ES2992159T3 - Board-shaped material and method for its manufacture - Google Patents

Abstract

The invention relates to a method for producing a slab-shaped material comprising lignocellulosic fibers and binders and fillers. To provide a slab-shaped material that exhibits reduced swelling when using fibers, it is envisaged that the proportion of binder and filler, as well as an optionally used elasticizing additive, exceeds 50% by weight of the slab-shaped material. The invention further comprises a method for producing the slab-shaped material. (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Board-shaped material and method for its manufacture

The invention relates to a board-shaped material and a method for its manufacture, as well as to the use of the board-shaped material.

Board-shaped materials made from lignocellulosic fibres are used in a wide variety of applications because they are cheap to manufacture and are carried out using a well-developed technique. Typically, high-density fibreboard (HDF) is used, for example, where wood fibres are pressed into boards using binding agents, which are then usually coated. In the presence of water, the wood fibres at the exposed edges begin to swell as a result of water absorption, causing a change in the shape of the wood-based board. The water can be free-flowing water or abundant moisture. However, the swelling cannot be completely reversed, so that after the initial swelling, an unsightly open slot remains. Board-like materials made from lignocellulosic fibres are described in WO 2016/071007 A1, WO 2011/107900 A1, DE 102007 041 438 A1, US 2017/190156 A1 and US 2008/0234423 A1.

The invention aims at providing a board-shaped material and a method for its manufacture, which exhibits reduced swelling using fibers.

This objective is solved by a method according to claim 1 and a wood-derived material in the form of a board according to claim 8. The use of the board-shaped material according to the invention is set out in claim 15.

The invention relates to a board-like material comprising fibres, binder and filler and, optionally, an elastifying additive, wherein the proportion of the binder and filler and of the optional elastifying additive, based on the board-like material, is greater than 50% by weight. Fibres within the meaning of the present invention are solid particles which are elongated, i.e. having a diameter which is many times smaller than the longest dimension of the particle. The diameter of the fibres is between 10 µm and 5 mm, and their length is between 0.05 mm and 100 mm.

The board-shaped material therefore has a higher proportion of binder and filler and optionally of elastifying additive than fibres. The proportion of binder or filler and also the proportion of the optionally added elastifying additive can also be expressed on a fibre basis, i.e. the proportion of binder is specified with reference to the weight of the fibres used. In the case of hygroscopic fibres that can absorb moisture (e.g. lignocellulosic fibres), the fibre proportion is specified as fibres dried to constant weight, typically fibres dried to constant weight at 105 °C (fibrasatro:fully dried fibres). Thus, the binder proportion of the board-shaped material is higher than 100% by weight based on the fibre proportion. The binder with the filler, optionally supplemented by the elastifying additive, forms the major proportion of the board-shaped material according to the invention, usually the predominant proportion of the material according to the invention. Preferably, the board-shaped material has more than 100% by weight, for example 101% by weight or 102% by weight, up to 120% by weight of binder and filler, based on the fibre proportion; advantageously, the material has more than 150% by weight of binder and filler, even more preferably more than 200% by weight of binder and filler, at most 500% by weight of binder and filler, in each case based on the fibre proportion.

Organic or inorganic fibres can be used for the board-shaped material according to the invention. Natural fibres, for example lignocellulosic fibres, cotton or linen fibres, or synthetic fibres such as fibres made of thermoplastic material such as polyethylene or polypropylene, but also polycarbonate, polyacrylate, polymethacrylate or polyurethane, can be used to produce the material according to the invention. Inorganic fibres, such as carbon fibres or fibres made from mineral or ceramic raw materials, or glass fibres, are particularly suitable for producing the board-shaped material when mixed with other fibres. In particular, fibre mixtures, in particular mixtures of the fibres mentioned, can be used to produce the material according to the invention. Fibre mixtures make it possible to adjust the properties of the material according to the invention, for example elasticity or bending properties, dimensional stability, strength, and furthermore manufacturing properties or processability. If fibres from renewable raw materials are used, in particular lignocellulosic fibres, for example wood fibres, bamboo or annual plants, then inexpensive and easy-to-process fibres are available. Natural fibres are preferably used untreated, i.e. the properties of the fibre components cellulose and lignin and, where appropriate, hemicelluloses are not altered by chemical processes. The use of hygroscopic fibres is not excluded, especially if these are at least partially dried before producing or pressing the material according to the invention.

According to the invention, the lignocellulosic fibres mentioned above comprise all fibres obtained from plants by chemical or physical processes. Common examples of fibres obtained by physical methods are softwood fibres, hardwood fibres or bamboo fibres, or fibres from other organic raw materials obtained by mechanical defibre removal. An example of fibres produced by chemical methods are cellulose fibres made from wood, annual plants or other raw materials, in particular renewable raw materials. Blends of fibres can also be used, in particular to adjust the material properties (strength properties, weight), but also to use the fibre from the raw material in a cost-optimised manner. Fibres in the sense of this invention are also fibre bundles; smaller chips are also included, provided that their fibres can still be largely coated with binder.

