EP4010158A1

EP4010158A1 - Material board and method for producing a material board

Info

Publication number: EP4010158A1
Application number: EP20753340.7A
Authority: EP
Inventors: Michael SCHÖLER; Jörg Heinz Hüneke
Original assignee: Siempelkamp Maschinen und Anlagenbau GmbH and Co KG
Current assignee: Siempelkamp Maschinen und Anlagenbau GmbH and Co KG
Priority date: 2019-08-08
Filing date: 2020-08-05
Publication date: 2022-06-15
Also published as: CA3150406A1; WO2021023782A1; US20220355507A1; CN114206569A; CN114206569B; DE102019121471A1

Abstract

The invention relates to a material board, in particular an engineered wood board (1) comprising at least one core layer (2) made of strands (3), and outer layers (4, 5) made of chips (6), characterised in that one or both of the outer layers (4, 5) is/are designed as partial-coverage outer layers such that individual strands (3) extend at least partly through the outer layer (4, 5) up to the board surface, thereby forming interruptions in the outer layer (4, 5).

Description

Material plate and method for producing a material plate

Description:

The invention relates to a material panel, in particular a wood material panel, with at least one (inner) core layer (or middle layer) made of strands and with (outer) cover layers or outer layers made of chips. The (wood) material panel is made from a pressed material mat, which on the one hand contains the strands for the core layer and on the other hand the chips for the outer layers, using pressure and heat by pressing (in a hot press).

In the case of wood-based panels, a distinction is made in the prior art between fibreboards (e.g. MDF boards), which are made from wood fibers, and chipboards, which are made from wood chips, and OSB (Oriented Strand Board), which are made from aligned or oriented beaches. The particles are always pressed using suitable binders, with the particles generally being made available directly as glued or provided with a binder and scattered onto the respective mat, which is then placed in the press using pressure and heat is pressed.

Furthermore, multilayer wood-based panels are known from the prior art which, as hybrid panels, consist of different wood-based material particles, e.g. B. from strands as well as from chips.

Strands means in the context of the invention the strands used in principle for OSB panels, which are also referred to as coarse chips or narrow-long chips and which have a (mean) length of more than 50 mm, preferably more than 80 mm, e.g. B. 100 mm to 200 mm. The

(Average) width is more than 5 mm, preferably more than 8 mm, e.g. B. 10 mm to 50 mm. The (mean) thickness is more than 0.5 mm, e.g. B. 0.6 mm to 1.5 mm. In the context of the invention, the core layer is made from such strands.

In contrast, the cover layers, i.e. the upper cover layer and the lower cover layer, are made from (classic) chips, which have significantly smaller dimensions than the strands. They have an (average) length of less than 20 mm, preferably less than 10 mm and / or an (average) width and thickness of less than 1 mm. Such chips, which are also referred to as fine chips, are usually used for the production of classic chipboard.

The OSB panels made from strands are characterized by the use of long and slender strands and have a higher flexural strength than normal chipboard, which is also known as flat pressed panels. The disadvantage of OSB panels, however, is usually the rough surface caused by the coarse particles, which is particularly useful for subsequent surface processing, e.g. B. an application of paint is disadvantageous because the coarse structure remains visible through the coating or the application of paint.

For this reason, top layers are produced on both sides of the multilayer hybrid panels of the type described above, which do not consist of (coarse) strands but of (fine) chips (or alternatively also of fibers), so that wood-based panels with excellent optical properties are created. A disadvantage of these wood-based panels is that the strands responsible for the flexural strength are relatively far from the surface, so that the flexural strength is reduced compared to conventional OSB panels.

A multilayer wood-based panel and a method for producing such a panel, which contains one or more core layers of strands and one or more outer layers of finer particles, is e.g. B. from US 6461 743 B1 known. Papers are also processed there in order to improve the properties of the board.

From DE 1 202481 a method for the production of multilayer wood-based panels is known, which consist of a thick core layer of coarse wood particles mixed with binder and two outer, thinner cover layers, the layered arrangement being compacted under the application of pressure and heat. In this process, the core layer is embedded between two strands, which consist of a pulp of loosely felted cellulose fibers. The wooden parts of the core layer are mixed with dry, powdery binder in a manner known per se. The focus is on the production of the thin-bodied fiber suspension for the outer layers from waste paper. The core layer can be produced from veneers, which are arranged in a known manner in several layers one above the other with the fiber course essentially crossing at right angles.

