Method for producing modified wooden material, furan derivative resinification solution containing polyalcohol, 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, the method including: 1) a step for causing permeation, into a wooden material, of a furan derivative resinification solution containing a furan derivative, a polyalcohol, and an inorganic salt that promotes polymerization of the furan derivative; and 2) a step for polymerizing the furan derivative of the permeated furan derivative resinification solution in the wooden material by means of heating.

Description

Method for producing modified wood material, furan derivative resinizing solution containing polyhydric alcohol, 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 a furan derivative resinification solution, which is a combination of a furan derivative, a polyhydric alcohol, and an inorganic salt that promotes polymerization of the furan derivative, as a solution for modifying wood materials, and have thus completed the present invention.

[0007] The present invention provides a method for producing a modified wood material, comprising: 1) a step of impregnating a wood material with a furan derivative resinification solution containing a furan derivative such as furfuryl alcohol, a polyhydric alcohol such as polyethylene glycol, and an inorganic salt that promotes polymerization of the furan derivative; and 2) a step of polymerizing the furan derivative in the impregnated furan derivative resinification solution within the wood material by heating.

[0008] The present invention also provides a furan derivative resinification solution, such as a furfuryl alcohol resinification solution, containing a polyhydric alcohol such as polyethylene glycol, which is suitable for use in the above-mentioned production method. Specifically, the present invention provides a furan derivative resinification solution for modifying wood materials, which comprises a furan derivative such as furfuryl alcohol, a polyhydric alcohol such as polyethylene glycol, and an agent for accelerating the polymerization of the furan derivative such as a specific inorganic salt.

[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 furan derivative such as polymerized furfuryl alcohol and a polyhydric alcohol such as polyethylene glycol.

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

[0011] More specifically, a furan derivative resinization solution such as a furfuryl alcohol resinization solution used for modification can impart at least properties such as better anti-swelling ability (ASE) to a wood material by modifying the wood material with the solution, and can also exhibit a high yield when used in a method for producing a modified wood material.

[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 and the like 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 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 the like 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). In the invention of the previous application, the heating step for polymerizing the furan derivative caused low-boiling-point furan derivative monomers to evaporate and disperse from the wood, reducing yield. Therefore, a heating step was required in which the furan derivative monomers impregnated into the wood material were first heated at a relatively low temperature to partially polymerize the material to a certain extent while suppressing evaporation, and then heated at a high temperature to complete the polymerization. While partial polymerization of the furan derivative at a higher temperature could increase the yield of the raw material components used, it also had the problem of reducing the dimensional stability of the modified wood material.

[0018] The present disclosure attempts to solve the problems of yield of components used in the manufacturing method of modified wood materials and the problem of high dimensional stability required for, for example, exterior construction materials, by modifying the wood materials through resinification using a furan derivative and a polyhydric alcohol.

[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 manufacturing method of the present invention is a method for manufacturing a modified wood material, and comprises the steps of: 1) impregnating a wood material with a furan derivative resinification solution containing a furan derivative, a polyhydric alcohol, and an inorganic salt that promotes polymerization of the furan derivative; and 2) polymerizing the furan derivative of the impregnated furan derivative resinification solution in the wood material by heating.

[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 partial region 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 is incorporated into the wood material. In the following description, the "furan derivative resinification solution" will also be referred to simply as "solution."

[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, the term "heating" in the present disclosure refers to an artificial increase in temperature to favorably promote polymerization of the furan derivative, and refers to heating the wood material impregnated with the furan derivative resinification solution or its surrounding environment to a temperature condition of, for example, 65 to 160°C, 65 to 150°C, 65 to 130°C, or 65 to 105°C, or a temperature condition of 80 to 160°C, such as, for example, 75 to 150°C, 75 to 130°C, or 75 to 105°C, or a temperature condition of, for example, 80 to 150°C, 80 to 130°C, or 80 to 105°C. Note that, although the term "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 apparatus used in production (for example, the temperature set by the heating / warming means of the chamber). In the present disclosure, such heating may be continued for 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, such heating more suitably promotes polymerization of the furan derivative that has impregnated the wood material, and the wood material wet with the furan derivative resinification solution is dried.

[0024] The furan derivative resinification solution of the present disclosure contains a polyhydric alcohol. When combined with a furan derivative, the polyhydric alcohol increases the heating temperature for partial polymerization of the furan derivative in the method for producing a modified wood material, thereby increasing the yield of the components used and contributing to the modified wood material by inhibiting cracking / fracture and / or deformation / sagging and inhibiting a decrease in dimensional stability (ASE). In particular, when combined with a furan derivative, the polyhydric alcohol of the present disclosure increases the heating temperature for partial polymerization of the furan derivative in the method for producing a modified wood material, thereby contributing to the modified wood material by inhibiting a decrease in dimensional stability (ASE). The term "cracks" as used herein refers to cracks / fractures that occur in the modified wood material, such as cracks / fractures that occur during the polymerization of the furan derivative impregnated into the wood material by heating and / or cracks / fractures that occur after the polymerization of the furan derivative by heating. Furthermore, "deformation / sagging" refers to deformation / sagging such as warping, denting, and / or distortion that occurs in the modified wood material, and refers to, for example, deformation / sagging such as warping, denting, and / or distortion that occurs while the furan derivative that has been impregnated into the wood material is polymerized by heating, and / or deformation / sagging such as warping, denting, and / or distortion that occurs after the furan derivative is polymerized by heating.

[0025] The "inorganic salt that promotes the polymerization of a furan derivative" in the present disclosure acts to promote the polymerization of a furan derivative during, for example, resinification of a woody material accompanied by heating. Therefore, in the following description of the present specification, the "inorganic salt that promotes the polymerization of a furan derivative" is sometimes referred to simply as an "accelerator."

