Modified wood, method for manufacturing modified wood, and musical instrument

Abstract

Provided are a modified wood impregnated with a modified component that can be easily manufactured without purification and has low internal loss, a method for manufacturing the modified wood, and a musical instrument using the wood. A modified wood having wood and a logwood extract component impregnated in the wood is used. The logwood extract component is impregnated to a depth of 1 mm or more on average from the surface of the wood, the modulus of elasticity in the fiber direction of the wood after impregnation with the logwood extract component is 7 GPa or more and 20 GPa or less, and the modulus of elasticity in the radial direction is 0.5 GPa or more and 2.5 GPa or less.

Description

[0001] This application is a divisional application of the invention patent application filed on April 20, 2020, with application number 202010310593.7, entitled "Modified Wood, Method for Manufacturing Modified Wood and Musical Instrument". Technical Field

[0002] This invention relates to modified wood, a method for manufacturing modified wood, and musical instruments. Background Technology

[0003] Wood is used in musical instruments such as stringed instruments, percussion instruments, and wind instruments. For musical instruments, wood with low internal loss (tanδ) is preferred to obtain good tone quality. However, wood with suitable low internal loss is relatively rare. Therefore, there is a need to modify the wood to reduce internal loss.

[0004] Previously, methods to reduce internal damage in wood included using resorcinol and formaldehyde to modify the wood. However, this method has the drawback of producing wood with a formaldehyde odor due to the use of formaldehyde.

[0005] As a method to reduce internal loss of wood without using formaldehyde, there are methods for modifying wood using hematoxylin. For example, Patent Document 1 describes a method for modifying wood in which a solution containing hematoxylin and / or its derivatives is impregnated or coated onto the wood, and then dried to a target moisture content.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent No. 3520962 Summary of the Invention

[0009] The problem that the invention will solve

[0010] However, in wood modification methods using solutions containing hematoxylin and / or its derivatives, there is a drawback: the high price of hematoxylin and / or its derivatives. Hematoxylin and / or its derivatives are manufactured by extraction and purification from legumes. The purification process to obtain hematoxylin and / or its derivatives is laborious, contributing to their higher price.

[0011] The present invention was made in view of the above circumstances, and the objective is to provide modified wood impregnated with modified components that can be easily manufactured without purification and with low internal loss, and musical instruments using the modified wood.

[0012] Furthermore, the objective of this invention is to provide a method for modifying wood by using a modifying component that can be easily manufactured without purification, thereby reducing internal losses in the wood.

[0013] Methods for solving problems

[0014] In order to solve the above-mentioned problems, the inventors have conducted in-depth research on a modifier that can be easily manufactured without purification, which is a modifier that is impregnated in wood to reduce internal loss of wood.

[0015] As a result, the inventors discovered that sappanwood extract could be used as a modifying component, and thus conceived of this invention. That is, this invention relates to the following matters.

[0016] [1] A modified wood has wood and a sappanwood extract impregnated in the wood, wherein the sappanwood extract is impregnated to a depth of at least 1 mm on average from the surface of the wood, and the elastic modulus of the wood in the fiber direction after impregnation with the sappanwood extract is 7 GPa or more and 20 GPa or less, and the elastic modulus in the radial direction is 0.5 GPa or more and 2.5 GPa or less.

[0017] [2] According to the modified wood described in [1], the sappanwood extract is not a substance that is powdered by freeze-drying.

[0018] [3] According to the modified wood described in [1], the internal loss in the fiber direction of the wood is 4 × 10⁻⁶. -3 Above 12×10 -3 The internal loss of the wood in the radial direction is 12 × 10⁻⁶. -3 Above 25×10 -3 the following.

[0019] [4] According to the modified wood described in [1], the mass of the sappanwood extract is 8% to 12% of the mass of the sappanwood before water extraction.

[0020] [5] According to the modified wood described in [4], the mass of the water used in the extraction is 10 to 20 times the mass of the sappanwood.

[0021] [6] A manufacturing method for modified wood, characterized in that it includes an impregnation step of impregnating wood with a sappanwood extract, wherein the sappanwood extract is impregnated to a depth of at least 1 mm on average from the surface of the wood, and the elastic modulus of the wood after impregnation with the sappanwood extract is at least 7 GPa and less than 20 GPa in the fiber direction, and at least 0.5 GPa to 2.5 GPa in the radial direction, more preferably 0.8 to 2 GPa.

[0022] [7] According to the method for manufacturing modified wood described in [6], before the impregnation process, there is an extraction process for extracting the sappanwood extract from sappanwood using water, in which the sappanwood extract is not pulverized by freeze-drying.

[0023] [8] According to the method for manufacturing modified wood described in [6], the internal loss of the wood in the fiber direction is 4 × 10⁻⁶. -3 Above 12×10 -3 The internal loss of the wood in the radial direction is 12 × 10⁻⁶. -3 Above 25×10 -3 the following.

[0024] [9] According to the method for manufacturing modified wood as described in [7], the mass of the sappanwood extract is 8% to 12% of the mass of the sappanwood before water extraction.

[0025]

[10] According to the method for manufacturing modified wood described in [7], the mass of the water used in the extraction process is 10 to 20 times the mass of the sappanwood.

