Manufacturing method of laminated lumber

Abstract

To provide a laminated timber having higher hardness and strength even when made from the trunks of oil palm, and a method for manufacturing the laminated timber. [Solution] The laminated lumber S is formed by compressing a laminate L made of multiple stacked oil palm veneers T, and each veneer T is impregnated with bacterial cellulose. The manufacturing method includes a sawing process (1) in which an oil palm trunk P is sawn to obtain veneers, a pre-treatment drying process (2) in which the veneers T are dried, an impregnation process (3) in which the veneers T are impregnated with the impregnation liquid by immersing them in an impregnation liquid containing bacterial cellulose, a pressing process (4) in which the laminate L made of multiple stacked veneers T is compressed for a required time with a press machine, and a finish drying process (5) in which it is then dried. It also includes a bacterial cellulose production process (A) in which bacterial cellulose is produced from the scraps Pa of the oil palm trunk P including the surrounding materials obtained in the sawing process.

Description

[Technical field]

[0001] This invention uses the trunk (OPT) of the oil palm. Collection The present invention relates to a method for manufacturing laminated timber. [Background technology]

[0002] In Southeast Asia, especially in Indonesia and Malaysia, oil palm plantations have developed on a large scale, and the harvesting period for oil palm fruit bunches (FFB) is about 25 to 30 years, and as they are cut down at that age, large amounts of old oil palm trunks (OPT) are produced along with the oil palm foliage (OPF). Previously, these were left abandoned within the plantations or disposed of by burning, but in recent years, some effective use has been made of them.

[0003] Conventionally, in the use of oil palm trunks (OPT), for example, a laminated lumber technology described in Patent Publication No. 6164649 (Patent Document 1) is known. This laminated lumber is manufactured as follows. The trunks of felled oil palms are cut to a predetermined length, and a peeling board method using cutting equipment such as a rotary lathe or slicer is used to obtain continuous oil palm peeled boards of a predetermined thickness, which are then cut to a predetermined length to obtain oil palm veneer. Next, these oil palm veneers are stacked alternately so that the fiber directions cross. Then, the laminate constructed in this way is subjected to a predetermined temperature and a predetermined pressing force using a hot press machine, and the laminated lumber is bonded by self-adhesion to obtain a laminated lumber. Generally, oil palm veneer obtained from oil palm trunks has the disadvantages of being low density and weak hardness and strength, unlike veneer made from materials such as lauan. However, in this conventional technology, a hot press machine is used to apply a specified temperature and pressure to compress the veneer, increasing its density and improving its 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] Incidentally, the conventional laminated lumber described above is produced by applying a certain temperature and pressure using a hot press machine, so the veneer itself is compressed and its density is high, but since it is originally oil palm veneer obtained from the trunks of oil palms, 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 any adhesive, the adhesive strength is accordingly weak, and in this respect too, the strength is not necessarily sufficient for laminated lumber. The present invention was made in consideration of the above problems, and has been developed to improve the hardness and strength of the trunks of oil palm trees. Collection The object of the present invention is to provide a method for manufacturing lumber. [Means for solving the problem]

[0006] To achieve the above object, the laminated wood of the present invention In the manufacturing method of the Laminated timber is made by compressing a laminate of multiple oil palm veneers. Each veneer is impregnated with bacterial cellulose. It is desirable to laminate oil palm veneer alternately so that the fiber directions cross.

[0007] Here, bacterial cellulose is also called nanofiber bacterial cellulose (NFBC), which is cellulose mainly produced by acetic acid bacteria. It is a fine fiber with a width of about tens of nanometers that does not contain lignin or hemicellulose, and has a highly developed network structure, which gives it high mechanical strength. It also has properties such as biodegradability. For this reason, it is attracting attention as a material that can be used in various fields. The present inventors focused on this bacterial cellulose and discovered that it can be used by impregnating it into oil palm veneer.

[0008] Bacterial cellulose (NFBC) is synthesized by acetic acid bacteria (Gluconacetobacter), a typical obligate aerobic bacterium. Acetic acid bacteria secrete bacterial cellulose of about 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 lumber of the present invention is impregnated with this bacterial cellulose (NFBC), which can further increase its hardness and strength. In particular, the impregnated bacterial cellulose functions as an adhesive between veneers, which significantly increases the adhesive strength between the veneers, further improving the strength. This makes the laminated lumber 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, thereby ensuring improved hardness and strength.

