Lignocellulosic composite material and method for manufacturing thereof

Abstract

The present invention relates to a composition comprising cellulose, hemicellulose, and lignin, wherein one or more of the cellulose, hemicellulose, lignin are acetylated. It further relates to a wood composite material comprising said composition. It also relates to a method for producing same said composition comprising the steps of: - mixing lignocellulosic biomass in the range of 70 dry wt.% to 95 dry wt.% with lignin in the range of 5 dry wt.% to 30 dry wt.% providing a mixture; - hot-pressing the resulting mixture at a temperature in the range of 100 °C to 220 °C and a pressure in the range of 1 MPa to 20 MPa, for a time in the range of 10 seconds to 300 seconds per millimeter pressed mixture; and - curing the mixture.

Description

[0001] LIGNOCELLULOSIC COMPOSITE MATERIAL AND METHOD FOR MANUFACTURING THEREOF

[0002] The present invention relates to a composition comprising a lignocellulosic biomass, a composite wood material such as a plate or sheet material comprising said composition, a circular composite wood material comprising said composition, and method for manufacturing said composition. Wood is a well-known and widely used material for building structures. Depending on the tree source and on the methods used to treat wood, it can have many different characteristics relating to its structural integrity and resistance to erosion and wear. These are further determined by the natural structure of wood; as an organic tissue material, its structural integrity is mostly derived from the cellulosic fibers forming the cell walls and space between them. These fibers mostly comprise cellulose, an organic polysaccharide polymer consisting of linearly linked glucose molecules. They also comprise hemicellulose and pectin, which are both associated organic polysaccharide that are comprised of a more diverse set of sugar monomers and may be bound to the cellulose strands. Finally, the fibers comprise lignin, a further complex and heterogeneous organic polymer comprised of so-called lignols. While cellulose, hemicellulose and pectin mostly form the cell walls of plant cells, lignin occupies the space between these cell walls providing further structural integrity to the plant and wood tissue. Biomass such as wood, comprising a high amount of these polymers is often referred to as lignocellulosic biomass.

[0003] Because wood is a highly heterogeneous material due to its organic nature, it is often processed into more homogeneous materials. One widely used method for doing so is the production of composite wood. Such materials are generally manufactured from a mix of wood fibers with additional materials that have different structural properties, resulting in a composite material that combines the properties of the blended materials. Often-used wood fibers include chipped or shredded wood to provide relatively uniform and homogeneous wood fibers. These are then processed into so-called engineered or composite wood materials, in which the wood fibers are bound together with adhesives or other methods of fixation.

[0004] However, common manufacturing processes of these materials involve the use of harsh chemical adhesives, such as formaldehyde-based resins, phenol, melamine and isocyanates. These harmful compounds are hazardous both to the health of employees working in the manufacturing process, and to the environment. In addition, the use of these adhesives means that at the end of their lifecycle, these materials cannot be easily reused; the composition comprises harmful components that are not tolerable in the recycling process and requires further chemical adhesives upon reuse, rendering them difficult to recycle in a sustainable manner. In addition, these composite wood materials, and structures and furniture manufactured from them, slowly exude the chemical adhesives over their lifetime. This has negative implications for the health of people living and / orworking in close proximity to these structures and furniture. As such, there exists a need for more healthy and sustainable composite wood materials and methods for manufacturing them. Preferably, such desired compositions do not comprise harmful chemical adhesives at all. As a more sustainable alternative, the use of other adhesives such as plant lignin, the natural adhesive in wood, may be explored.

[0005] However, conventional composite wood materials comprising lignin adhesives have poor water resistance and absorb water upon contact, in addition to having mediocre structural properties. These problems prevent an efficient and effective use of biomass for composite wood material and the like. These problems are even bigger considering the scale on which such materials are used. It is an object of the invention to provide a sustainable alternative composite wood material that has good structural properties without the harmful side-effects to manufacturing personnel, users of products manufactured from the materials, and the environment. It is a further object of the invention to provide a method for manufacturing such materials.

[0006] This objective is achieved with a composition comprising cellulose, hemicellulose, and lignin, wherein one or more of the cellulose, hemicellulose, lignin are acetylated.

[0007] It is noted that acetylation is an organic esterification reaction between a substrate and acetic anhydride, which ultimately introduces an acetyl group in the substrate. Cellulose, hemicellulose, and lignin contain many hydroxyl-groups which contribute to the hydrophilicity of the fibers. These can be acetylated with an appropriate agent (such as acetic anhydride), resulting in the substitution of the hydroxyl-group by an acetyl-group.

[0008] An advantage of acetylating one or more of the cellulose, hemicellulose, and lignin is that the abundance of charged groups and / or sidechains is reduced compared to cellulose, hemicellulose, and lignin which is not acetylated. As a result, the hydrophilicity of the composition according to the invention is lower and / or the hydrophobicity of the composition according to the invention is higher compared to conventional compositions. Therefore, the composition according to the invention has an increased water resistance compared to conventional compositions and / or composite materials. The acetylation of the exterior of the composite wood material comprising the composition results in a low permeability to water, while the acetylation of the interior of the material means that water that does enter has less interaction with the glued fibers, leading to the material retaining structural integrity under the influence of water even when water enters the material.

[0009] Accordingly, it was found that the composition according to the invention tends to swell less or even does not swell compared to conventional compositions / composite wood materials. It is noted that swelling and warping of said material is highly detrimental to the structural integrity and dimensional stability of buildings or furniture comprising the material. Therefore, the composition according to the invention is enabled to be used in exterior materials and interior materials, especially under damp, moist, wet and even submerged conditions. It is noted that exterior materials refer tomaterials which are outside a climatized space such as being outside, and interior materials refer to materials which are inside.

[0010] A further advantage of the composition according to the invention using lignin, is that said lignin acts as an adhesive and / or forms a matrix within the composition. Said lignin enables to cross-link with other components within the composition. As a result, the composition according to the invention may have adhesive properties, wherein the amount of lignin improves the adhesion within the composition according to the invention. Therefore, less or no environmentally unfriendly additives such as adhesive promotors or adhesives need to be used in the composition according to the invention.

[0011] It is noted that raw lignin may be obtained as a byproduct of industrial processes in certain industries, such as the paper industry. Such raw lignin retains its binding properties and so is suitable for addition to wood fibres to provide adhesion of the fibres to each other. It is furthermore completely natural, and some endogenous lignin is already part of the lignocellulosic biomass. Material glued with raw lignin as adhesive can be reused several times and is therefore far more sustainable than conventional composite wood products glued with chemical adhesives available while matching or surpassing their structural properties. Because lignin is a heterogeneous polymer, using lignins with different structure, molecular mass and length may result in different degrees of adhesion; in addition, one can purposefully use lignin with different properties than the lignin in the lignocellulosic biomass to be treated so as to obtain composite wood materials with unique properties.

