Method for producing a decorated profile body

Abstract

The invention relates to a method for producing a decorated profile body (1), said method comprising the steps of: providing a polymeric substrate (2); applying a decorative layer (3) in the form of ink droplets (100) using a digital printing process; and applying at least one further layer (4, 4', 4'') using a liquid (5) having a dynamic viscosity of at least 20 mPas (at 40°C). According to the invention, the further layer (4, 4', 4'') is also applied using the digital printing process.

Description

[0001] Method for producing a decorated profile body

[0002] The invention relates to a method for producing a decorated profile body comprising the steps:

[0003] Providing a polymeric substrate,

[0004] Application of a decorative layer in the form of ink droplets using digital printing,

[0005] Application of at least one further layer using a liquid having a dynamic viscosity of at least 20 mPas (measured at 40°C).

[0006] The surface coating of substrates, particularly those made of plastic, with paints and varnishes is currently carried out using various application techniques, such as spraying, dipping, rolling or brushing. Corresponding substrates are extensively processed in the furniture and other industries, for example in the form of edge bands to cover the narrow sides of furniture panels, or more generally as profiles or films. The decorated profile body generally has a thickness of no more than 10 mm, in particular no more than 5 mm. Paints and varnishes with a wide viscosity range can be processed using the aforementioned methods. Solvent-based or solvent-free varnishes are also applied. In addition, digital printing is increasingly establishing itself as a modern, loss-free coating process for decorative printing on substrates, as described, for example, in EP 2 247 451 B1.A disadvantage of the known digital printing processes for applying decorations, however, is that the corresponding print heads used in digital printing can only process liquids with a low viscosity of less than 30 mPas (at 20°C). In order to reduce the viscosity and thus facilitate processability, it is therefore an established measure in the state of the art to first heat the liquid flowing through the print heads during digital printing to approximately 40°C, so that the viscosity at this processing temperature can be reduced to just 10 to 12 mPas. Despite this measure, however, the application of digital printing remains limited to low-viscosity liquids, so that in practice the decorated profile body is produced by combining the conventional application techniques mentioned above with digital printing for decorative coating on the polymer substrate.Due to the different coating processes used, the production of the profile bodies is comparatively complex and inflexible in terms of equipment.

[0007] Against this background, the object of the invention is to provide a method with the measures described above, which is characterized by high flexibility and, at the same time, low investment costs.

[0008] According to the invention, the object is achieved in that the further layer is also applied using a digital printing process. The further layer is expediently applied over the entire surface, e.g. with a layer thickness of at least 10 pm. According to the invention, it was recognized that by using appropriate print heads which can also process liquids with high viscosity, typical layers of a decorated profile body with a polymer substrate, such as priming layers or also surface layers with a high mechanical load, can be applied by means of digital printing. Although such print heads are already known in the prior art, e.g. from US 2017 / 282555 AA, they are used for printing ceramics with oil-based inks or in classic additive manufacturing processes (3D printers). Piezoelectric print heads are expediently used to apply the liquids with high viscosity.

[0009] There are fundamentally different possibilities for the arrangement of the further layer in the layer structure of the profile body. For example, the further layer can be designed as a primer layer arranged between the substrate and the decorative layer. It is also within the scope of the invention for the further layer to be designed as a base layer provided between the substrate and the decorative layer. The combination of an aforementioned primer layer with an aforementioned base layer is also within the scope of the invention, with the base layer expediently being arranged between the substrate and the primer layer. The further layer can alternatively or additionally be designed as a cover layer provided above the decorative layer, e.g. as a translucent or transparent lacquer layer.

[0010] Within the scope of the invention, a liquid with a viscosity of at least 30 mPas, preferably at least 50 mPas, e.g., at least 70 mPas (each measured at 40°C) can be used. With such a high viscosity, layers can be applied to the polymer substrate using the corresponding liquid that previously had to be applied conventionally. This broadens the application possibilities of digital printing and thus increases the flexibility of manufacturing the decorated profile body. The dynamic viscosity can be measured, for example, using a commercially available rotational viscometer.