The material according to the invention is board-shaped, i.e. it generally has two main surfaces, which will also be referred to hereinafter as top and bottom. Narrow surfaces or edges of the material are arranged between the top and the bottom. According to the invention, the thickness of the finished board-shaped material may be between 3 mm and 500 mm, typically between 3 mm and 80 mm, typically between 3 mm and 30 mm. A common application may require a thickness of the board-shaped material of 4 mm to 14 mm, in particular between 4 mm and 7 mm. The material according to the invention may have flat main surfaces, but the top and/or bottom may also be embossed or milled or otherwise machined, so that a variable thickness of the material is obtained in relation to the surface of the material. Preferably, the material has a practically homogeneous composition throughout the thickness. The edges, with a height corresponding to the thickness of the material, can be machined with standard tools. They can be sawn, cut or milled. The maximum length and width of the board-shaped material according to the invention are limited only by the available presses used to manufacture the material. Smaller dimensions can be manufactured by cutting the board-shaped material. Common dimensions of the board-shaped material can be 5600 mm (length) x 2070 mm (width) after manufacturing in the press, 1380 mm x 195 mm, after division into floor, wall or ceiling panels, or 3048 mm * 2800 mm. The latter format is particularly suitable for use in construction, because the width of the board is the height of the floor.

The board-shaped material according to the invention can be used in various ways. It can be used, for example, as floor, ceiling and/or wall covering, for the production of interior fittings or furniture, in particular also for the fitting out of vehicle interiors, such as vehicle cabins, but also outdoors, both as a covering, for example as a ventilated façade, and for structural applications. The board-shaped material according to the invention can be coated, coloured, painted or otherwise decoratively designed. In particular, surface coatings, such as those known in the field of wood-based materials, for example a coating with synthetic resin-impregnated paper, a PVC coating, a wood veneer, a paint or a coating with thermoplastics, can be applied to the surface of the material according to the invention. Furthermore, the board-shaped material according to the invention can be used as a component of a sandwich board, i.e. the material according to the invention is combined with the same or other sheet or board-shaped materials, in particular wood-based boards, but also plastic boards or sheets, to form a sandwich board.

The density of the material according to the invention is between 1000 kg/m3 and 1800 kg/m3, in particular between 1000 kg/m3 and 1600 kg/m3, advantageously between 1000 kg/m3 and 1300 kg/m3, particularly advantageously between 1030 kg/m3 and 1200 kg/m3. Due to the high use of binder and filler, the material according to the invention has a higher weight, for example between 1000 kg/m3 and 1200 kg/m3, compared to a wood-based material, for example an HDF board, which predominantly contains, in terms of quantity, lignocellulosic fibres.

The material according to the invention differs from the WPC described above in that it is not plastic, in particular thermoplastic plastic, which is formed with fibres to give a board-like material, but a binder is used which interacts cohesively and/or adhesively with the fibres. Such binders are known, for example, from the production of wood-based materials from the prior art. The binder used according to the invention preferably comprises melamine. Melamine is used in aqueous solution, for example as melamine-formaldehyde resin (MF resin), whereby the solids content of the melamine-containing resin is preferably at least 45% by weight based on the aqueous solution, advantageously the solids content is greater than 50% by weight. The upper limit of the solids content is determined by the solubility and, where appropriate, the processability of the melamine, for example in spray nozzles. Melamine-containing resin is preferred as a binder because it does not swell and is not hygroscopic, as well as being resistant to hydrolysis. A melamine-containing resin can be used alone as a binder or in combination with one or more binders. In the context of the present invention, in combination means that mixtures of binders can be used, whereby the mixture of two or more binders is applied to the fibre simultaneously. Or a combination of binders is used, which are applied one after the other, for example, because they cannot be used mixed or because the application of different binders separately has an advantageous effect. In combination with the above-mentioned melamine-containing resin, in particular MF resin, or alternatively, other binders such as methylenediphenyl isocyanate (MDI), also in emulsified form as eMDI or polymeric diphenylmethane diisocyanate (PMDI), and also polyurethane can be used. Although phenolic resin is impermeable, it is dark in colour, which is a disadvantage in its application. As described above, two or more binders can also be used in combination. It is preferred that the binder predominantly contains melamine. Also, the proportion of melamine-containing resin in the binder preferably exceeds 20% by weight, in particular 50% by weight. The binder preferably does not contain urea, since urea contributes to the hygroscopicity and thus to the swelling of the lignocellulosic fibres or does not prevent it. Thermoplastic binders are advantageously avoided, in particular the exclusive use of thermoplastic resins is avoided, preferably excluded. The board-shaped material according to the invention is preferably free of halogens (e.g. fluorine, chlorine), but also of terephthalates.

The material according to the invention contains filler. The filler replaces the binder. The proportion of binder and filler is therefore greater than 50% by weight relative to the board-shaped material. The proportion of filler can be from 1% by weight to 30% by weight, in each case based on the board-shaped material. Preferably, a non-hygroscopic filler is used, in particular kaolin (hydrated aluminium silicate). Other fillers according to the invention, as an alternative or in admixture with kaolin, are:

• carbonates, such as magnesium carbonate or calcium carbonate (CaCO3 or chalk),

• metal oxides such as titanium dioxide and/or aluminium trioxide,

• metal hydroxides such as aluminium trihydroxide,

• other silicates such as hydrated magnesium silicate (Mg3[(OH)2|Si4O-i0] or talc)

• other metallic salts such as calcium sulphate dihydrate (Ca[SO4]2H2O or gypsum spar or, abbreviated, gypsum) or barium sulphate (BaSO4 or barite).

The filler is used in the form of particles with a size of 0.1 µm to 50 µm. The binder and the filler can be added separately to the fibers. According to an advantageous embodiment, the binder and the filler are mixed before being added to the fibers.

