Structure and molded part

Abstract

Component and / or layer composite, produced in particular by the vacuum infusion process, preferably from predominantly natural materials, in which wood-like layers as well as textile reinforcement and flow layers are arranged in a materially bonded, preferably alternating layer arrangement within a positively or negatively executed form and are impregnated and cured by means of an infusion process, in particular a vacuum infusion process, with a preferably biogenic matrix under a membrane with at least one inlet and one outlet, preferably under a flexible membrane, wherein in a work step preceding the infusion process the layers are brought together to form a layer stack and fixed immovably to each other.

Description

[0001] The invention relates to a plate-, disc-, rod-, beam-, or shell-shaped molded part and molded parts, manufactured by the infusion or vacuum infusion process, from glued layers of wood and textiles. The invention also relates to a hull, deck, or superstructure wall, as well as integrated structural elements of a watercraft, and the deck, bottom, nose, tail, and rails of a surfboard, manufactured using the method. The invention can also be used in aircraft or wind turbines for energy generation.

[0002] Vacuum infusion processes for the production of fiber-reinforced plastics have been known for a long time. Such fiber-reinforced plastics have at least two components: the fiber reinforcement, which gives the workpiece the desired properties, and the resin matrix, which surrounds and protects the fibers. In the vacuum infusion process, the fibers are placed dry into a mold, and the resin is drawn into the mold by applying a vacuum. The vacuum removes air bubbles from the laminate and cures the laminate under pressure.

[0003] A molded part that utilizes vacuum gluing is also known from wooden boatbuilding. For example, DE 28 30 938 discloses a method for manufacturing hulls, decks, and superstructures from wood for sailing, rowing, or motorboats, in which several thin layers of wood (veneers) are first coated with an adhesive on at least one surface and then layered on top of each other. These sandwiches are then formed into a boat-sized shape and then vacuum-glued to create a dimensionally stable bond. The vacuum gluing process works by surrounding the sandwich with a membrane, which is preferably flexible, from which the air is then evacuated. Due to the vacuum, the ambient pressure presses the layers of the sandwich evenly against each other, allowing the adhesive to cure under pressure.

[0004] However, this method did not become established in wooden boatbuilding due to the great effort involved.

[0005] The object of the present invention is now to make the molded part or structure economically and ecologically attractive, particularly for wooden boat building, with the environmentally friendly and sustainable aspect of the invention being significant.

[0006] This problem is solved by the molded part or structure according to claim 1. Specific embodiments are described in the dependent claims.

[0007] The special feature of the molded part according to the invention lies in the fact that a stable sandwich of several veneer layers, or several bonded veneer layers, particularly of plywood, is first constructed on a template. This sandwich corresponds to the final molded part. A veneer layer can be formed as a single layer of several adjacent thin sheets or as larger, adjacent layers developed from the three-dimensional final shape of the (molded) component into a plane. These layers are made of wood whose joints are at least partially permeable to flowable resin from layer to layer. In a particularly simple embodiment, the individual veneer layers are held together by staples. Due to the rough structure of the wood surfaces, the overlapping veneer layers form very narrow interlayers that allow the resin to flow across the surface.This sandwich is then sealed with a membrane before the flowable resin is introduced into the membrane and thus into the sandwich via vacuum infusion. The resin, which cannot pass through the individual wood sheets, is distributed homogeneously across the interlayers and joints of the entire sandwich.

[0008] The claimed method involves first attaching a textile or wood-like layer, which will later form an inner or outer surface, to a positive or negative mold or flat surface in a detachable manner. Further textile or wood-like layers are then alternately placed on top of this first layer and fixed against each other in a way that prevents movement. It is important that, within the resulting stack, the wood-like layers are always separated from each other by at least one textile layer.

[0009] The stack of layers is then sealed by a preferably reusable and flexible membrane, whereby the membrane does not need to enclose the entire shape, but only the stack of layers.

