Method for producing fiberboard and compression material for producing fiberboard

Abstract

The object of the present disclosure is to provide a method of producing a fiberboard having improved strength, regardless of whether a compression material is produced using a flat die forming machine or a ring die forming machine. The method of producing a fiberboard according to the present disclosure includes a compression step, a cooking and fiber separation step, a forming step, and a hot-pressing step. The compression step includes compressing a mixture of a ground product of a palm plant and a wax to obtain a compression material (1). The cooking and fiber separation step includes cooking and fiber separation of the compression material (1) to obtain a wood fiber. The forming step includes adding a binder to the wood fiber, and then forming the wood fiber to obtain a mat-shaped formed product. The hot-pressing step includes pressing the mat-shaped formed product while heating the mat-shaped formed product.

Description

Technical Field

[0001] This disclosure generally relates to methods for producing fiberboard and compressed materials for producing fiberboard, and more specifically to a method for producing fiberboard from palm trees and compressed materials for producing fiberboard. Background Technology

[0002] Patent document 1 discloses a pelletizer for grinding and compressing biomass materials to produce pellets. The pelletizer includes a box, a die, and a pushing-in roller.

[0003] Here, the container has an internal space, an inlet located at the top of the container through which biomass material is fed into the container, and an outlet located at the bottom of the container through which the produced pellets are discharged. Furthermore, the mold is configured to divide the internal space into upper and lower sections and has a group of holes comprising a large number of vertical through-holes extending in a predetermined direction. Additionally, a push-in roller is positioned above the mold and rolls over the group of holes to grind and compress the biomass material passing through the inlet between the push-in roller and the mold, while simultaneously pushing the biomass material through each through-hole to produce pellets.

[0004] However, the pelletizer in Patent Document 1 has the following problem: the wood fibers included in the biomass material are prone to breakage and cutting during pellet production. The pelletizer in Patent Document 1 is an example of a so-called flat die forming machine, but so-called ring die forming machines also have this problem. Therefore, the resulting pellets often contain relatively short wood fibers. Consequently, when attempting to produce fiberboard from such pellets, it is difficult to increase the strength of the fiberboard because of the relatively short length of the wood fibers.

[0005] Reference List Patent documents Patent Document 1: JP 2018-144341 A Summary of the Invention

[0006] The purpose of this disclosure is to provide a method for producing fiberboard with increased strength, regardless of whether the compressed material is produced using a flat die forming machine or a ring die forming machine, and the compressed material used for producing fiberboard.

[0007] According to one aspect of this disclosure, a method for producing fiberboard includes: a compression step: compressing a mixture of ground palm fiber and wax to obtain a compressed material; a cooking and fiber separation step: cooking and separating the compressed material to obtain wood fibers; a forming step: adding an adhesive to the wood fibers and then forming the wood fibers to obtain a mat-shaped product; and a hot pressing step: pressing the mat-shaped product while heating it.

[0008] According to one aspect of this disclosure, a compressed material for producing fiberboard is a compressed material obtained by compressing a mixture of ground palm products and wax. Attached Figure Description

[0009] Figure 1 This is a partially transparent schematic perspective view of the compressed material (compressed material) used in the production of fiberboard according to this embodiment; and Figure 2 This is a schematic perspective view of the forming machine used in the method for producing fiberboard according to this embodiment. Detailed Implementation

[0010] 1. Overview As described above, the pelletizer of Patent Document 1 has the following problems: the wood fibers contained in the biomass material are prone to breakage, the wood fibers are cut, or the wood fibers crack during pellet production. The inventors believe this problem is caused by the following reasons: The biomass material coarsely ground and fed into the pelletizer typically has a shape that extends along the fiber direction. Therefore, the biomass material fed into the pelletizer of Patent Document 1 is often positioned on a die, causing the biomass material to extend in the transverse direction, and the wood fibers included in the biomass material are also often positioned on the die, causing the wood fibers to extend in the transverse direction. Therefore, when the direction of the perforation group with numerous through holes is inconsistent with the fiber direction of the wood fibers, the biomass material is pushed into the through holes, thus the wood fibers are prone to breakage. Furthermore, the direction of the perforation group's extension and the direction of the push-in roller rolling on the perforation group are perpendicular to each other, making it difficult for the biomass material to enter the through holes, and applying a force to the biomass material in a direction different from the fiber direction, thereby increasing the likelihood of wood fiber breakage. The inventors' considerations are as described above.

[0011] The inventors have conducted in-depth research on improving the strength of fiberboard by designing materials for it, rather than by improving the pelletizer itself. As a result, the inventors have developed a method for producing fiberboard. Specifically, the method for producing fiberboard according to this embodiment includes a compression step, a cooking and fiber separation step, a forming step, and a hot-pressing step.

