Fiberboard manufacturing method

Abstract

Provided is a fiber board production method with which it is possible to improve the strength of a fiber board and which also enables improvement in transportability and storage property of a woody material which is a raw material. This fiber board production method involves: adding an adhesive to woody fibers obtained by steam-boiling and then defibrating a woody material, and forming and hot press-molding the resulting woody fibers. The woody material includes folded divisional compact products 1. The folded divisional compact products 1 are obtained by grinding palm plants into chips that are of anisotropic lengths, laminating the thus-obtained ground product 2 to form a mat 3, compressing the mat 3 in the thickness direction to form a planar compact product 4, and folding and dividing the planar compact product 4.

Description

[Technical Field]

[0001] The present disclosure relates to a method for making a fiber board, and more particularly to a method for making a fiber board that includes wood-based materials. [Background technology]

[0002] Patent Document 1 describes the production of a wood fiberboard using wood fibers obtained by steaming and defibrating wood chips.

[0003] Patent Document 2 describes the production of fiberboard using wood fibers obtained from oil palm.

[0004] In recent years, tropical wood has been on a global decline, and as a substitute, fiberboards using wood fibers obtained from palm plants have been proposed. However, even when the manufacturing method described in Patent Document 1 is applied to palm plants, it is sometimes difficult to obtain the desired strength and surface smoothness. Furthermore, even when wood fibers obtained from oil palms are used, as in Patent Document 2, there is a demand for improved fiberboard performance. That is, when manufacturing fiberboards such as the above-mentioned wood fiberboards and fiberboards, there is a demand for improved strength of the resulting fiberboard. There is also a demand for improved transportability and storage of the raw material wood fibers. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-052514 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-069670 Summary of the Invention

[0006] An object of the present disclosure is to provide a method for manufacturing a fiber board that can improve the strength of the fiber board and also improve the transportability and storage properties of the wood material that is the raw material.

[0007] A fiberboard manufacturing method according to one embodiment of the present disclosure includes steaming and defibrating a wood material to obtain wood fibers, adding an adhesive to the resulting wood fibers, and then forming and thermo-compressing the wood material. The wood material includes a broken and compressed product. The broken and compressed product is obtained by crushing a palm plant into chips with anisotropy in length, stacking the chips to form a mat, compressing the mat in the thickness direction to form a plate-like compressed product, and folding and dividing the plate-like compressed product. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view showing the steps of producing a broken and compressed product in the method for producing a fiber board according to this embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a plate-shaped compressed product in the method for producing a fiber board according to this embodiment. [Figure 3] Fig. 3A is a schematic diagram showing a pellet-shaped compressed product in a reference example of this embodiment, and Fig. 3B is a schematic diagram showing a plate-shaped compressed product in the fiber board manufacturing method according to this embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a plate-shaped compressed product of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Embodiment 1) (1) Overview The process leading to the method for manufacturing a fiber board according to this embodiment will be described below.

[0010] The current global wood board market is worth more than 10 trillion yen per year, and in parallel with the growing issue of global environmental issues, further market expansion and demand are predicted for the future. As a result, the tropical woods that have been used traditionally, such as lauan, are depleted resources that take more than 50 years to grow, so there is a growing need for technology to utilize alternative materials.

[0011] There are several types of wood boards, including laminated wood, which is primarily used for structural and formwork applications; chipboard, which is used for underlayment and as furniture material; and fiberboard, which is widely used for interior components and furniture surfaces. Technologies for utilizing low-quality wood, such as small diameter trees and fast-growing planted trees with short felling periods, have been developed as alternatives to these depleted resources, and are now widely used around the world. However, with further increases in usage and a decrease in the global area of ​​afforestation, it is expected that these materials will gradually become more difficult to procure.

[0012] Fiberboards, in particular, can be manufactured using only fibrous materials, rather than wood chips of a certain shape. For this reason, many efforts have been made in the past to develop technologies for utilizing grass plants such as bamboo, straw, and bagasse, which have strong bast fibers, as well as mallow plants such as kenaf and jute, as future material technologies. However, these have not been widely put to practical use due to issues in terms of quality, manufacturing, and raw material procurement.

[0013] In this context, palm trees such as oil palms and coconut palms, which are widely distributed, mainly in tropical regions, are attracting attention as a source of raw materials with large accumulations. With the growth of the palm oil industry, large amounts of oil palm trunks (OPT: Oil Palm Trunk) and empty fruit bunches (EFB: Empty Fruit Bunch) are being discarded, with over 50 million tons of this waste generated annually in Malaysia, a palm oil-producing country. Furthermore, leaving these wastes unattended releases over 1 million tons of methane gas annually. When converted into carbon dioxide emissions, this amounts to approximately 10% of the country's carbon dioxide emissions, making it a currently extremely serious social issue.

