EP1797253B1 - Lightweight structural panel and method for making same - Google Patents

Description

The invention relates to a lightweight board, their use and a method for producing the same.

Lightweight panels are used for furniture, doors, walls, and the like, because they convey a modern design and high quality with low weight. For example, the impression of a 5 cm wide, massive shelf wall can arise. From a plate thickness of about 3 cm, the following manufactured according to the prior art lightweight panels have a cost advantage over solid plates, such. As chipboard, HDF, MDF boards.

The low specific weight of the lightweight panels lowers the transport and production costs, facilitates handling during construction, allows a weaker dimensioning of the furniture because of its lower weight, allows lower-dimensioned fittings on furniture, since, for example, the doors have a lower weight cheaper, requires a lighter, less stable and thus cheaper packaging and is ultimately a buying proposition in self-furniture, as the lighter product can be better transported and built by anyone.

Known lightweight panels consist of a lightweight insert whose top and bottom is connected to a cover layer, Typical deposits are z. B. paper honeycomb or corrugated inserts and polystyrene or rigid PU foam. In the case of the insert, it is essentially important that the two cover layers are secured by the honeycombs against compression or pulling apart and displacement. These are particularly widespread in the thickness extending paper structures, eg. Tubes, honeycombs, triangles, or other structures that are particularly in the direction of Thickness resistance. The cover layers are thin plates, usually wooden materials, with a thickness of about 3 to 6 mm, the outwardly visible surface for optical reasons or to prevent penetration of dirt, moisture and the like or abrasion, either foiled, laminated, printed or painted. The edges of a lightweight board can optionally be provided with so-called bars, which are usually solid. They form the third essential element of a lightweight board and are usually used as a longitudinal and cross bar. These are mounted in the edge region instead of the insert between the cover layers or glued to the edges, forming the edges of the lightweight board, prevent foreign substances from entering the plate, give the edge stability, contribute to the bending and torsional rigidity of the plate and serve as a fixture for fasteners, z. B. to create a body element from several lightweight panels. The bars must then be integrated into the plates such that z. B. the forces occurring in the corner joint can be absorbed or the fasteners, such as screw and locknut can be sufficiently secured. Suitable materials for bars are usually solid wood, MDF, HDF, chipboard.

Lightweight panels 1, such as. In Fig. 1 and 2 are prepared according to the prior art as follows: The lower cover layer 2 forming base plate 21 is stored with the later visible surface 22 down and glued their upper surface completely. The previously tailored to measure longitudinal and transverse bars 41, 42 are placed along the side surfaces of the lower cover layer 2 on the pre-glued surface 1 1. A previously or subsequently performed provisional connection of the longitudinal and transverse bars 41,42 together, for example by brackets 43, thereby ensuring improved dimensional stability and speeds up the workflow in the subsequent handling steps. In the space between the bars then the paper honeycomb panel 3, which has the same height as the latch 4, inserted. The lower edge of the honeycomb 3 connects to the glued surface 1 2 of the lower cover layer, then the second cover layer, whose later invisible surface previously also was completely pre-glued, placed on the still open lightweight board, so that they can enter into a glue joint with the bolt and honeycomb top. Now the two cover layers of the lightweight board are pressed against each other while the glue 11,12 hardens. In order to save time and press capacity usually a variety of lightweight panels are stacked and pressed together and then harden under weighting. The time-consuming and labor-intensive production can be facilitated by the fact that inside, ie not in the area of the edges, wider bars are used, the z. B. be placed like a framework on the base plate. After curing, then obtained by sawing the large lightweight panel thus formed in the middle of the inner longitudinal or cross bar a variety of smaller lightweight panels.

The above-outlined, rather artisanal process, has several disadvantages that prevented use in mass production so far. The insertion and cutting of the bars is custom work. Because of the honeycomb structure, a large part of the glue is not used for gluing, but hardens unused on the insides of the cover layers. The slow curing process of the glue makes a continuous process impossible since the drying time is several hours. This results in further problems. To dry commercially available glues based on water, such. As urea glue and PVAC, by evaporation of moisture. This can lead to the weakening of the paper insert and top layer. The result is visible unevenness due to deformation of the insert and the cover layer itself. For this reason, a further step, namely the calibration of the finished, hardened plate is often necessary to obtain the desired flat surface.