Preferably, the material comprises additives. The additives may help to optimise the weight of the board-shaped material, usually to minimise it or to further improve the structure of the binder, filler and fibre matrix. An additive or a combination of additives may be used alternatively or additionally to optimise certain properties of the boards, for example conductivity, insulating properties or strength properties. An additive replaces fibres in the material according to the invention. Since the material should exhibit minimal swelling in the presence of water, in particular minimal thickness swelling, non-hygroscopic or non-swelling additives and hydrolysis-resistant additives are preferred. Such additives may be ceramic, synthetic or glass particles. The particle size is preferably not larger than one millimetre, preferably between 10 µm and 800 µm. Mixtures of different particles may also be used, for example mixtures of different materials or sizes. Up to 30% by weight of the total weight of the board-shaped material is used, even more preferably up to 20% by weight, advantageously up to 15% by weight. The lower limit of the application rate results from the detectability of an additive. The additive can be applied to the fibres before or after applying the binder and filler, preferably by spraying.

In an advantageous embodiment, the elastic properties of the board-shaped material can be modified, in particular improved, by adding an elastomer or thermoplastic which is used as an elasticizing additive, for example by adding polyvinyl acetate (PVAc) or ethyl vinyl acetate. Acrylate, styrene acrylate or polyurethane (PU) are preferably used for the elasticity of the board-shaped material according to the invention, for example in the form of a liquid additive such as a dispersion, because they are water-resistant. Acrylate, styrene acrylate and PU with a glass transition temperature of TG below 0 °C are preferred. However, monoethylene glycol or diethylene glycol are also suitable for the elasticity of the board-shaped material. The mentioned elasticizing additives can be used alone or in mixtures. The addition of elastomers or thermoplastics reduces the brittleness of the board-shaped material and improves the elastic properties of the board-shaped material according to the invention, for example the modulus of elasticity. The addition of elasticizing additives also improves the flatness of the board-shaped material. The elasticizing additive, calculated as solids, is used in proportion to the amount of solids of the synthetic resin used. The elasticizing additive is used in a ratio of 1:1, preferably 0.7:1, in particular 0.2:1, advantageously 0.01:1, relative to the synthetic resin. Therefore, the elasticizing additive is preferably not used as a main component of the binder, especially not as a main component in terms of amount. The elasticizing additives are added to the binder, for example melamine resin, before its application to the fibers and are applied to the fibers together with the binder and the filler. Alternatively, the elasticizing agent may be applied to the fibers before or after the binder or filler.

According to an advantageous embodiment of the invention, the board-shaped material comprises hydrophobizing agents, for example paraffin or wax, which are typically used in amounts of up to 5% by weight based on the weight of the board-shaped material, typically in amounts of up to 2% by weight, often in an amount of 0.1% by weight to 1% by weight. The use of hydrophobizing agents also helps to reduce the tendency of the board-shaped material to swell.

The disclosure further relates to a method for manufacturing a board-shaped material comprising fibers and binder and filler, wherein the proportion of the binder and filler in the board-shaped material is greater than 50% by weight, comprising the steps of:

• supply of fibers,

• supply of the binder, preferably in liquid form, and optionally an elasticizing additive,

• cargo supply,

• application to the fibres of the binder and filler, as well as the optionally used elasticising additive,

• formation of a fibre cake,

• pressing the fibre cake in a press while the binder cures to produce a board-shaped material.

The steps of the method correspond to those of a conventional method, for example for the manufacture of a wood-based panel in a press. According to the invention, however, a greater amount of binder and filler and of the optionally used elasticizing additive is used than previously known, so that the proportion by weight of the binder and filler and of the optionally used elasticizing additive is greater than the proportion by weight of the fibers.

If synthetic or inorganic fibres are used, it may be necessary to at least partially dry the binder on the fibres. If the fibres contain moisture, as is usual in the case of lignocellulosic fibres, for example, the moisture content must be adjusted before pressing the fibre cake, so that a dimensionally stable board is obtained after pressing, which does not swell or shrink. Lignocellulosic fibres are often used with a moisture content of up to 120% by weight or more before gluing. Lignocellulosic fibres can be dried before or after applying the binder and filler. During pressing, it is preferred that the lignocellulosic fibres have a moisture content of at least 3% by weight to a maximum of 15% by weight, i.e. with a water content of at least 3% by weight to 15% by weight based on the total weight of the fibres.

The binder is usually supplied in liquid form. It may be supplied in pure form or, as is more commonly done, in solution, either in solvent or water or as a dispersion or emulsion. The filler is provided in particulate form. It is considered an independent invention to process binder monomers or oligomers together with the filler to form a binder or a filled binder. When the binder is produced from monomers or oligomers, for example, the filler material is dispersed and the binder is produced in the presence of water or solvent, if necessary with agitation. Before it is applied to the fibers, the binder and filler mixture is agitated again if necessary.

The application of the binder and filler to the lignocellulosic fibres is typically carried out by spraying, for example by a plurality of spray nozzles which produce a spray mist of the binder and which are arranged around a downward flow of fibres. Preferably, the binder and filler are mixed before application to the fibres or the mixture of binder and filler described above is used. The elasticising additive is also added before, during or after application of the binder or filler, typically by spraying. A common design of such an application device is, for example, a blow line, which is used in the production of fibreboards. The surface of the fibres is wetted with droplets of binder or with a mist of binder, wherein the binder is optionally mixed with filler. Alternatively, the filler may be applied separately from the binder, simultaneously or with a time delay, by spraying or dispersing. The fibres, moistened with binder and filler if necessary, are formed into a fibre cake and pressed after optional drying. The binder hardens in the process, resulting in a board-like material. In contrast to WPC products, irreversible chemical bonds are formed between the fibres and the binder, but also within the binder, during curing, which takes place practically at the top and bottom of the fibre cake under the influence of pressure and temperature. The process according to the invention avoids the kneading and extrusion effort.

