METHOD FOR MANUFACTURING A DECOR SHEET FOR DECORATIVE PANEL

Abstract

A method is provided for manufacturing a decorative sheet for decorative panels. The method may involve providing a first printed substrate having a printed color patch having at least one printed color spot. The first printed substrate may be subjected to at least a predetermined operation that causes a color shift of the color spot. A first color coordinate set may be determined for the color spot. A first ICC profile may be determined using the first color coordinate set. A first master image may be visualized on a display device using the first ICC profile. An image processing operation may be performed on the first master image to obtain a second master image during the visualization. The second master image may be printed on a second substrate to obtain the decorative layer.

Claims

1. A method for manufacturing a decorative sheet for decorative panels, the method: a) providing a first printed substrate having a printed color patch having a printed color spot; b) subjecting the first printed substrate to at least a predetermined operation that causes a color shift of the color spot; c) determining a first color coordinate set for the color spot after the predetermined operation; d) determining a first ICC profile using the first color coordinate set; e) visualizing a first master image on a display device using the first ICC profile; f) performing an image processing operation on the first master image to obtain a second master image during the visualization; g) printing the second master image on a second substrate to obtain the decorative layer.

2. The method according to claim 1, wherein the second master image is printed using a second ICC profile.

3. The method according to claim 1, wherein step a) involves: providing a first printable substrate; and printing the color patch on the first printable substrate to obtain the first printed substrate.

4. The method according to claim 3, wherein the color patch is printed using a second ICC profile that is the same as that used to print the second master image.

5. The method according to claim 1, wherein the first substrate and/or the second substrate comprises paper layer or a thermoplastic foil.

6. (canceled)

7. The method according to claim 1, wherein the predetermined operation is one of impregnating, heating, pressing, gluing, covering with a transparent layer and/or laminating.

8. The method according to claim 1, wherein the printing is an inkjet printing.

9. The method according to claim 1, wherein the second substrate comprises one or more features in common with the first substrate.

10. The method according to claim 1, wherein the second substrate is the same as the first substrate.

11. (canceled)

12. The method according any to claim 1, wherein the first substrate is subjected to multiple predetermined operations, each causing a color shift.

13. The method according to claim 12, wherein sets of color coordinates measured after each predetermined operation are stored in a database.

14. The method according to claim 13, wherein the method involves planning one or more predetermined operations to be performed on the decorative sheet; and determining the first ICC profile on the basis of the plan and on the sets of color coordinates stored in the database.

15. The method according to claim 1, wherein a second color coordinate set is determined for the color spot before performing the predetermined operation.

16. The method according to claim 1, wherein the predetermined operation is performed multiple times on multiple first substrates; wherein a first color coordinate set is determined for each first substrate to obtain a plurality of first color coordinate sets for the color spot; and wherein the first ICC profile is determined on the basis of the plurality of first color coordinate sets.

17. (canceled)

18. The method according to claim 1, wherein the printing is performed using one or more inks.

19. The method according to claim 18, wherein the inks are selected from the group comprising: cyan, magenta, red, yellow, black, light cyan, light magenta, and light red.

20. (canceled)

21. A method for manufacturing a decorative panel having a top layer with a decorative sheet, wherein the decorative sheet is obtained according to the method of claim 1.

22. The method according to claim 21, wherein further comprising performing the predetermined operation on the decorative sheet.

23. The method according to claim 21, wherein the panel comprises a substrate.

24. The method according to claim 21, further comprising providing a transparent layer on top of the decorative sheet.

25. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] With the intention of better showing the characteristics according to the invention, in the following, as an example without limitative character, an embodiment is described, with reference to the accompanying drawings, wherein:

[0063] FIG. 1 schematically shows a top view of a decorative sheet obtainable through the method of the invention;

[0064] FIG. 2 shows an enlarged view of a section according to plane II-II of FIG. 1;

[0065] FIG. 3 schematically shows some steps in a method in accordance with the first aspect of the invention;

[0066] FIG. 4 schematically shows a top view of a printed substrate used in the method of the invention;

[0067] FIG. 5 schematically shows some steps in a method for manufacturing laminate panel;

[0068] FIG. 6 shows a perspective view of a panel obtainable through the method of FIG. 5; and

[0069] FIG. 7 shows some steps of an alternative embodiment of the method of the invention.

