Board material, method for manufacturing such board material, decorative panel comprising such board material, laminate and method for manufacturing said laminate

Abstract

Board material, method for manufacturing such board material, decorative panel comprising such board material, laminate and method for manufacturing said laminate, wherein use is made of glues and / or resins comprising (meth)acrylates and / or unsaturated polyesters.

Description

[0001] Board material, method for manufacturing such board material, decorative panel comprising such board material, laminate and method for manufacturing said laminate

[0002] The present invention relates to board materials and methods for manufacturing board material. The present invention also relates to decorative panels comprising said board material and methods for manufacturing such decorative panels. The present invention also relates to laminates and method for manufacturing laminates. The invention relates to floor panels, furniture panels, wall panels and construction panels.

[0003] More specifically the invention, among others, relates to a method for producing a board material, said board material comprising plant particles, for example lignocellulosic particles such as wood fibers or wood chips, wherein said method comprises at least the following steps:

[0004] -a step of providing plant particles;

[0005] -a step of providing a curable glue to said plant particles to form glued plant particles;

[0006] -a step of forming a cake comprising said glued plant particles;

[0007] -a step of pressing said cake to form said board material.

[0008] Said board material can be particle boards, oriented strand boards (OSB) and fiber boards, for example wood fiber boards such as MDF (medium-density fiberboard) or HDF (high-density fiberboard) or plant fiber boards such as flax board or hemp boards.

[0009] Said board material is manufactured by pressing, for example in a continuous press or in a discontinuous press. The pressing conditions, such as time, pressure and temperature have a major influence upon the quality of the board material. Of course the choice of the materials to form said board material also has a major influence. The internal bond, the bending strength and the density, are important characteristics. Preferably the speed of production is as high as possible. During production of said board material, there can be emissions of harmful substances, such as formaldehyde. These emissions are preferably as low as possible. Also when said board material is being used, for example is being used indoor, it is preferred that the emission of harmful substances is as low as possible. A glue often used in the production of said board material is an aminoplast polymer, produced by a polycondensation reaction from urea and formaldehyde to a urea formaldehyde glue (UF glue). Optionally melamine is added and a melamine urea formaldehyde glue (MUF glue) is obtained, or melamine and / or phenol are added, for example to obtain melamine urea phenol formaldehyde glue (MUPF glue). The great advantages of these glues are their low cost - on account of the use of generally available and cheap raw materials in their preparation and their high reactivity, such that high production speeds can be obtained. Glues of this kind may release formaldehyde during and after polymerization, under the effect of temperature, moisture, or pH change. Formaldehyde-free glues for producing the aforementioned boards have been found, but it is not possible or more difficult to obtain a sufficient speed of production and / or these formaldehyde-free glues can have safety issues and / or production issues can be present.

[0010] Formaldehyde-free glues, such as glues comprising polymeric methylene diphenyl diisocyanate (pMDI), are known.

[0011] The invention also relates to a decorative panel comprising said board material. Said decorative panels can imitate solid wood panels or stone tiles and can therefore be provided with a relief.

[0012] WO 01 / 96689 describes decorative panels comprising a board material and a top layer with a print, wherein a relief is provided in the top layer, wherein said relief preferably corresponds to the print. To this aim, for example, a press plate or other press element is manufactured, which shows a surface relief, and by means of said press plate then a relief is formed in the top layer of the decorative panel. However, the relief obtained in this manner according to the state of the art still leaves much to be desired.

[0013] The characteristics of a said decorative panel, for example the quality, depends on the quality of the board material used to make such decorative panel.

[0014] The invention also relates to laminates comprising at least two sheets. Said laminates can be used to cover up surfaces of furniture (panels) or other elements. To provide said furniture (panels) or other elements with an aesthetic look, it is important the laminate closely follows the surfaces it covers up.

[0015] The invention in the first place seeks to provide alternative board materials, alternative decorative panels comprising board material, alternative methods for producing board material, alternative laminates and alternative methods for producing laminates wherein, in accordance with preferred embodiments, a solution is provided for one or more of the problems with the board material, the decorative panel comprising board material, the method for producing board material, the laminate and the method for producing laminate of the state of the art.

[0016] The invention is described in the claims.

[0017] The description mentions weight percentages. Said weight percentages are preferably dry matter weight percentages, unless otherwise indicated.

[0018] The invention, according to a first aspect, relates to a method for producing a board material, said board material comprising plant particles, for example lignocellulosic particles such as fibers or chips, wherein said method comprises at least the following steps:

[0019] - a step of providing plant particles;

[0020] - a step of providing a curable glue to said plant particles to form glued plant particles;

[0021] -a step of forming a cake comprising said glued plant particles;

[0022] -a step of pressing said cake to form said board material; wherein the curable glue comprises one or more (meth)acrylates and / or unsaturated polyesters, and further comprises a thermo-initiator for activating unsaturated carboncarbon bonds of said one or more (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 seconds half-life of a first temperature, said first temperature preferably being between 80 °C and 250 °C, wherein the temperature of said cake during said step of pressing said cake, remains lower than said first temperature, and wherein said curable glue further comprises one or more functional endgroups, wherein said one or more functional endgroups are preferably chosen from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes or mixtures thereof; wherein said one or more functional endgroups are part of said one or more (meth)acrylates and / or unsaturated polyesters and / or are part of one or more additional molecules of the curable glue, wherein said one or more functional endgroups are activated during said step of pressing such that the board material is a semi-cured board material.

[0023] Said formed cake can be a one-layered cake, but can also comprise two, three or more layers. For example the cake can be three-layered with two outer base layers and a central base layer sandwiched between said two outer base layers. The cake can also be fourlayered, five-layered or more, with two outer base layers and two, three or more central base layers sandwiched between said two outer base layers. All of said layers can comprise said glued plant particles, with said curable glue being the glue with said thermo-initiator. However it is also possible that not all of said layers comprise said glued plant particles. For example at least one of said outer base layers can comprise said glued plant particles and said central base layer can comprise glued plant particles comprising another curable glue, e.g. a glue comprising said (meth)acrylates and / or unsaturated polyesters but not said thermo-initiator or another thermo-initiator, or a curable glue comprising a formaldehyde based glue such as a urea-formaldehyde glue or a melamine urea-formaldehyde glue or a melamine formaldehyde glue, or a bio-based glue.

[0024] The board material made according to the first aspect of the invention is a semi-cured board material. This because the temperature of the cake during this method remains below said first temperature, such that there are still unsaturated carbon-carbon bonds of said one or more (meth)acrylates and / or unsaturated polyesters. This indicates that further curing of said board material is possible. Said board material is thus a curable board material. The used glue to form said board material has said thermo-initiator. Since the temperature of the cake remains below said first temperature, said thermo-initiator retains its functionality as initiator for activating unsaturated carbon-carbon bonds of said one or more (meth)acrylates and / or unsaturated polyesters. Said board material is therefore very suitable for forming laminate panels, wherein one or more layers are laminated to said board material, for example to form so-called DPL (direct pressure laminate). Lamination can be performed at temperatures above the first temperature, thus activating said thermo-initiator. Such a board material is for example very suitable to form decorative laminate panels with a relief with deep embossments, e.g. a relief with deep embossments to imitate wood. Said embossments can then imitate wood pores, wood knots, etc. To form said laminate panels with deep embossments, use can be made of press elements with protrusions, wherein a stack of said board material and said one or more layers are pressed between said press elements. For example the laminate panel can have one decorative top layer comprising one or more sublayers, such as a resin impregnated printed paper and a resin impregnated translucent paper, wherein than a stack is formed of said board material and said decorative top layer, wherein the press element which contacts said decorative top layer is a structured press element comprising protrusions to form a relief in at least said decorative top layer. Since the board material is semi-cured when lamination is started, it has sufficient flexibility, such that the risk of pressing defects of the decorative top layer is lower. For example if said decorative top layer comprises paper sheets, the risk of unwanted tearing of said paper sheets is lower. Surprisingly, the inventors have found that the structure of the pressing element is quite favorably copied in the laminate panel. Very preferably one or more of said embossments reach into the board material, such that very deep embossments can be present. Preferably the upper surface of the board material in said decorative laminate panel than also has a relief, which preferably is in register with the decor if the decorative top layer comprises a print. Also because the board material will further cure during lamination, very strong laminate panels can be obtained, having high densities. Another advantage of this board material is that the further curing of the board material during lamination does not increase the moisture content, since no water is released when curing doubledouble carbon bonds. For board material comprising two or more layers, such as a threelayered board material, one can choose to form only one outer base layer or both outer base layers with said glued plant particles comprising said curable glue with said thermoinitiator, since the decorative top layer will be laminated upon a said outer base layer of the board material. Thus the curable glue of the glued plant particles of the one or more central outer base layers could have a curable glue comprising (meth)acrylates and / or unsaturated polyesters and a second thermo-initiator with a 60 seconds half-life of a second temperature which is lower than said first temperature and / or can comprise an UF, MUF or melamine formaldehyde (MF) glue, as such that said one or more central base layers get fully cured or at least more cured during said step of pressing. As such the board material can have sufficient rigidity.

