METHOD FOR PRODUCE A TRANSPARENT INTERIOR SURFACE FOR A VEHICLE AND TRANSPARENT INTERIOR SURFACE FOR A VEHICLE

Abstract

The invention relates to a method for producing a translucent interior surface (28) for a vehicle, comprising the steps of: providing a perforated decorative layer (10) with an opening (12) or a plurality of openings (12) extending from a back side (14) of the decorative layer (10) to a visible side (16) of the decorative layer (10); covering the visible side (16) of the decorative layer (10) with a cover layer (20) covering the through-holes; providing a translucent, non-reactive filler (22) that cures reversibly or irreversibly; applying the provided filler (22) to the back side (14) of the decorative layer (10) covered by the cover layer (20) before it has cured, wherein the openings (12) are filled with the filler by applying pressure to the filler (22);Removing the cover layer (20) from the visible side (16) of the decorative layer (10) after the openings (12) have been filled with the filler material (22) and the filler material (22) has hardened at least in its area facing the cover layer (20). The invention further relates to a translucent interior surface (28) for a vehicle.

Description

Technical area

[0001] The present invention relates to a method for producing a translucent interior surface for a vehicle and a translucent interior surface for a vehicle. State of the art

[0002] Ambient lighting is becoming increasingly common in vehicle interiors, especially in motor vehicles. To create a visually and tactilely appealing surface, components or areas within the vehicle interior are often covered with decorative layers, which then form an interior surface with their visible side facing the vehicle interior.

[0003] To implement such ambient lighting even in areas with non-transparent or barely translucent decorative layers, these decorative layers are perforated and illuminated with backlighting. When the backlighting is activated, light emerges from the decorative layer at the perforated points on the visible side facing the vehicle interior. Penetrated by light, a wide variety of ambient lighting or lighting effects can be achieved on the interior surface formed by the visible side of the decorative layer, for example, patterns, motifs in the form of logos or crests, switch symbols, and the like.

[0004] However, the perforations in the decorative layer, which are inherently non-transparent or only poorly translucent, can become clogged with foreign particles over time, which can impede long-term, good, and even homogeneous illumination. Filling the perforated openings in the decorative layer with a translucent material could solve the clogging problem. However, achieving a high-quality, visually and tactile surface finish on the visible side is particularly difficult.

[0005] Conventional filling compounds are often formulated as two-component compounds, the main component of which is mixed with an isocyanate-based crosslinker component for improved temperature resistance (in the automotive sector, interior components are required to be temperature-resistant up to 140°C). Since the isocyanate in the crosslinker component is considered unsustainable, there is a need to avoid this. However, currently available filling compounds without a crosslinker component are not suitable for use in vehicle interiors due to their lack of sufficient temperature stability; at temperatures above approximately 45°C, the conventional filling compound becomes sticky. The use of a reactive hot melt adhesive also does not provide a solution: Existing processes based on reactive hot melts require a processing temperature of 140°C ±20°C. However, such high temperatures can undesirably stress, damage, and / or discolor the decorative layer, especially its visible side.Furthermore, processing hot melt is particularly energy-intensive. Description of the invention

[0006] The object of the present invention is to provide a solution which enables the illumination of a translucent or opaque decorative layer of an interior surface for a vehicle while at the same time ensuring a high-quality surface finish of the interior surface.

[0007] This problem is solved by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the subclaims, the description, and the figures. Features, advantages, and possible embodiments presented in the description for one of the subject matter of the independent claims are to be regarded, across categories and embodiments, at least analogously as features, advantages, and possible embodiments of the respective subject matter of the other independent claims, as well as any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the subclaims.

[0008] According to the invention, a method for producing a translucent interior surface for a vehicle is proposed. The invention also includes the translucent interior surface produced by the method.

[0009] In the method for producing the translucent interior surface for the vehicle, a perforated decorative layer with one or a plurality of openings is first provided. The openings extend between a rear side and a visible side of the decorative layer, with each opening opening at the visible side and / or the rear side. This means that each opening can penetrate the decorative layer completely or partially. Thus, each opening can be a blind hole or a through-opening. The openings can have any shape or geometry. For example, the openings can be designed according to ellipses, circles, polygons, text characters, images, symbols, etc. Furthermore, each opening can be designed, for example, as a line, meandering line, line with different widths, broken line, etc. Intersecting lines, etc. are also conceivable.An inner wall of the respective opening can be arranged straight or obliquely relative to the visible side of the decorative layer. Furthermore, the openings can be positioned in any regular or irregular arrangement relative to one another. Furthermore, the respective opening can have a three-dimensional insert, for example, an electronic component, a gemstone, an emblem, a housing with or without an integrated light guide and / or with or without an integrated light source, or the like.

