Method for manufacturing a molded body, method for processing a structure, method for manufacturing a composition, and composition

Abstract

To provide a molded article manufacturing method, a structure treatment method, a composition production method, and a composition that can improve a strength of the molded article.SOLUTION: The molded article manufacturing method according to the present disclosure includes preparing material containing at least one of lignin and cellulose, an inorganic solid material, and a basic material, preparing a mixture of the material containing at least one of the lignin and the cellulose, the inorganic solid material and the basic material, and subjecting the mixture to heating and pressurization.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a method for manufacturing a molded article, a method for processing a structure, a method for manufacturing a composition, and a composition. [Background technology]

[0002] In recent years, various materials have been developed for use in construction (see Patent Document 1). Generally, molded articles manufactured from such materials are required to have properties that meet certain standards (e.g., strength and water resistance) as construction materials. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-6610 [Overview of the project] [Problems that the invention aims to solve]

[0004] The present invention aims to provide a method for manufacturing a molded article, a method for processing a structure, a method for manufacturing a composition, and a composition, all of which can improve the properties of the molded article. [Means for solving the problem]

[0005] The inventors diligently studied how to improve the properties of molded articles in order to solve the above problems. As a result, they found that when manufacturing molded articles made from lignin and / or cellulose and inorganic solid materials, mixing a basic material with the raw materials improves the properties of the molded articles.

[0006] The present invention includes the following embodiments. [1] A method for producing a molded article, comprising: preparing a material containing at least one of lignin and cellulose, an inorganic solid material, and a basic material; preparing a mixture of the material containing at least one of lignin and cellulose, the inorganic solid material, and the basic material; and heating and pressurizing the mixture. [2] The method according to [1], wherein the material containing at least one of lignin and cellulose is of plant origin. [3] The method according to [1] or [2], wherein the inorganic solid material is one or more selected from the group consisting of one or more minerals, one or more metals, one or more ceramics, one or more glasses, one or more slags, one or more incinerator ashes, and composite materials thereof. [4] The method according to any one of [1] to [3], wherein the maximum particle size of the inorganic solid material is 50 nm or more and 10 cm or less. [5] The method according to any one of [1] to [4], wherein the total amount of the material containing at least one of lignin and cellulose and the inorganic solid material is 100 parts by mass, and the amount of the material containing at least one of lignin and cellulose added is 15 parts by mass or more and 99 parts by mass or less. [6] The method according to any one of [1] to [5], wherein the basic material comprises a basic solution. [7] The basic solution is an aqueous solution of one or more bases selected from the group consisting of calcium hydroxide, sodium hydroxide, sodium bicarbonate, sodium carbonate, potassium hydroxide, potassium bicarbonate, potassium carbonate, lithium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, barium hydroxide, zinc hydroxide, copper hydroxide, iron hydroxide, lead hydroxide, cobalt hydroxide, chromium hydroxide, zirconium hydroxide, nickel hydroxide, and ammonia, according to the method of [6]. [8] The concentration of the base in the basic solution is 1 × 10 -4 The method according to [6] or [7], wherein the concentration is between mol / L and 1 mol / L. [9] The method according to any one of [1] to [8], wherein the amount of material containing at least one of lignin and cellulose added is 50 parts by mass, and the amount of basic material added is 1 part by mass or more and 50 parts by mass or less.

[10] The mixture is pressurized at a temperature of 160°C to 240°C, according to any one of [1] to [9].

[11] The method according to any one of [1] to

[10] , wherein the three-point bending strength of the molded article is 5 MPa or more.

[12] A method for treating a structure comprising a material containing at least one of lignin and cellulose, and an inorganic solid material, the method comprising adding a basic material to the structure.

[13] A method for producing a composition, comprising: preparing a material containing at least one of lignin and cellulose, an inorganic solid material, and a basic material; and mixing the material containing at least one of lignin and cellulose, the inorganic solid material, and the basic material.

[14] A composition comprising a material containing at least one of lignin and cellulose, an inorganic solid material, and a basic material, wherein the basic material contains one or more bases selected from the group consisting of sodium hydroxide, sodium bicarbonate, sodium carbonate, potassium hydroxide, potassium bicarbonate, potassium carbonate, lithium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, barium hydroxide, zinc hydroxide, copper hydroxide, iron hydroxide, lead hydroxide, cobalt hydroxide, chromium hydroxide, zirconium hydroxide, nickel hydroxide, and ammonia. [Effects of the Invention]

[0007] According to embodiments of the present invention, it is possible to provide a method for manufacturing a molded article, a method for processing a structure, a method for manufacturing a composition, and a composition, all of which can improve the properties of the molded article. [Brief explanation of the drawing]

[0008] [Figure 1] A photograph of the manufactured molded product is shown. [Modes for carrying out the invention]

[0009] The following describes the manufacturing method of the molded article, the processing method of the structure, the manufacturing method of the composition, and the composition itself. Note that the following embodiments represent one aspect of the present invention and are not limiting, and can be modified as needed within the scope of the technical concept of the present invention.

