A sandwich panel having a unidirectional composite tape and its production process

Abstract

The present invention enables the production of optionally wide thermoplastic sandwich panels having a composite skin in 0° / 90° unidirectional tape laying-up. The composite skin can be composed of a thermoplastic film or sheet material. The present invention enables the rapid production of thermoplastic honeycomb sandwich panels of different widths. The thermoplastic film or sheet is preferably joined / layered to the honeycomb core by thermoplastic welding.

Description

Technical Field

[0001] The present invention relates to optionally wide thermoplastic sandwich panels having a composite skin in 0 / 90° unidirectional tape lay-up, and to their production. The composite skin can be composed of a thermoplastic film or sheet material. The present invention relates to the rapid production of finished thermoplastic honeycomb sandwich panels of different widths. The thermoplastic film or sheet is preferably joined / layered to the honeycomb core by thermoplastic welding. The thermoplastic film or sheet is used as a reinforcing material and is preferably joined / layered to the honeycomb core by thermoplastic welding. The honeycomb core is preferably formed from a plurality of polygonal cells arranged in an array, and each polygonal cell has side cell walls extending between the vertices of each polygonal cell.

Background Art

[0002] Background The in-line lamination of a continuously reinforced thermoplastic composite skin to a thermoplastic honeycomb core results in a cost-effective sandwich panel that provides stiffness and strength at minimum weight for use in a wide range of applications in many industries. Continuously produced thermoplastic honeycomb cores, such as the folded honeycombs described in WO 2006 / 053407, enable significant cost savings in the mass production of such sandwich panels.

[0003] Typically, in a 0° / 90° layup, two layers of a woven thermoplastic composite skin or unidirectional fiber reinforced thermoplastic tapes (UD tapes) are applied to each major surface of a honeycomb core to create a sandwich panel having high flexural rigidity and strength in both major directions of the panel. U.S. Patent Application Publication No. 2020 / 164624 (Wismans, 2018) describes a symmetric laminate. U.S. Patent Application Publication No. 2008 / 047121 (Rohr, 2008) presents a method for joining composite honeycomb panel sections. U.S. Patent Application Publication No. 2022 / 001643 (Huaping, 2022) describes a further method for joining honeycomb cores before applying skins to the joined honeycomb cores. Summary of the Invention Problems to be Solved by the Invention

[0004] Continuously produced thermoplastic honeycomb cores enable the in-line production of such sandwich panels. The two layers of thermoplastic tape are typically laminated together within a double-belt laminator and wound up to form a skin laminate. Such a laminate is then laminated, for example in-line, on both sides of the honeycomb core during the production of the continuously produced thermoplastic honeycomb core to form a composite skin. In this in-line process, the width of the resulting sandwich panel is limited by the width of the honeycomb production line and the width of the laminate and laminator that are available. Therefore, the honeycomb core needs to be produced before lamination onto the honeycomb core. This can increase the inventory that has to be stored to be available at any time to meet specific customer requirements. Means for Solving the Problems

[0005] Summary of the Invention The object of embodiments of the present invention is to enable the production of optionally wide thermoplastic sandwich panels having a composite skin in a 0° / 90° unidirectional tape layup. The composite skin can be composed of a thermoplastic film or sheet material. Embodiments of the present invention enable the rapid production of thermoplastic honeycomb sandwich panels of different widths. The thermoplastic film or sheet is used as a reinforcement and is preferably joined / layered to the honeycomb core by thermoplastic welding.

[0006] The honeycomb core is preferably formed from a plurality of polygonal cells arranged in an array, each polygonal cell having lateral cell walls extending between the vertices of each polygonal cell. The honeycomb core is preferably a folded honeycomb core. Preferably, each polygonal cell is bounded on two sides by a covering layer plane, and the lateral cell walls of each polygonal cell form a polygonal ring. For half of the cells along one edge of the honeycomb core, the upper or lower part of the cell is open, and along the opposite edge, for the other half of the cells, the upper or lower part is closed. Thereby, at each side edge of the reinforced honeycomb core, the cells from one reinforced core have an open upper part and can be cut in half, and a trimming operation can be performed so as to be joined to the cells from an adjacent reinforced core, and the cells have a closed upper part that can be cut in half. These trimmed edges can be pressed together at a specific pressure to provide reinforcement at the joint between two honeycomb core sheets or honeycomb panels.

[0007] Another object of embodiments of the present invention is to enable the production of optionally wide thermoplastic honeycomb panels having a thermoplastic composite skin in a 0° / 90° reinforcement layup, which is based on the use of narrower honeycomb core sheets joined without weak spots or without significant weakening at the joints of separate honeycomb cores or reinforcement joints.

[0008] The advantage of the present invention is that a separate lamination step for creating a 0° / 90° laminate uses further processing of a reinforced honeycomb core having 0° reinforcing layers on both sides of a honeycomb core with a production direction rotated 90°, to re-apply a second reinforcing layer at 0° with respect to the new production direction on both sides of the honeycomb core. Thereby, first and second laminates having a 0° / 90° layup are obtained.

[0009] The separate lamination steps can be performed at different locations. This has the important advantage that the small-scale production of honeycomb cores with a first 0° reinforcing layer laminated thereon can be rapid and cost-effective, and small panels can be easily transported. The second lamination step for forming a wider sandwich panel with a final 0° / 90° composite laminate skin can be performed locally, for example, where these panels are joined to a tractor-trailer box or for other applications.

[0010] One or more objects are achieved, according to embodiments of the present invention, by the production of an intermediate panel having single-ply UD reinforcing skins on both sides of a honeycomb core in the 0° direction along the production direction of the continuously produced honeycomb core. An additional UD reinforcing layer laminated in the 0° direction after a 90° rotation of the machine direction of the process is applied to the intermediate panel. Preferably, this includes reinforcement at the joints between intermediate panels. This reinforcement can include one or more of the following.

[0011] Overlap, and / or Interpenetration of adjacent intermediate panels, or Use of an adhesive layer or loops at the joints between adjacent intermediate panels.

[0012] All of these methods can form strong joints. At this time, the core density in the small area where two intermediate panels are joined is higher than the core density of the remaining part of the intermediate panel. This ensures good support of the outer layer (sometimes called the "skin") and complete core-skin bonding in the area of the joint.

[0013] Embodiments of the present invention provide a reinforced honeycomb sandwich panel, which has edges and a plurality of honeycomb core sheets having a first core density, and a first skin layer having 0° fiber reinforcements laminated on both sides of each of the plurality of honeycomb core sheets to form a laminated reinforced honeycomb core sheet, and at the connection between the laminated reinforced honeycomb core and the first skin layer having a 0° fiber reinforcement layer above and below the position where the edges of the honeycomb core are joined, in order to create an area of a second core density higher than the first core density, butt joints between the edges of the respective laminated reinforced honeycomb core sheets at parallel locations of the edges of the laminated reinforced honeycomb core sheets such that the edges overlap each other, or penetrate each other, or are deformed, and a second skin layer having 90° fiber reinforcements on both sides of the laminated reinforced honeycomb core above and below the 0° fiber reinforcement layer to form a laminated reinforced honeycomb sandwich panel.

[0014] Embodiments of the present invention provide a reinforced honeycomb sandwich panel, which has edges and a plurality of honeycomb core sheets having a first core density, and a first skin layer having 0° fiber reinforcements laminated on both sides of each of the plurality of honeycomb core sheets to form a laminated reinforced honeycomb core sheet, and at the connection between the laminated reinforced honeycomb core sheet and the first skin layer having a 0° fiber reinforcement layer above and below the position where the edges of the honeycomb core are joined, in order to create an area of a second core density higher than the first core density, butt joints between the edges of the respective laminated reinforced honeycomb core sheets at parallel locations of the edges of the laminated reinforced honeycomb core sheets such that the edges overlap each other, or penetrate each other, or are deformed, and a second skin layer having 90° fiber reinforcements above the 0° fiber reinforcement layer on both sides of the laminated reinforced honeycomb core sheet to form a laminated reinforced honeycomb sandwich panel.

