RS54924B1 - LIGNOCELLULOSIC MATERIALS WITH LIGNOCELLULOSE FIBERS IN THE OUTER LAYERS AND EXPANDED PLASTIC PARTICULARS IN THE CORNER, AS METHODS AND THEIR APPLICATIONS - Google Patents

Abstract

Lignocellulosic material composed of a core and two outer layers, containing in the core A) 30% to 98% by weight of lignocellulosic particles; B) 1% to 25 weights of expanded plastic particles with a specific density in the range of 10 to 150kg / m3, C) 1% up to 50% by weight of one or more binding agents selected from the group consisting of phenoplast resin, aminoplast resin and organic isocyanate with at least two isocyanate groups, iD) 0% to 30% by weight of additives and in outer layersE) 70% to 99% by weight of lignocellulosic fibers, F) 1% to 30% by weight of one or more binding agents selected from the group consisting of phenoplast resins, aminoplast resins and organic isocyanate with at least two isocyanate groups, iG) 0% to 30% by weight of additives, which are expanded plastics particles B are unequally distributed in the nucleus, which means that the mass ratio of X expanded plastic particles B to lignocellulosic particles A in the outer regions of the nucleus is different from the mass ratio Y exp and attached plastic particles B to lignocellulosic particles A in the inner region of the nucleus. The application contains 6 more patent claims.

Description

f0001|The present invention relates to lignocellulosic materials that are made of a core and two outer layers, indicated by the fact that the core is made of expanded plastic particles, while the outer layers are made of lignocellulosic fibers. The subject invention further relates to the process of producing lignocellulosic material and to the application of such materials.

[0002] CH-A-370 229 discloses compression molds of low weight but high compressive strength, consisting of wood shavings or wood fibers, a binding agent and a porous foamed or partially foamed plastic that acts as a filling material.

[0003] The disadvantage of these compression molds is that they do not have an outer layer without plastic, which means that the usual coating technologies (for example, coating with a foil of veneer or a short-term layer with a melamine film) give very poor results.

[0004] DE-U-20 2007 017 713 describes lightweight chipboard panels, obtained by mixing wood shavings and evenly applied polystyrene foam grains in the middle layer of this panel.

[0005] The disadvantage of such materials is reflected in the fact that the resistance to bending, the resistance to pulling out screws and the quality of the surface are inadequate for many applications of this material.

[0006] WO-A-2008/046890 discloses lignocellulosic materials consisting of a core and two outer layers, according to the preamble of claims 1 and 2, specifically, it describes a light, single-layer and multi-layer wood material, which contains wood particles, a filler of polystyrene and/or sdren copolymer with a specific density of 10 to 100 kg/m<3> and binders agent. Wood materials are produced from wood veneer, wood shavings or wood fibers, more specifically from wood shavings and wood fibers.

[0007] The disadvantage of this material is reflected in the fact that improving the properties of a given wooden panel can only be achieved by increasing the amount of glue and/or the amount of polymer, which leads to an increase in production costs.

[0008] WO 2008/046890 discloses a light wood material which, as a wood component, contains 30 - 92.5 mass % of wood particles. The wood particles have an average density between 0.4-0.85 g/cm<3>, 2.5-20 mass % of polystyrene and/or styrene copolymer as filling material in relation to the total mass of wood material.

J0009JUS 2011/217562 discloses the process for the production of lignocellulosic material, which is composed of: A) from 30 to 95% by mass of lignocellulosic particles; B) from 1 to 25 mass % of expanded plastic particles, specific density ranging from 10 to 150 kg/m<3>; C) from 1 to 50% by mass of a binding agent, selected from the group consisting of aminoplast resin, phenol-formaldehyde resin and organic isocyanate, with at least two isocyanate groups, and optionally, from

D) additives,

the components are mixed and then pressed at high temperature and high pressure, characterized in that component B contains an agent for strengthening the polymer of component C).

[0010|US 2011/039090 discloses a light wood material with an average density in the range of 200 to 600 kg/m<3>, which contains, in relation to the wood material;

A) from 30 to 95 mass % of wood particles; B) from 1 to 15 mass % of the filling mass with a specific density in the range of 10 to 100 kg/m<3>, selected from the group consisting of foamed plastic particles or plastic particles that are already in the form of foam; C) from 3 to 50% by mass of binding material, which consists of aminoplast resin, or some organic isocyanate, with at least two isocyanate groups and, when necessary

D) additives.

[00111] The objective of the present invention was to overcome the previously mentioned disadvantages, specifically, to provide a light lignocellulosic material with improved properties related to resistance to bending, resistance to bolt extraction and/or to improve surface properties, while these materials retain good processing properties, as conventional high-density wood materials have.

[0012] Accordingly, a new and improved lignocellulosic material was discovered, which consists of a core and two outer layers, whereby the core contains:

A) 30% to 98% by mass of lignocellulosic particles:

B) I % to 25 % by mass of expanded plastic particles, specific density in the range of [From 150 kg/m3, C) I % to 50 % by mass of one or more binding agents, selected from the group consisting of phenoplast resin, aminoplast resin and organic isocyanate with at least two isocyanate groups and

D) 0% to 30% by mass of additives.

and in the outer layers

E) 70% to 99% by mass of lignocellulosic fibers,

F) 1% to 30% by weight of one or more binding materials, selected from the group consisting of phenoplast resin, aminoplast resin and organic isocyanate with at least two isocyanate groups, and

D) 0% to 30% by mass of additives,

characterized by the fact that the expanded plastic particles B are unevenly distributed in the core, which means that the mass ratio X of expanded plastic particles B to lignocellulosic particles A in the outer regions of the core is different from the mass ratio Y of expanded plastic particles B to lignocellulosic particles A in the inner region of the core.

[0013] It is preferable that the lignocellulosic material has a core and two outer layers, consisting of A) 30% to 98% by mass of lignocellulosic particles; B) 1% to 25% by mass of expanded plastic particles, specific density in the range of 10 to 150 kg/m3, C) 1% to 50% by mass of one or more binding agents selected from the group consisting of phenoplast resin, aminoplast resin and organic isocyanate with at least two isocyanate groups and

D) 0% to 30% by mass of additives

and in the outer layers

E) 70% to 99% by mass of lignocellulosic fibers,

F) 1% to 30% by weight of one or more binding materials selected from the group consisting of phenoplast resin, aminoplast resin, and organic isocyanate with at least two isocyanate groups and,

G) 0% to 30% by mass of additives, indicated by the fact that the expanded plastic particles B are unevenly distributed in the core, which means that the mass ratio X of expanded plastic particles B to lignocellulosic particles A in the outer regions of the core is different from the mass ratio Y of expanded plastic particles B to lignocellulosic particles A in the inner region of the core.

