Component for a vehicle body outer skin

Abstract

The invention relates to a component for a vehicle body outer skin, the component being made of fibre-reinforced plastic or of a fibre-plastic composite. The fibre-plastic composite has a plurality of fibre layers, namely: at least one natural fibre intermediate layer comprising a textile fabric consisting of natural fibres; and a natural fibre outer layer comprising a textile fabric consisting of natural fibres. Furthermore, the fibre-plastic composite has a nonwoven fibre layer or a surface-balancing layer which is arranged between the natural fibre intermediate layer and the natural fibre outer layer.

Description

[0001] Body outer skin component

[0002] The invention relates to an outer body skin component for a motor vehicle body, for example a passenger car or a commercial vehicle.

[0003] The body of a passenger car is typically constructed using a self-supporting shell construction. The body is usually made of steel or aluminum, or a combination of these materials. Sometimes an outer body shell component is also made of a fiber-plastic composite, such as carbon fiber or glass fiber.

[0004] It is also known to produce a fiber-plastic composite with natural fibers. Natural fibers are usually somewhat thicker and less homogeneous than chemical fibers, so a fiber-plastic composite with natural fibers typically also has a less smooth surface. Natural fibers are made from a renewable raw material and have the advantage of generally having a better carbon footprint than chemical fibers.

[0005] It is the object of the present invention to create a body outer skin component made of a fiber-plastic composite that is produced sustainably but still meets quality requirements for a surface finish.

[0006] This object is achieved by a body outer skin component having the combination of the features of claim 1. Advantageous further developments are mentioned in the dependent claims.

[0007] According to the invention, a body outer skin component is made of fiber-reinforced plastic or a fiber-plastic composite. The fiber-plastic composite has several fiber layers, namely at least one natural fiber intermediate layer comprising a textile fabric consisting of natural fibers and a natural fiber outer layer comprising a textile fabric consisting of natural fibers. Furthermore, the fiber-plastic composite has a nonwoven fiber layer or a surface compensation layer arranged between the natural fiber intermediate layer and the natural fiber outer layer.

[0008] The natural fibers of the natural fiber intermediate layer and the natural fiber outer layer have a relatively large thickness and are somewhat more inhomogeneous compared to most chemical fibers, which results in a less smooth surface.

[0009] The intermediate arrangement of the nonwoven fiber layer or surface leveling layer enables a smoother surface or compensates for unevenness resulting from the natural fiber layers.

[0010] The natural fiber interlayer preferably has a basis weight of 200 gsm - gsm = g / m 2 - up to 600 gsm, preferably 300 gsm.

[0011] The natural fiber outer layer preferably has a basis weight of 240 gsm.

[0012] The outer body skin component can also be a body attachment. The outer body skin component can be screwed, riveted, clipped, and / or glued to the vehicle body.

[0013] Preferably, the nonwoven fiber layer is directly adjacent to the natural fiber outer layer.

[0014] Furthermore, the natural fiber intermediate layer is advantageously directly adjacent to the nonwoven fiber layer.

[0015] This allows the nonwoven fiber layer to better compensate for any unevenness in the natural fiber layers.

[0016] According to a preferred embodiment, a protective fiber layer adjoins the outside of the natural fiber outer layer.

[0017] The protective fiber layer can protect the natural fiber outer layer during the manufacturing process, for example, an RTM process. In particular, during the RTM process, any mold release agent remaining on the outer layer is removed by mechanical processing, such as grinding. Mechanical processing can damage the natural fiber outer layer. Thanks to the protective fiber layer, the natural fiber outer layer remains unaffected by mechanical processing. The protective fiber layer is preferably the outermost fiber layer.

[0018] Advantageously, the protective fiber layer consists of transparent chemical fibers, for example glass fibers or polymer fibers.

[0019] This makes the natural fiber outer layer visible through the protective fiber layer. Should the fibers of the protective fiber layer be abraded or similarly damaged during the aforementioned mechanical processing to remove the release agent, this will not be visible due to the transparency of the fibers.

[0020] Preferably, the protective fiber layer is formed from a fabric.

[0021] The protective fiber layer can have a low basis weight of, for example, 40 gsm to 100 gsm, preferably 50 gsm to 70 gsm, particularly preferably 50 gsm.

[0022] According to a preferred embodiment, the nonwoven fiber layer consists of chemical fibers, in particular of very fine fibers.

[0023] Most synthetic fibers can be produced in thinner thicknesses than natural fibers. This allows the nonwoven fiber layer to better compensate for the more inhomogeneous natural fiber layers.

