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WO2019168127A1 - Bois et procédé de production de bois - Google Patents

Bois et procédé de production de bois Download PDF

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Publication number
WO2019168127A1
WO2019168127A1 PCT/JP2019/007944 JP2019007944W WO2019168127A1 WO 2019168127 A1 WO2019168127 A1 WO 2019168127A1 JP 2019007944 W JP2019007944 W JP 2019007944W WO 2019168127 A1 WO2019168127 A1 WO 2019168127A1
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WIPO (PCT)
Prior art keywords
wood
raw material
solution
weight
solution containing
Prior art date
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PCT/JP2019/007944
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English (en)
Japanese (ja)
Inventor
祥生 堀川
梨乃 津島
達己 暮井
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Shokubai Co Ltd
Tokyo University of Agriculture and Technology NUC
Original Assignee
Nippon Shokubai Co Ltd
Tokyo University of Agriculture and Technology NUC
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Application filed by Nippon Shokubai Co Ltd, Tokyo University of Agriculture and Technology NUC filed Critical Nippon Shokubai Co Ltd
Priority to JP2020503632A priority Critical patent/JP6941328B2/ja
Publication of WO2019168127A1 publication Critical patent/WO2019168127A1/fr
Anticipated expiration legal-status Critical
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
    • B27K5/02—Staining or dyeing wood; Bleaching wood

Definitions

  • the present invention relates to wood containing lignin and cellulose, wood obtained by treating a wood raw material, and a method for producing the same.
  • Wood is widely used as a raw material for building materials, furniture, acoustic materials and paper.
  • Woody biomass is also used from the viewpoint of biorefinery such as bioethanol production.
  • lignin which is a constituent component of wood, is removed, and cellulose and hemicellulose are taken out.
  • the treatment for removing lignin is called pretreatment.
  • pretreatment techniques that destroy cells and wall layers have been reported so far.
  • pretreatment methods for removing lignin include physicochemical methods such as steam explosion treatment, acid treatment and alkali treatment, and biological methods utilizing lignin degrading enzymes or lignin degrading microorganisms.
  • physicochemical methods such as steam explosion treatment, acid treatment and alkali treatment
  • biological methods utilizing lignin degrading enzymes or lignin degrading microorganisms.
  • a pretreatment method for example, physical pulverization, steaming, ozone oxidation, ⁇ -ray irradiation, and the like have been studied.
  • JP-A-2015-080759 discloses a method of separating lignocellulosic nomi-iomas into a liquid component containing lignin and a solid component containing cellulose by treating heat extraction and solid-liquid separation with an ethylene glycol solution in a single stage. Has been.
  • JP 2012-1111849 discloses that wood powder obtained by pulverizing wood chips is degreased, delignified, demicellulose treated and bleached, then treated with cellulase enzymes, and then refined.
  • a method for producing fine fibrous cellulose by performing is disclosed.
  • a delignification treatment a Wise method using sodium chlorite and acetic acid is disclosed as an example.
  • the Journal of the Wood Society of Japan vol. 50, no. 3, pl32-138 (2010) also discloses that delignification treatment is performed using a sodium chlorite solution adjusted to pH 3.8-4.0 by adding acetic acid.
  • JP 2006-001270 A discloses a lignin removal method that maintains the honeycomb structure of wood chips, it is not a treatment that can maintain the shape of the wood chips themselves.
  • the present invention provides a method for removing lignin while maintaining a structure composed of wood, cellulose and hemicellulose with reduced lignin while maintaining the structure as wood, and the method. It aims at providing the manufacturing method of the timber which the lignin reduced by applying, and the said timber.
  • the present invention includes the following. (1) Wood having a lignin content of less than 3% by weight and a cellulose content of 75% by weight or more. (2) The wood according to (1), wherein the cellulose has a viscosity average degree of polymerization DPv of 300 or more. (3) Wood as described in (1) or (2) whose hemicellulose content is 0.01 weight% or more and 15 weight% or less. (4) A first step of immersing a wood raw material in a solution containing an acid and an alcohol under conditions of 140 ° C. or higher and 170 ° C. or lower, and then the wooden raw material is treated with chlorite ions or hypochlorite ions.
  • the wood produced through the second step of immersing in the solution containing the lignin component is reduced.
  • the solution containing the acid and the alcohol is a solution containing sulfuric acid and ethylene glycol or a solution containing sulfuric acid and propylene glycol, according to (8) or (9) Wood manufacturing method.
  • the solution containing an acid and an alcohol has an alcohol concentration of 90 to 99.5% by weight and an acid concentration of 0.05 to 10% by weight.
  • the solution containing the chlorite ion or hypochlorite ion is a sodium chlorite solution or a sodium hypochlorite solution, according to any one of (8) to (12), Wood manufacturing method.
  • the solution containing chlorite ion or hypochlorite ion is a solution having a chlorite ion or hypochlorite ion concentration of 0.01 to 10% by weight (8 ) To (13).
  • FIG. It is an X-ray image which shows the result of having image-analyzed by X-ray CT about the untreated wood raw material used in Example 1, and white wood. It is an image which shows the X-ray fiber figure obtained by X-ray diffraction about the untreated wood raw material used in Example 1, and white wood.
  • FIG. It is a characteristic view which shows the result of having analyzed the component by the infrared absorption spectrum about the untreated wood raw material used in Example 5, the wood raw material after a 1st process, and the white wood obtained after the process. It is the photograph which imaged the white wood obtained after the process used in Example 6.
  • FIG. It is a characteristic view which shows the result of having analyzed the component by the infrared absorption spectrum about the untreated wood raw material used in Example 6, the wood raw material after alkali treatment, the wood raw material after the first step, and the white wood obtained after the treatment. is there.