[0026]

[11] A musical instrument comprising modified wood as described in any one of [1] to [5], or modified wood obtained by any one of [6] to

[10] .

[0027] Invention Effects

[0028] The modified wood of the present invention contains wood and a sappanwood extract impregnated in the wood.

[0029] Sappanwood extract is obtained simply by extracting sappanwood with water, and can be easily manufactured without purification.

[0030] Furthermore, the sappanwood extract is a modifying component that reduces the internal loss of wood through impregnation. Therefore, the modified wood of the present invention has low internal loss.

[0031] The method for manufacturing modified wood according to the present invention includes an impregnation step of impregnating wood with a component extracted from sappanwood.

[0032] According to the method for manufacturing modified wood of the present invention, the internal loss of wood can be reduced by using a modifying component that can be easily manufactured without purification.

[0033] The musical instrument of this invention uses the modified wood of this invention. Because the modified wood of this invention has low internal loss, the musical instrument of this invention has good sound quality. Attached Figure Description

[0034] Figure 1This is a top view of an acoustic guitar, which is an example of the musical instrument of the present invention.

[0035] Explanation of reference numerals in the attached figures

[0036] 1. Acoustic guitar (musical instrument), 2. Body, 3. Fingers. Detailed Implementation

[0037] The following describes in detail the embodiments in which the present invention is applied.

[0038] [Modified Timber]

[0039] The modified wood of this embodiment has wood and a sappanwood extract impregnated in the wood.

[0040] In this embodiment, the impregnation of sappanwood extract in the wood means that the sappanwood extract has penetrated to a depth of at least 0.5 mm from the surface of the wood, preferably at least 2 mm.

[0041] The preferred wood material for use as modified timber has an internal loss of 12 × 10⁻⁶ in the radial direction (R direction). -3 Of the above, 15×10 is more preferred. -3 The above. The internal loss in the radial direction is 12 × 10. -3 The above-mentioned woods are preferred as materials for improving wood because the internal loss caused by impregnation with sappanwood extract is significantly reduced.

[0042] Furthermore, the internal radial loss of the wood used as the modified wood material is preferably 25 × 10⁻⁶. -3 The following is a more preferred option: 23×10 -3 The internal loss in the radial direction is 25 × 10⁻⁶. -3 The following woods, when impregnated with sappanwood extract, are readily suitable as musical instrument materials, with an internal radial loss of 22 × 10⁻⁶. -3 The following modified woods are preferred.

[0043] The preferred wood material for use as modified wood is wood with an internal loss of 4 × 10⁻⁶ in the fiber direction (L direction). -3 Of the above, 5×10 is more preferred. -3 The above. The internal loss in the fiber direction is 4 × 10. -3 The above-mentioned woods are preferred as materials for improving wood because they significantly reduce the internal loss caused by the impregnation of sappanwood extract.

[0044] Furthermore, the preferred wood material for use as modified wood has an internal fiber loss of 12 × 10⁻⁶. -3 The following is a preferred option: 10×10-3 The internal loss in the fiber direction is 12 × 10⁻⁶. -3 The following woods, when impregnated with sappanwood extract, are readily suitable as musical instrument materials, with an internal fiber loss of 9 × 10⁻⁶. -3 The following modified woods are preferred.

[0045] In this embodiment, "internal loss (tanδ)" refers to the value obtained by the method shown below.

[0046] Using the two-end free flexure vibration method (Yano et al.: Journal of the China Wood Science, 32, 984-989 (1986)), the specific dynamic Young's modulus was obtained from the resonant frequency using the Euller-Bernoulli formula. In addition, the logarithmic decay rate was obtained from the free decay curve, and it was converted to tanδ by dividing it by π, which was set as the value of the internal loss of the vibration decay rate.

[0047] Unless otherwise specified, the “internal loss (tanδ)” of wood or modified wood in this embodiment refers to the measured value of wood or modified wood that has been heated to a stable and absolutely dry state in an oven at 105°C and then placed in an environment at 22°C and 60% relative humidity until its quality is stable.

[0048] The type of wood used as the modified wood is not particularly limited, but it is preferably selected from maple, spruce, mahogany, beech, birch, or walnut. These woods are readily available, ensuring a stable supply of modified wood obtained by impregnating them with sappanwood extract. Furthermore, due to their low internal loss, they are suitable as materials for high-performance musical instruments.

[0049] Among the wood species used as modified wood, the preferred choice is any one of maple, spruce, beech, birch, or walnut. These woods show significant reduction in internal loss through impregnation with sappanwood extract. Therefore, high-performance modified wood with reduced internal loss, suitable for use as a musical instrument material, is preferred through impregnation with sappanwood extract.

[0050] The preferred mass of the sappanwood extract in the modified wood of this embodiment is 0.5% to 10% of the absolute dry mass of the wood (wood before impregnation with the sappanwood extract), more preferably 1% to 7%. If the mass ratio of the sappanwood extract in the modified wood to the absolute dry mass of the wood is 0.5% or more, it becomes modified wood that significantly reduces internal losses caused by impregnation with the sappanwood extract. However, even if the mass ratio of the sappanwood extract in the modified wood to the absolute dry mass of the wood exceeds 10%, the effect of reducing internal losses caused by impregnation with the sappanwood extract is saturated. Therefore, the preferred mass of the sappanwood extract in the modified wood is 10% or less of the absolute dry mass of the wood.