EP-A-1 029 665 discloses a method for producing lightweight panels with a bonded at least one side with a top layer liner and glued to the top layer bars, wherein the top layer is glued to the liner and with the bars under line pressure, the line pressure is guided along the lightweight panel.

It is therefore an object of the present invention to provide an improved lightweight panel, new uses thereof, and an improved method of making the same.

This object is achieved by a method for the production of lightweight panels, a lightweight board, the use of a lightweight board and an apparatus for performing the method according to the corresponding claims. Advantageous embodiments are the subject of the dependent claims.

In the case of the method according to the invention, it is initially proposed to carry out bonding by applying line pressure between cover layer and insert and, if appropriate, the locking bar. Line pressure in the sense of the invention is merely local pressure application which moves relative to the component. Line pressure can be applied, for example, by a roller which rolls over the component. The advantage of localized pressures is that a small pressing force must be applied relative to the pressing of the entire component, since not the entire plate is simultaneously pressurized. A line pressure within the meaning of the invention can also be applied by a band guided together with the component, which for example is supported or supported by rollers on the other side. Line printing can therefore - contrary to the wording "line" - be applied in a large area. The advantage of a line pressure applied according to the invention along the lightweight panel to be formed is that it is possible to work continuously instead of at intervals. Namely, according to the prior art, it is known to press plates discontinuously under pressure or individually in stacks.

A lightweight board in the context of the invention is present when the insert of a cover layer at least stiffening material with lower specific gravity than a comparable solid plate, such as a solid wood, chip or MDF board exists. A lightweight board is already present when the top layer is attached only on one side of the insert with this, as this may already sufficient stability, ie reinforcement of the top layer is guaranteed. The invention disclosed the production of a lightweight board with an only one side glued to the top layer liner is, for example, also useful if only a Semi-finished product is produced. For example, it can then be provided that in a further step on the other side of the insert a cover layer of another material or at least with different material properties and / or material thickness is applied, said second cover layer can not be processed by the inventive method.

If the line pressure is repeatedly and temporally successively guided along the lightweight board, it is possible to apply the lightweight panel to be molded during manufacture for a long period of pressure, with each device that applies the line pressure only over in relation to the total surface of the lightweight panel low contact pressure must have. Thus, the purchase of expensive presses with high press forces can be dispensed with. The application of line pressures eg. By rolling, moreover, has the advantage that can be dispensed with a subsequent calendering of the surface of the lightweight board.

1. a) von den physikalisch abbindenden Typen z.B. Schmelzklebstoffe, weil hier schon ein blosses Anliegen der Klebflächen zum Verbund genügt und darüber hinaus ein einseitiger Auftrag des Klebstoffes ausreichend ist,
2. b) von den kalthärtenden Typen z.B. Klebelösungen als wässrige Dispersion, weil bei diesen ebenfalls ein einseitiges Aufbringen ausreicht.

This is especially true when the line or the line pressures are exercised until a complete curing of the adhesive used has occurred. The following adhesives are particularly suitable:

1. a) of the physically setting types, for example hot-melt adhesives, because here merely a concern of the adhesive surfaces for bonding is sufficient and, moreover, a one-sided application of the adhesive is sufficient,
2. b) Of the cold-curing types, for example, adhesive solutions as an aqueous dispersion, because in these also a one-sided application is sufficient.

Suitable adhesives are therefore, for example, NR (natural rubbers), glues (eg glutin glues), UF, MF, PF, RF resins, starch, dextrin, casein, PVAL, PVP, cellulose ethers and PU adhesives Curing in the context of the invention is then present if the contact pressure can be removed without significant loss of quality and further handling of the plates in production is ensured without these losing quality due to the incompletely cured adhesive. In particular, it must be ensured that the connection between top layer and insert or latch no longer triggers or the surface of the top layer can be uneven.