[0025] The temperature of said cake during said step of pressing said cake, remains lower than said first temperature. Preferably this is obtained by making use of one or more press elements which have a maximum temperature during said step of pressing said cake, which is lower than said first temperature. For example a said press element can be heated to a maximum temperature which is lower than said first temperature. Preferably at least the average temperature of said cake during said step of pressing said cake, remains lower than said first temperature. More preferably, the maximum temperature reached in said cake during pressing remains lower than said first temperature.

[0026] The invention according to the first aspect is preferably a method for producing a board material, said board material comprising plant particles, wherein said method comprises at least the following steps:

[0027] - a step of providing plant particles;

[0028] - a step of providing a curable glue to said plant particles to form glued plant particles; -a step of forming a cake comprising said glued plant particles;

[0029] -a step of heat pressing said cake to form said board material, and this with a pressing device comprising one or more press elements, wherein the curable glue comprises one or more (meth)acrylates and / or unsaturated polyesters, and further comprises a thermo-initiator for activating unsaturated carboncarbon bonds of said one or more (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 seconds half-life of a first temperature, said first temperature preferably being between 80 °C and 250 °C, wherein the maximum temperature of said one or more pressing elements during said step of heat pressing said cake remains lower than said first temperature, preferably remains at least 10 °C lower than said first temperature, and wherein said curable glue further comprises one or more functional endgroups, wherein said one or more functional endgroups are preferably chosen from the list of isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes and siloxanes, or combinations thereof; wherein said one or more functional endgroups are part of said one or more (meth)acrylates and / or unsaturated polyesters and / or are part of one or more additional molecules of the curable glue, wherein said one or more functional endgroups are activated during said step of heat pressing said cake, such that the board material is a semi-cured board material.

[0030] The plant particles of the first aspect of the invention are preferably lignocellulosic particles, more preferably wood particles, such as wood fibers and / or wood chips and / or wood shavings. Said plant particles can comprise wood chips, such that a particle board material is produced. Said plant particles can comprise fibers, such as wood fibers, such that a fiberboard material is produced, for example MDF (medium density fiberboard) or HDF (high density fiberboard).

[0031] Said plant particles can be obtained from fresh plants, e.g. fresh wood, but can also comprise a certain amount of recycled material or can only comprise recycled material. For example at least a part of said plant particles can be obtained from production waste or post-consumer products comprising particle board, wood fiber board, solid wood, etc. Said recycled material can comprise fibers obtained from recycling wood fiberboard containing material, such as medium density fiberboard (MDF) or high density fiberboard (HDF), for example by a process as described in WO 2021 / 176326. Said recycled material can comprise comminuted particles derived from particle board containing material. Said recycled material can comprise comminuted particles from old solid wood containing products. Said plant particles can also be coated plant particles, e.g. plant particles which have been coated with a water resistant glue / coating.

[0032] Said curable glue comprises one or more (meth)acrylates and / or unsaturated polyesters, and further comprises a thermo-initiator for activating unsaturated carbon-carbon bonds of said one or more (meth)acrylates and / or unsaturated polyesters. Further said one or more functional endgroups are present. This curable glue is preferably free from formaldehyde and / or preferably free from melamine and / or preferably free from phenol. The curable glue is preferably free from formaldehyde, melamine and phenol. Said curable glue does therefore not negatively influence emissions of harmful elements. If said curable glue comprises (meth)acrylates, it can be indicated as a (meth)acrylate glue. If said curable glue comprises unsaturated polyesters, it can be indicated as an unsaturated polyester glue.

[0033] With (meth)acrylates can be indicated methacrylates and / or acrylates. Preferably, one works with acrylate monomers and / or oligomers, since these are more reactive than methacrylate monomers and oligomers. Said (meth)acrylates can only comprise oligomers or can comprise between 5 and 80 wt% of oligomers. Said (meth)acrylates can comprise monomers.

[0034] Preferably, the one or more (meth)acrylates are of the aliphatic type. Aging and / or discoloration are limited with such (meth)acrylates.

[0035] Preferably, the one or more (meth)acrylates comprise 5 to 80 percent by weight of monomers, or more preferably 5 to 60 percent by weight. Said monomers can be monofunctional, difunctional or multifunctional. Monomers can have one or more of the following effects: increasing the viscosity of the glue to the desired value. For this purpose, for example, a trifunctional monomer such as trimethylolpropane triacrylate (TMPTA) can be used. With difunctional monomers, in view of the short chain length, promotion of the crosslinking and curing can also be achieved. For example, DPGDA (dipropylene glycol diacrylate) monomer can be used, with a sufficient flow being obtained during curing.

[0036] The (meth)acrylates can be a mixture of two or more acrylate oligomers of different functionality. Said mixture can or cannot comprise acrylate monomers.

[0037] In this document, an unsaturated polyester resin refers to a polyester that is unsaturated and can be cured by crosslinking of the double bonds in the unsaturated polyester.

[0038] The glue can or cannot comprise a solvent, for example a butyl acetate or propyl acetate. The glue can comprise between 0.1 to 5 wt% of said thermo-initiator.

[0039] If said additional molecules are present, these are preferably present in an amount of between 1 and 5 wt%.

[0040] Said functional endgroups can be part of said one or more (meth)acrylates and / or unsaturated polyester. For example use can be made of a (meth)acrylate with a polyurethane backbone and at least two acrylate endgroups, said backbone comprising one or more isocyanate endgroups. Use can also be made of a (meth)acrylate with a polyester backbone and at least two acrylate endgroups, said backbone comprising one or more of said functional endgroups. Use can also be made of a (meth)acrylate with an epoxy backbone or a polyether backbone and at least two acrylate endgroups.

[0041] Said functional endgroups can also be part of additional molecules. For example said additional molecules can comprise both epoxide, such as di-epoxide, and amine. Such additional molecules can be indicated as an epoxy / hardener system. A glue comprising one or more (meth)acrylates, an epoxy / hardener system and a thermo-initiator, is a very suitable glue for this method. Said additional molecules can also comprise both carbodiimide and aziridine.

[0042] During pressing, said functional endgroups will react with the hydroxyl groups of the plant particles, e.g. the hydroxyl groups of the wood, as such forming a bound between the plant particles and the glue.

[0043] Pressing is preferably done with a pressing device, such as a continuous double belt press or a single daylight press or a multidaylight press. Pressing devices make use of one or more pressing elements. Preferably at least on of said pressing elements is heated and / or heat is added during pressing. The pressing then comprises heat pressing. Before heat pressing, there can also be prepressing. For example, for heat pressing, the temperature of at least one of said press elements is at least above 20 °C, preferably at least 30 °C, more preferably at least 40 °C, most preferably at least 50 °C. The temperature of said press elements is preferably at most 150 °C, more preferably below 120°C, most preferably below 100 °C, such that it is ensured that that the temperature of the cake remains below the first temperature. For example the maximum temperature of a said press element is preferably between 80°C and 100°C. Use can also be made of different temperature zones. For example use can be made of a continuous double belt press with two or more zones having different temperatures, but preferably all having temperatures below the first temperature. To semi-cure the cake, heat is not needed. However by adding heat, pressing times can be reduced. Pressing can take place with pressing times between 2 and 10 seconds per mm thickness formed board material. The pressure during pressing is preferably at most 70 bar or between 20 and 60 bar.

[0044] Another benefit of said board material is that it can be used to form laminate panels with increased waterproof characteristics with respect to laminate panels having board material comprising conventional ureaformaldehyde glues.

[0045] Also with the aid of (meth)acrylates and unsaturated polyesters, the characteristics of the board material can be altered depending on the used (meth)acrylates and unsaturated polyesters. For example the flexibility of the board material can be increased if the chain length of the (meth)acrylates and unsaturated polyesters is increased. Preferably said (meth)acrylates comprise at least (meth)acrylate oligomers. Also, if said board material is used to form laminate panels at a temperature higher than said first temperature, said chain lengths will also influence the flexibility of the formed laminate panels. For example use can be made of a difunctional (meth)acrylate and a monofunctional (meth)acrylate to have laminate panels comprising said board material which are more flexible. For example use can be made of trifunctional, tetrafunctional or pentafunctional or hexafunctional (meth)acrylates. The higher the functionality of the (meth)acrylates, the stronger the laminate panel comprising said board material can be.

