WO2021039648A1

WO2021039648A1 - Composition

Info

Publication number: WO2021039648A1
Application number: PCT/JP2020/031685
Authority: WO
Inventors: 潤一中村; 浩三田尻; 準仙頭; 和樹古性
Original assignee: 株式会社日本触媒
Priority date: 2019-08-28
Filing date: 2020-08-21
Publication date: 2021-03-04
Also published as: JP2022145972A

Abstract

[Problem] To confer a new function to a wood material wherein the amount of lignin has been reduced, while maintaining the structure as a wood material. [Solution] A composition containing: a wood-based structure body having a lignin content of less than 3% by weight, a cellulose content of 65% by weight or higher, and a hemicellulose content of between 0.01% by weight and 15% by weight inclusive; and at least one component selected from the group consisting of a curing compound, a resin, an inorganic substance, a dye, and a pigment.

Description

Composition

The present invention relates to a composition.

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. In particular, when wood is used from the viewpoint of biorefinery, lignin, which is a constituent of wood, is removed to extract cellulose and hemicellulose. Generally, the treatment for removing lignin is called pretreatment. So far, various pretreatment techniques that destroy cells and wall layers have been reported.

Examples of the pretreatment method for removing lignin include physicochemical methods typified by steam explosion treatment, acid treatment and alkali treatment, and biological methods using lignin-degrading enzymes or lignin-degrading microorganisms. In addition to these, as pretreatment methods, for example, physical pulverization, steaming, ozone oxidation, γ-ray irradiation and the like have been studied.

In addition, high-temperature heat treatment using organic solvents such as acetic acid, ethanol, high-boiling alcohol, and phenol is called sorbolisis, and is known as an effective pretreatment method for removing lignin. Non-Patent Document 1 finds a condition that the weight percentage of lignin becomes a single digit by crushing a kind of wood of bridal wreath and treating it with a mixed solvent of ethanol and sulfuric acid at 195 ° C. for 1 hour. Further, in Non-Patent Document 2, when the tissue of the sample after the pretreatment was observed, it was clarified that the lignin in the intercellular layer (the layer between the cells) was preferentially removed. From the above results, it is concluded that the pretreatment methods described in Non-Patent Document 1 and Non-Patent Document 2 are highly effective in pulping, which removes lignin and at the same time promotes isolation between cells.

On the other hand, Patent Document 1 discloses that a lignin-removed wood chip is produced by immersing a sugi wood chip in a soap-soda ash mixed water and treating it with a hydrogen peroxide solution. Patent Document 2 discloses a method of treating lignocellulosic fleaiomas with an ethylene glycol solution by heat extraction and solid-liquid separation in one step to separate a liquid component containing lignin and a solid component containing cellulose. According to Patent Document 3, wood flour obtained by crushing wood chips is degreased, lignin-treated, dehemicellulose-treated, and bleached, and then treated with a cellulase-based enzyme, and then finely divided. A method for producing fibrous cellulose is disclosed. In particular, as an example of the delignin treatment, the Wise method using sodium chlorite and acetic acid is disclosed. Non-Patent Document 3 also discloses that delignin treatment is performed using a sodium chlorite solution in which acetic acid is added to adjust the pH to 3.8-4.0.

Japanese Unexamined Patent Publication No. 2006-001270 JP-A-2015-080759 Japanese Unexamined Patent Publication No. 2012-1111849

As described above, there have been known methods for removing lignin from a lignocellulose material such as wood by various methods. However, the above-mentioned conventional method is a method for separating lignin from cellulose and hemicellulose, which destroys wood tissues and cells, and cannot maintain the shape before treatment. Although Patent Document 1 discloses a method for removing lignin that maintains the honeycomb structure of the wood chip, it is not a process that can maintain the shape of the wood chip itself.

The lignin component of the wood is sufficiently reduced so that it becomes white wood when viewed from the outside. By adding various functions to such wood, it is expected to develop into new uses.

Therefore, in view of the above-mentioned circumstances, an object of the present invention is to impart a new function to wood having reduced lignin while maintaining the structure as wood.

The present invention comprises a wood-based structure having a lignin content of less than 3% by weight, a cellulose content of 65% by weight or more, and a hemicellulose content of 0.01% by weight or more and 15% by weight or less, and a curable compound, a resin, and the like. A composition comprising at least one selected from the group consisting of inorganic substances (including inorganic compounds, the same shall apply hereinafter), dyes, and pigments.

In addition, another embodiment of the present invention comprises a wood-based structure having a lignin content of less than 3% by weight, a cellulose content of 65% by weight or more, and a viscosity average degree of polymerization DPv of the cellulose of 300 or more, and curing. A composition comprising at least one selected from the group consisting of sex compounds, resins, inorganic substances, dyes, and pigments.

Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments. In the present specification, "X to Y" indicating a range means "X or more and Y or less", and unless otherwise specified, operation and measurement of physical properties are performed at room temperature (20 to 25 ° C.) / relative humidity of 45 to 55% RH. Perform under the conditions of. Further, in the present specification, the expression "(meth) acrylic" means "acrylic and / or methacrylic", and the expression "(meth) acrylate" means "acrylate and / or". Or methacrylate ". Further, when the expression "acid (salt)" is used in the present specification, it means "acid and / or a salt thereof".

One embodiment of the present invention comprises a wood-based structure having a lignin content of less than 3% by weight, a cellulose content of 65% by weight or more, and a hemicellulose content of 0.01% by weight or more and 15% by weight or less, and curability. A composition comprising at least one selected from the group consisting of compounds, resins, inorganic substances, dyes, and pigments.

According to the present invention, it is possible to impart various functions to white wood.

In the present invention, the wood-based structure has a lignin content of less than 3% by weight and a cellulose content of 65% by weight or more. By adopting such a structure, the wood-based structure exhibits a white appearance while maintaining the outer shape and dimensions of the wood. Then, by combining such a wood-based structure with, for example, a resin, it can be applied to fields requiring higher strength such as building materials. Then, by combining with a resin, a new function of improving strength can be imparted.

In addition, the appearance may become transparent by coating the surface of the wood-based structure with resin. Such transparent wood gives new functions in terms of aesthetics and design. By combining a wood-based structure with dyes and pigments, it is possible to obtain wood with a colored appearance, and in this case as well, new functions are imparted in terms of aesthetics and design.

Furthermore, the wood-based structure maintains a structure composed of cellulose and hemicellulose, which are constituents of wood raw materials. Therefore, the wood-based structure is a porous material (mesoporous material) in which nano-order micropores between polysaccharides are formed in addition to micrometer-order pores formed by the cell lumen. Materials with nano-order micropores are called mesoporous materials (porous materials with pore diameters of several nanometers to several tens of nanometers). Examples of applications as mesoporous materials include gas adsorbents, heat insulating materials, gas separators, and microbial media. In addition, an inorganic substance can be supported using such a porous material as a base material. Examples of such inorganic substances include those having a deodorant and antibacterial action, as will be described later. By supporting an inorganic substance having a deodorant or antibacterial action, new functions such as deodorant and antibacterial can be imparted. Then, it is preferable that the composition maintains the porosity even after the inorganic substance or the like is supported. That is, in a preferred embodiment of the present invention, the composition is a porous body. Since the composition is a porous body, the surface area per unit incident area and per unit space volume can be improved, and the effects of various supporting materials can be enhanced. Further, it is preferable that at least one selected from the group consisting of curable compounds, resins, inorganic substances, dyes and pigments is attached to the surface of the porous body. It is possible to improve the strength by adhering curable compounds, resins, and inorganic substances to the surface of the porous body, and by adhering inorganic substances, dyes, and pigments, each function such as catalytic function and designability is imparted. It is possible. Here, the "surface" refers to a surface in contact with external air (exposed to the outside), and in the case of a porous body, not only the surface but also the surface inside the inner hole (vacancy) (the surface (vacancy)). It is a concept that also includes the inner surface).

Furthermore, focusing on the characteristics of the wood-based structure that it is derived from trees and does not have chemical modifications, it can be said that it is a biodegradable material with a low environmental load. That is, anything using a wood-based structure can be completely decomposed by cellulase. For example, when focusing on the mesoporous structure of a wood-based structure and using it as an adsorbent, it is possible to concentrate the adsorbed substance from the environment by biodegrading the adsorbent. In addition, white wood can be used as a biodegradable heat insulating material, for example, in place of conventional Styrofoam. Therefore, when combining such a wood-based structure with a resin for the purpose of improving strength, it is preferable to select a biodegradable material such as polylactic acid because the biodegradability of the entire composition is improved. Become.

The composition preferably retains the three-dimensional shape of the wood-based structure, and the composition can be said to be a molded product.

The composition preferably has a transmittance (also referred to as visible light transmittance) at a wavelength of 500 nm of 30% or more. When the visible light transmittance is in the above range, it can be suitably used for an optical material. The visible light transmittance is more preferably 50% or more, more preferably 60% or more, more preferably 70% or more, more preferably 80% or more, and 88% or more. Is more preferable. Such a composition having a high transmittance can be obtained by using it in combination with a resin (including a cured product of a curable compound) as described later. Further, in order to obtain a composition having a high transmittance, the lower limit of the average refractive index of the composition is preferably 1.43 or more, more preferably 1.45 or more, and preferably 1.47 or more. Even more preferably, it is 1.49 or more, and particularly preferably 1.49 or more. The upper limit of the average refractive index of the composition is preferably less than 1.61, more preferably less than 1.58, and even more preferably less than 1.55. As the refractive index, a value measured at 25 ° C. and a wavelength of 589 nm using an Abbe refractive index meter (DR-M2 manufactured by Atago Co., Ltd.) is used.

In the present specification, the value calculated by the method described in the examples is adopted as the transmittance at a wavelength of 500 nm.

The maximum bending load of the composition is 50 MPa or more, 80 MPa or more, 100 MPa or more, more preferably 150 MPa or more, more preferably 200 MPa or more, and further preferably 300 MPa or more, in the order of preference. More preferably, it is particularly preferably 400 MPa or more, and most preferably 500 MPa or more. When the maximum bending load is 150 MPa or more, sufficient mechanical strength can be obtained. Further, the maximum bending load of the composition is preferably higher than the maximum bending load of the wood-based structure. The upper limit of the maximum bending load is not particularly limited, but is usually 2000 MPa or less. Such a composition having a high maximum bending load can be obtained by subjecting a wood-based structure to a pressure (compression) treatment; impregnating a high-strength material; or the like, as described later. The pressurization (compression) treatment of the wood-based structure includes a curing treatment (for example, heat treatment) in which the wood-based structure is impregnated with a resin composition containing a curable compound described later and then the curable compound is cured. It may be done at the same time. The pressure, time, etc. in the pressurization (compression) treatment are appropriately set according to the type, shape, surface texture, thickness, etc. of the wood-based structure. Considering that the physical characteristics of the wood do not deteriorate, the pressure is preferably 0.01 to 20 MPa, more preferably 0.05 to 10 MPa, even more preferably 0.1 to 5 MPa, and the time is preferably 1 to 2400 minutes. 5 to 1200 minutes is more preferable, and 10 to 300 minutes is even more preferable.

It is preferable that the surface of the composition has a grain of wood. Since the composition has a grain of wood, it is excellent in design. A composition having such a grain can be obtained by utilizing the structures of the early wood portion and the late wood portion of the white wood. The wood grain does not have to be entirely wood grain, and may be partially wood grain. The white wood-based structure has a grain, which can be utilized.

[Wooden structure]
The wood-based structure has a lignin content of less than 3% by weight and a cellulose content of 65% by weight or more. According to such an embodiment, cellulose is the main component and the lignin component is sufficiently reduced. Cellulose is a major component of cell walls and plays an important role in ensuring the strength of wood. On the other hand, lignin plays a role of adhering between cells or between microfibrils in the cell wall, and has been considered to play an important role in maintaining the structure of wood. For this reason, it was very difficult to maintain the structure as wood while reducing lignin. According to the wood-based structure, the three-dimensional structure as wood is maintained even though the lignin component is sufficiently reduced. Although the detailed mechanism by which the three-dimensional structure is maintained despite the reduction in the amount of lignin is unknown, for example, lignin is removed by producing wood by the production method described later. It is considered that the shape as a three-dimensional structure is maintained by replacing the water in the portion and maintaining the cellulose structure (cellulose microfibrils, etc.) of the original wood without being destroyed. Be done. The above discussion does not limit the technical scope of the present invention.

The above-mentioned wood-based structure has a sufficiently reduced lignin component, so that it becomes white wood when visually recognized from the outside. Therefore, it can be widely used as a new material.

Here, the wood-based structure in the present specification is a structure derived from wood. Here, wood refers to a structure (tissue) in which cells are regularly arranged. Wood is clearly distinguished from pulp. It can be observed by using an X-ray CT image or the like that the cells are regularly arranged to form a tissue. In wood, adjacent cells are arranged in order without dissociation from each other.

