Composite and method for producing composite

Abstract

To provide a composite and a method of producing the composite, wherein the composite exhibits superior mechanical strength and resistance to moisture, along with favorable texture.SOLUTION: A composite having mushroom mycelium, a binder which includes in one molecule two or more carboxyl groups and is bound to the mycelium, and a metal cation having a valence of 2 or more, wherein the carboxyl groups are ionically crosslinked to each other via the metal cation. It is preferable that the composite further includes a fiber. The fiber preferably includes cellulose.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composite and a method for producing the composite. [Background technology]

[0002] In recent years, there has been a market demand for products made from naturally derived materials that have a low environmental impact. For example, Patent Document 1 discloses a cultured mycelium material containing branched mycelia formed by breaking one or more clumps and a binder having a carboxyl group. This configuration allows the production of a cultured mycelium material with good mechanical strength and aesthetic quality. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2022-534025 Summary of the Invention [Problem to be solved by the invention]

[0004] However, binders with carboxyl groups are hydrophilic. Therefore, cultured mycelium materials have low moisture resistance, and when placed in a high-humidity environment, for example, their mechanical strength decreases. In addition, there is room for improvement in the texture of the cultured mycelium materials, which limits their applications.

[0005] Therefore, it is desired to realize a composite that has excellent mechanical strength and moisture resistance as well as a good texture. [Means for solving the problem]

[0006] The composite according to the application example of the present invention is Mushroom mycelium and A binder containing two or more carboxyl groups per molecule and binding to the mycelium; a divalent or higher metal cation; and The carboxy groups are ionically crosslinked with each other via the metal cations.

[0007] A method for producing a composite according to an application example of the present invention includes the steps of: A method for producing a composite according to an application example of the present invention, comprising the steps of: a step of subjecting the sheet containing the mycelia to hydrolysis treatment; a step of contacting the hydrolyzed sheet with a binder containing two or more carboxy groups per molecule to bond the sheet to the binder; a step of contacting the sheet to which the binder is bound with the metal cations and ionically cross-linking the carboxy groups with each other via the metal cations to obtain the composite; It has. [Brief explanation of the drawings]

[0008] [Figure 1] 1A to 1C are process diagrams showing the configuration of a method for producing a composite according to an embodiment. [Figure 2] Table 1 shows the configuration of the composites of each example and each comparative example and the evaluation results of the composites. [Figure 3] Table 2 shows the configuration of the composites of each Example and Comparative Example and the evaluation results of the composites. [Figure 4] Table 3 shows the configuration of the composites of each Example and Comparative Example and the evaluation results of the composites. DETAILED DESCRIPTION OF THE INVENTION

[0009] The composite and the method for producing the composite of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings.

[0010] 1. Complex First, the composite according to the embodiment will be described.

[0011] The composite according to the embodiment includes mushroom mycelia, a binder, divalent or higher metal cations, and fibers.

[0012] 1.1. Mushroom mycelium Mushroom mycelia are the fibrous structures that make up the mycelium of mushrooms. The type of mushroom is not particularly limited, but examples thereof include Agaricus arvensis, Agrocybe brasiliensis, Amylomyces rouxii, species of the genus Amylomyces, Armillaria mellea, Aspergillus nidulans, Aspergillus niger, Aspergillus oryzae, Ceriporia lacerata, Coprinus comatus, Fibroporia vaillantii, Fistulina hepatica, Flammulina velutipes, and the like. velutipes, Fomitopsis officinalis, Ganoderma sessile, Ganoderma tsugae, Hericium erinaceus, Hypholoma capnoides, Hypholoma sublaterium, Inonotus obliquus, Lactarius chrysorrheus, Macrolepiota procera, Morchella angusticeps, Myceliophthora thermophila, Neurospora crassa crassa, Penicillium camembertii, Penicillium chrysogenum, Penicillium rubens, Phycomyces brachestrianusblakesleeanus, Pleurotus djamor, Pleurotus ostreatus, Polyporus squamosus, Psathyrella aquatica, Rhizopus microspores, Rhizopus oryzae, Schizophyllum commune, Streptomyces venezuelae, Stropharia rugosoannulata, Thielavia terrestris, Ustilago maydis), shiitake mushrooms (Lentinula genus), tomboy mushrooms (Meripilus genus), maitake mushrooms (Grifola genus), giant ginkgo mushrooms (Leucopaxillus genus), polyporaceae (Fomitopsis genus), and matsutake mushrooms (Tricholoma genus).

[0013] The mushroom mycelia may be aggregated together to form a mycelium. In other words, some or all of the mycelia in the complex may be mycelia formed by aggregation of mycelia. In the following description, mushroom mycelia will also be simply referred to as "mycelium."

