Fiber fleece panel for the exterior of a vehicle and method for manufacturing the same

Abstract

Fiber fleece panel for the exterior of a vehicle, comprising: Ground fibers with a non-circular cross-section and Adhesive fibers with a non-circular cross-section, wherein the base fibers are present in an amount of 50 wt.% or more, based on the total weight of the fiber web, and Both the base fibers and the adhesive fibers have a linear density of approximately 6 to 15 denier and a shape measure (α) with respect to their non-circular shape of approximately 1.3 to 3.0, where the shape dimension (α) with respect to the non-circular shape is given by the following equation 1 Form dimension ß ( α ) with respect to the non-circular shape = P 4 π A , is reproduced where P is the length of the cross-sectional circumference of the fibers and A indicates the cross-sectional area of ​​the fibers, wherein the cross-sectional shape of the ground fibers and the cross-sectional shape of the adhesive fibers are selected from the group consisting of an eight-leaflet shape, a W-shaped shape, a shape with cutouts, a flattened shape, a cross-shaped shape, a triangular shape and a star-shaped shape, the adhesive fibers are composed of a sheath and a core, and wherein the length P of the cross-sectional circumference of the base fibers or the adhesive fibers is in a range of approximately 140 to 180 µm and the cross-sectional area A of the base fibers or the adhesive fibers is in a range of 280 to 1,500 µm 2 lies.

Description

Technical field

[0001] The present invention relates to a fiber fleece panel or fiber fleece panel for the exterior of a vehicle and to a method for manufacturing the same. The fiber fleece panel can have significantly improved stiffness and better noise absorption. background

[0002] While driving, external noises penetrate the vehicle's interior in various ways. In particular, noises caused by friction between the tires and the road surface, noises from combustion gases escaping the exhaust system at high temperatures and pressure, mechanical noises generated while the engine is running, and similar sounds enter the vehicle's interior, are heard by the occupants, and disturb the comfort and quiet of the vehicle.

[0003] To ensure comfort and quiet in a vehicle, components such as protective covers and wheel arches were installed to dampen road noise in the lower part of the vehicle while driving and to protect the underbody of the vehicle chassis from dirt particles like mud and stones kicked up by the road. In the prior art, these components were mostly made of a plastic material, such as polypropylene (PP) and glass fiber reinforced PP. However, plastic materials have several problems. For example, they are susceptible to impacts and, because they are not airtight, are unable to absorb noise.

[0004] Recently, heat-moldable, densified felt materials have been used to ensure impact resistance and sound-absorbing properties. However, heat-moldable, densified felts lack sufficient stiffness and can therefore only be used to a limited extent in large-area components, such as protective covers. Furthermore, when a felt is densified to increase the stiffness of the fiber fleece, it becomes less effective at absorbing noise.

[0005] Components made from a dense nonwoven fiber material were thus produced by preheating a felted cloth, made by piercing it with a needle, in an oven at a predetermined temperature for a predetermined time and then forming it into a component in a cold mold, or by pressing the felted cloth – without any extra preheating – in a hot mold at a predetermined temperature for a predetermined time and forming it into a component.

[0006] A conventional nonwoven fabric consists of polyethylene terephthalate (PET) fibers as the base fibers and a two-component PET fiber as bonding fibers or adhesive fibers to connect the PET fibers, but it can also consist solely of PET fibers. In the prior art, the mechanical properties of a dense nonwoven fabric have been improved by increasing the areal density (weight per unit area) at a given thickness, or conversely, by further reducing the thickness at a given areal density to increase the bonding strength between the fibers.

[0007] However, an increase in surface density is accompanied by an increase in the weight of the components and higher material costs, and a reduction in thickness means that the densified fiber fleece is less able to absorb noise.

[0008] Since the fibers in the prior art typically have a round or circular cross-section, the contact area between the fibers is so small that the bonding strength between them can only be improved to a limited extent, and the bulkiness of the felted fabric is too low during the heating process for shaping purposes, if the treatment is to take place at a predetermined temperature. Only the surface of the fabric is melted, while the intermediate layers remain as fibers, thus reducing the strength.

[0009] There is therefore a need to investigate nonwoven fiber panels that can be used in the exterior of a vehicle, that can absorb noise better and that are or remain stiff enough.

[0010] The information disclosed in the Background section above is intended only to clarify the background of the invention and may therefore contain information that does not constitute prior art as already known to a person skilled in the art in this country. Summary of the invention

[0011] In preferred aspects, the present invention provides a fiber fleece panel, i.e., a panel made of a fiber fleece, for the exterior of a vehicle which is stiffer and better able to absorb noise.

