Method for manufacturing fiber board and biomass compressed material for manufacturing fiber board

Abstract

A method for manufacturing a fiber board is provided, the method enabling boards with a stable quality to be easily manufactured also when Palmae plants having a low bulk density are employed. An adhesive is added to woody fibers obtained by steaming and defibrating a woody material. Then, the woody fibers are formed and are subjected to thermocompression molding. The woody material includes a compressed material obtained by compressing and integrating together a plurality of dried ground products of a Palmae plant.

Description

Fiberboard manufacturing method and compressed biomass for fiberboard manufacturing

[0001] The present disclosure relates to a method for producing a fiber board and a compressed biomass product for producing the fiber board. More particularly, the present disclosure relates to a method for producing a fiber board using a wood material and a compressed biomass product for producing the fiber board.

[0002] Patent Document 1 describes a method for manufacturing a wood fiberboard. In this manufacturing method, wood chips are steamed and defibrated to obtain wood fibers, which are then dried, and an isocyanate adhesive is added to the wood fibers, which are then foamed and hot-pressed. Starches are added to the wood chips before or during the steaming process. Furthermore, tropical wood chips are used as the wood chips.

[0003] However, in recent years, tropical wood has tended to decrease on a global scale, and as a substitute, Patent Document 2 proposes a fiberboard made from wood fibers obtained from oil palm.

[0004] JP 2002-052514 A JP 2018-069670 A

[0005] However, when the manufacturing method described in Patent Document 1 is applied to palm plants, there is a problem in that productivity decreases because palm plants are a material with poor storage properties and low bulk density after drying.

[0006] The present disclosure aims to provide a fiber board manufacturing method and compressed biomass product for fiber board manufacturing that are highly productive even when using palm plants, which are materials with poor storage properties and low bulk density after drying.

[0007] In one embodiment of the present disclosure, a fiberboard is manufactured by steaming and defibrating a wood material to obtain wood fibers, adding an adhesive to the wood fibers, and then forming and thermo-compressing the wood material. The wood material includes a compressed material obtained by compressing and integrating dried crushed materials of multiple palm family plants.

[0008] A compressed biomass material for fiber board production according to one embodiment of the present disclosure is a compressed material obtained by integrating dried pulverized materials of multiple palm family plants.

[0009] (Embodiment) (1) Overview Hereinafter, the process leading to the fiber board manufacturing method and compressed biomass material for fiber board manufacturing according to this embodiment will be described.

[0010] The current global wood board market is worth over 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 traditionally used tropical woods such as lauan and softwoods such as cedar are exhaustible resources that take more than 30 years to grow, so there is a growing need for technology to utilize alternative materials.

[0011] There are various 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 surface finishes. As alternatives to these depleted resources, technologies for using low-quality wood such as small diameter trees and fast-growing planted trees with short felling periods have been developed and are currently in widespread use around the world, but 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] In particular, fiberboards can be manufactured using only fibrous materials, rather than wood chips of a certain shape, and so in the past, many efforts have been made to utilize 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 into practical use due to issues in terms of quality, manufacturing, and raw material procurement.

[0013] In this context, palm trees such as oil palm and coconut palm, which are widely distributed mainly in tropical regions, have attracted 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 fruit bunches (EFB: Empty Fiber Bulk) are being discarded. In Malaysia, a palm oil-producing country, more than 50 million tons of these waste products are discarded annually. Furthermore, leaving these wastes unattended releases more than 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 this 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, palm trees have a moisture content of around 70-300%, more than twice that of regular tropical wood, meaning that raw wood rots within one to two weeks, making storage extremely difficult.

[0015] Furthermore, the apparent specific gravity of a typical palm plant in its green state is around 0.60 to 0.80, but after drying, its specific gravity drops to around 0.35. Therefore, when transporting green lumber, the amount of material obtained is about half of the mass actually transported. Furthermore, when dried on-site, 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 fine particles called parenchyma cells with a diameter of less than 0.5 mm. When fiberboards are typically produced using palm plants as raw materials using conventional methods, these fine particles not only cause reduced productivity during board production, such as clogging of cutting tools, poor drying, and quality variations, but also pose the problem of not being able to ensure sufficient strength performance of the fiberboard because they do not contribute to the development of strength.

