PRODUCTION METHOD

Abstract

A method for producing a panel including a core and a decorative surface layer is disclosed. The method includes the step of applying a dry powder layer on the core. The method includes the step of applying steam on a dry powder layer on the core. Thereafter heat and pressure are applied to the powder layer in order to bond the powder together.

Claims

1-18. (canceled)

19. A method comprising: applying a dry powder layer on a core, the dry powder layer comprising a mix of wood fibers and a binder; subsequently applying steam directly onto the dry powder layer while the dry powder layer is on the core to form a stabilized powder layer on the core; and subsequently bonding the powder in the stabilized powder layer together into a cured layer by applying heat and pressure, and thereby forming a panel comprising the core and the cured layer.

20. The method as claimed in claim 19, wherein the steam is a saturated vapour consisting essentially of water.

21. The method as claimed in claim 19, wherein the steam comprises one or more additives selected from the group consisting of wetting agents, releasing agents, and colour additives.

22. The method as claimed in claim 19, wherein the core is a wood fibre based core.

23. The method as claimed in claim 19, wherein the core is an HDF panel.

24. The method as claimed in claim 19, wherein the formed panel is a building panel.

25. The method as claimed in claim 19, wherein the formed panel is a floor panel.

26. The method as claimed in claim 19, wherein the mix of the dry powder layer further comprises wear resistant particles.

27. The method as claimed in claim 19, wherein the mix of the dry powder layer further comprises aluminium oxide.

28. The method as claimed in claim 19, wherein the mix of the dry powder layer further comprises pigments.

29. The method as claimed in claim 19, wherein the mix of the dry powder layer further comprises wear resistant particles and pigments, and wherein the binder is a thermosetting resin.

30. The method as claimed in claim 19, wherein the binder is a thermosetting resin.

31. The method as claimed in claim 19, wherein a thickness of the cured layer is less than about 1 mm.

32. The method as claimed in claim 19, wherein a thickness of the cured layer is less than about 0.3 mm.

33. The method as claimed in claim 19, wherein the cured layer is a surface layer of the panel.

34. The method as claimed in claim 19, wherein the cured layer is a decorative surface layer of the panel.

35. The method as claimed in claim 19, wherein the steam is applied with a steam box.

36. The method as claimed in claim 19, wherein the dry powder layer is applied by scattering.

37. The method as claimed in claim 19, wherein heat and pressure are applied by a press.

38. The method as claimed in claim 19, wherein the press is operated with the following parameters: 8-60 seconds of pressing time; 30-60 bars of applied pressure; and 150-220 C. of pressing temperature.

39. The method as claimed in claim 19, wherein the steam is applied to the dry powder layer when the core is moving at a speed of 1 to 10 meters per minute.

40. The method as claimed in claim 19, wherein the steam is substantially uniformly applied over the dry powder layer.

41. A floor panel produced according to the method in claim 19.

42. A floor panel produced according to the method in claim 29.

43. A floor panel produced according to the method in claim 40.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The disclosure will in the following be described in connection to exemplary embodiments and in greater detail with reference to the appended exemplary drawings, wherein:

[0025] FIG. 1 Illustrates a production line and a method according to an embodiment of the disclosure;

[0026] FIGS. 2a-2b Illustrate a method for creating a design according to an embodiment of the disclosure;

[0027] FIG. 3 Illustrates a method for creating a design according to an embodiment of the disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

[0028] In FIG. 1 an embodiment of a production line is disclosed for producing a panel 5 with a decorative layer 4. A dry powder mix 2 is applied by scattering on a core 1, preferably an HDF core. The powder mix is stabilized by applying steam 3 before the powder mix is bonded together by applying heat and pressure in, for example, a press 9. If a pattern is desired, the steam may in one embodiment, be applied through a template 6, preferably rotating. In a preferred embodiment also a balancing layer 7 is applied to the core.

[0029] In the methods according to the present disclosure preferably the same scattering and pressing units as disclosed in WO2009/065769 or in WO2009/124704 are used.

[0030] In one embodiment the steam is applied by using a steam box 8, a box with one or more outlets at the bottom for steam, positioned above the transportation belt. The box preferably extends across the panel with a uniform width. An even moisture distribution is applied over the surface of the scattered powder layer 2, when the board pass under the steam box. Since the steam penetrate into the powder very effectively it is possible to immediately move the board into the press and close the press 9.

[0031] A suitable steam box is either fed by an external steam generator or the steam is generated in the steam box itself. It is suitable that that the steambox is equipped with one or several layers of nets for example mesh and/or sheets with holes to even out the steam concentration close to the powder layer.