[0012] In one aspect, the present invention provides a non-woven fiber sheet for the exterior of a vehicle. The non-woven fiber sheet can contain: base fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section. The base fibers can be present in an amount of about 50% by weight or more, based on the total weight of the non-woven fiber sheet. The base fibers and the adhesive fibers can have a linear density of about 6 to 15 denier and a dimension of non-circular shape of about 1.3 to 3.0.

[0013] The terms “base fibers” or “matrix fibers,” as used herein, include fibers that form the fiber web or fabric as a major component. For example, the base fibers constitute a proportion of more than approximately 25 wt.%, 30 wt.%, 40 wt.%, 50 wt.%, 60 wt.%, 70 wt.%, 80 wt.%, or 90 wt.%. Preferred base fibers may constitute an amount of approximately 50 wt.% or more in the fiber web of the present invention.

[0014] The term "adhesive fibers," as used herein, includes fibers that bond base fibers or other fibers together. Preferred adhesive fibers may include two-component fibers. Preferred two-component fibers, as used herein, may contain two different polymers and be formed from the two polymers using only one spinneret, such that both polymers can be contained in the same filament. Furthermore, preferred adhesive fibers may have a sheath and core structure formed during production from the two-component fibers such that one polymer component (core) is at least partially surrounded by the other polymer component (sheath).

[0015] The shape dimension (α) with respect to the non-circular shape can be determined using the following equation 1: Form dimension(α) with respect to the non-circular shape = P4πA, where P is the length of the cross-sectional circumference of the fibers and A specifies the cross-sectional area of ​​the fibers.

[0016] The cross-sectional shape of the base fibers and the cross-sectional shape of the adhesive fibers can preferably be selected from the group consisting of an eight-leaflet shape, a W-shaped shape, a shape with recesses, a flattened shape, a cross-shaped shape, a triangular shape, and a star-shaped shape.

[0017] The base fibers can be selected accordingly from the group consisting of polyethylene terephthalate, polypropylene, nylon, acrylic, viscose fibers and aramid fibers.

[0018] The adhesive fibers can contain one or more fibers selected from the group consisting of low-melting-point polyethylene terephthalate fibers, polypropylene fibers, and polyethylene. Preferably, the adhesive fibers have a structure consisting of a sheath and a core.

[0019] In a preferred application, the adhesive fiber material can have a lower melting point than the material of the conventional base fibers, allowing the adhesive fibers to melt and act as an adhesive or bonding agent between the base fibers during hot forming or heat-bonding, while the base fiber material retains its original form. Thus, the adhesive fibers or the adhesive fiber material can have a melting point approximately 30 °C, 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 150 °C, or 200 °C lower than the melting point of the base fibers or the base fiber material.

[0020] The length P of the cross-sectional circumference of the base fibers or the adhesive fibers can be in a range of approximately 140 to 180 µm and the cross-sectional area A of the base fibers or the adhesive fibers can be in a range of approximately 280 to 1,500 µm. 2 lay.

[0021] In addition, a material for a protective cover for the exterior of a vehicle is provided, which may contain a fiber fleece panel as described herein.

[0022] In a further aspect, the present invention provides a method for manufacturing a non-woven fiber sheet for the exterior of a vehicle. The method can include forming a fiber composite containing base fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section into the non-woven fiber sheet. The base fibers can be present in an amount of about 50 wt.% or more, based on the total weight of the non-woven fiber sheet, and the base fibers or the adhesive fibers can have a linear density of 6 to 15 denier. The base fibers or the adhesive fibers can also have a shape dimension (α) with respect to the non-circular shape, as defined in Equation 1, of 1.3 to 3.0.

[0023] The fiber fleece sheet can preferably be shaped by punching holes with a needle or by heat binding.

[0024] The cross-sectional shape of the base fibers and the cross-sectional shape of the adhesive fibers may preferably be selected from the group consisting of an eight-leaved shape, a W-shaped shape, a shape with recesses, a flattened shape, a cross-shaped shape, a triangular shape and a star-shaped shape.

[0025] The base fibers can be selected accordingly from the group consisting of polyethylene terephthalate, polypropylene, nylon, acrylic, viscose fibers and aramid fibers.