[0026] The furan derivative resinification solution of the present disclosure may contain, if desired, an "inorganic substance containing an inorganic salt that inhibits the polymerization of the furan derivative" in addition to an "inorganic salt that promotes the polymerization of the furan derivative at room temperature." That is, if desired, the furan derivative resinification solution of the present disclosure may contain an "inorganic salt that promotes the polymerization of the furan derivative at room temperature" and an "inorganic substance containing an inorganic salt that inhibits the polymerization of the furan derivative."

[0027] Depending on the type of furan derivative used, the furan derivative resinification solution in the present disclosure may optionally contain an "inorganic substance containing an inorganic salt that inhibits the polymerization of the furan derivative at room temperature." The "inorganic substance containing an inorganic salt that inhibits the polymerization of the furan derivative at room temperature" contributes to stabilizing the furan derivative resinification solution at room temperature. Therefore, in the following specification, the "inorganic substance containing an inorganic salt that inhibits the polymerization of the furan derivative at room temperature" is sometimes referred to as a "stabilizer." For example, when furfuryl alcohol is used as the furan derivative, adding an "inorganic substance containing an inorganic salt that inhibits the polymerization of the furan derivative at room temperature" to the furan derivative resinification solution can stabilize the furfuryl alcohol in the furan derivative resinification solution, thereby contributing to improving the properties of modified wood materials through modification treatment. Furthermore, this can reduce variation in the finished quality of modified wood materials, making it easier to standardize the quality of final products using the modified wood materials. On the other hand, when a furan derivative that can exist stably in a solvent at room temperature, such as 5-hydroxymethylfurfural (5-HMF), is contained in the furan derivative resinification solution, it may not be necessary to contain an "inorganic substance containing an inorganic salt that inhibits polymerization of the furan derivative at room temperature" in the furan derivative resinification solution.

[0028] 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.

[0029] 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.

[0030] The furan derivative used in the production method of the present invention may be at least one polymerizable monomer selected from the group consisting of, for example, furfuryl alcohol, furfural, and 5-hydroxymethylfurfural (5-HMF). For example, the furan derivative may be commercially available. As merely an example, furfuryl alcohol may be commercially available under the trade name "Furfuryl Alcohol" from Fujifilm Wako Pure Chemical Industries, Ltd., and 5-HMF may be commercially available under the trade name "5-HMF" from Combi-Blocks. These polymerizable monomers are more effectively inhibited from polymerization at room temperature by the action of an optional stabilizer in a solution containing a solvent (a solution containing 100% water by weight), making them more stable. After impregnation into wood materials, condensation polymerization is promoted by the action of an accelerator under heating, making it easier to resinify the wood materials.

[0031] Among furan derivatives, for example, furfuryl alcohol and 5-HMF tend to increase the anti-swelling capacity (ASE) of modified wood. In a preferred embodiment, the ASE can be 50% or more, for example, 50 to 95%, or 50 to 90%.

[0032] The polyhydric alcohol used in the production method of the present invention is not particularly limited, and may be, for example, an alkylene glycol having 2 to 10 carbon atoms or a polyalkylene glycol obtained by polymerizing an alkylene glycol having 2 to 10 carbon atoms, or, for example, an alkylene glycol having 2 to 6 carbon atoms or a polyalkylene glycol obtained by polymerizing an alkylene glycol having 2 to 6 carbon atoms. Here, the polyalkylene glycol may be a polymer obtained by polymerizing two or more alkylene glycols having 2 to 10 carbon atoms. In a preferred embodiment, the polyhydric alcohol may be one or a combination of two or more polyalkylene glycols selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, or glycerin, or polymers thereof such as diethylene glycol, dipropylene glycol, dibutylene glycol, triethylene glycol, tripropylene glycol, or tributylene glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, or polyglycerin. In a preferred embodiment, the polyhydric alcohol may have a molecular weight of 100 to 10,000, e.g., a molecular weight of 100 to 5,000, 100 to 1,000, 150 to 700, and / or 150 to 500. For example, the polyhydric alcohol may be commercially available.These are just a few examples, but ethylene glycol is available under the trade name "Ethylene Glycol" from Mitsubishi Chemical Corporation, propylene glycol is a general industrial product available from AGC Inc., butylene glycol is available under the trade name "1,3-BG" from Daicel Corporation, glycerin is available under the trade name "Glycerin" from NOF Corporation, diethylene glycol is available under the trade name "Diethylene Glycol" from Mitsubishi Chemical Corporation, dipropylene glycol is available under the trade name "Dipropylene Glycol" from ADEKA Corporation, and Djibutane Examples of ethylene glycol that can be used include those commercially available from KH Neochem Co., Ltd. under the trade name "1,3-butylene glycol-P"; those commercially available from Mitsubishi Chemical Corporation under the trade name "triethylene glycol"; those commercially available from ADEKA Corporation under the trade name "tripropylene glycol"; those commercially available from Sanyo Chemical Industries, Ltd. under the PEG series, such as "PEG-200" having a molecular weight of 200, and those commercially available from Fujifilm Wako Pure Chemical Industries, Ltd. under the diol type 400.

[0033] When a furan derivative, such as furfuryl alcohol, and a polyhydric alcohol, such as polyethylene glycol, are used, the initial setting temperature, which will be described later, can be set high in the method for producing a modified wood material, thereby increasing the yield of the components used and providing the modified wood material with properties such as suppressing cracks / breaks and / or deformation / sagging and suppressing a decrease in dimensional stability.

[0034] In a preferred embodiment, the suppression of cracking / breaking and / or deformation / sagging of the modified wood material can be 40% or less of the occurrence rate of cracking / breaking and / or deformation / sagging of the unmodified wood material, for example, 30% or less, 20% or less, 15% or less, or 10% or less. In a preferred embodiment, the anti-swelling capacity (ASE) of the modified wood material can be 50% or more, for example, 50 to 95% or 55 to 90%, which can contribute to the suppression of a decrease in dimensional stability.