[0014] The annual global use of fiberboard is 150 million tons, so even just the 50 million tons that are discarded represents an enormous accumulation, or about one-third of the world's total. However, because palm trees have a moisture content of around 70-300%, more than twice that of regular tropical wood, green wood rots within one to two weeks, making storage extremely difficult.

[0015] Furthermore, the apparent specific gravity of typical palm trees in their green state is around 0.60 to 0.80, but after drying, the specific gravity drops to around 0.35. Therefore, when transporting green wood, the amount of material obtained is about half of the mass actually transported, which is an issue. Furthermore, when transporting dried material to a fiberboard manufacturing plant for use, the bulk density becomes too low during transportation, which increases the number of transports and reduces transportation efficiency.

[0016] Furthermore, although the fiber portion of palm plants is rigid, it contains approximately 40% by mass of parenchyma cells, which are fine particles with a diameter of less than 0.5 mm. When fiberboards are typically produced using conventional methods using palm plants as raw materials, the palm plant fine particles can cause issues such as reduced productivity during board production, such as clogging of cutting tools, poor drying, and quality variations. Furthermore, because the palm plant fine particles do not contribute to the development of strength, there is also the issue of not being able to ensure sufficient strength performance of the fiberboard.

[0017] Due to the above issues, palm trees have hardly been put to practical use in fiberboard applications, and currently, most oil palm waste is left abandoned and discarded locally, which remains a social issue.

[0018] Therefore, in this embodiment, it is possible to obtain fiberboards made from waste palm plants, and at the same time, a biomass fiberboard is provided that can be used as a fiberboard substitute in the future global market, thereby realizing stable procurement.Furthermore, this embodiment provides a biomass fiberboard that can aim to solve social issues in Southeast Asia.

[0019] That is, in the method for manufacturing a fiberboard according to this embodiment, first, an adhesive is added to wood fibers obtained by steaming and defibrating a wood material. Next, the wood fibers to which the adhesive has been added are formed. Next, the formed wood fibers are thermocompressed. The wood material includes a broken and compressed product 1. The broken and compressed product 1 is obtained as follows: First, a palm plant is pulverized into chips having anisotropy in length. Next, crushed material 2 of the palm plant is layered to form a mat 3. Next, the mat 3 is compressed in the thickness direction to form a plate-shaped compressed product 4. Next, the plate-shaped compressed product 4 is folded and divided to obtain the board.

[0020] The method for manufacturing a fiberboard according to this embodiment uses a broken and compressed product 1 obtained by compressing a pulverized material 2 of a palm plant. The broken and compressed product 1 is a compressed biomass product, and the fibrous tissue of the palm plant is less susceptible to compression damage. The broken and compressed product 1 is also less susceptible to decay, improving storage properties. Since a fiberboard is manufactured using the broken and compressed product 1, whose fibrous tissue is less susceptible to damage and decay, a fiberboard with excellent strength and surface smoothness is more easily obtained. Furthermore, in manufacturing the broken and compressed product 1, the plate-shaped compressed product 4 is broken by folding rather than being cut with a blade. Therefore, the wood fibers contained in the broken and compressed product 1 are less likely to shorten and are less likely to break, allowing for an increase in the amount of relatively long wood fibers. This improves the strength of a fiberboard obtained from a wood material containing the broken and compressed product 1. Furthermore, since the compressed material 4 can be stored and transported in the state of a plate before being folded and divided (hereinafter sometimes referred to as "breaking"), the bulk density during storage and transportation is higher than that of pellet-shaped wood material produced by extrusion molding into a cylindrical shape, for example, and storage and transportation properties are improved.

[0021] (2) Details <Broken compressed material> The broken and compressed material 1 used in this embodiment is a biomass compressed material, which is a compressed material including pulverized material 2 of a palm plant. That is, the broken and compressed material 1 is made from renewable biological resources (palm plant) by using palm cuttings and crushed pieces, which are the pulverized material 2 of a palm plant, as raw materials, drying them, and then compressing them. The broken and compressed material 1 has a higher bulk density than when the pulverized material 2 of a palm plant is not compressed, and therefore has improved transportability.

[0022] The type of palm plant used for the broken and compressed material 1 is not particularly limited, but may be oil palm, borage palm, coconut palm, date palm, sago palm, acai, palm grove, etc. Also, the parts that can be used are not particularly limited, but may be trunk (OPT), leaf part (OPF: Oil Palm Frond), fruit part, bunch part (EFB), seed part, etc.

[0023] Palm plants are crushed and dried, and then compressed. The order of crushing and drying may vary, or they may be carried out simultaneously. The method for crushing palm plants is not particularly limited, but it can be carried out using a chipper, for example. Drying the crushed material to a moisture content of 25% by mass or less is preferable, as this can prevent the progression of decay. After crushing the palm plants, washing them with water to reduce the ash content is preferable, as this can reduce the occurrence of process problems caused by ash in the steaming process described below.

