Molded body, musical instrument, and musical instrument component

Abstract

A molded body 10 according to one embodiment of the present disclosure includes a plurality of wood pieces 1. The molded body 10 is anisotropic in terms of elastic modulus and strength in the trunk-axis direction of the wood used as a feedstock and in a direction orthogonal to the trunk-axis direction. Fibers 1a of the wood pieces 1 intermingle at the interfaces between the plurality of wood pieces 1.

Description

Molded body, musical instrument and musical instrument part

[0001] The present disclosure relates to a molded body, a musical instrument, and a musical instrument part.

[0002] In woodwind and other musical instruments, the characteristics of the wood have a significant impact on how well it can be played, and wood with defects such as knots and cracks is not suitable for making musical instruments. Meanwhile, the depletion of natural wood resources due to logging and other factors is becoming a serious problem.

[0003] Japanese Patent Publication No. 8-509175 Japanese Patent Publication No. 2019-188648 Japanese Patent Publication No. 2018-196947 Japanese Patent Publication No. 2010-184420

[0004] In light of the depletion of wood resources and other issues, effective utilization of wood has been investigated. Patent Document 1 describes a method of compressing a mixture of wood flour and discontinuous fibers such as carbon under high temperature and pressure to form a cylindrical woodwind instrument tube. Patent Document 2 describes a method of flow molding a precursor obtained by impregnating wood with a thermosetting resin and a lubricant composition. Patent Document 3 describes a method of flow molding a precursor obtained by randomly homogenizing the degree of fiber orientation and densifying the precursor while reducing damage to the fibrous cells inherent in plant-based materials. Patent Document 4 describes a laminated board containing multiple wood materials with fiber lengths of 50 mm or more and an epoxy resin, in which the fiber lengths of the wood materials are aligned in one direction.

[0005] Patent Documents 1 to 3 describe the formation of a molded body with a discontinuous macroscopic interface by flow molding a short fiber material in a mold. However, while the techniques described in Patent Documents 1 to 3 enable the effective use of wood resources, the resulting molded body cannot maintain the anisotropy of the raw material wood, making it difficult to exhibit the original acoustic performance of the raw material wood.

[0006] Patent Document 4 describes a method for forming an acoustic panel by laminating multiple boards with the fiber length direction aligned. However, the technique described in Patent Document 4 tends to limit the parts of the wood that can be used, which is problematic from the perspective of effective utilization of wood resources.

[0007] Musical instruments and instrument parts require high-quality wood that meets requirements for appearance, acoustic performance, etc., and the acoustic properties derived from the anisotropy of the raw wood are particularly important. For example, in woodwind instruments, the performance of the raw materials for the tube body has a significant impact on the playability, and instruments made from natural raw materials are recognized as having high added value.

[0008] The present disclosure is based on these circumstances, and one aspect of the present disclosure aims to provide a molded body that can maintain the anisotropy of wood while making effective use of the wood by making it possible to use parts that have previously been difficult to use.

[0009] (1) A molded body according to one aspect of the present disclosure is a molded body including a plurality of pieces of wood, the molded body having anisotropy in elastic modulus and strength in the direction of the trunk axis of the raw wood material and in a direction perpendicular thereto, and the fibers of the pieces of wood are intertwined at the interfaces between the pieces of wood.

[0010] (2) In the above (1), the texture arrangement of the cross section of the end grain of the plurality of wood pieces may be distorted.

[0011] (3) In the above (2), the distortion may be present at the boundary between the pieces of wood.

[0012] (4) In any of (1) to (3), the plurality of wood pieces are elongated, with the fiber orientation direction corresponding to the trunk axis direction of the raw material wood as the longitudinal direction, and the length of the continuous fiber in the longitudinal direction of the wood pieces is 10 mm or more.

[0013] (5) In any one of (1) to (4) above, the wood chips may be derived from natural wood containing 5% by mass or more of an oil-soluble thermoplastic component.

[0014] (6) In any of (1) to (5) above, the wood chips may be derived from trees of the Fabaceae, Sapotaceae, Lauraceae, or Meliaceae family.

[0015] (7) A musical instrument according to another aspect of the present disclosure uses the molded article according to any one of (1) to (6).

[0016] (8) A musical instrument part according to yet another aspect of the present disclosure uses the molded article according to any one of (1) to (6) above.

