EP2464691A1

EP2464691A1 - Light lignocellulosic materials having good mechanical properties

Info

Publication number: EP2464691A1
Application number: EP10739608A
Authority: EP
Inventors: Frank Braun; Olaf Kriha; Klaus Hahn; Benjamin Nehls; Maxim Peretolchin; Stephan WEINKÖTZ
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2009-08-13
Filing date: 2010-08-02
Publication date: 2012-06-20
Also published as: CA2769894A1; CN102471587A; WO2011018372A1; BR112012003295A2; JP2013501647A; US20120141772A1; NZ598089A; AU2010283880A1; AU2010283880B2

Abstract

The invention relates to a method for producing a light lignocellulosic material having an average density in the range of 200 to 600 kg/m3, and comprising, on basis of the lignocellulosic material: A) 30 to 95 wt % of lignocellulose particles; B) 1 to 25 wt % of expanded plastic particles having a bulk density in the range of 10 to 100 kg/m3; C) 3 to 50 wt % of a binding agent, selected from the group of aminoplast resin, phenol formaldehyde resin, and organic isocyanate having at least two isocyanate groups; and optionally D) additives are mixed and then pressed under increased temperature and increased pressure, characterized in that the expanded plastic particles are obtained from expandable plastic particles having a content of propellant in the range of 0.01 to 4 wt % relative to the expandable plastic particles.

Description

The present invention relates to a process for producing a light lignocellulose-containing substance having an average density in the range from 200 to 600 kg / m ³ , in which, in each case based on the lignocellulose-containing substance:

A) 30 to 95% by weight of lignocellulose particles;

B) from 1 to 25% by weight of expanded plastic particles having a bulk density in the range from 10 to 100 kg / m ³ ,

C) 3 to 50 wt .-% of a binder selected from the group consisting of aminoplast resin, phenol-formaldehyde resin and organic isocyanate having at least two isocyanate groups and optionally

D) mixing additives and then pressed under elevated temperature and under elevated pressure, characterized in that the expanded plastic particles of expandable plastic particles with a content of blowing agent in the range of 0.01 to 4 wt .-%, based on the expandable Kunstoffteilchen to be obtained.

The sum of components A), B), C) and optionally D) adds up to 100%.

Furthermore, the present invention relates to the use of expandable plastic particles as defined in the claims, a method for producing a multilayer lignocellulosic material as defined in the claims and the use of the light lignocellulose-containing materials according to the invention and the multilayer lignocellulosic material according to the invention as defined in the claims

Lignocellulosic materials, for example wood-based materials, in particular multilayer wood-based materials, are a cost-effective and resource-saving alternative to solid wood and have gained great importance in particular in furniture construction, in laminate flooring and as building materials. The starting materials used are wood particles of different strengths, eg. As wood chips or wood fibers from different woods. Such wood particles are usually compressed with natural and / or synthetic binders and optionally with the addition of further additives to plate-like or strand-shaped wood materials. In order to achieve good mechanical properties of the wooden materials, these are produced with a density of about 650 kg / m ³ and more. Users, especially private individuals Consumers, wood materials of this density or the corresponding parts, such as furniture, often too heavy.

The industrial demand for lightweight wood-based materials has therefore risen steadily in recent years, especially since pick-up furniture has gained in popularity. Furthermore, the rising price of oil, which leads to a constant increase in, for example, transport costs, is causing increased interest in lightweight wood-based materials.

In summary, lightweight wood-based materials are of great importance for the following reasons:

Lightweight wood-based materials result in easier handling of the products by the end customer, for example when packing, transporting, unpacking or constructing the furniture.

Light wood-based materials lead to lower transport and packaging costs, and material costs can be saved in the production of lightweight wood-based materials. Light wood-based panels can, for example, when used in means of transport lead to lower energy consumption of these means of transport. Further, using lightweight wood-based materials, for example, costly decorative parts such as thicker worktops and kitchen cheeks that are currently in vogue can be offered more cheaply.

There are many proposals in the state of the art for reducing the density of wood-based materials.

As light wood-based materials, which are available by constructive measures, are, for example, tube chipboard and honeycomb panels to call. Due to their special properties, tube chipboards are mainly used in the manufacture of doors as an inner layer.

A disadvantage of the honeycomb panel, for example, the too low Schraubenauszugswi- resistance, the difficulty attaching fittings and the difficulties in edging.

Furthermore, there are proposals in the prior art to reduce the density of the wood materials by adding glue or to the wood particles.

In CH 370229 light and simultaneously pressure-resistant molding materials are described, which consist of wood shavings or fibers, a binder and a filler consist of porous plastic. To produce the molding materials, the wood chips or fibers are mixed with binders and expandable or partially foamable plastics, and the resulting mixture is pressed at elevated temperature. The blowing agent content of the filler polymers is not reflected by CH 370229.

WO 02/38676 describes a process for the preparation of light products, in which 5 to 40 wt .-% foamable or already foamed polystyrene having a particle size of less than 1 mm, 60 to 95 wt .-% lignocellulose-containing material and binder mixed and at elevated Temperature and elevated pressure are pressed to the finished product. The propellant content of the filler polymer WO 02/38676 does not express.

In WO 2008 / 046890A (BASF SE), WO 2008/046891 A (BASF SE) and

WO 2008/046892 A (BASF SE) describes, inter alia, light wood-containing substances which include, for example, wood chips or fibers, a binder and a binder

Filler serving porous plastic. For the production of wood-containing substances, for example, the wood chips or fibers are mixed with binders and foamable or partially foamable plastics, and the resulting mixture is compressed at elevated temperature. WO 2008/046890 A, WO 2008/046891 A and WO 2008/046892 A are silent on the blowing agent content of the filler polymers or their precursors.

The disadvantage of the prior art is summarized in that the precursor polymers used for the preparation of the foamed fillers contain relatively large amounts (usually more than 5 wt .-% based on the precursor polymers) of propellant, for example pentane (mixtures). Most propellants, such as pentane, are highly flammable.

This has the disadvantage that complex technical measures must be taken to the formation of flammable or even explosive propellant / air mixtures in the production of light lignocellulosic, such as wood-containing substances or equivalent, usually multilayer, Lignocellulosewerkstof- fe, for example Wood materials, to prevent. Usually, the expanded plastic particles, for example polystyrene, with pentane (mixtures) as blowing agent, stored for several days in special silos with ventilation, so that the blowing agent, such as pentane (mixture), can escape. This relatively long storage prevents the continuous production of the light lignocillulose-containing, for example wood-containing, substances or corresponding, generally multilayer, lignocellulosic materials, for example wood-based materials, and can lead to a reduction of the production capacity for the light lignocellulose-containing substances. For example, wood-containing materials or corresponding, usually multilayer, lignocellulosic materials, such as wood materials lead.