[0010] <Method for manufacturing a compression molded body> According to one embodiment of the present invention, a method for manufacturing a molded article is provided, comprising: (1) preparing a material containing at least one of lignin and cellulose (hereinafter also referred to as the "first material"), an inorganic solid material, and a basic material; (2) preparing a mixture of the material containing at least one of lignin and cellulose, the inorganic solid material, and the basic material; and (3) heating and pressurizing the mixture.

[0011] The inventors have found that the above manufacturing method can improve the properties (e.g., strength and water resistance) of the resulting molded article compared to the case where basic materials are not used. For example, the following mechanism is hypothesized to improve the strength of the molded article. However, this is merely speculation and does not limit the present invention in any way.

[0012] It is presumed that the lignin contained in the first material reacts with basic materials to exhibit adhesive properties, thereby bonding the inorganic solid materials constituting the molded body and the components of the first material other than lignin to each other. Thus, it is thought that the strength of the molded body is improved by the function of lignin or lignin-derived components in the structure of the molded body as an adhesive.

[0013] Since the cellulose contained in the first material also exhibits an adhesive effect, it is presumed to function as a binder in the molded body. Alternatively, another mechanism may be considered in which the cellulose fibrils react with the basic material and shrink. That is, as a result of the shrinkage of the cellulose fibrils, deformation by hot compression is promoted, and the strength of the molded body is considered to be improved by efficiently filling the gaps in the molded body.

[0014] Also, when wood is used as the first material, since wood can flow under pressure when pressurized, a molded body with few internal gaps can be formed by performing pressure molding. Such a molded body can have a dense structure and high strength. Also, due to the above fluidity, a molded body with a complex shape can be manufactured.

[0015] Furthermore, lignin and cellulose are biodegradable and can be decomposed by specific microorganisms. Therefore, the manufactured molded body can be decomposed by microorganisms in the soil after being discarded. For this reason, the above method can suppress the disposal cost and environmental pollution.

[0016] Hereinafter, each of steps (1) to (3) of the above manufacturing method will be described.

[0017] (1) Preparation of raw materials First, a first material containing at least one of lignin and cellulose, an inorganic solid material, and a basic material are each prepared. In this specification, "each prepared" means that each material is prepared in a separated state from each other. Hereinafter, each material will be described in detail.

[0018] (1-a) First material containing at least one of lignin and cellulose As described above, the first material may have a function of improving the strength in the molded body to be manufactured. The first material is not particularly limited as long as it contains lignin and / or cellulose.

[0019] In this specification, "lignin" refers to a polymer whose basic structure is a polymer formed by the polymerization of lignin monomers, which may be partially substituted with substituents and may be bonded to or form complexes with other compounds. The type of lignin is not particularly limited, and may include S-type lignin, G-type lignin, H-type lignin, etc. The first material may contain lignin in a structure formed by the polymerization of one or more lignin monomers. Lignin may also contain monomers other than lignin monomers as polymerization units.

[0020] In this specification, "cellulose" means a polymer whose basic structure is a linear polymer of β-glucose linked by glycosidic bonds, which may be partially substituted with substituents, bonded to other compounds (e.g., lignin), or form complexes with other compounds.

[0021] (Type of material) The first material is, for example, a plant-derived material. Examples of the first material or its raw materials from a material standpoint include coniferous trees such as cedar, cypress, and pine; broad-leaved trees such as beech, chestnut, and maple; grasses such as bamboo; other plant materials (e.g., plant waste and residues discharged from plant factories); lignocellulose materials; and artificial materials (e.g., waste and residues containing lignin and / or cellulose discharged from paper mills).

[0022] The first material or its raw material is not particularly limited in terms of form, but examples include wood flour, wood chips, sawdust, plant stems and leaves, flowers, plant-derived waste and residues, etc. Furthermore, isolated lignin or cellulose, high-purity lignin or cellulose, or mixtures thereof may be used as the first material.

[0023] Plant-derived waste can be used as the primary material or its raw material. This is advantageous because it allows for the reuse of plant-derived resources that have not been adequately reused in the past, thus contributing to sustainability.

[0024] (Maximum particle size of the first material) The first material can be refined and / or sorted until the maximum particle size is within a desired range, for example, by crushing, chopping, or sieving the raw material. In this specification, "maximum particle size" means the size of the pores of a sieve used when sorting the "group of particles that passed through the sieve" from a group of particles using a mesh sieve with square pores of a predetermined size. That is, the maximum particle size of the "group of particles that passed through the sieve" is the size of the pores of the sieve used. The maximum particle size of the first material when mixed with other materials is, for example, between 50 nm and 100 mm. If the maximum particle size of the first material is less than 50 nm, the burden of crushing the material may become excessively large. If the maximum particle size of the first material is greater than 100 mm, the gaps between the constituent particles of the molded article may become large, potentially reducing the overall strength of the molded article. The maximum particle size of the first material is preferably 100 nm to 50 mm, 500 nm to 10 mm, 1 μm to 5 mm, 5 μm to 4 mm, 10 μm to 3 mm, 50 μm to 2 mm, 100 μm to 1 mm, 150 μm to 500 μm, or 200 μm to 300 μm. These upper and lower limits can be combined in any way.

