Laminated material, method for producing same, and use application of same

Abstract

This laminated material comprises a first base material and a sheet material laminated on the surface of the first base material so as to be integrated with the first base material. The material for the first base material is selected from the group consisting of a biomass material, a plastic material, a metal, a ceramic material, a glass, a pulp mold and paper. The sheet material is substantially formed from a plant-derived component. The infrared absorption spectrum of the sheet material has an absorption peak in a range from 1715 to 1725 cm-1. This sheet material is produced by removing a liquid component from a plant solution produced by dissolving a plant raw material in an organic acid. The sheet material is laminated and pressure-bonded onto the surface of the first base while heating, thereby producing the laminated material. A method for modifying the surface of a molded article includes laminating and pressure-bonding the sheet material onto the surface of the molded article while heating. An adhesive agent comprises a plant solution or a sheet material.

Description

Laminated material, its manufacturing method and application

[0001] The present disclosure relates to laminated materials. More particularly, the present disclosure relates to laminated materials utilizing plant materials and methods for surface modification.

[0002] Conventionally, plant materials, such as wood, have been used for various purposes, such as building materials and furniture components. In particular, the use of high-quality wood is preferred for the surface layer of components, as it provides a beautiful, luxurious appearance and a pleasant feel. However, high-quality wood is generally expensive. Furthermore, due to the depletion of forest resources in recent years, it has become difficult to obtain high-quality wood. Furthermore, wood is difficult to press and mold, and must be cut and processed.

[0003] Techniques for bonding thin wood slices to various substrates have been disclosed. For example, Japanese Utility Model Laid-Open Publication No. 5-35208 (Patent Document 1) proposes a decorative board that expresses a more luxurious wood texture by carving different pseudo-vascular groove recesses into the surface of a wood board without concealing the original surface vascular groove recesses. Japanese Patent Laid-Open Publication No. 5-50408 (Patent Document 2) discloses a decorative building material in which a wood grain pattern that gives a luxurious feel to the surface of a wood board is formed by pressing the surface of the wood board to form a wood grain-like uneven pattern and coloring it. Japanese Patent Laid-Open Publication No. 8-60800 (Patent Document 3) proposes a composite wood column in which a rectangular core wood is located in the center and a planar covering wood is located around the core wood, and the core wood and covering wood are bonded together. Patent Document 3 discloses a technology for providing a high-quality wood column at an affordable price by using high-quality wood as the covering wood.

[0004] Japanese Patent Publication No. 2017-18543 (Patent Document 4) discloses a method for recovering chests of drawers made of solid wood, in which old, large furniture with deteriorated wood is disassembled, the solid wood surfaces of each piece are polished and painted, and then reassembled to form a finished piece of furniture. Japanese Patent Publication No. 2017-176992 (Patent Document 5) proposes a scratch repair painting method for repairing scratches on the surface of wood material. This method includes a putty application process, a flushing process, a curing process, a surface polishing process, a sealant application process, a sealant removal process, and a coloring process. Japanese Patent Publication No. 3956375 (Patent Document 6) discloses a method for repairing scratches on wooden products, including a process of filling scratches in the wooden product with a filler made of a synthetic resin material and a process of applying an instant adhesive and an instant adhesive curing accelerator to the surface and surrounding area of ​​the filled area.

[0005] On the other hand, binderless wood materials are also being investigated. For example, Japanese Patent Laid-Open Publication No. 2008-260238 (Patent Document 7) discloses a plant fiber molded body obtained by a mat-forming step of forming a mat containing plant fibers, a steam treatment step of exposing the mat to steam at a temperature of 150°C or higher, and a molding step of shaping the steam-treated mat under pressure to obtain a molded body.

[0006] JP 2014-019033 A (Patent Document 8) proposes an oil palm molded body obtained by stacking multiple oil palm thin plates with their fiber directions crossed and then applying a compressive force perpendicular to the surfaces of the stacked oil palm thin plates. JP 2018-64934 A (Patent Document 9) discloses a birch bark-derived laminate in which the layers are fixed to each other by adhesive bonds formed by heat introduction.

[0007] As environmental pollution has become a serious problem in recent years, pulp molds have been attracting attention as a material that can help eliminate plastics. Pulp molds are paper products made by dissolving and entangling plant fibers (mainly waste paper) in water, papermaking them in a mold, and then drying them. They are primarily used as packaging containers. Furthermore, a thermoformed molding technique has been proposed to obtain thinner, more complex-shaped pulp molds. However, because pulp molds are made of paper, they are permeable and breathable, which poses a challenge in that they cannot be used for some applications.

[0008] As a material with reduced water permeability and breathability, Japanese Patent Laid-Open Publication No. 2000-309322 (Patent Document 10) discloses a waterproof pulp molded container in which a synthetic resin film layer is laminated on one side of a pulp molded product and a waterproof layer is either laminated on the other side of the product or coated with a waterproof paint.

[0009] Japanese Utility Model Application Publication No. 5-35208, Japanese Patent Application Publication No. 5-50408, Japanese Patent Application Publication No. 8-60800, Japanese Patent Application Publication No. 2017-18543, Japanese Patent Application Publication No. 2017-176992, Japanese Patent No. 3956375, Japanese Patent Application Publication No. 2008-260238, Japanese Patent Application Publication No. 2014-019033, Japanese Patent Application Publication No. 2018-64934, Japanese Patent Application Publication No. 2000-309322

[0010] The techniques of Patent Documents 1 and 2 can create a desired sense of luxury in ceiling materials and the like that can be observed with the naked eye from a distance of 1 m or more, but for furniture, fittings, etc. that can be viewed from within 30 cm, for example, the sense of luxury that is obtained from natural wood may not be achieved due to a strong artificial and unnatural feel.The technique of Patent Document 3 provides a product that is made of almost 100% wood material, excluding the adhesive, and has an appearance similar to that of high-quality wood, but the problem remains that high-quality wood of a size suitable for covering material is itself expensive and difficult to obtain.

[0011] The methods disclosed in Patent Documents 4-6 use non-wood materials such as paints, adhesives, putties, and sealers. Therefore, these products are not 100% plant-based, nor can they be labeled as solid wood. Furthermore, for example, petroleum-derived synthetic adhesives, such as isocyanate adhesives, are used to bond wood pieces together. Synthetic adhesives are also used to bond wood (thinly sliced ​​boards, etc.) to the surfaces of plastic, metal, ceramic materials, etc. This raises concerns about odors caused by adhesives and the so-called sick building syndrome caused by the chemicals contained in them. Furthermore, the sawdust from these products also contains adhesives, which could potentially generate toxic gases when incinerated.

[0012] Patent documents 7 to 9 propose wood materials that do not use adhesives, but because they use lignin, hemicellulose, or trace components in bark as adhesive components, sufficient adhesive strength may not be obtained. Also, although adhesive strength can be improved by steam heating, subsequent dehydration and drying processes are required, which has the drawback of making the process complicated.

[0013] Furthermore, the technology disclosed in Patent Document 10 also uses a synthetic resin film, so it is not possible to obtain a 100% bio-based product, and most of the technology has poor biodegradability. No technology has yet been proposed that improves the air permeability and water permeability of pulp mold to obtain a 100% bio-based product.

[0014] An object of the present disclosure is to provide a technique for laminating and bonding sheet materials made from 100% plant materials to various substrates without using adhesives containing synthetic resins, organic solvents, etc. Another object of the present disclosure is to provide a laminated material that does not contain organic solvents, etc., and has a good appearance derived from plant materials, and a method for manufacturing the same. A still further object of the present disclosure is to provide a technique for bonding various substrates together using sheet materials that are 100% bio-based and highly biodegradable, without using adhesives containing synthetic resins, organic solvents, etc. A still further object of the present disclosure is to provide a method for modifying the surface of a wood-based molded product without using organic solvents, etc.

[0015] The laminated material of the present disclosure includes a first substrate and a sheet material laminated and integrated onto the surface of the first substrate. The material of the first substrate is selected from the group consisting of biomass materials, plastics, metals, ceramics, glass, pulp molds, and paper. The sheet material is formed substantially from plant-derived components. The infrared absorption spectrum of the sheet material is 1715 to 1725 cm －１ It shows an absorption peak in the region.

[0016] The density of the sheet material is 0.2 g / cm ３ 1.2g / cm or more ３ It may be the following:

[0017] The plant-derived component may be one or more selected from the group consisting of cellulose, hemicellulose, and lignin. Some or all of the hydroxyl groups of the cellulose, hemicellulose, and lignin may be formylated.

[0018] The sheet material may contain di- or higher hydroxylic fatty acids and / or anhydrides thereof.

[0019] The laminate may further include a second substrate laminated and bonded to the first substrate via the sheet material, and the material of the second substrate may be selected from the group consisting of biomass material, plastic, metal, ceramic, glass, molded pulp, and paper.

[0020] In another aspect, the present disclosure relates to a sheet material for use in any of the aforementioned laminates.

[0021] Any of the above-described methods for producing a laminated material includes (1) dissolving a plant material in an organic acid to obtain a plant solution, (2) removing a liquid component from the obtained plant solution to obtain a sheet material formed substantially from plant-derived components, and (3) laminating the sheet material on a surface of a first substrate and heat-pressing the laminated material to obtain a laminated material in which the sheet material and the first substrate are integrated. This production method may further include polishing the first substrate before laminating the sheet material.

[0022] From another perspective, a method for producing a laminated material includes: (1) dissolving a plant material in an organic acid to obtain a plant solution; (2) removing a liquid component from the obtained plant solution to obtain a sheet material formed substantially from plant-derived components; and (3) placing the sheet material between the first substrate and the second substrate and heat-pressing the sheet material to laminate and bond the first substrate and the second substrate together. This production method may further include polishing the first substrate and the second substrate before placing the sheet material.

[0023] The plant material may be woody biomass, herbaceous biomass, or a mixture thereof. The organic acid may be one or more selected from the group consisting of formic acid, glyoxylic acid, and pyruvic acid.

[0024] The temperature at which the plant raw material is dissolved in the organic acid may be 40° C. or higher and 80° C. or lower. The temperature at which the thermocompression is performed may be 220° C. or lower.

[0025] From yet another aspect, the present disclosure relates to a method for modifying the surface of a molded article, the method comprising: (1) dissolving a plant material in an organic acid to obtain a plant solution; (2) removing a liquid component from the obtained plant solution to obtain a sheet material formed substantially from plant-derived components; and (3) laminating the sheet material on a surface of the molded article and thermocompressing the sheet material.