[0035] The concentration of the furan derivative in the furan derivative resinification solution used in the production method of the present invention may typically be 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 %. Such a furan derivative concentration can facilitate more favorable modification of wood materials. For example, modification treatment of wood materials using the solution can easily impart to the wood materials at least one favorable property, such as suppression of cracking / breaking and / or deformation / sagging, or suppression of a decrease in dimensional stability. Furthermore, the production method of the modified wood materials can exhibit a high yield.

[0036] The concentration or amount of the polyhydric alcohol in the furan derivative resinification solution used in the production method of the present invention may typically be 0.01 to 1 mol per 1 mol of furan derivative contained in the furan derivative resinification solution, for example, 0.01 to 0.5 mol or 0.03 to 0.3 mol. Such a polyhydric alcohol, when combined with the furan derivative, can promote favorable modification of wood materials. Such a concentration or amount of the polyhydric alcohol in the furan derivative resinification solution can promote more favorable modification of wood materials. For example, modification treatment of wood materials using the solution can more easily suppress a decrease in the yield of the components used. Furthermore, modification treatment of wood materials using the solution can more easily impart to the wood materials at least one favorable property, such as suppression of cracking / cracking and / or deformation / sagging or suppression of a decrease in dimensional stability, even when polymerization is promoted at higher temperatures during the production process.

[0037] The furan derivative resinification solution used in the production method of the present invention contains an “inorganic salt that promotes polymerization of the furan derivative.” By incorporating such an inorganic salt into the furan derivative resinification solution, polymerization of the furan derivative in the solution is more suitably promoted during heating for the modification treatment.

[0038] The "inorganic salt that promotes the polymerization of the furan derivative" may be an inorganic salt that promotes the polymerization of the furan derivative by heating, particularly by heating in step 2). Here, "promoting polymerization" means that the presence of such an inorganic salt increases the rate of the polymerization reaction compared to its absence (for example, when the polymerizable monomer is present alone). Such an inorganic salt may be an inorganic salt that exhibits acidic, e.g., weak acidity, in an aqueous solution (e.g., an aqueous solution at room temperature), and may be, for example, an inorganic salt that shifts the pH of the aqueous furan derivative resin solution toward the acidic side (i.e., lowers the pH). For example, such an inorganic salt may be neutral to weakly acidic, typically pH 3 to 7 (excluding "7"), or may exhibit, for example, a pH of 4 to 6.5 or pH 5 to 6, in aqueous solution at room temperature.

[0039] 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."

[0040] In the production method of the present invention, the "inorganic salt that promotes polymerization of a furan derivative" may be an inorganic salt consisting of an anion of chloride ion and / or sulfate ion and a cation of ammonium ion and / or magnesium ion and / or hydrogen ion. Such an inorganic salt can promote more favorable modification of wood materials. For example, modification treatment of wood materials using the solution can easily impart to the wood materials at least one favorable property, such as suppression of cracking / breaking and / or deformation / sagging, and more favorable suppression of deterioration of dimensional stability, even when subjected to polymerization at higher temperatures.

[0041] In a preferred embodiment, the "inorganic salt that promotes the polymerization of a furan derivative" may be an inorganic salt having, as components, 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.

[0042] For example, the "inorganic salt that promotes the polymerization of a furan derivative" 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.

[0043] In the furan derivative resinification solution, the concentration or amount of the "inorganic salt that promotes polymerization of the furan derivative" 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., relative to 1 mol of the furan derivative in the solution. In such cases, the lower limit may be a value greater than 0 mol. For example, assuming an upper limit of 0.1 mol, the concentration or amount of the "inorganic salt that promotes the polymerization of the furan derivative" contained in the furan derivative resinification solution may be 0.001 to 0.1 mol per 1 mol of the furan derivative, 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 0.1 mol, 0.008 to 0.08 mol, or 0.009 to 0.07 mol. Such a concentration or amount of the "inorganic salt that promotes the polymerization of the furan derivative" can facilitate more suitable modification of wood materials. For example, modification treatment of wood materials using the solution can more easily suppress yield declines. Furthermore, for example, by modifying wood materials using the solution, it becomes easier to impart to the wood materials at least one desirable property, such as suppressing the occurrence of cracks / breaks and / or deformation / sagging, or suppressing a decrease in dimensional stability, even when polymerized at higher temperatures.

[0044] In certain embodiments, the furan derivative resinification solution used in the production method of the present invention may contain an "inorganic substance containing an inorganic salt that inhibits the polymerization of the furan derivative at room temperature." The incorporation of such an inorganic salt into the furan derivative resinification solution stabilizes the furan derivative 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., even when left at room temperature for a long period of time), undesired polymerization of the furan derivative (e.g., undesired 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 inhibits the polymerization of the furan derivative at room temperature" can more effectively stabilize the quality of the solution before infiltration into the wood material due to the suppression of undesired polymerization of the furan derivative, thereby more effectively suppressing variation in the properties imparted to the wood material by treatment. For example, variation in at least one property, such as the suppression of cracking / cracking and / or deformation / sagging or the suppression of a decrease in dimensional stability, can be more effectively suppressed.

[0045] The "inorganic substance containing an inorganic salt that inhibits the polymerization of a furan derivative 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 a furan derivative at room temperature" may be in the form of, for example, an ammonium salt.

[0046] The "inorganic substance containing an inorganic salt that inhibits the polymerization of furan derivatives at room temperature" may be, for example, an inorganic substance containing at least one inorganic salt selected from ammonia, ammonium carbonate, ammonium bicarbonate, etc. In short, 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 selected from the group consisting of ammonia, ammonium carbonate, and ammonium bicarbonate. This is because the inorganic substance 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 can also be an inorganic substance containing an inorganic salt that does not inhibit the polymerization of furan derivatives when heated after impregnation. Note that "inhibiting polymerization" as used herein means that the presence of such an inorganic salt-containing inorganic substance slows or stops the polymerization reaction compared to its absence (e.g., when the polymerizable monomer is present alone).