[0010] The decorative layer can be made of textile, leather, polyvinyl chloride or PVC artificial leather, polyurethane or PU artificial leather, thermoplastic elastomer or TPE artificial leather, a microfiber fabric such as Alcantara or Dinamica, a bio-based leather substitute, paper, etc. In these cases, the respective material can be selected so that the decorative layer is not at all or only poorly translucent. However, a highly translucent decorative layer is not excluded. A less flexible decorative layer is also conceivable, for example one made of stone, wood, plastic, metal, ceramic, glass, etc. At least through the perforation, which then has through-openings, light can penetrate the decorative layer when it is illuminated or transilluminated from behind.The back of the decorative layer can be coated with a polymer, an adhesive, for example a transparent hot melt or a dispersion, before the use of a non-reactive filling compound, which is explained in more detail below.

[0011] The visible side of the decorative layer is covered with a cover layer, covering the openings. The cover layer can be arranged, with its side facing away from the visible side of the decorative layer, on a rigid or stable base, for example. This base can be a plastic base reinforced with glass fibers, for example. In general, the cover layer can be arranged, for example, on a carrier base, after which the perforated decorative layer is placed or pressed with its visible side onto the cover layer in order to cover the visible side of the decorative layer and cover the openings. If the openings are designed as through-openings, the cover layer closes the openings in the decorative layer, so that the openings form blind openings and no longer through-openings as long as the cover layer is applied.Covering the visible side with the cover layer means both that the cover layer is applied directly to the visible side of the decorative layer and indirectly to it. The latter is explained by way of example in the following paragraph. For example, if there is a contoured, embossed surface on the visible side of the decorative layer, the openings can be located in the depressed or raised area. Accordingly, the cover layer / cover plate will then have depressions and / or raised areas for its sealing function.

[0012] Before the decorative layer is perforated, a protective layer may have been applied to the visible side, in which case the decorative layer and the protective layer can be perforated together. The perforation can be carried out via the exposed back of the decorative layer or via the visible side covered with the protective layer. If through-openings are created, the holes created in the decorative layer during perforation and the holes created in the protective layer during the same perforation are aligned. The covering of the visible side with the cover layer is then done indirectly and not directly. This is because the cover layer lies directly against the protective layer, whereby the openings in the decorative layer on its visible side are also covered. The visible-side protective layer is preferably removed from the decorative layer before the cover layer is applied to the decorative layer.If the adhesion between the cover layer and the visible side of the decorative layer, i.e., its decorative surface, is insufficient, the use of a protective layer can be advantageous. The material of the protective layer and the cover layer can be selected so that they adhere well to each other. This means, in particular, that the protective layer and the cover layer adhere better to each other than the cover layer would adhere directly to the visible side of the decorative layer.

[0013] The process further provides a translucent, non-reactive filling compound that cures reversibly or irreversibly. The non-reactive filling compound is, in particular, a non-reactive adhesive, for example, a non-reactive dispersion adhesive. A non-reactive hot melt adhesive, processed, for example, using a low-pressure injection molding process, is equally conceivable. The non-reactive adhesive is, for example, a polymer with adhesive properties. Of particular note is the fact that the filling compound used here does not contain a crosslinking component and is therefore isocyanate-free. In this case, the filling compound is a single-component compound that is free of isocyanate.In its processable state, the filling mass is provided as an aqueous or pasty mass in which water and solid of the filling mass are present, for example, in a ratio of 50:50, preferably 40:60.

[0014] The non-reactive filling compound, which can also be described as inert or unreactive, is advantageous in that it provides a virtually infinite processing time window. In other words, the non-reactive filling compound does not require a so-called pot life, as mixing with another substance for processing the filling compound is unnecessary. Process quality fluctuations are thus also avoided, as mixing errors are excluded. If additives are intended, such as coloring or tinting agents, powders, small structural elements (particularly translucent, refractive, or opaque), such as spheres or diamonds, etc., these or their materials are selected so that they do not react chemically with the filling compound. Furthermore, the filling compound is designed so that it remains dimensionally and structurally stable for several weeks after processing at temperatures up to 130 °C, preferably up to 150 °C and above.This effect is further enhanced when the filling compound is processed with a water-to-solids ratio of 40:60 or higher. Therefore, the non-reactive dispersion adhesive is preferably used as the non-reactive filling compound, as it can be processed at temperatures from 6°C to 40°C, particularly from 10°C to 25°C. Further advantages of the filling compound are its particularly low susceptibility to yellowing due to thermal oxidation, its solvent-free nature (as it is water-based), and its ability to be processed at low temperatures—especially at room temperature. This prevents damage to the decorative layer, and prevents discoloration due to exudation of the transparent filling compound. Furthermore, the filling compound is particularly resistant to UV light.In principle, any non-reactive filling compound can be used, provided they are compatible with the decorative layer used, do not attack it, and exhibit the required or specified light transmittance. Any fluid media suitable for the described filling process, based on one-component systems, two-component systems, and the like, can be used as the filling compound, provided they are sufficiently transparent, UV-stable, non-reactive, viscoelastic, flexible, rapidly non-blocking, emission-free, adhere well, and compatible with the decorative surface in question. Furthermore, the filling compound used preferably exhibits no significant stringing or gas formation.