A wood-based panel, in particular OSB panel with aligned narrow-long wood chips, is also known from DE 199 13589 A1. The panel consists of a sandwich construction of a middle layer and cover layers on both sides, the two cover layers being designed as at least double layers with an outer layer and an inner layer with wood chips each oriented in different directions.

In DE 102005038833 B4, an OSB panel with at least one upper cover layer, at least one middle layer and at least one

Described lower cover layer, all of which consist of resin-glued strands. In addition, a fabric layer is applied to the surface of the upper cover layer or the lower cover layer in order to increase the flexural strength.

Further examples of multilayer wood-based panels and corresponding production processes can be found in DE 102017 111 134 B4, DE 102015 120653 A1 and DE 202017 104749 U1.

Starting from the known prior art, the invention is based on the object of creating a material plate of the type described at the outset, which is characterized by a simple structure and economical production, both by high flexural rigidity and by a perfect surface finish.

To solve this problem, the invention teaches in a generic material panel of the type described at the outset that one or preferably both cover layers are designed as non-full-surface cover layers in such a way that individual strands at least partially pass through the respective cover layer with the formation of interruptions in the cover layer to the plate surface range and are thus visible.

The invention is based on the knowledge that plates such. B. made of wood-based panels with particularly high flexural rigidity or flexural strength based on OSB and consequently from strands, preferably from several layers of strands with different orientations. Furthermore, the invention is based on the knowledge that in order to improve the surface properties it is fundamentally advantageous to have such an OSB core layer or such OSB core layers on both sides with cover layers

To provide chips and especially fine chips. In doing so, however, the invention has recognized that, in order to improve the surface properties, it is not necessary to produce the cover layers from fine material in such a large thickness that the cover layers completely cover the OSB core layers. According to the invention, only very thin, not completely covering outer layers are applied to both sides of the OSB core layer, which are only intended to fill and level the gaps between the individual coarse chips that arise on the outside of the core layer or on the core layers in the course of the scattering process. On the one hand, this is advantageous because only very small amounts of chips and consequently fine material are required to level out the uneven surface of the OSB layers. Particularly advantageous, however, is the fact that the flexural rigidity of the wood-based panel, which is essentially ensured by the OSB core layer, is only insignificantly impaired, since the cover layers made of fine material are extremely thin and do not cover the entire surface. Overall, a wood-based panel is created that can be produced simply and inexpensively and yet has both excellent strength properties and a good surface quality. This makes the plate particularly suitable for further processing by z. B. coating or a paint application.

According to the invention, vegetable particles and consequently lignocellulose-containing particles, in particular from perennial plants (wood), are used as particles both for the core layer and for the cover layer. Strands made of wood or wood-based materials are particularly preferably used for the core layer. Alternatively, annual plants, e.g. B. grassy plants, straw or the like can be used. The chips for the top layers are also vegetable particles, i.e. particles containing lignocellulose. Chips are particularly preferred

Perennial plants (wood chips) used. Alternatively, chips with the specified dimensions from annual plants can also be used, e.g. B. from grassy plants, straw or the like.

To improve the mechanical properties of the plate, not only a single or homogeneous core layer of strands is preferably used, but several core layers of strands or a core layer of several layers, the strands of which are oriented in different directions, are arranged between the cover layers. In particular, three layers can be provided in the core layer, e.g. B. a middle layer and two outer layers, with the outer layers of the core layer bordered by the chip cover layers. The strands in the middle layer of the core layer are preferably oriented transversely to the longitudinal direction of the plate and consequently transversely to the direction of transport of the mat or plate during the manufacturing process. The two outer layers of the core layer are preferably oriented in the longitudinal direction and consequently along the longitudinal direction of the plate or the transport direction.

The core layer (or the plurality of core layers) can preferably (together) have a weight per unit area of more than 5 kg / m ² , e.g. B. a basis weight of 5 to 15 kg / m ² .

It is of particular importance that very thin cover layers or little cover layer material are used. So it is expedient to use cover layers (made of chips) with a weight per unit area of less than 1.5 kg / m ² , preferably less than 1 kg / m ² .

