METHOD FOR MANUFACTURING A CLADDING PART FOR A VEHICLE AND A CLADDING PART MANUFACTURED THEREBY

Description

[0001] The invention relates to a method for producing a trim part, in particular for the interior of a vehicle, in which method a carrier substrate is positioned opposite a flexible decorative layer with the interposition of a foam layer and adhesively bonded thereto. Also described is an interior trim part produced by this method, wherein the raw material used to form the foam layer, foamed with a gas as a physical blowing agent, is applied to the back of the decorative layer and / or the side of the carrier substrate facing the decorative layer as a reactive expanded foam raw material.

[0002] Such trim parts are found as interior trim components in motor vehicles, for example, in the form of instrument panel covers, door panels, glove compartments, and the like. Such trim parts are also used outdoors, for example, on boats. Such trim parts comprise a rigid carrier substrate that is attached to the vehicle chassis. The carrier substrate can serve to support attachments or add-on parts, for example, electrical / electronic units. Such a carrier substrate is typically a plastic injection-molded part made of PP or ABS. The visible side of such an interior trim part is formed by a decorative layer. The decorative layer is flexible and can also have elastic properties, especially if it is a plastic layer, for example made of polyurethane.To give the trim part a soft-touch feel, an elastic, soft foam layer is placed between the decorative layer and the carrier layer. The thickness of such a foam layer is usually only a few millimeters, typically 3 to 8 mm. The feel provided by the foam layer, and thus its hardness, is largely determined by the choice of the raw foam mass, its degree of expansion, and the density of the foam layer.

[0003] In the classic back-foaming process for producing such a trim part, the decorative layer is inserted into an open, multi-part mold or created by injecting a plastic compound into one mold half. A reactive foam-forming raw material is then applied to the back of the decorative layer. The mold is then closed, with the other half supporting the carrier substrate. In the closed mold, a predefined gap is left between the carrier substrate and the decorative layer. The reactive foam-forming raw material contains a chemical blowing agent, water. As a result of the reaction between the foam-forming components—in the case of polyurethane, these are the polyol and isocyanate components—the raw material is polymerized and simultaneously foamed due to an isocyanate-water reaction that releases gas.At the end of the crosslinking process, the foam layer is formed between the decorative layer and the carrier substrate. At the same time, the crosslinking process is used to adhesively bond the foam to both the decorative layer and the carrier substrate. Adhesion promoters can support the adhesive bonding of the foam layer to the decorative layer and the carrier substrate. Flexible polyurethane foams with densities between 150 and 200 kg / m³ are typically used to form such foam layers, for example, in a vehicle interior trim part.

[0004] It must be taken into account in this manufacturing process that during the chemical foaming and the accompanying polymerization, sometimes very high pressures and temperatures are generated within the mold. This not only places high demands on the molds and mold parts used for this purpose, but it is also important to note that the decorative layer must have a properties that can withstand these influences, especially the temperatures, even if there may be different temperature distributions in the mold. This must not result in a temperature-dependent change in the appearance of the visible side of the decorative layer. If materials with openings are used as decorative layers in this process, the pressures of up to 2 - 5 bar prevailing in such a mold can lead to foam breakthroughs, whereby foam is pressed onto the visible side of the decorative layer.Therefore, when using such materials to provide the decorative layer, it is sometimes necessary to carry out complex sealing measures before applying the reactive, not yet expanded raw material.

[0005] DE 10 2011 005 343 A1 discloses a method for producing such a trim part in an open mold. This method utilizes a low-energy foam system, i.e., a foam system that does not generate significant pressure. The aggregate state of the reactive foam mass applied to the back of the decorative layer is selected so that it does not flow after application. This is done so that the foam mass does not penetrate any openings in the decorative layer. If bonding of the carrier substrate without additional adhesion promoters or other adhesives is desired, this can be pressed into the surface of the foam mass once the foaming process is complete, or at least largely complete. However, the so-called tack-free time of the foam mass must not yet have been reached at the time of mounting the carrier substrate.Finally, the foam surface must still be sticky enough to enable the desired adhesive bond.