[0014] The average diameter of the hyphae is preferably set to be smaller than the average diameter of the fibers, which makes it easier to impart the smooth texture derived from the hyphae to the composite.

[0015] The average diameter of the hyphae is not particularly limited, but is preferably 0.1 μm to 5.0 μm, more preferably 0.3 μm to 3.0 μm. If the average diameter of the hyphae is within this range, the texture of the composite can be particularly improved.

[0016] The average diameter of the hyphae is measured as follows. First, the complex is enlarged and an image is taken so that at least 100 hyphae fit within a single image. Next, at least 10 hyphae are randomly selected and their widths are measured. The average of these measurements is then used as the average hypha diameter.

[0017] The average length of the hyphae is not particularly limited, but is preferably 0.001 mm to 3.0 mm, more preferably 0.010 mm to 2.0 mm, and even more preferably 0.050 mm to 1.0 mm. If the average length of the hyphae is within the above range, for example, when the composite is formed into a sheet, the hyphae will be oriented along the surface of the composite and will be moderately entangled with each other. This will particularly improve the texture of the composite.

[0018] The average length of the hyphae is measured as follows. First, the complex is enlarged and an image is taken so that at least 100 hyphae fit within a single image. Next, at least 10 hyphae are randomly selected and the maximum length possible within the hyphae image is measured. The average of these measurements is then used as the average hypha length.

[0019] 1.2.Binder The binder contains two or more carboxyl groups per molecule, and binds to the mycelium. "Binding to the mycelium" refers to the presence of a chemical bond between the carboxyl group contained in the binder and the organic group contained in the mycelium. Specifically, the carboxyl group contained in the binder forms an ester bond with the hydroxyl group contained in the mycelium. The ester bond firmly binds the mycelium together.

[0020] Furthermore, when the composite contains fibers, it is preferable that the binder also binds to the fibers in addition to the mycelia. In this case, too, the carboxyl groups contained in the binder form chemical bonds such as ester bonds with the hydroxyl groups contained in the fibers. This allows the fibers to be firmly bound together and the mycelia to the fibers.

[0021] The mycelia preferably contain chitin. Chitin is contained as a component of the cell wall that constitutes the mycelia. Chitin is a polymeric polysaccharide whose structural unit is N-acetylglucosamine, which is glucose to which an acetamide group (-NHCOCH3) is added. Since chitin has a hydroxyl group, the mycelia containing chitin can easily form an ester bond with a binder.

[0022] Furthermore, the acetamide groups contained in chitin are deacetylated and converted to amino groups by the hydrolysis treatment described below. The amino groups react with carboxyl groups to form amide bonds. Therefore, the hydrolysis treatment makes it easier for the mycelia to form amide bonds with the binder. As a result, ester bonds and amide bonds are formed between the mycelia and the binder, which particularly enhances the mechanical strength of the composite.

[0023] In addition, the carboxyl groups contained in the binder ionically crosslink with other carboxyl groups via the metal cations described below. This crosslinks the mycelia with each other via the binder and the metal cations, increasing the mechanical strength of the composite. Furthermore, when the composite contains fibers, the fibers are crosslinked with each other and the fibers and mycelia are crosslinked with each other via the binder and the metal cations, respectively. This particularly increases the mechanical strength of the composite.

[0024] The binder is not particularly limited as long as it is a compound containing two or more carboxyl groups in one molecule, but polycarboxylic acids or polycarboxylic acid salts are preferably used, as they have many carboxyl groups and therefore can particularly increase the mechanical strength of the composite.

[0025] Examples of polycarboxylic acids include carboxypolysaccharides and organic carboxylic acids.

[0026] Among these, examples of carboxypolysaccharides include alginic acid, carboxymethyl amylose, and pectic acid.

[0027] Examples of organic carboxylic acids include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, dicarboxylic acids having a hydroxyl group, tricarboxylic acids, and amino acids having multiple carboxy groups.

[0028] Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc. Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, etc.

[0029] Examples of dicarboxylic acids having a hydroxyl group include tartaric acid and malic acid. Examples of tricarboxylic acids include citric acid and aconitic acid.

[0030] Examples of amino acids having multiple carboxy groups include aspartic acid and glutamic acid.

[0031] Polycarboxylic acid salts are salts formed by bonding a carboxy group of a polycarboxylic acid to a monovalent cation, such as an alkali metal ion such as potassium ion or sodium ion, or an ammonium ion.

[0032] Among these, the polycarboxylic acid salt is preferably an alkali metal salt of a carboxypolysaccharide, more preferably an alkali metal alginate, and even more preferably sodium alginate. Alkali metal alginate is a salt in which the carboxy group of alginic acid is bonded to an alkali metal ion. Alkali metal alginate, particularly sodium alginate, forms strong ionic crosslinks with divalent or higher metal cations in a short period of time. Furthermore, since alginic acid contains many carboxy groups, it is easy to form a network through ionic crosslinking. Therefore, by using alkali metal alginate as a binder, the mechanical strength of the composite can be particularly increased.

