Underbody trim components for road vehicles

Abstract

An underbody trim component for a road vehicle comprising a porous fibrous carrier layer, the trim component characterizing a longitudinal direction aligned with the direction of travel of the road vehicle when the component is in use, and further comprising an embossed foil locally bonded to the porous fibrous carrier layer, the bending stiffness of the embossed foil being at least 10% of the bending stiffness of the porous fibrous carrier layer, at least in the longitudinal direction. The trim component is particularly suitable for use as an underbody liner for a vehicle. However, the trim component may also be used as an under-engine liner or as a wheelhouse outer liner.

Description

[Technical field]

[0001] The present application relates to a trim member for a road vehicle. The trim member is particularly suitable for use in the underbody area of ​​the vehicle, for example as an underbody liner or as an under-engine liner. [Background technology]

[0002] For over 20 years now, road vehicle manufacturers have been equipping their products with exterior covering elements that cover the underside of the vehicle that faces the road. The main purpose of these elements is to improve the aerodynamics of the vehicle and thus reduce fuel consumption and CO2 emissions. To help improve the aerodynamics of the vehicle, these elements generally have a substantially planar shape.

[0003] In addition, it is essential that the mechanical properties of the material from which these components are made are such that they will maintain their shape when installed in the vehicle without exhibiting any significant deformation, in particular without exhibiting any significant sagging, and be sufficiently rigid to withstand the aerodynamic loads acting on them in use without damage or fracture over the entire life of the vehicle.

[0004] The mechanical properties of exterior trim members installed within the underbody area of ​​a vehicle can also be important for durability: Indeed, over the life of the vehicle, these members may be subject to environmental agents, stone chipping, and collisions with occasional road hazards, all of which they should be able to withstand without substantial degradation.

[0005] Traditionally, to achieve the desired mechanical properties, these components include substantially planar carriers, typically made of plastic materials manufactured by an injection molding process. However, these traditional solutions are heavy and, by adding weight to the vehicle, significantly negate the reduction in fuel consumption and CO2 emissions achieved by improving the vehicle aerodynamics as a result of installing these solutions on the vehicle.

[0006] During the last decade, lighter underbody trim components have appeared on the market. Plastic carriers have been replaced by lighter porous fibrous carriers. These components, being porous, are also known to have a favorable effect on the exterior noise emitted by the vehicle, and in particular on the noise emitted by the tires. However, these components struggle to obtain the required mechanical properties.

[0007] The solution used in the prior art to achieve the desired mechanical properties for these underbody trim components based on porous fibrous carriers consists in including in the fiber mix carrier-reinforcing inorganic fibers, such as glass or carbon fibers. However, the use of glass or carbon fibers can be problematic in that they pose a risk to the health of those who have to handle the component during its manufacture or for vehicle maintenance. Furthermore, the presence of glass in the fiber mix adversely affects the recyclability of the component at the end of its life and adds substantial weight to the component itself.

[0008] The solution customarily used in the prior art to achieve the desired mechanical properties for these underbody trim components based on a porous fibrous carrier consists in modifying the shape of the carrier by adding ribs and / or beads, which, however, adversely affects the aerodynamic properties of the vehicle in which the component is installed, for which a completely flat shape is preferred.

[0009] There is therefore a need for an underbody trim member that is substantially lighter than prior art underbody trim members based on plastic carriers, but at the same time features better mechanical properties than prior art underbody trim members based on porous fibrous carriers.It is an object of the present invention to provide such an underbody trim member. Summary of the Invention [Means for solving the problem]

[0010] The object of the present invention is achieved by an underbody trim part as defined in claim 1, by a method for manufacturing said trim part as defined in claim 18 and by a use of said trim part as defined in claim 19.

[0011] In particular, the object of the present invention is achieved by a trim member comprising a porous fibrous carrier layer, the trim member being configured to be installed as an underbody of a road vehicle and characterizing a longitudinal direction aligned with the direction of movement of the road vehicle when the member is in use, the trim member further comprising an embossed foil, the embossed foil being locally bonded to one side of the porous fibrous carrier layer, the bending stiffness of the embossed foil being at least 10% of the bending stiffness of the porous fibrous carrier layer, at least in the longitudinal direction. Effect of the Invention

[0012] A "layer" is a solid body made of one or more materials and filling the space between two closely spaced surfaces, the distance between which is substantially less than their size. The two surfaces are referred to as the "faces" of the layer, which are opposite each other. The distance between the two surfaces is called the thickness of the layer. This thickness may be variable.

[0013] A "porous fibrous carrier layer" is a layer that consists of one or more porous fibrous materials and that is capable of retaining its shape under the fixed load of its own gravity without undergoing any substantial deformation, independent of its orientation in space.

[0014] In a broad sense, the "bending stiffness" of a trim member and / or layer, specifically a porous fibrous carrier layer, describes its resistance to bending deformation. A typical mechanical load inducing bending deformation in a layer and / or in a part including the layer is a pressure applied to one of its faces, such mechanical load being hereinafter referred to as a "bending load". An example of a bending load is the pull-down pressure exerted by aerodynamic loads on a porous fibrous carrier layer of an underbody trim member covering the road-facing side of a road vehicle.

[0015] However, in materials engineering and in this application, "bending stiffness" more precisely refers to the case where a bending load is concentrated on a particular plane, where the direction perpendicular to this plane is called the "bending direction". Layers made of orthotropic materials and / or with mechanical properties that vary across their surface may have different bending stiffnesses in different bending directions.

[0016] Even more specifically, in the case of an underbody trim component for a road vehicle according to the invention, and in relation to the porous fibrous carrier layer and the embossed foil contained therein, bending stiffness hereinafter generally (unless otherwise specified) means the longitudinal direction, i.e. the direction that is intended to be aligned with the direction of movement of the road vehicle when the component is in use.

[0017]

[0018] Surprisingly, it has been found that by combining a porous fibrous carrier layer with a foil according to the present invention, i.e. a very thin, sheet-like layer made of a material which is itself very flexible in bending, the mechanical properties of the porous fibrous carrier layer can be improved, in particular its bending rigidity in the longitudinal direction.

[0019] Even more surprisingly, it has been found that increasing the bending stiffness even in the longitudinal direction alone improves the overall ability of the underbody trim member according to the present invention to withstand general bending loads compared to the ability of the porous fibrous carrier layer alone.

[0020] The analysis of the stiffening effect obtained by combining a porous fibrous carrier layer with a foil according to the invention has led to the realization that, surprisingly, the foil according to the invention can actually store a significant part of the total deformation energy of the trim member according to the invention when the trim member deforms under the action of bending loads acting on the porous fibrous carrier layer, by which the foil strongly participates in the ability of the member to resist bending loads and thus limits the deflection of the member itself compared to the porous fibrous carrier layer alone.