[0006] From DE 20 2008 017 784 U1, an interior trim part with absorbent decorative material is known. According to the method described in this prior art for producing such an interior trim part, a partially physically expanded foam mass is applied. This contains, as is known per se, a chemical blowing agent. To allow foam to be applied to an absorbent decorative material without it penetrating through, it is provided that some time is initially allowed after application of the foam mass until the viscosity is sufficiently high due to an already advanced crosslinking process that prevents the foam mass from being forced through the decorative layers upon attachment of the carrier substrate. In this respect, the method described in this prior art does not differ from the method described in DE 10 2011 005 343 A1.

[0007] DE 10 2015 201 898 A1 discloses a method and device for producing an undercut molded part. A reactive plastic is applied to a paint layer, onto which the support structure is subsequently positioned. The support structure, which is held in a mold at a certain distance from the paint layer, is positioned after the reactive plastic has begun to foam. Further foaming fills the remaining air gap between the support structure and the reacting plastic.

[0008] DE 10 2010 023 034 A1 describes a process in which a decorative layer is inserted into a lower mold and a reinforcement device with spacers is inserted into a second mold. In a subsequent step, the molds are moved together so that both elements are at their intended distance from each other. The area between the decorative layer and the carrier part is then filled with foam.

[0009] Even though this previously known process allows for the back-foaming of decorative layers with openings, the time window in which the carrier substrate is pressed into the not yet fully cross-linked foam surface must be precisely adjusted and adhered to. Ultimately, the applied foam-forming raw material should be almost completely foamed before the carrier substrate is brought into contact with it. Furthermore, the foam's tack-free time, i.e., the point at which the foam is no longer sticky, must not yet have been reached. This time window is usually only a few seconds. When the carrier substrate is pressed into the expanded, almost fully polymerized foam, the foam is compressed.The latter leads to varying hardness across the surface of the interior trim part, and thus to varying haptics across the surface, if the distance between the back of the decorative layer and the carrier substrate, and thus the thickness of the foam layer, is not uniform across the surface of the interior trim part. The hardness of the foam layer is then greater in those areas of the interior trim part where the distance between the decorative layer and the carrier substrate is smaller. This applies in particular to carrier substrates that cannot be provided at a uniform distance from the decorative layer due to other requirements. This can be compensated for, if at all, only very inadequately by applying the foam-forming raw material in varying thicknesses.

[0010] A method according to the preamble of claim 1 is known from DE 10 2005 052 344 A1.

[0011] Based on this discussed prior art, the invention is therefore based on the object of proposing a method for producing an interior trim part having a flexible foam layer between a decorative layer and a carrier substrate, which avoids the disadvantages outlined above and, moreover, less restricts the design freedom for the layout of such an interior trim part. Furthermore, it would be desirable if the manufacturing process could be simplified and, in particular, shortened in time.

[0012] This problem is solved by a generic method as mentioned above with the features of claim 1.

[0013] In this process, the foam raw material is applied in an expanded state, either to the back of the decorative layer or to the side of the carrier substrate facing the decorative layer, or to the decorative layer and the carrier substrate. Since the foam raw material is applied in its already foamed state, two such foam application layers can be applied, one to the back of the decorative layer and the other to the side of the carrier substrate facing the decorative layer, and still produce a homogeneous foam layer. The blowing agent used is a physical blowing agent, namely a gas such as carbon dioxide or nitrogen. It goes without saying that other suitable gases can also be used as a blowing agent.In contrast to conventional processes in which the raw material is foamed with chemical blowing agents, this does not arise from a chemical reaction within the applied raw material. The foam application is open-pored. A combination of this already expanded foam application with other foam applications and / or foam layers is also possible, for example if a first foam application is applied to the back of the decorative layer, for example as an open-pore foam application, as described above, and a second foam application is applied to the side of the carrier substrate facing the decorative layer as a closed-pore foam application or has been connected to the carrier substrate by another process. Such a combination can also be carried out by coating the back of the decorative layer with a foam layer in a first step before the expanded foam application according to the invention is applied.In order to keep the carbon footprint low during the production of such a trim part, it is preferable to use nitrogen, for example, rather than carbon dioxide as the gaseous propellant.

[0014] Since the foam is applied in an expanded state, the carrier substrate can be positioned opposite the decorative layer immediately after the expanded foam has been applied. When foam is applied to the back of the decorative layer, this means that the carrier substrate is brought into contact with the expanded foam applied to it. Regardless of whether the foam is applied to the decorative layer and / or the carrier substrate, unlike previously known methods, there is no need to wait for the time required for chemical foaming to elapse before positioning the carrier substrate. With previously known methods for positioning the carrier substrate, it is also necessary to wait until the cells formed by the foaming process have burst so that an open-pore foam layer is formed.In conventional processes, positioning the carrier substrate too early is therefore also determined by the time at which the open-pore foam forms.

