Floor panel, methods for manufacturing laminate panels and method for treating material sheets applied herewith

Abstract

Floor panel of the type substantially consisting of a substrate and a top layer provided-thereon based on synthetic material. The top layer includes a printed decor and one or more material sheets provided with synthetic material. The floor panel also includes a balancing layer at the underside of the substrate, the balancing layer containing a synthetic material layer which is free from material sheets. Methods used to make the panels are disclosed.

Claims

1. Floor panel consisting at least of a substrate and a top layer located on a first surface of the substrate; wherein said top layer comprises a printed decor and synthetic material, and wherein the floor panel is provided with a balancing layer immediately located adjacent to an underside defined as a second side of said substrate opposite the first surface, the substrate being porous and the synthetic material of the balancing layer penetrating at least partially into the substrate; wherein said balancing layer substantially consists of a synthetic material layer which is free from material sheets.

2. The floor panel of claim 1, wherein the floor panel is a laminate floor panel of the DPL type.

3. The floor panel of claim 1, wherein said substrate substantially consists of MDF or HDF.

4. The floor panel of claim 1, wherein the total weight of material sheets, which are located in the top layer, is situated between 50 and 250 g/m.sup.2.

5. The floor panel of claim 1, wherein the balancing layer is made thinner than said top layer.

6. The floor panel of claim 1, wherein the balancing layer comprises less synthetic material than said top layer.

7. The floor panel of claim 1, wherein as the synthetic material, at least one thermo-hardening resin is applied in the top layer as well as in the balancing layer.

8. The floor panel of claim 1, wherein said printed decor is provided on material sheets located in the top layer.

9. The floor panel of claim 1, wherein synthetic material of the balancing layer penetrates at least 0.1 mm into the substrate.

10. The floor panel of claim 9, wherein the synthetic material of the balancing layer penetrates at least 0.5 mm into the substrate.

11. The floor panel of claim 1, wherein the synthetic material of the top layer and the synthetic material layer of the balancing layer are made of melamine resin.

12. The floor panel of claim 11, wherein the melamine resin is a melamine formaldehyde resin.

13. Floor panel consisting at least of a substrate and a top layer located on a first surface of the substrate; wherein said top layer comprises a printed decor and synthetic material, and wherein the floor panel is provided with a balancing layer immediately located adjacent to an underside defined as a second side of said substrate opposite the first surface, the substrate being porous and the synthetic material of the balancing layer penetrating at least partially into the substrate; wherein said balancing layer substantially consists of a synthetic material layer which is free from material sheets; wherein the floor panel is a laminate floor panel of the DPL type; wherein said substrate substantially consists of MDF or HDF; wherein the total weight of material sheets, which are located in the top layer, is within the range between 50 and 250 g/m.sup.2; wherein the balancing layer is made thinner than said top layer; wherein the balancing layer comprises less synthetic material than said top layer; wherein as the synthetic material, at least one thermo-hardening resin is applied in the top layer and in the balancing layer; wherein said printed decor is provided on material sheets located in the top layer.

14. The floor panel of claim 13, wherein synthetic material of the balancing layer penetrates at least 0.1 mm into the substrate.

15. The floor panel of claim 14, wherein the synthetic material of the balancing layer penetrates at least 0.5 mm into the substrate.

16. The floor panel of claim 13, wherein the synthetic material of the top layer and the synthetic material layer of the balancing layer are made of melamine resin.

17. The floor panel of claim 16, wherein the melamine resin is a melamine formaldehyde resin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) With the intention of better showing the characteristics of the invention, hereafter, as an example without any limitative character, some preferred embodiments are described, with reference to the accompanying drawings, wherein:

(2) FIG. 1 schematically represents some steps of a method with the characteristics of the second aspect of the invention;

(3) FIG. 2 at a larger scale represents a cross-section according to the line II-II indicated in FIG. 1;

(4) FIG. 3, at a similar scale as FIG. 2, represents a cross-section according to the line III-III indicated in FIG. 1;

(5) FIG. 4, in a similar view as that of FIG. 2, represents a variant;

(6) FIG. 5, in a similar view as that of FIG. 3, represents the variant of FIG. 4;

(7) FIG. 6 represents a material sheet obtained by means of a method with the characteristics of the third aspect of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

(8) FIG. 1 represents a method for manufacturing laminate panels 1. Herein, this relates to panels 1 which are manufactured substantially by means of a DPL technique and which are of the type substantially consisting of a substrate 2, a provided-thereon top layer 3 and a balancing layer 5 located at the underside 4 of the substrate 2. For realizing the top layer 3, at least a number of material sheets 6 and the substrate 2 together are brought into a press device 7, wherein said material sheets 6 are bonded to the upper side 8 of said substrate 2 by means of a press treatment P performed by means of said press device 7.

