Method for producing fiberboard and compressed material for production of fiberboard
Patent Information
- Authority / Receiving Office
- MY · MY
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-02-16
- Publication Date
- 2026-07-31
AI Technical Summary
Existing methods for manufacturing fiberboards using biomass pellets often result in short wood fibers due to breakage during the pelletization process, leading to reduced strength of the final product.
A method involving the compression of a mixture of crushed palm plant material and wax, followed by steaming and defibration to obtain longer wood fibers, which are then molded with an adhesive and hot-pressed to enhance the fiberboard's strength and water resistance.
This approach results in fiberboards with improved strength and water resistance, as the wax reduces fiber breakage during processing and maintains the length of wood fibers, enhancing the board's mechanical durability and surface smoothness.
Abstract
Description
Fiberboard manufacturing method and compressed material for fiberboard manufacturing
[0001] The present disclosure generally relates to a method for producing fiberboard and a compressed product for producing fiberboard, and more particularly to a method for producing fiberboard using palm plants and a compressed product for producing fiberboard.
[0002] Patent Document 1 discloses a pellet manufacturing apparatus that crushes and compresses biomass material into pellets. This pellet manufacturing apparatus includes a box, a die, and a pressing roller.
[0003] The box has an internal space, with an inlet at the top for feeding biomass material and an outlet at the bottom for discharging the produced pellets. The die is installed to divide the internal space into upper and lower sections, and has a group of holes consisting of numerous through holes that penetrate from top to bottom and extend in a predetermined direction. The push roller is arranged above the die and rolls over the group of holes, pulverizing the biomass material fed from the inlet between the die and the die, and forcing the material through each through hole and compressing it into pellets as it passes through the through holes.
[0004] However, the pellet manufacturing apparatus of Patent Document 1 has a problem in that the wood fibers contained in the biomass material are easily broken and cut during pellet production. While the pellet manufacturing apparatus of Patent Document 1 is an example of a so-called flat die type molding machine, the above problem also applies to so-called ring die type molding machines. As a result, many relatively short wood fibers tend to remain in the resulting pellets. Therefore, when attempting to manufacture a fiberboard using such pellets, it is difficult to improve the strength of the fiberboard due to the relatively short length of the wood fibers.
[0005] Japanese Patent Application Laid-Open No. 2018-144341
[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 regardless of whether the compressed product is manufactured using a flat die type or ring die type molding machine, and a compressed product for manufacturing a fiber board.
[0007] A method for manufacturing a fiber board according to one embodiment of the present disclosure includes a compression step in which a mixture of crushed palm plant material and wax is compressed to obtain a compressed material; a steaming and defibrating step in which the compressed material is steamed and defibrated to obtain wood fibers; a forming step in which an adhesive is added to the wood fibers and molded to obtain a mat-like molded product; and a hot-pressing step in which the mat-like molded product is heated and pressed.
[0008] A compressed material for producing a fiber board according to one embodiment of the present disclosure is a compressed material obtained by compressing a mixture of ground palm plant material and wax.
[0009] Fig. 1 is a schematic perspective view partially showing a compressed product for use in the fiber board manufacturing method according to the present embodiment. Fig. 2 is a schematic perspective view showing a molding machine used in the fiber board manufacturing method according to the present embodiment.
[0010] 1. Overview As described above, the pellet manufacturing apparatus of Patent Document 1 suffers from the problem of wood fibers contained in biomass material easily breaking during pellet production, resulting in breakage or cracking of the wood fibers. The inventors believe the cause of this problem is as follows: Because coarsely pulverized biomass material for feeding into the pellet manufacturing apparatus generally has an elongated shape with a long fiber direction, the biomass material fed into the pellet manufacturing apparatus of Patent Document 1 tends to be horizontally oriented on the die, and the wood fibers contained in the biomass material also tend to be horizontally oriented on the die. Therefore, the wood fibers are forced into the through holes with the extension direction of the numerous through holes misaligned with the fiber direction of the wood fibers, making the wood fibers prone to breaking. In addition, because the extension direction of the holes and the rolling direction of the push roller over the holes are perpendicular, the biomass material has difficulty entering the through holes, and a force in a direction opposite to the fiber direction is applied, making the wood fibers prone to breaking. The inventors believe this is the case.
