Method for manufacturing an osb wood panel

Abstract

The present invention relates to a method for manufacturing an OSB wood panel, said method comprising the following steps: providing wood strands; gluing the wood strands with a binder system comprising a component A comprising at least one sugar, at least one sugar alcohol or a mixture thereof, and at least one compound of the general formula (I) Ra 1SiX(4-a), where X is alkoxy, R1 is an organic residue selected from a group comprising C1-C10 alkyls which may be interrupted by -O- or -NH-, where R1 includes at least one functional group Q1 which is selected from a group comprising a methacrylic, methacryloxy, vinyl, alkoxy, amino, isocyano and epoxy group, and a = 0, 1, 2, 3, in particular 0, 1 or 2, and a component B consisting of at least one isocyanate, component A and component B being applied separately to the wood strands; scattering the glued wood strands onto a conveyor belt; and pressing the glued wood strands to form an OSB wood panel, and the method being carried out in a production plant with an increase in the plant speed of at least 10%, preferably at least 15%, particularly preferably at least 20%, even more preferably at least 25% when compared to the initial speed of the production plant.

Description

[0001] Process for producing an OSB wood-based panel

[0002] The present invention relates to a method for producing an OSB wood-based panel.

[0003] Description

[0004] Oriented strand boards (OSB) are wood-based panels made from long strands of wood. Originally a waste product of the veneer and plywood industries, OSB is increasingly being used in timber and prefabricated house construction because it is lightweight yet meets the structural requirements of building boards. OSB is used as building boards, as wall and roof paneling, and even in flooring.

[0005] OSB is manufactured in a multi-stage process. First, the chips or strands of debarked roundwood, preferably softwood, are peeled lengthwise by rotating knives. During the subsequent drying process, the natural moisture content of the strands is reduced at high temperatures. The moisture content of the strands can vary depending on the adhesive used, but it should be well below 10% to avoid splitting during later pressing. Depending on the adhesive, wetting on moister strands or on dry strands can be more beneficial. Furthermore, as little moisture as possible should be present in the strands during the pressing process in order to minimize the steam pressure that develops during the pressing process, as this could otherwise cause the raw board to burst.

[0006] After the strands have dried, they are fed into a gluing device, where the glue or adhesive is finely distributed onto the chips. PMDI (polymeric diphenylmethane diisocyanate) or MUPF (melamine urea phenol formaldehyde) glues are predominantly used for gluing. These glues can also be mixed in OSB. These glues are used because, as mentioned above, OSB is often used for structural applications. In these applications, moisture-resistant glues are required.

[0007] After gluing, the glued strands are spread in spreading devices alternately lengthwise and crosswise to the production direction, so that the strands are arranged crosswise in at least three layers (lower cover layer - middle layer - upper cover layer). The spreading direction of the lower and upper cover layers is the same, but differs from the spreading direction of the middle layer. The strands used in the cover layer and middle layer also differ from one another. For example, the strands used in the cover layers are flat, while those used in the middle layer are less flat and even chip-shaped. Typically, two material strands are used in the production of OSB: one with flat strands for the later cover layers and one with "chips" for the middle layer. Accordingly, the strands in the middle layer can be of lower quality, since the flexural strength is essentially generated by the cover layers.Therefore, fines produced during machining can also be used in the middle layer of OSB boards.

[0008] Following the scattering of the strands, they are continuously pressed under high pressure and high temperature of e.g. 200 to 250°C.

[0009] In the production of wood-based materials (HWS), such as the OSB described above, a significant portion of the product costs is caused by depreciation for the extremely expensive production equipment. The continuous presses, which are commonly used today, contribute significantly to the total product cost. The limiting factor for wood-based materials is always the curing of the glues used. These are always hardened by thermal activation. However, since wood is a thermal insulator, heat transfer from the press to the chip or fiber cake plays an important role.

[0010] It is known that adding hardeners can accelerate the curing of glues and thus increase plant output. This is a proven method for urea-formaldehyde glues, which are used in large quantities, because the hardeners have little or no tendency to cure the glue at room temperature. This means that little to no pre-curing occurs during short plant downtimes.