[0017] In this disclosure, "the fibers of the wood pieces are intertwined" includes not only a configuration in which the fibers of adjacent wood pieces are entangled, but also a configuration in which the fibers of adjacent wood pieces overlap each other in the radial direction of the fibers, and a configuration in which the fibers of adjacent wood pieces are irregularly intertwined and in contact with each other while maintaining their orientation in the trunk axis direction. "Distortion of the tissue arrangement" means that the tissue arrangement is distorted and bent relative to the original tissue arrangement of the tree. "Continuous fiber length" means the length of the longest unbroken portion of any fiber derived from the raw wood material. In addition, in this disclosure, "tissue arrangement" means the arrangement of tissues such as cell walls in wood, and "fiber" means something formed by a collection of tissues.

[0018] The molded body according to one aspect of the present disclosure allows for the use of previously unusable portions of the wood chips, thereby enabling the effective utilization of raw wood. The molded body has anisotropy in elastic modulus and strength in the direction of the trunk axis of the raw wood chips and in the direction perpendicular to the axis, thereby maintaining and reproducing the mechanical and physical properties of the raw wood chips. Furthermore, the molded body has the wood chips physically bonded together, which inhibits crack propagation and makes the chips less likely to peel.

[0019] FIG. 1 is a schematic perspective view showing a molded body according to an embodiment of the present disclosure. FIG. 2 is a schematic partial enlarged view of the molded body of FIG. 1. FIG. 3 is a schematic partial enlarged view showing the intertwining state of the fibers in the molded body of FIG. 1. FIG. 4 is a schematic partial enlarged view showing the texture arrangement of the butt section of the molded body of FIG. 1. FIG. 5 is an enlarged photograph of a cross section perpendicular to the longitudinal direction of the fibers in the molded body of FIG. 1. FIG. 6 is an enlarged photograph of a cross section perpendicular to the longitudinal direction of the fibers in a conventional molded body. FIG. 7 is an enlarged photograph of the butt section of multiple wood pieces in the molded body of FIG. 1. FIG. 8 is an enlarged photograph of the butt section of a conventional molded body. FIG. 9 is an enlarged photograph of the butt section of a conventional laminated veneer lumber. FIG. 10 is a schematic diagram showing an arrangement step in a manufacturing method for the molded body of FIG. 1. FIG. 11 is a schematic diagram showing a compressed state in the first stage of a first compression step in the manufacturing method for the molded body of FIG. 1. Fig. 12 is a schematic diagram showing a compressed state at a second stage of the first compression step in the method for producing the molded body of Fig. 1. Fig. 13 is a schematic diagram showing the second compression step in the method for producing the molded body of Fig. 1. Fig. 14 is a schematic diagram showing a modified example of the second compression step in the method for producing the molded body of Fig. 1.

[0020] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. It should be noted that with respect to the numerical values ​​described in this specification, only one of the upper and lower limit values ​​described may be adopted, or the upper and lower limit values ​​may be arbitrarily combined. In this specification, all combinable numerical ranges are described as preferred ranges. Furthermore, each figure is a schematic representation and may not correspond to actual dimensions, ratios, etc. In this disclosure, the terms "first" and "second" are used to distinguish the components to which they are attached, and do not limit the number, order, priority, etc.

[0021] [First Embodiment] <Molded Body> FIGS. 1 and 2 show a molded body 10 according to one aspect of the present disclosure. The molded body 10 includes a plurality of wood pieces 1. The molded body 10 has anisotropy in the modulus of elasticity and strength in the trunk axis direction (fiber direction) of the raw wood material and in a direction perpendicular thereto (direction perpendicular to the fibers). As shown in FIGS. 3 and 4 , the molded body 10 has fibers 1a of the wood pieces 1 intertwined at the interfaces between the plurality of wood pieces 1. The shape of the molded body 10 is not particularly limited, and examples thereof include a rectangular parallelepiped, a cylindrical column, and a cylindrical shape. In FIGS. 1 and 2 , the molded body 10 is rectangular parallelepiped. The molded body 10 has a first surface 10a and a second surface 10b facing each other as the planes with the largest area. The molded body 10 may be arranged such that the direction of the trunk axis of the raw wood material (i.e., the trunk axis direction of the tree) is aligned along the first surface 10a or the second surface 10b. In this case, the molded body 10 has anisotropy of the elastic modulus and strength in the direction along the first surface 10a or the second surface 10b and in any direction perpendicular to this direction. The molded body 10 may also have anisotropy of the elastic modulus and strength along the first surface 10a or the second surface 10b and in a direction intersecting the direction in which the trunk axis is arranged. That is, the molded body 10 may have different values ​​of the elastic modulus and strength in two directions perpendicular to the first surface 10a or the second surface 10b. Here, the two perpendicular directions are not particularly limited and can be set to any direction on the first surface 10a or the second surface 10b. However, when the molded body 10 is used as a musical instrument or musical instrument component, it is preferable that the molded body 10 has anisotropy in the longitudinal direction of the first surface 10a or the second surface 10b (the X direction in FIGS. 1 and 2) and in the direction perpendicular to this longitudinal direction (the Y direction in FIGS. 1 and 2).