[0011] The inventors of the present invention have conducted extensive research to improve the strength of fiber boards by devising innovative fiber board materials rather than improving the pellet manufacturing apparatus itself. As a result, they have developed the following fiber board manufacturing method. That is, the fiber board manufacturing method according to this embodiment includes a compression step, a steam-defibration step, a forming step, and a hot-pressing step.
[0012] In the compression step, for example, a molding machine 3 as shown in Figure 2 is used to compress a mixture of pulverized palm plant material and wax (not shown in Figure 2) to obtain a compressed product 1. In this way, the addition of wax to the pulverized palm plant material improves the sliding properties between the wood fibers 2 contained in the pulverized material and between the wood fibers 2 and the surface of the molding machine 3. Therefore, whether a flat die type or a ring die type molding machine 3 is used to produce the compressed product 1, the wood fibers 2 are less likely to break. Therefore, many relatively long wood fibers 2 and wood fibers 2 with few cracks remain in the compressed product 1.
[0013] In the steaming and defibrating process after the compression process, the compressed product 1 is steamed and defibrated to obtain wood fibers 2. In the forming process after the steaming and defibrating process, an adhesive is added to the wood fibers 2 and the wood fibers are molded to obtain a mat-like molded product. In the heat and pressure process after the forming process, the mat-like molded product is pressed while being heated, thereby obtaining a fiber board.
[0014] The length of the wood fibers 2 may be somewhat shortened through the steaming, defibrating, forming, and hot pressing processes. However, since many relatively long wood fibers 2 remain in the compressed product 1 used for manufacturing fiberboards, the fiberboards containing these processes will still contain relatively long wood fibers 2 compared to those containing no wax.
[0015] Therefore, the strength of the fiber board can be improved.
[0016] 2. Details The fiberboard according to this embodiment includes an insulation board, a medium density fiberboard (MDF), and a hardboard. Preferably, the fiberboard is a medium density fiberboard.
[0017] The method for producing a fiber board includes a compression step, a steam-defibration step, a forming step, and a hot-pressing step. These steps will be described in order below.
[0018] <Compression Step> In the compression step, the mixture of the pulverized palm plant material and wax is compressed to obtain a compressed material for fiber board production 1 (hereinafter sometimes simply referred to as "compressed material 1"). Below, the pulverized palm plant material, wax, molding machine 3, and compressed material 1 will be described in order.
[0019] <<Pulverized Palm Plants>> The types of palm plants are not particularly limited, but examples thereof include oil palm, borage palm, coconut palm, date palm, sago palm, acai, and palm trees. Usable parts of palm plants are not particularly limited, but examples thereof include the trunk, leaves, fruit, bunches, and seeds.
[0020] In particular, oil palm is a type of palm tree that has been planted in Malaysia, Indonesia, Thailand, Colombia, and other countries to obtain edible oil. Oil palm trunks (OPT) are treated as an unused resource because they lack the strength to be used as building materials. Furthermore, because oil palm trunks contain sugar and are prone to decay, they are currently left to rot and disposed of, but this poses environmental concerns because greenhouse gases are generated as they decay.
[0021] The crushed material of palm plants is obtained as a collection of chips by crushing palm plants using a chipper. The chips obtained by crushing palm plants generally have an elongated shape with a long length in the fiber direction. The chips preferably have a length of 0.6 mm to 50.0 mm and an outer diameter of 0.10 mm to 2.00 mm. Chips that meet these lengths and outer diameters may be referred to as "suitable chips" below, and chips that do not meet these lengths and outer diameters may be referred to as "unsuitable chips" below. The length and outer diameter of the chips contained in the crushed material of palm plants can be obtained by photographing a predetermined amount of crushed palm plants or observing them with a magnifying glass and measuring the length and outer diameter of the chips.
[0022] Here, by making the chip length 0.6 mm or more, it is possible to suppress a decrease in the strength of the fiber board, and this also applies when the chip outer diameter is 0.10 mm or more.
[0023] Furthermore, by setting the chip length to 50.0 mm or less, it is possible to prevent a decrease in the surface smoothness of the fiber board. This also applies when the chip outer diameter is 2.00 mm or less.
[0024] The content of suitable chips is preferably 70% by mass or more, more preferably 80% by mass or more, based on the total amount of palm plant pulverization (total amount of suitable chips and non-suitable chips). A suitable chip content of 70% by mass or more not only prevents a decrease in the strength of the fiber board, but also facilitates the production of fiber boards of more stable quality. The upper limit of the suitable chip content is not particularly limited, but is, for example, 100% by mass or less.