[0011] The situation is different with PMDI glue. This glue, which is used primarily in the production of OSB, reacts with most hardeners (e.g., amines, polyols) even at room temperature. These hardeners often have the additional problem that they must be added to the PMDI and thoroughly mixed before being applied to the strands. These hardeners are usually used as aqueous solutions, which leads to an additional reaction of the PMDI with the water to form polyurethane and to the deposition of the polyurethane. This results in disadvantages, particularly a reduced ability to influence the output and productivity of the production plant, and higher costs.

[0012] By using a chemical that is not a classic hardener but would nevertheless accelerate the curing of PMDI glue, it might be possible to significantly increase production volume.

[0013] The present invention is therefore based on the technical problem of increasing the productivity of an OSB plant. This should, if possible, avoid the need for technical modifications. Furthermore, the process should not become significantly more expensive.

[0014] This object is achieved by a method for producing OSB having the features of claim 1.

[0015] Accordingly, a process for producing an OSB wood-based panel is provided, which comprises the following steps: a) providing wood strands; b) gluing the wood strands with a binder system comprising a component A comprising i) at least one sugar, at least one sugar alcohol or a mixture thereof, and ii) at least one compound of the general formula (I)

[0016] Ra 1 SiX(4-a) where

[0017] - X is alkoxy,

[0018] - R 1an organic radical is selected from a group comprising C1 -C10 alkyl, which may be interrupted by -O- or -NH-

[0019] - where R 1 has at least one functional group Qi selected from a group containing a methacrylic, methacryloxy, vinyl, alkoxy, amino, isocyano and epoxide group, and

[0020] - a = 0, 1, 2, 3, in particular 0, 1 or 2, and a component B consisting of at least one isocyanate, wherein component A and component B are applied separately from one another to the wood strands, c) sprinkling the glued wood strands onto a conveyor belt; and d) pressing the glued wood strands to form an OSB wood-based panel, and wherein the process is carried out in a production plant with an increase in the plant speed of at least 10%, preferably of at least 15%, particularly preferably of at least 20%, even more preferably of at least 25% compared to an initial speed of the production plant.

[0021] In the context of the present invention, an increase in the system speed is understood to mean an acceleration of the system speed compared to an initial speed of the production system. Production systems for OSB production are typically operated at a speed of up to 340 mm / sec. As can be seen from the exemplary embodiments listed below, the present method now allows an increase in the process or feed speed to more than 340 mm / sec, preferably more than 380 mm / sec, particularly preferably > 400 mm / sec. The feed speed can thus be 400-460 mm / sec, preferably 400-435 mm / sec. It should be noted that the absolute feed speed depends on the length of the production system and the thickness of the OSB to be produced; i.e. the absolute feed speed can vary from production system to production system.

[0022] The use of sugar-containing binder compositions in wood-based panels is known. EP 3 067 402 A1 describes a binder composition for wood-based panels that can be produced from a sugar (e.g., sorbitol), a modified silane (tetraethoxysilane, glycidyloxypropyltriethoxysilane), and an isocyanate (PMDI). The binder composition is sprayed onto wood strands as a mixture of these substances, and the wood strands coated with the binder composition are then pressed into OSB. The use of a mixture of the three substances prevents absorption or diffusion of the PMDI glue into the wood fibers, thereby making it possible to reduce the amount of binder required in the production process for wood-based panels. This effect results from the fact that the compounds formed from the silane compound and polyalcohol react with the polymer adhesive, such as, for example,PMDI glue, or can react with the OH groups of the wood. The macromolecules formed by condensation with the glue are now no longer able to pass through the hydrophobic fatty acid layer of the strands due to the hydrophilic residues. As a result, the existing binder composition remains on the surface of the strands or fibers and does not diffuse into the wood matrix. One could also say that the polymer adhesive is now equipped with a hydrophilic anchor. According to EP 3 067 402 A1, the use of a mixture of the three components sugar, silane, and isocyanate before applying the binder to the wood strands is therefore essential in order to achieve a reduction in the amount of binder used.

[0023] EP 3 995 538A1 describes a sugar-based binder system for wood-based panels, consisting of three components: a sugar, polyvinyl alcohols, and isocyanate. The three components are applied separately and sequentially to the wood particles used for the wood-based panels, and the coated wood particles are then pressed into wood-based panels.