DESCRIPTION OF NON-LIMITING EMBODIMENTS

[0070] FIG. 1 a decorative sheet 1 for laminate panels obtainable through the method of the invention. Said decorative sheet 1 comprises a printed substrate 2 having a decorative pattern 3 on one of its surfaces. In the example, the decorative pattern 3 represents a wood dcor.

[0071] FIG. 2 shows an enlarged view of the section along plane II-II of FIG. 1. FIG. 2 shows that the printed substrate 2 comprises a base paper 4 and an ink receiver layer 5 that coats the surface of the base paper layer 4 that is provided with the printed pattern 3.

[0072] The base paper 4 of the embodiment comprises a weight, i.e. without an ink receiving layer 5, higher than 20 grams per square meter, preferably between 50 to 100 grams per square meter, e.g. between 60 and 80 grams per square meter. Preferably, the base paper 4 comprising the ink receiver layer 5 shows a resin penetration time lower than 3 sec. Preferably, the base paper 4 is opaque and/or contains titanium oxide as a whitening agent and/or other inorganic fillers. Alternatively, the base paper 4 may be a colored, pigmented and/or dyed base paper. The base paper 4 can show a mean air resistance as expressed in Gurley value below 40 sec, preferably below 25 sec.

[0073] In the example the ink receiver coating 5 comprise polyvinyl-alcohol as binder, silica particles as pigments and a cationic metal salt chosen from the list consisting of CaCl.sub.2, MgCl.sub.2, CaBr.sub.2, MgBr.sub.2, CMA (Calcium Magnesium Acetate), NH.sub.4Cl, Calcium Acetate, ZrCl.sub.4, calcium nitrate and Magnesium Acetate.

[0074] Said ink receiver coating 5 is provided in a predetermined amount between 0.5 g/sqm and 5 g/sqm on the base paper sheet 4.

[0075] FIG. 3 shows some step of a method for obtaining the decorative sheet 1. The method comprises a first step of providing a first printed substrate 10 as shown in FIG. 4. The first printed substrate 10 preferably comprises a base paper 4 and an ink receiver layer 5 as described above in relation to the decorative sheet 1. The first printed substrate 10 comprises a color chart 11 having a plurality of color spots 12. Each color spot 12 comprises a printed color characterized by a specific color having respective visual color coordinates. Said color coordinates can be identified in the CIELAB space. The color chart 11 is preferably printed by inkjet printing using a plurality of inks preferably selected from the group comprising: cyan, magenta, red, yellow and black, possibly with the addition of spot-colors like light magenta, light yellow, green etc. Thereto each color spot 12 comprises also a set of color coordinate that can be expressed in the CMYK or CRYK space. In particular, each color spot 12 is composed by a certain percentage (from 0% to 100%) of at least one of the printed colors forming the set of inks, thereto each color spot is also defined in terms of color tones.

[0076] The first substrate 10 is subjected to a predetermined operation shown in FIG. 3. In the example, the predetermined operation involves impregnating the first substrate 10 with a thermosetting resin 15, in particular a melamine-based resin. In particular, the first substrate 10 is transported to a first impregnation station 16 where said first substrate 10 is immersed in a bath 17 of said thermosetting resin 15, more particularly a mixture of water and thermosetting resin composition. The first substrate 10 is then allowed to rest while in this case being transported upwards. The resting allows for the resin 15 to penetrate the core of the first substrate 10. The first substrate 10 then comes into a second impregnation station 18 where it is, in this case, again immersed in a second bath 17 of resin 15, more particularly a mixture of water and resin. A set of squeezing rollers and doctor blades 19 allows to dose the amount of resin applied to the first substrate 10.