Surprisingly, it has been found that the pressing conditions are practically the same as those of known wood-based materials with a reduced proportion of binder and filler compared to the invention. The pressing pressure, temperature and time are in the range of, for example, conventional HDF boards (high-density fibreboard). The material according to the invention can be produced excellently in presses such as those used for the production of wood-based materials. Continuous or discontinuous hot presses are particularly suitable, for example continuous double-belt presses with rotating and heated metal belts or presses working in cycles. This makes it possible to produce board formats which, unlike WPC, are not limited to the production of narrow plank formats with a width of approximately 30 cm. Instead, conventional board formats, as is usual for wood-based panels, can be supplied.

The fibre cake is usually produced by spreading, as is usual with wood-based materials. The fibres, freshly glued or preferably dried with the full amount of binder and filler, are spread on a support, usually a conveyor belt, generally in a homogeneous layer, but alternatively also in several layers, whereby the layers can have a different composition as regards fibres, binder, filler, elasticising additive, aggregates or additives. The filler can also be added when spreading the fibre cake. The spread fibre cake first passes through a pre-press on the support and is then pressed in a press. According to the invention, the press acts on the top and bottom of the fibre cake or the board-shaped material.

Any press that applies sufficient pressure and temperature is suitable, both a plate press, in which the material is pressed between two metal sheets, and in particular a continuous press, in which the material is pressed between two circulating metal strips. Hot presses with rotating pressing plates or metal strips that are heated to a predetermined temperature are preferably used. Suitable pressing temperatures can be selected between 100 °C and 220 °C, preferably between 110 °C and 160 °C. The thinner the board, the lower the pressing temperature can be selected. Suitable pressing pressures are, for example, in a range of 0.3 N/mm2 to 5.5 N/mm2, in particular 1 N/mm2 to 3 N/mm2. Advantageously, the pressing time is 6 seconds/mm of panel thickness (hereinafter: s/mm) to 60 s/mm, typically 10 s/mm to 30 s/mm. In continuous presses, the feed rate of the circulating metal strips between which the panel-shaped material is produced by pressing is usually between 100 mm/second and 1000 mm/second.

The actual pressing process may be preceded by a pre-pressing to compact the fibre cake. Optionally, a device for cooling the board-shaped material can be connected downstream of the press, in particular a device for cooling under a predetermined pressing pressure, which may be lower than the pressing pressure during pressing of the material.

The additives, aggregates or hydrophobizing agents described above may be added to the material according to the invention, usually before or during the formation of the fiber cake.

The material produced according to the method of the invention preferably has a surface essentially comprising binder and filler, optionally the elastifying additive, even more preferably a surface comprising binder and filler or the elastifying additive. In particular, when hygroscopic fibres, for example lignocellulosic fibres, are used, the aim is to have as few fibres as possible on the surface of the material in order to maximally optimise thickness swelling. The addition of kaolin and other fillers, which are non-hygroscopic materials which nevertheless guarantee high water absorption, contribute in particular to the requirement of producing a board-shaped material which does not swell. This makes it possible to absorb water when the humidity is high, for example, and to release it again when the humidity is lower. Due to the filler, the board-shaped material according to the invention has a slightly sandy surface. However, this does not affect the treatment and processing of the surface. The stacking of the material according to the invention is easy and slip-free.

The material according to the invention can be processed as a wood-based board, for example as an HDF board. The surface can be coated, embossed or milled; the edges can be profiled, for example for the production of floor panels. The board-shaped material according to the invention can be laminated with resin-impregnated synthetic papers, printed, painted, varnished or otherwise processed, in particular coated. An advantage of the invention is that the board-shaped material can be treated and processed in existing devices.

The board-shaped material according to the invention can be adapted to different requirements by different combinations of fibres, binder, filler, optionally added elasticising additive, aggregates and possibly other additives such as waxes. It is therefore expressly pointed out that the features described above can be freely combined with each other.

According to the invention, a thickness swelling is considered to be less than 5%, preferably less than 3%, in particular less than 2% relative to the original thickness of the board. The board-shaped materials optimized for minimum thickness swelling according to the invention have a thickness swelling according to DIN 317 or an edge swelling according to DIN 13329 of only 0.5% to 1%. The board-shaped material according to the invention is therefore only slightly swelling or, if a maximum thickness swelling of up to 1% of the original thickness of the board is achieved, does not swell and is dimensionally stable. This means, for example, that a board-shaped material that is practically non-swelling and dimensionally stable against water or moisture can now be produced in known devices for the production of wood-based boards, which is not limited to narrow formats and which preferably maximizes the use of renewable raw materials.

The invention is explained in more detail below using exemplary embodiments. It is shown:

Figure 1

a schematic representation of a board-shaped material according to the invention.