[0026] The adhesive of the present disclosure includes a plant solution obtained by dissolving a plant material in an organic acid, and / or a sheet material substantially composed of plant-derived components obtained by removing the liquid component from the plant solution. The plant material may be woody biomass, herbaceous biomass, or a mixture thereof. The sheet material may contain a divalent or higher fatty acid and / or an anhydride thereof. The organic acid may be one or more selected from the group consisting of formic acid, glyoxylic acid, and pyruvic acid.

[0027] From another perspective, the adhesive of the present disclosure includes a plant solution obtained by dissolving a plant raw material in an organic acid. The plant solution contains plant-derived components, and the plant-derived components are one or more selected from the group consisting of cellulose, hemicellulose, and lignin. Some or all of the hydroxyl groups of the cellulose, hemicellulose, and lignin may be formylated.

[0028] According to the manufacturing method of the present disclosure, various plant materials, such as small pieces of wood and wood flour, can be used as raw materials for the plant solution and sheet material. Therefore, even if the substrate material is low-quality wood, a laminated material with the desired luxurious feel can be obtained by laminating a sheet material obtained from wood flour generated during the sawing of high-quality wood onto the substrate. Furthermore, this sheet material can be bonded and integrated with substrates made of various materials without the use of chemicals such as adhesives. According to the present disclosure, a laminated material can be provided that has the tactile feel and aesthetic appearance derived from plant materials and is free of organic solvent residues. Furthermore, by laminating this sheet material, the surface of molded products made of various materials can be modified without the use of chemicals such as adhesives. Furthermore, according to the present disclosure, an adhesive that does not contain organic solvents can be obtained.

[0029] FIG. 1 is a photograph of the appearance of the laminate of Example 85. FIG. 2 is a photograph of the appearance of the laminate of Example 87. FIG. 3 is a photograph of the appearance of Example 41. FIG. 4 is a photograph of the appearance of the laminate of Example 43. FIG. 5 is a photograph of the appearance of the substrate used in the production of the laminate of FIGS. 1 and 2. FIG. 6 is a photograph of the appearance of the substrate used in the production of the laminate of FIGS. 3 and 4. FIG. 7 is a photograph of the appearance of the sheet material of Production Example 1. FIG. 8 is a photograph of the appearance of the sheet material of Production Example 2. FIG. 9 is a photograph of the appearance of the sheet material of Production Example 5. FIG. 10 is an electron microscope photograph (magnification 500x) showing the surface condition of the sheet material of Production Example 1. FIG. 11 is an electron microscope photograph (magnification 500x) showing the surface condition of the sheet material of Production Example 4. FIG. 12 is a photograph of the appearance of the laminate of Example 130. FIG. 13 is a photograph of the appearance of the laminate of Example 131. Figure 14 is a photograph of the appearance of the laminated material of Example 133. Figure 15 is a photograph of the appearance of the laminated material of Example 137. Figure 16 is a photograph of the appearance of the laminated material of Example 138. Figure 17 is a photograph of the appearance of the laminated material of Example 139. Figure 18 is a photograph of the appearance of the laminated material of Example 142. Figure 19 is a photograph of the appearance of the sheet material of Production Example 8. Figure 20 is a photograph of the appearance of the sheet material of Production Example 9. Figure 21 is a photograph of the appearance of the sheet material of Production Example 10.

[0030] An example of a preferred embodiment will be described in detail below. Each configuration and combination thereof in each embodiment is merely an example, and addition, omission, substitution, and other modifications of configurations are possible as appropriate within the scope of the present disclosure. The present disclosure is not limited by the embodiments, but only by the scope of the claims. Furthermore, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification.

[0031] In this disclosure, the range "X to Y" means "X or more and Y or less." Unless otherwise noted, all test temperatures are room temperature (20°C ± 5°C), and "wt%" means weight percent, not mass concentration. Furthermore, the unit of mass "t (ton)" means "metric ton."

[0032] [Laminated Material] The laminated material of the present disclosure includes a substrate and a sheet material laminated and integrated onto the surface of the substrate. For example, the laminated material of the present disclosure preferably includes a sheet material laminated and integrated so that the main surface of at least one surface of the substrate contacts the main surface of the surface of the sheet material. In the present disclosure, the surface with the largest contact area between the base and the sheet material is referred to as the "main surface." The number of substrates and sheet materials included in the laminated material is not particularly limited, and multiple substrates and sheet materials may be alternately laminated and integrated. In other words, the laminated material of the present disclosure has a layered structure composed of substrates and sheet materials. For example, the laminated material may include a first substrate and a sheet material laminated and integrated onto the surface of the first substrate, or may include a first substrate and a second substrate laminated and bonded to the first substrate via the sheet material.

[0033] In this disclosure, for convenience, in an embodiment in which substrates are bonded to both sides of a sheet material, one will be referred to as a "first substrate" and the other will be referred to as a "second substrate," and the laminated material of the present disclosure is not limited to a two-layer structure or a three-layer structure. The laminated material may include layers other than the sheet material and the substrates as long as the effects of the present disclosure can be obtained.

[0034] Here, "sheet material" means a thin, flat member, and is a concept that includes so-called sheets and films. Furthermore, "laminated and integrated" does not simply mean a state in which a substrate and a sheet material are overlapped, but means a state in which the sheet material is firmly adhered to the surface of the substrate. As long as the sheet material and the substrate are firmly adhered, the interface between the substrate and the sheet material may be clear or unclear. "Laminated adhesion" means a state in which a first substrate and a second substrate are firmly adhered (i.e., integrated) via a sheet material.

[0035] As described below, this laminated material is produced by heat-pressing a substrate and a sheet material together without using chemicals such as adhesives. As described below, the sheet material is formed by removing liquid components from a plant solution obtained by dissolving a plant material in an organic acid. Since the organic acid is removed as a liquid component, this sheet material is formed substantially from plant-derived components only. For example, when a plant material is used as the substrate, a laminated material substantially consisting of plant-derived components and plant material is obtained.

[0036] In the present disclosure, "substantially" means, for example, that the content of plant-derived components in the sheet material is 90% by weight or more, preferably 95% by weight or more, and ideally 100% by weight. When a plant material is used as the substrate, the total content of the plant material and plant-derived components in the laminated material is 90% by weight or more, preferably 95% by weight or more, and ideally 100% by weight. In this case, the laminated material can be said to be 100% plant material.

[0037] While the present disclosure provides a laminated material made entirely from plant materials, the sheet material or laminated material may contain plant-derived components and components other than plant materials, as long as the effects of the present disclosure are not impaired. For example, to impart desired functionality to the laminated material, the sheet material may contain known additives. Examples of such additives include conductive agents, magnetic powders, antibacterial agents, flame retardants, antioxidants, and ultraviolet absorbers.

[0038] Adding a conductive agent to a sheet material can suppress static buildup and reduce electrostatic discharge during dry periods. Adding magnetic powder to a sheet material can produce a laminate that can be attached and fixed with a magnet, or a laminate that can block electromagnetic waves emitted from the sun, electronic devices, etc. Adding an antibacterial agent to a sheet material can produce a laminate that can be used in the sanitary and toiletry fields and hygienic material applications where antibacterial and antiviral properties are required. Furthermore, adding an antibacterial agent can suppress biodegradation of the laminate material itself and changes in appearance due to bacterial growth. Adding a flame retardant to a sheet material can be used in the construction field where fire resistance and other properties are required. Adding an antioxidant or ultraviolet absorber to a sheet material can be used in the construction field where weather resistance and light resistance are required.

[0039] According to the present disclosure, a laminated material made from 100% plant materials can be obtained, but the sheet material or laminated material may contain divalent or higher fatty acids and / or their anhydrides as components other than plant-derived components and plant materials. When it is desired to obtain a glossier appearance while surface-modifying the laminated material, and / or when it is desired to integrate the substrate and the sheet material under milder conditions, it is preferable that the sheet material contain divalent or higher fatty acids and / or their anhydrides. Of the organic acids mentioned above, divalent or higher fatty acids that are not completely removed as liquid components from the plant solution are preferred. Specific divalent or higher fatty acids are described in detail in the [Sheet Material] section.

[0040] [Substrate] Hereinafter, descriptions regarding "substrate" can be interpreted as descriptions regarding "first substrate" and "second substrate".

[0041] The material of the substrate is not particularly limited as long as it is firmly bonded to the sheet material. The materials of the first substrate and the second substrate may be the same or different. As described below, the sheet material of the present disclosure contains a plant-derived component in which some or all of the hydroxyl groups have been formylated. Formylated plant-derived components, such as lignin and hemicellulose, are hydrophobic, and therefore are thought to be activated by heating to exhibit strong adhesive properties even if the substrate material is lipophilic. For example, the substrate material may be selected from the group consisting of biomass materials, plastics, metals, ceramics, glass, pulp molds, and paper. If necessary, the surface of the substrate may be corona-treated.

[0042] In the present disclosure, the type of plastic used for the substrate is not particularly limited. For example, polyethylene, polypropylene, ABS (acrylonitrile butadiene styrene copolymer), polystyrene, polymethyl methacrylate, polylactic acid, PEEK (polyether ether ketone resin), polycarbonate, polyurethane, polyester, PET (polyethylene phthalate), LCP (liquid crystal polymer), etc. can be used. The plastic may be a foam. Polyethylene is preferably used.

[0043] In the present disclosure, the metal used for the substrate may be iron, stainless steel, nickel, copper, silver, gold, aluminum, tinplate, etc. Furthermore, the ceramic may be pottery such as earthenware.

[0044] From the viewpoint of obtaining a laminated material made from plant materials, preferred substrate materials are paper, pulp mold, and biomass materials. Paper may be kraft paper, hardwood pulp (LBKP), or softwood pulp (NBKP). Softwood pulp (NBKP) is thin but strong, tear-resistant, and has high strength, making it suitable for a wide range of applications. In terms of the relationship between desired strength and cost, hardwood pulp (LBKP) or a mixture of hardwood pulp (LBKP) and softwood pulp (NBKP) may be used.

[0045] The pulp mold may be a thick wall mold with a thickness of 5 to 10 mm, a thermoformed mold, a Pulp Injection Mold (PIM), or a Pulp Foaming Mold (PF), and can be selected appropriately depending on, for example, the desired load-bearing capacity. A thick wall mold is preferably used from the viewpoint of obtaining a substrate with a thick film thickness and high load-bearing capacity. In the case of a thick wall mold, the pulp material adsorbed and laminated on the shaping mold can be dried and solidified as is without press molding. In this case, the sheet material of the present disclosure can be bonded to the smooth surface adsorbed on the shaping mold. This results in a pulp mold with a modified surface.