[0046] Said (meth)acrylates can be urethane, epoxy, polyester, polyether (meth)acrylates and / or can be reactive acrylate diluents or can be mixtures thereof.

[0047] Said functional endgroups preferably comprise at least isocyanate. Isocyanate is very reactive, even at low temperatures. A thermo-initiator can more generally be defined as a thermally unstable molecule that breaks down or disintegrates on exposure to heat, at least in one or more radicals. The radicals produced then play the same role as the radicals that are produced in known photo-initiators in the UV curing of acrylate resins. The thermally obtained radicals initiate the polymerization reaction of the double carbon bonds of the acrylate functionalities present in the acrylate resin.

[0048] Preferably the temperature of said cake during said step of pressing said cake, remains at least 10°C lower than said first temperature. As such disintegration of the thermoinitiator is avoided.

[0049] Preferably the thermo-initiator has a 60 seconds half-life of between 100°C and 180°C, more preferably between 120°C and 170°C.

[0050] The thermo-initiator is preferably a peroxide. For example the thermo-initiator is a benzoyl peroxide, such as dibenzoyl peroxide which has a 60 second half-life of approximately 131 °C, or a tert-butylperoxy-hexane, such as 2-5-Dimethyl-2-5-di-tert- butylperoxy-hexane (DHBP). The thermo-initiator can be a peroxycarbonate, such as OO-tert-amyl-O(2-ethylhexyl)-monoperoxy carbonate which has a 60 second half-life of approximately 155° C. Other possibilities are methylbenzoyl peroxide, 2-butanone peroxide, persulfate, peroxydiphosphate and persulfate, ketone peroxide, diacyl peroxide, peroxyketal, hydroperoxide, peroxydicarbonate, peroxymonocarbonate, preferably tert-butyl peroxy 3,5,5 trimethyl hexanoate (TPBIN).

[0051] In addition to peroxides, or as an alternative to peroxides, the thermo-initiator can also be an azo-polymerization initiator, such as azonitrile, azoester, hyponitrites and / or azoamide. As a specific example, one can use azobisisobutyronitrile (AIBN), 2- methylbutyronitrile (AMBN), azovaleronitrile (AVN).

[0052] Of course, said glue can comprise a combination of two or more thermo-initiators, for example two or more of the above-mentioned thermo-initiators. Preferably said pressing takes place at a temperature which remains lower than the 60 seconds half-life temperature of each said thermo-initiator.

[0053] Preferably, the glue comprises between 0.1-5 parts, more preferably between 1 and 5 parts and most preferably between 3.5 and 4.5 parts of thermo-initiator per 100 parts of said one or more (meth)acrylates and / or one or more unsaturated polyesters. By increasing the concentration of the thermo-initiator, the obtained board material is more reactive.

[0054] In a very preferred embodiment, the curable glue comprises one or more (meth)acrylates, and wherein said one or more (meth)acrylates comprise said one or more functional endgroups, for example isocyanate endgroups. For example, a very suitable glue is a (meth)acrylate with a backbone comprising isocyanate endgroups, for example a bifunctional (meth)acrylate with a polyurethane backbone comprising at least two isocyanate endgroups.

[0055] Preferably the curable glue comprises one or more (meth)acrylates and said one or more (meth)acrylates have at least an acrylate functionality of two.

[0056] Said (meth)acrylates can comprise polyester acrylate oligomers which comprise or consist of polyester acrylate oligomers having an acrylate functionality of at least 3 and / or said (meth)acrylates can comprise polyester methacrylate oligomers which comprise or consist of polyester methacrylate oligomers having a methacrylate functionality of at least 3.

[0057] In the context of this document, the acrylate or methacrylate functionality of a compound is the number of respectively acrylate or methacrylate groups per molecule of the compound. The acrylate functionality of a compound comprising different types of molecules not necessarily having the same acrylate (or methacrylate) functionality is determined as the molar based weighed average. In a specific embodiment the glue comprises said one or more additional molecules, wherein said one or more additional molecules are preferably selected from the list of isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes or mixtures thereof.

[0058] Preferably the glue comprises one or more (meth)acrylates, wherein said one or more (meth)acrylates comprise, and preferably consist of, oligomers selected from the group consisting of polyester acrylates and polyester methacrylates, or mixtures thereof, preferably wherein said oligomers have a molar mass equal to or higher than 800 g / mol and lower than 7000 g / mol;

[0059] Said pressing preferably takes place at a temperature of at most 150 °C, preferably at a temperature of between 80 °C and 120 °C, for example of between 90 °C and 100 °C. Preferably a continuous double belt press is used for said step of pressing, wherein the maximum temperature of the belts of said continuous double belt press is at most 150 °C, preferably at most 120°C and / or wherein the pressure applied by said continuous double belt press is between 20 and 150 bar.

[0060] Preferably pressing takes place between 3 and 7 seconds per mm thickness of formed board material.

[0061] For the glued plant particles, the dry matter weight ratio of glue:plant particles is preferably between 2: 100 and 15: 100, for example between 5: 100 and 10: 100.

[0062] According to a first variant of the first aspect of the invention, the pressing of said cake comprises heat pressing of said cake, and wherein the temperature of said cake during said heat pressing said cake, reaches a temperature above said first temperature. The result is a substantially fully cured, or an at least more cured, board material. The benefit here is mainly that said curable glue does not have to comprise formaldehyde. Also said (meth)acrylate glues or said unsaturated polyester glues have the benefit that no and / or less water is released during curing of said glue, such that there is less formation of steam during heat pressing. With the aid of this first variant, the characteristics of the board material can be the result of the chain length of the used (meth)acrylates and / or unsaturated polyesters, such that a board material with the desired flexibility can be obtained.

[0063] The invention, according to a second aspect, relates to a board material comprising plant particles, for example lignocellulosic particles, wherein said plant particles have been pressed and bonded together with a curable glue, wherein said curable glue comprises one or more (meth)acrylates and / or unsaturated polyesters, and further comprises a thermo-initiator for activating unsaturated carbon-carbon bonds of said one or more (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 seconds half-life of a first temperature, said first temperature preferably being between 80 °C and 250 °C, and wherein said curable glue further comprises one or more functional endgroups, wherein said one or more functional endgroups are preferably chosen from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes, or combinations thereof; wherein said one or more functional endgroups are part of said one or more (meth)acrylates and / or unsaturated polyesters and / or are part of one or more additional molecules of the curable glue.

[0064] Said board material can be manufactured according to the method of the first aspect of the invention. Therefore all the preferred embodiments of the first aspect of the invention apply mutatis mutandis for the second aspect of the invention and vice versa.

[0065] Preferably said board material is a semi-cured board material with unbound thermoinitiator and preferably bonds between one more of said one or more functional endgroups and plant particles. Here the curable glue is not fully cured yet, e.g. the thermo-initiator is unbound and as such has not activated the unsaturated carbon-carbon bonds of said one or more (meth)acrylates and / or unsaturated polyesters. Here only the functional endgroups have reacted with the plant particles as such to bound the glue and the plant particles together to form a board material. Such a board material is very suitable to be used for further processing steps, e.g. the board material can be used to form a laminate panel, wherein said board material then preferably forms at least part of the substrate and preferably forms the substrate, of the laminate panel. Since the board material is semi-cured, it can be further cured in said further processing steps, as such obtaining a very strong laminate panel and / or a laminate panel with a relief having deep embossments. Said board material is therefore very suitable for forming laminate panels as disclosed in the first aspect of the invention, for example laminate panels wherein one or more layers are laminated to said board material, for example to form so-called DPL.

[0066] Preferably the average density of the board material is between 500 and 900 kg / m3, for example 750 kg / m3. Such a board material, if it is semi-cured, can be further compressed and further cured, resulting in an increased density. For example such a board material can be used to form the substrate of a laminate panel, wherein to form said laminate panel, heat pressing at a temperature higher than the first temperature can be used, resulting in a substrate with a density of between 750 and 1300 kg / m3, for example 1100 kg / m3.