[0011] In addition, as necessary, the bacterial cellulose is mainly biosynthesized by acetic acid bacteria using sugars produced from the trunks of oil palms as a raw material. As described later, since oil palm trunks (OPT) contain a large amount of sugar, bacterial cellulose can be obtained with high efficiency. Since the bacterial cellulose used is produced from the trunks of oil palms, 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. In addition, since the bacterial cellulose is produced from the same sugars produced from the trunks of oil palms as the veneer, it can be produced at the oil palm processing site, which not only provides high production efficiency, but also reduces processing and transportation costs compared to procuring it elsewhere, resulting in high economic benefits.

[0012] To manufacture such laminated lumber The method for producing laminated wood of the present invention is a method for producing laminated wood formed by compressing a laminate of multiple oil palm veneers, comprising the steps of: A sawing process in which oil palm trunks are sawn into veneer boards; a pre-treatment drying process for drying the veneer obtained in the sawing process; The veneer dried in the pre-treatment drying step is immersed in an impregnating solution containing bacterial cellulose biosynthesized by acetic acid bacteria using sugars as a raw material, and the impregnating solution is applied to the veneer. Keep the temperature at 40℃~50℃ an impregnation step of impregnating; The veneer obtained in the impregnation process Without cooling, multiple layers are stacked. a compression step in which the laminate is compressed for a required time by a press machine to bond adjacent veneers together; The pressure bonding step is followed by a finish drying step. It is desirable to laminate oil palm veneer alternately so that the fiber directions cross.

[0013] Bacterial cellulose is impregnated into dried oil palm veneers, and multiple layers of this veneer are laminated together and pressed together, 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, so the adhesive strength between the veneers is extremely high, further improving the strength in this respect as well. This makes it useful for a variety of applications, including building materials.

[0014] If necessary, the sawing process is configured to saw the barked tree trunk to separate it into a square timber containing the core of the tree trunk and a surrounding timber, and then saw the square timber to obtain veneer of a specified size. Since veneer is obtained from a square timber containing the core of the tree trunk, it is relatively free from bending even when dried, making it easier to manufacture and improving the quality of the product.

[0015] If necessary, the method is configured to include a bacterial cellulose production step for producing the bacterial cellulose from the scraps of the oil palm trunk including the surrounding wood obtained in the sawing step. The oil palm trunk (OPT) has a high moisture content of 60-75% by weight of the total weight, and the juice obtained by squeezing this trunk contains sugars such as sucrose, glucose, and fructose at high concentrations of 20-100 mg per mL. Therefore, bacterial cellulose can be obtained with high efficiency from the oil palm trunk.

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

[0017] In this case, if necessary, the bacterial cellulose production step is A culture generating step of preparing a culture containing acetic acid bacteria using fruits obtained from an oil palm fruit bunch; A juicing process in which the oil palm trunk scraps including the surrounding wood obtained in the lumbering process are processed with a juicing machine to obtain a juice; a decomposition step of decomposing the juice obtained in the juice squeezing 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; and an extraction step for extracting bacterial cellulose from the mixed liquid fermented in the fermentation step.

[0018] As a result, a culture containing acetic acid bacteria is created using fruits obtained from the fruit bunches of oil palm, and this culture acts as a so-called seed culture, synthesizing cellulose using carbohydrates such as glucose, which are monosaccharides in the secondary liquid, as a carbon source in the fermentation process. Glucose taken up by the bacteria is converted into glucan chains via glucose-6-phosphate, glucose-1-phosphate, and uridine diphosphate-glucose. In this case, the culture acting as the seed culture is obtained from the fruit bunches of oil palm, which can improve production efficiency. Effect of the Invention