[0025] Here, parenchyma tissue of palm plants can be a factor in quality variations in fiberboards. Therefore, it is preferable that the pulverized material of palm plants be produced by pulverizing palm plants and then classifying them to reduce the amount of parenchyma tissue. That is, the pulverized material of palm plants before classification contains pulverized material primarily composed of parenchyma tissue and pulverized material primarily composed of vascular tissue. By classifying the pulverized material, it is preferable to reduce the amount of pulverized material primarily composed of relatively small parenchyma tissue. Thus, the pulverized material after classification contains a reduced amount of pulverized material primarily composed of parenchyma tissue compared to the pulverized material before classification. This increases the proportion of vascular tissue contained in the compressed material 1, enabling stable production of fiberboards. Note that parenchyma tissue is tissue composed of parenchyma cells. Parenchyma tissue includes assimilation tissue, secretory tissue, storage tissue, etc., and has physiological functions such as synthesis, decomposition, and storage.
[0026] The method for reducing the weight of non-suitable chips (parenchymal tissue and large chips) by classification is not particularly limited, but examples include using two sieves with different mesh sizes. That is, pulverized material that passes through a sieve with a large mesh size and does not pass through a sieve with a small mesh size is likely to be reduced in weight as non-suitable chips. Here, examples of sieves with large mesh sizes include sieves with 4.7 mesh (mesh size 4.00 mm) to 16 mesh (mesh size 1.00 mm). On the other hand, examples of sieves with small mesh sizes include sieves with 149 mesh (mesh size 100 μm) to 235 mesh (mesh size 63 μm).
[0027] The pulverized material of the palm family plant is preferably dried. The moisture content of the pulverized material of the palm family plant is preferably 25% by mass or less, more preferably 20% by mass or less. When the moisture content of the pulverized material of the palm family plant is 25% by mass or less, the shape retention of the compressed material 1 is improved. Furthermore, the progression of decay of the wood fibers 2 contained in the compressed material 1 can be prevented, improving the storage properties of the compressed material 1. The moisture content of the pulverized material of the palm family plant can be determined by the total drying method.
[0028] In this way, in this embodiment, palm plants can be used as plants for manufacturing fiber boards, thereby enabling effective use of resources.
[0029] <<Wax>> During the compression process, wax improves the sliding properties between the wood fibers 2 contained in the pulverized material of palm plants and between the wood fibers 2 and the surface of the molding machine 3. In other words, wax can prevent bending of the wood fibers 2. Furthermore, wax can also impart water resistance to the compressed product 1.
[0030] The wax is not particularly limited, but examples include natural waxes and synthetic waxes. The wax may be liquid (e.g., emulsion) or solid at room temperature. When the wax is liquid, at least a portion of the wax penetrates the wood fibers 2, and the synergistic effect with water makes the wood fibers 2 flexible and less likely to break. On the other hand, when the wax is solid, for example, when using the molding machine 3 shown in FIG. 2, the wax (not shown) is more likely to be interposed between the wood fibers 2 (not shown) and the first surface 41 of the die 4, and between the wood fibers 2 and the compression roller 5, thereby providing a cushioning effect that makes the wood fibers 2 less likely to break.
[0031] Examples of natural waxes include, but are not limited to, paraffin wax, beeswax, and carnauba wax.
[0032] The synthetic wax is not particularly limited, but examples thereof include polyethylene wax and ethylene vinyl acetate wax.
[0033] The wax content (external percentage) is preferably more than 0.05% by mass and not more than 5% by mass, more preferably 0.1% by mass or more and not more than 1% by mass, relative to 100% by mass of the total mass (bone dry mass) of the pulverized palm plant. A wax content of more than 0.05% by mass can further suppress bending of the wood fibers 2 and can further improve the water resistance of the compressed product 1. A wax content of 5% by mass or less can suppress a decrease in the shape retention of the compressed product 1.
[0034] <<Molding Machine>> To obtain the compressed product 1 from the mixture of the pulverized palm plant material and wax, for example, a molding machine 3 (pelletizer) can be used. The molding machine 3 is not particularly limited, but examples thereof include a flat die type molding machine and a ring die type molding machine. Note that a tableting method can also be used to obtain the compressed product 1, but the pelletizer method has the advantage of higher production efficiency than the tableting method.