[0015] Embodiments of the present invention provide a method for continuously producing laminated reinforced honeycomb sandwich panels from a plurality of honeycomb cores as input materials, each of the honeycomb cores having two opposing major surfaces, one on each side of each of the honeycomb cores, and further aspects of the method are Applying and laminating a first skin layer having a first 0° fiber reinforcement layer to the honeycomb core by thermoplastic welding, such that one first skin layer is laminated on each major surface of each of the honeycomb cores, and the first 0° fiber reinforcement layer has fibers extending in a first machine direction; applying and laminating Cutting the honeycomb core to form first and second intermediate panels having continuous straight edges Trimming the opposing edges of the first and second intermediate panels to expose the edge joints Rotating the first machine direction by 90° without rotating the intermediate panels, thereby obtaining a second machine direction; rotating Joining the first intermediate panel to the second intermediate panel in continuous production to form a joint of the first and second intermediate panels having reinforcement at the joint of the first and second intermediate panels, the reinforcement being Overlapping or interpenetrating the edges of adjacent intermediate panels, or using an adhesive layer or adhesive loop for butt-joint bonding the first intermediate panel to the second intermediate panel at the butt joint, and optionally applying an in-line compressive force to the edge joints of the first and second intermediate panels, or completing an adhesive butt joint, including one or more of these; joining Applying and laminating a second skin layer having a second 0° fiber reinforcement to the joined first and second intermediate panels by thermoplastic welding to form a laminated reinforced honeycomb core, such that one second skin layer is laminated on each major surface of the first and second intermediate panels, and the fiber direction of the second skin layer is 90° with respect to the fiber direction of the first skin layer on each laminated reinforced honeycomb core; applying and laminating

[0016] Embodiments of the present invention provide an apparatus for continuously producing laminated reinforced honeycomb sandwich panels from a plurality of honeycomb cores as input materials, each of the honeycomb cores having two opposing major surfaces, one on each side of each of the honeycomb cores, and the apparatus includes a first conveyor for conveying the input material in a first machine direction to a laminator, a storage for storing a first skin layer which is a first 0° fiber reinforced layer, a laminator for laminating the first skin layer by thermoplastic welding to form a layered honeycomb core, wherein one first skin layer is laminated on each major surface of each of the honeycomb cores, and the first 0° fiber reinforced layer has fibers extending in the first machine direction, a cutter for cutting the layered honeycomb core to form first and second intermediate panels having continuous straight edges, a trimmer for trimming opposing edges of the first and second intermediate panels to expose edge connections, a second conveyor having a second machine direction that is 90° with respect to the first machine direction and for receiving the layered honeycomb core without rotating the layered honeycomb core, means for joining a first layered honeycomb core to a second layered honeycomb core in continuous production to form a joint of the first and second honeycomb cores having reinforcement at the joint of the first and second layered honeycomb cores, wherein the reinforcement at the joint includes one or more of overlapping or interpenetrating the edges of adjacent intermediate panels, or using an adhesive layer or adhesive loop for adhesively bonding the first intermediate panel to the second intermediate panel at the butting joint, and optionally applying an in-line compressive force to the edge connections of the first and second intermediate panels, or completing the adhesive butting joint, a second storage for storing a second skin layer having a second 0° fiber reinforced layer with respect to the second machine direction, the application being made on each side of each of the layered honeycomb cores, A second laminator for laminating a second skin layer by thermoplastic welding to form a layered honeycomb core, wherein one second skin layer is laminated on each major surface of each of the layered honeycomb cores, and the second 0° fiber reinforcement layer has fibers extending in a second machine direction, the second laminator.

[0017] For half of the cells along one edge of the intermediate panel or honeycomb core sheet, the upper or lower part of the cell is preferably open, and along the opposite edge, for the other half of the cells, the upper or lower part is closed. Thereby, at each side edge of the reinforced honeycomb core or intermediate panel, the cells from one reinforced honeycomb core sheet or intermediate panel have an open upper part and can be cut in half, and a trimming operation can be performed so as to be joined to the cells from an adjacent reinforced honeycomb core sheet or intermediate panel, and the cells of the honeycomb core sheet or intermediate panel have a closed upper part that can be cut in half. These trimmed edges can be pressed together at a specific pressure. Applying a joint of the first 0° fiber reinforcement layer where the honeycomb core sheets penetrate each other results in a locally higher core density at the joint and a substantial improvement in the support of the outer 90° UD layer at this critical location.

[0018] Embodiments of the present invention provide a reinforced honeycomb sandwich panel comprising the following. a) A honeycomb core, such as a folded honeycomb core, as shown in FIG. 14.

[0019] b) A first skin layer having a first 0° fiber reinforcement applied by laminating (e.g., thermoplastic welding) on both sides of the honeycomb core to form a honeycomb core sheet, wherein the 0° direction is with respect to the fiber reinforcement parallel to the first machine direction, i.e., the production direction, the first skin layer.

[0020] c) The butt joint or parallel location of the edge of the honeycomb core, having a 0° fiber reinforced layer where the edges of the reinforcing layer join, or the edges are arranged in parallel, or are laminated above and below a position where they penetrate each other (e.g., a few millimeters). Optionally, joints having a slight overlap of the 0° fiber reinforced skin layer are included within the scope of the present invention.

[0021] d) A second skin layer having 90° second fiber reinforcements on both sides of a honeycomb core sheet applied on top of a first fiber reinforced skin layer of 0°, wherein one second skin layer is laminated on each main surface of the honeycomb core sheet to form a further reinforced honeycomb core sandwich panel. Having a joint of the first UD0° layer at a location where the edges of the honeycomb core sheet penetrate each other provides reinforcement for the joint and results in a substantial improvement in the support of the outer 90° UD layer at this location.

[0022] Embodiments of the present invention are defined in the appended claims and further developed by the additional features of the dependent claims.

[0023] Definitions "Honeycomb core" relates to an array of honeycomb cells forming a sheet where the longitudinal axis of the cells is 90° with respect to the sheet. Such a honeycomb core can be manufactured as shown in FIG. 14.

[0024] "Honeycomb core sheet" is a honeycomb core having layers (also called skins) laminated to the core on both sides of the core.

[0025] "Intermediate panel" is a honeycomb core sheet whose main surfaces are laminated to fiber reinforced layers such as provided by UD tapes, and optionally, at least the cells at its edges are trimmed to provide connections.

[0026] The "UD tape" is a fiber-reinforced thermoplastic material in the form of a film or sheet that can be laminated (e.g., by thermoplastic welding) to a honeycomb core or another fiber-reinforced thermoplastic material in the form of a film or sheet. Such tapes are commercially available, for example, as follows.

[0027] https: / / thermoplasticcomposites.de / en / products / ud-tapes / https: / / www.profol.de / ud-tape-proud / . Tencate in California, USA, offers a UD tape called Cetex TC960 (formerly PMC / Baycomp CFRT® PP), which is a polypropylene-based thermoplastic unidirectional tape. This thermoplastic composite is designed for applications that require high impact resistance. The impact toughness of the glass fiber / polypropylene composite makes them ideal for use in truck bodies, vehicles, and vehicle enclosures.

[0028] The tapes are also commercially available, for example, from Sabic in Saudi Arabia. The "0° fiber-reinforced unidirectional tape" refers to a tape material reinforced by fibers extending along the tape. The "90° fiber-reinforced unidirectional tape" refers to an additional tape material reinforced by fibers that extend along the tape, but the tape is applied with fibers perpendicular to the fibers of the 0° fiber-reinforced unidirectional tape. "Cross-ply" refers to a layer of 0° fiber-reinforced unidirectional tape in which the fibers extend along the tape such that the fibers of the 0° fiber-reinforced unidirectional tape are at 90° to the fibers of the 90° fiber-reinforced unidirectional tape.

