FLOOR BOARD AND METHOD FOR MANUFACTURING SUCH FLOOR BOARDS

Abstract

A floor board including a decorative surface layer applied to a substrate, where the substrate has MDF or HDF material at a side edge thereof, where the side edge is treated both with an impregnation agent and/or a sealing agent based on a superabsorbing material. Also a method for manufacturing such floor boards.

Claims

1. A method for manufacturing a floor board, the floor board comprising a decorative surface layer applied to a substrate, said method comprising: providing a substrate material comprising MDF/HDF material; applying a decorative surface layer to a top surface of said substrate material; dividing said substrate material into planks having approximately the size of said floor board; profiling a side edge of said planks; said MDF/HDF material being exposed at said edge; impregnating said side edge with an impregnation agent (14); wherein said method comprises a step of wetting said side edge subsequent to said profiling.

2. The method according to claim 1, wherein the step of wetting said side edge is prior to said impregnating.

3. The method according to claim 1, wherein said impregnation agent comprises a solvent, the solvent not being water.

4. The method according to claim 3, wherein the solvent is chosen from the list consisting of a butylacetate or propylacetate, such as 3-Methoxy-3-Methyl-1-Butylacetate (MMB-AC) or 1-Methoxy-Propylacetate (MPA), a dibasic ester, a glycol (di)ether, such as Dipropylene Glycol Dimethyl Ether, a benzoate ester, a diphenylmethane or dephenylethane, or a tetramethoxyether, such as Ethane,1,1,2,2-tetramethoxy.

5. The method according to claim 1, wherein said impregnation agent comprises water.

6. The method according to claim 1, wherein said MDF/HDF material comprises wax at a rate of 0.1 to 3%.

7. The method according to claim 1, wherein said MDF/HDF material comprises zones of locally lowered density at said edge.

8. The method according to claim 1, wherein the wetting is done with water or a non-water substance.

9. The method according to claim 1, wherein applying the decorative surface layer is performed using a hot press operation and wherein the board is still hot from this hot press operation upon impregnation.

10. The method according to claim 9, wherein during applying the decorative surface layer using a hot press operation, at least a melamine resin containing layer is hardened and adhered to the substrate material.

11. The method according to claim 1, wherein said side edge comprises a lowered edge surface, defined by a removed material portion of the side edge, wherein at least said lowered edge surface is treated with the impregnation agent during said impregnation.

12. The method according to claim 1, wherein said MDF or HDF material has an average density of more than 750 kg per cubic meter and comprises a higher density region at least near said decorative surface layer, wherein said higher density region has a density of 900 kilograms per cubic meter or more.

13. The method according to claim 1, wherein said decorative surface layer is formed from at least one or more paper layers; and wherein said at least one or more papers are treated with a thermosetting resin.

14. The method according to claim 1, wherein a milling machine is used for profiling the side edge of said planks, wherein the step of wetting said side edge takes place after the board has exited the milling machine.

15. The method according to claim 1, wherein a milling machine is used for profiling the side edge of said planks, wherein the milling machine comprises a transportation device, for example a chain transporting device, to transport the floor board while profiling the side edge of said planks, wherein the step of wetting said side edge takes place with the floor board being transported on said transportation device.

16. The method according to claim 15, wherein impregnating said side edge with an impregnation agent takes place with the floor board being transported on the transportation device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] With the aim of further illustrating the features of the invention, here below, by way of some non-limiting examples, some preferred embodiments are illustrated with reference to the attached drawings, wherein:

[0066] FIG. 1 gives a perspective view on a floor board in accordance with the present invention;

[0067] FIG. 2 at a larger scale shows a cross-section along line II-II illustrated in FIG. 1;

[0068] FIG. 3 at a larger scale shows a cross-section along line III-III illustrated in FIG. 1, but for a variant; and

[0069] FIGS. 4 and 5 in views similar to that of FIG. 2 illustrate further variants.

DETAILED DESCRIPTION OF THE INVENTION

[0070] FIG. 1 schematically represents a floor board 1 in accordance with the present invention. In this specific case it relates to a rectangular and oblong panel I having a first pair of opposite edges 2-3, namely the long edges, and a second pair of opposite 7e edges 4-5, namely the shott edges. Both pairs of edges 2-3, 4-5 have been provided with coupling parts 6.