[0033] The binder content in the composite is preferably 1.0% by mass to 90.0% by mass, more preferably 1.5% by mass to 85.0% by mass, even more preferably 1.5% by mass to 80.0% by mass, and particularly preferably 5.0% by mass to 80.0% by mass. If the binder content in the composite is within this range, sufficient mechanical strength can be obtained.

[0034] 1.3.Divalent or higher metal cations Divalent or higher metal cations contribute to ionic cross-linking between carboxyl groups. Ionic cross-linking cross-links hyphae with each other, fibers with each other, and fibers with hyphae. This causes gelation of the ionically cross-linked product, increasing the mechanical strength of the composite. In the following description, "divalent or higher metal cations" will also be referred to simply as "metal cations."

[0035] The metal cation is not particularly limited, but ions of at least one metal element selected from the group consisting of Ca, Mg, Ba, Cu, Fe, Al, and Zn are preferably used. These ions are useful as metal cations to be added to the composite because they are less likely to affect the properties of the composite. This can stabilize the properties of the composite.

[0036] The metal cation also contributes to suppressing the reactivity of the carboxyl group. Because the carboxyl group is hydrophilic, when the metal cation acts on the carboxyl group contained in the binder, the hydrophilicity of the composite is suppressed, thereby improving the moisture resistance of the composite.

[0037] The content of metal cations in the composite is measured as follows. First, 10 mg of the composite is cut out to prepare a test piece. Next, this test piece is immersed in 10 mL of a 30% by mass aqueous solution of sodium hydroxide. This causes the metal cations contained in the test piece to elute. Next, the solution containing the eluted metal cations is quantitatively analyzed using high-performance liquid chromatography to measure the concentration of the metal cations. The obtained concentration is taken as the content of the metal cations in the composite.

[0038] The metal cation content in the complex determined in this way is 3 × 10 -6 mol / L or more 170×10 -6 mol / L or less, and preferably 5×10 -6 mol / L or more 100×10 -6 mol / L or less is more preferable, and 10×10 -6 mol / L or more 80×10 -6 It is more preferable that the concentration is 100 mol / L or less.

[0039] By setting the content of the metal cation within the above range, the amount of the metal cation relative to the binder can be optimized, which can sufficiently increase the moisture resistance of the composite and prevent the problem of excess metal cations being eluted without being retained in the composite.

[0040] If the content of metal cations is below the lower limit, the amount of metal cations relative to the binder may be insufficient, which may result in a decrease in the moisture resistance of the composite. On the other hand, if the content of metal cations is above the upper limit, the amount of metal cations may be excessive relative to the binder. In this case, the excess metal cations may be eluted from the composite.

[0041] Fiber The composite may also contain fibers, which can further increase the mechanical strength of the composite.

[0042] The fibers are not particularly limited, and a wide variety of fiber materials can be used. Examples of fibers include natural fibers such as animal fibers and plant fibers, and chemical fibers such as organic fibers, inorganic fibers, and organic-inorganic composite fibers. Specifically, at least one selected from the group consisting of cellulose, silk, wool, cotton, hemp, kenaf, flax, ramie, jute, Manila hemp, sisal, coniferous trees, and broad-leaved trees is preferably used. These may be used alone or in appropriate mixtures, or may be used as regenerated fibers that have been purified, etc.

[0043] Examples of raw materials for the fibers include waste paper and old cloth, and the fibers may contain at least one of the above fibers. The fibers may also be subjected to various surface treatments. The fiber material may be a pure substance, or may contain multiple components such as impurities, additives, and other components.

[0044] Among these, fibers containing cellulose are more preferable. Cellulose contains many hydroxyl groups in its molecular structure. Therefore, it easily reacts with the binder, and it is easy to improve the mechanical strength and moisture resistance of the composite.

[0045] The average diameter of the fibers is not particularly limited, but is preferably thicker than the average diameter of the mycelia. Specifically, it is preferably 1.0 μm or more and 20.0 μm or less, and more preferably 3.0 μm or more and 15.0 μm or less. If the average diameter of the fibers is within this range, the mechanical strength of the composite can be particularly increased.

[0046] The average diameter of the fibers is measured as follows. First, the composite is magnified and an image is taken so that at least 100 fibers fit within one image. Next, at least 10 fiber images are randomly selected and the width of the fiber images is measured. The average of these measurements is then taken as the average fiber diameter.

[0047] The average length of the fibers is not particularly limited, but is preferably 0.001 mm to 5.0 mm, more preferably 0.002 mm to 3.0 mm, and even more preferably 0.003 mm to 2.0 mm. When the average fiber length is within this range, the fibers are oriented along the surface of the composite, for example, and the fibers are moderately entangled with each other. This can particularly increase the mechanical strength of the composite.