[0067] The invention, according to a third aspect, relates to a method for producing a decorative panel, wherein at least a decorative top layer is laminated to a surface of a board material by heat pressing, wherein a board material according to second aspect or produced according to the first aspect, is provided and wherein said board material during said heat pressing, at least at the height of said surface, reaches a temperature which is at least higher than the first temperature, such as to activate said thermo-initiator and to further cure the glue of the board material.

[0068] Here the heat pressing takes place at a temperature above the first temperature, for example for a certain amount of time, the temperature is between 180°C and 225 °C, for example is between 190°C and 200°C. Such heat pressing preferably takes place in a discontinuous pressing device, such as a single daylight press or a multi daylight press. Of course a continuous pressing device could also be used. The used pressure can be between 5 to 80 bar, for example 40 bar. Pressing times, if a single daylight press is used, can be between 10 and 60 seconds, for example 22 seconds. Said decorative top layer preferably comprises one or more sublayers, with at least one decorative sublayer. Said decorative sublayer can for example comprise a printed sheet, such as a printed paper. Said decorative sublayer can also be uniformly coloured sheet, such as a uniformly coloured paper. Said papers can be impregnated and / or coated with a resin / coating / lacquer or with two or more resins / coatings / lacquers. Said resins can be thermosetting resins. Useful resins are formaldehyde resins, such as melamine formaldehyde resins, or acrylate resins, or unsaturated polyester resins. Examples of possible resins / coatings / lacquers are described in WO 2020 / 095196 and WO 2021 / 009584 and are incorporated by reference. Preferably a said printed paper is at least a resin impregnated paper, possibly having an additional coating / lacquer. Said decorative top layer can also be a direct print, being a print directly applied upon said board material, and this with or without a primer in between the print and the board material. Said decorative top layer can also be a veneer. Additionally said decorative top layer can comprise a wear sublayer, e.g. a translucent sheet such as a resin impregnated translucent paper and / or an additional coating / lacquer. The resin of the wear sublayer can be the same resin as described above and / or can comprise hard particles such as corundum or aluminum oxide.

[0069] Preferably a said pressing device has one or more structured press elements to provide at least said decorative top layer with a relief, for example a relief which matches the print of the decorative top layer if the decorative top layer comprises a print. Since the board material is semi-cured, the decorative top layer can very well copy the structure of said structured press elements and there is less risk of pressing defects, e.g. tearing of the paper and / or poorly cured resin. With the aid of this method, decorative panels with deep embossments can be created, e.g. embossments which go into the board material, such that the surface of the board material upon which the decorative top layer is laminated, also shows a relief. Alternatively or additionally use can be made other techniques, such as excimer curing and / or digital printing, to provide the decorative top layer with the desired relief.

[0070] Preferably, for said heat pressing, said board material and said decorative top layer are placed on top of each other and pressed between press elements, wherein at least said press element which contacts said decorative top layer comprises protrusions to provide the decorative top layer with a relief, wherein at least one protrusion has a minimum height of at least 1 mm. Said press element can directly or indirectly contact said decorative top layer. For example said press element can directly contact said decorative top layer or use can be made of an intermediate element, such as a foil, wherein said foil directly contacts said decorative top layer. Said foil can also be a structured foil. The result is then a decorative panel, wherein said decorative panel comprises one or more pores with a minimum height of at least 1 mm, wherein said pores preferably extend into the board material, and thus extend below a global upper surface of the board material.

[0071] The decorative panel made according to the third aspect of the invention can comprise a balancing layer, wherein said decorative top layer and said balancing layer are located on opposite sides of the board material. The latter is beneficial if the decorative top layer comprises a resin which is curable by polycondensation. Said balancing layer can comprise a resin impregnated paper, or only a resin.

[0072] The decorative panel made according to the third aspect of the invention can comprise two decorative top layers which are located on opposite sides of the board material. Said two decorative top layers can or cannot have the same composition and / or look. The latter is beneficial for furniture panels of which both sides are visible. If both said decorative top layers comprise a relief, said board material according to the second aspect of the invention is very useful, since reliefs can be provided on both sides of the decorative panel with lower risk of press defects and better copying of the structure of press elements.

[0073] The invention, according to a fourth aspect of the invention, relates to a method for producing a board material, said board material comprising plant particles, for example lignocellulosic particles such as fibers or chips, wherein said method comprises at least the following steps:

[0074] - a step of providing plant particles;

[0075] - a step of providing a curable glue to said plant particles to form glued plant particles;

[0076] - a step of forming a cake comprising said glued plant particles; - a step of pressing said cake to form said board material, wherein the curable glue comprises (meth)acrylates and / or unsaturated polyesters, and further comprises a photoinitiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters, wherein before and / or during the step of pressing said cake, said curable glue is exposed to radiation, such that curing of said glue is enhanced. For example the curable glue can be exposed to radiation before the pressing starts, such as to enhance curing of said glue.

[0077] Said formed cake can be a one-layered cake, but can also comprise two, three or more layers. For example the cake can be three-layered with two outer base layers and a central base layer sandwiched in between said two outer base layers. The cake can also be fourlayered, five-layered or more, with two outer base layers and two, three or more central base layers sandwiched in between said two outer base layers. All of said layers can comprise said glued plant particles, with said curable glue being the glue with said photoinitiator. However it is also possible that not all of said layers comprises said glued plant particles, for example that a said central base layer comprises said glued plant particles with said photo-initiator, and that said outer base layers comprise glued plant particles with another curable glue, e.g. a glue comprising (said) (meth)acrylates and / or unsaturated polyesters but not said photo-initiator or a curable glue comprising a formaldehyde based glue such as a urea-formaldehyde glue or a melamine ureaformaldehyde glue or a melamine formaldehyde glue.

[0078] The major benefit of this method is that curing already starts before pressing and / or is enhanced during pressing, such that pressing parameters can have lower values. For example pressing times can be reduced and / or lower pressures can be used and / or lower temperatures can be used. Especially the reduction of pressing time ensures that manufacturing said board material can be optimized.

[0079] Pressing is preferably done with a pressing device, such as a continuous double belt press or a single daylight press or a multidaylight press. Pressing devices make use of one or more pressing elements. Preferably at least on of said pressing elements is heated and / or heat is added during pressing. The pressing is then heat pressing. For example the temperature of at least one of said press elements is at least 20 °C, preferably at least 30 °C, more preferably at least 40 °C, most preferably at least 50°C. Pressing can take place with pressing times between 2 and 10 seconds per mm thickness formed board material. The pressure during pressing is preferably at most 70 bar or between 20 and 60 bar.

[0080] Said (meth)acrylates and / or unsaturated polyesters are preferably the meth(acrylates) and / or unsaturated polyesters described in the first aspect of the invention. For example the glue comprises (meth)acrylates consisting of oligomers or consisting of oligomers and reactive acrylate diluents or consisting of oligomers and monomers.

[0081] Radiation can take place at one or more places during said method. Said radiation preferably takes place before the step of pressing said cake. For example radiation can be applied at one or more of the following:

[0082] -to the curable glue before providing said curable glue to said plant particles;

[0083] -to the curable glue and / or the glued plant particles during the step of providing said curable glue to said plant particles to form glued plant particles;

[0084] -to the glued plant particles before the step of forming the cake, for example during scattering of said glued plant particles to form said cake;

[0085] -to the cake;

[0086] -if a combination of prepressing and heat pressing is used, between prepressing and heat pressing. Prepressing is used to bring the cake in a more compacted state, as such to be able to efficiently perform heat pressing.

[0087] For example if the plant particles are wood chips and / or wood fibers, glue can be provided to the plant particles by bringing the glue and the plant particles in a gluing unit, such as a glue coater or a blowline. Said cake can be formed by scattering said glued plant particles upon a belt of a pressing device, such as a double belt pressing device, or upon a transport belt which feeds said cake to a pressing device. Radiation can for example be present inside said gluing unit and / or radiation can be applied when said glued plant particles leave said gluing unit and / or when said glued plant particles are scattered to form a said cake. The latter radiation can be UV radiation, since sufficient space is still present between said glued plant particles for the UV radiation to reach a sufficient amount of glued plant particles. Said radiation can also be electron beam, which can more easily penetrate deeply. Most preferably said radiation is applied upon said glued plant particles during scattering, such that curing of said glue is not started to soon and a good coherent board material can be formed by pressing. An example of a very preferred embodiment is an embodiment to form a three-layered particle board material or a three-layered wood fiberboard material having a central layer sandwiched between two outer layers. To form said board material, at least three subsequent scatterers are used to scatter glued wood chips / wood fibers, as such forming a cake with a least two outer base layers and a central base layer sandwiched between said two outer base layers. In this very preferred embodiment only said glued wood chips / wood fibers which will form said central base layer can be exposed to radiation during scattering of said central base layer. During pressing, said central base layer will more slowly heat and / or be exposed to pressure, such that it is beneficial that curing of the curable glue of said central base layer starts before pressing. A further benefit is that only the curable glue of said central base layer needs to comprise said photo-initiator.