[0010] The space between the layer stack and the membrane, which can be evacuated from ambient air, must be equipped with at least one outlet leading to a vacuum pump and at least one inlet leading to a reservoir containing a flowable matrix (resin). It is important to be able to precisely control the matrix flow, or the moving front of matrix material, during the actual infusion of the layer stack. This can be advantageously achieved by systematically switching the inlet and outlet on and off, as well as reversing them.

[0011] The inlets are advantageously located at the bottom of the mold and the outlet at the top to ensure the resin spreads from bottom to top. Depending on the size of the molded part, it may also be advantageous to provide multiple outlets with extraction points.

[0012] In an infusion step, the flowable matrix material is pumped from the reservoir to an outlet via the vacuum pump or with the help of an additional pump that applies a different pressure to the reservoir of the matrix material than to the area enclosed by the membrane, penetrating and simultaneously wetting - especially also saturating the textile layers through the layer stack.

[0013] To ensure complete saturation of the layer stack with matrix material, the required amount of matrix material (with a reserve) is determined beforehand and compared with the amount arriving at the outlets. Saturation can be determined by comparing the flow rate of the incoming resin with the outgoing flow rate.

[0014] Products known from plastic boat construction can be used as matrix materials; preferably these are bio-based or have a high bio-based content. After the matrix material has cured, the sandwich (molded) component formed from the layer stack can be removed from the forming substrate.

[0015] Once saturated, the vacuum can be maintained to sustain pressure until the resin has cured; simply closing the inlet and outlet and switching off the pump may suffice.

[0016] The particular advantage of the molded part according to the invention lies in the fact that the fibers of wood-like materials, especially bamboo and native hardwoods and softwoods, can be combined with native textiles consisting of natural fibers, especially flax, hemp, jute, sisal, and nettle. This makes the (molded) components particularly sustainable due to the high natural fiber volume content.

[0017] Another important aspect is that particularly lightweight (molded) components can be manufactured, which is a great advantage especially in watercraft construction or also in aviation and / or in the production of wind turbine blades.

[0018] To achieve or even enable better flow between the wood-like layers, which are impermeable to the matrix material, it is advantageous if the wood-like layers comprise several adjacent wood-like layers with parallel longitudinal and transverse edges and, in particular, longitudinally oriented grain, joined by narrow gaps. These gaps allow controlled resin transfer between adjacent intermediate layers during the infusion step. It is important that the veneer sheets have a thickness between 1 mm and 3 mm, particularly 2 mm, and a width between 10 cm and 20 cm, particularly 15 cm. If these gaps are insufficient for matrix flow between the layers, especially if the width is greater than 20 cm, it is advantageous to further divide the wood-like layers, depending on their position within the layer (layer 1, 2, 3, etc.) and / or their position within the layer (e.g.,The strips should be provided with regularly and / or irregularly arranged perforations (holes) at the beginning, middle, and end (in the longitudinal direction). It is advantageous if the perforations have a diameter between 1 mm and 10 mm, preferably 3 mm or 6 mm. Holes are particularly necessary when the wood strips are not arranged in a crossed pattern. The advantage of the holes is most significant for large, wood-like layers.

[0019] To improve and homogenize the flow properties in the textile interlayers, it is important to add textile strips of the same or similar material to the textile layers by doubling them one or more times. These strips accelerate the flow of the resin between the inlets and outlets during the infusion step and promote distribution across the surface. It is further advantageous if at least one orientation of the textile strip is aligned with the fiber direction of the veneer and, in particular, if it is equidistant, i.e., equidistant and / or spaced at the same intervals.

[0020] With regard to a homogeneous distribution of the resin, it has proven particularly advantageous to use strips between 5 mm and 30 cm wide.

