Method for producing a laminar composite, and laminar composite

Abstract

The invention relates to a method for producing a laminar composite (102) of a laminar-composite semi-finished product or of a laminar-composite structural component (100), wherein a layer arrangement (106) is provided comprising a reinforcement layer (110, 120), e.g. a fibre-reinforced reinforcement layer, and a polymer layer (130) arranged on a surface of the reinforcement layer, wherein the polymer layer (130) comprises a thermoplastic polymer material (131), the layer arrangement (106) is transformed into a laminar composite (102) by heating, in which laminar composite the polymer layer (130) has a deformable polymer layer (132), and the form of the laminar composite (102) is changed by applying force.

Description

[0001] Process for producing a layered composite and layered composite

[0002] The present invention relates to the technical field of the production of reinforced layered composites and structural components which are partially formed from polymers.

[0003] Layered composite structural components are installed, for example, in motor vehicles underneath traction batteries and are used in particular for intrusion protection, i.e. the protection of a traction battery from mechanical damage that can be caused by impacting objects while driving.

[0004] To produce layered composite structural components, fiber-reinforced reinforcement layers can first be pretreated in an oven. A sandwich composite can then be created using two reinforcement layers removed from the oven and cooled, with a polymer material sandwiched between them. This sandwich composite can then be converted into a sandwich structural component with the desired shape in a forming tool, subjected to heating and, if necessary, subsequent processing steps.

[0005] During forming, heat is applied via the outer surfaces of the reinforcement layers. This heats the polymer inserted between them to a target temperature suitable for forming. The reinforcement layers generally become hotter than the polymer core of the resulting layered composite. If a specific target temperature favorable for forming is to be set in the polymer core, the reinforcement layers must be exposed to a higher thermal load peak than the polymer core itself. In addition, the temperature in the core area rises more slowly, particularly in thick layered composites, so that the target temperature favorable for forming is not reached there or is reached only very slowly. Homogeneous heating of the core area with simultaneous low thermal load on the reinforcement layers on the outer surfaces can therefore only be achieved with a very slow heat application and thus a very slow and therefore inefficient process.

[0006] The described procedure is particularly time-consuming when complex, layered composite-based structural components of uneven thickness are to be manufactured. Uniform heating of the polymer core can then be achieved at the cost of considerable time and effort. This involves slow, uniform heating of the entire layered composite with uniform heat input in both thick and thin areas of the layered composite. This eventually results in approximately the same temperature being reached throughout the polymer core area. This time-consuming process can only be avoided with considerable technical effort, if the heating elements of a forming tool are designed with considerable technical effort to ensure a higher heat input in thick areas of the layered composite.

[0007] The present invention is based on the object of making a layered composite as well as semi-finished products and structural components based thereon accessible with the least possible time and technical effort.

[0008] The object is achieved according to the invention by the features of claim 1. There, a method for producing a layered composite, a layered composite semi-finished product or a layered composite structural component is specified, wherein a layer arrangement is provided, comprising a reinforcing layer, e.g. a fiber-reinforced reinforcing layer, and a polymer layer arranged on a surface of the reinforcing layer, wherein the polymer layer comprises a thermoplastic polymer material, the layer arrangement is converted into a layered composite by heating, in which the polymer layer comprises a deformable polymer layer, and the shape of the layered composite is changed by the application of force.

[0009] The term "layered composite" is used in connection with the invention as a general term. This general term also includes the layered composite semi-finished product and the layered composite structural component.

[0010] A layered composite semi-finished product is considered to be a product which is obtained after the application of force and which has a changed shape as a result of the application of force.

[0011] A layered composite structural component is considered, in particular, a component that can be obtained from a layered composite semi-finished product by post-processing. The post-processing may include, for example, the addition of connection points through which the layered composite structural component can be connected to other components, e.g., on or in the area beneath a traction battery of a motor vehicle. The connection points may, for example, include holes through which fastening elements, e.g., bolts, can extend.

[0012] The term "layer arrangement" refers here in particular to an arrangement of layers, i.e., the reinforcement layer and the polymer layer. The layers are typically not yet bonded to one another until heating. This is because bonding of the layers during heating is achieved, among other things, by the polymer layer comprising a deformable polymer layer as a result of the heating. Typically, the polymer layer melts completely or partially, and the molten polymer material adheres to the surface of the reinforcement layer. However, the term "layer arrangement" also includes arrangements in which the polymer layer already adheres to the reinforcement layer prior to heating. In general, heating then strengthens the adhesion of the polymer material of the polymer layer to the reinforcement layer.