Endless plate in the sense of the invention means that this is in relation to the end product, i. the finished, for example, shipping and sellable lightweight panel has a greater length and the connection of the components are not intermittently, but continuously connected to each other.

Serving as a longitudinal bolt bars, which have substantially the same strength as the deposit, serve, as well as the cross bar, the stiffening of the finished lightweight panels in the edge region. If the endless plates are provided with longitudinal bars, results in a more rational production compared to the conventional manufacturing method, since the longitudinal bars do not have to be cut to plate length or their multiple. Rather, this happens in a further step, when the already finished and hardened lightweight panel is distributed, It is less work and waste to the bars.

If only longitudinal bars are used in the production of lightweight board and then a division of the endless plate is transverse to the longitudinal bars, eliminates the operation of the insertion of cross bars, depending on the application for the plate namely the separated side is not visible, eg. B. in juxtaposed or angularly joined plates,

The longitudinal bars can also be offset in the inventive method for the continuous production of lightweight panels also to the dimensions of the later separated Lightweight panels can be arranged. As a result, a special adaptation of the longitudinal bar to the later plate dimensions or their multiple, superfluous and there is no waste. Preferably, however, the adjoining longitudinal bars are provisionally, for example, interconnected by metal brackets, so that no gaps between the faces of the bars arise during subsequent compression.

Particularly efficient and according to the invention is the cutting of the endless plate, for example by sawing, in the region of the bolt, since a single bolt thus forms the edge of two adjacent after the division of lightweight panels. In this case, if necessary, the edge by the cutting in a state that requires no post-processing.

A particularly attractive and possibly injury-hazardous lightweight board is obtained when the edges and corners of the individual lightweight panels are processed to round them off, for example, or to bring in a special shape. This is done particularly efficiently if such a shape is already formed during cutting, for example by milling cutters. This eliminates the need for re-handling to edit the plate. In addition, waste may be saved if the special shapes of two adjacent lightweight panels fit together.

An alternative to the insertion of longitudinal or Querriegein is the subsequent strengthening of the edges, for example after cutting. The corresponding space can be created, for example, by compressing, mowing out or pulling the insert, which is yielding transversely to the plane of the plate, or the corresponding space is released from the outset. The room can then be filled with bars or filled with foam. Finally, it is also possible to reinforce the edges by sticking on strips, in particular those strips which have connecting means pointing into the board interior, which can connect to the insert, for example by means of barbs.

If the endless plate has at least three longitudinal bars, so when dividing the endless plate in the region of the inner longitudinal bar, the production of several parallel tracks is possible simultaneously. It is also less expensive to perform the method by means of a wide device instead of several narrow devices. For three longitudinal bars so can double production, triple at four longitudinal bars, etc.

A considerably lower adhesive consumption than in the prior art results when the adhesive is applied only where actually an adhesive contact is to be made. That the top layer is not completely blanket wetted with adhesive, but only in the area of the bar, which of course can also be caused by the fact that the adhesive is applied only to the bar. A similar predetermination results for the insert, which naturally assumes only adhesive in the area actually required for connection. An adhesive application with rollers is problematic, at least for fast-curing adhesives, since fast-curing adhesives tend to stick to the rollers after a few hours, a cleaning is necessary. The cleaning causes costs and in addition production losses. Therefore, the Aufdüsen is preferred.

In a further advantageous embodiment, it is provided that the insert is zusämmengepresst in the direction of production and is expandable. This reduces the transport, space and deployment costs. Such an expandable insert may be continuous, i. be expanded in the context of the process for the continuous production of lightweight panels, in contrast to the prior art, in which the individual insert plates must be provided and used. Examples of expandable inserts are the honeycomb panels and corrugated inserts made of paper or cardboard.

When the expandable insert is coated with adhesive prior to expansion, adhesive is initially saved over the conventional methods in which the cover layer is completely painted.