[0015] In this process, the non-reactive or inert filling compound is applied to the back of the decorative layer covered by the cover layer before the filling compound has hardened. The openings are then completely or partially filled with the filling compound by applying pressure to the filling compound; for example, it is conceivable that only the inner walls of the openings are coated with the filling compound. The filling compound then hardens into a rigid or flexible filling body that sits in the respective opening at least in a form-fitting manner, preferably in a material-fitting manner due to the adhesive bond between the filling compound and the inner wall of the corresponding opening.Once the filler compound has hardened, at least to the extent that the cover layer can be removed without damaging it, the cover layer is removed from the visible side of the decorative layer, namely after the openings have been filled with the filler compound and the filler compound has hardened, at least in the area facing the cover layer. The filler compound has hardened so much in this area that it remains in the openings even after the cover layer has been removed. The filler compound or adhesive therefore provides greater adhesion to the opening wall than to the cover layer.

[0016] Using this process, it is possible to fill the perforated decorative layer completely and evenly with the non-reactive filling compound. If necessary for a specific application, a non-uniform or homogeneous filling can also be carried out. The perforated decorative layer is therefore sealed using the filling compound. It is therefore possible to fill the openings in the decorative layer completely and evenly with the filling compound. Light generated from the back of the translucent interior surface can escape with minimal loss onto the visible side of the decorative layer and thus be projected. In particular, using this process it is possible for the visible side of the decorative layer to form a flush surface together with the filling compound after the filling process. This can create a particularly high haptic value for the translucent interior surface.Covering the visible side of the decorative layer with the cover layer ensures that the visible side of the decorative layer remains free of filling compound during the filling process. This allows a type of edge-accurate sealing of the perforated decorative layer to be achieved using the filling compound. By filling the openings in the perforated decorative layer with the filling compound, the filling compound prevents the decorative layer with the openings from becoming clogged with dirt or similar. This also significantly simplifies the maintenance of the interior surface, as the visible side and the filling compound form a seamless, gap-free surface in the area of ​​the openings. This allows a wide variety of different designs to be created particularly efficiently, in particular seamless light guides (so-called seamless light guides).It is possible to illuminate a non-transparent or barely translucent decorative layer of a vehicle interior surface while simultaneously achieving a high-quality surface finish for the decorative layer. The translucent interior surface produced in this way can be used, for example, for extensive ambient lighting, functional integration through illuminated displays, displays behind the decorative layer, for functional lighting, for displaying symbols or emblems with optional switches, or the like. In addition, loudspeaker grilles can be integrated into the decorative layer, or ventilation openings for air conditioning can be provided using the method according to the invention. Above all, the method according to the invention makes it possible to ensure that the filling compound does not protrude beyond the visible side of the decorative layer.This allows for a high-quality and particularly smooth feel on the interior surface. The method according to the invention makes it possible to process decorative layers of varying thicknesses made from a wide variety of materials and with a wide variety of geometries or shapes with regard to the openings. Furthermore, the method according to the invention makes it particularly easy to automate the process.

[0017] To ensure that the filling compound is flowable, it can be melted before being introduced or applied and then injected from the back of the decorative layer using a pressure-applying process to ensure that the openings are filled evenly. A key factor in achieving a homogeneous appearance of the translucent interior surface is the use of a suitable application technique to create a bubble-free film and then, likewise, to inject this bubble-free film into the perforation, i.e., the openings, using the pressure-applying process. The application of the filling compound and the filling of the openings by applying pressure or using the pressure-applying process can be carried out in a single step. Optionally, the filled decorative layer can be fed through a flatbed laminating machine, which smooths out any uneven filling application on the back by lightly pressing it over.

[0018] According to a possible further development, the filling compound, in particular the non-reactive dispersion adhesive, is designed such that in its processable state, i.e. as the aqueous or pasty compound, it has a dynamic viscosity of 1000 mPa s to 8000 mPa s (inclusive). Preferably, it has a dynamic viscosity of 2000 mPa s to 3000 mPa s (inclusive). This dynamic viscosity contributes to particularly easy processability of the filling compound. The filling compound is therefore given the aforementioned dynamic viscosity before it hardens, in particular before it is introduced into the openings, for example by the filling compound already having a corresponding composition in the as-delivered state and / or by it being treated during the process, for example by heating it, so that its dynamic viscosity lies within the aforementioned value range, at least during introduction into the openings.

[0019] Another possible embodiment provides for applying enough filling compound to the back side so that, after filling the openings, a layer of filling compound is formed on the back side, which bonds the filling compounds introduced into the openings together. The bond can be chemical. This bonds the filling compounds together in the back side of the decorative layer. This results in particularly stable filling of the openings, and it also results in particularly good translucency properties, especially if the layer of filling compound on the back side is particularly uniform.

[0020] According to a further possible embodiment, the layer made of filling compound is used as an adhesive for a further layer, in particular a spacer fabric, a carrier, or a functional layer. The filling compound can therefore also be used as an adhesive in a subsequent step after the actual filling of the openings, for example by positional joining, in order to bond a spacer fabric, a carrier, functional layers such as light guides, or functional layers for electrical functions or the like to the back of the decorative layer using the not yet solidified filling compound. Preferably, the filling compound and a further layer are bonded using an adhesive (dispersion or hotmelt). This adhesive is, in particular, light-transparent. This makes it possible to eliminate separate process steps, including, for example, expensive special workstations.The manufacturing process of the translucent interior surface with layers arranged behind it can be accelerated.