[0047] The "inorganic substance containing an inorganic salt that inhibits the polymerization of furan derivatives 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), such as an inorganic substance containing an inorganic salt that makes 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 furan derivative resin aqueous 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 during subsequent heating. In other words, the desired polymerization during the modification treatment of wood materials could be inhibited. While there are limited inorganic substances 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, for example, inorganic substances that decompose and gasify upon heating and are removed from the reaction system may be used. Typical examples include inorganic salts such as ammonium carbonate and / or ammonium hydrogen carbonate, and inorganic substances such as ammonia.

[0048] From the above perspective, the inorganic substance containing the inorganic salt in the furan 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 when heated. In other words, the "inorganic substance containing an inorganic salt that inhibits the polymerization of the furan derivative at room temperature" contained in the furan derivative resinification solution may be an inorganic substance containing an inorganic salt that decomposes (more specifically, decomposes and gasifies when heated) 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 substance containing an inorganic salt that inhibits the polymerization of the furan derivative at room temperature" contained in the furan derivative resinification solution is preferably an inorganic substance containing an inorganic salt other than sodium hydroxide and potassium hydroxide.

[0049] 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 derivative caused by heating after infiltrating the furan derivative resinification solution 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 "inorganic substances containing inorganic salts that inhibit the polymerization of the furan derivative at room temperature" in the solution makes it easier to control the degree of polymerization of the furan derivative low, and makes it easier to produce low-molecular-weight furan derivative resin in the cell wall. On the other hand, decreasing the content of "inorganic substances containing inorganic salts that inhibit the polymerization of the furan derivative at room temperature" makes it easier to control the degree of polymerization of the furan derivative high, and makes it easier to produce and accumulate high-molecular-weight furan resin in the cell lumen.

[0050] As described above, these inorganic substances containing inorganic salts as stabilizers can more effectively stabilize the state of the furan derivative resinification solution before it is impregnated into wood by inhibiting the polymerization of the furan derivative at room temperature, and therefore modification treatment using such substances can contribute to improving the properties of modified wood materials. Furthermore, it can also reduce variation in the finished state of the modified wood material, making it easier to standardize the quality of final products that use the modified wood material. 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.

[0051] 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 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.

[0052] 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 promote more favorable modification of wood materials. For example, modification treatment of wood materials using the solution can increase the yield of components used while easily imparting to the wood materials at least one property, such as suppression of cracking / breaking and / or deformation / sagging, or suppression of deterioration in dimensional stability.

[0053] The furan derivative resinification solution used in the present invention may be aqueous. That is, 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 that promotes the polymerization of the furan derivative, 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 consists essentially of water. In the present invention, the phrase "the solvent in the furan derivative resinification solution is an aqueous medium" refers to a solution in which the solvent contained in the solution consists solely of water. In other words, the furan derivative resinification solution may preferably 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.

[0054] 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).

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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, Todo fir, 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 ash, 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 board), veneer, wood chips, wood flour, and / or wood fiber (pulp) that constitute these materials, as well as non-woody lignocellulosic materials such as bamboo.

[0059] The wood materials modified by the production 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.

[0060] In a preferred embodiment, the wood material is a coniferous wood. 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 poor dimensional stability and other factors, the manufacturing method of the present invention can improve these characteristics, potentially enabling them to be used in a wider range of applications. Such coniferous wood may be, for example, cedar wood and / or cypress wood. The cedar wood and / or cypress wood may correspond to domestic coniferous wood, which will contribute favorably to the development of new uses for domestic coniferous wood and the demand for added value.

[0061] 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).

[0062] As described above, the furan derivative resinification solution used in the production method of the present invention may preferably contain two types of salts as solute components other than the furan derivative. That is, the furan derivative resinification solution used in step 1) may optionally contain a combination of two types of salts: a salt that inhibits polymerization of the furan derivative at room temperature and a salt that promotes polymerization of the furan derivative. In particular, the furan derivative resinification solution used in the production method of the present invention may be a solution containing a combination of a first inorganic salt that can act as a stabilizer and a second inorganic salt 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 increase the yield of the components used while imparting to the wood materials at least one property, such as suppressing the occurrence of cracks / breaks and / or deformation / sagging or suppressing a decrease in dimensional stability. In a preferred embodiment, the stabilizer may be an inorganic substance containing an inorganic salt that suppresses polymerization of the furan derivative at room temperature but decomposes upon heating and / or warming in step 2) (for example, warming at the "initial setting temperature" described below) (for example, an inorganic salt that decomposes and gasifies).

[0063] Preferably, a solution can be formed by combining a first inorganic salt (an inorganic substance containing an inorganic salt that inhibits polymerization of the furan derivative at room temperature) with a second inorganic salt (an inorganic salt that promotes polymerization of the furan derivative) together with the furan derivative and an aqueous solvent (a solvent containing only water as a solvent and no organic solvent). In particular, a furan derivative resinification solution containing a combination of the first inorganic salt and the second inorganic salt and a simple solvent consisting of water alone can exhibit a more pronounced effect in modifying wood materials, as described above.

[0064] In the production method of the present invention, step 1) involves permeating the wood material with a furan derivative resinification solution. 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 may be used. Step 1) may involve immersing the wood material in the furan derivative resinification solution, and / or spraying or applying the furan derivative resinification solution to the wood material, and / or impregnating the wood material with the furan derivative resinification solution under reduced pressure and / or increased pressure.

[0065] 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.

[0066] In other words, step 1) may be performed under reduced pressure below atmospheric pressure. While the reduced pressure conditions may depend on the shape and / or size of the wood material being modified, they may be, for example, reduced pressure conditions between less than atmospheric pressure and 10 hPa at temperatures below room temperature. Under such reduced pressure conditions, the penetration of the solution into the wood material can be more favorably promoted. For example, by modifying the wood material using the solution, the yield of the components used can be increased while at the same time imparting to the wood material at least one desirable characteristic, such as suppressing the occurrence of cracks / breaks and / or deformation / sagging or suppressing a decrease in dimensional stability. 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 woody material is subjected to the solution under reduced pressure conditions may typically be from 5 minutes to 16 hours, for example, from 30 minutes to 16 hours, from 1 hour to 16 hours, from 1 hour to 8 hours, from 1 hour to 4 hours, or from 1 hour to 3 hours.