[0021] It is also advantageous if the wood-like layers are stacked on top of each other with the grain direction intersecting, especially if the shape is complex. For less complex areas of the (molded) component, it can be beneficial to work with large wood-like layers developed from the 3D final contour. The immovable fixation of the stacked layers can be ensured by fasteners such as nails or staples, or by bonding points. These bonding points can be coated with a fast-curing adhesive. To improve homogeneous evacuation, homogenization, and resin flow, a layer can be placed between the membrane covering or...A flow aid, in particular in the form of the same natural textile layer as within the layer structure, is provided between the foil wrapping and the outermost wood-like layer, provided that this is separated by a thin layer that does not adhere to the later (molded) component (release fabric).

[0022] The present invention protects a hybrid layered material and components made therefrom, in particular shell-shaped surface structures, in which high-quality components are produced from predominantly biogenic materials by means of an infusion process.

[0023] A key feature of the invention is that at least one layer of natural fibers in the composite layer simultaneously facilitates resin flow during infusion and permanently contributes to the mechanical strength of the component. This eliminates the need for separate flow aids, simplifies the manufacturing process, reduces working time, and produces a durable, clear-coatable component with high structural performance.

[0024] Hybrid layered material comprising at least one wood-like outer layer, at least one natural fiber layer and a polymer matrix, wherein the natural fiber layer both supports the resin flow during an infusion process and determines the mechanical properties of the layered composite.

[0025] The production of such a layered composite (according to material) can be achieved by arranging the aforementioned layers and impregnating them by means of vacuum infusion.

[0026] According to the invention, the natural fiber layer is not merely used as reinforcement, but is specifically used as a process-active layer to control the resin flow between outer layers, with this layer remaining a permanent part of the layer composite.

[0027] Material / hybrid layered material: • “Wood-like material”, especially native woods or bamboo • “Natural fiber layer” • “Polymermtarix” preferably thermosetting, especially epoxy resin, also bio-based resin systems • Dual function of the natural fiber layer • Resin flow / Infusion support • mechanical reinforcement • Natural fiber remains permanently in the component • Fiber volume content preferably ≥ 40 vol.% • Minimal polymer matrix consumption • Optional: Supporting core / sandwich material that remains permanently between the outer layers after impregnation of the natural fiber layers. Technology (infusion procedure) • Infusion preferably under negative pressure • Infusion in a closed or semi-closed device • No separate flow aids to support the infusion procedure • Use of the natural fiber layer for resin distribution • Production in one or a few process steps • large-format, curved bowls • Optional: reusable elastic membrane for creating the vacuum Component (shell or flat lightweight structures) Shell-shaped structures for watercraft (Boat hulls, decks, superstructures, surfboards)

[0028] Component, in particular shell-shaped structure, designed as a surface structure with integrated functional and reinforcement structures.

[0029] The shell-shaped structure according to the invention is designed as a shell-shaped surface support structure made of a hybrid layered composite, wherein the natural fiber layer is used both process- and structure-effectively and enables an integral construction with high functional integration. • “shell-shaped surface structure” • Boat hull / deck or watercraft in general • Hybrid layered composite as a load-bearing structure • Targeted fiber orientation (anisotropic) • integral construction (stringers, local reinforcements for force transmission, frames) See material, optionally with layer C rotor blade - aircraft or wind power

[0030] Component, in particular shell-shaped structure, designed as a surface structure with integrated functional and reinforcement structures.

[0031] The shell-shaped structure according to the invention is designed as a shell-shaped surface support structure made of a hybrid layered composite, wherein the natural fiber layer is used both process- and structure-effectively and enables an integral construction with high functional integration. • “shell-shaped surface structure” • Rotor blade in wind turbines or aircraft • Hybrid layered composite as a load-bearing structure • Targeted fiber orientation (anisotropic) • integral construction (local reinforcements for force transmission) See material, optionally with layer C machine cladding, especially for machine tools

[0032] Component, in particular shell-shaped structure, designed as a surface structure with integrated functional and reinforcement structures.

