Method for producing modified wooden material, 5-HMF resinification solution, and modified wooden material

Abstract

The present invention discloses a method for producing a modified wooden material. Specifically disclosed is a method for producing a modified wooden material, said method comprising: 1) a step for causing permeation, into a wooden material, of a 5-hydroxymethylfurfural (5-HMF) resinification solution containing 5-HMF and an inorganic salt for promoting polymerization of the 5-HMF; and 2) a step for polymerizing the 5-HMF of the permeated 5-HMF resinification solution in the wooden material by means of heating.

Description

Method for producing modified wood material, 5-HMF resinification solution, and modified wood material

[0001] The present invention relates to a method for modifying wood materials, i.e., a method for producing modified wood materials (modified wood materials). The present invention also relates to a solution for such a method and to wood materials modified by treatment with the solution.

[0002] Wood materials include hardwoods and softwoods. For example, tropical hardwoods are generally hard and resistant to decay, so they are used for furniture, interior materials such as flooring, and exterior materials such as wood decks.

[0003] Special Publication No. 2005-533688

[0004] In order to make wood materials more suitable for use, it is conceivable to modify the wood materials.

[0005] The present invention aims to modify wood materials.

[0006] As a result of intensive research into the above-mentioned problems, the present inventors have found that desired properties can be imparted to wood materials by using, as a solution for modifying wood materials, a furan derivative resinification solution such as a 5-HMF resinification solution that combines a furan derivative, typified by 5-HMF, and a specific agent that promotes at least partial polymerization and / or adhesion to wood materials, such as an inorganic salt and / or its hydrate or anhydride and / or an organic acid and / or the hydrate, anhydride and / or salt that the organic acid can form, and have thereby completed the present invention.

[0007] The present invention provides a method for producing a modified wood material, comprising the steps of: 1) impregnating a wood material with a furan derivative resinification solution, such as a 5-HMF resinification solution, containing a furan derivative, typified by 5-HMF, and an agent that promotes polymerization of at least a portion of the furan derivative and / or adhesion to the wood material, for example, an inorganic salt and / or a hydrate or anhydride thereof and / or an organic acid and / or a hydrate, anhydride and / or salt thereof, and 2) polymerizing at least a portion of the furan derivative in the impregnated 5-HMF resinification solution in the wood material and / or adhering to the wood material.

[0008] The present invention also provides a furan derivative resinification solution, such as a 5-HMF resinification solution, suitable for use in the above-mentioned production method. Specifically, the present invention provides a solution for modifying wood materials, comprising a furan derivative, such as 5-HMF, and an agent that promotes at least partial polymerization and / or adhesion of the furan derivative, such as 5-HMF, to the wood material, such as an inorganic salt and / or its hydrate or anhydride and / or an organic acid and / or the hydrate, anhydride and / or salt that the organic acid can form.

[0009] The present invention also provides a modified wood material obtained by the above-mentioned production method. Specifically, the present invention provides a modified wood material modified by the above-mentioned production method, which contains at least a polymerized and / or attached furan derivative such as 5-HMF.

[0010] In the present invention, wood materials can be modified.

[0011] More specifically, a furan derivative resinizing solution such as a 5-HMF resinizing solution used for modification can impart to a wood material, by modifying the wood material with the solution, at least one property selected from the group consisting of superior anti-swelling ability (ASE) and bending strength, compressive strength, hardness, etc.

[0012] One embodiment of the invention will now be described in more detail.

[0013] Various numerical values ​​and ranges mentioned in this specification are intended to include the lower or upper limit numerical value itself, unless a special term such as "less than" or "more than / greater than" is used. In other words, for example, a numerical range such as 1 to 10 can be interpreted as including the lower limit of "1" and the upper limit of "10."

[0014] [Findings that Form the Basis of the Present Disclosure] In recent years, excessive cutting of trees, such as tropical broadleaf trees, has progressed, and their depletion has become a problem.

[0015] Meanwhile, the stock of domestically grown coniferous trees is increasing, spurring the development of new uses and the exploration of added value for domestic coniferous wood. However, when attempting to use domestic coniferous wood as a substitute for tropical hardwood, appropriate care is required in at least one of the following areas. For example, when using coniferous wood as a substitute for hardwood, it is necessary to improve its durability (e.g., resistance to wood-decay fungi) and hardness. Furthermore, using durable and hard hardwood as exterior construction materials such as wood decks presents challenges. Wood, especially high-density, hard wood, experiences significant dimensional change with changes in moisture content, resulting in frequent warping and cracking. To prevent this, measures such as using thick bolts to secure the wood are essential, which requires significant construction effort. Furthermore, such thick bolts are often pulled out by the wood's deformation forces. Wood materials used for exterior construction such as wood decks are required to have good durability, minimal dimensional change due to fluctuations in moisture content (i.e., high dimensional stability), and hardness to prevent cracking and scratches.

[0016] The technology described in JP 2005-533688 A (Patent Document 1) uses acetone or a low-boiling alcohol as a cosolvent. It cannot be said that a furan derivative monomer solution containing such a cosolvent can sufficiently inhibit polymerization of the furan derivative, at least during storage at room temperature. If the furan derivative polymerizes and becomes polymeric during storage, i.e., before being impregnated into the wood material, it becomes difficult to achieve uniform penetration into the wood material. Therefore, it can be said that this technology makes it difficult to sufficiently impregnate the furan derivative into wood materials (e.g., wood materials made from domestic coniferous trees such as cedar and cypress). Moreover, even if penetration is achieved, it is difficult to achieve satisfactory modification of the wood material.

[0017] In light of the above-mentioned background, the present applicants have filed an invention relating to a method for producing wood materials modified with furan derivatives (International Patent Application No. PCT / JP2021 / 027813). The invention in the previous application required the incorporation of a stabilizer to stabilize the furan derivative, furfuryl alcohol, in aqueous solution. Furthermore, because the low-boiling-point furan derivative monomer evaporates and disperses from the wood during the polymerization heating process, resulting in a decrease in yield, a two-stage heating process was required: first, the furan derivative monomer impregnated into the wood material was heated at a relatively low temperature to allow polymerization to proceed to a certain extent while suppressing evaporation, and then the material was heated to a high temperature to complete the polymerization.

[0018] In addition to the problems solved in the previous application filed by the applicants, the present disclosure attempts to solve the problems that the invention in the previous application required the incorporation of a stabilizer and that two heating steps were required to resinify wood materials into furan derivatives by using 5-HMF, a type of furan derivative, and / or its derivatives.

[0019] [Manufacturing Method of the Present Invention] The present invention provides a method for manufacturing a modified wood material. That is, the present invention provides a method for modifying a wood material by providing a method for manufacturing a modified wood material.

[0020] The production method of the present invention comprises the steps of: 1) impregnating a wood material with a furan derivative resinification solution containing a furan derivative and an agent that promotes polymerization of at least a portion of the furan derivative and / or adhesion to the wood material, such as an inorganic salt and / or a hydrate or anhydride thereof and / or an organic acid and / or a hydrate, anhydride and / or salt thereof that the organic acid can form; and 2) polymerizing at least a portion of the furan derivative in the impregnated furan derivative resinification solution in the wood material and / or causing it to adhere to the wood material.

[0021] In this disclosure, the term "furan derivative resinification solution" refers to a liquid used in a process for incorporating resin into at least a portion of a wood material, primarily through polymerization of a furan derivative. In other words, "resinification" as used herein essentially refers to a state in which a resin component formed by polymerization of the furan derivative in the solution or an attached furan derivative is contained in the wood material. Hereinafter, the "furan derivative resinification solution" will also be referred to simply as "solution." Furthermore, in this disclosure, "attachment" of a furan derivative to a wood material refers to the binding of the furan derivative to the exterior (or surface) or interior of the wood material, or the penetration of a portion of the furan derivative into the wood material.

[0022] In the present disclosure, "room temperature" refers to the temperature of an environment (e.g., ambient temperature) that is not artificially changed by those skilled in the art, such as by heating or cooling, and typically refers to a temperature of 15 to 35°C, e.g., 20 to 30°C or 23 to 27°C.

[0023] Furthermore, in the present disclosure, "heating" refers to an artificial increase in temperature to favorably promote the polymerization of the furan derivative, and means heating the wood material or its surrounding environment to, for example, 40°C to 180°C, 60°C to 160°C, 70°C to 120°C, or 80°C to 100°C, or 70°C to 160°C or 80°C to 150°C. Note that, although "temperature" in the present disclosure refers to the temperature of the wood material or its surrounding environment, for simplicity or convenience, it may also be considered to be the set temperature of the equipment used in the production (for example, the temperature set by the heating / warming means of the chamber). Note that, in the present disclosure, the time period for which the wood material is kept at such a temperature may be 2 to 240 hours, for example, 4 to 168 hours, 10 to 96 hours, 10 to 80 hours, or 10 to 48 hours. In a preferred embodiment, reaction at such a temperature more suitably promotes polymerization of the furan derivative that has permeated the wood material and / or adhesion to the wood material, and the wood material wet with the furan derivative resinification solution is then dried. In the production method of the present invention, after the wood material has been permeated with the furan derivative, the wood material may be rapidly heated from room temperature. In another preferred embodiment, the wood material that has been permeated with the furan derivative is left at room temperature without heating, thereby promoting polymerization of the furan derivative that has permeated the wood material and / or adhesion to the wood material, and the wood material wet with the furan derivative resinification solution is then dried.