The figure shows a board-shaped material 1 with a top 2 and a bottom 3 as well as an edge 4. The material has fibres 5 which are embedded in binder and filler. The proportion of binder and filler is more than 50% by weight of the board-shaped material. This means that more binder and filler are used than fibre 5. Natural, synthetic, organic and inorganic fibres can be used as fibres, both individually and in mixtures. Hygroscopic fibres such as wood, cellulose or flax fibres can also be used. MF resin is the preferred binder, but melamine-phenol resin can also be used, often together with PMDI. Together with can mean that both resins are used simultaneously or one after the other. Examples of fibre and binder combinations are described below. Kaolin is the chosen filler.

Two comparative examples and one embodiment are explained in more detail below, as shown in Table 1, parts 1 and 2. Comparative example 1 is shown in row 1, comparative example 2 in row 2, and embodiment 1 in row 3.

Comparative example 1

The results of comparative example 1 are shown below in Table 1, for which lignocellulosic fibres are used, in this case softwood fibres. The fibres were produced from steamed wood chips by defibre removal in the refiner. Alternatively, any other lignocellulosic fibre or mixtures of such fibres can be used. The softwood fibres are used at a moisture content of 120 % before sizing; before pressing, they are dried with the binder on them to a residual moisture content of 6 %, i.e. one tonne of fibres contains 60 kg of water.

For this test, more than 100% by weight, in this case approximately 105% by weight of wood-based binder, hereinafter referred to as Fibrasatro, is used, in this case a binder comprising melamine-formaldehyde resin (MF resin). The melamine-formaldehyde resin (MF resin) used in the binder has a solids concentration of 60% (measured at 60 min/120 °C). 175 grams of liquid binder containing 105 g of MF resin was applied to 100 grams of Fibrasatro material, taking into account the liquid content (105 g with a solids concentration of 60% = 175 g). In this document, "wood-atro" or "fibrasatro" refers to lignocellulosic fibers that have been dried at 105 °C to a constant weight. "Woodiness" is a common reference measurement for formulations containing lignocellulosic fibers. In other embodiments, binder usage is taken into account.

In addition, 5% by weight of paraffin relative to the wood is used. In addition, 2% by weight of ammonium sulphate relative to the fibres is used. The binder is applied to the lignocellulosic fibres in four passes, with one quarter of the binder being applied to the fibres in each pass. The liquid binder is sprayed through nozzles in a known fibre sizing device. The spray mist generated by the nozzles is deposited on the surface of the fibres passing through the spray mist, for example by falling from top to bottom through the binder spray mist. Since Table 1 shows the components of the board-shaped material in absolute values, the sum of these components may be higher than the specified gross density, for example because volatile components evaporate or vaporise during the pressing process.

The fibre sizing device is followed by drying of the glued fibres in drying media, for example a tunnel or hot air shaft, which apply heated air to the fibres. The aim of drying is not to completely remove the liquid, but to dry the binder to such an extent that it no longer sticks. The reactivity of the binder during curing under the influence of pressure and/or temperature must not be affected by drying.

After drying, the fibres can be stored or further sizing or processing is carried out. A second pass through the sizing device is then carried out, in which another quarter of MF resin is sprayed onto the fibres that have already been previously sized after the first pass. Even after the second pass, the bonded fibres are dried until they no longer adhere or stick to each other. A third and fourth pass through the sizing device and drying means is also carried out in the same way. Alternatively, the 105% by weight binder can also be applied to the fibres in one or two passes, or in five or more passes. The amount of binder applied to the fibres per pass can vary from pass to pass.

The glued fibres are processed into a board-shaped material with a thickness of approximately 4.3 mm. For this purpose, a fibre cake is rolled out and pressed in a known double-belt press operating continuously at a feed rate of 410 mm/s at 180 °C and a pressure of 2.5 N/mm2 with a pressing time of approximately 20 s/mm of board thickness. After pressing, the board produced in this way has a gross thickness of 4.6 mm and a density of 1200 kg/m3. The pressed board is sanded to a thickness of approximately 4.3 mm. For continuous presses, the temperature specification refers to the press inlet. Immediately after pressing, the board has a gross width of 2.14 m and is trimmed to a finished net width of 2.07 m.

The board-shaped material produced in this way is subjected to swelling tests according to DIN 317 and edge swelling tests according to DIN 13329. The thickness swelling is determined at one edge of the material as a change in mm relative to the thickness of 4.5 mm in absolute terms and also as a relative change (%).

Comparative example 2

For the fibre content of the board-shaped material according to embodiment 2, the same amount of fibres is used as in comparative example 1 according to Table 1.

The proportion of fibersatro is about 47% by weight of the board-shaped material. The proportion of binder is composed as follows: about 84% by weight of MF resin and about 21% by weight of an elasticizing additive, in this case styrene acrylate, in each case based on the proportion of fibersatro. The MF resin and styrene acrylate are applied separately to the fibers. The amount of binder and elasticizing additive is greater than the amount of fibers used. In addition, ammonium sulfate and paraffin are used in the same amounts as in comparative example 1.

The elasticizing additive, which replaces parts of the melamine, reduces the brittleness of the board-shaped material. This did not affect the swelling properties of the board-shaped material.

Example of implementation 1

Embodiment example 1 is based on comparative example 2. As can be seen from Table 1, parts 1 and 2, the same amounts of fibres, elasticising additive, ammonium sulphate and paraffin are used. The board-shaped material is manufactured in the same way and under the same conditions, unless otherwise described below.

In embodiment 1, the amount of melamine used is reduced to approximately 59% by weight relative to the amount of saturated fibres used. In addition to comparative example 2, filler, in this case kaolin, is used. The amount of filler used is approximately 26% by weight based on saturated fibres.