The object of the present invention was to show plastic particles for light lignocellulose-containing substances and light lignocellulosic materials, which can be prepared and handled without risk of fire and which can be expanded controlled with relatively simple methods, but they lignocellulose-containing, preferably wood-containing substances and Lignocellulose materials, preferably wood materials, lower density lead, with at least equally good mechanical strength and good processing properties, for example, Bekant- availability, such as those of the prior art.

The mechanical strength can be determined, for example, by measuring the transverse tensile strength according to EN 319.

The TKH-Merkblatt (Technical Commission on Wood Adhesives in the Industrial Adhesives e.V.) of January 2006, Table 10 can be used to assess the edgebandability or sticking of edges on chipboard. Furthermore, the swelling value of the light lignocellulosic materials, preferably wood-based materials, should not be adversely affected by the reduced density.

The object was achieved by a process for producing a light lignocellulose-containing substance having an average density in the range from 200 to 600 kg / m ³ , in which, in each case based on the lignocellulose-containing substance:

A) 30 to 95% by weight of lignocellulose particles;

B) 1 to 25% by weight of expanded plastic particles having a bulk density in the range of 10 to 100 kg / m ³ ;

D) mixing additives and then pressed under elevated temperature and under elevated pressure, characterized in that the expanded plastic particles of expandable Kunstoffteilchen having a content of blowing agent in the range of 0.01 to 4 wt .-%, based on the expandable plastic particles , to be obtained. The terms lignocellulose, lignocellulose particles or lignocellulose-containing substance are known in the art. Lignocellulosic material, lignocellulosic particles or lignocellulosic particles are, for example, straw or wood parts, such as wood plies, wood strips, wood chips, wood fibers or wood dust, wood chips, wood fibers and wood dust being preferred. The lignocellulose-containing particles or lignocellulose particles may also be derived from wood fiber-containing plants, such as flax, hemp.

Starting materials for wood parts or wood particles are usually foundry woods, industrial lumber and used wood as well as wood fiber-containing plants. The preparation of the desired lignocellulose-containing particles, for example wood particles, by known methods, see for example M. Dunky, P.

Niemt, Holzwerkstoffe und Leime, pp. 91-156, Springer Verlag Heidelberg, 2002.

Preferred lignocellulose-containing particles are wood particles, particularly preferably hollow fibers, as used for the production of MDF and HDF boards.

Highly suitable lignocellulose-containing particles are also flax or hemp particles, particularly preferably flax or hemp fibers, as can be used for the production of MDF and HDF boards.

The lignocellulosic, preferably wood-containing substance may contain the usual small amounts of water (in a usual small fluctuation range); This water is not included in the weight of the present application. The weight specification of the lignocellulose particles, preferably wood particles, refers to lignocellulose particles which are dried in a conventional manner known to the person skilled in the art, preferably wood particles.

With regard to the aminoplast component in the binder, the weight specification of the binder relates to the solids content of the corresponding component (determined by evaporation of the water at 120 ^° C., within 2 hours, for example, Günter Zeppenfeld, Dirk Grunwald, Klebstoffe in der Wood and furniture industry, 2nd edition, DRW-Verlag, page 268) and with regard to the isocyanate, in particular the PMDI, on the isocyanate component per se, that is, for example, without solvent or emulsifier.

The light lignocellulose-containing, preferably wood-containing substances according to the invention have an average density of 200 to 600 kg / m ³ , preferably 200 to 575 kg / m ³ , particularly preferably 250 to 550 kg / m ³ , in particular 300 to 500 kg / m ³ .

The transverse tensile strength of the light lignocellulose-containing, preferably wood-containing substances according to the invention or preferably the multi-layered The lignocellulosic materials, more preferably multilayer wood-based materials, is generally in the range from 0.1 N / mm ² to 1.0 N / mm ² , preferably 0.3 to 0.8 N / mm ² , particularly preferably 0.4 to 0 , 6 N / mm ² . The determination of the transverse tensile strength is in accordance with EN 319.

Suitable multilayered lignocellulose materials are all materials which are produced from lignocellulose veneers, preferably wood veneers, preferably with a mean density of the wood veneers of 0.4 to 0.85 g / cm ³ , for example veneer boards or plywood boards or laminated veneer lumber ( LVL).

As multilayered lignocellulosic materials, preferably multilayer wooden materials, particularly preferably all materials come into consideration, which are made of lignocellulos chips, preferably wood shavings, preferably with an average density of wood chips from 0.4 to 0.85 g / cm ³ , for example chipboard or OSB boards, as well as wood fiber materials such as LDF, MDF and HDF boards. Particleboard and fiberboard, in particular chipboard, are preferred.

The average density of the lignocellulose particles, preferably the wood particles, of the component A) is generally 0.4 to 0.85 g / cm ³ , preferably 0.4 to 0.75 g / cm ³ , in particular 0 , 4 to 0.6 g / cm ³ .

For the production of wood particles any wood species comes into question; For example, spruce, beech, pine, larch, linden, poplar, ash, chestnut or fir wood are very suitable; spruce and / or beech wood, in particular spruce wood, are preferred.

The dimensions of the lignocellulose particles, preferably wood particles, are not critical and, as usual, depend on the lignocellulose material to be produced, preferably wood-based material, for example the abovementioned wood-based materials, such as chipboard or OSB.

Component B) are expanded plastic particles, preferably expanded thermoplastic plastic particles.

Such expanded plastic particles are usually obtained as follows: Compact plastic particles which contain an expansible medium (often also called "blowing agent") are expanded by the action of heat energy or pressure change (often also referred to as "foamed"). Here, the propellant expands, the particles increase in size and cell structures arise.

The expansion can be carried out in one or more stages. Usually In the single-stage process, the expandable plastic particles are readily expanded to the desired final size.

In general, in the multi-stage process, the expandable plastic particles are first expanded to an intermediate size and then expanded in one or more further stages over a corresponding number of intermediate sizes to the desired final size.

The abovementioned compact plastic particles, also referred to herein as "expandable plastic particles", as a rule, contain no cell structures, in contrast to the expanded plastic particles.

Suitable polymers which underlie the expandable or expanded plastic particles are all polymers, preferably thermoplastic polymers, which can be foamed. These are known to the person skilled in the art.