[0021] Another possible embodiment provides for the respective material properties to be selected such that the filling compound adheres more strongly to the decorative layer than to the cover layer. This allows the cover layer to be relatively easily peeled off the decorative layer after the filling process or removed without dissolving the introduced filling compound from the openings in the decorative layer.

[0022] According to another possible embodiment, a silicone mat or a decorative adhesive plate is used as the cover layer. The silicone mat or the decorative adhesive plate is used in particular multiple times, whereby, with a suitable choice of filling material, little or no wear occurs on the silicone mat. Furthermore, the silicone mat makes it possible to reliably seal the openings during the filling process in a particularly reliable manner. The material of the silicone mat has, in particular, a Shore hardness of less than 40, preferably less than 5, particularly preferably less than 1.

[0023] According to another possible embodiment, after the cover layer has been removed, the respective surfaces of the filling compound adjacent to the visible side are at least partially coated or printed with a colored material. This can, for example, create an invisible daytime design on the interior surface. Due to the colored material, the interior surface appears uniform when the backlighting is deactivated, and only when the backlighting is activated does a specific light design become visible through the filled openings. Furthermore, a targeted contrast can be created between the filling compound and the decorative layer, which is visible on the interior surface even when the backlighting is deactivated. From the visible side, the finished interior surface can be coated, depending on the desired result, with an appropriate coloring system with high decorative adhesion, such as a polyurethane varnish.The optical properties of the translucent interior surface and especially of the filling material can thus be adjusted very specifically.

[0024] To create a predetermined surface structure, and thus also a corresponding optical property, according to a further possible embodiment, the cover layer is provided with a surface structure on the respective surfaces of the filling material adjacent to the visible side. In this case, the cover layer can determine the surface structure of the filling material and thus also specify the optical properties of the filling material. The surface structure previously created on the cover layer is thus evident on the respective surfaces of the filling material adjacent to the visible side. In this way, for example, the scattering behavior and the corresponding light transmission through the filling material can be influenced. It is also possible, for example, to achieve a desired transparency or a desired degree of transparency by suitable mixtures of materials forming the filling material.

[0025] Furthermore, to create a predetermined surface structure on the respective surfaces of the filling compound adjacent to the visible side, it is possible to perform a chemical surface treatment with a fluid and / or irradiation with light of a predetermined wavelength and / or heat irradiation of a predetermined wavelength. This also makes it possible to adjust the desired optical and / or haptic properties of the filling compound.

[0026] In another possible embodiment, after the cover layer has been removed, the respective surfaces of the filling compound adjacent to the visible side are structured with a tool. This makes it possible, in particular, to achieve a specific degree of gloss during filling. For example, it is possible to structure the surface of the filling in the area of ​​the visible side using a cold steel tool. This can, for example, make the filling compound appear just as matte as the decorative layer. Furthermore, the tool can be an embossing die or a laser.

[0027] According to a further possible embodiment of the invention, after the openings have been covered with the cover layer and before the openings are filled, a coloring material is introduced into the openings, which combines with the filling compound when the openings are filled. For example, a colored film can be introduced into the perforation of the decorative layer. This introduction of the film takes place after the decorative layer has been provided with the protective cover layer on its visible side. The film combines with the filling compound during filling and can therefore specifically influence the optical properties of the filling compound. Furthermore, it is conceivable to influence the surface structure and the optical properties after the filling process by means of an etching process or by dissolving particles from the filling compound.Furthermore, tiny particles, such as powder, can be applied to the filling material from the visible side, penetrating it. This could, for example, create a kind of scattering layer in the area of ​​the filling material. As a result, a particularly homogeneous light or illumination is achieved. Due to the scattering effects, the light is also emitted in such a way that it is visible over a very wide angular range, which would not be possible without this scattering effect.

[0028] In a possible further development, a negative pressure is applied in the area of ​​the back of the decorative layer during filling of the covered openings in order to suck any air bubbles contained in these openings towards the back, essentially eliminating the air bubbles from the filling material. It is also conceivable to carry out the filling in a hermetically sealed space in which negative pressure prevails, in particular a technical vacuum. This allows air trapped in the filling material to escape during the filling process, effectively preventing the formation of noticeable cavities or air pockets. By applying the negative pressure in the area of ​​the back of the decorative layer, the cover layer can also be sucked towards the visible side or ventilated, so that it seals the openings particularly well.

[0029] According to a further possible embodiment, the covering layer is selected such that air can pass through it, but the filling compound cannot. During the filling of the covered openings, a negative pressure is exerted on the covering layer in order to suck out any air, in particular air bubbles, contained in the covered openings through the covering layer. In this way, the filling compound can be vented via gas diffusion, as the air diffuses through the covering layer. This is also a good way to ensure that no air pockets form in the filling compound. Otherwise, it is also possible to create a relatively hot temperature or environment during the process to ensure a sufficiently low viscosity of the filling compound during the filling process, as a result of which any existing air pockets can escape.