[0024] The palm plant pulverized material 2 is obtained by pulverizing the above-mentioned usable parts of a palm plant into chips. The palm plant pulverized material 2 preferably contains vascular tissue of a palm plant. The vascular tissue of a palm plant is tissue that transports water and nutrients necessary for the growth of a palm plant, and includes xylem, phloem, and fiber. The xylem is a pathway for transporting water and nutrients absorbed from the roots. The phloem is a pathway for transporting nutrients created by the leaves, and has phloem tubes.

[0025] The ground material 2 of the palm plant is formed into chips having anisotropy in length. Here, "chips having anisotropy in length" means that the ground material 2 is not spherical. For example, if the length, width, and thickness of the ground material 2 are different, it can be said that the ground material 2 is in chip form having anisotropy in length. Also, for example, if the ground material 2 is formed into a fibrous shape, the length of the ground material 2 is larger than the diameter of the ground material 2, and therefore it can be said that the ground material 2 is in chip form having anisotropy in length.

[0026] The broken and compressed material 1 contains a plurality (numerous) of pulverized materials 2 of palm family plants, and each pulverized material 2 has a variety of sizes. However, it is preferable that the pulverized materials 2 of palm family plants constituting the broken and compressed material 1 contain a large number of pulverized materials 2 having a predetermined length and diameter. Specifically, it is preferable that pulverized materials 2 having a length of 0.8 mm to 50.0 mm and a diameter (diameter) of 0.10 mm to 2.00 mm account for 70% or more by mass of the total amount of pulverized materials 2 contained in the broken and compressed material 1. If the pulverized materials 2 having such a predetermined length and diameter account for less than 70% by mass of the total amount of pulverized materials 2 contained in the broken and compressed material 1, the fiber component that contributes to the development of strength in the fiber board of this embodiment will be reduced, and the strength of the fiber board will be likely to decrease. In addition, because the proportion of palm family plant parenchyma tissue, which is the main component of the fine powder, is increased in the pulverized palm plant material, it may be more likely to cause blade clogging, poor drying, and quality variations, making it difficult to consistently produce fiber boards. It is more preferable that the pulverized palm plant material 2 having a length in the range of 1.0 mm to 50.0 mm and a diameter in the range of 0.10 mm to 2.00 mm accounts for 80% or more by mass of the total amount of pulverized palm plant material 2, and most preferably 100%.

[0027] The length and diameter of the crushed palm plant material can be obtained by photographing a predetermined amount of crushed material and measuring the length and diameter.

[0028] The pulverized material 2 contained in the broken and compressed material 1 is preferably obtained by pulverizing an Arecaceae plant and then classifying it to reduce the amount of Arecaceae plant parenchyma tissue. In other words, the Arecaceae plant pulverized material 2 includes small pulverized materials whose main component is Arecaceae plant parenchyma tissue and large pulverized materials whose main component is Arecaceae plant vascular tissue, and it is preferable to have fewer of these small pulverized materials. Arecaceae plant parenchyma tissue is tissue composed of the parenchyma cells of Arecaceae plants. Arecaceae plant parenchyma tissue contains assimilation tissue, secretion tissue, storage tissue, etc., and has physiological functions such as synthesis, decomposition, and storage.

[0029] If the broken and compressed material 1 contains a large amount of palm family plant parenchyma tissue, it may be difficult to stably produce fiberboards because the palm family plant parenchyma tissue is a fine powder. Therefore, in this embodiment, the amount of palm family plant parenchyma tissue is reduced in order to obtain a palm family plant pulverized material 2 with a low content of palm family plant parenchyma tissue.

[0030] The specific gravity of the broken and compressed product 1 is within the range of 0.35 or more and 1.50 or less. If the specific gravity of the broken and compressed product is less than 0.35, the mechanical durability of the broken and compressed product 1 decreases, making it more likely to break or crack during transportation. If the specific gravity of the broken and compressed product 1 is greater than 1.50, the fibrous tissue constituting the palm plant pulverized material 2 may be damaged by compression, making the strength characteristics of the final fiber board more likely to decrease. To improve transportability, the specific gravity of the broken and compressed product 1 is more preferably within the range of 0.40 or more and 1.50 or less. The specific gravity of this broken and compressed product 1 can be adjusted by changing the compression force used when producing the compressed product 4, which will be described later.