Brief Description of the Drawings

[0029]

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Figure 14

Mode for Carrying Out the Invention

[0030] Detailed Description of Exemplary Embodiments FIG. 1 shows a sandwich panel 10 having upper (7, 8, 9) and lower (4, 5, 6) inner 0° fiber reinforced unidirectional tapes (i.e., UD tapes) laminated, or more preferably, thermally welded in the production direction W of continuously manufactured honeycomb cores 1, 2, 3 (e.g., the W direction of the folded honeycomb core). The edges of the honeycomb cores 1, 2, 3 are parallel to the edges of the upper and lower inner 0° UD tapes 4, 5, 6, 7, 8, 9. These inner 0° UD tapes 4, 5, 6, 7, 8, 9 are cut in the length direction by a cut in the cross direction along with the cutting of the honeycomb cores 1, 2, 3. As shown in FIG. 1, the inner 0° UD tapes 4, 5, 6, 7, 8, 9 are at the same end as the honeycomb cores 1, 2, 3. The outer UD tape layers 10, 11 are continuous in the L direction and connect the honeycomb cores 1, 2, 3 and the inner 0° UD tape layers 4, 5, 6, 7, 8, 9 to a larger-sized sandwich panel. In the L direction, there are mechanical weaknesses 12, 13 between a finite number of honeycomb cores 1, 2, 3.

[0031] The honeycomb core can be made from a single sheet. The honeycomb core can be composed of a thermoplastic polymer selected from the group consisting of a thermoplastic polymer and / or a thermoplastic elastomer polymer, or a polyolefin, particularly polyethylene or polypropylene, a polyester, particularly polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate or polyethylene-1,2-furandicarboxylate, a polyamide, particularly polyamide 6 or polyamide 6,6, a polycarbonate, a polyether ketone, a polyether ether ketone, a polyether ketone ketone polyether, a polyether ester, a polyphenylene sulfide, a polyether imide, copolymers and mixtures thereof.

[0032] Figure 2 shows the layup and edges of different layers of the honeycomb sheet as viewed from / along the W direction.

[0033] To avoid or reduce the possibility that interruptions or gaps (caused by cutting and joining) between honeycomb cores 1, 2, 3 in the L direction lead to a reduction in shear performance, a reinforcing material 15 can be applied to all weak spots 12, 13 between honeycomb cores 1, 2, 3.

[0034] In Figure 3, the reinforcing material 15 is shown as being provided by a thermoplastic film 16, such as a thermoplastic adhesive film 17, which can apply an excess loop 18 between adjacent edges of the UD laminated cores 1, 2, 3 to ensure the transmission of shear forces in cores 1, 2, 3. The thermoplastic film 16 or the adhesive film 17 can be applied over the entire length of the UD tape, i.e., the upper and / or lower UD tapes, or over the entire length between the UD tape and the honeycomb core, on the upper and / or lower sides.

[0035] The reinforcing material 15 can be a thermoplastic or thermosetting adhesive film (less preferred), or it can be a thermoplastic coated metal, such as an aluminum layer that enables the bonding of the outer UD tape layer by induction heating of the aluminum layer.

[0036] Figure 3 shows how such a reinforcing material, such as the adhesive film 17, can sag naturally or be pushed between the spaced UD laminate cores 1, 2, 3, for example by pressure and heat, before the bonding process is completed.

[0037] Figure 4 shows an adhesive film loop 18 compressed between the intermediate panels of the honeycomb cores 1, 2, 3, which can bond the cores 1, 2, 3 to each other at a lower temperature and optionally bond the outer UD tape layers 10, 11 to the intermediate panels.

[0038] Figure 5 shows a sandwich panel production process 30 according to an embodiment of the present invention and the equipment therefor.

[0039] The input material 31 can be the product of in-line honeycomb core manufacturing (such as shown in FIG. 14), preferably of continuous in-line honeycomb core production as described and shown in WO 2006 / 053407, which is hereby incorporated by reference. The input material 31 can be a honeycomb core 32 manufactured by such a process, having honeycomb cells 33, for example an array of rectangular, square or hexagonal cells. The array can have columns 21, 22 and rows. Each polygonal cell 33 has lateral cell walls extending between the vertices of each polygonal cell 33, each polygonal cell 33 is bounded on both sides by a coating layer plane, and the lateral cell walls of each polygonal cell 33 are in the form of a polygonal ring. The first column 21 of FIG. 7a can be a cell closed at the top, and the second column 22 can be a cell open at the top. As shown in FIG. 7a, the first column 21 alternates with the second column 22. In FIG. 7a, one edge 23 of the polygonal core can be trimmed to have cells open at the top, while at the right edge 24, the polygonal core can be trimmed so that the cells are closed at the top. The honeycomb core is longitudinally trimmed during the production of the continuously produced honeycomb core to produce suitable edge structures 23, 24 and edge connections 25, 26, and the edge connections 25, 26 can be used to join two or more panels to each other. Alternatively, the trimming can be a method step of processing the honeycomb core 32 in process 30.

[0040] FIG. 7a schematically shows such a first trimmed honeycomb core 32. At the edge having reference number 23, the cells are trimmed so that the cells are open at the top and connection 25 is produced. FIG. 7a also shows such a second trimmed honeycomb core, where at the edge of reference number 24, the cells are trimmed so that the cells are open at the top and connection 26 is produced.

[0041] Such a honeycomb core 32 has in-plane dimensions that are much larger compared to the cell size. For example, the cell size can be 3 mm to 10 mm, while the width of the honeycomb core 32 can be, for example, 400 mm to 1200 mm in length of 2000 mm to 3000 mm.

[0042] Figures 7a, 7b, and 7c show a honeycomb core, for example, a 12 mm thick honeycomb core with a smaller cell size such as a 5 mm cell size. Honeycomb cores from different panels are arranged side by side. This can result in small gaps between the honeycomb core sheets, for example, if the cut at the edge is not completely straight. In Figure 7c, the honeycomb core sheets are shown penetrating each other.

[0043] Returning to FIG. 5, the width 34 of the honeycomb core 32 produced by in-line honeycomb core production 31 is generally smaller than the required width 35 of the final product. The final width 35 of the thermoplastic sandwich panel is obtained by cutting the honeycomb core 32 to length and rotating the machine direction by 90°. To achieve this, the honeycomb core 32 is conveyed by a conveyor such as a belt conveyor or a caterpillar (not shown) towards the laminator 38, in particular the calibrator and laminator 39. Before entering the laminator 38 or 39, heating or cooling can be performed, such as by infrared lamps, to bring the honeycomb core 32 to the correct processing temperature. The processing is continuous. Before reaching the laminator 38 or 39, the 0° UD tape 36 is unwound from a roll and applied to the upper surface of the honeycomb core 32, optionally using temperature and / or pressure. At the same time, the 0° UD tape 37 is unwound from a roll and applied to the lower surface of the honeycomb core 32, optionally using temperature and / or pressure. The reinforcing fibers of the OD tapes 36, 37 run in the machine direction, i.e., the machine direction is 0°. In the laminator 39, the lamination of the UD tapes 36, 37 is completed and the edges 23 and 24 can be trimmed, for example, to create edge connections 25 and 26. The honeycomb core 32 can be trimmed longitudinally. Alternatively, trimming can be a method step in processing the honeycomb core 31 in process 30. The honeycomb core 31 can be trimmed longitudinally during the production of the continuously produced honeycomb core 32 to produce suitable edge structures 23, 24 and edge connections 25, 26. This enables joining two or more panels together using the edge connections 25, 26. Alternatively, trimming can be a method step in processing the honeycomb core 31 in process 30. During or before and after processing in the laminator and trimmer 39, the intermediate panel 42 with UD tapes on both sides, which is the output of the laminators and trimmers 47, 49, is cut to length. This length results in the width 35 in the final product.

[0044] Next, the intermediate panel 42 is moved to a separate production line 50 that proceeds at 90° to the conveyor. By doing so, the machine direction is moved 90°, but the intermediate panel does not rotate.