[0012] Thus, the composition according to the invention is a composition with an improved water resistance which can be used in exterior, underground, or submerged applications, which is sustainable and circular, and which has excellent mechanical properties.

[0013] This objective is achieved through the acetylation of the lignocellulosic biomass, specific components of said biomass, the raw lignin used as adhesive, or several of these.

[0014] In a presently preferred embodiment according to the invention, the cellulose in the lignocellulosic biomass may be acetylated. The lignocellulosic biomass may be treated with additional methods that enhance its sustainability and / or durability, such as for example platonisation.

[0015] It was found that acetylating the cellulose improves the water and moist resistance significantly compared to conventional compositions. For example, a (cured) composition according to invention comprising acetylated cellulose has a moist / water uptake of at most 10%, more preferably at most 5%, even more preferably lower than 3%.

[0016] In further presently preferred embodiment according to the invention, the lignin may be acetylated. Alternatively, or in addition to the acetylated lignin, the hemicellulose may be acetylated.An advantage of acetylating the lignin is that the permeability for moist / moisture of the (cured) composition according to the invention is reduced and that the adhesive capability of the lignin is not affected. In addition, the interior of the composite material of comprising the composition is also less reactive with water and therefore retains its structural properties in moist or even submerged conditions.

[0017] In a preferred embodiment, cellulose and hemicellulose are aceylated.

[0018] In a further presently preferred embodiment, the cellulose, hemicellulose, and lignin are acetylated.

[0019] It was found that acetylating the cellulose, hemicellulose, and lignin provides a (cured) composition according to the invention provides the desired water / moist / moisture resistance and strength.

[0020] Thus, an advantage of acetylating the cellulose, hemicellulose, and lignin of the (cured) composition according to the invention is an increase of hydrophobicity, which makes the composition more water-resistant and therefore more durable and usable in both interior and exterior applications.

[0021] In a further presently preferred embodiment according to the invention, 5 dry wt.% to 90 dry wt.% of the one or more of the cellulose, hemicellulose, lignin may be acetylated, preferably 15 dry wt.% to 90 dry wt.%.

[0022] It is noted that the weight percentages are defined based on the dry weight of the composition according to the invention.

[0023] It is also noted that acetylated cellulose, acetylated hemicellulose, and acetylated lignin refer to a cellulose, hemicellulose, or lignin which, in order of increased preference, have at least 25 %, 30 %, 35%, 40%, 45%, or 50% of the hydroxy groups acetylated respectively.

[0024] In a further presently preferred embodiment according to the invention, the acetylated cellulose, hemicellulose, and / or lignin have an increased molecular weight of at least 2%, preferably at least 10%, more preferably at least 20%, most preferably at least 40%, compared to the untreated / raw cellulose, hemicellulose, and / or lignin.

[0025] In a further presently preferred embodiment according to the invention, the cellulose may be present in an amount in the range of 30 dry wt.% to 70 dry wt.%, preferably present in an amount in the range of 40 dry wt.% to 60 dry wt.%, more preferably present in an amount in the range of 45 dry wt.% to 55 dry wt.%.

[0026] In a further presently preferred embodiment according to the invention, the cellulose may be present in an amount in the range of 10 dry wt.% to 70 dry wt.%, preferably present in an amount in the range of 40 dry wt.% to 60 dry wt.%, more preferably present in an amount in the range of 45 dry wt.% to 55 dry wt.%.In a further presently preferred embodiment according to the invention, the hemicellulose may be present in an amount in the range of 10 dry wt.% to 30 dry wt.%, preferably present in an amount in the range of 10 dry wt.% to 25 dry wt.%, more preferably present in an amount in the range of 10 dry wt.% to 20 dry wt.%.

[0027] In a further presently preferred embodiment according to the invention, the lignin may be present in an amount in the range of 5 dry wt.% to 80 dry wt.%, preferably present in an amount in the range of 15 dry wt.% to 70 dry wt.%, more preferably present in an amount in the range of 35 dry wt.% to 65 dry wt.%.

[0028] In a preferred embodiment according to the invention, the cellulose may be present in an amount in the range of 30 dry wt.% to 70 dry wt.%, preferably present in an amount in the range of 40 dry wt.% to 60 dry wt.%, more preferably present in an amount in the range of 45 dry wt.% to 55 dry wt.%, the hemicellulose may be present in an amount in the range of 10 dry wt.% to 30 dry wt.%, preferably present in an amount in the range of 10 dry wt.% to 25 dry wt.%, more preferably present in an amount in the range of 10 dry wt.% to 20 dry wt.%, the lignin may be present in an amount in the range of 5 dry wt.% to 50 dry wt.%, preferably present in an amount in the range of 5 dry wt.% to 40 dry wt.%, more preferably present in an amount in the range of 5 dry wt.% to 35 dry wt.%. It is noted that the aforementioned amounts present in the composition according to the invention may refer to cellulose or acetylated cellulose, hemicellulose or acetylated cellulose, lignin or acetylated lignin respectively.

[0029] In a further presently preferred embodiment according to the invention, the lignin comprises exogenous lignin. Preferably, wherein the exogenous lignin may be one or more selected from the group of soda lignin, Kraft lignin, and lignins produced through sulphite processing and neutral sulphite semichemical processing.

[0030] It is noted that the exogenous lignin may also be referred to as technical lignin.

[0031] It is noted that soda lignin refers to lignin produced through soda pulping, a well-known chemical process used in the milling industry for producing lignin. Likewise, Kraft lignin refers to lignins produced through the Kraft pulping process. The pulping process determines the chemical makeup of the produced lignin. While the Soda process makes use of alkali compounds, usually sodium hydroxide to dissolve lignin, the Kraft process as well as the sulphite processes additionally make use of sulfurous alkalic compounds. The use of sulfurous compounds improves recovery of lignin after treatment, but decreases the purity and amount of free monomers in the recovered lignin, with more free monomers and less impurities equating to a better binding potential of the lignin to the substrate.

[0032] Furthermore, soda lignin, Kraft lignin, and lignins produced through sulphite processing and neutral sulphite semichemical processing are different compared to native lignin. Native lignin refers to the biopolymer as it naturally exists within plant cell walls. Soda lignin refers to a byproduct froma soda pulping process, Kraft lignin refers to an industrial lignin derived from Kraft pulp, and lignins produced through sulphite processing refers to lignosulfonates or sulfonated lignins. Said lignins produced through sulphite processing are water-soluble, sulphur-containing technical lignins, which are produced by treating wood chips with sulphite or bisulphite salts at temperatures in the range of 120 °C to 180 °C in an acidic environment (for example pH in the range of 1 to 5).