Further, the wood-based structure means that a plurality of diffraction spots are present in a concentric diffraction image in an X-ray fiber diagram obtained by X-ray diffraction. Such diffraction spots can be visually recognized as black spots in the X-ray fiber diagram. The presence of multiple diffraction spots indicates that the orientation of the cellulose microfibrils within the cell wall is undisturbed. Therefore, the wood-based structure also maintains the structure of cellulosic microfibrils in the cell wall and is therefore superior in strength. Here, the plurality may be two or more. The number of X-ray diffraction spots is preferably the same as the number of spots observed in the same type of raw wood.

The X-ray fiber diagram is measured as follows. First, a radiation section is prepared, and a sample wound in a tubular shape about the L direction is set and measured. The measurement conditions are as follows.

Imaging plate single crystal structure analyzer: R-AXIS RAPID manufactured by Rigaku Corporation
X-ray source: Cu target In addition, in the crystal structure of cellulose, the half-value full width (FWHM) of X-ray diffraction (200 planes) is from the 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 further preferably 2.6 or less. Further, from the viewpoint that a transparent molded product (composition) can be obtained by impregnating with a transparent resin, and coloring such as dyeing becomes possible, it is preferably 1 or more, preferably 1.6 or more. Is preferable, and 2 or more is most preferable. It can be said that the crystal structure of natural cellulose is maintained when the full width at half maximum (FWHM) of the X-ray diffraction (200 planes) of cellulose is in such a range. Therefore, wood has excellent strength.

The crystal structure of cellulose is measured as follows.

X-ray equipment: Fully automatic horizontal multipurpose X-ray diffractometer (SmartLab, manufactured by Rigaku)
X-ray source: Cu The lignin content in the target wood-based structure is less than 2% by weight, less than 1% by weight, less than 0.5% by weight, and less than 0.1% by weight in the preferred order. When the lignin content is in such a range, the whiteness is improved. The lower the lignin content, the more preferable, and the lower limit is 0% by weight. Here, 0% by weight means 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-based structure is 65% by weight or more, and in the preferred order, 75% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, and 95% by weight or more. When the content of cellulose is 65% by weight or more, the strength in the direction of the cellulose fibers 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, considering the production limit from the viewpoint of maintaining the wood structure.

The viscosity average degree of polymerization DPv of cellulose contained in the wood-based structure is preferably 300 or more. That is, in a preferable form, the wood-based structure has a lignin content of less than 3% by weight, a cellulose content of 65% by weight or more, and a cellulose viscosity average degree of polymerization DPv of 300 or more. When the viscosity average degree of polymerization DPv of cellulose is 300 or more, it becomes close to the fibrous state of cellulose possessed by the original tree, and the strength of wood is improved, which is preferable. Usually, when some kind of chemical treatment is performed, the viscosity average degree of polymerization of cellulose is significantly 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 degree of polymerization DPv of cellulose is more preferably 500 or more, further preferably 800 or more, and particularly preferably 1,000 or more. Further, the upper limit of the viscosity average degree of polymerization DPv of cellulose is preferably close to that of cellulose originally present in trees, and from such a viewpoint, it is usually preferably 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 is measured by the following method, and the viscosity average degree of polymerization is used including substances that cannot be removed by treatment. In the case of the composition, the woody structure is extracted by a general method.

The viscosity average degree of polymerization of cellulose can be measured by the following measuring method.

<Measuring method of viscosity average degree of polymerization>
Cellulose is extracted by repeating the Wise method using sodium chlorite and acetic acid on the wood-based structure, and then boiling treatment with a 5% aqueous sodium hydroxide solution. After dissolving cellulose in copper ethylenediamine, the degree of polymerization is measured from the falling rate with a Canon-Fenceke viscometer. Specifically, it is measured as follows.

A 0.5 M copper ethylenediamine solution is prepared and the viscosity η ₀ is measured using a Canon-Fenceke viscometer. Further, a solution in which cellulose is dissolved in a 0.5 M copper ethylenediamine solution (cellulose concentration is c (g / dL)) is prepared, and the viscosity η is measured using a Canon-Fenceke viscometer. The intrinsic viscosity (sometimes referred to as "extreme viscosity") [η] of the cellulose solution is determined by the following formula 1.

Intrinsic viscosity [η] = (η ₀ / η) / {c (1 + A × η / η ₀ )} Equation 1
In Formula 1, "A" represents a unique value depending on the type of solution. For a 0.5 M copper ethylenediamine solution, "A" is 0.28.

Next, the viscosity average degree of polymerization DPv is obtained by the following formula 2 (Mark-Houwink-Sakurada formula).

Intrinsic viscosity [η] = K × DPv × a Equation 2
In Equation 2, "K" and "a" represent unique 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-based structure is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, still more preferably 0.5% by weight or more. It is even more preferably 1% by weight or more, and particularly preferably 2% by weight or more. That is, in a preferred embodiment of the present invention, the wood-based structure has a lignin content of less than 3% by weight, a cellulose content of 65% by weight or more, and a hemicellulose content of 0.01% by weight or more and 15% by weight or less. is there. When the content of hemicellulose is at least the above lower limit, the amount is sufficient to bind the celluloses to each other, and the three-dimensional structure is easily maintained. The upper limit of hemicellulose is not particularly limited, and since the cellulose content is 65% by weight or more, it is 35% by weight or less, preferably 25% by weight or less, and 20% by weight or less. It is more preferably 15% by weight or less, further preferably less than 10% by weight, and particularly preferably less than 5% by weight. In a preferred embodiment, the hemicellulose content is 0.01% by weight or more and 15% by weight or less.

For the content of each component, the value measured according to the following measurement conditions is adopted.

<Measurement conditions>
Samples are treated with 72% sulfuric acid at room temperature for 1 hour. Then, the sulfuric acid is diluted with water to about 3%. Dilute sulfuric acid is autoclaved at 121 ° C. for 1 hour. The obtained sample is separated into solid and liquid fractions with a glass filter. The amount of lignin is determined by weighing the solid. After neutralizing the liquid fraction, sugar analysis is performed by HPLC. The HPLC conditions are as follows.

Equipment: Prominence UFLC (manufactured by Shimadzu Corporation)
Column: Asahipak NH2P-50 4E (4 mm x 250 mm, Lot: 080806, Shodex (registered trademark), manufactured by Showa Denko KK)
Pre-column: Asahipak NH2P-50G 4A / Opti-guard DVB (manufactured by Showa Denko KK)
solvent:
Mobile phase A: 0.3% aqueous solution of phosphoric acid Mobile phase B: 0.3% aqueous solution of acetonitrile with phosphoric acid Reactor temperature: 150 ° C.
Column temperature: 45 ° C
Detection conditions: RF-AXL detector The amount of cellulose is defined as the value obtained by multiplying the amount of glucose (% by weight) measured by the above HPLC by 0.9. The amount of hemicellulose is calculated from the following formula;

The maximum load of the wood-based structure is preferably 0.1 N or more, more preferably 1 N or more, and 5 N or more from the viewpoint of maintaining the crystal structure and ensuring the mechanical strength. More preferably, it is even more preferably 10 N or more. The upper limit of the maximum load of the wood-based structure 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-based structure is not more than the above upper limit, it is easy to adopt a porous structure.

For the maximum load, use the value measured under the following measurement conditions.

Equipment: AandD Fortester MCT-2150
Sample size: 1 cm ³ blocks Direction: Fiber direction (compresses the end surface)
Since the amount of lignin is reduced in the wood-based structure, the appearance is white wood. Since the appearance is white, a transparent molded product (composition) can be obtained by impregnating with a transparent resin, and coloring such as dyeing is also possible. The L * of the wood-based structure is preferably 88 or more, more preferably 90 or more, further preferably 92 or more, and most preferably 93 or more. The a * of wood is preferably 5 or less, more preferably 3 or less, most preferably 1 or less, further preferably -5 or more, and more preferably -3 or more. , 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. For the whiteness, the average value of the values measured at 5 points on the wood surface using a color difference meter (SE-6000 manufactured by Nippon Denshoku Kogyo Co., Ltd.) is adopted.

In addition, cellulose and hemicellulose can be stained by PAS staining (polysaccharide staining method) to qualitatively confirm the presence of cellulose and hemicellulose. It is also possible to quantify the amount of cellulose and hemicellulose by the dyed area ratio or the like. The measurement conditions are as follows.

<Measurement conditions>
The sections are oxidized with an aqueous solution of hydrousic acid and then reacted with a Schiff reagent. After washing with sulfite water, further wash with distilled water. Prepare the slide, observe it, and evaluate it with a color difference meter.

Such a wood-based structure can be obtained, for example, by the following manufacturing method. The production conditions may be appropriately set according to the size of the wood, the type of wood, etc., but can be controlled by the immersion time and the number of times in the first step, the immersion time and the number of times in the second step, and the like. In particular, by lengthening the soaking time in the second step and increasing the number of times, it becomes easy to obtain wood having a reduced amount of lignin as described above.

The raw material (origin, wood) of the wood-based structure is not particularly limited, but is preferably wood, and the preferred form is selected from the group consisting of coniferous trees, hardwoods and bamboo as the raw material of the wood-based structure. .. As described above, the definition of wood in the present specification "refers to a structure (tissue) in which cells are regularly arranged", and therefore, bamboo is also included as wood in the present specification. Therefore, in this specification, the wood includes bamboo.

The coniferous trees are not particularly limited, but are sugi, spruce, karamatsu, black pine, todomatsu, himekomatsu, ichii, ginkgo, cat, kaya, harimomi, iramomi, inumaki, fir, sawara, togasawara, asunaro, hiba, tsuga, kometsuga. , Hinoki, Sawara, Inugaya, Spruce, Yellow Cedar (Beihiba), Lawson Hinoki (Beihi), Douglas Fir (Beimatsu), Sitka Spruce (Baitohi), Radiata Matsu, Eastern Spruce, Eastern White Pine, Western Larch, Western Fur, Western Hemlock, Tamarack and the like can be mentioned. Among them, the raw material for wood is preferably any of sugi, larch, and cypress.

Hardwoods are not particularly limited, but beech, cinnamon, white birch, walnut, poplar, eucalyptus, acacia, asada, oak, itaya maple, katsura, sennoki, chestnut, elm, kiri, hoonoki, willow, sen, ubamegashi, konara, oak. , Aesculus turbinata, willow, oak, oak, oak, oak, oak, oak, balsa, aohada and the like. Among them, the raw material for wood is preferably any of beech, balsa and elm, and preferably any of beech and elm.

Examples of bamboo include Madake, Mosouchiku (Moso bamboo), and Hachiku.

Therefore, in a preferred form of the present invention, the raw material (origin) is sugi, larch, cypress, beech, elm, balsa or bamboo, and more preferably sugi, larch, cypress, beech, elm or bamboo.

The wood-based structure is composed of, for example, a first step of immersing the wood in a solution containing an acid and an alcohol under the conditions of 140 ° C. or higher and 170 ° C. or lower, and then the wood is chlorite ion or hypochlorite. It is produced through a second step of immersing it in a solution containing acid ions. According to such a method, the lignin component contained in the wood can be reduced while maintaining the structure composed of cellulose and hemicellulose. Therefore, the wood-based structure produced by the method has a feature that the structure composed of cellulose and hemicellulose originally possessed by wood is maintained and the lignin component is reduced.

The reduction of the 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 in a preferable order. ..

The wood may be made by subjecting the raw material wood to a predetermined process. The processing on wood is not particularly limited, and examples thereof include cutting processing, grinding processing, polishing processing, plane processing, and bending processing. According to these processes, wood as a raw material can be processed into a desired shape to obtain wood having that shape.

Further, the wood may be composed of a single member or may be composed of a plurality of members. For example, by joining a plurality of members by a general method, a wood composed of the plurality of members can be produced. Examples of the method of joining a plurality of members include a method of using an adhesive, a method of using nails and screws, a method of using metal fittings, and a method of using a mortise and tenon.

The shape of the wood 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 is preferably such that the solution sufficiently permeates the inside when immersed in the solution for a predetermined time in the first step and the second step described above. In other words, it can be understood that the wood may have any shape by adjusting the immersion time of the wood in the solution.

The size of the wood is not particularly limited, but it can be set so that the solution sufficiently penetrates into the inside 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 wood varies depending on the immersion time in the solution and the type of wood used as a raw material, particularly the density of wood. For example, when sugi is used and the immersion time in the first step and the second step is 1 hour, the distance from the surface is preferably 10 cm or less at the position where the distance from the surface is the shortest inside the wood. It is more preferably 5 cm or less, further preferably 3 cm or less, and most preferably 1 cm or less and 0.5 cm or less. From the viewpoint of ease of handling in production, it is preferably 0.05 cm or more, and more preferably 0.1 cm or more. When zelkova, elm, beech, and oak (broad-leaved tree) are used instead of sugi (coniferous tree), the same size is 5 cm or less when the immersion time in the first step and the second step is 1 hour. It is more preferably 2.5 cm or less, further preferably 1.5 cm or less, and most preferably 0.5 cm or less. When bamboo is used instead of sugi (coniferous tree), the same size when the immersion time in the first step and the second step is 1 hour is preferably 10 cm or less, preferably 5 cm or less. More preferably, it is more preferably 3 cm or less, and most preferably 1 cm or less.