[0014] Data on the mass percentage content of components A, B, C, D, I£, F and G refer to the dry weight of the components in question. in relation to the total dry mass. The total sum of the mass percentages for components A, B, C and D is 100% by mass. The total sum of components E, F and G similarly makes 100% of the mass. Also, both layers and the outer and inner core contain water, which is not taken into account in the expression of % content of dry mass. The water may originate from residual moisture present in the lignocellulosic Particles, from the binding agent, from added water to dilute the binding agent, or from wetting of the outer layers, for example. from additives, such as polymer curing agents or aqueous paraffin emulsions, for example, or from other sources, from expanded plastic particles when foamed. for example with the application of steam. The water content in the core and in the outer layers can reach up to 20% by mass. that is, 0% to 20% by mass, preferably 2% to 15% by mass. even more preferably, 4% to 10% by weight, relative to 100% by weight of the total dry weight. The ratio of the total dry weight of the core to the total dry weight of the outer layers is generally 100:1 and 0.25:1, preferably 10:1 to 0.5:1, even more preferably. 6:1 to 0.75:1. and specifically 4:1 to 1:1.[0015JLignocellulosic materials (lignocellulosic materials) according to the present invention can be produced as follows:[0016|The components for the core and the components for the outer layers are mixed separately from each other.

[0017] For the core, the lignocellulosic particles A can be mixed with components B, C and D and/or with the constituents of the components (for example, two or more constituents. such as substances or compounds, for example from the group of one component) according to any desired order. Components A, B, C and D can in each individual case be composed of one, two (Al, A2 or BI, B2, or C1, C2 or Dl, D2) or more component components (Al, A2, A3,..., or BI, B2, B3 Cl, C2, C3,..., or Dl, D2, D3,...). [0018] When the components consist of multiple component ingredients, these component ingredients can be added either as a mixture or each individually. In the case of separate addition, component dependencies can be added directly one after the other, or else at different points in time, not consecutively. In that case, for example. when component C consists of two components Cl and C2, this means that C2 is added immediately after Cl or that Cl is added immediately after C2 or that one or more components or components of components, component B, for example, is added between the addition of Cl and C2. These codes allow components and/or component ingredients to be pre-mixed with other components or component ingredients prior to addition. For example. component additive Dl. can be added to binding agent C or binding ingredient Cl, before this mixture is added to the actual mixture.

[0019] It is preferred above all that the expanded plastic particles B are added to the lignocellulosic particles A and that this mixture is mixed with the binding material C or with two or more components of the binding material Cl, C2, etc. When two or more binding agent ingredients are used, it is preferable to add them separately. Preferably, the additives D are partially mixed with the binding material C or with the ingredients of the binding agent (for example, several ingredients, such as substances or compounds, for example, from a group of components) and then added.

[0020] To make the outer layers, the lignocellulosic fibers E are mixed with the components F and G and/or with the constituents of the components (that is, several constituents, such as substances or compounds, for example, from the group of one component), in any desired order. For the two outer layers, it is possible to use one mixture, or two mixtures. and it is preferable to use the same mixture. |0021] When a component consists of a number of component ingredients, these ingredients can be added either in the form of a joint mixture, or individually. In that case, these component ingredients can be added directly after each other or in some other time order/arrangement, not following each other. It is preferable that the additives G are partially mixed with the binding component F or with the ingredients of the binding component, and then added to the material.

[0022] The resulting mixtures A, B, C, D and E, F. G are stacked on top of each other and compressed in the usual way, at an elevated temperature, in order to obtain a lignocellulosic mold. For these needs, a substrate is formed, indicated by the fact that the substrate is made of these mixtures in the order E, F, G/A, B, C, D/E, F, G ("sandwich construction"). This substrate is compressed in a standard way, at temperatures of 80 to 300°C, preferably 120 to 280°C, more preferably 150 to 250°C and under a pressure of 1 to 50 bar, preferably 3 to 40 bar, even more preferably 5 to 30 bar, in order to form molds. In one preferred embodiment, the substrate is subjected to cold compression before being subjected to high temperature compression. Compression can be carried out by any method known in the art (see examples of methods in "Taschenbueh der Spanplatten Technik", H.-J. Deppe, K. Ernst, 4,<h>Edn., 2000, DRW - Verlag Weinbrenner, Leinfelden Echterdingen, pages 232 to 254, and "MDF- Mitteidichte Faserplatten" H.-J. Deppe, K. Ernst, 1996, DRW- Verlag Weinbrenner, Leinfelden-Echterdingen, pages 93 to 104). These processes use continuous pressing techniques, on single-stage or multi-stage presses, for example. or continuous pressing techniques on two-belt presses, for example. Lignocellulosic material according to the invention generally has an average density of 300 to 600 kg/m<3>, preferably 350 to 590 kg/m<3>, more preferably 400 to 570 kg/m<3>, specifically 450 to 550 kg/rn<J>.

[0024] Lignocellulosic particles of component A are present in the lignocellulosic core material in amounts from 30% to 98% by mass. preferably 50% to 95% by weight, more preferably 70% to 90% by weight, and the base material can be any wood or mixture. for example, spruce, beech, pine, larch, linden, poplar, eucalyptus, ash, chestnut and fir or mixtures thereof. preferably from spruce, beech or their mixture, more specifically, spruce, and may contain parts of wood, for example, wood slats, wood strips, wood shavings, wood fibers, wood dust or their mixtures, preferably wood shavings, wood fibers and their combinations - the kind that are used to obtain laminates, MDF (medium density board materials) and HDF (high density board materials). Lignocellulosic particles can also be obtained from woody plants, such as yan, hemp, cereals or some annual plants, preferably from flax and hemp. The use of wood shavings used in the production of laminates is particularly desirable. If different lignocellulosic particles are used, for example, a combination of wood shavings and wood fibers, or wood shavings and wood dust, then it is preferable that the proportion of wood shavings is at least 75% by mass, that is, 75% to 100% by mass, more preferably not less than 90% by mass, that is.

90% to 100% by mass. The average density of component A is usually 0.4 to 0.85 g/cm<3>, preferably 0.4 to 0.75 g/cm<3>, more specifically 0.4 to 0.6 g/cm\

[0025] It is common for the starting material for lignocellulosic particles to be wood forestry, residues from cutting trees, residues of industrial wood construction and used wood, as well as plants containing wood fibers. A processing procedure to obtain the desired lignocellulosic Particles, wood particles, such as wood shavings and wood fibers, for example. can be carried out according to one of the procedures (for example, M. Dunky, P. Niemz, Holzwerkstoffe und Leimc, pages 91 to 156, Springer Verlag Heidelberg, 2002). |0026]In the lignocellulosic material of the outer layer, the lignocellulosic fibers of component C are present in an amount of 70% to 99% by mass, preferably, 75% to 97% by mass, more preferably 80% to 95% by mass. which constitutes at least 75% of the mass, that is, 75% to 100% of the mass, of lignocellulosic fibers, preferably at least 85% of the mass, that is, 85% to 100% of the mass. more preferably at least 95% RNAse, that is, 95% to 100% by mass. Sometimes it is very desirable that lignocellulosic fibers make up 100% of the mass. As raw materials, wood materials of all types of wood or woody plants mentioned as components A can be used. After mechanical grinding by grinding, fibers can be obtained by grinding, after hydrothermal pretreatment. for example. The fiberization process, fiberization, is described by Dunky, Niemz, Holzwerkstoffe und Leime. Technologie und Einflussfaktoren, Springer, 2002, pages 135 to 148, for example. The average density of component E is usually 0.3 to 0.85 g/cm<3>, preferably 0.35 to 0.8 g/cm<3>, even more preferably 0.4 to 0.75 g/cm<3>.