[0015] Since, in the subject matter of the claimed method, the carrier substrate has only just begun to polymerize at the time of positioning the foam layer relative to the decorative layer, the foam layer is still fluid to at least a certain extent and can be easily displaced. This is achieved by positioning and aligning the carrier substrate relative to the decorative layer. The process then takes place until the curing process is at least largely complete before the trim part is removed from the mold. Displacing expanded foam offers numerous advantages.This can, for example, even out the expanded foam, which is typically applied by spraying, within the mold gap between the decorative layer and the carrier substrate, as well as displacing expanded foam not required to fill this gap from the mold gap. Of interest to the trim part to be manufactured in this context is that, regardless of the material thickness of the foam layer between the decorative layer and the carrier substrate, the trim part is backed with a uniform hardness even if the gap width varies. This prevents unwanted foam compression, at least not to a noticeable extent. A foam compression of 5-30%, preferably 10-20%, in particular 10-15%, is factored into the formation of the foam layer and is therefore not undesirable.

[0016] A key feature of this process is that the time interval in which the carrier substrate must be positioned relative to the decorative layer is significantly longer. For example, in the case of a foam coating on the back of the decorative layer, the carrier substrate must be brought into contact with the foam layer for adhesive bonding. This not only shortens the manufacturing process by eliminating the need for waiting, as is the case with the use of chemical blowing agents, but also provides a process that is less susceptible to long-term reproducibility. Furthermore, the use of catalysts in the reactive foam mass can significantly shorten the reaction time—the time required until the polymerization process is complete—so that the production of such a trim part can be shortened even further.When using chemical blowing agents, the crosslinking process should not begin until the expansion process is complete. If, for example, the back of the decorative layer is provided with the expanded foam application in the method according to the invention, the carrier substrate is typically brought into contact in the time window of the reaction time after 70% of the reaction time has not yet been reached. The same applies if the carrier substrate is coated or if foam is applied to the decorative layer and the carrier substrate. A particularly preferred embodiment is one in which the carrier substrate is positioned when 50% of the reaction time has not yet elapsed. The earlier in relation to the reaction time the carrier substrate is positioned relative to the decorative layer with the foam application interposed, so that the foam application contacts both the decorative layer and the carrier substrate, the better the adhesive bond.Due to this early positioning of the carrier substrate relative to the decorative layer with the expanded foam layer interposed, compared to the prior art, the polymerization process is not yet sufficiently advanced for foam movement to occur without damaging the foam structure. This is cleverly utilized in the subject matter of the invention.

[0017] The relatively large time window for positioning the carrier substrate also allows the production of larger cladding parts, where the application of the expanded foam, typically by spraying, requires some time, without having to accept disadvantages with regard to the positioning of the carrier substrate relative to the decorative layer in terms of the foam quality or an adhesive bond of the foam application to the decorative layer and the carrier substrate.

[0018] The possibility of displacing a portion of the expanded foam layer through the carrier substrate allows the foam layer to be applied with a greater thickness than actually required, and thus with a larger volume than necessary. This is provided for in a preferred embodiment. The distance between the decorative layer and the carrier substrate can be provided by spacer elements, for example spacer pins, for example as part of the carrier substrate or integrated into the mold. The use of a positioning caliber is also entirely possible. The displacement of a certain amount of expanded foam layer and thus the modeling orDistributing the foam application through the carrier substrate by a relative movement between the carrier substrate and the decorative layer leads to a foam that is homogeneous in terms of its compression in the space between the decorative layer and the carrier substrate with consistent foam quality.

[0019] In this process, the flowable nature of the expanded foam layer at the time of positioning the carrier substrate relative to the decorative layer allows this property to be used to introduce foam into undercuts in the carrier substrate. This has the advantage that the polymerized foam layer is then bonded to the carrier substrate not only adhesively but also by form-fitting. This is especially true when the foam layer is applied to the back of the decorative layer and not to the carrier substrate. Simply pressing the carrier substrate into the expanded foam layer presses it into the undercut structures present on the carrier substrate on its side facing the foam layer.To support such foam application intervention into undercut structures of the carrier substrate on its side facing the decorative layer, the carrier substrate can also be moved in the plane of the decorative layer, floating on the foam layer. The term "flowability" of the foam layer used in this context after polymerization has begun does not necessarily mean that the foam must flow solely due to gravity, but rather that it is moldable and thus movable without any significant change in its consistency. A certain degree of compression is possible.