[0031] The moisture content of the broken and compressed material 1 is preferably 25% by mass or less, and more preferably 20% by mass or less. If the moisture content is higher than 25% by mass, the shape retention of the broken and compressed material 1 is likely to decrease, and at the same time, it is more likely to spoil, which also reduces storage properties. There is no particular lower limit for the moisture content of the broken and compressed material 1, but considering storage properties, a lower moisture content is preferable, so the lower limit is 0% by mass. The moisture content of this broken and compressed material 1 can be adjusted by changing the drying temperature and drying time of the pulverized material 2 or its raw wood.

[0032] The size of the broken compressed product 1 (the size of the pieces obtained by folding the compressed product 4) is preferably 8 mm to 25 mm in width, 10 mm to 50 mm in length, and 8 mm to 25 mm in thickness. This allows the fiberboard to be manufactured using equipment similar to that conventionally used for manufacturing medium-density fiberboard.

[0033] <Method of manufacturing the broken and compressed product> To produce the broken and compressed product 1, first, an Arecaceae plant is pulverized into chips with anisotropy in length to obtain a plurality (numerous) of pulverized materials 2. As described above, it is preferable that the pulverized materials 2 have a low content of Arecaceae plant parenchyma cell tissue, and therefore it is preferable to reduce the amount of Arecaceae plant parenchyma cell tissue. As a method for reducing the amount of Arecaceae plant parenchyma cell tissue, a method of classifying to remove small sized pulverized material can be used. Methods of classification include sieving, air sorting, and water bathing, but are not particularly limited thereto.

[0034] Next, a plurality of pulverized materials 2 are stacked to form a mat 3. As shown in FIG. 1, the mat 3 can be formed by stacking a plurality of pulverized materials 2 on a conveyor belt 60. At this time, since the pulverized materials 2 have anisotropy in length, their long axis direction tends to be aligned horizontally. Furthermore, if the pulverized materials 2 are fibrous, the mat 3 may be formed by aligning their long axis direction.

[0035] Next, the mat 3 is compressed in the thickness direction to form a plate-like compressed product 4 containing a plurality of pulverized materials 2. To compress the mat 3 in the thickness direction, the mat 3 is passed between a pair of rolls 61 facing each other from above and below, and compressed by sandwiching the mat 3 between the pair of rolls 61. To pass the mat 3 between the pair of rolls 61, the pair of rolls 61 are rotated while the conveyor belt 60 is advanced in a direction perpendicular to the axial direction of the rolls 61, so that the mat 3 is conveyed by the conveyor belt 60. Because the gap between the pair of rolls 61 is smaller than the thickness of the mat 3, the mat 3 is compressed.

[0036] The thickness of the mat 3 and the plate-shaped compressed material 4 is not particularly limited, but for example, the thickness of the mat 3 can be 8 mm or more and 50 mm or less, and the thickness of the plate-shaped compressed material 4 can be 5 mm or more and 30 mm or less.

[0037] When compressing the pulverized material 2, no adhesive is used and the material is integrated by compressive force, but adhesive may be used to the extent that it does not interfere with defibrating the wood material. Furthermore, functional materials such as antibacterial agents, fragrances, and colorants may be mixed into the pulverized material 2 and integrated into it. In this case, these functions can be imparted to the resulting fiber board, which is preferable.

[0038] In this embodiment, grooves 40 are formed in the plate-shaped compressed material 4. As shown in FIG. 1 , the plate-shaped compressed material 4 has a plurality of grooves 40, some of which are formed so as to extend parallel to the longitudinal direction of the plate-shaped compressed material 4. In addition, other parts of the plurality of grooves 40 are formed so as to extend in a direction perpendicular to the longitudinal direction of the plate-shaped compressed material 4. The longitudinal direction of the plate-shaped compressed material 4 is the same as the conveying direction of the mat 3 and the plate-shaped compressed material 4 by the conveyor belt 60.

[0039] The grooves 40 can be formed, for example, by providing a plurality of protrusions on the peripheral surfaces of a pair of rolls 61 and pressing these protrusions against the surface of the plate-shaped compressed material 4. In this case, the grooves 40 can be formed in the same process as molding the plate-shaped compressed material 4 from the mat 3. With protrusions that are long in the axial direction of the rolls 61, grooves 40 that extend in a direction perpendicular to the longitudinal direction of the plate-shaped compressed material 4 can be formed. With protrusions that are long in the circumferential direction of the rolls 61, grooves 40 that extend parallel to the longitudinal direction of the plate-shaped compressed material 4 can be formed.

[0040] As shown in FIG. 2 , grooves 40 are provided on both the top and bottom surfaces of the plate-shaped compressed product 4. The grooves 40 on the top surface of the plate-shaped compressed product 4 and the grooves 40 on the bottom surface are formed to face each other in a one-to-one relationship. The plate-shaped compressed product 4 is then folded and divided into multiple pieces to obtain a broken compressed product 1. By folding the plate-shaped compressed product 4 along the grooves 40, stress tends to concentrate in the area between the opposing grooves 40, making it easy to divide. The divided broken compressed product 1 is a compressed product containing a crushed palm plant 2. The broken compressed product 1 is formed into a block, plate, or other shape. When folding and dividing the plate-shaped compressed product 4, methods such as crushing with a three-point roll, an embossing roll, or a simple crusher can be used.