[0011] At least one layer can be formed by means of the digital printing process in such a way that it has unevenness, thereby giving this layer an embossed appearance. For this purpose, the liquid preferably has a particularly high viscosity of, for example, at least 100 mPas, optionally at least 150 mPas, optionally at least 200 mPas, optionally at least 300 mPas, optionally up to 400 mPas, so that it only travels a comparatively short flow path after being ejected from the print head, thus allowing the creation of a sharply contoured embossed appearance. The average depth of the embossing is expediently at least 10 pm, preferably at least 50 pm. It is further within the scope of the invention that the liquid contains fillers, preferably with an average particle size of at most 10 pm, in particular at most 5 pm. These fillers can contribute to the appearance of the correspondingly produced layer, or can also, for example,influence the mechanical properties of the corresponding layer. Furthermore, it is within the scope of the invention that the printing of microstructures influences the light reflection in such a way that a matte appearance of the outer surface of the profile body is created. This printing can be carried out using high-gloss varnish, expediently without fillers. The microstructures preferably have an average depth of less than 10 pm, e.g., a maximum of 5 pm.

[0012] The decorative layer is advantageously combined with a decorative base layer arranged beneath the decorative layer, preferably also applied using a digital printing process. If necessary, all layers applied to the substrate can also be applied using a digital printing process. The substrate itself is usually made of a polymer material.

[0013] The substrate can be formed as an extruded or calendered profile, preferably as an edge band or wall connection profile, or as a film, for example with a layer thickness of less than 0.5 mm, in particular less than 0.3 mm. The substrate is expediently provided continuously and moves at a preferably constant speed v, which can be in the range of v = 5 to 40 m / min, in particular 10 to 30 m / min. The invention also relates to a decorated profile body produced using the above method. The invention is explained in detail below with reference to a drawing that represents only one exemplary embodiment. The following schematically show:

[0014] Fig. 1 shows a process diagram for producing a decorated profile body according to the prior art,

[0015] Fig. 2 is a view corresponding to Fig. 1, wherein the decorated profile body is produced according to the invention,

[0016] Fig. 3 shows a further production of a decorated profile body according to the invention and

[0017] Fig. 4 shows a sequential application of two layers, each with a highly viscous liquid, according to the invention.

[0018] Fig. 1 shows a method for producing a decorated profile body 1 according to the prior art. First, an endless polymeric substrate 2 moving at a speed v is continuously provided. A base layer 4 is first printed onto the substrate 2 using a conventional method, in the exemplary embodiment using rotating rollers 50. A primer layer 4' is then applied to this base layer 4, likewise conventionally using rollers 50. A decorative layer 3 in the form of ink droplets 100 is then applied using a digital printing method using digital print heads 200. Finally, a top coat (e.g., a matt varnish) 4" is applied, again conventionally, using rotary roller printing using rollers 50. The primer layer 4' serves to ensure good adhesion of the ink droplets 100 to the decorated profile body 1.The layers 4, 4', 4" are each produced using a liquid 5 having a dynamic viscosity of at least 20 mPas (at 40°C). In the exemplary embodiment, the polymeric substrate 2 is formed as an extruded or calendered profile, preferably as an edgeband or wall connection profile. Suitable polymer materials include, for example, PP, PMMA, PVC, or the like. Furthermore, the layers 4, 4', 4" are each applied over the entire surface of the respective underlying layer.

[0019] In the inventive method according to Fig. 2, in addition to the decorative layer 3, the further layers 4, 4', 4" are all also applied over the entire surface using a digital printing process. The liquids 5 used to provide the layers 4, 4', 4" can have a viscosity of at least 30 mPas, e.g. at least 50 mPas, for example at least 70 mPas (each measured at 40°C). The application of the comparatively highly viscous liquids 5 takes place using suitable digital print heads 200', such as those known from 3D printing processes or from the printing of ceramics.