[0033] In a further presently preferred embodiment, the lignin comprises isolated lignin and / or modified lignin, for example chemically modified lignin.

[0034] It is noted that technical lignin includes isolated lignin and / or modified lignin.

[0035] In a further presently preferred embodiment, the composition according to the invention comprises native lignin and added lignin. Preferably, the native lignin is present in a lignocellulosic biomass.

[0036] The added lignin is preferably technical lignin / exogenous lignin, thus (chemically) modified lignin. Furthermore, in this application exogenous lignin also refers to technical lignin and vice versa. It was found that soda lignin has excellent adhesive properties which result in a composition (after curing) with good structural and dimensional stability. Because Soda lignin is produced without sulfurous compounds it comprises fewer contaminants, improving its adhesive properties and making it especially suitable for use as adhesive in high quality manufactured wood products. An advantage of the exogenous lignin is that said lignin is able to bind and can suitably bind to the other components within the composition and to itself according to the invention. As a result, additional structural integrity is achieved.

[0037] Furthermore, lignin of varying monomer composition and polymer length and from various sources may be used. As a result, the lignin may comprise different types of lignin. For example, more than one structurally different lignin may be present in the composition according to the invention.

[0038] In a preferred embodiment, the lignin is selected such that the binding properties are improved and thus the composition according to the invention provides desirable structural properties to the composition. This improves the suitability of the composition for use in both interior and exterior applications and eliminates or reduces the need for undesirable chemical adhesives that are harmful to operators, consumers, and the environment. In a further preferred embodiment, the composition of the invention comprises no chemical or synthesized adhesives at all. In a yet further preferred embodiment, lignin is the only adhesive in the composition of the invention.

[0039] In a further presently preferred embodiment according to the invention, the exogenous lignin may be acetylated. Preferably, the molecular weight of the exogenous lignin is increased with 10% to 80% after acetylation. In other words, the molecular weight of the exogenous lignin increases after acetylation.In a further presently preferred embodiment according to the invention, the cellulose, hemicellulose, and lignin are provided in the form of lignocellulosic biomass.

[0040] It is noted that the lignin present in the lignocellulosic biomass comprises native lignin.

[0041] An advantage of the lignocellulosic biomass is that said biomass is readily available in the industry. As a result, biomass is relatively cheap compared to other sources of cellulose, hemicellulose, and lignin. In addition, such lignocellulosic biomass already comprises a mix of these components in advantageous proportions. Typically, lignocellulosic biomass comprises 40 dry wt.% to 50 dry wt.% cellulose, 15 dry wt.% to 30 dry wt.% hemicellulose and 5 dry wt.% to 30 dry wt.% lignin. Therefore, lignocellulosic biomass is especially suitable as source of the components in the composition according to the invention.

[0042] In a further presently preferred embodiment according to the invention, the lignocellulosic biomass may be selected from the group of wood fibres, paper fibres, and / or other plant fibers. Preferably, the lignocellulosic biomass originates from wood and crops based fibres and / or paper fibres.

[0043] Such fibers can be obtained, for example, as by- or waste products of sawmills, the wood industry and the paper industry and are thus ubiquitously and cheaply available. They can also be obtained from agriculture and horticulture.

[0044] An advantage of the lignocellulosic biomass selected from the group of wood fibers, paper fibers, and crop based fibres such as hemp, miscanthus, sorghum, straw, or other crops is that said fibers have a uniform shape. As a result, the rigidity of the (cured) composition according to the invention is increased.

[0045] In a preferred embodiment, the composition according to the invention comprises lignocellulosic biomass in the range of 70 dry wt.% to 90 dry wt.%, and exogenous lignin in the range of 5 dry wt.% to 30 dry wt.%. Preferably, the composition according to the invention comprises lignocellulosic biomass in the range of 70 dry wt.% to 90 dry wt.%, and exogenous lignin in the range of 10 dry wt.% to 30 dry wt.%.

[0046] It was found that such a composition enables good application in construction and furniture through its excellent mechanical properties, such as bending strength, modulus of elasticity, and compressive strength. Furthermore, said composition does not produce and / or include harmful compounds. Therefore, the composition according to the invention is harmless to process. By varying the amount of exogenous lignin used, the properties of the resulting material can also be changed. As such, the amount of exogenous lignin is suitably selected to match the specific application of the desired composition and material.

[0047] It is noted that the total weight of the composition according to the invention (comprising cellulose, hemicellulose, and lignin) does not exceed 100 wt.%. In other words, the amount of the individual components (cellulose, hemicellulose, lignin) does affect the other components.The invention also relates to a composite wood material comprising the composition according to the invention. Such a composite wood material may be provided in the form of a plate or sheet material but may also have other shapes.

[0048] The composite wood material according to the invention provides the same or similar effects and advantages as those described for the composition according to the invention.

[0049] In addition, such composite wood material has excellent structural properties and water resistance and is suitable for interior and exterior use, while being fully sustainable and circular and completely safe to work with. Unlike composite wood material glued with chemical adhesives, it does not release harmful gases or compounds over its lifetime.

[0050] It is noted that circular refers to a circular product which promotes sustainable resources by minimizing waste, reusing materials, and creating closed-loop systems for continuous resource circulation. Thus, circularity as used herein refers to the material being recyclable and reusable over several product lifetimes.

[0051] In a presently preferred embodiment according to the invention, the composite wood material has, in order of increased preference, a moist percentage of at most 10 wt.%, at most 9 wt.%, at most 8 wt.%, at most 7 wt.%, at most 6 wt.%, at most 5 wt.%, of at most 4 wt.%, of at most 3 wt.%, and most preferably of at most 2 wt.%.

[0052] The low moist percentage results in a composite wood material that does not significantly warp over time and under conditions of differing humidity, thus providing a more reliable and stable building material.

[0053] A further advantage of the composition according to the invention is that wood rot is reduced or even prevented. Furthermore, the composition according to the invention also reduces or event prevents that insects are nesting in the composition according to the invention. For example, plate material made of the composition according to the invention used outside comprises less insects per square meter compared to conventional wood panels.

[0054] Yet another advantage of the composition according to the invention is that said composition is substantially moist resistant. As a result, expansion of the composition according to the invention is reduced or even prevented.

[0055] In a further presently preferred embodiment according to the invention, the composite wood material has a maximum moist absorption of at most 5 wt.% when exposed to water for 24 hours at room temperature.

[0056] An advantage is that the composite wood material according to the invention is particularly suitable for applications in which it comes into contact with water or high humidity.

[0057] The invention also relates to a circular composite wood material obtainable by the shredding and subsequently re-glueing of composite wood material according to the invention.The circular composite wood material according to the invention provides the same or similar effects and advantages as those described for the composition according to the invention, and the composite wood material according to the invention.