[0012] The compression step includes using, for example... Figure 2 The molding machine 3 shown compresses a mixture of ground palm plant material and wax. Figure 2(Not shown in the image) to obtain compressed material 1. As described above, the ground product of the palm plant includes wax added thereto, which causes the wood fibers 2 included in the ground product to slide smoothly relative to each other, and the wood fibers 2 slide smoothly on the surface of the molding machine 3. This reduces the possibility of wood fiber 2 breakage, regardless of whether the compressed material 1 is produced by a flat die or a ring die molding machine 3. Therefore, many relatively long wood fibers 2 and / or many virtually crack-free wood fibers 2 are retained in the compressed material 1.

[0013] The cooking and fiber separation steps following the compression step include cooking and fiber separation of the compressed material 1 to obtain wood fibers 2. The forming step following the cooking and fiber separation step includes adding an adhesive to the wood fibers 2 and then shaping the wood fibers 2 to obtain a cushion-shaped molded product. The hot-pressing step following the forming step includes pressing the cushion-shaped molded product while heating it. Thus, a fiberboard is obtained.

[0014] There may be a situation where the length of the wood fibers 2 is reduced to some extent through the cooking and fiber separation steps, the forming step, and the hot pressing step. However, since many of the relatively long wood fibers 2 are retained in the compressed material 1 used to produce the fiberboard, the relatively long wood fibers 2 are included in the fiberboard even after these steps, compared to the case where no wax is added.

[0015] Therefore, the strength of the fiberboard can be increased.

[0016] 2. Detailed Explanation Examples of fiberboard according to this embodiment include insulation boards, medium-density fiberboard (MDF), and hardboard. Medium-density fiberboard is preferred.

[0017] The method for producing fiberboard includes a compression step, a cooking and fiber separation step, a forming step, and a hot pressing step. These steps will be described in turn below.

[0018] <Compression Steps> The compression step includes compressing a mixture of ground palm plant material and wax to obtain compressed material 1 (hereinafter also referred to as "compressed material 1") for the production of fiberboard. The ground palm plant material, wax, molding machine 3 and compressed material 1 will be described in sequence below.

[0019] <<Grinded products of palm trees>> Types of palm trees include, for example but not particularly limited to, oil palm, doub chusan palm, coconut palm, date palm, sago palm, açaí palm, and chusan palm. Usable parts of palm trees include, for example but not particularly limited to, the trunk, leaves, fruit, hollow fruit clusters, and seeds.

[0020] Oil palm is a palm tree grown in countries such as Malaysia, Indonesia, Thailand, and Colombia to produce edible oil, among other things. Oil palm trunks (OPT) are not strong enough as building materials and are therefore disposed of as unused resources. Furthermore, oil palm trunks contain sugar and are easily decomposed, so they are currently left to rot. However, the decomposition of oil palm trunks produces greenhouse gases, raising environmental concerns.

[0021] The shredded product of palm trees is obtained as a collection of wood chips obtained by shredding palm trees using a shredder. Each wood chip obtained by shredding palm trees generally has a shape that is elongated along the fiber direction. Each wood chip preferably has a length greater than or equal to 0.6 mm and less than or equal to 50.0 mm, and an outer diameter greater than or equal to 0.10 mm and less than or equal to 2.00 mm. Wood chips falling within these length and outer diameter ranges are referred to hereinafter as "preferred wood chips," and wood chips not falling within these length and outer diameter ranges are referred to hereinafter as "non-preferred wood chips." Note that the length and outer diameter of the wood chips included in the shredded product of palm trees can be determined by measuring the length and outer diameter of the wood chips, for example, by capturing an image of a predetermined amount of shredded palm tree products, or by observing using a magnifying eye.

[0022] Here, when the length of the wood chips is greater than or equal to 0.6 mm, the reduction in the strength of the fiberboard can be suppressed. Similarly, when the outer diameter of the wood chips is greater than or equal to 0.10 mm, the reduction in the strength of the fiberboard can be suppressed.

[0023] Furthermore, when the length of the wood chips is less than or equal to 50.0 mm, the reduction in surface smoothness of the fiberboard can be suppressed. Similarly, when the outer diameter of the wood chips is less than or equal to 2.00 mm, the reduction in surface smoothness of the fiberboard can be suppressed.

[0024] The preferred wood chip content, relative to the total amount of ground palm plant products (the total amount of preferred and non-preferred wood chips), is preferably greater than or equal to 70% by mass, more preferably greater than or equal to 80% by mass. A preferred wood chip content of greater than or equal to 70% by mass not only suppresses the reduction in fiberboard strength but also enables the production of fiberboard with more stable quality. Note that the upper limit of the preferred wood chip content, for example, but not particularly limited to, is less than or equal to 100% by mass.