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

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

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a laminated lumber and a method for manufacturing a laminated lumber according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. As shown in Figure 1, the laminated timber S of the embodiment of the present invention is formed by compressing a laminate L (Figure 2) in which multiple oil palm veneers T are stacked, and each veneer T is impregnated with bacterial cellulose. The oil palm veneers are stacked alternately so that their fiber directions cross. In the 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 the embodiment, bacterial cellulose is synthesized mainly by acetic acid bacteria using sugars produced from the trunks of oil palm trees. Here, bacterial cellulose is also called nanofiber bacterial cellulose (NFBC). This bacterial cellulose is cellulose produced mainly by acetic acid bacteria, and is a fine fiber with a width of about several tens of nanometers that does not contain lignin or hemicellulose, and has a highly developed network structure, so it exhibits high mechanical strength. It also has 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 about 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 method for manufacturing a laminated lumber according to an embodiment of the present invention will be described. As shown in FIG. 2, this method for manufacturing a laminated lumber S is a method for manufacturing a laminated lumber S formed by compressing a laminate L in which a plurality of oil palm veneers T are laminated, and is configured to include a sawing process (1) in which an oil palm trunk P is sawn to obtain a veneer T, a pre-treatment drying process (2) in which the veneer T obtained in the sawing process is dried, an impregnation process (3) in which the veneer T dried in the pre-treatment drying process is immersed in an impregnation liquid containing bacterial cellulose biosynthesized by acetic acid bacteria using sugars as a raw material to impregnate the veneer T with the impregnation liquid, a pressing process (4) in which the laminate L in which a plurality of veneers T obtained in the impregnation process are laminated is compressed by a press machine for a required time to bond adjacent veneers T together, and a finishing drying process (5) in which the veneer T is dried after the pressing process. The bacterial cellulose used in the impregnation process is that produced in a bacterial cellulose production process (A) provided separately. Each process will be described in detail below. First, the bacterial cellulose production step (A) will be described.

[0025] (A) Bacterial cellulose production process This is a process for producing bacterial cellulose from scraps Pa of oil palm trunk P including surrounding materials 2 obtained in the sawing process described below, and as shown in Figure 3, it is composed of a culture production process (A-1) in which a culture containing acetic acid bacteria is prepared using fruits (FFB) obtained from the fruit bunches of oil palm, a juicing process (A-2) in which the scraps Pa of oil palm trunk P including surrounding materials 2 obtained in the sawing process described below are processed with a juicing machine to obtain a squeezed liquid, a decomposition process (A-3) in which the squeezed liquid obtained in the juicing process is decomposed to obtain a secondary liquid containing a large amount of monosaccharides, a fermentation process (A-4) in which the mixed liquid obtained by mixing the culture and the secondary liquid is put into a fermentation tank and fermented for a required time, and an extraction process (A-5) in which bacterial cellulose is extracted from the mixed liquid fermented in the fermentation process. The process will be described in detail below.

[0026] (A-1) Culture generation process A culture containing acetic acid bacteria is created using the fruit (FFB) obtained from the fruit bunch of the oil palm. Specifically, for example, the skin of the fruit (FFB) is peeled, the peeled skin is liquefied in a mixer, and placed in an open container, sugar and water are added, and the mixture is stored in a dark room at room temperature. Acetic acid bacteria are naturally present in the fruit, and examples of the species include Gluconacetobacter lycephadiens and Acetobacter xylinum. Bacterial cellulose is synthesized from these acetic acid bacteria and appears as a membrane on the surface of the solution in the container. This membrane-like bacterial cellulose is extracted to create a culture. The culture contains useful acetic acid bacteria.

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

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

[0029] (A-3) Decomposition process The juice is boiled down or otherwise processed to hydrolyze as many polysaccharides and oligosaccharides, such as starch, contained in the juice into monosaccharides, such as glucose, fructose, and galactose, as much as possible, 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 a required time. Sterilized water is added to the secondary liquid to make a medium, and this medium and the culture are mixed to make a liquid. In this case, the culture that functions as a seed fungus is obtained from the fruit bunch of oil palm, so that the production efficiency can be improved accordingly. In the embodiment, a fermentation tank with a capacity of, for example, 300 liters is used, and the secondary liquid (90 kg, sugar content 80 w%) is added to it, sterilized water (210 liters) is added to make a medium (300 liters, sugar content 30 w%), and the culture (6 kg) is added to make a mixed liquid (acetic acid bacteria 1 to 2 w%). For example, fermentation is performed at a temperature range of 50°C to 60°C for 70 to 75 hours with stirring (1 RPM).

[0031] (A-5) Extraction process Bacterial cellulose is extracted from the mixed liquid fermented in the fermentation process. In the embodiment, 18 kg to 20 kg of paste-like bacterial cellulose (NFBC) was obtained per tank from the fermented mixed liquid. In this case, since oil palm trunk P, which has a high sugar content, is used, bacterial cellulose can be obtained with high efficiency. In this case, bacterial cellulose is produced using scraps Pa made of the same oil palm trunk P as the veneer T, so bacterial cellulose can be produced at the oil palm processing site. In particular, since at least the surrounding material 2 is used, there is no waste and production efficiency is good, 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 manufacturing laminated timber S from oil palm trunks P. (1) Lumber processing First, in a processing factory, the bark is removed, and the bark-removed trunk P is sawn into a block 1 including the core of the trunk P and a surrounding block 2 surrounding the block 1. The block 1 is then sawn into a veneer T of a predetermined size.