(9) As FIG. 2 clearly shows, the material sheets 6, which are incorporated into the top layer 3, are provided with synthetic material, more particularly resin 9, in a preceding step, which is not represented here. Herein, the resin 9 is situated both in the cores of the respective material sheets 6, in this case, paper sheets, and at the surface of at least one of the flat sides, and preferably, such as here, at both flat sides of these material sheets 6. This is a consequence of the absorptiveness of the paper sheets.

(10) In the example of FIG. 2, the material sheets 6 provided with resin 9 relate to, on the one hand, an impregnated printed paper sheet which serves as the so-called decor layer 10, and, on the other hand, an overlay or protective layer 11 situated above this printed paper sheet. This overlay as such consists of an impregnated paper sheet, which becomes transparent after being pressed. The print 12 provided on the decor layer 10 may show, for example, a wood pattern.

(11) FIG. 3 clearly shows that the obtained laminate panels 1 are provided with a balancing layer 5 at the underside, which balancing layer serves for at least partially compensating a possible warping of the pressed whole. Such warping occurs because the material of the top layer 3, in particular the respective synthetic material or resin 9, and the substrate 2, for example, a substrate 2 consisting of a MDF or HDF board, react differently to the press treatment P. The top layer 3 hardens under the influence of the high press temperatures, for example, 200 C., and thereby has the tendency to shrink; the MDF or HDF substrate 2, however, hardly undergoes any dimensional deformation at such temperatures. The consequence thereof is that strong tension stresses are created in the top layer 3, which in turn may lead to warping of the substrate 2, wherein this warping is hollow at the side of the substrate 2 provided with the top layer 3. By applying a balancing layer 5, a similar tension stress can occur at the other flat side, which can at least partially compensate the tension stresses occurred in the top layer 3.

(12) The balancing layer 5 of the laminate panel 1, as represented in FIG. 3, substantially consists of a synthetic material layer 13, which is free from material sheets 6, such as paper sheets. It is clear that the laminate panel 1 represented here shows, amongst others, the characteristics of the first aspect of the invention.

(13) FIG. 1 represents that this balancing layer 5 is realized by forming, prior to said press treatment P, a synthetic material layer 13 at the underside 4 of said substrate 2. To this aim, synthetic material, more particularly resin 9, is applied on at least one flat side of the substrate 2, for example, as represented here, by means of one or more rolls 14. Optionally, a drying treatment can be performed on the applied synthetic material layer 13, such that it becomes less sticky at its surface and/or even completely looses its stickiness at this surface. Such drying treatment allows a simpler further processing of the substrate 2 provided with the synthetic material layer 13. As is also represented by the arrow 15, the side 4 of the substrate 2 which is intended for being provided with the balancing layer 5 during the application of the synthetic material layer 13, can be directed upward, and the substrate 2 with the provided-thereon and possibly at least partially dried synthetic material layer 13 can be turned, such that the side 4 with the balancing layer 5 is directed downward during the further treatments.

(14) As FIG. 2 represents, the synthetic material layer 13 possibly can penetrate up into the substrate 2, such that a good adherence is obtained between the synthetic material layer 13 and the substrate 2. This figure also shows that the synthetic material layer 13, which is provided at the underside 4 of the substrate 2, also is subjected to said press treatment P, where it then preferably hardens completely.

(15) FIG. 4 represents a case wherein at both sides of the substrate 2, prior to the press treatment P, a synthetic material layer 13 is provided, which is free from material sheets, and wherein each time a partial penetration of the synthetic material or the resin 9 into the substrate 2 is obtained. In this example, however, the decor layer 10 is not provided with resin 9. During the press treatment P, the resin 9, which is located at the decor side or upper side 8 of the substrate 2, will penetrate into the absorptive material sheet 6 of the decor layer 10, or the so-called decor paper, and in this manner cause a bond between the decor layer 10 and the substrate 2.

(16) The result of this press treatment P is represented in FIG. 5, wherein in a step subsequent to the press treatment P one or more transparent or translucent lacquer layers 16 are provided above the decor layer 10. In this manner, these lacquer layers 16 form a protective layer 11 for the print 12.