In the present embodiment, when it is difficult to whiten the wood only by the above steps, especially when the wood is bamboo, it is preferable to carry out the alkali treatment before the first step below. It is preferable to perform such a pretreatment because the lignin component can be efficiently removed.

In the alkali treatment, the alkali used to prepare the alkaline solution is not particularly limited, and sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, calcium hydroxide, sodium hydrogencarbonate, potassium hydrogencarbonate, and hydroxide. Examples include lithium and ammonia. Of these, 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 above alkalis may be used alone or in combination of two or more.

The solvent for dissolving the alkali is not particularly limited, but water is preferable. That is, the alkaline solution is preferably an aqueous solution of sodium hydroxide.

Alkaline treatment is performed by immersing wood in the above alkaline solution. At this time, the immersion time can be appropriately set according to the shape and size of the wood, the water content of the wood, and the like, 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, more preferably 115 ° C. or lower. The immersion temperature is preferably 55 ° C. or higher, more preferably 75 ° C. or higher. If the temperature condition is too high, the wood will peel, and if it is too low, it will be difficult to remove lignin in the subsequent process.

In the method for producing wood according to the present embodiment, first, the above-mentioned wood is immersed in a solution containing an acid and alcohol under the conditions of 140 ° C. or higher and 170 ° C. or lower (first step). The wood may be dried prior to this step. For example, when wood is produced using a desiccant having a moisture content of about 20% or less, a step of drying may not be necessary, but when wood is produced from a material having a moisture content of more than 20%, the moisture content is 20. It is preferable to dry it so that it becomes% or less.

The wood is immersed in a solution containing acid and alcohol under the conditions of 140 ° C or higher and 170 ° C or lower. Here, the condition of 140 ° C. or higher and 170 ° C. or lower means that the atmospheric temperature in the immersion environment is 140 ° C. or higher and 170 ° C. or lower. The temperature condition is preferably 140 ° C. or higher, more preferably 145 ° C. or higher, from the viewpoint of efficiently advancing delignin. From the viewpoint of suppressing the decrease in the molecular weight of cellulose, the temperature is preferably 170 ° C. or lower, more preferably 165 ° C. or lower, and even more preferably 160 ° C. or lower.

In the first step, the amount of solution sufficient to immerse the entire wood is prepared according to the shape and dimensions of the wood. The solution used in the first step is a solution containing an acid and an alcohol. Here, the acid is not particularly limited, and examples thereof include acids such as sulfuric acid, hydrochloric acid, nitric acid, and acetic acid. Of these, sulfuric acid is preferably used because the acid has low volatility. The alcohol is not particularly limited, but it is preferable to use alcohol having a high boiling point, for example, because the solvent tends to remain even when heated. The high boiling point alcohol means, for example, an alcohol having a boiling point of 150 ° C. or higher, preferably 160 ° C. or higher, more preferably 170 ° C. or higher, and even more preferably 180 ° C. or higher. Examples of alcohols 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 ° C.). ℃), propylene glycol (boiling point: 187.4 ° C), 1,3-butanediol (boiling point: 207.5 ° C), 1,4-butanediol (boiling point: 228 ° C), 2-ethyl-1-hexanol (boiling point: 228 ° C) Boiling point: 184.7 ° C.), benzyl alcohol (boiling point: 205.45 ° C.) and the like can be used. Among them, as the alcohol, it is preferable to use ethylene glycol or propylene glycol, and it is more preferable to use ethylene glycol. Propylene glycol is a material that can be used as a food additive, is a material that can be used as a food packaging material, and is preferable in terms of safety. It is a preferable example that the material remaining to obtain the present wood is a food additive, and it is the most preferable example that all the materials used in the reaction are food additives.

A preferred embodiment of the present invention is a solution containing acid and alcohol, which is a solution containing sulfuric acid and ethylene glycol or a solution containing sulfuric acid and propylene glycol. In a preferred embodiment of the present invention, the solution containing acid and alcohol is a solution containing sulfuric acid and ethylene glycol.

From the viewpoint that the lignin component of wood can be sufficiently reduced in the solution used in the first step, the acid concentration is 0.05% by weight or more, 0.1% by weight or more, and 0.3% by weight or more in the preferred order. , 0.5% by weight or more, and from the viewpoint that the structure composed of cellulose and hemicellulose can be easily maintained and the molecular weight of cellulose can be easily maintained, the acid concentration is 10% by weight or less and 5% by weight or less in the preferred order. 3, 3% by weight or less. In a preferred form, the solution containing the acid and alcohol has an acid concentration of 0.05 to 10% by weight.

Further, in the solution used in the first step, the concentration of alcohol can be 90 to 99.5% by weight, preferably 95 to 99.5% by weight, and 97 to 99% by weight. More preferably, it is more preferably 98 to 99% by weight. When the concentration of alcohol in the solution is in this range, it is easy to sufficiently reduce the lignin component of wood. Further, when the concentration of alcohol in the solution is in this range, the lignin component of wood can be sufficiently reduced, and the structure composed of cellulose and hemicellulose can be easily maintained.

In the first step, the wood is immersed in the above solution and heated under a temperature condition of 140 ° C. or higher and 170 ° C. or lower. By heating in such a temperature range, the solution easily penetrates into the wood. At this time, 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 used, and more preferably a temperature 10 ° C. or more lower than the boiling point of the alcohol used. It is preferable that the temperature is 20 ° C. or higher lower than the boiling point of the alcohol used. The immersion time in the first step is not particularly limited, but is preferably such that the solution sufficiently permeates the inside of the wood. Therefore, the immersion time in the first step can be appropriately set according to the shape and size of the wood, the type of wood used as the raw material of the wood, the water content of the wood, and the like. When a solvent having a boiling point equal to or lower than the heating temperature condition is used, it is preferable to react under pressure from the viewpoint of reducing the amount of solvent volatilized, and it is also a preferable example to use a pressure resistant container.

Further, in the first step, it is preferable to carry out a treatment of substituting the air or water contained in the wood with the solution while the wood is immersed in the solution. By performing such a treatment, the solution easily penetrates into the wood. Examples of the treatment include a treatment in which the wood is immersed in the solution and sealed, and the inside of the closed space is degassed. For example, there is a process in which the wood is immersed in the solution in the container, and the container is stored in the vacuum chamber to reduce the pressure in the vacuum chamber. In addition, the air and water contained in the wood can be replaced with the above solution by treatments such as microwave irradiation (heating with a microwave oven) and ultrasonic irradiation.

When the treatment of replacing the air contained in the wood with the solution is carried out, the immersion time in the first step can be shortened as compared with the case where the treatment is not carried out. For example, in the case of a 1 cm square rectangular parallelepiped wood made of sugi (moisture content: about 15%), when the treatment is carried out, the immersion time in the first step can be 30 minutes or more, and 45 minutes or more. It is preferably 1 hour or more, and more preferably 1 hour or more. According to this example, the immersion time can be appropriately set according to the shape and size of the wood, the type of wood used as the raw material of the wood, and the water content of the wood.

In the first step, since the temperature condition is set to 140 to 170 ° C. using a solution containing acid and alcohol, the structure composed of cellulose and hemicellulose is destroyed while removing the lignin component contained in the wood. Can be maintained without. The first step may be performed once or a plurality of times.

After the first step, the obtained wood may be washed. Here, examples of the liquid used for cleaning include water and alcohol. A mixture of water and alcohol may be used. Examples of the alcohol include methanol, ethanol and the like, 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.

Next, the second step of immersing the wood after the first step in a solution containing chlorite ions or hypochlorite ions is carried out. In the second step, as in the first step, an amount of solution sufficient to immerse the entire wood is prepared according to the shape and dimensions of the wood. The solution used in the second step is a solution containing at least chlorite ion or hypochlorite ion. A solution containing chlorite ions is preferable. The solution containing chlorite ion or hypochlorite ion can be said to be a solution of chlorite or hypochlorite (preferably an aqueous solution). The chlorite is not particularly limited, and examples thereof include sodium chlorite and calcium chlorite. Of these, a sodium chlorite solution is preferable as the solution containing chlorite ions because lignin can be removed more effectively. The hypochlorite is not particularly limited, and examples thereof include sodium hypochlorite and calcium hypochlorite. Among them, the solution containing hypochlorite ion is preferably a sodium hypochlorite solution because lignin can be removed more effectively.

In addition to chlorite ion or hypochlorite ion, the solution used in the second step contains a weak acid such as acetic acid so as to generate chlorine dioxide having a strong oxidizing power to promote delignin. It is preferable to do so. Examples of the weak acid component that can be used in the second step include acetic acid, carbonic acid, boric acid, and the like, but acetic acid is most preferable. The pH of the solution used in the second step is preferably less than 11, more preferably pH 9 or less, and even more preferably pH 8 or less. On the other hand, from the viewpoint of maintaining the wood structure and maintaining the molecular weight of cellulose, 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.

In the solution used in the second step, the concentration of chlorite ion or hypochlorite ion is preferably 0.01 to 10% by weight, more preferably 0.05 to 5% by weight, and 0. 1 to 5% by weight is further preferable, 0.5 to 5% by weight is even more preferable, and 0.5 to 2% by weight is particularly preferable. When the concentration of chlorite ion or hypochlorite ion in the solution is within this range, the lignin component of wood can be sufficiently reduced. Further, when the concentration of chlorite ion or hypochlorite ion in the solution is within this range, the lignin component of wood can be sufficiently reduced, and the structure composed of cellulose and hemicellulose can be easily maintained. The concentration of the chlorite ion or hypochlorite ion is preferably in the range at least at the time of the first addition. Further, since the reactivity of chlorite ion or hypochlorite ion is high and unstable, the above concentration is not always maintained during the reaction.

Further, in the solution used in the second step, the concentration of the weak acid can be 0.005 to 2.0% by weight, 0.01 to 1.0% by weight, and 0.05. It is preferably about 0.8% by weight, more preferably 0.1 to 0.6% by weight, and even more preferably 0.5% by weight. When the concentration of weak acid in the solution is in this range, the lignin component of wood can be sufficiently reduced. Further, when the concentration of the weak acid in the solution is in this range, the lignin component of wood can be sufficiently reduced, and the structure composed of cellulose and hemicellulose can be easily maintained.

The solution used in the second step is preferably an aqueous solution. Being an aqueous solution allows water in the solvent to enter the structure, making it easier to maintain the three-dimensional structure. The term "aqueous solution" as used herein means that 100% by weight of the solvent is not limited to water, and 0 to 30% by weight, preferably 0 to 5% by weight, of a water-soluble organic solvent (for example, alcohol) is used in combination. In the present invention, these may be treated as an aqueous solution. In the most preferred form, 100% by weight of the solvent is water.

In the second step, the wood after the first step is immersed in the above solution. At this time, it is preferable to wash the wood after the first step with ethanol or water. In particular, when the wood after the first step is washed with ethanol, 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 as in the first step, it is preferable that the solution sufficiently permeates the inside of the wood and the remaining lignin component can be removed. Therefore, the immersion time in the second step can be appropriately set according to the shape and size of the wood, the type of wood used as the raw material of the wood, the water content of the wood, and the like, as in the first step. However, in the second step, since the reactivity of chlorite ion or hypochlorite ion in the solution is high and unstable, the above-mentioned concentration of chlorite ion or hypochlorite ion can be maintained. As such, it is preferable to add chlorite or hypochlorite to the solution after a lapse of a predetermined time. Alternatively, it is preferable that the second step is repeated a plurality of times. By repeating the second step a plurality of times, the solution containing the chlorite ion or the hypochlorite ion sufficiently permeates the inside of the wood, and the remaining lignin component can be removed. Here, the plurality of 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. By performing the second step a plurality of times in this way, the lignin component remaining inside the wood can be removed. The upper limit of the number of repetitions of the second step is not particularly limited, but in consideration of productivity, it is preferably 20 times or less, more preferably 15 times or less, and 10 times or less. It is particularly preferable to have. It should be noted that, as a plurality of times, it is also a preferable example to include continuous dropping and dropping while controlling the pH in the solution.

For example, in the case of a 1 cm square rectangular parallelepiped wood made of sugi, the immersion time in the second step can be 5 hours or more by adding hypochlorite every hour, and is 6 hours or more. It is preferably 7 hours or more. The upper limit of the immersion time is not particularly limited, but is preferably 10 hours or less in consideration of the saturation of the effect and the productivity. However, the immersion time in the second step can be appropriately set according to the shape and size of the wood, the type of wood used as the raw material of the wood, and the water content of the wood, as in the first step. ..

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 even after the first step can be sufficiently removed.

In the second step, since a solution containing chlorite ion or hypochlorite ion or a solution containing chlorite ion or hypochlorite ion and weak acid is used, the wood remaining in the first step. While reliably removing the lignin component contained in, it can be maintained without destroying the structure composed of cellulose and hemicellulose. That is, by going through the second step, the lignin component originally contained in the wood can be significantly reduced.