[0020] Excess foam can be pressed out laterally from the space between the decorative layer and the carrier substrate and cut off, for example, after the crosslinking process of the foam application has been completed. In order to avoid excessive squeezing out of expanded foam with such a configuration of the method, when applying the expanded foam in the peripheral edge region of the decorative layer or also peripherally around access openings made therein, the foam can be applied with a smaller thickness or with a thickness that decreases towards the edge or the access opening. According to another configuration, it is provided that the mold and / or the carrier substrate has openings or channels at the edges through which the foam displaced by the positioning of the carrier substrate can escape from the gap between the decorative layer and the carrier substrate.It is also possible that, if the foam application is not to be displaced from the space between the decorative layer and the carrier substrate, or not completely displaced, in response to the carrier substrate being pressed in, the foam application is compressed by pressing in the carrier substrate. Compressing the foam application is desirable if its density is also to be influenced. This is possible with the process described because open-pored expanded foam was applied to form the foam application. The gas contained in the foam cells can be forced from one cell to the next and thus also out of the foam application. This measure plastically compresses the foam application. If foam escape from the space between the decorative layer and the carrier substrate is not desired, this space can be sealed at the edges.

[0021] A further particular advantage of this process is that, due to the desired flowability, the foam can be applied by spraying. This is provided in a preferred embodiment, with the spray application being carried out with a small droplet size, which allows for particularly good control of the application thickness of the expanded foam.

[0022] As a result of the application of a pre-foamed foam layer, no additional temperature is introduced into the composite being created. Conventional processes typically use water as a chemical blowing agent. The resulting reaction is exothermic. Since the claimed foaming process does not require an exothermic reaction, shrinkage phenomena do not need to be considered or accepted. Furthermore, cell-opening agents are not required as additives in the foam base mass in the claimed process.

[0023] This production of a trim component takes place without pressure. The application pressure is generally less than 1 bar, preferably even less than 0.5 bar.

[0024] Furthermore, polymerization can be carried out at low temperatures, at least at temperatures that do not adversely affect the decorative layer.

[0025] The thickness of the foam layer produced in this way can easily be 15 mm to 20 mm, in particular up to 10 mm, and even more particularly up to 5 mm. Thickness differences in the space between the decorative layer and the carrier substrate can occur due to the plastic moldability of the foam application.

[0026] The density of the foam coating is freely selectable and can, for example, be between 70 and 700 kg / m³, and in particular between 200 and 500 kg / m³. Typically, positioning the carrier substrate relative to the decorative layer involves a certain degree of compression of the foam coating. This can increase the foam coating density by, for example, 5% to 30%.

[0027] Preferred densities of the foam application are approximately 250 kg / m 3< , whereby this can be increased by positioning the carrier substrate, which is accompanied by compression of the foam application, to, for example, 300 kg / m 3< .

[0028] In this process, the space between the decorative layer and the carrier substrate forms the mold within which the foam application polymerizes and thus takes on its desired shape.

[0029] The foam layer formed from the foam application after completion of polymerization can be designed as a flexible foam layer or as a semi-rigid foam layer, depending on the desired requirements.

[0030] Typically, the carrier substrate is positioned immediately after the expanded foam has been applied. Since polymerization begins upon mixing the reactive components—in the case of polyurethane, polyol and isocyanate—polymerization and thus the reaction time have already begun at this point. However, as already shown above, this does not affect foam displacement by the carrier substrate.

[0031] Even though the process described above can in principle be carried out in a closed mold without pressure and without exothermic heating, it is typically carried out in an open mold for the sake of simplicity.

[0032] In a preferred embodiment, a water-free foam raw material is spray-applied with a gaseous propellant.

[0033] Even if the application of a water-free expanded foam coating is provided for in the embodiment described above, it is possible that a chemical blowing agent may also be contained in the foam coating to a certain extent in order to achieve certain effects.