  • the first embodiment of the present invention is wood having a lignin content of less than 3% by weight and a cellulose content of 75% by weight or more. According to this embodiment, it becomes the wood which has cellulose as a main component and the lignin component is sufficiently reduced.
  • Cellulose is a main component constituting the cell wall and plays an important role in ensuring the strength of the wood.
  • lignin has been considered to play an important role in maintaining the structure of wood by playing a role of bonding between cells or between microfibrils in the cell wall. For this reason, it was very difficult to maintain the structure as wood while reducing lignin.
  • the three-dimensional structure as a wood is maintained despite the lignin component being sufficiently reduced.
  • the amount of lignin is reduced in this way, the detailed mechanism by which the three-dimensional structure is maintained is unknown, but for example, lignin is removed by manufacturing wood by the manufacturing method described later. It is considered that the shape as a three-dimensional structure is maintained by replacing water in the part and maintaining the cellulose structure (cellulose microfibrils, etc.) of the original wood without being destroyed. It is done.
  • the said consideration does not restrict
  • the wood of the present embodiment is white wood when viewed from the outside because the lignin component is sufficiently reduced. Therefore, it can be widely used as a new material.
  • wood refers to a structure (tissue) in which cells are regularly arranged. Wood is clearly distinguished from pulp. It can be observed using an X-ray CT image or the like that the cells are regularly arranged and the tissue is formed as described in Examples below (for example, FIG. 3). As shown in FIG. 3, in wood, adjacent cells are arranged in order without dissociating from each other.
  • X to Y indicating a range includes X and Y, and means “X or more and Y or less”.
  • measurement of operation and physical properties is performed under conditions of room temperature (20 ° C. to 25 ° C.) / Relative humidity 45% RH to 55% RH.
  • the lignin content in the wood is, in order of preference, less than 2% by weight, less than 1% by weight, less than 0.5% by weight, and less than 0.1% by weight.
  • the lower limit is 0% by weight.
  • 0% by weight indicates that the content of each of the following components is below the detection limit when measured by HPLC.
  • the content of cellulose in the wood is 75% by weight or more, and in a preferable order, it is 80% by weight, 85% by weight, 90% by weight, or 95% by weight or more.
  • the cellulose content is 75% by weight or more, the strength in the cellulose fiber direction in the wood structure is improved, and the whiteness is improved.
  • the upper limit of the cellulose content is usually 99.9% by weight or less, preferably 99.5% or less in consideration of the production limit from the viewpoint of maintaining the wood structure.
  • the viscosity average polymerization degree DPv of cellulose contained in the wood is preferably 300 or more. It is preferable that the viscosity average degree of polymerization DPv of cellulose is 300 or more, since it becomes close to the cellulose fiber state of the original tree and the strength of the wood is improved. Usually, when some chemical treatment is performed, the viscosity average degree of polymerization of cellulose is remarkably reduced. For example, according to the production method described later, a significant decrease in the viscosity average degree of polymerization of cellulose is suppressed.
  • the viscosity average polymerization degree DPv of cellulose is more preferably 500 or more, further preferably 800 or more, and particularly preferably 1,000 or more.
  • the upper limit of the viscosity average degree of polymerization DPv of cellulose is preferably closer to the cellulose originally present in the tree, and from this viewpoint, it is usually 10,000 or less, preferably 5,000 or less, More preferably, it is 3,000 or less.
  • the viscosity average degree of polymerization of cellulose can be measured by the following measuring method.
  • ⁇ Measurement method of viscosity average degree of polymerization The Wise method using sodium chlorite and acetic acid is repeated on wood, followed by boiling with 5% aqueous sodium hydroxide to extract cellulose. After dissolving cellulose in copper ethylenediamine, the degree of polymerization is measured from the dropping speed with a Canon-Fenske viscometer. Specifically, it is measured as follows.
  • a 0.5 M copper ethylenediamine solution is prepared, and the viscosity ⁇ 0 is measured using a Canon-Fenske viscometer.
  • a solution in which cellulose is dissolved in a 0.5 M copper ethylenediamine solution (the cellulose concentration is c (g / dL)) is prepared, and the viscosity ⁇ is measured using a Canon-Fenske viscometer.
  • the intrinsic viscosity (sometimes referred to as “ultimate viscosity”) [ ⁇ ] of the cellulose solution is determined by the following formula 1.
  • Intrinsic viscosity [ ⁇ ] ( ⁇ 0 / ⁇ ) / ⁇ c (1 + A ⁇ ⁇ / ⁇ 0 ) ⁇ Equation 1
  • A indicates a unique value depending on the type of solution. In the case of a 0.5 M copper ethylenediamine solution, “A” is 0.28.
  • the viscosity average polymerization degree DPv is obtained by the following formula 2 (Mark-Houwink-Sakurada formula).
  • Intrinsic viscosity [ ⁇ ] K ⁇ DPv ⁇ a Equation 2
  • K and a represent specific values depending on the type of polymer. In the case of cellulose, “K” is 0.57 ⁇ 10 ⁇ 3 and “a” is 1.
  • the content of hemicellulose in the wood is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, further preferably 0.5% by weight or more, and 1% by weight. More preferably, it is more preferably 2% by weight or more.
  • the content of hemicellulose is equal to or more than the above lower limit, the amount becomes sufficient to bind cellulose, and the three-dimensional structure is easily maintained.
  • the upper limit of hemicellulose is not particularly limited, and since the cellulose content is 75% by weight or more, the wood raw material after the first step is 25% by weight or less, and 20% by weight or less. Is preferably 15% by weight or less, more preferably less than 10% by weight, and particularly preferably less than 5% by weight.
  • the hemicellulose content is 0.01 wt% or more and 15 wt% or less.
  • the value measured according to the following measurement conditions is used for the content of each component.