[0021]

[0022] In fact, in the trim element according to the invention, when the porous fibrous carrier layer is subjected to bending loads and deforms under the action of these, deformations are also induced in the foil, so that under bending loads the porous fibrous carrier layer and the foil according to the invention deform together as a whole. This occurs because in the trim element according to the invention, the foil is structurally bonded to the porous fibrous carrier layer. However, the structural bond does not concern the complete extent of the foil. On the contrary, the foil is only locally bonded to the porous fibrous carrier layer. Here, "locally bonded" means that the foil is not bonded to the porous fibrous carrier layer over its entire extent, but only at one or more corresponding points and / or in one or more corresponding areas.

[0023] In areas not bonded to the porous fibrous carrier layer, the foil according to the invention comprises one or more embossments, i.e. areas which are raised relative to the porous fibrous carrier layer and are not substantially in contact with the porous fibrous carrier layer.

[0024] The height of an "embossment" is the maximum distance between the surface of the embossment and the porous fibrous carrier layer. Similarly, the "size" of an embossment is intended to be the typical dimension of the area obtained by projecting the embossment onto the porous fibrous carrier layer, i.e. the "footprint" of the embossment on the porous fibrous carrier layer. As a typical dimension, the equivalent diameter of such an area can be considered.

[0025] In the trim element according to the invention, the function of the embossments is primarily to store deformation energy when the element is deformed under bending loads acting directly on the porous fibrous carrier layer. The embossments contained in the foil according to the invention are able to fulfill this function particularly effectively. In fact, embossments that are in a raised state, i.e. in a raised position relative to the porous fibrous carrier layer, deform more under bending loads than the latter layer. Due to the high level of bending stiffness of the embossed foil, this greater deformation leads to a higher stress level and thus a higher level of stored mechanical deformation energy.

[0026] The stiffening effect can be increased by increasing the total foil area raised relative to the porous fibrous carrier layer and / or by increasing the height of the embossments. For this purpose, in the case of a trim element according to the invention, it is preferred that the total area of ​​the foil raised relative to the porous fibrous carrier layer, i.e. the total embossed area of ​​the foil, is at least 20%, preferably at least 30% and more preferably at least 50% of the total area of ​​the foil.

[0027] For the same purpose, the height of the foil embossments in the trim member according to the invention is preferably at least 3 mm, more preferably at least 5 mm, and even more preferably at least 10 mm.

[0028] Surprisingly, test data show that a significant stiffening effect is obtained when the bending stiffness of the embossed foil, at least in the longitudinal direction, is at least 10% of the bending stiffness of the porous fibrous carrier layer. Thus, the desired stiffening effect can be obtained with an embossed foil whose inherent bending stiffness is significantly lower than that of the porous fibrous carrier layer. However, in order to further increase the stiffening effect, the bending stiffness of the embossed foil, at least in the longitudinal direction, is preferably at least 20%, even more preferably at least 40%, of the bending stiffness of the porous fibrous carrier layer.

[0029] Preferably, the embossed foil has a bending stiffness in the longitudinal direction of at least 0.05 N / mm, more preferably at least 0.15 mm.

[0030]

[0031] In areas not involved by the embossing, the embossing foil according to the invention preferably conforms to the shape of the porous fibrous carrier layer. In such areas, the embossing foil may be substantially in contact with the porous fibrous carrier layer without necessarily being bonded to the porous fibrous carrier layer. However, at least in some points and / or in some areas of such areas, the embossing foil according to the invention is bonded to the porous fibrous carrier layer. The bond between the areas and / or points of the embossing foil and the porous fibrous carrier layer can be obtained by common methods known in the art, i.e. by glue, and / or adhesive tape and / or adhesive film, and / or by welding (e.g. ultrasonic welding) and / or by thermal bonding processes.

[0032] In order to promote the desired stiffening effect, the foil is preferably bonded to the porous fibrous carrier layer over the entire area not involved by the embossing. However, and quite surprisingly, a remarkable stiffening effect can also be obtained if the embossed foil is bonded to the porous fibrous carrier layer over an area significantly smaller than the entire non-embossed area, i.e. the embossed foil is welded to the porous fibrous carrier layer only at a limited number of points distributed around its boundary.

[0033]

[0034] In an advantageous embodiment of the trim element according to the invention, the embossments are arranged in such a way that any planar cross section of the embossed foil cut perpendicular to the longitudinal direction is intersected by at least one embossment, with such an arrangement of embossments, a particularly pronounced increase in bending stiffness in the longitudinal direction is observed.

[0035] In a further preferred embodiment of the trim element according to the invention, the embossments are arranged in such a way that any planar cross section of the embossed foil intersects at least one embossment independently of its orientation, which makes it possible to further increase the overall bending stiffness of the trim element according to the invention, also for bending directions different from the longitudinal direction.

[0036] However, although this arrangement of the embossments has been found to be particularly advantageous, other different arrangements can be used without detracting from the overall stiffening effect obtained by the embossed foil according to the invention.

[0037]

[0038] The embossments contained in the embossing foil may be shaped in several different ways. For example, the embossments may be shaped like a right-angled or tapered parallelepiped, or more generally like a right-angled or tapered prism with a triangular or polygonal cross section. For a given height and a given size, the shape of the embossments may affect the mechanical performance of the trim member according to the invention.

[0039] In a preferred embodiment, the embossed foil comprises a number of embossments having the shape of a cross, the cross having arms of the same or different lengths. For a given height and size of the embossments, it has been observed that this embodiment has a higher bending stiffness than that obtained with other shapes, for example prisms with a hexagonal cross section.

[0040] The embossments contained within the embossing foil may all have the same shape or may have different shapes, depending on the needs dictated by the environment, e.g. packaging space.

[0041]

[0042] Surprisingly, the foil according to the invention can already be realized with an extremely thin and lightweight embossed foil. In the underbody trim member according to the invention, the embossed foil preferably has a thickness of 0.2 mm to 1.0 mm, more preferably 0.3 mm to 0.7 mm, and preferably a weight of 100 g / m 2 ~1000g / m 2 , more preferably 300 g / m 2 ~700g / m 2 This allows an increase in the stiffness of the trim element according to the invention compared to the porous fibrous carrier layer alone to be obtained with a correspondingly very limited increase in weight.

[0043] The areal weight of an embossed foil shall be measured on a substantially flat sample cut out of the foil. For the evaluation of the areal weight of an embossed foil, a sample of at least 100 cm2 shall be measured.2 The average should be determined for at least 10 samples covering the entire area of ​​the sample.