[0025] Here, the parenchyma of palm trees can alter the quality of the fiberboard. Therefore, the ground palm product is preferably obtained by grinding the palm tree and then grading it to reduce the amount of parenchyma. That is, the ground palm product before grading includes: a ground product containing parenchyma as a main component; and a ground product containing vascular tissue as a main component. However, grading preferably reduces the amount of ground product containing a relatively small amount of parenchyma as a main component. Therefore, in the ground product after grading, the amount of ground product containing parenchyma as a main component is less than that in the ground product before grading. This increases the proportion of vascular tissue included in the compressed material 1, thereby enabling stable production of fiberboard. Note that parenchyma is tissue comprising parenchyma cells. Parenchyma includes, for example, assimilating tissue, secretory tissue, and storage tissue, and has physiological activities such as synthesis, decomposition, and storage.

[0026] One method for reducing the amount of undesirable wood chips (thin-walled and large-sized wood chips) by grading is, for example, but not particularly limited to, using two sieves with different mesh sizes. That is, the amount of undesirable wood chips is more easily reduced by passing the ground product through a sieve with a large mesh size but not through a sieve with a small mesh size. Examples of sieves with large mesh sizes include sieves with mesh sizes from 4.7 mesh (mesh size: 4.00 mm) to 16 mesh (mesh size: 1.00 mm). Conversely, examples of sieves with small mesh sizes include sieves with mesh sizes from 149 mesh (mesh size: 100 μm) to 235 mesh (mesh size: 63 μm).

[0027] Preferably, the ground product of palm trees is dried. The water content of the ground palm tree product is preferably less than or equal to 25% by mass, more preferably less than or equal to 20% by mass. A water content of less than or equal to 25% by mass in the ground palm tree product improves the shape retention of the compressed material 1. Furthermore, a water content of less than or equal to 25% by mass in the compressed material 1 can inhibit the decay of the lignocellulose 2 included in the compressed material 1, thus improving the storage characteristics of the compressed material 1. Note that the water content of the ground palm tree product can be determined by drying.

[0028] As mentioned above, this embodiment can use palm trees as plants for fiberboard production, thus making efficient use of resources.

[0029] Wax During the compression step, the wax causes the wood fibers 2 included in the ground palm product to slide smoothly relative to each other, and the wood fibers 2 slide smoothly on the surface of the molding machine 3. That is, the wax can inhibit the bending of the wood fibers 2. In addition, the wax can impart water resistance to the compressed material 1.

[0030] Examples of waxes include, but are not specifically limited to, natural and synthetic waxes. Waxes can be in liquid (e.g., emulsion) or solid form at room temperature. When the wax is in liquid form, at least some of the wax penetrates the wood fiber 2, and the synergistic effect of water and wax can soften the wood fiber 2 and reduce the likelihood of breakage. Conversely, when the wax is in solid form, for example, when using… Figure 2 In the case of the molding machine 3 shown, wax (not shown) is easily placed between the first surface 41 of the mold 4 and the wood fiber 2 (not shown) and between the pressure roller 5 and the wood fiber 2, so the cushioning effect can reduce the possibility of wood fiber 2 breaking.

[0031] Examples of natural waxes include, but are not limited to, paraffin wax, beeswax and carnauba wax.

[0032] Examples of synthetic waxes include, but are not limited to, polyethylene waxes and ethylene vinyl acetate waxes.

[0033] Relative to 100% by mass of the total mass (absolute dry mass) of the ground palm plant material, the proportion of wax added (excluding the total mass) is preferably greater than 0.05% by mass and less than or equal to 5% by mass, more preferably greater than or equal to 0.1% by mass and less than or equal to 1% by mass. When the proportion of wax added is greater than 0.05% by mass, the likelihood of bending of the wood fibers 2 is further reduced, and the water resistance of the compressed material 1 is further improved. When the proportion of wax added is less than or equal to 5% by mass, the reduction in the shape retention of the compressed material 1 can be suppressed.

[0034] Molding Machine For example, to obtain compressed material 1 from a mixture of ground palm plant material and wax, a forming machine 3 (granulator) can be used. Examples of forming machines 3 include, but are not particularly limited to, flat die forming machines and ring die forming machines. Note that while tableting can be used to obtain compressed material 1, granulation offers higher production efficiency than tableting.

[0035] Figure 2 An example of a forming machine 3 (flat die forming machine) is shown. The forming machine 3 includes a die 4 and at least one or more (two in this embodiment) pressure rollers 5. The forming machine 3 may also include a cutter (not shown).

[0036] The mold 4 has an annular shape. The mold 4 has a first surface 41, a second surface 42, and at least one or more (in this embodiment, multiple) through holes 40.