[0045] The intermediate panel 42 here includes a honeycomb core 32 having UD tapes 36, 37 applied in the cross direction with respect to the new machine direction. Here, the first panel 42 is joined to a second identical panel 42 by arranging the first and second panels and the connecting portions 25, 26 side by side and placing them on each one panel 42 respectively. The connecting portions 25, 26 are joined together to join the first and second panels in the overlapping region. The intermediate panel 42 is conveyed towards a second laminator 43 by a conveyor such as a belt conveyor or a caterpillar (not shown). A 0° UD tape 44 is unwound from a roll and attached to the upper surface of the intermediate panel 42, optionally using temperature and / or pressure. At the same time, a 0° UD tape 45 is unwound from a roll and attached to the lower surface of the intermediate panel 42, optionally using temperature and / or pressure. The reinforcing fibers of the OD tapes 44, 45 proceed in the machine direction, i.e., the machine direction is 0°. Then, the joined panels are conveyed to the laminator 43, where the lamination of the UD tapes 44, 45 can be completed. A completed honeycomb sheet having a plurality of intermediate panels 42 with edge connections completed and cross UD tape reinforcements applied exits the laminator 43 with a width 35 that is larger than the width 34 of the honeycomb core 32, for example, 50% or more.

[0046] Figure 6 shows another embodiment of a method and apparatus for producing a sandwich panel. The method steps and apparatus are the same as those described with reference to Figure 5, except for the additional steps described below. Referring to Figure 6a, the input material can be the same product 32 as the in-line honeycomb core production 31 described with reference to Figures 1-5. The width 34 of the honeycomb core 32 produced by the in-line honeycomb core production 31 is generally smaller than the required width 35 of the final product. The apparatus, method, and equipment of this embodiment process optional additional reinforcing materials such as bonding layers, for example, a low melting point thermoplastic adhesive film 16. These bonding layers can also be a thermosetting adhesive film or a thermoplastic adhesive film or a thermoplastic coated aluminum layer that can enable the bonding of the outer UD tape layer by induction heating. Similar to Figure 3, in Figures 6a and 6b, the reinforcing material 15 is shown as being provided by a thermoplastic film 16, such as a thermoplastic adhesive film, that can apply an excess loop 18 between adjacent edges of the UD laminated cores 1, 2, 3 to ensure the transmission of shear forces in the cores 1, 2, 3. The thermoplastic film or adhesive film 16 can be applied over the entire length of the UD tape, i.e., the upper and / or lower UD tapes, or over the entire length between the UD tape and the honeycomb core, on the upper and / or lower sides.

[0047] The reinforcing material 15 can be a thermoplastic or thermosetting adhesive film (less preferred), or can be a thermoplastic coated aluminum layer that enables the bonding of the outer UD tape layer by induction heating of, for example, an aluminum layer.

[0048] Figure 6a shows how such a reinforcing material, for example, the adhesive film 17, can be allowed to hang naturally or be pushed further between the UD laminated cores 1, 2, 3 that are somewhat spaced apart, for example, by pressure and heat, before the bonding process is completed.

[0049] Figure 6a shows the adhesive film loop 18 compressed between the intermediate panels of the honeycomb cores 1, 2, and 3, which can bond the cores 1, 2, and 3 to each other at a lower temperature, and optionally bond the outer UD tape layers 10, 11 to the intermediate panel 42.

[0050] The advantage compared to a woven thermoplastic composite skin laminated from a 0° / 90° UD tape layer or a sandwich panel laminated with a composite skin is that in embodiments of the present invention, the thermoplastic welding or lamination of the inner UD tape can be performed in a rapid and simple continuous process along the continuous production of the honeycomb core. This results in an intermediate panel with a single-ply UD tape reinforced skin.

[0051] The width of the final sandwich panel can be achieved by a 90° rotation of the machine direction of the processed intermediate panel. The final width can be obtained by cutting the honeycomb core to length with the UD reinforcement tape. These tapes are applied to obtain an intermediate panel with a single-ply UD reinforced skin. This reduces waste and is advantageous in terms of cost.

[0052] The final panel width is limited only by the width of the second laminator or thermoplastic welder. Thus, for example, inputting honeycomb core production with a width of only 400 mm to 1200 mm, panels with a width of 2 m to 3 m can be produced.

[0053] Since the heat flux required for the calibration and lamination of the first skin layer is small, a higher inline production speed of the honeycomb core is possible. Less heat has to pass through the thinner skin material (single-ply) to reach the core due to the core-skin bonding process by thermoplastic welding.

[0054] The flexible use of variable tape widths and the easy width change are possible by arranging several rolls of narrow UD tapes adjacent to each other in one or both of the first and second lamination steps. This brings cost advantages and facilitates the procurement of UD tapes. Furthermore, the dependence on the availability of wide cross-ply production lines is reduced.

[0055] The intermediate unwinding and rewinding steps of the UD tape during cross-ply production are not required. The handling of single-ply UD reinforced intermediate panels is much easier compared to the separate handling of pre-cut 90° UD tape sheets in the production of cross-ply skin laminates. Furthermore, the proposed process enables the improvement of the surface quality of the final panel due to the low lamination temperature of the second skin layer.

[0056] A potential drawback when joining core sheets to manufacture large-sized sandwich panels is that the interruption of the core can reduce the shear performance of the core and the skin support, and may significantly degrade the mechanical properties of the final large-sized sandwich panel. The present invention avoids this degradation of mechanical properties by at least one means, preferably two or more means, that provide reinforcement within or across the gaps between the honeycomb core panels in the joining area. This reinforcement can be achieved by connecting and / or overlapping the core layers and / or by interpenetrating the core edges. This can also be achieved, optionally, along the production of continuously produced honeycomb cores, by in-line edge trimming of both edges of the intermediate single-ply UD reinforced honeycomb core panels. This trimming and preparation of the edges results in a reinforcement including improved edges of the panel, enabling better alignment and joining of the panels with an overlap of the core sheets at the joints.

[0057] In the case of high-temperature thermoplastic resins, the welding of the thermoplastic composite skin layer has to be carried out at temperatures above 300 °C where a lower-cost PTFE belt laminator cannot be used. Sandwich panel production according to embodiments of the present invention allows the honeycomb core to be laminated or welded narrowly to an inner 0° UD tape (e.g., from a high-temperature thermoplastic resin such as PEI / CF or PEEK / CF) alongside high-temperature thermoplastic honeycomb production via a narrow steel belt laminator. Then, a low-melting-point thermoplastic adhesive is applied to a second outer layer of the 0° UD tape (after rotating the machine direction of the honeycomb core having the first inner UD layer by 90°) via a wide PTFE belt laminator.

[0058] For cost-effective sandwich panels composed of polypropylene (PP: polypropylene), it is of interest to laminate the UD tape on the outer layer in the second step at a lower temperature since the surface quality is improved at lower lamination temperatures. The decorative surface layer can be laminated at a lower temperature together with the second UD tape layer in the second lamination step, thereby maintaining a high-quality surface finish even if the decorative layer is made of the same polymer, which is desirable to enable recycling of the complete sandwich panel.

[0059] In the case of large-sized sandwich panels, e.g., for the sidewalls of a tractor trailer or a truck box, it is advantageous to locally and timely produce the final wide panel in a cost-effective process in order to reduce the transportation and storage costs of the sandwich panel.

[0060] The honeycomb core sheet according to an embodiment of the present invention has an array of polygonal cells such as hexagonal, rectangular or square cells, and the array has rows and columns. Each polygonal cell has lateral cell walls extending between the vertices of each polygonal cell, each polygonal cell is bounded on both sides by a coating layer plane, and the lateral cell walls of each polygonal cell are in the form of a polygonal ring. The first column 21 in FIG. 7a can be a cell closed at the top, and the second column 22 can be a cell open at the top. As shown in FIG. 7a, the first column 21 alternates with the second column 22. In FIG. 7a, one edge 23 of the core sheet can have cells open at the top, but at the right edge 24, the core sheet is trimmed so that the cells are closed at the top. The honeycomb core is longitudinally trimmed during the production of the continuously produced honeycomb core to produce an edge structure suitable for joining two or more panels to each other using edge joints made of the trimmed honeycomb core having the first and second edge connections 25 and 26.