[0048] The average fiber length is measured as follows. First, the composite is magnified and an image is taken so that at least 100 fibers fit within one image. Next, at least 10 fiber images are randomly selected, and the maximum length possible within the fiber image is measured. The average of the measurements is then taken as the average fiber length.

[0049] 1.5.Additives The composite may also contain any additives, such as plasticizers, stabilizers, antioxidants, ultraviolet absorbers, lubricants, flame retardants, antistatic agents, and fillers, and one or more of these may be used.

[0050] Examples of plasticizers include sugar alcohols, vegetable oils, adipate ester plasticizers, phthalate ester plasticizers, trimellitate ester plasticizers, polyester plasticizers, (meth)acrylic ester polymers, ethylene copolymer elastomers, chlorinated polyethylene (CPE), (meth)acrylic resins (PMMA), polystyrene resins (PS), polyvinyl acetate resins (PVAc), acrylonitrile-butadiene rubber (NBR), and styrene-butadiene rubber (SBR).

[0051] Examples of sugar alcohols include maltitol, lactitol, tetritol, pentitol, hexitol, erythritol, sorbitol, xylitol, mannitol, and glycerin.

[0052] Examples of vegetable oils include epoxidized vegetable oils such as epoxidized soybean oil (ESBO) and epoxidized linseed oil (ELSO).

[0053] The composite preferably contains glycerin or vegetable oil. By containing these, the flexibility of the composite can be increased, and as a result, the texture of the composite can be further improved.

[0054] The content of the plasticizer in the composite is not particularly limited, but is preferably 10.0% by mass or less, more preferably 0.1% by mass to 7.0% by mass, and even more preferably 0.5% by mass to 4.0% by mass, which allows a composite to be obtained that has both mechanical strength and flexibility.

[0055] 1.6. Composite Forming The composite is formed, for example, by mixing mycelia, a binder, metal cations, and fibers and then applying heat to the mixture, which promotes chemical bonding between the mycelia, between the mycelia and fibers, and between the fibers.

[0056] The mixing ratio of the mycelia, binder, metal cations, and fibers in the composite can be appropriately set depending on the application and required performance of the composite, and can be expressed, for example, by the total content of the binder and metal cations in the composite and the ratio of the mycelia content to the fibers.

[0057] The total content of the binder and metal cations in the composite is preferably 1.0% by mass to 90.0% by mass, more preferably 1.5% by mass to 85.0% by mass, even more preferably 1.5% by mass to 80.0% by mass, and particularly preferably 5.0% by mass to 80.0% by mass. If the total content of the binder and metal cations in the composite is within the above range, the mixing ratio of the mycelium, binder, metal cations, and fibers is optimized, and sufficient mechanical strength, moisture resistance, and texture are obtained.

[0058] The mass ratio of mycelia to fiber is preferably 0.10 to 9.0, more preferably 0.20 to 5.0, and even more preferably 0.30 to 3.0. If the ratio of mycelia to fiber content is within the above range, a good balance between high mechanical strength and good texture can be achieved in the composite.

[0059] If the mass ratio of mycelia to fibers is below the lower limit, the texture of the composite may be deteriorated, whereas if the mass ratio of mycelia to fibers is above the upper limit, the mechanical strength of the composite may be reduced.

[0060] 1.7. Dispersion of Components in Complexes In the composite, the binder and metal cations are preferably dispersed among the hyphae and fibers. A dispersed state refers to a state in which the binder and metal cations are scattered between the hyphae, between the fibers, and between the hyphae and fibers, respectively. The binder and metal cations physically and chemically cross-link the hyphae, the fibers, and the hyphae and fibers, respectively, fixing their relative positions. This fixes and maintains the external shape of the composite, allowing the composite to maintain a desired shape, such as a sheet. Furthermore, the entangled spread of the hyphae and fibers imparts a good texture to the composite.

[0061] In addition, the composite may contain unbound hyphae and fibers, and the proportion thereof can be adjusted by adjusting the amount of binder and metal cation. The more unbound hyphae and fibers there are, the more easily deformed the composite will be. Furthermore, the more bound portions there are, the higher the rigidity and mechanical strength of the composite will be.

[0062] 1.8. Uses of the Complex The composite can be molded into various shapes as needed. The composite can be molded into two-dimensional shapes such as a sheet, board, or web, or three-dimensional shapes such as a block, rod, or sphere. Typical examples of composites include paper, nonwoven fabric, wallpaper, wrapping paper, colored paper, drawing paper, fiberboard, filters, liquid absorbents, sound absorbers, cushioning materials, mats, etc.