[0051] In this embodiment, the "ratio of the mass of the sappanwood extract in the modified wood to the mass of the wood" is a value calculated by measuring the mass of the wood in an absolutely dry state (before treatment) and the mass of the modified wood in an absolutely dry state (after treatment), respectively, and using the formula shown below.

[0052] [{(Post-treatment - Pre-treatment) / Pre-treatment} × 100 (%)]

[0053] The preferred relative density of the dry wood of the modified wood in this embodiment is 0.2–1.2 g / cm³. -3 More preferably, it is 0.3–1.0 g / cm³. -3 If the relative density of the dry wood of the modified timber is 0.2 g / cm³ -3 The above demonstrates that the instrument possesses sufficient rigidity for its function as a musical instrument. Furthermore, if the relative density of the dry wood of the modified wood is 1.2 g / cm³... -3 The instrument used in this example vibrates fully during performance, resulting in good volume and sound quality.

[0054] The modulus of elasticity in the fiber direction (L direction) of the modified wood in this embodiment is preferably 7 to 20 GPa, more preferably 8 to 18 GPa. The modulus of elasticity in the radial direction (R direction) of the modified wood is preferably 0.5 to 2.5 GPa, more preferably 0.8 to 2 GPa. If the moduli of elasticity in both the fiber direction and the radial direction of the modified wood are within the above ranges, it is more suitable as a material for musical instruments. If the modulus of elasticity in the fiber direction is 7 GPa or more and the modulus of elasticity in the radial direction is 0.5 GPa or more, then the musical instrument using it has sufficient rigidity as a musical instrument. In addition, if the modulus of elasticity in the radial direction is 2.5 GPa or less, it is easy to ensure that the difference between the modulus of elasticity in the radial direction and the modulus of elasticity in the fiber direction is small, making it a modified wood that is easy to obtain for musical instruments with the desired tone.

[0055] [Methods for manufacturing modified wood]

[0056] The method for manufacturing the modified wood according to this embodiment will be described.

[0057] The method for manufacturing modified wood according to this embodiment includes an impregnation step of impregnating wood with a sappanwood extract. Preferably, the method for manufacturing modified wood according to this embodiment includes an extraction step of extracting the sappanwood extract from sappanwood using water before the impregnation step.

[0058] (Extraction process)

[0059] In the extraction process, water is used to extract sappanwood extracts from sappanwood.

[0060] The extractor used in the extraction process is not particularly limited.

[0061] The shape of the sappanwood used in the extraction process is not particularly limited, but for efficient extraction, it is preferred to use sappanwood in flake or powder form, and it is particularly preferred to use sappanwood in powder form.

[0062] The extraction process is not specifically limited, but there are methods such as the following.

[0063] In the extraction process, it is preferable to carry out a first step of using sappanwood as the material to be extracted and a second step of using sappanwood separated from the sappanwood extract as the material to be extracted.

[0064] The first step involves placing sappanwood in water and heating it at a specified temperature for a specified time to obtain a sappanwood extract. The next step is to remove the sappanwood from the extract to obtain a sappanwood solution.

[0065] The quality of the water used for extraction in the first step is not particularly limited, but in order to efficiently extract the extract from sappanwood, it is preferred to use 10 to 20 times the mass of sappanwood.

[0066] The extraction temperature in the first step is not particularly limited, but in order to efficiently extract the components from sappanwood, 95-98℃ is preferred.

[0067] The extraction time in the first step is, for example, 1 to 2 hours.

[0068] In the first step, the method for removing sappanwood from the sappanwood extract can be appropriately determined according to the shape of the sappanwood used and is not particularly limited. For example, methods such as using a metal mesh or cloth to remove the sappanwood extract can be used.

[0069] The second step involves placing the sappanwood separated from the sappanwood extract into water, heating it at a specified temperature for a specified time to obtain the sappanwood extract, and then removing the sappanwood from the sappanwood extract to obtain a sappanwood solution.

[0070] The quality of the water used for extraction in the second step is not particularly limited, but in order to efficiently extract the sappanwood extract, it is preferably set to 10 to 20 times the mass of sappanwood separated from the sappanwood extract.

[0071] In order to efficiently extract the components from sappanwood, the extraction temperature and time in the second step are preferably set within the same range as in the first step.

[0072] In the second step, the method for removing sappanwood from the sappanwood extract can be the same as that in the first step.

[0073] The second step can be performed multiple times as needed.

[0074] The number of extractions can also be determined based on the shape of the sappanwood, the extraction temperature and extraction time in the first and second processes.

[0075] All the sappanwood solutions obtained through the first and second processes are collected and used in the impregnation process described later.