According to a further proposal of the invention, it is provided that the two cover layers (made of chips or fine chips) are different

Have basis weight, preferably the basis weight of a top layer, e.g. B. the upper cover layer is at least 10% greater than the basis weight of the other cover layer, z. B. the lower cover layer, particularly preferably at least 15% larger. The invention is based on the knowledge that, in the course of the lowering position, a multilayer mat of material to be pressed is first produced, which is then pressed in a press using pressure and heat. There is the possibility of first sprinkling the top layer material for the lower top layer on a belt conveyor in a forming station or forming line, then sprinkling the one or more core layers of strands on top of it, and then sprinkling the top layer or top layer onto this core layer or the top core layer. sprinkle the material for the upper surface layer (chip or fine chip). While the material for the lower cover layer lies flat on the belt conveyor, the material for the upper cover layer can trickle into the previously scattered core layer and consequently into the area between the strands, so that something for the upper cover layer or the upper pressed material layer to achieve optimal board properties more material is used than for the lower top layer.

The invention consequently relates not only to the material plate or wood material plate, but also to a method for felling a material plate or wood material plate, wherein a multi-layer pressed material mat with at least one (middle) core pressed material layer made of strands (or coarse chips) and a lower and an upper one Top layer of pressed material is produced from chips (or fine chips) and the multilayered pressed material mat is pressed to form the (wood) material panel with the middle layer and cover layers. The mat can be pressed in a known manner in a continuously operating press (e.g. double belt press) or alternatively in a cyclic press. Optionally, the

Surfaces of the outer layers are sanded after pressing. Of particular importance is the fact that in the wood-based panel produced in this way, the cover layers are designed as non-full-surface cover layers in such a way that individual strands at least partially extend through the cover layer to form interruptions in the cover layer and are thus visible. The strands consequently extend partially but also only partially over the entire thickness of the plate, that is to say strands are arranged at some points on the plate over the entire thickness.

There are various manufacturing options.

In a first variant of the method according to the invention, the lower and the upper top layer of pressed material are produced in such a way and consequently already set before pressing in such a way that in the course of pressing the non-full-surface top layers are created and individual strands at least partially through the top layers to form Breakthroughs in the outer layers extend to the surface and thus become visible. The structure according to the invention with the very thin and only partially provided cover layers made of fine chipboard is consequently already created during the pressing process through a corresponding design of the pressed material mat.

In a second variant of the method according to the invention, the lower and the upper top layer of pressed material are initially produced in such a way that, in the course of pressing, first full-area cover layers with a closed surface are created from cover layer chips and that then the non-full-area cover layers are created by grinding the cover layers and individual strands at least partially through the cover layers with the formation of openings in the cover layers up to the

Surface and become visible. In this alternative method of production, wood-based panels with completely closed chip surfaces are first created in an intermediate step, which, however, are then (directly) obtained by machining, e.g. B. a grinding process can be "opened" so that the wood-based panel according to the invention is available after this additional process step.

Regardless of which of the process variants is carried out, it is expedient to produce the core pressed material layer (i.e. the OSB layer or the OSB layers) in a basically known manner from scatterable or free-flowing strands by a scattering process, and that is preferred from strands that have been mixed with a common binding agent. Basically known spreading machines or spreading machine arrangements with one or more spreading heads can be used so that one or more core pressed material layers (or layers) can be produced from strands with the respectively desired orientation in a known manner. In one possible embodiment of the invention, the top layers of pressed material can also be produced from free-flowing and consequently scatterable chips by a scattering process, chips that are mixed with a binding agent preferably being used. In this respect, known spreading machines can also be used, so that, in one possible embodiment, the material for the lower cover layer is first spread on the spreading belt, then the strands for the core layer or the core layers and finally the material for the upper cover layer is spread on top then a multi-layer mat of material to be pressed is introduced into a press and pressed using pressure and heat.

In an alternative embodiment, the cover layers are not produced in the conventional way from free-flowing material by a scattering process, but are produced from a flowable, pulpy and possibly viscous chip-liquid mixture. With this variant, the cover layers can be applied particularly thinly and therefore particularly economically. In the course of the pressing process, the pulpy layer can flow and thus perfectly fill the gaps between the OSB chips and level the surfaces. This is also related to the fact that the pulp can be produced from chips of known size, but that in this consistency the chips get an even smaller dimension and are therefore even more finely distributed. In this possible embodiment of the invention, the top layers of pressed material are produced from the flowable chip-liquid mixture in the manner of a suspension which, on the one hand, contains solid particles (chips) and, on the other hand, a liquid, e.g. B. water, as also preferably contains a binder (z. B. glue). In this embodiment, a flowable mixture is used, that is, the mixture of chips and the liquid (especially water, but also glue and washing emulsions and other liquid additives) are adjusted so that the resulting viscosity of the mixture continues to flow. The proportion of the liquid in the mixture is more than 100% of the proportion of the (dry) chips, based on the weight, particularly preferably more than 200%. This means that within the mixture the liquid fraction is at least as large as the chip fraction, preferably at least 2 times (i.e. 200%), particularly preferably at least 3 times (i.e. 300%), in each case based on weight.