The proportion of binder, filler and elasticizing additive is higher than the proportion of fibres in the board-shaped material. To produce a binder-filler mixture, MF resin (trade name: WDF-04) and mineral filler (kaolin) are used. The binder was first mixed with kaolin. Specifically, the mentioned proportions of melamine resin and kaolin are mixed for a production batch. The kaolin was metered directly into a reactor after the production process of the MF resin (WDF-04) was completed, i.e. after at least partial polymerisation of the melamine-formaldehyde polymer. The pH value was optionally corrected upwards with caustic soda because kaolin has a slightly acidic effect (pH 5.5). In this way, the kaolin was mixed with the ready-to-use MF resin until a uniform mixture was achieved. The product is homogeneous until the end of use (no sedimentation observed), being completely used within 24 hours. The mixture of MF resin and kaolin remained liquid and sprayable. The amount of kaolin is 20% by weight based on the MF resin, calculated as a solids content of 100% by weight. The elasticizing agent, an acrylate dispersion with the trade name AS 2040, was sprayed separately onto the fibres before the board was manufactured.

Nothing special was found during the production of the board according to the invention; the application of the MF resin-kaolin mixture to the fibres and the subsequent production of the board proceeded without problems. When stacked, the filled boards proved to be less slippery than comparable boards. The coated board, with kaolin as filler, has an edge swelling value of less than 1 %. It has therefore been found that the binder can be partially replaced by filler without any change in the properties of the board-shaped material.

In each of the following exemplary embodiments, a support board according to exemplary embodiment 1 is used, which is coated on the top and optionally provided with impact sound insulation, for example laminated cardboard, on the bottom.

Example of implementation 2: Pressed support board with paper structure

A decorative paper and a coating are placed on top of the carrier board; optionally, a backing is placed underneath the bottom of the board. This three- or four-layer pressed material stack is pressed in a short-cycle press. The coating, the decorative paper and the optionally used backing are used as impregnations of synthetic resin-impregnated paper. The result is a coated carrier board that is more resistant to acids and alkalis, but also with a higher abrasion resistance compared to uncoated carrier board, and an aesthetically pleasing decor with a synchronized structure.

In embodiment 2, a decorative paper with a total weight of 110 to 200 g/m2 and a decorative print of 1 to 6 colours is used as the paper impregnation. Furthermore, the decorative paper impregnation is carried out by resin impregnation based on urea or melamine resin or a mixture of the two resins before or after printing, whereby the synthetic resin is applied in liquid or solid form, in particular in powder form. The synthetic resin is then dried, but not yet cured, until it is in state B with a weight of 60 g/m2 to 110 g/m2.

Furthermore, a coating is used as a paper impregnation with a total weight of 120 to 400 g/m2, based on a raw paper with a weight of 30 g/m2 to 70 g/m2, a resin impregnation based on melamine resin, which is applied aqueous or as a solid, in particular in powder form, and which is present after drying in state B, i.e. not yet cured, with a weight of 85 g/m2 to 280 g/m2, and a filler with corundum.

Finally, an optional backing is used as a paper impregnation with a total weight of 150 g/m2 to 240 g/m2, made from a raw paper and a resin impregnation based on urea and/or melamine resin or mixtures of both resins, which is applied in aqueous form or as a solid, in particular in powder form.

As an alternative or in addition to a backing board, impact sound insulation, for example a layer of cardboard, card or EPS, can be attached to the underside of the carrier board, usually by laminating, i.e. gluing the impact sound insulation using an adhesive.

The subsequent production of the coating on the workpiece is carried out by producing a stack of pressed material which, from top to bottom, has the coating as paper impregnation, the decorative paper as paper impregnation, the backing board and, optionally, the backing board as paper impregnation. The stack of pressed material is pressed to form a laminate in a short-cycle heat press, where the short-cycle press has an upper pressing plate acting on the coating and a lower pressing plate acting on the bottom of the backing board or the backing board, and where the short-cycle press is set up as shown below:

• a pressure of at least 25 kg/cm2 and

• an elevated temperature of 180°C to 220°C, preferably 200°C, measured at the pressing plate, and

• a pressing time of 6 to 30 seconds.

A coated carrier board is produced by forming a surface structure by means of the upper pressing plate, which optionally has a decoration-adaptable structure at least in sections (so-called "in-register embossing").

The coated support board produced in this way is dimensionally stable even under the influence of water, does not swell and does not show deformations on the surface, i.e. it does not bend or warp.

Example of implementation 3: Backing board with decorative paper, coating and paint layer

One or more layers of paint can be applied to the coating, to which a structure is applied according to exemplary embodiment 2, in particular to adjust surface properties such as gloss, high-gloss finish or surface mattness, or to create anti-fingerprint properties. The paint is preferably applied as UV paint, typically in two or three layers, whereby in the case of multi-layer paint application, preferably, the already applied layer is gelled after the application of each paint layer. After the last paint layer has been applied, the paint layers are completely cured. The adhesion of the paint layer to the coating can optionally be improved by applying a primer to the coating before applying the paint.