[0076] In this embodiment, during the extraction process, it is preferable to continue extraction until the mass of the solid component extracted from sappanwood is 8-12% of the mass of sappanwood before extraction, and more preferably until it is 9-11%. By continuing extraction until the mass of the solid component extracted from sappanwood is 8% or more of the mass of sappanwood before extraction, the extractable components contained in sappanwood can be sufficiently extracted, and the compositional deviation of the extracted components is small, resulting in a sappanwood solution with stable quality. Furthermore, when using water to extract sappanwood components, it is difficult to continue extraction until the mass of the solid component extracted from sappanwood exceeds 12% of the mass of sappanwood before extraction. Therefore, it is preferable that the mass of the solid component extracted from sappanwood is 12% or less of the mass of sappanwood before extraction.

[0077] The mass ratio of the solid component extracted from sappanwood to the mass of sappanwood before extraction varies depending on the shape of the sappanwood, the amount of water used in the extraction, the extraction temperature, the extraction time, and the number of extractions. Specifically, by reducing the size of the sappanwood, increasing the amount of water used in the extraction, increasing the extraction temperature, lengthening the extraction time, and increasing the number of extractions, the mass ratio of the solid component extracted from sappanwood to the mass of sappanwood before extraction can be increased.

[0078] Therefore, by varying the shape of the sappanwood, the amount of water used for extraction, the extraction temperature, the extraction time, and the number of extractions to extract sappanwood components, the ratio of the mass of the solid component extracted from the sappanwood to the mass of the sappanwood before extraction under each condition can be determined in advance. Thus, the conditions under which the mass of the solid component extracted from the sappanwood becomes a specified amount can be determined.

[0079] In this embodiment, the mass of the solid component extracted from sappanwood is a value obtained by calculating the mass of the solid component contained in all sappanwood solutions after collecting a portion of the sappanwood solution obtained from the extraction process, taking a portion as a sample, evaporating and drying it.

[0080] The sappanwood solution obtained through the extraction process (a collection of all sappanwood solutions obtained through the first and second processes) can also be concentrated or diluted as needed to adjust the concentration of the sappanwood extract components in the sappanwood solution.

[0081] Methods for concentrating sappanwood solution include, for example, heating the sappanwood solution to evaporate the water contained in it. In this case, the sappanwood solution can also be heated under reduced pressure to reduce the time required for concentration.

[0082] Methods for diluting sappanwood solution include, for example, adding water to the sappanwood solution.

[0083] (Immersion process)

[0084] In the impregnation process, the sappanwood extract is impregnated into the wood. The preferred impregnation process is one in which the wood is impregnated in a sappanwood solution.

[0085] The preferred impregnation process is to impregnate the wood in a sappanwood solution containing 0.1 to 5.0% by mass of sappanwood extract, and more preferably, to impregnate the wood in a sappanwood solution containing 0.5 to 4.0% by mass of sappanwood extract. If the sappanwood extract in the sappanwood solution is 0.1% by mass or more, it is easier to obtain modified wood with a sappanwood extract content of 0.5% or more of the wood's mass, which is more preferred. Furthermore, if the sappanwood extract in the sappanwood solution is 5.0% by mass or less, it is easier to obtain modified wood with a sappanwood extract content of 10% or less of the wood's mass, which is also more preferred.

[0086] The quality of the sappanwood extract in the modified wood can be controlled according to the type of wood used as the material and the thickness of the board, the concentration of the sappanwood extract in the sappanwood solution used to impregnate the wood, and as needed, for example, by performing one or more of the methods selected from (1) to (5) shown below to promote the impregnation of the sappanwood extract into the wood once or more.

[0087] (1) Method for transmitting ultrasonic waves through a sappanwood solution used to impregnate wood.

[0088] (2) Method of making holes in the wood and then impregnating it with sappanwood solution

[0089] (3) A method for reducing the pressure on wood by immersing it in a sappanwood solution.

[0090] (4) A method of pressurizing wood in a state of being impregnated with sappanwood solution.

[0091] (5) Method of heating the sappanwood solution to impregnate the wood

[0092] The method described in (3) above for depressurizing wood in a state of sappanwood solution immersion can be exemplified by placing the wood in the sappanwood solution immersion state in a sealed container at a pressure of 20-50 hPa for 30 minutes to 1 hour. By depressurizing the wood in the sappanwood solution immersion state, air is expelled from the wood, promoting the immersion of sappanwood extracts into the wood. After performing the method described in (3) above, the wood restored to normal pressure can continue to be immersed in sappanwood solution.

[0093] The method of pressurizing wood in the state of being impregnated with sappanwood solution as described in (4) above can be exemplified by pressurizing wood impregnated with sappanwood solution in a sealed container at a pressure of 2 to 10 MPa for 30 minutes to 2 hours. The method of pressurizing wood in the state of being impregnated with sappanwood solution as described in (4) above can also be performed on wood after performing the method described in (3) above.

[0094] The above-mentioned method of heating the sappanwood solution to impregnate the wood can be exemplified by heating the sappanwood solution to 50°C to 90°C.

[0095] When the wood used as material is a wood veneer with a board thickness of less than 1 mm, the concentration of the sappanwood extract in the sappanwood solution used to impregnate the wood can be controlled to ensure that the sappanwood extract is fully impregnated in the wood.