[0035] 2 shows an example of a molding machine 3 (flat die type molding machine). The molding machine 3 includes a die 4 and at least one (two in this embodiment) compression roller 5. The molding machine 3 may further include a cutter (not shown).
[0036] The die 4 has an annular shape and includes a first surface 41, a second surface 42, and at least one through-hole 40 (in this embodiment, a plurality of through-holes 40).
[0037] The first surface 41 is the surface to which the mixture of crushed palm plant material and wax is supplied.
[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 product 1 is extruded. In this manner, the compressed product 1 is obtained from the second surface 42.
[0039] The through-hole 40 penetrates from the first surface 41 to the second surface 42. The through-hole 40 is a cylindrical space extending from the first surface 41 to the second surface 42. The through-hole 40 is the space into which the mixture of crushed palm plant material and wax is forced and compressed to form the compressed product 1. Therefore, the inner diameter of the through-hole 40 is approximately equal to the outer diameter of the compressed product 1.
[0040] The compression roller 5 rolls on the first surface 41 of the die 4. As a result, the crushed palm plant material and wax supplied to the first surface 41 are pressed into the through holes 40. The pressure at this time is not particularly limited, but is, for example, 0.5 MPa or more and 1.0 MPa or less.
[0041] Here, the rolling direction of the compression roller 5 (the direction parallel to the first surface 41) is not the same as the penetration direction of the through holes 40. In this embodiment, the rolling direction of the compression roller 5 is perpendicular to the penetration direction of the through holes 40.
[0042] The compression rollers 5 include a first compression roller 51 and a second compression roller 52. The first compression roller 51 and the second compression roller 52 are cylindrical and have the same dimensions. The first compression roller 51 and the second compression roller 52 are rotatably attached to both ends of a connecting shaft 53. The connecting shaft 53 is an axis extending along the rotation axis C2. The first compression roller 51 and the second compression roller 52 are rotatable in opposite directions around the rotation axis C2 (see the arrows in FIG. 2 ). A main shaft 50 is fixed at the center of the connecting shaft 53 and perpendicular to the connecting shaft 53. The main shaft 50 is an axis extending along the rotation axis C1. The main shaft 50 is rotatable around the rotation axis C1 (see the arrows in FIG. 2 ). As the main shaft 50 rotates in this manner, the compression rollers 5 (the first compression roller 51 and the second compression roller 52) roll on the first surface 41 of the die 4.
[0043] Although not shown in FIG. 2, the cutter is a member for cutting the compressed product 1 extruded from the second surface 42 into pieces having a length of several centimeters that are easy to handle.
[0044] <Compressed Product> As shown in Figure 1, the compressed product 1 is, for example, in the form of a pellet. Specifically, the compressed product 1 is cylindrical and extends in one direction. This one direction is derived from the direction in which the through-holes 40 penetrate. The wax used in the compression process makes the wood fibers 2 less likely to break, so that many relatively long wood fibers 2 and wood fibers 2 with few cracks remain in the resulting compressed product 1. Furthermore, the compressed product 1 contains wax (not shown in Figure 1), which improves the water resistance of the compressed product 1.
[0045] The specific gravity of the compressed product 1 is preferably 0.35 or more and 1.50 or less, more preferably 0.40 or more and 1.50 or less, so that the mechanical durability of the compressed product 1 is improved and the compressed product 1 is less likely to be crushed or broken during transportation.
[0046] The moisture content of the compressed product 1 is preferably 25% by mass or less, more preferably 20% by mass or less. A moisture content of 25% by mass or less of the compressed product 1 improves the shape retention of the compressed product 1. It also prevents the progression of decay of the wood fibers 2 contained in the compressed product 1, improving the storage properties of the compressed product 1. The moisture content of the compressed product 1 can be determined by the total drying method.
[0047] <Steaming and defibrating process> The steaming and defibrating process is a process for fiberizing the compressed material 1. That is, in the steaming and defibrating process, the compressed material 1 is steamed and defibrated to obtain wood fibers 2. Specifically, saturated steam is introduced into the compressed material 1 to soften the lignin in the compressed material 1, and the compressed material 1 is dissociated into fibers or fiber bundles to obtain wood fibers 2. In the steaming and defibrating process, a known steaming and defibrating device can be used.