[0026] The adhesive fibers can contain one or more fiber types selected from the group consisting of low-melting polyethylene terephthalate fibers, polypropylene fibers and polyethylene, and can be composed of a sheath and a core.

[0027] According to equation 1, the length (P) of the cross-sectional circumference of the base fibers or the adhesive fibers can be in a range of approximately 140 to 180 µm and the cross-sectional area (A) of the base fibers or the adhesive fibers can be in a range of approximately 280 to 1,500 µm. 2 lay.

[0028] Furthermore, a vehicle containing the fiber fleece panel as described herein will be provided. The fiber fleece panel can preferably be installed on the exterior of the vehicle.

[0029] The fiber fleece panel for the exterior of a vehicle according to the present invention, when a yarn with a non-circular cross-section is used, can have a large specific surface area, thus improving the adhesion between the fibers, and it can exhibit significantly better mechanical properties. Furthermore, its heat formability can be improved, since the heat can be transferred efficiently during heating due to the high bulk and large specific area of ​​the fibers.

[0030] Due to the decrease in the area density of the fiber fleece because of its better stiffness, the fiber fleece panel can be lighter and it can absorb noise much better.

[0031] Further aspects and preferred embodiments of the invention are explained below. Brief description of the characters

[0032] The features of the present invention, as well as those specified above, are described in detail below with reference to certain exemplary embodiments shown in the accompanying figures, which are shown for illustrative purposes only and are not intended to limit the present invention in any way. The following applies to the figures: The Fig. Figure 1 shows the exemplary eight-leaved, W-shaped, recessed, flattened and star-shaped cross-sectional forms of exemplary base fibers and adhesive fibers according to an exemplary embodiment of the present invention.

[0033] It should be understood that the accompanying figures are not necessarily to scale, but rather a somewhat simplified representation of various exemplary features that illustrate the principles underlying the invention. The specific features for carrying out the present invention as disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes, will be determined in part by the conditions and circumstances of the specific intended application and use.

[0034] In the figures, the reference numerals denote the same or equivalent parts of the present invention. Detailed description

[0035] The terminology used herein serves solely to describe certain exemplary embodiments and is therefore not intended to limit the invention in any way. As used herein, the singular forms "a" and "the" are to include the plural forms unless the context clearly indicates otherwise. Furthermore, it should be understood that the terms "includes" and / or "comprehensive," when used in this description, indicate the presence of the aforementioned features, numbers, steps, operations, elements, and / or components / parts, but do not exclude the presence or addition of one or more further features, numbers, steps, operations, elements, components / parts, and / or groups thereof.As used herein, the term “and / or” includes any and all combinations of one or more of the related items listed.

[0036] Unless explicitly stated or evident from the context, the term "approximately," as used herein, should be understood as lying within a range of normal scientific tolerances, for example, within 2 standard deviations from the mean. "Approximately" may be understood as lying within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clearly indicated by the context, all numerical values ​​stated herein are to be understood as including the term "approximately."

[0037] It should be understood that the term "vehicle" or "vehicle-" or any other similar term as used herein includes motor vehicles in general, such as passenger cars, including sports utility vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft, including a variety of boats and ships, aircraft and the like, as well as hybrid vehicles, electric vehicles, convertible hybrid-electric vehicles, hydrogen-powered vehicles and other vehicles powered by alternative fuels (e.g., fuels derived from a source other than petroleum). As defined herein, a hybrid vehicle is a vehicle that has two or more sources of propulsion, for example, a vehicle that runs on both gasoline and electricity.

[0038] The following section will describe in detail various embodiments of the present invention, which are illustrated by way of example in the accompanying figures and described below. Although the invention is described with reference to exemplary embodiments, it should be understood that the present description is not intended to limit the invention to these exemplary embodiments. Rather, the invention is intended to cover not only the exemplary embodiments but also various alternatives, modifications, equivalents, and further embodiments that may be included in the proper sense and scope of the present invention as defined in the accompanying claims.

[0039] Since the present invention can be modified in various ways and may comprise several exemplary embodiments, only certain exemplary embodiments are shown in the figures and are described in more detail in the comprehensive description. However, the description is not intended to limit the present invention to the specific exemplary embodiments shown, and it should be understood that all modifications, equivalents, and omissions inherent in the actual meaning and technical scope of the present invention are included. Where it can be assumed that a comprehensive description of the generally known prior art in the description of the present invention would obscure its meaning, such a comprehensive description is omitted.