[0024] The preferred chemical fibers of the nonwoven fiber layer are PES fibers.

[0025] The nonwoven fiber layer preferably has a basis weight of 50 gsm to 200 gsm, for example 60 gsm to 100 gsm, particularly preferably 60 gsm.

[0026] Furthermore, several natural fiber intermediate layers can be arranged adjacent to one another.

[0027] The body outer skin component can be manufactured using the so-called RTM process, i.e., the resin injection molding (RESIN TRANSFER MOLDING) process. According to a preferred embodiment, the body outer skin component further comprises a fiber center layer comprising a textile fabric made of chemical fiber.

[0028] The fiber middle layer serves in particular as a flow aid for a resin of the plastic matrix during a manufacturing process of the fiber-plastic composite or the body outer skin component.

[0029] The middle fiber layer is formed in particular by a knitted fabric.

[0030] The resin can flow particularly well through a knitted fabric.

[0031] A knitted fabric can be particularly well realized with a synthetic fiber, especially a thin synthetic fiber, so synthetic fibers, such as PES, are preferable to natural fibers for the knitted fabric. A thinner fiber, in turn, allows for a thinner fiber core, which is advantageous in terms of weight and component thickness. For a knitted fabric made of natural fibers, thicker fibers would have to be used.

[0032] The fiber middle layer preferably has a basis weight of 100 gsm to 400 gsm, particularly preferably 130 gsm.

[0033] According to a preferred embodiment, the natural fiber intermediate layer is formed from a non-woven fabric or a woven fabric. A non-woven fabric is advantageous in that it can be produced in any fiber orientation. This allows for reduced waste compared to a woven fabric.

[0034] The natural fiber interlayer can have a fiber orientation of +457 -45°.

[0035] A fiber orientation offset by 90° enables a nearly isotropic behavior of the fiber interlayer or body shell component. If anisotropic material or component behavior is desired, other fiber orientations are also possible.

[0036] The natural fiber outer layer can have a fiber orientation of 0-790°. However, a unidirectional orientation of the fibers in the fiber outer layer is also possible.

[0037] The natural fibers can be plant fibers, for example, bast fibers, especially flax, hemp, or bamboo, or seed fibers or leaf fibers. Flax fibers are particularly preferred, as they are readily available. Flax fibers also have a particularly homogeneous structure.

[0038] Furthermore, flax fibers are cost-effective.

[0039] The chemical fibers can be organic or inorganic. Organic chemical fibers include synthetic polymers, for example. Polyester (PES) is particularly preferred. Polyester absorbs very little moisture. Polyester chemical fibers are comparatively inexpensive if of good quality.

[0040] A layer of paint, in particular a clear coat, is preferably applied to one outer side or to both outer sides of the body outer skin component.

[0041] The natural fiber outer layer is visible through the clear varnish layer.

[0042] The layers of the body outer skin component are preferably constructed symmetrically to the center layer. In particular, the natural fiber intermediate layer and the natural fiber outer layer, and optionally the protective fiber layer (if present), are arranged and formed symmetrically to the center layer.

[0043] A plastic matrix of the fiber-reinforced plastic is advantageously a thermosetting plastic made with a liquid resin, in particular an epoxy resin, and a corresponding hardener.

[0044] The body outer skin component may be a vehicle roof outer skin or a fender outer skin or a front cover outer skin or a side panel outer skin or a rocker panel or a bumper panel.

[0045] Chemical fibers according to the present invention are synthetically produced organic or inorganic fibers and can therefore be, among other things, so-called plastic fibers. In particular, chemical fibers are non-metallic fibers. Natural fibers, in turn, are non-synthetically produced fibers that occur naturally, for example, in plants, and are obtained, for example, from plants without synthesis. Natural fibers are not plastic fibers. In particular, plastic fibers that are synthesized or produced from hydrocarbons obtained from plants are not natural fibers within the meaning of the present invention.

[0046] The features mentioned above can be combined with each other as far as possible and reasonable.

[0047] A brief description of the figure follows.

[0048] Fig. 1 is a schematic sectional view of a body outer skin component according to an embodiment of the present invention.

[0049] An embodiment of the present invention is explained below with reference to Figure 1.