[0027] Component A may contain usually small amounts of water. from 0% to 10% by mass, preferably 0.5% to 8% by mass, more preferably 1% to 5% by mass (in a usually small range of variation from 0% to 0.5% by mass, preferably, 0% to 0.4% by mass. more preferably 0% to 0.3% by mass). This number refers to 100% of the mass of the absolutely dry wood substance and indicates the water content of component A after drying (using usual procedures known in the art), immediately before mixing with the first component or with the first constitutional component or with the first mixture selected from B, C and D.

[0028] In one preferred embodiment, component E can contain small amounts of water from 0% to 10% by mass, preferably from 0.5% to 8% by mass, more preferably from 1% to 5% by mass (in the usual ranges of fluctuation from 0% to 0.5% by mass, preferably 0% to 0.5% by mass, more preferably 0% to 0.3% by mass). This figure refers to 100% of the mass of the absolutely dry wood substance and describes the water content of component E after drying (by methods known in the art), immediately before mixing with the first component or component component or mixture selected between F and G. |0029]In the following preferred embodiment, component E can contain water in a ratio of 30% to 200% by mass, preferably 40% to 150% by mass. preferably 50% to 120% by mass (in the range of fluctuations from 0% to 20% by mass, preferably 0% to 10% by mass. more preferably 0% to 5% by mass). This figure refers to 100% of the mass of absolutely dry wood substance. and describes the water content of component E before mixing with the first component or with the first ingredient of the component or with the first mixture selected between F and G. In this form of embodiment, after the addition of a portion of all components and/or component ingredients, drying follows, which takes place using methods known in the state of the art; preferably, this drying process takes place after the addition of all components.

[0030] Preferred expanded plastic particles (component B) include expanded plastic particles, preferably expanded thermoplastic particles, with a specific density of 10 to 150 kg/m<3>, preferably 30 to 130 kg/m3, more preferably 35 to 110 kg/m\ more specifically 40 to 100 kg/m' (determined on the basis of a defined volume filled with dense material).

[0031] Expanded plastic particles B are generally in the form of spheres or grains with an average diameter of 0.01 to 50 mm, preferably 0.25 to 10 mm, more preferably 0.4 to 8.5 mm, more specifically 0.4 to 7 mm. In a further preferred embodiment, the spheres have a small surface area per unit volume, in the form of a round or elliptical particle, for example, and it is preferable that the spheres have a closed cell structure. Proportions with an open cell structure according to DIN ISO 4590 are generally not more than 30%, that is, 0% to 30%. preferably 1% to 25%, more preferably 5% to 15%.

[0032] Preferred polymers on which expandable or expanded plastic particles are based are basically based on all known polymers. or on their mixtures. preferably on thermoplastic polymers or their mixtures. which can be translated into foam form. Examples of highly preferred polymers include polyketones. polysulfones, polyoxymethylene, PVC (rigid and flexible), polycarbonates, polyisocyanurates, polycarbodiimides, polyacrylamides and polymethacrylamides, polyamides, polyurethanes, aminoplast resins and phenolic resins, styrenic homopolymers (hereafter referred to as "polystyrene" or "styrene polymef"), styrenic copolymers, Ci-Ckj olefin homopolymers, C2-Cioolefin copolymers and polyesters. The use of 1-alkenes, for example, ethylene, propylene, 1-butene, 1-hexene and 1-octene, is preferred for the production of the indicated olefinic polymers. [0033]Polymers, preferably thermoplastic. they can be mixed with common additives, with which they form the basis for expandable or expanded plastic particles B), such as UV stabilizers, antioxidants, coating materials, hydrophobic agents, nucleators, non-flammable agents, soluble and insoluble, organic and/or inorganic colors, pigments and particles that do not conduct heat, such as carbon black, graphite or aluminum powder, together or spatially separated, as adjuvants.

(0034|Component B can be obtained as follows:

[0035| Suitable polymers, with the use of a medium capable of expansion (also referred to as an expanding medium um) or those containing an expanding medium um. they can be expanded by exposure to microwave radiation, heat energy, hot air. preferably pairs. and/or altered pressure (this expansion is often referred to as "foaming") (Kuntstoff Handbuch 1996, volume 4, "PolystyroI", Hanser 1996, pages 640 to 673 or US-A-5,1 12,875). During this process, in principle, the expanding agent expands, the particles increase in size, and a cellular structure is formed. The expansion can be carried out in a conventional foaming apparatus. which is designated as "prefoamef". These prefoamers can be permanently installed or portable. Expanding can be done in one or more stages. In a single-phase process, in principle, the expandable particles are first expanded directly to the desired final size. In a multi-phase process, in principle, expandable particles are first expanded to intermediate sizes, and then in one or more phases. they expand. over the appropriate number of steps, to the desired final size. Such compact plastic particles, which are also referred to here as "expandable plastic particles", generally do not have a cellular structure, unlike expanded plastic particles. Expanded plastic particles have a lower residual content of expanding agent, from 0% to 5% by mass, preferably 0.5% to 4% by mass. preferably 1% to 3% by mass, relative to the total mass of plastic and expanding agent. The expanded plastic particles obtained in this way can be placed in temporary storage or used without further intermediate steps. in order to produce component B according to the invention. Expandable plastic particles can be expanded using expanding agents known in the art, for example. aliphatic Cjdo Cm hydrocarbons, such as propane, n-butane, isobutane, n-pentane, isopentane, neopentane, cyclopentane and/or hexane and their isomers, alcohols, chelones, esters, ethers or halogenated hydrocarbons, preferably n-pentane, isopentane. neopentane and cyclopentane. preferably some commercially available mixture of n-pentane and isopentane isomers.

[0036] The amount of expanding agent in expandable plastic particles generally ranges from 0.01% to 7% by mass, preferably 0.01% to 4% by mass. preferably 0.1% to 4% by mass, which in all cases is based on expanded plastic particles containing an expanding agent.

[0037] One preferred embodiment uses styrene homopolymer (here also referred to simply as "polystyrene"), styrene copolymer or mixtures thereof as the sole plastic in component B.

(0038) Polystyrene and/or styrene copolymer of this type can be obtained by some of the polymerization methods known in the state of the art; see, for example, Ullmann's Encyclopedia, Sixth Edition, 2000 Electronic Release or Kunststoff-Handbuch 1996, volume 4 "Polystyrol", pages 567 to 598.