  • the maximum load of the wood is preferably 0.1N or more, more preferably 1N or more, and further preferably 5N or more from the viewpoint of maintaining the crystal structure and ensuring the mechanical strength. Preferably, it is 10N or more and even more preferable.
  • the upper limit of the maximum load of the wood is not particularly limited, but is preferably 1,000 N or less, and more preferably 500 N or less. When the maximum load of the wood is not more than the above upper limit, the wood can easily take a porous structure.
  • the wood of this embodiment has a reduced lignin amount, the appearance is white wood. By making the appearance white, it is possible to obtain a transparent molded product by impregnating the transparent resin, and coloring such as dyeing is also possible.
  • the L * of the wood is preferably 88 or more, more preferably 90 or more, still more preferably 92 or more, and most preferably 93 or more.
  • the a * of the wood is preferably 5 or less, more preferably 3 or less, most preferably 1 or less, further preferably ⁇ 5 or more, more preferably ⁇ 3 or more. And most preferably ⁇ 1 or more.
  • the b * of the wood is preferably 5 or less, more preferably 3 or less, and most preferably 2 or less.
  • whiteness an average value obtained by measuring five points on the wood surface using a color difference meter (SE-6000 manufactured by Nippon Denshoku Industries Co., Ltd.) is adopted.
  • the presence of cellulose and hemicellulose can be qualitatively confirmed by staining cellulose and hemicellulose by PAS staining (polysaccharide staining method).
  • the amount of cellulose and hemicellulose can be quantified based on the dyeing area ratio or the like.
  • the measurement conditions are as follows.
  • Such wood is obtained, for example, by the manufacturing method of the following third embodiment.
  • the manufacturing conditions may be appropriately set depending on the size of the wood, the wood type, and the like, but can be controlled by the immersion time and number of times in the first step, the immersion time and number of times in the second step, and the like. In particular, by increasing the immersion time in the second step and increasing the number of times, it becomes easy to obtain wood with a reduced amount of lignin as described above.
  • a plurality of diffraction spots exist in concentric diffraction images in an X-ray fiber diagram obtained by X-ray diffraction.
  • a diffraction spot can be visually recognized as a black point in the X-ray fiber diagram.
  • the presence of a plurality of diffraction spots indicates that there is no disturbance in the orientation of cellulose microfibrils in the cell wall. Therefore, wood maintains the structure of cellulose microfibrils in the cell wall and is therefore excellent in strength.
  • the plural may be two or more.
  • the number of X-ray diffraction spots is preferably the same as the number of spots observed on the same kind of raw material wood.
  • X-ray fiber diagram is measured as follows. First, a radiation slice is prepared, and a sample wound in a cylindrical shape with the L direction as an axis is set and measured. The measurement conditions are as follows.
  • the full width at half maximum (FWHM) of X-ray diffraction (200 planes) is a viewpoint that the amount of lignin is reduced, the orientation of cellulose is improved, and the strength in the fiber direction is excellent. It is preferably 3 or less, more preferably 2.8 or less, and even more preferably 2.6 or less. Moreover, it is preferable that it is 1 or more from a viewpoint that a transparent molding can be obtained by impregnating a transparent resin, and coloring, such as dyeing
  • FWHM full width at half maximum
  • the crystal structure of cellulose is measured as follows.
  • X-ray apparatus fully automatic horizontal multi-purpose X-ray diffraction apparatus (manufactured by Rigaku Corporation, SmartLab)
  • X-ray source Cu target
  • the raw material (origin) of wood is not particularly limited, it is preferably wood, and a suitable form is selected from the group consisting of conifers, hardwoods and bamboo.
  • the definition of wood in the present specification is “it refers to a structure (tissue) in which cells are regularly arranged”, and therefore bamboo is also included in this specification as a raw material for wood. For this reason, in this specification, bamboo is included in wood.
  • the raw material for wood is preferably cedar, larch, or cypress.
  • the raw material for wood is preferably beech, balsa or elm, and is preferably either beech or elm.
  • bamboo examples include mushrooms, mosouchiku (Moso bamboo), and bees.
  • the raw material is cedar, larch, cypress, beech, elm, balsa or bamboo, and more preferably cedar, larch, cypress, beech, elm or bamboo.
  • This wood is produced through the second step of immersing in a solution containing hypochlorite ions and has a reduced lignin component.
  • the wood according to the second embodiment includes a first step of immersing a wooden raw material in a solution containing an acid and an alcohol under a condition of 140 ° C. or higher and 170 ° C. or lower, and then converting the wooden raw material into chlorite ions or It is produced through a second step of immersing in a solution containing hypochlorite ions. That is, the present invention includes a first step of immersing a wooden raw material in a solution containing an acid and an alcohol under a condition of 140 ° C. or higher and 170 ° C. or lower, and then converting the wooden raw material into chlorite ions or hypochlorite.
  • a form of a method for producing wood having a reduced lignin component comprising a second step of immersing in a solution containing acid ions.
  • the lignin component contained in the wood raw material can be reduced while maintaining the structure composed of cellulose and hemicellulose. Therefore, the wood produced by the method has the characteristics that the structure made of the cellulose and the hemicellulose inherent in the wood raw material is maintained and the lignin component is reduced.
  • the reduced lignin component means that the lignin component in the wood is preferably less than 3% by weight, less than 2% by weight, less than 1% by weight, less than 0.5% by weight, and less than 0.1% by weight. .
  • the wood raw material is a material having a predetermined shape using wood as a raw material.
  • the tree used as a raw material is not particularly limited, it is preferably wood, and a suitable form is selected from the group consisting of softwood, hardwood and bamboo. In particular, conifers are preferred.
  • bamboo examples include mushrooms, mosouchiku (Moso bamboo), and bees.
  • the wood raw material is cedar, larch, cypress, beech, elm, balsa or bamboo, and more preferably cedar, larch, cypress, beech, elm or bamboo.
