DIRECTLY PRINTED PANEL HAVING A TWO-LAYER DESIGN

Abstract

A panel and a method for manufacturing of such a panel with a carrier plate, comprising a front side and a back side, and wherein the carrier plate comprises a layer system at least at the front side that is built from various polymer layers with different hardness values.

Claims

1. A panel, in particular a wall panel, ceiling panel, or floor panel, comprising a carrier plate having a front side and a back side, wherein the carrier plate has a layer system at least at the front side, and the carrier plate comprises coupling means in terms of tongue and groove elements at its sides, enabling coupling of various similar panels in parallel direction to the front side and perpendicular to the front side by form fitting, wherein the layer system, originating of the front side, comprises: a first elastic layer S1 made of an polymer, having a thickness of 20 to 600 m and a Martens hardness M.sub.S1 of 0.5 to 120 N/mm.sup.2; a second layer S2 made of a polymer, having a thickness of 10 to 180 m and a Martens hardness M.sub.S2, wherein M.sub.S2>M.sub.S1; and a decor layer arranged between the front side and the layer S1, comprising a printing ink; the printing ink is based on a polymerizable acrylate and/or N-vinylcaprolactam.

2. The panel according to claim 1, wherein the polymer of the layer S1 is an aliphatic polymer.

3. The panel according to claim 1, wherein M.sub.S1 is between 2 and 50 N/mm.sup.2, more preferably between 2 and 40 N/mm.sup.2, and most preferably between 2 and 30 N/mm.sup.2.

4. The panel according to claim 1, wherein M.sub.S2 is between 50 and 300 N/mm.sup.2, preferably 15 and 150 N/mm.sup.2, more preferably between 20 and 100 N/mm.sup.2, and most preferably between 25 and 90 N/mm.sup.2.

5. The panel according to claim 1, wherein the first elastic layer S1 has a thickness of 40 to 500 m, preferably of 80 to 450 m, and most preferably of 120 to 240 m.

6. The panel according to claim 1, wherein the second elastic layer S2 has a thickness of 10 to 180 m, preferably of 20 to 100 m, and most preferably of 30 to 80 m.

7. The panel according to claim 1, wherein the polymer of the layer S1 is based on a radiation hardened aliphatic acrylate, particularly an aliphatic urethane acrylate.

8. The panel according to claim 1, wherein a third elastic layer S3 is arranged between the front side and decor layer, having a Martens hardness M.sub.S3, wherein M.sub.S3M.sub.S1.

9. The panel according to claim 9, wherein the layer S3 has a thickness of 10 to 300 m, preferably of 30 to 150 m, and most preferably of 60 to 120 m.

10. The panel according to claim 1, wherein the printing ink of the decor layer and at least a part of the layer S1 have been hardened together, preferably by radiation.

11. The panel according to claim 1, wherein the decor layer has been applied by digital printing.

12. The panel according to claim 1, wherein the polymer of the layer S2 is based on one or more of the following acrylates: 1,6-hexandioldiacrylate, polyester acrylate, polyurethane acryl acid ester and dipropylene glycole diacrylate.

13. The panel according to claim 1, wherein the carrier plate has a thickness between 3 and 20 mm, preferably between 4 and 15 mm, more preferably between 3 and 12 mm, and most preferably between 4 and 10 mm.

14. The panel according to claim 1, wherein the carrier plate is a MDF plate, a HDF plate, a PVC plate, a cement fiber plate, a WPC plate (wood powder composite), a thermoplastic recycling plate, wood plate, a wood veneer plate, or a parquet plate.

15. The panel according to claim 1, wherein no paper or plastic foil is applied to the front side of the panel.

16. The panel according to claim 1, wherein the source materials of the layers S1, S2, and S3 are radiation hardenable materials.

17. The panel according to claim 1, wherein the layers S1 and S2 are transparent.

18. The panel according to claim 1, wherein the panel is not provided with abrasion-resistant particles, in particular aluminium oxide particles.

19. The panel according to claim 1, wherein the layer system has a damping effect of at least 5 dB, preferably at least of 8 dB, and most preferably of at least 9 dB, compared to the uncoated carrier plate, measured according to EPLF norm.

20. The panel according to claim 1, wherein the hardness of the elastic layer S1 is substantially constant over the total thickness, and in that the hardness differences within the layer are particularly less than 20 N/mm.sup.2, preferably less than 15 N/mm.sup.2, and more preferably less than 10 N/mm.sup.2.