[0025] (Amount of the first ingredient added) When the total amount of materials to be mixed is 100 parts by mass, the amount of the first material added is, for example, 10 parts by mass or more and 99 parts by mass or less. If the amount of the first material added is less than 10 parts by mass, the amount of lignin or cellulose contained in the molded article produced may be insufficient, and sufficient strength may not be obtained. If the amount of the first material added is more than 99 parts by mass, the amount of flammable components in the molded article may increase, and sufficient fire resistance may not be obtained. When the total amount of materials to be mixed is 100 parts by mass, the amount of the first material added is preferably 20 parts by mass or more and 90 parts by mass or less, 30 parts by mass or more and 80 parts by mass or less, 35 parts by mass or more and 70 parts by mass or less, or 40 parts by mass or more and 60 parts by mass or less. Note that these upper and lower limits can be combined arbitrarily.

[0026] (1-b) Inorganic solid materials Inorganic solid materials may have the function of improving durability (e.g., fire resistance and insect resistance) in the manufactured molded articles. The inorganic solid material may be any inorganic material that is solid at room temperature and pressure.

[0027] (Types of inorganic solid materials) The inorganic solid material is not particularly limited, but is one or more selected from the group consisting of, for example, one or more minerals, one or more metals, one or more ceramics, one or more glasses, one or more slags, and one or more incinerator ashes, as well as composite materials thereof.

[0028] In this specification, "mineral" may be a natural mineral, an artificial material, or a material of biological origin. Examples of minerals, or mixtures or composites of minerals, include sand, gravel, silt, clay, pebbles, stones, and diatomaceous earth.

[0029] In this specification, "metal" includes elemental metals and alloys. Examples of metals, from a material standpoint, include iron, steel, aluminum, copper, and brass. From a morphological standpoint, examples include fragments of ferrous and non-ferrous metals, cutting shavings, grinding shavings, empty cans, and metal scrap.

[0030] In this specification, "ceramics" means heat-treated inorganic materials. Examples of ceramics, from a material standpoint, include metal oxides, metal carbides, metal nitrides, and inorganic materials that do not contain metallic elements (e.g., diamond, silicon, carbon fiber, silicon carbide, fullerene, boron carbide). From a morphological standpoint, examples include ceramic fragments, brick scraps, tile scraps, and plaster scraps.

[0031] In this specification, "glass" means a solid material containing at least partially amorphous silicon oxide. Examples of glass, from a material standpoint, include soda-lime glass, quartz glass, silicate glass, and borosilicate glass. From a morphological standpoint, examples include fragments of glass containers and utensils, fragments of plate glass, glass fibers, and glass powder.

[0032] In this specification, "slag" refers to a by-product generated during the smelting of metals from ore. Examples of slag include blast furnace slag, steelmaking slag, and non-ferrous slag.

[0033] In this specification, "incinerator ash" refers to the powder remaining after a substance has been burned. Examples of incinerator ash include fly ash.

[0034] Preferably, the inorganic solid material comprises one or more materials selected from the group consisting of sand, gravel, stone, diatomaceous earth, metal scraps, ceramic scraps, brick scraps, and glass scraps. These materials are advantageous in that they are readily available and have not been fully utilized in the past.

[0035] Inorganic solid materials or their raw materials can be made from waste materials such as construction materials. This reuse of resources is advantageous both in terms of cost and sustainability.

[0036] Inorganic solid materials may include concrete rubble or fragments and powders obtained by crushing or breaking concrete. Conversely, inorganic solid materials do not necessarily have to contain concrete materials.

[0037] (Maximum particle size of inorganic solid materials) Similar to the first material, the inorganic solid material can be refined and / or sorted until the maximum particle size falls within a desired range, for example, by crushing or sieving the raw material. The maximum particle size of the inorganic solid material is, for example, 50 nm to 100 mm. If the maximum particle size of the inorganic solid material is less than 50 nm, the burden of crushing the material may become excessively large. If the maximum particle size of the inorganic solid material is greater than 100 mm, the gaps between the constituent particles of the molded body produced will become larger, potentially reducing the overall strength of the molded body. Preferably, the maximum particle size of the inorganic solid material is 100 nm to 50 mm, 500 nm to 10 mm, 1 μm to 5 mm, 5 μm to 4 mm, 10 μm to 3 mm, 50 μm to 2 mm, 100 μm to 1 mm, or 200 μm to 500 μm. These upper and lower limits can be combined arbitrarily.

[0038] (Amount of inorganic solid material added) When the total amount of materials to be mixed is 100 parts by mass, the amount of inorganic solid material added is, for example, 10 parts by mass or more and 80 parts by mass or less. If the amount of inorganic solid material added is less than 10 parts by mass, the amount of flammable components in the molded article will be high, and sufficient fire resistance may not be obtained. If the amount of inorganic solid material added is more than 80 parts by mass, the amount of lignin or cellulose contained in the manufactured molded article may be insufficient, and sufficient strength may not be obtained. When the total amount of materials to be mixed is 100 parts by mass, the amount of inorganic solid material added is preferably 20 parts by mass or more and 70 parts by mass or less, 30 parts by mass or more and 65 parts by mass or less, or 40 parts by mass or more and 60 parts by mass or less. Note that these upper and lower limits can be combined arbitrarily.