[0024] The key difference between this process and the processes described in the prior art is the separate application of components A (sugar and silane) and B (isocyanate). According to the invention, a two-component system comprising component A consisting of sugar / sugar alcohol and at least one silane, and component B consisting of an isocyanate, is added separately to the strands during gluing in a mixer (e.g., trough mixer) or in a gluing drum (coil). Thus, there is no mixing of the components of the binder system prior to application to the wood strands, preventing any undesired reaction, e.g., of the isocyanate with water from an aqueous solution of component A. The risk of pre-curing of the binder is thus reduced.

[0025] Furthermore, it has been shown that the use of the inventive two-component system consisting of a sugar-silane reaction product and isocyanate surprisingly results in an acceleration of the production rate. This effect is not easily explained.

[0026] As already mentioned above and can be seen from the exemplary embodiments listed below, the present method now allows an increase in the process or feed rate to more than 340 mm / s, preferably more than 380 mm / s, particularly preferably > 400 mm / s. Thus, the feed rate can be 400-460 mm / s, preferably 400-435 mm / s.

[0027] Using the process according to the invention, more OSB can be produced. Typically, an increase in the quantity of OSB produced is achieved by increasing the amount of glue. Increased glue application is necessary to compensate for the reduced strength resulting from uncured glue. It is therefore all the more surprising that the demonstrated increased performance is accompanied by a reduction in the amount of glue. The increased quantity of OSB produced also results in a cost advantage in terms of the specific costs of the production plant per cubic meter of OSB produced.

[0028] As mentioned, the inventive process also reduces the amount of glue, which leads to further cost savings. With a reduction of approximately 10%, at current PMDI adhesive costs, an amount of several thousand euros can be achieved for a production yield of up to 2,000 cubic meters per day. This also enables an improvement in the ecological footprint of the OSB produced through reduced use of fossil raw materials used to produce PMDI. A saving of 10% corresponds to approximately 2 kg per cubic meter of OSB. At 1,500 cubic meters of OSB per day, this adds up to 3,000 kg per day. At 2,000 euros per ton for PMDI, this already results in savings of approximately 6,000 euros per day.

[0029] The silane used in component A is actually a primer designed to improve the adhesion of the isocyanate to the strands. The surprising fact that this primer also allows for an acceleration of production speed is not readily explained, as the silane class of substances is not known for this property. The two-component binder system is applied either before, with, or after the isocyanate application.

[0030] The separate application of the components of the binder system also allows for quick changes in the proportions of the components. A further advantage is that environmentally harmful ingredients such as heavy metals and halogens can be omitted from the binder system.

[0031] In one embodiment, the present method comprises the following steps: a) producing wood strands (OSB strands) from suitable wood, b) if necessary, intermediate storage of the wood strands, in particular in silos or bunkers, c) drying the wood strands, d) sorting or sifting the wood strands according to the size of the wood strands, e) gluing the wood strands with the above-mentioned binder system comprising a component A and a component B, f) applying the glued wood strands to a conveyor belt by means of wind and / or throw sifting, and g) pressing the glued wood strands arranged on the conveyor belt.

[0032] In addition to the process steps listed above, the wood chips are cleaned of foreign matter before they are shredded, e.g. by dry cleaning or wet cleaning.

[0033] Sugar of component A

[0034] In one embodiment of component A of the present binder system, reducing mono- and / or disaccharides are used. For the purposes of the present application, reducing mono- or disaccharides are understood to be saccharides that have at least one aldehyde group in the linear state. Non-reducing saccharides, on the other hand, have no free aldehyde groups. An example of a non-reducing disaccharide is sucrose, in which the two monosaccharides glucose and fructose are linked to one another in acetal form via an α,β-1,2-glycosidic bond under neutral and basic conditions. However, cleavage of sucrose into the reducing monosaccharides glucose and fructose is possible under acidic conditions.

[0035] In a preferred embodiment, pentoses and hexoses are used as monosaccharides. Pentoses and hexoses are particularly selected from the group consisting of arabinose, ribose, xylose, glucose (dextrose), mannose, galactose, and fructose. These saccharides can be used in both their D- and L-forms.