[0013] Any layer that can be used to reinforce the polymer layer, that can withstand heating, and that can be deformed by applying force after heating can be considered as a reinforcement layer. The reinforcement layer can be a fiber-reinforced reinforcement layer.

[0014] The reinforcement layer, e.g., the fiber-reinforced reinforcement layer, may also comprise a polymer material. The polymer material comprised by the reinforcement layer may preferably be a thermoplastic or a resin.

[0015] The thermoplastic comprised by the reinforcement layer may preferably contain a polypropylene (PP), a polyamide (PA) or a polybutylene terephthalate (PBT) or combinations of at least two of these thermoplastics.

[0016] The resin comprised by the reinforcing layer may preferably contain a polyurethane resin, a polyamide resin or a combination of these resins.

[0017] The reinforcement layer can, for example, be a fiber-reinforced reinforcement layer, and the polymer material comprised by the reinforcement layer can be in contact with the surfaces of fibers of the reinforcement layer. The fibers can, for example, be embedded in the polymer material comprised by the reinforcement layer, impregnated with the polymer material, or arranged on a surface of the polymer material. The fibers of the fiber-reinforced reinforcement layer can run unidirectionally. The fiber-reinforced reinforcement layer can, for example, comprise a unidirectional fiber fabric.

[0018] The fibers of the fiber-reinforced reinforcement layer can be multidirectional. The fiber-reinforced reinforcement layer can comprise, for example, a multidirectional, particularly bidirectional, fiber fabric or a fiber woven fabric.

[0019] The fiber-reinforced reinforcement layer may comprise one or more, e.g. 1 to 10, fiber layers.

[0020] The fibers of the fiber-reinforced reinforcement layer may contain polymer fibers, e.g. aramid fibers, polyacrylonitrile fibers, partially oxidized polyacrylonitrile fibers; carbon fibers and / or mineral fibers, e.g. glass fibers.

[0021] At least some of the glass fibers may preferably be hollow gas fibers or glass fibers made of E-glass, R-glass or quartz glass.

[0022] The meanings of the terms E-glass and R-glass are known to the expert.

[0023] The polymer layer comprises a thermoplastic polymer material. The term "thermoplastic" can in particular mean that it melts completely or partially when heated and, after the shape of the layer composite has been changed by the application of force, solidifies again upon subsequent cooling. The thermoplastic polymer material comprised by the polymer layer can, for example, contain polyamide (PA), polyphthalamide (PPA), polypropylene (PP) or polyethylene (PE), whereby the following additives can optionally be provided: short and / or long fibers made of carbon and / or glass, mineral components, ceramic components, lubricants. The mass fraction of the additives is in particular at least approximately 40%, for example at least approximately 50%, and / or at most approximately 80%, for example at most approximately 70%. In particular, the mass fraction of the additives is approximately 60%.

[0024] The thermoplastic polymer material enclosed by the polymer layer can be foamable. The thermoplastic polymer material can be foamed chemically or physically. During chemical foaming, a substance, such as CO2, can be released through a chemical reaction. The resulting gas bubbles foam the thermoplastic polymer material.

[0025] During physical foaming, gas bubbles form from a volatile substance, e.g. N2, dispersed in the thermoplastic polymer material, which foam the thermoplastic polymer material.

[0026] According to the invention, the layer arrangement is converted by heating into a layered composite in which the polymer layer comprises a deformable polymer layer. Preferably, the layer arrangement is converted by heating into a layered composite in which the polymer layer is a deformable polymer layer. Those skilled in the art know that different thermoplastic polymer materials melt at different temperatures. The temperature to which the polymer layer is to be heated during heating is selected by the skilled person such that the formability of the resulting polymer layer is sufficient to achieve a desired shape of the layered composite, which is to be adjusted during the subsequent application of force.

[0027] According to the invention, the shape of the layered composite is changed by applying force. This can be done in a forming tool, e.g., by extrusion, compression molding, and / or thermoforming, preferably by extrusion and / or compression molding. In general, at least the shape of the polymer layer and preferably also the shape of at least one reinforcement layer are changed.

[0028] The forming tool can be designed with or without a tempering element. Preferably, the forming tool is designed with a tempering element. The tempering element allows the temperature of the forming tool surfaces that come into contact with the surfaces of the layered composite until the end of the force application to be adjusted.