[0030] A further possible embodiment of the invention provides that the filling compound is applied to the back of the decorative layer by means of an application roller rotating in the same direction or counter-rotation with the decorative layer and pressed into the covered openings. This makes it particularly simple and reliable to produce the translucent interior surface as a virtually continuous material, which can be finished after the filling process. The rotating application roller can have a grooved surface so that it can take along and apply sufficient filling compound. For example, a container open at the bottom can be arranged above the application roller, in which the filling compound is provided. This then reaches the rotating application roller, which, through its rotation and its grooved surface, conveys the filling compound towards the back of the decorative layer and thus towards the openings.By applying appropriate pressure using the application roller (via direct roller contact with the decorative layer or via the roller and intermediate filling compound with the decorative layer) in the area of ​​the back of the decorative layer, it can be ensured that the filling compound is pressed into the openings. The cover layer together with the decorative layer arranged on it can be conveyed underneath the application roller, for example, using a suitable conveyor device, in particular a conveyor roller or a linear conveyor. The rotating application roller is therefore not moved in a translational manner, whereby the composite formed from the cover layer and the decorative layer arranged on it is conveyed underneath the rotating application roller by said conveyor device. It is also possible to apply the filling compound by spraying it onto the back of the decorative layer and to fill the openings by applying pressure to the filling compound.

[0031] An alternative possible embodiment provides for the cover layer to be placed in an open mold, then the decorative layer to be placed on the cover layer, then the mold to be closed, and then the filling compound to be injected into the closed mold through at least one opening directed toward the back of the decorative layer. In other words, the filling compound is applied to the back of the decorative layer in a type of injection molding process, and under correspondingly high pressure, the openings covered by the cover layer are filled with the filling compound on the back. This procedure is very well suited for high volumes, ensuring the good reproducibility required, particularly for mass production.

[0032] According to a further alternative, the non-reactive filling material is provided in the form of a single- or multi-layer film or a single- or multi-layer mesh, which is placed on the back of the decorative layer and thus over the openings, and the film or mesh is pressed into the openings. If the film or mesh is two or more layers, one of the layers can be a different color than another layer and / or be transparent. In particular, sensitive press plates, roller presses, rollers, etc. can be used for the pressing process. Drying or curing can take place - as is generally possible with this process - in a heating oven, using tempered plates, using infrared radiators, by radiant heat, or by air drying. Any combination of drying methods is, of course, conceivable.By providing the filling material as a net or film, it can be processed and stored particularly easily. It also allows for "dry" processing of the filling material.

[0033] In this context, a possible further development provides for the filling compound in the form of a film or mesh to be preheated before being pressed in. This ensures that the filling compound film or mesh adheres particularly closely to the decorative layer to be filled, thereby ensuring a favorable quality of the filled decorative layer. To preheat the filling compound film or mesh, for example, the means that can also be used to dry the filling compound can be used. For pressing in, the filling compound or mesh or film is selected or pretreated in such a way that it has a dynamic viscosity of 6000 mPa s to 7000 mPa s. The film can be pressed in using a roller that presses from the film side towards the decorative layer. Alternatively or additionally, another roller can be used that presses from the visible side towards the decorative layer.

[0034] Furthermore, a possible refinement provides for two or more films or nets of filling material to be applied in layers to the back, with the films or nets of filling material differing in terms of transparency and / or color. This further increases design flexibility.

[0035] According to a further alternative embodiment, the non-reactive filling compound is applied and / or introduced onto and / or into the back of the decorative layer by means of one of the following application processes: - doctor blade, - Spraying, - Pouring, - Brush on, - rolling, - Stamping, - generative application, especially 3D printing, - Pressing, - Spraying, - rolling, - squeegeeing, - Pouring, - Impressions.

[0036] The alternatives described above each apply to a single layer of filler material. If two or more layers of filler material are planned, these alternatives can be combined.

[0037] Further advantages, features, and details of the invention can be derived from the following description of possible embodiments and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures alone, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention. Short character description

[0038] The drawing shows: Fig. 1 is a schematic side sectional view of a partially illustrated perforated decorative layer with a plurality of openings extending from a rear side of the decorative layer to a visible side of the decorative layer, wherein the visible side and thus also the openings are covered by a cover layer, Fig. 2 a schematic representation of an application and filling process of filling compound by means of an application roller in the area of ​​the back of the decorative layer, Fig. 3 a schematic side sectional view of the decorative layer after the openings have been filled with the filling compound and Fig. 4 a schematic representation of an application and filling process of filling material, wherein the filling material is provided as a film or as a net.

[0039] Identical and functionally identical elements are provided with the same reference symbols in the figures.