[0036] In a further embodiment, sugar alcohols selected from a group consisting of tetrahydric, pentahydric, and hexahydric alcohols (also known as reduced sugars or alditols) are used. Threitol, erythritol, and pentaerythritol can be used as tetrahydric alcohols; arabitol, adonitol, and xylitol can be used as pentahydric alcohols; and sorbitol, mannitol, dulcitol, and dipentaerythritol can be used as hexahydric alcohols. The use of sorbitol (or sorbitol) has proven particularly advantageous.

[0037] Therefore, only sugar-based polyols are used as polyols or polyalcoholic compounds. Synthetic polyols such as glycols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, and polybutylene glycol are not used. In particular, 1,2-propylene glycol is not used as a glue component in this case.

[0038] Silane of component A

[0039] The hydrolyzable radical X of the silane of formula (I) is advantageously selected from a group containing Ci-6-alkoxy, in particular methoxy, ethoxy, n-propoxy, i-propoxy and butoxy.

[0040] The organic residue R 1The silane of the general formula (I) is preferably selected from a group comprising C1-C10 alkyl, preferably C1-C8 alkyl, which may be interrupted by -O- or -NH-. Particular preference is given to methyl, ethyl, propyl, pentyl, hexyl, heptyl, and octyl.

[0041] In one embodiment of the present composition, the at least one functional group Q 1 of the silane of the general formula (I) selected from a group containing an epoxide, in particular a glycidyl or glycidyloxy group, a methacryloxy, a vinyl, or an isocyano group. Particularly preferred functional group Q 1 is a glycidyloxy or isocyano group. The functional group Q 1 advantageously has a residue with a double bond or an epoxy group which can be activated and polymerized by means of UV radiation.

[0042] The functional groups through which crosslinking between the polymer adhesive and the wood surface is possible include, in particular, polymerizable and / or polycondensable groups, whereby the polymerization reaction also includes polyaddition reactions. The functional groups are preferably selected such that organic crosslinking between the polymer adhesive and the wood surface, and possibly also between different adhesive systems, can be achieved via optionally catalyzed polymerization and / or condensation reactions.

[0043] In a preferred embodiment, the present binder composition comprises at least two compounds of the general formula (I).

[0044] Thus, in one embodiment, a silane mixture can be used in which a first compound of the formula SiX4where X corresponds to alkoxy, in particular methoxy, ethoxy, n-propoxy or i-propoxy, and a second compound of the formula R a SiX(4- a ) with a= 1 or 2, where X is alkoxy, in particular methoxy, ethoxy, n-propoxy or i-propoxy, R is methyl, ethyl, n-propyl or n-butyl and Q is a glycidyl or glycidyloxy group, an alkoxy, an amino or an isocyano group.

[0045] In a further embodiment, a silane mixture can be used in which a first compound of the formula SiX4where X corresponds to methoxy, ethoxy, n-propoxy or i-propoxy, and a second compound of the formula R a SiX( 4.a ) with a= 1, where X is methoxy, ethoxy, n-propoxy or i-propoxy, R is methyl, ethyl, n-propyl or n-butyl and Q is glycidyl or glycidyloxy group.

[0046] The molar ratio of the first and second compounds can be 0.1 to 1 mol, preferably 0.1 to 0.5 mol, particularly preferably 0.1 to 0.4 mol.

[0047] In a particularly preferred embodiment, tetraethoxysilane, tetramethoxysilane, gamma-isocyanatopropyltriethoxysilane, glycidyloxypropyltriethoxysilane and glycidyoxypropyltrimethyoxysilane are used as silanes.

[0048] According to one variant, component A comprises a silane mixture in which a first compound of the formula SiX4where X corresponds to alkoxy, in particular methoxy, ethoxy, n-propoxy or i-propoxy, and a second compound of the formula R a SiX( 4.a) with a= 1 or 2, where X is alkoxy, in particular methoxy, ethoxy, n-propoxy or i-propoxy, R is methyl, ethyl, n-propyl or n-butyl and Q is a glycidyl or glycidyloxy group, an alkoxy, an amino or an isocyano group, and tetrahydric alcohols such as threitol, erythritol, pentaerythritol, pentahydric alcohols such as arabitol, adonitol, xylitol and hexahydric alcohols such as sorbitol, mannitol, dulcitol, dipentaerythritol. According to a preferred variant, component A comprises a silane mixture in which a first compound of the formula SiX4 with X corresponds to methoxy, ethoxy, n-propoxy or i-propoxy, and a second compound of the formula R a SiX(4- a ) with a= 1, where X is methoxy, ethoxy, n-propoxy or i-propoxy, R is methyl, ethyl, n-propyl or n-butyl and Q is glycidyl or glycidyloxy group, and hexahydric alcohols such as sorbitol, mannitol, dulcitol, dipentaerythritol.