[0077] The first substrate 10 is then dried and its residual humidity level is brought to below 10%. In the example a hot air oven 20 is used, but alternatively other heating equipment can be used, such as microwave or infrared drying equipment.

[0078] In the example the first substrate 10 is cut to sheet 21 and heat pressed between a substrate 22, for example made of MDF, and a transparent layer 26 by means of a hot press 23. Said transparent layer can be for example a resin impregnated overlay paper.

[0079] The heat pressing causes a color variation at the color spots 12 in the color chart 11. Although the CMYK or CRYK color coordinates of the printed color spots 12 remain the same, the visual color coordinate in the CIELAB space change. The new color coordinate can be measured with a scanner or a spectrophotometer 24 to obtain a first set of color coordinates for each color spot 12.

[0080] Said first sets of color coordinates are sent to a processing unit PU, that determines a first ICC profile that is configured to simulate the visual appearance of the color chart, after the color change, on a display device 25, preferably the monitor of a personal computer.

[0081] The first ICC profile is used to visualize on said display device 25 a first master image, in the example a scanned image of a real natural wood. In this way a graphic designer can visualize on the display device 25 what will be the color change after printing and after the predetermined operation. Therefore, the operator can perform an image processing operation on said first master image while visualizing it through the first ICC profile, so that what will be the final visual result on a laminate panel can be simulated, to thereby obtaining a second master image.

[0082] Subsequently a blank paper layer 4 as described with reference to FIG. 2 can be uncoiled from a first roll 30 and fed to a coating station 31 to be coated with the ink receiver layer 5, having the features described above, to obtain a second printable substrate 32.

[0083] The second printable substrate 32 is transported to a printer 33 for printing the second master image on the second printable substrate 32. The printer 33 of the example is a single pass inkjet printer configured to print with a plurality of ink, preferably at least four inks selected from the group comprising: cyan, magenta, red, yellow, black. The inks are preferably pigment containing ink, more preferably water-based. Said second master image is printed using a second ICC profile that is preferably specific for the printer. Preferably said second ICC profile is the same as that used to print the color patch 11 on the first substrate 10.

[0084] The printed second substrate 32 is then then dried to obtain the decorative sheet 1. In the example a hot air oven 34 is used, but alternatively other heating equipment can be used, such as microwave or infrared drying equipment.

[0085] The obtained decorative sheet 1 is then rolled up in a second roll 35.

[0086] FIG. 5 shows some steps of a method for manufacturing a laminate panel 36, as illustrated in FIG. 6, starting from the decorative sheet 1.

[0087] The laminate panel 36 at least comprise a substrate 37, for example of HDF or MDF, and a top layer 38. The top layer 38 comprises the decorative layer formed by the decorative sheet 1. In the example the decorative panel 36 is a floor panel comprising coupling means 39 on the long and short edges for coupling with adjacent floor panels in a floor covering. As illustrated in FIG. 6 such coupling means or coupling parts 39 an basically have the shape of a tongue and a groove.

[0088] In particular, FIG. 5 shows that the decorative sheet 1 is subjected to the abovementioned predetermined operation, in the example is impregnated with the melamine resin 15. Said impregnation is preferably conducted in the same way as for the first substrate and as described in FIG. 3.

[0089] FIG. 5 further illustrates that a the impregnated decorative sheet 1 is taken up in a stack to be pressed in a short daylight press 40 between upper and lower press plates 41-42. Said stack comprises from bottom to top a counter layer 43, the plate shaped substrate 37, the abovementioned impregnated decorative sheet 1 and a wear layer 44, wherein the counter layer 43 and the wear layer 44 both comprise a paper sheet 45, in case of the wear layer 44 called overlay paper, and resin 15. The stack is then pressed and the press treatment results in a mutual connection between the constituent layers 1-43-44 including the substrate 37, of the stack, as well as in a hardening or curing of the available resin 15. More particularly here a polycondensation reaction of the melamine-based resin takes place, having water as a by-product.