[0033] The shell-shaped or planar structure according to the invention is designed as a (shell-shaped) surface support structure made of a hybrid layered composite, wherein the natural fiber layer is used both process- and structure-effectively and enables an integral construction with high functional integration. • “shell-shaped surface structure” • Machine enclosure • Hybrid layered composite as a load-bearing structure • Targeted fiber orientation (anisotropic) • integral construction (local reinforcements for force transmission) • Optional: Metallic structure (grid, sheet metal strips) that remains permanently between the outer layers after impregnation of the natural fiber layers. See material, optional with layer C. Optional:

[0034] The structure or component is manufactured by wet lamination followed by vacuum pressing.

[0035] As with materials, except for C, also as a metallic raw material. A: e.g. bamboo, European woods, B: e.g. flax, hemp, jute, sisal C: metallic grids, sheets

[0036] Traditional yachts made of wood-like materials are considered sustainable because, with proper maintenance, they achieve a very long lifespan. Many of these yachts have been in service for more than 100 years, demonstrating the durability of this construction method. However, with the growing awareness of the poor recyclability of sandwich structures made from synthetic, energy-intensive fibers at the end of their product life cycle, the need arises to develop sustainable alternatives. Against this background, the present component and / or structure and / or composite layer according to the invention was created. Despite the longevity of classic construction methods and their sustainability advantages, affordable and simultaneously performance-oriented construction methods based on wood-like materials are currently lacking on the market.

[0037] Traditional craft techniques such as diagonal form gluing are cost-intensive, while modern composite construction methods offer high performance but rely predominantly on synthetic fibers and resins, thus entailing significant ecological disadvantages.

[0038] The targeted combination according to the invention with additional natural fiber layers for the simultaneous control of infusion and mechanical properties, as well as the integration of optional sandwich cores, is significant. Furthermore, sailboats made of natural composite materials do not exhibit end-of-life problems and also have an overall low energy requirement during production. Ideally, boats made of natural materials require energy only during production; during the operational phase, the propulsion energy comes predominantly from nature (wind, possibly supplemented by solar or water power). At the end of the product life cycle, they can either be thermally recycled—whereby the released energy is utilized and only the previously bound CO2 is released again—or mechanically shredded and used as granules in new products.

[0039] The task is to provide a molded part, component or layered composite that enables the economical production of hulls, provides an outer layer of wood-like materials in a clear-coatable form, enables complete impregnation and material bonding through vacuum infusion in a single process step, integrates critical areas such as the underside, keel area and force introduction zones integrally into the shell and creates an integral construction with high functional integration and a reduced number of components.

[0040] Furthermore, the environmental balance is to be improved through the use of sustainable resin systems, the avoidance of waste and a favorable overall energy balance over the entire life cycle. Further advantages of the invention • Directly paintable surface without marks from external flow aids. • Cost-effectiveness: Hulls can be efficiently manufactured using mold construction. • Integral design: critical areas and functional structures are integrated in the same step; fewer components, higher fatigue strength. • Sustainability: Use of renewable raw materials (wood-like materials, natural fibers, cork, balsa, agave). • Sustainable resin systems: Possibility of using bio-based epoxy resin (“green bio-epoxy”, “bio-epoxy”). • Waste reduction: Elimination of external flow aids and single-use materials. • Reusable vacuum technology: The use of silicone covers to generate the vacuum results in significantly less waste in mass production. • Lightweight construction: Sandwich construction with natural cores offers high lightweight construction potential. • Care & Durability: Outer layers can be varnished or oiled. • Process reliability: Natural fiber layers act as an infusion layer and ensure uniform impregnation. • Anisotropic layered composite: Combination of wood-like materials and natural fibers enables targeted

[0041] Adjustment of stiffness in different directions. • Multifunctional natural fiber layers: simultaneously serve as an infusion aid and as a mechanically effective reinforcement. • Optional sandwich structure for additional weight savings and stiffness. • Very low energy consumption throughout the entire product life cycle: energy input mainly in manufacturing, utilization predominantly through wind power from nature. • Optional thermal utilization with energy recovery and CO2 neutrality. • Optional material recycling as granules for secondary applications.

