Manufacturing method of laminated lumber

Abstract

To provide laminated lumber much harder and stronger even when using a trunk of oil palm, and a manufacturing method of the laminated lumber.SOLUTION: Laminated lumber S is formed by compressing laminated bodies L made through laminating a plurality of single plates T of oil palm, wherein bacteria cellulose is impregnated in each of the single plates T. A manufacturing method is provided with: a lumbering process (1) of acquiring a single plate through lumbering a trunk P of the oil palm; a pre-treatment drying process (2) of drying the single plate T; an impregnating process (3) of impregnating the single plate T with impregnating solution including the bacteria cellulose; a crimping process (4) of compressing the laminated body L obtained by laminating the plurality of single plates T for a required time using a press machine; and a finish drying process (5) of drying thereafter. Also, it is provided with a bacteria cellulose production process (A) of producing bacteria cellulose from chips Pa of the trunk P of the oil palm including surrounding materials acquired in the lumbering process.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a laminated timber made from oil palm trunks (OPT) and a method for manufacturing such laminated timber. [Background technology]

[0002] In Southeast Asia, particularly in Indonesia and Malaysia, oil palm plantations have developed on a large scale, and the harvesting period for oil palm fruit bunches (FFB) is approximately 25 to 30 years, after which the trees are cut down, resulting in large amounts of old oil palm trunks (OPT) along with their stems and leaves (OPF). Previously, these were left abandoned within the plantations or disposed of by burning, but in recent years, some of them have begun to be used effectively.

[0003] Conventionally, the use of oil palm trunks (OPT) has been known, for example, through the use of laminated lumber technology described in Patent Publication No. 6164649 (Patent Document 1). This laminated lumber is manufactured as follows: The trunks of felled oil palms are cut to a predetermined length, and a peeling method using cutting equipment such as a rotary lathe or slicer is used to obtain oil palm continuous peeled boards of a predetermined thickness. These oil palm continuous peeled boards are then cut to a predetermined length to obtain oil palm veneers. Next, these oil palm veneers are stacked alternately so that the fiber directions cross. The laminate thus constructed is then subjected to a predetermined temperature and pressure using a hot press machine, and the laminate is bonded by self-adhesion to obtain a laminated lumber. Generally, oil palm veneer obtained from oil palm trunks has the disadvantage of being low in density and weak in hardness and strength, unlike veneers made from materials such as lauan.However, this conventional technology uses a hot press machine to apply a specified temperature and pressure to compress the veneer, increasing its density and hardness and strength. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6164649 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional laminated lumber described above is produced by applying a predetermined temperature and pressure using a hot press, which means that the veneer itself is compressed and its density is high. However, since it is originally oil palm veneer obtained from the trunks of oil palm trees, there are limitations in terms of hardness and strength, and there is a problem that the hardness and strength are not necessarily sufficient for laminated lumber. In particular, since the veneers are joined by self-adhesion without using adhesive, the adhesive strength is weak, and in this respect too, the strength is not necessarily sufficient for laminated lumber. The present invention has been made in consideration of the above-mentioned problems, and aims to provide laminated timber that has even greater hardness and strength even when made from oil palm trunks, and a method for manufacturing such laminated timber. [Means for solving the problem]

[0006] To achieve the above object, the laminated wood of the present invention is formed by compressing a laminated body in which multiple oil palm veneers are laminated, Each veneer is impregnated with bacterial cellulose. It is desirable to stack oil palm veneers alternately so that the fiber directions cross.

[0007] Bacterial cellulose, also known as nanofiber bacterial cellulose (NFBC), is a type of cellulose primarily produced by acetic acid bacteria. It consists of fine fibers approximately tens of nanometers wide that do not contain lignin or hemicellulose and have a highly developed network structure, resulting in high mechanical strength. It also possesses properties such as biodegradability. Therefore, it has attracted attention as a material that can be utilized in a variety of fields. The present inventors focused on bacterial cellulose and discovered its use by impregnating oil palm veneers.