[0046] PIM is a technology for molding pulp by injection molding. Complex pulp mold structures, including interlocking structures, bosses, and ribs, can be obtained as the substrate. In this case, the sheet material of the present disclosure is placed in a mold in advance, and pulp fibers containing starch as a binder are injected into the molding machine as the substrate raw material. Specifically, after the substrate raw material is filled into the mold containing the sheet material, the mold repeatedly opens and closes delicately to remove moisture from the substrate raw material and dry it, while the sheet material is heated. After the substrate raw material is dried, the mold is cooled and the solidified molded product is removed, resulting in a surface-modified pulp mold. Furthermore, the substrate used in this disclosure may be a foam product obtained by extrusion molding a mixture of paper powder, industrial starch, and synthetic resin, foamed with steam, and then extruded. This foam product has environmental advantages over other plastic foams and can be used in the same way as existing plastic foam products. By modifying the surface of a molded article made from this foam product with the sheet material of the present disclosure, it is possible to impart a more desirable appearance and feel to the molded article of a desired shape.

[0047] The biomass material may be woody biomass, herbaceous biomass, or a mixture thereof. Examples of herbaceous biomass include sugarcane bagasse, rice straw, wheat, bran, tomato, onion, and moso bamboo.

[0048] A typical example of woody biomass is wood. The type of wood is not particularly limited, and may be a broadleaf tree or a conifer. Furthermore, the part of the wood is also not particularly limited, and may be any of heartwood, sapwood, and transitional wood. It may also be a part with knots, black streaks, discoloration, or the like, or a part with a rough texture and lacking in aesthetic appeal. According to the present disclosure, even if the material of the substrate is a low-grade wood with an appearance that is not normally used as an exterior material, it is possible to produce a laminated material with a beautiful and luxurious appearance by laminating and integrating sheet materials.

[0049] Wood boards or laminated lumber may be used as substrates to the extent that the effects of the present disclosure are not impaired. Conventionally, wood boards are materials made by mixing small pieces of wood with adhesives such as urea-melamine resins or modified phenolic resins and then thermocompressing them. Laminated lumber is a material made by bonding small pieces of wood together with adhesives such as resorcinol resins or aqueous polymeric isocyanate-based adhesives. However, wood boards or laminated lumber made using the adhesives described below are preferably used as substrates in the present disclosure. For example, in wood boards obtained using a "plant solution in which plant materials are dissolved in organic acids" as an adhesive, the organic acids are thought to evaporate when heated during bonding. Furthermore, as described below, the adhesives of the present disclosure contain plant-derived components, such as lignocellulose, in which some or all of the hydroxyl groups have been formylated. Even if some of this formylated lignocellulose decomposes, the products are formic acid, lignin, cellulose, and hemicellulose, which do not adversely affect the natural environment. In the case of such a substrate, the chips (sawdust in the case of wood) do not contain adhesives as so-called chemicals, and therefore, when disposed of, they can be safely disposed of by landfill or incineration.

[0050] The raw materials for wood boards and laminated lumber are mainly small pieces cut and shredded from demolition waste, thinned wood, etc. Although fine cutting causes the original properties of raw wood to be lost, reducing resistance and making it more susceptible to mold, these problems are alleviated by laminating and integrating the sheet material of the present disclosure. Laminated materials using wood boards or laminated lumber as a base material and including sheet materials laminated and integrated onto this base material have excellent durability. In particular, laminated materials using wood boards or laminated lumber as a base material obtained using the adhesive of the present disclosure are made from 100% plant materials and are highly biodegradable. The herbaceous biomass described above can also be used as a raw material for wood boards and laminated lumber.

[0051] The type of wood board is not particularly limited. For example, fiberboard obtained by molding fibrous wood chips, particleboard obtained by molding chip-like wood chips, oriented strand board (OSB), parallel strand lumber (PSL), oriented strand lumber (OSL), etc. can be appropriately selected. The fiberboard may be medium-density fiberboard (MDF), hardboard, or softboard (insulation board).

[0052] The type of laminated lumber is not particularly limited. In terms of classification based on joining method, any of scarf joint, finger joint, and pad joint is acceptable. Finger joints, which have high adhesive strength, are preferred. Cross-laminated timber (CLT), laminated veneer lumber (LVL), and plywood are also acceptable. Examples of raw material tree species include Douglas fir, European red pine (redwood), SPF (spruce, pine, and fir), American cypress, American larch, Japanese cedar, and larch.

[0053] [Sheet Material] The sheet material has an infrared absorption spectrum of 1715 to 1725 cm －１ It shows an absorption peak with a peak top in the region of wavenumber 1715 to 1725 cm －１The absorption at 1715 to 1725 cm occurs due to the C═O stretching vibration. Specifically, it is an absorption peak due to the C═O stretching vibration of the aldehyde group (formyl group). －１ The presence of this absorption peak indicates that some or all of the hydroxyl groups of the cellulose, hemicellulose, and lignin contained in the sheet material as plant-derived components are formylated. The presence of this absorption peak distinguishes the sheet material of the present disclosure from materials simply cut into sheets from wood or materials formed into sheets by accumulating wood flour or the like.

[0054] In the infrared absorption spectrum of the sheet material, the peak intensity (peak height) caused by the C═O stretching vibration is 1000 cm －１ ~1200cm －１ The peak intensity of the C═O stretching vibration is preferably 5% or more, more preferably 15% or more, and particularly preferably 30% or more higher than the peak intensity of cellulose occurring in the region of C═O stretching vibration. This is because the higher the peak intensity due to the C═O stretching vibration, the higher the degree of formylation, and the formylated plant-derived component is thought to contribute to improving the adhesive strength of the sheet material to the substrate.

[0055] The infrared absorption spectrum of the sheet material shows the OH stretching vibrations of cellulose and hemicellulose (3200 to 3600 cm －１ around 2840-3000 cm), CH stretching vibration of cellulose, hemicellulose and lignin －１ around 1600 cm), skeletal vibration of lignin benzene ring ( －１ around 1060 cm), C-O stretching vibration of cellulose and hemicellulose －１ The compound may further have any or all of the absorption peaks such as those around 1000 nm (near 1000 nm).

[0056] The sheet material is substantially composed of plant-derived components. The type of plant is not particularly limited, but may be, for example, wood such as coniferous trees (such as cedar, cypress, and red pine), broad-leaved trees (such as eucalyptus and beech), or herbaceous plants such as rice, sugarcane, wheat, tomato, onion, and moso bamboo. From the viewpoint that a luxurious appearance can be obtained even when the base material is low-quality wood, a sheet material composed of components derived from so-called high-quality wood such as cedar or cypress is preferred.

[0057] In the present disclosure, the plant-derived component may be one or more selected from the group consisting of cellulose, hemicellulose, and lignin. The plant-derived component may contain all of cellulose, hemicellulose, and lignin, or may contain these in the form of lignocellulose. Here, the form of lignocellulose refers to a form in which cellulose, hemicellulose, and lignin are intricately entangled to form a higher-order structure. More specifically, this refers to a form in which cellulose, a linear polymer, forms a crystalline structure through intramolecular and intermolecular hydrogen bonds to form strong microfibrils (cellulose microfibrils), which are entangled with hemicelluloses such as xylan and glucomannan, and further, lignin, an irregular aromatic polymer, fills the voids in the matrix of these polysaccharides.

[0058] As long as the effects of the present disclosure are obtained, the total content of cellulose, hemicellulose, and lignin (or the content as lignocellulose) in the sheet material is not particularly limited. From the viewpoint of imparting an appearance similar to that of natural wood, the total content of cellulose, hemicellulose, and lignin may be 90% by weight or more, 95% by weight or more, 98% by weight or more, or 100% by weight. Some or all of the hydroxyl groups of this cellulose, hemicellulose, and lignin may be formylated.

[0059] The total content of hemicellulose and lignin in the sheet material is not particularly limited. From the viewpoint of improving adhesion to the substrate and increasing pencil hardness, the total content of hemicellulose and lignin may be 5% by weight or more, 10% by weight or more, or 15% by weight or more.

[0060] The sheet material may contain a plant-derived fibrous material. By laminating and integrating the sheet material containing the fibrous material onto a substrate, a laminated material with excellent durability can be obtained. The presence of this fibrous material can be confirmed by observation with a scanning electron microscope.

[0061] The fibrous material in the sheet material may be the aforementioned cellulose microfibrils. For example, the fibrous material may be cellulose fibers that were not completely dissolved during the sheet material manufacturing process. This fibrous material may have a cellulose type I crystalline structure. The presence of the cellulose type I crystalline structure can be confirmed by X-ray diffraction measurement. For example, a sample of a sheet material collected from a laminate and freeze-dried can be measured using an X-ray diffraction measurement device (e.g., Rigaku's "SmartLab"). Specifically, measurement can be performed by powder X-ray diffraction using a non-reflective silicon plate. Cellulose type I crystals with a parallel chain structure have been found to exhibit high-intensity diffraction peaks around 2θ = 22.5° and, by peak separation, around 16.7° and 14.8°. Therefore, the presence or absence of a cellulose type I crystalline structure can be determined by confirming the presence or absence of high-intensity diffraction peaks around 2θ = 22.5°, 16.7°, and 14.8° in an X-ray diffraction diagram measured on a sample collected from a wood-based molded product.

[0062] According to the present disclosure, a sheet material made from 100% plant materials can be obtained, but the sheet material may also contain divalent or higher fatty acids and / or their anhydrides as components other than plant-derived components and plant materials. When it is desired to obtain a glossier appearance while surface-modifying the laminated material, and / or when it is desired to integrate the substrate and the sheet material under milder conditions, it is preferable for the sheet material to contain divalent or higher fatty acids and / or their anhydrides. The excellent effects achieved by including divalent or higher fatty acids and / or their anhydrides in the sheet material are thought to be due to the interaction between the plant-derived components and plant materials in the sheet material and the divalent or higher fatty acids and / or their anhydrides.

