EP1985464A1 - Construction plate, in particular floor panel and method for its production - Google Patents

Abstract

The panel i.e. floor panel (1), has a core (8) provided with a decoration layer (4) on a side of the core, and the decor covered with a sealing layer (5). A surface structure (6) corresponding to the decoration layer is stamped into the sealing layer, and fibers or chippings of an upper layer (3) are glued with an adhesive. The adhesive has thermoplastic characteristics, and the upper layer comprises recesses, which are molded directly below the decoration layer. The adhesive contains polyvinyl acetate dispersion, polyvinyl alcohocol and silicon-based system. An independent claim is also included for a method for manufacturing a plasterboard panel.

Description

The invention relates to a building board, in particular a floor panel, comprising a core consisting of at least one upper layer and a lower layer of glued with an adhesive and pressed together wood fibers or wood shavings core is provided on at least its upper side with a decor that with a sealing layer is covered, in which a structure corresponding to the decor is imprinted.

Such a building board is for example from the DE 102 52 863 known. Building boards with a core of wood-based material have been marketed as laminate panels for many years as a parquet substitution. In addition to mechanical and hygroscopic requirements, floor panels must also meet high demands on look and feel. The main task in this respect is to give the impression of a natural material, such as wood or stone. But fantasy decors are also used.

Therefore, generic floor panels not only have a decorative layer that may be formed as a separate printed paper layer or imprinted directly on the core of the panel, but also have a relief embossed in the surface. This surface structure may be flat and / or fine, wherein both structures may overlap. For high-quality products, they are precisely matched to the underlying decor. The expert then speaks of a decorsynchronous surface structure.

The DE 102 20 501 discloses a directly laminated plate in which a dry paper without resin impregnation is used as decorative paper and which has a high absorbency for the resin of the adhesive layer with which the decorative paper is fixed on the core. At deep embossed areas of the cover layer, the decor paper can dip into the adhesive layer without being crushed against a hard surface of the core. In this way, a gentle processing of decorative paper in the hot pressing should be possible.

The disadvantage is that such surface structures are limited in depth. Conventionally, they have a depth of about 100 microns. Deeper structures are achievable, if at all, only with increased press forces and long pressing times. Larger press forces require complex presses and reinforced tools. Long pressing times have a disadvantageous effect on the mechanical properties of the wooden-based carrier plate.

The AT 367 137 discloses a weather-resistant board made of wood fiber materials, which is characterized in that it consists of the shape and stability causing lignocellulosic fibers and / or chips and / or otherwise treated organic raw materials, binders and additives composite carrier material on the one hand and a firmly adhering outer layer from the group weather-resistant vulcanizable elastomers on the other hand, which are firmly connected to each other without additional joining of the medium mainly by mutual mechanical anchoring in the mutually facing edge zones of the carrier substance and outer coating.

Starting from this problem, the invention has the object to improve a generic building board so that it has deeper surface structures, and to provide a method for their preparation.

According to the invention, this is achieved in that the chips of the upper layer of the core are glued with an adhesive which has thermoplastic properties, and the upper layer has indentations formed at least directly under the decoration.

The composition of the adhesive for the top layer is advantageously different from the composition of the adhesive for the bottom layer. In this case, the adhesive for the upper layer has better thermoplastic properties than the adhesive for the lower layer.

• ein PF-Novolak und/oder
• eine Acrylat-Dispersion und/oder
• eine Ethylenvinylacetat-Dispersion (EVA) und/oder
• eine Polyvinylacetat-Dispersion (PVAc) und/oder
• einen Polyvinylalkohol (PVA) und/oder
• ein silanbasiertes System.

The adhesive for the upper layer preferably contains alone or in any combination:

• a PF novolac and / or
• an acrylate dispersion and / or
• an ethylene-vinyl acetate dispersion (EVA) and / or
• a polyvinyl acetate dispersion (PVAc) and / or
• a polyvinyl alcohol (PVA) and / or
• a silane-based system.

When such a core is used to make a structural panel, the increased temperature and pressure of the final compression of the backing sheet with the decor and anti-wear layer will activate the elevated thermoplastic properties of the top layer. This layer of glued wood fibers or wood shavings having an adhesive having thermoplastic properties has increased plasticity, so that post-deformation is possible. The upper layer of the core of the building board therefore forms a nachverformbare layer. Due to their increased plasticity, deep surface structures can be easily imprinted into the building board.

Preferably, the thickness of the postformable layer is about one third of the thickness of the wood material core. Since the increased plasticity of the core is needed only in the uppermost layer of the core, costs can be saved in this way.

The depth of the surface structure impressed into the surface is preferably at least partially more than 500 μm. In order to create a natural material as similar as possible impression, the relief is matched to the decor of the decorative layer.

The decorative layer may be formed as a printed paper layer, which is placed on the wood-based material core and later pressed. Advantageously, the decorative layer is formed as at least one color layer directly printed on the core. Here, both analog and digital printing methods can be used.