[0058] In a preferred embodiment, the shredded plate material is re-glued with additional lignin. Alternatively, the shredded material may be re-glued without additional lignin.

[0059] In practice, composite wood material according to the invention may be shredded and glued again using the same or a different lignin, resulting in new composite wood material that can be reused for a new purpose. Composite wood material according to the invention may be used up to 6 or 7 times before its structural properties are significantly adversely affected, making the material highly sustainable and ecologically friendly.

[0060] The invention also relates to a method for manufacturing a composition according to the invention, comprising the steps of:

[0061] mixing lignocellulosic biomass in the range of 70 dry wt.% to 95 dry wt.% with lignin in the range of 5 dry wt.% to 30 dry wt.% providing a mixture;

[0062] hot-pressing the resulting mixture at a temperature in the range of 100 °C to 220 °C and a pressure in the range of 1 MPa to 20 MPa, for a time in the range of 10 seconds to 300 seconds per millimeter pressed mixture with regard to thickness; and

[0063] curing the mixture, preferably until it has reached room temperature.

[0064] The method for manufacturing a composition according to the invention provides the same or similar effects and advantages as those described for the composition according to the invention, the composite wood material according to the invention, and circular composite wood material according to the invention.

[0065] In a presently preferred embodiment according to the invention, the step of mixing mixes lignocellulosic biomass in the range of 70 dry wt.% to 95 dry wt.% with lignin in the range of 5 dry wt.% to 30 dry wt.% providing a mixture, wherein the lignocellulosic biomass comprises cellulose, hemicellulose, and wherein one or more of the cellulose, hemicellulose, lignin are acetylated.

[0066] It is noted that the step of hot-pressing the resulting mixture and the step of curing the mixture may be performed at the same time. In addition, the step of curing may be performed during and after the step of hot-pressing.

[0067] In a preferred embodiment, the method further comprises the step of providing the lignocellulosic biomass to a reactor and / or the step of providing the lignin to the reactor, wherein the step of mixing is performed in the reactor.

[0068] In a further preferred embodiment, the acetylation of the cellulose, hemicellulose, and / or lignin may be performed by adding an acetylating agent to the cellulose, hemicellulose, or lignin.

[0069] The degree of acetylation of the substrate may be varied through, for example, the use of more or less concentrated acetylation agents, or through longer or shorter treatment time. The temperatureand / or pressure at which the acetylation is performed may also be varied. Preferably, the acetylation is performed through the treatment of the substrate with acetic acid anhydride. It is also possible to subject the different components to different degrees of acetylation, or to use different acetylation methods for the different components.

[0070] The step of hot-pressing may be performed with generic hot-presses available, and can be performed with or without a mold.

[0071] In addition, the method is suitable for use in a continuous process, and can therefore be used to make composite wood materials of varying dimensions and / or shapes. This process has the advantage of being both dry and relatively fast.

[0072] A further advantage of the composition according to the invention and method according to the invention is that the composition according to the invention is substantially free of solvent (for example water) and the method according to the invention for manufacturing the composition according to the invention is free of solvent (for example water), although solvents may be added when desired

[0073] As a result, the method according to the invention uses less energy as no solvent needs to be extracted from the composition according to the invention.

[0074] Therefore, this makes the method easier to work with and produces fewer side-products. Because the method does not use any chemical adhesives and exclusively uses bio-based and bio-degradable components, it is completely safe for operators. The selected lignin may be of a comparable molecular weight and structure as the lignin present in the lignocellulosic biomass but may also have different properties.

[0075] In a presently preferred embodiment according to the invention, a lignin with a different structure and / or molecular weight than the lignin that is present in the lignocellulosic biomass is used.

[0076] An advantage of varying the lignin, the operator can change the characteristics of the material produced, such as its structural properties like stiffness and elasticity. These properties are affected by the amount of cross-linking between the fibers and the adhesive.

[0077] In a further presently preferred embodiment according to the invention, the method further comprises the step of acetylating the lignocellulosic biomass, preferably wherein the step of acetylating the lignocellulosic biomass is performed before the step of mixing.

[0078] This acetylation step may be performed in various ways including, but not limited thereto, the addition of an acetylating agent. The lignocellulosic biomass may furthermore be treated with other treatments to increase sustainability and durability, such as for example platonisation.

[0079] It is noted that the degree of acetylation may be changed by, for example, increasing or decreasing the duration of the acetylation step or by using a different agent.

[0080] The use of acetylated lignocellulosic biomass improves the hydrophobicity of the material, resulting in an improved water resistance of the produced composite material.In a further presently preferred embodiment according to the invention, the method further comprises the step of acetylating the lignin, preferably wherein the step of acetylating the lignin is performed before the step of mixing.

[0081] Acetylating the exogeneous lignin further improves the hydrophobicity of the produced composition and its water resistance, but may also influence the binding and cross-linking of the exogenous lignin to the lignocellulosic biomass. The degree of acetylation and amount of acetylated material used may therefore be suitably changed to alter the structural and other properties of the produced material. It is possible to use different degrees of acetylation for the lignocellulosic biomass and for the exogenously added lignin.

[0082] In a further present preferred embodiment according to the invention, the step of acetylating the lignocellulosic biomass and / or the step of acetylating the lignin is performed after the step of curing. Acetylating after the step of curing will result in different degree of acetylation; because the material is already pressed, the outside of the material will be more strongly acetylated than the inside. This allows the operator to acetylate the material in a heterogeneous way, expanding the practical application of the produced composite wood material by adjusting the material properties to meet the specific requirements of the application. It is also possible to acetylate the materials both before and after the glueing and pressing steps, resulting in a heterogeneously acetylated composite material that still has some degree of acetylation in the deeper parts of the pressed material.

[0083] In a further presently preferred embodiment, the step of acetylating the lignocellulosic biomass and / or the step of acetylating the lignin includes acetylation with acetic anhydride.

[0084] The invention further relates to a composition obtainable by the method according to the invention.

[0085] The composition obtainable by the method according to the invention provides the same or similar effects and advantages as those described for the composition according to the invention, the composite wood material according to the invention, circular composite wood material according to the invention, and method for manufacturing a composition according to the invention.

[0086] The invention also relates to a method for producing a High Pressure Laminate (HPL) material, comprising the steps of:

[0087] dissolving lignin in a suitable solvent providing a lignin solution;

[0088] infusing paper with the resulting lignin solution providing lignin infused paper; drying and curing the resulting lignin infused paper until the solvent has evaporated to an amount of at most 10 wt.% of the infused paper providing dried and cured lignin infused paper;

[0089] stacking the dried and cured lignin infused paper into multiple layers providing stacked dried and cured infused paper; andhot-pressing the resulting stacked dried and cured infused paper into HPL like materials at a temperature in the range of 100 °C to 220 °C and a pressure in the range of 1 MPa to 20 MPa, with a production time in the range of 10 seconds to 300 seconds per millimeter pressed material with regard to thickness.