[0063] More specifically, the sheet material of the present disclosure has a thickness of 1715 to 1725 cm －１Some or all of the hydroxyl groups of the cellulose, hemicellulose, and lignin contained as plant-derived components have been formylated, and the cellular structure of wood has been disassembled, so that an absorption peak of 1000 nm is present. The sheet material or laminated material of the present disclosure, which contains such plant-derived components and plant materials and also contains divalent or higher fatty acids and / or anhydrides thereof, is essentially different from a molded product obtained by simply blending wood flour, wood, wood chips, etc. with divalent or higher fatty acids and / or anhydrides thereof and heat treating the mixture.

[0064] When a divalent or higher fatty acid and / or anhydride thereof is contained in the sheet material, the ductility and adhesive strength (adhesiveness) of the sheet material are also improved.

[0065] In this specification, divalent or higher fatty acids are also referred to as polycarboxylic acids. Furthermore, in this specification, "and / or" is used to mean both "and" and "or." For example, divalent or higher fatty acids and / or their anhydrides include (i) divalent or higher fatty acids, (ii) anhydrides of divalent or higher fatty acids, and (iii) divalent or higher fatty acids and anhydrides of divalent or higher fatty acids, and are the same as "at least one selected from the group consisting of divalent or higher fatty acids and anhydrides of divalent or higher fatty acids."

[0066] Examples of divalent or higher fatty acids include succinic acid, adipic acid, malic acid, tartaric acid, malonic acid, fumaric acid, maleic acid, oxalic acid, phthalic acid, isophthalic acid, terephthalic acid, 2,6-pyridinedicarboxylic acid, acetonedicarboxylic acid, 3-oxoglutaric acid, 2,3-naphthalenedicarboxylic acid, azelaic acid, hexadecanedioic acid, docosanedioic acid, α,ω-alkanedicarboxylic acids, citric acid, and 1,2,3,4-butanetetracarboxylic acid. Examples of divalent or higher fatty acids include polysaccharide polycarboxylic acids. Examples of polysaccharide polycarboxylic acids include polyuronic acids such as alginic acid and pectin; polyuronic acids obtained by oxidizing the primary hydroxyl groups of cellulose; and carboxymethyl cellulose. The divalent or higher fatty acids and / or anhydrides thereof may be used alone or in combination of two or more. The divalent or higher fatty acid and / or anhydride thereof is preferably citric acid and / or anhydride thereof.

[0067] When the sheet material contains a divalent or higher fatty acid and / or anhydride thereof, the content thereof is preferably 3 to 200 parts by weight, more preferably 15 to 150 parts by weight, even more preferably 20 to 100 parts by weight, and particularly preferably 25 to 75 parts by weight, relative to 100 parts by weight of the total of the plant-derived components and plant materials that make up the sheet material. When a divalent or higher fatty acid and / or anhydride thereof is contained, it is preferable that the constituent components excluding said components consist essentially of plant-derived components and plant materials.

[0068] The sheet material may contain hydroxy acids and / or ammonium dihydrogen phosphate as components other than plant-derived components and plant materials. Here, hydroxy acids encompass carboxylic acids and alcohols. Specific examples of hydroxy acids include glycolic acid, lactic acid, glyceric acid, hydroxybutyric acid, citramalic acid, isocitric acid, leucinic acid, mevalonic acid, pantoic acid, ricinoleic acid, ricinelaic acid, cerebronic acid, quinic acid, and shikimic acid.

[0069] The components that may be contained in the sheet material, i.e., at least one selected from the group consisting of divalent or higher fatty acids, divalent or higher fatty acid anhydrides, hydroxy acids, and ammonium dihydrogen phosphate, are considered to function as a crosslinking agent. Here, the crosslinking agent refers to an agent that crosslinks lignocellulose molecules. When the sheet material of the present disclosure contains at least one selected from the group consisting of divalent or higher fatty acids, divalent or higher fatty acid anhydrides, hydroxy acids, and ammonium dihydrogen phosphate, a crosslinked structure formed by covalent bonds may be formed in the sheet material of the present disclosure.

[0070] When the sheet material of the present disclosure contains divalent or higher fatty acids and / or anhydrides thereof, polyhydric alcohols and / or sugars may be used together with the divalent or higher fatty acids and / or anhydrides thereof. Examples of polyhydric alcohols and sugars include glycerin, ethylene glycol, sucrose, starch, chitin, chitosan, cellulose, dextran, pullulan, β-1,3 glucan, β-1,6 glucan, glucose, cellooligosaccharides, mannose, mannooligosaccharides, xylose, xylooligosaccharides, amino acids, peptides, proteins, etc.

[0071] Furthermore, as described above, the present disclosure provides a laminated material made from 100% plant materials. However, the sheet material or laminated material may contain components other than plant-derived components and plant materials (e.g., additives such as conductive agents, magnetic powders, antibacterial agents, flame retardants, antioxidants, and UV absorbers) to the extent that the effects of the present disclosure are not impaired. When the sheet material contains additives, the content of the additives is preferably 1 to 500 parts by weight, more preferably 3 to 100 parts by weight, and even more preferably 5 to 75 parts by weight, per 100 parts by weight of the total of the plant-derived components and plant materials that make up the sheet material. When the sheet material contains additives, it is preferable that the components excluding the additives consist essentially of plant-derived components and plant materials.

[0072] The sheet material of the present disclosure can be used in the laminated material described above. The density of this sheet material is not particularly limited and can be adjusted by the type of raw material, dissolution conditions, etc. For example, the density of the sheet material can be 0.2 g / cm ３ or more, and３ or more, and ３ or more, and ３ or more, and 1.2 g / cm ３ or less, and ３ or less, and ３ The density of the sheet material is an apparent density measured in accordance with JIS Z 8807 "Method for measuring density and specific gravity of solids."

[0073] The tensile properties of the sheet material are appropriately set depending on the application of the laminate, etc., but from the viewpoint of ease of formability, the Young's modulus of this sheet material may be 0.05 GPa or more, or 1.0 GPa or more. From the viewpoint of durability, the preferred Young's modulus is 4.0 GPa or less. From the viewpoint of durability, the maximum stress of the sheet material may be 0.5 MPa or more, 5.0 MPa or more, or 10 MPa or more. From the viewpoint of ease of formability, the preferred maximum stress is 80 MPa or less. From the viewpoint of ease of formability, the maximum elongation of the sheet material may be 0.5% or more, or 1.5% or more. From the viewpoint of durability, the preferred maximum elongation is 5.0% or less. The Young's modulus, maximum stress, and maximum elongation of the sheet material are measured by a tensile test in accordance with the provisions of ISO 527-1. Details of the measurement method and measurement conditions will be described later in the examples.

[0074] The thickness of the sheet material is appropriately set depending on the application of the laminate material, and is not particularly limited. The thickness of the sheet material may be thinned as long as the effects of improving the appearance of the substrate, making the surface hydrophobic, and increasing the pencil hardness are achieved. For example, the average thickness of the sheet material may be 2 mm or less, 500 μm or less, or 50 μm or less. Using a thinner sheet material reduces the amount of plant resources used as the raw material for the sheet material, and allows for the production of a laminate material that reflects the physical properties of the substrate itself (e.g., hardness and wood grain). On the other hand, when a wood board or the like is used as the substrate, a thicker sheet material can be used for surface modification, such as decoration. The average thickness of the sheet material in the present disclosure is the average value of measurements taken multiple times using known means.

[0075] From the viewpoint of obtaining high heat resistance, the glass transition temperature Tg of the sheet material may be 180°C or higher, 190°C or higher, or 200°C or higher. Although there is no particular upper limit, the glass transition temperature Tg is preferably 280°C or lower. The glass transition temperature of the sheet material is measured by dynamic viscoelasticity measurement. Details of the measurement method and measurement conditions will be described later in the examples.

[0076] The sheet material of the present disclosure preferably has a homogeneous color pattern with few patterns. In a laminated material obtained by laminating such a sheet material to, for example, a wood substrate, the grain of the wood substrate is visible through the sheet material, allowing the material to maintain an appearance similar to that of the substrate. Furthermore, when laminated wood is used as the substrate, the joints of the laminated wood are covered and concealed by the sheet material, resulting in a good appearance. On the other hand, wood sheets made by simply slicing wood thinly may retain their grain, and when these are bonded to the wood substrate with an adhesive or the like, the grain of the sheet and the grain of the substrate may become intertwined, resulting in a poor appearance.

[0077] [Method for manufacturing laminated material] The method for manufacturing a laminated material disclosed herein includes: (1) dissolving a plant raw material in an organic acid to obtain a plant solution (dissolution step); (2) removing liquid components from the obtained plant solution to obtain a sheet material formed substantially from plant-derived components (sheet formation step); and (3) laminating the sheet material on the surface of a first substrate and heat-pressing the sheet material to obtain a laminated material in which the sheet material and the first substrate are integrated (lamination step 1).

[0078] The laminated material of the present disclosure may be obtained by a manufacturing method including: (1) dissolving a plant raw material in an organic acid to obtain a plant solution (dissolution step); (2) removing liquid components from the obtained plant solution to obtain a sheet material formed substantially from plant-derived components (sheet formation step); and (3) placing a sheet material between the first substrate and the second substrate and heat-pressing the sheet material to laminate and bond the first substrate and the second substrate together (lamination step 2).

[0079] In this manufacturing method, a laminated material is produced by removing liquid components containing organic acid from a plant solution prepared by dissolving plant materials in organic acid, and then placing the resulting sheet material in contact with the surface of the aforementioned substrate and laminating and adhering the sheet material. Because the organic acid used to dissolve the plant materials is removed as a liquid component, a sheet material consisting essentially of plant-derived components is obtained. Therefore, the sheet material of the present disclosure is made entirely from plant materials, free of residual organic solvents and other chemicals that contribute to sick building syndrome. Furthermore, the sheet material and the substrate are integrated by thermocompression bonding without the use of adhesives or the like. For example, when wood is selected as the substrate material, this manufacturing method can produce a laminated material made entirely from plant materials, free of residual chemicals derived from adhesives. This manufacturing method uses minimal chemicals in each process, and in particular, does not require the use of highly volatile organic solvents. This manufacturing method also offers excellent safety during operation.

[0080] Furthermore, with the manufacturing method of the present disclosure, even if the substrate material is so-called low-grade wood or wood whose aesthetics have been impaired by aging or the like, it is possible to impart an excellent appearance by laminating and integrating the sheet material of the present disclosure. Furthermore, since wood flour, chips, etc. can be used as plant raw materials for the sheet material, for example, by effectively utilizing wood flour, etc. generated during the sawing of high-quality wood, it is possible to obtain a laminated material with a luxurious appearance. In addition, biomass resources such as building waste, thinned wood, unused crops, and agricultural waste can be effectively utilized as plant raw materials for the sheet material.