[0096] When the wood used as material is a wood veneer with a board thickness of 1 mm to several mm, it is preferable to use the method described above (3) to depressurize the wood by immersing it in a sappanwood solution.

[0097] When the wood used as material is a high-density material with a board thickness of more than a few mm, it is preferable to pressurize the wood by using the method described in (4) above after performing the method described in (3) above, so that the wood is impregnated in the sappanwood solution.

[0098] In the impregnation process, it is preferable to perform the wood drying process after the process of impregnating the wood with the sappanwood solution.

[0099] The process of drying wood can be, for example, a natural drying process in which the wood is placed in a normal temperature and pressure environment for about one week to several months, an artificial drying process in which the temperature and humidity are controlled to achieve the desired moisture content, or an artificial drying process after a natural drying process.

[0100] The modified wood of this embodiment contains wood and a sappanwood extract impregnated in the wood. The sappanwood extract is obtained simply by extracting sappanwood with water and can be easily manufactured without purification.

[0101] Furthermore, the sappanwood extract is a modifying component that reduces the internal loss of wood through impregnation. Therefore, the modified wood of this embodiment has lower internal loss.

[0102] Furthermore, the method for manufacturing modified wood in this embodiment includes an impregnation step of impregnating the wood with a sappanwood extract. Therefore, according to the method for manufacturing modified wood in this embodiment, the internal loss of the wood can be reduced by using a modifying component that can be easily manufactured without purification. Additionally, the method for manufacturing modified wood in this embodiment is preferred because it reduces the internal loss of the wood without using chemicals such as formaldehyde.

[0103] In the method for manufacturing modified wood according to this embodiment, the rate of change in the relative density of the dry wood in the wood used as material and the modified wood obtained after the impregnation process [{(after treatment - before treatment) / before treatment} × 100 (%)] is relatively small. The rate of change in the relative density of the dry wood varies depending on the type of wood used as material and the mass ratio of the sappanwood extract. The rate of change in the relative density of the dry wood is preferably in the range of -5% to 5%, and more preferably in the range of -4% to 4%. If the rate of change in the relative density of the dry wood is -5% to 5%, then by performing an impregnation process on wood with a relative density of dry wood suitable for use as a musical instrument, modified wood with low internal loss can be obtained without hindering the relative density of the dry wood.

[0104] In the method for manufacturing modified wood according to this embodiment, the rate of change of the elastic modulus in the fiber direction (L direction) and the radial direction (R direction) of the wood used as material and the modified wood obtained after the impregnation process [{(after treatment - before treatment) / before treatment} × 100 (%)] is relatively small. The rate of change of the elastic modulus in the fiber direction and the radial direction varies depending on the type of wood used as material and the mass ratio of the sappanwood extract. The rate of change of the elastic modulus in the fiber direction is preferably -7 to 2%. The rate of change of the elastic modulus in the radial direction is preferably -6 to 20%. If the rate of change of the elastic modulus in the fiber direction and the radial direction is within the above range, modified wood with an elastic modulus suitable for use as a musical instrument and low internal loss can be obtained by impregnating wood with an elastic modulus suitable for use as a musical instrument.

[0105] [Musical Instruments]

[0106] Next, the musical instrument of the present invention will be described in detail by way of example.

[0107] Figure 1 This is a top view showing an acoustic guitar, an example of a musical instrument according to the present invention. Figure 1 In the diagram, reference numeral 1 indicates an acoustic guitar, reference numeral 2 indicates the body, and reference numeral 3 indicates the fretboard.

[0108] The acoustic guitar 1 of this embodiment uses the modified wood described above as the material for the body 2 and / or the fingerboard 3. The modified wood of this embodiment, used as the material for the body 2 and / or the fingerboard 3, has low internal loss. Therefore, the acoustic guitar 1 of this embodiment has good sound quality.

[0109] "Other examples"

[0110] The musical instrument of the present invention is not limited to the embodiments described above.

[0111] In this embodiment, an acoustic guitar is used as an example of the musical instrument of the present invention. However, the musical instrument of the present invention can use the modified wood of the present invention and is not limited to an acoustic guitar. In addition to the acoustic guitar, stringed instruments such as violins, percussion instruments such as drums, keyboard instruments such as pianos, and wind instruments can be listed as musical instruments of the present invention.

[0112]

Example

[0113] The present invention will be further described in detail below through examples and comparative examples. However, the present invention is not limited to the following examples.

[0114] Example 1

[0115] The extract of sappanwood was obtained from powdered sappanwood using hot water (extraction process). The mass of the solid component extracted from sappanwood through the extraction process was 10% of the mass of sappanwood.

[0116] Next, water is added to the sappanwood solution obtained through the extraction process to obtain a sappanwood solution containing 0.7% by mass of sappanwood extract.

[0117] (wood)

[0118] As timber, two sheets of maple (samples No. 1 and 2) with a length of 180 mm in the L direction (fiber direction), a length of 20 mm in the R direction (radius direction), and a thickness of 4.5 mm were prepared (hereinafter referred to as maple (L)).