[0071] FIG. 2 clearly illustrates that the coupling parts 6 at the long edges 2-3 form both a first locking system, effecting a locking in the plane of the panels 1 and perpendicularly to said edges 2-3, namely a locking in the horizontal direction R2, and a second locking system, effecting a locking perpendicularly to the plane of the panels 1, namely a locking in the vertical direction RI.

[0072] The coupling parts 6 illustrated here are basically formed as a tongue 7 and groove 8 connection, allowing for said locking in the vertical direction R1, wherein the tongue 7, respectively at least one of the groove lips 9-10, in this case only the lower groove lip 9, has been provided with additional locking elements 11-12, effecting said locking in said horizontal direction R2. The respective locking elements 11-12 are formed as an excavation at the lower side of the tongue 7, that cooperates with a protrusion at the upper surface of the lower groove lip 9.

[0073] The coupling parts 6 are of the type that allows that two of such panels 1 can be coupled to each other, upon choice, by a rotational movement W or a horizontal shifting S movement of one panel 1 in respect to the other. In this case the coupling parts 6 are realized entirely of the substrate 13, in this case being MDF/HDF material.

[0074] Preferably the coupling parts 6 in the coupled condition create a tension force pushing the coupled floor boards 1 towards each other at these edges 2-3. Although not illustrated here, this may be achieved by the lower groove lip 9 being slightly bent out of its normal relaxed unbent position, and due to its elasticity pushing on the tongue 7, at least at the location of the locking elements 10-11. Such tension force tends to close the joint at the upper edges, thereby creating a minimized risk for moisture ingress.

[0075] FIG. 2 further illustrates that both opposite side edges 2-3 are treated with an impregnation agent 14. The penetration depth D as measured perpendicularly to the profiled contour of the mechanical coupling parts 6 is larger than 0.8 millimeter, or larger than 2 millimeters along the entire contour, or always larger than 10 percent of the thickness T of the substrate 13.

[0076] Furthermore. FIG. 2 illustrates that a sealing agent 15 has been applied to one of the opposite side edges 2-3, in this case on the edge 2 which is provided with the tongue 7.

[0077] n1e panel 1 of FIG. 2 further comprises a decorative surface layer 16 comprising a print 17. A backing layer 18 or counterbalancing layer is provided at the bottom side of the substrate 13. The print 17 has been provided on a paper sheet 19, in this case, having a weight of about 60 to 80 grams per square meter, and its pattern or image represents a wood motif 20, more particularly the image of only one wooden plank. The print 17 is free from repetitions in its pattern. The decorative surface, layer 16 further comprises a wear resistant layer 21 provided over the print 17. The wear resistant layer 17 of this example comprises a paper sheet, in this case impregnated with thermosetting resin and possibly hard particles, such as aluminiumoxide. The backing layer 18 or counterbalancing layer also comprise a paper sheet 22 impregnated with thermosetting resin.

[0078] FIG. 2 makes clear that the sealing agent 15 has been applied immediately underneath the decorative surface layer 16, possibly overlapping therewith.

[0079] The floor board 1 of FIG. 1 may at the pair of short side edges 4-5 be provided with coupling parts 6 similar to the ones illustrated in FIG. 2 for the pair of long side edges 2-3.

[0080] FIG. 3 illustrates a variant wherein at the pair of short side edges 4-5 the floor board is provided with coupling parts 6 allowing for a coupling by means of a downward motion M. This is particularly interesting in combination with coupling parts 6 at the pair of long side of edges that allow for coupling by means of a turning motion, such as the coupling parts illustrated in FIG. 2. The coupling parts 6 in FIG. 3 are shaped as a male part 23 at one edge 4 and a female part 24 at the opposite edge 5. The male part 23 is formed with a downwardly extending hook shaped part 25 designed to be seated in an excavation 26 provided in a lower flank 27 of the female part 24. The hook shaped part 25 and an upwardly protruding hook shaped part 28 bordering said excavation 26 cooperate to provide a locking in a direction R2 perpendicular to the coupled edges 4-5 and in the plane of the coupled floor boards 1. A locking in a direction R1 perpendicular to said plane is provided by means of a sidewardly protruding hook 29 at the male part 23 and an undercut 30 at the female part 24. In this case the undercut 30 is formed by means of a separate insert 31 that resiliently moves inwardly and subsequently outwardly to catch the hook 29 in the undercut 30 during the downward motion M.

