Impact protection plate for battery electric vehicle

Abstract

A structural part for automotive applications, the structural part comprising at least one region or layer, the at least one region or layer comprising a consolidated layer of irregularly arranged unidirectional UD segments, the unidirectional UD segments comprising unidirectional fiber tufts at least partially bonded to adjacent segments.

Description

Technical Field

[0001] This invention relates to an impact protection plate or panel for battery-electric vehicles, and a method for producing such sheets or laminates. Background Technology

[0002] Automotive suppliers protect the lower area of ​​the battery casing, which holds the traction battery, beneath the vehicle using impact protection plates. Impact events that could damage or puncture the battery casing can lead to serious fire incidents, also known as runaway incidents, which could severely endanger any passengers and bystanders.

[0003] Current solutions are based on thick metal plate structures; however, these solutions have the drawback that impacts with stones or obstacles on the road surface damage the material and increase its fatigue. Repeated impacts can lead to severe deformation of the parts.

[0004] Unidirectional (UD) tapes are used in many industries to increase the stiffness of parts, thereby enhancing the toughness of parts or surfaces. UD tape is a thin material containing a large number of continuous filaments arranged in a unidirectional manner before being embedded in a thermoplastic matrix, hence its name. Because these tapes contain unidirectional filaments or fibers, they are typically laid in multiple layers, changing direction by, for example, 90° between layers, generally referred to as cross-layouts. The thermoplastic material used as the matrix can be one of polypropylene, polyamide, polyester, or high-density polyethylene, as well as copolymers and mixtures of all of the above. The continuous filament material can be glass, carbon, or a natural-based material.

[0005] Multiple UD strip layups can form sheets or laminates for subsequent shaping of the final part. The disadvantages of UD strips include reduced lamination with other surfaces and difficulty in deep drawing or forming three-dimensional shapes. Molding can be difficult and can cause stress within the continuous long strip, leading to shape distortion.

[0006] Furthermore, at least some scrap from the UD tape industry needs to be reduced. Because multi-layered materials are difficult to cut, sheets or laminates are often pre-cut to allow for better part shaping. Therefore, many applications using UD tape generate waste that is difficult to recycle, such as punching waste, cutting waste, or roll tail waste. In the case of carbon fiber-based UD tape, the cost of carbon fiber makes recycling possible, even if it is possible to separate the carbon fiber from the matrix; however, this is not an attractive option for glass fiber-based UD tape.

[0007] The goal is to achieve better utilization of resources. Furthermore, there is a need to further optimize the molding process for sheets, laminates, or panels to provide sufficient impact protection, thereby expanding applications to more complex forms. Summary of the Invention

[0008] This objective is achieved by structural parts according to the independent and dependent claims, by methods of producing such structural parts, and by the use of such structural parts in automotive applications and battery-electric vehicles.

[0009] In particular, structural parts for automotive applications include at least one region or layer comprising a consolidation layer of randomly arranged unidirectional UD segments, each unidirectional segment comprising unidirectional fiber clusters at least partially bonded to adjacent segments.

[0010] Unidirectional (UD) tapes are continuous fiber-reinforced tapes of varying widths, comprising unidirectionally aligned reinforcing fibers, preferably glass fibers, embedded in a thermoplastic matrix. They are used to reinforce materials to increase the stiffness and / or toughness of materials or products. These tapes are produced in strip or tape form, but pre-laid UD tapes can also be used to reinforce parts. During the production of such tapes and / or pre-laid UD tape products, UD tape waste is generated, such as punching waste, cutting waste, or roll tail accumulation waste.

[0011] Fragments of UD strip scrap or segments cut from UD strip are defined as UD segments. Due to the origin of UD segments, unidirectionally aligned reinforcing fibers are maintained. Precise cutting of UD strip or UD strip scrap yields smaller segments with precisely aligned fibers of precise length, and generating layers from such segments creates orientation differences between adjacent segments within that layer or region.

[0012] UD tape is difficult to mold into a robust three-dimensional shape because continuous filaments cannot be significantly stretched and therefore are not easily molded well by compression. Surprisingly, by using UD segment layers, these segments can slide against each other and easily form bends, while the long fibers maintain the integrity and stiffness of the layer or product thus produced.