It is preferable to wash the wood obtained in the second step with water, alcohol, or the like. The wash may be a mixture of water and alcohol. Examples of the alcohol include methanol, ethanol and the like, which are easy to handle in the subsequent steps. The cleaning treatment is preferable because it is possible to remove the lignin component and the excess raw material / reaction component of the second step, and it is easy to obtain wood having a maintained structure.

In addition, when drying after washing, it is preferable to freeze-dry.

According to the above production method, 80% by weight or more, preferably 90% by weight or more, more preferably 95% by weight or more, still more preferably 98% by weight or more, and most preferably 99% by weight of the lignin component originally contained in the wood. % Or more can be reduced. In other words, the wood according to the present invention is 80% by weight or more, preferably 90% by weight or more, more preferably 95% by weight or more, still more preferably 98% by weight or more, most preferably 98% by weight or more of the lignin component originally contained in the wood. Can be said to be wood with 99% by weight or more reduced.

In particular, in the above-mentioned manufacturing method, the conditions of the first step and the second step are adjusted according to the shape and size of the wood, the type of wood used as the raw material of the wood, the water content of the wood, and the like. Almost all lignin components contained in can be removed. In addition, removing almost all the lignin components contained in wood means that the lignin components contained in the wood are below the detection limit when the lignin components contained in the wood are measured by the method of quantitatively measuring the lignin in the wood. ..

Further, according to the above manufacturing method, the lignin component contained in the wood raw material can be reduced within the above range, so that the wood raw material before the treatment becomes white. Whitening of wood raw materials means that the color approaches white according to the degree of reduction of the lignin component, and that the higher the reduction rate of the lignin component, the closer to white the color is. For example, when the lignin component of the wood obtained by the method for producing wood according to the present invention is measured and is below the detection limit, the wood becomes white. As described above, according to the method for producing wood according to the present invention, "white wood" can be produced.

Furthermore, according to the above manufacturing method, the lignin component contained in the wood raw material can be reduced as described above, and the structure composed of cellulose and hemicellulose can be maintained. Here, maintaining the structure composed of cellulose and hemicellulose means that the cell wall structure originally possessed by the wood used as the raw material of the wood raw material is maintained, and as a result, the outer shape of the wood raw material before treatment is maintained. It means that the shape and dimensions are maintained. Maintaining the outer shape and dimensions of the wood raw material before treatment means that the amount of change when measuring the dimensions of the wood raw material before and after treatment is 5% or less, preferably 3% or less, more preferably 2% or less, and further. It means that it is preferably 1% or less.

According to the method for producing a wood-based structure as described above, a wood-based structure capable of significantly reducing the lignin component contained in the untreated wood and maintaining the outer shape and dimensions of the untreated wood is manufactured. be able to. Such a wood-based structure is not particularly limited as a new material that has never existed before, and can be applied to various fields.

Focusing on the fact that the tissue and cell structure originally possessed by the raw material tree is maintained as a characteristic of white wood, white wood can be used as the basis for material development using the optimum frame structure created by the tree. .. In a harsh natural environment, it is the hierarchical structure made of woody polymers that are precisely formed and controlled by trees that guarantees the survival of a huge body over 100 m for more than 1000 years.

In the conventional production of microfibrils, since the microfibrils are extracted after being processed into a pulp having a structure-free structure, only microfibrils having no orientation can be obtained regardless of the hierarchical structure of the tree. I can't. In addition, a technique for uniaxially orienting non-orientating microfibrils has not been established. However, since white wood maintains this hierarchical structure, microfibrils can be utilized while maintaining the orientation in white wood.

That is, by compressing the obtained white wood in the tangential direction and the grain direction, it is possible to develop a paper or film in which cellulose microfibrils are oriented. In addition, white wood having various tissue structures can be obtained depending on the type of tree used as a raw material. For this reason, even papers and films made of white wood can take advantage of such characteristics of the tissue structure and can be used as materials according to the purpose. The cellulose microfibrils contained in the obtained white wood can naturally be used for applications in which cellulose microfibrils, cellulose nanofibers, and the like have been conventionally used. For example, white wood-derived cellulose microfibrils are used for car bodies, tires, windowpanes, displays, battery materials, sbeekers, diapers, thickeners, food packaging materials, artificial blood vessels, artificial cartilage, food additives, etc. can do.

In addition, The Murata Science Foundation Annual Report No. As described in 30 2016 page 151-153, a technique for producing a high-dielectric material from silver nanowires and nanopaper made of cellulose fibers is known. Since cellulose microfibrils are oriented as a characteristic of white wood, it is possible to produce a highly dielectric material that maintains the characteristics of uniaxially oriented nanopaper. A conductive material can be produced by stretching silver nanowires around white wood. In this way, white wood can be used as a material for electronic components.

Furthermore, white wood swells when immersed in, for example, an aqueous solution of sodium hydroxide, and becomes a wood gel material. This is because when white wood is immersed in an aqueous solution of sodium hydroxide, sodium ions enter the inside of the cellulose crystals to widen the intermolecular force, partially dissolve in the aqueous solution of sodium hydroxide, and when washed with water, the celluloses form a crosslinked structure. Then, it expresses the physical properties as a gel. Specific treatment conditions include conditions in which the product is immersed in an 8 to 20% aqueous sodium hydroxide solution at room temperature, treated for 12 hours, and then washed with water. Since a wood gel material using white wood becomes a functional material having elasticity by gelation, for example, it can be applied to a medical gel material such as a wound coating material or a food gel.

[surface treatment]
The wood-based structure may be surface-treated. The surface referred to here includes the inner surface of the wood structure. That is, the "surface" refers to a surface in contact with external air (exposed to the outside), and in the case of a porous body, not only the surface but also the surface (inside) inside the inner hole (vacancy). It is a concept that also includes the surface). The surface treatment is not particularly limited, but is a dry treatment such as corona treatment, plasma treatment, ozone treatment, (anhydrous) carboxylic acid, alkoxysilane (silane coupling agent), silazane, silyl, isocyanate, imine, etc. Wet treatment with a substance having a skeleton (functional group) such as oxazoline and epoxy (modification by surface reaction with a wood-based structure) and the like can be mentioned.

By the surface treatment with the above-mentioned carboxylic acid anhydride, one of the carboxyl groups can be bonded to wood, and the other can be bonded to, for example, an epoxy group in a curable compound described later. By adopting such a structure, the wood-based structure and the resin become an integrated structure, the generation of an air layer that lowers the transparency and strength is suppressed, and the transparency and strength are improved.

The carboxylic acid anhydride may be any of succinic anhydride; aromatic ring-type acid anhydride such as phthalic acid anhydride; and alicyclic acid anhydride. It is preferable to use an alicyclic acid anhydride because it is a low-viscosity liquid and easy to handle, and from the viewpoint of heat resistance and mechanical properties of the cured product. Specific examples of such alicyclic acid anhydrides include hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyldihydronadic acid anhydride, 1,2,4,5-cyclopentanetetracarboxylic acid. Dianhydride, 1,2,3,6-tetrahydrophthalic anhydride, methyl-1,2,3,6-tetrahydrophthalic anhydride, nadic acid anhydride, methyl nagic acid anhydride, bicyclo [2,2] , 2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 4- (2,5-dioxotetraxtetra-3-yl) -3-methyl-1,2,5, 6-Tetrahydrophthalic anhydride and the like can be mentioned. By imparting hydrophobicity not only to such carboxylic acid anhydride but also to the surface of the wood-based structure, it is possible to reduce the surface tension of the wood-based structure and improve the affinity between the wood and the resin. .. By improving the affinity between the wood-based structure and the resin, the generation of an air layer that lowers the transparency and strength is suppressed, and the transparency and strength are improved. Examples of the structure capable of imparting hydrophobicity include an alicyclic structure, an aromatic ring structure, and an alkyl group.

The surface treatment method for such an acid anhydride is not particularly limited, and examples thereof include a method in which a wood-based structure is immersed in the acid anhydride and then heat-treated if necessary. The number of immersions is appropriately set, but may be performed a plurality of times. By repeating the dipping a plurality of times, the acid anhydride sufficiently permeates the inside of the wood, and the surface treatment can be uniformly performed. The number of immersions is, for example, 1 to 10, and the immersion time is, for example, 1 to 4800 minutes. The heating temperature is not particularly limited as long as the reaction proceeds, but is usually about 45 to 200 ° C. for 1 to 4800 minutes. It is preferable to immerse in an organic solvent before the acid anhydride treatment.

[resin]
The composition of the present embodiment may contain a resin in addition to the wood-based structure.

As mentioned above, the wood-based structure exhibits a white color. The white color is due to the difference between the refractive index of the cellulose and hemicellulose components and the refractive index of the air contained therein. Therefore, by impregnating the white wood-based structure with the resin, the refractive index of the cellulose and the hemicellulose component can be brought close to each other, and the white wood-based structure becomes colorless and transparent. The composition (molded product) obtained by impregnating white wood with resin can be applied to, for example, a display or a solar cell substrate.

In addition, the strength of the wood-based structure can be improved by combining the wood-based structure with the resin.

The resin may be either a natural resin or a synthetic resin, or a mixture thereof.

Natural resins include proteins such as glue, gelatin, casein and albumin; natural rubbers such as arabic rubber and tragant rubber; glucosides such as saponin; alginic acid, propylene glycol alginate, triethanolamine alginate, ammonium alginate and the like. Examples thereof include alginic acids such as derivatives; cellulose derivatives such as methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, ethyl hydroxy cellulose, and acetyl cellulose; and the like.

Examples of the synthetic resin include curable resins such as heat and light, and thermoplastic resins.

The curable resin includes acrylic resin; phenol resin; xylene / formaldehyde resin, ketone / formaldehyde resin, urea resin, melamine resin, aniline resin and other resins obtained by reaction with formaldehyde; furan resin; alkyd resin; polyester resin; Epoxy resin; benzoguanamine resin; urethane resin; and the like can be mentioned.

Examples of the thermoplastic resin include olefin resins such as polyethylene and polypropylene; polystyrene; polyvinyl acetate; (meth) acrylic resins such as polyacrylate and polymethacrylate; vinyl halide resins such as polyvinyl chloride and polyvinylidene chloride; poly. Acrylonitrile; amide resin such as aliphatic polyamide and aromatic polyamide; polycarbonate; silicone resin; polyester resin such as polyethylene terephthalate and polybutylene terephthalate; ABS resin (acrylonitrile-butadiene-styrene resin), ACS resin (chlorinated polyethylene-acrylonitrile- Vinyl-based graft copolymer resin such as styrene resin), AES resin (acrylonitrile-ethylene-styrene resin); urethane resin; phenylene group-containing resin such as polyphenylene ether, polyphenylene oxide, polyphenylene sulfide; fluororesin; polyether ether ketone, Polyether resins such as polyether ketones and polyether sulfones; polyvinyl ether resins; polyvinyl ketone resins; polyxylylene resins; polysulfone resins; polylactic acid; imide resins such as polyimides, polyamideimides and maleimides; cyanate ester resins; thiophenol resins and the like Examples thereof include copolymers in which monomers constituting these resins are appropriately combined. Further, it may be a resin (vinyl resin) obtained by radical polymerization of a monomer having a vinyl group.

Among the resins, epoxy resin, acrylic resin, cellulose derivative, polylactic acid, imide resin, cyanate ester resin, thiophenol resin and polyester resin are preferable, and epoxy resin, imide resin, cyanate ester resin, thiophenol resin and polyester are preferable. Resins are more preferred, and epoxy resins are even more preferred. As the epoxy resin, an aliphatic epoxy resin and an aromatic epoxy resin are preferable, and among them, an aliphatic cyclic epoxy resin (alicyclic epoxy resin, hydrogenated epoxy resin) and an aromatic epoxy resin are preferable. Among them, alicyclic epoxy resin and hydrogenated epoxy resin are more preferable as the epoxy resin because they are excellent in weather resistance, light resistance and the like, and deterioration with time such as coloring is unlikely to occur. On the other hand, from the viewpoint of mechanical strength, an aromatic epoxy resin is preferable. Here, the epoxy resin means a cured, polymerized or crosslinked epoxy compound. For example, the aliphatic cyclic epoxy resin is a cured, polymerized or crosslinked alicyclic epoxy compound and / or hydrogenated compound described below. Means things. Further, as described above, it is also a preferable form to select a biodegradable resin as the resin for the purpose of improving the biodegradability. The biodegradable resin will be described later.

The content of the resin in the composition is preferably 0.1 to 99% by weight, preferably 10 to 90% by weight, and preferably 20 to 80% by weight. By including the resin in such a range, the desired function can be easily exhibited.

In this specification, a curable resin is obtained by curing a curable compound. As an embodiment of the composition of the present invention, a composition (before curing) containing a curable compound (containing a resin composition) and a wood-based structure is also a suitable form.