[0044]

[0045] The embossing foil contained in the trim member according to the invention is preferably made of a single material, which may be easier and cheaper to produce. Preferably, this material is a polyester or a polyolefin. More preferably, this material comprises at least one polymer or copolymer selected from the group consisting of polyester, such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), polyamide, such as polyamide 6 or polyamide 66, polyolefin, such as polyethylene (PE), polypropylene (PP), low density polyethylene (LDPE), linear low density polyethylene (LLDPE) or high density polyethylene (HDPE).

[0046] In another embodiment, the embossing foil may consist of two or more sub-layers, each of which consists of a different material. Preferably, the material used for each sub-layer has similar properties as described for the case where the embossing foil consists of a single material. The use of multiple layers for the embossing foil may be advantageous to increase the stability and / or robustness of the trim member according to the invention.

[0047] The above mentioned materials are only examples of possible materials to be used for the embossing foil, the embossing foil may also be realised by other materials known to those skilled in the art.

[0048]

[0049] To obtain the desired stiffening effect, the embossed foil may be partially bonded to either side of the porous fibrous carrier layer. However, in a preferred embodiment, the porous fibrous carrier layer comprises one side facing the vehicle and one side facing the road, and the embossed foil is partially bonded to the side facing the vehicle. This embodiment avoids the embossing of the foil from interfering with the air flow under the vehicle while the vehicle is in use, which improves the vehicle aerodynamics. This embodiment thus makes it possible to obtain an underbody trim member that features an optimal combination of mechanical stiffness and aerodynamics, without the need to modify the design of the porous fibrous carrier layer, for example by adding ribs, in a way that may be detrimental to the vehicle aerodynamics.

[0050] In a further preferred embodiment, the embossing foil is partially bonded to the side of the porous fibrous carrier layer intended to face the vehicle, and furthermore, the embossing foil comprises at least one embossment which cooperates with a part of said porous fibrous structure layer to form a substantially closed cavity. This embodiment is particularly advantageous in that the acoustic properties of the trim element according to the invention are quite surprisingly improved compared to those of the porous fibrous carrier layer alone, in particular with regard to the ability to absorb sound waves impinging on the porous fibrous carrier layer from the road-facing side. In this embodiment, the element according to the invention can thus help to reduce the external noise emitted by the vehicle, in particular tire noise.

[0051] In this particular embodiment, the embossed layer is partially bonded to the vehicle-facing side of the porous fibrous carrier layer, and the embossed layer comprises at least one embossment cooperating with a portion of said porous fibrous carrier layer to form a cavity, the walls of which consist of two members, a first member formed by the embossing and a second member formed by said portion of the porous fibrous carrier layer.

[0052] Surprisingly, sound waves impinging on this part of the porous fibrous carrier layer from the side intended to face the road can be absorbed to a significantly greater extent than if the porous fibrous carrier layer were considered as a standalone sound absorbing device, which is indeed very surprising, since this improvement can be achieved by combining the porous fibrous carrier layer with a foil which has little or no sound absorbing capacity by itself due to its very limited thickness.

[0053] Analysis of this acoustic effect shows that it can be seen to result from the coupling of vibrations of the portion of the porous fibrous carrier layer that cooperates with the embossing to form the cavity with an oscillating acoustic pressure inside the air volume of the cavity itself. If the acoustic wavelength is substantially larger than the size of the cavity, the acoustic pressure inside the cavity is essentially constant in space and varies over time with the frequency of the impinging sound wave. In these conditions, the cavity can act as an "acoustic spring". The acoustic spring is periodically compressed and relaxed, and exerts an oscillating pressure on the portion of the porous fibrous carrier layer that is in contact with the cavity. This portion of the porous fibrous carrier layer vibrates under the load of this pressure, acting as a "porous mass" and giving rise to an "acoustic spring-porous mass" system. This system can absorb the acoustic energy impinging on the system from the road-facing side of the porous fibrous carrier layer very efficiently, and in particular significantly more efficiently than the porous fibrous carrier layer alone. This is especially true in a certain frequency range that is determined by the geometry of the cavity and by the properties of the porous fibrous carrier layer, mainly its airflow resistance: indeed, the vibro-acoustic coupling between the cavity and the part of the porous fibrous carrier layer in contact with it depends to a large extent on this feature.

[0054] The above-mentioned "acoustic spring-porous mass" system, and thus the noise absorption properties of the trim member according to the invention, can be advantageously optimized by fine-tuning the geometry of the embossings and the physical properties of the porous fibrous carrier layer, in particular its airflow resistivity.

[0055] More specifically, the height and size of the embossments can be adjusted to obtain an optimal absorption action over a specific predetermined frequency range. For a fixed target frequency range, the size of the embossments cooperating with the portion of the porous fibrous carrier layer to form the cavities should be selected to be substantially smaller than, but of the same order of magnitude as, the acoustic wavelength over the target frequency range. Suggestively, the size of the embossments should be 1 / 10 to 1 / 2 the acoustic wavelength. In fact, cavities with dimensions smaller than 1 / 10 of the wavelength result in an acoustic spring that is "too stiff". The benefits of the acoustic spring are limited to frequencies above the target frequency range. Moreover, if the cavity is too small, the acoustic spring will still be inefficient due to the small amount of air contained within the spring. Vice versa, cavities with dimensions larger than half the wavelength result in an acoustic spring that is "too soft". The benefits of the acoustic spring are limited to frequencies below the target frequency range.

[0056] In addition, the greater the height of the embossing that cooperates with a portion of the porous fibrous carrier layer to form a cavity, the taller the cavity will be and the lower the frequency range in which the "acoustic spring-porous mass" system formed by this cavity and the portion of the porous fibrous carrier layer in contact with this system will optimally absorb noise.

[0057] The embossments may all have the same height and / or size, or may have different heights and / or sizes. The differences in height and / or size of the embossments may be dictated by packaging space constraints. However, these differences may also be purposefully designed, for example to obtain a broader band sound absorption and / or to obtain optimal sound absorption at different frequency ranges for different areas of the trim member.

[0058] Furthermore, the airflow resistivity (AFR) of the portion of the porous fibrous carrier layer that cooperates with the embossing to form the cavity influences the frequency range in which the noise absorption of the corresponding "acoustic spring-porous mass" system is optimal and can be adjusted to adjust this as desired. In particular, the higher the airflow resistivity, the lower this frequency range. However, an excessively high airflow resistivity can be strongly detrimental to the absorption of the trim member at high frequencies.

[0059] For trim members according to the invention, the embossments preferably have a height of 3 mm to 50 mm, more preferably 7 mm to 30 mm, and even more preferably 10 mm to 25 mm.

[0060] Furthermore, the size of the embossed portion is preferably 20 mm to 200 mm, more preferably 30 mm to 150 mm, and even more preferably 40 mm to 100 mm.