[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, even when using palm plant waste materials that have poor storage properties and low bulk density after drying as raw materials, it is possible to obtain fiberboards with high productivity. At the same time, it is possible to provide fiberboards that can be used as an alternative to fiberboards in the global market in the future, thereby stabilizing procurement and helping to solve social issues in Southeast Asia.

[0019] In other words, the fiberboard manufacturing method according to this embodiment involves steaming and defibrating a wood material to obtain wood fibers, adding an adhesive to the wood fibers, and then forming and thermo-compressing the wood material. The wood material includes a compressed material obtained by compressing and integrating dried pulverized materials of multiple palm family plants.

[0020] As described above, the fiber board manufacturing method according to this embodiment uses a compressed biomass product obtained by compressing and integrating the dried pulverized material of multiple palm family plants. Because the fiber board is manufactured using a compressed biomass product whose fiber structure is resistant to damage and decay, it is easy to efficiently obtain a practical fiber board with excellent strength, even when using palm family plants, which are waste materials with poor storage properties and low bulk density after drying, as raw materials.

[0021] (2) Details <Compressed Biomass for Fiberboard Production> The compressed biomass for fiberboard production according to this embodiment is a compressed product of dried pulverized material from multiple palm family plants. Specifically, palm cuttings and crushed pieces, which are pulverized material from palm family plants, are used as raw materials. These are dried and then compressed together to obtain a compressed biomass product composed of renewable biological resources (palm family plants). The compressed biomass for fiberboard production (hereinafter sometimes simply referred to as "compressed biomass") has improved transportability and productivity compared to non-compressed pulverized material from palm family plants. Furthermore, the use of dried pulverized material prevents decay, increasing the material yield and improving productivity.

[0022] The type of palm plant used for the compressed biomass is not particularly limited, but it can also be the oil palm, the bougainvillea palm, the date palm, the sago palm, the acai palm, the palm grove, etc. Furthermore, the parts that can be used are not particularly limited, but can be the trunk, leaves, fruit, bunches, seeds, etc.

[0023] Palm plants are crushed and dried, and then compressed. The order of crushing and drying may be arbitrary, or they may be carried out simultaneously. The method for crushing palm plants is not particularly limited, but may 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 prevents the progression of decay. After crushing the palm plants, washing them with water to reduce the ash content is preferable, as this reduces the occurrence of process problems caused by ash in the steaming process described below.

[0024] The ground material of a palm family plant is an aggregate of fibrous materials (including powdery materials) obtained by grinding the above-mentioned usable parts of a palm family plant. The ground material of a palm family plant preferably includes vascular tissue of a palm family plant. Vascular tissue of a palm family plant is tissue that transports water and nutrients necessary for the growth of a palm family plant, and includes xylem and phloem. Xylem is a transport pathway for water and nutrients absorbed from the roots, and has vessels and tracheids. Phloem is a transport pathway for nutrients created by the leaves, and has phloem tubes.

[0025] The pulverized material of the palm family preferably has a length of 0.8 mm to 50.0 mm and a diameter of 0.10 mm to 2.00 mm. If the length of the pulverized material is shorter than 0.8 mm or the diameter of the pulverized material is smaller than 0.10 mm, the vascular tissue of the palm family contained in the pulverized material according to this embodiment becomes too fine, which tends to reduce the strength of the fiber board. If the length of the pulverized material is longer than 50.0 mm or the diameter of the pulverized material is larger than 2.00 mm, the fiber shape of the wood fibers (described below) constituting the fiber board according to this embodiment becomes too coarse, which tends to reduce the surface smoothness of the fiber board. Note that "diameter" in this disclosure refers to the diameter.

[0026] The length of the pulverized palm material is more preferably within the range of 5.0 mm to 40.0 mm, and the diameter is more preferably within the range of 0.3 mm to 2.00 mm.