[0013] These segments can be substantially the same size or different. For example, segments from different batches with different average sizes can be intentionally combined to cover a larger area or a larger bend.

[0014] UD segments can be obtained by shredding or cutting multiple UD strips or UD strips into smaller segments, known as segments. These segments can be formed into any shape that is advantageous for this purpose, such as circles, squares, or irregular shapes.

[0015] One advantage of using shredded or cut UD tape is that the fibers are pre-oriented within the fragments, so that they locally form bundles of fibers that are roughly parallel to each other in one direction.

[0016] Therefore, by generating layers of segments, where the segments are oriented adjacent to each other and partially overlap, the glass fiber bundles are randomly oriented and contribute to the generation of a more isotropic material, i.e., a more constant flexural stiffness above the surface of the layers. This differs from other short or long fiber-reinforced materials produced by injection molding or D-LFT processes, where the material is forced to flow and fill the mold cavity during the molding process. As a result, fiber orientation is controlled by the material flow, in such a way that most fibers are aligned parallel to the direction of material flow, leading to a decrease in mechanical properties in the vertical direction. Furthermore, unlike continuous filaments, because the movement of the fiber bundles is unrestrained, they are able to migrate within the material layers during molding.

[0017] The fiber length depends on the overall size of the fragment, particularly its length along the glass filament direction. When using cross- or multi-layered fragments, the length in any direction should preferably be at least 10 mm, preferably between 20 and 100 mm, and more preferably between 25 and 60 mm. All lengths are ±10%, as fragment cutting can be imprecise, especially when using scrap, where up to 15% of the fragments may be formed from smaller scraps or pieces. However, these can be beneficial for filling gaps and achieving a more uniform layer. For the same reason, combinations with oversized fragments may also be advantageous for certain locational requirements within the part structure.

[0018] The UD segment may have a length of at least 50 mm + / - 10%, preferably at least 70 mm + / - 10%, parallel to the long fiber direction, such that the fibers of the UD segment have a length of at least 50 mm + / - 10%, preferably at least 70 mm + / - 10%.

[0019] The fiber content of the UD fragment can be higher than 20% (by weight), preferably higher than 40% (by weight), and even more preferably higher than 60% (by weight).

[0020] UD fragments can be irregular in shape and size, for example, with a maximum size of 50 × 50 mm. These fragments can be pressed into a bonded sheet, for example, using compression or vacuum molding, to produce a laminate with randomly oriented, discontinuous glass fibers; however, this laminate is organized in localized areas where the fibers are arranged in essentially parallel patterns (where the original UD fragments were located). Additional resin may not be required to manufacture sheets solely from the UD fragments.

[0021] Preferably, segments with the same or chemically compatible resins are mixed. Although the fibers in the matrix may be different, glass and carbon fiber reinforced segments, for example, can be combined according to the properties required for the final part to be formed from the random UD segments.

[0022] Cross-laid laminates have two UD strip layups oriented at 0 / 90 degrees, and multiaxial UD laminates have at least two UD strip layups oriented at different angles in all orientations, including but not limited to 0 / 90 degrees.

[0023] Alternatively, the segments can be made from cross-lays or multi-lays of material that already includes multiple UD strip layers.

[0024] In a preferred embodiment, larger UD segments are formed in a laminate and the material is cut into segments after being placed in a mold and before one or more layers are applied on top.

[0025] The UD fragment comprises at least one layer of parallel reinforcing fibers embedded in a thermoplastic matrix, wherein the fibers in each layup are arranged substantially in a direction substantially parallel to the surface of the fragment. Preferably, the thermoplastic matrix is ​​one of polypropylene, polyamide, polyester, or high-density polyethylene, as well as copolymers and mixtures of all the above materials. Preferably, at least a major portion of the UD fragment used is based on the same or similar base material. Since the UD fragment may preferably be derived from recycled or regenerated sources, a small amount of contamination may occur without departing from the invention.

[0026] Preferably, the UD segment comprises glass fibers or carbon fibers in a polypropylene-based matrix. UD segments containing glass fibers can be combined with UD segments containing carbon fibers.