[0090] The method for producing a HPL material provides the same or similar effects and advantages as those described for the composition according to the invention, the wood composite material according to the invention, circular wood composite material according to the invention, method for manufacturing a composition according to the invention, and composition obtainable by the method according to the invention.

[0091] In a presently preferred embodiment according to the invention, the step of dissolving comprises dissolving raw lignin in a suitable solvent providing a lignin solution.

[0092] It is noted that raw lignin may also be referred to as isolated lignin.

[0093] In a further presently preferred embodiment according to the invention, the paper comprises cellulose and hemicellulose, wherein one or more of the cellulose, hemicellulose, lignin are acetylated.

[0094] Suitable solvents may be selected from acetone, alcohols, esters, ethers, ethyl acetate, benzenes, ketones, or other organic solvents that do not have harmful effects to human and environmental health. Most lignins have very high solubility in solvents such as alkali water, dimethylformamide (DMF) or dimethylsulfoxide (DMSO). Preferably, the solvent is absent or only present in trace amounts after the curing and drying step. In an embodiment, at least 5 dry wt.% lignin is added. Infusion is performed by applying the dissolves lignin to the paper substrate. The infusion may be performed for several minutes, but may also take up to several days to achieve deep impregnation. After drying and curing, the papers are stacked onto each other in multiple layers. The drying is preferably performed such that the solvent such that the solvent has evaporated to an amount of at most 10 wt.% of the infused paper, preferably 8 wt.%, more preferably 6 wt.%, even more preferably 5 wt.%, Even more preferably 4 wt.%, even more preferably 3 wt.%, even more preferably 2 wt.%, even more preferably 1 wt.%, even more preferably 0.5 wt.%, and most preferably substantially evaporated. The number of layers selected depends on the specific application. When a larger number of layers is selected, the final composite material will have a higher stiffness but lower elasticity, while fewer layers have an opposite effect. An advantage of this method is that the material is evenly acetylated throughout the composite material as all the paper layers are similarly acetylated, no matter how thick the final material is. Alternatively, the operator may choose different degrees of acetylation for different paper layers and stack the layers accordingly, thereby creating a heterogeneously acetylated composite material.

[0095] The step of hot-pressing may be performed with generic hot-presses available and can be performed with or without a mold.It is noted that paper and solvents such as acetone are widely available. Paper may be used in the form of paper fibers, but also whole paper sheets. The lignin used can be of a comparable molecular weight and structure as the lignin present in the lignocellulosic mass but may also have different properties. By varying these properties, the operator can change the structural characteristics of the material produced. The method can be performed in conjunction with, before, or after the other methods according to the invention.

[0096] In a further presently preferred embodiment, the method according to the invention further comprises the step of acetylating the lignin.

[0097] In a further presently preferred embodiment, the method further comprises the step of acetylating the cellulose and / or hemicellulose which is present in the paper.

[0098] It was found that the step of acetylating the lignin and / or the step of acetylating the cellulose and / or hemicellulose which is present in the paper provides efficiently and effectively a High Pressure Laminate.

[0099] The invention also relates to a HPL like material obtainable by the method according to the invention.

[0100] The invention will be further illustrated in the Examples below.

[0101] Further advantages, features and details of the invention are elucidated on the basis of preferred embodiments thereof, wherein reference is made to the accompanying drawings, in which:

[0102] Figure 1: shows a schematic overview of a method according to the invention; and Figure 2: shows a schematic overview of a further method according to the invention. Method 10 (Figure 1) for manufacturing a composition according to the invention, follows a sequence of different steps.

[0103] In an illustrated embodiment method 10 may start with step 12 of mixing lignocellulosic biomass in the range of 70 dry wt.% to 95 dry wt.% with lignin in the range of 5 dry wt.% to 30 dry wt.% providing a mixture. Said step 12 followed by step 14 of hot-pressing the resulting mixture at a temperature in the range of 100 °C to 220 °C and a pressure in the range of 1 MPa to 20 MPa, for a time in the range of 10 seconds to 300 seconds per millimeter pressed mixture. Furthermore, step 14 is followed by step 16 of curing the mixture.

[0104] In addition, method 10 may further comprise step 18 of acetylating the lignocellulosic biomass and / or step 20 of acetylating the lignin. Step 18 and / or step 20 may be performed before, during and / or after any one of the steps 12, 14, and 16.

[0105] Method 22 (Figure 2) represents another method for manufacturing a composition according to the invention, and follows a sequence of steps.

[0106] In an illustrated embodiment method 22 may start with step 24 of dissolving raw lignin in a suitable solvent providing a lignin solution, followed by step 26 of infusing paper with lignin solution, providing lignin infused paper. Said step 26 is followed by step 28 in which the lignin infused paperis dried and cured, which step 28 is subsequently followed by step 30 in which the paper is stacked into multiple layers. In the following step 32, this stacked paper is then hot-pressed into HPL material 13 at a temperature in the range of 100 °C to 220 °C and a pressure in the range of 1 MPa to 20 MPa, with a production time in the range of 10 seconds to 300 seconds per millimeter pressed material with regard to thickness.

[0107] EXAMPLE 1

[0108] A composition comprising lignocellulosic biomass and exogenously supplied soda lignin was produced according to the method of the invention. Briefly, sheets of bleached kraft paper (based on eucalyptus) were ground down to fibres in a knife mill with a 0.5 mm sieve. Pure eucalyptus cellulose originating from the paper fibres and exogenous (technical) lignin were weighed and dry mixed into a homogeneous composition with a 70 / 30 dry wt. % distribution of cellulose to lignin. The composition was then added into a mold and hot-pressed into a plate material. The mechanical properties of the resulting material were tested according to the European Standards NEN-EN 622-5. This resulted in the values shown in Table 1, showing that the MDF material according to the invention has excellent bending strength, modulus of elasticity and compressive strength compared to generic non-acetylated MDF plates glued with chemical adhesive.

[0109] Property Minimal Generic MDF (plate MDF produced from a requirements thickness of 4-6 mm) composition according according to NEN to the invention (plate EN 622-5 (plate thickness of 4-6 mm) thickness of 4-6

[0110] mm) Bending strength (N / mm2) 34 35-36 31.63-43.72 Modulus of elasticity (N / mm2) 3000 4000 12700-29150

[0111]

[0112] Compressive strength (N / mm2) / 10 130

[0113] Table 1 Mechanical properties of Generic Medium Density Board material with chemical adhesive, and Medium Density Fibreboard produced according to the method of the invention which have been tested according to NEN EN 622-5.