[0039] When the total amount of the first material containing at least one of lignin and cellulose and the inorganic solid material is 100 parts by mass, the amount of the first material added is, for example, 15 parts by mass or more and 99 parts by mass or less. That is, the amount of inorganic solid material added is, for example, 1 part by mass or more and 85 parts by mass or less, and the mass ratio of the first material to the inorganic solid material is, for example, 15:85 to 99:1. If the amount of the first material added is less than 15 parts by mass (i.e., the amount of inorganic solid material added is more than 85 parts by mass), the amount of lignin or cellulose contained in the molded article may be insufficient, and sufficient strength may not be obtained. If the amount of the first material added is more than 99 parts by mass (i.e., the amount of inorganic solid material added is less than 1 part by mass), the amount of flammable components in the molded article will be high, and sufficient fire resistance may not be obtained. In addition, the molded article may not have sufficient resistance to insect damage and mold growth. When the total amount of the material containing at least one of lignin and cellulose and the inorganic solid material is 100 parts by mass, the amount of the first material added is preferably 20 parts by mass or more and 90 parts by mass or less, 30 parts by mass or more and 80 parts by mass or less, 35 parts by mass or more and 70 parts by mass or less, 40 parts by mass or more and 60 parts by mass or less, or 45 parts by mass or more and 55 parts by mass or less. These upper and lower limits can be combined arbitrarily.

[0040] (1-c) Basic materials Basic materials may have the function of improving the properties of molded articles (e.g., strength and water resistance) by reacting with lignin and / or cellulose. The basic material is not particularly limited; any material that acts as a base can be used.

[0041] (Types of basic materials) As the basic material, a basic compound in solid (e.g., powder) or liquid state, or a solution in which a basic compound is dissolved, can be used. Preferably, the basic material includes a basic solution. Using a basic solution has advantages such as making it easier to add the basic material, making it easier to induce a uniform alkaline reaction, and allowing the basic material to penetrate into the microstructure of the particles of the first material or inorganic solid material.

[0042] The basic solution is not particularly limited, but for example, it is an aqueous solution of one or more bases selected from the group consisting of calcium hydroxide, sodium hydroxide, sodium bicarbonate, sodium carbonate, potassium hydroxide, potassium bicarbonate, potassium carbonate, lithium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, barium hydroxide, zinc hydroxide, copper hydroxide, iron hydroxide, lead hydroxide, cobalt hydroxide, chromium hydroxide, zirconium hydroxide, nickel hydroxide, and ammonia.

[0043] Industrial waste liquids and other waste materials can also be used as basic materials or their raw materials. This method allows for resource reuse, which is advantageous in terms of both cost and sustainability. As described above, the first material and the inorganic solid material can also be made from waste materials, so the manufacturing method as a whole can reuse waste materials.

[0044] (Concentration of basic solution) The concentration of a base in a basic solution is, for example, 1 × 10⁻⁶. -4 The concentration is between mol / L and 1 mol / L. The concentration of the basic solution is 1 × 10⁻⁶. -4 If the concentration is less than mol / L, the reaction between lignin or cellulose and the basic material may not proceed sufficiently, resulting in insufficient adhesion of lignin or cellulose and potentially failing to achieve sufficient strength in the molded article. If the concentration of the basic solution is greater than 1 mol / L, there may be an excess of basic material, which could be economically unfeasible. Preferably, the concentration of the base in the basic solution is 5 × 10⁻⁶. -4 mol / L or more and 0.5mol / L or less, 1×10 -3 mol / L or more and 0.1 mol / L or less, or 5 × 10⁻⁶ -3 mol / L or more 5×10 -2 The concentration must be mol / L or less. Note that these upper and lower limits can be combined in any way.

[0045] The pH value of the basic solution is not particularly limited, but for example, it may be 8 or higher, 9 or higher, 10 or higher, 11 or higher, 12 or higher, 13 or higher, or 14 or higher. Preferably, the pH value of the basic solution is greater than 13.

[0046] (Amount of basic solution added) When the amount of the first material containing at least one of lignin and cellulose is 50 parts by mass, the amount of the basic material added is, for example, 1 part by mass or more and 50 parts by mass or less. If the amount of the basic material added is less than 1 part by mass, the reaction between lignin or cellulose and the basic material may not proceed sufficiently, and the adhesion of lignin or cellulose may be insufficient, potentially resulting in insufficient strength in the molded article. If the amount of the basic material added exceeds 50 parts by mass, the basic material will be in excess, which may be economically unfeasible. Preferably, when the amount of the first material added is 50 parts by mass, the amount of the basic material added is 3 parts by mass or more and 40 parts by mass or less, 5 parts by mass or more and 30 parts by mass or less, or 8 parts by mass or more and 20 parts by mass or less. These upper and lower limits can be combined arbitrarily.

