METHOD FOR FINISHING A WOOD BOARD

Abstract

The disclosure relates to a method for finishing a wood board with an upper face and a lower face, having the following steps: a) applying a undercoat made of a liquid melamine resin onto the upper face, the melamine resin at least partly penetrating into the upper edge layer of the wood board, b) drying the undercoat into an undercoat layer, c) applying a base color onto the undercoat layer, d) drying the base color into a base color layer, e) applying a base color onto the base color layer in order to produce a decorative element, f) drying the decorative element into a decorative layer, g) applying a liquid melamine resin onto the dried decorative layer, h) drying the melamine resin into a melamine resin layer, and i) applying a liquid medium with a proportion of isocyanate

Claims

1. A process for the finishing of a wooden board with an upper side and an underside, comprising: a) application of a basecoat made of a liquid melamine resin to the upper side, where the melamine resin penetrates at least to some extent into an upper peripheral layer of the wooden board, b) drying of the basecoat to give a basecoat layer, c) application of a base color to the basecoat layer, d) drying of the base color to give a base color layer, e) application of a printing ink to the base color layer to produce a decorative effect, f) drying of the decorative effect to give a decorative layer, g) application of a liquid melamine resin to the dried decorative layer, h) drying of the melamine resin to give a melamine resin layer, and i) application of a liquid medium having a proportion of isocyanate groups to the melamine resin layer.

2. The process as claimed in claim 1, wherein the liquid melamine resin is applied to the underside, and is dried to give a counterbalancing material.

3. The process as claimed in claim 2, wherein the liquid medium has a proportion of isocyanate groups applied to the counterbalancing material.

4. The process as claimed in claim 1, wherein the liquid medium is a dispersion which has from 50 to 60% solids content, the remainder being water, and which is dried after application to give a layer.

5. The process as claimed in claim 1, wherein the liquid medium is a molten hotmelt which solidifies after application to give a layer.

6. The process as claimed in claim 1, wherein at least one protective covering layer is applied to a dried layer of the liquid medium.

7. The process as claimed in claim 6, wherein the protective covering layer comprises nanoparticles in order to improve resistance to microscratching.

8. The process as claimed in claim 1, wherein the liquid medium comprises wear-inhibiting particles, in particular corundum particles.

9. The process as claimed in claim 1, wherein at least one of the liquid medium, the melamine resin layer, and protective covering layer comprise(s) at least one of glass beads and agents having antistatic and/or antibacterial effect.

10. The process as claimed in claim 9, wherein the diameter of the glass beads is less than 30 m.

11. The process as claimed in claim 9, wherein the diameter of the glass beads is from 30 to 120 m.

12. The process as claimed in claim 1, wherein the liquid medium is applied in a plurality of individual layers.

13. The process as claimed in claim 1, wherein the quantity applied of the liquid medium is from 50 to 200 g/m2.

14. The process as claimed in claim 1, wherein the layer structure is pressed.

15. The process as claimed in claim 14, wherein during the pressing of the layer structure a structure is embossed into the layers applied on the upper side.

16. The process as claimed in claim 4, wherein a short-cycle press is used for the pressing process.

17. The process as claimed in claim 5, wherein at least one structured roll is used for the pressing process.

18. The process as claimed in claim 15, wherein the structure is formed synchronously with respect to the decorative effect.

19. The process as claimed in claim 1, wherein the decorative effect is a decorative wood effect, decorative stone effect, decorative tile effect, or imaginative decorative effect.

Description

[0032] The invention will be described in more detail below with the aid of a drawing.

[0033] The single FIGURE shows a wooden board 1 made of HDF or MDF with an upper side O and an underside U. Liquid melamine resin is applied as basecoat to the upperside O, and penetrates at least to some extent into the upper peripheral layer of the wooden board 1. The basecoat is then dried to give a basecoat layer 2. A base color is applied to the dried basecoat layer 2, and is dried to give a base color layer 3. A printing ink is applied to the base color layer 3 to produce a decorative effect, and said ink is then dried to give a decorative layer 4. A liquid melamine resin is applied to the dried decorative layer 4, and is dried to give a melamine resin layer 5. The melamine resin can comprise glass beads 12, in particular with diameter up to 30 m, these being mixed into the liquid melamine resin.

[0034] A liquid medium which comprises a proportion of isocyanate groups is applied to the upper side O of the melamine resin layer 5. The liquid medium preferably has from 50 to 60% solids content, with water as solvent. Other materials that can also be used alongside water are organic solvents or additions, for example dispersing agents, release agents, wetting agents, and/or antifoams. Drying of the liquid medium then forms a layer.

[0035] It is also possible, instead of application of the liquid medium in the form of dispersion to the upper side O of the melamine resin layer 5, followed by active drying, to use a hotmelt (hotmelt adhesive) which has isocyanate groups. The hotmelt is heated before application and then, on cooling, spontaneously forms the layer 6. Formation of the layer can be accelerated by active cooling.

[0036] Hotmelt used can by way of example be the product marketed as PUR HC 717.5 from Kleiberit. The isocyanate groups in the hotmelt or in the (dried) dispersion are reactive, and react with the methylol group of the melamine resin to give a polyurethane, and/or with the NH group to give a urea derivative. Another possibility is the reaction with water to give amine and further reaction with free isocyanate groups to give urea derivatives. This achieves anchoring of the dried dispersion or of the hotmelt on the melamine resin layer 5. A layer is thus formed which, in comparison with a pure melamine resin layer, is softer, but nevertheless more wear-resistant, has warmer haptic properties, and produces less noise.

[0037] The medium 6 can comprise wear-inhibiting particles 8, in particular corundum particles, which can be mixed into the medium and/or scattered thereon, and also glass beads 12 with diameter from 30 to 120 m which, during the subsequent pressing process, serve as spacers between the press plate and the wear-inhibiting particles 8, in order to reduce wear on the press plate.

[0038] A protective covering layer 7 is applied to the upper side O of the solid layer 6 of medium, and can be composed of a UV lacquer which preferably comprises nanoparticles 11 based on silica in order to increase resistance to microscratching.

[0039] The protective covering layer 7 can moreover comprise agents having antistatic and/or antibacterial effect. There can also be microglass material 12 with diameter up to 30 m provided to improve surface properties.

[0040] The resultant layer structure is finallyas is knownpressed with exposure to pressure and heat to give a laminate. It is possible here that a structure corresponding to the decorative effect is embossed into the layer structure, in particular into the layer 6. If a dispersion is applied as liquid medium, it is preferable that a short-cycle press is used for the pressing process of the layer structure. If a hotmelt is used, it is preferable that a calender roll is used to press the layer structure. In the case of the short-cycle press, the structure has been engraved into the press plate, and in the case of the calender roll, it has been engraved into the circumferential surface thereof.

KEY

[0041] 1 Wooden board

[0042] 2 Basecoat layer

[0043] 3 Base color layer

[0044] 4 Decorative layer

[0045] 5 Melamine resin layer

[0046] 6 Medium/dispersion/hotmelt

[0047] 7 Protective covering layer

[0048] 8 Wear-inhibiting particles/corundum particles

[0049] 9 Counterbalancing material

[0050] 10 Medium/dispersion/hotmelt

[0051] 11 Nanoparticles

[0052] 12 Glass beads/microglass material

[0053] O Upper side

[0054] U Underside