[0090] The upper press plate 41 is a structured press plates having a structure relief 46 that provides a relief in the melamine surface of the panel 30 during the same press treatment, by bringing the structured surface of the upper press plate 41 into contact with the melamine of the wear layer 44.

[0091] It is noted that preferably the thermal lamination step of FIG. 3 is preferably performed in the same way as described in relation to FIG. 5.

[0092] FIG. 7 shows an alternative embodiment of the invention wherein the first printed substrate 10, comprises a base sheet made of thermoplastic material, preferably PVC. FIG. 7 shows the predetermined operation that in the example involves thermal laminating, in a thermal lamination station 51, the printed substrate 10 to a transparent wear layer 50 made of thermoplastic material, preferably PVC, to form a top layer 52 for a laminate panel.

[0093] The obtained top layer 52 is subsequently attached to a substrate 53, for example made of thermoplastic material like PVC or a mineral based board, via gluing or thermal lamination.

[0094] The thermal lamination causes a color variation at the color spots 12 in the color chart 11. Although the CMYK or CRYK color coordinates of the printed color spots 12 remain the same, the visual color coordinate in the CIELAB space change. The new color coordinate can be measured with a scanner or a spectrophotometer 24 to obtain a first set of color coordinates for each color spot 12.

[0095] Said first sets of color coordinate is sent to a processing unit PU, that determines a first ICC profile that is configured simulate the visual appearance of the color chart, after the color change, on a display device 25, preferably the monitor of a personal computer.

[0096] The first ICC profile is used to visualize on said display device 25 a first master image, in the example a scanned image of a real natural wood. In this way a graphic designer can visualize on the display device 25 what will be the color change after printing and after the predetermined operation. Therefore, the operator can perform an image processing operation on said first master image while visualizing it through the first ICC profile, so that what will be the final visual result on a laminate panel can be simulated, to thereby obtaining a second master image.

[0097] Subsequently a second printable substrate 32 in the form of a thermoplastic material sheet can be uncoiled from a first roll 30 and fed to a printer 33 for printing the second master image on the second printable substrate 32. The printer 33 of the example is a single pass inkjet printer configured to print with a plurality of ink, preferably at least four inks selected from the group comprising: cyan, magenta, red, yellow, black. In this alternative example the inks are preferably pigment containing ink, more preferably UV-based or hydro-UV based, anyway it is possible that water-based inks are used. It is noted that since in this alternative example the inks are UV-based the second printable substrate 32, and preferably the first printed substrate 10, is free from an ink receiver layer, anyway it is not excluded that an ink receiver layer is used or that any other coating below or above the printed pattern is applied. Said second master image is printed using a second ICC profile that is preferably specific for the printer. Preferably said second ICC profile is the same as that used to print the color patch 11 on the first substrate 10.

[0098] The printed second substrate 32 is then subjected to UV curing, via UV lamps 55, of the inks to obtain the decorative sheet 1.

[0099] The present invention is in no way limited to the above described embodiments, but such methods, paper layers, panel may be realized according to several variants without leaving the scope of the invention.

[0100] The invention is further disclosed by the following item list as defined by the below numbered items.

[0101] 1. A method for manufacturing a decorative sheet 1 for decorative panels comprising the steps of: [0102] a) providing a first printed substrate 10 having a printed color patch 11 having at least one printed color spot 12; [0103] b) subjecting the first printed substrate 10 to at least a predetermined operation that cause a color shift of said color spot 12; [0104] c) determining a first color coordinate set for said color spot 12; [0105] d) determining a first ICC profile using said first set of color coordinate set; [0106] e) visualizing a first master image on a display device 25 using said first ICC profile; [0107] f) performing an image processing operation on said first master image to obtain a second master image during said visualization; [0108] g) printing said second master image on a second substrate 32 to obtain the decorative layer 1.

[0109] 2.The method according to item 1, wherein in that said second master image is printed using a second ICC profile, preferably a specific ICC profile of a printer 33 used for printing said second master image.