[0027] The unidirectional fiber-reinforced segments used may comprise more than one layup, arranged as a cross-lay with fiber orientations in adjacent layups at 0° and 90° angles, and / or arranged as a multi-layup with fiber orientations in adjacent layups at any angle between 0° and 90°. Employing multi-layup UD segments can further optimize the isotropic behavior of the monolayer in bending tests in all directions of the structural part's plane.

[0028] UD segments are obtained by cutting single-layer or multi-layer UD tape, or UD tape scrap containing such tape, into dimensions such that most fibers within the segment have a fiber length of at least 10 to 50 mm. With single-layer tape, this allows UD tape to be cut into segments of preferred lengths, whereby the width can be determined by the width of the UD tape used. In the case of cross-lay or multi-lay tape, the UD segments will be substantially closer to a circular or square shape to ensure appropriate fiber length.

[0029] UD segments are defined as unidirectional long fiber segments embedded in a matrix, wherein the fibers are oriented in the plane of the segment.

[0030] UD segments can be coated or sprayed with thermoplastic adhesives to further optimize adhesion between the segments and any available adjacent layers. Alternatively, they are premixed with adhesive powder to further optimize bonding and / or movement to the final location, which can be an advantage, particularly in more complex three-dimensional shapes. Preferably, the adhesive used is the same as or equivalent to the matrix material used in the UD segments.

[0031] By using multiple UD segments in a region or layer, a more flexible yet resilient material can be obtained.

[0032] In one aspect of the invention, a consolidation layer or region formed by randomly arranged cut unidirectional strip segments at least partially bonded to adjacent segments can be combined with at least one long fiber reinforced thermoplastic (LFT) composite layer comprising a thermoplastic polymer matrix and discontinuous reinforcing fibers with a length-to-diameter aspect ratio greater than a critical aspect ratio.

[0033] Unlike UD tapes or UD segments, the reinforcing fibers in LFT composites are arranged in a random manner, and due to the manufacturing process, the fiber lengths can vary over a wider range, with most fibers being shorter than those in UD segments.

[0034] Preferably, LFT materials are used based on the D-LFT process, in which glass filaments or tows are fed into an extruder in the form of continuous filaments and mixed with a heated thermoplastic matrix. Through the action of the extruder, the tows are broken into segments with a certain fiber length range. Preferably, the fiber length in the LFT is in the range of 10-25 mm. Depending on the extruder used, fiber lengths of less than 10 mm or up to 50 mm, preferably up to 100 mm, can be achieved. Preferably, the maximum fiber length is between 10 and 50 mm. Preferably, the D-LFT process is used because, compared to other flow molding processes, the D-LFT process can consistently produce the longest fibers.

[0035] In pellet-based LFT processes, the initial length is already limited by the pellet length and is further reduced during the hot extrusion process, resulting in shorter fiber lengths and therefore poorer material properties. However, alternative pellet forms of short fibers in LFT pellets or matrices can be used locally or in combination with UD fragments to improve the flowability of UD fragments, for example, in larger ribs or protrusions.

[0036] Preferably, D-LFT with a fiber content between 20% and 35% (by weight) can be used. Due to mixing, the fibers are distributed in all directions within the layer and form a random arrangement. Based on the flow of the material, a preferred fiber orientation is obtained in specific flow regions. The combination of the D-LFT composite layer and the UD segment molded together in regions or layers ensures good bonding or even partial mixing of the two materials, while the more organized long fiber groups of the UD segment locally enrich the fiber-reinforced composite material, resulting in areas and / or overall impact protection and / or increased flexural stiffness. The combination of D-LFT material with a fiber content of 20-35% and UD segments with a fiber content of 60-80% allows for localized adjustment of the final fiber content in the part in the sense of fiber enrichment. The combination of D-LFT material (which allows the fibers to be oriented in the flow direction) and UD segments (where the fiber orientation is maintained to a certain extent and only moderately changed due to material flow) allows for the design of fiber orientation in specific regions of the part.

[0037] Surprisingly, by placing UD segments in areas planned to have protrusions, such as ribs or protrusions for mounting points, the UD segments can be melted and shaped, while LFT material can fill any gaps between the thus loosened UD segments and / or draw them into the flow of filling the protrusions. By moving the UD segments and / or the fibers held by these segments, locally stronger areas or overall stronger layers can be obtained. UD segments form layers that are less robust than UD strips but more versatile and stronger than LFTs. The UD segments locally increase the fiber content and the isotropy of the material, preferably with a local increase of at least 10%, preferably at least 15%, and the more the better.