The decorative layer is covered with a sealing layer. It can consist of at least one layer of curable lacquer. Preferably, the sealing layer consists of at least one layer of transparent synthetic resin, for example based on UF, MF or MUF. Optionally, additives such as corundum, which increase the abrasion resistance of the resin layers, can be added to these layers.

The sealing layer may also be formed as a resin-saturated overlay. On the underside of the wood material core advantageously a return is applied. This counter-pull can be designed as a resin-impregnated paper layer. It preferably consists of at least one lacquer or resin layer applied directly to the lower parts. Its layer thicknesses are based on the order on the top of the wood core material to prevent distortion of the plate.

The inventive method for producing a building board of several layers of scattered, glued with an adhesive and compressed to a core wood fibers or wood chips provides that the wood fibers or wood chips are glued for at least the last layer with an adhesive having thermoplastic properties. Advantageously, only the wood fibers or wood chips of the last layer are glued with an adhesive having thermoplastic properties. The increased plasticity of the post-deformable layer is required in the subsequent pressing of a deep relief (surface structure) only in the uppermost layer of the core, so that production costs can be saved in this way.

Preferably, the thermoplastic adhesive is applied to the fibers or chips in addition to a thermoset adhesive. In this case, first all wood fibers or wood chips to be used in the manufacture of the building board, be glued with a thermosetting properties adhesive having before a part of these wood chips or wood fibers is branched off and additionally glued with a thermoplastic adhesive having properties. These branched wood chips or wood fibers are later sprinkled, optionally after prior dissolution, as the last layer of the spread mat formed from wood chips or wood fibers which have not been glued with an adhesive having thermoplastic properties.

Reference to a drawing, embodiments of the invention will now be explained in more detail.

Fig. 1 -

eine Draufsicht auf eine Bauplatte;

Fig. 2 -

einen Schnitt durch die Bauplatte entlang der Linie A-A in Fig. 1;

Fig. 3 -

einen vergrößerten Ausschnitt aus Fig. 2.

It shows:

Fig. 1 -

a plan view of a building board;

Fig. 2 -

a section through the building board along the line AA in Fig. 1 ;

Fig. 3 -

an enlarged section Fig. 2 ,

Building boards made of a wood material are produced by first gluing and drying wood fibers or wood chips with a conventional adhesive - which will be explained in more detail below. The thus prepared fibers or chips are scattered in several layers to a cake (mat), wherein the main direction of the fibers or chips of the individual layers intersect. This cake is, for example, endlessly scattered and fed to a continuous press in which it is then pressed under pressure and temperature to a plate in the desired strength. The thermosetting adhesive bonded to the fibers / chips cures. The so endlessly produced carrier plate is then divided and can then be further refined, for example, placed on the top of a decor and a wear protection layer and then pressed with the core (the support plate). This building board can then be further divided into furniture panels or floor panels.

The building board according to the invention, in this case a floor panel 1 consists of the core 8, the applied on the core 8 decorative layer 4, which is covered by a sealing layer 5 and the force applied to the underside of the core 8 counter-pull 7. In the sealing layer 5 is a Embossed surface structure 6, which corresponds to the decor 4 (for example, a wood grain). The core 8 consists of a lower layer 2 and an upper layer 3. The lower layer 2 consists of conventionally glued wood fibers or wood chips and the Upper layer 3 consists of wood chips or wood fibers which are glued alone or in addition with a thermoplastic adhesive.
In order to connect the panel 1 with other panels, it is provided on two sides with a groove 11 and a spring 12.

As FIG. 3 can be removed, the upper layer 3 is deformed immediately below the decorative layer 4, which was produced when embossing the surface structure 6 in the sealing layer 5 and when pressing decorative layer 4 and sealing layer 5 and return 7 to the core 8. The fact that the upper layer 3 receives the adhesive with thermoplastic properties, it is nachverformbar, so that surface structures can set 6 with a depth of more than 500 microns when embossing, without that used compared to the previous plate refinement pressing at higher pressures or longer pressing times necessary would.

UF or MUF adhesives are used as conventional adhesives for the production of fiberboard, chipboard and OSB (Oriented Standboard). In the production of particleboard and OSB, conventional adhesives continue to be MUPF and PMDI adhesives.

As another adhesive to improve the postformability either a PF novolac, an acrylate dispersion, an ethylene vinyl acetate dispersion (EVA), a polyvinyl acetate dispersion (PVAc), a polyvinyl alcohol (PVA) and / or silane-based systems is used. The aforementioned adhesives can also be combined as desired individually or in combination.

Since the additional adhesive causes additional costs, it is advantageous if the addition is limited only to that part of the core 8 which is to be deformed. This is a range of 1-2 mm, which corresponds approximately to a range of 10-30% of the plate thickness.