[0037] The first surface 41 is the surface on which a mixture of ground palm plant material and wax is fed.

[0038] The second surface 42 is the surface opposite to the first surface 41. The second surface 42 is the surface from which the compressed material 1 is extruded. As described above, the compressed material 1 is obtained at the second surface 42.

[0039] Each through-hole 40 extends from the first surface 41 to the second surface 42. Each through-hole 40 is a cylindrical space extending from the first surface 41 to the second surface 42. Each through-hole 40 is a space into which a mixture of ground palm fiber and wax is pushed to be compressed, thereby shaping the compressed material 1. Therefore, the inner diameter of each through-hole 40 is substantially equal to the outer diameter of the compressed material 1.

[0040] The pressure roller 5 rolls on the first surface 41 of the mold 4. This pushes the ground palm plant material and wax fed to the first surface 41 into the through hole 40. There is no particular limitation on the pressure at this time, but for example, it is greater than or equal to 0.5 MPa and less than or equal to 1.0 MPa.

[0041] Here, the rolling direction of the pressure roller 5 (parallel to the first surface 41) is different from the through-hole 40. In this embodiment, the rolling direction of the pressure roller 5 is perpendicular to the through-hole 40.

[0042] The pressure roller 5 includes a first pressure roller 51 and a second pressure roller 52. The first pressure roller 51 and the second pressure roller 52 are cylindrical with the same dimensions. The first pressure roller 51 and the second pressure roller 52 are rotatably connected to the two ends of a connecting shaft 53. The connecting shaft 53 is a shaft extending along a rotation axis C2. The first pressure roller 51 and the second pressure roller 52 can rotate in opposite directions about the rotation axis C2 (see...). Figure 2 (See the arrow in the diagram). At the center of connecting shaft 53, main shaft 50 is vertically fixed to connecting shaft 53. Main shaft 50 is a shaft extending along the rotation axis C1. Main shaft 50 can rotate about the rotation axis C1 (see...). Figure 2 (The arrow in the image). As described above, the rotation of the spindle 50 causes the pressure rollers 5 (first pressure roller 51 and second pressure roller 52) to roll on the first surface 41 of the mold 4.

[0043] Note that, although in Figure 2 Not shown, but the cutter is a component used to cut the compressed material 1 extruded from the second surface 42 into easily handleable lengths of a few centimeters.

[0044] <<Compressed Materials>> like Figure 1 As shown, the compressed material 1 has, for example, a granular shape. Specifically, the compressed material 1 is a cylindrical shape elongated in one direction. This one direction is the through-hole 40's direction of penetration. The action of wax in the compression step makes the wood fibers 2 less likely to break; therefore, many relatively long wood fibers 2 and / or many virtually crack-free wood fibers 2 are retained in the resulting compressed material 1. Furthermore, the compressed material 1 contains wax ( Figure 1 (not shown in the figure), thus improving the water resistance of the compression material 1.

[0045] The specific gravity of the compression material 1 is preferably greater than or equal to 0.35 and less than or equal to 1.50, more preferably greater than or equal to 0.40 and less than or equal to 1.50. Therefore, the mechanical durability of the compression material 1 is improved, and the compression material 1 is less likely to crack or break during transportation.

[0046] The water content of the compressed material 1 is preferably less than or equal to 25% by mass, more preferably less than or equal to 20% by mass. A water content of less than or equal to 25% by mass in the compressed material 1 improves the shape retention of the compressed material 1. In addition, a water content of less than or equal to 25% by mass in the compressed material 1 can inhibit the decay progress of the wood fibers 2 included in the compressed material 1, thus improving the storage characteristics of the compressed material 1. Note that the water content of the compressed material 1 can be determined by drying.

[0047] <Cooking and Fiber Separation Steps> The cooking and fiber separation step is the process of fiberizing the compressed material 1. Specifically, the cooking and fiber separation step involves cooking and separating the compressed material 1 to obtain lignocellulose 2. Specifically, saturated steam is introduced into the compressed material 1 to soften the lignin and decompose the compressed material 1 to obtain fibers or fiber bundles, thereby obtaining lignocellulose 2. In the cooking and fiber separation step, a known cooking and fiber separation apparatus can be used.

[0048] Here, there are no particular restrictions on the temperature during cooking, for example, above or equal to 150°C and below or equal to 200°C. There are no particular restrictions on the relative humidity during cooking, for example, above or equal to 90% RH. There are no particular restrictions on the time period of cooking and fiber separation steps, for example, longer than or equal to 1 minute and shorter than or equal to 15 minutes.