The flowable liquid-chip mixture can be produced in different ways. There is z. B. the possibility of producing a liquid-glue mixture and on the other hand the wood particles in a known manner in a

To reduce the mill to the desired size and then to mix the wood particles with the liquid-glue mixture, e.g. B. in a separate mixer.

Alternatively, a liquid-glue mixture can be added to the wood particles in the mill and consequently in the comminution process, so that mixing with the liquid takes place in the mill at the same time. Alternatively, the liquid, glue and wood particles can each be added separately to the mill, so that the three components are mixed in the mill to form the liquid-wood mixture.

The flowable mixture or slurry produced in this way can be processed into the sheet-like layers by various methods, e.g. B. by extrusion. In this respect, z. B. the lower layer can be extruded onto the conveyor. The OSB layer is then sprinkled on in a known manner and the upper cover layer or the material for the upper cover layer is then again extruded onto it. Alternatively, roller application can also be used.

According to the invention, it is of particular importance that basically known particles, eg. B. wood-based particles can be used, specifically for the core layer strands that are customary for OSB production. Strands means in the context of the invention long, narrow chips with a length of more than 50 mm, preferably more than 80 mm, z. B. 100 mm to 200 mm and with an average width of more than 5 mm, preferably more than 8 mm, e.g. B. 10 mm to 50 mm and with a thickness of more than 0.5 mm, e.g. B. 0.6 mm to 1.5 mm.

According to the invention, chips (for the cover layers) are understood to mean conventional chips which are significantly smaller than the strands of the core layer. Chips means wood particles with a length of less than 20 mm, preferably less than 10 mm and with an average width and an average thickness of less than 2 mm, preferably less than 1 mm. It is particularly preferred to use fine chips or chips with a size (in the dry state) which corresponds to a sieve passage of less than 2 mm, preferably less than 1 mm, particularly preferably less than 0.5 mm, for the cover layers.

Strands and shavings that are used according to the invention are produced by (mechanical) comminution from the starting product (e.g. wood) and are to be distinguished from the likewise known fibers (e.g. for MDF) which are not used according to the invention.

It is always preferred to use particles (strands and shavings) to which a binding agent has been added. Basically known binders for the production of wood-based panels can be used. So can as a binder z. B. Isocyanates or isocyanate-based are used (pMDl). Alternatively, a urea resin or a binding agent based on urea resin (UF) can be used. Phenolic glue (PF) or melamine-reinforced UF (MUF) can also be used. These can optionally be provided with phenol (MUPF, UMPF).

In the following, the invention is explained in more detail with reference to drawings, which only represent an embodiment. Show it

1 shows a wood-based panel according to the invention in a simplified vertical section,

Fig. 2 is a plan view of the surface of an inventive

Wood-based panel (detail), FIG. 3 a vertical section through a pressed material mat for the production of a panel according to the invention according to FIG. 1,

4 shows a possible system for the production of a wood-based panel according to the invention in a greatly simplified side view.

1 shows a wood-based panel 1 according to the invention in a simplified vertical section, which has a core layer 2 made of strands 3 on the one hand and an upper cover layer 4 and a lower cover layer 5 made of chips 6 on the other hand. In the exemplary embodiment shown, the core layer 2 consists of several layers 2a, 2b, 2c, each of which consists of strands 3, the strands 3 being oriented in the individual layers 2a, 2b, 2c. The figures show a possible embodiment in which the strands 3 in the middle layer 2b run transversely to the panel longitudinal direction or production direction P. The strands 3 of the upper layer 2a and the lower layer 2c are longitudinally oriented, i.e. they run with their longitudinal direction along the longitudinal direction of the panels in this production direction P. Such wood-based panels with multi-layer core layers and each upper and lower cover layer are known in principle from the prior art. According to the invention, it is provided that the strands 3 or that individual strands extend at least partially through the cover layer 4, 5 with the formation of interruptions in the respective cover layer 4, 5 to the plate surface and are thus visible. This results from a comparative consideration of Figures 1 and 2. It is indicated that the