[0020] In the exemplary embodiment, the final cover layer 4" is further formed by means of the digital printing process in such a way that it has unevenness, thereby imparting an embossed appearance to this layer 4" and thus to the entire profile body 1. The average depth of the embossing is at least 10 pm, preferably at least 50 pm (not shown in detail). The liquid 5 for producing the cover layer 4" contains fillers that influence the appearance of the cover layer 4", e.g., with an average particle size of at most 10 pm, in particular at most 5 pm.

[0021] In the embodiment according to Fig. 3, the decorative layer 3 is combined with a decorative base layer 3' arranged below the decorative layer 3 and also applied using the digital printing process.

[0022] Fig. 4 describes the application of a varnish layer 4" covering the top of the profile body 1 to an underlying layer, generally designated 40, using a two-stage process. The combination of two successive print heads 200' with high-gloss varnish 5' on the one hand and matt varnish 5" on the other hand enables digital adjustment of the gloss level. The high-gloss varnish 5' and the matt varnish 5" are each located in separate storage containers 110. The high-gloss varnish 5' is first passed through a filter 120 and then passes through a conveyor device 130 and a pressure measuring unit 140 before being fed to a first print head 200'. The matt varnish 5", on the other hand, is fed directly to a second print head 200". Excess varnish 5' or 5" is recycled. Both print heads 200' are controlled via a data processing unit (e.g. computer).First, the high-gloss varnish 5' is applied over the entire surface, followed immediately by the matt varnish 5". The layer thickness of the high-gloss varnish layer 50' and the matt varnish layer 50" is 1 - 15 pm each. Both the high-gloss varnish 5' and the matt varnish 5" each have a dynamic viscosity of approximately 100 mPas, measured at 40°C. The application speed v (= feed speed of the substrate) can be more than 10 m / min, e.g., more than 20 m / min, and for example, a maximum of even 30 m / min. Both the high-gloss varnish layer and the matt varnish layer applied thereon are then subjected to online UV curing, with the profile body 1 being guided past a correspondingly suitable device 160 for this purpose.

[0023] Patent claims

Claims

Patent claims 1. A method for producing a decorated profile body (1) comprising the steps: - Providing a polymeric substrate (2), - applying a decorative layer (3) in the form of ink droplets (100) using a digital printing process, - applying at least one further layer (4, 4', 4") using a liquid (5) having a dynamic viscosity of at least 20 mPas (at 40°C), characterized in that the further layer (4, 4', 4") is also applied using the digital printing process.

2. Method according to claim 1, characterized in that the further layer (4, 4', 4") is formed as a primer layer (4) and / or base layer (4') arranged between the substrate (2) and the decorative layer (3) and / or as a cover layer (4") provided above the decorative layer (3).

3. Method according to claim 1 or 2, characterized in that a liquid (5) with a viscosity of at least 30 mPas, preferably at least 50 mPas, e.g. at least 70 mPas (each at 40°C) is used.

4. Method according to one of claims 1 to 3, characterized in that at least one layer (4") is formed by means of the digital printing process in such a way that it has unevenness and this gives this layer (4") an embossed appearance.

5. Method according to claim 4, characterized in that the average depth of the embossing is at least 10 pm, preferably at least 50 pm.

6. Method according to one of claims 1 to 5, characterized in that the liquid (5) contains fillers, preferably with an average particle size of at most 10 pm, in particular at most 5 pm.

7. Method according to one of claims 1 to 6, characterized in that the decorative layer (3) is combined with a decorative base layer (3') arranged below the decorative layer (3), preferably also applied by digital printing.

8. Method according to one of claims 1 to 7, characterized in that all layers (3, 3', 4, 4', 4") applied to the substrate (2) are applied by means of a digital printing process.

9. Method according to one of claims 1 to 8, characterized in that the substrate (2) is formed as an extruded or calendered profile, preferably as an edge band or wall connection profile, or as a film, for example with a layer thickness of less than 0.5 mm, in particular less than 0.3 mm.

10. Decorated profile body (1) produced by a method according to one of the claims 1 to 9.

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