[0110] 3.The method according to item 1 or 2, wherein said step a) involves providing a first printable substrate 10 and printing said color patch 11 on said first printable substrate 10 to obtain said first printed substrate.

[0111] 4.The method according to item 3, wherein said color patch 11 is printed using a second ICC profile that is the same used to print the second master image.

[0112] 5.The method according to any of the preceding items, wherein said color patch 11 comprises multiple color spots 12.

[0113] 6.The method according to any of the preceding items, wherein said first substrate 10 and/or said second substrate 32 comprises paper layer or a thermoplastic foil.

[0114] 7.The method according to any of the preceding items, wherein said first substrate comprises an ink receiver layer.

[0115] 8.Method according to any of the preceding items wherein said predetermined operation is selected between the group comprising: impregnating, heating, pressing, gluing, covering with a transparent layer and/or laminating.

[0116] 9.Method according to any of the preceding items, wherein said printing operation is performed via inkjet printing, preferably single pass printing.

[0117] 10.Method according to any of the preceding item, wherein the second substrate 32 comprises one or more features in common with the first substrate 10, preferably said feature in common belong to the group comprising: weight, thickness, Gurley value, resin penetration time, ash content, glass transition temperature, plasticizer content, composition.

[0118] 11.Method according to any of the preceding item, wherein the second substrate 32 is the same of the first substrate 10.

[0119] 12.Method according to any of the preceding item, wherein said set of color coordinates is determined using a spectrophotometer, an optical scanner or a photographic camera.

[0120] 13.The method according any of the preceding items, wherein said first substrate 10 is subjected to multiple predetermined operation each causing a color shift, preferably steps c) and d) are performed after some, preferably each, predetermined operation and/or after one or more combination of said predetermined operations.

[0121] 14.The method according to item 13, wherein the sets of color coordinates measured after each predetermined operations are stored in a database.

[0122] 15.The method according to item 14, wherein the method involves planning one or more predetermined operation to be performed on the decorative sheet, and the step of determining the first ICC profile on the basis of said plan and of the sets of color coordinate stored in the database.

[0123] 16.The method according any of the preceding items, wherein a second color coordinate set is determined for said at least one color spot 12 before performing said predetermined operation, preferably a color shift between said first and second color coordinate set is calculated.

[0124] 17.The method according to any of the preceding items, wherein said predetermined operation is performed multiple times on multiple first substrate 10 and wherein one first set of color coordinates is determined for each first substrate 10 to obtain a plurality of sets of color coordinate for the color spot 12, and wherein said first ICC profile is determined on the basis of said plurality of sets of color coordinate.

[0125] 18.The method according to any of the preceding items, wherein said display device 25 is a screen or a monitor, preferably of a personal computer.

[0126] 19.The method according to any of the preceding items, wherein said printing operation is performed using one or more inks, preferably pigment containing inks, preferably water-based, UV-based, hydro-UV-based, oil-based or solvent-based.

[0127] 20.The method according to any of the preceding items, wherein said inks are selected from the group comprising: cyan, magenta, red, yellow, black, light cyan, light magenta, light red.

[0128] 21.The method according to any of the preceding items, wherein said first ICC profile is determined via a software, preferably ColorGate Production Server, X-Rite i1Profiler or Heidelberg Prinect Color Toolbox.

[0129] 22.Method for manufacturing decorative panels having a top layer comprising a decorative sheet 1, wherein said decorative sheet 1 is obtained in the method according to any of the preceding items.

[0130] 23.Method according to item 22, wherein it comprises the step of performing said predetermined operation on the decorative sheet.

[0131] 24.Method according to item 22 or 23, wherein the panel comprises a substrate, preferably made of MDF, HDF, thermoplastic material, mineral-based or cement-based boards.

[0132] 25.Method according to any of items from 22 to 24, comprising providing a transparent layer on top of the decorative sheet.

[0133] 26.Method according to any of items from 22 to 24, wherein said decorative panel is a floor, wall, ceiling and/or furniture panel.