[0067] 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 performed after the above-mentioned reduced pressure treatment. In such treatment, atmospheric pressure or a higher atmospheric pressure may be employed. For example, pressure conditions (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 / pressurized conditions may typically be 15 minutes to 72 hours, such as 30 minutes to 36 hours, or 1 hour to 12 hours.

[0068] In the manufacturing method of the present invention, step 2) involves carrying out a heat treatment to polymerize the furan derivative that has permeated the wood material within the wood material. The heating promotes polymerization of the furan derivative in the furan derivative resinification solution within the wood material, and the resulting resin component can modify the wood material.

[0069] The heating method in step 2) is not particularly limited as long as it can raise the temperature of the wood material permeated with the solution. For example, the heating method in step 2) 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).

[0070] Such heating may be performed at a temperature of 65 to 160°C, 65 to 150°C, 65 to 130°C, 75 to 160°C, 75 to 150°C, 75 to 130°C, or 105 to 105°C. That is, step 2) in the production method of the present invention may be performed at a temperature of 75 to 160°C. Such heating conditions can facilitate more favorable modification of the wood material. For example, modification of the wood material using the solution can increase the yield of the components used, while more easily imparting to the wood material at least one favorable property, such as suppression of cracking / breaking and / or deformation / sagging, or better dimensional stability.

[0071] The time for which the woody material is subjected to the heat treatment in step 2) may typically be 2 to 240 hours, for example, 4 to 168 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.

[0072] 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 90°C) may be carried out in an inert gas atmosphere such as water vapor and / or nitrogen gas.

[0073] In the heating step 2), the wood material permeated with the solution may be dried. For example, the heating step 2) may be performed to polymerize the furan derivative of the permeated furan derivative resinification solution in the wood material while drying the wood material. In other words, the wood material may be heated for 2 to 240 hours (for example, 3 to 192 hours, 3 to 50 hours, etc.) at a temperature of 65 to 160°C (for example, 65 to 150°C, 65 to 130°C and / or 65 to 105°C, 75 to 150°C, 75 to 130°C and / or 75 to 105°C, 80 to 150°C (for example, 80 to 130°C and / or 80 to 105°C). The polymerization of the furan derivative that has infiltrated into the wood material may be allowed to proceed by carrying out the treatment for, for example, 4 to 168 hours, 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 4 to 24 hours, 4 to 10 hours, or 4 to 8 hours), and concurrently with or subsequent to this, the wood material (which has become wet due to the infiltration of the solution) may be dried.

[0074] If desired, a stabilizer may be added to the furan derivative resinification solution to stabilize 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 in 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 facilitating more favorable modification of the wood material. In the production method of the present invention, by polymerizing the furan derivative at a higher initial setting temperature, the yield of the components used can be increased, and at least one preferable property, such as suppression of cracking / breaking and / or deformation / sagging in the modified wood material or suppression of a decrease in dimensional stability, can be easily imparted to the wood material.

[0075] The heating treatment at the "initial setting temperature" may be carried out 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 may also be considered a step-like change in temperature over time). As merely 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 some or all of the stabilizer (i.e., inorganic substances including inorganic salts that inhibit polymerization of the furan derivative at room temperature) that may be optionally contained in the furan derivative resinification solution.

[0076] 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 ~0.8T 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 = 0.3T ｉｉ ~0.5T ｉｉ etc. may also be used.

[0077] 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 90° C., such as 50 to 85° C., 50 to 80° C., 60 to 85° C., 70 to 80° C., 75 to 85° C., or 75 to 80° C. The time for which the woody 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.

[0078] 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, 60 to 100°C, 70 to 90°C, 70 to 85°C, 60 to 85°C, 60 to 80°C, or 65 to 75°C.

[0079] In a preferred embodiment, a production method using a furan derivative resinification solution containing a furan derivative that is stable in a solution such as 5-HMF as the furan derivative does not require the "wood material impregnated with the solution" to be heated 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 impregnated the wood material may be heated to the desired temperature (i.e., the heating temperature of step 2) without undergoing treatment at the "initial setting temperature." 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 heated to the "initial setting temperature." In contrast, a production method using a furan derivative resinification solution containing 5-HMF as the furan derivative can be heated to a higher initial setting temperature in the production process to increase the yield of the components used, while also making it easier to impart at least one desirable property, such as suppressing the occurrence of cracks / cracks and / or deformation / sagging or suppressing a decrease in dimensional stability. 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).

[0080] [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, a polyhydric alcohol, and an inorganic salt that promotes polymerization of the furan derivative. In certain embodiments, 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, a polyhydric alcohol, and an inorganic salt that promotes polymerization of the furan derivative.

[0081] In certain embodiments, such a solution may suitably contain two types of salts as solute components other than the furan derivative, as described above. That is, the furan derivative resinification solution of the present invention may contain a combination of two inorganic substances: "an inorganic substance containing an inorganic salt that inhibits the polymerization of the furan derivative at room temperature" and "an inorganic salt that promotes the polymerization of the furan derivative." 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, the furan derivative in the furan derivative resinification solution can be further stabilized, and at least one suitable property, such as suppression of cracking / breaking and / or deformation / sagging, or suppression of a decrease in dimensional stability, can be imparted to the wood materials.

[0082] In a preferred embodiment, the concentration of the "inorganic substance containing an inorganic salt that inhibits the polymerization of a furan derivative at room temperature" in the solution of the present invention, which can be optionally contained, may be 0.0001 to 0.004 mol per 1 mol of the furan derivative in the solution. Also, the concentration of the "inorganic salt that promotes the polymerization of a furan derivative" 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.