  • the woody raw material may be produced by performing a predetermined process on the raw material wood. Although it does not specifically limit as a process with respect to wood, Cutting process, grinding process, grinding
  • the wood raw material may be composed of a single member or a plurality of members.
  • a wood raw material composed of a plurality of members can be produced by joining a plurality of members by a general method.
  • Examples of a method for joining a plurality of members include a method using an adhesive, a method using a nail or a screw, a method using a metal fitting, and a method using a joint such as a mortise.
  • the shape of the wood raw material is not particularly limited, and examples thereof include a plate shape, a rod shape, a chip shape, a box shape, and a spherical shape.
  • the shape of the wood raw material it is preferable that the shape of the wood raw material sufficiently penetrates into the solution when immersed in the solution for a predetermined time in the first step and the second step described above. In other words, it is only necessary to adjust the dipping time of the wood raw material in the solution, and it can be understood that the wood raw material may have any shape.
  • the size of the wood raw material is not particularly limited, but it can be a size that allows the solution to sufficiently penetrate into the solution when immersed in the solution in the first step and the second step described above. From this point of view, it can be seen that the preferred range of the size of the wood raw material varies depending on the immersion time in the solution and the type of wood used as the raw material, particularly the density of the wood. For example, when using cedar and the immersion time in the first step and the second step is 1 hour, the distance from the surface may be 10 cm or less at the position where the distance from the surface is the shortest in the wood raw material. Preferably, it is 5 cm or less, more preferably 3 cm or less, and most preferably 1 cm or less and 0.5 cm or less.
  • the same dimension when the immersion time in the first step and the second step is 1 hour is 5 cm or less. Preferably, it is 2.5 cm or less, more preferably 1.5 cm or less, and most preferably 0.5 cm or less.
  • bamboo is used instead of cedar (coniferous tree)
  • the same dimension when the immersion time in the first step and the second step is 1 hour is preferably 10 cm or less, and 5 cm or less. Is more preferably 3 cm or less, and most preferably 1 cm or less.
  • the wood raw material when it is difficult for the wood raw material to be whitened only by the above process, particularly when the wood raw material is bamboo, it is preferable to perform an alkali treatment before the first step described below. Such pretreatment is preferable because the lignin component can be efficiently removed.
  • the alkali used for preparing the alkaline solution is not particularly limited, and is sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, calcium hydroxide, sodium bicarbonate, potassium bicarbonate, hydroxide.
  • Examples include lithium and ammonia.
  • sodium hydroxide, potassium hydroxide, sodium carbonate, and calcium hydroxide are preferable, sodium hydroxide, sodium carbonate, and calcium hydroxide are more preferable, and sodium hydroxide is particularly preferable.
  • the said alkali may be used individually by 1 type, and may be used together 2 or more types.
  • the solvent for dissolving the alkali is not particularly limited, but is preferably water. That is, the alkaline solution is preferably an aqueous sodium hydroxide solution.
  • the alkali treatment is performed by immersing the wood raw material in the alkali solution.
  • the immersion time can be appropriately set according to the shape and size of the wood raw material, the moisture content of the wood raw material, etc., and is, for example, 10 minutes to 5 hours, and 30 minutes to 2 hours.
  • the immersion temperature is not particularly limited, but is preferably 135 ° C. or lower, and more preferably 115 ° C. or lower.
  • the immersion temperature is preferably 55 ° C. or higher, and more preferably 75 ° C. or higher. If the temperature condition is too high, the wood will peel, and if it is too low, delignification in the subsequent process becomes difficult.
  • the above-described wood raw material is immersed in a solution containing an acid and an alcohol under a condition of 140 ° C. or higher and 170 ° C. or lower (first step).
  • the wood raw material may be dried.
  • a drying step may be unnecessary.
  • the wood raw material is immersed in a solution containing acid and alcohol under conditions of 140 ° C. or higher and 170 ° C. or lower.
  • the condition of 140 ° C. or more and 170 ° C. or less means that the atmospheric temperature in the immersion environment is 140 ° C. or more and 170 ° C. or less.
  • the temperature condition is preferably 140 ° C. or higher, more preferably 145 ° C. or higher, from the viewpoint of efficiently promoting delignification. From the viewpoint of suppressing a decrease in the molecular weight of cellulose, it is preferably 170 ° C. or lower, more preferably 165 ° C. or lower, and even more preferably 160 ° C. or lower.
  • the solution used in the first step is a solution containing an acid and an alcohol.
  • Acids such as a sulfuric acid, hydrochloric acid, nitric acid, and an acetic acid, can be mentioned.
  • sulfuric acid is preferably used because of its low volatility as an acid.
  • the alcohol is not particularly limited, but it is preferable to use, for example, a high-boiling point alcohol because the solvent is likely to remain even when heated.
  • High boiling alcohol means, for example, an alcohol having a boiling point of 150 ° C. or higher, preferably 160 ° C.
  • Examples of the alcohol that can be used in the first step include 1,2-ethanediol (ethylene glycol, boiling point: 197.2 ° C.), diethylene glycol (boiling point: 244.3 ° C.), and triethylene glycol (boiling point: 287.4).
  • Propylene glycol is a material that can be used as a food additive, a material that can be used for food packaging materials, and the like, which is preferable in terms of safety. It is a preferable example that the material remaining for obtaining this wood is a food additive, and it is the most preferable example that all the materials used in the reaction are food additives.
  • the solution containing an acid and an alcohol is a solution containing sulfuric acid and ethylene glycol or a solution containing sulfuric acid and propylene glycol.
  • the suitable form of this invention is a solution in which the solution containing an acid and alcohol contains a sulfuric acid and ethylene glycol.
