Process for producing a sandwich component

Abstract

The invention relates to a method for producing a sandwich component, comprising a preparation step, a mixing step, an application step, a placement step, and a curing step, in which the sandwich component blank is held at a predefined curing temperature for a predefined curing time, wherein the core layer starting material (9) expands and / or cures to form a core layer (7) to form the sandwich component (1). According to the invention, the core layer starting material (9) comprises essentially, preferably exclusively, biogenic starting material components.

Description

[0001] The invention relates to a method for producing a sandwich component according to the preamble of claim 1.

[0002] A generic method for producing a sandwich component comprises a preparation step, a mixing step, an application step, a laying step, and a curing step. In the preparation step, a first cover plate, starting material components for a core layer starting material, a core layer starting material, and a second cover plate are first prepared. Then, in the mixing step, the starting material components are mixed together to form the core layer starting material. Subsequently, in the application step, the core layer starting material—including a reinforcement material—is applied to the first cover plate and uniformed. In the subsequent application step, the second cover plate is placed and pressed onto the not yet cured core layer starting material to form a sandwich component blank.Subsequently, during the curing step, the sandwich component blank is held at a predefined curing temperature for a predefined curing time so that the core layer starting material expands and cures into a core layer, forming the sandwich component.

[0003] Previous processes have the disadvantage that the core layer starting material contains predominantly material components based on fossil raw materials, which means that an environmentally friendly implementation of the process is only possible to a limited extent.

[0004] DE 44 31 755 A1 discloses a sandwich panel made of starch foam. DE 198 23 507 A1 discloses a process for producing molded bodies based on carbon, carbides, and / or carbonitrides.

[0005] An object of the invention is to provide a method by means of which a sandwich component with as much biogenic material as possible can be produced in a simple, process-reliable and environmentally friendly manner.

[0006] This object is achieved by the features of the independent claim. Preferred developments of the invention are disclosed in the subclaims.

[0007] According to the invention, a method for producing a sandwich component is proposed, comprising a preparation step in which a first cover plate, starting material components - including a reinforcement material - for a core layer starting material, and a second cover plate are provided; a mixing step in which the starting material components are mixed together to form the core layer starting material; an application step in which the core layer starting material is applied to the first cover plate and preferably uniformed; a laying step in which the second cover plate is placed and preferably pressed onto the preferably uncured core layer starting material to form a sandwich component blank; and a curing step in which the sandwich component blank is held at a predefined curing temperature for a predefined curing time.wherein the core layer starting material expands and / or hardens to form a core layer, forming the sandwich component. According to the invention, the core layer starting material comprises essentially, preferably exclusively, biogenic starting material components. Because the core layer starting material contains a high proportion of biogenic raw materials, the process can be carried out in an environmentally friendly manner. Furthermore, the sandwich component produced by the process also contains a high proportion of biogenic raw materials, so that the sandwich component can be used in an environmentally friendly manner compared to known sandwich components.

[0008] For the purposes of the present invention, biogenic raw materials are understood to be raw materials that are not of fossil origin and are therefore not produced using petrochemicals. Biogenic raw materials include, on the one hand, renewable raw materials, i.e., raw materials of plant origin, as well as raw materials of animal origin that can be used for material or energy purposes outside of the food sector. Preferably, the biogenic raw material is a renewable raw material of plant origin.

[0009] In order to obtain a core layer starting material that is easy to process, an exemplary embodiment provides that the core layer starting material has citric acid and glycerol as starting material components and a biogenic raw material or filler, wherein it is particularly preferably provided that the biogenic raw material or

[0010] Filler is selected from the group of lignins, preferably lignin sulfonate, cellulose-based raw materials and / or cellulose-based plant fibers, starch-based raw materials, coffee grounds, chitin, protein-based raw materials and / or protein-based fibers or chitosan.

[0011] In order to advantageously obtain a core layer with improved chemical resistance, it is provided in a preferred embodiment that the core layer starting material has a resin system as a starting material component, wherein it is particularly preferably provided that the resin system has an epoxy resin and a hardener, preferably chemically matched to the epoxy resin.