[0088] Said photo-initiator can be present in said curable glue in an amount of 0.1 to 10 percent by weight, preferably 1 to 10 percent by weight. The photo-initiator can be chosen from the list of: hydroxyacetaphenones, acetophenones, aminoacetophenones, phosphine oxides, benzophenones, thioxanthones, benzoylformate or polymeric photo-initiators. The photo-initiator can for example be benzophenone or a phosphine oxide such as diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide. Such a composition can further also comprise an amine synergist, for example 1 to 10 percent by weight. Such a synergist promotes the radicle curing.

[0089] Furthermore, the curable glue can optionally comprise a UV absorber, for example 0.1 to 5 percent by weight, preferably 1 to 2%, or 1.5%. As aUV absorber, 2-hydroxyphenyl- s-triazine, possibly with a content of 15-25% of 2-methoxy-l-propyl-acetate (for example BASF Tinuvin 477) can be used, or bis(l,2,2,6,6-pentamethyl-4-piperidyl) sebacate with a content of methyl l,2,2,6,6-pentamethyl-4-piperidyl sebacate (for example BASF Tinuvin 292). The latter is beneficial if UV radiation is used. For the glued plant particles, the dry matter weight ratio of glue:plant particles is preferably between 2: 100 and 15: 100, for example between 5: 100 and 10: 10.

[0090] This method according to the fourth aspect, can be according to the first aspect of the invention. Here at least said functional endgroups and said thermo-initiator of the first aspect of the invention is present. The result is than a semi-cured board material with the desired strength. The amount of radiation can be controlled very accurately, for example by adjusting the time of radiation and / or the time the glue is exposed to radiation and / or by subjecting only a part of the glue to radiation, such that the amount of curing can be chosen as desired. For example radiation can be applied during forming of said cake, wherein to form said cake, glued plant particles are scattered, wherein only some of said scattered glued plant particles are exposed to radiation.

[0091] This method according to the fourth aspect, can be according to the first variant of the first aspect of the invention.

[0092] In a very preferred embodiment of the fourth aspect of the invention, the curable glue further comprises a thermo-initiator, wherein said thermo-initiator has a 60 second half- life of a first temperature, said first temperature preferably being between 50 °C and 250 °C, wherein said pressing comprises heat pressing and wherein the maximum temperature of said cake during said step of pressing is higher than said first temperature. Here very rapid curing can take place, since curing is not only induced by radiation but also by heat. Further preferably the cake, over its entire thickness, reaches a temperature above said first temperature and / or use is made of a pressing device comprising one or more pressing elements of which at least one pressing element reaches a maximum temperature above said first temperature. Said thermo-initiator can be a thermo-initiator as indicated in the first aspect of the invention.

[0093] In a preferred embodiment said curable glue further comprises functional endgroups, wherein said functional endgroups are part of said (meth)acrylates and / or unsaturated polyesters and / or are part of additional molecules of the glue and wherein preferably said functional endgroups are chosen from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes, or combinations thereof.

[0094] In a specific embodiment the curable glue comprises one or more (meth)acrylates, wherein said one or more (meth)acrylates comprise oligomers selected from the group consisting of polyester acrylates and polyester (meth)acrylates, or mixtures thereof, preferably wherein said oligomers have a molar mass equal to or higher than 800 g / mol and lower than 7000 g / mol.

[0095] In a specific embodiment the curable glue comprises one or more (meth)acrylates, wherein said one or more (meth)acrylates comprise acrylate reactive diluents, said reactive diluents having a molar mass lower than 900 g / mol, and preferably lower than 500 g / mol.

[0096] In a specific embodiment said curable glue comprises one or more functional endgroups, wherein said one or more functional endgroups are preferably chosen from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes and siloxanes, or combinations thereof; wherein said one or more functional endgroups are part of said one or more (meth)acrylates and / or unsaturated polyesters and / or are part of one or more additional molecules of the curable glue. With the aid of said functional endgroups, additional bonds are created and excellent bounding between the plant particles and the glue can be obtained, such that a very strong board material can be obtained.

[0097] The invention, according to a fifth aspect, relates to a board material obtained by a method according to the fourth aspect. Said board material will comprise said photoinitiator in bonded condition. Said board material can have excellent tensile strength and bending strength.

[0098] According to a second variant of the first, second, third, fourth and fifth aspect of the invention, said plant particles can be completely or at least partially replaced by alternative particles which are for example less prone to swelling, for example ceramic particles, plastic particles or metallic particles. For example the weight ratio alternative particles:plant particles can be between 1 :2 and 1 :20, for example can be 1 :4 or 1 :8 or 1 : 12. A first example of such a second variant, is a board material wherein all the plant particles are replaced by a mineral, for example by mineral fibers. Said mineral can be magnesium oxide. A second example of such a second variant, is a board material wherein the plant particles are partially replaced by a mineral, for example by mineral fibers. Said board material can comprise a combination of magnesium oxide and wood fibers.

[0099] The invention, according to sixth aspect, relates to a method for manufacturing a laminate, said laminate comprising two or more sheets and one or more resins, wherein at least one of said one or more resins is a first resin, wherein the method comprises a lamination step wherein a stack of two or more sheets is formed and pressed together to laminate said sheets together, wherein said two or more sheets in said stack are impregnated and / or coated with said one or more resins and / or wherein said one or more resins in said stack are provided between two consecutive sheets of said two or more sheets, wherein the first resin comprises (meth)acrylates and / or unsaturated polyesters, and wherein said first resin further comprise functional endgroups, wherein said functional endgroups are preferably chosen from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes, or combinations thereof; wherein said functional endgroups are part of said (meth)acrylates and / or unsaturated polyesters and / or are part of additional molecules of the first resin, wherein said functional endgroups are activated during said lamination step and wherein the first resin further comprises:

[0100] -a photo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters; and / or

[0101] -a thermo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 second half-life of a first temperature, said first temperature preferably being between 80 °C and 250 °C, wherein the maximum temperature of said stack during said lamination step remains lower than said first temperature. The result of this method is a laminate of which said first resin is not fully cured, e.g. is semi-cured. The laminate is thus a semi-cured laminate. Said laminate can thus have some flexibility and / or can be further cured when desired. For example said laminates can be used to cover up surfaces of furniture panels, decorative elements or other elements of, e.g. walls, bars, stair parts, etc. These surfaces can or cannot be flat and / or can comprise corners. For the laminate to be able to cover said surface or surfaces up in a good manner, it is important that it can smoothly follow said surface or surfaces. Conventional laminates, such as high pressure laminates (HPL), can only be used to cover up certain surfaces, for example flat surfaces, or slightly curved surfaces. Such conventional HPL can for example comprise, from bottom to top, three resin impregnated kraft papers, a resin impregnated decor paper and a resin impregnated translucent paper. Said resins of said conventional laminates can comprise phenol formaldehyde resin and / or melamine resins. Since the laminates made by the method according to the sixth aspect of the invention, are semi-cured, the can be more flexible and can be applied to more types of surfaces and then further cured, e.g. by the application of heat if a said thermo-initiator is present and / or by the application of radiation if a said photo-initiator is present. By further curing, it is also ensured that the laminate during its use, remains to follow the shape of the said surface or surfaces.

[0102] Said first resin is preferably free from formaldehyde and / or phenol and / or melamine. More preferably said first resin is free from formaldehyde, phenol and melamine. Said laminate can thus be free from, or at least contain less, formaldehyde and / or phenol and / or melamine.

[0103] For example if said first resin comprises said photo-initiator, said laminate, after appliance upon said surface or surfaces, can exposed to radiation, for example UV radiation or electron beam radiation, preferably electron beam radiation since this can penetrate more deeply into the laminate. Use can be made of a room with radiation, which can for example be present in an industrial environment, or use can be made of a handheld device or the like which can form a radiation beam. For example if said first resin comprises said thermo-initiator, said laminate, after appliance upon said surface or surfaces, can exposed to heat such that the temperature of the laminate increase above said first temperature, for example with the aid of near infrared light or hot air. For example use can be made of an oven or of a handheld device or the like which can emit heat.

