Methods for processing wood raw materials and wood-based boards

Abstract

This aims to provide a new and useful method for processing wood raw materials, as well as to promote the effective utilization of the core of the wood. [Solution] This method for processing wood raw materials is characterized by comprising a distillation step of distilling wood raw materials to extract a distillate, a separation step of separating the distillate into essential oil and aromatic distilled water, and a reuse step of reusing the residual wood remaining after the distillation step as a raw material for manufacturing wood-based boards. Preferably, the wood raw material used is the peeled core 4 remaining after obtaining veneers 3 continuously with a rotary lathe. The essential oil obtained by this invention can be used for the same purposes as in the conventional method, and the residual wood after essential oil extraction can be reused as a raw material for manufacturing wood-based boards, thereby enabling the effective use of resources.

Description

Technical Field

[0006] , , , ,

[0001] The present invention relates to a method for treating wood raw materials and a wood-based board.

Background Art

[0002] Wood, especially coniferous wood such as Japanese cypress, contains a large amount of phytocides which are fragrance components, and is known to have medical effects such as stress relief, vitality recovery, and improvement of depression. Furthermore, it has also been reported to have effects such as antibacterial, insect-proof, and deodorant.

[0003] As a method for exerting such effects, extracting essential oil from trees such as Japanese cypress is disclosed in Patent Documents 1, 2, etc. below. Patent Document 1 discloses a method for extracting essential oil from a Japanese cypress material composed of a Japanese cypress trunk, Japanese cypress leaves or Japanese cypress fruits. Patent Document 2 discloses a method for extracting essential oil from the rootstock of Japanese cypress.

[0004] By the way, as is well-known and commonly used in the industry, wood-based boards such as MDF (medium density fiberboard) and particle boards are generally manufactured by pulverizing (or further defibrating) wood raw materials such as waste materials remaining in the lumbering or plywood manufacturing process and building demolition materials into chips or wood fibers, forming them into a mat shape by dry or wet forming, and then hot-pressing and forming this mat. [[ID=2,1]]

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, to date, there has been no consideration or implementation of using residual wood remaining after essential oil extraction as a raw material for wood-based boards such as MDF. The chips that have been used as raw materials for wood-based boards such as MDF until now have not had essential oil extracted from them, but research and testing by the inventor has confirmed that there are no inconveniences or problems in using chips after essential oil extraction as a raw material for wood-based boards such as MDF.

[0007] Therefore, the problem that this invention aims to solve is, based on the above findings, to extract essential oils from wood raw materials and to reuse the residual wood after essential oil extraction as a raw material for wood-based boards such as MDF. Another problem that this invention aims to solve is to make effective use of the peeled core that is generated in large quantities during the plywood manufacturing process. [Means for solving the problem]

[0008] To solve these problems, the invention according to claim 1 of this application is a method for processing wood raw materials, characterized by comprising a distillation step of distilling wood raw materials to extract a distillate, a separation step of separating the distillate into essential oil and aromatic distilled water, and a reuse step of reusing the residual wood remaining after the distillation step as a raw material for manufacturing wood-based boards.

[0009] The invention according to claim 2 of this application is a method for processing wood raw materials as described in claim 1, characterized in that the wood raw material used is the peeled core remaining after cutting a log to obtain veneers in a continuous manner.

[0010] The invention according to claim 3 of this application is a method for processing wood raw materials according to claim 1 or 2, characterized in that the wood raw material is a slender, thin, flat pulverized material having dimensions of an average length of 10 to 30 mm, an average width of 3 to 10 mm, and an average thickness of 1 to 2 mm.

[0011] The invention according to claim 4 of this application is a wood-based board that uses residual wood remaining after distilling wood raw materials and extracting the distillate as the raw material. [Effects of the Invention]

[0012] According to the present invention as described in claim 1, essential oils can be extracted from wood raw materials, and the residual wood remaining after essential oil extraction can be reused to manufacture wood-based boards. In other words, wood raw materials can be used as raw materials for essential oil extraction, and the extracted essential oils can be used in the same way as in the conventional method. Furthermore, the residual wood remaining after essential oil extraction can be reused in the manufacture of wood-based boards, either as a standalone material or mixed with other materials, thus demonstrating a significant effect in the effective utilization of resources.

[0013] Furthermore, while oil is generally removed through a steaming process during the manufacture of wood-based boards, depending on the type and part of the wood raw material, it may contain more oil than usual. In such cases, the steaming process may not completely remove the oil, and when the board is hot-pressed, the oil can burn and stick to the press plate, causing the board to adhere. In contrast, according to the present invention, since wood-based boards are manufactured using residual wood from which the oil has been sufficiently removed by essential oil extraction, the oil does not burn and stick to the press plate when hot-pressed, and the wood board does not adhere to the press plate, thus improving productivity. Moreover, since the oil has been sufficiently removed from the residual wood, the time required for the steaming process is shortened, which also contributes to improved productivity.