Well-suited such polymers are, for example, polyketones, polysulfones, polyoxymethylene, PVC (hard and soft), polycarbonates, polyisocyanurates, polycarbodiimides, polyacrylimides and polymethacrylimides, polyamides, polyurethanes, aminoplast resins and phenolic resins, styrene homopolymers (also referred to below as "polystyrene"). or "styrene polymer"), styrene copolymers, C 2 -C 10 -olefin homopolymers, C 2 -C 10 -olefin copolymers and polyesters. For the preparation of said olefin polymers it is preferred to use the 1-alkenes, for example ethylene, propylene, 1-butene, 1-hexene, 1-octene. The expanded plastic particles of component B) have a bulk density of from 10 to 100 kg / m ³ , preferably from 15 to 90 kg / m ³ , particularly preferably from 20 to 80 kg / m ³ , in particular from 40 to 80 kg / m ³ .

The bulk density is usually determined by weighing a volume filled with the bulk material.

Expanded plastic particles B) are generally used in the form of spheres or beads having an average diameter of advantageously 0.25 to 10 mm, preferably 0.4 to 8.5 mm, in particular 0.4 to 7 mm.

Expanded plastic particle beads or beads B) advantageously have a small surface area per volume, for example in the form of a spherical or elliptical particle. The expanded plastic particle balls B) are advantageously closed-cell. The open cell density according to DIN-ISO 4590 is usually less than 30%. If component B) consists of different types of polymers, ie polymer types which are based on different monomers (for example polystyrene and polyethylene or polystyrene and homopolypropylene or polyethylene and homo-polypropylene), these may be present in different weight ratios, which, however, according to the current state of the art Knowledge, not critical.

In addition, the polymers, preferably the thermoplastics which underlie the expandable or expanded plastic particles B), may contain additives, for example UV stabilizers, antioxidants, coating compositions, hydrophobizing agents, nucleating agents, plasticizers, flame retardants, soluble and insoluble inorganic and / or organic compounds Dyes, pigments, and athermane particles, such as carbon black, graphite or aluminum powder, are added together or spatially separated as additives. For expanding the expandable plastic particles it is possible to use all blowing agents known to the person skilled in the art, for example aliphatic C 3 - to C 10 -hydrocarbons, such as propane, n-butane, isobutane, n-pentane, isopentane, neopentane-cyclo-pentane and / or hexane and its isomers, Alcohols, ketones, esters, ethers or halogenated hydrocarbons.

The content of blowing agent in the expandable plastic particles is in the range of 0.01 to 4 wt .-%, preferably 0.1 to 4 wt .-%, particularly preferably 0.5 to 3.5 wt .-%, each based on the propellant-containing expandable plastic particles. It is preferable to use polystyrene and / or styrene copolymer as the only plastic particle component in component B).

Such polystyrene and / or styrene copolymer can be prepared by all known in the art polymerization process, see, for. Ullmann's Encyclopedia, Sixth Edition, 2000 Electronic Release or Kunststoff-Handbuch 1996, Volume 4 "Polystyrene", pages 567 to 598.

The production of the expandable polystyrene and / or styrene copolymer is generally carried out in a conventional manner by suspension polymerization or by extrusion.

In the suspension polymerization, styrene, optionally with the addition of further comonomers in aqueous suspension, is polymerized in the presence of a customary suspension stabilizer by means of free-radical-forming catalysts. The blowing agent and, if appropriate, further additives can be introduced during the polymerization or added to the batch in the course of the polymerization or after the end of the polymerization. The obtained peribular, impregnated with propellant, expandable styrene polymers are separated after the polymerization from the aqueous phase, washed, dried and sieved.

In the extrusion process, the blowing agent is mixed for example via an extruder in the polymer, conveyed through a nozzle plate and granulated under pressure to particles or strands.

As propellants for the preparation of the expandable polystyrene and / or styrene copolymer, it is possible to use all blowing agents known to the person skilled in the art and already mentioned above, for example aliphatic C 3 - to C 10 -hydrocarbons, such as propane, n-butane, isobutane, n-pentane, Isopentane, neopentane, cyclo-pentane and / or hexane and its isomers, alcohols, ketones, esters, ethers or halogenated hydrocarbons. Preferably, the blowing agent is selected from the group consisting of n-pentane, isopentane, neopentane and cyclopentane. Particular preference is given to using a commercial pentane isomer mixture of n-pentane and isopentane.

The content of blowing agent in the expandable polystyrene or styrene copolymer is in the range of 0.01 to 4 wt .-%, preferably 0.1 to 4 wt .-%, particularly preferably 0.5 to 3.5 wt .-%, each based to the propellant-containing expandable polystyrene or styrene copolymer.

The content of C3- to Cio-hydrocarbons as blowing agent in the expandable polystyrene or styrene copolymer is in the range from 0.01 to 4 wt .-%, preferably 0.1 to 4 wt .-%, particularly preferably 0.5 to 3, 5 wt .-%, each, based on the propellant-containing expandable polystyrene or styrene copolymer.

The content of blowing agent selected from the group consisting of n-pentane, isopentane, neopentane and cyclopentane, in the expandable polystyrene or styrene copolymer is in the range of 0.01 to 4 wt .-%, preferably 0.1 to 4 wt. %, particularly preferably 0.5 to 3.5 wt .-%, each, based on the propellant-containing expandable polystyrene or styrene copolymer. The content of propellant selected from the group consisting of n-pentane, isopentane, neopentane and cyclopentane in the expandable polystyrene is in the range of 0.01 to 4 wt .-%, preferably 0.1 to 4 wt .-%, particularly preferred 0.5 to 3.5 wt .-%, each, based on the propellant-containing expandable polystyrene. The styrene polymers or styrene copolymers described above have a relatively low content of blowing agent. Such polymers are also referred to as "low-blowing agents." A well-suited process for the production of propellant Expandable polystyrene or styrene copolymer is described in US 5,112,875, which is incorporated herein by reference.

Furthermore, additives, for example UV stabilizers, antioxidants, coating compositions, water repellents, nucleating agents, plasticizers, flame retardants, soluble and insoluble inorganic and / or organic dyes, pigments, and athermanous particles, such as carbon black, can be added to the styrene polymers or styrene copolymers. Graphite or aluminum powder, are added together or spatially separated as additives.