[0042] The invention will be described in more detail with reference to the following figures.

[0043] They show: Fig. 1: the basic structure of layer stacks (with n layers) in alternating layers Fig. 2: the layer structure with support material C Fig. 3: Structure of the molded part or layered composite (basic principle) Fig. 4: Extension of the layered structure to control matrix flow through multiple inlets and outlets Fig. 5: Reversal of at least one inlet and outlet using inlet or outlet B as an example Fig. 6: Enclosing the stack of layers with at least one textile intermediate layer Fig. 7: Stack of layers completely surrounded by a textile layer Fig. 8: Stacked layers consisting of at least 2 wood-like layers without a wood-like outer layer Fig. 9: Integral construction with wood-like outer layers Fig. 10: Integral construction with wood-like or textile outer layers Fig. 11: Integral construction in various combinations Fig. 12: Basic design of the layer structure Fig. 13: Extended layer structure with sandwich core

[0044] Fig. Figure 1 shows the basic structure of layer stacks (with n layers) in alternating layers. Layer A: structural top layer with low permeability, preferably wood or wood-like material Layer B: A textile surface structure, wettable with matrix material, exhibiting high gas and fluid permeability and simultaneously serving as a transport layer for the matrix material. → Matrix material preferably consisting of a bio-based epoxy resin polymer matrix derived from biogenic raw materials. Optional:

[0045] With layer C: Supporting core material that is bonded together by the natural fiber layers.

[0046] Layer properties: A, B and C: Preferably made from biogenic raw materials. A: easily wettable with adhesive matrix material B: easily impregnated with adhesive matrix material C: easily wettable and difficult or impossible to impregnate with adhesive matrix material Materials: A: e.g. bamboo, European woods, B: e.g. flax, hemp, jute, sisal C: e.g., agave, cork, balsa, Alternative C: metallic grids, sheets

[0047] Fig. Figure 4 shows an extension for controlling the matrix flow through multiple inlets and outlets. A: A puncture, breakthrough, or bore through an outer layer to reach the first textile intermediate layer, either at an inlet or outlet. These can occur repeatedly in the longitudinal and transverse directions of the outer layer at regular or irregular intervals. B: Multiple punctures, penetrations, or bores beneath an inlet or outlet through several superimposed wood-like layers. These can occur repeatedly in the longitudinal and transverse directions of the outer layer and in the intermediate layers at regular or irregular intervals; they need not be aligned with each other. The number of these punctures in the different layers can vary. C: At least two precisely aligned buttresses, penetrations, or bores through several superimposed wood-like and textile layers. The aim is to selectively access the textile intermediate layers. The superimposed bores in the wood-like layers can be connected by a tubular fitting (e.g., made of the same wood-like material) leading to an inlet or outlet.

[0048] Fig. 5 shows a reversal of at least one inlet and outlet using inlet or outlet B as an example. t=1 (t=2 to!) → Support of evacuation (suction of the resin front to increase throughput) t=2 (t=1 to!) → Introduction of matrix material (to increase throughput) Swapping of R and p- at one or more other times (relative to t=1 or t=2) to homogenize the matrix distribution. During curing, t=2 to!