[0081] Each step will be described in detail below.

[0082] (1) Dissolution Step In this step, a plant material is first dissolved in an organic acid to obtain a plant solution. The plant material is not particularly limited and may be woody biomass, herbaceous biomass, or a mixture thereof.

[0083] The woody biomass may be coniferous (such as cedar, cypress, or red pine) or broad-leaved (such as eucalyptus or beech). Two or more types may be used in combination. From the viewpoint of effective utilization of dwindling forest resources, woody biomass that has traditionally been discarded can be suitably used. For example, wood flour generated during sawing, small pieces (chips) that cannot be used as scraps, etc. may be used as plant raw materials. From the viewpoint of imparting a luxurious appearance to the laminated material, so-called high-quality woods such as cedar and cypress are preferred. According to the method of the present disclosure, wood flour, chips, etc. generated during sawing of high-quality woods can be effectively utilized as plant raw materials.

[0084] The woody biomass may be natural wood or a lumber product cut from natural wood. The shape of the woody biomass is not particularly limited, and may be selected appropriately from, for example, a plate, chip, powder, or the like.

[0085] Examples of herbaceous biomass include sugarcane bagasse, rice straw, wheat, bran, tomato, onion, moso bamboo, etc. Two or more of these may be used in combination.

[0086] Woody biomass or herbaceous biomass may be pulverized before use, if necessary. From the viewpoint of improving dissolution efficiency, the size of the plant raw material may be such that the maximum diameter in a plan view is 50 mm or less, 40 mm or less, or 30 mm or less. From the viewpoint of preventing dust, the size of the plant raw material is preferably such that the maximum diameter in a plan view is 0.1 mm or more. If necessary, the plant raw material may be pulverized to the aforementioned size before being mixed with the organic acid.

[0087] The type of organic acid is not particularly limited, but a typical organic acid is a carboxylic acid. It may be an aliphatic carboxylic acid or an aromatic carboxylic acid. From the viewpoint of excellent solubility of plant raw materials, α-keto acids and carboxylic acids having a formyl group are preferred, and organic acids selected from the group consisting of formic acid, glyoxylic acid, and pyruvic acid are particularly preferred. Formic acid, which can be produced using wood gas (a mixed gas of carbon dioxide and hydrogen) as a raw material, is particularly preferred.

[0088] Here, "dissolved" refers to a state in which the shape of the plant material added to the organic acid cannot be recognized with the naked eye. Even when fibrous materials derived from lignocellulose are observed in the plant material by microscopic observation or the like, the state is defined as "dissolved" if the shape of the plant material itself has disappeared. In this disclosure, a liquid in such a "dissolved" state is defined as a "solution," and a solution containing plant-derived components is referred to as a "plant solution." Although it is preferable that the plant material is uniformly dissolved in the organic acid, the plant material may also be partially dissolved in the organic acid. In the case of partial dissolution, the plant solution may be obtained by removing the insoluble portion by filtration or the like.

[0089] The amount of organic acid to be mixed with the plant raw material is appropriately selected depending on the type and shape of the plant raw material, the type of organic acid, etc. From the viewpoint of improving dissolution efficiency, the amount of organic acid may be 4 parts by weight or more, or 9 parts by weight or more, per 1 part by weight of the plant raw material. From the viewpoint of improving production efficiency, the amount of organic acid may be 200 parts by weight or less, 100 parts by weight or less, or 50 parts by weight or less, per 1 part by weight of the plant raw material. As long as the effects of the present disclosure are obtained, the organic acid may be added to the cellulose-containing raw material as is, or may be added to the cellulose-containing raw material as a solution of the desired concentration.

[0090] As long as a plant solution can be obtained, the dissolution conditions are not particularly limited and are appropriately selected depending on the type and shape of the plant raw material, the type of organic acid, etc. For example, from the viewpoint of high dissolution efficiency, the dissolution temperature may be 20°C or higher, 30°C or higher, or 40°C or higher. From the viewpoint of energy reduction, the dissolution temperature may be 100°C or lower, 90°C or lower, or 80°C or lower. The dissolution time can be appropriately set depending on the dissolution temperature.

[0091] To promote dissolution, the plant raw material may be stirred after being added to the organic acid, or may be stirred with pulverization. Stirring with pulverization in the organic acid allows the plant raw material to be dissolved under milder conditions. Examples of devices for stirring with pulverization include a bead mill, a colloid mill, a disc refiner, and a conical refiner.

[0092] From the viewpoint of promoting dissolution, pressure or vacuum treatment may be performed using a pressure adjustment means before and / or after mixing the plant material with the organic acid. It is believed that the pressure fluctuations applied to the plant material by the pressure adjustment means relax the rigid higher-order structure of cellulose, particularly lignocellulose, in the plant material, improving its solubility in organic acid. By performing pressure or vacuum treatment, dissolution at a relatively low temperature becomes possible, reducing the energy required for heating and / or keeping warm during dissolution. From the viewpoint of efficiently introducing the organic acid into the tissue of the plant material by the pressure fluctuations, it is preferable to pressurize or vacuum the plant material after adding the organic acid.

[0093] When reducing the pressure, it is preferable to reduce the pressure in the range of 1.0 kPa to 10.0 kPa (absolute pressure). When increasing the pressure, it is preferable to increase the pressure in the range of 200 kPa to 1000 kPa (gauge pressure). In this specification, absolute pressure is used when a pressure lower than atmospheric pressure is indicated by a reduction treatment, and gauge pressure based on atmospheric pressure is used when a pressure higher than atmospheric pressure is indicated by a pressurization treatment.

[0094] The pressure adjusting means used for the pressurized or reduced pressure treatment is not particularly limited, and may be adjusted to the above-mentioned pressure range by known means such as an aspirator, an ejector, a compressor, or a mechanical pump.

[0095] The solids concentration of the plant solution obtained by dissolving plant raw materials in an organic acid is not particularly limited, but from the viewpoint of facilitating removal of liquid components, the solids concentration of the plant solution may be 0.5 (w / v)% or more, 1.0 (w / v)% or more, 1.5 (w / v)% or more, or 2.0 (w / v)% or more. From the viewpoint of ease of production, the solids concentration of the plant solution may be 20 (w / v)% or less, 15 (w / v)% or less, or 10 (w / v)% or less. The plant solution may further contain known additives such as pigments, as long as the effects of the present disclosure are not impaired.

[0096] (2) Sheet Formation Step In this step, the liquid component is removed from the plant solution to recover the solid component, which is then formed into a sheet to obtain the sheet material of the present disclosure, which is substantially made from plant-derived components.

[0097] The method for removing the liquid component from the plant solution to obtain the sheet material is not particularly limited. For example, the sheet material of the present disclosure may be obtained by casting the plant solution into a container of a desired size and shape and drying it to remove the liquid component, or by forming the dried solid into a sheet. Furthermore, to improve drying efficiency, the plant solution may be concentrated before drying using known concentration methods such as evaporation and vacuum concentration. Water or alkali may be added to the plant solution as a precipitant, as long as the effects of the present disclosure are obtained. The sheet material of the present disclosure may be obtained by forming the solid precipitated by adding water or alkali into a sheet and drying it. Since methods using a precipitant may result in the loss of some of the components contained in the plant material, casting methods are preferred.

[0098] The organic acid added during dissolution has been removed as a liquid component from the sheet material obtained in this manner. This sheet material is a regenerated solid content of the dissolved plant raw material, and is formed substantially only from plant-derived components.

[0099] The plant-derived component mainly contains cellulose. The plant-derived component may contain lignin and hemicellulose together with cellulose. Preferably, the plant-derived component contains one or more selected from the group consisting of cellulose, hemicellulose, and lignin. Some or all of the hydroxyl groups of the cellulose, hemicellulose, and lignin may be formylated. The plant-derived component may further contain polyphenols such as tannin, catechin, and flavonoids, terpenes, and the like.

[0100] Furthermore, the sheet material or solid matter obtained by removing the liquid component from the plant solution may be washed to further remove organic acid-derived components, alkali-derived components, etc. Distilled water can be used for washing.

[0101] As long as the effects of the present disclosure are obtained, the thickness of the resulting sheet material is not particularly limited and can be adjusted, for example, by the solids concentration of the plant solution. From the viewpoint of being able to conceal the appearance of the substrate surface, the average thickness of the sheet material may be 10 μm or more, 100 μm or more, or 200 μm or more. From the viewpoint of being easily integrated with the substrate, the average thickness of the sheet material may be 2000 μm or less, 1000 μm or less, 800 μm or less, or 600 μm or less. Note that the "average thickness" described here refers to the average thickness of the sheet material before being heat-pressed and bonded to the substrate, and is the average value of measurements taken multiple times using known means.

[0102] (3) Lamination Process This process is a process for obtaining a laminated material from the aforementioned sheet material and substrate. Specifically, the sheet material is laminated on the substrate and then heat-pressurized. More specifically, this process may be a process for obtaining a laminated material in which the sheet material and the first substrate are integrated by laminating the sheet material so that the surface of the sheet material contacts the surface of the first substrate and then heat-pressurizing the first substrate and the second substrate. Alternatively, this process may be a process for laminating and adhering the first substrate and the second substrate by placing a sheet material between the first substrate and the second substrate and then heat-pressurizing the first and second substrates together. Furthermore, this process may be a process for laminating and adhering the first substrate and the second substrate together by laminating a sheet material on the surface of the first substrate and then heat-pressurizing the first substrate and the second substrate, and then laminating and adhering the second substrate to the surface of the sheet material integrated with the first substrate. According to the sheet material of the present disclosure, a laminated material in which the substrate and the sheet material are integrated can be obtained without using an adhesive or the like.

[0103] The material of the substrate is selected from the group consisting of wood, plastic, metal, ceramic, pulp mold, and paper. The above-mentioned types of substrates may be appropriately selected and used. The materials of the first substrate and the second substrate may be the same or different.