[0027] The length and diameter of the palm family crushed material can be obtained by photographing a predetermined amount of crushed material or observing it with a magnifying glass and measuring the length and diameter.

[0028] The crushed material having a length of 0.8 mm to 50.0 mm and a diameter of 0.10 mm to 2.00 mm preferably accounts for 70% or more by mass of the total amount of crushed palm plant material. If this mass ratio is less than 70%, the fiber components contributing to the strength development of the fiber board of this embodiment will be reduced, making the strength of the fiber board more likely to decrease. In addition, since the proportion of palm plant parenchyma tissue, the main component of the fine powder, is increased in the crushed palm plant material, blade clogging, poor drying, quality variations, etc. may occur more easily, making it difficult to produce fiber boards stably. The crushed palm plant having a length of 0.8 mm to 50.0 mm and a diameter of 0.10 mm to 2.00 mm more preferably accounts for 80% or more by mass of the total amount of crushed palm plant material, and most preferably 100%.

[0029] The pulverized palm plant material is preferably obtained by pulverizing a palm plant and then classifying it to reduce the amount of palm plant parenchyma tissue. In other words, the pulverized palm plant material preferably contains small pulverized material composed primarily of palm plant parenchyma tissue and large pulverized material composed primarily of palm plant vascular tissue, and is obtained by reducing the amount of these small pulverized material. Palm plant parenchyma tissue is tissue composed of palm plant parenchyma cells. Palm plant parenchyma tissue includes assimilation tissue, secretory tissue, storage tissue, etc., and has physiological functions such as synthesis, decomposition, and storage.

[0030] If palm plant parenchyma tissue is present in large amounts in a pulverized palm product, the palm plant parenchyma tissue is in the form of a fine powder, which can make it difficult to stably produce fiberboards. Therefore, in this embodiment, the amount of palm plant parenchyma tissue is reduced in order to obtain a pulverized palm product with a low content of palm plant parenchyma tissue. A method for reducing the amount of palm plant parenchyma tissue is to remove small pulverized material by classification. Possible classification methods include sieving, air sorting, and water bathing, but are not particularly limited thereto.

[0031] The compressed biomass product according to this embodiment is obtained by compressing and integrating multiple dried pulverized materials. That is, the compressed biomass product according to this embodiment includes dried pulverized materials of multiple palm family plants (biomass), and is a compressed product obtained by integrating these pulverized materials. The shape of the compressed biomass product may be, but is not limited to, a tablet, pellet, tablet, briquette, block, or plate. The compressed biomass product is compressed and integrated into a predetermined shape using a compression molding machine such as a pelletizer. The pulverized material is integrated by compression force without using an adhesive. However, an 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 with the pulverized material and integrated. In this case, these functions can be imparted to the resulting fiber board, which is preferable.

[0032] The specific gravity of the compressed biomass product is preferably in the range of 0.35 to 1.50. If the specific gravity of the compressed biomass product is less than 0.35, the mechanical durability of the compressed biomass product decreases, making it more likely to crumble or break during transportation. If the specific gravity of the compressed biomass product is greater than 1.50, the fibrous tissue constituting the pulverized palm plant material may be damaged by compression, making the strength characteristics of the final fiber board more likely to decrease. The specific gravity of the compressed biomass product is more preferably in the range of 0.40 to 1.50. If it is less than 0.40, the bulk density will be high, which will cause volumetric rate-limiting during transportation, increasing the number of round trips during transportation. For this reason, the specific gravity of the compressed biomass product is preferably in the range of 0.40 to 1.50.

[0033] The compressed biomass product preferably has a moisture content of 25% by mass or less, more preferably 20% by mass or less. If the moisture content is higher than 25% by mass, the compressed biomass product is likely to lose its shape retention and become more susceptible to spoilage, which also reduces its storage properties.