[0012] In order to advantageously obtain a foamed and thus light and at the same time strong core layer, it is provided in an exemplary embodiment that the core layer starting material has a, preferably physical, blowing agent component as starting material component, wherein it is preferably provided that the blowing agent component has, preferably thermally, expandable microspheres, preferably of the type Expancel® 051 DU40 and / or of the type Expancel® 031DU40.

[0013] Chemicals and materials used: Epoxy resin (Dipon.de® Epoxyplast 100 PA), hardener (Dipon.de® Epoxyplast 100 PB), Citric acid (commercially available, drugstore DM) Propellant (NaHCO3, Omnilab, 13433-1 KG, item no.: 1279891 Expancel® 051 DU40 and Expancel® 031 DU40 from Nouryon Glycerol (Sigma Aldrich, G6279-1L, PCode: 102546367) Lignin sulfonate LIGNEX MG F from Sappi Biotech GmbH Castor oil from Carl Roth (CAS No. 8001-79-4, EC No. 232-293-8) Glass fiber mat (PD glass silk, powder-bonded glass fiber mat 3MA 111-200-160-S) Thermal conditioning of the coffee grounds:

[0014] In a preferred embodiment, the method according to the invention further comprises a preparation step, which comprises thermal conditioning of the coffee grounds at 60 to 80°C for 24 hours to 6 days or at 100°C to 120°C for 20 to 24 hours, preferably 22.5 hours to 24 hours.

[0015] In an additional or alternative embodiment, the thermal conditioning of the coffee grounds can include a drying step at temperatures greater than 100°C, preferably 110°C, for more than 24 hours. In the case of a drying step at temperatures greater than 100°C, preferably 110°C, for more than 24 hours, a further step involves the addition of 15 to 25% by weight of glycerin or castor oil. Alternatively, other polyhydric alcohols, fats, or oils can also be used as plasticizing additives. Usable lignins:

[0016] The following table provides an overview of the dependence of the properties of lignins on their production process (E. Fliedner et al., Lignin-based adhesives, Material use of lignin, 31, (2009), 63 - 79): Lignin properties Lignosulfonates Power soda Organosolv Soluble in Water Bases, organic solvents Bases Organic solvents Molmasse M n (g / mol) 15.000 - 50.000 1.000 - 3.000 800 - 3.000 500 - 5.000 Molar mass distributionM n / M w 6-8 2,5 - 3,5 2,5 - 3,5 1,5 - 2,5 Share of total pulp production 6% 85% 9% 0% Lignin volume (approx.) 3.000.000 t 42.500.000 t 4.5 .00 t - Utilization rate 33 % 0,25 % - -

[0017] In a preferred embodiment of the present invention, the lignin is a ligninsulfonate or a kraft lignin, preferably ligninsulfonate.

[0018] In order to advantageously achieve a high stability of the core layer starting material during the curing step, it is provided in an exemplary embodiment that the core layer starting material has a, preferably chemical, blowing agent component as a starting material component, wherein it is preferably provided that the blowing agent component is formed by a bicarbonate, preferably by sodium bicarbonate or by ammonium bicarbonate.

[0019] In order to be able to produce a sufficiently large amount of core layer starting material cost-effectively and with low dead weight, it is provided in an exemplary embodiment that the core layer starting material has a filler component as a starting material component, wherein it is preferably provided that the filler component preferably has lignin and / or thermally conditioned coffee grounds and / or wood flour and / or wood chips.

[0020] In order to simplify the process of mixing the starting material components in the mixing step, an exemplary embodiment provides that the mixing step is divided into a premixing step and a main mixing step, wherein it is particularly preferably provided that the premixing step is carried out before the main mixing step.

[0021] In an exemplary embodiment, it is provided that in the premixing step, the propellant component, preferably expandable microspheres, is first mixed with the filler component, preferably thermally conditioned coffee grounds, to form a premix, and that in the main mixing step, the premix is ​​mixed with the resin system.

[0022] In a specific embodiment, it is provided that in the main mixing step, a premix is ​​mixed with the filler component, preferably a first part of the lignin and / or the, preferably thermally conditioned, coffee grounds and / or the wood flour and / or the wood chips, as well as citric acid and / or glycerol to form the core layer starting material.