[0049] <Forming Steps> The forming step includes adding an adhesive to the wood fibers 2 and then shaping the wood fibers 2 to obtain a cushion-shaped molded product. Forming is preferably performed by a drying method. In dry forming, a known gravity forming machine or vacuum forming machine can be used. Note that, in addition to the adhesive, a water-repellent agent may also be added.

[0050] Here, there are no particular limitations on the adhesives, examples of which include diphenylmethane diisocyanate (MDI), urea resins, urea-melamine cocondensate resins, and phenolic resins.

[0051] There is no particular limitation on the amount of adhesive added relative to the total mass of wood fiber 2 and adhesive, for example, greater than or equal to 1% by mass and less than or equal to 10% by mass.

[0052] <Hot pressing steps> The hot pressing step includes pressing the pad-shaped molded product while heating it. A known hot press can be used in the hot pressing step. Spacers (thickness gauges) can be connected between the heating plates of the hot press. The spacers help to ensure uniform thickness of the fiberboard.

[0053] There are no particular restrictions on the heating temperature, for example, above or equal to 140°C and below or equal to 230°C. There are no particular restrictions on the pressing pressure, for example, above or equal to 0.5 MPa and less than or equal to 10 MPa. There are no particular restrictions on the hot pressing time, for example, longer than or equal to 10 seconds and shorter than or equal to 3 minutes.

[0054] Therefore, a fiberboard according to this embodiment is obtained. The thickness of the fiberboard is not particularly limited, for example, greater than or equal to 1 mm and less than or equal to 20 mm.

[0055] <Other> The method for producing fiberboard may also include a humidity conditioning step. This humidity conditioning step includes leaving the fiberboard exposed to the atmosphere for a period of time after the hot-pressing step, or treating the fiberboard in a humidity controller after the hot-pressing step. Since the moisture content of the fiberboard is very low after the hot-pressing step, it is preferable to increase the humidity in the fiberboard to a level close to the equilibrium operating conditions.

[0056] <Operation and Advantages> As described above, the method for producing fiberboard according to this embodiment includes a compression step, a cooking and fiber separation step, a forming step, and a hot pressing step.

[0057] The compression step involves compressing a mixture of ground palm fiber and wax to obtain compressed material 1. As described above, the ground palm fiber includes wax added thereto, which causes the wood fibers 2 included in the ground product to slide smoothly relative to each other, and the wood fibers 2 slide smoothly on the surface of the forming machine 3. Therefore, even when the rolling direction of the pressure roller 5 and the through-hole 40 in the forming machine 3 are not the same, the possibility of wood fiber 2 breaking is reduced. That is, the possibility of wood fiber 2 breaking is reduced regardless of whether the compressed material 1 is produced by a flat die or a ring die forming machine 3. Therefore, many relatively long wood fibers 2 and / or many nearly crack-free wood fibers 2 are retained in the compressed material 1. In addition, wax is present in the compressed material 1. Wax imparts water resistance (hydrophobic properties) to the compressed material 1. Therefore, even when water splashes onto the compressed material 1 during transportation or storage, the shape of the compressed material 1 is tended to be maintained.

[0058] The cooking and fiber separation step following the compression step includes cooking and fiber separation of the compressed material 1 to obtain wood fibers 2. The forming step following the cooking and fiber separation step includes adding an adhesive to the wood fibers 2 and then forming the wood fibers 2 to obtain a cushion-shaped molded product. The hot-pressing step following the forming step includes pressing the cushion-shaped molded product while heating it. Thus, a fiberboard is obtained.

[0059] There may be a situation where the length of the wood fibers 2 is reduced to some extent through the cooking and fiber separation steps, the forming step, and the hot pressing step. However, since many of the relatively long wood fibers 2 are retained in the compressed material 1 used to produce the fiberboard, the relatively long wood fibers 2 are still included in the fiberboard even after these steps, compared to the case where no wax is added.

[0060] Therefore, the strength of the fiberboard can be increased.

[0061] 3. Aspects As can be seen from the above embodiments, this disclosure includes the following aspects. In the following description, the reference numerals in parentheses are used only to clearly show the correspondence with the embodiments.

[0062] The first aspect is a method for producing fiberboard, the method comprising a compression step, a cooking and fiber separation step, a forming step, and a hot pressing step. The compression step comprises compressing a mixture of ground palm fiber and wax to obtain a compressed material (1). The cooking and fiber separation step comprises cooking and separating the compressed material (1) to obtain wood fibers (2). The forming step comprises adding an adhesive to the wood fibers (2) and shaping the wood fibers (2) to obtain a cushion-shaped product. The hot pressing step comprises pressing the cushion-shaped product while heating it.

[0063] According to this, the ground products of palm trees include wax added thereto, so the likelihood of wood fiber (2) breaking is reduced regardless of whether the compressed material (1) is produced using a flat die forming machine or a ring die forming machine, and many relatively long wood fibers (2) are retained, thereby improving the strength of the fiberboard.