[0034] Thus, when the compressed biomass product of this embodiment has a specific gravity in the range of 0.35 to 1.50, storage properties and mechanical durability are improved, and the fibrous tissue of the palm family plant is less susceptible to compression damage. Furthermore, when the moisture content of the compressed biomass product of this embodiment is 25% by mass or less, it is less susceptible to decay and has improved storage properties. Note that "mechanical durability" in this disclosure refers to shape retention, and refers to the property of being less likely to crumble or break during storage.

[0035] <Method for manufacturing fiberboard> In the method for manufacturing a fiberboard according to this embodiment, a wood material is steamed and defibrated to obtain wood fibers, to which an adhesive is added, followed by forming and thermo-compression molding. The compressed biomass material according to this embodiment is then used as the wood material. By using the compressed biomass material, the method for manufacturing a fiberboard according to this embodiment can easily produce boards of consistent quality, even when palm trees with low bulk densities are used. The compressed biomass material may be used alone as the wood material, or the compressed biomass material may be used in combination with crushed tropical wood or coniferous wood, which has traditionally been used in the manufacture of medium-density fiberboard.

[0036] Steaming involves treating woody materials (compressed biomass) with high-temperature, high-pressure saturated steam. The steaming conditions are not particularly limited, but may be, for example, a temperature of 150 to 200°C, a pressure of 0.5 to 2.0 MPa, and a time of 1 to 15 minutes. Steaming is carried out using a digester or the like.

[0037] Defibration is a process that breaks down woody materials (compressed biomass) into wood fibers (mainly vascular tissue of palm plants). Defibration involves processing woody materials after steaming using a refiner or similar.

[0038] After defibration, drying is performed as necessary. Drying is a process to reduce the moisture content of the defibrated wood fibers. Drying can be performed by supplying hot air to the defibrated wood fibers. The moisture content of the wood fibers after drying is not particularly limited, but it is preferable that it be 20 mass% or less based on the total amount of wood fibers after bone drying. Drying may be performed after adding adhesive to the wood fibers, before adding adhesive to the wood fibers, while adding adhesive to the wood fibers, or by adding adhesive to the wood fibers, drying, and then adding adhesive again.

[0039] The adhesive added to the wood fibers hardens and acts as a binder to bond the fibers together. The adhesive is a synthetic resin adhesive that is liquid at room temperature and hardens when heated, such as an adhesive containing diphenylmethane diisocyanate or an adhesive containing urea-melamine.

[0040] The wood fibers to which the adhesive has been added are formed into a desired shape, for example, into a mat.

[0041] 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, between 140°C and 230°C. The molding time is, for example, between 10 seconds and 3 minutes. The molding pressure is, for example, between 0.5 MPa and 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, for example, building materials, furniture, and residential interiors.

[0042] Furthermore, the process equipment for these steps, such as steaming, defibrating, adding adhesive, forming, and hot-press molding, can be the same as that used for conventional medium-density fiberboard production. This increases the utilization efficiency of the equipment, and fiberboards can be produced with excellent productivity even when using palm plant waste, which has poor storage properties and a low bulk density after drying, as raw materials.

[0043] Example 1 As shown in Table 1, trunk tissue (OPT) was extracted from oil palm trees as a raw material for fiberboards and placed in a chipper to obtain 30-40 mm square palm plant pulverized material. The material was then removed using a foreign matter remover, placed in a wet grinder, and ground. It was then dried to a predetermined moisture content using a rotary kiln. The material was then sieved through an 8.6-mesh sieve and then through a 200-mesh sieve to reduce the proportion of palm plant parenchyma tissue, yielding palm plant pulverized material with an average length of 21.4 mm and an average diameter of 1.08 mm. This pulverized material contained 83% by mass of pulverized material with a length of 0.8 mm to 50.0 mm and a diameter of 0.10 mm to 2.00 mm (hereinafter, pulverized material in this range will be referred to as "large-sized pulverized material"). The average length and average diameter of the palm pulverized material are obtained by measuring the length and diameter of a predetermined amount of pulverized material using a magnifying glass and calculating the arithmetic mean. The mass ratio of large-size pulverized material is obtained by measuring the length and diameter of a predetermined amount of pulverized material using a magnifying glass, classifying the pulverized material according to whether it has a length of 0.8 mm or more and a diameter of 0.10 mm or more and a diameter of 2.00 mm or less, and calculating the mass ratio of the pulverized material that does not fall within this range to that of the pulverized material that does not fall within this range.