As described, styrene copolymers can also be used. These styrene copolymers advantageously have at least 50% by weight, preferably at least 80% by weight, of copolymerized styrene. As comonomers come z. B. α-methyl styrene, nuclear halogenated styrenes, acrylonitrile, esters of acrylic or methacrylic acid of alcohols having 1 to 8 carbon atoms, N-vinylcarbazole, maleic acid (anhydride),

(Meth) acrylamides and / or vinyl acetate into consideration.

Advantageously, the polystyrene and / or styrene copolymer in copolymerized form contain a small amount of a chain splitter, d. H. a compound having more than one, preferably two, double bonds, such as divinylbenzene, butadiene and / or butanediol diacrylate. The branching agent is generally used in amounts of from 0.0005 to 0.5 mol%, based on styrene.

Preference is given to using styrene polymers or styrene copolymers having a molecular weight in the range from 70,000 to 400,000 g / mol, particularly preferably from 190,000 to 400,000 g / mol, very particularly preferably from 210,000 to 400,000 g / mol.

Mixtures of different styrene (co) polymers can also be used. Highly suitable styrene polymers or styrene copolymers are glass clear polystyrene (GPPS), impact polystyrene (HIPS), anionically polymerized polystyrene or impact polystyrene (A-IPS), styrene-α-methylstyrene copolymers, acrylonitrile-butadiene-styrene polymers (ABS), styrene-acrylonitrile (SAN ), Acrylonitrile-styrene-acrylic esters (ASA), methyl acrylate-butadiene-styrene (MBS), methyl methacrylate-acrylonitrile-butadiene-styrene (MABS) polymers or mixtures thereof or with polyphenylene ether (PPE).

Particular preference is given to using a styrene homopolymer having a molecular weight in the range from 70,000 to 400,000 g / mol, particularly preferably 190,000 to 400,000 g / mol, very particularly preferably 210,000 to 400,000 g / mol. For the production of expanded polystyrene as component B) and / or expanded styrene copolymer as component B), in general the expandable styrene homopolymers or expandable styrene copolymers are expanded by heating to temperatures above their softening point, for example with hot air or preferably steam. as described for example in Kunststoff Handbuch 1996, Volume 4 "Polystyrene", Hanser 1996, pages 640 to 673 or US 5,112,875.

The expansion can be carried out in one or more stages. As a rule, in the one-stage process, the expandable styrene homopolymer or expandable styrene copolymer is readily expanded to the desired final size.

As a rule, in the multistage process, the expandable styrene homopolymer or expandable styrene copolymer is first expanded to an intermediate size and then expanded in one or more further stages over a corresponding number of intermediate sizes to the desired final size.

Preferably, the expansion is carried out in one stage. The content of blowing agent in the expanded styrene homopolymer (polystyrene) or expanded styrene copolymer, preferably expanded styrene homopolymer (polystyrene), is in the range from 0 to 3.5 wt .-%, preferably from 0 to 3 wt .-%, particularly preferably 0 to 2 , 5 wt .-%, most preferably 0 to 2 wt .-%, each based on the expanded styrene homopolymer (polystyrene) or Styrolcopo- lymerisat.

0 wt .-% means herein that no propellant can be detected by the usual detection methods. The expanded styrene homopolymer (polystyrene), or expanded styrene copolymer advantageously has a bulk density of from 10 to 100 kg / m ³ , preferably 15 to 90 kg / m ³ , particularly preferably 20 to 80 kg / m ³ , in particular 40 to 80 kg / m ³ .

The expanded polystyrene or expanded styrene copolymer is advantageously in the form of spheres or beads having an average diameter in the range of 0.25 to 10 mm, preferably in the range of 0.4 to 8.5 mm, in particular in the range of 0.4 to 7 mm inserted.

The expanded polystyrene beads or expanded styrene copolymer beads advantageously have a small surface area per volume, for example in the form of a spherical or elliptical particle. The expanded polystyrene or expanded styrene copolymer spheres are advantageously closed-cell. The open cell density according to DIN-ISO 4590 is usually less than 30%. Usually, the expandable polystyrene or expandable Styrolcopolyme- risat or the expanded polystyrene or expanded styrene copolymer has an antistatic coating.

As antistatic agents, the usual and common in the art substances can be used. Examples are N, N-bis (2-hydroxyethyl) -Ci 2 -C 18 -alkylamines, fatty acid diethanolamides, choline ester chlorides of fatty acids, C 12 -C 20 -alkyl sulfonates, ammonium salts.

Suitable ammonium salts contain, in addition to alkyl groups, 1 to 3 hydroxyl-containing organic radicals on the nitrogen.

Suitable quaternary ammonium salts are, for example, those having on the nitrogen cation 1 to 3, preferably 2, identical or different alkyl radicals having 1 to 12, preferably 1 to 10 carbon atoms, and 1 to 3, preferably 2 identical or different hydroxyalkyl or hydroxyalkylpolyoxyalkylene Radicals bound with any anion, such as chloride, bromide, acetate, methyl sulfate or p-toluenesulfonate.

The hydroxyalkyl and hydroxyalkyl-polyoxyalkylene radicals are those which are formed by oxyalkylation of a nitrogen-bonded hydrogen atom and are derived from 1 to 10 oxyalkylene radicals, in particular oxyethylene and oxypropylene radicals.

Particular preference is given to using as antistatic agent a quaternary ammonium salt or an alkali metal salt, in particular the sodium salt of a C 12 -C 20 alkanesulfonate or mixtures thereof. The antistatic agents can generally be added both as a pure substance and in the form of an aqueous solution.

The antistatic agent can be added in the process for the preparation of polystyrene or styrene copolymer analogously to the customary additives or applied after the preparation of the polystyrene particles as a coating.

The antistatic agent is advantageously used in an amount of 0.05 to 6 wt .-%, preferably 0.1 to 4 wt .-%, based on the polystyrene or styrene copolymer.

The expanded plastic particles B) are advantageously also after being pressed into a light lignocellulose material, preferably light wood material, preferably a multilayer lignocellulose material, more preferably a multilayer wood material, in a state in which its original shape is still recognizable. bar is. Optionally, there may be a melting of the expanded plastic particles, which are on the surface of the light lignocellulosic, preferably light wood-containing material or preferably the multilayer lignocellulosic material, preferably wood material, come.