[0048] The temperature during steaming is not particularly limited, but is, for example, 150° C. to 200° C. The relative humidity during steaming is not particularly limited, but is, for example, 90% RH or higher. The time for the steaming and defibrating step is not particularly limited, but is, for example, 1 minute to 15 minutes.
[0049] <Forming step> In the forming step, an adhesive is added to the wood fibers 2 and then the mixture is molded to obtain a mat-like molded product. Forming is preferably performed by a dry method. In dry forming, a known gravity former or suction former can be used. A water repellent may be added in addition to the adhesive.
[0050] The adhesive is not particularly limited, but examples thereof include diphenylmethane diisocyanate (MDI), urea resin, urea-melamine co-condensation resin, and phenol resin.
[0051] The amount of adhesive to be blended relative to the total mass of the wood fibers 2 and adhesive is not particularly limited, but is, for example, 1 mass % or more and 10 mass % or less.
[0052] <Hot Pressing Step> In the hot pressing step, the mat-shaped molded product is pressed while being heated. A known hot press can be used in the hot pressing step. A distance bar (thickness gauge) may be attached between the hot plates of the hot press. The distance bar can make the thickness of the fiber board uniform.
[0053] The heating temperature is not particularly limited, but is, for example, 140° C. to 230° C. The pressure during pressing is not particularly limited, but is, for example, 0.5 MPa to 10 MPa. The heat-pressing time is not particularly limited, but is, for example, 10 seconds to 3 minutes.
[0054] In this manner, the fiber board according to the present embodiment is obtained. The thickness of the fiber board is not particularly limited, but is, for example, 1 mm or more and 20 mm or less.
[0055] <Others> The fiber board manufacturing method may further include a humidity control step. In the humidity control step, the fiber board after the heat and pressure step is left in the air for a certain period of time or is treated in a humidity control device. Since the moisture content of the fiber board immediately after the heat and pressure step is very low, it is preferable to increase the humidity until the moisture content approaches the moisture content equilibrium under the usage conditions.
[0056] <Operation and Effect> As described above, the method for producing a fiber board according to this embodiment includes a compression step, a steam-defibration step, a forming step, and a heat-pressing step.
[0057] In the compression process, a mixture of pulverized palm plant material and wax is compressed to obtain the compressed product 1. The addition of wax to the pulverized palm plant material improves the sliding properties of the wood fibers 2 contained in the pulverized material relative to each other and between the wood fibers 2 and the surface of the molding machine 3. Therefore, even if the rolling direction of the compression rollers 5 and the penetration direction of the through holes 40 in the molding machine 3 are not the same, the wood fibers 2 are less likely to break. In other words, whether a flat die type or a ring die type molding machine 3 is used to produce the compressed product 1, the wood fibers 2 are less likely to break. Therefore, many relatively long wood fibers 2 and wood fibers 2 with fewer cracks remain in the compressed product 1. Furthermore, wax is present in the compressed product 1. This wax imparts water resistance (water repellency) to the compressed product 1. This allows the compressed product 1 to easily maintain its shape even if it is exposed to water during transportation and storage.
[0058] In the steaming and defibrating process after the compression process, the compressed product 1 is steamed and defibrated to obtain wood fibers 2. In the forming process after the steaming and defibrating process, an adhesive is added to the wood fibers 2 and the wood fibers are molded to obtain a mat-like molded product. In the heat and pressure process after the forming process, the mat-like molded product is pressed while being heated, thereby obtaining a fiber board.
[0059] The length of the wood fibers 2 may be somewhat shortened through the steaming, defibrating, forming, and hot pressing processes. However, since many relatively long wood fibers 2 remain in the compressed product 1 used for manufacturing fiberboards, the fiberboards containing these processes contain relatively long wood fibers 2 compared to those containing no wax.
[0060] Therefore, the strength of the fiber board can be improved.
[0061] 3. Aspects As is clear from the above embodiments, the present disclosure includes the following aspects. In the following, reference numerals are given in parentheses only to clarify the correspondence with the embodiments.
[0062] The first aspect is a method for producing a fiberboard, comprising a compression step, a steaming and defibrating step, a forming step, and a hot-pressing step. In the compression step, a mixture of pulverized palm plant material and wax is compressed to obtain a compressed product (1). In the steaming and defibrating step, the compressed product (1) is steamed and defibrated to obtain wood fibers (2). In the forming step, an adhesive is added to the wood fibers (2) and molded to obtain a mat-like molded product. In the hot-pressing step, the mat-like molded product is pressed while being heated.