[0081] Such coupling parts 6 allowing for a locking by means of a downward motion M are known per se, e.g., from WO 2013/102803, WO 2006/043893, WO 01/75247, WO 03/016654 and WO 2010/087752, all incorporated herein by reference.

[0082] According to the variant illustrated in FIG. 4, the upper edge 31 of the respective opposite edges 2-3 and/or 4-5 may be formed with a lowered edge surface 32, such as in the form of a square edge or, as illustrated here in the form of a beveled, chamfered edge. Such lowered edge surface 32 may be provided with the same decorative surface layer 16 as the remainder of the upper surface of the panel 1, or, as here be provided with a separate decoration 33, or without any decoration. Such lowered edge surface 32 may be produced by pressing the respective edge down and/or, as illustrated here, by removing a material portion from this upper edge 31, thereby exposing a part of the substrate 13 and then providing the created surface with said separate decoration 33. The first technique is e.g., described in WO 2006/066776; the second technique, the result of which is illustrated here, is described in WO 01/96688. The arrows P illustrate that the impregnation agent 14 may penetrate up from a location below the lowered edge surface 32 to the MDF/HDF material behind the lowered edge surface 32 of the substrate 13.

[0083] FIG. 5 shows an embodiment wherein the superabsorbing material 15 is applied to the edges 2-3 at least at a location 34 above the center line C of the floor board 1, and at least at a location 35 below the center line C of the floor board 1. By the provision of the superabsorbing material 15 at the location 35 below the center line C of the floor board 1 the advantage is obtained that moisture raising from the underground is prevented from further entering the joint and eventually causing damage at the upper edges 31.

[0084] In the represented case the superabsorbing material 15 is in the form of particles, more particularly crystals, of SP A. The particles or crystals have an average particle size of less than 100 micron in not-swollen condition.

[0085] FIG. 5 further illustrate that the edges 2-3 may show an inclined surface 36 undercutting the respective upper edges 31, wherein this inclined surface 36 starts immediately under the decorative surface layer 16, such that in coupled condition a chamber will be formed underneath the upper edges, the chamber protruding up to or almost up to the decorative surface layer 16. Such chamber may function to accommodate the swollen crystals upon moisture ingress and will allow a sealing of the joint at a position immediately under the decorative surface layer 16. Possibly even the laterally facing side surfaces 37 of the decorative surface layer 16 adjacent to the inclined surfaces 36 may be inclined at one or both edges 2-3 in order to allow the swollen material to move up to between said laterally facing side surfaces 37.

[0086] In FIG. 5 a space 38 is created above the tongue 7 and below the decorative surface layer 16 to accommodate the superabsorbing material 15 at a location above the center line C of the floor board or panel I. Another space 38 is created above the cooperating contact surfaces 39 of the locking elements 11 and 12 to accommodate the superabsorbing material at the location 35 below the center line C of the floor panel 1. It is clear that the space 38 at location 34 may be formed in the upper groove lip 10, as well, possibly in combination with the space above the tongue 7, or not.

[0087] Similar adaptations as explained in connection to FIGS. 4 and 5 may be made at the short sides 4-5. e.g., those illustrated in FIG. 3, whether or not in combination with such adaptations being available at the long sides 2-3.

[0088] The methods of the invention are of particular interest for treatment of side edges of floor boards that comprise coupling parts 6 allowing for a locking by means of a downward motion M, since such coupling parts 6 preferably comprise a small play in the joint to allow for a smooth joining. A play of some hundredths of a millimeter'. e.g., 0.05 mm, may suffice to allow a reliable. i.e., repeatable, smooth coupling. Such play, however small it may be, may lead to increased water ingress and increased exposure of the respective edges to deterioration due to this moisture. A treatment of the edges minimizing such deterioration and the subsequent effects is hence desirable. Preferably, as said above, such coupling parts are applied at the short side edges of a floorboard. At the long edges preferably coupling parts 6 are applied that at least allow for a coupling by means of a turning motion W, such as those illustrated in FIG. 2.