[0024] The "agent for promoting the polymerization of furan derivatives and / or adhesion to wood materials" in the present disclosure may act to promote the polymerization of furan derivatives and / or adhesion to wood materials, for example, during resinification of wood materials (e.g., by placing the permeation-treated wood materials at a temperature of 5°C or higher). For example, the "agent for promoting the polymerization of 5-HMF or its derivatives and / or adhesion to wood materials" in the present disclosure is an agent that acts to promote the polymerization of 5-HMF or its derivatives and / or adhesion to wood materials, for example, during resinification of wood materials (e.g., by placing the permeation-treated wood materials at a temperature of 5°C or higher). The "agent for promoting the polymerization of 5-HMF or its derivatives and / or adhesion to wood materials" may be an agent that does not promote polymerization in the form of a solution alone, but promotes the polymerization of 5-HMF or its derivatives and / or adhesion to wood materials when permeated into wood materials. Furthermore, the "agent that promotes the polymerization of furan derivatives and / or the adhesion to wood materials" in the present disclosure may act to promote the polymerization of furan derivatives and / or the adhesion to wood materials, for example, during resinification of wood materials at room temperature without heating (for example, by placing the permeation-treated wood materials at room temperature). For example, the "agent that promotes the polymerization of 5-HMF or its derivatives" in the present disclosure may act to promote the polymerization of 5-HMF or its derivatives and / or the adhesion to wood materials, for example, during resinification of wood materials at room temperature without heating (for example, by placing the permeation-treated wood materials at room temperature). In the following description of the present specification, the "agent that promotes the polymerization of furan derivatives and / or the adhesion to wood materials" and the "agent that promotes the polymerization of 5-HMF and / or its derivatives and / or the adhesion to wood materials" are sometimes referred to simply as "accelerators."

[0025] In the present disclosure, the term "wood material" typically refers to wood. The "wood material" may be, for example, a raw wood material to be used for wood products. That is, the wood material used in the manufacturing method of the present invention may be wood that has been processed or sawn from a log to have a predetermined shape.

[0026] The furan derivative used in the production method of the present invention is not particularly limited, and may be, for example, a furan skeleton to which a hydrocarbon group (e.g., a hydrocarbon group having 1 to 40, 1 to 30, 1 to 20, 1 to 10, 1 to 8, 1 to 6, 1 to 4, 1 to 3, or 1 to 2 carbon atoms) is directly bonded, i.e., a derivative substituted with such a hydrocarbon group. Examples of furan derivatives include furan substituted with at least one functional group selected from the group consisting of an alkyl group, a formyl group, a hydroxyl group, and a hydroxyalkyl group. The number of carbon atoms in each of the alkyl group, formyl group, hydroxyl group, and hydroxyalkyl group functional group may be 1 to 20, for example, 1 to 10, 1 to 8, 1 to 6, 1 to 4, 1 to 3, 1 to 2, or 1. Furthermore, the number of functional groups used for substitution may be 1 to 4 per molecule of the furan derivative, for example, 1 to 3, 1 to 2, or 1.

[0027] The furan derivative resinification solution used in the production method of the present invention includes a "furan derivative." For example, the furan derivative may be at least one polymerizable monomer selected from the group consisting of 5-hydroxymethylfurfural (5-HMF) and its derivatives. For example, 5-HMF may be commercially available. As merely one example, 5-HMF commercially available from Combi-Blocks, Tokyo Chemical Industry Co., Ltd., Fujifilm Wako Pure Chemical Industries, Ltd., Kanto Chemical Co., Ltd., etc. may be used. Furan derivatives, such as 5-HMF and / or its derivatives, can be stable in a solution using an aqueous solvent (especially a solution containing 100% water by weight). After impregnation into the wood material, the action of an accelerator promotes condensation polymerization and / or adhesion to the wood material at temperatures of 5°C or higher, making the resinification of the wood material more favorable.

[0028] Among furan derivatives, for example, when 5-HMF is used, the modified wood tends to have a higher anti-swelling ability (ASE). In a preferred embodiment, the ASE can be 50% or more, for example, 50 to 99%, 50 to 95%, or 50 to 90%. Among furan derivatives, for example, when 5-HMF is used, the modified wood tends to have a higher bending strength, compressive strength, and / or hardness. In a preferred embodiment, the bending strength can be increased by 5% or more, for example, by 7% or more, or by 10% or more, or by 5 to 70%, 5 to 60%, 5 to 50%, 5 to 40%, 5 to 30%, 5 to 20%, 5 to 15%, 7 to 70%, 7 to 60%, 7 to 50%, 7 to 40%, 7 to 30%, 7 to 20%, or 7 to 15%, etc.

[0029] The furan derivative resinification solution used in the present invention may be aqueous. In other words, the furan derivative resinification solution used in the production method of the present invention may be a solution containing the above-mentioned furan derivative, an inorganic salt and / or its hydrate or anhydride that promotes the polymerization and / or adhesion of the furan derivative to wood materials, and / or an organic acid and / or the hydrate, anhydride, and / or salt that it can form, and water as a solvent. In particular, the solvent in the furan derivative resinification solution may be an aqueous medium. This means that the solvent contained in the solution is substantially 90% by weight or more, 93% by weight or more, 95% by weight or more, or 97% by weight or more of water, or only water (100% by weight). In the present invention, the phrase "the solvent in the furan derivative resinification solution is an aqueous medium" refers to a solvent contained in the solution that is at least 90% by weight of water. Preferably, the furan derivative resinification solution may contain only water as a solvent and may not contain organic solvents such as acetone. In a simple and preferred embodiment, the furan derivative resinification solution used in the present invention may not contain acetone or the like.

[0030] More specifically, the solvent in the furan derivative resinification solution may be a simple solvent consisting of only water, rather than a solvent consisting of a mixture. Note that the solvent in the furan derivative resinification solution used in this example does not contain an organic solvent, and therefore may also be referred to as a non-organic solvent (particularly, an aqueous medium containing 100% water by weight or 100% by volume as a non-organic solvent).

[0031] When the solvent for the furan derivative resinification solution is an aqueous solvent composed solely of water, the modification of the wood material can be more effectively achieved, and the effects of the present invention can be more pronounced. Without being bound by any particular theory, this is thought to be related to the fact that the furan derivative in the furan derivative resinification solution is more likely to penetrate deeper into the wood material than when acetone or other solvents are included. While also not being bound by any particular theory, one possible reason for this is that water used as the aqueous solvent has a higher polarity and / or a smaller molecular weight than acetone or other solvents, and therefore a 100% aqueous solvent is more likely to penetrate the cell walls of wood than when acetone or other solvents are included. Furthermore, aqueous solvents can reduce costs when implementing the production method of the present invention, and are also relatively advantageous in terms of safety and environmental conservation compared to when organic solvents are used.

[0032] In the present invention, the type of water used as the aqueous solvent (i.e., an aqueous solvent consisting solely of water) is not particularly limited, and any water generally recognized as water can be used. By way of example only, the water used as the aqueous solvent may be at least one selected from the group consisting of tap water, purified water, groundwater, river water, rainwater, deionized water, distilled water, etc.

[0033] In certain embodiments, if desired, the furan derivative resinification solution used in the present invention may contain a small amount of an organic solvent, such as a monohydric alcohol, to enhance the solubility of the furan derivative.

[0034] The concentration of the furan derivative in the furan derivative resinification solution used in the production method of the present invention may be typically 5 to 50 wt % (excluding 50 wt %) based on the total weight of the furan derivative resinification solution, for example, 5 to 45 wt %, 10 to 45 wt %, 20 to 45 wt %, 20 to 40 wt %, or 25 to 35 wt %. For example, the concentration of 5-HMF and / or its derivatives in the 5-HMF resinification solution used in the production method of the present invention may be typically 5 to 50 wt % (excluding 50 wt %) based on the total weight of the 5-HMF and / or its derivatives resinification solution, for example, 5 to 45 wt %, 10 to 45 wt %, 20 to 45 wt %, 20 to 40 wt %, or 25 to 35 wt %. Such a concentration of the furan derivative, e.g., 5-HMF and / or its derivatives, can facilitate more favorable modification of woody materials. For example, by modifying wood materials with the solution, it becomes easier to impart to the wood materials more favorable anti-swelling capacity (ASE) and at least one favorable property selected from the group consisting of bending strength, compressive strength, hardness, etc.

[0035] The furan derivative resinification solution used in the production method of the present invention contains an "agent that promotes the polymerization of the furan derivative and / or its adhesion to wood materials." For example, the 5-HMF and / or derivative thereof resinification solution contains an "agent that promotes the polymerization of 5-HMF and / or its derivatives and / or its adhesion to wood materials." By incorporating such an agent into the furan derivative resinification solution, for example, the 5-HMF and / or derivative thereof resinification solution, polymerization of the furan derivative in the solution, for example, polymerization of 5-HMF and / or its derivatives and / or its adhesion to wood materials, can be more suitably promoted when the solution is impregnated into wood materials at 5°C or higher for modification treatment.

[0036] The "agent for promoting the polymerization of a furan derivative and / or its adhesion to a wood material" may be an agent that promotes the polymerization of a furan derivative and / or its adhesion to a wood material by drying at 5°C or higher or by heating. For example, the "agent for promoting the polymerization of 5-HMF and / or its derivatives and / or its adhesion to a wood material" may be an agent that promotes the polymerization of a furan derivative and / or its adhesion to a wood material by drying at 5°C or higher or by heating. Here, "promoting polymerization" means that the presence of such an agent increases the rate of the polymerization reaction of a furan derivative, such as 5-HMF and / or its derivatives, compared to when the agent is not present (for example, when a polymerizable monomer is present alone). Furthermore, the term "promoting adhesion to a wood material" means that the presence of such an agent increases the rate and amount of adhesion of a furan derivative, such as 5-HMF and / or its derivatives, to a wood material when the furan derivative has penetrated the wood material compared to when the agent is not present (for example, when a polymerizable monomer is present alone). Such an agent may be an agent that exhibits acidity, for example, weak acidity, in an aqueous solution (e.g., an aqueous solution at room temperature), and may be an agent that changes the pH of a furan derivative resinification solution, such as a 5-HMF and / or its derivative resinification solution, to the acidic side (i.e., lowers the pH). For example, such an agent may be neutral to weakly acidic, typically pH 3 to 7 (excluding "7"), in aqueous solution at room temperature, and may exhibit, for example, pH 4 to 6.5 or pH 5 to 6.

[0037] In the present disclosure, "pH" refers to hydrogen ion exponent, and may be a pH value measured in accordance with, for example, "JIS Z 8802 pH measurement method."