The production of a wood fiber board as a carrier plate (wood core material) is carried out in that during the gluing of the fibers, which are then to be scattered to the cake, a part is branched off from the actual fiber stream, the glued separately and at least as the last layer is sprinkled on a previously laid out of the actual fiber flow fiber mat as a cover layer. The wood fiber board is then produced conventionally. But it has the nachverformbare cover layer.

Notwithstanding the usual method for producing such wood fiber boards is provided after the drying of the conventionally glued fibers divert a share and gluing in another Beleimungsstation a so-called dry gluing with another adhesive. The deformable layer may be the last layer. Of course, however, it is also possible for a plurality of layers to be spread, which are additionally glued and which are to form the deformable layer, which depends on which layer thickness is desired. Since it depends on the Nachverformbarkeit of the core 8 immediately below the decorative layer 4 according to the invention, of course, the core 8 can be made entirely of wood fibers or wood chips, which are glued with an adhesive having thermoplastic properties.

When speaking of thermoplastic properties or better thermoplastic properties, it should be noted that it is not possible to make a strict distinction between a thermoset and a thermoplastic with respect to the adhesive used for gluing. The additional adhesives discussed above are thermoplastic. When used in addition to the adhesives conventionally used in gluing, better thermoplastic properties are produced. How high the thermoplastic properties must be depends on which structural depths are to be pressed or how high the degree of deformation of the core 8 should be immediately below the decorative layer 4.

LIST OF REFERENCE NUMBERS

1

floor panel

2

Lower class

3

upper layer

4

decorative layer

5

sealing layer

6

surface structure

7

return

8th

core

11

groove

12

feather

Claims (19)

Building panel, in particular floor panel, comprising a core (8) consisting of at least one upper layer (3) and a lower layer (2) of glued with an adhesive and pressed together wood fibers or wood shavings, which on at least its upper side with a decor (4) provided with a sealing layer (5), and in the sealing layer (5) a surface structure (6) corresponding to the decor (4) is embossed, characterized in that at least the fibers or shavings of the upper layer (3) are glued with an adhesive having thermoplastic properties, and the upper layer (3) at least immediately under the decor (4) molded recesses. Building board according to claim 1, characterized in that the composition of the adhesive for the upper layer (3) is different from the composition of the adhesive for the lower layer (2). Building panel according to claim 2, characterized in that the adhesive for the upper layer (3) has better thermoplastic properties than the adhesive for the lower layer (2). Building board according to one or more of claims 1 to 3, characterized in that the adhesive for the upper layer (3) contains at least alone or in any combination: a PF novolac and / or an acrylate dispersion and / or an ethylene-vinyl acetate dispersion (EVA) and / or a polyvinyl acetate dispersion (PVAc) and / or a polyvinyl alcohol (PVA) and / or - a silane-based system. Building board according to one or more of claims 1 to 4, characterized in that the thickness of the deformable layer (3) of the core (8) is about one third of the thickness of the core (8). Building panel according to one or more of the preceding claims, characterized in that the surface structure (6) at least partially has a depth of at least 500 microns. Building board according to one or more of the preceding claims, characterized in that the decor (4) is designed as a printed paper layer. Building panel according to one or more of claims 1 to 6, characterized in that the decor (4) is formed as at least one directly to the core (8) printed ink layer. Building board according to one or more of the preceding claims, characterized in that the sealing layer (5) consists of at least one curable by UV or electron beam paint layer. Building board according to one or more of claims 1 to 7, characterized in that the sealing layer (5) consists of at least one resin layer, preferably based on UF, MF, MUF. Building board according to claim 10, characterized in that the sealing layer (5) abrasion-resistant particles, such as corundum, are mixed. Building board according to one or more of claims 1 to 8, characterized in that the sealing layer (5) is formed as a resin impregnated overlay. Building panel according to one or more of the preceding claims, characterized in that on the underside of the core (8) a counter-pull (7) is applied. Building board according to claim 13, characterized in that the counter-pull (7) is formed as a resin-impregnated paper layer. Building panel according to claim 13, characterized in that the counter-pull (7) is designed as a directly applied lacquer or resin layer. A method for producing a building board of several layers of scattered, glued with an adhesive and to a core (8) pressed together wood fibers or wood chips, characterized in that the wood fibers or wood chips are glued for at least the last layer with a thermoplastic adhesive properties. A method according to claim 16, characterized in that only the wood fibers or wood chips for the last layer are glued with an adhesive having thermoplastic properties. A method according to claim 16 or 17, characterized in that the adhesive having thermoplastic properties is applied to the wood fibers or wood chips in addition to a thermosetting properties adhesive. Method according to one of claims 16 to 18, characterized in that on the upper side of the core (8) a decorative layer (4) and thereon a sealing layer and on the underside of the core (8) a counter pull (7) is applied and this structure under Pressure and temperature action is pressed, wherein in the sealing layer (5) such a deep surface structure (6) is impressed that the layer (3) deformed at least immediately under the decor (4).

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