FIXATION OF COLOR SOLUTIONS IN CERAMIC MULTI-COLOR INKJET 3D PRINTING

Description

[0001] The present invention relates to a method for producing a dental restoration by jet pressure and a manufacturing device for producing a dental restoration by jet pressure.

[0002] In this context, EP 2 529 694 A1 is mentioned, which discloses such a process and manufacturing equipment.

[0003] When manually staining zirconia ceramic restorations, infiltration solutions of nitrate salts are used for individual coloring. These are applied to the surface of the restoration, for example with a brush, and then diffuse into the porous ceramic. This application requires a high level of experience on the part of the dental technician.

[0004] This coloring process for zirconia white casts can be automated by using a computer-controlled airbrush system to infiltrate the restoration. In additive manufacturing processes, differently colored, solvent-based ceramic slips can be selectively applied using inkjet printing. The processing of highly filled ceramic slips places high demands on the printheads used, in terms of particle size, fill level, and therefore viscosity and abrasion. Jet printing of aqueous slips offers an alternative to solvent-based slips. In this process, the jet-printed material layer is dried without cracking.

[0005] However, during a manual infiltration process, the salt solutions diffuse uncontrollably into the zirconia blank. With layered material application combined with layered, selective staining of the previously applied ceramic layer, the previously deposited nitrate salts are dissolved again in the underlying layers and diffuse uncontrollably further into the already fabricated ceramic body.

[0006] The technical object of the present invention is to prevent the uncontrolled diffusion or runoff of selectively applied nitrate salt solutions as dye solutions during a spatial layer build-up process.

[0007] This problem is solved by the articles according to the independent claims. Technically advantageous embodiments are the subject of the dependent claims, the description, and the drawings.

[0008] According to a first aspect, the technical task is solved by a process for manufacturing a dental restoration using jet printing, comprising the steps of jet printing one or more layers of the dental restoration using a ceramic slurry; jet printing a staining solution onto the one or more layers; and applying a fixative solution to fix the staining solution. This prevents the uncontrolled diffusion or runoff of selectively applied nitrate salt solutions as staining solutions during a layer-by-layer process. Controlled, selective staining of the 3D-printed green body using staining solutions is ensured during the additive manufacturing process. Selective slurry material application and selective staining are performed separately. The same or different printheads can be used for material application and staining.The fixative solution prevents, for example, the diffusion of the dye solution on the aqueous slurry used to produce a multicolor green body. This ensures, for instance, controlled and selective coloring of the 3D-printed ZrO2 green body using dye solutions during the additive manufacturing process.

[0009] In a technically advantageous embodiment of the method, the fixing solution is sprayed onto one or more layers. This achieves, for example, the technical advantage that the fixing solution can be applied quickly and over a large area.

[0010] In a further technically advantageous embodiment of the method, the fixing solution is jet-printed onto one or more layers using a printhead. This achieves, for example, the technical advantage that the fixing solution can be applied selectively and with pinpoint accuracy.

[0011] In another technically advantageous embodiment of the process, the one or more layers are dried before or after the jet printing of the dye solution. This achieves, for example, the technical advantage of reducing diffusion of the dye solution.

[0012] In another technically advantageous embodiment of the method, the one or more layers are dried before or after the application of the fixing solution. This also achieves the technical advantage, for example, of reducing diffusion of the dye solution.

[0013] In another technically advantageous embodiment of the method, the pH value of the fixing solution is greater than 7.

[0014] This achieves, for example, the technical advantage of effectively reducing the risk of the dye solution running.

[0015] In another technically advantageous embodiment of the method, the fixing solution is an ammonia-ammonium chloride solution. This achieves, for example, the technical advantage that the staining solutions are fixed locally.

[0016] In another technically advantageous embodiment of the method, the steps for fabricating the dental restoration are repeated. This achieves, for example, the technical advantage that the entire dental restoration can be built up and stained.

[0017] In another technically advantageous embodiment of the method, the dental restoration is sintered in a sintering furnace. This achieves, for example, the technical advantage of producing a dental restoration with high strength.

[0018] According to a second aspect, the technical problem is solved by a manufacturing device for producing a dental restoration by jet printing, comprising a first printhead for jet printing one or more layers of the dental restoration using a ceramic slurry; a second printhead for jet printing a staining solution onto the one or more layers; and an application device for applying a fixative solution to fix the staining solution. The manufacturing device achieves the same technical advantages as the method described in the first aspect.