The preferable content ratio of the resin composition with respect to 100% by weight of the composition containing the resin composition containing the curable compound and the wood-based structure is 85% by weight from the viewpoint of not impairing the characteristics of the wood-based structure. It is preferably less than or equal to, more preferably 80% by weight or less, and further preferably 70% by weight or less. Similarly, the preferable content ratio of the resin composition with respect to 100% by weight of the composition is preferably 5% by weight or more, and more preferably 10% by weight or more, from the viewpoint of binding the wood-based structure. It is more preferably 20% by weight or more, and particularly preferably 30% by weight or more.

Further, a preferable content ratio of the curable compound with respect to 100% by weight of the composition containing the resin composition containing the curable compound and the wood-based structure is 84 from the viewpoint of not impairing the characteristics of the wood-based structure. It is preferably 0% by weight or less, more preferably 80% by weight or less, and further preferably 70% by weight or less. Similarly, the preferable content ratio of the curable compound with respect to 100% by weight of the composition is preferably 4% by weight or more, more preferably 10% by weight or more, from the viewpoint of binding the wood-based structure. It is more preferably 20% by weight or more, and particularly preferably 30% by weight or more.

By mixing the resin composition containing the curable compound with the wood-based structure and then curing it, a composition in which the curable resin is attached to the surface of the wood-based structure can be obtained. Therefore, as an embodiment of the composition of the present invention, a composition obtained by mixing a resin composition containing a curable compound with a wood-based structure and then curing the composition is also a suitable form. According to this form, the fiber structure of the wood-based structure can improve the strength, and the secondary hardening can be used to impart a shape to the wood composition. The amount of the resin composition when the resin composition containing the curable compound (hereinafter, also simply referred to as the resin composition) is mixed with the wood-based structure is 100% by weight of the total of the resin composition and the wood-based structure. It is preferably 85% by weight or less, more preferably 80% by weight or less, and further preferably 70% by weight or less. From the viewpoint of not impairing the characteristics of the wood-based structure, the amount of the resin composition is preferably 85% by weight or less, preferably 80% by weight, based on 100% by weight of the total of the resin composition and the wood-based structure. It is more preferably 70% by weight or less, and further preferably 70% by weight or less. From the viewpoint of binding the wood-based structure, it is preferably 5% by weight or more, more preferably 10% by weight or more, further preferably 20% by weight or more, and more preferably 30% by weight or more. Especially preferable. Further, in a composition obtained by mixing a resin composition containing a curable compound with a wood-based structure and then curing the composition, the bending strength measured by a bending strength test based on JIS 7171: 2016, JIS 7017: 1999, etc. In the preferred order, 50 MPa or more, 80 MPa or more, 100 MPa or more, 150 MPa or more, 200 MPa or more, 300 MPa or more, 400 MPa or more, 500 MPa or more.

The mixing method of mixing the resin composition with the wood-based structure is not particularly limited, and examples thereof include a method of immersing the wood-based structure in the resin composition. The number of immersions is appropriately set, but may be performed a plurality of times. By repeating the dipping a plurality of times, the resin composition sufficiently permeates the inside of the wood, and the resin can be uniformly coated. In addition, during immersion, it is possible to increase the affinity with the surface of the wood-based structure and facilitate the exchange with air, solvent, etc. existing on the resin surface, so ultrasonic treatment should be performed under reduced pressure. Is preferable.

The heating temperature (curing temperature) when the curing is thermosetting is appropriately set depending on the type of the curable compound and the like, but is preferably 45 to 200 ° C, more preferably 100 to 190 ° C, and further preferably 100 to 100. It is 180 ° C. The heating time (curing time) at the time of curing is not particularly limited, but is preferably 10 to 300 minutes, more preferably 20 to 100 minutes. If the curing temperature is too low and / or the curing time is too short, curing may be insufficient. On the other hand, if the curing temperature is too high and / or the curing time is too long, decomposition of the resin component may occur. The curing conditions depend on various conditions, but can be appropriately adjusted by shortening the curing time when the curing temperature is high and lengthening the curing time when the curing temperature is low.

In one preferred embodiment of the present invention, the resin is a curable resin, and in another preferred embodiment, the curable resin is an epoxy resin and / or an acrylic resin, and the curable resin is an epoxy resin. Can be. Hereinafter, epoxy resin and acrylic resin, which are suitable forms of the curable resin, will be described.

The epoxy resin is a cured product of an epoxy resin composition containing an epoxy compound which is a curable compound. The epoxy resin composition may include an epoxy compound, a curing agent, a curing catalyst and an organic solvent. The epoxy resin composition preferably contains at least an epoxy compound, a curing agent and / or a curing catalyst.

Examples of the epoxy compound include an aliphatic epoxy compound (aliphatic chain epoxy compound, an aliphatic cyclic epoxy compound) and an aromatic epoxy compound.

As the aliphatic chain epoxy compound, an aliphatic glycidyl ether type epoxy compound is preferable, and for example, polyhydroxy compounds (ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (PEG600), propylene glycol, dipropylene glycol) are preferable. , Tripropylene glycol, tetrapropylene glycol, polypropylene glycol (PPG), glycerol, diglycerol, tetraglycerol, polyglycerol, trimethylolpropane and its multimers, pentaerythritol and its multimers, glucose, fructose, lactose, maltose, etc. Those obtained by the condensation reaction of epihalohydrin and (mono / polysaccharide, etc.) are preferably used. Of these, an aliphatic glycidyl ether type epoxy compound having a propylene glycol skeleton, an alkylene skeleton, and an oxyalkylene skeleton in the central skeleton is more preferable.

The aliphatic cyclic epoxy compound is a compound having an aliphatic cyclic epoxy group. Examples of the aliphatic cyclic epoxy compound include a hydrogenated epoxy compound and an aliphatic cyclic epoxy compound other than the hydrogenated epoxy compound (simply referred to as an alicyclic epoxy compound).

The hydrogenated epoxy compound is preferably a hydrogenated product of a fully or partially hydrogenated aromatic epoxy compound, more preferably a hydrogenated product of an aromatic glycidyl ether compound, and even more preferably an aromatic polyfunctional glycidyl ether. It is a hydrogenated compound. Specifically, hydrogenated bisphenol A type epoxy compounds, hydrogenated bisphenol S type epoxy compounds, hydrogenated bisphenol F type epoxy compounds and the like are preferable. More preferably, it is a hydrogenated bisphenol A type epoxy compound and a hydrogenated bisphenol F type epoxy compound. In the case of a partially hydrogenated product, the hydrogenation rate is preferably 50% or more (upper limit 100%), more preferably 80% or more, and even more preferably 90% or more.

Examples of the alicyclic epoxy group include an epoxycyclohexane group (epoxycyclohexane skeleton) and an epoxy group (particularly an oxylan ring) added directly to a cyclic aliphatic hydrocarbon or via a hydrocarbon. As the alicyclic epoxy compound, a compound having an epoxycyclohexane group is particularly preferable. In addition, a polyfunctional alicyclic epoxy compound having two or more alicyclic epoxy groups in the molecule is preferable in that the curing rate can be further increased. Further, a compound having one alicyclic epoxy group in the molecule and having an unsaturated double bond group such as a vinyl group is also preferably used as the alicyclic epoxy compound.

Examples of the epoxy compound having an epoxycyclohexane group include 3,4-epoxycyclohexylmethyl-3', 4'-epoxycyclohexanecarboxylate, epsilon-caprolactone-modified-3,4-epoxycyclohexylmethyl-3', 4'. -Epoxycyclohexanecarboxylate, bis- (3,4-epoxycyclohexyl) adipate and the like are suitable. Examples of the alicyclic epoxy compound other than the epoxy compound having an epoxycyclohexane group include 1,2-epoxy-4- (2-oxylanyl) cyclohexane of 2,2-bis (hydroxymethyl) -1-butanol. Examples thereof include adducts and alicyclic epoxides such as heterocyclic epoxy resins such as triglycidyl isocyanurate.

As the alicyclic epoxy compound, commercially available ones can be used, and examples thereof include celoxide 2021P, celoxide 2081, celoxide 2000, and celoxide 3000 (manufactured by Daicel).

An aromatic epoxy compound is a compound having an aromatic ring and an epoxy group in the molecule. Preferable examples of the aromatic epoxy compound include epoxy compounds having an aromatic ring-conjugated system such as a bisphenol skeleton, a fluorene skeleton, a biphenyl skeleton, a naphthalene ring, and an anthracene ring. Of these, a compound having a bisphenol skeleton and / or a fluorene skeleton is preferable. More preferably, it is a compound having a fluorene skeleton. Further, among the aromatic epoxy compounds, a compound having an epoxy group of glycidyl group is preferable, and a compound having a glycidyl ether group (aromatic glycidyl ether compound) is more preferable. Further, a brominated compound of an aromatic epoxy compound may be used.

Preferable examples of the aromatic epoxy compound include a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, a fluorene epoxy compound, and an aromatic epoxy compound having a bromo substituent. Of these, bisphenol A type epoxy compounds and fluorene epoxy compounds are preferable.

As the epoxy compound, an aliphatic cyclic epoxy compound is preferable, and an alicyclic epoxy compound is more preferable, from the viewpoint of light resistance, weather resistance, etc. of the cured epoxy resin.

Specific examples of the epoxy compound include a polyglycidyl etherified product of a polyhydric alcohol having at least one alicyclic ring, or a cyclohexene oxide or a cyclopentene oxide-containing compound obtained by epoxidizing a cyclohexene or cyclopentene ring-containing compound with an oxidizing agent. Examples include compounds. Specific examples of the epoxy compound include hydrogenated bisphenol A diglycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 3,4-epoxy-1-methylcyclohexyl-3,4-. Epoxy-1-methylhexanecarboxylate, 6-methyl-3,4-epoxycyclohexylmethyl-6-methyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-3-methylcyclohexylmethyl-3,4- Epoxy-3-methylcyclohexanecarboxylate, 3,4-epoxy-5-methylcyclohexylmethyl-3,4-epoxy-5-methylcyclohexanecarboxylate, bis (3,4-epoxycyclohexylmethyl) adipate, 3,4- Epoxy-6-methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), propane-2,2-diyl-bis (3,4-epoxycyclohexane), 2,2-bis (3,4-epoxycyclohexyl) Propane, dicyclopentadiene diepoxyside, ethylenebis (3,4-epoxycyclohexanecarboxylate), dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 1-epoxyethyl-3,4-epoxycyclohexane , 1,2-Epoxy-2-epoxyethylcyclohexane, α-pinenooxide, limonendioxide and the like.

The epoxy resin composition may further contain a compound having another polymerizable group (hereinafter, also referred to as “another polymerizable group-containing compound”) in addition to the above epoxy compound.

The polymerizable group may be a curable functional group, and examples thereof include an oxetan group (oxetan ring), a dioxolane group, a trioxane group, a vinyl group, a vinyl ether group, a styryl group, and the like, and an oxetan group is preferable. is there. Further, the curing property of the polymerizable group is influenced not only by the type of group but also by the organic skeleton to which the group is bonded.

Hereinafter, the oxetane compound as another polymerizable group-containing compound will be specifically described.

An oxetane compound is a compound having an oxetane group (oxetane ring). From the viewpoint of curing rate, the oxetane compound is preferably used in combination with an alicyclic epoxy compound and / or a hydrogenated epoxy compound. Further, from the viewpoint of improving light resistance, it is preferable to use an oxetane compound having no aryl group or aromatic ring. On the other hand, from the viewpoint of improving the strength of the cured product, it is preferable to use a polyfunctional oxetane compound, that is, a compound having two or more oxetane rings in one molecule.

Among the oxetane compounds having no aryl group or aromatic ring, examples of the monofunctional oxetane compound include 3-methyl-3-hydroxymethyloxetane, 3-ethyl-3-hydroxymethyloxetane, and 3-ethyl-3-. (2-Ethylhexyloxymethyl) oxetane, isobutoxymethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyloxyethyl (3-ethyl-3-oxetanylmethyl) ether, isobornyl (3-ethyl-3-3) Oxetanylmethyl) ether, 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) ether, ethyldiethylene glycol (3-ethyl-3-oxetanylmethyl) ether and the like are preferable. Among the oxetane compounds having no aryl group or aromatic ring, examples of the polyfunctional oxetane compound include di [1-ethyl (3-oxetanyl)] methyl ether and 3,7-bis (3-oxetanyl) -5. -Oxa-nonane, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1,3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3) -Ethyl-3-oxetanylmethyl) ether, tricyclodecandyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylpropanthris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis ( 3-Ethyl-3-oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl) -3-oxetanylmethyl) ether, polyethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol hexaxe (3-ethyl-3-oxetanylmethyl) ether, dipentaerythritol pentax (3-ethyl- 3-Oxetanylmethyl) ether, dipentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) ether and the like are preferable. Specific examples of the oxetane compound include ETERNALCOLL (R) EHO, ETERNALCOLL (R) OXBP, ETERNALCOLL (R) OXMA, ETERNALCOLL (R) HBOX, and ETERNALCOLL (R) OXIPA (manufactured by Ube Industries, Ltd.). OXT-101, OXT-121, OXT-211, OXT-221, OXT-212, OXT-610 (all manufactured by Toagosei Corporation) and the like are suitable.