[0049] According to a particularly preferred variant, component A comprises tetraethoxysilane, glycidyloxypropyltriethoxysilane, and sorbitol.

[0050] In a further embodiment, it is possible to add nanoparticles to the component A composition. The particles preferably used have a size between 2 and 400 nm, preferably between 2 and 100 nm, particularly preferably between 2 and 50 nm. The particles can in particular be of oxidic, hydroxidic or oxyhydroxidic nature, which can be produced via different processes such as ion exchange processes, plasma processes, sol-gel processes, grinding or flame deposition. In a preferred embodiment, particles based on SiO2, Al2O3, ZrO2, TiO2, SnO are used, with particular preference being given to nanoscale SiO2 particles in the form of an aqueous suspension (e.g. acidic suspension of SiO2 stabilized with Al 3+ - or Na +-cations) can be used.

[0051] In one variant, the at least one component A comprising silane and sugar / sugar alcohol is applied to the wood strands, in particular to the wood strands, in an amount between 0.01 and 0.5 wt.%, preferably between 0.02 and 0.4 wt.%, particularly preferably between 0.04 and 0.3 wt.%, based on dry wood. Dry wood is the unit of measurement for the mass of one ton of absolutely dry wood.

[0052] The amount of component A comprising at least one silane compound of formula (I) and at least one sugar / sugar alcohol can be 0.4 to 20 wt%, preferably 0.8 to 16 wt%, particularly preferably 1.6 to 12 wt%, based on the amount of isocyanate as component B.

[0053] Preferably, the at least one component A consisting of silane and sugar / sugar alcohol is used as an aqueous solution with a concentration of 10-50 wt%, preferably 12-30 wt%, and appropriate amounts of the aqueous solution are used to achieve the appropriate final concentration of component A on the wood strands and with respect to the isocyanate. Component A of the binder composition used here can be prepared in a process comprising the following steps:

[0054] - Providing at least one, preferably at least two different compounds of the general formula (I);

[0055] - Addition of at least one sugar or sugar alcohol;

[0056] - adding at least one catalyst, in particular an acid, to the mixture of at least one compound of formula (I) and at least one sugar / sugar alcohol; and

[0057] - Precipitation and separation of the reaction mixture of at least one compound of formula (I) and at least one sugar / sugar alcohol.

[0058] Inorganic and / or organic acids suitable as catalysts are selected from a group consisting of phosphoric acid, acetic acid, p-toluenesulfonic acid, hydrochloric acid, formic acid, or sulfuric acid. Ammonium salts such as ammonium sulfate, which react as weak acids, are also suitable. p-toluenesulfonic acid is particularly preferred.

[0059] The use of sodium glycerophosphate has proven particularly suitable for precipitating the reaction mixture of at least one compound of formula (I) and at least one sugar / sugar alcohol. Other suitable precipitating agents include alkalis such as NaOH, KOH, or ammonium hydroxide solutions.

[0060] Isocyanate as component B

[0061] In one embodiment, the at least one isocyanate is based on aromatic polyisocyanates, in particular polydiphenylmethane diisocyanate (PMDI), tolylene diisocyanate (TDI) and / or diphenylmethane diisocyanate (MDI), with PMDI being particularly preferred.

[0062] In one variant, the at least one isocyanate is used in an amount of between 2 and 5 wt%, preferably between 2.2 and 4 wt%, particularly preferably between 2.5 and 3 wt% based on dry wood, in particular sprayed onto the wood strands and / or wood chips.

[0063] The present aqueous binder system preferably contains no other components besides sugar, sugar alcohol, and isocyanate. It is therefore free of formaldehyde, synthetic polyols and / or plastics, thickeners, especially polyvinyl alcohol or polyvinyl acetate, or even acrylates.

[0064] According to the invention, the binder components are sprayed onto the wood strands as separate components. Component A can be applied before, with, or after the application of the isocyanate as component B.