Cover layers 4, 5 do not go through the entire surface, but that individual strands 3 protrude up to the surface, so that they are z. B. in the plan view of FIG. 2 of the cover layer 4 are directly visible. Although an upper cover layer 4 of (fine) chips 6 is consequently provided in the panel according to the invention, according to the invention this is so thin that individual strands 3 protrude to the surface and consequently through the cover layers 4, 5 and are thus visible. As a result, only very small amounts of cover layer chips 6 are used and these serve (only) to level or even out the relatively coarse surfaces of the OSB board, so that a wood-based panel 1 with a perfect surface quality is made available. It should be noted in FIG. 2 that in most cases only parts of the strands 3 can be seen in this illustration, since these strands are partly below the surface and only their ends or sections protrude up to and from the surface are visible from the surface.

Such a wood-based panel according to FIGS. 1 and 2 is produced by first producing a multi-layer pressed material mat T which has a core pressed material layer T made of strands and an upper cover press material layer 4 'made of chips and a lower cover press material layer 5' made of chips 6. Such a press mat T, which is produced on a molding belt 7, is shown in FIG. 3. This press mat T can be z. B. in a press 8 using pressure and heat to form the wood-based panel according to FIG. The figures show an embodiment in which the layers are produced during the production of the pressed material mat T in such a way that the wood-based panel 1 is created immediately in the course of pressing in the press 8, in which the strands of the core layer 2 pass through the cover layers 4, 5 reach the surface and thus become visible. In FIG. 3, a pressed material mat T is shown by way of example, in which all layers

are produced from scatterable, free-flowing pressed material, i.e. both the top pressed material layers 4, 5 ‘and the core pressed material layer 2‘ are produced or sprinkled on the forming belt 7 from chips or strands in free-flowing form with conventional spreading devices. In a basically known manner, these are particles 3, 6 which are provided with a binding agent.

In relation to FIG. 1, it has already been explained that the core layer 2 consists of several layers 2a, 2b, 2c with different beach orientations. For this purpose, according to FIG. 3, a pressed material mat 1 is produced, in which the core pressed material layer 2 ‘is again produced from several layers 2a‘, 2b ‘, 2c‘ with the corresponding orientations of the strands 3. This is also indicated in Fig. 3 by the different representation of the strands 6 in the individual layers 2a, 2b ‘, 2c‘.

In this embodiment, it is moreover expedient if chips or layers with a different surface weight are used for the two cover layers 4, 5. It is indicated in FIG. 3 that somewhat fewer chips 6 can be used for the lower cover pressed material layer 5 ′ than for the upper cover pressed material layer 4 ′. The background to this is the consideration that the lower cover pressed material layer 5 'is initially applied essentially closed and flat to the forming belt 7, while the upper cover pressed material layer 4' applied to the core layer 2 'partially trickles into the surface. This results in unequal tensile stresses in the top layers after pressing. Due to the unequal weight per unit area of the two fine chipboard cover layers, this is balanced out in the pressing process, so that a wood-based panel 1 with perfect properties is produced

As an option, there is also the possibility of not producing the top pressed material layers 4 ′, 5 ′ from conventional pourable chips, but from a flowable chip-liquid mixture 9. Such a production is shown by way of example in FIG. The plant for the production of a material panel 1, shown only in simplified form, has the already mentioned press 8 and the molding belt 7 on which the pressed material mat 1 'is produced, so that this pressed material mat 1' forms the wood-based panel 1 in the press 8 using pressure and Heat is pressed. To produce the mat 1 'to be pressed, the system has a forming station 10 which, on the one hand, has application devices 11 for the core layer and, on the other hand, application devices 12 for the cover layers. While the application devices 11 for the core layer are designed as conventional spreading machines or scattering heads for applying the strands 3, the application devices 12 for the two cover layers in this embodiment are for the aforementioned liquid application of the cover layers or for the generation of the chip-liquid mixture 9 trained. It can e.g. B. to be extrusion devices with which the chip-liquid mixture 9 is applied to form the respective cover press material layer 4 ', 5'. Thus, first of all, the lower cover pressed material layer 5 'is applied to the forming belt 7 as a chip-liquid mixture. Conventionally, the individual layers 2a, 2b, 2c of the core pressed material layer 2 'are sprinkled on it, namely with the application devices 11, with a scattering head 11 for the lower core layer and a scattering head 11 for the upper core layer and between two scattering heads 11 for the middle core position are indicated. On the scattered core pressed material layer 2 ', the upper cover pressed material layer 4' is in turn applied as a chip-liquid mixture, again with an application device 12 designed as an extrusion device.