[0038] The heat of the D-LFT composite material is sufficient to heat the UD segments to incorporate these segments into the D-LFT layer, or into the layer formed by the UD segments, or into the layer or region formed by these segments that have been heated prior to the molding step, for example by infrared heating or hot air.

[0039] Any combination of at least one UD tape layup and / or D-LFT base layer with UD segment layers and / or regions falls within the scope of this invention. More preferably, all three materials can be used in combination.

[0040] The matrix material used for UD segments, UD tapes, and / or LFTs may contain any commonly used adhesives for these materials, such as antioxidants, and / or coupling agents, and / or adhesives and / or mineral fillers that blacken the parts. Preferably, they all have the same matrix base, preferably polypropylene, and glass or carbon as the main fiber, wherein the fibers may differ between the materials used.

[0041] Examples of some preferred combinations will be disclosed, but are not limited to possible combinations that are not discussed in detail but are clear to those skilled in the art from the disclosure.

[0042] In a preferred embodiment, an impact protection panel for automotive applications is provided, comprising a sandwich structure having at least a first layer and a second layer, the first and second layers comprising at least one UD strip layup and at least one thermoplastic core layer formed of a thermoplastic matrix material and chopped glass fibers, wherein the core layer is located between the first and second layers to form the sandwich structure. The impact protection panel further comprises at least one layer formed of shredded UD strip fragments aligned in a random order, the layer at least partially overlapping adjacent fragments to form a substantially closed layer. Preferably, the at least one layer may be located between the UD strip and the core layer, or on the surface of the core layer facing away from the UD strip layup layer, or on top of the UD strip layer. The core layer is preferably formed by D-LFT.

[0043] Surprisingly, the layer formed from cut UD strip fragments (hereinafter referred to as the UD fragment layer) is more flexible during molding than the continuous filaments in the UD strip, while the core matrix and glass fibers are able to move through the UD strip structure and flow into the interior of the protrusions to fill the cavity. By using UD fragments, more and longer glass fibers than the core material can be generated, at least in localized areas. These glass fibers are still able to migrate sufficiently and also fill extended areas, such as bead or rib structures bridging the UD strip and core material, resulting in a more uniform distribution of glass fibers throughout the structure and improving the stiffness and toughness of the part under impact.

[0044] D-LFT stands for Direct Long Fiber Thermoplastic (D-LFT), a long-fiber thermoplastic material in which glass fibers are directly incorporated into the extruder in the form of tows and cut as part of the extrusion action to generate fiber fragments mixed within the thermoplastic material.

[0045] Conventional LFT uses a similar process, but is based on premixed material cut to its maximum length, so the fiber length depends on this pre-cut material, and is usually sold in granular form of LFT, which is called granular long fiber thermoplastic (LFT).

[0046] By combining UD segments with LFT, fiber length and fiber volume fraction can be locally increased, thereby improving the mechanical properties of the produced parts.

[0047] Any automotive part that requires structural integrity can benefit from a base core layer and at least one UD segment layer. The UD segment layer can be formed from multiple UD segments that are partially stacked on top of each other to form a two-dimensional sheet or layer structure.

[0048] Structural parts or structural panels or 3D molded parts made of the materials according to the invention can be used as body bottom panels or covers, engine bottom panels or covers, dashboards or panels between the engine or motor area and the passenger compartment, floor panels, panels for lifting the interior floor of a vehicle in a transport vehicle, parcel racks, buffers, spare tire slots, battery casings, battery brackets, battery covers, and impact protection plates.

[0049] Possible methods for manufacturing the material according to the invention may include the following steps.

[0050] A layer or region forming UD segments, wherein multiple UD strip segments are randomly laid out and / or stacked to form a layer or region of desired thickness or desired thickness variation. Preferably, the layer or region is preheated, for example, with infrared light or hot air.

[0051] Alternatively, an additional adhesive in solution or powder form may be applied between segments or onto the surface of the layer. Alternatively, the segments may be mixed with the adhesive before the layer is fabricated. The adhesive can help bond and / or seal any gaps between UD segments.