[0040] A perforated decorative layer 10 is shown in a schematic side sectional view in Fig. 1 is partially shown. The decorative layer 10 has an opening (12), in this case a plurality of openings 12, which extend from a rear side 14 of the decorative layer 10 to a visible side 16 of the decorative layer 10. The illustrated conicity of the openings (12) can also be opposite. The decorative layer 10 is a layer that is slightly or not at all translucent, for example made of leather, artificial leather, a plastic or the like. It is also possible for the decorative layer 10 to comprise a rigid material such as wood or stone. The visible side 16 is the side of the decorative layer 10 which, in a correct installation position, faces the vehicle occupants and thus a passenger compartment. The perforation orThe openings 12 serve to backlight the decorative layer 10, which is not translucent or only poorly translucent, and thus to illuminate it, so that ambient lighting or, more generally, light patterns can be created on the visible side 16 for vehicle occupants.

[0041] A method for producing a translucent interior surface for a vehicle, which comprises the decorative layer 10, is explained in more detail below. First, the perforated decorative layer 10 is provided, which has the aforementioned openings 12. The openings 12 alternate with respective areas 18 of the decorative layer 10 that are not perforated. The visible side 16 of the decorative layer 10 is covered with a cover layer 20, wherein the openings 12 are also covered by the cover layer 20 and thus essentially form only blind holes.

[0042] The cover layer 20 can, for example, be a silicone mat, which is placed or positioned on a base not shown here. The perforated decorative layer 10 can then be placed on the cover layer 20. For example, it can be a glass-fiber-reinforced plastic base, which can serve as a type of carrier base for the cover layer 20. The advantage of this glass-fiber-reinforced base is, among other things, that it is light yet stable. In addition, the silicone mat serving as the cover layer 20 adheres relatively well to the base not shown here, which facilitates later removal of the cover layer 20 from the decorative layer 10.

[0043] In Fig. 2, the decorative layer 10 and the cover layer 20 are shown in a schematic side sectional view, while a molten filling compound 22 adhering to the latter is applied to the perforated decorative layer 10 in the region of the rear side 14 by means of an applicator roller 19. For example, a container (not shown here) with an outflow opening in the lower region can be arranged above the applicator roller 19, by means of which container the molten and translucent filling compound 22 is provided. The applicator roller 19 rotates in a direction of rotation 24 and thus continuously conveys the molten and translucent filling compound 22 towards the rear side 14 of the perforated decorative layer 10. The filling compound 22 is a non-reactive filling compound 22. The filling compound 22 can be a non-reactive hot melt adhesive. However, a water-based dispersion adhesive is preferred as the filling compound 22.

[0044] The molten filling compound 22 is applied in the area of ​​the rear side 14 of the decorative layer 10 covered by the covering layer 20 on its visible side 16, wherein the openings 12 are filled with the filling compound 22 by exerting pressure by means of the application roller 19, which then hardens.

[0045] The cover layer 20, together with the decorative layer 10 arranged thereon, can be conveyed in a conveying direction 26 beneath the application roller 19, for example, by means of a conveying device (not shown here). For this purpose, the conveying device can, for example, comprise a conveying roller (not shown here) that rotates in the opposite direction to the application roller 19, as a result of which the decorative layer 10, together with the cover layer 20 attached thereto, is conveyed beneath the application roller 19 in the conveying direction 26.

[0046] This conveyor roller can, for example, rest on the underside of the said base on which the cover layer 20 is arranged. It is also possible, for example, for the conveyor device to have a linear conveyor (not shown here), for example in the form of a conveyor belt or the like, to convey the cover layer 20, together with the decorative layer 10 arranged thereon, to the application roller 19 and underneath it. In this case, the said base can, for example, be arranged on the linear conveyor.

[0047] Contrary to the representation in Fig. 2, it is also possible, for example, for the cover layer 20 to be arranged in an open mold. The decorative layer 10 is then arranged on the cover layer 20, and the mold is subsequently closed. The molten filling compound 22 is then injected into the mold through at least one opening directed toward the back side 14 of the decorative layer 10.

[0048] In Fig. 3 shows a translucent interior surface 28 comprising the perforated decorative layer 10 and the filling compound 22 that fills the previously existing openings 12. The cover layer 20 is removed from the visible side 16 of the decorative layer 10 after completion of the translucent interior surface 28, specifically after the openings 12 have been filled with the filling compound 22. Sufficient melted filling compound 22 was applied to the rear side 14 that, after the openings 12 have been filled, a layer of filling compound 22 was formed on the rear side 14 (not identified in more detail here), which chemically bonds the filling compound 22 introduced into the openings 12.

[0049] The layer of filling compound 22 can also serve as an adhesive for another layer not shown here, such as a spacer fabric, a carrier, or a functional layer. The respective material properties are selected such that the filling compound 22 adheres more strongly to the decorative layer 10 than to the cover layer 20. This facilitates the peeling or removal of the cover layer 20 without the cover layer 20 partially tearing out the introduced filling compound 22 in the area of ​​the previously existing openings 12.

[0050] After removing the cover layer 20, the respective surfaces of the filling compound 22 adjacent to the visible side 16 can also be coated, for example, with a colored material to create desired optical properties. It is also possible to provide the cover layer 20 with a surface structuring on its surface facing the filling compound 22 to create a predetermined surface structure on the respective surfaces of the filling compound 22 adjacent to the visible side 16. This surface structuring then, in turn, affects the surface structure or surface structuring of the filling compound 22. Certain optical properties of the filling compound 22 can thus also be adjusted.