[0019] In a technically advantageous embodiment of the manufacturing device, the application device is formed by a spray head for the surface application of the fixing solution.

[0020] This achieves, for example, the technical advantage that the fixing solution can be applied quickly and over a large area.

[0021] In another technically advantageous embodiment of the manufacturing device, the application device is formed by a printhead for the selective application of the fixing solution. This achieves, for example, the technical advantage that the fixing solution can be applied selectively and with pinpoint accuracy.

[0022] According to the invention, the manufacturing device comprises a receiving container with a fixing solution. The receiving container can be replaceable. This achieves, for example, the technical advantage that the fixing solution can be kept on hand and easily replaced.

[0023] In a further technically advantageous embodiment of the manufacturing device, the device comprises a drying unit for drying the applied materials, such as a slip layer, dye solution, or fixative solution. This achieves, for example, the technical advantage of reducing further diffusion.

[0024] In another technically advantageous embodiment of the manufacturing device, the drying device comprises a blower and / or an infrared emitter. This achieves, for example, the technical advantage that the layers can be dried quickly.

[0025] Exemplary embodiments of the invention are shown in the drawings and are described in more detail below.

[0026] They show: Fig. 1 shows different areas of an incisor; Fig. 2 shows a schematic representation of a dental restoration; Fig. 3 shows a schematic representation of a manufacturing device for producing a dental restoration; Fig. 4 shows a schematic view of a method for producing a dental restoration by jet pressure; Fig. 5 shows a schematic view of another method for producing a dental restoration by jet pressure; Fig. 6 shows a table with the compositions of different staining solutions; and Fig. 7 shows a block diagram of a method for producing a dental restoration.

[0027] Fig. 1 This shows a representation of different areas of tooth 105. Tooth 105 comprises an inner dentin core 101 and an outer enamel 103. The opaque dentin core 101 is responsible for the basic coloration of tooth 105. This core is visible through the enamel 103 of the incisal edge. The enamel 103 is naturally translucent. Translucency is the partial transmission of light by a substance. To make a dental restoration look as natural as possible, this structure of tooth 105 is also used in artificial dental restorations. For this purpose, materials with different optical properties are used in the fabrication of the dental restoration.

[0028] Fig. 2 Figure 1 shows a schematic representation of a dental restoration 100. The dental restoration 100 serves as a tooth replacement and is formed, for example, by a bridge, crown, full or partial denture. The dental restoration 100 is selectively built up layer by layer from, for example, 1-n different ceramic slips 109 using a jet printing process and receives its color after layer by layer selective staining with nitrate salts such as Fe₂O₃, Cr₂O₃, Mn₂O₃, Tb₂O₃, Pr₂O₃, Er₂O₃, Co₃O₄, NiO, TiO₂, CeO₂ and / or doping with z.B. Yttrium and a final sintering of the white material thus created for the dental restoration 100, a corresponding characterization in terms of color, translucency, opacity and mechanical properties.

[0029] The dental restoration 100 is built up in successive layers that are printed on top of each other. The ceramic powders of the slip 109 can already be provided in predetermined translucencies. By mixing these slips 109, the desired translucency of the dental restoration 100 is achieved in the respective spatial area.

[0030] After selective application of a layer of slurry 109 using the jet-jet printing method, this layer is dried crack-free by evaporating the water or solvent used as a binder. What remains is a porous white layer with a thickness of 1 µm to 50 µm and a density of at least 2.5 g / cm³. This process is repeated until the entire dental restoration 100 has been built up layer by layer.

[0031] In the case of ZrO2 slurries 109, different yttrium-doped ceramic powders (3 mol% yttrium - 3Y-TZP, 4 mol% yttrium - 4Y-TZP, 5 mol% yttrium - 5Y-TZP) can be used to achieve different strengths. The yttrium doping also determines the degree of translucency. The different yttrium-doped ceramic powders exhibit different properties. 3Y-TZP = low translucency / high strength 4Y-TZP = medium translucency / medium strength 5Y-TZP = high translucency / low strength

[0032] However, if differently pre-colored slips 109 are used, each with different translucency and / or mechanical properties, each of these slips 109 is assigned its own printhead 111-1. For example, if a general CMYK color scheme is used to cover the entire color gamut, 3 x 4 = 12 slips 109 are contained in 12 printheads. The production of these various slips 109 is also complex. This large number of slips 109 are stored and maintained as separate items.