In addition, the adhesive transfer to the insert can be done particularly easily, since the compressed insert assumes the entire surface of adhesive. Therefore, rolls can be used instead of the technically complicated nozzles. The adhesive can also be applied very thick and thus penetrate deep into the material, such as cardboard, which its durability and resilience benefits. This also allows the use of papers and paperboards with a smaller cross section, which would be more problematic in the expanded state, the adoption of the adhesive on the thin web only.

In the method according to the invention, in principle, the two cover layers can be connected either successively or simultaneously with the insert or the bar. Obtaining a particularly short procedure when you naturally thereby when both cover layers, the liner and optionally the bolt are sandwiched together. Under the invention also falls when the second cover layer, which consists for example of a non-processable in the continuous process material, in another way, for. B. discontinuous, is applied. This can e.g. be the case with a lightweight panel, which should have one-sided special properties. For example, a kitchen, work or work table top whose upper cover plate consists of a strong MDF board and thus withstands attacks with a knife and a hammer. The peculiarity of such a lightweight board is that an attractive appearance (thick, high-quality wall thickness) with a low weight (insert with low specific gravity) and finally high load capacity of only one surface (MDF board) is connected.

1. a) eine randseitige Einlage, die tiefer als 5 cm, vorzugsweise 10 cm und insbesondere vorzugsweise 20 cm in die Platte hereinragt, also zu tief ist, um wirtschaftlich lediglich als Kantenverstärkung zu gelten,
2. b) eine Einlage, die selber keinen Plattenrand bildet,
3. c) eine runde Einlage, die keinen Plattenrand bildet mit einem Durchmesser von 20 cm, vorzugsweise 40 cm und insbesondere vorzugsweise 70 cm, oder
4. d) eine Einlage deren Kanten mindestens 20 cm, vorzugsweise 40 cm und insbesondere vorzugsweise 60 cm lang sind.

A similar compromise can be achieved if, in sections, the lightweight panel has a fixed insert instead of the light insert. A solid insert may be, for example, a solid chipboard, MDF, HDF board or the like. What is essential is that there is a zone of lightweight board that can withstand greater loads. For example, it is in the kitchen with kitchen plates thus conceivable to provide zones of higher load capacity in the vicinity of the stove plate. Thus, one obtains a particularly light and inexpensive plate which, however, withstands increased loads in the areas provided in front of it. It has been shown that heavy loads on the kitchen plate pile up in certain places. Of course, the reinforced zone may also be highlighted by color differences (eg, light wood / dark wood design, wood / stone design) and may be marked. The reinforced zone differs from the prior art inserted bars in that they are not substantially intended to form and reinforce the edge of the plate. and therefore z. B. is arranged in the central region of the plate and optionally framed by the bars. As a solid insert according to the invention, which differs from the known edge-side bars, the following applies:

1. a) an edge-side insert which protrudes deeper than 5 cm, preferably 10 cm and in particular preferably 20 cm into the plate, that is to deep, in order to be considered economically only as an edge reinforcement,
2. b) an insert which itself does not form a platemark,
3. c) a round insert which does not form a platemark with a diameter of 20 cm, preferably 40 cm and especially preferably 70 cm, or
4. d) an insert whose edges are at least 20 cm, preferably 40 cm and in particular preferably 60 cm long.

For design reasons, such Leichtbauküchen- or -arbeitsplatten may have the appearance and thickness of a solid plate. This can be done, for example, with veneers with / without overlay, decor papers with / without overlays, abrasion-resistant overlays and other design features, as they are known in the field of laminate flooring and furniture industry. The advantage is that z. B. of 10 m kitchen front only 2 m massive, heavy and expensive. However, the viewer gets the impression of a 10 m long, high-quality continuous worktop. According to the invention also discloses a plate in which a lightweight board with other plates (lightweight or any other plate) form a common plane and along the common side edge with this fixed or releasably connected. From the prior art, it is only known to connect lightweight panels in the region of the bars at right angles by means of known from the furniture construction fasteners (usually screw-parent compounds), which are used in the bolt.