[0044] The obtained palm plant pulverized material was used as a raw material and compressed into cylindrical pellets with a diameter of 15 mm and a length of 40 mm using a pelletizer, yielding a compressed biomass product with a specific gravity of 0.61 and a moisture content of 9% by mass.

[0045] These compressed biomass materials were placed in a pressure refiner, steamed at 170°C for 5 minutes, defibrated, and dried in a jet dryer at 200°C to produce dried fiber (wood fiber).

[0046] Diphenylmethane diisocyanate (MDI) was dispersed and applied as a binder to the dried fiber at a concentration of 5% by mass, and then molded at 180°C for 90 seconds to produce a sheet with a thickness of 3 mm and a density of 800 kg / m. ３ A fiber board of 10 ...

[0047] Example 2: Using oil palm bunches (EFB) as the raw material for a fiber board, a pulverized palm plant material with an average length of 32.5 mm, an average diameter of 0.30 mm, and a large-size pulverized material content of 92% by mass was produced using the same process as in Example 1. The pulverized palm plant material was then compressed using a tablet molding machine to produce tablets with a diameter of 10 mm and a thickness of 5 mm, resulting in a compressed biomass material with a specific gravity of 1.00 and a moisture content of 12% by mass. A fiber board was produced in the same manner as in Example 1, except for using this compressed biomass material.

[0048] Example 3: Using coconut trunks as the raw material for fiber boards, a pulverized palm plant material with an average length of 7.8 mm, an average diameter of 1.87 mm, and a large-size pulverized material content of 75% by mass was produced using the same process as in Example 1. The pulverized palm plant material was then compressed using a briquette to produce cylindrical briquettes with a diameter of 80 mm and a length of 150 mm, yielding a compressed biomass material with a specific gravity of 1.35 and a moisture content of 19% by mass. A fiber board was produced in the same manner as in Example 1, except for using this compressed biomass material.

[0049] Example 4: Oil palm trunk tissue (OPT) was used as the raw material for the fiber board, and a pulverized palm plant material with an average length of 40.6 mm, an average diameter of 0.30 mm, and a large-size pulverized material content of 92% by mass was produced using the same process as in Example 1. A triaxial compactor was then used to compress the pulverized palm plant material, producing a 100 mm square block-shaped compressed product, yielding a compressed biomass product with a specific gravity of 0.40 and a moisture content of 9% by mass. A fiber board was produced in the same manner as in Example 1, except for using this compressed biomass product.

[0050] Example 5: Using oil palm bunches (EFB) as the raw material for a fiber board, a pulverized palm plant material with an average length of 15.6 mm, an average diameter of 0.79 mm, and a large-size pulverized material content of 70% by mass was produced using the same process as in Example 1. The pulverized palm plant material was then compressed using a roller compactor to produce a plate-shaped compressed product with a width of 120 mm, a length of 200 mm, and a thickness of 5 mm, resulting in a compressed biomass product with a specific gravity of 1.22 and a moisture content of 15% by mass. A fiber board was produced in the same manner as in Example 1, except that this compressed biomass product was used.

[0051] Example 6 A fiber board was obtained in the same manner as in Example 1, except that the specific gravity of the compressed biomass pellets was set to 0.30. The content of large-sized pulverized material in the compressed biomass pellets was 83% by mass.

[0052] Example 7 A fiber board was obtained in the same manner as in Example 1, except that when a pellet-shaped compressed biomass product was prepared, the specific gravity of the compressed product was set to 1.55.

[0053] Example 8 A fiber board was obtained in the same manner as in Example 1, except that when preparing the pellet-shaped compressed biomass product, the moisture content of the compressed product was set to 27% by mass.