(17) FIG. 6 represents another material sheet 6, more particularly an absorptive paper sheet, which is provided with a print 12 and which is obtained by means of a method with the characteristics of, amongst others, the third aspect of the invention. Such material sheet 6 can be applied, for example, as a decor layer 10 in a laminate panel 1, such as in a laminate floor panel. The represented material sheet 6 is obtained by means of a method which comprises at least two steps. In a first step, the absorptiveness of the material sheet 6 is restricted, in that a core impregnation 17 is performed with an inferior resin 9B, such as a resin 9B comprising urea formaldehyde. In a second step, synthetic material 9A, such as melamine formaldehyde resin, was applied on both flat sides of the material sheet 6. In the figure, it is clearly shown that the resin 9A, which is provided in the second step, penetrates only over a limited distance into the paper sheet or material sheet 6, and that by means of this resin 9A substantially synthetic material layers are formed at the surface of the paper sheet.

(18) According to a not represented variant of FIG. 6, the inferior resin forms the core impregnation as well as the synthetic material layer at the surface of only one side of the material sheet, whereas the synthetic material layer at the surface of the other side consists of the better resin. In the case of a decor layer, the side with the surface layer of inferior resin preferably relates to the side averted from the print.

(19) With the intention of further illustrating the invention, here below, without any limitative character, some more exemplary embodiments are listed.

Example 1

(20) The example describes a practical embodiment of the method of the second aspect of the invention, by which in this case a panel with the characteristics of the first aspect is obtained.

(21) A HDF board is covered at both flat sides with an aqueous solution of melamine formaldehyde resin. The solution comprises 60 percent by weight solid matter of resin. The solution is applied per side with a rate of 37 g/m.sup.2. The thus treated HDF board is dried during 2 minutes at 130 C. in a hot-air oven. The surface of the deposited resin layer is no longer sticky.

(22) An untreated decor paper is put on the upper side of the board, the whole is brought into a press device which opens and closes (a so-called short-cycle press) and is pressed by means of an unstructured matte press plate during 15 seconds at a temperature of 200 C. and a pressure of 45 bar. A good adherence of the decor paper on the MDF substrate is obtained and a small, however, acceptable warping of the board can be observed. The warping is hollow at the decor side of the board, which indicates a slight insufficiency of compensating warping tendency of the balancing layer.

Example 2

(23) The same manner of proceeding is maintained as in example 1; however, now also an overlay paper provided with melamine formaldehyde resin is applied above the untreated decor paper. A similar result for adherence and warping is obtained.

Example 3

(24) The same manner of proceeding is maintained as in example 2, however, now instead of 37 g/m.sup.2 of the aqueous solution, 74 g/m.sup.2 of the aqueous solution are applied. The obtained adherence of the top layer on the substrate is good, and moreover no more warping of the pressed board is observed.

(25) In comparison, it is noted that a backing layer from the state of the art typically is provided on the basis of a 70 g/m.sup.2 paper, upon which 165 g/m.sup.2 of a 60% resin solution is applied. Therefore, it is clear that by means of the invention the material sheet, more particularly the paper, of the backing layer as well as a considerable amount of resin can be economized. Even if one proceeds as in example 2, however, wherein instead of 37 g/m.sup.2 of the aqueous solution up to 120 g/m.sup.2 are applied, still important cost savings are obtained. These higher amounts can be applied, for example, when the decor paper of the examples still is treated by also providing it with resin, more particularly impregnating it with resin.

(26) Of course, it is possible that the methods of the invention and the pertaining examples thereof are applied for manufacturing larger laminate boards, which still have to be subdivided into a plurality of smaller panels having approximately the final dimensions of the respective laminate panel to be manufactured. This possibility is preferred when the final laminate panels have a surface of less than 0.5 m.sup.2. This is the case, for example, with most laminate floor panels, wall panels and ceiling panels.

(27) It is also possible that the examples are performed by means of treated, preferably provided with synthetic material, decor papers, wherein then resin is deposited on the substrate preferably at the side of the balancing layer.