[0119] Next, each piece of maple (L) was heated in an oven at 105°C until it reached a stable, absolutely dry state, and its mass was measured (before treatment, as shown in Table 1). Each piece of maple (L) in the absolutely dry state was then subjected to a humidification treatment at 22°C and 60% relative humidity until its mass stabilized. The relative density and modulus of elasticity of the dry wood were measured using the methods described below, and the internal loss (tanδ) was also measured using the same methods (before treatment, as shown in Table 1). The results are presented in Table 1.

[0120] (Method for determining the relative density of dry wood)

[0121] The dimensions of each maple log (L) were measured using calipers, and the volume of each maple log (L) was calculated. The relative density of the dry wood was calculated by dividing the volume of each maple log (L) by its mass.

[0122] (Methods for determining the modulus of elasticity)

[0123] Using the two-end free flexure vibration method (Yano et al.: Journal of the Wood Science Society, 32, 984-989 (1986)), the specific dynamic Young's modulus was obtained through the Euller-Bernoulli formula of the resonant frequency and set as the elastic modulus.

[0124] (Immersion process)

[0125] Next, each maple (L) piece with internal loss measured was placed in a sealed container while immersed in a sappanwood solution containing 0.7% by mass of sappanwood extract, and the pressure was reduced to 30 hPa for a certain period of time. Afterward, each maple (L) piece was restored to a normal temperature and pressure environment and then immersed in the sappanwood solution for a certain period of time.

[0126] Subsequently, each maple (L) was removed from the sappanwood solution and allowed to dry naturally under normal temperature and pressure to obtain two sheets of modified wood from Example 1.

[0127] The modified wood obtained in Example 1 was examined under a microscope. The results confirmed that the sappanwood extract penetrated to an average depth of more than 1 mm from the wood surface.

[0128] Calculation of the mass ratio of sappanwood extract components

[0129] Each modified wood obtained in this way was heated in an oven at 105°C until it was in a stable and absolutely dry state. The mass of each wood was measured (after treatment in Table 1). The rate of change between the modified wood and the untreated wood was calculated [{(after treatment - before treatment) / before treatment} × 100 (%)] and its average value was set as the ratio of the mass of the sappanwood extract in the modified wood to the mass of the wood.

[0130] Furthermore, each modified wood, which was to be in an absolutely dry state, was subjected to humidification treatment at a temperature of 22°C and a relative humidity of 60% until its quality stabilized. Using the above method, the relative density, modulus of elasticity, and internal loss of the dry wood were measured, and the rate of change before treatment [{(after treatment - before treatment) / before treatment} × 100 (%)] and its average value (after treatment in Table 1) were calculated. The results are shown in Table 1.

[0131] Table 1

[0132]

[0133] Example 2

[0134] As for the wood, except that two sheets (samples No. 1 and 2) of maple wood (hereinafter referred to as maple (R)) with a length of 20 mm in the L direction (fiber direction), a length of 180 mm in the R direction (radial direction), and a thickness of 4.5 mm were used, the modified wood of Example 2 was obtained in the same manner as in Example 1.

[0135] Example 3

[0136] The sappanwood solution obtained by performing the extraction process in the same manner as in Example 1 was heated to evaporate the water contained in the sappanwood solution, thereby obtaining a sappanwood solution containing 1.8% by mass of sappanwood extract. Except for using the sappanwood solution containing 1.8% by mass of the obtained sappanwood extract, the modified wood of Example 3 was obtained in the same manner as in Example 1.

[0137] Example 4

[0138] As for the wood, except that maple (R) was used, the modified wood of Example 4 was obtained in the same manner as in Example 3.

[0139] Example 5

[0140] The sappanwood solution obtained by performing the extraction process in the same manner as in Example 1 was heated to evaporate the water contained in the sappanwood solution, thereby obtaining a sappanwood solution containing 5.1% by mass of sappanwood extract. Except for using the sappanwood solution containing 5.1% by mass of the obtained sappanwood extract, the modified wood of Example 5 was obtained in the same manner as in Example 1.

[0141] Example 6

[0142] As for the wood, except that maple (R) was used, the modified wood of Example 6 was obtained in the same manner as in Example 6.

[0143] Regarding the maple (R) used in Examples 2 to 6, the mass, relative density of dry wood, modulus of elasticity, and internal loss (before treatment in Table 1) were measured in the same manner as in Example 1.

[0144] Furthermore, the cross-sections of the modified wood from Examples 2 to 6 were observed in the same manner as in Example 1. As a result, for each type of modified wood, it was confirmed that the sappanwood extract penetrated to an average depth of 1 mm or more from the surface of the wood.

[0145] In addition, similar to Example 1, the mass of each modified wood from Examples 2 to 6, set to an absolutely dry state (after treatment in Table 1), was measured, the rate of change before treatment and its average value were determined, and the mass ratio of the sappanwood extract components was calculated.

[0146] Furthermore, the modified wood samples from Examples 2 to 6, which were set to an absolutely dry state, were conditioned at 22°C and 60% relative humidity until their quality stabilized. The relative density, modulus of elasticity, and internal loss of the dry wood were measured in the same manner as in Example 1, and the rate of change before treatment and their average values ​​were calculated (after treatment in Table 1). The results are shown in Table 1.