In a further embodiment it is provided that at least one of the adjacent edges is without a bolt. As a result, the complicated provision and insertion / connection of the bolt is partially superfluous. A locking portion projecting from one of the two plates may e.g. be fitted in the bar-free edge of the adjacent plate.

Alternatively, bar-free edges may also be removed by suitable means, e.g. WoodWelding technology, which was previously used only for the rectangular joining of lightweight panels, are connected. An advantage here is an insoluble technology according to the type of one-way connection, since the fastening means in this case can be invisible in the assembled state.

If according to the invention a connection of several plates in the same plane, for example, to provide a U-shaped kitchen worktop, are provided, there are new applications for the use of lightweight panels or combinations between lightweight panels and solid panels in the field of higher loads.

According to the invention it has also been recognized that the use of lightweight panels was previously limited to furniture, doors, walls, and the like, because these are components with low local surface load. Therefore, the expert has not yet used such plates for countertops and kitchen worktops. This is However, easily possible, at least by the inventively specified plates or methods.

The above-mentioned features relating to the construction of the plates, such as e.g. asymmetric cover layers, fixed insert, etc. are also independent of the method specified in this application for the continuous production of the plates feasible.

Further advantages will become apparent from the following description. And the accompanying drawings. Likewise, according to the invention, the features mentioned above and even further can be used individually or in any desired combinations with one another. The mentioned embodiments are not exhaustive and have exemplary character.

FIG. 3 shows a lightweight panel according to the invention with the fixed deposits 91.92 93, so as to provide locally higher load capacity. The lightweight panel 1 consists of between two horizontal cover layers bordered cross bars and horizontal bars 41, 41 a and 42. These form the mechanical and optical lateral termination of the lightweight panel 1. The area covered by the bars 41, 41 a and 42 area 3 consists essentially of the honeycomb insole. This is only interrupted by fixed inserts 91, 92, 93, which form zones of higher load capacity. These deposits may for example consist of the same material as the longitudinal and transverse bars 41, 42 and naturally have the same material thickness. The lower longitudinal latch 41 a, for example, forms the front edge of a desk, for example, has a crescent-shaped, round, fixed insert 93, the user at least in the area of the table edge by the increased strength and the concomitant solid sound of the table top a conveys higher value. The insert 93 may, as in FIG. 3 shown to be formed integrally with the longitudinal bar 41 a or the corresponding edge-side bar is widened by simply what in FIG. 3 not shown. The reinforcements 91, 92, however, are independent of the bars 41, 42 in the interior of the table top. 1 inserted and define zones of higher load capacity, for example for the computer screen. It is crucial that the plate there has higher strength properties, or conveys the user a higher value by massive sound, where usually increased loads occur.

Claims (28)

1. A method for continuously manufacturing lightweight structural panels from an infinite plate comprising an inlay (3) which is glued on at least one side with a cover layer (2) and comprising rails (4) glued with the cover layer, comprising the following steps:

   - gluing the cover layer (2) with the inlay (3) and with the rails (4) under line pressure, wherein the line pressure is guided along the lightweight structural panel,