[0033] Fig. 3 Figure 1 shows a schematic representation of a manufacturing device 200 for producing a dental restoration 100 by jet printing (inkjet printing) of aqueous or solvent-based slurries 109. To additively manufacture ceramic, dental multi-material and multicolor restorations 100 by jet printing, base slurries 109 are processed.

[0034] The production apparatus 200 comprises a plurality of receiving containers 119-1 in which the base slurries 109 with different optical properties are arranged. The production apparatus 200 also comprises at least several receiving containers 119-2 in which the staining solutions 107 are contained. Additionally, the production apparatus 200 comprises a receiving container 119-3 in which a fixative solution 115 is contained.

[0035] The ceramic slips 109 are applied drop by drop in several layers 117-1, ..., 117-n using an associated printhead 111-1 to build up the dental restoration 100 layer by layer. The printhead 111-1 is movable in two directions, so that the slip 109 can be printed at any position. The printhead(s) can also be fixed in place, and the build platform moves in the three spatial directions beneath the printheads.

[0036] For selective material application, slurries 109 with a droplet volume of typically 10 to 100 pL are used, eliminating the time-consuming debinding process. Electrically controlled piezoelectric elements, for example, are used to eject the droplets.

[0037] For applying the dye solutions 107, a further printhead 111-2 is used, through which the dye solutions 107 can be jet-printed onto one or more layers 117-1, ..., 117-n. The printhead 111-2 is also movable in two directions, so that the dye solutions 107 can be printed at any position. The printheads 111-1 and 111-2 can be controlled independently of each other or integrated in a common print module. The printheads 111-1 and 111-2 can also be fixed in place, with the build platform moving in the three spatial directions beneath the printheads.

[0038] The fixing solution 115 is applied by a further application device 121, which may be formed by a spray head for applying the fixing solution 115 over a surface or by a further print head for selectively applying the fixing solution 115.

[0039] A drying device 123 is provided for drying the aqueous material, enabling the layers 117-1, ..., 117-n, the dye solution 107, and the fixative solution 115 to be dried without cracking. The drying device 123 is formed, for example, by a blower and / or an infrared radiator.

[0040] The manufacturing device 200 provides a reduced number of pre-stained and yttrium-doped neutral base slurries 109 to minimize the number of printheads 111-1 and 111-2 while still achieving an aesthetic and functional result for the dental restoration 100. Coloring is achieved separately by the selective application of staining solutions 107.

[0041] The desired tooth color is composed and mixed from the pre-stained staining solutions 107. A subtractive color system is used, which covers a limited dental color gamut. The color mixing, the three-dimensional halftoning or dithering, of these pre-stained slurries 109 in various ratios then occurs within this limited dental color gamut, which covers the common tooth colors, but not all colors.

[0042] Different staining solutions 107 are selectively applied to a layer 117-1, ..., 117-n using a 3D dithering algorithm executed by a dithering module 113. The dithering module 113 comprises a processor for executing the 3D dithering algorithm and a digital data storage unit for storing the calculated mixing ratios and the dithering algorithm. The processor includes any hardware system, component, or mechanism that processes data, signals, or other information. A processor can include a system with a central processing unit (CPU), multiple multiprocessing units (MPUs), a dedicated electrical circuit for achieving functionality, or other systems. The data storage unit can include hard disks, flash memory cards, random access memory (RAM), or read-only memory (ROM).

[0043] In dithering, the different staining solutions are selectively applied in a specific ratio and two-dimensional print pattern to the printing plane using a jet printing process. The 3D dithering algorithm also calculates that non-identical two-dimensional dithering patterns are applied in multiple layers 117-1, ..., 117-n. This prevents optical artifacts such as banding or moiré patterns on vertical surfaces. The color mixing, three-dimensional halftoning, or dithering of these pre-stained slurries 109 in various ratios occurs within the limited dental color gamut, which covers the common tooth shades but not all general colors.

[0044] When using highly viscous slurries 109 with a viscosity exceeding 100 mPas and a high filler content, special demands are placed on the printhead 111-1 and its fluid system. The printhead 111-1 must be compatible with the binder and / or carrier material of the slurry 109 to prevent incompatibilities and consequences such as corrosion of the printhead.