[0052] In one variation, the layer is laid with gaps to facilitate LFT flow through the layer on a dedicated area. Alternatively, the density of the UD segments can be increased or decreased to guide the LFT along a preferred direction during molding.

[0053] This layer can be prepared outside the mold and ultimately pre-bonded before being introduced into the mold. Alternatively, the layer or region can be prepared directly inside the mold or on top of a prepared layer.

[0054] This layer or area can be combined with additional layers as needed and is thermoformed to form the final product.

[0055] In a product having a combination of at least one irregularly arranged UD segment layer and LFT layer, when the mold is closed, the LFT material can mix with the UD segments and partially move the fibers within the UD segments to form a new composite material that fills the mold, particularly any protrusions in the form of ribs, beams, or domes.

[0056] Surprisingly, LFT material is known for its good moldability, but it forms a weakness when discussing impact protection and fracture strength. This material, combined with local reinforcement or fiber enrichment of fiber bundles derived from UD fragments, increases the overall strength and impact resistance of parts, especially any mounting dome or mounting area.

[0057] The direct LFT (D-LFT) process, known in the art, is a preferred method for the base material or core material of this invention. It includes a first twin-screw extruder to obtain a first mixture, which is preheated and mixed to form a first extrudate. This extrudate is fed into a second extruder. A continuous glass filament, provided in roving form on a yarn bobbin, is drawn into the second extruder by the flow action of the first extrudate from the first extruder. In the second extruder, the continuous filament is cut into coarse segments with an average size between 10 and 25 mm of the resulting fiber volume and mixed into the extrudate.

[0058] The first mixture can be a matrix mixture, such as polypropylene, preferably free of glass fibers. This will ensure good mixing of the matrix and the adhesive used, while maintaining low energy requirements for mixing and melting.

[0059] The second mixture will be a matrix mixture, such as polypropylene, with a glass fiber concentration preferably of 60-70%. This mixture does not necessarily require a twin-screw extruder; a single-screw system for the melt mixture is sufficient. This mixture can be provided in the form of pre-formed granules or rods and requires only melting and homogenization before being supplied to the first extrudate and continuous glass filament roving.

[0060] Surprisingly, in the combination of UD tape, UD segments, and D-LFT material, D-LFT can be pushed through the UD tape and mixed with the UD segments, thereby partially encapsulating the UD segments and / or the fiber bundles within these segments, reinforcing the resulting protrusions.

[0061] Preferably, the UD strip layup used may be pre-cut to facilitate LFT and / or guide flow. In one embodiment, at least one UD strip layup forms a layer and is cut, perforated, or slid into an alternating pattern to form a flexible mesh. Attached Figure Description

[0062] Figure 1 It is a layer of irregular UD fragments according to the present invention.

[0063] Figure 2 A and Figure 2 B is an example of a layer of at least one UD segment according to the present invention in different combinations.

[0064] Figure 3 and Figure 4 This is an example of a region containing at least one UD segment in a protrusion according to the invention.

[0065] Figure 5 A and Figure 5 B is an example of a variation of a dome or rib that includes an irregular segment of the UD segment according to the invention. Detailed Implementation

[0066] Figure 1 Cross-sectional view A and top view B schematically illustrate a region or layer 1 formed by segments 2, 3, and 4 of randomly arranged UD strip. During layer formation, the segments are substantially arranged in the plane of the segment surface (indicated by double arrows above the surface); however, some segments may have an orientation in another direction outside the plane. The region or layer is preferably formed by more than one segment stacked on top of at least one other segment, such that, after forming, a layer with randomly arranged unidirectional clusters of long glass fibers is formed. For example, a segment 3 may have clusters of glass fibers represented by lines perpendicular to the direction of the glass fiber clusters, as indicated by dots in segment 4. Figure 1 B illustrates this effect from the top view, while in the actual part, the orientation may also change in the third dimension, tilting upwards or downwards.

[0067] After molding and / or thermosetting the region or layer, the matrix melts and then re-cures, thereby at least partially reducing the boundaries between adjacent initial segments; however, the unidirectional fiber clusters within the segments remain substantially together. Depending on the mold and pressure used, the clusters can move substantially together to a new location and / or orientation, thereby reinforcing the entire part through the enrichment of long glass fibers. Thus, randomly oriented UD segments have been used, which may generate new layers or parts. This layer or part can be used alone or in combination with at least one additional layer.