[0063] The composite according to this embodiment has excellent mechanical strength, moisture resistance, and texture, and is therefore particularly useful as a naturally derived material, such as a leather substitute (alternative leather).

[0064] 2. Manufacturing method of the composite Next, a method for producing the composite according to the embodiment will be described.

[0065] FIG. 1 is a process diagram showing the steps of a method for producing a composite according to an embodiment. The method for producing the composite shown in FIG. 1 includes a hydrolysis step S102, a binding step S104, and a cross-linking step S106.

[0066] 2.1. Hydrolysis process In the hydrolysis step S102, first, a sheet containing mycelia is prepared. The sheet containing mycelia is formed, for example, by gathering a large number of mycelia and molding or paper-making them into a sheet. The sheet may be flat or molded into a predetermined shape. The mycelia may be defibrated mycelia. Mycelia is an aggregate of mycelia. For example, a method of applying mechanical energy is used to defibrate mycelia. In particular, by using a defibrator, it is possible to defibrate mycelia while suppressing significant damage to the mycelia, and obtain mycelia. The defibration method may be a wet method, but a dry method is preferably used. A dry method refers to a method in which defibration is performed in air such as the atmosphere, rather than in a liquid such as water. An impeller mill capable of dry defibration is preferably used as the defibrator.

[0067] Next, the sheet containing mycelia is subjected to a hydrolysis treatment. The hydrolysis treatment hydrolyzes the components that make up the mycelia, increasing the reactivity between the mycelia and the binder. Specifically, if the mycelia contain chitin, the acetamide groups contained in the chitin are deacetylated by the hydrolysis treatment and converted into amino groups. The amino groups react with carboxy groups to form amide bonds. Therefore, by undergoing the hydrolysis treatment, amide bonds can be formed between the mycelia and the binder. This particularly increases the mechanical strength of the composite.

[0068] Examples of hydrolysis treatments include contact with an alkaline solution and enzymatic decomposition. Among these, treatment using an alkaline solution is preferred. Deacetylation can be achieved particularly efficiently with an alkaline solution. Examples of alkalis used in alkaline solutions include sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, sodium phosphate, and ammonium hydroxide. Aqueous solutions of these alkalis are preferably used. The alkali concentration in the alkaline solution is not particularly limited, but is preferably 5% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 50% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less. By setting the alkali concentration within the above range, chitin deacetylation can be achieved particularly efficiently.

[0069] The mass of alkali used for hydrolysis of 1 g of mycelium is not particularly limited, but is preferably 3 g or more, more preferably 5 g to 100 g, and even more preferably 10 g to 50 g. By setting the mass of alkali within this range, chitin deacetylation can be carried out evenly and the increase in environmental load caused by an excess alkaline solution can be suppressed.

[0070] The temperature of the alkaline solution brought into contact with the mycelia (treatment temperature) is not particularly limited, but is preferably from 10° C. to 150° C., more preferably from 50° C. to 130° C., and even more preferably from 70° C. to 110° C. Setting the treatment temperature within the above range allows for uniform deacetylation of chitin.

[0071] The time for which the mycelium is in contact with the alkaline solution (treatment time) is not particularly limited, but when the treatment is performed at the above treatment temperature, it is preferably from 0.1 to 1,000 hours, more preferably from 1 to 100 hours, and even more preferably from 3 to 50 hours. By setting the treatment time within this range, chitin deacetylation can be carried out efficiently and sufficiently.

[0072] 2.2. Binding process In the binding step S104, the hydrolyzed sheet is brought into contact with a binder containing two or more carboxy groups per molecule, thereby binding the sheet to the binder.

[0073] For example, if the mycelium contains chitin, the hydrolyzed sheet contains hydroxyl and amino groups. When the sheet is brought into contact with a binder, the carboxyl and hydroxyl groups form ester bonds, and the carboxyl and amino groups form amide bonds. This bonds the sheet to the binder.

[0074] The method for bringing the sheet into contact with the binder is not particularly limited, but examples thereof include a method of spraying a solution containing a binder onto the sheet, and a method of immersing the sheet in a solution containing a binder.

[0075] The solvent used in the solution containing the binder may be any liquid (solvent or dispersion medium) that can dissolve or disperse the binder, and examples thereof include water and various organic solvents.

[0076] The concentration of the binder in the binder-containing solution is not particularly limited, but is preferably 0.1% by mass or more and 5.0% by mass or less, and more preferably 0.3% by mass or more and 1.0% by mass or less. If the binder concentration is within this range, the viscosity of the solution is optimized, allowing the binder to be applied evenly to the sheet in a short period of time. In addition, waste due to an excessive amount of binder can be prevented.

[0077] The binder-containing solution may contain any additives, such as condensing agents, antioxidants, stabilizers, and lubricants, as needed.