[0061] In the case of the trim member according to the invention, the porous fibrous carrier layer preferably has a resistance of 100 Ns / m 3 ~3500Ns / m 3 , more preferably 200Ns / m 3 ~2000Ns / m 3 , and even more preferably 300Ns / m 3 ~1300Ns / m 3 Air flow resistivity is measured in accordance with ISO 9053-1:2018.

[0062] Testing has shown that the above-mentioned ranges for embossment height and size, and the above-mentioned ranges for the airflow resistivity of the porous fibrous carrier layer, especially in combination, are particularly suitable for obtaining optimal absorption performance within the frequency range of 800Hz to 1400Hz, which is known to be most relevant for tire noise.

[0063] In the trim element according to the invention, the embossing foil preferably does not contain only one embossing portion, but several embossing portions each cooperating with the porous fibrous carrier layer to form a cavity, whereby several cavities are formed between the embossing foil and the porous fibrous carrier layer on the side of the porous fibrous carrier layer intended to face the vehicle. The greater the total surface of the part of the porous fibrous carrier layer which cooperates with the embossing portion to form a cavity on the side opposite to the side facing the noise source, the greater the improvement in sound absorption obtained by the trim element according to the invention compared to the porous fibrous carrier layer alone. Preferably, said total surface is at least 20%, more preferably at least 30%, even more preferably 50% of the total surface of the side of the porous fibrous carrier layer intended to face the vehicle.

[0064]

[0065] The porous fibrous carrier layer preferably comprises one or more fibrous materials.

[0066] In one embodiment, the porous fibrous carrier layer comprises thermoplastic bicomponent filaments. Filaments are continuous fibers having an infinite length. Filaments are also known as endless filaments or continuous filaments.

[0067] Bicomponent filaments are synthetic fibers formed from two polymers of different chemical and / or physical structure, a first polymer and a second polymer. These polymers are intimately but separably bound to each other. Bicomponent filaments may be produced using processes known to those skilled in the art, for example by melt spinning. In this process, the polymers are spun by a spinneret into fibers that are side-by-side, or around each other (core-sheath), or as a mixture with a heterogeneous distribution (island-in-the-sea or segmented pie). In addition, the filaments can have different cross sections, preferably the filaments used have a circular or trilobal cross section. In the case of bicomponent filaments, the melting point of the second polymer is lower than that of the first polymer, so that when the bicomponent fiber is heated, the first and second polymers react differently. When a bicomponent filament is heated to a temperature above the softening or melting point of the second polymer (e.g., the sheath polymer in a sheath-core configuration) and below the melting point of the first polymer (e.g., the core polymer in a sheath-core configuration), the second polymer softens or melts while the first polymer does not. The softening of the second polymer makes it tacky and bonds to any filaments that may be in close proximity. At the same time, the melting of the second polymer causes the formation of droplets that pin adjacent fibers at their intersections while the first polymer remains intact, forming a filament network in the final product.

[0068] Starting with a nonwoven fibrous porous mat containing bicomponent filaments, it is possible to obtain a consolidated porous fibrous carrier layer having structural properties due to the network of endless filaments contained therein, by compressing it while heating it at a temperature above the softening or melting temperature of the second polymer but below the softening or melting temperature of the first polymer, which are continuous, can span a large area, and are held together by a plurality of randomly distributed contact points.

[0069] Preferably, the filament diameter is between 14 microns and 37 microns, more preferably between 20 microns and 25 microns for increased strength.

[0070] In a preferred embodiment, the porous fibrous carrier layer is made of polyester bicomponent filaments. A porous fibrous carrier layer made entirely of polyester may make it easier to recycle production cuttings and / or to recycle the porous fibrous carrier layer as a whole at the end of the product life. In this preferred embodiment, the first polymer is preferably polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), and the second polymer is a copolymer of polyethylene terephthalate (coPET) or a copolymer of polybutylene terephthalate (coPBT).

[0071] In this embodiment, at least a portion of the polyester may advantageously have recycled properties. For example, the PET used as the first polymer can be obtained from consumer products such as PET bottle flakes, or from PET packaging articles, or from PET marine products such as fishing nets, by melting them and forming them into pellets that can be used for the spinning process. The advantage of using recycled polyester is to reduce the environmental impact of the manufacturing process of the underbody trim member according to the invention, specifically its CO2 footprint. In this embodiment, preferably at least 20%, more preferably at least 50%, and even more preferably at least 70% of the polyester used for the bicomponent fiber is recycled polyester. The percentages are weight percentages calculated based on the total weight of the porous fibrous carrier layer.

[0072]

[0073] In another embodiment, the porous fibrous carrier layer comprises a mixture of staple fibers and a binder. The staple fibers are cross-wrapped and needled, and the binder is thermoplastic or thermosetting. When a thermoplastic binder is used, it is preferably in the form of a thermoplastic bicomponent staple fiber, preferably made of polyester, polyamide, or polypropylene. When a thermosetting binder is used, it is preferably in the form of a resin, preferably an epoxy resin or a phenolic resin. Staple fibers, unlike filaments, are provided in discrete, predetermined lengths, typically obtained by cutting endless filaments after their production.

[0074] In this embodiment, the staple fibres are preferably organic fibres such as cotton, kenaf, hemp, or synthetic thermoplastic fibres such as polyester, preferably PET or PBT, or polyamide, preferably polyamide-6 or polyamide-66, or polyolefins, preferably polypropylene, polyethylene, or inert fibres, preferably glass fibres, carbon fibres, or ceramic fibres, or mixtures thereof.

[0075] The staple fibers may be virgin fibers, or may have at least partially regenerated or recycled origin, or may be formed using at least partially recycled content.

[0076] Preferably, the staple fibres have a diameter of between 14 microns and 37 microns, more preferably between 20 microns and 25 microns for increased strength.

[0077] Quite surprisingly, starting from a nonwoven porous fibrous mat comprising a mixture of staple fibers and binder, the staple fibers being cross-wrapped and needled, it is possible to compress it under heating, giving structural properties to the resulting layer, and to obtain a porous fibrous carrier layer. This is due to the combined effect of the binder and the needling of the staple fibers, which improves the mechanical properties of the layer resulting from the process. On the one hand, the binder creates multiple discrete bonding points between adjacent staple fibers during the process. On the other hand, the needling causes the fibers to intertwine with each other. The combination of these two effects results in a strong fiber network, despite the limited length of the fibers.

[0078] If the binder is in the form of a thermoplastic bicomponent staple fiber, the temperature used during molding should be sufficient to soften or melt the low melting temperature polymer contained in the binder fiber, but still below the softening or melting temperature of the high melting temperature polymer contained in the binder fiber. If the binder is in the form of a thermosetting resin, the temperature used during molding must be high enough to cure the resin, resulting in crosslinking of its polymer chains.