[0083] 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" 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." More specifically, in the 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 1 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" per 1 mol of furan derivative in the solution. When the contents of the two inorganic salts have such a relative relationship, a more suitable modification treatment solution is likely to be obtained, and when used in the modification treatment of wood materials, it becomes easier to impart to the wood materials at least one property, such as suppression of cracking / breaking and / or deformation / sagging or suppression of a decrease in dimensional stability.

[0084] The solution of the present invention is preferably characterized at least by its high stability. Therefore, even when stored for a relatively long period of time (e.g., even when a long time is required between the preparation of the solution and its use, as is expected in actual production), undesirable polymerization of the furan derivative is easily suppressed, allowing the furan derivative resinified solution to be used in a more suitable state for modification treatment. For example, the furan derivative resinified solution of the present invention does not become cloudy, insolubilized, and / or separated, even after preferably 7 days (more preferably 14 days) 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 by visual inspection).

[0085] A furan derivative resin solution with relatively high stability is particularly useful in industrial or practical processing and manufacturing. This is because it can more effectively reduce 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 undesirable phenomena such as large variations in dimensional stability that make it difficult to market the product.

[0086] Further details regarding the solution of the present invention, further specific embodiments, and other matters are explained in the above [Production method of the present invention], so explanations here will be omitted to avoid duplication.

[0087] [Modified Wood Material of the Present Invention] The modified wood material of the present invention is a modified wood material obtained by the above-mentioned production method. That is, the modified wood material of the present invention is a wood material containing at least a polymerized furan derivative that has been modified by the above-mentioned production method.

[0088] 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, a polyhydric alcohol, and an inorganic salt that promotes the polymerization of the furan derivative." Therefore, the modified wood material contains at least a furan resin formed by polymerization of the furan derivative, and in some preferred cases, may also contain the polyhydric alcohol used as a raw material, the inorganic salt (first inorganic salt and / or second inorganic salt), or a substance derived therefrom. The resin formed by polymerization is not necessarily limited to those in the category of polymers, but may also at least partially contain those in the category of oligomers.

[0089] In a preferred embodiment, the modified wood material of the present invention may exhibit the following physical properties: (Anti-swelling capacity / ASE) Anti-swelling capacity (ASE) of 50% or more, for example, 50-95%, 50-85%, or 50-65%. 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 ｃis 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.

[0090] 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.

[0091] 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).

[0092] Further specific aspects of the modified wood material of the present invention, as well as other specific matters, have been explained directly or indirectly 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.

[0093] 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.

[0094] 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, an inorganic substance including an inorganic salt that inhibits polymerization of the furan derivative at room temperature, and an inorganic salt that promotes polymerization of the furan derivative. However, the presence of components that may be unavoidably or accidentally mixed in during preparation, storage, and / or use of the solution (for example, components that are 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.

[0095] It should be noted that the present invention described above can 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 furan derivative resinification solution containing a furan derivative, a polyhydric alcohol, and an inorganic salt that promotes polymerization of the furan derivative, and 2) polymerizing the furan derivative in the impregnated furan derivative resinification solution in the wood material by heating. - Second aspect: A method for producing a modified wood material, wherein the solvent in the furan derivative resinification solution is an aqueous medium. - Third aspect: A method for producing a modified wood material, wherein the polyhydric alcohol is an alkylene glycol having 2 to 10 carbon atoms or a polyalkylene glycol obtained by polymerizing an alkylene glycol having 2 to 10 carbon atoms. - Fourth aspect: A method for producing a modified wood material, wherein the alkylene glycol is ethylene glycol or propylene glycol. - Fifth aspect: A method for producing a modified wood material, wherein the polyalkylene glycol is polyethylene glycol or polypropylene glycol. Aspect 6: The method according to Aspect 5, wherein the polyethylene glycol or polypropylene glycol has a molecular weight of 100 to 10,000. Aspect 7: The method according to any one of Aspects 1 to 6, wherein the molar ratio of the furan derivative to the polyhydric alcohol in the furan derivative resinification solution is 1:0.01 to 1:1. Aspect 8: The method according to any one of Aspects 1 to 7, wherein the inorganic salt that promotes the polymerization of the furan derivative is an inorganic salt composed 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 9: The method according to any one of Aspects 1 to 8, wherein the concentration of the inorganic salt that promotes the polymerization of the furan derivative is 0.001 to 0.1 mol per mol of the furan derivative. Aspect 10: The method according to any one of Aspects 1 to 9, wherein the furan derivative is furfuryl alcohol, and the furan derivative resinification solution further contains an inorganic substance including an inorganic salt that inhibits the polymerization of furfuryl alcohol at room temperature.- 11th aspect: The manufacturing method according to the 10th aspect, wherein the inorganic substance containing an inorganic salt that inhibits the polymerization of furfuryl alcohol at room temperature is an inorganic salt that decomposes and gasifies when heated. - 12th aspect: The manufacturing method according to the 10th or 11th aspect, wherein the inorganic substance containing an inorganic salt that inhibits the polymerization of furfuryl alcohol at room temperature is at least one selected from the group consisting of ammonium carbonate and ammonium hydrogen carbonate. - 13th aspect: The manufacturing method according to any one of the 10th to 12th aspects, wherein the concentration of the inorganic substance containing an inorganic salt that inhibits the polymerization of furfuryl alcohol at room temperature is 0.0001 to 0.004 mol per 1 mol of furfuryl alcohol. - 14th aspect: The manufacturing method according to any one of the 1st to 13th aspects, wherein step 1) is performed under reduced pressure below atmospheric pressure. - 15th aspect: The manufacturing method according to any one of the 1st to 14th aspects, wherein the heating in step 2) is performed at 60 to 200°C. Aspect 16: The manufacturing method according to any one of Aspects 1 to 15, wherein the wood material is a coniferous wood. Aspect 17: The manufacturing method according to Aspect 16, wherein the wood material is a cedar or a cypress. Aspect 18: A furan derivative resinification solution for modifying a wood material, comprising a furan derivative, a polyhydric alcohol, and an inorganic salt that promotes polymerization of the furan derivative. Aspect 19: The furan derivative resinification solution according to Aspect 18, wherein the solvent in the furan derivative resinification solution is an aqueous medium. Aspect 20: A wood material modified by the manufacturing method according to any one of Aspects 1 to 17, wherein the modified wood material comprises at least a polymerized furan derivative. Aspect 21: The modified wood material according to Aspect 20, 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.