[0147] As shown in Table 1, it was confirmed that by immersing maple (L) and maple (R) in sappanwood extract, the internal loss of maple (L) and maple (R) was reduced.

[0148] Furthermore, it is known that when maple (R) is used as timber, the absolute value of the rate of change of internal loss is greater than that when maple (L) is used, resulting in a greater reduction effect of internal loss caused by the impregnation of sappanwood extract.

[0149] Furthermore, based on the results of Examples 1 to 6, it can be seen that the more sappanwood extract containing a large amount of sappanwood extract components is used, the greater the reduction in internal loss.

[0150] Example 7

[0151] The modified wood samples from Example 1 were conditioned at 35°C and 95% relative humidity until their quality stabilized. The relative density, modulus of elasticity, and internal loss of the dry wood were measured using the methods described above, and their average values ​​were calculated (after treatment, as shown in Table 2). The results are presented in Table 2.

[0152] Example 8

[0153] The modified wood samples from Example 2 were conditioned at 35°C and 95% relative humidity until their quality stabilized. The relative density, modulus of elasticity, and internal loss of the dry wood were measured using the methods described above, and their average values ​​(after treatment, as shown in Table 2) were calculated. The results are presented in Table 2.

[0154] Example 9

[0155] The modified wood samples from Example 3 were conditioned at 35°C and 95% relative humidity until their quality stabilized. The relative density, modulus of elasticity, and internal loss of the dry wood were measured using the methods described above, and their average values ​​were calculated (after treatment, as shown in Table 2). The results are presented in Table 2.

[0156] Example 10

[0157] The modified wood samples from Example 4 were conditioned at 35°C and 95% relative humidity until their quality stabilized. The relative density, modulus of elasticity, and internal loss of the dry wood were measured using the methods described above, and their average values ​​(after treatment, as shown in Table 2) were calculated. The results are presented in Table 2.

[0158] Example 11

[0159] The modified wood samples from Example 5 were conditioned at 35°C and 95% relative humidity until their quality stabilized. The relative density, modulus of elasticity, and internal loss of the dry wood were measured using the methods described above, and their average values ​​(after treatment, as shown in Table 2) were calculated. The results are presented in Table 2.

[0160] Table 2

[0161]

[0162] Comparative Example 1

[0163] Two sheets of maple (L) (samples No. 1 and 2) were prepared and conditioned at 35°C and 95% relative humidity until the quality stabilized. The relative density, modulus of elasticity, and internal loss of the dry wood were measured in the same manner as in Example 1, and the average values ​​were calculated (before treatment in Table 2). The results are shown in Table 2.

[0164] Comparative Example 2

[0165] Two pieces of maple (R) (samples No. 1 and 2) were prepared and conditioned at 35°C and 95% relative humidity until their quality stabilized, in the same manner as in Example 1. The relative density, modulus of elasticity, and internal loss of the dry wood were measured, and the average values ​​were calculated (before treatment in Table 2). The results are shown in Table 2.

[0166] As shown in Table 2, it can be confirmed that by immersing maple (L) and maple (R) in sappanwood extract, the internal loss of maple (L) and maple (R) in an environment of 35°C and 95% relative humidity is reduced.

[0167] Example 21

[0168] As for the wood, except that two sheets of spruce (hereinafter referred to as spruce (L)) with a length of 180 mm in the L direction (fiber direction), a length of 20 mm in the R direction (radial direction), and a thickness of 4.5 mm were used, the modified wood of Example 21 was obtained in the same manner as in Example 3.

[0169] Example 22

[0170] As for the wood, except that two spruce sheets (hereinafter referred to as spruce (R)) with a length of 20 mm in the L direction (fiber direction), a length of 180 mm in the R direction (radial direction), and a thickness of 4.5 mm were used, the modified wood of Example 22 was obtained in the same manner as in Example 4.

[0171] Example 23

[0172] As for the wood, except that two birch (birch wood) sheets with a length of 180 mm in the L direction (fiber direction), a length of 20 mm in the R direction (radial direction), and a thickness of 4.5 mm were used (hereinafter referred to as birch (L)), the modified wood of Example 23 was obtained in the same manner as in Example 3.

[0173] Example 24

[0174] As for the wood, except that two birch leaves (hereinafter referred to as birch (R)) with a length of 20 mm in the L direction (fiber direction), a length of 180 mm in the R direction (radial direction), and a thickness of 4.5 mm were used, the modified wood of Example 24 was obtained in the same manner as in Example 4.

[0175] Example 25

[0176] As for the wood, except that two sheets of beech (Japanese beech) with a length of 180 mm in the L direction (fiber direction), a length of 20 mm in the R direction (radial direction), and a thickness of 4.5 mm were used (hereinafter referred to as beech (L)), the modified wood of Example 25 was obtained in the same manner as in Example 3.

[0177] Example 26

[0178] As for the wood, except that two sheets of beech (hereinafter referred to as beech (R)) with a length of 20 mm in the L direction (fiber direction), a length of 180 mm in the R direction (radial direction), and a thickness of 4.5 mm were used, the modified wood of Example 26 was obtained in the same manner as in Example 4.