[0079] In a preferred embodiment, both the staple fibers and the binder are polyester bicomponent fibers. The first polymer is preferably PET or PBT, and the second polymer is preferably a copolymer of PET or a copolymer of PBT, the softening or melting temperature of the low melting polymer of the binder fibers being lower than that of the low melting polymer of the staple fibers. In this way, a porous fibrous carrier layer consisting entirely of polyester is obtained, which is advantageous from the viewpoint of recycling. A porous fibrous carrier layer consisting entirely of polyester may make it easier to recycle production cuttings and / or to recycle the porous fibrous carrier layer as a whole at the end of the product life.

[0080] In this embodiment, it may be advantageous for at least a portion of the polyester to have recycled properties, preferably at least 20%, more preferably at least 50%, and even more preferably 70%. The percentages are weight percentages calculated with respect to the total weight of the porous fibrous structure layer. The advantage of using recycled polyester is that it reduces the environmental impact of the manufacturing process of the underbody trim member according to the invention, in particular its CO2 footprint.

[0081] In another preferred embodiment, the staple fibers are inorganic fibers, in particular glass fibers, carbon fibers, or a mixture thereof, and the thermoplastic binder consists of a polyamide, preferably polyamide 6 or polyamide 66, or a polyolefin, preferably polypropylene. The use of inorganic fibers, such as glass fibers or carbon fibers, can further improve the structural rigidity (in particular the bending rigidity) and can also improve the dimensional stability and shape definition of the porous fibrous carrier layer.

[0082] In this embodiment, the amount of inorganic fibers is preferably between 20% and 80% by weight, more preferably between 30% and 70% by weight, and even more preferably between 40% and 60% by weight, the percentages being weight percents calculated relative to the total weight of the porous fibrous carrier layer.

[0083]

[0084] The material used for the porous fibrous carrier layer preferably has the same chemical family as the material used for the embossing foil, which allows recycling of the finished trim member according to the invention at the end of its life. Even more preferably, both the porous fibrous carrier layer and the embossing foil consist of materials belonging to the polyester family.

[0085]

[0086] The areal weight of the porous fibrous carrier layer is determined to a large extent by design and functional constraints. An excessively high areal weight is obviously undesirable, since this increases the overall vehicle weight and increases fuel consumption and CO2 production. At the same time, an excessively low areal weight may be problematic with respect to important functional performance, e.g. stone chipping. In the component according to the invention, the areal weight of the porous fibrous carrier layer is preferably 600 g / m 2 ~2500g / m 2 , more preferably 800 g / m 2 ~1700g / m 2 , and more preferably 900 g / m 2 ~1400g / m 2 It is.

[0087]

[0088] The greater the thickness of the porous fibrous carrier layer, the higher the absorption of the trim element according to the invention, particularly at high frequencies. At the same time, however, an excessively large thickness is undesirable for reasons of packaging space and may be detrimental to the bending stiffness of the porous fibrous carrier layer, since the fibrous material may become too high and too soft with increasing thickness. Preferably, the thickness of the porous fibrous carrier layer contained in the trim element according to the invention is between 1 mm and 10 mm, more preferably between 2 mm and 7 mm.

[0089] The higher the bending stiffness of the porous fibrous carrier layer, the higher the bending stiffness of the trim part according to the invention. Preferably, the bending stiffness of the porous fibrous carrier layer is more than 0.2 N / mm, more preferably more than 0.35 N / mm, even more preferably more than 0.6 N / mm, independent of the possible bending direction.

[0090]

[0091] To improve the acoustic properties of the underbody trim member according to the invention, a thin fibrous porous layer (commonly known in the art as a "scrim") or a micro-perforated polymer foil having a tailored airflow resistivity can be laminated to at least a portion of one side of the porous fibrous carrier layer, preferably the side intended to face the road. The airflow resistivity of the fibrous scrim or micro-perforated polymer foil is preferably higher than that of the porous fibrous carrier layer, more preferably at least 20% higher than that of the porous fibrous carrier layer, in all areas where the fibrous scrim or micro-perforated polymer foil is applied.

[0092] In this embodiment, the areal weight of the fibrous scrim or microporous polymer foil is preferably less than 400 g / m2 so as not to substantially increase the total weight of the underbody trim member according to the present invention. 2 Less than 200 g / m 2 The following is the result.

[0093] Preferably, the additional fibrous scrim or microporous polymer foil is made of a material belonging to the same chemical family as the material constituting the porous fibrous carrier layer, in order to facilitate recycling.

[0094] In order to always further improve the sound absorbing action, the trim element according to the invention may comprise one or more additional sound absorbing devices arranged on the side of the porous fibrous carrier layer, preferably on the side intended to face the vehicle. The additional sound absorbing devices may comprise any type of sound absorbing material known to the person skilled in the art, for example fibrous materials, such as textile nonwovens or felts or cellular materials, such as open cell foams, in particular polyurethane foams.

[0095] The additional sound-absorbing device may be in the form of a layer comprising one or more sound-absorbing materials. In this case, such an additional sound-absorbing device may be laminated together with the porous fibrous carrier layer and may be structurally connected to it by gluing and / or stapling and / or by welding (e.g. ultrasonic welding), and thus may also participate in further increasing the structural rigidity of the trim element according to the invention, in particular its bending rigidity. Such an additional sound-absorbing device may completely or partially cover the side of the porous fibrous carrier layer on which it is applied.

[0096] The additional sound-absorbing device may be in the form of a block of sound-absorbing material, where a "block" is a body having no dimensions substantially smaller than the other dimensions, in which case the additional sound-absorbing device may be arranged and / or adhesively bonded to one side of the porous fibrous carrier layer and is preferably accommodated in accordance with the recesses and / or in accordance with the irregularities of the porous fibrous carrier layer itself.

[0097] All the above mentioned measures for improving the sound absorbing action of the underbody trim member according to the invention, i.e. the addition of scrims and / or perforated foils and / or additional absorbing devices, may be combined as technically possible and as known to the person skilled in the art, for example a perforated polymer foil may be laminated to at least a portion of one side of a porous fibrous carrier layer and a further layer of sound absorbing material may be added on top of the perforated foil.

[0098]

[0099] The trim member according to the invention may be manufactured using methods known to those skilled in the art, in particular the porous fibrous carrier layer and the embossing foil may be manufactured separately and then locally bonded to each other in a subsequent step.

[0100] The porous fibrous carrier layer may be produced, for example, by compressing, molding and consolidating a porous fibrous nonwoven mat under heat. The embossed foil may be produced, for example, by vacuum forming or by injection molding. Finally, the porous fibrous carrier layer and the layer with the embossing may be locally bonded to one another by methods known to those skilled in the art, for example by gluing and / or by ultrasonic welding.