Examples of the curing agent include the alicyclic acid anhydride described in the above surface treatment column. The curing agent is preferably used at a ratio of 0.5 to 1.5 equivalents per 1 equivalent of the epoxy group in the compound having an epoxy group.

Examples of the curing catalyst include aliphatic polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenediamine, diethylaminopropylamine, piperidine, N-aminoethylpiperazin, mensendiamine, and m-xylenediamine; 2- Dimethylaminoalkylphenols such as (dimethylaminomethyl) phenol, bis (dimethylaminoethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol; aromatic amines such as methanephenylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone. Acid anhydrides such as trimetic anhydride, ethylene glycol bis (anhydrotrimeritate), glycerol tris (anhydrotrimeritate), pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride; polyamines in diamine acids Polyaminopolyamide to be reacted; imidazoles such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole; boron trifluoride-amine complex; disyandiamide; aromatic diazonium salt; polysulfides and the like. .. The curing catalyst is preferably 0.01 to 15 parts by weight, more preferably 0.01 to 12 parts by weight, still more preferably 0.05 to 10 parts by weight, and particularly preferably 0, based on 100 parts by weight of the epoxy compound. .1 to 10 parts by weight.

As the organic solvent, various conventionally known solvents can be used.

When the epoxy resin and / or the epoxy compound and / or the compound capable of reacting with the carboxylic acid (for example, the compound having an epoxy group, a hydroxyl group, an amino group, an imino group, or an oxazoline group) is contained. As described above, it is preferable to perform a surface treatment for imparting a carboxyl group to the wood-based structure in advance. Specifically, the surface treatment can be performed by wet-treating an carboxylic acid anhydride or the like.

When the curable compound is an epoxy compound, a preferable content ratio of the resin composition to 100% by weight of the composition containing the curable compound and the wood-based structure impairs the characteristics of the wood-based structure. From the viewpoint that there is no such thing, it is preferably 85% by weight or less, more preferably 80% by weight or less, and further preferably 70% by weight or less. Similarly, the preferable content ratio of the resin composition to 100% by weight of the composition is preferably 5% by weight or more, more preferably 10% by weight or more, from the viewpoint of binding the wood-based structure. , 20% by weight or more, and particularly preferably 30% by weight or more.

When the curable compound is an epoxy compound, the preferable content ratio of the epoxy compound to 100% by weight of the composition containing the curable compound and the wood-based structure does not impair the characteristics of the wood-based structure. From this viewpoint, it is preferably 84% by weight or less, more preferably 80% by weight or less, and even more preferably 70% by weight or less. Similarly, the preferable content ratio of the epoxy compound with respect to 100% by weight of the composition is preferably 4% by weight or more, more preferably 10% by weight or more, from the viewpoint of binding the wood-based structure. It is more preferably 20% by weight or more, and particularly preferably 30% by weight or more.

Examples of the acrylic resin include UV curable acrylic resin and thermosetting acrylic resin. The UV curable acrylic resin is a cured product (including a polymer) of a resin composition containing an acrylate monomer which is a curable compound.

Examples of the acrylate monomer include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, and n-octyl. Acrylate, n-decyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, allyl acrylate, benzyl acrylate, butoxyethyl acrylate, butoxyethylene glycol acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, 2-ethylhexyl acrylate, glycerol acrylate, glycidyl acrylate, 2-Hydroxyethyl acrylate, 2-hydroxypropyl acrylate, isobonyl acrylate, isodexyl acrylate, isooctyl acrylate, lauryl acrylate, 2-metricethyl acrylate, methoxyethylene glycol acrylate, phenoxyethyl acrylate, stearyl acrylate, ethylene glycol di Acrylate, diethylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexadiol diacrylate, 1,3-propanediol acrylate, 1,4-cyclohexanediol diacrylate, 2,2-Dimethylol propanediacrylate, glycerol diacrylate, tripropylene glycol diacrylate, glycerol triacrylate, trimethylol propane triacrylate, ethylene oxide modified trimethylol propane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethylene Oxide-modified pentaerythritol triacrylate, ethylene oxide-modified pentaerythritol tetraacrylate, propionoxide-modified pentaerythritol triacrylate, propionoxide-modified pentaerythritol tetraacrylate, triethylene glycol diacrylate, polyoxypropyltrimethylol propantriacrylate, butylene glycol diacrylate , 1,2,4-butanediol triacrylate, 2,2,4-trimethyl-1,3-pentadio Ludiacrylate, diallyl fumarate, 1,10-decanediol dimethyl acrylate, pentaerythritol hexaacrylate, and the above acrylate replaced with methacrylate, γ-methacryloxypropyltrimethoxysilane, 1-vinyl-2-pyrrolidone. And so on. The above acrylate monomer can be used as one or a mixture of two or more kinds, or as a mixture with other compounds.

The above resin composition usually contains a photopolymerization initiator.

Examples of the photopolymerization initiator include benzophenone, methyl o-benzoylbenzoate, 4,4-bis (dimethylamine) benzophenone, 4,4-bis (diethylamine) benzophenone, α-amino-acetophenone, and 4,4-dichloro. Benzophenone, 4-benzoyl-4-methyldiphenylketone, dibenzylketone, fluorenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, p- tert-Butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, diethylthioxanthone, benzyldimethylketal, benzylmethoxyethyl acetal, benzoinmethyl ether, benzoin butyl ether, anthraquinone, 2-tert-butylanthraquinone , 2-Amil anthraquinone, β-chloroanthraquinone, antron, benzanthron, dibenzsberon, methylene antron, 4-azidobenzylacetophenone, 2,6-bis (p-azidobenzylidene) cyclohexane, 2,6-bis (p-azidobenziliden) ) -4-Methylcyclohexanone, 2-phenyl-1,2-butadione-2- (o-methoxycarbonyl) oxime, 1-phenyl-propanedione-2- (o-ethoxycarbonyl) oxime, 1,3-diphenyl- Propantrione-2- (o-ethoxycarbonyl) oxime, 1-phenyl-3-ethoxy-propanthrion-2- (o-benzoyl) oxime, Michler ketone, 2-methyl [4- (methylthio) phenyl] -2-monophorino -1-Propane, 2-benzyl-2-dimethylamino-1- (4-monophorinophenyl) -butanone-1, naphthalenesulfonyl chloride, quinolinesulfonyl chloride, n-phenylthioacridone, 4,4-azobis Photoreducing dyes such as isobutyronitrile, diphenyldisulfide, benzthiazoledisulfide, triphenylphosphine, camphorquinone, carbon tetrabromide, tribromophenylsulfone, benzoin peroxide, eosin, methylene blue and ascorbic acid, triethanolamine Examples thereof include a combination of reducing agents such as the above, and these photopolymerization initiators can be used alone or in combination of two or more. The photopolymerization initiator is usually preferably 0.01 to 15 parts by weight, more preferably 0.01 to 12 parts by weight, still more preferably 0.05 to 10 parts by weight, particularly preferably 0.01 to 15 parts by weight, based on 100 parts by weight of the acrylate monomer. Is 0.1 to 10 parts by weight.

When the curable compound is an acrylate monomer, the preferable content ratio of the resin composition to 100% by weight of the composition containing the curable compound and the wood-based structure does not impair the characteristics of the wood-based structure. From the viewpoint, it is preferably 85% by weight or less, more preferably 80% by weight or less, and further preferably 70% by weight or less. Similarly, the preferable content ratio of the resin composition to 100% by weight of the composition is preferably 5% by weight or more, more preferably 10% by weight or more, from the viewpoint of binding the wood-based structure. , 20% by weight or more, and particularly preferably 30% by weight or more.

When the curable compound is an acrylate monomer, the preferable content ratio of the acrylate monomer to 100% by weight of the composition containing the curable compound and the wood-based structure does not impair the characteristics of the wood-based structure. From the viewpoint, it is preferably 84% by weight or less, more preferably 80% by weight or less, and further preferably 70% by weight or less. Similarly, the preferable content ratio of the acrylate monomer to 100% by weight of the composition is preferably 4% by weight or more, more preferably 10% by weight or more, from the viewpoint of binding the wood-based structure. It is more preferably 20% by weight or more, and particularly preferably 30% by weight or more.

[Biodegradable resin]
Since the wood-based structure is a biodegradable material, selecting a biodegradable resin as the resin improves the strength as well as the biodegradability. That is, in a preferred embodiment of the present invention, the resin is a biodegradable resin.

Examples of the biodegradable resin include polylactic acid, polyglycolic acid, polylactic acid-polyglycolic acid copolymer, polycaprolactone, polylactic acid-polycaprolactone copolymer, polyorthoester, polyphosphazene, polyphosphate ester, and poly. Hydrohydroxybutyrate, polyappleic acid, polybutylene succinate, polybutylene adipate terephthalate, modified polyethylene terephthalate, polyvinyl alcohol, polyhydroxyalkanoate, bacterial cellulose, chitosan / cellulose / starch, cellulose acetate, esterified starch, polyα- Examples include amino acids, collagen, gelatin, starch, and mixtures thereof. Among them, the biodegradable resin is preferably polylactic acid or starch.

The biodegradable resin is preferably contained in the composition in an amount of 30% by weight or more, more preferably 50% by weight or more, and more preferably 90% by weight or more. By containing 30% by weight or more of the biodegradable resin in the composition, the biodegradability can be enhanced and the environmental harmfulness can be reduced. The biodegradable resin is preferably 99% by weight or less in the composition. By reducing the amount of biodegradable resin, it becomes a material with excellent mechanical strength and stability.

When the wood-based structure is impregnated with the wet surface treatment or resin or curable compound, it is preferable not to dry the wood-based structure (white wood) treated in the second step after obtaining it. When dried, it is difficult to remove the air existing at the interface between the wood-based structure and the surface treatment agent, resin, and curable compound, which leads to deterioration of transparency and strength. Therefore, it is preferable to impregnate the surface treatment agent, resin, and curable compound with a highly compatible solvent so that the white wood after cleaning is not dried and becomes incompatible.

[Inorganic substances]
The composition of the present embodiment may contain an inorganic substance in addition to the wood-based structure. In addition, the inorganic substance can be an inorganic compound.

The inorganic substance is not particularly limited, but is preferably a metal and its ions, oxides, salts, chlorides or a mixture thereof. Here, the metal refers to a metal excluding non-metals of groups 1 to 16. The metal species may be a single element or a combination of a plurality of elements.

The inorganic substance is added for the purpose of imparting a function to the composition. The above-mentioned function is preferably a function of keeping a space in which the composition is installed in a clean state, and specific examples thereof include a deodorant and / or antibacterial function. The deodorant function shown here is to chemically decompose the odorous substance on the inorganic substance, and the antibacterial function is to suppress the activity of microorganisms and not increase the number of bacteria in the initial state. is there.

Substances with deodorizing function include titanium oxide, zirconium oxide, iron oxide, aluminum sulfate, copper sulfate, zinc carbonate, zinc sulfate, zinc chloride, nickel, tin, lead, cobalt, platinum, palladium, silver, molybdenum, etc. Various inorganic substances including ruthenium, strontium and the like can be mentioned. Examples of the substance having an antibacterial function include metals such as silver, zinc and copper, and titanium oxide.

Among them, the inorganic substances are preferably silver, copper and titanium oxide.

Preferable forms of existence of inorganic substances are ionic, atomic, and particulate.

Above all, it is preferable that the inorganic substance exists in the form of particles on the surface of the wood structure. The average particle size at this time is about 0.01 to 100 μm, preferably 1 to 100 μm. The average particle size is an average value (number basis) calculated by measuring the particle size of 1000 particles by an observation means such as TEM and SEM (preferably SEM). The particle diameter is represented by the diameter assuming a circle equal to the projected area (diameter equivalent to the projected area circle).

Further, when the inorganic substance is in the form of particles, a form existing in a nano-sized size is also preferable. In this case, the average particle size of the inorganic substance is preferably 100 nm or less, more preferably 20 nm or less, further preferably 10 nm or less, preferably 1 nm or more, more preferably 2 nm or more, still more preferably 5 nm or more.

The content of the inorganic substance in the composition is 10% by weight to 5% by weight. If the content of the inorganic substance is less than 10 wt ppm, the expected function (for example, deodorant function) may not be obtained, and if it exceeds 5 wt%, the surface gloss and design of the composition are impaired. There is a risk.

The method for supporting the inorganic substance on the wood-based structure is not particularly limited, but for example, a liquid phase reduction method, an evaporation dry solid method, a colloid adsorption method, a spray pyrolysis method, and a reverse micelle (microemulsion method). Etc. can be used. Further, the carboxylic acid on the surface of the wood-based structure may be converted into Na carboxylate, and metal ions such as Cu ion and Ag ion may be supported by utilizing the difference in ionization tendency. The simplest method is to apply a commercially available coating agent containing an inorganic substance to the wood-based structure. The coating agent may be applied directly to the wood-based structure, or may be applied to a composition in which the wood-based structure is combined with a resin to improve the strength.