[0096] [Study on the effect of polyhydric alcohols on heating temperature 1] In the manufacturing method of modified wood materials using furan derivatives, if the initial temperature is set higher than 60° C., the agent yield increases but the anti-swelling ability (ASE) decreases. Therefore, we combined furan derivatives and polyhydric alcohols and studied the effect on the anti-swelling ability (ASE) when the initial temperature was set higher than 60° C. A rectangular cedar sapwood (30 mm x 30 mm x 5 mm) was subjected to a furan derivative resinification solution containing 30 wt% furfuryl alcohol (Fujifilm Wako Pure Chemical Industries, Ltd.), 0.05 mol of polyethylene glycol 400 (Sanyo Chemical Industries, Ltd.), 0.01 mol of ammonium chloride, 0.0081 mol of ammonium carbonate, and water per mol of furfuryl alcohol under reduced pressure of 30 hPa or less for 1 hour. After immersion at room temperature for 24 hours, the sapwood was removed from the solution and subjected to an initial temperature of 60°C or 80°C for 48 hours. The resinified samples were then reacted at 105°C for 24 hours. Table 1 shows the calculated anti-swelling capacity (ASE) of the resinified samples prepared using the furan derivative resinification solution containing a furan derivative and a polyhydric alcohol.

[0097] The results in Table 1 show that when a furan derivative was used alone, increasing the initial setting temperature from 60°C to 80°C reduced the anti-swelling capacity (ASE). On the other hand, by combining a furan derivative with a polyhydric alcohol, it was possible to impart excellent anti-swelling capacity to wood materials when the heating temperature (initial setting temperature) was increased from 60°C to 80°C. Furthermore, the increased heating temperature reduced the rate of resinification component leaching out from the wood materials. Therefore, it was demonstrated that by incorporating a furan derivative in combination with a polyhydric alcohol into a furan derivative resinification solution, heating can be carried out at higher temperatures in the manufacturing method for modified wood materials.

[0098] [Study 2 on the influence of polyhydric alcohol on heating temperature] Resinized samples were prepared under the same conditions as in [Study 1 on the influence of polyhydric alcohol on heating temperature], except that the final heating temperature was changed from 105° C. to 130° C. or 150° C. Table 2 shows the anti-swelling ability (ASE) calculated for the resinized samples produced using a furan derivative resinified solution containing a furan derivative and a polyhydric alcohol.

[0099] The results in Table 2 demonstrate that by combining a furan derivative with a polyhydric alcohol, excellent anti-swelling properties can be imparted to wood materials, even when the final heating temperature was increased from the initial temperature of 60°C or 80°C to 130°C or 150°C. Furthermore, by further increasing the heating temperature, the rate of resinification components leaching out from the wood materials was further reduced. Therefore, by incorporating a furan derivative in combination with a polyhydric alcohol into a furan derivative resinification solution, it was demonstrated that heating can be carried out at higher temperatures in the manufacturing process for modified wood materials.

[0100] [Polyhydric Alcohol Study 1 (Ethylene Glycol, Propylene Glycol)] A 30 wt.% furfuryl alcohol resinification solution containing 0.1 or 0.2 mol of ethylene glycol or 0.05-0.2 mol of propylene glycol per 1 mol of furfuryl alcohol, 0.01 mol of ammonium chloride, 0.0081 mol of ammonium carbonate, and water was used to prepare a resinified sample. Cryptomeria japonica rectangular sapwood (30 mm x 30 mm x 5 mm) was subjected to a reduced pressure of 30 hPa or less for 1 hour. After immersion at room temperature for 24 hours, the sapwood was removed from the solution, exposed to an initial temperature of 80°C for 48 hours, and then reacted at 105°C for 24 hours. The calculated antiswelling capacity (ASE) of the resinified sample prepared using ethylene glycol is shown in Table 3.

[0101] The results in Table 3 indicate that by blending ethylene glycol or propylene glycol, which are polyhydric alcohols, with a furan derivative, evaporation of the furan derivative from the wood material is suppressed even when the wood material is subjected to a high initial temperature treatment, and excellent anti-swelling ability is imparted to the wood material with a shorter initial temperature treatment.

[0102] [Polyhydric Alcohol Study 2 (Diethylene Glycol, Dipropylene Glycol)] A furan derivative resin solution containing 30% by weight of furfuryl alcohol, 0.1 or 0.2 mol of diethylene glycol (ADEKA Corporation) or 0.05-0.2 mol of dipropylene glycol (Mitsubishi Chemical Corporation) per mol of furfuryl alcohol, 0.01 mol of ammonium chloride, 0.0081 mol of ammonium carbonate, and water was used. Cryptomeria japonica rectangular sapwood (30 mm x 30 mm x 5 mm) was subjected to a reduced pressure of 30 hPa or less for 1 hour. After immersion at room temperature for 24 hours, the sapwood was removed from the solution, exposed to an initial temperature of 80 °C for 48 hours, and then reacted at 105 °C for 24 hours to prepare a resinified sample. The calculated antiswelling capacity (ASE) of the resinified sample prepared using ethylene glycol is shown in Table 4.

[0103] The results in Table 4 indicate that by blending a furan derivative with diethylene glycol or dipropylene glycol, which are polyhydric alcohols, evaporation of the furan derivative from the wood material is suppressed even when the wood material is subjected to treatment at a high initial temperature of 80°C, and that excellent anti-swelling ability is imparted to the wood material with a shorter initial temperature treatment.