[0068] exist Figure 2 A to Figure 2 In C, Figure 1 The layer described herein, and according to the invention, is combined with at least one additional layer.

[0069] For example, in Figure 2In step A, a random UD fragment layer 1 is combined with a long fiber thermoplastic (LFT) layer 5, which comprises long fibers randomly arranged in a thermoplastic matrix. The UD fragment layer can be pre-prepared, or a loose layer of random UD fragments can be layered on the stacked surfaces, with the LFT extrusion positioned on top of and / or beside the UD fragments, and the material molded. Optionally, according to the invention, another layer or region 1' can be locally constructed using randomly arranged UD fragments. Preferably, to prevent warping, the material is placed on both surfaces of the LFT layer, forming a sandwich.

[0070] exist Figure 2 In B, the LFT core layer 5 is combined with at least one UD strip layup stacked on one surface of the LFT core layer, while the other surface includes at least one UD segment layer, optionally combined with at least one UD strip layup. By placing the UD segment layer on one side of the LFT core layer, more complex shapes or structures can be more easily fabricated on that portion of the surface without sacrificing strength.

[0071] By combining UD strips with LFTs and UD segments at least partially, the required strength and moldability of 3D molded parts can be finely tuned. For example, in the case of impact protection panels under a vehicle, the road-facing surface is most vulnerable to impacts from flying objects (such as stones) or road objects (such as curbs). Therefore, preferably, at least one entire UD strip layup can be used on this side. The LFT facing the bottom of the vehicle (e.g., the battery box or optionally forming part of the battery box), the side facing the battery, can be formed into complex 3D shapes, including mounting plugs and / or ribs. Surprisingly, it has been found that using UD segments allows for more precise molding of such protruding areas without sacrificing strength. This is because the segments can move the LFT through compressive forces, thereby displacing the UD segments, resulting in areas with higher strength compared to using the LFT alone.

[0072] Figure 2 C shows an example of such a part, which has a high rib 8 on one side, usually facing the car, while the other side is basically flat.

[0073] Preferably, the structure is constructed based on a combination of at least one UD strip layup as layer 6 on the flat surface side of the part, an LFT core, and a surface layer of UD strip segments, which is formed into ribs by the action of the LFT during compression molding, the ribs for example holding the battery cell in place. Optionally, at least one UD strip layup may be placed between the LFT core layer and the irregular UD segment layer.

[0074] Figure 3An example of area application is shown, where UD segments 1 are applied only locally and irregularly, for example, in this case, in the area between two layers of at least one UD strip layer 6, such as the area for later drilling. During compression molding, these segments will be partially fused with the LFT material 5 to form a reinforced area that is stronger than a single LFT. Another surface may include at least one UD strip layup 6.

[0075] Because it is difficult to form protrusions 7 using UD strip layups, and LFT alone would create the weakest point, the combination with locally applied UD segments locally strengthens the part and may better form protrusions. The essentially unidirectional long fiber clusters derived from UD segments improve the local strength of the part through fiber enrichment, which is impossible to achieve using UD strip or LFT material layups alone. This application method can improve the strength of areas that pass through or are mounted, or increase the strength around integrated metal or plastic parts (such as washers or threads).

[0076] Figure 4 A schematic cross-section of the part is shown, wherein, for example, as shown... Figure 3 The diagram illustrates the process during molding of the protrusion. The matrix of all layered materials melts and is compressed together to form the final shape. The matrix of the LFT is extruded between and through the UD strip layups and pushed into the surface layer formed by the UD segments. Through the movement of the LFT, which comprises randomly arranged long fibers (arrows), the unidirectional fiber bundles of the UD segments move at least partially into the protrusion, increasing the fiber content of the LFT and further strengthening the protrusion and its connection to the body of the part.

[0077] Figure 5 A and Figure 5 B shows the same Figure 3 and Figure 4 A similar situation exists, however here the region not only has increased thickness but also forms a dome-shaped structure, typically used for connection points. Figure 5 In A, a variation is shown that has a continuous UD strip layup around the dome, and fiber enrichment is achieved using irregular UD segments in the top region 7 of the dome shape. In this first variation, the UD strip at the lower surface of the dome constrains the forming process and limits the final possible dome size. Figure 5 In a variation of B, the UD strip layup is locally cut to form strips or segments that can move upwards during molding to form protrusions. The protrusions can be circular domes, but hollow ribs are also possible. This method enhances the strength of the sides of the protruding domes or ribs by using irregular UD segments.