   - cutting the infinite plate into several lightweight structural panels, wherein the infinite plate is cut in the area of the rails (4) such that after the cutting one single rail forms the edge of two adjacent lightweight structural panels.
2. A method according to the preceding claim, wherein exclusively longitudinal rails will be used and the cutting will be executed transversely to the longitudinal rails.
3. A method according to one of the preceding claims, wherein the infinite plate is manufactured with at least three, preferably four longitudinal rails, which plate will be cut into several webs in the area of the inner longitudinal rails.
4. A method according to one of the preceding claims, wherein the two cover layers comprise different materials, material properties and/or material thicknesses.
5. A method according to one of the preceding claims, wherein the two cover layers comprise differing mechanical loading capacities.
6. A method according to one of the preceding claims, wherein the line pressure is guided several times in succession along the lightweight structural panel.
7. A method according to one of the preceding claims, wherein the line pressure is applied until the adhesive used for gluing is hardened, wherein in particular one of the following adhesives will be used: NR (natural rubber), glues (e.g. glutine glues), UF, MF, PF and RF resins, starch, dextrin, casein, PVAL, PVP, cellulose ether and PU adhesives.
8. A method according to one of the preceding claims, wherein a roller, a pair of rollers pushing against each other or several rollers or pairs of rollers arranged one after another are used for building up the line pressure.
9. A method according to one of the preceding claims, wherein rails serving as longitudinal rails are used, which rails are connected to the infinite plate in the longitudinal direction thereof.
10. A method according to one of the preceding claims, wherein the longitudinal rails exceed the length of the lightweight structural panel to be manufactured by means of the method.
11. A method according to one of the preceding claims, wherein the longitudinal rails are offset with respect to the length of the individual lightweight structural panels.
12. A method according to one of the preceding claims, wherein after or during the step of cutting the edges and corners of the lightweight structural panels will be shaped in a particular form.
13. A method according to one of the preceding claims, wherein after or during the step of cutting such edges will be reinforced, on which the inlay is exposed.
14. A method according to one of the preceding claims, wherein the adhesive used for gluing will be directly applied onto the rails or will be only applied on such points of the cover layer where the rails will be put on.
15. A method according to one of the preceding claims, wherein the adhesive used for gluing will be applied onto the inlay, in particular a honeycomb panel, a corrugated inlay, such that the adhesive will essentially only be present where actually a connection with the cover layer is established.
16. A method according to one of the preceding claims, wherein an expandable inlay, i.e. an inlay which is compressed at least into the direction of the manufacture, will be used, which inlay will be continuously expanded, if necessary cut to length and brought into connection with the cover layer.
17. A method according to one of the preceding claims, wherein the expandable inlay is provided with adhesive before the expansion.
18. A method according to one of the preceding claims, wherein two cover layers beneath and above the inlay and optionally the rails will be simultaneously or successively connected to the inlay or the rails.
19. A lightweight structural panel (1), manufactured according to one of the preceding claims.
20. A lightweight structural panel (1) according to claim 19, comprising cover panels (2, 5) and rails (41, 42) which are connected with an inlay (3) on both sides thereof, characterized in that
    the lightweight structural panel (1), in some sections, comprises a solid, in particular massive inlay (6) instead of the inlay (3), which inlay (6) is of such a nature that the zone formed by the solid inlay (6) can withstand higher loads.
21. A lightweight structural panel according to one of the claims 19 or 20, characterized in that the solid inlay (6) forms an edge inlay which protrudes more than 5 cm, preferably 10 cm and most preferably 20 cm into the panel.
22. A lightweight structural panel according to one of the claims 19 through 21, characterized in that the solid inlay (6) itself does not form a panel edge.
23. A lightweight structural panel according to one of the claims 19 through 22, characterized in that the solid inlay (6) forms a round inlay having a diameter of 20 cm, preferably 40 cm and most preferably 70 cm, and does not form any panel edge.
24. A lightweight structural panel according to one of the claims 19 through 23, characterized in that the edges of the solid inlay (6) are at least 20 cm, preferably 40 cm and most preferably 60 cm long.
25. A panel comprising a lightweight structural panel according to one of the claims 19 through 24, characterized in that
    the lightweight structural panel is arranged next to a second lightweight structural panel or any other panel with equal orientation and is connected to this one along the common side edge, in particular in an inseparable manner and/or by means of a one-way connection.
26. A panel comprising one or more lightweight structural panels according to one of the claims 19 through 25, characterized in that
    the lightweight structural panel is arranged next to a second lightweight structural panel or any other panel with equal orientation and is connected to this one along the common side edge, in particular in an inseparable manner, wherein at least one of the lightweight structural panels is rail-less along the side edge.
27. A utilization of a panel according to one of the claims 25 or 26 or a lightweight structural panel according to one of the claims 19 through 24 as kitchen board, work panel or worktable surface.
28. A device for carrying out the method according to one of the claims 1 through 18.

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