[0029] The temperature control element can be a temperature control element through which a temperature control medium can be passed. It can be used, in particular, for heating. The method can preferably be used to produce a sandwich layer composite, a sandwich layer composite semi-finished product, or a sandwich layer composite structural component, wherein the provided layer arrangement is a sandwich layer arrangement in which the polymer layer is arranged between the reinforcement layer and another reinforcement layer.

[0030] The further reinforcement layer may preferably be of the type described herein for said reinforcement layer.

[0031] It may be preferable for the heating to take place in a joining tool and for the shape of the layered composite to be changed in a forming tool. Preferably, the joining tool and the forming tool are spatially separated.

[0032] This can have significant advantages. For example, the joining tool, which could be a furnace, and the forming tool can be operated at different temperatures. In particular, the joining tool can be operated at a higher temperature than the forming tool.

[0033] It is conceivable that only the heat which is transferred from the layer composite to the forming tool is supplied to the forming tool, e.g. after an initial heating of the forming tool.

[0034] When the layered composite is transferred from the joining tool to the forming tool, a surface of the layered composite that comes into contact with the surrounding air can approach the lower temperature at which the forming tool is operated.

[0035] It is preferred if the surface of the layered composite cools by YK, starting from the surface temperature that occurs during heating. Y is preferably at least 5%, in particular at least 10%, e.g. at least 15% of the temperature difference between the surface temperature of the layered composite that occurs during heating and the temperature of the ambient air. The temperature of the ambient air can be determined in the room in which the method according to the invention is carried out. A temperature gradient can occur in the layered composite when the layered composite is transferred from the joining tool to the shaping tool, the temperature inside the layered composite being higher than on a surface of the layered composite.

[0036] At the onset of the force application to change the shape of the laminate, the temperature inside the laminate, e.g., inside the polymer layer, may be higher (preferably at least 5 K, particularly preferably at least 15 K, e.g., at least 30 K higher) than at a surface of the laminate. This can result in the shape of the laminate being significantly changed by the force application, despite its relatively low surface temperature. Because of the increased temperature inside the laminate, the polymer layer is softer than would be expected given the surface temperature of the laminate.

[0037] It would be conceivable, for example, that at the beginning of the application of force to change the shape of the layer composite, a temperature inside the polymer layer is more than 220 °C and is thus higher than a temperature on a surface of the layer composite, which is, for example, less than 210 °C.

[0038] The person skilled in the art can adjust the temperatures inside and on the surface within the scope of the invention, taking into account the melting temperature of the polymer material used, so that shaping is possible and a stable layer composite is obtained.

[0039] This opens up the possibility of operating the forming tool at a relatively low temperature and changing the shape of the layered composite by applying force at a moment when the temperature inside the layered composite, in particular inside the polymer layer, is higher than the temperature at which the forming tool is operated.

[0040] The temperature at which the forming tool operates can be considered the average temperature of the forming tool surfaces that come into contact with the surfaces of the layered composite until the end of the force application. This temperature is also referred to herein as the average forming tool temperature. It can be adjusted on a forming tool with a temperature control element using the temperature control element.

[0041] The average forming tool temperature can be, for example, at least 20 °C, preferably 20 °C to 90 °C. The range from 20 °C to 90 °C is particularly advantageous because a forming tool can be temperature-controlled with water without pressure in this temperature range.

[0042] The joining tool temperature can advantageously be between 140 °C and 300 °C, preferably between 180 and 280 °C. Thus, by adjusting the dwell times in the joining tool accordingly, the optimal processing temperatures for many polymer materials (PP: 200 °C to 240 °C, PA: 260 °C to 280 °C) can be achieved.

[0043] An adaptation temperature difference AT, which is calculated by subtracting the average forming tool temperature from the joining tool temperature, can be at least 5 K, preferably at least 10 K, in particular at least 15 K, e.g. at least 40 K.

[0044] In the previously common operation of a forming tool, heat was introduced from a surface of the forming tool via a reinforcement layer into the polymer layer and then formed under the application of force. The forming tool was therefore also used to heat up an inserted layer arrangement. In order to achieve rapid heating, especially in the case of thicker layer arrangements, the forming tool was kept at a temperature above the desired forming temperature of the polymer layer or polymer layer. At the moment the force was applied, the temperature of the reinforcement layer was typically higher than the temperature in the polymer layer or polymer layer. The temperature gradient in the layer composite at the moment of forming was therefore the opposite of the temperature gradient that can be adjusted using the process control according to the invention.