[0040] The present invention provides a nonwoven fiber sheet for the exterior of a vehicle. The nonwoven fiber sheet can contain base fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section. The base fibers can be present in an amount of 50% by weight or more, based on the total weight of the nonwoven fiber sheet. The base fibers with a non-circular cross-section or the adhesive fibers with a non-circular cross-section can have a linear density of about 6 to 15 denier and a shape factor (α) with respect to their non-circular shape of about 1.3 to 3.0. The shape factor (α) with respect to the non-circular shape can be determined using the following equation 1. Form dimension(α) with respect to the non-circular shape = P4πA.

[0041] In equation 1, P is the length of the cross-sectional circumference of the fibers and A gives the cross-sectional area of ​​the fibers.

[0042] Fiber fleece panels for the exterior of a vehicle are described in more detail below using specific exemplary embodiments of the present invention.

[0043] In the prior art, the problem is that the contact area between the fibers is not sufficiently large due to the circular cross-section of the fibers to improve the bonding strength. Furthermore, the bulkiness of the felt during heating for shaping purposes is so low with a circular cross-section that, during treatment at a given temperature, only the fabric surface is melted, while the intermediate layers remain as fibers, thus reducing the strength.

[0044] The present inventors have therefore confirmed in experiments that when fibers with a non-circular cross-section and a linear density in a given area and a shape dimension with respect to the non-circular shape in a given area are used as base fibers and adhesive fibers for a fiber fleece, the heat can be transferred well during heating due to the high bulkiness and the large specific surface area of ​​the fibers, and thereby the thermoformability and mechanical properties can be improved, the weight can be reduced by reducing the areal density of the fiber fleece due to the improved stiffness, and noise can be absorbed better.

[0045] In one aspect of the present invention, a nonwoven fiber sheet is provided for the exterior of a vehicle. The nonwoven fiber sheet can contain base fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section. The base fibers with a non-circular cross-section can be present in an amount of 50% by weight or more, based on the total weight of the nonwoven fiber sheet.

[0046] The base fibers with a non-circular cross-section or the adhesive fibers with a non-circular cross-section can, in particular, have a linear density of about 6 to 15 denier and a shape dimension with respect to their non-circular shape of about 1.3 to 3.0.

[0047] In one preferred aspect, fibers with a non-circular cross-section can have a surface area that is approximately 2 to 5 times larger than the surface area of ​​conventional fibers with a circular cross-section.

[0048] Normally, the friction of a sound wave against a given material reduces its viscosity, which leads to a decrease in the noise level due to the conversion of the sound wave's mechanical energy into heat energy. Because of the physical phenomenon described above, the fibers used in the present invention, which have a non-circular cross-section, can—unlike ordinary fibers with a circular cross-section—be structured to have an irregular or regular cross-section, thereby offering certain advantages. For example, to reduce the viscosity of a sound wave, the surface area of ​​the fibers can be maximized to improve noise absorption.

[0049] Conventional PET fibers have a circular cross-section, meaning the bonding force between the fibers can only act at specific contact points. Fibers with a non-circular cross-section, however, have a larger specific surface area, which increases the adhesion between the fibers and thus improves their mechanical properties. Furthermore, due to their high bulk and large specific area, heat is transferred efficiently during heating, improving both their thermoformability and mechanical properties.

[0050] In the fiber fleece panel according to the invention, for which fibers with a non-circular cross-section are used and whose surface area is dimensioned as large as described above, the acoustic properties (noise, vibration and harshness, NVH = noise, vibration, harshness) which can be as good as or better than those of the sound-absorbing material from the prior art, are evident even when its surface density is smaller than that of the sound-absorbing material from the prior art, which allows the vehicle to be built lighter and an advantage is that the fiber fleece panel according to the present invention can absorb noise much better than a sound-absorbing material made of conventional fibers with a circular cross-section that has the same areal density.

[0051] Most known synthetic fibers have a circular cross-section. However, in preferred aspects of the present invention, the fibers can be formed such that they do not have a circular cross-section. For this purpose, the spinneret can be manufactured, for example, with a desired shape, such as an eight-lobed shape, a W-shaped shape, a shape with recesses, a flattened shape, a cross-shaped shape, a triangular shape, or a star-shaped shape. As a result, the spun thread has a cross-sectional shape other than a circular one, the shape of which can correspond to the shape of the spinneret.Since fibers with a non-circular cross-section have a larger surface area than conventional fibers with a circular cross-section, the surface area of ​​the nonwoven fabric can be maximized, and a sound wave can lose viscosity at its surface, which is one of the most important factors in sound properties, leading to an improvement in sound absorption.