[0039] Expandable polystyrene and/or styrene copolymer is generally obtained by some conventional process by suspension polymerization or by means of extrusion processes.

[0040] In the case of suspension polymerization, styrene, optionally with the addition of other co-monomers, can be polymerized in an aqueous suspension in the presence of common suspension stabilizers, with the use of a catalyst that leads to the formation of radicals. The expanding agent and other common adjuvants can be included in the initial polymerization batch or added to the mixture in another way during the polymerization or after its completion. The resulting granular expandable styrene copolymer impregnated with an expanding agent, after completion of polymerization. it can be separated from the aqueous phase, washed, dried and checked.

[0041] In the case of the extrusion process, the expanding agent can be mixed into the polymer, using an extruder, for example, it can be delivered via a cutter and pelletized under pressure to obtain foam particles or strips. [0042]The previously described preferred and particularly preferred expandable styrene polymers or expandable styrene copolymers have a relatively low content of expanding agents. Such polymers are also referred to as having a "low blowing agent content". A highly preferred process for producing an expandable polystyrene or expandable styrene copolymer with a low blowing agent content is described in US-A-5,112,875. [0043] As described, it is possible to use styrenic copolymers. These styrene copolymers contain at least 50% by mass, that is, 50% to 100% by mass, preferably at least 80% by mass, that is, 80% to 100% by mass of copolymerized styrene, in relation to the total mass of plastic (without expanding agent). Examples of contemplated comonomers include α-methylstyrene, ring-halogenated styrenes, acrylonitrile, esters of acrylic or methacrylic acid with alcohol, having 1 to 8 C atoms, N-vinylcarbazole, malic acid, malic anhydride, (meth)acrylamides and/or vinyl acetate.

[0044] Polystyrene and/or styrene copolymer may include small amounts of copolymerized branching agent, in other words. any compound with more than one double bond. preferably two double bonds. as What is divinylbenzene. butadiene and/or butanediol diacrylate. The branching agent is used in an amount of 0.0005 to 0.5 mol %, relative to styrene. Mixtures of different styrene (co)polymers can be used. Very suitable styrene homopolymers or styrene copolymers are crystalline polystyrene (GPPS), high impact polystyrene (HIPS), anionic polymerized polystyrene or high impact polystyrene (A-IPS), styrene-a-methylstyrene copolymers, acrylonitrile-butadiene-styrene polymers (ABS), styrene acrylonitrile (SAN), acrylonitrile, styrene-acrylic acid ester (ASA), methyl acrylate-butadiene-styrene (MBS), methyl methacrylate-acrylonitrile-butadiene-styrene (MABS) polymers or their mixtures. or in combination with polyphenylene ether (PPE).

(0045) There are advantages of using plastic particles, preferably styrene polymers or styrene copolymers, preferably styrene homopolymers, with a molecular weight in the range of 70,000 to 400,000 g/mol, preferably 190,000 to 400,000 g/mol. very preferably 210,000 to 400,000 g/mol.

[0046] Expanded polystyrene particles or expanded polystyrene copolymer particles can be used, with or without the need to reduce the amount of expanding agent, in order to produce a lignocellulosic substance.

|0047JExpandable polystyrene or expandable styrene copolymer or expanded polystyrene or expanded styrene copolymer usually have an antistatic coating.

J0048JThe expanded plastic particles B are generally in an unmelted state, even after compression to obtain lignocellulosic material, which means that the plastic particles B did not penetrate or impregnate the lignocellulosic particles, but were distributed between the lignocellulosic particles. The Plastic Particles B can be separated from the lignocellulose if necessary by physical separation, for example, after shredding the lignocellulosic material.

[0049] The total amount of expanded particles B in relation to the total dry mass of the core, generally ranges from 1% to 25% by mass, preferably 3% to 20% by mass, more preferably 5% to 15% by mass. It proved to be desirable to adjust the dimensions of the above-described plastic particles B according to lignocellulosic particles, preferably wood particles A), or vice versa.

[0050] This setting is expressed later through the ratio of the corresponding d<*> values (from the Rosin-Rammler-Sperling-Bennet equation) of lignocellulosic particles, preferably wood particles A, and expanded plastic Particles B.

[0051] The Rosin-Rammler-Sperling-Bennet equation is described in DIN 66145, for example.

[0052] These d' values are determined by carrying out a sieving analysis in order, first of all, to determine the particle size distribution of expanded plastic particles B and lignocellulosic particles, preferably wood particles A. analogously to DIN 66165, parts I and 2.

[0053] The values obtained from the sieving test are then entered into the Rosin-Rammler-Sperling-Bennett equation and the d' values are calculated.

J0054|The Rossin-Rammler-Sperling-Bennett equation is as follows:

[0055] The description of the parameters of the equation is as follows:

R, residue (% mass) remaining after the appropriate sieve size

D, particle size

d\ particle size with a residue of 36.8% mass

n. width of particle size distribution

[0056] Highly preferred lignocellulosic particles A, preferably wood particles, have a d" value according to the Rosin-Ramnerler-Sperling-Bennett equation (description and method of determining the d' value as previously described), in the range from 0.1 to 5, preferably 0.3 to 3, and even more preferably from 0.5 to 2.75.

Very suitable lignocellulosic materials are obtained when the d' values, obtained according to the Robin-Rammler-Sperling-Bennet equation, for lignocellulosic particles, preferably wood particles A, and for particles of expanded plastic particles satisfy the following ratio:

d' particle A < 2.5 x d' particle B, preferably

d' Particle A < 2.0 * d' particle B, even more preferably

d' particle A < 1.5 x đ<*>particle B, very desirable

d' particle A < d' particle B.

[0058] The total amount of binding agent C. in relation to the total mass of the core ranges from 1% to 50% by mass, preferably 2% to 15% by mass, more preferably 3% to 10% by mass.

[0059] The total amount of binding agent F. in relation to the total dry mass of the outer layer(s), ranges from 1% to 30% by mass, preferably 2% to 20% by mass, more preferably 3% to 15% by mass. |0060) Binding agents of component C and component F can be selected from the group consisting of phenoplast resin, aminoplast resin, and organic isocyanate with at least two isocyanate groups, with the use of the same or different binding agents or a binding agent of a mixture of components C and F. preferably different binding agents with a certain preference for phenoplast and aminoplast resins in both cases. The mass ratio in the case of phenoplast or aminoplast resin refers to the solid content of the respective component (determined by evaporating water at 120°C for 2 hours, according to Giinter Zeppenfcld, Dirk Grunwald, Klebstoffe in der Hoiz- und Mobelindustrie, 2<nd>Edition, DRW-Verlag, page 268), while in relation to the isocyanate, more specifically PMDI (polymeric diphenyl methane diisocyanate), it refers to the isocyanate component is controlled. in other words. without solvents or emulsifiers.