[0022] Furthermore, when the trunk axis is provided on the first surface 10a or the second surface 10b, the molded body 10 may have anisotropy in a direction intersecting the trunk axis rather than along the first surface 10a or the second surface 10b. For example, when the trunk axis is provided in the X-axis direction of the first surface 10a or the second surface 10b, the molded body 10 may have anisotropy of the elastic modulus and strength in the normal direction of the first surface 10a and the second surface 10b (in other words, the Z direction in Figures 1 and 2). In the above description, the trunk axis and the direction intersecting therewith are defined on the first surface 10a and the second surface 10b in Figures 1 and 2, but they may also be directions on a plane parallel to the first surface 10a or the second surface 10b in Figures 1 and 2. In other words, the molded body 10 has a trunk axis oriented along the first surface 10a, the second surface 10b, or a plane parallel to them, and has anisotropy in elastic modulus and strength in any direction intersecting the trunk axis.

[0023] The anisotropy is based on the fiber orientation direction of the multiple wood pieces 1. The multiple wood pieces 1 constituting the molded body 10 have fibers oriented in one direction as a whole, and the molded body 10 has anisotropy due to this orientation. The fiber orientation direction may be, for example, the longitudinal direction of the molded body 10 (direction along the X direction). By having anisotropy based on the fiber orientation direction, the molded body 10 can have the properties of the raw material wood, or at least approach the properties of the original raw material. Thus, the anisotropy of the elastic modulus and strength in the present disclosure is due to the fiber orientation and is not particularly limited, and may be in any mode such as tension or bending.

[0024] The molded body 10 can easily and reliably reproduce the mechanical and physical properties of the raw wood material by simultaneously satisfying two conditions: maintaining and controlling the anisotropy of wood and realizing a macroscopic discontinuous interface. Maintaining and controlling the anisotropy of wood is effective for maintaining and improving acoustic performance and maintaining material strength, while a macroscopic discontinuous interface is effective for maintaining durability and performance in various usage environments. Here, "macroscopic discontinuous interface" means that the wood piece 1 does not have a clear adhesive interface based on the shape of the raw wood material (wood piece material 11a described below).

[0025] In the present disclosure, the above two conditions can be met by physically bonding multiple pieces of wood 1 having long fibers together so that the fibers are oriented in a specific direction. In this case, as described below, the fibers can be continuous fibers with a length of 10 mm or more.

[0026] In conventional technology, the anisotropy of wood has been maintained by laminating and gluing multiple pieces of wood together while aligning the fiber orientation, as in laminated veneer lumber (LVL) and glued lumber, which use wood veneers as raw materials. However, this technology leaves an adhesive interface in the finished product, which can lead to cracking and peeling starting from the interface. Furthermore, this technology also means that defects in the raw wood materials are inherited in the finished product.

[0027] In addition, in conventional technologies, macroscopic discontinuous interfaces have been achieved by shortening the wood fibers. Specifically, raw wood is ground into powder using a high-speed mill or crusher, and this powdered wood is then compression-molded with an adhesive such as synthetic resin to form macroscopic discontinuous interfaces. This compression molding technology randomly orients the fibers by reducing the grain size of the wood, and then moves the powdered wood to fill the space in the mold, making the adhesive interface between the pieces of wood unclear. However, this technology results in isotropic elastic modulus and strength in the finished product.

[0028] The specific configuration of the molded body 10 will be described below.

[0029] (Wood Pieces) The wood pieces 1 may be elongated pieces with the fiber orientation as the longitudinal direction. As shown in FIG. 2, the longitudinal direction of the wood pieces 1 may be aligned with the longitudinal direction of the molded body 10. The lower limit of the proportion of elongated wood pieces 1 with the fiber orientation as the longitudinal direction among all the wood pieces 1 constituting the molded body 10 may be 50 volume %, 70 volume %, or 80 volume %. On the other hand, the upper limit of the proportion may be 100 volume %. Note that "elongated" means that the length in the longitudinal direction is at least twice the maximum length perpendicular to the longitudinal direction, and this length ratio may be 3 times or more, 5 times or more, 10 times or more, or 15 times or more.