[0045] After selective application of a layer 117-1, ..., 117-n of slip 109 using the jet printing process, this layer 117-1, ..., 117-n is dried crack-free by evaporating the water or solvent used as a binder. The ceramic powder of slip 109 may already be tinted in a color, for example, a base color or tooth shade. What remains is a porous white layer with a thickness of 1 µm to 50 µm and a density of xx%. This process is repeated until the entire dental restoration 100 is built up layer by layer.

[0046] If two slips 109 with different translucencies are available, the high-strength and opaque slip 109 can be used for the dentin core and the normal-strength and highly translucent slip 109 for the incisal edge. Selective staining is carried out after each 1-n layer 117-1, ..., 117-n of material application by selective jet printing of staining solutions, such as nitrate solutions (acids), according to a corresponding color code or color information.

[0047] Fig. 4 Figure 1 shows a schematic view of a process for producing the dental restoration 100 by jet printing. In step S201, a selective layering of a slurry 109 is applied using a jet printing process (inkjet process) for 1-n layers 117-1, ..., 117-n.

[0048] In step S202, the applied slurry layer is dried, for example, by supplying warm air. In step S203, the 1 to n applied layers 117-1, ..., 117-n of the slurry 109 (green body layers) are selectively stained using staining solutions. The staining solutions are also printed onto the 1 to n applied layers 117-1, ..., 117-n using jet printing. In step S204, the printed staining solutions are locally fixed using a fixing solution, i.e., an alkaline solution with a pH value greater than 7 (alkali). Subsequently, steps S201 to S204 are repeated until the dental restoration 100 is completely built up in three dimensions.

[0049] Either aqueous or solvent-based slurries 109 can be processed using this method. Selective material application (step S201) and selective coloring (step S203) are carried out separately. The process has the technical advantage that, with dried, i.e., anhydrous, layers 117-1, ..., 117-n, the pH value of the coloring solution plays virtually no role.

[0050] Fig. 5 Figure 3 shows a schematic view of another method for producing the dental restoration 100 by jet printing. In step S301, a layer-by-layer selective application of a basic slurry 109 is carried out using a jet printing process (inkjet process) for 1-n layers.

[0051] The basic slurry 109 has a pH value greater than 7. A typical basic slurry 109 contains H₂O, dispersing agents, such as 0 to 5 wt.%, preferably 0.01 to 5 wt.%, carboxylic acid derivatives (citric acid) or 0 to 5 wt.%, preferably 0.01 to 5 wt.%, ammonium polyacrylic acid (NH₄PAA). The pH value (8–11) can be adjusted with NH₄OH. The basic composition of the slurry 109 has the advantage that the ceramic slurry 109 is less corrosive to the metal parts of the printhead.

[0052] In step S302, the still wet and undried applied layers 117-1, ..., 117-n of the slip 109 (green body layers) are selectively dyed using the dye solutions. A precipitation reaction occurs as soon as the nitric acid (dye solution) comes into contact with the moist slip 109.

[0053] In step S303, the staining solutions are automatically fixed by contact with the basic slurry 109. In step S304, the wet-on-wet stained layers 117-1, ..., 117-n are dried without cracking, for example by supplying warm air. Subsequently, steps S301 to S304 are repeated until the dental restoration 100 is fully built up.

[0054] Either aqueous or solvent-based slurries 109 can be processed using this method. Selective material application (step S301) and selective coloring (step S302) are carried out separately.

[0055] If no basic slurry 109 is used, the dye solution 107 diffuses into layers 117-1, ..., 117-n. The applied dye solution is fixed by separately applying the fixing solution, such as an alkali.

[0056] In this process, the slip 109 is stabilized in the acidic pH range. After printing and drying the individual layers, a basic fixative solution, such as 0.1 N ammonium hydroxide solution, is applied first. Subsequently, the dye solution 107 is applied. Upon contact of the dye solution with the layer treated with the fixative solution, the pH of the dye solution shifts locally towards pH > 2. This shift in pH causes metal hydroxides, such as Fe(OH)3, to form locally at the points where the dye solution is to be fixed. This process is called precipitation or flocculation.

[0057] After printing and drying the individual layers, the dyeing solution and immediately afterwards the basic fixing solution can be applied, which in turn fixes the dyeing components in the desired position.