[0008] Bacterial cellulose (NFBC) is synthesized by acetic acid bacteria (Gluconacetobacter), a typical obligate aerobic bacterium. Acetic acid bacteria secrete bacterial cellulose of approximately 50 to 100 nm outside the bacterial cell. Normally, acetic acid bacteria synthesize cellulose using carbohydrates such as glucose as a carbon source. Glucose taken up into the bacterial cell is converted into glucan chains via glucose-6-phosphate, glucose-1-phosphate, and uridine diphosphate-glucose.

[0009] As a result, the laminated timber of the present invention is impregnated with bacterial cellulose (NFBC), which can further increase its hardness and strength. In particular, the impregnated bacterial cellulose functions as an adhesive between veneers, significantly increasing the adhesive strength between the veneers, further improving strength. This makes the laminated timber useful for a variety of applications, including building materials.

[0010] If necessary, the bacterial cellulose content is 40 to 50 parts by mass relative to 100 parts by mass of the total, and the Young's modulus of bending is 14.4 GPa±1.5, which can reliably improve hardness and strength.

[0011] Furthermore, if necessary, the bacterial cellulose is biosynthesized primarily by acetic acid bacteria using sugars produced from oil palm trunks. As described below, oil palm trunks (OPT) contain a high sugar content, allowing bacterial cellulose to be obtained with high efficiency. Because the bacterial cellulose used is produced from oil palm trunks, it blends well with the veneer, and the bacterial cellulose functions as an adhesive, allowing the veneer to bond and maintain its strength without the need for a separate adhesive. Furthermore, because the bacterial cellulose is produced from the same sugars produced from oil palm trunks as the veneer, it can be produced at the oil palm processing site, resulting in high production efficiency and economic benefits, such as reduced processing and transportation costs compared to sourcing it elsewhere.

[0012] In order to solve the above problems, the manufacturing method of the laminated wood of the present invention is a manufacturing method of laminated wood formed by compressing a laminated body in which a plurality of oil palm veneers are laminated, The sawing process involves sawing the trunks of oil palm trees to obtain veneers. a pre-treatment drying step for drying the veneer obtained in the sawing step; an impregnation step in which the veneer dried in the pre-treatment drying step is immersed in an impregnation solution containing bacterial cellulose biosynthesized by acetic acid bacteria using sugars as a raw material, thereby impregnating the veneer with the impregnation solution; a pressure-bonding step in which the laminate obtained by the impregnation step is compressed by a press machine for a required time to bond adjacent veneers together; The pressure bonding process is followed by a finishing drying process. It is desirable to stack oil palm veneers alternately so that the fiber directions cross.

[0013] Dried oil palm veneers are impregnated with bacterial cellulose, and multiple layers of this veneer are laminated together under pressure, with the bacterial cellulose acting as an adhesive to bond the veneers together. The bacterial cellulose makes the finished laminated lumber even harder and stronger. In particular, the bacterial cellulose acts as an adhesive between the veneers, significantly increasing the adhesive strength between them, further improving strength. This makes it useful for a variety of applications, including building materials.

[0014] If necessary, the sawing process involves sawing the barked trunk into a square timber containing the core of the trunk and a surrounding piece of timber, and then sawing the square timber to obtain veneer of a specified size. Because veneer is obtained from a square timber containing the core of the trunk, it is relatively stable even when dried, making it easier to manufacture and improving product quality.

[0015] Furthermore, if necessary, the system may include a bacterial cellulose production step for producing the bacterial cellulose from the scraps of oil palm trunks, including the surrounding wood, obtained in the sawing process. Oil palm trunks (OPT) have a high moisture content, with water content of 60-75% of the total weight, and the juice obtained by squeezing these trunks contains high concentrations of sugars such as sucrose, glucose, and fructose, at 20-100 mg per mL. This allows bacterial cellulose to be obtained highly efficiently from oil palm trunks.

[0016] The bacterial cellulose used is made from oil palm trunks, so it blends well with the veneer, and since the bacterial cellulose functions as an adhesive, the veneer can be bonded and maintain its strength without the need for a separate adhesive. Furthermore, because the bacterial cellulose is made from the same oil palm trunk scraps as the veneer, it can be produced at the oil palm processing site. In particular, since at least the surrounding material is used, there is no waste, and production efficiency is high. Furthermore, compared to procuring it from elsewhere, processing costs and transportation costs can be reduced, resulting in high economic benefits.