[0034] The foam layer of the manufactured trim part is typically a polyurethane foam. The gas can be mixed in before or during the mixing of the polyol component with the isocyanate component. It is also possible to add gas to one of the two components before they are mixed. In a spray application, gas, typically nitrogen, is added to the reactive mixture in the mixing chamber. The actual volume increase occurs at the outlet of the application nozzle, so that the expanded foam is applied to the back of the decorative layer. WO 2007 / 127623 A1 describes a spraying process. The statements in this prior art concerning spray application, even if carried out in a different context, are hereby incorporated by reference.It goes without saying that other polymerizing foams can also be used to form the foam layer of the cladding part.

[0035] The decorative layer can ultimately be any flexible film-like layer, such as a thermoplastic film, one made of polyurethane, PVC, TPO, fabric, leather, synthetic leather, or the like. Pressure- and temperature-sensitive materials can also be used without any problems, as neither pressure nor elevated temperatures are generated during this process. Such a decorative layer can also have openings. Foam penetrations adhering to the visible side of the decorative layer are not a concern due to the lack of pressure during foam application.

[0036] The carrier substrate can, as is the case with conventional processes, be PP or ABS plastic parts, for example. These can have openings, which is unproblematic due to the pressureless application and polymerization. Foam can indeed be pressed into openings in the carrier substrate. However, these do not represent pathways through which foam could escape under pressure, as would be the case with previously known processes using closed molds. For this reason, the application of semi-rigid expanded foam also allows the use of carrier substrates that are perforated or permeable overall, thus exhibiting a certain degree of permeability. Thus, the carrier substrate can also be fiber mats, such as glass fiber mats or mats made from natural fibers.During the positioning of the carrier substrate relative to the decorative layer, the foam coating can be incorporated into such a carrier substrate so that it is embedded in the foam. The carrier substrate is then positively bonded to the foam layer after the polymerization process is complete.

[0037] In the method described above, it is certainly possible for the foam layer to be constructed from two or more individual foam sub-layers that differ from one another, for example, in their density. Each of these foam layers is applied as an expanded foam layer. This does not preclude the previously described embodiment, in which such a foam layer is formed from individual foam sub-layers and is itself applied to a foam layer, as part of the decorative layer, or as part of the carrier substrate.

[0038] The invention is described below using an exemplary embodiment with reference to the accompanying figures. They show: Fig. 1: In a schematic representation of an open mold for producing a vehicle interior trim part with a decorative layer therein, Fig. 2: the shape of the Figure 1 with the decorative layer inside, back-foamed with an expanded foam application, Fig. 3a, 3b: a carrier substrate to be positioned on top of the foam application ( Figure 3a ) and the carrier substrate positioned on the foam application ( Figure 3b ), Fig. 4: the interior trim part removed from the mold, Fig. 5: a diagram to show the time course of the individual process steps in the production of the interior trim part of the Figure 4 , Fig. 6: a diagram corresponding to that of the Figure 5, to illustrate the time sequence of an interior trim part also produced in an open mold according to the state of the art, Fig. 7a-7c: a partial sectional view through the arrangement of an open mold with a carrier substrate to be positioned, which has an opening for forming an opening within the cladding part ( Figure 7a ), the carrier substrate positioned opposite the decorative layer with the foam application interposed ( Fig. 7b ) and the trim part removed from the mold with the opening formed in it and Fig. 8a-8c: a partial representation corresponding to the representations in Figures 7a-7c with a different design of the opening formation of the interior trim part.

[0039] An open mold 1 comprises a cavity 2. A decorative layer 3 is arranged in the cavity 2. In the illustrated embodiment, the decorative layer 3 is preformed in the mold 1, specifically in the illustrated embodiment by spraying on a suitable polyurethane mass. The side of the mold 1 facing the cavity 2 is structured with a leather-like grain, so that the decorative layer 5 can be Figure 1 To form an interior trim part for a vehicle, in the illustrated embodiment, a reactive expanded foam raw material is applied to the back of the decorative layer 3 in a subsequent process step, namely by spraying. The droplet size emerging from the spray nozzle is relatively small, for example 0.1 to 1 mm. In the illustrated embodiment, the foam application 4 is expanded polyurethane flexible foam. The foam application is in Figure 2identified by the reference numeral 4. The foam application of the illustrated embodiment is an open-pore polyurethane flexible foam, which has been foamed with nitrogen and applied in the foamed state to the decorative layer 3. Immediately after application of the foam application 4, i.e. at a time when the reaction time with regard to its polymerization process has just begun, a carrier substrate 5 is brought into contact with the upper side of the foam application 4 and slightly pressed into it (see Figure 3a , 3b). In the illustrated embodiment, the carrier substrate 5 is a rigid ABS plastic part. Pressing the carrier substrate 5 into the foam layer 4 serves to distribute the foam in the gap (cavity) between the decorative layer 3 and the carrier substrate 5 and to introduce it into undercut structures of the carrier substrate 5 facing the decorative layer 3. Such undercut structures are identified on the carrier substrate 5, for example, in the form of dovetail-shaped undercuts and are identified by the reference numeral 6. The formation of these undercut structures serves the purpose of connecting the carrier substrate 5 to the polymerized foam layer not only adhesively but also in a form-fitting manner. In the illustrated embodiment, the carrier substrate 5 is structured and has a projection 7 which is pressed deeper into the foam layer 4 than the sections adjacent to the projection 7.The flowability or mobility of the foam application 4 at the time of its joining with the carrier substrate 5 is utilized.