[0063] According to this embodiment, by adding wax to the crushed material of the palm family plant, whether the compressed material (1) is produced using a molding machine of the flat die type or the ring die type, the wood fibers (2) are less likely to break, and a large number of relatively long wood fibers (2) remain, thereby improving the strength of the fiber board.
[0064] A second aspect is a method for producing a fiber board based on the first aspect. In the second aspect, the pulverized material is obtained by pulverizing the palm plant and then classifying it to reduce the amount of parenchyma tissue.
[0065] According to this embodiment, parenchymal tissue is less likely to be included in the compressed material (1), and a fiber board can be produced stably.
[0066] A third aspect is a method for producing a fiber board according to the first or second aspect, wherein the pulverized material contains chips having a length of 0.6 mm to 50.0 mm and an outer diameter of 0.10 mm to 2.00 mm in an amount of 70 mass% or more relative to the total mass of the pulverized material.
[0067] According to this aspect, it is possible to suppress a decrease in the strength of the fiber board, and also to suppress a decrease in the surface smoothness of the fiber board.
[0068] A fourth aspect is a method for producing a fiberboard based on any one of the first to third aspects. In the fourth aspect, a molding machine (3) is used, which includes a die (4) having a first surface (41), a second surface (42) opposite the first surface (41), and a through hole (40) penetrating from the first surface (41) to the second surface (42), and a compression roller (5) that rolls on the first surface (41). The mixture is supplied to the first surface (41), and the compression roller (5) compresses the mixture by forcing it into the through hole (40) to form the compressed product (1), and the compressed product (1) is obtained by extruding it from the second surface (42).
[0069] According to this embodiment, even if the penetration direction of the through holes (40) and the rolling direction of the compression roller (5) are not the same direction (for example, even if they are perpendicular), the addition of wax to the crushed palm plant makes the wood fibers (2) less likely to break when producing the compressed product (1).
[0070] The fifth aspect is a compressed material (1) for producing a fiberboard, which is a compressed material (1) obtained by compressing a mixture of ground palm plant and wax.
[0071] According to this embodiment, the strength of the fiberboard can be improved by leaving a large amount of relatively long wood fibers 2. Furthermore, the wax imparts water resistance (water repellency) to the compressed product 1, which makes it easier to maintain the shape of the compressed product 1 even if it is exposed to water during transportation or storage.
[0072] The present disclosure will be specifically described below using examples, but the present disclosure is not limited to the following examples.
[0073] 1. Samples As shown in Table 1 below, compressed materials for fiberboard production were obtained for Examples 1 to 7 and the Comparative Example, and then fiberboards were produced using these compressed materials. Note that the "average chip length" in Table 1 is the average length of chips contained in the crushed material of palm plants. Also, the "average chip diameter" in Table 1 is the average outer diameter of chips contained in the crushed material of palm plants.
[0074] Examples 1 to 7 and a comparative example will be described in detail below.
[0075] (1) Example 1 Oil palm trunk (OPT) was used as the raw material (palm plant) for the fiber board, and this was fed into a chipper to obtain granulated angular material of 30 mm to 40 mm. After removing foreign matter from the granulated angular material using a foreign matter remover, the material was fed into a wet grinder and pulverized, and further dried to a predetermined moisture content using a rotary kiln to obtain a dried granulated material.
[0076] Next, for the dried pulverized product, an 8.6 mesh (opening 2.00 mm) sieve and a 200 mesh (opening 75 μm) sieve were used. Then, from the dried pulverized product, a pulverized product that passed through the 8.6 mesh sieve but did not pass through the 200 mesh sieve was obtained. This pulverized product had reduced parenchymal tissue. The average chip length, average chip diameter, and suitable chip content of this pulverized product are as shown in Table 1. The average chip length and average chip diameter were obtained by measuring the length and outer diameter of the chips contained in each pulverized product using a magnifying glass for a predetermined amount of pulverized product and calculating the arithmetic mean. The suitable chip content was obtained by measuring the length and outer diameter of the chips contained in a predetermined amount of pulverized product using a magnifying glass, and classifying the chips according to whether the length was 0.6 mm or more and 50.0 mm or less and the outer diameter was 0.10 mm or more and 2.00 mm or less, and calculating the mass ratio of the chips contained in this range (suitable chips) to the chips not contained in this range (unsuitable chips).