[0061] The term "phenoplast" refers to synthetic resins or modified products obtained by condensation of phenol with aldehydes. In addition to unsubstituted phenol, phenol derivatives can also be used in the production of phenoplast resins. These include cresols and other alkylphenols (eg, p-tert-butylphenol, p-tert-octylphenol, and p-tert-nonylphenol), arylphenols (eg, phenylphenol and naphthols), as well as phenol derivatives (such as resorcinol and bisphenol A). The most important aldehyde component is formaldehyde, which is used in various forms, including aqueous solution and solid paraformaldehyde, as well as formaldehyde-yielding compounds. Other aldehydes (for example, acetaldehyde, acrolein, benzaldehyde and furfural) are used to a much lesser extent, as well as ketones. Phenoplast resins can be modified by chemical reaction with methiol or with a phenolic hydroxyl group and/or physical dispersion in a modifying agent (EN ISO 10082). [0062] Preferred Phenoplast resins are phenol aldehyde resins, most preferably phenol-formaldehyde resins. Phenol-formaldehyde resins (also designated as PF resins) are described in the state of the art, for example, in Kunststoff-Handbuch, 2nd Edition, Hanser 1988, volume 10, "Duroplaste", pages 12 to 40.|0063JK-ao aminoplast resin it is possible to apply all aminoplast resins known in the state of the art, especially those known in the production of wood materials. Resins of this type as well as their preparation are described, for example, in Ullmann's Enzvklopadie der technischen Chemie, 4<lh>, revised edition, Verlag Chemie, 1973, pages 403 to 424 "Amino-plaste", and Ullmann's Encvclopedia of Industrial Chemistrv, vol. A2, VCH Verlagsgeselischaft. 1985, pages 115 to 141 "Amino Resins", as well as in M. Dunky, P. Niemz, Holzwerkstoffe und Leime, Springer 2002, pages 251 to 259 (UF resins) and pages 303 to 313 (MUF and UF with a small amount of melamine). In general, they are semi-condensation products of compounds with at least one - optionally partially substituted organic radical - amino group or carbamide group (urea group is also called carboxamide group), preferably carbamide group, preferably urea or melamine and some aldehyde. preferably formaldehyde. Preferred polycondensation products are urea-formaldehyde resins (UF resins), melamine-formaldehyde resins (MF resins) or urea-formaldehyde resins with melamine content (MUF resins), more preferably urea-formaldehyde resins, an example of which is Kaurit® glue produced by BASF SE.

[0064] More specifically, preferred polycondensation products are those in which the molar ratio of aldehyde-optionally partially substituted with organic radicals-amino group and/or carbamide group is between 0.3:1 to 1:1, preferably 0.3:1 to 0.6:1, more preferably 0.3:1 to 0.55:1, very preferably 0.3:1 to 0.5:1. When aminoplast is used in combination with isocyanate, the molar ratio of aldehyde to - optionally partially substituted by some organic radical - amino group and/or carbamide group ranges from 0.3:1 to 1:1. preferably 0.3:1 to 0.6:1, more preferably 0.3:1 to 0.45:1, very preferably 0.3:1 to 0.4:1.

[0065] The indicated aminoplast resins are most often used in liquid form, as a solution of 25% to 90% by mass, preferably 50% to 70% by mass of the strength of the solution, preferably in the form of aqueous solutions, but they can also be used in solid form.

[0066] The solid content of liquid aminoplast resin solutions can be determined according to Giinter Zeppenfeld, Dirk Grunwald, Klebstoffe in der Holz- und Mobelindustrie, 2<mi>Edition, DRW-Verlag, page 268. [0067] The ingredients of binding agent C and binding agent F can be used independently as such - meaning, for example. aminoplast resin or organic isocyanate or PF resin as the sole component of bonding agent C or bonding agent F. Resins in the composition of bonding agents C and F can be used in combination with two or more components of bonding agent C and/or bonding agent F; these combinations preferably contain some aminoplast resin and/or phenoplast resin. |0068] In one preferred embodiment, a combination of aminoplast and isocyanate can be used as binding agent C. In this case, the total amount of aminoplast resin in the binding agent, in relation to the total dry mass of the core ranges from 1% to 45% by mass, preferably 4% to 14% by mass, more preferably 6% to 9% by mass. Total amount of organic isocyanate. preferably oligomeric isocyanate with 2 to 10. preferably 2 to 8 monomer units and on average at least one isocyanal group per monomer unit, more preferably PMDI, in the binding agent C, relative to the total dry mass of the core, ranges from 0.05% to 5% by mass, preferably 0.1% to 3.5% by mass, more preferably 0.5% to 1.5% by mass. [0069] Components D and G can each independently contain different or identical, preferably identical, polymer hardening agents known in the state of the art or their mixtures. These components are most often used if the binding agent C and/or F contain aminoplast or phenoplast resins. These polymer stiffening components are preferably added to the binding agent C and/or F, in the range of, for example, 0.01% to 10% by weight, preferably 0.05% to 5% by weight, more preferably 0.1% to 3% by weight, relative to the total amount of aminoplast resin or phenoplast resin.

[0070] Polymer hardening agents for the aminoplast resin component or for the phenoplast resin component include all chemical compounds of any molecular weight that accelerate or enable polycondensation of the aminoplast resin or phenoplast resin. One very suitable group of polymer curing agents for aminoplast resin or phenolic formaldehyde resin are organic acids, inorganic acids, or acid salts, such as ammonium salts or acid salts of organic amines. The components of this group can also be used in mixtures. Examples are ammonium sulfate or ammonium nitrate or organic or inorganic acids, such as for example. sulfuric acid, formic acid or substances regenerated by acids, such as aluminum chloride, aluminum sulphate or their mixtures. One preferred group of polymer curing agents for aminoplast resins or phenoplast resins are organic or inorganic acids, such as nitric acid, sulfuric acid, formic acid, acetic acid, and polymers containing functional groups of these acids, such as homopolymers or copolymers of acrylic acid or methacrylic acid or malic acid. A phenoplast resin, preferably a phenol-formaldehyde resin, can be hardened by alkylation. The use of a carbonate or hydroxide, such as potassium carbonate or sodium hydroxide, is preferred.

[0071] Further examples of polymer curing agents for aminoplast resins are described in M. Dunky, P. Niemz, Holzwerkstoffe und Leime, Springer 2002, pages 265 to 269, and other examples of curing agents for phenoplast resins, preferably fcnoformaldehyde resins, are described in M. Dunky, P. Niemz, Holzwerkstoffe und Leime, Springer 2002, pages 341 to 352.