[0047] (1-d) Other ingredients In addition to the first material, the inorganic solid material, and the basic material, other materials may be added. For example, water, reinforcing materials, adhesives, and other optional additives can be added. The addition of water is preferable from the viewpoint of allowing the reaction between lignin and / or cellulose and the basic material to proceed sufficiently. The addition of reinforcing materials is preferable from the viewpoint of increasing the strength of the molded article. Reinforcing materials are not particularly limited, but examples include fibrous materials, glass fibers, plastics, and fiber-reinforced plastics. The addition of adhesives is preferable from the viewpoint of strengthening the bonding between the particles constituting the molded article. Adhesives are not particularly limited, but examples include epoxy adhesives, urethane adhesives, acrylic adhesives, and silicone adhesives.

[0048] (2) Preparation of the mixture Next, mix the prepared ingredients. There are no particular restrictions on the order in which the ingredients are added. All ingredients may be mixed together at once, or they may be mixed in multiple stages.

[0049] The method of mixing the materials is not particularly limited. For example, mixing methods include manual stirring, mortar and pestle (manual or automatic), ball mill, planetary mill, vibratory mill, rotor mill, hammer mill, disper mill, mixer, homogenizer, etc.

[0050] The conditions for mixing are not particularly limited. For example, materials can be mixed under atmospheric pressure at room temperature, but temperature, pressure, atmosphere, etc., can be set as appropriate.

[0051] By mixing the materials, a mixture (composition) containing the above-mentioned first material, inorganic solid material, and basic material is obtained. At this point, the chemical reaction between lignin and / or cellulose and the basic material may or may not have started.

[0052] (3) Heating and pressurizing the mixture Next, the resulting mixture is heated and pressurized. For example, a heat-compressed molded body can be manufactured by heating and pressurizing the resulting mixture. Heating and pressurizing can be performed, for example, by heating the mold containing the mixture with a heating device such as a hot plate while applying pressure to the inside of the mold. Heating and pressurizing can also be performed using a so-called hot press device, or any other method can be used.

[0053] (molding temperature) The mixture is pressurized at a temperature of, for example, 160°C to 240°C (molding temperature). If the molding temperature is below 160°C, the adhesion of lignin or cellulose may be insufficient, and sufficient strength may not be obtained in the molded article. If the molding temperature is above 240°C, the first material containing lignin or cellulose may carbonize. Preferably, the heating temperature is 165°C to 220°C, 170°C to 200°C, or 175°C to 190°C. These upper and lower limits can be combined arbitrarily.

[0054] (Molding pressure) The mixture is pressurized, for example, at a pressure of 0.1 MPa or higher (molding pressure). If the molding pressure is less than 0.1 MPa, the resulting molded article may not have sufficient strength. Preferably, the molding pressure is 1 MPa to 100 MPa, 5 MPa to 90 MPa, 10 MPa to 80 MPa, 20 MPa to 70 MPa, or 30 MPa to 60 MPa. These upper and lower limits can be combined arbitrarily. The pressure may be applied by any method. For example, the above pressure may be the atmospheric pressure inside the reaction vessel, or it may be applied by applying external press pressure, or by using both atmospheric pressure and press pressure of the same or different magnitudes simultaneously.

[0055] (Molding time) The mixture is pressurized, for example, at the molding temperature described above for a period of 10 seconds or more (molding time). If the molding time is less than 10 seconds, the resulting molded article may not have sufficient strength. Preferably, the molding time is 30 seconds to 1 hour, 1 minute to 30 minutes, or 5 minutes to 10 minutes. These upper and lower limits can be combined in any way.

[0056] (Additional processing to the molded product) The resulting molded article may have its strength improved by any method. For example, the above manufacturing method may include steps such as pressing the molded article, further heat treatment of the molded article, and blowing carbon dioxide gas onto the molded article.

[0057] <Molded body> According to one embodiment of the present invention, a molded article manufactured by the above manufacturing method is provided.

[0058] The molded body is a hardened body comprising, for example, a material containing at least one of lignin and cellulose, an inorganic solid material, and a basic material. For example, at least a portion of the lignin and / or cellulose contained in the molded body is modified by a chemical reaction with the basic material. The molded body may contain concrete-derived material in part, but preferably does not contain concrete material.

[0059] When the total amount of material containing at least one of lignin and cellulose and inorganic solid material contained in the molded article is 100 parts by mass, the amount of material containing at least one of lignin and cellulose contained in the molded article is, for example, 15 parts by mass or more and 99 parts by mass or less, preferably 20 parts by mass or more and 90 parts by mass or less, 30 parts by mass or more and 80 parts by mass or less, 35 parts by mass or more and 70 parts by mass or less, 40 parts by mass or more and 60 parts by mass or less, or 45 parts by mass or more and 55 parts by mass or less. These upper and lower limits can be combined arbitrarily.

[0060] The molded body can be formed to have any desired size, shape, structure, density, mass, strength, rigidity, hardness, water resistance, heat resistance, etc., depending on the application, by appropriately changing the raw materials used, molding temperature during pressurization, molding pressure, molding time, and the size and shape of the mold used during pressurization.