[0038] In the production method of the present invention, the "agent that promotes the polymerization and / or adhesion of furan derivatives to wood materials," for example, the "agent that promotes the polymerization and / or adhesion of 5-HMF and / or its derivatives to wood materials," is an inorganic salt and / or its hydrate or anhydride, and / or an organic acid and / or the hydrate, anhydride, and / or salt that it can form. In the production method of the present invention, the inorganic salt used as the "agent that promotes the polymerization and / or adhesion of furan derivatives to wood materials," for example, the "agent that promotes the polymerization and / or adhesion of 5-HMF and / or its derivatives to wood materials," may be an inorganic salt composed of an anion of chloride ion and / or sulfate ion and a cation of ammonium ion, magnesium ion, and / or hydrogen ion. Such inorganic salts can assist in more suitable modification of wood materials.

[0039] In the production method of the present invention, the "agent that promotes the polymerization and / or adhesion of a furan derivative to a wood material" is not particularly limited, as long as it promotes at least partial polymerization or adhesion to a wood material of a furan derivative resinification solution such as a 5-HMF resinification solution (preferably, a furan derivative such as 5-HMF in a furan derivative resinification solution such as a 5-HMF resinification solution that has permeated a wood material) when placed at room temperature or when heated from room temperature. For example, the "agent that promotes the polymerization and / or adhesion to a wood material of 5-HMF and / or its derivatives" may be an agent selected from the group consisting of ammonium chloride, magnesium chloride hexahydrate, maleic acid, citric acid, ammonium sulfate, and ammonium hydrogen sulfate. For example, modifying a wood material with the solution can easily impart to the wood material a more favorable anti-swelling ability (ASE) and / or at least one favorable property selected from the group consisting of bending strength, compressive strength, and hardness, particularly anti-swelling ability (ASE).

[0040] In a preferred embodiment, the "agent for promoting the polymerization of furan derivatives and / or the adhesion of 5-HMF and / or its derivatives to wood materials" may be an inorganic salt. For example, such an inorganic salt may be an inorganic salt having, as its constituents, a combination of either a chloride ion or a sulfate ion and one or two ions selected from the group consisting of an ammonium ion, a magnesium ion, and a hydrogen ion.

[0041] For example, the "inorganic salt that promotes the polymerization of a furan derivative and / or the adhesion to a wood material", e.g., the "inorganic salt that promotes the polymerization of 5-HMF and / or the adhesion of a derivative thereof to a wood material" may be at least one inorganic salt selected from the group consisting of magnesium chloride, ammonium chloride, ammonium sulfate, ammonium hydrogen sulfate, magnesium sulfate, magnesium hydrogen sulfate, and the like.

[0042] Furthermore, the organic acid or a hydrate, anhydride, or salt thereof that can be formed to be used as an "agent for promoting the polymerization and / or adhesion of furan derivatives to wood materials," for example, an "agent for promoting the polymerization and / or adhesion of 5-HMF and / or its derivatives to wood materials," in the production method of the present invention may be one or more organic acids selected from the group consisting of saturated or unsaturated aliphatic hydrocarbons having 1 to 20, 1 to 6, or 1 to 4 carbon atoms and one or more carboxy groups and / or sulfo groups, which may have halogens, amino groups, and / or hydroxy groups, and saturated or unsaturated aromatic hydrocarbons having 3 to 20, 3 to 18, or 6 to 12 carbon atoms and one or more carboxy groups and / or sulfo groups, which may have halogens, amino groups, and / or hydroxyl groups. Furthermore, the organic acid used as an "agent for promoting the polymerization of a furan derivative and / or its adhesion to a woody material", for example, an "agent for promoting the polymerization of 5-HMF and / or its derivatives and / or its adhesion to a woody material" may be a hydrate, anhydride or salt that can be formed by the above-mentioned organic acid, and one or more of these may be used in combination.

[0043] For example, the "organic acid or its hydrate, anhydride, or salt that promotes the polymerization of a furan derivative and / or adhesion to a wood material", e.g., the "organic acid or its salt that promotes the polymerization of 5-HMF and / or its derivatives and / or adhesion to a wood material", may be at least one organic acid selected from the group consisting of formic acid, acetic acid, oxalic acid, maleic acid, citric acid, glucuronic acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, camphorsulfonic acid, fluorosulfonic acid, and taurine, or a hydrate, anhydride, or salt that can be formed by these.

[0044] In a furan derivative resinification solution, for example, a 5-HMF and / or derivative thereof resinification solution, the concentration or amount of the "agent that promotes the polymerization of a furan derivative and / or adhesion to a wood material," for example, the "agent that promotes the polymerization of 5-HMF and / or derivatives thereof and / or adhesion to a wood material," may be 0.1 mol or less, 0.09 mol or less, 0.08 mol or less, 0.07 mol or less, 0.06 mol or less, 0.05 mol or less, 0.04 mol or less, 0.03 mol or less, 0.02 mol or less, etc., per mol of the furan derivative, for example, 5-HMF and / or derivative thereof, in the solution. In such cases, the lower limit may be a value greater than 0 mol. For example, taking the upper limit value of 0.1 mol as an example, the concentration or amount of the "agent that promotes the polymerization of a furan derivative and / or adhesion to a wood material", e.g., the "agent that promotes the polymerization of 5-HMF and / or adhesion to a wood material of 5-HMF and / or a derivative thereof" contained in the furan derivative resinification solution, e.g., 5-HMF and / or a derivative thereof resinification solution, may be 0.001 to 0.1 mol, such as 0.002 to 0.1 mol, 0.003 to 0.1 mol, 0.004 to 0.1 mol, 0.005 to 0.1 mol, 0.006 to 0.1 mol, 0.007 to 0.09 mol, 0.008 to 0.08 mol, or 0.009 to 0.07 mol, relative to 1 mol of the furan derivative, e.g., 5-HMF and / or a derivative thereof. Such a concentration or amount of the "agent for promoting the polymerization and / or adhesion of furan derivatives to wood materials," e.g., "agent for promoting the polymerization and / or adhesion of 5-HMF and / or its derivatives to wood materials," can help to improve the modification of wood materials. For example, modifying wood materials with the solution can easily impart to the wood materials better anti-swelling ability (ASE) and / or at least one suitable property selected from the group consisting of bending strength, compressive strength, hardness, etc.

[0045] The wood material that can be used in the manufacturing method of the present invention is not particularly limited, and any wood equivalent can be used. For example, wood materials that can be used in the manufacturing method of the present invention include at least one domestic coniferous tree selected from the group consisting of cedar, cypress, pine, larch, Yezo spruce, Abies sachalinensis, Tsuga, and fir. Wood materials also include at least one imported coniferous tree selected from the group consisting of southern yellow pine, radiata pine, Scots pine, Chinese fir, and Douglas fir. Furthermore, wood materials that can be used include solid wood from fast-growing but soft hardwoods such as poplar and / or China china, as well as wood materials that have been processed to some extent, such as laminated lumber, plywood, veneer, particleboard, and / or fiberboard, and the lamina (sawn boards), veneer, wood chips, wood flour, and / or wood fiber (pulp) that make up these materials, as well as non-woody lignocellulosic materials such as bamboo.

[0046] The wood materials modified by the manufacturing method of the present invention may be used for various indoor and / or outdoor applications, such as furniture, flooring, wood decks, exterior walls, louvers, truck bodies, musical instruments, interior and exterior construction materials, etc.

[0047] In a preferred embodiment, the wood material is softwood. In such a case, the effects of the present invention can be more pronounced. While these wood materials have traditionally had limited uses due to their low dimensional stability and / or bending strength, compressive strength, or hardness, the manufacturing method of the present invention improves these properties, potentially enabling them to be used in a wider range of applications. Such softwood may be, for example, cedar and / or cypress. The cedar and / or cypress may correspond to domestic softwood, which will contribute favorably to the development of new uses for domestic softwoods and to the demand for added value.

[0048] By way of example only, the wood material to be subjected to the modification treatment (i.e., unmodified or unmodified wood material) may have a moisture content adjusted to 30% by weight or less, for example, 25% by weight or less, 20% by weight or less, or 15% by weight or less, based on the total weight of the wood material (in this case, the lower limit may be a value of 0% by weight or more).

[0049] As described above, the furan derivative resinification solution used in the manufacturing method of the present invention, e.g., 5-HMF and / or its derivative resinification solution, preferably contains one accelerator as a solute component other than the furan derivative, e.g., 5-HMF and / or its derivative. That is, it contains an "agent that promotes the polymerization of the furan derivative and / or its adhesion to the wood material." In particular, the furan derivative resinification solution used in the manufacturing method of the present invention, e.g., 5-HMF and / or its derivative resinification solution, is a solution containing an inorganic salt, an organic salt, and / or an oxidative polymerization agent that can act as an "accelerator." This solution can facilitate more favorable modification of wood materials. For example, modifying wood materials with this solution can easily impart to the wood materials more favorable anti-swelling ability (ASE) and at least one property selected from the group consisting of bending strength, compressive strength, and hardness.

[0050] Preferably, such an accelerator (an agent that accelerates the polymerization of a furan derivative and / or its adhesion to a wood material at a temperature of 5°C or higher), such as an inorganic salt, forms a solution together with a furan derivative, such as 5-HMF and / or a derivative thereof, and a solvent (water alone or a mixed solvent containing water and an alcohol, such as ethyl alcohol). In particular, a furan derivative resinification solution, such as a 5-HMF and / or a derivative thereof resinification solution, containing an accelerator and a simple solvent consisting of water alone or a mixed solvent consisting of water and an alcohol, can achieve a more pronounced effect in modifying wood materials, as described above.

[0051] In the manufacturing method of the present invention, step 1) involves permeating a wood material with a furan derivative resinification solution, for example, 5-HMF and / or its derivatives. There are no particular limitations on the means used, as long as it contributes to permeation. For example, a chamber capable of containing the wood material and the furan derivative resinification solution, for example, 5-HMF and / or its derivatives, may be used. In step 1), the wood material may be immersed in the furan derivative resinification solution, for example, 5-HMF and / or its derivatives, and / or the furan derivative resinification solution, for example, 5-HMF and / or its derivatives, may be sprayed or applied to the wood material, and / or the wood material may be impregnated with the furan derivative resinification solution, for example, 5-HMF and / or its derivatives, under reduced pressure and / or increased pressure.