(0072) Lignocellulosic materials according to the invention can further contain commercial additives or additives known in the state of the art, in the form of component D and component G, independently of each other, identical or different, preferably identical additives. in an amount of 0% to 10% by mass, preferably 0.5% to 5% by mass, more preferably 1% to 3% by mass. and examples are agents that increase hydrophobicity, such as paraffin emulsions, antifugal agents, formaldehyde scavengers, such as urea or polyamines. for example. flame retardants. 10073] The thickness of lignocellulosic materials according to the invention with expanded plastic particles in the core and with lignocellulosic fibers in the outer layers varies depending on the application and is in the range of 0.5 to 100 mm, preferably in the range of 10 to 40 mm, specifically! 5 to 20 mm. [0074] Expandable plastic particles B are unevenly distributed in the core. This means that the mass ratio X of expanded plastic particles to lignocellulosic particles A in the outer region of the core ("exterior") is different from the mass ratio Y of expanded plastic particles B to lignocellulosic particles A in the inner region of the core ("interior"), in other words, it is greater or less in the outer regions of the core ("outerf') than in the inner regions of the core ("interior"). The inner region of the core is generally separated from the two outer regions of the core by surfaces parallel to by providing a panel. The inner region comprises 20% to 80% by mass, preferably 40% to 60% by mass, more preferably 50% by mass of the total dry mass of the core. In other words, 25% by mass, for example, 25.01:24.99% to 25.99:24.01% by mass, preferably 25.01:24.99% to 25.8:24.2%, more preferably 25.01:24.99% to 25.6:24.4%, more specifically 25.01:24.99% to 25.4:24.6%, or different masses, in relative to the total dry weight of the core, that is, 26:24% to 40:10% by weight, preferably 26:24% to 30:20% by weight. preferably 26:24% to 27:23% by mass, more specifically, 26:24% to 26.5:23.5% by mass. In total, the inner region and the two outer core regions make up 100% of the mass. To determine the ratio X of expanded particles B to lignocellulosic particles A in the ext in the core region, all expanded particles B and all lignocellulosic particles A located in the two outer regions are taken into account. In this case the ratio X', which describes the ratio of plastic particles B to lignocellulosic particles A in one of the two outer regions, may differ from or be the same as the ratio X", which describes the ratio in the remaining two outer regions.

[0075] In the material according to the invention, the ratio Z between the mass fraction X of the expanded plastic particles in the outer regions of the core ("exterior") and the mass fraction Y of the expanded plastic particles to the lignocellulosic particles in the inner region of the core ("interior") is 1.05:1 to 1000:1, preferably 1.1:1 to 500:1, more preferably 1.2:1 to 200:1. In a further embodiment, this ratio Z is 0.001:1 to 0.95:1, preferably 0.002:1 to 0.9:1, more preferably 0.005:1 to 0.8:1.

[0076] Unequal distribution of plastic particles B can be achieved as follows: |0077| It is possible to prepare a number of mixtures of components A, B, C and D with different mass fractions of components A and B. These mixtures can be dispersed one after the other. In this case, it is necessary to achieve that mixtures with different mass fractions of components A and B are slightly mixed or not mixed at all. In this way, an unequal distribution of expanded plastic particles in the core of the lignocellulosic material is achieved. In this context, both wood particles A and plastic particles B can be pre-separated into different fractions by screening. Each of the mixtures may contain different fractions of wood particles A and/or plastic particles B.

[0078] In the following embodiment, the unequal distribution of plastic particles B in the core can be achieved by separate scattering. In this case, the scattering takes place in a way that ensures that the spheres accumulate either in the outer regions or in the inner regions of the core, depending on the size and/or mass. This is achieved, for example, by scattering the mixtures A, B, C. D using a triage system. In one preferred embodiment, this system is equipped with a screen system with openings of different sizes that are placed symmetrically like a mirror. It is especially desirable that the support on which the material for the lower outer layer is located is placed under the scattering means in which the triage system is located, so that at the beginning of the scattering unit (in the production sense) there are sieves with openings of small size, and that the size of the openings on the sieves progressively increases towards the center of the scattering unit and then decreases towards the end of the scattering unit. Such an arrangement of the sieves allows small lignocellulosic particles to enter the outer regions of the core, closer to the outer layer, and large lignocellulosic particles to enter the inner regions of the core. At the same time, small plastic particles enter the outer regions of the core, those closer to the outer layer, while large plastic particles enter the inner region of the core. Depending on the size distribution of lignocellulosic particles and plastic particles, different mass ratios of lignocellulosic particles A to plastic particles B are achieved in this way. A scattering unit of this type is described in EP-B-1140447 and DE-C-19716130. [0079] For example, a unit for dispersing lignocellulosic particles may contain two silos for measurement, where there are different rakes in each. The measuring silos are filled with the base material, which consists of particles A of different sizes and components B, C and D ("core mixture") (eg. as described). On the lower surface of each of the two silos there is a belt that extends along two bent rollers and which, together with the discharge roller, form a unit for releasing the core mixture. Underneath each roller there may be a continuous sanding belt which moves over the rollers and the lower surface of which may be passed over the triage device with openings of different sizes, thereby forming different sections of the triage device. Together with the sanding belt, the triage device is a means of fractionation by which lignocellulosic particles A and plastic particles B from the core mixture can be separated based on their particle size. The sections of the triage device can be arranged so that the fine lignocellulosic particles A and/or plastic particles B are scattered in those regions of the scattering unit that lie outside the transport direction of the net, on the lower outer layer, while the larger lignocellulosic particles A and/or plastic particles B are scattered over the inner regions of the fractionation means. to the outer layer (see for details, EP-B-1140447).