[0077] Next, emulsion-type polyethylene wax (product number "AQUACER 531" manufactured by BIGG-Chemie Japan Co., Ltd., melting point 130°C) was added as a wax to the above pulverized material and mixed to obtain a mixture. The wax addition rate is shown in Table 1.
[0078] Next, the mixture was compressed into cylindrical pellets (pellets) with an outer diameter of 8 mm and a length of 30 mm using a pelletizer (flat die type molding machine). The specific gravity and moisture content of the compressed pellets are shown in Table 1.
[0079] The compressed material was then placed in a pressure refiner, steamed at 170°C for 5 minutes, defibrated, and dried in a jet dryer at 200°C to obtain wood fibers. Diphenylmethane diisocyanate (MDI) was added to the wood fibers as an adhesive, and the fibers were molded at 180°C for 90 seconds to produce a material with a thickness of 3 mm and a density of 800 kg / m. ３ The amount of adhesive used was 5% by mass.
[0080] (2) Example 2 A pulverized product was obtained in the same manner as in Example 1, except that the mesh size of the two sieves was changed. The average chip length, average chip diameter, and preferred chip content of this pulverized product are as shown in Table 1.
[0081] Next, except for changing the wax addition rate, a compressed product was obtained in the same manner as in Example 1. The specific gravity and moisture content of this compressed product are as shown in Table 1.
[0082] Then, the compressed product was used to produce a fiber board in the same manner as in Example 1. The thickness and density of the fiber board in Example 2 were the same as those of the fiber board in Example 1.
[0083] (3) Example 3 A pulverized product was obtained in the same manner as in Example 1, except that the mesh size of the two sieves was changed. The average chip length, average chip diameter, and preferred chip content of this pulverized product are as shown in Table 1.
[0084] Next, a compressed product was obtained in the same manner as in Example 1, except that an emulsion-type paraffin wax (manufactured by BIGG-Chemie Japan, product number "AQUACER 498", melting point 60°C) was used as the wax. The specific gravity and water content of this compressed product are as shown in Table 1.
[0085] The compressed product was then used to produce a fiber board in the same manner as in Example 1. The thickness and density of the fiber board in Example 3 were the same as those of the fiber board in Example 1.
[0086] (4) Example 4 A pulverized material was obtained in the same manner as in Example 1, except that coconut trunks were used as the raw material (palm family plant) for the fiber board and the mesh size of the two sieves was changed. The average chip length, average chip diameter, and preferred chip content of this pulverized material are as shown in Table 1.
[0087] Next, a compressed product was obtained in the same manner as in Example 1. The specific gravity and moisture content of this compressed product are shown in Table 1.
[0088] The compressed product was then used to produce a fiber board in the same manner as in Example 1. The thickness and density of the fiber board in Example 4 were the same as those of the fiber board in Example 1.
[0089] (5) Example 5 A pulverized product was obtained in the same manner as in Example 1, except that the mesh sizes of the two sieves were changed. The average chip length, average chip diameter, and preferred chip content of this pulverized product are as shown in Table 1.
[0090] Next, a compressed product was obtained in the same manner as in Example 1. The specific gravity and moisture content of this compressed product are shown in Table 1.
[0091] The compressed product was then used to produce a fiber board in the same manner as in Example 1. The thickness and density of the fiber board in Example 5 were the same as those of the fiber board in Example 1.
[0092] (6) Example 6 A pulverized product was obtained in the same manner as in Example 1, except that the mesh sizes of the two sieves were changed. The average chip length, average chip diameter, and preferred chip content of this pulverized product are as shown in Table 1.
[0093] Next, a compressed product was obtained in the same manner as in Example 1. The specific gravity and moisture content of this compressed product are shown in Table 1.
[0094] Then, the compressed product was used to produce a fiber board in the same manner as in Example 1. The thickness and density of the fiber board of Example 6 were the same as those of the fiber board of Example 1.
[0095] (7) Example 7 A pulverized product was obtained in the same manner as in Example 1, except that the mesh size of the two sieves was changed. The average chip length, average chip diameter, and preferred chip content of this pulverized product are as shown in Table 1.