[0179] Example 27

[0180] As for the wood, except that two sheets of mahogany (hereinafter referred to as mahogany (L)) with a length of 180 mm in the L direction (fiber direction), a length of 20 mm in the R direction (radial direction), and a thickness of 4.5 mm were used, the modified wood of Example 27 was obtained in the same manner as in Example 3.

[0181] Example 28

[0182] As for the wood, except that two sheets of mahogany (hereinafter referred to as mahogany (R)) with a length of 20 mm in the L direction (fiber direction), a length of 180 mm in the R direction (radial direction), and a thickness of 4.5 mm were used, the modified wood of Example 28 was obtained in the same manner as in Example 4.

[0183] Example 29

[0184] As for the wood, except that two sheets of walnut wood (hereinafter referred to as walnut wood (L)) with a length of 180 mm in the L direction (fiber direction), a length of 20 mm in the R direction (radial direction), and a thickness of 4.5 mm were used, the modified wood of Example 29 was obtained in the same manner as in Example 3.

[0185] Example 30

[0186] As for the wood, except that two sheets of walnut wood (hereinafter referred to as walnut wood (R)) with a length of 20 mm in the L direction (fiber direction), a length of 180 mm in the R direction (radial direction), and a thickness of 4.5 mm were used, the modified wood of Example 30 was obtained in the same manner as in Example 4.

[0187] For each type of wood used in Examples 21 to 30, the mass, relative density of dry wood, modulus of elasticity, and internal loss (before treatment in Tables 3 and 4) were measured in the same manner as in Example 1.

[0188] Furthermore, the cross-sections of the modified wood from Examples 21 to 30 were observed in the same manner as in Example 1. As a result, for each type of modified wood, it was confirmed that the sappanwood extract penetrated to an average depth of 1 mm or more from the surface of the wood.

[0189] In addition, similar to Example 1, the mass of each modified wood from Examples 21 to 30, set to an absolutely dry state (after treatment in Tables 3 and 4), was measured, the rate of change before treatment and its average value were determined, and the mass ratio of the sappanwood extract components was calculated.

[0190] Furthermore, the modified wood samples from Examples 21 to 30, which were set to an absolutely dry state, were conditioned at 22°C and 60% relative humidity until their quality stabilized. The relative density, modulus of elasticity, and internal loss of the dry wood were measured in the same manner as in Example 1, and the rate of change before treatment and their average values ​​were calculated (as shown in Tables 3 and 4). The results are presented in Tables 3 and 4.

[0191] In addition, the results of Examples 3 and 4, which used maple wood, are also shown in Table 3.

[0192] Table 3

[0193]

[0194] Table 4

[0195]

[0196] As shown in Tables 3 and 4, it can be confirmed that by immersing the wood used in Examples 3 and 4, and Examples 21 to 30 in the sappanwood extract, the sappanwood extract is impregnated, thereby reducing internal loss.

Claims

1. A modified wood, characterized in that, It contains wood and sappanwood extract impregnated with said wood. The sappanwood extract is impregnated to an average depth of more than 1 mm from the surface of the wood. The wood impregnated with the extract of sappanwood has an elastic modulus of 7 GPa or more and 20 GPa in the fiber direction, and an elastic modulus of 0.5 GPa or more and 2.5 GPa in the radial direction.

2. The modified wood according to claim 1, characterized in that, The sappanwood extract is not a powdered substance produced by freeze-drying.

3. The modified wood according to claim 1, characterized in that, The internal loss of the wood in the fiber direction is 4×10. -3 Above 12×10 -3 the following, The radial internal loss of the wood is 12 × 10⁻⁶. -3 Above 25×10 -3 the following.

4. The modified wood according to claim 1, characterized in that, The mass of the sappanwood extract is 8% to 12% of the mass of the sappanwood before water extraction.

5. The modified wood according to claim 4, characterized in that, The mass of the water used in the extraction is 10 to 20 times the mass of the sappanwood.

6. A manufacturing method for modified wood, characterized in that, It includes an impregnation process that infuses the wood with sappanwood extract. The sappanwood extract is impregnated to an average depth of more than 1 mm from the surface of the wood. The wood impregnated with the sappanwood extract has a fiber modulus of 7 GPa to 20 GPa and a radial modulus of 0.5 GPa to 2.5 GPa, more preferably 0.8 to 2 GPa.

7. The manufacturing method according to claim 6, characterized in that, Prior to the impregnation process, there is an extraction process in which water is used to extract the sappanwood extract from the sappanwood, and in the extraction process, the sappanwood extract is not pulverized by freeze-drying.

8. The manufacturing method according to claim 6, characterized in that, The internal loss of the wood in the fiber direction is 4×10. -3 Above 12×10 -3 the following, The radial internal loss of the wood is 12 × 10⁻⁶. -3 Above 25×10 -3 the following.

9. The manufacturing method according to claim 7, characterized in that, The mass of the sappanwood extract is 8% to 12% of the mass of the sappanwood before water extraction.

10. The manufacturing method according to claim 7, characterized in that, The mass of the water used in the extraction process is 10 to 20 times the mass of the sappanwood.

11. A musical instrument, characterized in that, The modified wood comprises any one of claims 1 to 5, or modified wood obtained by any one of claims 6 to 10.

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