[0054] (Example 9) A fiber board was obtained in the same manner as in Example 4, except that when creating a block-shaped compressed biomass product, crushed material of a palm plant having an average length of 75.7 mm, an average diameter of 0.30 mm, and a large-size crushed material content of 65% by mass was used to create the compressed biomass product.

[0055] (Example 10) A fiber board was obtained in the same manner as in Example 2, except that when preparing the tablet-shaped compressed biomass product, crushed material of a palm family plant having an average length of 32.5 mm, an average diameter of 0.05 mm, and a large-size crushed material content of 63% by mass was used to prepare the compressed biomass product.

[0056] (Example 11) A fiber board was obtained in the same manner as in Example 3, except that when preparing the briquette-shaped compressed biomass product, crushed material of a palm plant having an average length of 10.3 mm, an average diameter of 1.92 mm, and a large-size crushed material content of 61% by mass was used to prepare the compressed biomass product.

[0057] (Example 12) A fiber board was obtained in the same manner as in Example 1, except that when preparing the block-shaped compressed biomass product, crushed material of a palm plant having an average length of 32.5 mm, an average diameter of 2.50 mm, and a large-size crushed material content of 65% by mass was used to prepare the compressed biomass product.

[0058] (Example 13) A fiber board was obtained in the same manner as in Example 1, except that when creating a block-shaped biomass compressed product, crushed material of a palm family plant having an average length of 0.81 mm, an average diameter of 0.15 mm, and a large-size crushed material content of 60% by mass was used to create the biomass compressed product.

[0059] <Evaluation Method> Mechanical Durability Evaluation The mechanical durability DU of the compressed biomass product after molding was measured based on the wood pellet quality standard of the Japan Wood Pellet Association. DU = (m1 / m0) x 100 (%) m0: Mass before test m1: Mass after test (Assessment) A: 97.5% or more B: 96.5% or more but less than 97.5% C: Less than 96.5%

[0060] - Evaluation of storage stability The mold resistance of the compressed biomass was measured based on "JIS Z 2911 mold resistance test method." (Judgment) A: 14 days or more B: 10 days or more but less than 14 days C: Less than 10 days

[0061] Strength evaluation: A bending test was conducted on the fiberboards based on "JIS A 5905 Fiberboard" to measure their bending strength. (Judgment) A: 25 MPa or more B: Less than 25 MPa, 20 MPa or more C: Less than 20 MPa Surface smoothness evaluation: The center line average roughness Ra of the fiberboards was measured in accordance with "JIS B 0601 Surface roughness". (Judgment) A: 5 μm or less B: More than 5 μm, 15 μm or less C: More than 15 μm The results of each evaluation are shown in Table 2.

[0062]

[0063]

[0064] All of the examples were rated A or B, confirming that there is no problem with the practicality of the fiber boat and the manufacturing method thereof.

[0065] In particular, a comparison between Example 1 and Example 6 confirmed that when the specific gravity of the compressed biomass product is low, the mechanical durability of the compressed biomass product is somewhat low and it becomes more susceptible to breakage during transportation or use.

[0066] By comparing Example 1 and Example 7, it was confirmed that when the specific gravity of the compressed biomass material is too high, the strength of the fiber board is likely to decrease.

[0067] By comparing Example 1 and Example 8, it was confirmed that if the moisture content of the compressed biomass product is too high, the storage properties of the compressed biomass product are likely to decrease.

[0068] By comparing Example 4 and Example 9, it was confirmed that when the average length of the pulverized material is large and the content of large-sized pulverized material is low, the surface smoothness of the fiber board is likely to decrease.

[0069] A comparison between Example 2 and Example 10 confirmed that when the average diameter of the pulverized material is small and the content of large-sized pulverized material is low, the strength of the fiber board is likely to decrease.

[0070] A comparison between Example 3 and Example 11 confirmed that when the content of large-sized pulverized material is low, the strength of the fiber board is likely to decrease.

[0071] According to Examples 9, 10, 12 and 13, it is preferable that the average length and average diameter of the pulverized material and the content of large-sized pulverized material are each within the above-mentioned specified ranges.

