This surface layer leaves the natural fibers visible through the outer surface 6 while protecting them from ultraviolet radiation and scratches. This protection is further enhanced when at least one additive is included with the PP fibers of the first group, as described previously. Indeed, this additive or these additives are then found in the upper layer 26 of the body 2, and particularly in the surface layer, so that they provide the outer surface 6 of the body 2 with the corresponding protective functions. Alternatively or in addition, the surface layer also allows the outer surface 6 of the body 2 to be colored. In other words, the functions usually performed by adding a PP film to a body to form a filling element are, according to the invention, performed by the surface layer of the body 2.
[0047] The resulting body 2 also comprises a lower layer 28 forming the inner surface 4 of the filling element 1, in which the matrix encapsulating the natural fibers is formed primarily of PP derived from the second group of PP fibers. By "primarily," it is understood that at least 60% of the PP in the lower layer 28 is derived from the second group of PP fibers. In one embodiment, particularly when the body 2 comprises a first layer 8 and a second layer 10, the PP in the lower layer 28 is entirely derived from the second group of PP fibers. The lower layer 28, for example, has a thickness greater than that of the upper layer 26 and is, for example, between 0.1 mm and 5 mm. In one embodiment, the lower layer 28 has a thickness equal to that of the second layer 10.
[0048] The filling element 1 described above is particularly simple and economical to produce because it does not require the addition of an extra film to form the external surface of the filling element.
Claims
Demands
1. Vehicle trim element (1) comprising a body (2) extending between an inner surface (4), intended to be turned towards a support of the trim element, and an outer surface (6), opposite the inner surface (4) and intended to be turned towards the passenger compartment of the vehicle, said body (2) being formed from at least one non-woven or woven material comprising natural fibers, a first group of polypropylene fibers having a first hot melt index and a second group of polypropylene fibers having a second hot melt index, lower than the first hot melt index, the polypropylene from the fibers of the first group extending mainly in an upper layer (26) of the body (2), said upper layer (26) forming the outer surface (6) of the body (2).
2. Filling element according to claim 1, wherein the first hot flow index is substantially between [30g - 80g] / 10 minutes.
3. Filling element according to claim 1 or 2, wherein the second hot flow index is substantially between [0.7g - 30g] / 10 minutes.
4. Filling element according to any one of claims 1 to 3, wherein the upper layer (26) has a thickness substantially between 0.01 mm and 0.8 mm.
5. Filling element according to any one of claims 1 to 4, wherein the propylene from the fibers of the second group extends mainly in a lower layer (28) of the body (2), said lower layer (28) forming the internal surface (4) of the body (2), the lower layer (28) having a thickness greater than the thickness of the upper layer (26).
6. Filling element according to any one of claims 1 to 5, wherein the natural fibres are selected from at least one of flax, hemp, kenaf and / or wood.
7. Filling element according to any one of claims 1 to 6, wherein the upper layer (28) of the body comprises at least one additive providing protection against ultraviolet radiation and / or against scratches to the external surface of the body and / or coloring to the external surface (6) of the body (2).
8. Method for making a trim element (1) according to one of any of claims 1 to 7, comprising the following steps: - supplying at least one body (2) formed of at least one layer of a non-woven or woven material comprising natural fibers, a first group of polypropylene fibers having a first hot melt index and a second group of polypropylene fibers having a second hot melt index, lower than the first hot melt index, - thermoforming said body (2) so as to give it the shape of the filling element to be produced, the heating temperature of the body (2) being arranged to cause the fusion of the polypropylene fibers of the first group and the second group, the propylene from the fibers of the first group flowing towards the external surface (6) of the body (2).
9. A method of embodiment according to claim 8, wherein the body (2) comprises a first layer (8) formed of a non-woven or woven material comprising natural fibers and the first group of polypropylene fibers and a second layer (10) formed of a non-woven or woven material comprising natural fibers and the second group of polypropylene fibers, the first layer (8) and the second layer (10) being thermoformed and assembled together during the thermoforming step of the body (2).
10. A method of embodiment according to claim 9, wherein the body (2) further comprises at least one intermediate layer (12) non-woven or woven, comprising natural fibers and / or polypropylene fibers, said intermediate layer (12) being disposed between the first layer (8) and the second layer (10) and being thermoformed and assembled with said first and second layers (8, 10) during the thermoforming step of the body (2).