[0017] In this case, if necessary, the bacterial cellulose production step may be a culture generating step of preparing a culture containing acetic acid bacteria using fruits obtained from oil palm fruit bunches; A juicing process in which the oil palm trunk scraps including the surrounding wood obtained in the sawing process are processed using a juicing machine to obtain sap; a decomposition step of decomposing the juice obtained in the juicing step to obtain a secondary liquid rich in monosaccharides; a fermentation step in which a mixed liquid obtained by mixing the culture and the secondary liquid is placed in a fermentation tank and fermented for a required time; and an extraction step for extracting bacterial cellulose from the mixed liquid fermented in the fermentation step.

[0018] This allows the creation of a culture containing acetic acid bacteria using fruits obtained from the fruit bunches of oil palm. This culture acts as a so-called seed culture and synthesizes cellulose using carbohydrates such as glucose, which are monosaccharides in the secondary liquor, as a carbon source during the fermentation process. The glucose taken up by the fungus is converted into glucose-6-phosphate, glucose-1-phosphate, and uridine diphosphate-glucose to synthesize glucan chains. In this case, the culture that acts as the seed culture is obtained from the fruit bunches of oil palm, which increases production efficiency. [Effects of the Invention]

[0019] According to the present invention, the laminated timber is impregnated with bacterial cellulose (NFBC), which can further increase its hardness and strength. In particular, the impregnated bacterial cellulose functions as an adhesive between veneers, significantly increasing the adhesive strength between the veneers, further improving strength. This makes the laminated timber useful for a variety of applications, including building materials. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram showing a laminated wood according to an embodiment of the present invention; [Figure 2] 1A to 1C are diagrams showing steps for manufacturing a laminated wood according to an embodiment of the present invention. [Figure 3] FIG. 2 is a diagram showing more detailed steps of the bacterial cellulose production step in the process for producing laminated wood according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a laminated lumber and a method for manufacturing a laminated lumber according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. As shown in Figure 1, the laminated timber S according to an embodiment of the present invention is formed by compressing a laminate L (Figure 2) made up of multiple oil palm veneers T, each of which is impregnated with bacterial cellulose. The oil palm veneers are also stacked alternately so that their fiber directions cross. In this embodiment, the bacterial cellulose content is 40 to 50 parts by mass when the total is 100 parts by mass, and the bending Young's modulus is 14.4 GPa ± 1.5.

[0022] In an embodiment, bacterial cellulose is biosynthesized primarily by acetic acid bacteria using sugars produced from the trunks of oil palm trees. Here, bacterial cellulose is also known as nanofiber bacterial cellulose (NFBC). This bacterial cellulose is primarily produced by acetic acid bacteria, and consists of fine fibers with a width of several tens of nanometers that do not contain lignin or hemicellulose. Its highly developed network structure gives it high mechanical strength. It also has other properties, such as biodegradability.

[0023] Bacterial cellulose (NFBC) is synthesized by acetic acid bacteria (Gluconacetobacter), a typical obligate aerobic bacterium. Acetic acid bacteria secrete bacterial cellulose of approximately 50 to 100 nm outside the bacterial cell. Normally, acetic acid bacteria synthesize cellulose using carbohydrates such as glucose as a carbon source. Glucose taken up into the bacterial cell is converted into glucan chains via glucose-6-phosphate, glucose-1-phosphate, and uridine diphosphate-glucose.

[0024] Next, a manufacturing method for laminated lumber according to an embodiment of the present invention will be described. As shown in Figure 2, this manufacturing method for laminated lumber involves compressing a laminate L, which is made by stacking multiple oil palm veneers T, to produce a laminated lumber S. The manufacturing method includes the following steps: a sawing process (1) in which an oil palm trunk P is sawn to obtain veneers T; a pre-treatment drying process (2) in which the veneers T obtained in the sawing process are dried; an impregnation process (3) in which the dried veneers T are immersed in an impregnation solution containing bacterial cellulose biosynthesized by acetic acid bacteria using sugars as a raw material, thereby impregnating the veneers T with the impregnation solution; a pressure bonding process (4) in which the laminate L, made by stacking multiple veneers T obtained in the impregnation process, is compressed in a press machine for a required time to bond adjacent veneers T together; and a finish drying process (5) in which the laminated lumber S is dried after the pressure bonding process. The bacterial cellulose used in the impregnation process is that produced in a separate bacterial cellulose production process (A). Each process will be described in detail below. First, the bacterial cellulose production step (A) will be explained.