[0041] As described above, in this embodiment, when producing the broken and compressed product 1, the plate-shaped compressed product 4 is not cut but is instead broken (folded and divided). Therefore, the palm family plant fibers in the plate-shaped compressed product 4 are less likely to be cut. As a result, the palm family plant fibers contained in the broken and compressed product 1 are less likely to become short, and the palm family plant fibers contained in the broken and compressed product 1 are more likely to be oriented in the length direction, making them less likely to break, and it is possible to increase the amount of relatively long fibers in the broken and compressed product 1. Therefore, the strength of the fiber board obtained by molding a wood material containing the broken and compressed product 1 is improved.

[0042] Furthermore, in this embodiment, the compressed product 4 can be stored and transported in the plate-like state before being broken, which increases the bulk density during storage and transport, improving storage and transportability. For example, pellets P produced by cylindrically extruding pulverized palm plant material 2 as shown in FIG. 3A have a bulk density of 0.3 to 0.4, whereas the compressed product 4 in the plate-like state as shown in FIG. 3B has a bulk density of 0.8 to 0.9. Therefore, in this embodiment, the compressed product 4 can be stored and transported in a smaller volume than when it is stored and transported as pellets P. Therefore, it is preferable to store and transport the compressed product 4 in the plate-like state before being broken.

[0043] <Manufacturing method of fiberboard> In the fiber board manufacturing method according to this embodiment, a wood material is steamed and defibrated to obtain wood fibers, to which an adhesive is added, and the resulting material is then formed and thermo-compressed. The wood material contains one or more broken and compressed materials 1. By using the broken and compressed materials 1, the fiber board manufacturing method according to this embodiment can easily produce boards of consistent quality, even when palm trees with low bulk density are used.

[0044] The wood material may contain only the broken and compressed material 1, or may contain other wood materials, such as crushed tropical wood or coniferous wood, which have traditionally been used in the production of medium-density fiberboard. The broken and compressed material 1 derived from palm trees contained in the wood material preferably accounts for 20% or more by mass of the total amount of the wood material. This allows for the effective use of oil palm waste, which has previously been practically unavailable. Furthermore, the broken and compressed material 1 contained in the wood material preferably comprises 70% or more by mass of broken and compressed material 1 with dimensions of 8 mm to 25 mm in width, 10 mm to 50 mm in length, and 8 mm to 25 mm in thickness. This allows for the easy production of fiberboards using the same process using wood chips as conventional methods, even when used in combination with wood materials of traditional tree species.

[0045] Steaming is performed by treating the wood material containing the broken and compressed material 1 with high-temperature, high-pressure saturated steam. The steaming conditions are not particularly limited, but may be, for example, at a temperature of 150 to 200°C, a pressure of 0.5 to 2.0 MPa, and a time of 1 to 15 minutes.

[0046] Defibration is a process for breaking down the wood material containing the broken and compressed material 1 into wood fibers (mainly vascular tissue of palm plants). Defibration is performed by processing the wood material after steaming using a refiner or the like.

[0047] In this embodiment, drying may be performed after defibration. Drying is a process for reducing the moisture content of the defibrated wood fibers. Drying can be performed by heating the defibrated wood fibers. There are no particular restrictions on the moisture content of the dried wood fibers, but it is preferable that the moisture content be 20 mass % or less of the total amount of bone-dried wood fibers, for example.

[0048] The adhesive added to the dried wood fibers hardens and acts as a binder to bond the fibers together. The adhesive used is a synthetic resin adhesive that is liquid at room temperature and hardens when heated, such as an adhesive containing diphenylmethane diisocyanate or urea-melamine.

[0049] The wood fibers to which the adhesive has been added are formed into a desired shape, for example, into a mat.

[0050] The wood fibers to which the adhesive has been added are formed and then thermo-compressed. That is, the wood fibers formed into a plate or the like are then thermo-compressed. The thermo-compression molding can be performed, for example, by pressing the wood fibers between a pair of hot plates. The thermo-compression molding conditions are not particularly limited, but the molding temperature is, for example, in the range of 140°C to 230°C. The molding time is, for example, in the range of 10 seconds to 3 minutes. The molding pressure is, for example, in the range of 0.5 MPa to 4 MPa. The thermo-compression molding hardens the adhesive added to the wood fibers, bonding the wood fibers together, thereby producing the fiber board of this embodiment. The fiber board can be widely used, for example, in building materials, furniture, and residential interiors.