[0061] FIG. 7a schematically shows such a trimmed honeycomb core sheet. At the edge 23, the cells are trimmed so that the cells are open at the top and the connection 25 is produced.

[0062] Typically, such a core sheet has in-plane dimensions that are much larger compared to the cell size. For example, the cell size can be 3 mm to 10 mm, while the width of the core sheet can be 400 mm to 1200 mm with a length of, for example, 2000 mm to 3000 mm.

[0063] Figures 7b and 7c show the joining of two honeycomb cores according to an embodiment of the present invention. Figure 7b shows two honeycomb core sheets having trimmed edges arranged side by side. In Figure 7c, the two honeycomb core sheets are shown overlapping such that the L-cell walls at the left edge of one core sheet are between the W-cell walls and within the honeycomb cells on the right side of the adjacent core sheet. This results in some interpenetration at the joining location, creating a region of higher core density, i.e., the overlapping region of two adjacent honeycomb sheets.

[0064] Figure 8 shows on the left a 3D image of a honeycomb core sheet having left and right edges trimmed according to the present invention.

[0065] Figure 9 shows two adjacent core sheets overlapping to form a region of greater core density.

[0066] Figure 10 shows a side view of two honeycomb cores having left and right edges of adjacent panels trimmed according to the present invention to provide an edge connection. This allows the two honeycomb cores to be pushed together to form an overlap. Each honeycomb core 32 is preferably formed from a plurality of polygonal cells arranged in an array, each polygonal cell having lateral cell walls (shown as vertical lines), each polygonal cell being bounded on both sides by a coating layer plane, and the lateral cell walls of each polygonal cell forming a polygonal ring. Such cores and their manufacture are shown, for example, in Figure 14.

[0067] Figure 11 shows a side view of two adjacent cores 32 as shown in Figure 1 (as 1, 2, 3), which are joined to each other by an overlap created by a trimming step to create a limited area of greater core density at the joint, thus providing some reinforcement.

[0068] Figure 12 shows a side view of two intermediate panels having 0° UD tapes 36, 37 on a honeycomb core 32. The UD tape layers 36, 37 are laminated on the honeycomb core 32, whereby the uppermost layer 36 on the left side and the lowermost layer 37 on the right side in Figure 12 are formed with a small offset equal to, for example, one of the cell wall widths a = c / √3 or half of the cell size c. This provides additional reinforcement at the joint between the two panels.

[0069] Figure 13 shows how those adjacent intermediate panels are arranged together. The outer UD tape layers 44, 45 are continuous across the connection of the intermediate panels. Below these layers are layers 36, 37. This provides additional reinforcement at the joint between the two panels.

[0070] Referring to Figure 14, an example of honeycomb core manufacturing such as a folded honeycomb core that can be used in any of the embodiments of the present invention will be described. The advantage of this honeycomb is that it can be manufactured continuously. Some of the cell ends are open. Figure 14 shows the use of a flat sheet or web made of a plastically deformable material. The plastically deformable material may be, for example, a thermoplastic polymer material or a fiber composite material, and the sheet may be a thermoplastic polymer and / or a thermoplastic elastomer polymer, or a polyolefin, particularly polyethylene or polypropylene, a polyester, particularly polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate or polyethylene-1,2-furandicarboxylate, a polyamide, particularly polyamide 6 or polyamide 6,6, a polycarbonate, a polyether ketone, a polyether ether ketone, a polyether ketone ketone polyether, a polyether ester, a polyphenylene sulfide, a polyether imide, a copolymer and a mixture thereof, and can be composed of a thermoplastic polymer selected from the group consisting of.

[0071] According to this embodiment, a flat web or sheet has plastic deformations 101, 102 formed mainly perpendicular to the material web. In regions 101 and 102, the material is deformed from the plane of the web, for example, into a polygon, for example, a trapezoid, or a sine curve, or an arc shape, etc. The deformations form ridges 108 and valleys 109, whereby each of them is not continuous. For example, a ridge is composed of a series of linear deformation portions 101, 102, for example, a polygon, for example, a trapezoid, or a sine curve, or a bow-shaped portion, etc. Preferably, the ridge has an upper surface that can be parallel to the plane of the material web initially (for example, as formed). When the 3D structure is rotated (also called "folded") to form a honeycomb cell, such two surfaces abut against each other.

[0072] The production direction is preferably as shown in FIG. 14, but a direction perpendicular thereto (parallel to axes 105 and 106) can equally be used.

[0073] Regions 101 and 102 are preferably formed by being inclined, i.e., rotated towards each other around axes 105 and / or 106, in order to additionally form U-shaped or V-shaped connection areas 103 and 104. The connection areas 103 and 104 separate the raised portions 101, 102 such as polygons, such as trapezoids, or sinusoidal curves, or arcuate portions, etc. within one column of the regions 101, 102. One connection area 103, 104 is arranged between two raised portions 101, 102, and the connection area 103 alternates with the connection area 104 along the columns of the regions 101, 102. The connection areas 103, 104 form intersecting valleys, i.e., are perpendicular to the valley 109. Adjacent intersecting valleys are on both sides of the web material. The rotation of the raised portions to move the raised portions 101, 102 to the initial position in FIG. 14 is preferably carried out simultaneously with the deformation being arranged on the web of the material. The web material is stretched at the transition between the raised portions 101 and 102 to form connection areas 103 and 104 that are substantially perpendicular to the outer surfaces of the raised portions 101 and 102. The angle between the connection areas 103 and 104 on different raised portions allows a part of the tool to enter and thus allows these portions to be formed. In the direction of its width, the web material can vary its dimensions in the directions of axes 105 and 106, but in the production direction, the length of the web material does not vary in dimensions.

[0074] The deformation of the web or sheet material in regions 101 and 102 serves the purpose of forming a three-dimensional shape that forms the walls of the cell halves of the folded final product. The cells thus formed are structural and load-bearing elements of the folded honeycomb core, and their walls extend transversely to the longitudinal direction of the folded final product. The cells formed by folding preferably have a cylindrical cross-section, and the axis of the cylinder extends transversely to the longitudinal direction of the folded final product and the thickness direction of the ultimately produced flat honeycomb core. The basic cross-sectional shape of the cell can be selected as desired, for example circular or polygonal, especially an even polygon, such as a hexagon. The final cell shape is determined by the shape of the deformation ridges 101, 102 in the original web and how they are folded. As schematically shown on the right side of FIG. 14 when the web is fully folded, each cell is formed from two half-cells. The cells are arranged in rows. Each final cell is formed by the bottom and sides of two valleys 109 adjacent in the longitudinal direction (within the sheet or web material). The half-cells are preferably joined together across the contact surfaces from two ridges 108 adjacent in the longitudinal direction (within the web material). Thus, a folded honeycomb formed from a plurality of cells arranged in rows having the following characteristics is provided. The cells are adjacent to each other in the form of rings and have transverse cell walls bounded by the coating layer plane towards the two open sides of the cell, whereby each cell is completely cross-linked or closed on one or the other of the coating layer planes. The folded honeycomb can be formed from a flat web that is substantially uncut, i.e., a continuous sheet that is not porous. The sheet can be extruded. The plastic deformation of the sheet forms a 3D structure. Thus, the folded honeycomb includes a plurality of 3D structures, such as polygonal, sinusoidal or arcuate regions (101 and 102) formed by plastic deformation and connection areas (103 and 104) within the coating layer plane generated by plastic deformation. At least a part of the adjacent cell walls are preferably permanently connected to each other completely or partially, for example by gluing or an adhesive or welding.After the above manufacturing process, the honeycomb core 32 is conveyed by a conveyor such as a belt conveyor or a caterpillar (not shown) towards the laminator 38, particularly the calibrator and laminator 39. Refer to FIGS. 5 and 6. The 0° UD tape 36 is unwound from a roll and applied to the upper surface of the honeycomb core 32, optionally using temperature and / or pressure.