[0078] Among these, the condensing agent may be a known amide condensing agent. Examples of the amide condensing agent include carbodiimide condensing agents, carbonyldiimidazole condensing agents, triazine condensing agents, phosphonium condensing agents, uronium condensing agents, and phosphoric acid condensing agents. By using such a condensing agent, the reaction conditions required to form an amide bond can be alleviated. In other words, the reaction temperature can be lowered and the reaction time can be shortened compared to when no condensing agent is used. As a result, the binding efficiency of the binder to the sheet can be improved.

[0079] Examples of carbodiimide condensing agents include dicyclohexylcarbodiimide (DCC), N-ethyl-N'-3-dimethylaminopropylcarbodiimide (EDC), and diisopropylcarbodiimide (DIPC).

[0080] Examples of carbonyldiimidazole-based condensing agents include carbonyldiimidazole (CDI) and 1,2,4-triazole (CDT).

[0081] Examples of triazine-based condensing agents include 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM).

[0082] Examples of phosphonium-based condensing agents include 1H-benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate (BOP), 1H-benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate (pyBOP), and the like.

[0083] Examples of uronium-based condensing agents include O-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU), O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HBTU), and {{[(1-cyano-2-ethoxy-2-oxoethylidene)amino]oxy}-4-morpholinomethylene}dimethylammonium hexafluorophosphate (COMU).

[0084] Examples of phosphoric acid-based condensing agents include diphenylphosphoryl azide (DPPA) and diethylphosphoryl cyanide (DEPC).

[0085] The amount of the condensing agent added is adjusted so that it is preferably 0.01 to 2.0 molar equivalents, more preferably 0.05 to 1.5 molar equivalents, relative to the amino group, in terms of the molar equivalent of the active group of the condensing agent.

[0086] After contacting the sheet with the binder-containing solution, the sheet and the binder attached thereto may be heated as needed. This removes the solvent or dispersion medium, promotes drying, and increases the reaction efficiency between the sheet and the binder.

[0087] The heating temperature may be any temperature equal to or higher than the boiling point of the solvent or dispersion medium, and is preferably 60°C or higher and 200°C or lower, and more preferably 80°C or higher and 150°C or lower.

[0088] The sheet may contain fibers. When fibers are contained, as described above, the binder also acts on the fibers, and hydroxyl groups contained in the fibers and carboxyl groups contained in the binder form ester bonds.

[0089] 2.3.Crosslinking process In the cross-linking step S106, the sheet to which the binder is bound is brought into contact with divalent or higher metal cations. This causes ionic cross-linking between carboxyl groups via the metal cations, resulting in a composite. Note that although the carboxyl groups contained in the binder are subjected to reaction with mycelia and fibers, not all of them contribute to the reaction, and some carboxyl groups remain unreacted. If such unreacted carboxyl groups remain in the composite, this will result in a decrease in the moisture resistance of the composite.

[0090] Therefore, in this embodiment, carboxy groups are ionically cross-linked via metal cations, which reduces the number of unreacted carboxy groups, thereby improving the moisture resistance of the composite.

[0091] The divalent or higher metal cations are supplied to the sheet, for example, as a solution. The solution containing the metal cations is formed, for example, by dissolving a metal cationic substance in water. The metal cationic substance can be a reaction product of a metal cation and an anion, i.e., a salt. Examples of anions include, but are not limited to, chloride ions, nitrate ions, carbonate ions, sulfate ions, lactate ions, etc. Examples of salts of divalent or higher metal cations and these anions include calcium chloride, calcium lactate, iron chloride, magnesium chloride, barium nitrate, and copper nitrate.

[0092] In the solution containing metal cations, the concentration of the salt is not particularly limited, but is preferably 0.005% by mass to 0.50% by mass, and more preferably 0.010% by mass to 0.30% by mass, which allows the metal cations to act evenly on the sheet bound with the binder in a short period of time.

[0093] After contacting the sheet with the solution containing metal cations, the sheet and the metal cations attached thereto may be heated as needed. This removes the solvent or dispersion medium, promotes drying, and increases the reaction efficiency between the binder and the metal cations.

[0094] The heating temperature may be any temperature equal to or higher than the boiling point of the solvent or dispersion medium, and is preferably 60°C or higher and 200°C or lower, and more preferably 80°C or higher and 150°C or lower.

[0095] According to the above-described method, a composite body having excellent mechanical strength and moisture resistance as well as a good texture can be produced.

[0096] 3. Effects of the above embodiment As described above, the composite according to the embodiment includes mushroom mycelia, a binder containing two or more carboxy groups per molecule and binding the mycelia, and divalent or higher metal cations. In the composite according to the embodiment, the carboxy groups are ionically cross-linked to each other via the metal cations.