[0040] The carrier substrate 5 is pressed into the foam layer 4 until the predefined distance to the decorative layer 3 is established. In the illustrated embodiment, the carrier substrate 5 has stop extensions which rest against the upper side of the mold 1 when the predefined distance to the decorative layer 3 is reached. The foam layer 4 has been applied with a volume that is larger than the actually required volume in order to fill the gap between the decorative layer 3 and the carrier substrate 5 in the Figure 3bshown position. Excess foam is pressed out of the cavity 2 of the mold laterally (see Figure 3b). This is accompanied by a certain compression of the foam layer 4, which is easily possible since this is an open-pore foam layer. After positioning the carrier substrate 5, the process waits until the polymerization process is complete. The finished interior trim part 8 is then removed from the mold 1, cleaned if necessary, and can then be further processed or assembled. The interior trim part 8 is in Figure 4 The polymerized foam layer is identified by reference numeral 9.

[0041] The chronological sequence of the process steps in relation to the chemical behavior of the expanded foam application is shown in the diagram of the Figure 5 In the diagram of the Figure 5Time is plotted on the x-axis and the foam volume on the y-axis. Since expanded foam is applied in the method described above, the foam volume remains constant over time. The foam volume does not necessarily change due to the displacement process described above when positioning the carrier substrate 5. Nevertheless, it can be provided that pressing in the carrier substrate 5 causes a certain compression of the foam application 4, typically by 8-15%. At time (1), the expanded foam has been applied by spraying. The reaction time of the reactive foam begins with the foam application.Since the back of the decorative layer 3 cannot be sprayed over its entire surface at the same time, the reaction time has begun, distributed at different times across the surface of the back of the decorative layer 3, before the carrier substrate 5 is brought into contact with the expanded foam application and positioned at time (2). The time window in which the carrier substrate 5 is intended to be positioned ends at time (3). In the diagram, the tack-free time is reached at time (4). Then the surface of the foam application 4 is no longer tacky. For this reason, the intended time window ends with a sufficient time interval before time (4). In the illustrated embodiment, the reactive foam application 4 is adjusted by the addition of catalysts so that the tack-free time is reached after only about 25 seconds.This leaves a time window of approximately 15 to 20 seconds for positioning the carrier substrate with this process. If the expanded foam application is configured differently, namely by slightly extending the reaction time until the tack-free time, the time window for positioning the carrier substrate is correspondingly longer. The time window can be adjusted accordingly. The area of ​​the back of the decorative layer 3, to which the foam layer 4 is to be applied, can also influence the dimensioning of this time window. A larger area requires more time for foam application.

[0042] The Figure 6The diagram shown shows the process sequence for producing an interior trim part when the reactive, not yet expanded raw material is applied to the back of a decorative layer in an open mold. To position the carrier substrate, the foaming process must first be waited for, until it is completely or almost completely finished. Therefore, time (2) is necessarily much later in terms of reaction time than in the Figure 5shown process sequence in the process according to the invention. The time window in which the carrier substrate is to be positioned (time interval between (2) and (3)) is very short due to the proximity of the non-stick period when the polymerization process is largely advanced. Positioning the carrier substrate too early when brought into contact with the foam surface leads to the formation of a harder foam. Positioning the carrier substrate too late no longer leads to the desired quality of the adhesive bond. Finally, the non-stick period is reached shortly thereafter at time (4). Although it is possible to shorten the reaction time in this process as well by using catalysts, this also reduces the time window within which the carrier substrate is to be positioned.Therefore, in this process, the reaction time of the foam-forming raw material will be adjusted so that the time window for positioning the carrier substrate is sufficiently long.