[0052] In the case of thin or small wood materials such as veneers, wood chips, wood flour and / or wood fibers (pulp), the desired penetration is easily achieved by immersion, coating, spraying, etc. On the other hand, in the case of wood materials with a cross-sectional size larger than a certain level, such as solid wood or lamina, the desired penetration is easily achieved by impregnation treatment under reduced pressure and / or pressure, i.e., the so-called reduced pressure / pressure impregnation method.

[0053] In other words, step 1) may be performed under reduced pressure below atmospheric pressure. The reduced pressure conditions may depend on the shape and / or size of the wood material to be modified, but may be, for example, reduced pressure conditions between less than atmospheric pressure and 10 hPa at a temperature range below room temperature. Under such reduced pressure conditions, the penetration of the solution into the wood material may be more favorably promoted. For example, by modifying the wood material with the solution, it becomes easier to impart to the wood material a more favorable anti-swelling capacity (ASE) and at least one favorable property selected from the group consisting of bending strength, compressive strength, and hardness. The reduced pressure conditions (e.g., the pressure in the chamber) in step 1) may be, for example, reduced pressure conditions of 700 to 10 hPa, 500 to 10 hPa, 100 to 10 hPa, 75 to 10 hPa, 50 to 10 hPa, 40 to 10 hPa, or 40 to 20 hPa. The time for which the wood material is subjected to the furan derivative resinification solution, for example, 5-HMF and / or its derivative resinification solution under reduced pressure conditions may typically be 5 minutes to 16 hours, for example, 30 minutes to 16 hours, 1 hour to 16 hours, 1 hour to 8 hours, 1 hour to 4 hours, or 1 hour to 3 hours.

[0054] In the manufacturing method of the present invention, atmospheric pressure conditions or pressurized conditions may be appropriately employed. For example, a pressurized treatment may be carried out after the above-mentioned reduced pressure treatment. In such treatment, atmospheric pressure or a higher atmospheric pressure may be employed. For example, a pressure condition (e.g., pressure inside the chamber) of 0.1 to 3 MPa or 0.3 to 2 MPa may be employed. The time for which the wood material is subjected to such pressure or pressurized conditions may typically be 15 minutes to 72 hours, for example, 30 minutes to 36 hours, or 1 hour to 12 hours.

[0055] In the production method of the present invention, in step 2), at least a portion of the furan derivative, for example, 5-HMF and / or its derivatives, that has permeated the wood material is polymerized in the wood material and / or adhered to the wood material at a temperature of 5° C. or higher. By leaving the wood material at room temperature or by heating, polymerization of the furan derivative in the furan derivative resinification solution, for example, 5-HMF and / or its derivatives, in the wood material and / or adhesion to the wood material are promoted, and the resulting modification of the resin components and / or wood material can result in the modification of the wood material.

[0056] When artificial heating is performed in step 2), there are no particular limitations on the means for doing so as long as it is possible to raise the temperature of the wood material permeated with the solution. For example, heating may be performed by raising the temperature of the chamber in which the wood material is placed (e.g., the atmospheric temperature inside the chamber).

[0057] Such heating may be performed at room temperature to 180°C. That is, step 2) in the production method of the present invention may be performed at a temperature of room temperature to 180°C. Alternatively, the heating in step 2) may be performed at a temperature of 40 to 180°C, 40 to 170°C, 40 to 160°C, 60 to 180°C, 60 to 170°C, 60 to 160°C, 80 to 180°C, 80 to 150°C, 80 to 140°C, or 80 to 120°C. Furthermore, the heating in step 2) may be performed at a temperature of 90 to 140°C, 100 to 140°C, 110 to 140°C, or 120 to 140°C. Such heating conditions may facilitate more favorable modification of the wood material; for example, modification treatment of the wood material with the solution may facilitate imparting to the wood material more favorable anti-swelling capacity (ASE) and at least one property selected from the group consisting of bending strength, compressive strength, and hardness. Furthermore, the heating temperature in step 2) (for example, the temperature inside the chamber) may be 40 to 250°C, 60 to 125°C, 60 to 120°C, or 60 to 100°C, for example.

[0058] The time for which the woody material is subjected to room temperature or heat treatment in step 2) may typically be 2 to 240 hours, for example, 4 to 168 hours, 4 to 96 hours, 10 to 96 hours, 10 to 80 hours, or 10 to 48 hours, or 4 to 48 hours, 4 to 30 hours, or 10 to 30 hours, or even 4 to 24 hours, 4 to 10 hours, or 4 to 8 hours.

[0059] The heating in step 2) may be carried out in an air atmosphere, but is not limited thereto, and heating to a relatively high temperature (e.g., heating above 100°C) may be carried out in an inert gas atmosphere such as water vapor and / or nitrogen gas.

[0060] In the heating in step 2), the wood material permeated with the solution may be dried. For example, the heating in step 2) may polymerize the furan derivative of the permeated furan derivative resinification solution, such as 5-HMF and / or its derivatives, in the wood material while drying the wood material. In other words, the heat treatment may be performed for 2 to 240 hours, or 2 to 260 hours (for example, 3 to 192 hours, 3 to 168 hours, 4 to 180 hours, or 5 to 192 hours) at a temperature of 60 to 160°C (for example, 80 to 160°C, 80 to 150°C, 90 to 150°C, 90 to 120°C, 90 to 110°C, or 100 to 150°C, 110 to 140°C, or 120 to 140°C) in a chamber containing the wood material permeated with the furan derivative resinification solution, such as 5-HMF and / or its derivatives. The heating may be carried out for a period of time (e.g., 168 hours, 4 to 96 hours, 10 to 96 hours, 10 to 80 hours, or 10 to 48 hours, or 4 to 48 hours, 4 to 30 hours, or 10 to 30 hours, or 4 to 24 hours, 4 to 10 hours, or 4 to 8 hours) to allow the polymerization of the furan derivative, for example, 5-HMF and / or its derivatives that has permeated into the wood material and / or its attachment to the wood material to proceed, and in parallel with or subsequent to this, the wood material (which is wet due to the permeation of the solution) may be dried.

[0061] Because furan derivatives, such as 5-HMF and / or its derivatives, are highly stable, the furan derivative resinification solution used in the production method of the present invention, such as a 5-HMF and / or its derivative resinification solution, may not contain a stabilizer that inhibits the undesired polymerization of furan derivatives, such as 5-HMF and / or its derivatives, in an aqueous medium (e.g., undesired polymerization that can be understood as turbidity, insolubilization, and / or separation in the solution). In other words, although it is conceivable to produce modified wood materials using such stabilizers, modified wood materials may be produced without using furan derivative resinification solutions such as a 5-HMF resinification solution (in other words, in one embodiment, the furan derivative resinification solution of the present invention does not contain "components that inhibit the polymerization of furan derivatives at room temperature (e.g., inorganic substances including inorganic salts that inhibit the polymerization of furan derivatives at room temperature)."

[0062] Alternatively, if desired, an "inorganic substance containing an inorganic salt that inhibits the polymerization of furan derivatives at room temperature" can be included in the furan derivative resinification solution for the purpose of further stabilizing a furan derivative, e.g., 5-HMF and / or its derivatives, in an aqueous solvent during long-term storage at room temperature or storage under conditions such as temperatures exceeding room temperature. For example, an "inorganic substance containing an inorganic salt that inhibits the polymerization of 5-HMF and / or its derivatives at room temperature" may be included in the 5-HMF and / or its derivative resinification solution. The "inorganic substance containing an inorganic salt that inhibits the polymerization of furan derivatives at room temperature," e.g., the "inorganic substance containing an inorganic salt that inhibits the polymerization of 5-HMF and / or its derivatives at room temperature," may be, for example, ammonia or an inorganic carbonate. Additionally or alternatively, the "inorganic substance containing an inorganic salt that inhibits the polymerization of furan derivatives at room temperature," e.g., the "inorganic substance containing an inorganic salt that inhibits the polymerization of 5-HMF and / or its derivatives at room temperature," may be in the form of, for example, ammonia or an ammonium salt.

[0063] In certain embodiments, the "inorganic substance containing an inorganic salt that inhibits the polymerization of furan derivatives at room temperature," e.g., the "inorganic substance containing an inorganic salt that inhibits the polymerization of 5-HMF and / or its derivatives at room temperature," may be at least one inorganic salt selected from ammonia, ammonium carbonate, ammonium bicarbonate, and the like. Simply put, the "inorganic substance containing an inorganic salt that inhibits the polymerization of furan derivatives at room temperature," e.g., the "inorganic substance containing an inorganic salt that inhibits the polymerization of 5-HMF and / or its derivatives at room temperature," may be, for example, ammonia, ammonium carbonate, ammonium bicarbonate, or a combination of two or three selected from the group consisting of ammonia, ammonium carbonate, and ammonium bicarbonate. This is because the undesired polymerization of furan derivatives, e.g., 5-HMF and / or its derivatives, in solution at room temperature can be inhibited at room temperature, thereby more suitably maintaining the quality stability of the solution before impregnation into wood materials, and the inorganic substance may contain an inorganic salt that does not inhibit the polymerization of furan derivatives, e.g., 5-HMF and / or its derivatives, during heating after impregnation. The term "suppressing polymerization" as used herein means that the presence of an inorganic substance containing such an inorganic salt reduces or stops the rate of polymerization of a furan derivative, such as 5-HMF and / or a derivative thereof, compared to when the inorganic substance is not present (for example, when a polymerizable monomer is present alone).