[0045] According to the invention, preliminary heating in the joining tool, e.g., in an oven, can take place over a longer period of time, which can be from 1 to 120 minutes, preferably from 2 to 90 minutes. Finally, the layer arrangement does not occupy an expensive forming tool at this time. A thermal load peak in the reinforcement layer can be mitigated because the operating temperature of the joining tool can be set approximately to the target temperature at which the subsequent force is to be applied. This has the crucial advantage that relatively heat-sensitive reinforcement layers, which can comprise, for example, heat-sensitive polymer materials, can also be formed in combination with high-melting polymer layers.

[0046] A typical joining tool has one or more heating zones in which heating takes place.

[0047] The joining tool can be a furnace and the heating zone can be a furnace chamber.

[0048] The joining tool can be heated in stages. The joining tool can be a multi-stage convection oven or can include a multi-stage convection oven.

[0049] The joining tool may be a two-zone convection oven or may include a two-zone convection oven.

[0050] Different temperatures can prevail in different zones within the joining tool. In this case, the temperature in the zone reached last during the heating process within the joining tool is considered the joining tool temperature.

[0051] The connection tool can be accessible from one side or from two sides.

[0052] The joining tool can be a continuous joining tool accessible from two sides, through which the layer arrangement is guided and converted into the layer composite by heating.

[0053] The guidance can be achieved by a conveyor system.

[0054] It may be advantageous to transport the layer arrangement into the heating zone using a conveyor device and to transport the layer composite obtained after heating out of the heating zone using the conveyor device. The conveyor device can comprise, for example, a needle conveyor, a transport robot, and / or a needle gripper.

[0055] A typical forming tool has a forming zone in which the shape of the layer composite obtained from the joining tool is changed.

[0056] It may be advantageous if at least one conveyor device transports the layered composite from the joining tool to the forming tool. It may be particularly advantageous if the conveyor device takes the layered composite transported from the joining tool by the conveyor device and transports it into the forming tool.

[0057] The conveying device can have spacer elements. This can ensure that only the surface areas of the heated layered composite that are in contact with the conveying device come into physical contact with the conveying device. This can reduce the risk of uncontrolled adhesion of the heated layered composite to the conveying device. Uncontrolled adhesion of the heated layered composite to the conveying device would make it more difficult to introduce the layered composite into the shaping zone. The number of spacer elements is preferably at least 3. The spacer elements can, for example, be shaped such that they contact a maximum of 10%, e.g. a maximum of 3%, of a surface of the layered composite facing the conveying device, and the remaining areas keep this surface of the layered composite at a distance from the conveying device. The spacer elements can, for example, be needle-shaped.

[0058] The conveying device may comprise, for example, a conveyor arm or a conveyor belt. The conveying device, in particular the conveyor arm, may comprise a layered composite holding device, e.g., a needle gripper.

[0059] The layered composite holding device, e.g. the needle gripper, can have the spacer elements, which can be needle-shaped, for example.

[0060] The layered composite conveyed from the joining tool can be needled onto the conveyor device. This can mean, in particular, that the layered composite is gripped by means of at least one needle gripper. The shaping tool can also have spacer elements, e.g. at least three spacer elements. The layered composite can initially be placed on these spacer elements by the conveyor device. It can be advantageous if the spacer elements extend from a surface of a mold half of the shaping tool and are designed such that they are movable relative to the surface of the mold half. They can preferably be accommodated in the mold half. These spacer elements can, for example, be pin elements that are guided in guides. They are preferably guided in the guides such that the pin elements can be fully accommodated in the guides.

[0061] It can be advantageous if no active cooling of the layered composite occurs between the joining tool and the forming tool. This specifically means that cooling occurs solely through the ambient air. Of course, the ambient air can be recirculated and / or cooled.

[0062] A temperature adaptation time t, which elapses from the removal of the layered composite from the joining tool to its insertion into the forming tool, can be up to 150 seconds, preferably up to 50 seconds, further preferably up to 15 seconds, particularly preferably up to 10 seconds, e.g., up to 5 seconds. This can have the advantage that the temperature inside the layered composite remains sufficiently high for a subsequent change in the shape of the layered composite under the action of force. Shaping is then possible with the least possible expenditure of time and effort.