In addition, the system only indicated in FIG. 4 can of course have further, customary components that are not shown in FIG. 4. So between the forming station 10 and the press 8 z. B. devices for processing the press mat 1 ‘, a pre-press and / or preheating device, devices for the detection of foreign bodies and / or a faulty bulk can be arranged.

Claims

Patent claims:

1. Material panel, in particular wood-based panel (1) with at least one core layer (2) made of strands (3) and with cover layers (4, 5) made of chips (6), characterized in that one or both cover layers (4, 5) as not full-surface cover layers are designed in such a way that individual strands (3) extend at least partially through the cover layer (4, 5) with the formation of interruptions in the cover layer (4, 5) to the plate surface.

2. Material panel according to claim 1, characterized in that the partial area of the beach (3) protruding through the respective cover layer (4, 5) or visible on the surface is at least 20% and preferably less than 95% of the total surface of the panel (1) is, preferably 40% to 90%.

3. Material panel according to claim 1 or 2, characterized in that between the cover layers (4, 5) at least one core layer (2) made of strands (3) is arranged, which consists of several layers (2a, 2b, 2c), preferably the strands (3) are each oriented in the individual layers of the core layer (2) and are particularly preferably oriented in different directions in individual layers of the core layer.

4. Material panel according to one of claims 1 to 3, characterized in that the cover layers (4, 5) each have a weight per unit area of less than 1.5 kg / m ² , e.g. B. less than 1.0 kg / m ² .

5. Material panel according to one of claims 1 to 4, characterized in that the proportion of the cover layers (4, 5) is less than 10%, preferably less than 8%, of the weight per unit area of the panel (1).

6. Material panel according to one of claims 1 to 5, characterized in that the two cover layers (4, 5) made of chips (6) have a different basis weight, preferably the basis weight of a cover layer, for. B. the upper cover layer (4) is at least 10% greater than the weight per unit area of the other cover layer, e.g. B. the lower cover layer (5).

7. A method for Fierstellung a material panel, in particular a wood panel (1) according to one of claims 1 to 6, wherein a multi-layer pressed material mat (1 ') with at least one core pressed material layer (2') made of strands (3) and a lower and a upper cover pressed material layer (4 ', 5') is produced from chips (6) and wherein the multi-layer pressed material mat (1 ') is pressed to form the material plate (1) with core layer (2) and cover layers (4, 5) and wherein optionally the surfaces of the cover layers (4, 5) are processed after pressing, for. B. be sanded.

8. The method according to claim 7, characterized in that the lower cover press material layer (5) and the upper cover press material layer (4 ') are produced in such a way that in the course of pressing the non-full-surface cover layers (4, 5) and individual Strands (3) extend at least partially through the cover layers (4, 5) with the formation of interruptions in the cover layer up to the plate surface and thus become visible.

9. The method according to claim 7, characterized in that the lower cover press material layer (5 ') and the upper cover press material layer (4') are produced in such a way that in the course of pressing initially full-surface cover layers with closed surfaces from top layer chips (6) and that then by a surface treatment of the top layers, z. B. by a grinding process, the non-full-surface cover layers (4, 5) are created and individual strands (3) at least partially extend through the cover layers with the formation of interruptions in the cover layers to the plate surface and thus become visible.

10. The method according to any one of claims 7 to 9, characterized in that the core pressed material layer (2 ‘) is produced from scatterable strands (3) by scattering.

11. The method according to any one of claims 7 to 10, characterized in that the cover press material layers (4 ‘, 5‘) are generated from scatterable chips (6) by scattering.

12. The method according to any one of claims 7 to 10, characterized in that the cover press material layers (4 ‘, 5‘) are generated from a flowable chip-liquid mixture.

13. The method according to claim 12, characterized in that the cover

Layers of pressed material are produced from the flowable chip-liquid mixture by extrusion or by roller application.