[0061] The molded body can be used for any purpose, for example, as a material for construction materials, buildings, furniture, carpets, containers, interior goods, tableware, or decorative items. While the production of cement, a raw material for concrete and mortar commonly used as construction materials, generates a large amount of CO2, using the molded body of this embodiment as a concrete substitute eliminates the need for cement, thereby reducing CO2 emissions. Furthermore, the estimated remaining reserves of limestone, the main raw material for cement, in Japan are estimated to be only a few decades to over a hundred years, raising concerns about resource depletion. Using the molded body of this embodiment as a concrete substitute contributes to the sustainable use of resources, even from the perspective of waste recycling.

[0062] Generally, alternative construction materials that do not use concrete or have a low concrete content often have inferior strength. There is a need to improve the strength of such concrete alternative construction materials. The molded body of this embodiment can exhibit greater three-point bending strength compared to those manufactured without using basic materials. This will be demonstrated in the examples described later.

[0063] The molded article has, for example, a three-point bending strength of 5 MPa or more. This three-point bending strength value is the standard for bending strength of interlocking blocks for roadway pavement as specified in JIS A 5371:2016. In this specification, the three-point bending strength is measured by a three-point bending strength test conducted in accordance with JIS A 1509-4:2014. Preferably, the three-point bending strength of the molded article is 6 MPa or more, 7 MPa or more, 8 MPa or more, 9 MPa or more, or 10 MPa or more, and 50 MPa or less, 30 MPa or less, or 20 MPa or less.

[0064] The molded articles of this embodiment may exhibit higher water resistance compared to those manufactured without the use of basic materials. For example, while molded articles manufactured without basic materials may disintegrate when immersed in water, such disintegration can be suppressed in the molded articles of this embodiment manufactured using basic materials. Furthermore, compared to a molded article manufactured using the first material, an inorganic solid material, and a basic material, the amount of water absorbed and / or volume expansion due to water absorption when exposed to water can be suppressed compared to a molded article in which concrete is added as the inorganic solid material and no separate basic material is used (since concrete can be both an inorganic solid material and a basic material, this molded article can be said to be a molded article manufactured from the first material and an inorganic solid material, or a molded article manufactured from the first material and a basic material). This will be demonstrated in the embodiments described later.

[0065] <Methods for treating structures> According to one embodiment of the present invention, a method for treating a structure comprising a material containing at least one of lignin and cellulose, and an inorganic solid material, is provided, the method comprising adding a basic material to the structure.

[0066] The above method is, for example, a method for improving the properties of a structure by treating the structure with a basic material. The above method is based on the above mechanism, in which the properties of a molded article are improved by the reaction between lignin and / or cellulose and a basic material. That is, by adding the above basic material to a structure containing lignin and / or cellulose, the properties of the structure, such as strength and water resistance, can be improved. The above method can reinforce a structure by improving its strength and water resistance. In this specification, "reinforcement" means improving the physical strength of the object, its resistance to internal factors such as aging deterioration, and / or its resistance to external factors such as other substances or physical conditions.

[0067] The structure to be subjected to the above method is not particularly limited in size, shape, structure, properties, etc., except that it contains the above-mentioned materials. The above-mentioned basic material can be used as the basic material used in the above method. When the amount of material containing at least one of lignin and cellulose contained in the structure is 50 parts by mass, the amount of basic material added is, for example, 1 part by mass or more and 50 parts by mass or less. Preferably, the amount of basic material added is 3 parts by mass or more and 40 parts by mass or less, 5 parts by mass or more and 30 parts by mass or less, or 8 parts by mass or more and 20 parts by mass or less. These upper and lower limits can be combined arbitrarily.

[0068] The above method can be used to treat the entire structure or only a portion of the structure. For example, this method can increase the three-point bending strength of the structure.

[0069] <Method for producing the composition> According to one embodiment of the present invention, a method for producing a composition is provided, comprising: (1) preparing a material containing at least one of lignin and cellulose, an inorganic solid material, and a basic material; and (2) mixing the material containing at least one of lignin and cellulose, the inorganic solid material, and the basic material. By this method, a composition to be used as a material for a molded article can be produced.

[0070] The method for producing this composition can be considered as taking a part of the above-described method for producing a molded article (i.e., steps (1) and (2)). In other words, steps (1) and (2) in the method for producing the composition are the same as steps (1) and (2) in the above-described method for producing a molded article.

[0071] <Composition> According to one embodiment of the present invention, a composition produced by the above method is provided. The composition comprises, for example, a material containing at least one of lignin and cellulose, an inorganic solid material, and a basic material, wherein the basic material contains one or more bases selected from the group consisting of sodium hydroxide, sodium bicarbonate, sodium carbonate, potassium hydroxide, potassium bicarbonate, potassium carbonate, lithium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, barium hydroxide, zinc hydroxide, copper hydroxide, iron hydroxide, lead hydroxide, cobalt hydroxide, chromium hydroxide, zirconium hydroxide, nickel hydroxide, and ammonia.