[0097] According to this configuration, a composite body having excellent mechanical strength and moisture resistance and a good texture can be obtained.

[0098] The composite according to the embodiment further includes fibers. This configuration results in a composite having particularly high mechanical strength.

[0099] In the composite according to the embodiment, the fibers contain cellulose. According to this configuration, since cellulose contains many hydroxyl groups in its molecular structure, it is easy to react with the crosslinking agent, and the mechanical strength and moisture resistance of the composite are easily improved.

[0100] In the composite according to the embodiment, the metal cation is an ion of at least one metal element selected from the group consisting of Ca, Mg, Ba, Cu, Fe, Al, and Zn.

[0101] According to this configuration, the metal cations are less likely to affect the properties of the composite, and the properties of the composite can be stabilized.

[0102] In the composite according to the embodiment, the binder contains a polycarboxylic acid or a polycarboxylic acid salt. This configuration results in a composite having particularly high mechanical strength.

[0103] In the composite according to the embodiment, the content of the binder is 1.5% by mass or more and 80.0% by mass or less. With this configuration, the composite can have sufficient mechanical strength.

[0104] In addition, in the composite according to the embodiment, when 10 mg of the composite is immersed in 10 mL of a 30% by mass aqueous solution of sodium hydroxide, the concentration of the eluted metal ions is 3×10 -6 mol / L or more 170×10 -6 mol / L or less.

[0105] According to this configuration, the moisture resistance of the composite can be sufficiently increased, and the occurrence of a problem in which excess metal cations are not retained in the composite and are eluted can be suppressed.

[0106] The complex according to the embodiment further contains glycerin or vegetable oil. This configuration can increase the flexibility of the composite, thereby improving the texture of the composite.

[0107] In the composite according to the embodiment, the mycelia contain chitin, and the binder is bonded to the mycelia via an amide bond. With this configuration, the mechanical strength of the composite can be particularly increased.

[0108] Furthermore, the method for producing a composite according to the embodiment includes a hydrolysis step S102, a binding step S104, and a cross-linking step S106. In the hydrolysis step S102, a sheet containing mycelia is subjected to a hydrolysis treatment. In the binding step S104, the hydrolyzed sheet is brought into contact with a binder containing two or more carboxy groups per molecule to bind the sheet and the binder. In the cross-linking step S106, the sheet to which the binder has been bound is brought into contact with a metal cation to ionically cross-link the carboxy groups together via the metal cation, thereby obtaining a composite.

[0109] According to this configuration, a composite body having excellent mechanical strength and moisture resistance and a good texture can be produced.

[0110] The composite and the method for producing the composite of the present invention have been described above based on preferred embodiments, but the present invention is not limited thereto. For example, the composite of the present invention may be one in which each part of the embodiment is replaced with any component having the same function, or one in which any component is added to the embodiment.

[0111] Furthermore, the method for producing the composite of the present invention may be one in which any step for any purpose is added to the above-described embodiment. [Example]

[0112] Next, specific examples of the present invention will be described. 4. Complex Preparation Example 1 First, 1 g of a sheet containing mycelia was subjected to hydrolysis treatment. The hydrolysis treatment involved immersing the sheet in 100 mL of an alkaline solution at 100° C. for 4 hours. The alkaline solution used was a sodium hydroxide aqueous solution with a concentration of 30% by mass.

[0113] Next, 1 g of sodium alginate as a binder was dissolved in 200 mL of pure water to prepare an aqueous sodium alginate solution.

[0114] Next, the hydrolyzed sheet was sprayed evenly with an aqueous sodium alginate solution to allow it to penetrate, and then placed in a thermostatic chamber and heated at 100°C until it was dry.

[0115] Next, 7.5 mg of calcium chloride, which is a salt containing a metal cation, was dissolved in 30 mL of pure water to prepare an aqueous calcium chloride solution.

[0116] Next, the calcium chloride aqueous solution was uniformly sprayed onto the sheet that had been permeated with the sodium alginate aqueous solution, and the sheet was then placed in a thermostatic chamber and heated at 100°C until it was dry. In this manner, the composite of Example 1 was obtained.

[0117] 4.2. Examples 2 to 21 and Comparative Examples 1 to 4 The composites of Examples 2 to 21 and Comparative Examples 1 to 4 were obtained in the same manner as in Example 1, except that the production conditions for the composites were changed as shown in Figure 2 (Table 1), Figure 3 (Table 2), or Figure 4 (Table 3). Details of the components used in producing the composites are as follows.