[0050] Figure 1 shows a schematic section through a body outer skin component 1, in particular a vehicle roof outer skin, made of fiber-reinforced plastic or a fiber-plastic composite according to the exemplary embodiment of the present invention. The fiber-plastic composite is produced using an RTM process. The section shows the individual layers of the fiber-plastic composite. The layers of the fiber-plastic composite differ in terms of the fiber layers. The fiber-plastic composite has several fiber layers, all embedded in the same plastic matrix. The fiber-plastic composite has an outer natural fiber outer layer 3 and an inner natural fiber outer layer 3. The outer natural fiber outer layer 3 is thus on an outer side of the body outer skin component 1. The inner natural fiber outer layer 3 is thus on an inner side of the body outer skin component 1.The two natural fiber outer layers 3 are formed by a fabric made of flax fibers.

[0051] Adjacent to the outer natural fiber layer 3 is a nonwoven fiber layer 11. The nonwoven fiber layer 11 can also be referred to as a surface balancing layer. The nonwoven fiber layer 11 has the lowest possible basis weight, for example, approximately 60 g / m² (=gsm) and is made of PES fibers.

[0052] Furthermore, an outer natural fiber intermediate layer 5 is arranged adjacent to the nonwoven fiber layer 11. In other words, the nonwoven fiber layer 11 is arranged between the outer natural fiber outer layer 3 and the outer natural fiber intermediate layer 5. The natural fiber intermediate layer 5 is formed by a flax fiber interfacing.

[0053] A fiber core layer 7 is arranged in the center of the fiber-reinforced plastic composite. The fiber core layer 7 consists of a knitted fabric made of PES fibers and serves as a flow aid in the RTM manufacturing process. The fiber core layer 7 allows the liquid resin to be better distributed throughout the component during the manufacturing process.

[0054] The fiber middle layer 7 is arranged between the outer natural fiber intermediate layer 5 and an inner natural fiber intermediate layer 5. Like the outer natural fiber intermediate layer 5, the inner natural fiber intermediate layer 5 is formed by a flax fiber interlace.

[0055] The nonwoven fiber layer 11 between the outer natural fiber intermediate layer 5 and the outer natural fiber outer layer 3 serves to level the surface, since most natural fibers, especially the flax used in the exemplary embodiment, are less homogeneous than chemical fibers and usually have a larger fiber diameter than chemical fibers. Due to this inhomogeneity and the relatively large fiber diameter, a surface of the body outer skin component 1 becomes relatively uneven or less smooth. The intermediate nonwoven fiber layer 11 reduces these unevennesses.

[0056] There is no additional fiber layer between the outer fiber layers 3 and the intermediate fiber layers 5, and between the intermediate fiber layers 5 and the middle fiber layer 7. However, the outer fiber layers 3 can consist of several superimposed woven layers of PES fibers. Likewise, the intermediate fiber layers 5 can comprise several superimposed flax fiber interlacing layers.

[0057] The natural fiber intermediate layers 5 have a fiber orientation of +457° to -45°. The natural fiber outer layers 3 have a fiber orientation of 0790°.

[0058] The flax fibres of the intermediate fibre layers 5 and the natural fibre outer layers could be replaced by other suitable natural fibres.

[0059] A paint layer 9, in particular a clear coat, is also applied to the outside of the body outer skin component 1. In the case of a clear coat, the fabric structure of the fiber outer layer 3 is visible on the body outer skin component 1.

[0060] If the body outer skin component 1 is manufactured using an RTM process, residues of a release agent remain on the body outer skin component 1, which must be removed before the paint or paint layer 9 is applied, since otherwise the paint layer 9 will adhere poorly to the body outer skin component 1. These release agent residues are removed by sanding. During sanding, it may happen that the fibers of the uppermost fiber layer, i.e., for example, the outer natural fiber layer, are partially abraded. In the case in which the paint layer 9 is transparent, i.e., a clear coat, the abraded fibers are visible and create a different appearance of the surface of the body outer skin component 1 than with unsanded fibers.

[0061] To prevent this visual change to the surface, a protective fiber layer 13 can optionally be arranged on the outside of the outer natural fiber outer layer 3. If the protective fiber layer 13 is provided, the protective fiber layer 13 and not the natural fiber outer layer 3 is the outermost fiber layer. The protective fiber layer 13 has transparent fibers, for example glass fibers, in the form of a woven fabric. If these transparent fibers are abraded during the aforementioned grinding process to remove the release agent, this is not visible. Because of the protective fiber layer 13, the natural fiber outer layer is not impaired or abraded during the grinding process. Thus, the natural fiber outer layer 3 is visible through the essentially transparent protective fiber layer 13 and determines the appearance of the body outer skin component 1.The protective fiber layer 13 has a low basis weight of approximately 50 gsm, so that the protective fiber layer 13 has relatively little influence on the mechanical properties of the body outer skin component 1. Nevertheless, it is preferred that an inner protective fiber layer 13 is also arranged on an inner side of the body outer skin component 1 in order to have the most symmetrical structure of the layers and to minimize the influence on the mechanical properties and component distortion.