  • the acid concentration is 0.05% by weight or more, 0.1% by weight or more, and 0.3% by weight in order of preference.
  • the acid concentration is preferably 10% by weight or less and 5% by weight in order of preference. Hereinafter, it is 3 weight% or less.
  • the solution containing an acid and an alcohol has an acid concentration of 0.05 to 10% by weight.
  • the alcohol concentration can be 90 to 99.5% by weight, preferably 95 to 99.5% by weight, and preferably 97 to 99% by weight. More preferred is 98 to 99% by weight.
  • concentration of the alcohol in the solution is within this range, the lignin component of the wood raw material can be sufficiently reduced.
  • the concentration of alcohol in the solution is within this range, the lignin component of the wood raw material can be sufficiently reduced, and a structure composed of cellulose and hemicellulose can be easily maintained.
  • the solution used in the first step is preferably an aqueous solution.
  • aqueous solution means that 100% by weight of the solvent is not limited to water, and a water-soluble organic solvent (eg, alcohol) is used in an amount of 0 to 30% by weight, preferably 0 to 5% by weight. In the present invention, these are treated as aqueous solutions. In the most preferred form, 100% by weight of the solvent is water.
  • the wood raw material is immersed in the above solution and heated under a temperature condition of 140 ° C. or higher and 170 ° C. or lower.
  • the temperature condition is not particularly limited as long as it is within the above range, but it is preferably a temperature lower than the boiling point of the alcohol to be used, more preferably 10 ° C. lower than the boiling point of the alcohol to be used.
  • the temperature is 20 ° C. or more lower than the boiling point of the alcohol used.
  • the immersion time in the first step is not particularly limited, but it is preferable that the solution is sufficiently penetrated into the wood raw material.
  • the immersion time in a 1st process can be suitably set according to the shape and dimension of a wooden raw material, the kind of wood used as the raw material of a wooden raw material, the moisture content of a wooden raw material, etc.
  • the reaction is preferably performed under pressure from the viewpoint of reducing the solvent volatilization amount, and the use of a pressure resistant vessel is also a preferred example.
  • the first step it is preferable to carry out a process of replacing air or water contained in the wood raw material with the solution in a state where the wood raw material is immersed in the solution.
  • the solution easily penetrates into the wood raw material.
  • the said wooden raw material is sealed in the state immersed in the said solution, and the process which deaerates the inside of sealed space is mentioned.
  • air and water contained in the wood raw material can be replaced with the above solution by a process such as microwave irradiation (heating with a microwave oven) or ultrasonic irradiation.
  • the immersion time in the first step can be shortened compared to the case where the treatment is not performed.
  • the wood raw material of 1 cm square made of cedar water content: about 15%
  • the immersion time in the first step can be 30 minutes or more, 45 minutes It is preferable to set it as above, and it is more preferable to set it as 1 hour or more.
  • the immersion time can be appropriately set according to the shape and size of the wood raw material, the type of wood used as the raw material of the wood raw material, and the moisture content of the wood raw material.
  • the first step since the temperature condition is set to 140 to 170 ° C. using a solution containing an acid and an alcohol, the structure composed of cellulose and hemicellulose is destroyed while removing the lignin component contained in the wood raw material. It can be maintained without any problems. Note that the first step may be performed once or a plurality of times.
  • the obtained wood raw material may be washed.
  • water, alcohol, etc. are mentioned as a liquid used for washing
  • a mixture of water and alcohol may be used.
  • the alcohol include methanol and ethanol which are easy to handle in the subsequent steps.
  • the washing may be performed a plurality of times, and the liquid type used in each time may be different.
  • the second step of immersing the wood raw material after the first step in a solution containing chlorite ions or hypochlorite ions is performed.
  • an amount of solution sufficient to immerse the entire wood raw material is prepared according to the shape and dimensions of the wood raw material.
  • the solution used in the second step is a solution containing at least chlorite ions or hypochlorite ions.
  • a solution containing chlorite ions is preferred.
  • the solution containing chlorite ions or hypochlorite ions can be referred to as a chlorite or hypochlorite solution (preferably an aqueous solution).
  • the solution used in the second step contains a weak acid such as acetic acid so that delignification is promoted by generating chlorine dioxide having strong oxidizing power in addition to chlorite ion or hypochlorite ion. It is preferable to do.
  • the weak acid component that can be used in the second step include acetic acid, carbonic acid, and boric acid, and it is most preferable to use acetic acid.
  • the pH of the solution used in the second step is preferably less than 11, more preferably 9 or less, and even more preferably 8 or less.
  • the pH of the solution used in the second step is preferably 1 or more, more preferably 3 or more, and most preferably 4 or more.
  • the concentration of chlorite ions or hypochlorite ions is preferably 0.01 to 10% by weight, more preferably 0.05 to 5% by weight. 1 to 5% by weight is more preferred, 0.5 to 5% by weight is even more preferred, and 0.5 to 2% by weight is particularly preferred.
  • the concentration of chlorite ion or hypochlorite ion in the solution is within this range, the lignin component of the wood raw material can be sufficiently reduced. If the concentration of chlorite ion or hypochlorite ion in the solution is within this range, the lignin component of the wood raw material can be sufficiently reduced, and a structure composed of cellulose and hemicellulose can be easily maintained.
  • concentration of the said chlorite ion or a hypochlorite ion is the said range at the time of the first addition. Moreover, since the reactivity of a chlorite ion or a hypochlorite ion is high and unstable, the said density
  • the concentration of the weak acid can be 0.005 to 2.0% by weight, 0.01 to 1.0% by weight, 0.05% Is preferably 0.8 to 0.8% by weight, more preferably 0.1 to 0.6% by weight, and still more preferably 0.5% by weight.