[0064] The second aspect is a method for producing fiberboard based on the first aspect. In the second aspect, the milled product is obtained by the following steps: milling palm plants; and then grading them to reduce the amount of parenchyma.

[0065] Based on this, the possibility of thin-walled structures in the compressed material (1) is reduced, thus allowing for stable production of fiberboard.

[0066] The third aspect is a method for producing fiberboard based on the first or second aspect. In the third aspect, the pulverized product comprises wood chips, each wood chip having a length greater than or equal to 0.6 mm and less than or equal to 50.0 mm, an outer diameter greater than or equal to 0.10 mm and less than or equal to 2.00 mm, and the wood chip content being greater than or equal to 70% by mass relative to the total mass of the pulverized product.

[0067] This aspect can suppress the reduction in the strength of the fiberboard and suppress the reduction in the surface smoothness of the fiberboard.

[0068] The fourth aspect is a method for producing fiberboard based on any one of the first to third aspects. In the fourth aspect, a compressed material (1) is obtained using a forming machine (3) through the following steps, the forming machine (3) comprising: a die (4) having a first surface (41), a second surface (42) opposite to the first surface (41), and a through hole (40) extending from the first surface (41) to the second surface (42); and a pressure roller (5) configured to roll on the first surface (41): feeding a mixture to the first surface (41), pushing the mixture into the through hole (40) and compressing the mixture by the pressure roller (5) to form the compressed material (1), and extruding the compressed material (1) from the second surface (42).

[0069] According to this aspect, the ground product of palm trees includes wax added thereto, thus reducing the likelihood of wood fibers (2) breaking during the production of compressed material (1) even when the through-hole (40) and the rolling direction of the pressure roller (5) are not the same (e.g., perpendicular to each other).

[0070] The fifth aspect is a compressed material (1) for the production of fiberboard, which is a compressed material obtained by compressing a mixture of ground palm products and wax.

[0071] Based on this, many relatively long wood fibers (2) are retained, thus improving the strength of the fiberboard. In addition, the wax imparts water resistance (hydrophobic properties) to the compressed material (1), so that the shape of the compressed material (1) is easily maintained even when water is splashed on it during transportation and storage.

[0072] Example The present disclosure will now be described in detail with reference to the embodiments. Note that the present disclosure is not limited to the following embodiments.

[0073] 1. Sample As shown in Table 1 below, for each of Examples 1 to 7 and Comparative Examples, a compressed material for producing fiberboard was obtained, and then fiberboard was produced from the compressed material. Note that the "Average Length of Wood Chips" in Table 1 is the average length of wood chips included in the ground product of palm trees. Furthermore, the "Average Diameter of Wood Chips" in Table 1 is the average outer diameter of wood chips included in the ground product of palm trees.

[0074] Examples 1 to 7 and comparative examples will be described in detail below.

[0075] (1) Example 1 As raw material for fiberboard (palm family), oil palm trunks (OPT) are used and fed into a shredder to obtain cubic wood chips with a diameter greater than or equal to 30 mm and less than or equal to 40 mm. Foreign matter is removed from the cubic wood chips using a foreign matter remover. The cubic wood chips are then fed into a wet mill and ground to obtain the desired product. The product is further dried using a rotary kiln until the moisture content reaches a predetermined level, thus obtaining a dried, ground product.

[0076] The dried, ground product was then passed through an 8.6-mesh sieve (mesh size: 2.00 mm) and a 200-mesh sieve (mesh size: 75 μm). From the dried, ground product, a portion passing through the 8.6-mesh sieve but not the 200-mesh sieve was obtained. This ground product exhibited a reduced amount of thin-walled structure. The average length of the wood chips, the average diameter of the wood chips, and the preferred content of wood chips in the ground product are shown in Table 1. Note that the average length and average diameter of the wood chips were determined by measuring the length and outer diameter of the wood chips included in a predetermined amount of the ground product using a magnifying eyepiece; and obtaining their arithmetic mean. Furthermore, the preferred wood chip content is determined by the following steps: measuring the length and outer diameter of the wood chips included in a predetermined amount of the ground product using a magnifying eyepiece; grading the wood chips according to whether the length falls within the range of greater than or equal to 0.6 mm and less than or equal to 50.0 mm and whether the outer diameter falls within the range of greater than or equal to 0.10 mm and less than or equal to 2.00 mm; and obtaining the mass ratio of wood chips included in the above range (preferred wood chips) to wood chips not included in the above range (non-preferred wood chips).