[0065] As mentioned above, component A is applied to the wood strands in the form of an aqueous solution. If the isocyanate used as component B were to come into contact with the aqueous solution of component A, the isocyanate would readily react with water to form polyurethane, with the resulting polyurethane depositing in the mixer and clogging the mixer's lines or spray heads. To avoid this, it is therefore advantageous to provide the binder components separately from one another according to the invention and to spray them separately onto the wood strands.

[0066] Mixer / Coil

[0067] The binder components can be applied in a gluing drum (coil) or a trough mixer.

[0068] A gluing device in the form of a coil used for the present process consists of a cylinder and at least one supply bar for the supply of adhesive and compressed air with spray discs, which are driven by pneumatic drive motors arranged in housings. Such a gluing device is described in DE 10 2008 046 637 A1.

[0069] A suitable trough mixer is available from Dieffenbacher, for example. These glue mixers ensure even glue distribution thanks to their large chamber volume and optimal material residence time. To ensure optimal gluing results, the mixer's constant fill level is maintained by an outlet flap.

[0070] After the binder components are applied to the wood strands, the glued wood strands are placed on a conveyor belt or sprinkled and then pressed into an OSB wood-based panel. Pressing can take place at a pressing temperature between 150 and 250°C, preferably between 180 and 220°C, and a pressing time between 30 and 240 seconds, preferably between 100 and 210 seconds, and especially between 150 and 180 seconds.

[0071] OSB board

[0072] According to the invention, the present process is used to produce coarse particle boards, also called OSB (oriented strand boards).

[0073] The OSB produced by the present process thus have a binder composition comprising

[0074] - at least one component A consisting of at least one silane of formula (I) and at least one sugar, at least one sugar alcohol, or a mixture;

[0075] - at least one component B comprising at least one isocyanate.

[0076] As mentioned above, particle boards, also called OSB (oriented strand boards), are made from long strands in a multi-stage process.

[0077] In a first step, strands of debarked roundwood, preferably softwood, are peeled lengthwise by rotating knives.

[0078] The wood strands produced in this way can have a length between 50 and 200 mm, preferably 70 to 180 mm, particularly preferably 90 to 150 mm; a width between 5 and 50 mm, preferably 10 to 30 mm, particularly preferably 15 to 20 mm; and a thickness between 0.1 and 2 mm, preferably between 0.3 and 1.5 mm, particularly preferably between 0.4 and 1 mm.

[0079] In one embodiment, the wood strands have, for example, a length between 150 and 200 mm, a width between 15 and 20 mm, a thickness between 0.5 and 1 mm and a moisture content of max. 50%.

[0080] As described above, OSB typically consists of two face layers that border a middle layer. The face layers and middle layer can be made of different types of wood strands. For example, flat strands can be used in the face layers, while lower-quality strands (or even chips) can be used in the middle layer. It is also possible to use different types of binder systems in the face layers and the middle layer.

[0081] In one embodiment, it may be provided that the wood strands for the top layer(s) and middle layer of the OSB are each provided with the binder system consisting of component A and component B.

[0082] It is also possible that, according to a further embodiment, only the wood strands for the middle layer of the OSB are provided with the binder system consisting of component A and component B, and the wood strands for the top layer(s) are provided only with isocyanate as a binder.

[0083] In both embodiments just described, the amount of isocyanate used in the top layer is slightly increased compared to the amount of isocyanate used in the middle layer.

[0084] Thus, the isocyanate is applied to wood strands for the covering layers in an amount of between 2.5 and 3.5 wt%, preferably between 2.7 and 3.2 wt%, particularly preferably between 2.9 and 3.0 wt%, based on dry wood.

[0085] In contrast, the amount of isocyanate applied to wood strands for the middle layer is between 2 and 3 wt%, preferably between 2.2 and 2.8 wt%, particularly preferably between 2.4 and 2.6 wt% based on dry wood.

[0086] The OSB produced using the described process has a transverse tensile strength of greater than 0.3 N / mm 2 , preferably greater than 0.4 N / mm 2 , preferably greater than 0.45 N / mm 2 , particularly preferably greater than 0.5 N / mm 2 The transverse tensile strength can be in a range between 0.3 and 0.6 N / mm 2 , preferably between 0.4 and 0.6 N / mm 2 , particularly preferably between 0.45 and 0.55 N / mm 2 lay.