[0058] Fig. 6 Figure 1 shows a table with the compositions of different dye solutions 107. The dye solutions 107 are low-viscosity and can be jet-printed using either a DOD or bubble-jet inkjet printhead. This printhead can integrate multiple color channels for multi-color printing. The printhead can apply the dye solution to layers 117-1, ..., 117-n at a high resolution of 720 dpi.

[0059] With six printheads available, only one printhead is used for medium-translucency slurry 109 and one printhead for support material. With seven printheads available, two printheads are used, one each for opaque slurry 109 and highly translucent slurry 109, and one printhead is used for support material. The other four printheads are used for the staining solutions 107.

[0060] The dye solutions are aqueous nitrate salts or chloride salt solutions. For this purpose, various metal salts are used (e.g. Fe(NO3)3*9 H2O; Pr(NO3)3*6 H2O; Tb(NO3)3*5 H2O; Er(NO3)3*5 H2O; Mn(NO3)2*4 H2O; Co(NO3)2*6 H2O; Cr(NO3)3*9 H2O; Mg(NO3)2*6 H2O; Al(NO3)3*9 H2O; Cu(NO3)2*3 H2O; Zn(NO3)2*6 H2O; Y(NO3)3*6 H2O; La(NO3)3*6 H2O; Ce(NO3)3*6 H2O; Nd(NO3)3*6 H2O; Sm(NO3)3*6 H2O; Gd(NO3)3*6 H2O; Yb(NO3)3*6 H2O); Ni(NO3)2* 6H2O; Co(NO3)2 *6H2O; Ga(NO3)3* xH2O; In(NO3)3 xH2O, dissolved in different concentrations.

[0061] However, depending on the desired composition, the dye solutions 107 can also be significantly more concentrated. An increase in ion concentration, however, increases the viscosity or shifts the pH value into the acidic range (<7).

[0062] Fig. 7Figure 10 shows a block diagram of a process for fabricating a dental restoration 100 by jet printing. In step S101, the layers 117-1, ..., 117-n of the dental restoration 100 are jet-printed using the ceramic slurry 109. In step S102, the staining solution 107 is jet-printed onto one or more layers 117-1, ..., 117-n. Subsequently, in step S103, the fixative solution 115 is applied to fix the staining solution 107. These steps are repeated until the dental restoration 100 is completely built up.

[0063] If the staining solution 107 is jet-printed into the previously dried layer 117-1, ..., 117-n, and then moist slurry is applied to the previously dried and stained layer 117-1, ..., 117-n, the staining solution 107 may be re-dissolved and diffuse uncontrollably into the already built-up dental restoration 100. When jet-printing the staining solution 107 onto the dried layer 117-1, ..., 117-n, care must be taken to ensure that the penetration depth of the staining solution 107 is controllable. For example, if the infiltration depth is greater than one layer thickness, staining can only occur after multiple layers of slurry 109 have been applied.

[0064] Applying the fixative solution 115 locally fixes the staining solution 107, thus preventing uncontrolled diffusion or mixing through hydroxide precipitation. This can be achieved by applying a basic fixative solution 115, such as an ammonia-ammonium chloride buffer solution, over a large area or selectively to shift the pH. For example, the ammonia-ammonium chloride buffer solution comprises 987.8 g of water, 6.8 g of 25% ammonia, and 5.4 g of ammonium chloride.

[0065] A single slip 109 in a base color and medium translucency can be used for the additive material application of the dental restoration 100. The selective coloring of the slip 109 is achieved by jet printing (jetting) the staining solutions, which are then fixed.

[0066] Different printhead technologies can be used because the slurry 109 and the staining solution 107 have different rheological properties. The slurry 109 is highly viscous (10–1000 mPas depending on the shear rate) and contains a high weight-to-volume proportion of an abrasive filler in the form of ceramic particles. A low viscosity of the slurry 109 between 10–500 mPas is advantageous, and a viscosity between 10–100 mPas is even more advantageous. The higher the viscosity of the slurry 109, the more difficult it is to process with inkjet printheads. Furthermore, the printhead should be capable of jetting aqueous media.

[0067] In contrast, the staining solution 107 is low-viscosity (0.5–50 mPas). Since these are highly concentrated nitrate solutions, the printhead used should be nitrate-resistant. Furthermore, the volumes processed differ, with a ratio of approximately 98% for the slurry 109 and 2% for the staining solution 107. Selective application of staining solutions 107 can also be achieved using a multi-channel printhead 111-2.