[0104] According to the present disclosure, even low-quality wood that has conventionally had problems with appearance can be suitably used as a substrate. There are no particular limitations on the shape and size of the substrate, but a shape with a substantially flat surface can be suitably used from the viewpoint of adhesion to the sheet material. From the viewpoint of obtaining a laminated material of plant materials, wood, pulp mold, and paper are preferred as the substrate, wood is more preferred, and sawn natural wood is even more preferred. However, wood boards, laminated lumber, plywood, etc. can also be used as long as they do not contain residual organic solvents, adhesives, etc. Wood boards, laminated lumber, plywood, etc. obtained using the adhesive of the present disclosure described below are more preferred.

[0105] A known heat press or the like can be used for thermocompression bonding of the sheet material and the substrate. The thermocompression conditions are appropriately set depending on the type and size of the sheet material and the substrate. From the viewpoint of facilitating lamination and integration of the sheet material and the substrate, the thermocompression temperature may be 60°C or higher, 80°C or higher, 100°C or higher, or 150°C or higher. From the viewpoint of avoiding discoloration and deformation of the sheet material and the substrate, the thermocompression temperature may be 220°C or lower, 200°C or lower, or 190°C or lower.

[0106] When the sheet material contains a divalent or higher fatty acid and / or anhydride thereof, the temperature for the thermocompression bonding may be 20° C. or higher, preferably 30° C. or higher, and more preferably 70° C. or higher. When the sheet material contains a divalent or higher fatty acid and / or anhydride thereof, the temperature for the thermocompression bonding may be 220° C. or lower, preferably 130° C. or lower, and more preferably 110° C. or lower. In this way, a sheet material containing a divalent or higher fatty acid and / or anhydride thereof can be integrated with a substrate under milder conditions than a sheet material not containing a divalent or higher fatty acid and / or anhydride thereof.

[0107] From the viewpoint of facilitating lamination and integration of the sheet material and the substrate, the pressure of thermocompression bonding may be 1 MPa or more, or may be 3 MPa or more. From the viewpoint of avoiding deformation of the sheet material and the substrate, the pressure of thermocompression bonding may be 15 MPa or less, and preferably 10 MPa or less. The time of thermocompression bonding is appropriately selected depending on the temperature and pressure. Here, the pressure during thermocompression bonding means the pressure applied to the sheet material on the substrate. The load (unit: N) applied to the heat press machine is multiplied by the area of ​​contact between the substrate and the sheet material (unit: m ２ ) to obtain the pressure (unit: Pa) during thermocompression bonding.

[0108] From the viewpoint of improving adhesion between the sheet material and the substrate, the surface of the substrate may be polished using a known polishing means before laminating the sheet material. In other words, this manufacturing method may include polishing the surface of the substrate before laminating the sheet material. For example, this manufacturing method may further include polishing the first substrate before laminating the sheet material, or may further include polishing the first substrate and the second substrate before placing the sheet material. As the polishing means, for example, various grades of abrasive paper can be used.

[0109] When preparing a sheet material containing divalent or higher fatty acids and / or their anhydrides, the timing of adding the divalent or higher fatty acids and / or their anhydrides may be any of the following: [i] A method in which the divalent or higher fatty acids and / or their anhydrides are mixed with the plant material and organic acid during the (1) dissolution step in which plant raw materials are dissolved in organic acid to obtain a plant solution; [ii] A method in which the divalent or higher fatty acids and / or their anhydrides are mixed after the (1) dissolution step in which plant raw materials are dissolved in organic acid to obtain a plant solution and before the (2) sheet formation step described above; or [iii] A method in which the divalent or higher fatty acids and / or their anhydrides are mixed after the (2) sheet formation step described above to prepare a sheet material that does not contain divalent or higher fatty acids and / or their anhydrides. In the case of the above-mentioned (iii), methods such as applying or impregnating the divalent or higher fatty acids and / or their anhydrides to a sheet material that does not contain divalent or higher fatty acids and / or their anhydrides may be used.

[0110] When various additives such as hydroxy acids, ammonium dihydrogen phosphate, polyhydric alcohols, sugars, and the above-mentioned additives are added to the sheet material, the timing of adding them is the same as when divalent or higher fatty acids and / or anhydrides thereof are added to the sheet material.

[0111] [Surface Modification Method for Molded Articles] The technology disclosed herein can be applied to the surface modification of molded articles made of various materials. This surface modification method includes (1) dissolving a plant material in an organic acid to obtain a plant solution (dissolving step), (2) removing liquid components from the obtained plant solution to obtain a sheet material formed substantially from plant-derived components (sheet forming step), and (3) laminating this sheet material onto the surface of a molded article and thermocompression bonding (surface modification step). This surface modification method can provide effects such as imparting a desired appearance to the molded article and improving durability by hydrophobizing the surface or increasing hardness. Furthermore, it can also be applied to a method for repairing and improving the appearance of wood molded articles whose appearance has deteriorated over time, etc. From the perspective of durability after surface modification, it is preferable that the sheet material be integrated with the molded article by thermocompression bonding.

[0112] The material of the molded product is not particularly limited as long as it can be thermocompressed with the sheet material of the present disclosure, but the materials described above for the substrate are preferably used. A molded product made of a material selected from the group consisting of wood, plastic, metal, ceramic, pulp mold, and paper is preferred. The molded product may be composed of a single member or a combination of multiple members. The materials of these components may be the same or different. It is preferred that the material of the component forming the surface of the molded product is selected from the group consisting of wood, plastic, metal, ceramic, pulp mold, and paper.

[0113] Here, "wooden molded product" refers to a molded product made primarily from wood. The components of a wooden molded product may be lumber or solid wood cut from natural wood, or may be plywood or laminated lumber made from multiple lumber pieces. If the appearance of a wooden molded product having such components on its surface is damaged by damage or deterioration over time, the good appearance of the wooden molded product can be restored by laminating the above-mentioned sheet material on the surface and repairing it by heat and pressure bonding.

[0114] Regarding this surface modification method, the details of the dissolving step and the sheet forming step are as described above. Regarding the surface modification step, the substrate in the lamination step described above can be replaced with a molded product. In the present disclosure, the surface modification step does not require the use of adhesives or the like. Even when this surface modification method is applied to building materials, furniture, etc., the occurrence of sick building syndrome due to residual adhesives or other chemicals can be avoided.

[0115] [Adhesive] As described above, substrates made of various materials are bonded together via the sheet material of the present disclosure. In other words, the sheet material of the present disclosure can be used as an adhesive for bonding components made of various materials. Furthermore, the plant solution described above can also be used to bond various components. That is, the adhesive of the present disclosure includes a plant solution obtained by dissolving a plant material in an organic acid, and / or a sheet material consisting essentially of plant-derived components obtained by removing the liquid components from the plant solution. From another perspective, the present disclosure provides a bonding method that includes adding to an object to be bonded a plant solution obtained by dissolving a plant material in an organic acid, and / or a sheet material consisting essentially of plant-derived components obtained by removing the liquid components from the plant solution, and heating the resulting material. The plant solution and sheet material contain plant-derived components in which some or all of the hydroxyl groups have been formylated. It is believed that the formylated plant-derived components act as an adhesive.

[0116] The adhesive of the present disclosure preferably comprises a plant solution obtained by dissolving a plant raw material in an organic acid, the plant solution comprising plant-derived components, the plant-derived components being one or more selected from the group consisting of cellulose, hemicellulose, and lignin, and some or all of the hydroxyl groups of the cellulose, hemicellulose, and lignin being formylated.

[0117] The plant materials and organic acids described above for the plant solution and sheet material are preferably used. The plant materials are preferably woody biomass, herbaceous biomass, or a mixture thereof. The organic acids are preferably one or more selected from the group consisting of formic acid, glyoxylic acid, and pyruvic acid.

[0118] The bonding method using this adhesive is preferably thermal bonding. It may be a wet method or a dry method. For example, a plant solution obtained by dissolving plant raw materials in an organic acid can be used as an adhesive for producing wood boards. Wood boards may be fiberboards (fiberboards) made by molding wood into fibers, or particleboards (fiberboards) made by crushing wood into chips. Examples of fiberboards include hardboards, insulation boards, and MDF (medium-density fiberboards). Particleboards and fiberboards can be obtained by adding the plant solution to various wood chips or fibers, mixing them, and then pressing them under high humidity and pressure. These are wood boards made from 100% plant materials and do not contain chemicals such as organic solvents.

[0119] The preferred requirements for the adhesive are the same as those for the sheet material of the present disclosure, and therefore, the description of the preferred requirements for the adhesive will be omitted in this section.

[0120] When the sheet material of the present disclosure is to be used as an adhesive for joining components made of various materials, it is preferable that the adhesive be a sheet material containing a divalent or higher fatty acid and / or its anhydride, because this allows for milder conditions when integrating the substrate and the sheet material. Including a divalent or higher fatty acid and / or its anhydride in the sheet material also improves the ductility and adhesive strength (adhesion) of the sheet material. The preferred content range and timing of incorporation of the divalent or higher fatty acid and / or its anhydride in a sheet material containing a divalent or higher fatty acid and / or its anhydride, as well as the preferred thermocompression temperature range when using the sheet material as an adhesive for joining components, are as described above. Therefore, the ranges are omitted here.

[0121] A more detailed description will be given below using fiberboard as an example.

[0122] In the wet process, wood is defibrated with an organic acid (e.g., formic acid) to prepare a pulp solution. This pulp solution contains a plant solution obtained by dissolving plant materials in the organic acid as an adhesive. A sizing agent is added to this pulp solution as needed to impart water resistance and strength, and the fibers dispersed in the solution are then cast onto a wire mesh and dehydrated to form a mat. The resulting wet mat is compressed and dehydrated in a prepress, followed by drying under heat and pressure to produce a fiberboard.

[0123] In dry processes, a large amount of adhesive is usually required to bond the dry fibers. However, according to the technology of the present disclosure, adding an organic acid (e.g., formic acid) during the manufacturing process allows a plant solution obtained by dissolving plant materials in the organic acid to coexist as an adhesive component. According to the present disclosure, since a large amount of water is not used as in wet processes, dehydration on a wire mesh is not required, and fiberboards with smooth surfaces can be obtained. In this method, it is sufficient that formylated plant-derived components are present along with the fibers during heat pressing. Therefore, the organic acid needs to be added at least before heat pressing; for example, it may be added during the defibration of the wood or just before the wood is sent air-dried.

[0124] The following describes its application to particle board. Particle boards are classified into single-layer, three-layer, and multi-layer types depending on their structure. Three-layer boards are composed of small pieces on both surface layers (front and back layers) and relatively coarse pieces in the inner layer (core layer). Multi-layer boards are composed of a continuous progression from fine pieces to coarse pieces from the surface to the center layer. The adhesive of the present disclosure can be applied to any of these structures.