The total amount of the expanded plastic particles B), based on the light lignocellulose-containing, preferably light wood-containing material, is in the range from 1 to 25 wt .-%, preferably 3 to 15 wt .-%, particularly preferably 3 to 12 wt .-%. The total amount of the expanded plastic particles B) with polystyrene and / or styrene copolymer as the sole plastic particle component, based on the light lignocellulose-containing, preferably light wood-containing material, is in the range from 1 to 25% by weight, preferably 3 to 15% by weight. -%, particularly preferably 3 to 12 wt .-%. It has proved advantageous to tune the dimensions of the above-described expanded plastic particles B), preferably expanded styrene polymer particles or expanded styrene copolymer particles, to the lignocellulose particles, preferably wood particles A) or vice versa. This tuning is expressed below by the relationship of the respective d'values (from the Rosin-Rammler-Sperling-Bennet function) of the lignocellulose particles, preferably wood particles A) and the expanded plastic particles B).

The Rossin-Rammler-Sperling-Bennet function is described, for example, in DIN 66145.

To determine the d values, sieve analyzes are first carried out to determine the particle size distribution of the expanded plastic particles B) and lignocellulose particles, preferably wood particles A) in analogy to DIN 66165, parts 1 and 2.

The values from the sieve analysis are then used in the Rosin-Rammler-Sperling-Bennet function and calculated d '.

The Rosin-Rammler-Sperling-Bennet function is:

R = 100 ^* exp (- (d / d ') ⁿ ))

With the following meanings of the parameters:

R remainder (wt.%) Remaining on the respective sieve bottom

d particle size

d 'particle size at 36.8 wt% balance

n width of particle size distribution Highly suitable lignocellulose particles, preferably wood particles A) have an d 'value according to Rosin-Rammler-Sperling-Bennet (definition and determination of the d value as described above) in the range from 0.1 to 5.0, preferably in the range of 0.3 to 3.0, and more preferably in the range of 0.5 to 2.75.

Highly suitable light lignocellulose-containing, preferably wood-containing materials or multilayered lignocellulose materials, preferably multilayer wood-based materials, are obtained if, for the d'values according to Rosin-Rammler-Sperling-Bennet, the lignocellulose particles, preferably wood particles A) and the particles of the expanded plastic particles B) the following relationship applies:

d 'of the particles A) <2.5 xd' of the particles B), preferably d 'of the particles A) <2.0 * d' of the particles B), particularly preferably d 'of the particles A) <1.5 * d 'of the particle B), most preferably d' of the particle A) <d 'of the particle B). The binder C) is selected from the group consisting of aminoplast resin, phenol-formaldehyde resin and organic isocyanate having at least two isocyanate groups. These components in the present applications relate to the absolute and percentage amounts with respect to the component C). As a rule, the binder C) contains the substances known to the person skilled in the art for aminoplasts or phenolformaldehyde resins and commonly referred to as hardeners, such as ammonium sulfate or ammonium nitrate or inorganic or organic acids, for example sulfuric acid, formic acid or acid regenerating substances, such as aluminum chloride, aluminum sulfate , in each case in the usual, small amounts, for example in the range of 0.1 wt .-% to 3 wt .-%, based on the total amount of aminoplast resin in the binder C).

Phenol-formaldehyde resins (also called PF resins) are known to the person skilled in the art, see, for example, Kunststoff-Handbuch, 2nd edition, Hanser 1988, Volume 10 "Duroplastics", pages 12 to 40.

As aminoplast resin here polycondensation of compounds with at least one, optionally partially substituted with organic radicals, carbamide group (the carbamide group is also called carboxamide) and an aldehyde, preferably formaldehyde, understood. As a suitable aminoplast resin, all of the specialist, preferably known for the production of wood materials, aminoplast resins can be used. Such resins and their preparation, for example, in Ullmann's Encyclopedia of Industrial Chemistry, 4th, revised and expanded edition, Verlag Chemie, 1973, pages 403 to 424 "aminoplasts" and Ullmann's Encyclopedia of Industrial

Chemistry, Vol. A2, VCH Verlagsgesellschaft, 1985, pages 115 to 141 "Amino Resins" and in M. Dunky, P. Niemz, wood materials and glues, Springer 2002, pages 251 to 259 (UF resins) and pages 303 to 313 (MUF and UF with a small amount of melamine) described.

Preferred aminoplast resins are polycondensation products of compounds having at least one carbamide group and formaldehyde, which are also partially substituted by organic radicals.

Particularly preferred aminoplast resins are urea-formaldehyde resins (UF resins), melamine-formaldehyde resins (MF resins) or melamine-containing urea-formaldehyde resins (MUF resins).

Especially preferred amino resins are urea-formaldehyde resins, for example Kaurit ^® glue types from BASF SE.

Furthermore, very preferred aminoplast resins are polycondensation products of compounds having at least one, also partially substituted with organic radicals, amino group and aldehyde, wherein the molar ratio of aldehyde: optionally partially substituted with organic radicals amino group in the range of 0.3 to 1, 0 preferred 0.3 to 0.60, more preferably 0.3 to 0.45, most preferably 0.30 to 0.40.

Furthermore, very preferred amino resins are polycondensation products of compounds having at least one amino group -NH 2 and formaldehyde, wherein the molar ratio of formaldehyde: -NH 2 group in the range of 0.3 to 1, preferably 0.3 to 0.60, especially preferably 0.3 to 0.45, very particularly preferably 0.30 to 0.40.

Furthermore, very preferred aminoplast resins are urea-formaldehyde resins (UF resins), melamine-formaldehyde resins (MF resins) or melamine-containing urea-formaldehyde resins (MUF resins), in which the molar ratio of formaldehyde: -IMH2-

Group in the range of 0.3 to 1, 0, preferably 0.3 to 0.60, particularly preferably 0.3 to 0.45, most preferably 0.30 to 0.40.

Furthermore, very preferred aminoplast resins are urea-formaldehyde resins (UF resins), wherein the molar ratio of formaldehyde: -NH2 group in the range of 0.3 to 1, preferably 0.3 to 0.60, particularly preferably 0.3 to 0.45, most preferably 0.30 to 0.40. The said aminoplast resins are usually used in liquid form, usually suspended in a liquid suspending agent, preferably in aqueous suspension, but may also be used as a solid.

The solids content of the aminoplast resin suspensions, preferably aqueous suspension, is usually from 25 to 90% by weight, preferably from 50 to

70% by weight. The solids content of the aminoplast resin in aqueous suspension can be determined according to Günter Zeppenfeld, Dirk Grunwald, adhesives in the wood and furniture industry, 2nd edition, DRW-Verlag, page 268. To determine the solids content of aminoplast glues, 1 g of aminoplast glue is accurately weighed into a weighing dish, finely distributed on the bottom and dried for 2 hours at 120 ^° C. in a drying oven. After tempering to room temperature in a desiccator, the residue is weighed and calculated as a percentage of the initial weight.