[0104] [Polyhydric Alcohol Study 3 (Polyethylene Glycol 200)] 30% by weight of furfuryl alcohol, 0.05 or 0.1 mol of polyethylene glycol 200 (manufactured by Sanyo Chemical Co., Ltd.) per 1 mol of furfuryl alcohol, 0.01 mol of ammonium chloride, 0.0081 mol of ammonium carbonate, and water were used to resinify cedar rectangular sapwood (30 mm x 30 mm x 5 mm) in a furan derivative resin solution. The sapwood was then immersed at room temperature for 24 hours, removed from the solution, and heated to an initial temperature of 60, 70, or 80 ° C. for 48 hours. The resinified samples were then reacted at 150 ° C. for 8 hours. The calculated anti-swelling capacity (ASE) of the resinified samples prepared using polyethylene glycol 200 is shown in Table 5.

[0105] The results in Table 5 show that by blending polyethylene glycol 200, a type of polyhydric alcohol, with a furan derivative, excellent anti-swelling properties can be imparted to woody materials in a shorter reaction time when the reaction temperature is heated from the initial setting of 60°C or 80°C to 150°C.

[0106] [Polyhydric Alcohol Study 4 (Polyethylene Glycol 400)] A 30% by weight furan derivative resin solution containing 0.05-0.2 mol of polyethylene glycol 400 (PEG 400) per 1 mol of furfuryl alcohol, 0.01 mol of ammonium chloride, 0.0081 mol of ammonium carbonate, and water was used to prepare resinized samples. The sapwood was then immersed in the solution for 24 hours at room temperature. The sapwood was then removed from the solution and heated to an initial temperature of 60 or 80 °C for 48 hours. The resinized samples were then heated to 150 °C for 8 hours. The calculated anti-swelling capacity (ASE) values ​​for the resinized samples prepared using PEG 400 are shown in Table 6.

[0107] The results in Table 6 show that blending polyethylene glycol 400, a type of polyhydric alcohol, with a furan derivative also imparts excellent anti-swelling properties to woody materials when the reaction is carried out by heating from the initial temperature treatment of 60°C or 80°C to 150°C.

[0108] [Study on Furan Derivatives (5-Hydroxymethylfurfural (5-HMF)] Cedar rectangular sapwood (30 mm x 30 mm x 5 mm) was immersed in a furan derivative resinization solution containing 20% ​​by weight of 5-HMF (manufactured by Combi-Blocks), 0.1 mol or 0.2 mol of dipropylene glycol, a type of polyhydric alcohol, and water per 1 mol of 5-HMF, for 24 hours at room temperature, then dried at 80°C for 3 hours and reacted at 105, 120, or 140°C for 8 hours to prepare resinified samples. The anti-swelling ability (ASE) calculated for the 5-HMF resinified samples prepared using various accelerators is shown in Table 7.

[0109] The results in Table 7 show that when 5-HMF, a type of furan derivative, is used in combination with a polyhydric alcohol, excellent anti-swelling ability is imparted to wood materials with a shorter reaction treatment time.

[0110] 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 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 furan derivative resinification solution containing a furan derivative, a polyhydric alcohol, and an inorganic salt that promotes polymerization of the furan derivative; 2) A step of polymerizing the furan derivative of the permeated furan derivative resinification solution in the wood material by heating. The manufacturing method comprising:

2. The method according to claim 1 , wherein the solvent in the furan derivative resinification solution is an aqueous medium.

3. 3. The method according to claim 1, wherein the polyhydric alcohol is an alkylene glycol having 2 to 10 carbon atoms or a polyalkylene glycol obtained by polymerizing an alkylene glycol having 2 to 10 carbon atoms.

4. The process according to claim 3, wherein the alkylene glycol is ethylene glycol or propylene glycol.

5. The process according to claim 3, wherein the polyalkylene glycol is polyethylene glycol or polypropylene glycol.

6. The method according to claim 5, wherein the polyethylene glycol or polypropylene glycol has a molecular weight of 100 to 10,000.

7. 3. The method according to claim 1, wherein the molar ratio of the furan derivative to the polyhydric alcohol in the furan derivative resinification solution is 1:0.01 to 1:

1.

8. 3. The process according to claim 1, wherein the inorganic salt that promotes the polymerization of the furan derivative 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.

9. 3. The method according to claim 1, wherein the concentration of the inorganic salt that promotes the polymerization of the furan derivative is 0.001 to 0.1 mol per 1 mol of the furan derivative.

10. 3. The method according to claim 1, wherein the furan derivative is furfuryl alcohol, and the furan derivative resinification solution further contains an inorganic substance including an inorganic salt that inhibits polymerization of furfuryl alcohol at room temperature.

11. The method according to claim 10, wherein the inorganic substance containing an inorganic salt that inhibits polymerization of furfuryl alcohol at room temperature is an inorganic salt that is decomposed and gasified by heating.

12. The method according to claim 10, wherein the inorganic substance containing an inorganic salt that inhibits polymerization of furfuryl alcohol at room temperature is at least one selected from the group consisting of ammonium carbonate and ammonium hydrogen carbonate.

13. The method according to claim 10, wherein the concentration of the inorganic substance containing an inorganic salt that inhibits polymerization of furfuryl alcohol at room temperature is 0.0001 to 0.004 mol per 1 mol of furfuryl alcohol.

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

15. The method according to claim 1 or 2, wherein the heating in step 2) is carried out at 60 to 200° C.

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

17. The manufacturing method according to claim 16, wherein the wood material is cedar wood or cypress wood.

18. A furan derivative resinification solution for modifying wood materials, comprising: A furan derivative resinification solution comprising a furan derivative, a polyhydric alcohol, and an inorganic salt that promotes polymerization of the furan derivative.

19. The furan derivative resinification solution according to claim 18, wherein the solvent in the furan derivative resinification solution is an aqueous medium.

20. 3. A wood material modified by the method according to claim 1 or 2, which comprises at least a polymerized furan derivative.

21. The modified wood material according to claim 20, 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.