[0030] The size of the wood piece 1 is not particularly limited, but it is preferable that it is appropriately large from the viewpoint of easily and reliably obtaining anisotropy in the elastic modulus and strength in the molded body 10. In other words, the wood piece 1 in the molded body 10 is distinguished from so-called powder-like wood. The lower limit of the cross-sectional area (maximum cross-sectional area) in the direction perpendicular to the longitudinal direction of the fibers in the wood piece 1 is 25 mm ２ It is preferable that the molded body 10 does not exclude the use of powdered wood. However, the lower limit of the proportion of the wood chips 1 among all wood components is preferably 50% by volume, more preferably 70% by volume, even more preferably 90% by volume, and particularly preferably 95% by volume.

[0031] The multiple wood pieces 1 may be elongated, with the fiber orientation direction corresponding to the trunk axis direction of the raw wood as the longitudinal direction. The lower limit of the length of the continuous fibers in the longitudinal direction of the wood pieces 1 is preferably 10 mm, from the viewpoint of maintaining the elastic modulus and strength in the longitudinal direction and improving and controlling the acoustic effect by generating anisotropy with respect to the direction perpendicular to the longitudinal direction. The lower limit of the length may be 50 mm or 100 mm, from the viewpoint of more reliably reproducing the properties of the raw wood. On the other hand, the upper limit of the length is not particularly limited, but may be 500 mm or 300 mm, from the viewpoint of effectively utilizing portions that have previously been difficult to use. The molded body 10 may have a length of the continuous fibers in any one wood piece 1 that is equal to or greater than the lower limit. On the other hand, it is also preferable that the length of the continuous fibers in the multiple wood pieces 1 in the molded body 10 be equal to or greater than the lower limit. In this case, the lower limit of the ratio of the number of wood pieces 1 whose continuous fiber length is equal to or greater than the lower limit value to all wood pieces 1 contained in the molded body 10 is preferably 1 / 2, more preferably 3 / 5, and even more preferably 4 / 5.

[0032] As shown schematically in FIG. 3 , the molded body 10 has the fibers 1a of the wood pieces 1 intertwined at the interfaces between the multiple wood pieces 1. FIG. 3 shows a cross section perpendicular to the longitudinal direction of the fibers 1a. The structure of the interfaces is described in detail below. Adjacent wood pieces 1 are directly bonded to each other through macroscopic defibration of the cellulose-based fiber structure. More specifically, the fibers 1a of one wood piece 1 are bonded to the other wood piece 1 so that the fibers 1a of the other wood piece 1 enter the space created when the wood piece 1 is defibrated. This configuration allows the multiple wood pieces 1 to maintain the orientation of the fibers 1a, while making the interfaces between adjacent wood pieces 1 unclear. At these interfaces, the fibers 1a of adjacent wood pieces 1 maintain their overall orientation, but are intertwined in a position different from the original orientation of the tree. Because the multiple wood pieces 1 are compression-molded with their fibers 1a intertwined in this way, the molded body 10 suppresses defects such as knots and cracks in the raw wood. Furthermore, in the molded body 10, adjacent wood pieces 1 are directly bonded together while making the boundaries unclear, so that even if a small crack occurs due to an environmental change or the like, the propagation of the crack originating from the interface can be suppressed. In other words, the molded body 10 can suppress interfacial fracture between adjacent wood pieces 1.

[0033] 3, adjacent pieces of wood 1 are bonded to each other at their interfaces in a complementary, intricate shape. This shape may be due to distortion of the fibers 1a of the adjacent pieces of wood 1, or may be due to entanglement of the fibers 1a.

[0034] As shown in Fig. 4, the texture arrangement of the cross section of the end grain of the plurality of wood pieces 1 may have a distortion D. This configuration allows adjacent wood pieces 1 to be physically bonded more securely. As a result, it is possible to easily suppress the occurrence and progression of cracks due to environmental changes or external impacts, and it is easier to reproduce the mechanical and physical properties of the raw wood material.