[0014] According to the present invention as described in claim 2, new uses for peeled cores, which previously had limited applications, are provided, thereby expanding the effective utilization of peeled cores. Furthermore, since peeled cores contain more essential oils than other parts of the log, a high essential oil recovery rate can be obtained by extracting essential oils from peeled cores.

[0015] According to the present invention as of claim 3, by using elongated, thin, plate-shaped pulverized material having an average length of 10 to 30 mm, an average width of 3 to 10 mm, and an average thickness of 1 to 2 mm as the pulverized material obtained in the pulverization process, the essential oil recovery efficiency can be further increased, and the pulverized material can be made to have dimensions that are optimal for use as a raw material for wood-based board manufacturing.

[0016] According to the present invention according to claim 4, since the wood board is manufactured using the residual wood remaining after the essential oil extraction as a raw material, effective utilization of resources can be achieved.

Brief Description of the Drawings

[0017] [Figure 1] It is a flowchart showing the processing method of the wood raw material according to the present invention step by step together with the manufacturing process of the plywood. [Figure 2] It is a side view schematically showing that the peeled core used in the present invention remains after continuously obtaining veneers with a rotary lathe.

Best Mode for Carrying Out the Invention

[0018] The processing method of the wood raw material according to the present invention will be described in detail below with reference to FIGS. 1 and 2 together with the essential oil extraction method.

[0019] (Preparation Step) Prepare logs of coniferous trees such as cypress and cedar, or broad-leaved trees such as eucalyptus and camphor tree. The tree species of the logs is not limited as long as essential oil can be extracted. The logs are, for example, 160 to 500 mm in tree diameter and 2000 to 2150 mm in length.

[0020] A general method for manufacturing plywood is to peel the bark of the log, cut it to a predetermined length (for example, 2000 to 2150 mm), subject it to steaming treatment if necessary (especially in the case of coniferous tree logs), and then cut it into thin veneers (raw veneers) about several millimeters thick in a state of being centered and peeled like a hat with a centering device, dry this to a predetermined moisture content and cut it to a predetermined size, stack them with their fiber directions perpendicular to each other, and press them thermally to manufacture plywood (see FIGS. 1 and 2). However, at the end of cutting the veneers with a rotary lathe, a long cylindrical bar (peeled core) with a diameter of about 50 mm inevitably remains.

[0021] From the perspective of effectively utilizing the stripped cores that remain in large quantities after continuously obtaining veneers from logs using a rotary lathe, it is preferable to extract essential oils using the stripped cores as raw materials. Cutting by a rotary lathe is well-known. As shown in FIG. 1, while rotating the log 1 about its cross-sectional center as an axis, by pressing the cutting edge 2 against the log surface, it cuts in the manner of shaving to continuously produce thin veneers 3. The cross-sectional center that becomes the rotation axis of the log 1 is the center of the inscribed circle calculated based on the data obtained by measuring the cross-sectional shape of the log 1.

[0022] When continuously obtaining veneers in this way using a rotary lathe, finally, a long rod-shaped stripped core 4 remains. From the perspective of yield, it is preferable to make veneers until the diameter of the stripped core becomes as small as possible. On the other hand, as the diameter of the log decreases, the warp of the obtained veneer increases, and the utility value as a veneer is impaired. Therefore, generally, the diameter of the finally remaining stripped core is about 50 to 60 mm, and the length is the same as the log, 2000 to 2150 mm.

[0023] (Grinding process) The peeled cores prepared in the above preparation step are crushed using a crushing means to obtain crushed material. The crushing means is not limited to those that can crush peeled cores, and known cutting machines or crushers such as chippers, shredders, cutter mills (shear-type crushers), and flakers can be used. For example, by feeding a large number of peeled cores together into a chipper and crushing them into chips, roughly rectangular flat crushed material (average length 25-40 mm, average width 25-40 mm, average thickness 3-5 mm) can be obtained. By further crushing this chipped crushed material with a shredder, roughly rectangular flat crushed material with an average length of 20-35 mm, an average width of 3-20 mm, and an average thickness of 3-5 mm can be obtained. Alternatively, by feeding a large number of peeled cores together into a chipper and crushing them into chips, a roughly rectangular, flat material (average length 25-40 mm, average width 25-40 mm, average thickness 3-5 mm) can be obtained. This chipped material can then be further compressed and cut in a cutter mill (shear-type crusher) to grind and crush it, resulting in a long, thin, elongated, flat material with an average length of 10-30 mm, an average width of 3-10 mm, and an average thickness of 1-2 mm. Alternatively, by crushing a large number of peeled cores together in a flaker, a roughly rectangular, thin, flat material with an average length of 50-60 mm, an average width of 50-60 mm, and an average thickness of 1-1.5 mm can be obtained.