[0104] Preferably in said stack, said sheets are resin impregnated sheets. A said sheet can be impregnated with one or more of said resins, for example with the aid of an impregnation bath. Of course additional coating with one or more of said one or more resins is possible. Said sheets can thus be coated resin impregnated sheets.

[0105] At least some production steps of said laminate can be done in a continuous manner. For example, one or more base sheets can be placed on top of each other, for example unrolled on top of each other, and continuously laminated to form a base laminate, which can then later be rolled up and / or shopped into smaller laminates.

[0106] At least some production steps of said laminate can be done in a discontinuous manner. For example sheets can placed on top of each other to form a stack, wherein said stack is pressed in a single daylight press or a multidaylight press. For this, one of more base sheets can be treated with said on ore more resins, after which said base sheets are cut / chopped into smaller sheets, and a stack is formed with said smaller sheets.

[0107] Said sheets are preferably chosen from the list of: papers, cardboards, textiles, glass fiber sheets. Said sheets can be the same sheets, or can be different sheets. Preferably said sheets are paper sheets, wherein said laminate then comprises at least one decorative paper, for example a printed paper or a uniformly coloured paper, and at least one structural paper, such as a kraft paper. Optionally said laminate can comprise a translucent / transparent paper which forms a wear layer which covers up the decorative paper, which is preferably part of a decorative layer. Preferably two or three structural papers are present. Said stack can thus comprise, from top to bottom, optionally a resin impregnated translucent / transparent paper, a resin impregnated decorative paper, two or three or four resin impregnated kraft papers. Preferably at least said kraft papers are impregnated with said first resin.

[0108] If other resins then said first resin are present, said other resins are preferably acrylate resin and / or unsaturated polyester resin, which comprise (math)acrylates and / or unsaturated polyesters. Said other resins can also be melamine formaldehyde resins or the like. If other resins are present, these are preferably located in a decorative top layer of said laminate, such that the visible side of the laminate remains the same after the further curing of said semi-cured first resin, and the laminate remains to have the desired appearance.

[0109] In a preferred embodiment, the laminate is a decorative laminate comprising at least one decorative sheet and at least one structural sheet, wherein in said stack, said structural sheet is at least impregnated and / or coated with said first resin.

[0110] Further preferably the laminate comprises a decorative top layer with at least said decorative sheet and a structural layer with at least said one structural sheet, wherein said decorative top layer comprises a second resin different from said first resin, preferably wherein the second resin comprises (meth)acrylates and / or unsaturated polyesters and a thermo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 seconds half-life of a second temperature, wherein the maximum temperature of said stack during said lamination is higher than said second temperature. Here said decorative top layer can be substantially fully cured after said lamination step. This ensures that the aesthetic look of the laminate will remain, even when further curing steps are performed upon the laminate. In the lamination step use can be made of structured press elements to provide the laminate with the desired relief and / or use can be made of further press elements and / or other techniques, such as excimer curing and / or digital printing, to provide the laminate with the desired relief.

[0111] The invention, according to a seventh aspect, relates to a laminate being made up of at least two sheets which are laminated together with one or more resins, wherein at least one of said one or more resins is a first resin, wherein the first resin comprises (meth)acrylates and / or unsaturated polyesters, and wherein said first resin further comprise functional endgroups, wherein said functional endgroups are preferably chosen from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes, or combinations thereof; wherein said functional endgroups are part of said (meth)acrylates and / or unsaturated polyesters and / or are part of additional molecules of the first resin, wherein the first resin further comprises:

[0112] -a photo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters.; and / or

[0113] -a thermo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 second half-life of a first temperature, said first temperature preferably being between 80 °C and 250 °C; wherein said first resin of the laminate is semi-cured resin with unbound photo-initiator and / or thermo-initiator, and preferably bonds with said sheets by said one more of said one or more functional endgroups.

[0114] This laminate can or cannot be made according to the sixth aspect and preferably is made according to the sixth aspect. The features and preferred embodiments of the sixth aspect of the invention therefore apply mutatis mutandis for the seventh aspect and vice versa.

[0115] Such a laminate is very suitable to cover up all types of surfaces.

[0116] The invention also relates to a glue or resin as such, wherein said glue is a glue as described in the first, second, third, fourth or fifth aspect of the invention or wherein the resin is a resin as described in the sixth or seventh aspect of the invention.

[0117] With the intention of better showing the characteristics of the invention, herein below, as an example without any limitative character, embodiments of the invention are described, with reference to the following schematic figures: -figure l is a schematic view of steps described in a method according to the first aspect or the fourth aspect of the invention to form board material, and of steps described in a method according to third aspect of the invention to form a decorative panel made with board material;

[0118] -figure 2 shows a cross section of a board material according to the second aspect of the invention, wherein said board material could be made by the method shown in figure 1 and further a decorative panel made with said board material;

[0119] -figure 3 is close-up of F3 shown in figure 2;

[0120] -figure 4 is an enlarged view of F4 of figure 1, and showing a step of a first embodiment of a method according the fourth aspect of the invention;

[0121] -figure 5 is an enlarged view of F5 of figure 1, and showing a step of a second embodiment of a method according the fourth aspect of the invention;

[0122] -figure 6 is a perspective view of a laminate according to the seventh aspect of the invention;

[0123] -figure 7 is a view which shows a possible use of the laminate shown in figure 6, wherein said laminate comprises a photo-initiator;

[0124] -figure 8 is an exploded view of cross section of laminate according to the seventh aspect of the invention.

[0125] According to a first possibility, figure 1 shows an embodiment of a method to form a decorative panel 7 according to the third aspect of the invention, and also shows an embodiment of a method according to the first aspect of the invention, to form a board material 1 that is used in said third aspect of the invention. According to a second possibility, figure 1 shows an embodiment of method to form a board material 1 according to the fourth aspect of the invention, wherein said board material 1 is further used to form a decorative panel 7. The difference for said two possibilities is the used glue or used glues to form said board material 1. Further for said second possibility, radiation can be applied at different places, which is shown in figures 4 and 5 which show enlargements of F4 and F5 of figure 1.

[0126] Said board material 1 comprises at least three layers, namely a central layer 1 A which is sandwiched between two outer layers IB. Said board material 1 is thus preferably a three- layered board material 1. Of course other embodiments (not shown) wherein the board material 1 is one layered, two layered, four layered, five layered, and so on, are also possible.

[0127] To form said board material 1 plant particles are provided. Said plant particles are preferably wood chips, wherein said wood chips can or cannot comprise recycled wood chips. If wood chips are used, the board material 1 can be indicated as a particle board material. Instead of using wood chips, use can be made of wood fibers, wherein said wood fibers can or cannot comprise recycled wood fibers. The board material 1 can then be indicated as a wood fiberboard material.

[0128] Said plant particles are then provided with a curable glue, for example by bringing both said plant particles and said curable glue in a mixing unit and / or a blowline, as such forming glued plant particles 2. Said glued plant particles 2 are preferably scattered upon a belt to form a cake 3. For example, as is shown in figure 1, if a three-layered cake 3 needs to be formed, to form a three-layered board material 1, three scatterers 13 can be used to each scatter a layer of glued plant particles 2. The glued plant particles 2 present in said different scatterers 13 can or cannot be the same. For example said glued plant particles 2 which are scattered by the scatterer 13 to form the central layer 1A of the board material 1, can have a different glue and / or a different type of plant particles and / or a different ratio glue:plant particles, then the glued plant particles 2 which are scattered by said scatterers 13 to form the outer layers IB of the board material 1. For example, the plant particles 2 of the central layer 1 A, if they are wood chips, can be more coarse, than the plant particles of the outer layers IB. For example the plant particles of the central layer 1 A can have a higher recycled content than the plant particles of the outer layers IB. For example the dry matter ratio glue:plant particles can be higher for the outer layers IB, for example the outer layers IB can have a dry matter ratio glue:plant particles between 8: 100 and 12: 100, while the central layer 1A can have a dry matter ratio glue:plant particles between 5:100 and 8:100. Said formed cake 3 is pressed, for example as shown in figure 1, firstly by a prepressing device 5 followed by a continuous double belt press 4. The belts of the continuous double belt press 4 are preferably heated.