[0072] The composition can be molded into a molded body by heating and pressurizing. The form of the composition is not particularly limited, but a powdered mixture is advantageous, for example, because it is easy to press-mold. [Examples]

[0073] Examples of the present invention will be described below. These examples are not intended to limit the present invention.

[0074] [Example 1-1] (Manufacturing of raw material compositions) Sugi wood chips were prepared as the raw material of the first material, crushed, and sieved through a sieve with a pore size of 0.3 mm to obtain a first material with a maximum particle size of 0.3 mm. Sand was prepared as the raw material of the inorganic solid material, crushed, and sieved through a sieve with a pore size of 0.3 mm to obtain an inorganic solid material with a maximum particle size of 0.3 mm. The obtained first material and inorganic solid material were mixed so that the mass ratio was 1:1. Calcium hydroxide Ca(OH)2 was dissolved in water to a concentration of 5.0×10 -4 mol / L to prepare a basic solution. 10 parts by mass of the basic solution was added to 100 parts by mass of the mixture of the first material and the inorganic solid material (that is, a mixture of 50 parts by mass of the first material and 50 parts by mass of the inorganic solid material) and mixed. Thereby, a powdery raw material composition was obtained.

[0075] (Manufacture of molded body) Using a hot compression molding machine (small hot press machine H300-15, manufactured by AS ONE Corporation), the raw material composition was hot-compressed. After placing the molding die on the hot plate and heating it to 180°C, the powder of the raw material composition was put into the die. A pressure of 50 MPa was applied to the dry powder by the hot compression molding machine. After applying the pressure for 5 minutes, the pressure was released, and the hot-compressed raw material composition was demolded to obtain a hot-compressed molded body. A photograph of the obtained molded body is shown in FIG. 1.

[0076] [Examples 1-2 to Examples 4-2] (Change in type and concentration of base) In Examples 1-2 to Examples 4-2, as shown in Tables 1 to 3 below, the type and concentration of the basic compound used were variously changed from Example 1-1. Specifically, any one of sodium hydroxide, sodium hydrogen carbonate, and sodium carbonate was used instead of calcium hydroxide, and the concentration was set to any one of 5.0×10 -4 mol / L to 0.1 mol / L.

[0077] [Comparative Example 1] (No use of base) In Comparative Example 1, a molded body was obtained by hot-compressing a mixture of wood powder and sand without adding a basic solution.

[0078] [Comparative Example 2] (Concrete is used as the inorganic solid material.) In Comparative Example 2, a molded body was obtained in the same manner as in Example 1-1, except that crushed concrete (maximum particle size 0.3 mm) was used instead of sand as the inorganic solid material, and 10 parts by mass of water was added instead of a basic solution.

[0079] [Evaluation of molded products (1): Bending strength] The resulting heat-compressed molded articles were subjected to a three-point bending test to measure their bending strength. The three-point bending test was conducted in accordance with JIS A 1509-4:2014. The measured bending strengths are shown in Tables 1 to 3 below.

[0080] As shown in Tables 1 to 3, the bending strength of all examples exceeded that of Comparative Example 1, which did not have a basic solution added. Thus, it was confirmed that the bending strength of the heat-compressed molded article was improved by basic treatment of the mixture of wood powder and sand.

[0081] [Table 1] [Table 2] [Table 3]

[0082] [Evaluation of molded products (2): Water resistance] The heat-compressed molded articles obtained in Examples 1-2, 2-2, 2-8, and Comparative Examples 1 and 2 were immersed in water for 24 hours and then removed. Except for Comparative Example 1, an increase in the thickness and mass of the molded articles was observed before and after the immersion experiment. The "thickness increase rate due to immersion" was calculated by dividing the increase in thickness before and after immersion by the thickness before immersion. The "mass increase rate due to immersion" was calculated by dividing the increase in mass before and after immersion by the mass before immersion. In Comparative Example 1, the molded article collapsed when immersed in water. The results are shown in Table 4 below.

[0083] In Comparative Example 1, which did not use a basic material, the molded body disintegrated when immersed in water. In contrast, the molded bodies of Examples 1-2, 2-2, and 2-8, which used a basic material, did not undergo such disintegration, and were confirmed to have higher water resistance than Comparative Example 1. Furthermore, as shown in Table 4, the rate of thickness increase and mass increase upon immersion in Examples 1-2, 2-2, and 2-8, which used sand as the inorganic solid material, were smaller compared to Comparative Example 2, which used concrete as the inorganic solid material. In other words, Examples 1-2, 2-2, and 2-8 absorbed less water and were confirmed to have higher water resistance compared to Comparative Example 2.

[0084] [Table 4]

[0085] [Examples 5-1 to 6-3] (Changing the maximum particle size of the sand) In Examples 5-1 to 6-3, the maximum particle size of the inorganic solid material (sand) was varied by changing the sieve used, as shown in Table 5 below. In Examples 5-1 to 5-3, the basic solution was 1.0 × 10⁻⁶ -3 A mol / L aqueous solution of calcium hydroxide was used. In Examples 6-1 to 6-3, a 0.1 mol / L aqueous solution of sodium hydroxide was used as the basic solution.