[0064] The "inorganic substance containing an inorganic salt that inhibits the polymerization of a furan derivative at room temperature", for example, the "inorganic substance containing an inorganic salt that inhibits the polymerization of 5-HMF and / or a derivative thereof at room temperature" may be an inorganic substance containing an inorganic salt that exhibits basicity in an aqueous solution (e.g., an aqueous solution at room temperature), and may be, for example, an inorganic substance containing an inorganic salt that makes a furan derivative resinification solution, for example, a 5-HMF and / or a derivative thereof resinification solution, basic or shifts the pH to a more basic side (i.e., increases the pH). Incidentally, it is believed that adding a salt such as sodium hydroxide and / or potassium hydroxide to a furan derivative resinification solution comprising a furan derivative, such as 5-HMF and / or its derivatives, an inorganic salt that promotes the polymerization of the furan derivative, which is neutral to weakly acidic at room temperature, and water, and maintaining the furan derivative resin aqueous solution, such as a 5-HMF and / or its derivative resinification solution, at a basic temperature may inhibit the polymerization of the furan derivative, such as 5-HMF and / or its derivatives, and maintain the stability of the solution. However, such salts may undesirably inhibit the polymerization of the furan derivative, such as 5-HMF and / or its derivatives, during subsequent heating. In other words, the desired polymerization during the modification treatment of wood materials may be inhibited. Inorganic substances that inhibit the polymerization of furan derivatives, such as 5-HMF and / or its derivatives, at room temperature but do not adversely inhibit the polymerization of furan derivatives, such as 5-HMF and / or its derivatives, after the furan derivative resinification solution, such as 5-HMF and / or its derivative resinification solution, has been impregnated into a wood material are limited to a certain extent, and may be, for example, inorganic substances that can be decomposed and gasified by heating and removed from the reaction system. Typical examples include inorganic salts such as ammonium carbonate and / or ammonium bicarbonate, and inorganic substances such as ammonia.

[0065] From the above perspective, the inorganic salt-containing inorganic substance in the furan derivative resinification solution, e.g., 5-HMF and / or its derivative resinification solution, used in the production method of the present invention is preferably an inorganic substance containing an inorganic salt that decomposes and gasifies upon heating. In other words, the "inorganic substance containing an inorganic salt that inhibits polymerization of the furan derivative at room temperature" contained in the furan derivative resinification solution, e.g., 5-HMF and / or its derivative resinification solution, may be an inorganic substance containing an inorganic salt that decomposes upon heating (more specifically, decomposes and gasifies upon heating) after the furan derivative resinification solution, e.g., 5-HMF and / or its derivative resinification solution, is impregnated into a wood material. From a similar perspective, the inorganic salt-containing inorganic substance in the furan derivative resinification solution, e.g., 5-HMF and / or its derivative resinification solution, used in the production method of the present invention is preferably excluding sodium hydroxide and potassium hydroxide. In other words, the "inorganic substance containing an inorganic salt that inhibits polymerization of a furan derivative at room temperature" contained in the furan derivative resinification solution, for example, the 5-HMF and / or its derivative resinification solution, is preferably an inorganic substance containing an inorganic salt excluding sodium hydroxide and potassium hydroxide.

[0066] The content of these inorganic salts may be adjusted as appropriate. Adjusting the content makes it easier to control the degree of polymerization and / or adhesion of the furan derivative, e.g., 5-HMF and / or its derivatives, to the wood material at a temperature of 5°C or higher after the wood material is impregnated with a furan derivative resinification solution, e.g., 5-HMF and / or its derivative resinification solution, and thus makes it easier to control the location in the wood material cells where the furan resin, e.g., 5-HMF and / or its derivative resin, is produced. For example, increasing the content of an "inorganic substance containing an inorganic salt that inhibits the polymerization of a furan derivative at room temperature" in the solution, e.g., an "inorganic substance containing an inorganic salt that inhibits the polymerization of 5-HMF and / or its derivatives at room temperature," makes it easier to control the degree of polymerization of the furan derivative, e.g., 5-HMF and / or its derivatives, to a low level, and makes it easier to produce a low-molecular-weight furan derivative resin in the cell walls. On the other hand, for example, by further reducing the content of the "inorganic substance containing an inorganic salt that inhibits the polymerization of a furan derivative at room temperature", e.g., the "inorganic substance containing an inorganic salt that inhibits the polymerization of 5-HMF and / or a derivative thereof at room temperature", it becomes easier to control the degree of polymerization of the furan derivative, e.g., 5-HMF and / or a derivative thereof, to a high level, and high-molecular-weight furan resin becomes more likely to be produced and accumulated in the cell lumen.

[0067] As described above, these inorganic substances containing inorganic salts as stabilizers can more effectively stabilize the state of a furan derivative resinification solution, such as a 5-HMF and / or its derivative resinification solution, before it is impregnated into wood by inhibiting the polymerization of furan derivatives, such as 5-HMF and / or its derivatives, at room temperature. Therefore, modification treatments using these inorganic substances can contribute to improving the properties of modified wood materials. Furthermore, this can reduce variation in the finished quality of modified wood materials, making it easier to standardize the quality of final products that use modified wood materials. In the present disclosure, "inorganic substances containing inorganic salts that inhibit the polymerization of furan derivatives at room temperature" or "inorganic substances containing inorganic salts that inhibit the polymerization of 5-HMF and / or its derivatives at room temperature" may also be referred to as stabilizers.

[0068] In the present invention, polymerization in solution may be appropriately considered to facilitate imparting desired properties to wood materials. For example, by way of example only, the molecular weight and reactivity of the polymer (resin) produced in the initial polymerization of the furan derivative may be controlled, and polymerization of the furan derivative in the furan derivative resinification solution in solution state may be suppressed, while the polymerization reaction in the wood material may be suitably promoted by heating after the furan derivative has penetrated the wood material.

[0069] In the furan derivative resinification solution, the concentration of the "inorganic substance containing an inorganic salt that inhibits polymerization of the furan derivative at room temperature" may be 0.01 mol or less, 0.005 mol or less, 0.004 mol or less, 0.003 mol or less, 0.002 mol or less, or 0.001 mol or less per mol of furan derivative in the solution (in this case, the lower limit may be greater than 0 mol). For example, the concentration or amount of the "inorganic substance containing an inorganic salt that inhibits polymerization of the furan derivative at room temperature" in the furan derivative resinification solution may be 0.0001 to 0.004 mol, e.g., 0.0003 to 0.003 mol, 0.0005 to 0.001 mol, 0.0006 to 0.001 mol, or 0.0007 to 0.0009 mol, per mol of furan derivative in the solution. Such a concentration or amount of the "inorganic substance containing an inorganic salt that inhibits polymerization of a furan derivative at room temperature" can facilitate more favorable modification of wood materials. For example, modification treatment of wood materials using the solution can more easily impart to the wood materials better dimensional stability and at least one favorable property selected from the group consisting of bending strength, compressive strength, and hardness.

[0070] The incorporation of such an inorganic salt-containing inorganic substance into the furan derivative resinification solution makes the furan derivative more stable in solution at room temperature, for example. In other words, even when the solution is stored for a relatively long period of time (e.g., when left at room temperature for a long period of time) or when stored in an environment above room temperature (e.g., when exposed to temperatures above room temperature), undesirable polymerization of the furan derivative (e.g., undesirable polymerization that can be understood as turbidity, insolubilization, and / or separation in the solution) is more easily suppressed, allowing the furan derivative resinification solution to be used in a more suitable state for modification treatment. Furthermore, such an "inorganic substance containing an inorganic salt that suppresses the polymerization of the furan derivative at room temperature" can more effectively stabilize the quality of the solution before it is impregnated into the wood material, due to the suppression of undesirable polymerization of the furan derivative, and more effectively suppress variation in the properties imparted to the wood material by treatment. For example, variation in anti-swelling capacity (ASE) and at least one property selected from the group consisting of bending strength, compressive strength, and hardness can be more effectively suppressed.

[0071] The "inorganic substance containing an inorganic salt that inhibits the polymerization of a furan derivative at room temperature" may be, for example, an inorganic carbonate. Additionally or alternatively, the "inorganic substance containing an inorganic salt that inhibits the polymerization of a furan derivative at room temperature" may be, for example, an ammonium salt. Furthermore, the "inorganic substance containing an inorganic salt that inhibits the polymerization of a furan derivative at room temperature" may be ammonia.

[0072] In a preferred embodiment, the "inorganic substance containing an inorganic salt that inhibits the polymerization of furan derivatives at room temperature" may be at least one inorganic salt selected from ammonium carbonate, ammonium bicarbonate, and the like. Briefly, the "inorganic substance containing an inorganic salt that inhibits the polymerization of furan derivatives at room temperature" may be, for example, ammonium carbonate, ammonium bicarbonate, or a combination of ammonium carbonate and ammonium bicarbonate. This is because it can inhibit the undesired polymerization of furan derivatives in solution at room temperature, thereby more appropriately maintaining the quality stability of the solution before impregnation into woody materials, and it can also be an inorganic salt that does not inhibit the polymerization of furan derivatives when heated after impregnation. Furthermore, in a preferred embodiment, the "inorganic substance containing an inorganic salt that inhibits the polymerization of furan derivatives at room temperature" may be ammonia. Briefly, the "inorganic substance containing an inorganic salt that inhibits the polymerization of furan derivatives at room temperature" may be, for example, ammonia, ammonium carbonate, ammonium bicarbonate, or a combination of two or three inorganic salts selected from the group consisting of ammonia, ammonium carbonate, and ammonium bicarbonate. This is because the undesirable polymerization of the furan derivative in the solution at room temperature can be suppressed, thereby more suitably maintaining the quality stability of the solution before it is impregnated into the wood material, and the inorganic substance can contain an inorganic salt that does not inhibit the polymerization of the furan derivative when heated after impregnation. Note that "suppressing polymerization" here means that the presence of such an inorganic salt reduces or stops the rate of the polymerization reaction compared to when it is not present (for example, when the polymerizable monomer is present alone).

[0073] The "inorganic salt that inhibits the polymerization of furan derivatives at room temperature" may be an inorganic salt that exhibits basicity in an aqueous solution (e.g., an aqueous solution at room temperature), such as an inorganic salt that renders the furan derivative resinification solution basic or shifts the pH of the solution to a more basic side (i.e., increases the pH). It is conceivable that adding a salt such as sodium hydroxide and / or potassium hydroxide to a furan derivative resinification solution consisting of a furan derivative, an inorganic salt that promotes the polymerization of the furan derivative, which is neutral to weakly acidic at room temperature, and water to maintain the basicity of the aqueous furan derivative resin solution would inhibit the polymerization of the furan derivative and maintain the stability of the solution. However, such salts would adversely inhibit the polymerization of the furan derivative upon subsequent heating. In other words, the desired polymerization during the modification treatment of wood materials could be inhibited. Salts that inhibit the polymerization of furan derivatives at room temperature but do not adversely inhibit the polymerization of the furan derivative after the furan derivative resinification solution has been infiltrated into the wood material are limited to a certain extent. For example, a salt that decomposes and gasifies upon heating and is removed from the reaction system may be used. Typical examples include inorganic salts such as ammonium carbonate and / or ammonium hydrogen carbonate.