[0025] (A) Bacterial cellulose production process This is a process for producing bacterial cellulose from scraps (Pa) of oil palm trunks (P) containing surrounding wood (2) obtained in the sawing process described below. As shown in Figure 3, it comprises a culture production process (A-1) in which a culture containing acetic acid bacteria is produced using fruit (FFB) from oil palm fruit bunches, a juicing process (A-2) in which the scraps (Pa) of oil palm trunks (P) containing surrounding wood (2) obtained in the sawing process described below are processed in a juice extractor to obtain a squeezed juice, a decomposition process (A-3) in which the squeezed juice obtained in the juicing process is decomposed to obtain a secondary liquid rich in monosaccharides, a fermentation process (A-4) in which the mixture obtained by mixing the culture and the secondary liquid is placed in a fermentation tank and fermented for a required time, and an extraction process (A-5) in which bacterial cellulose is extracted from the fermented mixture. These are explained in detail below.

[0026] (A-1) Culture generation process Cultures containing acetic acid bacteria are created using fruit (FFB) obtained from oil palm fruit bunches. Specifically, the fruit (FFB) is peeled, liquefied in a blender, and placed in an open container with sugar and water, then stored in a dark room at room temperature. Fruit naturally contains acetic acid bacteria, such as Gluconacetobacter lycephadiens and Acetobacter xylinum. These acetic acid bacteria synthesize bacterial cellulose, which appears as a membrane on the surface of the solution in the container. This membrane-like bacterial cellulose is then extracted to form a culture. The culture contains useful acetic acid bacteria.

[0027] (A-2) Juicing process Here, scraps Pa of oil palm trunks P including surrounding material 2 obtained in the sawing process described below are used. In addition to the surrounding material 2, scraps Pa may also be used that cannot be processed into veneer T, so in short, any form of scraps may be used as long as oil palm trunks P are used. In the embodiment, the surrounding material 2 is mainly used as scraps Pa, which are processed using a well-known juice extractor to obtain juice.

[0028] Oil palm trunk P (OPT) has a high moisture content, with 60 to 75% of its total weight being water, and the juice obtained by squeezing this trunk P contains high concentrations of sugars such as sucrose, glucose, and fructose, at 20 to 100 mg per mL. In this embodiment, for example, a squeezed juice with a moisture content of 75 wt % and a sugar content of 20 wt % and a residue (moisture content of 50 wt %) are obtained. The residue can be dried, for example, and used as fuel.

[0029] (A-3) Decomposition process The juice is boiled down to hydrolyze as many polysaccharides and oligosaccharides as possible, such as starch, into monosaccharides such as glucose, fructose, and galactose, to obtain a paste-like secondary liquid.

[0030] (A-4) Fermentation process The mixed liquid obtained by mixing the culture and the secondary liquid is placed in a fermentation tank and fermented for the required time. Sterilized water is added to the secondary liquid to form a medium, and this medium and the culture are mixed to form a liquid mixture. In this case, the culture that functions as the seed culture is obtained from oil palm fruit bunches, which improves production efficiency. In this embodiment, a fermentation tank with a capacity of, for example, 300 liters is used, and the secondary liquid (90 kg, sugar content 80 wt%) is added to it, and sterilized water (210 liters) is added to form a medium (300 liters, sugar content 30 wt%). The culture (6 kg) is then added to form a mixed liquid (acetic acid bacteria content 1-2 wt%). Fermentation is carried out, for example, at a temperature ranging from 50°C to 60°C for 70-75 hours with stirring (1 RPM).