[0062] The layers of the body outer skin component 1 are essentially constructed symmetrically to the center of the body outer skin component 1, with the exception of the nonwoven fiber layer 11, so that the component does not warp during manufacturing and has the same mechanical properties in both bending directions. The nonwoven fiber layer 11 has a low basis weight, so that the influence of the nonwoven fiber layer 11 on warping of the component and also on the mechanical properties of the finished body outer skin component 1 can be neglected. Furthermore, the paint layer 9 can also be applied to the inside of the body outer skin component. If a smoother surface is desired on the inside of the body outer skin component 1, the nonwoven fiber layer 11 can also be arranged between the inner natural fiber outer layer 3 and the inner natural fiber intermediate layer 5.

[0063] The plastic matrix of the fiber-reinforced plastic is made of epoxy resin and a corresponding hardener.

Claims

Patent claims 1. Body outer skin component (1) made of fiber-reinforced plastic or of a fiber-plastic composite, which has a plurality of fiber layers with at least one natural fiber intermediate layer (5) comprising a textile fabric consisting of natural fibers and a natural fiber outer layer (3) comprising a textile fabric consisting of natural fibers, furthermore with a nonwoven fiber layer (11) which is arranged between the natural fiber intermediate layer (5) and the natural fiber outer layer (3).

2. Body outer skin component according to claim 1, wherein the nonwoven fiber layer (11) is in particular directly adjacent to the natural fiber outer layer (3).

3. Body outer skin component according to claim 1 or 2, wherein the natural fiber intermediate layer (5) is in particular directly adjacent to the nonwoven fiber layer (11).

4. Body outer skin component according to one of claims 1 to 3, wherein a protective fiber layer (13) adjoins the outside of the natural fiber outer layer (3), wherein the protective fiber layer (13) is in particular the outermost fiber layer, and wherein the protective fiber layer (13) is formed, for example, from transparent chemical fibers, for example from glass fibers or polymer fibers, and wherein the protective fiber layer (13) is preferably formed from a woven fabric, and wherein the protective fiber layer (13) advantageously has a low basis weight of, for example, 40 gsm to 100 gsm, preferably 50 gsm to 70 gsm, particularly preferably 50 gsm.

5. Body outer skin component according to one of claims 1 to 4, wherein the nonwoven fiber layer (11) consists of chemical fibers, in particular of very fine fibers, for example PES fibers, and wherein the nonwoven fiber layer (11) in particular has a basis weight of 50 gsm to 200 gsm, for example 60 gsm to 100 gsm, particularly preferably 60 gsm.

6. Body outer skin component according to one of claims 1 to 5, further comprising a fiber middle layer (7) comprising a textile fabric made of chemical fiber, for example PES fibers, wherein the fiber middle layer (7) is formed in particular by a knitted fabric, and wherein the fiber middle layer (7) for example, has a basis weight of 100 gsm to 400 gsm, in particular approximately 130 gsm.

7. Body outer skin component according to one of claims 1 to 6, wherein the natural fiber intermediate layer (5) is formed from a scrim or woven fabric, and wherein the fiber orientation is in particular +45 -45°, and wherein the natural fiber intermediate layer has, for example, a basis weight of 200 gsm to 600 gsm, in particular approximately 300 gsm.

8. Body outer skin component according to one of claims 1 to 7, wherein the natural fiber outer layer (5) is formed from a woven or non-woven fabric, and wherein the fiber orientation is in particular 0 90°, and wherein the natural fiber outer layer has, for example, a basis weight of 150 gsm to 400 gsm, preferably 240 gsm.

9. Body outer skin component according to one of claims 1 to 8, wherein the natural fibers are plant fibers, for example bast fibers, in particular flax fibers, or seed fibers or leaf fibers.

10. Body outer skin component according to one of claims 1 to 9, wherein the body outer skin component (1) further comprises a lacquer layer (9), in particular a clear lacquer layer, on its outer side.

11. Body outer skin component according to one of claims 1 to 10, wherein a plastic matrix of the fiber-reinforced plastic consists of a thermosetting plastic, in particular based on epoxy resin.

12. Body outer skin component according to one of claims 1 to 11, wherein the body outer skin component (1) is a vehicle roof outer skin or a fender outer skin or a front cover outer skin or a side wall outer skin or a sill panel or a bumper panel.

Images