  • concentration of the weak acid in the solution is within this range, the lignin component of the wood raw material can be sufficiently reduced. If the concentration of the weak acid in the solution is within this range, the lignin component of the wood raw material can be sufficiently reduced, and a structure composed of cellulose and hemicellulose can be easily maintained.
  • the solution used in the second step is preferably an aqueous solution.
  • aqueous solution means that 100% by weight of the solvent is not limited to water, and a water-soluble organic solvent (eg, alcohol) is used in an amount of 0 to 30% by weight, preferably 0 to 5% by weight. In the present invention, these are treated as aqueous solutions. In the most preferred form, 100% by weight of the solvent is water.
  • the wooden raw material after the first step is immersed in the above solution.
  • the acid component and the lignin component used in the first step can be removed.
  • the immersion time in the second step is not particularly limited, but it is preferable that the solution sufficiently penetrates into the wood raw material and removes the remaining lignin component as in the first step. For this reason, the immersion time in the second step is set as appropriate according to the shape and size of the wood raw material, the type of wood used as the raw material of the wood raw material, the moisture content of the wood raw material, and the like, as in the first step. be able to.
  • the second step since the reactivity of chlorite ions or hypochlorite ions in the solution is high and unstable, the concentration of chlorite ions or hypochlorite ions described above can be maintained.
  • chlorite or hypochlorite it is preferable to add chlorite or hypochlorite to the solution when a predetermined time has passed.
  • a solution containing chlorite ions or hypochlorite ions sufficiently permeates into the wood raw material, and the remaining lignin component can be removed.
  • “multiple times” refers to 2 times or more, preferably 4 times or more, more preferably 6 times or more, and particularly preferably 8 times or more.
  • the lignin component remaining in the wood raw material can be removed by performing the second step a plurality of times.
  • the upper limit of the number of repetitions of the second step is not particularly limited, but considering productivity, it is preferably 20 times or less, more preferably 15 times or less, and 10 times or less. It is particularly preferred. In addition, as multiple times, it is also a preferable example including continuous dripping and dropping while controlling the pH in the solution.
  • the immersion time in the second step can be made 5 hours or more by adding hypochlorite every hour, and it is 6 hours or more. Preferably, it is more preferably 7 hours or longer.
  • the upper limit of the immersion time is not particularly limited, but it is preferably 10 hours or less in view of the saturation of the effect and the productivity.
  • the immersion time in the second step is set as appropriate according to the shape and dimensions of the wood raw material, the type of wood used as the raw material for the wood raw material, and the moisture content of the wooden raw material, as in the first step. be able to.
  • the temperature condition in the second step is not particularly limited, but can be, for example, 50 to 90 ° C., preferably 60 to 80 ° C., and more preferably 65 to 75 ° C. By setting the temperature condition of the second step within this range, the lignin component remaining after the first step can be sufficiently removed.
  • the wood remaining in the first step is used. While reliably removing the lignin component contained in the raw material, the structure composed of cellulose and hemicellulose can be maintained without destruction. That is, in the method for producing wood according to the present invention, the lignin component originally contained in the wood raw material can be greatly reduced by passing through the second step.
  • washing may be a mixture of water and alcohol.
  • the alcohol include methanol and ethanol which are easy to handle in the subsequent steps.
  • the wood according to the present invention is 80% by weight or more of the lignin component originally contained in the wood raw material, preferably 90% by weight or more, more preferably 95% by weight or more, still more preferably 98% by weight or more. It can be said that the wood is preferably reduced by 99% by weight or more.
  • the first step and the second step according to the shape and size of the wood raw material, the type of wood used as the raw material of the wood raw material, the moisture content of the wood raw material, and the like.
  • the removal of almost all lignin components contained in the wood raw material means that when the lignin component contained in the wood raw material is measured by a method for quantitatively measuring lignin in the wood, it is below the detection limit. means.
  • the lignin component contained in the wood raw material can be reduced within the above-mentioned range, so that the wood raw material before treatment is whitened.
  • the whitening of the wood raw material means that it approaches white according to the degree of reduction of the lignin component, and means that the higher the reduction ratio of the lignin component, the closer the color to white.
  • the wood manufacturing method of the present invention “white wood” can be manufactured.
  • the lignin component contained in the wood raw material can be reduced as described above, and a structure composed of cellulose and hemicellulose can be maintained.
  • maintaining the structure composed of cellulose and hemicellulose means that the cell wall structure inherent to the wood used as the raw material for the wood raw material is maintained, and as a result, the outer shape of the wood raw material before processing. It means that the shape and dimensions are maintained.
  • Maintaining the external shape and dimensions of the wood raw material before the treatment means that when the dimensions of the wood raw material before and after the treatment are measured, the amount of change is 5% or less, preferably 3% or less, more preferably 2% or less, Preferably it means 1% or less.
  • the lignin component contained in the wood raw material before treatment can be significantly reduced, and the wood shape and dimensions of the wood raw material before treatment can be maintained. Can be manufactured.
  • the wood according to the first embodiment or the wood according to the second embodiment (hereinafter “white wood”) is not particularly limited as a new material that has not been conventionally used, and can be applied to various fields.
  • the preferred form of the present invention is wood that maintains the shape of the wood raw material.
  • white wood can be used as the basis for material development using the optimal frame structure created by the tree. .
  • the survival of a huge body of more than 100 meters is guaranteed for more than 1000 years.
  • This is a hierarchical structure made of woody macromolecules whose trees are precisely controlled.
  • microfibrils are extracted after being processed into a pulp-like structure, so that only microfibrils having no orientation can be obtained regardless of the hierarchical structure that trees have. Absent.
  • a technique for uniaxially orienting microfibrils having no orientation has not been established.
  • white wood maintains this hierarchical structure, microfibrils can be utilized while maintaining the orientation in white wood.