[0125] Specifically, in the particleboard manufacturing process, wood is cut, crushed, and dried, and then adhesive is sprayed onto the resulting wood pieces using a glue blender and mixed to homogenize (gluing). By using the adhesive of the present disclosure instead of conventional adhesives, particleboard made from 100% plant materials can be obtained that does not emit formaldehyde or other substances.

[0126] For example, when manufacturing a three-layer board, small pieces of wood of different sizes are used to glue the surface and core layers together, and then the surface layer, core layer, and surface layer are laminated in this order to form a three-layer mat. This three-layer mat is compressed at high temperature and pressure, and the formylated plant-derived components bond and integrate the individual wood pieces to obtain a three-layer board.

[0127] In addition, oriented strand board (OSB) is intended to be used in building structures (as a base) to increase its strength, without taking into consideration its surface properties. By producing OSB using the adhesive of the present disclosure and then laminating and adhering the sheet material of the present disclosure to the surface of the OSB, a high-strength laminated material with a decorated surface can be obtained.

[0128] In view of the above, the technology of the present disclosure is a method for bonding wood pieces, which includes adding an organic acid to fragmented wood and heating the resulting mixture, and is also a method for manufacturing a wood board. In another view, the present disclosure is a method for bonding biomass pieces, which includes adding an organic acid to fragmented biomass material and heating the resulting mixture, and is also a method for manufacturing a biomass product.

[0129] The effects of the present disclosure will be clarified below by examples, but the present disclosure should not be interpreted as being limited based on the description of these examples.

[0130] (Production of Sheet Material) [Production Example 1] 200 mg of eucalyptus chips, a plant raw material, was placed in a 50 ml vial. 20 ml of 80 wt % formic acid (manufactured by Nacalai Tesque) was added to the vial, and the pressure was reduced. The pressure was then returned to atmospheric pressure, the temperature was raised to 50°C, and stirring was initiated. After stirring for 7 days at normal pressure, the disappearance of the eucalyptus wood flour was visually confirmed, yielding a uniform plant solution (also referred to as woody solution). The entire amount of this woody solution was cast onto cellophane and then left overnight in a lidded culture dish at room temperature to remove the liquid components, yielding a sheet material with an average thickness of 16 μm. The appearance of this sheet material is shown in FIG. 7 . The surface condition of the sheet material observed using a scanning electron microscope is shown in FIG. 10 (magnification: 500x). Fourier transform infrared spectroscopy (FTIR) of this sheet material revealed a peak at 1715-1725 cm in the infrared absorption spectrum. －１ It was confirmed that the compound exhibited an infrared absorption peak due to the formyl group in the region of

[0131] [Production Examples 2] to [Production Examples 6] Sheet materials of Production Examples 2 to 6 were obtained in the same manner as Production Example 1, except that the type of plant raw material and the dissolution conditions were changed as shown in Table 1 below. When these sheet materials were subjected to Fourier transform infrared spectroscopy (FTIR analysis), all of them showed a peak at 1715 to 1725 cm in the infrared absorption spectrum. －１ It was confirmed that an infrared absorption peak due to formyl groups was observed in the region of Figure 8. The appearances of the sheet materials of Production Examples 2 and 5 are shown in Figures 8 and 9, respectively. Figure 11 shows the surface condition of the sheet material of Production Example 4 observed with a scanning electron microscope (magnification: 500x).

[0132] [Production Example 7] The type of plant raw material and dissolution conditions were the same as in Production Example 5, but the thickness of the liquid when the plant solution was cast onto cellophane was changed to obtain a sheet material of Production Example 7 with an average film thickness of 30 μm.

[0133] [Production Example 8] First, a uniform plant solution (also referred to as wood solution) was obtained in the same manner as in Production Example 1. Next, 150 mg of citric acid (manufactured by Nacalai Tesque, Inc., product number 08899-75) was added to this wood solution to obtain a citric acid-containing wood solution. Next, the entire amount of the citric acid-containing wood solution was cast onto cellophane, and then left to stand overnight in a lidded culture dish at room temperature to remove the liquid components, thereby obtaining a sheet material with an average thickness of 50 μm. The appearance of this sheet material is shown in FIG. 19. When this sheet material was subjected to Fourier transform infrared spectroscopy (FTIR analysis), a peak at 1715-1725 cm in the infrared absorption spectrum was observed. －１ It was confirmed that the compound exhibited an infrared absorption peak due to the formyl group in the region of

[0134] [Production Example 9] First, a uniform plant solution (also referred to as wood solution) was obtained in the same manner as in Production Example 4. Next, 150 mg of citric acid (Nacalai Tesque, product number 8899-75) was added to this wood solution to obtain a citric acid-containing wood solution. Next, the entire amount of the citric acid-containing wood solution was cast onto cellophane, and then left to stand overnight in a lidded culture dish at room temperature to remove the liquid components, thereby obtaining a sheet material with an average thickness of 50 μm. The appearance of this sheet material is shown in Figure 20. When this sheet material was subjected to Fourier transform infrared spectroscopy (FTIR analysis), a peak was observed in the infrared absorption spectrum at 1715 to 1725 cm. －１ It was confirmed that the compound exhibited an infrared absorption peak due to the formyl group in the region of

[0135] [Production Example 10] A sheet material having an average thickness of 50 μm was obtained in the same manner as in Production Example 8, except that 200 mg of bamboo chips were used instead of 200 mg of eucalyptus chips. The appearance of this sheet material is shown in Figure 21. When this sheet material was subjected to Fourier transform infrared spectroscopy (FTIR analysis), a peak at 1715 to 1725 cm in the infrared absorption spectrum was observed. －１ It was confirmed that the compound exhibited an infrared absorption peak due to the formyl group in the region of

[0136] (Evaluation of Physical Properties of Sheet Materials) The physical properties of the sheet materials of Production Examples 1 to 7 were evaluated by the following methods. The evaluation results are shown in Table 1 below.

[0137] [Density] The apparent density (g / cm 3 ) of the sheet material was measured in accordance with JIS Z 8807 "Method for measuring density and specific gravity of solids." ３ The average of five measurements is shown in Table 1 below.

[0138] [Contact Angle] The contact angle in this disclosure is a dynamic contact angle, which measures the change in contact angle immediately after a droplet is dropped. Measuring the dynamic contact angle requires specifying the time. A contact angle meter (manufactured by Nick Corporation) was used to measure the contact angle. Three measurements were taken in contact angle measurement mode with a maximum measurement time of 1200 seconds (0-1 second and 1-1200 seconds), and the average value was calculated. The maximum contact angle from 0 to 1 second after dropping distilled water is shown in Table 1 below.

[0139] [Evaluation of Tensile Properties] The sheet material was punched into a dumbbell shape (No. 7 dumbbell) to prepare test specimens for tensile testing. A tensile testing machine (trade name "Universal Tensile Tester (Tensilon) RTG-B10" manufactured by A&D Co., Ltd.) was used for the tensile test. The tensile test (tensile speed: 2 mm / min, grip distance: 20 mm, gauge length: 12 mm) was performed in accordance with the provisions of ISO 527-1 to measure Young's modulus (unit: MPa), maximum stress (unit: MPa), and maximum elongation (unit: %) (temperature: 23°C, humidity: 50%). The average of five measurements is shown in Table 1 below.

[0140] [Glass Transition Temperature] The glass transition temperature of the sheet material was measured using a dynamic viscoelasticity measuring device (manufactured by TA Instruments under the trade name "RSA G2"). The measurement was performed in a nitrogen atmosphere at a temperature range of -30 to 300°C, at a heating rate of 5°C / min, with an applied strain of 0.05%, and at a frequency of 10 Hz. The measurement results are shown in Table 1 below as Tg.

[0141]

[0142] (Production of Laminated Material) [Example 1] A scrap piece of red pine (4 cm x 5 cm) was prepared as a substrate. The surface of this substrate was polished using abrasive paper #80-120, abrasive paper #100-120, and abrasive paper #120-240 in that order. The sheet material (2.5 cm x 3.5 cm) of Production Example 2 was laminated on the polished surface, and pressure (11 MPa) was applied at 200°C for 10 minutes using a heat press to obtain the laminated material of Example 1. It was visually confirmed that the sheet material after heat and pressure bonding was integrated with the substrate and could not be peeled off.

[0143] [Example 2-4] In Example 2-4, the laminated material of Example 2-4 was obtained in the same manner as in Example 1, except that the sheet materials of Production Examples 3, 5, and 6 were used. It was confirmed that the sheet material and the substrate were integrated by thermocompression bonding in all of the laminated materials.

[0144] [Example 5-120] The materials of the substrates were as shown in Table 2 below, and the laminates of Examples 5-120 were produced by using the sheet materials of Production Examples 2, 3, 5, and 6 for each substrate. The sizes of the substrates and sheet materials and the heat-pressing conditions were as described above in Example 1. The resulting laminates were visually observed to confirm that the sheet materials and substrates were integrated. Photographs of the appearance of the laminates of Examples 85, 87, 41, and 43 are shown in Figures 1-4, respectively. Figure 5 is a photograph of the appearance of the substrate (beech scrap wood) used in Examples 85 and 87, and Figure 6 is a photograph of the appearance of the substrate (cedar scrap wood) used in Examples 41 and 43.

[0145]

[0146] [Scratch Test] The pencil hardness of the laminate was measured in accordance with JIS K5600-5-4 "Scratch Hardness (Pencil Method)." Specifically, Mitsubishi High-Uni pencils (hardness: 6H, 5H, 4H, 3H, 2H, H, F, HB, B, 2B, 3B, 4B, 5B, and 6B) were prepared, and the pencil was placed at a 45-degree angle relative to the surface of the laminate to which the sheet material was attached, and scratches were performed under a constant load. If the sheet material could be drawn with the pencil without being damaged, it was considered a "pass," and if the sheet material was torn or turned up and damaged, it was considered a "fail." Note that if the sheet material did not break even when the pencil sunk into it and deformed into a concave shape, it was considered a "pass." The hardest of the hardnesses that passed was taken as the pencil hardness. Those that passed with a hardness of 6H were considered "6H or higher hardness," and those that failed with a hardness of 6B were considered "6B or higher softness."