[0074] From the above perspective, the inorganic salt in the furan derivative resinification solution used in the production method of the present invention is preferably an inorganic salt that decomposes and gasifies when heated. In other words, the "inorganic salt that inhibits the polymerization of the furan derivative at room temperature" contained in the furan derivative resinification solution may be an inorganic salt that decomposes when heated (more specifically, decomposes and gasifies when heated) after the furan derivative resinification solution has been impregnated into a woody material. From the same perspective, the inorganic salt in the furan derivative resinification solution used in the production method of the present invention preferably excludes sodium hydroxide and potassium hydroxide. In other words, the "inorganic salt that inhibits the polymerization of the furan derivative at room temperature" contained in the furan derivative resinification solution is preferably an inorganic salt excluding sodium hydroxide and potassium hydroxide.

[0075] The content of these inorganic salts may be adjusted as appropriate. Adjusting the content makes it easier to control the degree of polymerization of the furan derivatives caused by heating after the furan derivative resinification solution has been infiltrated into the wood material, and thus makes it easier to control the location of the wood material cells where the furan resin is produced. For example, increasing the content of the "inorganic salt that inhibits the polymerization of the furan derivatives at room temperature" in the solution makes it easier to control the degree of polymerization of the furan derivatives low, and makes it easier to produce low-molecular-weight furan derivative resins in the cell walls. On the other hand, decreasing the content of the "inorganic salt that inhibits the polymerization of the furan derivatives at room temperature" makes it easier to control the degree of polymerization of the furan derivatives high, and makes it easier to produce and accumulate high-molecular-weight furan resins in the cell cavities.

[0076] As mentioned above, these inorganic salts as stabilizers can inhibit the polymerization of the furan derivative at room temperature, thereby more favorably stabilizing the state of the furan derivative resinified solution before it is impregnated into wood, and therefore modification treatment using them can contribute to improving the properties of modified wood materials. Furthermore, this can reduce variation in the finished quality of the modified wood materials, making it easier to standardize the quality of final products that use the modified wood materials.

[0077] In the present invention, polymerization in solution may be appropriately considered to facilitate imparting desired properties to wood materials. For example, by way of example, the molecular weight and reactivity of the polymer (resin) produced in the initial polymerization of the furan derivative may be controlled, and the polymerization of the furan derivative in the furan derivative resinification solution at room temperature may be suppressed, while the polymerization reaction in the wood material may be suitably promoted by heating after the furan derivative has penetrated the wood material.

[0078] The concentration of the "inorganic salt that inhibits the polymerization of the furan derivative at room temperature" in the furan derivative resinification solution may be 0.01 mol or less, 0.005 mol or less, 0.004 mol or less, 0.003 mol or less, 0.002 mol or less, or 0.001 mol or less per mol of furan derivative in the solution (in this case, the lower limit may be greater than 0 mol). For example, the concentration or amount of the "inorganic salt that inhibits the polymerization of the furan derivative at room temperature" in the furan derivative resinification solution may be 0.0001 to 0.004 mol per mol of furan derivative in the solution, such as 0.0003 to 0.003 mol, 0.0005 to 0.001 mol, 0.0006 to 0.001 mol, or 0.0007 to 0.0009 mol, per mol of furan derivative in the solution. Such a concentration or amount of the "inorganic salt that inhibits the polymerization of the furan derivative at room temperature" can facilitate more favorable modification of woody materials. For example, modifying wood materials with the solution can help impart to the wood materials at least one preferred property selected from the group consisting of better anti-swelling capacity (ASE) and / or bending strength, compressive strength or hardness.

[0079] If desired, a stabilizer may be added to the furan derivative resinification solution for the purpose of stabilizing the furan derivative in the solvent during long-term storage at room temperature or storage under harsh environments such as low temperatures. Prior to the heating step (step 2), the wood material may be subjected to a heating treatment at a temperature lower than the heating temperature. In other words, during the heating treatment, the "wood material permeated with the solution" may be subjected to a certain "initial setting temperature." By subjecting the wood material to this "initial setting temperature" (i.e., heating treatment at this initial setting temperature), at least a portion of the stabilizer in the furan derivative resinification solution may be decomposed in the wood material permeated with the solution. For example, by subjecting the wood material to the "initial setting temperature," it is possible to decompose at least a portion of the stabilizer in the furan derivative resinification solution while minimizing evaporation of the solution, thereby promoting more favorable modification of the wood material. In other words, by modifying wood materials using a solution, it becomes easier to impart to the wood materials more favorable anti-swelling ability (ASE) and at least one property selected from the group consisting of bending strength, compressive strength and hardness.

[0080] The heating treatment at the "initial setting temperature" may be performed by, for example, heating the wood material impregnated with the solution in a furan derivative resinification solution, so as to minimize evaporation of the impregnated solution. For example, the initial setting temperature treatment may involve not directly raising the temperature to the desired heating temperature in step 2), but instead maintaining a lower temperature (as will be described later) for a certain period of time (this can also be considered as a step-like change in temperature over time). As just one example, the heating treatment at the "initial setting temperature" may involve heating the wood material impregnated with the solution in a furan derivative resinification solution, so as to minimize evaporation of the impregnated solution, thereby decomposing at least a portion or all of the stabilizer (i.e., an inorganic salt that inhibits polymerization of the furan derivative at room temperature) that may be optionally contained in the furan derivative resinification solution.

[0081] The initial setting temperature may be lower than the heating temperature in step 2). For example, the initial setting temperature may be a temperature equivalent to 80% of the heating temperature in step 2) or a temperature lower than that (i.e., the upper limit of the initial setting temperature may be a temperature equivalent to 80% of the heating temperature), and the lower limit may be a temperature equivalent to 20% of the heating temperature in step 2). In other words, the initial setting temperature may be T ｉ and the heating temperature T ｉｉ Then, T ｉ = 0.2T ｉｉ ~0.9T ｉｉ For example, T ｉ = 0.3T ｉｉ ~0.9T ｉｉ , 0.4T ｉｉ ~0.75T ｉｉ , 0.35T ｉｉ ~0.7T ｉｉ、 or 0.4T ｉｉ ~0.7T ｉｉ Or, T ｉ = 0.2T ｉｉ ~0.6T ｉｉ , T ｉ = 0.3T ｉｉ ~0.6T ｉｉ、 T ｉ = 0.3Tｉｉ ~0.5T ｉｉ etc. may also be used.

[0082] By way of example only, the initial setting temperature (e.g., the chamber temperature condition set as the initial setting temperature) may be 50 to 100° C., such as 50 to 90° C., 50 to 85° C., 55 to 85° C., or 55 to 80° C. The time for which the wood material is subjected to such treatment at the initial setting temperature may typically be 1 to 120 hours, such as 4 to 72 hours, 6 to 60 hours, 10 to 60 hours, 20 to 60 hours, 35 to 60 hours, or 40 to 60 hours.

[0083] As an example of an embodiment of the treatment at the initial set temperature, the production method of the present invention may further include, between step 1) and step 2), temporarily heating the wood material impregnated with the furan derivative resinifying solution to, for example, 50 to 100°C, 50 to 90°C, 50 to 85°C, 55 to 85°C, 55 to 80°C, or 50 to 70°C.

[0084] In a preferred embodiment, a production method using a furan derivative resinification solution containing 5-HMF as the furan derivative does not subject the "wood material permeated with the solution" to the above-mentioned "initial setting temperature." For example, when using a furan derivative resinification solution such as a 5-HMF resinification solution, the furan derivative resinification solution such as a 5-HMF resinification solution that has permeated the wood material may be subjected to the desired heating (i.e., the heating temperature of step 2)) without undergoing the "initial setting temperature" treatment. In production using a furan derivative resinification solution such as a 5-HMF resinification solution, it can be said that the desired modified wood material can be obtained without being subjected to the "initial setting temperature." In this regard, a production method using a furan derivative resinification solution containing 5-HMF as the furan derivative makes it easier to impart a suitable anti-swelling ability (ASE) and at least one property selected from the group consisting of bending strength, compressive strength, and hardness, even without being subjected to the initial setting temperature in the production process. As an example, after a wood material is impregnated with a 5-HMF resinification solution containing 5-HMF and / or a derivative thereof and an inorganic salt that promotes its polymerization, the heating in step 2) may be carried out without carrying out a treatment of maintaining the temperature at a lower temperature than the desired heating temperature in step 2) (for example, without maintaining the lower temperature for the period of time during which the wood material is subjected to the treatment at the initial setting temperature).

[0085] [Solution of the Present Invention] The solution of the present invention is a furan derivative resinification solution suitable for use in the above-mentioned production method. That is, the solution of the present invention is a solution for modifying wood materials, and is a furan derivative resinification solution comprising a furan derivative and an agent that promotes polymerization and / or adhesion of at least a portion of the furan derivative to the wood material. If desired, the furan derivative resinification solution may contain an inorganic salt that inhibits polymerization of the furan derivative at room temperature in order to further enhance the stability of the furan derivative in the solution.

[0086] As described above, such a solution preferably contains one or two salts as solute components other than the furan derivative. In other words, the furan derivative resinification solution of the present invention contains an "inorganic salt that promotes the polymerization of the furan derivative and / or its adhesion to wood materials" and, if desired, may further contain an "inorganic salt that inhibits the polymerization of the furan derivative at room temperature." This solution makes it a more suitable modification treatment solution for wood materials. For example, by using the solution of the present invention in the modification treatment of wood materials, it is possible to impart to the wood materials more suitable anti-swelling ability (ASE) and at least one property selected from the group consisting of bending strength, compressive strength, and hardness.

[0087] In a preferred embodiment, the concentration of the "inorganic salt that promotes the polymerization of a furan derivative and / or its adhesion to a woody material" in the solution of the present invention may be 0.001 to 0.1 mol per 1 mol of the furan derivative in the solution. The concentration of the "inorganic salt that inhibits the polymerization of 5-MHF at room temperature," which can be optionally contained, may be 0.0001 to 0.004 mol per 1 mol of the furan derivative in the solution.