[0023] In an exemplary embodiment, it is provided that in the premixing step a second part of the lignin, preferably as a blowing agent component carrier, is mixed with the blowing agent component to form the premix.

[0024] Different compositions for the core layer starting material are listed below as examples. All described core layer starting materials can be used in the described process for producing the sandwich component.

[0025] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising wood chips, preferably wood chips of Albasia wood, and, preferably thermally expandable microspheres of the type Expancel® 051 DU40 from Nouryon, as a blowing agent component and an epoxy resin system comprising an epoxy resin and a hardener, wherein it is preferably provided that the starting material mixture contains 13 wt.% wood chips and 7 wt.%, preferably thermally expandable microspheres Expancel® 051 DU40 and 40 wt.% epoxy resin and 40 wt.% hardener.

[0026] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising wood chips, preferably wood chips of Albasia wood, and sodium bicarbonate as a blowing agent component and an epoxy resin system comprising an epoxy resin and a hardener, wherein it is preferably provided that the starting material mixture contains 12.62 wt.% wood chips and 9.71 wt.% sodium bicarbonate and 38.83 wt.% epoxy resin and 38.38 wt.% hardener.

[0027] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising citric acid and glycerol and lignin, preferably lignin sulfonate, wherein it is preferably provided that the starting material mixture contains 43.48% citric acid and 21.74% glycerol and 34.78% lignin, preferably lignin sulfonate.

[0028] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising citric acid and glycerol and lignin, preferably lignin sulfonate, and an epoxy resin and a hardener, wherein it is preferably provided that the starting material mixture contains 32.26% citric acid and 16.13% glycerol and 25.81% lignin, preferably lignin sulfonate, and 12.9% epoxy resin and 12.9% hardener, wherein it is preferably provided that the compositions are given by the following mixing ratios: Citric acid : Glycerol : Lignosulfonate : EP resin (A) : EP hardener (B) = 25 : 12.5 : 15 : 10 : 10 to 25 : 12.5 : 25 : 10 : 10. The ideal composition is: Citric acid : Glycerol : Lignin sulfonate: EP resin (A): EP hardener (B) = 25: 12.5: 20: 10: 10.

[0029] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising citric acid and glycerol and a first part of lignin, preferably lignin sulfonate, and a second part of lignin, preferably lignin sulfonate, as blowing agent component carrier and sodium bicarbonate as blowing agent component, wherein it is preferably provided that the compositions are given by the following mixing ratios: Citric acid : Glycerol : Lignosulfonate : Lignosulfonate (blowing agent carrier) : blowing agent (NaHCO3) = 25 : 12.5 : 15 : 10 : 0.6.

[0030] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising citric acid and glycerol and a first part of lignin, preferably lignin sulfonate, and a second part of lignin, preferably lignin sulfonate, as blowing agent component carrier and sodium bicarbonate as blowing agent component, wherein it is preferably provided that the compositions are given by the following mixing ratios: Citric acid : Glycerol : Lignosulfonate : Lignosulfonate (blowing agent carrier) : blowing agent (NaHCO3) = 25 : 12.5 : 15 : 10 : 1.2.

[0031] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising citric acid and glycerol and a first part of lignin, preferably lignin sulfonate, and a second part of lignin, preferably lignin sulfonate, as blowing agent component carrier and sodium bicarbonate as blowing agent component, wherein it is preferably provided that the compositions are given by the following mixing ratios: Citric acid : Glycerol : Lignosulfonate : Lignosulfonate (blowing agent carrier) : blowing agent (NaHCO3) = 25 : 12.5 : 20 : 10 : 5.

[0032] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising citric acid and glycerol and a first part of lignin, preferably ligninsulfonate, and a second part of lignin, preferably ligninsulfonate, as blowing agent component carrier and, preferably thermally expandable microspheres, preferably of the type Expancel® 031 DU40 from Nouryon, as blowing agent component, wherein it is preferably provided that the compositions are given by the following mixing ratios: citric acid : glycerol : ligninsulfonate : ligninsulfonate (blowing agent carrier) : blowing agent (Expancel® 031 DU40) = 25 : 12.5 : 20 : 10 : : 5.