[0129] For the first possibility of figure 1, thus for making a decorative panel 7 according to the third aspect of the invention, use is made of a board material 1 which is made according to the first aspect of the invention and which is also a board material 1 according to the second aspect of the invention. At least the glue used to form the outer layer IB upon which a decorative top layer will be provided to form said decorative panel 7, has the following features: the curable glue comprises one or more (meth)acrylates and / or unsaturated polyesters, and further comprises a thermo-initiator for activating unsaturated carbon-carbon bonds of said one or more (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 seconds half-life of a first temperature, said first temperature preferably being between 80 °C and 250 °C. Further said glue comprises one or more functional endgroups, wherein said one or more functional endgroups are preferably chosen from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes, or combinations thereof; wherein said one or more functional endgroups are part of said one or more (meth)acrylates and / or unsaturated polyesters and / or are part of one or more additional molecules of the curable glue.

[0130] In said first possibility the temperature of said cake 3 during pressing said cake 3 with the continuous double belt press 4, remains lower than said first temperature, preferably remains at least 10°C lower than said first temperature. Said one or more functional endgroups are activated during said pressing such that said functional endgroups form bounds with the plant particles and such that the board material l is a semi-cured board material. Here at least the outer layer IB of the board material 1 upon which a decorative top layer will be applied is semi-cured. Of course said other outer layer IB and / or said central layer 1A could also comprise a similar glue and be semi-cured. The importance of having one at least semi-cured outer layer IB is further explained with figures 2 and 3. The temperature of the belts of the continuous doublet belt press 4 are lower than said first temperature, preferably lower than 150°C, for example between 100 °C and 125 °C, such that the temperature of the cake 3 remains below the first temperature.

[0131] For the second possibility of figure 1, at least the glue used to form the central layer 1 A has the following features: the curable glue comprises (meth)acrylates and / or unsaturated polyesters, and further comprises a photo-initiator for activating unsaturated carboncarbon bonds of said (meth)acrylates and / or unsaturated polyesters. Before or during pressing said cake 3 with the prepressing device 5 and / or the continuous double belt press 4, said curable glue is exposed to radiation, such that curing of said glue is enhanced. For example as shown in figure 5, the glued plant particles 2 can be exposed to radiation during scattering by a scatterer 13, and this for example with the aid of an UV light emitting device 14. For example as shown in figure 4, radiation can be supplied by an electron beam device 15 to the cake 3, for example between the prepressing device 5 and the continuous double belt press 4. Of course radiation can be supplied by both said UV light emitting device 14 and said electron beam device 15. The result can be a board material 1 which is substantially fully cured when it leave the continuous double belt press 4.

[0132] Further, for both said possibilities, said board material 1 is used to form a decorative panel 7 by forming a stack in for example a single daylight press with two heated press plates 6, and then pressing said stack, for example at a temperature of between 180°C and 200 °C for between 15 and 60 seconds at a pressure of at least 5 bar. Said stack comprising from bottom to top

[0133] -a balancing layer 16, for example a resin impregnated kraft paper, said resin being a melamine-formaldehyde resin or an acrylate resin or an unsaturated polyester resin;

[0134] -a said board material 1;

[0135] -a resin impregnated printed paper 10, or a resin impregnated uniformly coloured paper, said resin being a melamine-formaldehyde resin or an acrylate resin or an unsaturated polyester resin, and wherein said resin impregnated printed paper 10 can or cannot be coated;

[0136] -a wear layer 12, for example formed by a resin impregnated translucent / transparent paper 12, said resin being a melamine-formaldehyde resin or an acrylate resin or an unsaturated polyester resin and / or comprising one or more acrylate coatings and / or comprising one or more unsaturated polyester coatings and / or comprising wear resistant particles such as aluminum oxide or corundum.

[0137] In the first possibility the thickness D2 of the board material 1 in the decorative panel 7 is smaller than the thickness DI of the board material 1 before forming said decorative panel 7. This is possible since the board material 1 is a semi-cured board material such that further densification is possible. For example the board material 1 can have an average density of 850 kg / m3before it is laminated, and the board material 1 can have an average density of 1100 kg / m3when it forms the substrate of the decorative panel 7.

[0138] For the second possibility, the thicknesses DI and D2 are preferably similar. No further or no significant densification resulting from lamination.

[0139] Figures 2 and 3 relate to such a decorative panel 7 made with a board material 1 according to above mentioned first possibility. Here the decorative panel 7 can have deep embossments, e.g. pores 8. In the embodiment shown in figure 3, the embossments extend into the board material 1, at least into the corresponding outer layer IB, but preferably also into the central layer 1A, of the board material 1. For this use can be made of press plates 6 having a structured surface with protrusions which contacts the wear layer 12 during pressing of said stack. The structure of said surface can be very well copied when making use of said board material 1 and this without risking pressing defects.

[0140] Figures 6, 7 and 8 relate to the sixth and seventh aspect of the invention. Figures 6 and 8 show a flexible laminate 9. As can be seen in figure 8, said laminate 9 is made from a stack comprises from bottom to top:

[0141] -three resin impregnated kraft papers 11, impregnated with a first resin;

[0142] -a resin impregnated printed paper 10, or a resin impregnated uniformly coloured paper, said resin being a melamine-formaldehyde resin or an acrylate resin or an unsaturated polyester resin. Said resin impregnated paper 10 can optionally be coated with for example an acrylate coating or an unsaturated polyester coating; -a wear layer 12, for example formed by a resin impregnated translucent / transparent paper 12, said resin being a melamine-formaldehyde resin or an acrylate resin or an unsaturated polyester resin and / or comprising one or more acrylate coatings and / or comprising one or more unsaturated polyester coatings and / or comprising wear resistant particles such as aluminum oxide or corundum.

[0143] The first resin comprises (meth)acrylates and / or unsaturated polyesters, and wherein said first resin further comprise functional endgroups, wherein said functional endgroups are preferably chosen from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes, or combinations thereof; wherein said functional endgroups are part of said (meth)acrylates and / or unsaturated polyesters and / or are part of additional molecules of the first resin, wherein said functional endgroups are activated during said lamination step and wherein the first resin further comprises:

[0144] -a photo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters; and / or

[0145] -a thermo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 second half-life of a first temperature, said first temperature preferably being between 80 °C and 250 °C.

[0146] Preferably said laminate 9 is made up of said above-mentioned sheets which are laminated together with said above-mentioned resins. The laminate 9 is thus formed by a lamination step wherein a stack of said sheets is formed and pressed together to laminate said sheets together. If the first resin comprises said thermo-initiator the maximum temperature of said stack during said lamination remains lower than said first temperature.

[0147] Said laminate 9 is thus a semi -cured laminate since the first resin is not fully cured after said lamination step and can thus have a certain flexibility. The benefit here is that said laminate 9 can be easily form fittingly applied upon a surface, for example the surface of beam shaped object 17 as shown in figure 7. First said laminate 9 is applied upon the surface of said object 17 to form a wrapped object and then said laminate 9 is further cured to form a covered object 18. The result is a laminate 9 which closely follows the shape of object 17, as such forming an aesthetic covered object 18. If said glue comprises said photo-initiator, said wrapped object can be exposed to radiation for example by bringing said wrapped object in a room in which a device 15 which emits electron beams is present. If said glue comprises said thermo-initiator, said wrapped object can be placed in an oven such that a temperature above said first temperature is obtained.

[0148] The present invention is not limited to the preferred embodiments described above, but such board materials, panels and methods may be realized according to several variants without leaving the scope of the invention.