[0051] The process equipment for steaming, defibrating, adding adhesive, forming, hot-press molding, etc. can be the same as that used for conventionally manufacturing medium-density fiberboards. This increases the utilization efficiency of the equipment, and fiberboards can be obtained with excellent productivity even when using palm plant waste, which has poor storage properties and a low bulk density after drying, as raw materials.

[0052] (3) Variations The first embodiment is merely one of various embodiments of the present disclosure, and various modifications can be made to the first embodiment depending on the design and the like, as long as the object of the present disclosure can be achieved.

[0053] In the above, the case where the mat 3 is compressed by the pair of rolls 61 has been described, but this is not limiting, and the mat 3 may also be compressed by a flat press plate.

[0054] The above describes the case where grooves 40 are formed using a pair of rolls 61, but this is not limited to this. After forming a flat, plate-shaped compressed material 4 using a pair of rolls 61, grooves 40 may be formed using a device other than the pair of rolls 61.

[0055] In the above, the grooves 40 are formed on both surfaces of the plate-shaped compressed product 4, but this is not limiting, and the grooves 40 may be formed on only one surface. Also, if the plate-shaped compressed product 4 can be broken even without the grooves 40, the grooves 40 do not need to be formed.

[0056] In the above, the grooves 40 are formed in both the length and width directions of the plate-shaped compressed material 4, but this is not limited to this, and they may be formed in only one of the length and width directions of the plate-shaped compressed material 4.

[0057] (Embodiment 2) The method for manufacturing a fiber board according to this embodiment differs from that of embodiment 1 in the configuration of the broken and compressed product 1. Hereinafter, the same configurations as those of embodiment 1 will be assigned common reference numerals and explanations thereof will be omitted as appropriate. The configuration described in embodiment 2 can be applied in appropriate combination with the configuration described in embodiment 1 (including modified examples).

[0058] As shown in FIG. 4, in this embodiment, a sheet layer 5 is integrated with a plate-shaped compressed product 4. The sheet layer 5 contains a functional material. The functional material is at least one selected from pest repellents such as anti-mite agents, antibacterial agents, antiviral agents, fragrances, and colorants. The sheet layer 5 can be formed by laminating a sheet on the surface of the plate-shaped compressed product 4. The sheet can be a sheet (film) made by mixing a functional material with a fusible material such as a hot-melt resin or an easily decomposable material such as starch. Alternatively, a sheet (film) made by adhering a functional material to thin paper (mainly cellulose) can be used.

[0059] When the mat 3 is compressed to form the plate-shaped compressed product 4, the sheet layer 5 containing the meltable material is laminated together with the crushed material 2 of a palm plant and integrated with the plate-shaped compressed product 4. The sheet layer 5 melts when heated, allowing the functional material to impregnate between the fibers of the crushed material 2 contained in the plate-shaped compressed product 4. In the case of the sheet layer 5 containing a material that is easily decomposable, when the plate-shaped compressed product 4 is folded and divided, the sheet layer 5 is also folded and divided, and part of the sheet layer 5 adheres to the surface of the folded compressed product 1. When the wood material containing the folded compressed product 1 is steamed and defibrated, the sheet layer 5 decomposes or dissolves, leaving behind a mixture of the fibers of the crushed material 2 and the functional material.

[0060] (summary) As explained above, the first aspect is a method for producing a fiberboard in which a wood material is steamed and defibrated to obtain wood fibers, an adhesive is added to the resulting wood fibers, and the resulting fibers are then formed and thermo-compressed. The wood material includes a broken and compressed product (1). The broken and compressed product (1) is obtained by crushing a palm plant into chips with anisotropy in length, stacking these chips (2) to form a mat (3), compressing the mat (3) in the thickness direction to form a plate-like compressed product (4), and folding and dividing the plate-like compressed product (4).

[0061] According to the first aspect, when producing the broken compressed product (1), the plate-shaped compressed product (4) is broken rather than cut, so the fibers of the palm family plants contained in the pulverized product (2) are less likely to become short and are less likely to break. This allows for an increase in the amount of relatively long fibers in the broken compressed product (1), improving the strength of the resulting fiber board. Furthermore, because the plate-shaped compressed product (4) can be stored and transported in its pre-breaking state, the bulk density during storage and transport is high, improving storability and transportability.

[0062] The second embodiment is the method for producing a fiber board according to the first embodiment, in which the plate-shaped compressed product (4) has a dividing groove (40) on the surface.

[0063] According to the second aspect, the plate-shaped compressed material (4) can be folded and divided along the dividing groove (40) to obtain the folded compressed material (1), and the folded compressed material (1) can be easily formed from the plate-shaped compressed material (4).