[0033] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising citric acid and glycerol and a first part of lignin, preferably lignin sulfonate, and a second part of lignin, preferably lignin sulfonate, as blowing agent component carrier and, preferably thermally expandable microspheres, preferably of the type Expancel® 051 DU40 from Nouryon, as blowing agent component, wherein it is preferably provided that the compositions are given by the following mixing ratios: Citric acid : Glycerol : Lignosulfonate : Lignosulfonate (blowing agent carrier) : blowing agent (Expancel® 051DU40) = 25 : 12.5 : 20 : 5 : 2.5.

[0034] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising citric acid and glycerol and a first part of lignin, preferably lignin sulfonate, and a second part of lignin, preferably lignin sulfonate, as blowing agent component carrier and, preferably thermally expandable microspheres, preferably of the type Expancel® 051 DU40 from Nouryon, as blowing agent component, wherein it is preferably provided that the compositions are given by the following mixing ratios: Citric acid : Glycerol : Lignosulfonate : Lignosulfonate (blowing agent carrier) : blowing agent (Expancel® 051DU40) = 25 : 12.5 : 20 : 10 : 5.

[0035] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising citric acid and glycerol and a first part of lignin, preferably lignin sulfonate, and a second part of lignin, preferably lignin sulfonate, as blowing agent component carrier and, preferably thermally expandable microspheres, preferably of the type Expancel® 031DU40 from Nouryon, and of the type Expancel® 051 DU40 from Nouryon, as blowing agent component, wherein it is preferably provided that the compositions are given by the following mixing ratios: Citric acid : Glycerol : Lignosulfonate : Lignosulfonate (blowing agent carrier) : Blowing agent 1 (Expancel® 031DU40) : Blowing agent 2 (Expancel® 051DU40) = 25 : 12.5 : 20 : 10 : 1 : 2.

[0036] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising citric acid and glycerol and a first part of lignin, preferably lignin sulfonate, and an epoxy resin and a hardener and a second part of lignin, preferably lignin sulfonate, as a blowing agent component carrier and sodium bicarbonate as a blowing agent component, wherein it is preferably provided that the compositions are given by the following mixing ratios: Citric acid : Glycerol : Lignosulfonate : EP resin (A) : EP hardener (B) : Lignosulfonate (blowing agent carrier) : blowing agent (NaHCO3) = 25 : 12.5 : 20 : 10 : 10 : 10 : 5.

[0037] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising citric acid and glycerol and a first part of lignin, preferably ligninsulfonate, and an epoxy resin and a hardener and a second part of lignin, preferably ligninsulfonate, as blowing agent component carrier and, preferably thermally expandable microspheres of the type Expancel® 031DU40 from Nouryon, as blowing agent component, wherein it is preferably provided that the compositions are given by the following mixing ratios: citric acid : glycerol : ligninsulfonate : EP resin (A) : EP hardener (B) : ligninsulfonate (blowing agent carrier) : blowing agent (Expancel® 031DU40) = 25 : 12.5 : 20 : 10 : 10 : 3.5.

[0038] By way of example, it is provided that the core layer starting material is formed, preferably exclusively, by a starting material mixture comprising citric acid and glycerol and a first part of lignin, preferably ligninsulfonate, and an epoxy resin and a hardener and a second part of lignin, preferably ligninsulfonate, as blowing agent component carrier and, preferably thermally expandable microspheres, preferably of the type Expancel® 051 DU40 from Nouryon, as blowing agent component, wherein it is preferably provided that the compositions are given by the following mixing ratios: Citric acid : Glycerol : Lignosulfonate : EP resin (A) : EP hardener (B) : Lignosulfonate (blowing agent carrier) : Blowing agent (Expancel® 051DU40) = 25 : 12.5 : 20 : 10 : 10 : 3.5.

[0039] In order for the core layer starting material to be process-reliable, it is provided, for example, that the application step comprises a first application sub-step and an insertion sub-step for the reinforcement material and a second application sub-step, wherein it is provided that in the first application sub-step a first part of the core layer starting material is applied to the first cover plate, and that in the insertion sub-step a reinforcement structure is placed on the first part of the core layer starting material applied in the first application sub-step, and that in the second application sub-step a second part of the core layer starting material is applied to the reinforcement structure and / or to the first part of the core layer starting material.