[Pigment]
The composition of the present embodiment may contain a pigment in addition to the wood-based structure.

The wood structure contains a pigment, preferably the pigment adheres to the surface of the wood structure, so that it is possible to add color to the wood structure.

The pigment is not particularly limited, and may be an organic pigment, an inorganic pigment, or a mixture thereof.

Examples of inorganic pigments include alumina, titanium dioxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, silica ash stone, silica soil, and various inorganic oxide pigments. , Chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silica fine powder, silicon carbide, silicon nitride, boron carbide, tungsten carbide, titanium carbide, cerium oxide, Examples include carbon black. Further, such an inorganic pigment may be treated with a known hydrophobizing agent such as a titanium coupling agent, a silane coupling agent or a higher fatty acid metal salt.

Inorganic pigments are inorganic substances, but inorganic substances having a function as pigments are referred to as "pigments".

Examples of organic pigments include yellow pigments such as Nabres Yellow, Naftor Yellow S, Hanser Yellow G, Hanzer Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Kinolin Yellow Lake, Permanent Yellow NCG, and Tartradin Lake, and Kiribden. Orange pigments such as orange, permanent orange RK, benzine orange G, indanthrone brilliant orange GK, permanent red 4R, resole red, pyrazolone red 4R, watching red calcium salt, lake red D, brilliant carmine 6B, eomin lake, rhodamin lake B , Red pigments such as buzalin lake, brilliant carmine B, purple pigments such as fast violet B, methyl violet lake, alkaline blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partial chloride, fast sky blue, indanthrone blue Examples thereof include blue pigments such as indanthrone blue BC, pigment green B, malakite green lake, and green pigments such as final yellow green G.

These organic pigments may also be treated pigments having improved dispersibility by using a dispersion aid or the like.

The content of the pigment in the composition is appropriately set in order to exert a desired function, but is usually 0.0001 to 10% by weight.

[dye]
The composition of the present embodiment may contain a dye in addition to the wood-based structure.

The wood structure contains a dye, preferably the dye adheres to the surface of the wood structure, so that it is possible to add color to the wood structure.

Examples of the dye include azine dyes, anthraquinone dyes, perinone dyes, rhodamine dyes, and the like. I. Solvent Black 5, C.I. I. Solvent Black 7, Spirit Black SB, Toluidine Blue, C.I. I. Solvent Blue 11, C.I. I. Solvent Blue 12, C.I. I. Solvent Blue 35, C.I. I. Solvent Blue 59, C.I. I. Solvent Blue 74, 1-aminoanthraquinone, 2-aminoanthraquinone, hydroxyethylaminoanthraquinone, C.I. I. Examples thereof include Solvent Violet 47, Solvent Orange 60, Solvent Orange 78, Solvent Orange 90, Solvent Violet 29, Solvent Red 135, Solvent Red 162, Solvent Red 179, Rhodamine-B base and the like.

The content of the dye in the composition is appropriately set in order to exert the desired function, but is usually 0.0001 to 10% by weight.

[Biological material]
The composition of the present embodiment preferably contains 30% by weight or more of a biological material. By containing 30% by weight or more of bio-derived materials, it is possible to reduce the use of petroleum-derived raw materials that cause global warming, and it is possible to reduce greenhouse gases as a measure against global warming. The biological material referred to here refers to a material produced from biomass (renewable biological organic resource excluding fossil resources).

Bio-derived materials include polylactic acid, polyhydroxyalkanoate, biopolyolefin, nylon 11, nylon 1010, biopolytrimethylene terephthalate, biopolyethylene terephthalate, biopolyurethane, biounsaturated polyester, biopolyester, nylon 610, and cellulose acetate. Examples thereof include (CA), biopolybutylene succinate, compounds made from bioethanol, and natural polymers such as gelatin and starch.

[Additive]
The above compositions include antioxidants, UV absorbers, light stabilizers, plasticizers, non-reactive compounds, chain transfer agents, thermal polymerization initiators, anaerobic polymerization initiators, polymerization inhibitors, inorganic fillers, organic fillers. , Adhesion improver such as coupling agent, heat stabilizer, antibacterial / antifungal agent, flame retardant, matting agent, defoaming agent, leveling agent, wetting / dispersing agent, sedimentation inhibitor, thickener / sagging prevention It may contain an agent, a color-coding inhibitor, an emulsifier, an anti-slip / scratch inhibitor, an anti-skin agent, a desiccant, an antifouling agent, an antistatic agent, a conductive agent (electrostatic aid), a solvent and the like.

[Use]
Since the composition of the present embodiment utilizes a wood-based structure, it has high strength even though it is lightweight. Further, the appearance can be processed into a desired appearance such as white, colorless transparent, colored transparent, and colored. Therefore, the composition of the present embodiment can be used for structural materials, interior materials, exterior materials, automobiles, railways, ship structural materials, interior materials, exterior materials, furniture, and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the technical scope of the present invention is not limited to the following Examples. In the examples, the indication of "parts" or "%" may be used, but unless otherwise specified, it indicates "parts by weight" or "% by weight". Unless otherwise specified, each operation is performed at room temperature (25 ° C.).

[Synthesis Example 1]
In this embodiment, five rectangular parallelepiped (50 mm × 10 mm × 2 mm) rotary lace-cut wood raw materials (wood) made of sugi (conifer) were prepared. First, a solution was prepared in which ethylene glycol and 50% by weight sulfuric acid were mixed at a weight ratio of 99: 1 (acid concentration in the solution was 0.5% by weight). The wood raw material was immersed in 120 ml of the solution in a closed container and pumped to replace the air in the wood raw material with a solvent. Next, the wood raw material was treated together with the solution at 150 ° C. (atmospheric temperature) for 1 hour (first step).

After the treatment, the wood raw materials were taken out and washed repeatedly with ethanol. In addition, a solution consisting of 0.16 ml of acetic acid, 0.8 g of sodium chlorate and 120 ml of water was prepared. Then, the wood raw material after washing with ethanol was immersed in the solution. The temperature condition was 70 ° C. and the immersion time was 1 hour (second step). In this example, the second step was carried out eight times, that is, after the soaking time of 1 hour had elapsed, 0.16 ml of acetic acid and 0.8 g of sodium chlorate were added, and the step of further treating for 1 hour was carried out 7 times (). Soaking time, total 8 hours).

Then, by taking out the completely bleached wood and washing it with water, it is possible to obtain a white wood (woody structure) in which the lignin component is removed and the structure composed of cellulose and hemicellulose is maintained. It was. The dimensions of untreated wood and white wood (wooden structure) were measured and found as follows (Table 1). From this result, it was clarified that the white wood (wooden structure) maintains the outer shape and dimensions of the untreated wood.

In addition, the amount of lignin in wood was 14%, whereas the amount of lignin in white wood (wooden structure) was less than 0.1% by weight. The cellulose content of wood is 38% by weight, which is obtained by multiplying the glucose content (% by weight) by 0.9, and the cellulose content of white wood (woody structure) is obtained by multiplying the glucose content (% by weight) by 0.9. It was only 87% by weight. The amount of hemicellulose in the wood raw material was 17% by weight from the contents (% by weight) of xylose, arabinose, mannose, and galactose, while the amount of hemicellulose in white wood (woody structure) was 2% by weight.

The viscosity average degree of polymerization of cellulose in the white wood (woody structure) of Synthesis Example 1 is 1100, and the full width at half maximum (FWHM) of 200 faces by X-ray diffraction is 2.50 (3.18 for untreated). ), The maximum load was 27N. The whiteness of white wood (woody structure) is L *: 94.0, a *: -0.3, b *: 1.0 (untreated: L *: 80.1, a *: 3.4. , B *: 17.7).

Furthermore, in the wood-based structure, in the X-ray fiber diagram obtained by X-ray diffraction, a plurality of diffraction spots were present in the concentric diffraction images.

[Synthesis Example 2]
Five rotary lace-cut wood raw materials (wood) of a rectangular parallelepiped (50 mm x 10 mm x 1 mm) made of sugi (conifer) were prepared. First, a solution was prepared in which ethylene glycol and 50% by weight sulfuric acid were mixed at a weight ratio of 99: 1 (acid concentration in the solution was 0.5% by weight). The wood raw material was immersed in 120 ml of the solution in a closed container and pumped to replace the air in the wood raw material with a solvent. Next, the wood raw material was treated together with the solution at 145 ° C. (atmospheric temperature) for 1 hour (first step).

After the treatment, the wood raw materials were taken out and washed repeatedly with ethanol. In addition, a solution consisting of 0.16 ml of acetic acid, 0.8 g of sodium chlorate and 120 ml of water was prepared. Then, the wood raw material after washing with ethanol was immersed in the solution. The temperature condition was 70 ° C. and the immersion time was 1 hour (second step). In this example, the second step was carried out three times, that is, after the soaking time of 1 hour had elapsed, 0.16 ml of acetic acid and 0.8 g of sodium chlorate were added, and the step of further treating for 1 hour was carried out twice (). Soaking time, total 3 hours).

Then, by taking out the completely bleached wood and washing it with water, it is possible to obtain a white wood (woody structure) in which the lignin component is removed and the structure composed of cellulose and hemicellulose is maintained. , The white wood (wooden structure) of Synthesis Example 2 was prepared. When the dimensions of the untreated wood and the white wood (wooden structure) were measured, the white wood (wooden structure) maintained the outer shape and dimensions of the untreated wood. The amount of lignin in white wood (woody structure) was less than 0.1% by weight, the amount of cellulose was 87% by weight, the amount of hemicellulose was 2% by weight, and the average degree of polymerization of cellulose was 1100. Further, in the wood-based structure, in the X-ray fiber diagram obtained by X-ray diffraction, a plurality of diffraction spots were present in the concentric diffraction images.

[Example 1]
After impregnating one white wood (50 mm × 10 mm × 2 mm) obtained in Synthesis Example 1 with water, the solvent was lightly wiped off. Then, the sample was immersed in 50 mL of a 50% aqueous ethanol solution twice, then immersed in 50 mL of absolute ethanol (3 times), and further immersed in 50 mL of methyl ethyl ketone (3 times). In addition, this operation is to treat with a solvent (methyl ethyl ketone) that easily penetrates before adding the curable compound for hydrophobic treatment, and since water and methyl ethyl ketone are not mixed, both before the methyl ethyl ketone treatment. First of all, it is replaced with ethanol mixed with. Then, it was immersed in 50 mL of alicyclic acid anhydride (manufactured by New Japan Chemical Co., Ltd., Ricacid MH-700) (3 times). In each case, the sample was soaked for 10 to 15 minutes while shaking lightly.

After immersing in the alicyclic acid anhydride, depressurization (less than 0.1 kPa) and sonication were repeated twice for 30 minutes each. By this operation, in order to bring the surface of the wood-based structure close to the alicyclic acid anhydride, air and the solvent can be removed to make only the alicyclic acid anhydride as much as possible. It was heated at 120 ° C. for 1 hour. Then, it was immersed in 50 mL of methyl ethyl ketone (three times). When the heated wood sample was dried under reduced pressure and the infrared absorption spectrum was evaluated, ^{the peak of 1710 cm -1} carboxylic acid increased, the peak of 3340 cm ^-1 hydroxyl group decreased, and carboxylic acid was generated on the wood surface. It was suggested that there was.

[Example 2]
Using the water-impregnated white wood (50 mm × 10 mm × 1 mm) obtained in Synthesis Example 2, alicyclic carboxylic acid was formed on the surface of the white wood using an alicyclic acid anhydride as in Example 1. (Composition) was prepared.

[Example 3: Resin impregnation + compression]
30.7 g of alicyclic epoxy compound (Ceroxide 2021P, manufactured by Daicel), 19.3 g of alicyclic acid anhydride (Recasid MH-700, manufactured by New Japan Chemical Co., Ltd.), curing catalyst (2E-4MZ, manufactured by Shikoku Kasei Co., Ltd.) ) 0.5 g and 21.4 g of methyl ethyl ketone were mixed at room temperature to obtain a resin composition.

The white wood (composition) prepared in Example 1 was immersed in the resin composition obtained above with occasional stirring (1 hour each, 3 times). Further, after newly exchanging with the same amount of resin composition, the mixture was allowed to stand under reduced pressure (0.1 kPa) for 20 minutes, and then ultrasonically treated for 30 minutes. This was repeated twice.

The resin composition on the surface of white wood impregnated with the resin composition is lightly wiped, heated at 110 ° C. for 30 minutes, and then the heat-dried resin-impregnated white wood is sandwiched between a polyethylene terephthalate film having a thickness of 50 μm. Was cured at 0.5 MPa at 130 ° C. for 30 minutes to obtain a transparent composition (thickness 0.8 mm) in which the white wood of Synthesis Example 1 was used as a matrix.

The transmittance of this composition at a wavelength of 500 nm was 72%, and the maximum bending load was higher than that of white wood.

The transmittance and bending load of the composition were measured as follows.