Claims

Claims1 A method for producing a board material (1), said board material (1) comprising plant particles, for example lignocellulose particles such as fibers or chips, wherein said method comprises at least the following steps:- a step of providing plant particles;- a step of providing a curable glue to said plant particles to form glued plant particles (2);-a step of forming a cake (3) comprising said glued plant particles (2);-a step of pressing said cake (3) to form said board material (1), characterized in that the curable glue comprises one or more (meth)acrylates and / or unsaturated polyesters, and further comprises a thermo-initiator for activating unsaturated carbon-carbon bonds of said one or more (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 seconds half-life of a first temperature, said first temperature preferably being between 80 °C and 250 °C, wherein the temperature of said cake (3) during said step of pressing said cake (3), remains lower than said first temperature, and wherein said curable glue further comprises one or more functional endgroups, wherein said one or more functional endgroups are preferably chosen from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes and siloxanes, or combinations thereof; wherein said one or more functional endgroups are part of said one or more (meth)acrylates and / or unsaturated polyesters and / or are part of one or more additional molecules of the curable glue, wherein said one or more functional endgroups are activated during said step of pressing said cake (3), such that the board material (1) is a semi-cured board material.2.- The method according to claim 1, wherein the temperature of said cake (3) during said step of pressing said cake (3), remains at least 10°C lower than said first temperature.3.- The method according to claim 1 or 2, wherein the thermo-initiator is a peroxide.4.- The method according to any of the preceding claims, wherein the curable glue comprises one or more (meth)acrylates, and wherein said one or more (meth)acrylates comprise said one or more functional endgroups, for example comprises one or more isocyanate endgroups.5.- The method according to any of the preceding claims, wherein the curable glue comprises one or more (meth)acrylates and said one or more (meth)acrylates have at least an acrylate functionality of two.6.- The method according to any of the preceding claims, wherein the glue comprises said one or more additional molecules, wherein said one or more additional molecules are preferably selected from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes, and mixtures thereof.7.- The method according to any of the preceding claims, wherein the glue comprises one or more (meth)acrylates, wherein said one or more (meth)acrylates comprise, and preferably consist of, oligomers selected from the group consisting of polyester acrylates, polyester methacrylates, and mixtures thereof, preferably wherein said oligomers have a molar mass equal to or higher than 800 g / mol and lower than 7000 g / mol.8.- The method according to any of the preceding claims, wherein the step of pressing said cake (3) comprises heat pressing said cake (3) at a temperature of at most 150 °C, preferably at a temperature of between 80 °C and 130°C, for example between 90 °C and 100 °C.9.- The method according to any preceding claims, wherein a continuous double belt press (4) is used for said step of pressing, wherein the maximum temperature of the belts of the continuous double belt press (4) is at most 150 °C and / or wherein the pressure applied by said continuous double belt press (4) is between 20 and 150 bar.10.- A board material comprising plant particles, for example lignocellulosic particles, wherein said plant particles have been pressed and bonded together with a curable glue, wherein said curable glue comprises one or more (meth)acrylates and / or unsaturated polyesters, and further comprises a thermo-initiator for activating unsaturated carboncarbon bonds of said one or more (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 seconds half-life of a first temperature, said first temperature preferably being between 80 °C and 250 °C, and wherein said curable glue further comprises one or more functional endgroups, wherein said one or more functional endgroups are preferably chosen from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes, or combinations thereof; wherein said one or more functional endgroups are part of said one or more (meth)acrylates and / or unsaturated polyesters and / or are part of one or more additional molecules of the curable glue.11.- The board material of claim 10, wherein said board material (1) is a semi-cured board material with unbound thermo-initiator and preferably bonds between one more of said one or more functional endgroups and plant particles.12.- The board material according to claim 11, wherein said board material (1) is obtained by a method according to any of the preceding claims 1 to 9.13.- The board material according to any of the claims 10 to 12, wherein the average density of the board material (1) is between 500 and 900 kg / m3.14.- A method for producing a decorative panel, wherein at least a decorative top layer is laminated to a surface of a board material (1) by heat pressing, characterized in that a board material (1) according to any of claims 10 to 13 and / or produced according to a method according to any of the preceding claims 1 to 9, is provided and wherein said board material (1) during said heat pressing, at least at the height of said surface, reaches a temperature which is higher than the first temperature, such as to activate said thermoinitiator and to further cure the board material (1).15.- A method according to claim 14, wherein for said heat pressing, said board material(1) and said decorative top layer are placed on top of each other and pressed between press elements (6), wherein at least said press element (6) which contacts said decorative top layer comprises protrusions to provide the decorative top layer with a relief, wherein at least one protrusion has a minimum height of at least 1 mm.16.- A decorative panel, wherein said decorative panel (7) is manufactured according to claim 15 and wherein said decorative panels (7) comprises one or more pores (8) with a minimum height of at least 1 mm, wherein said pores (8) preferably extend into the board material (1).17.- A method for producing a board material, said board material (1) comprising plant particles, for example lignocellulosic particles such as fibers or chips, wherein said method comprises at least the following steps:- a step of providing plant particles;- a step of providing a curable glue to said plant particles to form glued plant particles(2);- a step of forming a cake (3) comprising said glued plant particles (2);- a step of pressing said cake (3) to form said board material (1), characterized in that the curable glue comprises (meth)acrylates and / or unsaturated polyesters, and further comprises a photo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters, wherein before or during the step of pressing said cake (3), said curable glue is exposed to radiation, such as to enhance curing of said glue.18.- The method as in claim 17, wherein the curable glue further comprises a thermoinitiator, wherein said thermo-initiator has a 60 seconds half-life of a first temperature, said first temperature preferably being between 50 °C and 250 °C, wherein said step of pressing said cake (3) comprises heat pressing said cake (3), and wherein the maximum temperature of said cake (3) during said step of heat pressing said cake (3) is higher than said first temperature.19.- The method according to claim 17 or 18, wherein said curable glue further comprises functional endgroups, wherein said functional endgroups are part of said (meth)acrylates and / or unsaturated polyesters and / or are part of additional molecules of the glue and wherein preferably said functional endgroups are chosen from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes, or combinations thereof.20.- The method according to any of the preceding claims 17 to 19, wherein the curable glue comprises one or more (meth)acrylates, wherein said one or more (meth)acrylates comprise oligomers selected from the group consisting of polyester acrylates, polyester methacrylates, or mixtures thereof, preferably wherein said oligomers have a molar mass equal to or higher than 800 g / mol and lower than 7000 g / mol.21.- The method according to any of the preceding claims 17 to 20, wherein the curable glue comprises one or more (meth)acrylates, wherein said one or more (meth)acrylates comprise acrylate reactive diluents, wherein said acrylate reactive diluents have a molar mass lower than 900 g / mol, and preferably lower than 500 g / mol .22.- A board material, wherein said board material (1) is obtained by a method according to any of the preceding claims 17 to 21.23.- A method for manufacturing a laminate, said laminate (9) comprising two or more sheets and one or more resins, wherein at least one of said one or more resins is a first resin, wherein the method comprises a lamination step wherein a stack of two or more sheets is formed and pressed together to laminate said sheets together, wherein said two or more sheets in said stack are impregnated and / or coated with said one or more resins and / or wherein said one or more resins in said stack are provided between two consecutive sheets of said two or more sheets, characterized in that the first resin comprises (meth)acrylates and / or unsaturated polyesters, and wherein said first resin further comprise functional endgroups, wherein said functional endgroups are preferably chosen from the list of: isocyanates, epoxides, amines such as primary amines, aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes, or combinationsthereof; wherein said functional endgroups are part of said (meth)acrylates and / or unsaturated polyesters and / or are part of additional molecules of the first resin, wherein said functional endgroups are activated during said lamination step and wherein the first resin further comprises:-a photo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters; and / or-a thermo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 second half-life of a first temperature, said first temperature preferably being between 80 °C and 250 °C, wherein the maximum temperature of said stack during said lamination step remains lower than said first temperature.24.- The method according to claim 23, wherein the laminate (9) is a decorative laminate comprising at least one decorative sheet (10) and at least one structural sheet (11), wherein in said stack, said structural sheet (11) is at least impregnated and / or coated with said first resin.25.- The method according to claim 23 or 24, wherein the laminate (9) comprises a decorative top layer comprising at least said one decorative sheet (10) and a structural layer comprising at least said one structural sheet (11), wherein said decorative top layer comprises a second resin different from said first resin, preferably wherein the second resin comprises (meth)acrylates and / or unsaturated polyesters and a thermo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 seconds half-life of a second temperature, wherein the maximum temperature of said stack during said lamination step is higher than said second temperature.26.- A laminate being made up of at least two sheets which are laminated together with one or more resins, wherein at least one of said one or more resins is a first resin, wherein the first resin comprises (meth)acrylates and / or unsaturated polyesters, and wherein said first resin further comprise functional endgroups, wherein said functional endgroups are preferably chosen from the list of: isocyanates, epoxides, amines such as primary amines,aziridines, carbodiimides, polyalcohols, hydroxyl groups, silanes, siloxanes, or combinations thereof; wherein said functional endgroups are part of said (meth)acrylates and / or unsaturated polyesters and / or are part of additional molecules of the first resin, wherein the first resin further comprises: -a photo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters.; and / or-a thermo-initiator for activating unsaturated carbon-carbon bonds of said (meth)acrylates and / or unsaturated polyesters, wherein said thermo-initiator has a 60 second half-life of a first temperature, said first temperature preferably being between 80 °C and 250 °C; wherein said first resin of the laminate (9) is a semi-cured resin with unbound photoinitiator and / or thermo-initiator, and preferably bonds with said sheets by said one or more functional endgroups. 27.- The laminate according to claim 26, wherein the laminate (9) is a laminate manufactured according to any of the preceding claims 23 to 25.

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