[0088] In a preferred embodiment, the content or concentration of the "inorganic substance containing an inorganic salt that inhibits the polymerization of a furan derivative at room temperature," which may be optionally contained in the solution of the present invention, may be less than or lower than the content or concentration of the "inorganic salt that promotes the polymerization of a furan derivative and / or its adhesion to a wood material." More specifically, in a furan derivative resinification solution, the molar amount of the "inorganic substance containing an inorganic salt that inhibits the polymerization of a furan derivative at room temperature" per mol of furan derivative in the solution may be less than the molar amount of the "inorganic salt that promotes the polymerization of a furan derivative and / or its adhesion to a wood material" per mol of furan derivative in the solution. Such a relative relationship between the contents of the two inorganic salts tends to result in a more suitable modification treatment solution, which, when used in the modification treatment of a wood material, tends to impart to the wood material more suitable anti-swelling ability (ASE) and at least one property selected from the group consisting of bending strength, compressive strength, and hardness.

[0089] The furan derivative resinification solution of the present invention is preferably characterized at least by its high stability. Therefore, even when the solution is stored for a relatively long period of time or under harsh conditions (e.g., when a long time is required between the preparation of the solution and its use, as would be expected in actual production, or when the solution is stored in an environment with drastic temperature changes), the undesired polymerization of the furan derivative is more likely to be suppressed, allowing the furan derivative resinification solution to be used in a more suitable state for modification treatment. For example, the furan derivative resinification solution of the present invention does not become cloudy, insolubilized, and / or separated, even after 7 days (more preferably 14 days, and even more preferably 1 month) at room temperature after its preparation (i.e., the solution does not become cloudy, insolubilized, and / or separated at least immediately after the 7 or 14 days have passed. For example, it can be determined that the solution does not become cloudy, insolubilized, and / or separated, at least visually).

[0090] A furan derivative resinified solution with relatively high stability is particularly advantageous from the viewpoint of industrial or practical processing and manufacturing. This is because it can more effectively suppress the variability in the properties of the resulting modified wood material, even when the modified wood material is mass-produced. For example, it can help avoid large variations in anti-swelling capacity (ASE), flexural strength, compressive strength, and hardness between batches, which can make it difficult to market the product.

[0091] Further details, specific embodiments, and other matters regarding the furan derivative resinified solution of the present invention are explained in the above section [Production method of the present invention], and therefore will not be explained here to avoid duplication.

[0092] [Modified Wood Material of the Present Invention] The modified wood material of the present invention is a wood material obtained by the above-mentioned production method. That is, the modified wood material of the present invention is a wood material modified by the above-mentioned production method and containing at least a polymerized or attached furan derivative.

[0093] More specifically, the modified wood material of the present invention is a wood material modified using a "furan derivative resinification solution containing a furan derivative and an inorganic salt that promotes the polymerization of the furan derivative and / or its adhesion to the wood material." Therefore, the modified wood material comprises at least a furan resin formed by polymerization of the furan derivative or a furan derivative adhered to the wood material, and in some preferred cases, may also contain substances derived from the inorganic salt used as a raw material. The resin formed by polymerization is not necessarily limited to those in the polymer category, but may at least partially contain those in the oligomer category. Furthermore, when the modified wood material is modified using a furan derivative resinification solution that optionally further contains an "inorganic substance containing an inorganic salt that inhibits the polymerization of the furan derivative at room temperature," in addition to the aforementioned substances, the modified wood material may also contain an "inorganic substance containing an inorganic salt that inhibits the polymerization of the furan derivative at room temperature" or a substance derived therefrom.

[0094] In a preferred embodiment, the modified wood material of the present invention may exhibit at least one of the following physical properties: (Anti-swelling capacity / ASE) Anti-swelling capacity (ASE) of 50% or more, e.g., 50-95, 50-80, 50-70, 50-65, or 50-60%. Anti-swelling capacity (ASE) (%) = [(S ｃ -S ｔ ) / S ｃ ]×100...Formula (3) (In the formula, S ｔ is the surface swelling rate (%) of the modified material when it is allowed to absorb moisture or water under certain conditions from a completely dry state, and S ｃ is the end grain area swelling rate (%) of the unmodified material (or unmodified wood material) when it is subjected to moisture or water absorption under constant conditions from a completely dry state under the same conditions as the modified wood. The anti-swelling ability (ASE) is an indicator of dimensional stability. An ASE of 50% or more is preferable for practical use of modified wood materials, while an ASE of less than 50% is unsuitable for practical use. In this specification, "completely dry" / "completely dry state" refers to the state of the material when the weight of the modified or unmodified material is no longer changed when placed in an incubator (manufactured by Yamato Scientific Co., Ltd., model DN43) set at 105°C. Furthermore, the total dry weight is the weight of the material when the weight change no longer occurs.

[0095] (Bending strength) Bending strength is the maximum stress value obtained when a bending test is conducted in accordance with "JIS Z 2101 Testing Methods for Wood," i.e., the maximum stress value obtained when a bending test is conducted using a testing machine capable of recording load and displacement (e.g., Shimadzu Autograph, EZ TEST) with a "central load method" in which a load is applied to the center between supports. The bending strength is the maximum stress value obtained when a bending test is conducted in accordance with "JIS Z 2101 Testing Methods for Wood," with a "central load method" in which a load is applied to the center between supports using a testing machine capable of recording load and displacement (e.g., Shimadzu Autograph, EZ TEST). ... using a testing machine capable of recording load and displacement (e.g., Shimadzu Autograph, EZ TEST) with a "central load method" in which a load is applied to the center between supports. The bending strength is the maximum stress value obtained when a bending test is conducted using a testing machine capable of recording load and displacement (e.g., Shimadzu Autograph, EZ TEST) with a "central load method" in which a load is applied to the center between supports. The bending strength is the maximum stress value obtained when a bending test is conducted using a testing machine capable of recording load and displacement (e.g., Shimadzu Autograph, EZ TEST). The bending strength is the maximum stress value obtained when a bending test is conducted using a testing machine capable of recording load and displacement using a "central load method" in which a load is applied to the center between supports. The bending strength is the maximum stress value obtained when a bending test is conducted using a testing machine capable of recording load and displacement using a "central load method" in which a load

[0096] A production method using a furan derivative resinified solution containing 5-HMF as a furan derivative makes it easier to impart suitable anti-swelling ability (ASE) and at least one property selected from the group consisting of flexural strength, compressive strength, and hardness in the production process.

[0097] In a preferred embodiment, the modified wood material of the present invention may be a wood material used for flooring, decking (e.g., wood decking), exterior wall materials, louvers, furniture, truck bodies, wooden fences, guardrails, exterior construction materials, and / or musical instruments.

[0098] The modified wood material of the present invention can have the above-mentioned preferable properties and can be used not only for indoor purposes but also for outdoor purposes. Therefore, the present invention can be said to contribute to providing new uses and added value to coniferous trees (e.g., domestic coniferous trees).

[0099] Further specific aspects and other specific matters regarding the modified wood material of the present invention have been directly or indirectly explained in the above-mentioned [Manufacturing method of the present invention] and [Solution of the present invention], so explanations here will be omitted to avoid duplication.

[0100] Although one embodiment of the present invention has been described above, it is merely a typical example. Therefore, it will be readily apparent to those skilled in the art that the present invention is not limited to the described embodiment, and various other aspects and modifications are possible.

[0101] For example, the effects described in the present specification are merely illustrative and are not necessarily limited to these effects, and additional effects may also be present. Furthermore, for example, the furan derivative resinification solution described in relation to the present invention contains a furan derivative and an inorganic salt that promotes polymerization of the furan derivative, but the presence of components that may be unavoidably or accidentally mixed in during preparation, storage, and / or use of the solution (for example, components present in trace or extremely trace amounts, or components that would be recognized as trace or extremely trace amounts by those skilled in the art) is acceptable.

[0102] It should be noted that the above-described present invention can also include the following aspects. - First Aspect: A method for producing a modified wood material, comprising the steps of: 1) impregnating a wood material with a 5-HMF resinification solution containing 5-hydroxymethylfurfural (5-HMF) and an inorganic salt and / or a hydrate or anhydride thereof, and / or an organic acid and / or an anhydride or salt thereof, which promotes polymerization and / or adhesion of at least a portion of the 5-HMF to the wood material, and 2) polymerizing at least a portion of the 5-HMF in the impregnated 5-HMF resinification solution within the wood material and / or adhering to the wood material. - Second Aspect: A production method according to the first aspect, in which the solvent in the 5-HMF resinification solution is an aqueous medium. Aspect 3: The method according to any one of Aspects 1 or 2, wherein the inorganic salt that promotes at least a portion of the polymerization of 5-HMF and / or its adhesion to the wood material is an inorganic salt consisting of an anion of a chloride ion and / or a sulfate ion and a cation of an ammonium ion, a magnesium ion and / or a hydrogen ion. Aspect 4: The method according to any one of Aspects 1 to 3, wherein the concentration of the inorganic salt that promotes the polymerization of 5-HMF and / or its adhesion to the wood material is 0.001 to 0.1 mol per 1 mol of 5-HMF.Fifth Aspect: The method according to either the first or second aspect, wherein the organic acid and / or anhydride / salt that can be formed thereby that promotes at least partial polymerization of 5-HMF and / or adhesion to the wood material is one or more selected from the group consisting of one or more organic acids and / or anhydrides / salts that can be formed thereby, selected from the group consisting of saturated or unsaturated aliphatic hydrocarbons having 1 to 20, 1 to 6, or 1 to 4 carbon atoms and having one or more carboxyl and / or sulfo groups substituted with at least one functional group selected from the group consisting of hydrogen, halogen, alkyl, formyl, hydroxyl, and hydroxyalkyl groups, and saturated or unsaturated aromatic hydrocarbons having 3 to 20, 3 to 18, or 6 to 12 carbon atoms and having one or more carboxy and / or sulfo groups substituted with at least one functional group selected from the group consisting of hydrogen, halogen, alkyl, formyl, hydroxyl, and hydroxyalkyl groups. - Sixth aspect: The production method according to the fifth aspect, wherein the concentration of the organic acid and / or the anhydride / salt that can be formed thereby that promotes the polymerization of 5-HMF and / or its adhesion to the wood material is 0.001 to 0.1 mol per 1 mol of 5-HMF. - Seventh aspect: The production method according to any one of the first to sixth aspects, wherein step 1) is carried out under reduced pressure that is less than atmospheric pressure. - Eighth aspect: The production method according to any one of the first to seventh aspects, wherein step 2) is carried out at 5 to 180°C. - Ninth aspect: The production method according to any one of the first to eighth aspects, wherein the wood material is a softwood. - Tenth aspect: The production method according to any one of the first to 9th aspects, wherein the wood material is a cedar or cypress. - Eleventh Aspect: The manufacturing method according to any one of the first to tenth aspects, wherein the concentration of 5-HMF in the 5-HMF resinification solution is 5 to 50% by weight (excluding 50% by weight) based on the total weight of the 5-HMF resinification solution. - Twelfth Aspect: A 5-HMF resinification solution for modifying wood materials, comprising 5-HMF and an inorganic salt that promotes polymerization of 5-HMF in the wood material and / or adhesion of 5-HMF to the wood material. - Thirteenth Aspect: The 5-HMF resinification solution according to the twelfth aspect, wherein the solvent in the 5-HMF resinification solution is an aqueous medium.A fourteenth aspect: A wood material modified by the manufacturing method according to any one of claims 1 to 11, the modified wood material comprising at least polymerized 5-HMF. A fifteenth aspect: The modified wood material according to the fourteenth aspect, which is a wood material used for flooring, decking, exterior wall materials, louvers, furniture, truck bodies, wooden fences, guardrails, exterior construction materials, and / or musical instruments.