[0068] The penetration or diffusion depth of the staining solution 107 can also be controlled by adjusting its viscosity. This is achieved by adding a suitable thickening agent to the staining solution 107 that is stable within the pH range of the staining solution, such as polyvinylpyrolidone (PVP).

[0069] The main volume is processed via the slurry 109, whereas a smaller volume of the staining solution 107 is processed. The staining solution 107 and the slurry 109 can be stored in differently sized receiving containers 119-1 and 119-2.

[0070] The fully assembled dental restoration 100 is then sintered in a sintering furnace. The slurries 109 and the staining solutions 107 can be adjusted to ensure uniform sintering behavior. The sintering kinetics can be homogeneously adjusted by modifying the individual staining solutions 107. The sintering activators are neutralized by the use or addition of sintering inhibitors.

[0071] For the selective coloring process, nitrate solutions can be used as coloring solution 107, regardless of whether the slurries 109 are already pre-colored or whether the coloring is carried out exclusively via the layer-by-layer selective application of the coloring solutions 107 during the additive, layer-by-layer manufacturing process.

[0072] Additionally, the opacity of the slip 109 of the dental restoration 100 can be adjusted by varying the proportions of yttrium or ytterbium in the staining solution. For example, yttrium, ytterbium, neodymium, and europium are used as translucency enhancers, and aluminum and silicon as opaque liquids. The yttrium content can be increased with a suitable staining solution. This allows for different opacity levels to be achieved in the dental restoration 100, such as opaque for the dentin core and translucent for the incisal edge. REFERENCE MARK LIST

[0073] 100 Dental restoration 101 Dentin core 103 Enamel 105 Tooth 107 Staining solution 109 Sludge 111 Printhead 113 Dithering module 115 Fixing solution 117 Layer 119 Pick-up container 121 Application device 123 Drying device

Claims

1. A method of producing a dental restoration (100) by jet-printing, comprising: - jet-printing (S101) one or more layers (117-1, ..., 117-n) of the dental restoration (100) using a ceramic slurry (109); - jet-printing (S102) a coloring solution (107) onto the one or more layers (117-1, ..., 117-n); characterized by - applying (S103) a fixing solution (115) for fixing the coloring solution (107).

2. The method according to claim 1, wherein the fixing solution (115) is sprayed onto the one or more layers (117-1, ..., 117-n).

3. The method according to claim 1, wherein the fixing solution (115) is jet-printed onto the one or more layers (117-1, ..., 117-n) by a print head (111).

4. The method according to any one of the preceding claims, wherein the one or more layers (117-1, ..., 117-n) are dried before or after jet-printing the coloring solution (107).

5. The method according to any one of the preceding claims, wherein the one or more layers (117-1, ..., 117-n) are dried before or after applying the fixing solution (115).

6. The method according to any one of the preceding claims, wherein a pH of the fixing solution (115) is greater than 7.

7. The method according to any one of the preceding claims, wherein the fixing solution (115) is an ammonia-ammonium chloride solution.

8. The method according to any one of the preceding claims, wherein the steps (S101, ..., S103) to produce the dental restoration (100) are repeated.

9. The method according to any one of the preceding claims, wherein the dental restoration (100) is sintered in a sintering furnace.

10. A production apparatus (200) for producing a dental restoration (100) by jet-printing, comprising: - a first print head (111-1) for jet-printing one or more layers (117-1, ..., 117-n) of the dental restoration (100) by means of a ceramic slurry (109); and - a second print head (111-2) for jet-printing a coloring solution (107) onto the one or more layers (117-1, ..., 117-n); and - an application device (121) for applying a fixing solution (115) for fixing the coloring solution (107); characterized by - a storage container (119-3) which receives a fixing solution (115).

11. The production apparatus (200) according to claim 10, wherein the application device (121) is formed by a spray head for applying the fixing solution (115) extensively.

12. The production apparatus (200) according to claim 10, wherein the application device (121) is formed by a print head (111) for selectively applying the fixing solution (115).

13. The production apparatus (200) according to any one of claims 10 to 12, wherein the production apparatus (200) comprises a drying device (123) for drying the applied materials.

14. The production apparatus (200) according to claim 13, wherein the drying device (123) comprises a blower and / or an infrared radiator.