[0063] An adaptation temperature gradient G, which is calculated by dividing the adaptation temperature difference AT by the temperature adaptation time t, can be in a range of 0.005 to 50 K / s, preferably in a range of 0.01 to 45 K / s, particularly preferably in a range of 0.02 to 40 K / s, e.g. in a range of 0.05 to 35 K / s.

[0064] In view of the above, it may be advantageous if the heating conditions during heating and the temperature adaptation conditions are coordinated such that a temperature inside the deformable polymer layer exceeds a surface temperature of the layer composite when the layer composite is introduced into the shaping tool by at least 5 K, e.g. at least 20 K. The heating conditions during heating are understood to mean, for example, the duration and the temperature during heating. The temperature adaptation conditions are understood to mean, for example, the temperature of a medium extending around the layer composite, in particular air, and the temperature adaptation time in this medium from the removal of the layer composite from the joining tool until the introduction of the layer composite into the shaping tool.

[0065] In the process according to the invention, which allows operation of the forming tool at relatively low temperatures, the inherent tendency of the layered composite to adhere to a surface of the forming tool is lower than in other processes. Auxiliary materials that counteract adhesion in forming tools can therefore be completely or partially omitted. Production capacity can consequently be increased, because interruptions to production for introducing such auxiliary materials into the forming tool can be completely or partially eliminated.

[0066] According to the invention, the layer arrangement can be provided without prior heating of the reinforcing layer or layers.

[0067] While it was common practice to heat different layers separately to form a composite layer and then combine them to form the composite, the invention makes it possible to form the entire layer arrangement without heating the individual layers separately and to heat the layers together in the layer arrangement. Of course, this does not preclude the layer arrangement from being constructed from preheated layers.

[0068] During heating, the surface of the layer arrangement can reach a temperature of at least 5 K, in particular 6 K to 100 K, e.g., 10 K to 60 K, above the melting temperature of the polymer material contained in the polymer layer. This can enable very rapid heating, particularly with heat-resistant reinforcement layers, and thus further increase the efficiency of the process.

[0069] When reference is made herein to a melting temperature, this means the melting temperature determined by dynamic differential scanning (DSC) analysis according to EN ISO 11357-3:2018. At the onset of the application of force to change the shape of the layered composite, a temperature inside the layered composite can be at or above, preferably above, the melting temperature of the polymer material encompassed by the polymer layer, and a temperature at a surface of the layered composite can be at or below the melting temperature of the polymer material encompassed by the reinforcement layer. Preferably, the temperature at the transition from the polymer layer to the reinforcement layer is also at or above the melting temperature of the polymer material encompassed by the polymer layer.

[0070] This advantageously allows the shape of the layered composite to change easily under the action of force. At the same time, adhesion of a surface of the layered composite to the forming tool can be prevented.

[0071] According to the invention, the polymer material comprised by the reinforcing layer can, for example, correspond to the polymer material comprised by the polymer layer.

[0072] The preliminary heating and subsequent partial (e.g., passive) cooling during transfer to the forming tool can result in a temperature gradient. Consequently, the temperature at a surface of the layered composite can be lower than the temperature inside the layered composite.

[0073] This can advantageously enable the shape of the layered composite to be changed with little effort and largely prevent the layered composite from sticking to the forming tool.

[0074] The invention therefore makes it possible to obtain layered composite semi-finished products and layered composite structural components with a uniform polymer matrix, wherein the polymer matrix extends through several layers and comprises the same polymer material.

[0075] The melting temperature of a polymer material encompassed by the reinforcement layer may be lower than the melting temperature of a polymer material encompassed by the reinforcement layer. This applies in particular if a melt of the first polymer material encompassed by the reinforcement layer, which forms upon heating, adheres to fibers of the reinforcement layer and, in particular, does not drip off. Thus, the melting temperature Tsv of a polymer material encompassed by the reinforcement layer may be:

[0076] Ts > TSP - X where TSP is the melting temperature of the polymer material comprised by the polymer layer and X stands for 50 K, preferably for 20 K, e.g. for 10 K.

[0077] The polymer layer can be foamable.

[0078] The shaping step may comprise foaming at least one region of the polymer layer. The term "shaping step" refers to the change in the shape of the layered composite due to the application of force.

[0079] The foaming of the region can advantageously be promoted by a force which moves the two surface regions of the polymer layer adjacent to this region away from each other.

[0080] For example, the foaming of the region may occur within a molding tool comprising a first and a second mold half, and the external force may be applied by removing at least a portion of one mold half from at least a portion of the other mold half.