[0096] Next, except for changing the wax addition rate, a compressed product was obtained in the same manner as in Example 1. The specific gravity and moisture content of this compressed product are as shown in Table 1.
[0097] Then, the compressed product was used to produce a fiber board in the same manner as in Example 1. The thickness and density of the fiber board of Example 7 were the same as those of the fiber board of Example 1.
[0098] (8) Comparative Example A pulverized product was obtained in the same manner as in Example 5. The average chip length, average chip diameter, and preferred chip content of this pulverized product are as shown in Table 1.
[0099] Next, a compressed product was obtained in the same manner as in Example 5, except that no wax was used. The specific gravity and moisture content of this compressed product are shown in Table 1.
[0100] The compressed product was then used to produce a fiber board in the same manner as in Example 5. The thickness and density of the fiber board of the comparative example were the same as those of the fiber board of Example 1.
[0101] 2. Test (1) Water Resistance The compressed product was immersed in water at 25°C. The compressed product was held at a depth of 3 cm. 10 seconds after immersion, the compressed product was removed from the water and the swelling state of the compressed product (shape of the compressed product) was observed. The observation results were classified according to the following evaluation criteria to evaluate water resistance.
[0102] <Evaluation criteria> A: No swelling observed (shape maintained) B: Slight swelling observed (shape partially distorted) C: More swelling observed than B (shape distorted).
[0103] (2) Strength The bending strength of the fiber board was measured in accordance with JIS A 5905 Fiberboard. The measured values were classified according to the following evaluation criteria, and the strength was evaluated.
[0104] <Evaluation Criteria> A: Bending strength is 25 MPa or more. B: Bending strength is 20 MPa or more and less than 25 MPa. C: Bending strength is less than 20 MPa.
[0105] (3) Surface Smoothness The center line average roughness Ra of the fiber board was measured in accordance with JIS B 0601 Surface Roughness. The measured values were classified according to the following evaluation criteria to evaluate the surface smoothness.
[0106] <Evaluation Criteria> A: Ra is 5 μm or less B: Ra is more than 5 μm and 15 μm or less C: Ra is more than 15 μm.
[0107]
[0108] The strength of the fiber boards of Examples 1 to 7 was superior to that of the Comparative Example, confirming that adding wax to the crushed material of palm plants is effective.
[0109] Furthermore, the surface smoothness of the fiberboards in Examples 1 to 5 and 7 was superior to that in Example 6, confirming that a suitable chip content of 70 mass % or more is effective.
[0110] Furthermore, the water resistance of the compressed products of Examples 1 to 6 was superior to that of Example 7, confirming that a wax addition rate of more than 0.05 mass% was effective. Note that, since no wax was used in the Comparative Example, it was confirmed that the water resistance of the compressed products was worse than that of Example 7.
[0111] REFERENCE SIGNS LIST 1 Compressed material for fiberboard production (compressed material) 2 Wood fiber 3 Molding machine 4 Die 40 Through hole 41 First surface 42 Second surface 5 Compression roller
Claims
1. A method for manufacturing a fiber board, comprising: a compressing step in which a mixture of crushed palm plant material and wax is compressed to obtain a compressed material; a steaming and defibrating step in which the compressed material is steamed and defibrated to obtain wood fibers; a forming step in which an adhesive is added to the wood fibers and molded to obtain a mat-like molded product; and a hot-pressing step in which the mat-like molded product is heated and pressed.
2. The method for producing a fiber board according to claim 1, wherein the pulverized material is obtained by pulverizing the palm plant and then classifying it to reduce the amount of parenchyma tissue.
3. The method for producing a fiber board according to claim 1, wherein the pulverized material contains chips having a length of 0.6 mm or more and 50.0 mm or less and an outer diameter of 0.10 mm or more and 2.00 mm or less in an amount of 70 mass % or more relative to the total mass of the pulverized material.
4. A method for producing a fiberboard according to any one of claims 1 to 3, using a molding machine equipped with a die having a first surface, a second surface opposite the first surface, and through holes penetrating from the first surface to the second surface, and a compression roller that rolls on the first surface, supplying the mixture to the first surface, forcing the mixture into the through holes with the compression roller to compress it, thereby forming the compressed product, and extruding the compressed product from the second surface.
5. Compressed material for fiberboard production, which is a compressed mixture of crushed palm plant material and wax.