[0035] As shown in Fig. 4, it is preferable that distortion D exists at the boundary portion B between the pieces of wood 1. With this configuration, adjacent pieces of wood 1 are deformed relative to each other while obscuring their boundaries. As a result, it is possible to more reliably suppress the occurrence and progression of cracks due to environmental changes or external impacts.

[0036] The wood pieces 1 may be derived from natural wood containing 5% by mass or more of an oil-soluble thermoplastic component. The lower limit of the content of the thermoplastic component may be 10% by mass or 15% by mass. The thermoplastic component may function as a lubricant that promotes the deformation and flow of the wood pieces 1 when bonding multiple wood pieces 1 together. This makes it easier for the fibers 1a of the wood pieces 1 to intertwine, improving the bonding strength between the wood pieces 1.

[0037] The thermoplastic component refers to a complex compound containing higher fatty acids and lignin-like polymeric compounds having aromatic rings such as benzene rings, among other components excluding cellulose, hemicellulose, and lignin. This thermoplastic component has low reactivity during molding and its chemical properties are unlikely to change before and after molding. Therefore, it improves the bonding strength between the wood pieces 1 while minimizing the impact on the quality of the molded body 10.

[0038] The thermoplastic component is contained in large amounts in the heartwood of a tree, but in small amounts in the sapwood of a tree. Therefore, in the molded body 10, it is also preferable to use the heartwood of a tree as the wood piece 1.

[0039] The wood pieces 1 may be derived from trees of the Fabaceae family, Sapotaceae family, Lauraceae family, or Meliaceae family. All of the wood pieces 1 constituting the molded body 10 may be derived from a single tree selected from the group consisting of Fabaceae, Sapotaceae, Lauraceae, and Meliaceae, or may be derived from two or more trees selected from the group consisting of Fabaceae, Sapotaceae, Lauraceae, and Meliaceae. By deriving the wood pieces 1 from such trees, the content of the thermoplastic component is easily increased. Examples of the Fabaceae trees include trees belonging to the Dalbergia, Pterocarpus, or Caesalpinia genera. Examples of the Fabaceae trees include rosewood, granadilla, wenge, quince, and Pernambuco.

[0040] The molded body 10 can be configured to contain no components other than wood. This configuration makes it easier to reproduce the mechanical and physical properties of raw wood. Meanwhile, the molded body 10 can also contain a synthetic resin in addition to wood components. By including the synthetic resin, the mechanical and physical properties of the molded body 10 can be adjusted. Furthermore, as a secondary effect, the synthetic resin can also function as a binder to bond the wood pieces 1 together. Examples of the synthetic resin include urethane resin and phenolic resin. When the molded body 10 contains a synthetic resin, the content of the synthetic resin in the molded body 10 is preferably less than 15% by mass, from the viewpoint of easily reproducing the mechanical and physical properties of raw wood. Furthermore, the upper limit of the content may be 10% by mass or 5% by mass. In this disclosure, "containing no components other than wood" means that no components other than wood are intentionally added.

[0041] The molded body 10 allows for the effective use of raw wood material by enabling the use of parts that were previously difficult to use as wood chips 1. The molded body 10 has anisotropy in elastic modulus and strength in each direction relative to the orientation direction of the trunk axis of the raw wood material, so it can maintain and reproduce the mechanical and physical properties of the raw wood material. Furthermore, in the molded body 10, the wood chips 1 are physically bonded together, which inhibits the progression of cracks and makes them less likely to peel.

[0042] The advantages of the molded body 10 will be described in detail with reference to Figures 5 to 9. However, the description based on Figures 5 to 9 is not intended to limit the specific configuration of the molded body 10.

[0043] Figure 5 is a cross-sectional photograph of the molded body 10, enlarged 50 times, of a cross section perpendicular to the longitudinal direction of the fibers 110a. Figure 6 is a cross-sectional photograph of the molded body 100, enlarged 50 times, of a cross section perpendicular to the longitudinal direction of the fibers 110a. In a conventional molded body 100 in which wood pieces 110 are bonded together without macroscopic defibration of the fiber structure, the fibers 1a of the wood pieces 1 are intertwined at the interfaces between the multiple wood pieces 1. In the molded body 10, the fibers 1a of adjacent wood pieces 1 overlap or are entangled with each other because the fibers 1a of another wood piece 1 enter the space created when one wood piece 1 is defibrated. In the molded body 10, adjacent wood pieces 1 are directly bonded together while obscuring the boundaries, thereby suppressing the appearance of defects such as knots and cracks in the raw wood. In contrast, as shown in Figure 6, in the conventional molded body 100, the boundaries between adjacent wood pieces 110 are clear, and defects such as knots and cracks in the raw wood material are inherited by the molded body 100. Furthermore, in the conventional molded body 100, the wood pieces 110 are individually separated (the wood pieces 110 are not combined), so that interfacial fracture between adjacent wood pieces 110 is likely to occur.