The aminoplast resins are prepared by known processes (see LJII-man literature "Aminoplasts" and "Amino Resins" cited above, and Dunky et al. Cited above) by reacting the compounds containing carbamide groups, preferably urea and / or melamine, with Aldehydes, preferably formaldehyde, in the desired molar ratios of carbamide group: aldehyde, preferably in water as solvent. The setting of the desired molar ratio of aldehyde, preferably formaldehyde: optionally partially substituted with organic radicals amino group can also happen by addition of -NH2 group-carrying monomers to formally dehydreicheren finished, preferably commercial, aminoplast resins. NH 2 group-carrying monomers are preferably urea, melamine, more preferably urea.

Another component of the binder C) may be an organic isocyanate having at least two isocyanate groups. As a suitable organic isocyanate all known to those skilled in the art, preferably the known for the production of wood materials or polyurethanes, organic isocyanates can be used. Such organic isocyanates and their preparation and use are described, for example, in Becker / Braun, Kunststoff Handbuch, 3rd revised edition, Volume 7 "Polyurethane", Hanser 1993, pages 17 to 21, pages 76 to 88 and pages 665 to 671. Preferred organic isocyanates are oligomeric isocyanates having 2 to 10, preferably 2 to 8 monomer units and an average of at least one isocyanate group per monomer unit. A particularly preferred organic isocyanate is the oligomeric organic isocyanate PMDI ("polymeric methylenediphenylene diisocyanate") obtainable by condensation of formaldehyde with aniline and phosgenation of the isomers and oligomers formed in the condensation (see, for example, Becker / Braun, Kunststoff Handbuch, 3 revised edition, volume 7 "Polyurethane", Hanser 1993, pages 18 last paragraph to page 19, second paragraph and page 76, fifth paragraph).

For the purposes of the present invention very suitable PMDI products are the products of LUPRANAT ^® type series of BASF SE, in particular LUPRANAT ^® M 20 FB of BASF SE.

It is also possible to use mixtures of the described organic isocyanates, the mixing ratio not being critical according to current knowledge. The resin components of the binder C) can be used alone, for example, aminoplast resin as the sole resin component of the binder C) or organic isocyanate as the sole resin component of the binder C) or PF resin as the sole component of the binder C). However, the resin components of the binder C) can also be used as a combination of two or more resin components of the binder C).

The total amount of the binder C), based on the light wood-containing material, is in the range from 3 to 50 wt .-%, preferably 5 to 15 wt .-%, particularly preferably 7 to 10 wt .-%.

In this case, generally the total amount of the aminoplast resin (always based on the solid), preferably of the urea-formaldehyde resin and / or melamine-urea-formaldehyde resin and / or melamine-formaldehyde resin, particularly preferably urea-formaldehyde resin, in the binder C), based on the light lignocellulosic, preferably light wood-containing material in the range of 1 to 45 wt .-%, preferably 4 to 14 wt .-%, particularly preferably 6 to 9 wt .-%.

In this case, in general, the total amount of the organic isocyanate, preferably of the oligomeric isocyanate having 2 to 10, preferably 2 to 8 monomer units and an average of at least one isocyanate group per monomer unit, particularly preferably PMDI, in the binder C), based on the light lignocellulose-containing in front- preferably light wood-containing substance in the range of 0 to 5 wt .-%, preferably 0.1 to 3.5 wt .-%, particularly preferably 0.5 to 1, 5 wt .-%.

The proportions of the amino resin to the organic isocyanate resulting from the above-described ratios of the binder aminoplast resin to light lignocellulose-containing, preferably light wood-containing, substance or the binder organic isocyanate to light lignocellulose-containing, preferably light wood-containing material. Preferred embodiments of a light wood-containing material contain 55 to 92.5 wt .-%, preferably 60 to 90 wt .-%, in particular 70 to 88 wt .-%, based on the light wood-containing material, wood particles, wherein the wood particles have an average density from 0.4 to 0.85 g / cm ³ , preferably 0.4 to 0.75 g / cm ³ , in particular 0.4 to 0.6 g / cm ³ , 3 to 25 wt .-%, preferably 3 to 15 wt .-%, in particular 3 to 10 wt .-% based on the light wood-containing material, expanded polystyrene and / or expanded styrene copolymer as component B), with a bulk density of 10 to 100 kg / m ³ , preferably 20 to 80 kg / m ³ , in particular 30 to 60 kg / m ³ , and 3 to 40 wt .-%, preferably 5 to 25 wt .-%, in particular 5 to 15 wt .-%, based on the light wood-containing material, binder C ), the total amount of the amino resin, preferably the urea-formaldehyde resin and / or melamine-urea-formaldehyde resin and / or melamine-formaldehyde resin, being particularly preferred gt urea-formaldehyde resin, in the binder C), based on the light wood-containing material in the range of 1 to 45 wt .-%, preferably 4 to 14 wt .-%, particularly preferably 6 to 9 wt .-% and wherein the middle Density of the light wood-containing material in the range of 200 to 600 kg / m ³ , preferably in the range of 300 to 575 kg / m ³ , is located.

Optionally, in the light lignocellulose-containing, preferably light wood-containing material or multilayered lignocellulose material according to the invention, preferably multilayer wood material, further commercial additives known to the person skilled in the art may be present as component D), for example water repellents, such as paraffin emulsions, fungicides, formaldehyde scavengers Example urea or polyamines, and flame retardants. The present invention further relates to a method for producing a multilayered lignocellulosic material, preferably wood material, containing at least three lignocellulosic material layers, preferably wood material layers, wherein at least the middle layer (s) a light lignocellulosic, preferably light wood-containing material having an average density in the Range from 200 to 600 kg / m ³ and with further features as described above and in the claims, containing and wherein the components for the individual layers uhe superimposed and pressed under elevated temperature and elevated pressure, and wherein the expanded plastic particles B) of expandable plastic particles with a content of blowing agent in the range of 0.01 to 4 wt .-%, based on the expandable plastic particles, are obtained. Preferred parameter ranges and preferred embodiments with regard to the average density of the light lignocellulose-containing material, preferably light wood-containing material and with regard to the components A), B), C) and D) and the combination of the features correspond to those described above. The processes for producing multilayered lignocellulosic materials, preferably wood-based materials, are known in principle and described, for example, in M. Dunky, P. Niemz, Holzwerkstoffe und Glue, Springer 2002, pages 91 to 150.

As an example of a method for producing a multilayered lignocellulose material according to the invention, the preparation of a multilayer wood-based material according to the invention is described below.