[0064] A third aspect is the method for producing a fiber board according to the first or second aspect, wherein the moisture content of the plate-shaped compressed material (4) and the broken compressed material (1) is 25% by mass or less.

[0065] According to the third aspect, spoilage does not easily progress during storage, and storage properties are further improved.

[0066] A fourth aspect is the method for producing a fiber board according to any one of the first to third aspects, wherein the specific gravity of the broken and compressed product (1) is 0.35 or more and 1.50 or less.

[0067] According to the fourth aspect, the mechanical durability of the broken and compressed material (1) is less likely to decrease, the fibrous tissue constituting the crushed material (2) of the palm family plant is less likely to be damaged by compression, and the strength characteristics of the fiber board are less likely to decrease.

[0068] The fifth aspect is a method for manufacturing a fiberboard according to any one of the first to fourth aspects, in which the wood material contains 70% or more by mass of broken and compressed material (1) having a width of 8 mm to 25 mm, a length of 10 mm to 50 mm, and a thickness of 8 mm to 25 mm, based on the total amount of broken and compressed material (1) contained in the wood material.

[0069] According to the fifth aspect, wood fibers can be obtained under substantially the same conditions as conventional fiber boards, and can be used in combination with wood chips of conventional tree species.

[0070] The sixth aspect is a method for producing a fiber board according to any one of the first to fifth aspects, in which a sheet layer (5) containing a functional material is integrated with the plate-shaped compressed product (4) or the folded compressed product (1).

[0071] According to the sixth aspect, a functional cut and compressed product (1) can be obtained.

[0072] A seventh aspect is a method for producing a fiber board according to any one of the first to sixth aspects, wherein the crushed material (2) of the palm family plant contains crushed material (2) having a length of 0.8 mm or more and 50.0 mm or less and a diameter of 0.10 mm or more and 2.00 mm or less in a mass ratio of 70% or more of the total amount.

[0073] According to the seventh aspect, fiber boards of more stable quality can be easily produced. [Example]

[0074] Example 1 As shown in Table 1, the trunk part (OPT) of oil palm was extracted as the raw material for fiberboard and fed into a chipper to obtain 30-40 mm square (chip-like) palm plant pulverized material. The material was then removed using a foreign material remover, fed into a wet grinder, and ground. It was then dried to the specified moisture content using a rotary kiln. The material was then sieved through an 8.6-mesh sieve and then a 200-mesh sieve to reduce the proportion of palm plant parenchyma tissue, yielding palm plant pulverized material with an average length of 26.3 mm and an average diameter of 1.15 mm. This pulverized material contained 85% by mass of pulverized material with a length of 1.0 mm to 50.0 mm and a diameter of 0.10 mm to 2.00 mm (hereinafter referred to as "large-sized pulverized material"). The average length and diameter of the palm pulverized material were obtained by measuring the length and diameter of a predetermined amount of pulverized material with a magnifying glass and calculating the arithmetic mean. The mass ratio of large-size pulverized material was obtained by measuring the length and diameter of a predetermined amount of pulverized material with a magnifying glass, classifying the pulverized material according to whether it had a length of 0.8 mm or more and 50.0 mm or less and a diameter of 0.10 mm or more and 2.00 mm or less, and calculating the mass ratio of the pulverized material falling within this range to that not falling within this range.

[0075] Next, using a compressor such as that shown in Figure 1, a mat was formed using the resulting palm plant pulverized material as a raw material, and the mat was further compressed in the thickness direction to obtain a plate-shaped compressed material with a thickness of 15 mm, a specific gravity of 0.61, and a moisture content of 9% by mass, as shown in Figure 2.

[0076] Next, the plate-like compressed product was folded along the grooves and cut into pieces, to obtain folded compressed products measuring 15 mm x 40 mm x 15 mm.

[0077] Next, multiple broken and compressed pieces were placed in a pressure refiner, steamed at 170°C for 5 minutes, defibrated, and dried in a jet dryer at 200°C to create dried fiber (wood fiber).

[0078] After applying a 5% dispersion of diphenylmethane diisocyanate (MDI) as a binder to the dried fiber, it was molded at 180°C for 90 seconds to produce a thickness of 3 mm and a density of 800 kg / m 3 A fiber board (biomass fiber board) was obtained.

[0079] Example 2 Oil palm bunches (EFB) were used as the raw material for the fiber board, and a palm plant pulverization product with an average length of 31.1 mm, an average diameter of 1.32 mm, and a large-sized pulverization content of 82 mass% was produced using the same process as in Example 1.

[0080] Next, a plate-shaped compressed product with a thickness of 15 mm, a specific gravity of 0.62, and a moisture content of 10% by mass was prepared using the same process as in Example 1, and this plate-shaped compressed product was folded along the grooves to obtain a folded compressed product measuring 20 mm x 50 mm x 15 mm.