[0077] Then, an emulsion-type polyvinyl wax (manufactured by BYK-Chemie Japan KK, product number "AQUACER531", melting point 130°C) was added as a wax to the milled product and mixed with it to obtain a mixture. The wax addition ratios are shown in Table 1.

[0078] Then, a granulator (flat die forming machine) is used to obtain cylindrical compressed material (granules) with an outer diameter of 8 mm and a length of 30 mm from the mixture. The specific gravity and water content of the compressed material are shown in Table 1.

[0079] The compressed material is then placed in a pressure refining mill and cooked at 170°C for 5 minutes, followed by fiber separation and drying at 200°C using a spray dryer to obtain wood fibers. Diphenylmethane diisocyanate (MDI) is added to the wood fibers as a binder, and the fibers are then shaped at 180°C for 90 seconds to obtain fibers with a thickness of 3 mm and a density of 800 kg / m³. 3 Fiberboard. Note that the amount of adhesive added is 5% by weight.

[0080] (2) Example 2 The ground product was obtained in a manner similar to that of Example 1, except that the mesh size of the two sieves was changed. The average length of the wood chips, the average diameter of the wood chips, and the preferred content of wood chips in the ground product are shown in Table 1.

[0081] Then, a compressible material was obtained in a manner similar to that of Example 1, except that the wax addition ratio was changed. The specific gravity and water content of the compressible material are shown in Table 1.

[0082] Then, fiberboard was produced from the compressed material in a manner similar to that of Example 1. Note that the thickness and density of the fiberboard in Example 2 are equal to those of the fiberboard in Example 1.

[0083] (3) Example 3 The ground product was obtained in a manner similar to that of Example 1, except that the mesh size of the two sieves was changed. The average length of the wood chips, the average diameter of the wood chips, and the preferred content of wood chips in the ground product are shown in Table 1.

[0084] Then, a compression material was obtained in a manner similar to that of Example 1, except that an emulsion-type paraffin-based wax (manufactured by BYK-Chemie Japan KK, product number "AQUACER 498", melting point 60°C) was used as the wax. The specific gravity and water content of the compression material are shown in Table 1.

[0085] Then, fiberboard was produced from the compressed material in a manner similar to that of Example 1. Note that the thickness and density of the fiberboard in Example 3 are equal to those of the fiberboard in Example 1.

[0086] (4) Example 4 The ground product was obtained in a manner similar to that of Example 1, except that coconut tree trunks (palm family) were used as the raw material for the fiberboard, and the mesh size of the two sieves was changed. The average length of the wood chips, the average diameter of the wood chips, and the preferred content of wood chips in the ground product are shown in Table 1.

[0087] Then, the compressed material was obtained in a manner similar to that of Example 1. The specific gravity and water content of the compressed material are shown in Table 1.

[0088] Then, fiberboard was produced from the compressed material in a manner similar to that of Example 1. Note that the thickness and density of the fiberboard in Example 4 are equal to those of the fiberboard in Example 1.

[0089] (5) Example 5 The ground product was obtained in a manner similar to that of Example 1, except that the mesh size of the two sieves was changed. The average length of the wood chips, the average diameter of the wood chips, and the preferred content of wood chips in the ground product are shown in Table 1.

[0090] Then, the compressed material was obtained in a manner similar to that of Example 1. The specific gravity and water content of the compressed material are shown in Table 1.

[0091] Then, fiberboard was produced from the compressed material in a manner similar to that of Example 1. Note that the thickness and density of the fiberboard in Example 5 are equal to those of the fiberboard in Example 1.

[0092] (6) Example 6 The ground product was obtained in a manner similar to that of Example 1, except that the mesh size of the two sieves was changed. The average length of the wood chips, the average diameter of the wood chips, and the preferred content of wood chips in the ground product are shown in Table 1.

[0093] Then, the compressed material was obtained in a manner similar to that of Example 1. The specific gravity and water content of the compressed material are shown in Table 1.

[0094] Then, fiberboard was produced from the compressed material in a manner similar to that of Example 1. Note that the thickness and density of the fiberboard in Example 6 are equal to those of the fiberboard in Example 1.

[0095] (7) Example 7 The ground product was obtained in a manner similar to that of Example 1, except that the mesh size of the two sieves was changed. The average length of the wood chips, the average diameter of the wood chips, and the preferred content of wood chips in the ground product are shown in Table 1.

[0096] Then, a compressible material was obtained in a manner similar to that of Example 1, except that the wax addition ratio was changed. The specific gravity and water content of the compressible material are shown in Table 1.

[0097] Then, fiberboard was produced from the compressed material in a manner similar to that of Example 1. Note that the thickness and density of the fiberboard in Example 7 are equal to those of the fiberboard in Example 1.