[0114] EXAMPLE 2

[0115] An acetylated composition according to the invention comprising acetylated hemp fibers and exogenously supplied soda lignin was produced according to the method of the invention. Chopped hemp was ground down to in a knife mill to fibers with a length between 6 and 20 mm and acetylated using acetic anhydride. The resulting acetylated cellulose fibers and the exogenous lignin were weighed and dry mixed into a homogeneous composition with a 70 / 30 dry wt. % distribution ofcellulose to lignin. The composition was then added into a mold and hot-pressed into a plate material. The mechanical properties of the resulting material were tested according to the European Standards NEN EN 622-5. This resulted in the values shown in Table 2. The material according to the invention boasts excellent mechanical properties adhering to the minimal requirements, without the use of any chemical adhesive.

[0116] Property Minimal requirements MDF produced from an

[0117] according to NEN EN 622- acetylated composition

[0118] 5 (plate thickness of 4-6 according to the invention

[0119] mm)

[0120] Bending strength 34 34-36

[0121] (N / mm2)

[0122] Modulus of 9000 25000-29000

[0123] elasticity (N / mm2)

[0124] Swelling in

[0125] thickness after cycle 25 < 25

[0126] testing

[0127] (%)

[0128] Internal bond after

[0129] cycle testing

[0130] (N / mm2) 0.35 < 0.35

[0131] Internal bond after

[0132] swell test (N / mm2) 0.20 < 0.20

[0133]

[0134] Table 2 Mechanical properties of a Medium Density Fibreboard made of a composition according to the invention, produced according to the method of the invention which have been tested according to NEN EN 622-5.

[0135] EXAMPLE 3

[0136] The amounts of cellulose, hemicellulose, and lignin was investigated for several plants that may be used as source of plant material in the composition and the material of the invention. The plant material was glued by addition of a range of different amounts of exogenous lignin as adhesive, which lignin was furthermore acetylated to different degrees according to the invention. The structural properties of the resulting compositions and materials was also assessed. The results are summarized in Table 3. It can be seen that the application of higher amounts of acetylated lignin results in materials with an excellent combination of stiffness, bending strength, and internal bond, while boasting a very low water absorption and thickness swelling when submerged in water forextended period of time. It can also be seen that the use of different starting material can influence the eventual structural properties of the compositions and materials produced therefrom. Table 4 shows the cellulose, hemicellulose, and lignin contents of a wide variety of plant species, material of which may also be used in as source for the composition of the invention. Amount of lignin and degree of acetylation is suitably chosen based on the initial ratio of the components in the plant material.

[0137] Water Cellulose Hemicellulose Lignin WPG Exogenous

[0138] Material Exogenous Bending

[0139] (wt%) (wt%) (wt%) Acytelated Lignin (wt%) Stiffness strength absorption Thickness Internal swelling bond (%) Lignin (wt%) test

[0140] Hemp 10-22 low low high high very low 60-70 15-20 5-10 0 5

[0141] Hemp 10-22 medium very high medium medium low 60-70 15-20 5-10 0 10

[0142] Hemp 10-22 high high low low medium 60-70 15-20 5-10 0 20

[0143] Hemp 10-22 very high medium very low very low high 60-70 15-20 5-10 0 30

[0144] Hemp 10-22 high high very low very low high 60-70 15-20 5-10 10 20

[0145] Hemp 10-22 medium very high very low very low medium 60-70 15-20 5-10 10 10

[0146] Hemp 10-22 low very high low low low 60-70 15-20 5-10 5 5

[0147] Sorqhum 10-22 low low high high very low 60-70 15-20 5-10 0 5

[0148] Sorghum 10-22 medium very high medium medium low 60-70 15-20 5-10 0 10

[0149] Sorghum 10-22 high high low low medium 60-70 15-20 5-10 0 20

[0150] Sorghum 10-22 very high medium very low very low high 60-70 15-20 5-10 0 30

[0151] Sorghum 10-22 high high very low very low high 60-70 15-20 5-10 10 20

[0152] Sorghum 10-22 medium very high very low very low medium 60-70 15-20 5-10 10 10

[0153] Sorghum 10-22 low very high low low low 60-70 15-20 5-10 5 5

[0154] 10-22 low low high high very low miscanthus 60-70 15-20 5-10 0 5

[0155] 10-22 medium very high medium medium low miscanthus 60-70 15-20 5-10 0 10

[0156] 10-22 high high low low medium miscanthus 60-70 15-20 5-10 0 20

[0157] 10-22 very high medium very low very low high miscanthus 60-70 15-20 5-10 0 30

[0158] 10-22 high high very low very low high miscanthus 60-70 15-20 5-10 10 20

[0159] 10-22 medium very high very low very low medium miscanthus 60-70 15-20 5-10 10 10

[0160] 10-22 low very high low low low miscanthus 60-70 15-20 5-10 5 5

[0161] Radiata

[0162] 40-44 10-21 low low high high very low Pine 25-30 25-30 0 5

[0163] Radiata

[0164] 40-44 10-21 medium very high medium medium low Pine 25-30 25-30 0 10

[0165] Radiata

[0166] 40-44 10-21 high high low low medium Pine 25-30 25-30 0 20

[0167] Radiata

[0168] 40-44 10-21 very high medium very low very low high Pine 25-30 25-30 0 30

[0169] high high very low very low high Spruce 40-60 25-30 25-30 10-20 10 20

[0170] medium very high very low very low medium Spruce 40-60 25-30 25-30 10-20 10 10

[0171] low very high low low low Spruce 40-60 25-30 25-30 10-20 5 5

[0172] Spruce

[0173] (non

[0174] high high medium medium high acetylated) 40-60 25-30 25-30 0 10 20

[0175]

[0176] Spruce

[0177] (non

[0178] acetylated) 40-60 25-30 25-30 0 10 10 medium very high high high medium Spruce

[0179] (non

[0180] acetylated) 40-60 25-30 25-30 0 5 5 low very high very high very high low Cellulose

[0181] (non

[0182] acetylated) 100 0 0 0 0 5 low low very high very high very low Cellulose

[0183] (non

[0184] acetylated) 100 0 0 0 0 10 medium very high very high very high low Cellulose

[0185] (non

[0186] acetylated) 100 0 0 0 0 20 high high high high medium Cellulose

[0187] (non

[0188] acetylated) 100 0 0 0 0 30 very high medium high high high Cellulose 100 0 0 32-46 10 20 high high very low very low high Cellulose 100 0 0 32-46 10 10 medium very high very low very low medium

[0189]

[0190] Cellulose 100 0 0 32-46 5 5 low very high low low low

[0191] Table 3 Percentages of cellulose, hemicellulose and lignin in various plants sources that may be used for the composition of the invention. Additionally, the structural properties of the resulting composition that has been glued with various amounts of lignin, which lignin is acetylated to various degrees. WPG is the percentage weight increase of the material after acetylation through the substitution of hydroxyl- groups by acetyl-groups.