[0080] According to the following preferred embodiments of the invention, at least on one part of the separation section there is an abrasive element that rests on the screen surface. so that when the separation section moves, the abrasive element grinds over the screen surface. The abrasive element moving under low pressure over the screen surface of each separation section or some separation sections further enhances the cleaning effect achieved when the separation section is moved over the screen surface. At the same time, the abrasive element strengthens the force acting on the particles in the direction normal to the surface of the screen, thus producing an increase in flow. The means of transport is preferably designed in the form of a sanding belt, more specifically. as a continuous conveyor belt for sanding. In this way, a simple and inexpensive configuration of the means of transport is obtained. In this case, the abrasive belt is preformed for the particles over at least one subregion in a direction normal to the screen surface. thus allowing the particles to fall from the top of the silo and through the feed unit to come on the sanding belt to the surface of the screen. This reduces the need for a kit and forged configuration of the power supply unit. According to the following suitable form of the invention, the sanding belt contains a guide, specifically plate guides which are placed at regular distances on a continuous support element in the form of a chain or belt. In this case, the support element can be placed centrally on the steering wheel. It is possible to place different support elements, more specifically two chain or belt support elements, so that each is attached in the region laterally outside the edges of the steering wheel. This increases the stability of the sanding belt designed in accordance with the invention. It is desirable that the controls are fixed to the support element or support elements so that they can be dismantled and/or are hermetically sealed. on the one hand, the used steering wheels are optimally adapted to the set and, on the other hand, damaged steering wheels are replaced with new ones. According to the following preferred embodiment of the invention, the abrasive elements are formed from one part of the steering wheel. In this way, the design of the screen according to the invention can be economical, because separate components of the abrasive elements are not required. In particular, at least in the parts that form the abrasive elements, the handlebars are elastic and made of hard rubber, for example. This allows the abrasive elements to adapt to the screen surface. enabling thus. Even in the case of some irregularities in the sieve surfaces. that the abrasive elements move along the screen surface with sufficient pressure over their entire width, as well as along all possible movements. According to the next preferred embodiment, the controls are made to be abrasive resistant, at least in the parts that form the abrasive elements and which have an abrasive resistant coating, such as a Teflon layer, for example. The parts of the steering wheel that form the abrasive elements can be designed integrally with the steering wheel or they can be designed as separate components. When abrasive elements are designed as separate components, they should preferably be positioned so that they can be removed from the steering wheel so that they can be replaced in the event of damage. According to the next suitable embodiment of the invention, the controls, at least in the part that forms the abrasive elements, are formed from a hydro-repellent, non-adherent material. This allows particles moistened with the binding agent to become stuck in the guide, which could reduce the capacity of the separation section. According to the following preferred embodiment of the invention, the sieves contain sieve zones, specifically two sieve zones, with openings of different sizes. In this way, particles of different sizes are separated by passing through openings of different sizes. In this case, specifically, the sieve zones are arranged one behind the other along the direction of movement of the separation section moving over the sieve surface. and preferably the sieve openings in the zones placed in the direction of movement of the separation section are larger than the sieve openings in the zones placed opposite to the direction of movement. This allows that as they move along the sieve zone, particles of small diameter pass through the sieves first, while in the next zone, larger particles pass through which can pass through the openings of the next size. Depending on the number of sieve zones and the size of the sieve openings, a suitable separation is achieved. Separated particles can fall, according to the size of the sieve, into collectors for collecting particles of different sizes, or for example. they can fall on the conveyor belt placed under the sieve and in this way it is possible to obtain a distribution network of particles of different sizes and densities.

[0081] According to the following embodiment of the invention, the continuous sanding belt is guided by means of two rollers so that the lower section of the belt goes directly over the surface of the sieve while the upper surface of the belt goes at a certain distance from the surface of the sieve. and in both cases parallel to the sieve surface. In this way, the invention provides a particularly compact design. In this case, it is desirable that at least one end of the sanding belt, specifically on the part with the rollers, has a device for collecting loose particles. These particles can be foreign bodies in the material, such as nails or screws. for example; alternatively, this material may be aggregates or particles whose size exceeds the maximum specified sieve size and which are ejected and picked up as the sieve is opened. even the biggest ones wouldn't choke. According to the next preferred form of execution, in the part between the upper and lower sections of the belt, there is a middle base over which the guides pass, with their ends directed against the parts that form the abrasive elements, in other words. when the parting part is moved these ends grind the central base. Thanks to this form of execution, the material that is applied from the measuring silos via the feeding unit to the central base can be brought in a controlled manner to a precisely defined place between the rollers. In this case, according to one preferred embodiment, the central base can extend from one roller in the direction of movement of the upper part of the tape towards the opposite roller; between this second roller and the end of the central base located opposite the second roller, a region is formed that is passable for particles in the direction normal to the screen surface. Specifically, when this region is formed by a further sieve with relatively large openings, it is possible in this case that there is a previous deposition of foreign bodies or particles with a diameter larger than the largest openings. Only those particles that pass through the more distant sieve fall on the sieves, over which they move thanks to the moving means. According to the next preferred embodiment, there are two grinding belts placed one behind the other in the longitudinal direction, and the grinding belts are arranged in such a way that they are like a mirror image. In this case, a distribution unit in the form of a mobile distributor is placed under the feeding unit of the measuring silo, and it can be used to deliver the particles taken from the silo through the feeding unit in two grinding belts, alternately. This design enables, starting from one measuring silo, the distribution of particles in two different sanding belts. Especially when the two grinding belts are driven in different directions, so that the two upper sections of the belt can be moved in a mutually different way, and when there is a central base between the upper and lower sections of the belt, in the manner previously described, it is possible for the particles delivered by the distribution means to the respective central bases to be transported to the ends of the grinding belts located in different directions, where they are applied to the sieves placed under the grinding belts. If the sieves with the appropriate opening size are correctly selected, especially when the size of the opening increases in the direction of movement of the lower section of the belt, the core material can be formed by moving the belt placed under the sieve and on which the lower outer layer has already been dispersed. The formation of the core material takes place by the fact that fine lignocellulosic particles A and/or plastic particles B are collected in the outer layers of the core, while coarser lignocellulosic particles A and/or plastic particles B are collected in inner core layer. Instead of a distribution means, it is possible, for example, to have two measuring silos with two grinding belts that are supplied with particles. In all embodiments, the sieves and/or other sieves are preferably designed as oscillating sieves or vibrating shaker sieves. In this case, the material supplied to the screen becomes looser. which means that finer particles and then medium-sized particles quickly pass to and through the sieve openings (see for details, DE-C-197 16 130). [0082|The next preferred form of execution is the application of a roller spreading system with specially profiled rollers (roller screens). In this case, it is preferable to choose a symmetrical construction, which means that small lignocellulosic particles A and/or small plastic particles B enter the outer regions of the core, those closer to the outer layer, while large lignocellulosic particles A and/or large plastic particles B enter the inner region of the core. One particularly suitable embodiment is the application of one or more ClassiFormer™ devices. Suitable, for example, is the Classiformer CC from Dieffenbacher, which has a symmetrical construction. Alternatively, it is possible to apply two Classiformers C, arranged opposite each other. [0083] Lignocellulosic materials, such as for example wood-based materials, are a cheap and good alternative to solid wood and have become very important, especially in the manufacture of furniture, laminate flooring and construction materials. As the most common starting material, wood particles of different densities are used, for example, wood sawdust and shavings and wood fibers from different types of trees. These wood particles are compressed with natural and/or synthetic binding agents and optionally with the addition of other additives, in order to obtain wood-based materials in the form of boards or strips. |0084|Light wood-based materials are very important for the following reasons: products obtained from light wood-based materials are easily used by clients, in terms of packaging, transport, unpacking or in furniture construction. Light wood-based materials have lower transport and packaging costs, and also possible savings on material costs in the production of these materials. Lightweight wood-based materials, when used for transportation purposes, can reduce energy consumption in those forms of transportation. Also. the application of lightweight wood-based materials enables more cost-effective production, for example. decorative parts with a large consumption of material, relatively thick work surfaces or side panels in kitchens.

[0085] There are numerous applications, for example in the segments of bathroom and kitchen furniture or in interiors, where there is a need for light and cheap lignocellulosic materials with improved mechanical properties, for example, increased resistance to bending and pulling out screws. In addition, the outer surface of these materials is of high quality, which enables the application of covering layers, for example, paint or varnish, with good properties.