[0040] In order to be able to carry out the method for producing the sandwich component in a simple, cost-effective and reproducible manner, it is preferably provided that in the provision step a forming tool with a preferably trough-shaped lower tool part and a lid-like upper tool part is provided, and that before the application step the first cover plate is placed in a tool recess delimited to the outside by the lower tool part, and / or that in the application step the core layer starting material is applied to the first cover plate lying in the tool recess, and / or that in the application step the second cover plate is placed in the tool recess and onto the preferably uncured core layer starting material, and / or that during the curing step the tool recess is closed with the upper tool part.Preferably, the tool recess can have a height 41 of 30 mm and a length 43 of 300 mm and a width 45 of 300 mm.

[0041] In order to be able to produce the sandwich component in a particularly resource-saving and energy-efficient manner, it is preferably provided that the predefined curing time has a curing value, wherein the curing value is in a range from 40 minutes to 60 minutes, preferably in a range from 45 minutes to 55 minutes, or wherein the curing value is 50 minutes, and / or it is preferably provided that the curing temperature has a curing temperature value, wherein the curing temperature value is in a range from 140 °C to 250 °C, preferably in a range from 180 °C to 200 °C, or wherein the curing temperature value is 190 °C.

[0042] In order to obtain a core layer starting material with few individual components and thus a resource-saving core layer starting material, it is provided, for example, that the core layer starting material comprises a filler component and a polymer component. In order to obtain a sandwich component that is as light as possible but mechanically resilient, it is preferably provided that the cover plate material of the first cover plate and / or the second cover plate is wood, preferably albasia wood or beech wood.

[0043] Preferably, it can be provided that the expandable microspheres expand during the curing step and / or that the chemical blowing agent decomposes during the curing step to form gases.

[0044] Embodiments of the invention are described below with reference to the accompanying figures.

[0045] They show: Fig.1 in a side view a lower tool part of a molding tool with a first cover plate; Fig. 2 in a side view the lower tool part with the first cover plate, to which a first part of a core layer starting material is applied; Fig. 3 in a side view the lower part of the tool with the first cover plate, wherein a reinforcement structure is placed on the first part of the core layer starting material; Fig. 4 shows a side view of the lower tool part with the first cover plate, wherein a second part of the core layer starting material is applied to the reinforcement structure; Fig. 5 in a side view the tool lower part with the first cover plate, wherein a second cover plate is placed on the second part of the core layer starting material; Fig.6 in a side view the lower tool part and a tool upper part of the forming tool, by means of which a tool recess of the lower tool part is closed, and Fig. 7 shows a side view of the molding tool with a sandwich component arranged in the tool cavity; Fig. 8 shows a side view of the manufactured sandwich component, and Fig. 9 in a perspective view a mold with a tool recess which has a height 41 of 30 mm and a length 43 of 300 mm and a width 45 of 300 mm.

[0046] Based on the Fig. 1 to 6, a method for producing a sandwich component 1 is explained. The sandwich component 1 has, as shown in the Fig.8, a first cover plate 3, specifically by way of example only an albasia wood cover plate with a thickness of 2.6 mm and , and a second cover plate 5, specifically by way of example only an albasia wood cover plate with a thickness of 2.6 mm and a width of 300 and a length of 300 mm, and a core layer 7 arranged between the first cover plate 3 and the second cover plate 5.

[0047] The method for producing the sandwich component 1 comprises several method steps, namely a preparation step, a mixing step, an application step which is divided into a first application sub-step and an insertion sub-step and a second application sub-step, a laying step and a curing step.

[0048] During the preparation step, a first cover plate 3 and starting material components for a core layer starting material 9 as well as a second cover plate 7 are provided. In addition, during the preparation step, a molding tool 21 is provided, which has a trough-shaped lower tool part 25 defining a tool recess 23 and an upper tool part 27. During the preparation step, the tool base of the lower tool part 25 defining the tool recess 23 at the bottom is lined with a PTFE film. The tool walls of the lower tool part 25 defining the tool recess 23 to the side are sprayed with a PTFE spray. Alternatively and preferably, the tool walls and the tool base, and particularly preferably also a part of the upper tool part 27 defining the tool recess 23 at the top, can be coated with PTFE.In the case of a PTFE-coated mold 21, the lining with PTFE film and / or spraying with PTFE spray can be omitted.