[0101] As far as the measurement of the bending stiffness is concerned, the ISO-178:2019 standard was followed, which describes the "three-point bending" test for measuring the bending stiffness of beam-shaped specimens. This standard is adapted to express the bending stiffness which is indicative of the bending behavior of the component according to the invention in the longitudinal direction. In comparison with the ISO standard, the size of the test specimen, the size and position of the support, the size and position of the indenter were adapted as shown in the examples below. In general, a specimen with a length of 420 mm was cut from the trim component in its longitudinal direction. The specimen is preferably cut from the central region in the longitudinal direction of the component. However, the specimen may also be cut from a region close to the longitudinal end of the component. In case the length of the component in the longitudinal direction is less than 500 mm, the entire component may be used as the test specimen. In any case, it is necessary that the specimen extends over the entire width of the component and Care should be taken so that the specimen contains as many embossments as possible in both directions. The supports and the indenter have the same size of 130 mm, they are aligned in the longitudinal direction of the specimen, and they are centered in the transverse direction, i.e. perpendicular to the longitudinal direction on a horizontal plane. The distance between the supports is 340 mm and the indenter is positioned in the central plane between the supports. Starting from an initial preload of 0.1 N, the force is gradually increased to obtain a controlled displacement of the indenter of 100 mm / min. The applied force and the corresponding displacement of the indenter are recorded in a force-displacement curve. A straight line is calculated by linear regression in the linear elastic part of the curve. The slope of this line, expressed in N / mm, represents the average ratio of force to displacement in the linear region of the force-displacement curve, which gives the bending stiffness of the specimen in the direction parallel to the length of the member.

[0102] All ranges provided throughout this specification are intended to include the beginning and end points, as well as the normal expected deviation in measurements. The beginning and end points of the various ranges may be combined.

[0103] Further embodiments of the invention emerge from the description, both by combining different embodiments and examples of the invention and also from the description of the embodiments shown in the drawings, which are schematic and not necessarily drawn to scale. [Brief description of the drawings]

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[0113] [Figure 1] FIG. 1 is a diagram showing an embodiment of an underbody trim member according to the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the underbody trim member shown in FIG. [Diagram 3] 3a and 3b are perspective and top views, respectively, of another trim member according to the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing the trim member of FIGS. 3a-3b. [Diagram 5] FIG. 5 illustrates another embodiment of an underbody trim member according to the present invention. [Figure 6]6a and 6b are side and perspective views, respectively, of the test setup used to measure bending stiffness. [Figure 7] FIG. 7 shows the force-displacement curve obtained from a bending stiffness test carried out on a specimen extracted from a component according to the invention, together with the straight line obtained from this test by linear regression in the linear elastic range corresponding to a displacement range of 10 mm to 14 mm. [Figure 8] FIG. 8 shows the same force-displacement curve as shown in FIG. 7 obtained from a bending stiffness test carried out on a sample extracted from a component according to the invention, together with similar curves obtained from similar tests carried out on the porous fibrous carrier layer alone and on the embossed foil alone. [Figure 9] FIG. 9 shows the sound absorption coefficient measured in the Alpha Cabin for a component according to the invention compared to a porous fibrous carrier layer alone. [Figure 10] FIG. 10 shows two underbody trim components according to the present invention, in which the porous fibrous carrier layer has a 3D shape. [Figure 11] FIG. 11 shows two underbody trim components according to the present invention, in which the porous fibrous carrier layer has a 3D shape. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0114] FIG. 1 shows an embodiment of an underbody trim part (10) according to the invention. The part comprises a porous fibrous carrier layer (1) and an embossing foil (2). The embossings (3)-(4) represent areas where the foil is in raised relation to the porous fibrous carrier layer (1), i.e. three-dimensional elements raised from a substantially planar base. Some embossings (3) cooperate with the porous fibrous carrier layer (1) to form closed cavities, whereas for some other embossings (4) this is not the case. Corresponding to all areas not involved by embossings (5), the embossing foil (2) conforms to the shape of the porous fibrous carrier layer (1) and, in this embodiment, is bonded to the porous fibrous carrier layer. Moreover, in this embodiment, all embossings (3) which cooperate with the porous fibrous carrier layer (1) to form closed cavities are cross-shaped. The element according to the invention shown in Figure 1 is essentially rectangular in shape, with one dimension substantially larger than the other, and is adapted to be placed under a lateral section of the main floor of a road vehicle, with its longitudinal direction, i.e. the direction which should be aligned with the direction of movement when the element is in use, aligned with its longer dimension, i.e. its length.

[0115] Figure 2 shows a cross section A-A' of the trim member according to the invention shown in Figure 1. As this cross section shows, the porous fibrous carrier layer may follow the shape of the embossed foil (2) in some non-flat areas (6), whereas in some other areas (7) this may not be the case.

[0116] Figures 3a and 3b respectively show a perspective view and a top view of another underbody trim element according to the invention. Like the underbody trim element shown in Figure 1, this element is also essentially rectangular in shape and is designed to be placed under a lateral section of the main floor of a road vehicle. Its longitudinal direction, i.e. the direction of movement when the element is in use on a road vehicle, is aligned with its longer dimension, i.e. its length. However, unlike the trim element shown in Figure 1, in the case of the trim element shown in Figures 3a-3b the porous fibrous carrier layer is flat and all embossments (3) cooperate with the porous fibrous carrier layer (1) to form closed cavities. Furthermore, in the trim element shown in Figures 3a-3b the embossed foil (2) is partially joined to the porous fibrous carrier layer by ultrasonic welding according to the welding scheme shown in Figure 3b. The black dots (8) indicate the positions of the welding points.

[0117] From the top view shown in figure 3b it is also clear that in the underbody trim part according to the invention shown in figures 3a-3b the embossings (3) are arranged in such a way that any plane section of the embossing foil (2) cut perpendicular to the longitudinal direction intersects at least one embossing. By way of example only, figure 4 shows a cross section AA' of the embossing foil obtained by cutting the embossing foil according to the plane shown in figure 3b. As can be seen, this cross section actually intersects several embossings (3) contained in the embossing foil. The same result is obtained with any cross section cut parallel to the cross section AA'.

[0118] As can always be seen from the top view shown in figure 3b, any planar section through the embossed foil, independent of its orientation, intersects at least one embossment. With this type of arrangement of embossments, the desired stiffening effect, as mentioned above, is particularly evident not only in the longitudinal direction of the part.

[0119] Figure 5 shows another embodiment of a trim element (10) according to the invention. It differs from the one shown in Figure 3a in terms of the fact that the embossments (3) have different shapes and sizes and are not arranged according to a regular pattern. However, as in the case of the trim element shown in Figure 3a, in this case too the embossments are arranged in such a way that any planar cross section of the embossing foil (2) perpendicular to the direction of the length of the element is intersected by at least one embossment.