[0087] Furthermore, the particleboards (OSB) produced using the described process have longitudinal elastic moduli between 3200 and 4000 MPa, preferably between 3400 and 3800 MPa, and transverse elastic moduli between 1400 and 1800 MPa, preferably between 1500 and 1600 MPa. The present OSB wood-based panel can have a bulk density between 300 and 1000 kg / m³. 3 , preferably between 500 and 800 kg / m 3, particularly preferably between 600 and 700 kg / m 3 have.

[0088] The thickness of the present OSB wood-based panel can be between 5 and 50 mm, preferably between 8 and 40 mm, with a thickness between 8 and 30 mm being particularly preferred.

[0089] The invention is explained in more detail below using several exemplary embodiments.

[0090] Example 1: Preparation of component A of the binder system

[0091] A mixture of 34.2 g of sorbitol (50 wt% in water) and 4 g of para-toluenesulfonic acid is added to a mixture consisting of 20.33 g of tetraethyl orthosilicate (0.1 mol) and 139.2 g of glycidyloxypropyltriethoxysilane (0.5 mol) while stirring. This results in hydrolysis of the silane mixture and a reaction with the sorbitol, whereby the degree of condensation is deliberately kept low. The course of the reaction and the degree of condensation are monitored using Si NMR measurements.

[0092] After stirring for 4 hours, a mixture of 136.8 g of demineralized water and 34 g of sodium glycerophosphate is added to the above reaction mixture. This mixture is stirred for a further 60 minutes.

[0093] After a rest period of approximately 1 hour, a two-phase mixture forms. The lower, now aqueous phase, containing the reaction product of silanes and sorbitol, is separated from the upper alcohol phase and used as component A.

[0094] Example 2:

[0095] On an OSB line, the top layer (DS) strands in the coil are sprayed with 2.9 wt% PMDI on dry wood. In the middle layer (MS), 2.5 wt% PMDI on dry wood is added in a trough mixer. In addition, component A is added to the middle layer (MS) in an amount of 1.6 wt% based on PMDI (0.04 wt% on dry wood). Component A was used at a concentration of 12.5%. The delivery concentration was 50 wt%. Before adding component A, a blank sample without silane component A (board thickness: 18 mm) was first taken at the maximum speed of 340 mm / sec usually specified by the quality parameters. After the silane addition began, another sample was taken. The production speed was then increased to 400 or 435 mm / sec. This was the maximum speed that could be produced for the middle layer with the available chip quantity.This corresponds to a 27% increase in line speed. Samples were taken at both speeds. Finally, a sample without silane was taken at 435 mm / sec. After cooling, the samples were analyzed for some important technological properties.

[0096]

[0097] As can be seen from the table, all samples meet the minimum transverse tensile strength of 0.3 N / mm required by DIN EN 300, 09 / 2006: Oriented strand boards (OSB) - Definitions, classification and requirements. 2for OSB 3. In terms of elastic modulus, sample 4 falls slightly short of the required values ​​(3500 and 1400 MPa), and sample 5 falls significantly short. In all cases, it can be observed that the values ​​with silane are significantly higher than the comparative values ​​without silane. The technological values ​​determined for the sample with silane at maximum speed are also still at the level of sample 1.

[0098] Example 3:

[0099] On an OSB line, the top layer (DS) strands in the coil are sprayed with 2.9 wt% PMDI on dry wood. In the middle layer (MS), 2.5 wt% PMDI on dry wood is added in a trough mixer. This OSB was produced as a blank sample. The silane-containing component A was then added to both the top layer (DS) and the middle layer (MS).

[0100] In the top layer (DS), 1.6 wt% of the silane-containing component A was dosed on PMDI (0.05 wt% on dry wood). In the middle layer (MS), 2.5 wt% of the silane-containing component A was dosed on PMDI (0.06 wt% on dry wood). The silane was used at a concentration of 12.5%. The delivery concentration was 50 wt%.