[0049] Subsequently, the first cover plate 3 is inserted into the tool recess 23 until the first cover plate 3 rests flat on the tool base of the tool lower part 25. This is shown in the Fig. 1. In addition, the part of the upper part of the tool 27 that borders the tool recess 23 is also covered with PTFE foil. The tool recess 23 has, as shown in the Fig. 9, has a height 41 of 30 mm and a length 43 of 300 mm and a width 45 of 300 mm, which gives the fillable volume.

[0050] Subsequently, in the mixing step, the starting material components are mixed together to form the core layer starting material 9. In the first application step, a first part of the core layer starting material 9 is then applied to the first cover plate 3 and made uniform. This is shown in Fig. 2. Subsequently, in the insertion step, a preferably textile reinforcement structure 31 is placed on the core layer starting material 9 applied in the first application step and not yet cured. This is shown in Fig.3. The reinforcement structure 31 is formed here merely by way of example by a glass fiber mat (PD glass silk, powder-bonded glass fiber mat 3MA111-200-160-S) with dimensions of 300 x 300 mm. Subsequently, in the second application step, a second part, i.e., the remaining residue, of the core layer starting material 9 is applied to the reinforcement structure 31 and preferably the first part of the core layer starting material 9 and uniformed. This is shown in Fig. 4. Subsequently, in the laying step, the second cover plate 5 is inserted into the tool recess 23 and placed onto the not yet cured core layer starting material 9. This is shown in Fig. 5. The tool recess is then closed with the tool upper part 27. This is shown in Fig. 6 shown.

[0051] Subsequently, the curing step is carried out, in which the molding tool 21, the first cover plate 3, the second cover plate 5 and the core layer starting material 9 are heated by means of a heating device (not shown), for example a circulating air oven, for a curing time in a range of, for example, 45 minutes to, for example, 60 minutes at a curing temperature of, for example, 190 °C. Depending on the specific composition of the core layer starting material 9, the core layer starting material 9 expands, as shown in the Fig.7, with the inclusion of gas bubbles 33 or expanded microspheres and hardens the core layer starting material 9 to form the core layer 7 and thus also to form the sandwich component 1. The reinforcement structure 31, if present, is part of the core layer 7 in all embodiments of the method and in all embodiments of the sandwich component 1. The mold 21 is then removed from the circulating air oven and quenched to hand temperature using tap water, and the sandwich component 1 is removed from the mold 21 after approximately 20 hours.

[0052] The core layer starting material 9 can comprise, merely by way of example, as starting material components, 372 g of ligninsulfonate and 104 g of thermally expandable microspheres of the type Expancel® 051 DU40 from Nouryon, as a blowing agent component, and 298 g of epoxy resin, specifically EpoxyPlast A from Dipon, and 298 g of hardener, specifically EpoxyPlast B from Dipon. These starting material components are mixed in the mixing step to form the core layer starting material 9, preferably with a weight of 1072 g. For the core layer starting material 9 with this composition, the curing temperature in the curing step is 190°C, and the curing time is 45 minutes. In the example described, the tool recess 23 of the molding tool 21 has a height 41 of 30 mm and a length 43 of 300 mm and a width 45 of 300 mm, which results in the fillable volume.

[0053] The core layer starting material 9 can comprise, merely by way of example, as starting material components, 387.4 g of thermally conditioned coffee grounds and 108.5 g of thermally expandable microspheres of the type Expancel® 051 DU40 from Nouryon, as a blowing agent component, and 310 g of epoxy resin, specifically EpoxyPlast A from Dipon, and 310 g of hardener, specifically EpoxyPlast B from Dipon. These starting material components are mixed in the mixing step to form the core layer starting material 9. For this purpose, the coffee grounds and the blowing agent component are first mixed together in the premixing step. Subsequently, the epoxy resin and the hardener are added, and the starting material components are mixed to form the core layer starting material 9, preferably with a weight of 1115.9 g. For the core layer starting material 9 with this composition, the curing temperature in the curing step is 190 °C and the curing time is 60 minutes.In the example described, the tool recess 23 of the molding tool 21 has a height 41 of 30 mm and a length 43 of 300 mm and a width 45 of 300 mm, which results in the fillable volume.