[0075] The present invention includes a final folded product that is a mixture of cells of different sizes or shapes. An important improvement of the honeycomb core for the performance of the sandwich panel is the support of the skin by the honeycomb core. A small area with a higher core density at the joint of the intermediate panel including the honeycomb core can ensure that the final large-sized sandwich panel does not have weak spots at the connections between the panels.

[0076] The edges of the panel can be cut at an angle, but with a standard trimming knife for the edges, it is easier to cut the panel straight and cut the core and the skin at the same width position. A small offset where there is no 0° UD tape layer on the honeycomb core is preferably generated by the offset in the lamination process. Alternatively, after the UD tape is laminated and the entire panel edge is trimmed, a small strip of the UD tape is removed.

[0077] The aim is to ensure that there is more skin material, particularly more core material, in order to better support the outer 0° UD tape layer and thus provide better mechanical properties in panel connections.

[0078] At the joint between the intermediate panels, the honeycomb core material overlaps, and in contrast to the overlapping of the UD tapes when the panels are pressed against each other, the UD tapes have little in-plane tensile strength in a direction perpendicular to the UD fiber orientation and 90° to the panel connection. However, it is also an option to push the UD tape layers together to create an overlap in order to avoid positioning the UD tapes for generating offsets and additional trimming of the UD tapes.

[0079] One edge of the honeycomb core sheet is cut at the end of the L-cell wall, and the other edge of the honeycomb core sheet is cut at the start of the L-cell wall.

[0080] At the position where the edges of the two honeycomb core sheets penetrate each other, for example, at a few millimeters, the density of the honeycomb core is, for example, twice as high as at any position within the honeycomb core. The penetration amount can be, for example, up to one cell wall length without cell distortion (a = cell size / √3), which results in a substantial improvement in core compression resistance and core shear resistance, and thus an increase in the local bending strength of the panel. In addition to the production advantages of the present invention, having the joint of the first 0° UD layer at the position where the honeycomb core sheets penetrate each other leads to a substantial improvement in the support of the outer 90° UD layer at this important position.

[0081] Further features of the present invention are disclosed in the following aspects of the present invention, each of which is an embodiment of the present invention.

[0082] A first aspect of a method for continuously producing a laminated reinforced honeycomb sandwich panel from a plurality of honeycomb cores as input materials, each of the honeycomb cores having two opposing major surfaces, one on each side of each of the honeycomb cores, and further aspects of the method are To form a layered honeycomb core, applying and laminating a first skin layer having a first 0° fiber reinforcement layer by thermoplastic welding, wherein one first skin layer is laminated on each major surface of each of the honeycomb cores, and the first 0° fiber reinforcement layer has fibers extending in a first machine direction; applying and laminating. Cutting the layered honeycomb core to form first and second intermediate panels having continuous straight edges. Trimming the opposing edges of the first and second intermediate panels to expose the edge connections. Rotating the first machine direction by 90° without rotating the intermediate panels, thereby obtaining a second machine direction; rotating. Joining the first intermediate panel to the second intermediate panel in continuous production to form a joint of the first and second intermediate panels having reinforcement at the joint of the first and second intermediate panels, the reinforcement being Overlapping or interpenetrating the edges of adjacent intermediate panels, or using an adhesive layer or adhesive loop for butt-jointing the first intermediate panel to the second intermediate panel, and optionally applying an in-line compressive force to the edge connections of the first and second intermediate panels, or one or more of completing the adhesive butt-joint; joining. Applying and laminating a second skin layer having a second 0° fiber reinforcement to the joined first and second intermediate panels by thermoplastic welding to form a laminated reinforced honeycomb core, wherein one second skin layer is laminated on each major surface of the first and second intermediate panels, and the fiber direction of the second skin layer is 90° with respect to the fiber direction of the first skin layer on each laminated reinforced honeycomb core; applying and laminating, including a first aspect.

[0083] 16. A further aspect of the method according to aspect 1, wherein trimming the opposing edges to expose the edge connections is performed before the cutting step, after the cutting step, or simultaneously with the cutting step.

[0084] 3. The honeycomb core has an array of polygonal cells, the polygonal cells have cell walls with cell wall lengths between the vertices of the polygon, and the interpenetration of the edge connections of the first and second intermediate panels is at most one cell wall length, a further aspect of the method according to aspect 1 or 2.

[0085] 4. A further aspect of the method according to any of the preceding aspects, further comprising joining a first 0° fiber reinforcement layer at the location where adjacent intermediate panels interpenetrate.

[0086] 5. For half of the polygonal cells along one edge, the upper or lower part of the cell is open, and along the opposite edge, for the other half of the cell, the upper or lower part is closed, a further aspect of the method according to aspect 3 or 4.

[0087] 6. At the edge of the reinforced honeycomb core, a trimming operation is performed such that cells from one reinforced honeycomb core have an open upper part, are cut in half, and are joined to cells from an adjacent reinforced honeycomb core, and the cells have a closed upper part that is cut in half, a further aspect of the method according to aspect 5.

[0088] 7. A further aspect of the method according to any of the preceding aspects, wherein the honeycomb core is a folded honeycomb core.

[0089] 8. The honeycomb core is made from a sheet composed of a thermoplastic polymer selected from the group consisting of thermoplastic polymers and / or thermoplastic elastomer polymers, or polyolefins, in particular polyethylene or polypropylene, polyesters, in particular polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate or polyethylene-1,2-furandicarboxylate, polyamides, in particular polyamide 6 or polyamide 6,6, polycarbonates, polyether ketones, polyether ether ketones, polyether ketone ketone polyethers, polyether esters, polyphenylene sulfides, polyetherimides, copolymers and mixtures thereof, a further aspect of the method according to any of the preceding aspects.

[0090] 9. A further aspect of the method according to aspect 8, wherein a sheet of a thermoplastic polymer or a sheet of a thermoplastic elastomer polymer is joined or laminated to each honeycomb core by thermoplastic welding.

[0091] 10. A further aspect of the method according to any of the preceding aspects, wherein a further reinforcing material is applied to the joints between the honeycomb cores.

[0092] 11. A further aspect of the method according to aspect 10, wherein the further reinforcing material is provided by a thermoplastic film or a thermoplastic adhesive film to which an excess loop is applied between adjacent edges of the laminated honeycomb cores.

[0093] 12. A further aspect of the method according to aspect 10 or 11, wherein the further reinforcing material is means for ensuring the transmission of shear forces in the honeycomb core.

[0094] 13. A further aspect of the method according to any of aspects 10 to 12, wherein the further reinforcing material is a thermoplastic film or a thermosetting adhesive film or a thermoplastic-coated aluminum layer that enables induction heating of the aluminum layer.

[0095] 14. A further aspect of the method according to any of aspects 11 to 13, wherein the further reinforcing material optionally sags between the honeycomb cores before the adhesion process is completed by pressure and heat.

[0096] Aspect 15. A plurality of honeycomb core sheets having edges and a first core density, and a first skin layer having a 0° fiber reinforcing material laminated on both sides of each of the plurality of honeycomb core sheets to form a laminated reinforced honeycomb core sheet. At the connection between the laminated reinforced honeycomb core and the first skin layer having 0° fiber reinforcement layers above and below the position where the edges of the honeycomb core are joined, in order to create an area with a second core density higher than the first core density, at the parallel locations of the edges of the laminated reinforced honeycomb core sheets where the edges overlap each other, or penetrate each other, or are deformed, the butt joints between the edges of the respective laminated reinforced honeycomb core sheets, and A reinforced honeycomb sandwich panel comprising a second skin layer having 90° fiber reinforcement layers on both sides of the reinforced honeycomb core laminated above and below the 0° fiber reinforcement layer to form a laminated reinforced honeycomb sandwich panel.

[0097] 16. Further aspect of the panel according to aspect 15, wherein the honeycomb core sheet has an array of polygonal cells, the polygonal cells have cell walls with cell wall lengths between the vertices of the polygon, and the interpenetration of the edge connections of the first and second intermediate panels of the honeycomb core sheet is at most one cell wall length.