[0078] An example of a part according to the invention may be an impact protection panel comprising a sandwich structure having at least a first layer and a second layer, wherein the first and second layers comprise at least one UD strip layup and a thermoplastic core layer comprising at least a thermoplastic matrix material and chopped glass fibers, wherein the core layer is located between the first and second layers to form the sandwich structure, characterized in that the impact protection panel comprises at least one layer or region formed of cut UD strip segments aligned in an irregular order, the strip segments at least partially overlapping adjacent segments to form a substantially closed layer or region.

Claims

1. A structural part for automotive applications, the structural part comprising at least one region or layer comprising a consolidation layer of randomly arranged unidirectional UD segments, the unidirectional segments comprising unidirectional fiber clusters at least partially bonded to adjacent segments.

2. The structural component for automotive applications according to claim 1, wherein, The unidirectional segment includes at least one parallel glass fiber layup embedded in a thermoplastic matrix, wherein, in each layup of the segment, the glass fibers are arranged substantially in one direction, which is substantially parallel to the main plane of the part.

3. The structural component according to claim 2, wherein, The unidirectional segment comprises one or more plies arranged as cross-lays at angles of 0° and 90° to the fiber orientations of adjacent plies, and / or as multi-lays arranged at any angle between and including 0° and 90° to the fiber orientations of adjacent plies.

4. The structural part according to any one of the preceding claims, wherein, The segment is cut to a certain size such that most of the fibers within the segment have a fiber length of at least between 10 and 200 mm, preferably between 10 and 100 mm.

5. The structural part according to any one of the preceding claims, wherein, The thickness of the region or layer including the segment can be varied.

6. The structural part according to any one of the preceding claims further includes a fiber-reinforced thermoplastic base layer comprising irregularly arranged long fibers embedded in a thermoplastic matrix.

7. The structural component according to claim 6, wherein, The majority of the long fibers in the base layer have a fiber length >10 mm and <100 mm, preferably >50 mm or more, and preferably at least 80% of the fibers are between 10 and 25 mm.

8. The structural part according to claim 6 or 7, wherein, The long fibers are glass fibers.

9. The structural part according to claim 6, 7 or 8, wherein, The glass fiber content of the base layer is between 20% and 40% by weight.

10. The structural part according to any one of the preceding claims further includes at least one reinforcing layer comprising at least one unidirectional strip layup that at least partially covers at least one layer or region of the structural part.

11. The structural part according to claim 10, wherein, The unidirectional tape comprises continuous filament glass fibers embedded in a matrix, which is preferably a matrix based on polypropylene or a polypropylene copolymer or a mixture of both.

12. The structural component according to claim 10 or 11, comprising at least one base layer covered with a reinforcing layer on both surfaces, the reinforcing layer being formed of 1 to 30 unidirectional strip layups, preferably 4 to 25 unidirectional strip layups, further comprising at least one region having a UD segment, wherein, The UD segment is at least partially topographically formed as at least one protrusion, such as a rib, bead, beam, hollow rib, or dome.

13. The structural part according to claim 10 or 11, wherein, The material is at least partially formed into at least one protrusion, such as a rib, bead, beam, hollow rib, or dome, the glass fiber content of which is greater than the glass content of the base layer, preferably at least 10%, and preferably at least 40%.

14. The structural part according to claim 12, wherein, The at least one protrusion is formed by a combination of at least the base material and the UD segment, wherein the parallel fibers of the UD segment are at least partially moved into the protrusion.

15. An impact protection panel, comprising a sandwich structure having at least a first layer and a second layer, wherein, The first and second layers comprise at least one UD strip layup and a thermoplastic core layer comprising at least a thermoplastic matrix material and chopped glass fibers, wherein the core layer is located between the first and second layers to form a sandwich structure. The impact protection panel comprises at least one layer or region formed by cut UD strip segments aligned in an irregular order, the strip segments at least partially overlapping adjacent segments to form a substantially closed layer or region.

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