A common example of applying paint to a coating is, for example, by means of a water-based “hydrolacquer”, e.g. a UV-curing acrylic paint. A first layer of 10 g/m2 paint is applied to the coating surface and allowed to gel. This layer acts as an adhesion promoter between the synthetic resin of the coating and the subsequent paint layers. For example, to achieve a paint coating with a total layer thickness of 50 g/m2, a second layer of 28 g/m2 hydrolacquer is applied over the first layer, followed by two further layers of 6 g/m2 hydrolacquer. After each layer, the applied paint can gel; after all layers have been applied, the applied paint is fully cured. The paint can be applied in any way, by pouring, spraying, roller application or scraping.

The paint coating is preferably supplemented, usually in the last layer or two layers, with corundum with a diameter of preferably 1 pm to 5 pm to improve the scratch resistance of the paint surface. The corundum is preferably spread on a paint layer that has not yet cured.

The coated carrier board produced as a laminate in this way is waterproof and dimensionally stable. It can be used as a floor, wall or ceiling covering, as a structural element for interior fittings, as a structural element for exterior constructions, in vehicle manufacturing or for façade design.

Exemplary embodiment 4: Backing board with PVC coating layer

The carrier board is laminated with a PVC layer as described above in embodiment 1. For this purpose, an adhesive is applied to the top of the carrier board, for example in an amount of 60 g/m2 to 100 g/m2. All hot-melt adhesives can be used to fix the PVC layer; however, a waterproof polyurethane-based hot-melt adhesive is preferred. A PVC layer with a decoration on the outside is placed with its inner side on the adhesive of the carrier board. The PVC layer usually has a thickness of between 1 mm and 5 mm.

The stack consisting of the backing board, adhesive and PVC layer is pressed in a laminating press using pressure and usually high temperature until the hot melt adhesive has essentially developed its adhesive strength.

A PVC-coated backing board can be used, for example, as a waterproof panel for a floor covering, but also for constructions in outdoor buildings, for example for facades or structural elements such as partition or privacy walls.

Example of implementation 5: Support board with wood veneer

A support board according to the invention is covered with an oak veneer on the top only or on the top and bottom. If only a veneer is applied to the top, it is advantageous to apply a backing to the bottom to prevent the board from warping.

An adhesive, which fixes the veneer by its adhesive effect, or a binder, which here is preferably a partially cross-linked binder, is introduced between the veneer and the support board. The binder does not develop adhesive forces like an adhesive, but rather binds the veneer by the action of pressure and temperature, mechanically anchoring it on the surface of the support board and the veneer, or forming chemical bonds with the surface of the support board and the veneer.

The partially cross-linked binder is advantageously a synthetic resin, advantageously a thermosetting material, in particular an aminoplast; preferably the binder has, for example, melamine resin such as melamine-formaldehyde resin. The binder can be used in sufficient quantity to fix the veneer to the top or bottom of the support board. The binder can optionally be introduced in the form of binder-impregnated paper. The binder can be applied to the veneer or to the top or bottom of the support board. The paper can be symmetrically impregnated with binder or an excess of binder can be applied to at least one side of the paper.

The veneer is fixed to the carrier board by means of a press. If adhesive is used to fix the veneer, for example a vacuum press can be used for fixing, which causes the adhesive to fix the veneer to the carrier board. The veneer is generally not compressed here. If an adhesive agent instead of a binder is used to fix the veneer, for example a short-cycle press can be used, in which the synthetic resin is subsequently cross-linked at temperatures of 100 °C to 240 °C and at a pressure of 25 N/mm2 to 50 N/mm2 within a period of 20 seconds to 60 seconds to have cured. The liquid synthetic resin at least partially penetrates into the veneer during the subsequent cross-linking; optionally, in particular if an excess of binder is used, the binder penetrates at least partially through the veneer. In a preferred alternative, so much excess binder is used that the synthetic resin penetrates completely into the veneer and forms the outer surface of the backing board covering. The veneer is usually also compressed to the above pressure. When a binder is used, the veneer is more resistant to pressure after compression and offers a less sensitive surface than an uncompressed veneer.

The binder is used to impregnate the paper in liquid form and then dries in a partially cross-linked state. Alternatively, it can also be used partially in solid form, for example in powder or dust form, which adheres to the partially cross-linked and still liquid binder.

Alternatively, a polyurethane prepolymer can be used for direct application to the surface of the backing board or veneer. If the veneer is subsequently exposed to light, an aliphatic isocyanate is preferred as the polyurethane prepolymer; if yellowing or discolouration is not a problem, an aromatic isocyanate can also be used as the polyurethane prepolymer. The veneer and backing board can be pressed together under the above-mentioned pressing conditions, for example in a short-cycle press.

An additive can be applied to the surface of the binder facing the veneer. The additive can influence, for example, the colour, conductivity or light resistance.

Additives can also be used in combination with each other. If the additive is applied to the surface of the binder, it is transported through the veneer during subsequent cross-linking in the press by the liquefied binder to the point where the binder penetrates into the veneer. In this way, maximum effect is achieved with minimum use of additive.

The supporting board thus covered with wood veneer can be additionally coated, in particular sealed against the influence of moisture, for example, the wood veneer can be varnished.

If the binder forms the surface of the veneered backing board or if a seal is subsequently applied to protect against moisture, then the waterproof backing board with a decorative, but waterproof coating can be used in damp rooms, for example as floor covering or for furniture, in particular bathroom or kitchen furniture or for equipping saunas or swimming pools.