[0054] Of course, the core layer starting material 9 can also be used in all other described compositions in the described process. The compositions of the core layer starting material 9 mentioned in the two previous paragraphs are to be understood merely as examples. List of reference symbols 1 sandwich component 3 first cover plate 5 second cover plate 7 core layer 9 Core layer starting material 21 mold tool 23 Tool recess 25 Tool base 27 Upper tool part 31 Reinforcement structure 33 gas bubbles / pores / expanded microspheres 41 Height of the tool recess 43 Length of the tool recess 45 Width of the tool recess QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 44 31 755 A1

[0004] DE 198 23 507 A1

[0004] Cited non-patent literature

[0000] E. Fliedner et al., Lignin-based adhesives, Material use of lignin, 31, (2009), 63 - 79

[0016]

Claims

[1] Process for producing a sandwich component comprising: a provision step in which a first cover plate (3), starting material components for a core layer starting material (9) and a second cover plate (5) are provided, a mixing step in which the starting material components are mixed together to form the core layer starting material (9), an application step in which the core layer starting material (9) is applied to the first cover plate (3) and preferably made uniform, a laying step in which the second cover plate (5) is placed, and preferably pressed, onto the preferably uncured core layer starting material (9) to form a sandwich component blank, and a curing step in which the sandwich component blank is kept at a predefined curing temperature for a predefined curing time, wherein the core layer starting material (9) expands and / or cures to form a core layer (7) to form the sandwich component (1), characterized by that the core layer starting material (9) essentially, preferably exclusively, comprises biogenic starting material components. [2] Method according to claim 1, characterized by that the core layer starting material (9) has citric acid and glycerol as starting material components and a biogenic raw material, wherein it is particularly preferably provided that the biogenic raw material is selected from the group of lignins, preferably lignin sulfonate, cellulose-based raw materials and / or cellulose-based plant fibers, starch-based raw materials, thermally conditioned coffee grounds, chitin, protein-based raw materials and / or protein-based fibers or chitosan. [3] Method according to claim 1 or 2, characterized by that the core layer starting material (9) has a resin system as a starting material component, wherein it is particularly preferably provided that the resin system has an epoxy resin and a hardener, preferably chemically matched to the epoxy resin. [4] Method according to one of the preceding claims, characterized by that the core layer starting material (9) has a, preferably physical, blowing agent component as a starting material component, wherein it is preferably provided that the blowing agent component has, preferably thermally, expandable microspheres, preferably of the type Expancel® 051 DU40 and / or of the type Expancel® 031DU40. [5] Method according to one of the preceding claims, characterized bythat the core layer starting material (9) has a, preferably chemical, propellant component as a starting material component, wherein it is preferably provided that the propellant component is formed by a bicarbonate, preferably by sodium bicarbonate or by ammonium bicarbonate. [6] Method according to one of the preceding claims, characterized by that the core layer starting material (9) has a filler component as a starting material component, wherein it is preferably provided that the filler component preferably comprises lignin and / or thermally conditioned coffee grounds and / or wood flour and / or wood chips. [7] Method according to one of the preceding claims, characterized by that the mixing step is divided into a premixing step and a main mixing step, wherein it is particularly preferred that the premixing step is carried out before the main mixing step. [8] Method according to claim 7, characterized by that in the premixing step the blowing agent component, preferably expandable microspheres, is first mixed with the filler component, preferably thermally conditioned coffee grounds, to form a premix, and that in the main mixing step the premix is ​​mixed with the resin system. [9] Method according to claims 1, 2 and 6, characterized by that in the main mixing step, a premix is ​​mixed with the filler component, preferably a first part of the lignin and / or the, preferably thermally conditioned, coffee grounds and / or the wood flour and / or the wood chips, as well as citric acid and / or glycerol to form the core layer starting material. [10] Method according to claim 9, characterized by that in the premixing step a second part of the lignin, preferably as a blowing agent component carrier, is mixed with the blowing agent component to form the premix.

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