[0081] The object is also achieved according to the invention by a layer composite which is preferably obtainable by a process according to the invention, wherein the polymer layer can have a porous layer region.

[0082] The object is also achieved according to the invention by a layered composite semi-finished product which is preferably obtainable by a process according to the invention, wherein the polymer layer can have a porous layer region.

[0083] The object is also achieved according to the invention by a layered composite structural component, which is preferably obtainable by a process according to the invention, wherein the polymer layer can have a porous layer region. Preferably, the porous layer region can be spaced from the reinforcement layer and have a lower density than a region of the polymer layer lying between the porous layer region and the reinforcement layer. The density can be determined by cutting out defined polymer layer volumes from the porous layer region and from the region lying between the porous layer region and the reinforcement layer and weighing them. The determined mass is then divided by the respective polymer layer volume.

[0084] Of course, features described in connection with the method according to the invention can also form features of the layered composite according to the invention, the layered composite semi-finished product according to the invention or the layered composite structural component according to the invention.

[0085] Further preferred features and / or advantages of the invention are the subject of the following description and the drawings of exemplary embodiments.

[0086] The drawings show:

[0087] Fig. 1 is a schematic representation of a method according to the invention;

[0088] Fig. 2 is a schematic sectional view of a layer arrangement from Fig. 1;

[0089] Fig. 3 is a schematic representation of a connecting device from Fig. 1, which contains the layer arrangement shown in Fig. 2;

[0090] Fig. 4 is a schematic representation of a forming device containing a layered composite that can be formed therein; and

[0091] Fig. 5 is a schematic representation of a complex-shaped layered composite structural component.

[0092] Identical or functionally equivalent elements are provided with the same reference numerals throughout the figures. Fig. 1 schematically shows a method for producing a layered composite. A layer arrangement 106 is provided, which is shown in more detail in Fig. 2. It comprises two reinforcement layers 110 and 120. These are fiber-reinforced reinforcement layers. The layer arrangement 106 also comprises a polymer layer 130 between the two reinforcement layers 110 and 120. The polymer layer comprises a polymer material 131.

[0093] The reinforcement layers each also comprise a polymer material 133. The polymer material 133 is in contact with surfaces of fibers of the respective reinforcement layer.

[0094] On a support grid 184, the layer arrangement 106 is introduced into the joining device 180, also shown in Fig. 1. The joining device 180 can be a furnace. Therein, the layer arrangement 106 is converted into a layered composite 102 by heating. In the layered composite, the polymer layer 130 comprises a deformable polymer layer 132, which connects the reinforcement layers 110 and 120.

[0095] Subsequently, the layer composite 132 is introduced into a mold half 192 of a forming tool 190 by a conveying device 200 and the shape of the layer composite 132 is changed by the application of force, as indicated in Fig. 4.

[0096] Between the joining tool 180 and the forming tool 190, in particular while the layered composite 102 is in contact with the conveying device 200, there is no active cooling of the layered composite 102. Cooling occurs essentially only by dissipating heat into the air surrounding the layered composite.

[0097] The average forming tool temperature can be, for example, 85 °C. The joining tool temperature can be, for example, 181 °C. The adaptation temperature difference ΔT is then 96 K. The ambient air cools the surface of the layered composite, which is initially approximately 181 °C hot, quite quickly.

[0098] At 181 °C, the surface of the layer arrangement 106 reaches a temperature of slightly more than 10 K above the melting temperature of the polymer material 131 contained in the polymer layer 130 when heated. It can take, for example, 9 seconds from the removal of the layered composite 102 from the joining tool 180 to the introduction of the layered composite 102 into the forming tool 190. The temperature adaptation time t is therefore 9 seconds.

[0099] The adaptation temperature gradient is therefore 10.67 K / s.

[0100] When the force is applied to change the shape of the layered composite 102 in the forming tool, the temperature inside the polymer layer 132 can be significantly higher than at a surface of the layered composite 102. While the surface of the layered composite cools rapidly in the ambient air, the temperature inside the polymer layer 132, which was not directly exposed to the ambient air, remained significantly higher during the 9 seconds. The core temperature in the deformable polymer layer of approximately 181°C can exceed a surface temperature of the layered composite 102 when the layered composite 102 is introduced into the forming tool 190 by approximately 10 K.

[0101] Fig. 2 shows the layer arrangement 106 from Fig. 1 more clearly. It is a sandwich layer arrangement 107 in which the polymer layer 130 is arranged between the reinforcement layers 110 and 120. The process shown in Fig. 1 is therefore a process for producing a sandwich layer composite.