[0043] Figure 7a shows a section of a mold 1.1 in which a decorative layer 3.1 has been inserted or formed on the molding surface of the mold 1.1. The mold 1.1 is designed so that the interior trim part to be produced with it can be manufactured with an opening, for example for inserting the air outlet panel of an air conditioning system. For this purpose, the mold 1.1 has a projection 10 providing a weak point in the foam layer to be created. The projection 10 extends circumferentially around the opening to be created and tapers towards the carrier substrate 5.1. The carrier substrate 5.1 has an opening 11 in the region of the opening to be created.

[0044] After spraying the back of the decorative layer 3.1 with expanded foam to provide a foam coating, the carrier substrate 5.1 is positioned opposite the decorative layer 3.1. In the area of ​​the projection 10, the distance between the carrier substrate 5.1 and the decorative layer 3.1 is minimized. This means that the thickness of the foam coating 4.1 in the gap between the projection 10 and the carrier substrate 5.1 is very small. For the purpose of connecting the carrier substrate 5.1 to the decorative layer 3.1, a foam coating is located between the decorative layer 3.1 and the carrier substrate 5.1. By positioning the carrier substrate 5.1 on the foam coating 4.1 (see Figure 7b) foam application has also been pressed into the opening 11. After completion of the polymerization process, caused by the projection 10, a predetermined breaking point is provided, at which the polymerized foam application - the foam layer 9.1 - with the attached decorative layer 3.1 is separated out towards the center of the opening to be created (indicated by the dashed line), for example by tearing. This is typically done after the interior trim part 8.1 has been removed from the mold 1.1. In the opening 12 of the interior trim part 8.1 created in this way (see Fig. 7c ) an additional component can then be mounted which passes through the interior trim part 8.1.

[0045] Figure 8a shows a design of the components according to the embodiment of the Figures 7a-7c , whereby in the embodiment of the Figure 8athe carrier substrate 5.2 carries a projection 13 with a tip pointing towards the mold 1.2. In the Figures 8a, 8b In the embodiment shown, the mold 1.2 also has a projection 10.1, which, however, unlike the projection 10 of the mold 1.1, which tapers towards the carrier substrate 5.1, has a plateau 14. The interior trim part 8.2 is manufactured with the mold 1.2 in the same way as described above for the embodiment of the Figures 7a-7c After polymerization of the foam layer 4.2, which provides the foam layer 9.2, the polymerized foam is removed from the area of ​​the opening 12.1 to be created, along with the decorative layer 3.2 adhering to it, to release the opening 12.1.

[0046] The invention has been described using an exemplary embodiment. Without departing from the scope of the applicable claims, numerous further possibilities for implementing the invention will become apparent to a person skilled in the art without the need for detailed explanation within the scope of these statements. Reference symbol list

[0047] 1, 1.1, 1.2 Mold 2 Cavity 3, 3.1, 3.2 Decorative layer 4, 4.1, 4.2 Foam application 5, 5.1, 5.2 Carrier substrate 6 Undercut structure 7 Projection 8, 8.1, 8.2 Interior trim part 9, 9.1, 9.2 Foam layer 10, 10.1 Projection 11, 11.1 Opening 12, 12.1 Opening 13 Projection 14 Plateau

Claims

1. Method for producing a lining part (8, 8.1, 8.2), in particular for the interior of a vehicle, with which method a support substrate (5, 5.1, 5.2) is positioned opposite a flexible decorative layer (3, 3.1, 3.2) with the interposition of a foam coating (4, 4.1, 4.2), and the support substrate is adhesively connected thereto, wherein the raw foam compound used to form the foam layer (9, 9.1, 9.2) is foamed using a gas as a physical blowing agent and is applied onto the rear face of the decorative layer (3, 3.1, 3.2) and / or the face of the support substrate (5, 5.1, 5.2) facing towards the decorative layer (3, 3.1, 3.2), in the form of a reactive expanded raw foam compound, characterised in that, as long as the expanded foam coating (4, 4.1, 4.2) is still flowable, the support substrate (5, 5.1, 5.2) is positioned at a defined distance to the rear face of the decorative layer (3, 3.1, 3.2), with the interposition of the expanded film coating (4, 4.1, 4.2), wherein, during the process of positioning of the support substrate (5, 5.1, 5.2), at least in some regions, a part of the foam coating (4, 4.1, 4.2) filling the original distance between the decorative layer (3, 3.1, 3.2) and the support substrate (5, 5.1, 5.2) is displaced and plastically compressed, such that the decorative layer (3, 3.1, 3.2) is connected to the support substrate (5, 5.1, 5.2) by the foam coating (4, 4.1, 4.2), and is held until the cross-linking process of the foam coating (4, 4.1, 4.2) has at least mostly concluded.