[0192] Exogenous

[0193] Acytelated Exogenous Cellulose Hemicellulose Lignin WPG Lignin Lignin Material (wt%) (wt%) (wt%) (%) (wt%) (wt%) Bamboo 40-50 20-25 20-30 15-25 0-90 0-90

[0194] 10-15

[0195] Straw 35^10 (36) 30-35 (27) (17) 8-20 0-90 0-90

[0196] Hemp 60-70 15-20 5-10 10-22 0-90 0-90

[0197] 15-25

[0198] Sorghum 3C -0 (45) 25-30 (25) (18) 8-18 0-90 0-90

[0199] Miscan thus 40-50 20-30 10-20 10-20 0-90 0-90 Bagasse 4C -5 25-30 15-20 12-23 0-90 0-90

[0200] Jute 60-65 10-15 5-10 18-25 0-90 0-90

[0201] Coir Fibers 30-35 0-90

[0202] Flax 65-75 15-20 2-5 15-25 0-90 0-90

[0203] Kenaf 60-70

[0204]

[0205] 20-25 10-15 12-22 0-90 0-90

[0206] Corn Stover 35^10 30-35 10-20 8-18 0-90 0-90 Corncob 31 43 3 0-90 0-90

[0207] 15-20

[0208] Switchgrass 40^15 (41) 25-30 (30) (17) 10-20 0-90 0-90

[0209] Palm Fiber 30-35 25-30 35^10 5-15 0-90 0-90

[0210] Rice Straw 40 18 6 0-90 0-90

[0211] Rice Husk 30-35 25-30 20-25 8-18 0-90 0-90

[0212] Rice Hull 32 33 16 0-90 0-90

[0213] Wheat Straw 62 19 14 0-90 0-90Wheat Husk 30^10 30-35 15-20 8-20 0-90 0-90 Eucalyptus

[0214] Fiber 45-55 20-30 20-25 12-25 0-90 0-90 Pine Needle 40^15 25-30 25-30 10-20 0-90 0-90 Reed

[0215] (Phragmites) 35^15 25-30 15-20 10-20 0-90 0-90 Poplar 40-50 20-30 20-25 10-22 0-90 0-90 Agave Fiber 60-65 15-20 10-15 12-20 0-90 0-90 Napier Grass 35^10 25-30 20-25 8-18 0-90 0-90 Cotton Stalks 40-50 20-25 20-30 10-22 0-90 0-90 Cotton 93 3 0 0-90 0-90 Sisal fibers 43-88 0-53 4-12 0-90 0-90 Sisal 65 12 10 0-90 0-90 Pineapple 73 7 11 0-90 0-90 Pineapple leaf

[0216] fibers 79-83 13-18 3-4 0-90 0-90 Sago frond 68 3 4 0-90 0-90 Banana fiber 49 12 14 0-90 0-90 Oil palm fiber 40 32 19 0-90 0-90 Oil palm leaf 44 36 19 0-90 0-90 Passiflora

[0217] foetida 40 36 24 0-90 0-90

[0218] Radiata Pine 40^15 25-30 25-30 10-22 0-90 0-90 Pine 40^15 (55) 25-30 25-30 10-20 0-90 0-90 Spruce 40^15 (57) 25-30 25-30 10-20 0-90 0-90 Fir 40^15 (55) 25-30 25-30 10-20 0-90 0-90 Cedar 35^10 25-30 25-35 8-18 0-90 0-90 Douglas Fir 40^15 (55) 25-30 25-30 10-20 0-90 0-90 Hemlock 40^15 25-30 25-30 10-18 0-90 0-90 Earch 40^15 25-30 25-30 10-20 0-90 0-90 Oak 40^15 (45) 25-30 20-25 15-25 0-90 0-90 Maple 40-50 25-30 20-25 15-22 0-90 0-90 Birch 45-50 (49) 20-25 20-25 12-22 0-90 0-90 Ash 40^15 20-25 20-25 15-25 0-90 0-90 Beech 40-50 (49) 20-25 20-25 12-20 0-90 0-90 Teak 45-50 20-25 25-30 10-18 0-90 0-90 Mahogany 45-50 20-25 25-30 12-20 0-90 0-90 Poplar 40-50 (53) 20-30 20-25 10-22 0-90 0-90 Eucalyptus 45-55 20-30 20-25 12-25 0-90 0-90Table 4 Cellulose, hemicellulose, and lignin ratios in various plant species that may be used as source of plant material in the invention.

[0219] EXAMPLE 4

[0220] In a further experiment, a panel (entry 1 of Table 5) of 30 cm x 30 cm x 0.5 cm (1 x w x h) was made from the composition according to the invention. Said composition comprised acetylated lignin, wherein the acetylated lignin has an weight increase of about 20% compared to the lignin which was not acetylated. In other words, the molecular weight of the acetylated lignin was about 20% higher compared to (raw) technical / exogenous lignin. Furthermore, the composition comprised 70 dry wt.% cellulose, 15 dry wt.% hemicellulose, and 15 dry wt.% lignin. It is noted that the 15 dry wt.% lignin refers to added lignin / technical lignin / exogeneous lignin.

[0221] As comparison, a similar panel (entry 2 of Table 5) was made using lignin which was not acetylated.

[0222] The load bearing in humid conditions was tested for both panels according to NEN-EN 622-5. It was found that the acetylated lignin increases the elasticity (see Table 5). Similar results were achieved using different concentrations of cellulose, hemicellulose, and lignin, wherein (part of) the lignin was acetylated.

[0223] Entry avg_Em std_Em avg_Fm std_Fm 1 941.67 342.00 5.70 1.96 2 1882.21 568.81 9.94 2.66

[0224]

[0225] Table 5 Determined values for elastic modulus (Em) and Bending strength (Fm) using the average (avg) Em or Fm, and standardized (std) Em or Fm

[0226] EXAMPLE 5

[0227] In a further experiment, composition according to invention comprising acetylated cellulose, acetylated hemicellulose, and / or acetylated lignin were formed and tested (see Table 6). It is noted that the lignin disclosed in Table 6 refers to added lignin / technical lignin / exogeneous lignin. It is noted that the columns reflecting acetylated refer to the increase of molecular weight of the (raw) technical / exogenous lignin after acetylation.

[0228] Acetylated Acetylated Acetylated

[0229] Cellulose Hemicellulose (increase Lignin (increase # (increase molecular

[0230] (dry wt.%) (dry wt.%) molecular weight (wt.%) molecular weight weight in %)

[0231] in %) in %) 1 30 0 30 0 40 0 2 30 0 30 0 40 50 3 50 0 10 0 40 50

[0232]

[0233] 4 70 0 10 0 20 50 5 30 0 10 0 60 50 6 10 0 10 0 80 50 7 30 25 30 0 40 0 8 30 25 30 0 40 50 9 30 0 30 25 40 0 10 30 0 30 25 40 50

[0234]

[0235] Table 6 Samples of the composition according to the invention

[0236] The aforementioned compositions (Table 6) were used to make panels of 30 cm x 30 cm x 0.5 cm (1 x w x h).