[0044] FIG. 7 is a 50x magnified cross-sectional photograph of the end grain of multiple wood pieces 1 in the molded body 10. FIG. 8 is a 50x magnified cross-sectional photograph of the end grain of a conventional molded body 200 compression-molded using MDF (medium density fiber board). FIG. 9 is a 50x magnified cross-sectional photograph of the end grain of a laminated veneer lumber 300 in which multiple veneers 310 are laminated and bonded with the same fiber orientation. As shown in FIG. 7, the molded body 10 has distortion D, in which the texture of the end grain cross-section is distorted. This distortion D is also present at the boundary B between the wood pieces 1. From these findings, it can be seen that adjacent wood pieces 1 are deformed, obscuring their boundaries. In contrast, as shown in FIG. 8, the conventional molded body 200 is compression-molded using a small-particle powder and a synthetic resin, making it difficult to align the fiber orientation. Therefore, this molded body 200 does not have anisotropy in elastic modulus and strength, making it difficult to maintain or reproduce the mechanical and physical properties of the raw wood material. Furthermore, as shown in Figure 9, a conventional laminated veneer lumber 300 is made by bonding multiple veneers 310 with an adhesive, so the boundaries between the veneers are clearly defined. Therefore, this laminated veneer lumber 300 is prone to interfacial failure between adjacent veneers 310. Note that, similar to the laminated veneer lumber 300, conventional laminated lumber, which is made by removing defects such as knots and cracks from the raw wood material and processing multiple pieces of wood to a specified size, is also prone to interfacial failure between adjacent pieces of wood, because the boundaries between the pieces are clearly defined.

[0045] <Musical Instrument> A musical instrument using the molded article 10 is one aspect of the present disclosure. The musical instrument may be, for example, an acoustic instrument such as a woodwind instrument, a percussion instrument, a string instrument, or a keyboard instrument. In the musical instrument, the molded article 10 may be processed into a desired shape for the musical instrument.

[0046] This instrument makes effective use of the raw wood material while maintaining and reproducing the mechanical and physical properties of the raw wood material. In addition, the wooden pieces 1 of this instrument are physically bonded together, which prevents cracks from progressing and makes them less likely to peel off.

[0047] <Musical Instrument Component> A musical instrument component using the molded article 10 is one aspect of the present disclosure. The musical instrument component may be, for example, a component for a woodwind instrument, a component for a percussion instrument such as a xylophone or marimba, a component for a stringed instrument such as a guitar fingerboard or bridge, or a component for a keyboard instrument such as a piano keyboard or action part. In the musical instrument component, the molded article 10 may be processed into a desired shape for the musical instrument component.

[0048] The musical instrument part can effectively utilize the raw wood material while maintaining or reproducing the mechanical and physical properties of the raw wood material. Furthermore, the wooden pieces 1 of the musical instrument part are physically bonded together, which inhibits the progression of cracks and makes them less likely to peel off.

[0049] <Manufacturing Method> Next, an example of a method for manufacturing the molded body 10 will be described with reference to FIGS.

[0050] The manufacturing method of the molded body (hereinafter also referred to simply as "the manufacturing method") involves placing the original material of the wood piece 1 (wood piece material 11a) in the cavity 20a of the mold 20 (placement step S1), compressing the wood piece material 11a placed in the cavity 20a (first compression step S2), and re-compressing the pre-molded body 11 formed by compression (second compression step S3).

[0051] 10, in the arrangement step S1, a plurality of wood pieces 11a are arranged in the cavity 20a of the mold 20. In the arrangement step S1, these wood pieces 11a are arranged so that the orientation direction of the fibers in the plurality of wood pieces 11a is the same.

[0052] The size of the wood chip material 11a in the arrangement step S1 can be within the same range as the size of the wood chip 1 described above in the molded body 10. In addition, the abundance ratio of the wood chip material 11a having the above size can be within the same range as the abundance ratio described above in the molded body 10.