[0033] In the embodiment, the trunk P (OPT) of a felled old oil palm tree is cut into a length of 4,000 mm, for example, from a diameter of 300 to 450 mm and a length of 12,000 mm (weight: 3,400 kg). The weight values ​​listed below are the weight per three cut trunks P of 4,000 mm length (3,400 kg). The bark (650 kg), a square timber 1 (1,000 kg) sawn to a thickness of 150 mm, width of 100 mm, and length of 4,000 mm around the core, and surrounding material 2 (1,400 kg) around the square timber 1 are obtained. The bark is chipped. The square timber 1 is sawn into multiple veneers T of a thickness of 20 mm, width of 100 mm, and length of 4,000 mm. The surrounding material 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, etc. The surrounding material 2 is the end material 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 by a dryer 10. As the dryer 10, a well-known dryer such as a pressure dryer, a steam dryer, a hot water dryer, or an electric dryer can be used. As the steam dryer, a superheated steam dryer can be used, 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 a temperature higher than 100°C. In the 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 about 15w% over about 8 hours. In this case, the veneer T is obtained from a square timber 1 including the core part of the trunk P, so that it is relatively less curved even when dried, making subsequent processing easier.

[0035] (3) Impregnation process The veneer T dried in the pre-treatment drying step is immersed in an impregnation liquid containing bacterial cellulose to impregnate the veneer T with the impregnation liquid. In the embodiment, the bacterial cellulose in the paste form produced in the bacterial cellulose production step is used. Then, this bacterial cellulose (0.6 ml) is mixed with water and dried. 3 ) and water (5.4m 3 ) and impregnation liquid (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 liquid 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 liquid 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 as is 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 type, to bond adjacent veneers T together. If unnecessary bacterial cellulose or air seeps out during compression, 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 since the bacterial cellulose functions as an adhesive, the veneers are able to bond together 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 naturally dried. This completes the laminated lumber S.

[0039] The laminated lumber S manufactured in this manner 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 the veneers T, which significantly increases the adhesive strength between the veneers T, further improving the strength. This makes the laminated lumber S useful for a variety of applications, including building materials.

[0040] When using this laminated lumber S, it can be used as is or cut appropriately. For example, 2 ), structural materials (480m 3 ), multi-stage feeding equipment structural material (250m 3 ), roofing material (96m 3 ) and wall material (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 Scrap 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) Lumber processing (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 a method for manufacturing a laminated lumber, a laminated lumber is manufactured by compressing a laminated body in which a plurality of oil palm veneers are laminated, A sawing process in which oil palm trunks are sawn into veneer boards; a pre-treatment drying process for drying the veneer obtained in the sawing process; 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, and the veneer is impregnated with the impregnation solution while maintaining the temperature at 40°C to 50°C; a pressure bonding step in which the veneers obtained in the impregnation step are stacked as they are without cooling, and the stacked body is compressed by a press machine for a required time to bond adjacent veneers to each other; A finishing drying step for drying the product after the pressing step is provided. The above sawing process is as follows: The bark of the oil palm tree is removed and the trunk is sawn into a square timber including the core of the trunk and a surrounding timber including the periphery of the square timber. The square timber is then sawn into a veneer of a predetermined size. A method for manufacturing laminated lumber, comprising a bacterial cellulose production process for producing the bacterial cellulose from scraps of oil palm trunks including surrounding wood obtained in the sawing process.

2. The bacterial cellulose production process includes: A culture generating step of preparing a culture containing acetic acid bacteria using fruits obtained from an oil palm fruit bunch; A juicing process in which the oil palm trunk scraps including the surrounding wood obtained in the sawing process are processed with a juicing machine to obtain juice; a decomposition step of decomposing the juice obtained in the juice squeezing 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; 2. The method for manufacturing a laminated lumber according to claim 1, further comprising an extraction step of extracting bacterial cellulose from the mixed liquid fermented in the fermentation step.

3. The method for manufacturing a laminated timber as described in claim 2, characterized in that the content of the bacterial cellulose in the laminated timber is 40 to 50 parts by mass when the whole is taken as 100 parts by mass, and the bending Young's modulus is 14.4 GPa ± 1.5.

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