[0120] A first example trim member according to the present invention and based on the construction shown in Figures 3a-3b was manufactured as follows: A nonwoven porous fibrous mat consisting of 100% PET bicomponent filaments was compressed and consolidated under heat to an areal weight of 1031 g / m2. 2 A flat porous fibrous carrier layer was achieved with a width of 400 mm, a length of 1220 mm, and a thickness of 4.3 mm. The airflow resistivity of the porous fibrous carrier layer was measured according to ISO 9053-1:2018 and was found to be 336 Ns / m 3 3a。This value is the average of the values ​​obtained at 10 points distributed over the surface of the porous fibrous carrier layer. The embossed foil, consisting of a single layer of A-PET (amorphous PET) with a thickness of 0.45 mm, exhibiting embossments shaped as crosses with arms of equal length and arranged in the regular pattern shown in FIG. 3a, was realized by vacuum forming. The height of the embossments is 15 mm, and their size is 58 mm. The embossed foil (2) was joined to the porous fibrous carrier layer (1) in a discrete set of points by ultrasonic welding according to the welding scheme shown in FIG. 3b. The black dots (8) indicate the positions of the weld points.

[0121] The bending stiffness of a trim member of a first embodiment according to the invention in a direction parallel to its length (corresponding to its longitudinal direction) was measured according to the method described above. In detail, a rectangular test specimen was extracted from the central area of ​​the member, with the same width as the member (400 mm) and a length of 420 mm. The specimen is shown in Figures 6a and 6b together with the setup used for measuring the bending stiffness in the longitudinal direction. Figure 6a shows a side view of the test setup, whereas Figure 6b shows a top perspective view. The size of the specimen corresponds to approximately one third of the size of the member, which is intended to represent the bending behavior of the member in a direction parallel to its length, since it occupies the entire width of the member and includes several embossments in both directions. For the test, the specimen was placed on two rigid supports (20) with a length of 130 mm (i.e. approximately one third of the width of the specimen). The supports were positioned at a distance of 340 mm from each other (i.e. approximately four fifths of the length of the specimen). The supports were centered in the width direction relative to the specimen. A vertical force is applied by a linear stiffness indenter (21) having the same length as the supports. The indenter is arranged parallel to the support itself (20) and positioned exactly in the middle between the two supports. Starting from an initial preload of 0.1 N, the force is gradually increased so as to obtain a controlled displacement of the indenter of 100 mm / min. By recording the applied force and the corresponding displacement of the indenter, a force-displacement curve (30) is obtained, such as the dashed and dotted line shown in FIG. 7. A straight line (31) is then calculated by linear regression in the linear elastic part of the curve, for example in the displacement range of 10 mm to 14 mm in the case illustrated in FIG. 7. This straight line (31) is shown in FIG. 6 as a solid line in the displacement range of 10 mm to 14 mm. The slope of this line, expressed in N / mm, represents the average ratio of force to displacement in the linear region of the force-displacement curve, which gives the bending stiffness of the sample in the direction parallel to the length of the member.

[0122] Similar tests were repeated on samples of the porous fibrous carrier layer alone, having the same dimensions as those mentioned above, following a procedure completely similar to that described above for the sample extracted from the trim part according to the invention. Figure 8 shows the force-displacement curves obtained for the porous fibrous carrier alone and for the sample extracted from the part according to the invention. Thus, the dashed and dotted line (30) shown in Figure 8 is the same as that shown in Figure 7, which corresponds to the sample obtained from the part according to the invention, whereas the dotted line (32) shown in Figure 8 corresponds to the porous fibrous carrier alone. The significantly higher slope of the dashed and dotted line (30) compared to the slope of the dotted line (32) indicates that the sample obtained from the part according to the invention has a significantly higher bending stiffness than the porous fibrous carrier alone. Thus, from the force-displacement curves (30) and (32) it was calculated that the bending stiffness of the porous fibrous carrier layer alone was 0.86 N / mm, whereas the bending stiffness of the sample extracted from the component according to the invention was 1.55 N / mm, i.e. 80% higher than that of the porous fibrous carrier layer alone, which is a very impressive increase in bending stiffness.

[0123] A second embodiment of the trim part according to the invention was realized, which differed from the first part only with respect to the number of welds used to bond the embossed foil to the porous fibrous carrier layer. That is to say, in the case of this second trim part, of all the welds (8) shown in FIG. 3b, only those distributed around the border of the embossed foil (2) were kept. The number of welds for this second trim part according to the invention is thus significantly reduced compared to that of the first trim part according to the invention described above. Following the same procedure as described for the first part, the bending stiffness of this second trim part in the direction parallel to the length was measured, which resulted in 1.41 N / mm, which is only 9% lower than that of the first part, but still about 67% higher than that of the porous fibrous carrier alone. This shows, quite surprisingly, that a large stiffening effect can be obtained by bonding the embossed foil according to the invention to the porous fibrous carrier layer, practically only minimally around the border.

[0124] In order to understand the intrinsic level of bending stiffness of the embossed foil required to achieve such a significant stiffening effect, the bending stiffness of a sample consisting of the foil alone was measured, following exactly the same procedure as described above for the sample extracted from the component according to the invention. The force-displacement curve (33) obtained for the embossed foil sample is shown as a solid line in FIG. 8. The bending stiffness of the embossed foil was then calculated from this curve and found to be 0.18 N / mm, i.e. only about 21% of the bending stiffness of the porous fibrous carrier alone. This shows that the bending stiffness of the porous fibrous carrier layer can be surprisingly improved by 70% to 80% by applying to the porous fibrous carrier layer an embossed foil having an intrinsic bending stiffness of only slightly more than 20% of the bending stiffness of the porous fibrous carrier layer itself. This also means that the achieved increase in bending stiffness is not due to a simple addition of the bending stiffness values ​​of the porous fibrous carrier layer and the embossed foil, but is based on a synergistic effect that arises between the porous fibrous carrier layer and the embossed foil, even though they are only minimally bonded to each other.

[0125] A third example trim part according to the invention was produced, which differs from the first trim part according to the invention only with respect to the thickness of the porous fibrous carrier layer, in this case 2.3 mm. Following the same procedure as previously described, the bending stiffness of this third trim part according to the invention and of the porous fibrous carrier layer contained therein was measured, which resulted in 1.15 N / mm and 0.43 N / mm, respectively. Thus, for this third part according to the invention, the bending stiffness in the longitudinal direction of the foil is about 42% of the bending stiffness in the same direction of the porous fibrous carrier layer, resulting in an increase in bending stiffness of more than 150%.