[0086] As shown in Table 4, regardless of the maximum sand particle size, the flexural strength of Examples 5-1 to 6-3 exceeded the 5 MPa standard for flexural strength of interlocking block road pavement specified in JIS A 5371:2016. Thus, it was confirmed that sufficient flexural strength can be obtained for sand of various sizes.

[0087] [Table 5]

Claims

1. A method for manufacturing a molded article, Prepare materials containing lignin, inorganic solid materials, and basic materials, respectively. To prepare a mixture of the lignin-containing material, the inorganic solid material, and the basic material, The mixture is heated and pressurized, Includes, The inorganic solid material is one or more minerals selected from the group consisting of sand, gravel, silt, clay, pebbles, stone, and diatomaceous earth, and the maximum particle size of the inorganic solid material is 50 nm or more and 10 cm or less. The basic material is an aqueous solution of one or more bases selected from the group consisting of calcium hydroxide, sodium hydroxide, sodium bicarbonate, sodium carbonate, potassium hydroxide, potassium bicarbonate, potassium carbonate, lithium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, barium hydroxide, zinc hydroxide, copper hydroxide, iron hydroxide, lead hydroxide, cobalt hydroxide, chromium hydroxide, zirconium hydroxide, nickel hydroxide, and ammonia, wherein the concentration of the base in the aqueous solution is 1 × 10⁻⁴ mol / L or more and 1 mol / L or less. With respect to a total of 100 parts by mass of the lignin-containing material and the inorganic solid material, the lignin-containing material is in an amount of 30 parts by mass or more and 80 parts by mass or less. With respect to 50 parts by mass of the lignin-containing material, the basic material is 8 parts by mass or more and 20 parts by mass or less. The heating temperature is between 160°C and 240°C. The pressure of the aforementioned pressurization is between 10 MPa and 80 MPa. method.

2. The aforementioned lignin-containing material is of plant origin. The method according to claim 1.

3. The method according to claim 1 or 2, wherein the inorganic solid material is sand.

4. The method according to any one of claims 1 to 3, wherein the basic material is an aqueous solution of one or more bases selected from the group consisting of calcium hydroxide, sodium hydroxide, sodium bicarbonate, and sodium carbonate.

5. The three-point bending strength of the molded body is 5 MPa or more. The method according to any one of claims 1 to 4.

6. A method for manufacturing a composition for producing a molded article, Prepare materials containing lignin, inorganic solid materials, and basic materials, respectively. Mixing the material containing at least one of lignin and cellulose with the inorganic solid material and the basic material, Includes, The inorganic solid material is one or more minerals selected from the group consisting of sand, gravel, silt, clay, pebbles, stone, and diatomaceous earth, and the maximum particle size of the inorganic solid material is 50 nm or more and 10 cm or less. The basic material is an aqueous solution of one or more bases selected from the group consisting of calcium hydroxide, sodium hydroxide, sodium bicarbonate, sodium carbonate, potassium hydroxide, potassium bicarbonate, potassium carbonate, lithium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, barium hydroxide, zinc hydroxide, copper hydroxide, iron hydroxide, lead hydroxide, cobalt hydroxide, chromium hydroxide, zirconium hydroxide, nickel hydroxide, and ammonia, wherein the concentration of the base in the aqueous solution is 1 × 10⁻⁴ mol / L or more and 1 mol / L or less. With respect to a total of 100 parts by mass of the lignin-containing material and the inorganic solid material, the lignin-containing material is in an amount of 30 parts by mass or more and 80 parts by mass or less. With respect to 50 parts by mass of the lignin-containing material, the basic material is 8 parts by mass or more and 20 parts by mass or less. The molded article is manufactured by heating the composition at 160°C to 240°C and pressurizing it at 10 MPa to 80 MPa. method.

7. The material comprises a lignin-containing material, an inorganic solid material, and a basic material. The inorganic solid material is one or more minerals selected from the group consisting of sand, gravel, silt, clay, pebbles, stone, and diatomaceous earth, and the maximum particle size of the inorganic solid material is 50 nm or more and 10 cm or less. The basic material is an aqueous solution of one or more bases selected from the group consisting of sodium hydroxide, sodium bicarbonate, sodium carbonate, potassium hydroxide, potassium bicarbonate, potassium carbonate, lithium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, barium hydroxide, zinc hydroxide, copper hydroxide, iron hydroxide, lead hydroxide, cobalt hydroxide, chromium hydroxide, zirconium hydroxide, nickel hydroxide, and ammonia, wherein the concentration of the base in the aqueous solution is 1 × 10⁻⁴ mol / L or more and 1 mol / L or less. With respect to a total of 100 parts by mass of the lignin-containing material and the inorganic solid material, the lignin-containing material is in an amount of 30 parts by mass or more and 80 parts by mass or less. With respect to 50 parts by mass of the lignin-containing material, the basic material is 8 parts by mass or more and 20 parts by mass or less. A composition for manufacturing a molded article by heating at 160°C to 240°C and pressurizing at 10 MPa to 80 MPa.

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