Examples

1. Production of expanded polymer particles

[0086] Expandable polystyrene Polystyrene Kaurit® Light 200 from BASF SE served as starting material. Polystyrene Particles were treated with steam and foam until a specific density of 50 g/l was reached in the vat. The expanded polymer particles obtained in this way (component B) were stored at room temperature in a non-hermetic textile bag for 7 days before further use.

2. Production of wooden materials

[0087] Three different mixtures of starting materials were produced for each wood panel.

Mixture 1: Components E, F, G for cover layers

Mixture 2: Components A, B, C, D for the outer core region

Mixture 3: Components A, B, C, D for the inner core region

[0088] Component B is excluded from comparative example 1, that is, mixtures 2 and 3 contain in that case only components A, C and D. For comparative example 2 and example 3, according to the invention, mixtures 2 and 3 are identical. In comparative examples 1 and 2, mixture 1 contains wood shavings as component E, and in all other examples, wood fibers. [0089] All mixtures were produced using a laboratory mixer, with the solids first poured and then mixed. The liquid ingredients are pre-mixed in a bowl and then sprayed.

[0090] For mixture I, use a finely divided cover layer of spruce shavings with a moisture content of 5.9% or wood fibers with a moisture content of 2.8% (component E). |0091) For mixtures 2 and 3, use the central layer of wood chips, made of wood chips with a moisture content of 3.2 % (component A), [0092] Kaurit® glue 347. with a solid content of 67%, produced by BASF SE was used as a binding agent (components C and F). For Mixture 1, 40 parts by weight of water and 1 part by weight of 52% ammonium nitrate solution (in both cases relative to 100 parts by weight of Kaurite Glue 347) were added to the adhesive prior to addition to the mixture solids. For mixtures 2 and 3, 4 parts by mass of 52% ammonium nitrate solution (from 100 parts by mass of Kaurit glue 347). was added to the adhesive prior to application to the solid ingredients of the mixture.

[0093] For cover layers (mixture 1). The amount of glue mixture is set so that 10% is obtained by adding glue, that is. 10 parts by mass of the plug (relative to the solid substance) per 100 parts by mass of E (relative to the solid substance).

(0094) For the core (and the outer region - mixture 2 and for the inner regions of the core - mixture 3), the amount of glue was adjusted to obtain a percentage of glue of 8.0%, ie. 8.0 parts by mass of glue (relative to solids). per 100 parts by mass of the mixture of A and B (relative to the solid substance).

[0095] The mixtures were then placed one over the other in layers in 30 x 30 cm moulds, in order to obtain a base of wood material with a symmetrical structure made up of 5 layers (in order, mixture I. mixture 2, mixture 3. mixture 2. mixture 1). The quantities were chosen so that the mass ratio of the layers (in relation to the dry substance) was 15.5:20.5:28:20.5:15.5.

[0096] In all examples containing component B, the mass ratio of the total amount of component B in the composition of all three inner layers to the total amount of component A in all three inner layers is the same (relative to the solid substance). [0097|The total mass of the wooden material substrate was chosen so as to obtain the desired density at a given thickness of 18.5 mm at the end of the pressing process.

[0098] The base of the wood material is then cold compressed and pressed with a hot press. In this way, a thickness of 16 mm is achieved. The pressing temperature in all cases is 210°C, and the pressing time is 210 seconds.

3. Examination of wooden materials

3.1 Density

J0099|Density determination was carried out 24 hours after production, in accordance with EN 1058.

3.2 Transverse tensile strength

[0100] Determination of transverse tensile strength was carried out in accordance with EN 319.

3.3 Bending resistance E

[01011 Determination of resistance to bending and bending was carried out in accordance with DIN EN 310.

3.4 Resistance to bolt removal

[0102] The determination of the resistance to the removal of screws was carried out in accordance with DIN EN 320. Only the surface resistance of the material to the removal of screws was measured.

3.5 Resistance to peeling

[0103] Determining the resistance to peeling, as a measure of surface quality, was carried out in accordance with DIN EN 311.

Examples

[0104|Examples 1 and 2: Comparative examples using shavings in the cover layer (with and without expanded polymer particles in the core) Examples 3 to 7: Examples according to the invention

Claims (7)

1. Lignocellulosic material composed of a core and two outer layers, which in the core contains A) 30% to 98% of the mass of lignocellulosic particles; B) 1% to 25% by mass of expanded plastic particles with a specific density in the range of 10 to 150 kg/m3, C) 1% to 50% by mass of one or more binding agents selected from the group consisting of phenoplast resin, aminoplast resin and organic isocyanate with at least two isocyanate groups, and D) 0% to 30% by mass of additives and in the outer layers E) 70% to 99% by mass of lignocellulosic fibers, F) 1% to 30% by mass of one or more binding agents selected from the group consisting of phenoplast resin, aminoplast resin and organic isocyanate with at least two isocyanate groups, and G) 0% to 30% by mass of additives, indicated by the fact that the expanded plastic particles B are unevenly distributed in the core, which means that the mass ratio X of expanded plastic particles B to lignocellulosic particles A in the outer regions of the core is different from of the mass ratio Y of expanded plastic particles B to lignocellulosic particles A in the inner region of the core. 2. Lignocellulosic material with a core and two outer layers, whose core consists of A) 30% to 98% of the mass of lignocellulosic particles; B) 1% to 25% of the mass of expanded plastic particles with a specific density in the range from I to 150 kg/m3. C) 1% to 50% by weight of one or more binding agents selected from the group consisting of phenoplast resin, aminoplast resin and organic isocyanate with at least two isocyanate groups, and D) 0% to 30% by weight of additives and the outer layers consist of E) 70% to 99% by weight of lignocellulosic fibers, F) 1% to 30% by weight of one or more binding agents selected from the group consisting of phenoplast resin, aminoplast resin and organic isocyanate with at least two isocyanate groups, and G) 0% to 30% by weight of additives, indicated by the fact that the expanded plastic particles B are unevenly distributed in the core, which means that the mass ratio X of expanded plastic particles B to lignocellulosic particles A in the outer regions of the core is different from the mass ratio Y of expanded plastic particles B to lignocellulosic particles A in the inner region of the core. 3. A method of producing lignocellulosic material according to requirements I and 2, by mixing components E, F and G for the outer layers and components A, B, C and D for the core, indicated by the fact that the material] for the core is dispersed in such a way as to form an unequal mixture of components A and B. 4. The method of production of lignocellulosic material according to claim 3, characterized by the fact that an unequal mixture of components A and B is obtained by alternate scattering of mixtures with different proportions of components A to B. 5. A process for the production of lignocellulosic material according to any one of claims 3 to 4, characterized in that the unequal mixture of components A and B is obtained by dispersing mixtures containing A, B, C and D separately. 6. The procedure for applying lignocellulosic material in accordance with any of the requirements and to 2, in the construction of furniture, for laminate floors and for construction materials. 7. Application to lignocellulosic material according to any of claims 1 to 2, for the production of panels for furniture construction, for laminate flooring and for construction materials.