[0126] The sound absorption of the trim part of the first embodiment according to the invention was measured by the Alpha Cabin measuring system customarily used in the automotive sector for absorption tests on sound absorbing trim parts. The trim part according to the invention was tested by placing it on the floor of the Alpha Cabin with the porous fibrous carrier layer facing up, i.e. exposed to the noise source. A comparative test was carried out with the porous fibrous carrier layer alone. During the test, a gap of 15 mm was left between this layer and the floor of the Alpha Cabin. The dashed and dotted line (50) in FIG. 9 shows the absorption coefficient of the trim part according to the invention, whereas the dotted line (51) in the same FIG. 9 shows the absorption coefficient of the porous fibrous carrier layer alone. As can be seen, the trim part according to the invention has a significantly better absorption effect than the porous fibrous carrier layer alone, in particular within the frequency range of 800 Hz to 1600 Hz, which is known to be highly relevant for tire noise.

[0127] FIG. 10 shows a trim element according to the invention, in which the porous fibrous carrier layer (1) has a 3d shape and the embossing foil (2) contains embossments similar to those of the embossing of the trim element shown in FIG. 3a, i.e. embossments having the shape of a cross with arms of the same length. The embossments are arranged mostly according to a regular pattern, even if for reasons of packaging space they do not cover some areas of the porous fibrous carrier layer (1). The element is made to be installed in the underbody area of ​​a road vehicle and this characterizes the longitudinal direction indicated by the arrow "L" in FIG. 10. The longitudinal direction is intended to coincide with the direction of movement of the road vehicle when the element is in use. In this element too, the embossments are arranged in such a way that any planar cross section of the embossing foil intersects at least one embossment. This embossing results in a very significant increase in the bending stiffness of the element, both in the longitudinal direction and in any other direction.

[0128] FIG. 11 shows another trim element according to the invention. The porous fibrous carrier layer (1) has a 3d shape. However, in this case the embossments (3) are not cross-shaped. Instead they are in the form of rectangular prisms with rounded edges. The rectangular prisms are aligned in the longitudinal direction, indicated in FIG. 11 by the arrow "L". The embossments are offset in the longitudinal direction such that any planar cross section of the embossing foil (2) cut perpendicular to the longitudinal direction intersects with at least one embossment. The embossments, as already explained, result in a particularly significant increase in the bending stiffness in this same direction compared to the porous fibrous carrier (1) alone.

Claims

1. 1. A trim element configured to be installed as an underbody of a road vehicle, the trim element comprising a porous fibrous carrier layer and characterized in that its longitudinal direction is aligned with the direction of travel of the road vehicle when the element is in use, comprising:

1. A trim member, comprising: an embossed foil locally bonded to one side of the porous fibrous carrier layer; and wherein the embossed foil has a bending stiffness that is at least 10% of the bending stiffness of the porous fibrous carrier layer, at least in the longitudinal direction.

2. 2. A trim element according to claim 1, wherein the bending stiffness of the embossing foil is at least 20%, preferably at least 40%, of the bending stiffness of the porous fibrous carrier layer, at least in the longitudinal direction.

3. 2. A trim member according to claim 1, wherein the embossing foil has a bending stiffness in the longitudinal direction of at least 0.05 N / mm, preferably at least 0.15 N / mm.

4. 2. The trim member of claim 1, wherein any planar cross section of the embossing foil taken perpendicular to the longitudinal direction intersects with at least one embossment.

5. 2. The trim member of claim 1, wherein any planar cross section of the embossing foil intersects at least one embossment.

6. 2. A trim member according to claim 1, wherein the total area of ​​the embossings contained within the embossing foil is at least 20%, preferably at least 30%, more preferably at least 50% of the total area of ​​the embossing foil.

7. 2. A trim member according to claim 1, wherein the height of the embossments contained in the embossing foil is between 3 mm and 50 mm, preferably between 7 mm and 30 mm, more preferably between 10 mm and 25 mm.

8. 2. The trim member of claim 1, wherein at least one embossment has at least one shape between a right-angled or tapered parallelepiped, a right-angled or tapered prism with a triangular or polygonal cross section, preferably a hexagonal cross section, a cross with arms of the same or different lengths.

9. 2. A trim member according to claim 1, wherein the thickness of the embossing foil is between 0.2 mm and 1.0 mm, preferably between 0.3 mm and 0.7 mm.

10. The area weight of the embossed foil is 100 g / m ２ ~1000g / m ２ , preferably 300 g / m ２ ~700g / m ２ The trim member of claim 1 , wherein:

11. 2. The trim member according to claim 1, wherein the foil comprises at least one polymer or copolymer selected from the group consisting of polyester, preferably polyethylene terephthalate (PET), more preferably amorphous PET or polybutylene terephthalate (PBT), polyamide, preferably polyamide 6 or polyamide 66, polyolefin, preferably polypropylene (PP), polyethylene (PE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), or high density polyethylene (HDPE).

12. 2. The trim member of claim 1, wherein the porous fibrous carrier layer includes one side facing the vehicle and one side facing the roadway, and the side to which the embossed foil is partially bonded is the side facing the vehicle.

13. 13. A trim member according to claim 12, wherein at least one of the embossments contained in the embossing foil cooperates with the porous fibrous carrier layer to form a closed cavity.

14. The airflow resistivity of the porous fibrous carrier layer is 100 Ns / m ３ ~3500 Ns / m ３ , preferably 200 Ns / m ３ ~2000 Ns / m ３ , more preferably 300 Ns / m ３ ~1300 Ns / m ３ 13. The trim member of claim 12, wherein the airflow resistivity is measured in accordance with ISO 9053-1:2018.

15. 2. The trim member of claim 1, wherein the porous fibrous carrier layer comprises bicomponent filaments, preferably polyester bicomponent filaments, or staple fibers, preferably bicomponent polyester staple fibers.

16. 2. A trim member according to claim 1, wherein the porous fibrous carrier layer has a thickness of from 1 mm to 10 mm, preferably from 2 mm to 7 mm.

17. The area weight of the porous fibrous carrier layer is 600 g / m ２ ~2500g / m ２ , preferably 800 g / m ２ ~1700g / m ２ , more preferably 900 g / m ２ ~1400g / m ２ The trim member of claim 1 , wherein:

18. A method for manufacturing a trim member according to any one of claims 1 to 17, comprising at least the following steps: (a) forming the porous fibrous carrier layer, preferably using at least one of cold molding, hot molding, and steam injection molding; (b) forming the embossed foil, preferably using at least one of vacuum forming, injection molding, blow molding, and thermal molding; and (c) locally bonding the embossed foil onto the porous fibrous carrier layer, preferably using one of ultrasonic welding or gluing.

19. Use of the trim member according to any one of claims 1 to 17 as an underbody liner, an under-engine liner, or a wheelhouse outer liner.

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