[0102] As shown in Fig. 3, heating in the joining tool 180 in the example shown here is carried out by heating elements 182. The heating elements 182 can be heat radiators. The joining tool could also be a convection oven instead. The support grid 184 has been omitted in Fig. 3. During heating, the temperature and duration are selected in the example shown such that the polymer material 131 of the polymer layer 130 melts at least enough to bond to the adjacent surfaces of the reinforcement layers 110 and 120.

[0103] Fig. 4 shows the layered composite 102 in the mold half 192, into which it was introduced by the conveying device 200. Also shown is a further mold half 194 of the forming tool 190. The two surfaces of the two mold halves 192 and 194 facing the layered composite 102 define the shape assumed by the layered composite 102 during the subsequent forming process under the action of force in the closed forming tool 190. The forming process in the forming tool 190 produces a sandwich layered composite semi-finished product, from which a sandwich layered composite structural component can be obtained through post-processing. This can, for example, be a layered composite structural component suitable for mounting on a motor vehicle below a traction battery.

[0104] Fig. 5 illustrates that a (sandwich) layered composite 102, 103 or a (sandwich) layered composite structural component 100, 101 obtainable in this way can have complex shapes. At least one part of the sandwich layered composite structural component 101 can, for example, form a cover, a base, or a wall of a housing, in particular a housing of an energy storage device, e.g., a battery or a tank.

[0105] The structural component 101 shown in Fig. 5 comprises different regions, each with a polymer layer 132, each comprising an expanded, porous layer region 134, as well as two reinforcement layers 110 and 120.

[0106] In the highly expanded layer composite area 129, additional reinforcement layers 112 and 122 are arranged on the reinforcement layers 110 and 120.

[0107] In other composite layer regions 127 and 128, only reinforcement layers 110 and 120 are arranged. In particular, in composite layer regions 127, in which no polymer layer 132 is present at all, but also in less expanded porous composite layer regions 128, in which the polymer layer 132 has a lower pore content than in more expanded porous composite layer regions 129, no additional reinforcement layers 112 and 122 are applied in the example shown here.

[0108] The structural component shown in Fig. 5 can be obtained with a polymer layer 132 that is foamable. The shaping step, i.e., changing the shape of the layered composite 102 by applying force in the shaping tool 190, comprises foaming in the layered composite regions 128 and 129 of the polymer layer 132. The foaming of the layered composite regions 128 and 129 is promoted by a force that moves the two surface regions of the polymer layer 132 adjacent to these layered composite regions 128 and 129 apart. The foaming of the layered composite regions 128 and 129 takes place within the shaping tool 190, which comprises a first and a second mold half 192 and 194, wherein the external force is applied by removing at least part of one mold half 194 from the other mold half 192.

[0109] Ribs 123 may be formed on at least one surface of a reinforcement layer 122. The surface of the reinforcement layer 120 may also include attached elements 125.

[0110] List of reference symbols

[0111] Layered composite structural component 100

[0112] Sandwich layer composite structural component 101

[0113] Layered composite 102

[0114] Sandwich layer composite 103

[0115] Layer arrangement 106

[0116] Sandwich layer arrangement 107

[0117] Reinforcement layer 110

[0118] Additional reinforcement layer 112

[0119] Reinforcement layer 120

[0120] Additional reinforcement layer 122

[0121] Rib 123 Connected element 125 Non-expanded composite layer area 127 Expanded composite layer area 128 Highly expanded composite layer area 129