[0118] Hyphae (shiitake mushroom, average diameter 3.0 μm, average length 0.1 mm) Hyphae (Polyporus polyporus, average diameter 5.0 μm, average length 0.5 mm) Fiber (cellulose, average diameter 30 μm, average length 1.0 mm)

[0119] 5. Evaluation of the Complex 5.1. Tensile index First, the composite was punched out to prepare test specimens. Next, a tensile property test was performed on the test specimens in accordance with JIS P 8113:2006 using an AUTOGRAPH AGC-X 500N (manufactured by Shimadzu Corporation) to determine the tensile index. The determined values ​​were then evaluated in accordance with the following evaluation criteria. Note that the "reference value" in the evaluation criteria is the tensile index measured for the composite of Comparative Example 4. The evaluation results are shown in the tables.

[0120] A: 150% or more of the standard value B: 125% or more and less than 150% of the standard value C: 100% or more and less than 125% of the standard value D: Less than 100% of the standard value

[0121] 5.2.Moisture resistance First, the composite was cut into a rectangular parallelepiped shape measuring 2 cm x 1 cm x 1 cm to prepare a test specimen. An aluminum plate was placed inside a thermo-humidistat chamber, and the test specimen was placed at each of its four corners. An 800 g aluminum plate was placed on top of the aluminum plate, applying a pressure of 0.01 MPa. After measuring the initial gap between the aluminum plates, the chamber was heated and humidified to 60°C and 90% RH. After 120 hours, the gap between the aluminum plates was measured again, and the displacement rate from the initial gap (compression creep rate) was calculated. The calculated values ​​were then evaluated according to the following evaluation criteria. The evaluation results are shown in the tables.

[0122] A: Compressive creep rate is less than 5% B: Compression creep rate is 5% or more but less than 10% C: Compression creep rate is 10% or more but less than 20% D: Compression creep rate is 20% or more

[0123] 5.3.Texture A sensory evaluation of the composite was conducted by a panel of 10 evaluators. The sensory evaluation was conducted in accordance with the ranking method for sensory evaluation analysis in JIS Z 9080:2004. Specifically, the 10 panelists evaluated the tactile feel of the surface of the composite in accordance with the 9-point preference scale specified in JIS Z 9080:2004. Note that tactile feel particularly refers to the degree of smoothness and pleasant feel to the touch. The obtained preference scale was then evaluated in accordance with the following evaluation criteria. The evaluation results are shown in the tables. Note that on the 9-point preference scale, 9 represents the most pleasant and 1 represents the most unpleasant.

[0124] A: A preference scale of 8 to 9 B: Preference scale score is 6-7 C: Preference scale score is 4-5 D: Preference scale is 1-3

[0125] 5.4. Discussion The evaluation results shown in Figure 2 (Table 1), Figure 3 (Table 2) and Figure 4 (Table 3) reveal the following.

[0126] By incorporating mushroom mycelium, a binder, and divalent or higher metal cations, a composite with excellent mechanical strength, moisture resistance, and texture was realized. In particular, it was found that adding an appropriate amount of mushroom mycelium could improve the texture of the composite. In particular, it was found that the moisture resistance of the composite could be improved by adding an appropriate amount of divalent or higher metal cations. [Explanation of symbols]

[0127] S102 Hydrolysis process S104 Binding process S106 Crosslinking process

Claims

1. Mushroom mycelium and A binder containing two or more carboxyl groups per molecule and binding to the mycelium; a divalent or higher metal cation; and A complex characterized in that the carboxy groups are ionically crosslinked with each other via the metal cation.

2. 10. The composite of claim 1 further comprising fibers.

3. 3. The composite of claim 2, wherein the fibers comprise cellulose.

4. 3. The composite according to claim 1, wherein the metal cation is an ion of at least one metal element selected from the group consisting of Ca, Mg, Ba, Cu, Fe, Al, and Zn.

5. The composite according to claim 1 or 2, wherein the binder contains a polycarboxylic acid or a polycarboxylic acid salt.

6. The composite according to claim 1 or 2, wherein the content of the binder is 1.5% by mass or more and 80.0% by mass or less.

7. When 10 mg of the sample is immersed in 10 mL of a 30% by mass aqueous solution of sodium hydroxide, the concentration of the eluted metal cations is 3×10 －６ mol / L or more 170×10 －６ 3. The complex according to claim 1 or 2, wherein the concentration is 0.01 mol / L or less.

8. 3. The complex according to claim 1 or 2, further comprising glycerin or vegetable oil.

9. the mycelium contains chitin; The complex according to claim 1 or 2, wherein the binder is bonded to the mycelium by an amide bond.

10. A method for producing the composite of claim 1, comprising: a step of subjecting the sheet containing the mycelia to hydrolysis treatment; a step of contacting the sheet that has been subjected to the hydrolysis treatment with the binder containing two or more carboxy groups per molecule to bind the sheet and the binder; a step of contacting the sheet to which the binder is bound with the metal cations and ionically cross-linking the carboxy groups with each other via the metal cations to obtain the composite; A method for producing a composite, comprising:

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