[0098] (8) Comparative Examples The ground product was obtained in a manner similar to that of Example 5. The average length of the wood chips, the average diameter of the wood chips, and the preferred content of wood chips in the ground product are shown in Table 1.

[0099] Then, a compressed material was obtained in a manner similar to that of Example 5, except that no wax was added. The specific gravity and water content of the compressed material are shown in Table 1.

[0100] Then, fiberboard was produced from the compressed material in a manner similar to that of Example 5. Note that the thickness and density of the fiberboard in the comparative example are equal to those of the fiberboard in Example 1.

[0101] 2. Testing (1) Water resistance Immerse the compressed material in water at 25°C. Maintain the compressed material at a water depth of 3 cm. After immersion for 10 seconds, remove the compressed material from the water and observe its swelling state (shape). Grade the observation results based on the following evaluation criteria to assess water resistance.

[0102] <Evaluation Criteria> A: No swelling was observed (shape retention).

[0103] B: Slight swelling was observed (partial deformation of shape).

[0104] C: Greater swelling (shape deformation) was observed than in case B.

[0105] (2) Strength The flexural strength of fiberboard was measured according to JIS A 5905 Fiberboards. The measured values ​​were graded based on the following evaluation criteria to assess the strength.

[0106] <Evaluation Criteria> A: Bending strength greater than or equal to 25 MPa.

[0107] B: Bending strength greater than or equal to 20 MPa and less than 25 MPa.

[0108] C: Bending strength less than 20 MPa.

[0109] (3) Surface smoothness According to "JIS B 0601 Surface Roughness", the centerline average roughness Ra of the fiberboard is measured. The measured values ​​are graded based on the following evaluation criteria to assess surface smoothness.

[0110] <Evaluation Reference> A: Ra is less than or equal to 5 μm.

[0111] B: Ra is greater than 5 μm and less than or equal to 15 μm.

[0112] C: Ra is greater than 15 μm.

[0113] [Table 1]

[0114] The fiberboards in Examples 1 to 7 showed better strength than the comparative example, thus confirming the effectiveness of adding wax to the ground products of palm trees.

[0115] Furthermore, the surface smoothness of the fiberboard in Examples 1 to 5 and Example 7 was better than that in Example 6, thus confirming that the preferred wood chip content of 70% by mass or more is effective.

[0116] Furthermore, the water resistance of the compression materials in Examples 1 to 6 was better than that in Example 7, thus confirming that a wax addition ratio greater than 0.05% by mass is effective. Note that no wax was used in the comparative examples, thus confirming that the water resistance of the compression materials in the comparative examples was lower than that in Example 7.

[0117] List of reference numerals 1. Compressed materials used in the production of fiberboard (compressed materials) 2 Wood fibers 3 molding machine 4 molds 40 through hole 41 First Surface 42 Second Surface 5. Pressure rollers.

Claims

1. A method for producing fiberboard, the method comprising: Compression step: Compress the mixture of ground palm plant material and wax to obtain compressed material; Cooking and fiber separation steps: The compressed material is cooked and separated into fibers to obtain wood fibers; Forming step: Add adhesive to the wood fibers, and then form the wood fibers to obtain a mat-shaped molded product; as well as Hot pressing step: Pressing the cushion-shaped molded product while heating it. The compressed material is obtained by means of the following steps using a molding machine, the molding machine comprising: a mold having a first surface, a second surface opposite to the first surface, and a through hole extending from the first surface to the second surface; And a pressure roller configured to roll on the first surface: The mixture is fed into the first surface. The mixture is pushed into the through-hole by the pressure roller and compressed to form the compressed material. The compressed material is extruded from the second surface.

2. The method according to claim 1, wherein The ground product is obtained by the following steps: grinding the palm plant; and then grading it to reduce the amount of parenchyma.

3. The method according to claim 1, wherein The ground product comprises wood chips, each chip having a length greater than or equal to 0.6 mm and less than or equal to 50.0 mm, and an outer diameter greater than or equal to 0.10 mm and less than or equal to 2.00 mm. The wood chips contain 70% or more by mass relative to the total mass of the ground product.

4. Compressed material used in the production of fiberboard. The compressed material is a mixture of ground palm leaves and wax, which is then compressed. The compressed material is obtained using a molding machine through the following steps, the molding machine comprising: A mold having a first surface, a second surface opposite to the first surface, and a through hole extending from the first surface to the second surface; And a pressure roller configured to roll on the first surface: The mixture is fed into the first surface. The mixture is pushed into the through-hole by the pressure roller and compressed to form the compressed material. The compressed material is extruded from the second surface.

5. The compression material according to claim 4, wherein... The wax is added at a rate greater than or equal to 0.05% by mass and less than or equal to 5% by mass relative to 100% by mass of the total mass of the ground palm plant.

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