[0081] Thereafter, a fiber board was obtained in the same manner as in Example 1.

[0082] Example 3 Oil palm leaf fragments (OPF) were used as the raw material for the fiber board, and a palm plant crushed material with an average length of 28.5 mm, an average diameter of 1.20 mm, and a large-sized crushed material content of 80 mass% was produced using the same process as in Example 1.

[0083] Next, a plate-shaped compressed product with a thickness of 30 mm, a specific gravity of 0.60, and a moisture content of 10% by mass was prepared using the same process as in Example 1, and this plate-shaped compressed product was folded along the grooves to obtain a folded compressed product measuring 25 mm x 30 mm x 30 mm.

[0084] Thereafter, a fiber board was obtained in the same manner as in Example 1.

[0085] (Comparative Example) Oil palm trunk part (OPT) was used as the raw material for the fiber board, and a palm plant crushed material with an average length of 21.4 mm, an average diameter of 1.08 mm, and a large-sized crushed material content of 83 mass% was produced using the same process as in Example 1.

[0086] Next, the palm plant pulverization material obtained by the same process as in Example 1 was used as the raw material and compressed using a pelletizer into cylindrical pellets with a diameter of 15 mm and a length of 40 mm, yielding a compressed pellet-shaped material with a specific gravity of 0.61 and a moisture content of 9% by mass.

[0087] Thereafter, a fiber board was obtained in the same manner as in Example 1.

[0088] <Evaluation method> Mechanical durability evaluation The mechanical durability (DU) of the broken and compressed material and the pellet-shaped compressed material was measured based on the wood pellet quality standards of the Japan Wood Pellet Association.

[0089] DU = (m1 / m0) x 100 (%) m0: Mass before test m1: Mass after test (judgement) A: 97.5% or more C: Less than 97.5% Storage evaluation The bulk density of the compressed plate-like product and the compressed pellet-like product was measured to evaluate the storage properties. (judgement) A: Bulk density is 0.8 or more, and storage is easy. B: Bulk density is 0.3 or more and less than 0.8, and storage is normal. C: Bulk density is less than 0.3, and storage is poor. Strength evaluation A bending test was conducted based on "JIS A 5905 Fiberboard" to measure the bending strength of the fiberboard.

[0090] (judgement) A:25MPa or more B: Less than 25MPa, 20MPa or more C: Less than 20 MPa The results of each evaluation are shown in Table 2.

[0091] [Table 1]

[0092] [Table 2] [Explanation of symbols]

[0093] 1 Folded compressed material 2. Crushed palm plants 3. Matt 4. Plate-shaped compressed material 40 grooves 5 sheet layers

Claims

1. A method for producing a fiberboard in which wood materials are steamed and defibrated to obtain wood fibers, an adhesive is added to the wood fibers, and the resulting fibers are then formed and thermo-compressed. The wood material includes a broken and compressed material, The broken and compressed product is obtained by crushing a palm plant into chips having anisotropy in length, stacking the crushed chips to form a mat, compressing the mat in the thickness direction to form a plate-like compressed product having grooves for dividing on the surface, and folding and dividing the plate-like compressed product. How fiberboard is manufactured.

2. A method for manufacturing a fiberboard, which comprises steaming and defibrating wood material to obtain wood fibers, adding an adhesive to the wood fibers, and then forming and thermo-compressing the wood fibers, The wood material includes a broken and compressed material, The broken and compressed product is obtained by crushing a palm plant into chips having anisotropy in length, stacking the crushed chips to form a mat, compressing the mat in the thickness direction without using an adhesive to form a plate-like compressed product, and folding and dividing the plate-like compressed product. How fiberboard is manufactured.

3. The moisture content of the plate-shaped compressed product and the broken compressed product is 25% by mass or less, respectively. A method for producing the fiber board according to claim 1 or 2.

4. The specific gravity of the broken and compressed product is 0.35 or more and 1.50 or less. A method for producing the fiber board according to claim 1 or 2.

5. The wood material contains 70% or more by mass of broken and compressed pieces having a width of 8 mm to 25 mm, a length of 10 mm to 50 mm, and a thickness of 8 mm to 25 mm, based on the total amount of the broken and compressed pieces contained in the wood material. A method for producing the fiber board according to claim 1 or 2.

6. A sheet layer containing a functional material is integrated into the plate-shaped compressed product or the folded compressed product. A method for producing the fiber board according to claim 1 or 2.

7. The palm plant pulverized material contains 70% or more by mass of pulverized material having a length of 0.8 mm or more and 50.0 mm or less and a diameter of 0.10 mm or more and 2.00 mm or less, relative to the total amount. A method for producing the fiber board according to claim 1 or 2.

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