In general, the following should be noted with regard to the production of the board-shaped material: For the production of the board-shaped material, a continuous or discontinuous press is preferably used, in particular a thermal press. The pressing temperature is advantageously 100 °C to 220 °C, preferably 110 °C to 160 °C. The pressing pressure is advantageously 0.3 N/mm2 to 5.5 N/mm2, preferably 1 N/mm2 to 3 N/mm2. The pressing time is advantageously 6 seconds/mm of board thickness to 60 seconds/mm of board thickness, preferably 10 seconds/mm of board thickness to 30 seconds/mm of board thickness.

In general, the following should be noted with regard to the board-shaped material according to the invention: Ceramic, synthetic or glass particles are preferably used as additives. The board-shaped material preferably contains hydrophobizing agents, for example paraffin or wax. Advantageously, a coating is applied to a top and/or a bottom part of the board-shaped material. The board-shaped material has natural fibers, synthetic fibers, inorganic or organic fibers or fiber mixtures.

Table 1, part 1

Table 1, part 2

Claims (15)

1. Method for the production of a board-shaped material with a thickness swelling which, according to DIN 317, is less than 5 % in relation to the original thickness of the board, comprising lignocellulosic fibres (5) obtained from plants by chemical or physical methods, and binder and filler, wherein melamine resin, formaldehyde resin, phenolic resin, methylenediphenyl isocyanate (MDI), also in emulsified form as eMDI, polymeric diphenylmethane diisocyanate (PMDI), polyurethane or mixtures of the mentioned binders are used as binders, and wherein the proportion of the binder and the filler is more than 50 % by weight of the board-shaped material (1), comprising the steps of: a. supply of lignocellulosic fibers (5), b. supply of the binder, preferably in liquid form, c. cargo supply, d. application of binder and filler to the fibers (5), e. formation of a fibre cake from the fibres provided with binder and filler (5), f. pressing the fibre cake in a press while the binder is curing to produce a board-shaped material (1) with a thickness of 3 mm to 80 mm and a density of between 1000 kg/m3 and 1800 kg/m3. 2. Method according to claim 1, characterized in that silicates such as aluminum or magnesium silicate, carbonates such as magnesium carbonate or calcium carbonate, metal oxides such as titanium dioxide or aluminum trioxide, metal hydroxides such as aluminum trihydroxide, barium sulfate or calcium sulfate dihydrate, as well as mixtures of the aforementioned fillers are used as fillers. 3. Method according to claim 1 or 2, characterized in that at least 1% by weight and up to 30% by weight of the filler is used, in each case based on the board-shaped material (1). 4. Method according to claim 2, characterized in that the aluminum or magnesium silicate is used in hydrated form. 5. Method according to any of the preceding claims, characterized in that the binder and the filler are mixed before being added to the fibers (5). 6. Method according to any of the preceding claims, characterized in that an elasticizing additive is used. 7. Method according to claim 6, wherein the elastifying additive is used as a solid in relation to the solid of the binder in a ratio of at most 1:1, preferably 0.7:1, in particular 0.2:1, advantageously at least 0.01:1. 8. Board-shaped material with a thickness swelling which, according to DIN 317, is less than 5 % relative to the original thickness of the board, produced by the method according to any one of claims 1 to 7, comprising lignocellulosic fibres (5) which have been obtained from plants by chemical or physical methods, binder and filler, wherein the proportion of binder and filler is greater than 50 % by weight of the board-shaped material (1), and wherein the binder is melamine, formaldehyde, phenolic resin, methylene diphenyl isocyanate (MDI), also in emulsified form as eMDI, polymeric diphenylmethane diisocyanate (PMDI), polyurethane or mixtures of the mentioned binders, and wherein the board-shaped material has a thickness of 3 mm to 80 mm and a density of 1000 kg/m3 to 1800 kg/m3. 9. Board-shaped material according to claim 8, characterized in that silicates such as aluminum or magnesium silicate, carbonates such as magnesium carbonate or calcium carbonate, metal oxides such as titanium dioxide or aluminum trioxide, metal hydroxides such as aluminum trihydroxide, barium sulfate or calcium sulfate dihydrate, as well as mixtures of the aforementioned fillers are used as fillers. 10. Material according to claim 8 or 9, characterized in that the material (1) has an elasticizing additive, in particular an elastomer or a thermoplastic. 11. Material according to claim 10, characterized in that polyvinyl acetate, ethyl vinyl acetate, acrylate, styrene acrylate, polyurethane, mono or diethylene glycol are used as elasticizing additives. 12. Material according to any one of claims 8 to 11, characterized in that the proportion of binder and filler relative to the wood is greater than 101% by weight, preferably greater than 120% by weight, in particular greater than 150% by weight, advantageously greater than 200% by weight. 13. Material according to any of the preceding claims 8 to 12, characterized in that the aluminium or magnesium silicate is used in hydrated form. 14. Material according to any of the preceding claims 8 to 13, characterized in that the board-shaped material (1) comprises an additive, in particular non-hygroscopic or non-swelling additives. 15. Use of a board-shaped material according to at least one of claims 8 to 14, wherein the board-shaped material (1) with a thickness swelling according to DIN 317 of up to 5 %, based on the original thickness of the board, and with a thickness of 3 mm to 80 mm and with a density of 1000 kg/m3 to 1800 kg/m3, is used in interior fittings, in particular as a floor board or floor laminate, as a wall or ceiling board, as a furniture board, in the finishing of damp and wet rooms, in outdoor constructions as a facade or roof board, for stables, for terrace construction, including decking or flooring and outdoor constructions, in particular furniture for outdoor areas.