21. A method for manufacturing a panel, particularly a wall panel, ceiling panel, or floor panel, comprising the following steps in the given order: (a) providing a carrier plate; (a1) applying a base coat and imprinting a decor layer thereon, wherein the decor layer is imprinted by means of a polymerizable printing ink based on a polymerizable acrylate and/or N-vinylcaprolactam; (b) applying a coat of liquid radiation hardenable aliphatic acrylate, having a Martens hardness Msi of 0.5 to 120 N/mm.sup.2 after curing; (c) at least partially curing of the in step (b) applied coat of liquid radiation hardenable aliphatic acrylate by means of radiation; (d) optionally repeating the steps (b) and (c) until a first elastic layer S1 with a thickness of 20 to 600 m exists; (e) applying a coat of liquid radiation hardenable acrylate, having a Martens hardness M.sub.S2 after curing, wherein M.sub.S2>M.sub.S1; (f) at least partially curing the in step (e) applied layer of liquid radiation hardenable aliphatic acrylate by means of radiation; (g) optionally repeating the steps (e) and (f) until a second layer S2 exists, having a thickness of 10 to 180 m.

22. The method according to claim 21, wherein the printing ink and the at least one applied coat of liquid radiation hardenable aliphatic acrylate are cured together by radiation.

23. The method according to claim 21, wherein MS1 is 2 to 50 N/mm.sup.2, preferably 2 to 40 N/mm.sup.2, and most preferably between 2 to 30 N/mm.sup.2 after curing.

24. The method according to claim 21, wherein MS2 is 5 to 300 N/mm.sup.2, preferably 15 to 150 N/mm.sup.2, more preferably 20 to 100 N/mm.sup.2, and most preferably 25 to 90 N/mm.sup.2 after curing.

25. The method according to claim 21, wherein the steps (b) and (c) are repeated until the first elastic layer S1 has a thickness of 40 to 500 m, preferably of 80 to 450 m, and most preferably 120 to 240 m.

26. The method according to claim 21, wherein the steps (e) and (f) are carried out until the second layer S2 has a thickness of 10 to 180 m, preferably of 20 to 100 m, and most preferably of 30 to 80 m.

27. The method according to claim 21, wherein the applying in the steps (b) and (e) is done by rollers.

Description

4. DESCRIPTION OF PREFERRED EMBODIMENTS

[0045] In the following, the present invention is explained in more detail with reference to the attached figures. At this:

[0046] FIGS. 1a and b show an exemplary layer structure of a schematic illustration; and

[0047] FIG. 2 shows an exemplary system for manufacturing of the panel according to the invention in a schematic view.

[0048] In FIG. 1a, a schematic layer structure of a panel 10 according to the invention is shown. The illustration is purely schematic and not true to scale. In particular, the carrier plate 11 is significantly thicker compared to the further layers 12-18, which lie in a range of some hundred pm. Furthermore, the single layers are shown in an explosion view in order to simplify the understanding and are in a real case directly adjacent to each other or directly arranged above each other. In the shown example, a carrier plate 11 with a thickness of about 8 mm made of an HDF material is shown. At the backside of the carrier plate 11 a moisture barrier 13 in form of an appropriate plastic foil is pasted. The moisture barrier is optional and depending on the material of the carrier plate 11 and the desired usage area. A carrier plate 11 furthermore comprises coupling means in form of tongue 15 and groove elements 14, which are only shown schematically in FIG. 1a (and b). Suitable coupling means in form of tongue and groove elements that allow connecting various similar panels in parallel direction of the front side and also perpendicular to the front side by means of form fitting are known by the skilled person. Commonly, at the four sides of a square or quadrangle carrier plate opposing complementary coupling means are provided. Details about such coupling means or locking profiles are known by the skilled person from the technology of laminate floor production, as e.g. known from the document WO 0188306 or from the document WO 0148332 of the same applicant, which are hereby entirely incorporated by reference.

[0049] In the shown layer system of panel 10, a primer coating 16 with a thickness of, for example, 50-200 m is provided which is based on a watery acrylate system. Beneath the primer, further very thin primer coatings and/or filler layers may be applied as known by the skilled person from the area of direct imprinted panels. A decor layer or a decor 18 is imprinted onto the primer 16. The decor 18 or the decor layer 18 have been applied, for example, by means of a polymerizable printing ink by a digital four color printing. A first elastic layer S1 is located above the decor layer 18 with a thickness of 200 m and a Martens hardness M.sub.S1 of 15 N/mm.sup.2. A second layer S2 is applied onto the first elastic layer S1, which has a thickness of 80 m and a Martens hardness of about 25 N/mm.sup.2.