[0098] 17. Further aspect of the panel according to aspect 15 or 16, further comprising a joint with the first 0° fiber reinforcement layer at the location where the intermediate panels of adjacent honeycomb core sheets interpenetrate.

[0099] 18. Further aspect of the panel according to aspect 16 or 17, wherein for half of the polygonal cells along one edge, the upper or lower part of the cell is open, and along the opposite edge, for the other half of the cells, the upper or lower part is closed.

[0100] 19. Further aspect of the panel according to aspect 18, at the edge of the laminated reinforced honeycomb core sheet, the cells from one reinforced honeycomb core sheet have an open upper part, are cut in half, and are joined to the cells from an adjacent reinforced honeycomb core sheet, and the cells have a closed upper part that is cut in half.

[0101] 20. Further aspect of the panel according to any of aspects 15 - 19, wherein the honeycomb core is a folded honeycomb core.

[0102] 21. The honeycomb core is made from a sheet composed of a thermoplastic polymer selected from the group consisting of thermoplastic polymers and / or thermoplastic elastomer polymers, or polyolefins, in particular polyethylene or polypropylene, polyesters, in particular polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate or polyethylene-1,2-furandicarboxylate, polyamides, in particular polyamide 6 or polyamide 6,6, polycarbonates, polyether ketones, polyether ether ketones, polyether ketone ketone polyethers, polyether esters, polyphenylene sulfides, polyetherimides, copolymers and mixtures thereof, a further aspect of the panel according to any one of aspects 15 to 20.

[0103] 22. A sheet of thermoplastic polymer or a sheet of thermoplastic elastomer polymer is joined or laminated to each honeycomb core by thermoplastic welding, a further aspect of the panel according to aspect 21.

[0104] 23. A further reinforcing material is applied to the joints between the honeycomb cores, a further aspect of the panel according to any one of aspects 15 to 22.

[0105] 24. The further reinforcing material is provided by a thermoplastic film or a thermoplastic adhesive film having excessive loops between adjacent edges of the laminated honeycomb cores, a further aspect of the panel according to aspect 23.

[0106] 25. The further reinforcing material is a means for ensuring the transmission of shear forces in the honeycomb core, a further aspect of the panel according to aspect 23 or 24.

[0107] 26. The further reinforcing material is a thermoplastic film or a thermosetting adhesive film or a thermoplastic coated aluminum layer enabling induction heating of the aluminum layer, a further aspect of the panel according to any one of aspects 23 to 25.

[0108] 27. The additional reinforcing material is an additional aspect of the panel according to any one of aspects 24 to 26, which optionally, by pressure and heat, sags between the honeycomb cores before completing the bonding process.

[0109] Aspect 28. Equipment for continuously producing a laminated reinforced honeycomb sandwich panel from a plurality of honeycomb cores as input materials, each of the honeycomb cores having two opposing main faces, one on each side of each of the honeycomb cores, and further aspects of the equipment are a first conveyor for conveying the input material to a laminator in a first machine direction, a storage for storing a first skin layer having a first 0° fiber reinforcement layer, a laminator for laminating the first skin layer by thermoplastic welding to form a layered honeycomb core, with one first skin layer laminated on each main face of each of the honeycomb cores, and the first 0° fiber reinforcement layer having fibers extending in the first machine direction, a cutter for cutting the layered honeycomb core to form first and second intermediate panels having continuous straight edges, a trimmer for trimming the opposing edges of the first and second intermediate panels to expose the edge connections, a second conveyor having a second machine direction that is 90° to the first machine direction, for receiving the layered honeycomb core without rotating the layered honeycomb core, means for joining a first layered honeycomb core to a second layered honeycomb core in continuous production to form a joint of the first and second honeycomb cores having reinforcement at the joint of the first and second layered honeycomb cores, the reinforcement at the joint including one or more of overlapping or interpenetrating the edges of adjacent intermediate panels, or using an adhesive layer or adhesive loop for butt-joining the first intermediate panel to the second intermediate panel at the butt joint, and optionally applying an in-line compressive force to the edge connections of the first and second intermediate panels, or completing the adhesive butt joint, A second storage for storing a second skin layer having a second 0° fiber reinforcement layer with respect to a second machine direction, the application being made on each side of each of the honeycomb cores, the second storage, and A second laminator for laminating a second skin layer by thermoplastic welding to form a honeycomb core, wherein one second skin layer is laminated on each major surface of each of the honeycomb cores, and the second 0° fiber reinforcement layer has fibers extending in a second machine direction, the second laminator, and a facility.

[0110] 29. The trimmer is configured to trim opposing edges to expose the edge connection, the trimming being performed before the cutter, after the cutter, or simultaneously with the cutter, a further aspect of the facility according to aspect 28.

[0111] 30. The honeycomb core has an array of polygonal cells, the polygonal cells having cell walls with cell wall lengths between the vertices of the polygon, and the interpenetration of the edge connections of the first and second intermediate panels is at most one cell wall length, a further aspect of the facility according to aspect 28 or 29.

[0112] 31. The trimmer is configured to perform a trimming operation at the edge of the reinforced honeycomb core such that cells from the edge of one honeycomb core have an open top, are cut in half, and are joined to cells from an adjacent reinforced honeycomb core, the cells having a closed top that is cut in half, a further aspect of the facility according to aspects 28 - 30.

[0113] 32. A further aspect of the facility is configured to manufacture a folded honeycomb core, a further aspect of the facility according to any of aspects 28 - 31.

[0114] 33. A facility for the continuous production of laminated reinforced honeycomb sandwich panels, the facility being configured to perform any of the methods of aspects 1 - 14.

Claims

1. A plurality of honeycomb core sheets having edges and a first core density, A first skin layer having 0° fiber reinforcements laminated on both sides of each of the plurality of honeycomb core sheets to form a laminated reinforced honeycomb core sheet, At the connection between the laminated reinforced honeycomb core and the first skin layer having a 0° fiber reinforcement layer above and below the position where the edges of the honeycomb core join, in order to create an area of a second core density higher than the first core density, the edges overlap each other, or penetrate each other, or are deformed, at the parallel locations of the edges of the laminated reinforced honeycomb core sheets, butt joints between the edges of each of the laminated reinforced honeycomb core sheets, A reinforced honeycomb sandwich panel comprising a second skin layer having 90° fiber reinforcements on both sides of the laminated reinforced honeycomb core above the 0° fiber reinforcement layer to form a laminated reinforced honeycomb sandwich panel.

2. The honeycomb core sheet has an array of polygonal cells, the polygonal cells have cell walls with cell wall lengths between the vertices of the polygon, and the interpenetration at the edge connection of the honeycomb core sheet is at most one cell wall length, the panel according to claim 1.

3. The panel according to claim 1 or 2, further comprising a joint with the first 0° fiber reinforcement layer at the location where adjacent honeycomb core sheets interpenetrate.

4. For half of the polygonal cells along one edge, the upper or lower part of the cell is open, and along the opposite edge, for the other half of the cell, the upper or lower part is closed, or, At the edge of the laminated reinforced honeycomb core sheet, the cells from one reinforced honeycomb core sheet have an open upper part, are cut in half, and are joined to cells from an adjacent reinforced honeycomb core sheet, and the cells have a closed upper part that is cut in half, the panel according to claim 2 or 3.

5. The panel according to any of the preceding claims, wherein the honeycomb core is a folded honeycomb core.

6. The panel according to any of the preceding claims, wherein the honeycomb core is made from a sheet composed of a thermoplastic polymer and / or a thermoplastic elastomer polymer.

7. The honeycomb core is made of a sheet composed of a thermoplastic polymer selected from the group consisting of polyolefins, particularly polyethylene or polypropylene, polyesters, particularly polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate or polyethylene-1,2-furandicarboxylate, polyamides, particularly polyamide 6 or polyamide 6,6, polycarbonates, polyether ketones, polyether ether ketones, polyether ketone ketone polyethers, polyether esters, polyphenylene sulfides, polyether imides, copolymers and mixtures thereof, the panel according to any of the preceding claims.