[0031] (A-5) Extraction process Bacterial cellulose is extracted from the fermented mixture in the fermentation process. In this embodiment, 18 to 20 kg of paste-like bacterial cellulose (NFBC) was obtained per tank from the fermented mixture. In this case, the sugar-rich oil palm trunk P is used, allowing bacterial cellulose to be obtained with high efficiency. In this case, bacterial cellulose is produced using scrap wood Pa made from the same oil palm trunk P as the veneer T, so bacterial cellulose can also be produced at the oil palm processing site. In particular, since at least the surrounding material 2 is used, there is no waste, production efficiency is high, and compared to procuring it elsewhere, processing costs, transportation costs, etc. can be reduced, resulting in high economic benefits.

[0032] Next, using Figure 2, we will explain the main process for producing laminated timber S from oil palm trunks P. (1) Lumbering process First, in a processing factory, the bark is removed, and the barked trunk P is sawn into a square timber 1 including the core portion of the trunk P and a surrounding timber 2 surrounding the square timber 1. The square timber 1 is then sawn to obtain a veneer T of a predetermined size.

[0033] In this embodiment, a trunk P (OPT) made from a felled old oil palm tree is cut into 4,000 mm lengths, for example, with a diameter of 300 to 450 mm and a length of 12,000 mm (weight: 3,400 kg). Note that the weight values ​​listed below are the weight per three 4,000 mm-long cut trunks P (3,400 kg). The resulting product is bark (650 kg), a lumber 1 (1,000 kg) sawn around the core to a thickness of 150 mm, width of 100 mm, and length of 4,000 mm, and a surrounding lumber 2 (1,400 kg) surrounding the lumber 1. The bark is chipped. The lumber 1 is sawn into multiple veneers T, each 20 mm thick, 100 mm wide, and 4,000 mm long. The surrounding lumber 2 is also sawn to a thickness of 20 mm, width of 100 mm or less, and length of 4,000 mm or less. The wood flour (350 kg) produced by this sawing process can be used for other purposes such as resin raw material. The surrounding material 2 is the offcuts Pa of the oil palm trunk P, and is used in the bacterial cellulose production process described above.

[0034] (2) Pre-treatment drying process The veneer T obtained in the sawing process is dried in a dryer 10. Examples of the dryer 10 that can be used include pressure dryers, steam dryers, hot water dryers, and electric dryers. A superheated steam dryer can be used as the steam dryer, which injects superheated steam higher than atmospheric pressure into a pressure vessel and dries the veneer T with high efficiency by setting the relative humidity up to 100% even at temperatures higher than 100°C. In this embodiment, a superheated steam dryer (steam temperature 400°C to 450°C) is used, and the moisture content of the veneer T is reduced to approximately 15 wt% over approximately 8 hours. In this case, since the veneer T is obtained from a block 1 containing the core portion of the tree trunk P, it is relatively less likely to bend even after drying, facilitating subsequent processing.

[0035] (3) Impregnation process The veneer T dried in the pre-treatment drying step is immersed in an impregnation solution containing bacterial cellulose to impregnate the veneer T with the impregnation solution. In this embodiment, the bacterial cellulose in the paste form produced in the bacterial cellulose production step is used. Then, this bacterial cellulose (0.6 m 3 ) and water (5.4m 3 ) and the impregnation solution (6m 3 The impregnation tank 11 (for example, height 1,500 mm, width 4,500 mm, length 4,500 mm, volume 30 m 3 The veneers T cooled to 75°C to 100°C were placed side by side in the impregnation tank 11, and an impregnation solution at 35°C to 50°C was poured into the impregnation tank 11, and the impregnation treatment was carried out for about 18 hours. During this time, the temperature of the impregnation solution in the impregnation tank 11 was maintained at 40°C to 50°C by a heater (not shown).

[0036] (4) Crimping process The veneers T obtained in the impregnation process are stacked one on top of the other without cooling. In this case, the oil palm veneers are stacked alternately so that the fiber directions cross. This laminate L is compressed for the required time using a well-known hydraulic press machine 12, for example, a 200-ton machine, to bond adjacent veneers T together. If unnecessary bacterial cellulose or air seeps out during the pressing process, it is removed by wiping it off as appropriate.

[0037] In this case, dried oil palm veneer T is impregnated with bacterial cellulose, and multiple layers of this veneer T are laminated together to form a laminate L, which bonds the veneers together. In this case, the bacterial cellulose used is made from the trunks of oil palm trees, so it blends well with the veneers, and the bacterial cellulose functions as an adhesive, allowing the veneers to bond and maintain their strength without the need for a separate adhesive.