[0049] Fig. 12 Basic design Layer structure Cover (1) Outer layer wood-like material (2) Natural fiber flow layer with polymer matrix (3) Inner layer wood-like material (4) Form (5)

[0050] Fig. 13 Extended layer structure with sandwich core cover (1) Outer layer wood-like material (2) Natural fiber flow layer with polymer matrix (3) Sandwich core material (4) Natural fiber flow layer with polymer matrix (5) Inner layer wood-like material (6) Form (7) QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 28 30 938

[0003]

Claims

[1] Component and / or layer composite, produced in particular by the vacuum infusion process, made preferably predominantly of natural materials, in which wood-like layers as well as textile reinforcement and flow layers are arranged in a materially bonded, preferably alternating layer arrangement within a positive or negative mold and are impregnated and cured by means of an infusion process, in particular a vacuum infusion process, with a preferably biogenic matrix under a membrane provided with at least one inlet and one outlet, preferably under a flexible membrane, wherein in a step preceding the infusion process the layers are brought together to form a layer stack and fixed immovably to one another. [2] Component and / or layer composite according to claim 1, characterized by, that fibers from wood-like materials, in particular bamboo and native hardwoods and softwoods, are used with a combination of native textiles consisting of natural fibers, in particular flax, hemp, jute, sisal, nettle, wherein the manufactured (molded) components are particularly sustainable due to the high natural fiber volume content, and / or that in a resulting stack the wood-like layers are always separated from each other by at least one textile layer, and / or that the layers are provided with bores suitable for impregnation and / or evacuation, which are designed to selectively reach entire or partial textile intermediate layers, thereby enabling the production of reproducible, serially manufactured components. [3] Component and / or layer composite according to claim 1 or 2, characterized by, that the stack of layers is sealed by a particularly reusable and flexible membrane, wherein the membrane does not enclose the entire shape, but only the stack of layers. [4] Component and / or layer composite according to any one of the preceding claims, characterized by , that the space created between the layer stack and the membrane, which can be evacuated from ambient air, is provided with at least one outlet leading to a vacuum pump, and that at least one inlet is provided leading to a reservoir with a flowable matrix (resin), wherein the matrix flow or the moving front of matrix material during the infusion of the layer stack can be controlled in a targeted manner, wherein the control is achieved by systematically switching on and off, as well as reversing inlets and outlets. [5] Component and / or layer composite according to any one of the preceding claims, characterized by, that at least one inlet is provided at the lower part of the mold and the outlet at the top of the mold to ensure that the resin spreads from bottom to top, wherein the at least one outlet is provided with a suction point. [6] Component and / or layer composite according to any one of the preceding claims, characterized by that biogenic materials are used as matrix material. [7] Component and / or layer composite according to any one of the preceding claims, characterized by , that particularly lightweight (molded) components can be manufactured, especially (molded) components for watercraft construction, in aviation and / or in the manufacture of wind turbine blades (wind power plants). [8] Component and / or layer composite according to any one of the preceding claims, characterized by, that to achieve better flow between the wood-like layers impermeable to the matrix material, or generally, the wood-like layers comprise several wood-like layers adjacent to one another by means of narrow joints, with parallel longitudinal and transverse edges and, in particular, longitudinally running fibers, wherein the joints allow the controlled transfer of resin between adjacent intermediate layers during the infusion step, wherein the veneer sheets have a thickness between 1 mm and 3 mm, in particular 2 mm, and a width between 10 cm and 20 cm, in particular 15 cm, and / or wherein, in particular, for widths of the veneer sheets greater than 20 cm, the wood-like layers are provided with regularly and / or irregularly arranged perforations (bores), wherein the perforations (bores) have a diameter between 1 mm and 10 mm, preferably in particular 3 mm or 6 mm. [9] Component and / or layer composite according to any one of the preceding claims, characterized by , that to improve and homogenize the flow properties in the textile intermediate layers, the textile layers are doubled once or several times with textile strips made of the same or similar material and / or that at least one orientation of the textile strip is aligned in the fiber direction of the veneer and in particular equidistant, i.e., equally far apart and / or having equal spacing, and / or that strips between 5 mm and 30 cm wide are used. [10] Component or molded component, in particular for aircraft and / or watercraft and / or wind turbines, further in particular machine fairing, fairing element, rotor blade, boat hull, according to any one of claims 1 to 9.

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