  • cellulose microfibrils derived from white wood are used for car bodies, tires, window glass, displays, battery materials, beakers, diapers, thickeners, food packaging materials, artificial blood vessels, artificial cartilage, food additives, etc. Can be used.
  • white wood can be used as a light and strong structural material.
  • white wood can be used as a building material in place of the conventionally used wood.
  • matrix components such as resin, can also be absorbed with respect to white wood. That is, white wood can be used as a new three-dimensional composite resin material according to the required strength.
  • White wood can be used as a porous material in which micropores are formed.
  • a material in which nano-order micropores are formed is called a mesoporous material (a porous material having a pore diameter of several nanometers to several tens of nanometers), but white wood can be used as a mesoporous material.
  • Examples of the use as a mesoporous material include a gas adsorbent, a heat insulating material, a gas separator, and a microorganism culture medium.
  • the color characteristics of white wood is a characteristic that the refractive index of cellulose and hemicellulose components is different from the refractive index of air contained therein. Therefore, by impregnating, for example, an acrylic resin into white wood, the refractive index of cellulose and the hemicellulose component can be brought close to the internal refractive index, and the material becomes colorless and transparent.
  • a colorless and transparent material in which an acrylic resin is impregnated in white wood can be applied to, for example, a display or a solar cell substrate.
  • white wood swells when immersed in, for example, an aqueous sodium hydroxide solution to become a wood gel material.
  • an aqueous sodium hydroxide solution sodium ions enter the inside of the cellulose crystals, spreading the molecules, partially dissolving in the aqueous sodium hydroxide solution, and washing with water forms a cross-linked structure between the celluloses.
  • Specific treatment conditions include a condition of immersing in an aqueous solution of 8 to 20% sodium hydroxide at room temperature, treating for 12 hours, and then washing with water.
  • the wood gel material using white wood becomes, for example, a functional material having elasticity by gelation, and thus can be applied to a medical gel material such as a wound film material and a food gel.
  • white wood is a low environmental load material that was a biodegradable material. That is, as described above, specific applications in a wide range of fields can be understood by paying attention to various features of white wood, but everything using white wood can be completely decomposed by cellulase. For example, when the mesoporous structure of white wood is used as an adsorbent, it is possible to concentrate the adsorbed substance from the environment, for example, by biodegrading the adsorbent. Further, white wood can be used as, for example, a biodegradable heat insulating material instead of conventional foamed polystyrene.
  • Example 1 a wood raw material (woody raw material) of a rectangular parallelepiped (each side 1 cm) made of cedar (coniferous tree) was prepared.
  • a solution in which ethylene glycol and 50% by weight sulfuric acid were mixed at a ratio of 99: 1 (acid concentration in the solution: 0.5% by weight) was prepared.
  • the wood raw material was immersed in the solution and pumped to replace the air in the wood raw material with the solvent.
  • the wood raw material was transferred to the pressure tube together with the solution and treated at 150 ° C. (atmospheric temperature) for 1 hour (first step).
  • the wood raw material was taken out and washed repeatedly with ethanol. Moreover, the solution which consists of 0.08 ml of acetic acid, 0.4 g of sodium chlorite, and 60 ml of water was prepared. And the wood raw material after ethanol washing was immersed in the said solution.
  • the temperature condition was 70 ° C., and the immersion time was 1 hour (second step).
  • the second step was performed 7 times, that is, after 1 hour of immersion, the step of adding 0.08 ml of acetic acid and 0.4 g of sodium chlorite and further treating for 1 hour was performed 7 times. (Immersion time, 8 hours total).
  • FIG. 1 shows untreated wood raw material in (A), wood raw material after the first step treatment in (B), and white wood obtained in (C).
  • the dimensions of these untreated wood raw materials (A) and white wood (C) were measured as follows (Table 1). From this result, it became clear that white wood maintains the external shape and dimensions of untreated woody raw materials.
  • the viscosity average polymerization degree of the cellulose of the white wood of Example 1 is 1115
  • the full width at half maximum (FWHM) of 200 planes by X-ray diffraction is 2.50 (untreated 3.18)
  • the maximum load is 27N. Met.
  • the whiteness of white wood that was subjected to the same operation as Example 1 was L *: 94.0, a *: ⁇ 0.26, b *: 1.02 (untreated: L *: 80.11, a *: 3.39, b *: 17.7).
  • FIG. 3 shows the result of image analysis of untreated wood raw material and white wood by X-ray CT (microfocus X-ray CT system, inspexIOSMX-100CT, manufactured by Shimadzu Corporation). As shown in FIG. 3, it was found that the white wood produced in this example maintained the tissue and cell structure like the untreated wood raw material.
  • FIG. 4 is an image showing an X-ray fiber diagram obtained by X-ray diffraction of the untreated wood raw material used in Example 1 and white wood.
  • X-ray fiber diagram of FIG. 4 a plurality of diffraction spots are observed on a concentric image. Therefore, it was found that the white wood produced in this example maintained the orientation of the microfibrils in the cell wall, as with the untreated wood raw material.
  • Example 2 white wood was produced in the same manner as in Example 1 except that zelkova (hardwood) was used as a raw material and the conditions of the first step were treated at 150 ° C. for 6 hours.
  • zelkova hardwood
  • Fig. 5 shows the wood raw material before treatment and the obtained white wood. Moreover, it was as follows when the dimension of the untreated wood raw material and white wood of a present Example was measured. From this result, it became clear that white wood maintains the external shape and dimensions of untreated woody raw materials.
  • FIG. 7 shows the result of image analysis of untreated wood raw materials and white wood by X-ray CT. As shown in FIG. 7, it was found that the white wood produced in this example maintained the tissue and cell structure like the untreated wood raw material.
  • Example 3 white wood was produced in the same manner as in Example 1 except that propylene glycol was used instead of ethylene glycol in the first step.