[0052] The specific shape of the non-circular cross-section need not be particularly restricted, but may preferably be an eight-lobed shape, a W-shaped shape, a shape with recesses, a flattened shape, a cross-shaped shape, a triangular shape and a star-shaped shape, and preferably a W-shaped shape and an eight-lobed shape, and may be selected with regard to the required mechanical properties and the desired sound absorption.

[0053] The Fig.Figure 1 shows exemplary cross-sectional shapes of exemplary base fibers with a non-circular cross-section and exemplary adhesive fibers with a non-circular cross-section as an eight-leaved shape, W-shaped shape, shape with recesses, flattened shape and star-shaped shape.

[0054] The base fibers with a non-circular cross-section can be melt-spun, and they can be selected from the group consisting of polyethylene terephthalate, polypropylene, nylon, acrylic, viscose fibers, and aramid fibers. For mass production, and due to its heat resistance, nylon can be used.

[0055] The adhesive fibers can be fibers that create adhesion between or bond the base fibers with a non-circular cross-section. These adhesive fibers can contain low-melting polyethylene terephthalate fibers, polypropylene fibers, and the like. The non-circular adhesive fibers can contain one or more fiber types selected from the group consisting of low-melting polyethylene terephthalate fibers, polypropylene fibers, and polyethylene. In particular, the non-circular adhesive fibers can be composed of a sheath and a core. For example, low-melting polyethylene terephthalate can have a sheath section and a core section that are spun together in a sheath-core structure.The outer layer can have any shape selected from the group consisting of an amorphous and a crystalline form with a melting point of approximately 180 °C or less, and the core can have a crystalline form with a melting point of approximately 250 °C or more. The core can be melted, in particular, during the forming of a component and can therefore serve to maintain the shape of the fiber-reinforced nonwoven sheet by crosslinking the fibers.

[0056] If the amount of the base fibers with a non-circular cross-section in the present invention is less than about 50 wt.%, the mechanical properties may deteriorate, so the base fibers with a non-circular cross-section should be included in an amount of about 50 wt.% or more, based on the total weight of the fiber fleece sheet.

[0057] The fibers with a non-circular cross-section and the adhesive fibers with a non-circular cross-section can also have a linear density of preferably 6 to 15 denier. If the linear density is less than approximately 6 denier, the tensile moduli of the individual fibers may decrease, resulting in a less stiff fiber web. If the linear density is greater than approximately 15 denier, the number of individual fibers in the fiber web with the same areal density may decrease, potentially impairing the mechanical properties of the fiber web.

[0058] Fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section can exhibit a shape factor of approximately 1.3 to 3.0 with respect to their non-circular shape. If the shape factor is less than approximately 1.3, their surface area cannot be increased sufficiently to achieve a sufficiently circular shape, and therefore the mechanical properties cannot be adequately improved. If the shape factor is greater than approximately 3.0, the crimp may decrease, resulting in fewer contact points between the fibers and a corresponding deterioration of the mechanical properties.

[0059] The shape dimension (α) with respect to the non-circular shape can be represented by the following equation 1, where the length (P) of the cross-sectional circumference of the fibers can be from about 140 to 180 µm and the cross-sectional area (A) of the fibers can be from about 280 to 1,500 µm². 2 can amount to. Form dimension(α) with respect to the non-circular shape = P4πA

[0060] If the fibers have an eight-lobed cross-section, the shape dimension (α) with respect to the non-circular shape of these fibers can be in a range of approximately 1.3 to 3.0, the length (P) of the cross-sectional circumference can be in a range of approximately 140 to 180 µm, and the cross-sectional area (A) can be in a range of approximately 280 to 1,500 µm². 2If the length (P) of the cross-sectional circumference of the fibers is less than approximately 140 µm, the specific surface area of ​​the fibers may decrease, the sound-absorbing properties may not be sufficiently improved, and they may shrink considerably during heat forming due to the reduced fiber thickness. If the length (P) of the cross-sectional circumference of the fibers is greater than approximately 180 µm, the linear density of the fibers may increase, which can reduce the number of individual fibers in a fiber web that possess a specific surface area. Furthermore, noise absorption may be insufficient, excessive gaps may occur between the fibers, and consequently, the stiffness may decrease after heat forming. Therefore, fibers with an eight-sheet cross-section should preferably have a length (P) of the cross-sectional circumference within the range specified above.