[0072] As described above, the fiberboard manufacturing method according to the first aspect involves steaming and defibrating a wood material to obtain wood fibers, adding an adhesive to the wood fibers, and then forming and thermo-compressing the wood material. The wood material includes a compressed material obtained by compressing and integrating dried pulverized materials of multiple palm family plants.

[0073] According to this aspect, even when palm trees with low bulk density are used, fiberboards of stable quality can be easily produced. This improves storage stability, which is an issue with palm trees, and also improves transportability.

[0074] A second aspect is the method for producing a fiber board according to the first aspect, wherein the compressed product has a specific gravity of 0.35 to 1.50 and a moisture content of 25% by mass or less.

[0075] According to this aspect, even when palm trees with low bulk density are used, fiberboards of stable quality can be easily produced. This improves storage stability, which is an issue with palm trees, and also improves transportability.

[0076] The third aspect is a method for manufacturing a fiber board according to the first or second aspect, in which the crushed palm plant is crushed and then classified to reduce the amount of palm plant parenchyma tissue.

[0077] According to this embodiment, the finely powdered parenchyma tissue of the palm family plant is less likely to be included in the wood material, which has the advantage of facilitating stable production of fiberboards.

[0078] A fourth aspect is a method for manufacturing a fiber board according to any one of the first to third aspects, wherein the crushed material of the palm family plant contains crushed 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 in a mass ratio of 70% or more.

[0079] This embodiment has the advantage that fiberboards of more stable quality can be easily produced.

[0080] The compressed biomass material for fiber board production according to the fifth embodiment is a compressed material obtained by integrating dried pulverized materials of a plurality of palm plants.

[0081] According to this aspect, by using the compressed biomass material in the production of fiberboard, fiberboards of stable quality can be easily produced even when palm plants with low bulk density are used. In addition, the storage properties, which are an issue with palm plants, can be improved, and at the same time, transportability can be improved.

[0082] A sixth aspect is the compressed biomass material for fiber board production according to the fifth aspect, which has a specific gravity of 0.35 to 1.50 and a moisture content of 25 mass % or less.

[0083] According to this aspect, by using the compressed biomass material in the production of fiberboard, fiberboards of stable quality can be easily produced even when palm plants with low bulk density are used. In addition, the storage properties, which are an issue with palm plants, can be improved, and at the same time, transportability can be improved.

[0084] A seventh aspect is a compressed biomass material for fiber board production according to the fifth or sixth aspect, wherein the crushed material of the palm family plant contains crushed 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 in a mass ratio of 70% or more.

[0085] This embodiment has the advantage that fiberboards of more stable quality can be easily produced.

Claims

1. In a method for manufacturing a fiber board, in which an adhesive is added to wood fibers obtained by steaming and defibrating wood materials, followed by forming and hot pressing, the wood material includes a compressed product obtained by compressing and integrating pulverized materials of a plurality of dried palm plants. A method for manufacturing a fiber board.

2. The method for manufacturing a fiber board according to claim 1, wherein the compressed product has a specific gravity of 0.35 or more and 1.50 or less and a moisture content of 25% by mass or less.

3. The method for manufacturing a fiber board according to claim 1 or 2, wherein the pulverized material of the palm plant is obtained by classifying the pulverized palm plant to reduce the soft cell tissue of the palm plant.

4. The method for manufacturing a fiber board according to any one of claims 1 to 3, wherein the 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 is contained in the pulverized material of the palm plant in a mass ratio of 70% or more.

5. A biomass compressed product for manufacturing a fiber board, which is a compressed product obtained by integrating pulverized materials of a plurality of dried palm plants.

6. The biomass compressed product for manufacturing a fiber board according to claim 5, having a specific gravity of 0.35 or more and 1.50 or less and a moisture content of 25% by mass or less.

7. The biomass compressed product for manufacturing a fiber board according to claim 5 or 6, wherein the 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 is contained in the pulverized material of the palm plant in a mass ratio of 70% or more.