[0053] (First Compression Step S2) In the first compression step S2, as shown in FIGS. 11 and 12 , the plurality of wood pieces 11a arranged in the cavity 20a are compressed in a direction perpendicular to the fiber orientation direction. In the first compression step S2, temperature and compression pressure are applied to the wood pieces 11a while utilizing the viscosity and temperature dependence of the thermoplastic component contained in the wood pieces 11a. Alternatively, in the first compression step S2, the synthetic resin may be added to the wood pieces 11a, and the viscosity and temperature dependence of the synthetic resin may be utilized instead of or in addition to the thermoplastic component. For example, applying the synthetic resin to the surfaces of the plurality of wood pieces 11a can improve the moldability and mechanical properties of the wood pieces 11a.

[0054] In the first compression step S2, the plurality of wood chips 11a are plastically deformed in a direction perpendicular to the fiber orientation direction (hereinafter simply referred to as the "vertical direction"). Furthermore, in the first compression step S2, the wood tissue network, with cellulose as the main axis, of the plurality of wood chips 11a is temporarily defibrated in the fiber orientation direction (hereinafter also referred to as the "unit orientation direction"). When compressive stress is applied in the vertical direction in the plurality of wood chips 11a, the compressive stress compresses each tissue, and then plastically deforms the plurality of wood chips 11a in the vertical direction. However, this deformation is difficult to occur in the orientation direction. In the first compression step S2, the plurality of wood chips 11a are plastically deformed in the vertical direction, and fibers from other wood chips 11a are inserted to fill spaces between fiber units created by macroscopic defibration of the fiber structure in the orientation direction during this process. In the plurality of wood chips 11a, the wood fibers maintain their pre-defibration state even after macroscopic defibration. Therefore, by allowing the fibers of another wood piece material 11a to enter the space created by macroscopic defibration, the interface between adjacent wood piece materials 11a can be made unclear while maintaining the fiber orientation direction for multiple wood piece materials 11a.

[0055] In the first compression step S2, as shown in Fig. 11, the plurality of wood pieces 11a are first pressed in one direction perpendicular to the fiber orientation, compressing the plurality of wood pieces 11a in the pressing direction and causing them to flow in a direction perpendicular to the pressing direction and perpendicular to the fiber orientation direction. As the pressing continues in the first compression step S2, the plurality of wood pieces 11a continue to undergo plastic flow deformation so as to fill the voids in the cavity 20a, as shown in Fig. 12. This pressing homogenizes the pressure applied to the plurality of wood pieces 11a. Even during this process, the contact points between the plurality of wood pieces 11a are maintained unchanged.

[0056] The compression temperature in the first compression step S2 may be, for example, 120° C. or higher and 200° C. or lower. The compression pressure in the first compression step S2 may be, for example, 30 MPa or higher and 50 MPa or lower.

[0057] In this manufacturing method, a steaming treatment may be performed as a pretreatment for the first compression step S2 to decompose the hemicellulose contained in the wood chips 11a. This reduces the vertical elastic modulus of the multiple wood chips 11a in a high-temperature environment of about 130°C to 200°C. As a result, the plastic deformation region expands and the stress at the start of deformation can be reduced.

[0058] (Second Compression Step S3) In the second compression step S3, as shown in Fig. 13, the pre-molded body 11 compression-molded in the first compression step S2 is re-compressed in a direction different from the compression direction in the first compression step S2. In the second compression step S3, the pre-molded body 11 is re-compressed, for example, from a direction rotated 90° with respect to the compression direction in the first compression step S2. The re-compression direction is not particularly limited, and may be, for example, a direction parallel to or perpendicular to the fiber orientation direction in the pre-molded body 11. The pre-molded body 11 after compression in the second compression step S3 is configured as the molded body 10 in Fig. 1.

[0059] In the second compression step S3, the pre-molded body 11 compression-molded in the first compression step S2 is re-compressed to homogenize the pressure applied to the pre-molded body 11. In the second compression step S3, the pre-molded body 11 may be repeatedly compressed while changing the compression angle until the pressure applied to the pre-molded body 11 is sufficiently homogenized. For example, in the second compression step S3, compression from a compression direction rotated 90° from the compression direction in the first compression step S2 and compression from the compression direction in the first compression step S2 may be alternately repeated. Furthermore, in the second compression step S3, as shown in FIG. 14, multiple pre-molded bodies 11 may be placed in the cavity 20a of the mold 20, and compression pressure may be applied to these pre-molded bodies 11 simultaneously. In this manner, a single molded body 1 having multiple pre-molded bodies 11 as components can be manufactured.