[0061] If the cross-sectional area (A) of the fibers is smaller than approximately 280 µm 2 If the cross-sectional area (A) of the fibers is greater than approximately 1,500 µm, a spinneret with an eight-lobed cross-section cannot be produced for the corresponding manufacturing processes, and the actual fibers cannot sufficiently exhibit an eight-lobed cross-section after spinning with the spinneret. 2 If the fibers have a higher denier count and a lower spinning speed, efficiency may decrease. Furthermore, significantly more gaps may occur between the fibers in the felt, causing it to shrink considerably and lose stiffness during heat forming. Therefore, fibers with an eight-sheet cross-section should preferably have a fiber cross-sectional area A within the range specified above.

[0062] In a further aspect of the present invention, a method for producing the fiber fleece sheet for the exterior of a vehicle is provided. The method can comprise forming a fiber composite, comprising base fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section, into a fiber fleece. The base fibers can be present in an amount of about 50 wt.% or more, based on the total weight of the fiber fleece, and the base fibers or the adhesive fibers can have a linear density of 6 to 15 denier and a shape dimension (α) with respect to their non-circular shape of 1.3 to 3.0.

[0063] Preferably, the fiber fleece can be formed by punching holes with a needle or by heat bonding.

[0064] The method for producing the fiber nonwoven sheet according to the present invention can be the same as, or differ from, a conventional method for forming a sheet-shaped component from a nonwoven fabric. The fiber nonwoven sheet can be formed into a component by preheating a needle-punched fabric in an oven when using a cold mold, or by directly forming the fabric when using a hot mold.

[0065] Preferred examples of the present invention are described in detail below with reference to the accompanying figures. However, these examples are intended only to illustrate the present invention and do not in any way limit its scope to the examples given. Examples

[0066] The following examples illustrate the invention and do not limit it in any way. Example 1

[0067] PET fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section, containing low-melting-point PET fibers, were used in a weight ratio of 6:4. A conventional process for producing a heat-bonded fiber web was employed to manufacture the fiber web sheet. The fiber web sheet had a thickness of 2 mm and a basis density of 1,200 g / m². 2 trained.

[0068] The base fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section, as described above, were W-shaped cross-section fibers produced by melt spinning using a W-shaped spinneret, and fibers with a crimp number of 9.8 per inch (2.54 cm), a non-circular shape measure of 2.6, and a linear density of 7 denier were used. Example 2

[0069] PET fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section, containing low-melting-point PET fibers, were used in a weight ratio of 6:4. A conventional process for producing a heat-bonded fiber web was employed to manufacture the fiber web sheet. The fiber web sheet had a thickness of 2 mm and a basis density of 1,200 g / m². 2 trained.

[0070] As base fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section, as described above, fibers with a W-shaped cross-section produced by melt spinning using a W-shaped spinneret were used, and fibers with a crimp number of 9.8 per inch and a shape dimension with respect to the non-circular shape of 2.6 were used, and as base fibers with a non-circular cross-section, fibers with a linear density of 14 denier were used, and as adhesive fibers with a non-circular cross-section, fibers with a linear density of 7 denier were used. Example 3

[0071] PET fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section, containing low-melting-point PET fibers, were used in a weight ratio of 6:4. A conventional process for producing a heat-bonded fiber web was employed to manufacture the fiber web sheet. The fiber web sheet had a thickness of 2 mm and a basis density of 1,200 g / m². 2 trained.

[0072] As base fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section, as described above, fibers with a W-shaped cross-section produced by melt spinning using a W-shaped spinneret were used, and fibers with a crimp number of 9.8 per inch and a shape dimension with respect to the non-circular shape of 2.0 were used, and as base fibers with a non-circular cross-section, fibers with a linear density of 14 denier were used, and as adhesive fibers with a non-circular cross-section, fibers with a linear density of 7 denier were used. Example 4

[0073] PET fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section, containing low-melting-point PET fibers, were used in a weight ratio of 6:4. A conventional process for producing a heat-bonded fiber web was employed to manufacture the fiber web sheet. The fiber web sheet had a thickness of 2 mm and a basis density of 1,200 g / m². 2 trained.