[0032] FIGS. 2a and 2b shows how an uneven distribution of moisture 21, obtained by applying steam 3 through, e.g., a nozzle 25, can be used for design effect purpose. Different amount of moisture 21 in different parts of a single colour powder, but not yet pressed, surface gives a visual colour difference of the different parts. By controlling where on the surface the moisture content is higher a wanted design effect 22 can be generated (see FIG. 2b) in the pressed surface 24 of the panel even if only one unicolored powder layer is applied on the core 1.

[0033] By controlling the relative movement between a core 1 with the powder mix layer 2 and one or several steam outlets a controlled variation of the content of moisture 21 in the powder can be achieved. This variation of moisture content will after pressing be visible as color differences 22 on the ready surface 24.

[0034] One or several of the steam outlets could be fixed on a robot arm and their position in relation to the scattered board could then be controlled in all directions.

[0035] The steam outlets 41 could be positioned in a rotating device, preferably a steam pipe 40, to generate a controlled moisture variation 42 in the powder layer 2, see FIG. 3.

As a Non-Limiting Example, the Steps for Producing a WFF Board could be as Follows: [0036] 1) Place a balancing layer, e.g. a paper impregnated with a thermosetting resin or a mixture of wood powder and thermosetting resin is placed on a transportation belt. A typical balancing layer is two sheets of DKB 140 paper. [0037] 2) Place a wood fibre board, typically an about 10 mm thick HDF board with a density of typically about 900 kg/m3, on top of the balancing layer. [0038] 3) Moving the balancing layer and board in a speed of 1-10 m/min (a typical value is about 3 m/min) under a scattering machine were a premade mixture of wood fibres, binders, hard particles and pigments are scattered on top of the board. The powder applied can be in the range of about 100-1000 g/m2. Typical value is about 700 g/m2. [0039] 4) Moving the board, with a balancing layer on the backside and a scattered powder layer on the top side, through a steam box with even steam concentration in the speed of 1-10 m/min (typical value is about 3 m/min) where steamed water, with or without additives, penetrates into the powder and stabilize it to improve further handling and to avoid that the powder blows out when the press is closing. Typical amount of moisture applied by the steam box is 3 g/m2. [0040] 5) Bringing the board with a balancing layer on the backside and a scattered and steam stabilized powder layer on the top side into the press. [0041] 6) Closing the press, and curing the thermosetting resin in the balancing layer and the powder layer under heat and pressure. Typical press parameters are 30 seconds pressing (range is, for example, 8-60 seconds). 40 bars pressure (range is, for example, 30-60 bars) may be applied on the board. Temperature of typically about 170 degrees C. (range is, for example, 150-220 degrees C.) on the top and bottom press plates. The pressing surfaces of the press plates can be even or have structure. Structure depth typically about 0.5 mm (range for example about 0-1.5 mm)

[0042] In an alternative example also one or more paper sheets are applied after step 4.

An Example of a Production of a WFF Board with a Designed Pattern by Controlled Uneven Moisture Distribution: [0043] 1) Place a balancing layer, e.g. a paper impregnated with a thermosetting resin or a mixture of wood powder and thermosetting resin is placed on a transportation belt. A typical balancing layer is two sheets of DKB 140 paper. [0044] 2) Place a wood fibre board, typically an about 10 mm thick HDF board with a density of typically about 900 kg/m3, on top of the balancing layer. [0045] 3) Moving the balancing layer and board in a speed of about 1-10 m/min (typical value is about 3 m/min) under a scattering machine were a premade mixture of wood fibres, binders, hard particles and pigments are scattered on top of the board. The powder applied can be in the range of about 100-1000 g/m2. Typical value is about 700 g/m2. [0046] 4) Moving the board, with a balancing layer on the backside and a scattered powder layer on the top side, under one or several steam outlets that also might move sideways and open and close during the board passing time, in the speed of about 1-10 m/min (typical value is about 3 m/min) where steamed water, with or without additives, penetrates into the powder in an uneven but controlled way to obtain a variation in the moisture content in the powder layer. [0047] 5) Bringing the board with a balancing layer on the backside and a scattered and steam stabilized powder layer on the top side into the press. [0048] 6) Closing the press, and curing the thermosetting resin in the balancing layer and the powder layer under heat and pressure. The different moisture content resulting in a visible design effect in the ready pressed board. Typical press parameters are about 30 seconds pressing (range is, for example, about 8-60 seconds). About 40 bars pressure (range is, for example, 30-60 bars) may be applied on the board. Temperature of typically about 170 degrees C. (range is, for example, about 150-220 degrees C.) on the top and bottom press plates. The pressing surfaces of the press plates can be even or have structure. Structure depth typically value about 0.5 mm (range for example about 0-1.5 mm)

[0049] In an alternative example also one or more paper sheets are applied after step 4.