[0089] Preferably the coupling parts 6 at the long side allow for attaining a coupled condition wherein a tension force is actively pushing the coupled floor boards 1 together and tending to close the long side joints. i.e., a coupled condition free from play. According to a not illustrated variant, at the long edges coupling parts 6 are applied that are basically shaped as a tongue and a groove wherein the tongue is provided with at least one snapping web at its upper surface, and wherein the groove is provided with a cooperating therewith undercut in the upper groove lip. Preferably in such case also at the underside of the tongue a snapping web is provided cooperating with a recess in the lower groove lip. Such tongue and groove arrangement is e.g., described in WO 02/059435 and may provide for a tight joint.

[0090] The invention may prove itself particularly useful as well in those cases where the decorative surface layer comprises or consists of a wood veneer with a thickness between 0.2 and 2 mm. e.g., from 0.3 to 0.8 mm. Such veneer lavers may easily discolor due to the effects of moisture ingress into the joint. Such effects may effectively be counteracted by means of the treatments of the present invention, in particularly by using the disclosed sealing agents.

[0091] With the aim of still further illustrating the features of the invention, here below, some examples and the results obtained are listed.

Example Series 1

[0092] Twelve substances were prepared in accordance with the below table.

[0093] Each of the substances was applied to the side edges of a laminate floor panel, more particularly a DPL (Direct Pressure Laminate) floor panel with similar profiles as those illustrated in FIG. 2. The entire contour of the profiled side edges was treated. The substrate material of the floor panel consisted of an 8 mm HDF material. The glue comprised in the HDF consisted of elamine-ureumfolmaldehyde (MUF). The HDF further comprised about 1% of a wax emulsion. The floor panel or floor board comprised a decorative surface layer applied to the substrate material, alike the one illustrated in FIG. 2. Said decorative surface material comprised a print provided on a paper sheet, and a wear resistant layer. A backing layer or counterbalancing layer was applied to the bottom of the substrate material. The print layer, wear resistant layer and counterbalancing layer all comprised a paper layer impregnated with thermosetting resin, namely melamineformaldehyde resin.

[0094] The obtained floor panels were joined together by means of the coupling parts available at the treated side edges, and put for 24 hours (4 hours in case of samples 2′ and 13′) in a water bath, at a temperature of 30° C. After 24 hours the weight gain of the floor panels was recorded to define the amount of water absorbed into the HDF substrate. Further the thickness of the floor panels was recorded at the treated edges to define the swelling due to the moisture absorption. The results are given in the table as a percentage value which compares to the weight and edge thickness before the water bath. It needs to be remarked that emersion of floor panels in a bath is, of course, a test condition which does not expected to occur in real life, however this test seemed suited to illustrate the beneficial effects of the treatment of the present invention.

[0095] The table also includes the results for a reference laminate floor panel having untreated

TABLE-US-00001 Impregnation Agent Solvent Sealing Agent Absorption Edge Swelling Ref. None None None 5.93% 21.67% 1 100% MDI None None 1.84% 10.1% 2 75% MDI 25% acetone None 1.17% 6.46% .sup. 2′ 75% MDI 25% acetone None N.A. 3.5% 3 73.5% MDI 24.5% acetone 2% SPA 1.23% 7.34% 4 71.5% MDI 24% acetone 4.5% SPA 1.16% 7.57% 5 75% MDI 25% ethylacetate None 1.08% 5.81% 6 75% MDI 25% MMB-AC None 1.34% 7.08% 7 75% MDI 25% dibasic esther None 1.66% 8.9% 8 75% MDI 25% glycol diether None 1.28% 6.65% 9 75% MDI 25% Rhodiasolv ® Iris None 1.81% 8.98% 10  75% MDI 25% Prifer 6813 None 1.25% 7.45% 11  75% MDI 25% tetramethoxyether None 1.15% 5.98% 12  75% MDI 25% 1-Methoxy- None 1.12% 6.89% propylacetate 13  75% MDI 25% Butyl None 1.12% 5.59% diphenyl Methane 13′  75% MDI 25% Butyl None N.A. 1.5% diphenyl Methane 14  100% fluorocopolymer None None 2.33% 14.98%

[0096] The results illustrate that treatment of the edges with a solvent comprising impregnation agent, especially MDI, leads to a tremendous increase of the water resistance of the laminate floor panels. Absorption is lowered from about 6% to less than 2%, and edge swelling is reduced from 21% to below 10%, especially in those cases where a solvent is used together with the impregnation agent.