After cutting the wood, the chips are dried. Thereafter, if necessary, coarse and fines are removed. The remaining chips are sorted by sieving or sifting in the air stream. The coarser material is used for the middle layer, the coarser material for the cover layers.

Middle layer and outer layer chips are mixed separately with the components B) (only the middle layer (s)), C) (middle layer) and optionally D) (middle layer and / or outer layers) and with an aminoplast resin (top layer), blended ,,) and then scattered.

First, the cover layer material is scattered on the forming belt, then the middle layer material - containing the components B), C) and optionally D) - and finally again cover layer material. The three-layer chip cake thus produced is precompressed cold (usually at room temperature) and then pressed hot.

The pressing can be carried out by all methods known to the person skilled in the art. Usually, the wood particle cake is pressed at a press temperature of 150 ⁰ C to 230 ⁰ C to the desired thickness. The pressing time is normally 3 to 15 seconds per mm plate thickness. This gives a three-layer chipboard.

The average density of the multilayered, preferably of the inventive three-layer, lignocellulose material, preferably wood material, according to the invention is in the range from 300 kg / m ³ to 600 kg / m ³ , preferably in the range from 350 kg / m ³ to 600 kg / m ³ , more preferably in the range of 400 kg / m ³ to 500 kg / m ³ .

Middle layers in the sense of the invention are all layers that are not the outer layers.

The outer layers (usually referred to as "cover layer (s)") preferably contain no component B. Preferably, the multilayered lignocellulose material according to the invention, preferably multilayer wooden material, contains three lignocellulosic layers, preferably mechanical pulp layers, wherein the outer cover layers together contain 1 to 25% of the total Thickness of the multilayered lignocellulose material according to the invention, preferably make wood material, preferably 3 to 20%, in particular 5 to 15%.

The binder used for the outer layers is usually an aminoplast resin, for example urea-formaldehyde resin (UF), melamine-formaldehyde resin (MF), melamine-urea-formaldehyde resin (MUF) or the binder C according to the invention. Preferably, the binder used for the outer layers is an aminoplast resin, more preferably a urea-formaldehyde resin, most preferably an aminoplast resin wherein the molar formaldehyde: -NH 2 group ratio is in the range of 0.3 to 1.0.

The thickness of the multilayered lignocellulosic material according to the invention, preferably wood-based material, varies with the field of application and is generally in the range of 0.5 to 100 mm; preferably in the range of 10 to 40 mm, in particular 15 to 20 mm.

Furthermore, the present invention relates to the use of the inventive light lignocellulose-containing, preferably light wood-containing material and the multilayer lignocellulosic material according to the invention, preferably multilayer wood material for the production of objects of all kinds, for example furniture, furniture parts or packaging materials, the use of the light lignocellulosic material according to the invention, preferably light wood-containing material and the multilayer lignocellulose material according to the invention, preferably multilayer wood material in the construction sector. Examples of items of all kinds include furniture, furniture parts and packaging materials, wall and ceiling panels, doors and floors. Examples of furniture or furniture parts are kitchen furniture, cabinets, chairs, tables, countertops, for example for kitchen furniture, desk tops. Examples of packaging materials are boxes, boxes.

Examples of the construction sector are building construction, civil engineering, interior construction, tunneling, where the lignocellulose-containing materials according to the invention, preferably light wood-containing materials or multilayer lignocellulosic materials according to the invention, preferably wood-based materials can be used as shuttering panels or as a carrier.

The advantages of the present invention are the low density of the light lignocellulose-containing material according to the invention, preferably light wood-containing material or multilayer lignocellulose material according to the invention, preferably multilayer wood material, while maintaining good mechanical stability. Furthermore, the light lignocellulose-containing material according to the invention, preferably light wood-containing material and multilayer lignocellulose material according to the invention, preferably multilayer wood material can be easily produced; there is no need to convert the existing plants of the wood-based material industry for the production of the multilayer lignocellulose materials according to the invention, preferably multilayer wood-based materials. Surprisingly good is the Bekantbarkeit the light wood-containing materials according to the invention or especially of the multilayer wood materials. The edge adheres particularly well and is not uneven or wavy, the narrow surface, in particular of the multilayer wood material, is not characterized by the edge through, the edge is pressure-stable and edging can be done with the usual machines of plate making and edging.

Surprisingly, even formaldehyde-poor glues, ie usually glues with a small molar formaldehyde: -NH2 group ratio in the range of 0.3 to 1, 0, preferably 0.3 to 0.6, lead to light lignocellulose-containing, preferably light wood-containing materials or multilayer lignocellulosic materials , preferably wood-based materials, the mechanical properties, for example the transverse tensile strength, of such light lignocellulose-containing substances, preferably light wood-containing substances or multilayer lignocellulose materials, preferably multilayer wood-based materials, being unexpectedly high.

The swelling values of the multilayered lignocellulose materials according to the invention, preferably multilayer wood-based materials, are smaller than the swelling values of an analogous plate of the same density without component B). An advantage of the invention is that the expanded plastic particles recovered from the low blowing agent expandable (compact) plastic particles, if any, need not be stored for long periods of time. sen to reduce the content of combustible blowing agent prior to further processing of the expanded plastic particles to lignocellulosic material, such as chipboard. Examples

A) Preparation of the expanded polystyrene with low pentane content

In an extruder, 95 parts by weight of polystyrene 158 K (BASF SE),

0.2 parts by weight of Luwax AH3 (BASF SE) together with 3.5 parts by weight of pentane (a commercially available pentane isomer mixture of n-pentane and iso-pentane). The resulting polymer melt was conveyed through a die plate and granulated to expandable particles by means of pressurized underwater granulation.

The expandable particles were treated with water vapor in a continuous conventional prefoamer. By varying the evaporation pressure and the steaming time, a bulk density of 50 kg / m ^{3 of} the expanded polystyrene particles was set

The expanded polystyrene thus obtained had a pentane content of 2.5% by weight and, after less than one hour, was used directly for the preparation of a light wood-containing substance. A-V) Comparison: Preparation of the expanded polystyrene with commercial

pentane content

As described in A) above, an expandable polystyrene was prepared, but 6.5 parts by weight of pentane were used.

This product was treated as described in A) in a prefoamer and adjusted to a bulk density of 50 kg / m ³ . The pentane content of this expanded polystyrene was 5% by weight.