[0051] Furthermore, after removing the cover layer 20, it is also possible to structure the respective surfaces of the filling compound 22 adjacent to the visible side 16 with a cold tool. This also makes it possible to produce a desired surface structure on the filling compound 22 with the associated optical properties.

[0052] Furthermore, it is also possible that after covering the openings 12 with the covering layer 20 and before filling the openings 12, a colored material is introduced into the openings 12, which combines with the filling compound 22 when the openings 12 are filled. This makes it possible to achieve a corresponding coloring of the filling compound 22. This can, for example, also be done differently for the different openings 12. For example, it is possible to select the coloring such that the coloring of the filling compound 22 at least substantially corresponds to the color of the decorative layer 10. However, it is equally possible to select a contrasting color or a contrast-creating coloring.

[0053] When filling the openings 12, it is essential that the opening 12 is filled with the filling compound 22 without any bubbles, i.e. that no air pockets remain. To ensure this, it can be provided, for example, that a negative pressure is exerted in the area of ​​the rear side 14 of the decorative layer 10 in order to suck any air contained in the covered openings 12 towards the rear side 14 during the filling of the covered openings 12. The cover layer 20 can also be selected such that air can pass through it, but the molten filling compound 22 cannot, wherein a negative pressure is exerted on the cover layer 20 during the filling of the covered openings 12 in order to suck any air contained in the covered through-holes 12 through the cover layer 20 during the filling of the covered through-holes 12.The ambient temperature can also be selected so that the translucent filling mass 22 has a sufficiently thin liquid for long enough for air to escape upwards from the filling mass 22.

[0054] By means of the explained method, it is possible to provide a translucent interior surface 28, which enables the illumination of a non-translucent or barely translucent decorative layer 10. At the same time, a high-quality surface finish of the translucent or backlit interior surface 28 can be ensured. By means of the described method, it is possible to realize a flush seal between the filling compound 22 and the visible side 16 of the decorative layer 10, if this should be desired. Furthermore, it is possible, in accordance with the above explanations, to adjust the optical properties of the filling compound 22 as desired. By filling the openings 12 with the translucent filling compound 22, on the one hand, dirt can be prevented from penetrating the openings 12. On the other hand, by appropriate treatment orBy selecting the right material for the filling compound 22, a larger viewing angle can be realized, allowing the transillumination or backlighting of the interior surface 28 to be visible. This can also be achieved with a very high surface quality of the translucent interior surface 28.

[0055] Depending on the filling compound 22, it may not necessarily need to be melted before application. It is essential that the filling compound 22 is non-reactive and cures reversibly or irreversibly. Furthermore, the filling compound 22 should exhibit sufficiently good flowability during application and introduction into the openings 12. The filling compound may have a dynamic viscosity of 1000 mPa s to 8000 mPa s, particularly 2000 mPa s to 3000 mPa s, particularly before curing and during introduction into the openings.

[0056] Fig.Figure 4 shows a schematic representation of an application and filling process for filling compound 22, wherein the filling compound 22 is provided as a film or mesh 30. The film 30 or mesh 30 is placed on the back 14 of the decorative layer 10 and consequently over the openings 12, and the film 30 or mesh 30 is then pressed into the openings 12. For this purpose, sensitive press plates, roller presses, rollers, etc. are used in particular. Drying or curing can take place—as is generally possible with the process—in a heating oven, using tempered plates, with the aid of infrared radiators, by radiant heat, or by air drying. Any combination of drying methods is, of course, conceivable.

[0057] In this case, the filling compound 22 in the form of the film 30 or the mesh 30 is preheated before pressing. This ensures that the filling compound film 30 or the filling compound mesh 30 adheres particularly closely to the decorative layer 10 to be filled. For preheating the filling compound film 30 or the filling compound mesh 30, for example, the means that can also be used to dry the filling compound 22 are suitable. For pressing, the filling compound 22 or the mesh 30 or the film 30 is selected or pretreated in particular such that it has a dynamic viscosity of 6000 mPa s to 7000 mPa s.

[0058] Two or more films 30 or nets 30 made of filling material 22 can be applied in layers to the back 14, which differ in terms of transparency and / or color.

[0059] Alternatively, the non-reactive filling compound is applied and / or introduced onto and / or into the back of the decorative layer using one of the following application processes: - doctor blade, - Spraying, - Pouring, - Brush on, - rolling, - Stamping, - generative application, especially 3D printing, - Pressing, - Spraying, - rolling, - squeegeeing, - Pouring, - Impressions. LIST OF REFERENCE SYMBOLS 10 perforated decorative layer 12 through holes in the decorative layer 14 Back of the decorative layer 16 Visible side of the decorative layer 18 areas between the through openings of the decorative layer 19 Application roller 20 Cover layer 22 Filling mass 24 Direction of rotation 26 direction 28 translucent interior surfaces 30 foil or net