[0038] (5) Finishing drying process After the compression and adhesion process, the wood is left to dry naturally, completing the laminated lumber S.

[0039] The laminated timber S manufactured in this way is impregnated with bacterial cellulose (NFBC), which can further increase its hardness and strength. In particular, the impregnated bacterial cellulose acts as an adhesive between the veneers T, significantly increasing the adhesive strength between the veneers T, further improving strength. This makes it useful for a variety of applications, including building materials.

[0040] When using this laminated timber S, it can be used as is or cut appropriately. For example, it can be used for a windowless chicken coop (1,540 m 2 ), structural materials (480m 3 ), multi-stage feeding equipment structural material (250m 3 ), roofing materials (96m 3 ) and wall materials (97m 3 ) etc.

[0041] It should be noted that the present invention is not limited to the above-described embodiments of the present invention, and those skilled in the art can easily make many modifications to these exemplary embodiments without substantially departing from the novel teachings and advantages of the present invention, and these many modifications are included within the scope of the present invention. [Explanation of symbols]

[0042] S Laminated wood T single board L laminate P tree trunk Pa scraps 1 timber 2 Surrounding material (A) Bacterial cellulose production process (A-1) Culture generation process (A-2) Juicing process (A-3) Decomposition process (A-4) Fermentation process (A-5) Extraction process (1) Lumbering process (2) Pre-treatment drying process (3) Impregnation process (4) Crimping process (5) Finishing drying process 10 Dryer 11 Impregnation tank 12 Press Machine

Claims

1. In laminated wood formed by compressing a laminate of multiple oil palm veneers, Glued laminated wood characterized in that each veneer is impregnated with bacterial cellulose.

2. The laminated wood according to claim 1, characterized in that the content of the bacterial cellulose is 40 to 50 parts by mass, with the total being 100 parts by mass, and the bending Young's modulus is 14.4 GPa ± 1.

5.

3. 3. The laminated wood according to claim 1, wherein the bacterial cellulose is biosynthesized mainly by acetic acid bacteria using sugars produced from the trunk of the oil palm as raw material.

4. In a method for manufacturing laminated lumber, a laminated lumber is manufactured by compressing a laminated body in which a plurality of oil palm veneers are laminated, The sawing process involves sawing the trunks of oil palm trees to obtain veneers. a pre-treatment drying step for drying the veneer obtained in the sawing step; an impregnation step in which the veneer dried in the pre-treatment drying step is immersed in an impregnation solution containing bacterial cellulose biosynthesized by acetic acid bacteria using sugars as a raw material, thereby impregnating the veneer with the impregnation solution; a pressure-bonding step in which the laminate obtained by the impregnation step is compressed by a press machine for a required time to bond adjacent veneers together; A method for manufacturing laminated wood, comprising a finishing drying process for drying the laminated wood after the pressing process.

5. The above sawing process is 5. A method for manufacturing laminated lumber according to claim 4, characterized in that the bark-stripped trunk is sawn to separate it into a square lumber containing the core portion of the trunk and a surrounding lumber consisting of the periphery of the square lumber, and the square lumber is sawn to obtain a veneer of a predetermined size.

6. A method for manufacturing laminated lumber as described in claim 5, characterized in that it includes a bacterial cellulose production process in which the bacterial cellulose is produced from scraps of oil palm trunks including surrounding wood obtained in the sawing process.

7. The bacterial cellulose production process includes: a culture generating step of preparing a culture containing acetic acid bacteria using fruits obtained from oil palm fruit bunches; A juicing process in which the oil palm trunk scraps including the surrounding wood obtained in the sawing process are processed using a juicing machine to obtain sap; a decomposition step of decomposing the juice obtained in the juicing step to obtain a secondary liquid rich in monosaccharides; a fermentation step in which a mixed liquid obtained by mixing the culture and the secondary liquid is placed in a fermentation tank and fermented for a required period of time; 7. The method for manufacturing laminated wood according to claim 6, further comprising an extraction step of extracting bacterial cellulose from the mixed liquid fermented in the fermentation step.

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