[0024] (Distillation process) The pulverized material obtained in the above grinding process is distilled to obtain a liquid distillate (essential oil and water). The processing method in the distillation process is not particularly limited and can be carried out using commonly used distillation equipment. For example, the pulverized material can be heated by steam distillation using heated steam or by hot water distillation by heating and boiling it in water, and the gas produced at that time can be cooled with a cooling device to obtain a distillate consisting of essential oil and water.

[0025] (separation process) The distillate obtained in the above distillation process is separated into essential oil and water. The processing method in the separation process is not particularly limited as long as it can separate the distillate into essential oil and water. For example, by letting the distillate stand for a certain period of time or by performing treatments such as redistillation, the essential oil layer and the water layer can be separated, and the essential oil layer can be recovered from that state. In addition, the water in the distillate is aromatic hydrosol (aroma water) containing trace amounts of essential oil components, so it can be recovered and used in fragrances, cosmetics, etc. If the essential oil and water are automatically separated and recovered during the above distillation process, the separation process can be omitted.

[0026] (Water removal process) Since the essential oil separated and recovered in the above separation process still contains a small amount of water (about 1% of the essential oil), it is preferable to carry out a water removal process in order to remove this water and obtain a high-purity essential oil. The water removal process is not particularly limited as long as it can remove the small amount of water dispersed in the separated essential oil. For example, by cooling the separated essential oil to a temperature below the freezing point of water (0 degrees Celsius) and higher than the freezing point of the essential oil components, only the small amount of water contained in the separated essential oil can be frozen, and the frozen water (ice) can be removed by filtering it in this state. The amount of water contained in the separated essential oil can also be reduced by repeating the distillation process multiple times in the above distillation process, or by letting the distillate stand for a long time in the above separation process, or by separating the essential oil and the small amount of water by centrifugal separation, but the above-mentioned freezing treatment allows for efficient removal of water in a short time. It should be noted that the freezing point of essential oils is difficult to determine definitively due to factors such as tree species, growing environment, and extraction method, as well as the complex mixture of various components with different freezing points, such as α-pinene and limonene. However, it is generally in the range of -20 to -70 degrees Celsius. Therefore, cooling from 0 to -20 degrees Celsius will bring almost all essential oils, even those with varying freezing points, above their freezing point, allowing for an appropriate water removal process.

[0027] The essential oils obtained as described above can be used in various applications (fragrances, cosmetics, antibacterial agents, insect repellents, deodorizers, detergents, aromatherapy, etc.) to exert effects such as stress relief, vitality restoration, improvement of depression, antibacterial properties, insect repellent properties, and deodorizing properties, similar to conventional techniques.

[0028] (Reuse process) The pulverized material remaining after essential oil extraction can be reused either as a standalone material or mixed with other materials in the manufacture of wood fiberboards such as MDF and wood-based boards such as particleboard.

[0029] The present invention will be specifically described below with reference to examples.

[0030] (preparation process) In this example, a cypress log from Shizuoka Prefecture (240 mm in diameter, 2100 mm in length) was used. The log was rotated in a rotary lathe and a cutting blade was applied to the surface to cut it into veneers. After this, many long cylindrical cores (50 mm in diameter, 2100 mm in length) were prepared. The veneer cutting was performed under the following conditions. • Rotary race: Rotation speed 145 m / s • Cutting blade: Length 2200mm, tip thickness 0.5~16mm • Solid wood: 1.85mm thick

[0031] (Grinding process) After cutting the veneers, the remaining cores were put into a chipper in large quantities and crushed into chips, resulting in roughly rectangular, flat chip-like material (average length 25-40 mm, average width 25-40 mm, average thickness 3-5 mm). This was then further compressed and cut in a cutter mill (shear-type crusher) to crush and grind it, yielding 36 kg of elongated, thin cypress wood material with an average length of 20 mm, an average width of 5 mm, and an average thickness of 1.5 mm.

[0032] (Distillation process) The cypress pulverized material obtained in the above grinding process was distilled using a steam distillation apparatus, the discharged steam was collected, cooled in a cooling apparatus, and the distilled water containing cypress essential oil was recovered in a recovery apparatus.

[0033] (separation process) In the distillation process described above, the cypress essential oil-containing distilled water was gradually recovered and left to stand in the recovery apparatus. Due to the difference in specific gravity between the cypress essential oil and water, the upper layer was separated into cypress essential oil and the lower layer into aromatic distilled water. By distilling and separating 36 kg of elongated, thin cypress pulverized material obtained in the grinding process, 450 mL of cypress essential oil and 60 L of aromatic distilled water were obtained.