8. The sheet of thermoplastic polymer or the sheet of thermoplastic elastomer polymer is joined or laminated to each honeycomb core by thermoplastic welding, the panel according to claim 6 or 7.

9. A further reinforcing material is applied to the joint between the honeycomb cores, the panel according to any of the preceding claims.

10. The further reinforcing material is provided by a thermoplastic film or a thermoplastic adhesive film having excess loops between adjacent edges of the honeycomb core, or The further reinforcing material is a means for ensuring the transmission of shear forces in the honeycomb core, or The further reinforcing material is a thermoplastic film or a thermosetting adhesive film or a thermoplastic coated aluminum layer enabling induction heating of the aluminum layer, or The further reinforcing material is optionally a thermoplastic film or a thermosetting adhesive film or a thermoplastic coated aluminum layer enabling induction heating of the aluminum layer, which sags between the honeycomb cores before the adhesive process is completed by pressure and heat, the panel according to claim 9.

11. Equipment for continuously producing a laminated reinforced honeycomb sandwich panel from a plurality of honeycomb cores as input materials, each of the honeycomb cores having two opposing main surfaces, one on each side of each of the honeycomb cores, the equipment comprising A first conveyor for conveying the input material to a laminator in a first machine direction, A storage for storing a first skin layer which is a first 0° fiber reinforced layer, A laminator for laminating the first skin layer by thermoplastic welding to form a layered honeycomb core, wherein one first skin layer is laminated on each main surface of each of the honeycomb cores, and the first 0° fiber reinforcement layer has fibers extending in a first machine direction; A cutter for cutting the layered honeycomb core to form first and second intermediate panels having continuous straight edges; A trimmer for trimming the opposing edges of the first and second intermediate panels to expose the edge connection portions; A second conveyor having a second machine direction of 90° with respect to the first machine direction and for receiving the layered honeycomb core without rotating the layered honeycomb core; Means for joining the first layered honeycomb core to the second layered honeycomb core in continuous production to form the joint of the first and second honeycomb cores having reinforcement at the joint of the first and second layered honeycomb cores, wherein the reinforcement at the joint includes one or more of overlapping or interpenetrating the edges of adjacent intermediate panels, or using an adhesive layer or adhesive loop for butt-joining the first intermediate panel to the second intermediate panel at the butt joint, and optionally applying an in-line compressive force to the edge connection portions of the first and second intermediate panels, or completing the adhesive butt joint; A second storage for storing a second skin layer having a second 0° fiber reinforcement layer with respect to the second machine direction, wherein the application is made on each side of each of the layered honeycomb cores; A second laminator for laminating the second skin layer by thermoplastic welding to form a layered honeycomb core, wherein one second skin layer is laminated on each main surface of each of the layered honeycomb cores, and the second 0° fiber reinforcement layer has fibers extending in the second machine direction; and the equipment comprises the second laminator.

12. The equipment according to claim 11, wherein the trimmer is configured to trim the opposing edges to expose the edge connection portions, and the trimming is performed before the cutter, after the cutter, or simultaneously with the cutter.

13. The honeycomb core has array-shaped polygonal cells, the polygonal cells have cell walls having a cell wall length between vertices of the polygon, and the interpenetration of the edge connections of the first and second intermediate panels is at most one cell wall length. The facility according to claim 11 or 12.

14. The trimmer is configured to perform a trimming operation at the edge of the reinforced honeycomb core such that the cells from the edge of one honeycomb core have an open top, are cut in half, and are joined to cells from an adjacent reinforced honeycomb core, and the cells have a closed top that is cut in half. The facility according to any one of claims 11 to 13.

15. The facility is configured to manufacture a folded honeycomb core. The facility according to any one of claims 11 to 14.

16. A facility for the continuous production of laminated reinforced honeycomb sandwich panels, the facility being configured to perform any of the methods of claims 17 to 27.

17. A method for continuously producing a laminated reinforced honeycomb sandwich panel from a plurality of honeycomb cores as input materials, each of the honeycomb cores having two opposing main surfaces, one on each side of each of the honeycomb cores, the method comprising: Applying and laminating a first skin layer having a first 0° fiber reinforcement layer by thermoplastic welding to form a laminated honeycomb core, with one first skin layer laminated on each main surface of each of the honeycomb cores, the first 0° fiber reinforcement layer having fibers extending in a first machine direction; Applying and laminating; Cutting the laminated honeycomb core to form first and second intermediate panels having continuous straight edges; Trimming the opposing edges of the first and second intermediate panels to expose the edge connections; Rotating the first machine direction by 90° without rotating the intermediate panels, thereby obtaining a second machine direction; Rotating; Joining the first intermediate panel to the second intermediate panel in continuous production to form the joint of the first and second intermediate panels having reinforcement at the joint of the first and second intermediate panels, the reinforcement being: Overlapping or interpenetrating the edges of adjacent intermediate panels, or using an adhesive layer or adhesive loop to adhesively bond the first intermediate panel to the second intermediate panel at the butt joint, and optionally applying an in-line compressive force to the edge connection of the first and second intermediate panels, or one or more of completing the adhesive butt joint, including joining; Applying and laminating a second skin layer having a second 0° fiber reinforcement to the joined first and second intermediate panels by thermoplastic welding to form a laminated reinforced honeycomb core, wherein one second skin layer is laminated on each major surface of the first and second intermediate panels, and the fiber direction of the second skin layer is 90° with respect to the fiber direction of the first skin layer on each laminated reinforced honeycomb core, including applying and laminating;

18. The method according to claim 17, wherein trimming the opposing edges to expose the edge connection is performed before the cutting step, after the cutting step, or simultaneously with the cutting step.

19. The honeycomb core has an array of polygonal cells, the polygonal cells have cell walls with cell wall lengths between the vertices of the polygon, and the interpenetration of the edge connections of the first and second intermediate panels is at most one cell wall length. The method according to claim 17 or 18.

20. The method according to any one of claims 17 to 19, further including joining the first 0° fiber reinforcement layer at the location where adjacent intermediate panels interpenetrate.

21. For half of the polygonal cells along one edge, the upper or lower part of the cell is open, and along the opposing edge, for the other half of the cell, the upper or lower part is closed. The method according to claim 19 or 20.

22. At the edge of the reinforced honeycomb core, the cells from one reinforced honeycomb core have an open upper part, are cut in half, and a trimming operation is performed so that they are joined to the cells from an adjacent reinforced honeycomb core, and the cells have a closed upper part that is cut in half. The method according to claim 21.

23. The method according to any one of claims 17 to 22, wherein the honeycomb core is a folded honeycomb core.

24. The honeycomb core is made of a sheet composed of a thermoplastic polymer and / or a thermoplastic elastomer polymer, or a polyolefin, particularly polyethylene or polypropylene, a polyester, particularly polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate or polyethylene-1,2-furandicarboxylate, a polyamide, particularly polyamide 6 or polyamide 6,6, a polycarbonate, a polyether ketone, a polyether ether ketone, a polyether ketone ketone polyether, a polyether ester, a polyphenylene sulfide, a polyether imide, a copolymer and mixtures thereof, and is made from a sheet selected from the group consisting of thermoplastic polymers, according to the method of any one of claims 17 to 23.

25. The sheet of the thermoplastic polymer or the sheet of the thermoplastic elastomer polymer is joined or laminated to each honeycomb core by thermoplastic welding, according to the method of claim 24.

26. A further reinforcing material is applied to the joint between the honeycomb cores, according to the method of any one of claims 17 to 25.

27. The further reinforcing material is provided by a thermoplastic film or a thermoplastic adhesive film to which an excess loop is applied between adjacent edges of the laminated honeycomb cores, or The further reinforcing material is a means for ensuring the transmission of shear forces in the honeycomb core, or The further reinforcing material is a thermoplastic film or a thermosetting adhesive film or a thermoplastic coated aluminum layer that enables induction heating of the aluminum layer, or The further reinforcing material optionally sags between the honeycomb cores before the adhesive process is completed by pressure and heat, according to the method of claim 26.

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