[0101] Before adding the silane, a blank sample was first taken without silane (plate thickness: 18 mm) at the maximum speed of 340 mm / sec, which is usually specified by the quality parameters. After the silane addition began, another sample was taken. The production speed was then increased to 400 or 460 mm / sec. This speed could only be produced for a short time due to the resulting lack of chips for the middle layer. However, the required samples could be taken. This corresponds to a system speed increase of 27%. Samples were taken at both speeds. Finally, an attempt was made to take another sample without silane at 460 mm / sec. However, cracks occurred there. After cooling, the samples were examined for several important technological values.

[0102] In this test, the speed was also significantly increased. At a feed rate of 460 mm / sec, OSB could no longer be produced without the GS 55. This results in advantages

[0103] - Significant increase in production volumes

[0104] - Reducing the risk of pre-curing

[0105] - Cost reduction

Claims

Patent claims 1. A method for producing an OSB wood-based panel comprising the following steps: a) providing wood strands; b) bonding the wood strands with a binder system comprising a component A comprising iii) at least one sugar, at least one sugar alcohol or a mixture thereof, and iv) at least one compound of the general formula (I) Ra 1 SiX(4-a) where - X alkoxy is - R 1 An organic residue is selected from a group comprising C1-C10 alkyl groups, which may be interrupted by -O- or -NH-. - where R 1 at least one functional group Qi selected from a group containing a methacrylic, methacryloxy, vinyl, alkoxy, amino, isocyano and epoxy group, and - a = 0, 1, 2, 3, in particular 0, 1 or 2, and a component B consisting of at least one isocyanate, wherein component A and component B are applied separately to the wood strands, c) spreading the glued wood strands onto a conveyor belt; and d) pressing the glued wood strands to form an OS B wood-based panel, and wherein the process is carried out in a production plant with an increase in plant speed of at least 10%, preferably at least 15%, particularly preferably at least 20%, even more preferably at least 25% compared to the initial speed of the production plant. A process according to claim 1, characterized in that the at least one sugar of component A is a monosaccharide from the group of pentoses and hexoses, in particular selected from the group containing arabinose, ribose, xylose, glucose (dextrose), mannose, galactose, and fructose. A process according to one of claims 1-2, characterized in that the at least one sugar alcohol of component A is selected from the group containing tetrahydric, pentahydric, and hexahydric alcohols, wherein the tetrahydric alcohols used are threitol, erythritol, and pentaerythritol; the pentahydric alcohols used are arabitol, adonitol, and xylitol; and the hexahydric alcohols used are sorbitol, mannitol, dulcite, and dipentaerythritol.A method according to any one of the preceding claims, characterized in that the residue X of the silane of formula (I) is selected from the group comprising Ci-6-alkoxy, in particular methoxy, ethoxy, n-propoxy, i-propoxy and butoxy. A method according to any one of the preceding claims, characterized in that the organic residue R. 1 The silane of formula (I) is selected from a group comprising C1-C10 alkyl, preferably C1-C8 alkyl, which may be interrupted by -O- or -NH-. A process according to any of the preceding claims, characterized in that the at least one functional group Q 1The silane of formula (I) is selected from a group comprising an epoxy group, in particular a glycidyl or glycidyloxy group, a methacryloxy group, or an isocyano group. A process according to any one of the preceding claims, characterized in that at least two silane compounds of formula (I) are used. A process according to any one of the preceding claims, characterized in that the at least one component A, consisting of silane and sugar / sugar alcohol, is applied to the wood strands in an amount between 0.01 and 0.5 wt%, preferably between 0.02 and 0.1 wt%, and particularly preferably between 0.04 and 0.08 wt% based on dry wood. A method according to any one of the preceding claims, characterized in that the at least one isocyanate is polydiphenylmethane diisocyanate (PMDI), toluene diisocyanate (TDI), and / or diphenylmethane diisocyanate (MDI). A method according to any one of the preceding claims, characterized in that the at least one isocyanate is applied to the wood strands in an amount between 2 and 5 wt%, preferably between 2.2 and 4 wt%, and particularly preferably between 2.5 and 3 wt% based on the dry wood content. A method according to any one of the preceding claims, characterized in that the wood strands for the top layer(s) and middle layer of the OSB are each provided with the binder system consisting of component A and component B.Method according to one of claims 1-10, characterized in that only the wood strands for the middle layer of the OSB are provided with the binder system consisting of component A and component B, and the wood strands for the top layer(s) are provided only with isocyanate as a binder.

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