[0034] (Water removal process) The cypress essential oil separated in the above separation process was cooled to a temperature below the freezing point of water but higher than the freezing point of the cypress essential oil (for example, -18 to -20 degrees Celsius). This froze the water scattered as small bubbles in the cypress essential oil, and the oil was then filtered through a filter (mesh size 126-3) to remove the frozen water (ice), thereby obtaining a high-purity cypress essential oil. Since the dimensions of the removed ice were 0.5 to 2 mm, it was confirmed that by using a filter with a mesh size that allows ice of this size to pass through, it is possible to remove the ice and extract an essential oil with reduced water content and higher purity.

[0035] In the above embodiment, essential oil was extracted from the peeled heartwood remaining after cutting cypress logs into veneers using a rotary lathe. To demonstrate the advantages of using the peeled heartwood as the material for essential oil extraction, the essential oil recovery rate (amount of essential oil extracted per unit weight of raw material) was tested under different extraction conditions. Unless otherwise specified, each process was carried out under the same conditions as described in the embodiment.

[0036] First, in addition to the cypress used in the example, we also conducted a comparative test on the essential oil recovery rate when essential oil was extracted from the peeled heartwood of Japanese cedar (Sugi), and obtained the results shown in Table 1. From these results, it was confirmed that cypress yielded a better essential oil recovery rate than Japanese cedar as a raw wood species.

[0037] [Table 1]

[0038] Next, we conducted a comparative test of essential oil recovery rates when extracting essential oil from different parts of the cypress log, and obtained the results shown in Table 2. From these results, it was confirmed that using the peeled heartwood yielded the best essential oil recovery rate.

[0039] [Table 2]

[0040] Next, we conducted comparative tests on the essential oil recovery rate when extracting essential oil from crushed material obtained by crushing the core of cypress logs, varying the shape and dimensions of the material. The results are shown in Table 3. From these results, we found that the essential oil recovery rate was best when using elongated, thin plate-shaped crushed material obtained by crushing roughly square, flat chip-shaped crushed material with a chipper, and then further compressing, cutting, and grinding it with a cutter mill (shear-type crusher). The best results were obtained using elongated, thin plate-shaped crushed material with an average length of 20 mm, an average width of 5 mm, and an average thickness of 1.5 mm. Based on these results, we further extracted essential oil from crushed material of various dimensions. When essential oil was extracted from elongated, thin plate-shaped crushed material with an average length of 10-30 mm, an average width of 3-10 mm, and an average thickness of 1-2 mm, the essential oil recovery rate was approximately 1% or more, confirming that essential oil can be extracted efficiently.

[0041] [Table 3]

[0042] The reason why the essential oil recovery rate is good when using elongated, thin, plate-shaped pulverized material obtained by further compressing, cutting, and grinding chip-shaped pulverized material obtained by cutting with a chipper is that it has a shape and dimensions that make it easy to extract essential oils, and in the process of further compressing, cutting, and grinding the chip-shaped pulverized material with a cutter mill (shear-type pulverizer), the essential oil is extracted and moves to the surface of the elongated, thin, plate-shaped pulverized material, where it is in a state that is easy to extract, and further cutting the chip-shaped pulverized material obtained by cutting with a chipper (which has a relatively smooth surface) The elongated, thin, plate-like pulverized material obtained by compressing, cutting, and grinding in a termiller (shear-type pulverizer) forms numerous microscopic irregularities on its surface. This increases the surface area of ​​each elongated, thin, plate-like pulverized material that comes into contact with water vapor. Furthermore, water vapor can spread through the voids formed between the irregular surfaces of the elongated, thin, plate-like pulverized material. Additionally, the previously tightly packed wood fibers separate, creating voids that allow water vapor to penetrate not only the surface but also the interior of the woody material. This is presumed to improve the efficiency of recovering cypress essential oil-containing distilled water during the distillation process.

[0043] Although the present invention has been described in detail above with reference to examples and test examples, the present invention can be implemented in a wide variety of ways by modifying or changing it within the scope of the invention as defined by the claims. [Explanation of Symbols]

[0044] 1 Log 2 cutting blade 3. Single-ply 4 Peeled core

Claims

1. A method for processing wood raw materials, characterized by comprising: a distillation step of distilling wood raw materials to extract a distillate; a separation step of separating the distillate into essential oil and aromatic distilled water; and a reuse step of reusing the residual wood remaining after the distillation step as a raw material for manufacturing wood-based boards.

2. A method for processing a wood raw material according to claim 1, characterized in that the core remaining after cutting a log to obtain veneers in a continuous manner is used as the wood raw material.

3. A method for processing a wood raw material according to claim 1 or 2, characterized in that the wood raw material is a slender, thin, flat pulverized material having dimensions of an average length of 10 to 30 mm, an average width of 3 to 10 mm, and an average thickness of 1 to 2 mm.

4. This wood-based board uses residual wood as its raw material after distilling wood and extracting the distillate.

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