(28) The laminate panel obtained in the aforementioned example 1 can further be provided with a protective layer, such as a lacquer layer, at its decorative side or decor side. It is noted that a method wherein decor paper is not or almost not provided with synthetic material and is pressed on a substrate by means of a resin-containing intermediate layer, is known as such, for example, from EP 1 507 664. However, it has not been known yet in such method to finish the decor at least with a transparent or translucent lacquer layer, for example, with a wear-resistant lacquer, for example, corundum-containing lacquer. This may relate to an UV-hardening or electron beam-hardening lacquer. Possibly, several lacquer layers may be used, or one or more other intermediate layers, such as layers consisting of melt glue. Preferably however, the upper finishing layer consists of said transparent or translucent lacquer layer, which possibly is made wear-resistant or scratch-resistant. A method in which such finishing is applied by means of an untreated or almost untreated decor paper, which is pressed by means of a resin-containing intermediate layer, as such forms an independent aspect of the invention. This independent fourth aspect of the invention may also be described as a method for manufacturing laminate panels of the type consisting at least, however, preferably substantially, of a substrate and a provided-thereon top layer, wherein the method comprises at least the steps of: providing a synthetic material-containing layer on the substrate, wherein this synthetic material-containing layer preferably is free from material sheets; providing on said synthetic material-containing layer a, preferably absorptive, material sheet showing a printed decor; performing, in a press device, a press treatment at least on the substrate, the synthetic material-containing layer and the absorptive material sheet such, that these are bonded to each other;
characterized in that above the printed decor, one or more transparent or translucent layers are provided, preferably after said press treatment is performed. It is clear that as the synthetic material, the synthetic materials applied in the remaining aspects can be used, and that as lacquers the also above-mentioned wear-resistant UV- or electron beam-hardening lacquers can be applied. As the material sheet, preferably a printed paper sheet is applied. It is also noted that providing the lacquer layer can also be performed after the pressed whole has been divided into smaller panels.

(29) For providing the synthetic material layers at the underside and/or the upper side of the substrates, any technique can be applied. Preferably, however, no carrier sheet is used during this application process. For example, roller devices and/or spraying devices and/or atomization devices and/or pouring curtains and/or spreading devices can be used, which provide the synthetic material directly on the substrate. Preferably, the respective synthetic material layer is provided in a dosed manner. Possibly, dosing may be performed by removing an excessive amount of synthetic material after application. When using hardening agents, preferably a separate application system is used for the hardening agent, and/or a mixing device, which, for example, is situated close to the application system, such that the risk that the synthetic material hardens on or in the application system is minimized and/or the lifetime of the synthetic material is extended.

(30) It is clear that the FIGS. 4 and 5 of the detailed description also illustrate some steps in a method with the characteristics of the herein above-mentioned fourth aspect of the invention.

(31) It is noted that according to the first and the second aspect of the invention the balancing layer is free from material sheets and that therefore, it is thus not excluded that at the underside of the substrate, at the one or the other side of the synthetic material forming the actual balancing layer, also one or more material sheets are present, which, however, have no appreciable balancing effect. For example, a cardboard layer may be present at the underside of the panel, which has a certain noise-absorbing effect. Preferably, however, the underside of the substrate is free from such material sheets, more particularly paper layers.

(32) It is noted that the methods of the present invention are intended in particular for manufacturing laminate floor panels, or material sheets which can be applied when manufacturing such floor panels. Preferably, this relates to laminate floor panels manufactured by means of a DPL technique. Further, it is noted that the invention also relates to the products which are obtained or can be obtained by means of a method with the characteristics of one or more of the aforementioned aspects.

(33) Further, it is also noted that the herein above-mentioned balancing layers, instead of consisting substantially of resin, for example, also may consist substantially of a noise-absorbing synthetic material layer, such as a polyurethane-containing synthetic material layer. Applying a polyurethane-containing material for realizing a synthetic material layer at the underside of a coated panel as such forms an independent fifth aspect of the present invention, independently of the fact whether this synthetic material layer has any balancing effect or is or is not free from material sheets. To this aim, the invention relates to a floor panel of the type consisting at least of a substrate and a provided-thereon top layer with a printed decor, wherein the floor panel, at the underside of said substrate, is provided with a backing layer, with the characteristic that said backing layer comprises polyurethane. Preferably, the floor panel of the fifth aspect relates to a floor panel with a printed decor which is obtained by performing a print directly on the panel, such as a print obtained by means of a digital printing technique, for example, inkjet printing, wherein this print is performed on one or more primer layers already present on the substrate, wherein the obtained print preferably is finished further by means of one or more transparent or translucent finishing layers. Preferably, for the finishing layers at least one lacquer layer is applied, such as a UV-hardening or electron beam-hardening lacquer layer. Preferably, for the backing layer also a lacquer layer is applied, wherein this lacquer layer then comprises polyurethane. Preferably, said polyurethane-containing material is provided on the underside of the substrate in liquid form, wherein it then foams or is foamed up. Preferably, foaming takes places in a controlled manner, for example, in a mold or in a press device.

(34) The present invention is in no way restricted to the herein above-described embodiments; on the contrary may such floor panels and methods be realized according to various variants, without leaving the scope of the present invention.