[0122] Polymer layer 130

[0123] Polymer material 131

[0124] Polymer layer 132

[0125] Polymer material 133 porous layer area 134

[0126] Connecting tool 180

[0127] Heating element 182

[0128] Support grate 184

[0129] Forming tool 190

[0130] Mold half 192

[0131] Mold half 194

[0132] Conveyor device 200

Claims

Claims: Method for producing a layered composite (102), a layered composite semi-finished product or a layered composite structural component (100), wherein a layer arrangement (106) is provided, comprising a Reinforcing layer (110, 120), e.g., a fiber-reinforced reinforcing layer, and a polymer layer (130) arranged on a surface of the reinforcing layer, wherein the polymer layer (130) comprises a thermoplastic polymer material (131), the layer arrangement (106) is transformed into a layered composite (102) by heating, in which the polymer layer (130) comprises a deformable polymer layer (132), and the shape of the layered composite (102) is changed by applying force. A method according to claim 1 for producing a sandwich layered composite (103), a sandwich layered composite semi-finished product, or a sandwich layered composite structural component (101), wherein the provided layer arrangement (106) is a sandwich layered arrangement (107) in which the polymer layer (130) is arranged between the reinforcing layer (110, 120) and a further reinforcing layer (110, 120).A method according to claim 1 or 2, wherein the heating takes place in a joining tool (180) and the shape of the layered composite is changed in a forming tool (190). A method according to claim 3, wherein no active cooling of the layered composite (102) takes place between the joining tool (180) and the forming tool (190). A method according to claim 3 or 4, wherein an adaptation temperature difference AT, calculated by subtracting the mean forming tool temperature from the joining tool temperature, is at least 5 K, e.g., at least 40 K. A method according to any one of claims 3 to 5, wherein the temperature adaptation time t, which is determined by removing the layered composite (102) from the joining tool, is at least 5 K, e.g., at least 40 K. The time required for the tool (180) until the layer composite (102) is introduced into the forming tool (190) can be up to 150 seconds. A method according to any one of claims 3 to 6, wherein the adaptation temperature gradient G, which is calculated by dividing the adaptation temperature difference AT by the temperature adaptation time t, is in a range of 0.005 to 50 K / s. A method according to any one of the preceding claims, wherein, at the start of the force being applied to change the shape of the layer composite (102), a temperature inside the layer composite (102), e.g., inside the polymer layer (132), is higher than at a surface of the layer composite (102). A method according to any one of the preceding claims, wherein the heating conditions during heating, e.g., the duration and temperature during heating, and the temperature adaptation conditions, e.g.,The method coordinates the temperature of a medium, in particular air, extending around the layered composite (102), and the temperature adaptation time in this medium from the removal of the layered composite (102) from the joining tool (180) until the insertion of the layered composite (102) into the forming tool (190) such that a temperature inside the deformable polymer layer (132) exceeds a surface temperature of the layered composite (102) upon insertion of the layered composite (102) into the forming tool (190) by at least 5 K, e.g., at least 20 K. A method according to one of the preceding claims, wherein the layer arrangement (106) is provided without prior heating of the reinforcing layer (110, 120). A method according to one of the preceding claims, wherein the surface of the layer arrangement (106) reaches a temperature of at least 5 K upon heating, e.g., 10 K to 100 K, above the melting temperature of the polymer material (131) contained in the polymer layer (130). A method according to any one of the preceding claims, wherein the reinforcement layer also comprises a polymer material (133). A method according to claim 12, wherein the reinforcement layer (110, 120) is a fiber-reinforced reinforcement layer and the polymer material (133) encompassed by the reinforcement layer is in contact with surfaces of fibers of the reinforcement layer. A method according to claim 12 or 13, wherein, at the start of the force to change the shape of the layered composite (102), the temperature inside the layered composite (102) is at or above, preferably above, the melting temperature of the polymer material (131) encompassed by the polymer layer, and the temperature at a surface of the layered composite (102) is at or below the melting temperature of the polymer material (133) encompassed by the reinforcement layer (110, 120).Method according to one of claims 12 to 14, wherein the melting temperature Tsv of a polymer material (133) encompassed by the reinforcement layer (110, 120) is:. TSV > TSP — 20K, where TSP is the melting temperature of the polymer material (131) encompassed by the polymer layer (132). A method according to any one of the preceding claims, wherein the polymer layer (132) is foamable and the shaping step comprises foaming at least one region of the polymer layer (132). A method according to claim 16, wherein the foaming of the region is promoted by a force that separates the two surface regions of the polymer layer (132) adjacent to that region. A method according to claim 17, wherein the foaming of the region takes place within a shaping tool (190) comprising a first and a second mold half (192, 194) and the external force is applied by removing at least a part of one mold half (192, 194) from at least a part of the other mold half (192, 194). Layer composite (102), layer composite semi-finished product or layer composite structural component (101), preferably obtainable according to one of the methods of claims 1 to 18, wherein the polymer layer (132) has a porous layer region (134). Layer composite (102), layer composite semi-finished product or layer composite structural component (100) according to claim 19, wherein the porous layer region (134) is spaced apart from the reinforcement layer (110, 120) and has a lower density than a region of the polymer layer (132) located between the porous layer region (134) and the reinforcement layer.

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