B) Production of a multilayer wood material with and without component B) using urea-formaldehyde glues

B1) Leimflotten for the corresponding layers

As glue was Kaurit ^® glue KL 347 of BASF SE, a UF resin. The glue was mixed with other components (see the following table) to a glue liquor. The composition of the glue fleets for the top and middle layers are shown in the following table. Table 1: Leimflotten for cover and middle layer

B2) Production of the three-layer wood materials according to the invention

The gluing and pressing of the wood shavings are analogous to conventional processes for the production of chipboard. B2.1) gluing of the middle layer material

In a mixer, coarse spruce chips, expanded polystyrene (prepared according to A) above) were mixed with the middle layer sizing liquor (Table 1 above) so that the amount of sizing (as a solid) was 8.5% by weight, based on at The amount of expanded polystyrene, based on the total amount of dry wood plus expanded polystyrene, was 10% by weight.

B2.2) Gluing of the Top Layer Material In a mixer, fine spruce chips were mixed with the size coat for the top layer (according to Table 1 above), so that the amount of glue (as a solid) was 8.5% by weight, based on bare wood.

B3) comparative experiments

B3.1) gluing of the middle layer material (expanded polystyrene aus

expandable polystyrene higher pentane content)

In a mixer, coarse spruce chips, expanded polystyrene (prepared according to AV) above) were mixed with the middle layer sizing liquor (according to Table 1 above) so that the amount of sizing (as a solid) was 8.5% by weight, based on at The amount of expanded polystyrene, based on the total amount of dry wood plus expanded polystyrene, was 10% by weight. B3.2) Gluing of the cover layer material As described in B2.2 above.

B 4) Pressing the glued chips

B4.1) Experiments of the Invention

The material for the production of a three-layer chipboard was spread in a 30 x 30 cm mold. In this case, first the cover layer material, then the middle layer material and finally the cover layer material were scattered. The total mass was chosen so that at the end of the pressing process, the desired density results in a desired thickness of 16 mm. The Weight Ratio (Weight Ratio) Cover Layer Material: Middle Layer Material: Topcoat material was 17: 66: 17 in all runs.

The cover layer material used was the mixture described above under B2.2). The middle layer material used was the mixture described above under B2.1). After spreading (press temperature 210 ⁰ C, pressing time 210 s) at room temperature, thus "cold", pre-compacted and then pressed in a hot press. The target thickness of the plate was in each case 16 mm.

B4.2) Comparative experiments

B4.2.1) (With expanded polystyrene higher pentane content)

Procedure analogous to B4.1, but with the middle layer material from B3.1) and the cover layer material from B3.2).

B4.2.2) (without expanded polystyrene)

B4.2.2.1) Gluing of the Middle Layer Material (Without Expanded Polystyrene) In a mixer, coarse spruce chips were mixed with the middle layer sizing liquor (Table 1 above) so that the amount of sizing (as a solid) was 8.5% by weight. related to atro wood was.

B4.2.2.2) Gluing of the cover layer material In a mixer, fine spruce chips were mixed with the size coat sizing liquor (shown in Table 1, above) so that the amount of sizing (as a solid) was 8.5% by weight, based on dry wood. Analog B4.1 pressed a three-layer plate.

C) Examination of the multilayer wood-based materials

C 1) density

The density was determined 24 hours after preparation according to EN 1058.

C 2) Transverse tensile strength The transverse tensile strength is determined according to EN 319.

The results of the tests are summarized in Table 2.

Table 2

It can be seen that the wood material B.4.1 according to the invention, obtained with expanded polystyrene of low pentane content, within the measuring accuracy, has the same transverse tensile strength as that with expanded polystyrene with high pentane content (B4.2.1), but significantly better values than a wood material without expanded polystyrene (B4.2.2), comparable density. The advantage of the invention is, inter alia, that the emissions of propellant, for example pentane, in the manufacture and processing of expanded plastic particles, such as expanded polystyrene particles, are significantly reduced, which, in addition to the positive effects on the atmosphere, a advantageous influence on the safe handling of the expanded plastic particles, such as expanded polystyrene particles, has, the product properties of the wood material continue to be good.

Claims

claims

1. A process for producing a light lignocellulosic material having a mean density in the range of 200 to 600 kg / m ³ , in which, in each case based on the lignocellulosic substance:

A) 30 to 95% by weight of lignocellulose particles;

C) 3 to 50 wt .-% of a binder selected from the group consisting of aminoplast resin, phenol formaldehyde resin and organic isocyanate anat with at least two isocyanate groups and optionally D) additives and then pressed under elevated temperature and under elevated pressure, characterized in that the expanded plastic particles are obtained from expandable plastic particles with a blowing agent content in the range from 0.01 to 4% by weight, based on the expandable plastic particles.

2. The method according to claim 1, wherein the component B) is selected from the group consisting of styrene homopolymer and styrene copolymer.

3. Process according to claims 1 and 2, wherein the blowing agent is selected from the group consisting of aliphatic C3- to Cio-hydrocarbons.

4. The method according to claims 1 to 3, wherein the component C) contains an aminoplast resin.

5. Use of expandable plastic particles with a blowing agent content in the range from 0.01 to 4% by weight for the production of component B) of a light lignocellulose-containing material having an average density in the range from 200 to 600 kg / m ³ , comprising in each case based on the lignocellulose-containing substance:

A) 30 to 95% by weight of lignocellulose particles;

D) additives.

6. Use according to claim 5, wherein component B) is selected from the group consisting of styrene homopolymer and styrene copolymer.

7. Use according to claims 5 and 6, wherein the blowing agent is selected from the group consisting of C3 to C10 aliphatic

Hydrocarbons.

8. Use according to claims 5 to 7, wherein the component C) contains an aminoplast resin.

9. A process for producing a multi-layered lignocellulosic material containing at least three layers, wherein only the middle layer or at least a portion of the middle layers contains a light lignocellulose-containing substance as defined in claims 1 to 4, wherein the components for the individual layers are stacked and compressed under elevated temperature and elevated pressure and wherein the expanded plastic particles B) of expandable plastic particles with a content of blowing agent in the range of 0.01 to 4 wt .-%, based on the expandable plastic particles, are obtained.

10. The method according to claim 9, wherein the outer cover layers contain no component B).

1 1. Use of the light lignocellulose-containing substances, defined in the claims 1 to 4 or the multilayer lignocellulosic material, defined in the

Claims 9 to 10 for the production of objects of all kinds and in the construction sector.

12. Use of the light lignocellulose-containing substance, defined in claims 1 to 4 or the multilayered lignocellulose material, defined in the

Claims 9 to 10 for the production of furniture and furniture parts, packaging materials, in the home or interior.