[0074] As base fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section, as described above, fibers with a W-shaped cross-section produced by melt spinning using a W-shaped spinneret were used, and fibers with a crimp number of 9.8 per inch and a shape dimension with respect to the non-circular shape of 2.0 were used, and as base fibers with a non-circular cross-section, fibers with a linear density of 14 denier were used, and as adhesive fibers with a non-circular cross-section, fibers with a linear density of 14 denier were used. Comparative example 1

[0075] For the production of a fiber fleece board with a thickness of 2 mm and an area density of 1,200 g / m² 2Circular PET fibers were used, employing a conventional method for producing a heat-bonded nonwoven fabric. Comparative example 2

[0076] Circular PET fibers and adhesive fibers with a circular cross-section, containing low-melting-point PET fibers, were used in a weight ratio of 6:4. A conventional process for producing a heat-bonded fiber web was employed to manufacture the fiber web sheet. The fiber web sheet had a thickness of 2 mm and a basis density of 1,200 g / m². 2 The fibers had a crimp number of 9.8 per inch each, and fibers with a linear density of 7 denier were used as circular PET fibers, and fibers with a linear density of 4 denier were used as adhesive fibers with a circular cross-section. Comparative example 3

[0077] For the production of a fiber fleece board with a thickness of 2 mm and an area density of 1,200 g / m² 2 W-shaped PET fibers were used, employing a conventional method for producing a heat-bonded nonwoven fabric.

[0078] W-shaped PET fibers, as described above, were fibers with a crimp count of 6.8 per inch, a non-circular shape measure of 3.5, and a linear density of 7 denier. Comparative example 4

[0079] For the production of a fiber fleece board with a thickness of 2 mm and an area density of 1,200 g / m² 2 W-shaped PET fibers were used, employing a conventional method for producing a heat-bonded nonwoven fabric.

[0080] W-shaped PET fibers, as described above, were fibers with a crimp number of 10.3 per inch, a non-circular shape measure of 1.2, and a linear density of 7 denier. Comparative example 5

[0081] For the production of a fiber fleece board with a thickness of 2 mm and an area density of 1,200 g / m² 2 W-shaped PET fibers were used, employing a conventional method for producing a heat-bonded nonwoven fabric.

[0082] W-shaped PET fibers, as described above, were fibers with a crimp number of 9.8 per inch, a non-circular shape measure of 2.6, and a linear density of 4 denier. Comparative example 6

[0083] For the production of a fiber fleece board with a thickness of 2 mm and an area density of 1,200 g / m² 2 W-shaped PET fibers were used, employing a conventional method for producing a heat-bonded nonwoven fabric.

[0084] W-shaped PET fibers, as described above, were fibers with a crimp number of 9.8 per inch, a non-circular shape measure of 2.6, and a linear density of 15 denier. Comparative example 7

[0085] W-shaped PET fibers and circular cross-sectional adhesive fibers containing low-melting-point PET fibers were used in a weight ratio of 6:4. A conventional process for producing a heat-bonded fiber web was employed to manufacture the fiber web sheet. The fiber web sheet had a thickness of 2 mm and a basis density of 1,200 g / m². 2 trained.

[0086] W-shaped PET fibers, as described above, were fibers with a crimp number of 9.8 per inch, a non-circular shape measure of 2.6, and a linear density of 7 denier. Experimental example

[0087] Table 1 below shows the flexural modulus measured according to method A of ISO 178, the tensile strength measured according to type 2 of ISO 527-4, the degree of sound absorption measured according to ISO 354, and the impact strength measured according to ISO 6603-2.

[0088] In comparison to the comparative examples, examples 1 to 4, according to exemplary embodiments of the present invention, had significantly better mechanical properties, such as flexural modulus, tensile strength and impact strength, and were able to absorb noise very well on average.

[0089] By using a yarn with a non-circular cross-section, the fiber fleece for the exterior of a vehicle according to the present invention possessed a large specific surface area, thus effectively improving the bonding strength between the fibers. Due to its high bulk and large specific fiber area, the mechanical properties were significantly improved. Furthermore, since heat transfer during heating was sufficiently efficient, the thermoformability was enhanced. As the areal density of the fiber fleece was reduced due to the improved stiffness, its weight was also reduced, and its sound-absorbing properties were substantially improved. [Table 1] Bending modulus (MPa) Tensile strength (MPa) Average extent of sound absorption Impact resistance (J) Example 1 1450 51 0,44 7,3 Example 2 1200 55 0,42 6,8 Example 3 1150 51 0,40 6,9 Example 4 1190 55 0,39 7,0 Comparative example 1 935 25 0,32 4,5 Comparative example 2 890 31 0,35 5,6 Comparative example 3 1050 35 0,43 6,3 Comparative example 4 1010 26 0,40 4,8 Comparative example 5 732 29 0,44 5,2 Comparative example 6 998 33 0,33 5,2 Comparative example 7 986 28 0,41 6,1

[0090] Although detailed exemplary embodiments of the present invention have been described, a person skilled in the art will recognize that such a specific description merely represents an example of one embodiment and that the scope of the present invention is not limited thereto. The applicable scope of the present invention is accordingly defined by the appended claims and their equivalents.