[0147] Example 121 Beech scrap (4 cm x 5 cm) was prepared as a substrate. The surface of this substrate was polished using abrasive paper #80-120, abrasive paper #100-120, and abrasive paper #120-240 in that order. The sheet material (2.5 cm x 3.5 cm) of Production Example 2 was laminated on the polished surface, and a heat press was used to apply pressure (11.2 MPa) at 200°C for 10 minutes to obtain a laminate. A scratch test of this laminate was performed, and the pencil hardness was found to be 6H or higher.

[0148] [Examples 122-129] Laminates of Examples 122-129 were obtained in the same manner as in Example 121, except that the substrate and sheet material were changed to those shown in Table 3 below. The pencil hardness measured by the scratch test is shown in Table 3 below.

[0149] The pencil hardness of each of the sheet materials of Production Examples 2, 3, 5 and 6 was measured by scratching test without being hot pressed. The measurement results are shown in Table 3.

[0150]

[0151] As shown in Table 3, it was confirmed that the laminated materials of Examples 121-129 all had a pencil hardness of B or higher. In addition, as shown by a comparison between Comparative Examples 1-4 and Examples 121-129, it was confirmed that all of the sheet materials had a harder pencil hardness when laminated by hot pressing.

[0152] [Example 130] A corrugated cardboard board was prepared as a substrate. The surface of this substrate was polished using abrasive paper #1000. The sheet material (2.5 cm x 3.5 cm) of Production Example 2 was laminated on the polished surface, and pressed (1 t) at 180 ° C for 20 minutes using a hot press to obtain a laminate of Example 130. The obtained laminate was visually observed to confirm that the sheet material and the substrate were integrated. A photograph of the appearance of the laminate of Example 130 is shown in Figure 12.

[0153] [Examples 131-138] Laminates of Examples 131-138 were obtained in the same manner as in Example 130, except that the types of substrate and sheet material and the heat press conditions were changed to those shown in Table 4 below. It was visually confirmed that the sheet material and substrate were integrated in each laminate. Photographs of the appearance of the laminates of Examples 131, 133, 137, and 138 are shown in Figures 13-16, respectively.

[0154]

[0155] [Example 139] Hinoki cypress slices (veneer, size: 3 cm x 3 cm) were prepared as the first and second substrates. The sheet material of Production Example 7 (thickness: 30 μm, size: 2 cm x 2 cm) was placed between the first and second substrates, and pressed (1 t) at 200 ° C for 4 minutes using a heat press to obtain the laminate of Example 139. Visual inspection confirmed that the sheet material after thermocompression bonding was integrated with each substrate. It was also confirmed that the first substrate and the second substrate were firmly bonded via the sheet material and could not be peeled off. A photograph of the appearance of the laminate of Example 139 is shown in FIG. 17.

[0156] [Examples 140-141] The laminates of Examples 140-141 were obtained in the same manner as in Example 142, except that the load during hot pressing was changed to 400 kg. Visual inspection confirmed that the sheet material after hot pressing was integrated with the substrate, and that the first substrate and the second substrate were firmly bonded via the sheet material and could not be peeled off. In addition, it was confirmed that deformation (thickness reduction) due to hot pressing could be suppressed by changing the load during hot pressing from 1000 kg to 400 kg.

[0157] [Example 142] A cedar wood chip (thickness: 1.0 cm, size: 4 cm x 5 cm) was prepared as the first substrate, and the laminate of Example 142 was obtained in the same manner as in Example 139, except that the heat pressing conditions were changed to those shown in Table 5 below. Visual inspection confirmed that the sheet material after heat pressing was integrated with each substrate, and that the first substrate and the second substrate were firmly bonded via the sheet material and could not be peeled off. A photograph of the appearance of the side of the laminate of Example 142 is shown in Figure 18.

[0158]

[0159] [Example 143] Beech scrap (4 cm x 5 cm) was prepared as a substrate. The surface of this substrate was polished using abrasive paper #80-120, abrasive paper #100-120, and abrasive paper #120-240 in that order. The sheet material (2.5 cm x 3.5 cm) of Production Example 8 was laminated on the polished surface, and pressure (5 MPa) was applied at 90 ° C. for 15 minutes using a hot press to obtain the laminate of Example 143.

[0160] Example 144 A laminated material of Example 144 was obtained in the same manner as in Example 143, except that cedar scraps (4 cm x 5 cm) were used as the substrate instead of beech scraps.

[0161] Example 145 A laminated material of Example 145 was obtained in the same manner as in Example 143, except that the sheet material of Production Example 9 was used instead of the sheet material of Production Example 8.

[0162] Example 146 A laminated material of Example 146 was obtained in the same manner as in Example 144, except that the sheet material of Production Example 9 was used instead of the sheet material of Production Example 8.

[0163] Example 147 A laminated material of Example 147 was obtained in the same manner as in Example 143, except that the sheet material of Production Example 10 was used instead of the sheet material of Production Example 8.

[0164] Example 148 A laminated material of Example 148 was obtained in the same manner as in Example 144, except that the sheet material of Production Example 10 was used instead of the sheet material of Production Example 8.

[0165] It was visually confirmed that the laminated materials of Examples 143 to 148 were integrated with the substrate after heat and pressure bonding and could not be peeled off. Furthermore, the laminated materials of Examples 143 to 148 were surface-modified, similar to the laminated materials in which the substrate and the sheet material not containing citric acid were integrated, and the appearance of the sheet material side became more glossy. Therefore, they have excellent effects as laminated materials.

[0166] Thus, sheet materials containing divalent or higher fatty acids and / or their anhydrides can be integrated with substrates under milder conditions than sheet materials that do not contain divalent or higher fatty acids and / or their anhydrides. Furthermore, laminates in which a substrate is integrated with a sheet material containing divalent or higher fatty acids and / or their anhydrides are surface-modified as described above, and the appearance of the sheet material side is more glossy. Therefore, sheet materials containing divalent or higher fatty acids and / or their anhydrides are very useful for producing glossier laminates under milder conditions.

[0167] As shown in the examples, according to the present disclosure, laminated materials can be obtained in which substrates of various materials and sheet materials are integrated without using chemicals such as organic solvents or adhesives. The technology of the present disclosure can be applied to surface modification of molded products of various materials, improving the appearance of low-quality wood, and repairing wood molded products that have deteriorated over time. Furthermore, the technology of the present disclosure can also be applied as an adhesive for joining components of various materials. The above evaluation results clearly demonstrate the superiority of the present disclosure.

Claims

1. The device includes a first substrate and a sheet material laminated and integrated onto a surface of the first substrate, The material of the first substrate is selected from the group consisting of biomass materials, plastics, metals, ceramics, glass, pulp molds, and paper; The sheet material is formed substantially from plant-derived components, In the infrared absorption spectrum of the above sheet material, -1 A laminate showing an absorption peak in the region of

2. The density of the sheet material is 0.2 g / cm 3 1.2g / cm or more 3 2. The laminate of claim 1, wherein:

3. The laminate according to claim 1 or 2, wherein the plant-derived component is one or more selected from the group consisting of cellulose, hemicellulose and lignin.

4. 4. The laminate according to claim 3, wherein a part or all of the hydroxyl groups of the cellulose, hemicellulose and lignin are formylated.

5. 5. The laminate according to claim 1, wherein the sheet material comprises a di- or higher fatty acid and / or anhydride thereof.

6. Further comprising a second substrate laminated and bonded to the first substrate via the sheet material; 5. The laminate according to claim 1, wherein the material of the second substrate is selected from the group consisting of biomass materials, plastics, metals, ceramics, glass, molded pulp, and paper.

7. A sheet material for use in the laminate material according to any one of claims 1 to 6.

8. dissolving the plant material in an organic acid to obtain a plant solution; removing liquid components from the plant solution to obtain a sheet material formed substantially from plant-derived components; and The sheet material is laminated on a surface of the first substrate and heat-pressurized to obtain a laminated material in which the sheet material and the first substrate are integrated; A method for producing the laminate of claim 1, comprising:

9. The method of claim 8 further comprising sanding the first substrate prior to laminating the sheet materials.

10. dissolving the plant material in an organic acid to obtain a plant solution; removing liquid components from the plant solution to obtain a sheet material formed substantially from plant-derived components; and placing the sheet material between the first substrate and the second substrate and heat-pressing the sheet material to laminate the first substrate and the second substrate; A method for producing the laminate according to claim 6, comprising:

11. The method of claim 10, further comprising sanding the first and second substrates before applying the sheet material.

12. The method for producing a laminated material according to any one of claims 8 to 11, wherein the plant raw material is woody biomass, herbaceous biomass, or a mixture thereof.

13. The method for producing a laminated material according to any one of claims 8 to 12, wherein the organic acid is one or more selected from the group consisting of formic acid, glyoxylic acid and pyruvic acid.

14. The method for producing a laminated material according to any one of claims 8 to 13, wherein the temperature at which the plant raw material is dissolved in the organic acid is 20°C or higher and 80°C or lower.

15. The method for producing a laminate according to any one of claims 8 to 14, wherein the temperature of the heat-pressure bonding is 220°C or less.

16. dissolving the plant material in an organic acid to obtain a plant solution; removing liquid components from the plant solution to obtain a sheet material formed substantially from plant-derived components; and Laminating the sheet material on the surface of the molded product and heat-pressing it; A method for modifying the surface of a molded article, comprising:

17. An adhesive comprising a sheet material consisting essentially of plant-derived components obtained by dissolving a plant raw material in an organic acid and removing liquid components from the resulting plant solution.

18. 18. The adhesive of claim 17, wherein the plant material is woody biomass, herbaceous biomass, or a mixture thereof.

19. 19. The adhesive of claim 17 or 18, wherein the sheet material comprises di- or higher fatty acids and / or anhydrides thereof.

20. 20. The adhesive according to claim 17, wherein the organic acid is one or more selected from the group consisting of formic acid, glyoxylic acid, and pyruvic acid.

21. An adhesive comprising a plant solution obtained by dissolving a plant raw material in an organic acid, the plant solution containing a plant-derived component, the plant-derived component being one or more selected from the group consisting of cellulose, hemicellulose and lignin, and some or all of the hydroxyl groups of the cellulose, hemicellulose and lignin being formylated.

22. A laminated material described in any one of claims 1 to 5, laminated so that the main surface of the first substrate and the main surface of the sheet material are in contact.

23. A molded body in which components are bonded together using the adhesive described in claim 21.

24. The molded body described in Claim 23, which is a wood board.

25. A molded body as described in claim 23 or 24, wherein the component is wood in chip form or fibrous form.