[0060] In the second compression step S3, the contact points between the plurality of wood pieces 11a are shifted with each compression, so that by compressing the pre-molded body 11 multiple times in the second compression step S3, it is possible to apply pressure uniformly to all of the wood pieces 11a.

[0061] The fiber structure of the wood chip material 11a to which compressive stress is uniformly applied is maintained with macroscopically defibrated wood fibers as the smallest unit. Therefore, the wood chip material 11a is in a state where the wood fibers are physically entangled with spaces between the fibers. When the pre-molded body 11 is further compressed from this state, the macroscopically defibrated fibers flow to fill the spaces between the fibers while building a physical network. As a result, each wood chip material 11a does not have the interface that existed when it was placed in the cavity 20a, and the cross section of the molded body does not have a continuous interface.

[0062] The compression temperature in the second compression step S3 may be the same as the compression temperature in the first compression step S2. The compression pressure in the second compression step S3 may be the same as the compression pressure in the first compression step S2.

[0063] The wood pieces 1 in the molded body 10 formed by the second compression step S3 do not retain the shape of the wood piece material 11a placed in the cavity 20a in the placement step S1. However, the wood pieces 1 in this molded body 10 have the same orientation as the wood piece material 11a when placed in the cavity 20a. At this time, the physicochemical structure of the wood (the arrangement of cellulose, hemicellulose, and lignin, and the arrangement of wood cells) inherits the wood structure before molding at a macro level, and the mechanical and physical properties of the raw wood material are inherited.

[0064] [Other Embodiments] The above-described embodiments do not limit the configuration of the present invention. Therefore, the above-described embodiments may include omissions, substitutions, or additions of components based on the description in this specification and common general technical knowledge, and all of these should be construed as falling within the scope of the present invention.

[0065] In the molded body, the wood pieces can be physically bonded together because the fibers of the wood pieces are intertwined at the interfaces between them. Therefore, if the desired bonding strength can be obtained in the molded body, it is possible to adopt a configuration in which the texture arrangement of the wood pieces does not have distortion. Furthermore, even if the distortion is present, this distortion does not have to be present at the boundaries between the wood pieces.

[0066] The plurality of wood pieces are elongated, with the fiber orientation direction corresponding to the trunk axis direction of the raw wood material as the longitudinal direction, which makes it easy to maintain and reproduce the mechanical and physical properties of the raw wood material. However, during the manufacturing process of the molded product, the wood pieces tend to flow in a direction perpendicular to the fiber orientation direction. Therefore, for example, by utilizing this fluidity, it is possible to adjust the shape of the plurality of wood pieces.

[0067] The molded product can maintain and reproduce the mechanical and physical properties of the raw wood material, and can therefore be used for various components that require the properties of the raw material, and can therefore be used for purposes other than musical instruments.

[0068] The molded body may be produced by a method other than the above-mentioned production method.

[0069] 1 Wood piece 1a Fiber 10 Molded body 10a First surface 10b Second surface 11 Pre-molded body 11a Wood piece material 20 Mold 20a Cavity 100 Molded body 110 Wood piece 110a Fiber 200 Molded body 300 Laminated veneer material 310 Veneer B Boundary portion between wood pieces D Strain

Claims

1. A molded body comprising a plurality of wood pieces, said molded body having anisotropy of elastic modulus and strength in the direction of the trunk axis of the raw wood material and in a direction perpendicular thereto, and wherein the fibers of the wood pieces are intertwined at the interfaces between the plurality of wood pieces.

2. The molded product according to claim 1, wherein the texture arrangement of the cross section of the end grain of the plurality of wood pieces is distorted.

3. The molded product according to claim 2, wherein the distortion exists at the boundary between the pieces of wood.

4. The molded body according to claim 1, wherein the plurality of wood pieces are elongated with the fiber orientation direction corresponding to the trunk axis direction of the raw wood material, and the length of the continuous fibers in the longitudinal direction of the wood pieces is 10 mm or more.

5. The molded body according to claim 1, wherein the wood chips are derived from natural wood containing 5% by mass or more of an oil-soluble thermoplastic component.

6. The molded body according to claim 1, wherein the wood chips are derived from trees of the Fabaceae, Sapotaceae, Lauraceae or Meliaceae family.

7. A musical instrument using the molded article according to any one of claims 1 to 6.

8. A musical instrument part using the molded article according to any one of claims 1 to 6.

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