<Transmittance>
The transmittance at 25 ° C. and a wavelength of 500 nm was measured using an ultraviolet-visible-infrared spectrophotometer manufactured by JASCO Corporation (V-700 series manufactured by Shimadzu Corporation).

<Bending load (breaking strength)>
The three-point bending strength was measured using an Instron universal testing machine (manufactured by Instron Japan, type 1185), and the maximum bending load was evaluated as the breaking strength by the bending stress.

[Example 4: Resin impregnation + compression]
30.7 g of alicyclic epoxy compound (Ceroxide 2021P, manufactured by Daicel), 19.3 g of alicyclic acid anhydride (Recasid MH-700, manufactured by New Japan Chemical Co., Ltd.), curing catalyst (2E-4MZ, manufactured by Shikoku Kasei Co., Ltd.) ) 0.5 g and 21.4 g of methyl ethyl ketone were mixed at room temperature to obtain a resin composition.

The white wood (composition) prepared in Example 2 was immersed in the resin composition obtained above with occasional stirring (1 hour each, 3 times). Further, after newly exchanging with the same amount of the composition, the mixture was allowed to stand under reduced pressure (0.1 kPa) for 20 minutes, and then ultrasonically treated for 30 minutes. This was repeated twice.

Lightly wipe the resin composition on the surface of white wood impregnated with the resin composition, heat it at 110 ° C. for 30 minutes, and then sandwich the heat-dried resin-impregnated white wood in a polyethylene terephthalate film with a thickness of 50 μm. Was cured at 0.5 MPa at 130 ° C. for 30 minutes to obtain a transparent molded product (cured product) (thickness 0.4 mm) in which the white wood of Synthesis Example 1 was used as a matrix.

The transmittance of this composition at a wavelength of 500 nm was 80%, and the maximum bending load was higher than that of white wood.

[Example 5: Resin impregnation]
30.7 g of alicyclic epoxy compound (Ceroxide 2021P, manufactured by Daicel), 19.3 g of alicyclic acid anhydride (Recasid MH-700, manufactured by New Japan Chemical Co., Ltd.), and curing catalyst (2E-, manufactured by Shikoku Kasei). 0.5 g of 4MZ) was mixed at room temperature to obtain a resin composition.

Lightly wipe the resin composition on the surface of the white wood impregnated with the resin composition, sandwich the heat-dried resin-impregnated white wood in a polyethylene terephthalate film with a thickness of 50 μm, and pressurize with a 15 g weight using a heat-pressurized impregnation device. However, it was cured at 130 ° C. for 30 minutes to obtain a transparent molded product (cured product) (thickness 1.0 mm) in which the white wood of Synthesis Example 1 was used as a matrix.

The maximum bending load was higher than that of white wood.

[Example 6: Resin impregnation]
After impregnating one white wood (50 mm × 10 mm × 1 mm) obtained in Synthesis Example 2 with water, the solvent was lightly wiped off. Then, the sample was immersed in 50 mL of a 50% ethanol aqueous solution twice, and then immersed in 50 mL of absolute ethanol (three times). In each case, the sample was soaked for 10 to 15 minutes while shaking lightly. After that, 49.5 g of acrylic resin (Trimethylol Propane EO-added Triacrylate, Mn912, manufactured by Aldrich) and a curing catalyst (photopolymerization initiator) (manufactured by Tokyo Chemical Industry Co., Ltd., 2-hydroxy-2) were added to the white wood. -Methylpropiophenone) 0.5 g was immersed in a resin composition mixed at room temperature under light shielding with occasional stirring (1 hour each, 3 times). Further, after newly exchanging with the same amount of the composition, the mixture was allowed to stand under reduced pressure (0.1 kPa) for 20 minutes, and then ultrasonically treated for 30 minutes. This was repeated twice.

Lightly wipe the resin composition on the white wood surface impregnated with the resin composition, sandwich it between slide glasses, and irradiate each side with UV (wavelength 365 nm) 6 times alternately for 10 seconds (UV irradiation device PM25C-100, manufactured by Ushio). 30 mW / cm ² ) was performed to obtain a transparent molded product (cured product) (thickness 1 mm) in which the white wood of Synthesis Example 2 was used as a matrix.

[Example 7: Inorganic substance]
Using the alicyclic acid anhydride prepared in Example 1, lightly wipe the solvent of the white wood on which the alicyclic carboxylic acid was generated on the surface, immerse it in 50 mL of absolute ethanol twice, and then soak the sample in 50 mL of a 50% ethanol aqueous solution. Was immersed twice, and further immersed in 50 mL of water (3 times). After neutralization with a 0.1 N NaOH aqueous solution, the wood was washed with water until the pH reached 7, and the wood was filtered and air-dried. Then, it was immersed in a 10 wt% CuCl ₂ aqueous solution, washed with water until the pH reached 7, and then the wood was immersed in ethanol. In each case, the sample was soaked for 10 to 15 minutes while shaking lightly. The obtained wood was dried under reduced pressure to obtain wood on which Cu particles were supported. From the EDS analysis image of SEM, it was confirmed that Cu particles (atomic number concentration 4.7% based on oxygen) were supported on the surface of the wood.

[Example 8: Inorganic substance]
Using the alicyclic acid anhydride prepared in Example 1, lightly wipe the solvent of the white wood on which the alicyclic carboxylic acid was generated on the surface, immerse it in 50 mL of absolute ethanol twice, and then soak the sample in 50 mL of a 50% ethanol aqueous solution. Was immersed twice, and further immersed in 50 mL of water (3 times). After neutralization with a 0.1 N NaOH aqueous solution, the wood was washed with water until the pH reached 7, and the wood was filtered and air-dried. Then, it was immersed in a 10 wt% AgNO ₃ aqueous solution, washed with water until the pH reached 7, and immersed in ethanol. In each case, the sample was soaked for 10 to 15 minutes while shaking lightly. The obtained wood was dried under reduced pressure to obtain wood on which Ag particles were supported. From the EDS analysis image of SEM, it was confirmed that Ag particles (atomic number concentration 6.8% based on oxygen) were supported on the surface of the wood.

[Example 9: Dye]
Toluidine blue (manufactured by WALDECK, toluidine blue O) was diluted with water to obtain a 0.00025 wt% toluidine blue (TB) aqueous solution. Using the alicyclic acid anhydride prepared in Example 1, white wood having an alicyclic carboxylic acid formed on the surface was immersed in 50 g of a TB solution for 15 minutes. It was found that the toluidine blue in the TB solution was reduced because the transmittance of the TB solution was improved. In addition, a blue wood (composition) having a grain (the original grain remains) and adsorbing the pigment was obtained.

[Example 10: Dye]
One white wood (50 mm × 10 mm × 2 mm) obtained in Synthesis Example 1 was impregnated with water, the solvent was lightly wiped off, the sample was immersed once in 100 mL of a 60 wt% ethanol aqueous solution, and then immersed in 100 mL of water. (Twice).

Anthraquinone blue (manufactured by Sankyo Chemical Industry Co., Ltd.) was used as a dye, and this was diluted with water to obtain 500 g of an 0.01% by weight anthraquinone blue (AB) aqueous solution. The white wood after being immersed in water twice as described above was lightly wiped with water on the surface and then immersed in an AB aqueous solution warmed to 60 ° C.

10 g of sodium sulfate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) is dissolved in this aqueous solution, and then 5 g of sodium carbonate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) is added 5 times (25 g in total) every 10 minutes. It was.

After 30 minutes from the last injection, the blue wood obtained above is treated with 500 g of hot water at 95 ° C. for 15 minutes, and this operation is performed twice to remove the dye that has not been adsorbed, and the dye is adsorbed. Blue wood (composition) was obtained.

When the blue wood after hot water treatment was immersed in ethanol, the wood remained blue even after one week, and the solvent remained transparent without discoloration. From this, it was confirmed that the pigment was adsorbed on the white wood without changing with time.

[Example 11: Biodegradable resin / biological material]
The white wood obtained in Synthesis Example 1 was freeze-dried as follows.

Freeze-drying: After immersing the sample in a 50% ethanol aqueous solution, 10 to 10 samples are placed in each of a 70% ethanol aqueous solution, a 90% ethanol aqueous solution, a 95% ethanol aqueous solution, a 99.5% ethanol aqueous solution, and absolute ethanol (3 times). Soaked for about 15 minutes. Then, the sample was immersed in absolute ethanol: t-butyl alcohol = 1: 1 for about 15 to 30 minutes, and further immersed in t-butyl alcohol for 15 minutes or more. This operation was repeated 3 times. The solvent was lightly wiped from the sample and stored in a refrigerator for 15 minutes or more for freeze-drying.

Next, 6 g of cellulose acetate (Mn50000 manufactured by Aldrich) was dissolved in 48 g of dimethyl sulfoxide to obtain a cellulose solution. The freeze-dried white wood was immersed in a cellulose solution and allowed to stand under reduced pressure (0.1 kPa) for 20 minutes, and then ultrasonically treated for 30 minutes. This was repeated twice. The solution on the surface of the obtained cellulose acetate-impregnated wood was wiped off, the wood was immersed in a 0.1 N NaOH aqueous solution, washed with water to pH 7 after 24 hours, washed with ethanol, dried under reduced pressure, and white containing cellulose. Wood (composition) was obtained. The obtained white wood had a higher maximum load than the white wood before treatment. The content of amorphous cellulose derived from cellulose acetate in wood is 46.3% by weight. The content of amorphous cellulose in the composition was measured by the weight change before and after impregnation. Further, it is possible to calculate the content by decomposing and / or extracting each component of the composition and identifying it by HPLC or the like as in the analysis of wood.

[Example 12] (Biodegradable resin / biological material)
The white wood obtained in Synthesis Example 1 was freeze-dried in the same manner as in Example 11. 4 g of polylactic acid (manufactured by Aldrich, poly (D, L-lactide) Mn10000) was dissolved in 12 g of dichloromethane to obtain a polylactic acid solution. The freeze-dried white wood was immersed in a polylactic acid solution and ultrasonically performed for 30 minutes. This was repeated twice. The obtained polylactic acid-impregnated wood was dried under reduced pressure to obtain a white wood (composition) containing polylactic acid. The obtained white wood had a higher maximum load than the white wood before treatment. The content of polylactic acid in wood is 67.7% by weight. The content of polylactic acid in the composition was measured by the weight change before and after impregnation. Further, it is possible to calculate the content by decomposing and / or extracting each component of the composition and identifying it by HPLC or the like as in the analysis of wood.

[Comparative Example 1]
After heating the white wood of Synthesis Example 1 at 110 ° C. for 30 minutes, the white wood dried by heating is sandwiched between polyethylene terephthalate films having a thickness of 50 μm, and heat-compressed at 0.5 MPa, 130 ° C. for 30 minutes using a heat-pressurizing impregnation device. did. The transmittance of this composition at a wavelength of 500 nm was 0%, and the maximum bending load was smaller than that of the resin-impregnated wood of Examples 3 to 6.

[Comparative Example 2]
After heating the white wood of Synthesis Example 2 at 110 ° C. for 30 minutes, the white wood dried by heating is sandwiched between polyethylene terephthalate films having a thickness of 50 μm, and heat-compressed at 0.5 MPa, 130 ° C. for 30 minutes using a heat-pressurizing impregnation device. did. The transmittance of this composition at a wavelength of 500 nm was 0%, and the maximum bending load was smaller than that of the resin-impregnated wood of Examples 3 to 6.

This application is based on Japanese Patent Application No. 2019-155598, which was filed on August 28, 2019, and the entire disclosure content is incorporated herein by reference in its entirety.

Claims

Wood-based structures with a lignin content of less than 3% by weight, a cellulose content of 65% by weight or more, and a hemicellulose content of 0.01% by weight or more and 15% by weight or less, and curable compounds, resins, inorganic substances, and dyes. A composition comprising, and at least one selected from the group consisting of pigments.
From wood-based structures with a lignin content of less than 3% by weight, a cellulose content of 65% by weight or more, and a cellulose viscosity average degree of polymerization DPv of 300 or more, and curable compounds, resins, inorganic substances, dyes, and pigments. A composition comprising at least one selected from the group:
The composition according to claim 1 or 2, which is a porous body and has at least one selected from the group consisting of a curable compound, a resin, an inorganic substance, a dye, and a pigment attached to the surface.
The composition according to any one of claims 1 to 3, wherein the transmittance at a wavelength of 500 nm is 30% or more.
The composition according to any one of claims 1 to 4, wherein the resin is a biodegradable resin and / or a biological material, and contains 30% by weight or more of the resin.
The composition according to any one of claims 1 to 5, which has a grain on the surface.
The composition according to any one of claims 1 to 6, which contains 30% by weight or more of a biological material.
The composition according to any one of claims 1 to 7, which comprises the wood-based structure and the resin composition containing the curable compound.
The composition according to claim 8, wherein the curable compound is an epoxy compound.
The composition according to any one of claims 1 to 9, which is obtained by mixing the resin composition containing the curable compound with a wood-based structure and then curing the resin composition.