2. Method according to claim 1, characterised in that the support substrate (5, 5.1, 5.2) is positioned opposite the decorative layer (3, 3.1, 3.2) in the reaction time interval when 70% of the reaction time, in particular 50% of the reaction time, has not yet been exceeded.

3. Method according to claim 1 or 2, characterised in that the expanded foam coating (4, 4.1, 4.2) is applied in a volume which is greater than the volume required for filling the gap between the decorative layer (3, 3.1, 3.2) and the support substrate (5, 5.1, 5.2).

4. Method according to any one of claims 1 to 3, characterised in that the support substrate (5, 5.1, 5.2) is moved, in relation to its distance from the decorative layer (3, 3.1, 3.2) and in relation to its position to the flat surface extension of the decorative layer (3, 3.1, 3.2), opposite the expanded foam coating (4, 4.1, 4.2) applied onto it, before the support substrate (5, 5.1, 5.2) is held until the at least very largely completed completion of the cross-linking process of the foam coating (4, 4.1, 4.2).

5. Method according to any one of claims 1 to 4, characterised in that the support substrate (5, 5.1, 5.2) is positioned, by means of spacer elements or by means of a positioning calibre, on which the support substrate (5, 5.1, 5.2) is positioned, on the rear of the decorative layer (3, 3.1, 3.2) in relation to the distance interval of the support substrate (5, 5.1, 5.2) to the rear of the decorative layer (3, 3.1, 3.2).

6. Method according to any one of claims 1 to 5, characterised in that the process steps are carried out in an open mould (1, 1.1, 1.2), wherein, in a first step, the decorative layer (3, 3.1, 3.2) are laid in the mould or are produced in it, and the further steps then follow on from this in the open mould (1, 1.1, 1.2).

7. Method according to any one of claims 1 to 6, characterised in that the application of the expanded raw foam compound takes place wholly or partially onto a side of the decorative layer facing towards the substrate, or onto the foam layer arranged on the side of the support substrate facing towards the decorative layer.

8. Method according to any one of claims 1 to 7, characterised in that the foamed expanded foam coating (4, 4.1, 4.2) is applied by spraying.

9. Method according to any one of claims 1 to 8, characterised in that, for the formation of the foam layer (9, 9.1, 9.2), a reactive foamed expanded polyurethane raw foam compound is applied, for the formation of, in particular, a polyurethane flexible foam or a semi-rigid polyurethane foam as a foam coating (4, 4.1, 4.2).

10. Method according to claim 9, characterised in that the blowing agent is introduced into the reaction compound before and / or during the mixing process or into the polyol and / or the isocyanate components used for the production of the reaction compound.

11. Method according to any one of claims 9 or 10, characterised in that the raw foam compound to be applied, which is foamed by the blowing agent, is free of water, or at least free of water to the greatest possible extent.

12. Method according to any one of claims 1 to 11, characterised in that the support substrate (5.1, 5.2) (5.1, 5.2) has at least one passage opening, and the lining part (8.1, 8.2) is produced with a predetermined break point in order to produce a passage opening (12, 12.1).

13. Method according to any one of claims 1 to 12, characterised in that the support substrate is permeable to the expanded foam layer, and that, due to the positioning of the support substrate in relation to the decorative layer, with the interposition of the expanded foam coating, foam material is introduced into the support substrate.

14. Method according to claim 13, characterised in that a fibre mat is used as the support substrate.

15. Lining part, in particular an interior lining part for a vehicle, produced in accordance with any one of claims 1 to 14, characterised in that the lining part (8, 8.1, 8.2), by means of its flat surface extension and, despite there possibly being different gap dimensions present between the decorative layer (3, 3.1, 3.2) and the support substrate (5, 5.1, 5.2), it has a homogenous hardness of its foam layer (9, 9.1, 9.2).