Claims

[1] Method for producing a translucent interior surface (28) for a vehicle, comprising the steps: - Providing a perforated decorative layer (10) with one opening (12) or a plurality of openings (12) which extend between a rear side (14) of the decorative layer (10) and a visible side (16) of the decorative layer (10) and open at one or both of the sides (14, 16), - covering the visible side (16) of the decorative layer (10) with a covering layer (20) covering the through openings, - providing a translucent non-reactive filling compound (22) which hardens reversibly or irreversibly, - applying the provided filling compound (22) to the back (14) of the decorative layer (10) covered by the covering layer (20) before the latter has hardened, wherein the openings (12) are filled with the filling compound (22) by exerting pressure on the latter, - removing the cover layer (20) from the visible side (16) of the decorative layer (10) after the openings (12) have been filled with the filling compound (22) and the filling compound (22) has hardened at least in its region facing the cover layer (20) or has hardened at least to such an extent that the cover layer (20) can be removed. [2] Method according to claim 1, characterized by that so much non-reactive filling compound (22) is applied to the back side (14) that after filling the openings (12) on the back side (14) a layer of the filling compound (22) is formed which connects the filling compound (22) introduced into the openings (12) to one another. [3] Method according to claim 1 or 2, characterized by that the layer of the non-reactive filling compound (22) is used as an adhesive for a further layer, in particular a spacer fabric, a carrier or a functional layer. [4] Method according to one of the preceding claims, characterized by that a non-reactive hot melt adhesive is used as the filling compound (22). [5] Method according to one of the preceding claims, characterized by that the respective material properties are selected such that the non-reactive filling compound (22) adheres more strongly to the decorative layer (10) than to the covering layer (20). [6] Method according to one of the preceding claims, characterized by that a silicone mat or a decorative adhesive plate is used as the covering layer (20). [7] Method according to one of the preceding claims, characterized by that after removal of the covering layer (20), respective surfaces of the non-reactive filling compound (22) adjacent to the visible side (16) are at least partially coated or printed with a colored material. [8] Method according to one of the preceding claims, characterized byin that, in order to produce a predetermined surface structure on respective surfaces of the non-reactive filling compound (22) adjacent to the visible side (16), the covering layer (20) is provided with a surface structuring. [9] Method according to one of the preceding claims, characterized by in that, in order to produce a predetermined surface structure on respective surfaces of the non-reactive filling compound (22) adjacent to the visible side (16), a chemical surface treatment with a fluid and / or irradiation with light of a predetermined wavelength and / or heat irradiation of a predetermined wavelength is carried out. [10] Method according to one of the preceding claims, characterized by that after removal of the covering layer (20), respective surfaces of the non-reactive filling compound (22) adjacent to the visible side (16) are structured with a tool. [11] Method according to one of the preceding claims, characterized bythat after covering the through openings with the covering layer (20) and before filling the openings (12), a coloring material is introduced into the openings (12), which combines with the non-reactive filling mass (22) when filling the openings (12). [12] Method according to one of the preceding claims, characterized by that during the filling of the covered openings (12) in the region of the back (14) of the decorative layer (10) a negative pressure is exerted in order to suck out air bubbles located in the covered openings (12) in the direction of the back (14) during the filling of the covered openings (12). [13] Method according to one of the preceding claims, characterized bythat the cover layer (20) is selected such that air can pass through it, but the filling compound (22) cannot, wherein during the filling of the covered openings (12) a negative pressure is exerted on the cover layer (20) in order to suck out air present in the covered openings (12) through the cover layer (20) during the filling of the covered openings (12). [14] Method according to one of the preceding claims, characterized by that the non-reactive filling compound (22) is applied to the back side (14) of the decorative layer (10) by means of an application roller (19) rotating in the same direction or in the opposite direction with respect to the decorative layer (10) and is pressed into the covered openings (12). [15] Method according to one of claims 1 to 13, characterized bythat the cover layer (20) is arranged in an open tool, then the decorative layer (10) is arranged on the cover layer (20), then the tool is closed and then the non-reactive filling compound (22) is injected into the tool through at least one opening directed towards the back (14) of the decorative layer (10). [16] Method according to one of claims 1 to 13, characterized by that the non-reactive filling mass (22) is provided in the form of a single- or multi-layer film or a single- or multi-layer net, and is placed on the back (14) of the decorative layer (10) and consequently over the openings (12), and the film or net is pressed into the openings (12). [17] Method according to claim 16, characterized by that the filling mass (22) in the form of the film or net is preheated before pressing. [18] Method according to claim 16 or 17, characterized bythat two or more films or nets of filling material (22) are applied to the back (14) in layers, wherein the films or nets of filling material (22) differ in terms of transparency and / or color. [19] Method according to one of claims 1 to 13, characterized by that the non-reactive filling compound (22) is applied and / or introduced onto and / or into the back (14) of the decorative layer (10) by means of one of the following application processes: - doctor blade, - Spraying, - Pouring, - Brush on, - rolling, - Stamping, - generative application, especially 3D printing, - Pressing, - Spraying, - rolling, - squeegeeing, - Pouring, - Impressions. [20] Translucent interior surface (28) for a vehicle, in particular for a passenger car and / or truck, which is produced by means of a method according to one of the preceding claims.

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