[0091] The invention has been described in detail with reference to various exemplary embodiments. However, those skilled in the art will recognize that modifications can be made to these embodiments without deviating from the basic principles and the actual purpose of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

[1] Fiber fleece panel for the exterior of a vehicle, comprising: Ground fibers with a non-circular cross-section and Adhesive fibers with a non-circular cross-section, wherein the base fibers are present in an amount of 50 wt.% or more, based on the total weight of the fiber web, and Both the base fibers and the adhesive fibers have a linear density of approximately 6 to 15 denier and a shape measure (α) with respect to their non-circular shape of approximately 1.3 to 3.0, where the shape dimension (α) with respect to the non-circular shape is given by the following equation 1 Form dimension(α) with respect to the non-circular shape = P4πA, is reproduced where P is the length of the cross-sectional circumference of the fibers and A indicates the cross-sectional area of ​​the fibers, wherein the cross-sectional shape of the ground fibers and the cross-sectional shape of the adhesive fibers are selected from the group consisting of an eight-leaflet shape, a W-shaped shape, a shape with cutouts, a flattened shape, a cross-shaped shape, a triangular shape and a star-shaped shape, the adhesive fibers are composed of a sheath and a core, and wherein the length P of the cross-sectional circumference of the base fibers or the adhesive fibers is in a range of approximately 140 to 180 µm and the cross-sectional area A of the base fibers or the adhesive fibers is in a range of 280 to 1,500 µm 2 lies. [2] Fiber nonwoven board according to claim 1, wherein the base fibers are selected from the group consisting of polyethylene terephthalate, polypropylene, nylon, acrylic, viscose fibers and aramid fibers. [3] Fiber nonwoven board according to claim 1, wherein the adhesive fibers comprise one or more fiber types selected from the group consisting of low-melting polyethylene terephthalate fibers, polypropylene fibers and polyethylene. [4] Material for a protective cover for the exterior of a vehicle, which includes a nonwoven fiber sheet according to claim 1. [5] Method for producing a nonwoven fiber sheet for the exterior of a vehicle, the method comprising: Forms of a fiber composite comprising base fibers with a non-circular cross-section and adhesive fibers with a non-circular cross-section, forming a fiber fleece sheet, wherein the basic fibers are contained in an amount of approximately 50 wt.%, based on the total weight of the fiber fleece board and the base fibers or the adhesive fibers have a linear density of about 6 to 15 denier and a shape measure (α) with respect to their non-circular shape of about 1.3 to 3.0, where the shape dimension (α) with respect to the non-circular shape is given by the following equation 1 Form dimension(α) with respect to the non-circular shape = P4πA is reproduced where P is the length of the cross-sectional circumference of the fibers and A indicates the cross-sectional area of ​​the fibers, wherein the cross-sectional shape of the ground fibers and the cross-sectional shape of the adhesive fibers are selected from the group consisting of an eight-leaflet shape, a W-shaped shape, a shape with cutouts, a flattened shape, a cross-shaped shape, a triangular shape and a star-shaped shape, the adhesive fibers are composed of a sheath and a core, and wherein the length P of the cross-sectional circumference of the base fibers or the adhesive fibers is in a range of approximately 140 to 180 µm and the cross-sectional area A of the base fibers or the adhesive fibers is in a range of 280 to 1,500 µm 2 lies. [6] Method according to claim 5, wherein the fiber fleece sheet is produced by boiling with a needle or heat bonding. [7] Method according to claim 5, wherein the base fibers are selected from the group consisting of polyethylene terephthalate, polypropylene, nylon, acrylic, viscose fibers and aramid fibers. [8] Method according to claim 5, wherein the adhesive fibers comprise one or more fiber types selected from the group consisting of low-melting polyethylene terephthalate fibers, polypropylene fibers and polyethylene. [9] Vehicle comprising a nonwoven fiber sheet according to claim 1. [10] Vehicle according to claim 9, wherein the nonwoven fiber sheet is a material for a protective cover of the vehicle.

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