[0097] Test results 2-2′ and 13-13′ show the positive influence of the more hydrophobic solvent Butyl diphenyl Methane on the initial performance. Edge swelling is very low in this sample after 4 hours of emersion in the water bath.

[0098] The tests are unable to demonstrate the positive influence of the sealing agent on longer standing water exposure. Since the present test conditions are concerned with soaking the coupled floor panels in a water bath, the water penetrates not only from the joint upper edges which may be sealed by the swollen crystals. At least the tests illustrate that the SP A crystals are not detrimental to the water resistance of the laminate floor panels.

Example Series 2

[0099] Ten substances were prepared in accordance with the below table.

[0100] Each of the substances was applied to the side edges of a laminate floor panel, more particularly a DPL (Direct Pressure Laminate) floor panel with similar profiles as those illustrated in FIG. 2. The entire contour of the profiled side edges was treated. The substrate material of the floor panel consisted of an 8 mm HDF material. The glue comprised in the HDF consisted of ureumformaldehyde (UF). The standard HDF further comprised about % of a wax emulsion, while the substrate used in tests 5 and 9 comprised only 0.3% of a wax emulsion. The substrate used in tests 3 and 6 were free from wax emulsion. The floor panel or floor board comprised a decorative surface layer applied to the substrate material, alike the one illustrated in FIG. 2. Said decorative surface material comprised a print provided on a paper sheet and a wear resistant layer. A backing layer or counterbalancing layer was applied to the bottom of the substrate material. The print layer, wear resistant layer and counterbalancing layer all comprised a paper layer impregnated with thermosetting resin, namely melamineformaldehyde resin.

[0101] The obtained impregnation depth of the substances was measured and recorded in the below table.

TABLE-US-00002 Impregnation Agent Solvent Substrate Penetration Depth 1 None 100% Acetone Standard MUF glued HDF 8 mm board 2 100% MDI None Standard MUF glued HDF 0.3 mm board 3 100% MDI None MUF glued HDF board, 3 mm no wax content 4 75% MDI 25% Acetone Standard MUF glued HDF 1 mm board 5 75% MDI 25% Acetone MUF glued HDF board, 2 mm reduced wax content 6 75% MDI 25% Acetone MUF glued HDF board, 6 mm no wax content 7 75% MDI 25% Acetone Standard MUF glued HDF 2 mm board, prewetting with 100% acetone 8 65% MDI 35% Acetone Standard MUF glued HDF 2 mm board 9 65% MDI 35% Acetone MUF glued HDF board, 3 mm reduced wax content 10 75% MDI 25% Butyl Standard MUF glued HDF 4 mm Diphenyl Methane board 11 100% fluorocopolymer None Standard UF glued HDF 4 mm board

[0102] The results illustrate the positive effects of solvent use, a reduced wax content or a prewetting on the attained penetration depth.

[0103] The present invention is not limited to the preferred embodiments described here above, but such floor boards and methods may be realized according to several variants, without leaving the scope of the invention. The impregnation agents and/or sealing agents disclosed in connection with the present invention, may also be used to improve the water resistance of other products based on MDF or HDF, such as floor moldings. For this reason, in accordance with a variant, the invention relates to a floor molding comprising a decorative surface layer applied to a substrate, wherein said substrate comprises MDF or HDF material, said MDF or HDF material being exposed at a surface of said floor molding, wherein said exposed material is treated with an impregnation agent and/or a sealing agent based on a superabsorbing material. It is clear that the impregnation agents and/or sealing agent named in connection with the first, second and third aspect of the invention may be used in the context of this variant. Further the method of the invention, in particular the measure to improve penetration, may be used to improve the treatment of the exposed MDF/HDF surfaces of such floor molding.