Mycelium structure

Abstract

Provided is a mycelium structure having water resistance and wear resistance and excellent flexibility. This mycelium structure (100) is provided with: a mycelium material (10) comprising a base part (11) having mycelia and a polylactic acid-permeable layer (12) in which polylactic acid permeates into the mycelia; and a polylactic acid coating layer (20) that is provided on the surface of the polylactic acid permeable layer (12) and is thicker than the polylactic acid permeable layer (12). The thickness of the polylactic acid coating layer (20) is preferably from 5.0 [mu] m to 100.0 [mu] m (inclusive). The thickness of the polylactic acid permeable layer (12) is preferably more than 0.0 [mu] m and not more than 30.0 [mu] m. In addition, the polylactic acid is preferably a biodegradable polylactic acid. In addition, the mycelium material (10) preferably further comprises fibers.

Description

Technical Field

[0001] This invention relates to a mycelial structure. Background Technology

[0002] In recent years, as products with low environmental impact, the market has demanded products using natural raw materials. For example, Patent Document 1 discloses a fungal material whose abrasion resistance and water resistance are improved by infiltrating it with a biodegradable polymer. In this document, the biodegradable polymer is infiltrated deep into the fungal material, which is then dried and further pressurized at high temperature, thereby improving the abrasion resistance and water resistance of the fungal material.

[0003] Patent Document 1: Japanese Patent Publication No. 2022-505495

[0004] However, if the polymer is allowed to penetrate deep into the mycelium and pressure is applied at high temperature, the abrasion resistance and water resistance of the fungal material are improved. On the other hand, the material itself becomes harder and its flexibility decreases.

[0005] Therefore, there is a requirement to provide a mycelial structure that is water-resistant, abrasion-resistant, and has excellent flexibility. Summary of the Invention

[0006] The mycelial structure involved in the application examples of the present invention has:

[0007] Mycelial material, consisting of a base with mycelia and a polylactic acid permeated layer infiltrated with polylactic acid within the mycelia; and

[0008] A polylactic acid coating is disposed on the surface of the polylactic acid permeable layer and is thicker than the polylactic acid permeable layer. Attached Figure Description

[0009] Figure 1 This is a schematic longitudinal sectional view of the mycelial structure involved in the embodiment.

[0010] Figure 2 This is a process diagram illustrating the structure of the method for manufacturing the mycelial structure involved in the embodiment.

[0011] Figure 3 Table 1 shows the mycelial structure of each embodiment and each comparative example, as well as the evaluation results of the mycelial structure.

[0012] Explanation of reference numerals in the attached figures

[0013] 10: Mycelial material; 11: Base; 12: Polylactic acid permeation layer; 20: Polylactic acid coating; 100: Mycelial structure; S102: Mycelial preparation process; S104: Coating process; S106: Drying process. Detailed Implementation

[0014] The mycelial structure of the present invention will now be described in detail based on the preferred embodiments shown in the accompanying drawings.

[0015] [1] Mycelial structure

[0016] First, the mycelial structure involved in the implementation method will be described.

[0017] Figure 1 This is a schematic longitudinal sectional view of the mycelial structure involved in the embodiment.

[0018] like Figure 1 As shown, the mycelial structure 100 includes: a mycelial material 10, which is composed of a base 11 having mycelia and a polylactic acid permeation layer 12 in which polylactic acid is permeated in the mycelia; and a polylactic acid coating 20, which is disposed on the surface of the polylactic acid permeation layer 12 and is thicker than the polylactic acid permeation layer 12.

[0019] Based on this structure, a mycelial structure 100 with excellent wear resistance, water resistance, and flexibility can be obtained.

[0020] More specifically, by using a polylactic acid permeation layer 12 and a polylactic acid coating 20 disposed on the surface of the polylactic acid permeation layer 12, the mycelial structure 100 exhibits excellent wear resistance and water resistance. Furthermore, by making the polylactic acid coating 20 thicker than the polylactic acid permeation layer 12, the mycelial structure 100 exhibits excellent flexibility.

[0021] [1-1] Mycelial material

[0022] The mycelial material 10 is composed of a base 11 and a polylactic acid permeated layer 12. In the mycelial material 10, the portion that is not permeated with polylactic acid (described later) is the base 11, and the portion that is permeated with polylactic acid is the polylactic acid permeated layer 12.

[0023] [1-1-1] Components contained in mycelial materials

[0024] Mycelial material 10 contains at least mushroom mycelia.