[0103] [Accelerator Study] Cryptomeria japonica rectangular sapwood (30 mm x 30 mm x 5 mm) was immersed in a 5-HMF resinification solution containing 30 wt% 5-HMF, 0.01 mol of various accelerators per 1 mol of 5-HMF, and water at room temperature under a reduced pressure of 50 hPa or less for 2 hours, and then returned to normal pressure and immersed in the resinification solution for 24 hours. The cedar rectangular sapwood was then removed from the 5-HMF resinification solution and dried and reacted at atmospheric pressure for 3 hours at 80°C and then for 8 hours at 105°C to prepare 5-HMF resinified samples. The calculated anti-swelling capacity (ASE) of the 5-HMF resinified samples prepared using various accelerators is shown in Table 1.

[0104] The results in Table 1 clearly demonstrate that various inorganic salts and their hydrates, as well as organic acids, promote the resinification of 5-HMF in wood materials and impart significantly superior anti-swelling properties to the wood materials. Specifically, inorganic salts selected from the group consisting of ammonium chloride, magnesium chloride hexahydrate, ammonium sulfate, and ammonium hydrogen sulfate, as well as organic acids selected from the group consisting of maleic acid and citric acid, are shown to promote at least partial polymerization of 5-HMF and / or adhesion to the wood materials, thereby imparting anti-swelling properties to the wood materials.

[0105] [Study on 5-HMF Concentration] Cuboid sapwood (30 mm x 30 mm x 5 mm) of Japanese cedar and Japanese cypress was immersed in a 5-HMF resinification solution containing 5 to 30 wt% 5-HMF, 0.01 mol of ammonium hydrogen sulfate per 1 mol of 5-HMF, and water at room temperature under a reduced pressure of 50 hPa or less for 2 hours, and then returned to normal pressure and immersed in the resinification solution for 24 hours. The cedar rectangular sapwood was then removed from the 5-HMF resinification solution and dried and reacted at atmospheric pressure for 3 hours at 80°C and then at 105°C for 8 hours to prepare 5-HMF resinification samples. The anti-swelling capacity (ASE) calculated for 5-HMF resinification samples prepared using 5-HMF resinification solutions of various concentrations is shown in Table 2.

[0106] The results in Table 2 show that a 5-HMF concentration in the resinification solution in the range of 5 to 50% by weight promotes resinification of wood materials and imparts remarkably excellent anti-swelling properties to the wood materials.

[0107] [Reaction Temperature Study 1] Cuboid sapwood (30 mm x 30 mm x 5 mm) of Japanese cedar and Japanese cypress was immersed in a 5-HMF resinification solution containing 20% ​​by weight of 5-HMF, 0.01 mol of ammonium hydrogen sulfate per 1 mol of 5-HMF, and water at room temperature under a reduced pressure of 50 hPa or less for 2 hours, and then returned to normal pressure and immersed in the resinification solution for 24 hours. The cedar rectangular sapwood was then removed from the 5-HMF resinification solution and dried and reacted at atmospheric pressure for 3 hours at 80°C and 8 hours at 105°C to prepare 5-HMF resinified samples. The anti-swelling capacity (ASE) calculated for the 5-HMF resinified samples prepared at various reaction temperatures is shown in Table 3.

[0108] The results in Table 3 demonstrate that resinification of wood materials is promoted at a reaction temperature range of at least 80 to 140°C, imparting significantly superior anti-swelling properties to the wood materials. Furthermore, the lower the reaction temperature, the higher the anti-swelling properties (ASE) of the 5-HMF resinified samples tends to be, indicating that resinification of wood materials using 5-HMF can achieve its objectives even at lower reaction temperatures. Furthermore, although it has been shown that significantly superior anti-swelling properties are imparted to wood materials even at high reaction temperatures, it is preferable to set the reaction temperature at 180°C or below for safety reasons.

[0109] [Reaction Temperature Study 2] Since a trend was shown where the lower the reaction temperature, the higher the anti-swelling capacity (ASE) was, the anti-swelling capacity (ASE) of 5-HMF resinified samples was calculated under the same conditions as in [Reaction Temperature Study 1], except that the reaction temperature was set at 20°C and cedar rectangular sapwood was used. The anti-swelling capacity (ASE) calculated for the 5-HMF resinified samples prepared by reaction at 20°C is shown in Table 4.

[0110] The results in Table 4 show that resinification of wood materials is promoted even at a reaction temperature of 20°C, and that the wood materials are endowed with significantly superior anti-swelling ability. In addition, the lower the reaction temperature, the higher the anti-swelling ability (ASE) was, indicating that the objective can be achieved at a reaction temperature within the range in which the 5-HMF resinification solution does not freeze, for example, at a reaction temperature of 5°C or higher. These results are

[0111] The technology according to the present invention can be used to modify wood materials. For example, modifying wood materials can make them more suitable for outdoor use. Therefore, the present invention can be suitably used not only for interior materials such as furniture and flooring, but also for exterior materials such as wood decks, particularly for wood materials used outdoors.

Claims

1. A method for producing a modified wood material, comprising the steps of: 1) impregnating a wood material with a 5-HMF resinification solution containing 5-hydroxymethylfurfural (5-HMF) and inorganic salts and / or hydrates or anhydrides thereof and / or organic acids and / or anhydrides and salts thereof which promote at least a portion of the polymerization and / or adhesion of 5-HMF to the wood material; and 2) A step of polymerizing at least a portion of the 5-HMF in the permeated 5-HMF resinification solution in the wood material and / or attaching it to the wood material. The manufacturing method comprising:

2. The method according to claim 1, wherein the solvent in the 5-HMF resinification solution is an aqueous medium.

3. 3. The method according to claim 1, wherein the inorganic salt that promotes at least a portion of the polymerization of 5-HMF and / or its adhesion to the wood material is an inorganic salt having an anion of a chloride ion and / or a sulfate ion and a cation of an ammonium ion, a magnesium ion and / or a hydrogen ion.

4. 3. The method according to claim 1, wherein the concentration of the inorganic salt that promotes the polymerization of 5-HMF and / or its adhesion to the wood material is 0.001 to 0.1 mol per 1 mol of 5-HMF.

5. 3. The method according to claim 1, wherein the organic acid and / or anhydride / salt which can be formed by the organic acid promoting at least a portion of the polymerization of 5-HMF and / or its attachment to the wood material is one or more selected from the group consisting of saturated or unsaturated aliphatic hydrocarbons having 1 to 20, 1 to 6, or 1 to 4 carbon atoms and having one or more carboxyl and / or sulfo groups substituted with at least one functional group selected from the group consisting of hydrogen, halogen, alkyl, formyl, hydroxyl, and hydroxyalkyl groups, and saturated or unsaturated aromatic hydrocarbons having 3 to 20, 3 to 18, or 6 to 12 carbon atoms and having one or more carboxyl and / or sulfo groups substituted with at least one functional group selected from the group consisting of hydrogen, halogen, alkyl, formyl, hydroxyl, and hydroxyalkyl groups.

6. The method according to claim 5, wherein the concentration of the organic acid and / or the anhydride or salt which can be formed by the organic acid that promotes the polymerization of 5-HMF and / or the adhesion to the wood material is 0.001 to 0.1 mol per 1 mol of 5-HMF.

7. The method according to claim 1 or 2, wherein step 1) is carried out under reduced pressure below atmospheric pressure.

8. The method according to claim 1 or 2, wherein step 2) is carried out at 5 to 180° C.

9. 3. The method according to claim 1, wherein the wood material is a softwood.

10. 3. The method according to claim 1, wherein the wood material is cedar or cypress.

11. 3. The method according to claim 1, wherein the concentration of 5-HMF in the 5-HMF resinification solution is 5 to 50% by weight (excluding 50% by weight) based on the total weight of the 5-HMF resinification solution.

12. 5-HMF resinification solution for modifying wood materials, comprising: A 5-HMF resinification solution comprising 5-HMF and an inorganic salt that promotes polymerization of 5-HMF in and / or attachment to wood materials.

13. The 5-HMF resinification solution according to claim 12, wherein the solvent in the 5-HMF resinification solution is an aqueous medium.

14. 3. A wood material modified by the method according to claim 1 or 2, which comprises at least polymerized 5-HMF.

15. The modified wood material according to claim 14, wherein the wood material is a wood material used for flooring, decking, exterior wall materials, louvers, furniture, truck bodies, wooden fences, guardrails, exterior construction materials and / or musical instruments.