Digital print with water-based ink on panel surfaces
A water-based ink and a method to form a digital print with the water-based ink on a dense substrate including a polymer material or on surfaces that are heated and pressed after printing. The substrate is prior to the printing step preferably heated in order to prevent floating of the water-based ink drops.
1. A method of forming a building panel, wherein the method comprises:
heating a substrate to a temperature of at least about 80° C.;
printing a digital image with a print head by applying drops of a water-based ink on the heated substrate, wherein the water-based ink comprises a colorant comprising an aqueous pigment dispersion, a binder comprising an acrylic resin dispersion, and a viscosity increasing substance comprising glycol or glycerine;
applying a transparent wear resistant layer on the digital image; and
connecting the substrate to a core with heat and pressure, thereby forming a building panel,
wherein the substrate is connected to the core prior to the heating of the substrate to a temperature of at least about 80° C.
2. The method as claimed in claim 1 , wherein the core comprises a thermoplastic material mixed with fillers.
3. The method as claimed in claim 1 , wherein the substrate, prior to printing, is laminated with heat and pressure to the core.
4. The method as claimed in claim 1 , wherein the substrate is a thermoplastic foil or a melamine formaldehyde impregnated paper.
5. The method as claimed in claim 1 , wherein the substrate, after printing, is embossed in register with the digital image.
6. The method as claimed in claim 1 , wherein the print head is a piezoelectric print head configured to apply ink drops with a viscosity of at least about 5 cps.
7. The method as claimed in claim 1 , further comprising applying essentially dry and coloured particles on the substrate prior to the application of the water-based ink.
8. The method as claimed in claim 7 , wherein the essentially dry and coloured particles comprise a thermoplastic material.
9. The method as claimed in claim 1 , wherein the water-based ink comprises about 15-35 wt % of the aqueous pigment dispersion, and about 5-20 wt % of the acrylic resin dispersion.
10. The method as claimed in claim 1 , wherein the substrate is heated to a temperature in the range of about 80 to about 130° C.
11. The method as claimed in claim 1 , wherein the transparent wear resistant layer is a foil comprising thermoplastic material.
12. The method as claimed in claim 1 , wherein the digital image is formed by spot colours.
13. The method as claimed in claim 1 , wherein the substrate is a thermoplastic material.
14. The method as claimed in claim 13 , wherein the substrate is heated to a temperature between 90° C. and 120° C.
15. The method as claimed in claim 13 , wherein the substrate is heated to a temperature of about 110° C.
16. The method as claimed in claim 1 , wherein the drops of the water-based ink applied by the print head are sized between 5 and 20 picoliters.
17. The method as claimed in claim 1 , further comprising applying a sublayer between the core and the substrate.
18. The method as claimed in claim 16 , wherein the sublayer is a softer material than the substrate.
19. The method as claimed in claim 1 , further comprising
applying a protective layer on top of the transparent wear resistant layer, wherein the protective layer is printed directly on the transparent wear resistant layer with a digital print head, and
curing the printed protective layer at a UV curing station.
20. A method of forming a building panel, wherein the method comprises:
heating a substrate to a temperature of at least about 80° C., the substrate comprising polyvinyl chloride;
printing a digital image with a print head by applying drops of a water-based ink on the heated substrate, wherein the water-based ink comprises a colorant comprising an aqueous pigment dispersion, a binder comprising an acrylic resin dispersion, and a viscosity increasing substance comprising glycol or glycerine;
applying a transparent wear resistant layer on the digital image; and
connecting the substrate to a core with heat and pressure, thereby forming a building panel.
21. The method as claimed in claim 1 , wherein the water-based ink comprises about 45-80 wt % of the viscosity increasing substance.
22. The method as claimed in claim 20 , wherein the water-based ink comprises about 45-80 wt % of the viscosity increasing substance.