  • Fig. 8 shows the wood raw material before treatment and the obtained white wood.
  • (A) shows an untreated wood raw material
  • (B) shows white wood obtained.
  • the dimensions of these untreated wood raw materials (A) and white wood (B) were measured as follows (Table 4). From this result, it became clear that white wood maintains the external shape and dimensions of untreated woody raw materials.
  • the white wood produced in this example maintains the tissue and cell structure in the same manner as the untreated wood raw material. I found out.
  • Example 4 white wood was produced in the same manner as in Example 1 except that Harunire (hardwood) was used as a raw material.
  • FIG. 10 shows the wood raw material before treatment and the obtained white wood.
  • FIG. 10 shows an untreated wood raw material in (A), a wood raw material after the first step treatment in (B), and white wood obtained in (C).
  • the dimensions of these untreated wood raw materials (A) and white wood (C) were measured as follows (Table 5). From this result, it became clear that white wood maintains the external shape and dimensions of untreated woody raw materials.
  • the white wood produced in this example maintains the tissue and cell structure in the same manner as the untreated wood raw material. I found out.
  • Example 5 white wood was produced in the same manner as in Example 1 except that beech (hardwood) was used as a raw material.
  • FIG. 12 shows the wood raw material before treatment and the obtained white wood.
  • FIG. 12 shows untreated wood raw material in (A), wood raw material after the first step treatment in (B), and white wood obtained in (C).
  • the dimensions of these untreated wood raw materials (A) and white wood (C) were measured as follows (Table 6). Moreover, it was as follows when the dimension of the untreated wood raw material and white wood of a present Example was measured. From this result, it became clear that white wood maintains the external shape and dimensions of untreated woody raw materials.
  • the white wood produced in this example maintains the tissue and cell structure in the same manner as the untreated wood raw material. I found out.
  • Example 6 In this example, it was carried out except that the alkali treatment was performed before the first step under the following conditions, that Moso bamboo was used as a raw material, and the first step was performed at 150 ° C. for 4 hours.
  • White wood was produced as in Example 1.
  • the alkali treatment was performed by immersing the wood raw material in a 1% aqueous sodium hydroxide solution and performing heat treatment at 95 ° C. for 1 hour.
  • the obtained white wood is shown in FIG. Moreover, when the dimension of the untreated wood raw material and white wood of a present Example was measured, the white wood maintained the external shape and dimension of the untreated wood raw material.
  • FIG. 15 the result of having analyzed the component by the infrared absorption spectrum about the raw material of wood before a process and the obtained white wood was shown in FIG. As shown in FIG. 15, no band (1510 cm ⁇ 1 ) attributed to lignin was observed in white wood.
  • S1 to S4 are divided into four sections from the inner side to the epidermis (inner side S1 ⁇ skin side S4).
  • the white wood produced in this example maintains the tissue and cell structure in the same manner as the untreated wood raw material. I found out.
  • the viscosity average polymerization degree of the cellulose of the wood of Example 6 was 1473.
  • Example 7 white wood was produced in the same manner as in Example 1 except that balsa (hardwood) was used as a raw material.
  • White wood whiteness (dimensions 5 cm ⁇ 5 cm ⁇ 0.5 cm) is L *: 93.1, a *: ⁇ 0.28, b *: 1.36 (untreated: L *: 85.56, a * : 2.25, b *: 10.64).
  • the white wood produced in this example maintains the tissue and cell structure in the same manner as the untreated wood raw material. I found out.
  • the lignin content was less than 3% by weight
  • the cellulose content was 75% by weight or more
  • the hemicellulose content was 0.01% by weight or more and 15% by weight or less.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Chemical And Physical Treatments For Wood And The Like (AREA)

Abstract

La présente invention élimine la lignine tout en maintenant la structure constituée de cellulose et d'hémicellulose. Une matière première de bois est immergée dans une solution comprenant un acide et un alcool dans les conditions d'une température de 140 à 170 °C, puis est immergé dans une solution contenant des ions d'acide chloreux ou des ions de l'acide hypochloreux.
PCT/JP2019/007944 2018-02-28 2019-02-28 Bois et procédé de production de bois Ceased WO2019168127A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112847709A (zh) * 2021-01-06 2021-05-28 南京林业大学 稀土-碳量子点荧光透明木材的制备方法及荧光透明木材
CN117162210A (zh) * 2023-09-27 2023-12-05 江汉大学 一种毛细力自密实的透明木材及其制备方法

Citations (3)

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Publication number Priority date Publication date Assignee Title
US4693757A (en) * 1984-12-19 1987-09-15 Modeste Sabate Particular method for treating articles made of cork
JP2004330141A (ja) * 2003-05-09 2004-11-25 Fumio Kadoi 白色化木質チップ及びその製造方法
JP2006001270A (ja) * 2005-02-28 2006-01-05 Kosaka Sangyo Kk リグニン除去木材チップ、該リグニン除去木材チップの製造方法、及び該リグニン除去木材チップを用いた有機物分解補助剤

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4693757A (en) * 1984-12-19 1987-09-15 Modeste Sabate Particular method for treating articles made of cork
JP2004330141A (ja) * 2003-05-09 2004-11-25 Fumio Kadoi 白色化木質チップ及びその製造方法
JP2006001270A (ja) * 2005-02-28 2006-01-05 Kosaka Sangyo Kk リグニン除去木材チップ、該リグニン除去木材チップの製造方法、及び該リグニン除去木材チップを用いた有機物分解補助剤

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112847709A (zh) * 2021-01-06 2021-05-28 南京林业大学 稀土-碳量子点荧光透明木材的制备方法及荧光透明木材
CN117162210A (zh) * 2023-09-27 2023-12-05 江汉大学 一种毛细力自密实的透明木材及其制备方法

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