[0237] The load bearing in humid conditions was tested for all panels according to NEN-EN 622-5 (see Table 7). It was found that acetylation of the cellulose, hemicellulose, and / or lignin increased the elasticity of plates made of the composition according to the invention.

[0238] # Em (gPa) Fm (mPa) Internal bond (mPa) 1 34 38 0.9 2 22 32 0.8 3 24 34 0.8 4 6 29 0.85 5 24 26 0.7 6 22 24 0.7 7 29 35 1 8 27 34 0.9 9 33 35 0.8 10 31 35 0.7

[0239]

[0240] Table 7 Determined values for elastic modulus and bending strength and internal bond The present invention is by no means limited to the above described preferred embodiments and / or experiments thereof. The rights sought are defined by the following claims within the scope of which many modifications can be envisaged.

Claims

CLAIMS1. Composition comprising cellulose, hemicellulose, and lignin, wherein one or more of the cellulose, hemicellulose, lignin are acetylated.

2. Composition according to claim 1, wherein the cellulose is acetylated.

3. Composition according to any one of the preceding claims, wherein the lignin is acetylated.

4. Composition according to any one of the preceding claims, wherein the cellulose, hemicellulose, and lignin are acetylated.

5. Composition according to any one of preceding claims, wherein 5 dry wt.% to 90 dry wt.% of the one or more of the cellulose, hemicellulose, lignin is acetylated, preferably 15 dry wt.% to 90 dry wt.%.

6. Composition according to any one of the preceding claims, wherein the cellulose is present in an amount in the range of 30 dry wt.% to 70 dry wt.%, preferably present in an amount in the range of 40 dry wt.% to 60 dry wt.%, more preferably present in an amount in the range of 45 dry wt.% to 55 dry wt.%.

7. Composition according to any one of the preceding claims, wherein the hemicellulose is present in an amount in the range of 10 dry wt.% to 30 dry wt.%, preferably present in an amount in the range of 10 dry wt.% to 25 dry wt.%, more preferably present in an amount in the range of 10 dry wt.% to 20 dry wt.%.

8. Composition according to any one of the preceding claims, wherein the lignin is present in an amount in the range of 5 dry wt.% to 80 dry wt.%, preferably present in an amount in the range of 15 dry wt.% to 70 dry wt.%, more preferably present in an amount in the range of 35 dry wt.% to 65 dry wt.%.

9. Composition according to any one of preceding claims, the lignin comprises exogenous lignin.

10. Composition according to the foregoing claim, wherein the exogenous lignin is one or more selected from the group of soda lignin, kraft lignin, and lignins produced through sulphite processing and neutral sulphite semichemical processing.

11. Composition according to claim 9 or 10, wherein the exogenous lignin is acetylated.

12. Composition according to any one of preceding claims, wherein the cellulose, hemicellulose, and lignin are provided in the form of lignocellulosic biomass.

13. Composition according to claim 12, wherein the lignocellulosic biomass is selected from the group of wood fibers, paper fibers, and crop-based fibers..

14. Composite wood material comprising the composition of any one of preceding claims.

15. Composite wood material according to claim 14, wherein the material has, in order of increased preference, a moist percentage of at most 10 wt.%, at most 9 wt.%, at most 8 wt.%, at most 7 wt.%, at most 6 wt.%, at most 5 wt.%, of at most 4 wt.%, of at most 3 wt.%, and most preferably of at most 2 wt.%.

16. Composite wood material according to claim 14 or 15, wherein the plate material has a moisture absorption of at most 5 wt.% when exposed to water for 24 hours at room temperature.

17. Circular Composite wood material, obtainable by the shredding and subsequently re-glueing with lignin of composite wood material according to any one of claims 14 to 16.

18. Plate or sheet material comprising the composite wood material of any of the preceding claims 14 to 17.

19. Method for manufacturing a composition according to any one of the claims 1 to 13, comprising the steps of:mixing lignocellulosic biomass in the range of 70 dry wt.% to 95 dry wt.% with lignin in the range of 5 dry wt.% to 30 dry wt.% providing a mixture, wherein the lignocellulosic biomass comprises cellulose, hemicellulose, and wherein one or more of the cellulose, hemicellulose, lignin are acetylated;hot-pressing the resulting mixture at a temperature in the range of 100 °C to 220 °C and a pressure in the range of 1 MPa to 20 MPa, for a time in the range of 10 seconds to 300 seconds per millimeter pressed mixture; andcuring the mixture.

20. Method according to claim 19, wherein a mold is used in the hot-pressing step.

21. Method according to claim 19 or 20, wherein lignin with a different structure and / or molecular weight is used than the lignin that is present in the lignocellulosic biomass.

22. Method according to any one of claims 19 to 21, further comprising the step of acetylating the lignocellulosic biomass, preferably wherein the step of acetylating the lignocellulosic biomass is performed before the step of mixing.

23. Method according to any one of claims 19 to 22, further comprising the step of acetylating the lignin, preferably wherein the step of acetylating the lignin is performed before the step of mixing.

24. Method according to any one of preceding claims 19 to 23, wherein the step of acetylating the lignocellulosic biomass and / or the step of acetylating the lignin is performed after the step of curing.

25. Method according to any one of preceding claims 22 to 24, wherein the step of acetylating the lignocellulosic biomass and / or the step of acetylating the lignin includes acetylation with acetic acid anhydride.

26. Composition obtainable by the method according to any one of claims 19 to 25.

27. Method for producing a High Pressure Laminate (HPL) material, comprising the steps of:dissolving lignin in a suitable solvent providing a lignin solution with a concentration of at least 5 dry wt.%;infusing paper with the resulting lignin solution providing lignin infused paper, wherein the paper comprises cellulose and hemicellulose;wherein one or more of the cellulose, hemicellulose, lignin are acetylated,drying and curing the resulting lignin infused paper until the solvent has evaporated to an amount of at most 10 wt. % of the infused paper providing dried and cured lignin infused paper;stacking the dried and cured lignin infused paper into multiple layers providing stacked dried and cured infused paper; andhot-pressing the resulting stacked dried and cured infused paper into HPL like materials at a temperature in the range of 100 °C to 220 °C and a pressure in the range of 1 MPa to 20 MPa, with a production time in the range of 10 seconds to 300 seconds per millimeter pressed material with regard to thickness.

28. HPL material obtainable by the method according to claim 27.

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