[0050] The example of FIG. 1b corresponds to the example of FIG. 1a with the difference that a further elastic layer S3 is provided between the primer coating 16 and the decor layer 18. The layer S3 has preferably a Martens hardness Mss which is less or equal than the Martens hardness of the layer S1, therefore M.sub.S3M.sub.S1. In the example of FIG. 1b, the first layer S1 may be provided in a slightly thinner way compared to the example of FIG. 1a which is shown in both figures schematically by means of different thicknesses.

[0051] In the following, the manufacturing of a panel according to the invention is exemplarily shown in FIG. 2. FIG. 2 shows in a schematic way a coating system for coating carrier plates 11. The carrier plates are trimmed and profiled after the coating in a separate profiling line (not shown). For example, the carrier plates 11 have a thickness between 3-20 mm, a length (in transport direction of the system of FIG. 2) of 150-200 cm and a width of 125-210 cm. However, any other plate dimensions can be used for the carrier plates, which are cut in the desired form and size at the end of the process. The stations shown in FIG. 2 of the system are not to be understood conclusive, but only serve as an example explanation of the methods according to the invention. In front, behind and between the shown stations, further processing stations may be provided, like drying stations, stations for applying primers, stations for applying filler, control and monitor devices etc. The carrier plates 11 are, for example, transported through the coating system by means of roller conveying device 20.

[0052] In the first shown station 30, a grounding mass is applied onto the front side (main side) of the carrier plates 11 by means of a liquid curtain 31 of coating material. The liquid curtain 31 ranges among the complete width of the plate and the plates are transported through this curtain and are coated at the same time. Below the device 30 for outputting the curtain, a collection container 32 is located, in which the liquid curtain drops, when no plate is passed through the curtain, as for example, at a gap between two consecutive plates. Preferably, a watery acrylate dispersion is used as a coating material for the grounding. In a subsequently arranged drying station 40, the applied grounding is dried by means of hot air, i.e. water is extracted from the watery acrylate dispersion. After drying the grounding, a decor layer is imprinted onto the grounding by means of a digital printing device 45. This decor layer, for example, can imitate real wood, but nowadays commercial digital printing works are able to nearly print every desired decor or pattern on the plates. Preferably, a printing ink is utilized in printing device 45 that is polymerizable by means of radiation, i.e. a printing ink that is based on a polymerizable acrylate and/or N-vinylcaprolactam. It is apparent for the skilled person that the illustration of the digital printing device 45 is only purely schematic and that such printing devices commonly consist of several stations. After imprinting the desired decor, a first coating device 50 applies a first layer of liquid radiation hardenable aliphatic acrylate. The material is chosen in such a way that it comprises a Martens hardness M.sub.S1 of 0.5-120 N/mm.sup.2 after the curing. The device 50 is a roller application device and is able to apply a layer thickness of about 40-100 m in one process step. In the subsequent station 60, the applied layer of liquid radiation hardenable aliphatic acrylate is cured at least in part by means of UV radiation. Subsequently, a second device 50 follows in order to apply a second layer of the same liquid radiation hardenable acrylate compared to the first layer. Also here, the station 50 is a roller application station which is commonly able to apply layer thicknesses of 30-100 m. In station 60 this second layer is at least cured in part by UV radiation. Subsequently, in a third coating device 50 a third layer of the same liquid radiation hardenable acrylate is applied and in the third radiation station 60 it is at least in part cured by means of UV radiation. In the schematic view of FIG. 2 three such devices are thus shown, which are able to apply three layers in one layer, but however, also more or less devices may be available, depending on the desired total thickness of the first elastic layer S1. In any case, there is a first elastic layer S1 available at the exit of the last radiation station 60 with a thickness of about 150 m. Then, onto this first elastic layer S1, a layer of liquid radiation hardenable acrylate is applied in an application station 70 that is chosen in a way such that after the curing it comprises a Martens hardness M.sub.S2 that is greater than the Martens hardness of the first elastic layer and preferably at 5-300 N/mm.sup.2. Here, in FIG. 2, as an example, only an application device 70 and a station 71 for radiation hardening is shown, but however, also for the second layer S2 various devices may be provided, depending on the desired final thickness of the layer of S2. Then at the exit of the coating device, a coated panel, according to the invention will be available, that may be further processed as desired.