[0025] [1-1-1-1] Mycelium of mushrooms

[0026] The mycelium of mushrooms is a fibrous structure that makes up the mycelium of mushrooms. As for the types of mushrooms, there are no specific limitations. Examples include *Agaricus arvensis*, *Agrocybebrasiliensis*, *Amylomyces rouxii*, species of *Amylomyces*, *Armillaria mellea*, *Aspergillus nidulans*, *Aspergillus niger*, *Aspergillus oryzae*, *Ceriporia lacerata*, *Coprinus coatus*, *Fibroporia vaillantii*, *Fistulina hepatica*, *Flammulina velutipes*, *Fomitopsis officinalis*, *Ganoderma sessile*, *Ganoderma tsugae*, and *Ganoderma*. lucidum, Hericium erinaceus, Hypholoma capnoides, Hypholoma sublaterium, Inonotus obliquus, Lactarius chrysorrheus, Macrolepidota procera, Morchella angusticeps, Myceliophthora thermophila, Neurospora crassa, Penicillium camembertii, Penicillium chrysogenum, Penicillium rubens, Phycomyces blakesleeanus, Pleurotus djamor, Pleurotus ostreatus, Polyporus squamosus, Psathyrella aquatica, Rhizopus microspores, Rhizopus oryzae, Schizophyllum*Streptomyces venezuelae*, *Stropharia rugosoannulata*, *Thielavia terrestris*, *Ustilago maydis*, *Lentinula*, *Meripilus*, *Grifola*, *Leucopaxillus*, *Fomitopsis*, *Tricholoma*, etc.

[0027] Mycelium is a collection of mycelia from multiple mushrooms. In this invention, in addition to mycelium formed from the growth of mushroom mycelia, mycelium formed by artificially aggregating mushroom mycelia is also referred to as "mycelium". It should be noted that in the following description, mushroom mycelia will also be simply referred to as "mycelia".

[0028] The average diameter of the hyphae is preferably set to be smaller than the average diameter of the fibers (fibers other than hyphae) described later. This makes it easier to impart a smooth texture derived from the hyphae to the mycelial structure 100.

[0029] The average diameter of the hyphae is not particularly limited, but is preferably 0.1 μm or more and 10.0 μm or less, more preferably 0.3 μm or more and 5.0 μm or less. If the average diameter of the hyphae is within the range described above, the texture of the hyphal structure 100 can be particularly improved.

[0030] It should be noted that the average diameter of the hyphae was measured as follows.

[0031] First, the mycelial structure is magnified 100 times to capture an image containing more than 100 hyphae. Next, images of at least 10 hyphae are randomly selected, and the width of each image is measured. Then, the average of the measurements is taken as the average diameter of the hyphae. It should be noted that the average diameter of the fibers (fibers other than hyphae), described later, is also measured in the same way.

[0032] The average length of the hyphae is not particularly limited, but is preferably 0.001 mm or more and 3.0 mm or less, more preferably 0.010 mm or more and 2.0 mm or less, and even more preferably 0.050 mm or more and 1.0 mm or less. If the average length of the hyphae is within this range, then, for example, when the mycelial structure 100 is formed into a sheet shape, the hyphae are oriented along the surface of the mycelial structure 100, and the hyphae are moderately intertwined with each other. This, in turn, can particularly improve the texture of the mycelial structure 100.

[0033] It should be noted that the average length of the hyphae was measured as follows.

[0034] First, the mycelial structure is magnified 100° to capture an image containing more than 100 hyphae. Next, images of at least 10 hyphae are randomly selected, and the maximum achievable length within each image is measured. Then, the average of these measurements is taken as the average length of the hyphae. It should be noted that the average length of the fibers (fibers other than hyphae), described later, is also measured in the same way.

[0035] The hyphae preferably contain chitin. Chitin is included as a component of the cell wall constituting the hyphae. Chitin is a high-molecular-weight polysaccharide with N-acetylglucosamine, which has acetamide groups attached to glucose, as its structural unit. Because chitin has hydroxyl groups, the hyphae are easily cross-linked by the cross-linking agent described later in order to impart strength. As a result, the abrasion resistance and water resistance of the hyphal structure 100 are improved.

[0036] [1-1-1-2] Fibers other than hyphae

[0037] The mycelial material 10 may also include fibers other than mycelia (hereinafter referred to as "fibers"). This can further improve the wear resistance and water resistance of the mycelial structure 100.

[0038] As a fiber, there are no particular limitations, and a wide range of fiber materials can be used. Examples of fibers include natural fibers such as animal fibers and plant fibers, organic fibers, inorganic fibers, and chemical fibers such as organic-inorganic composite fibers. Specifically, examples include cellulose, silk, wool, cotton, hemp, kenaf, flax, ramie, jute, Manila hemp, sisal, coniferous trees, and broadleaf trees. These can be used alone or in appropriate blends. Additionally, they can also be used as refined, regenerated fibers.

[0039] Examples of raw materials for fibers include waste paper and old cloth, and materials containing at least one of the aforementioned fibers can be used. Furthermore, various surface treatments can be applied to the fibers. The fiber material can be a pure substance or a material containing multiple components such as impurities, additives, and other ingredients.

[0040] Among these, fibers containing cellulose are more preferred. Cellulose contains a large number of hydroxyl groups in its molecular structure. Therefore, when using the crosslinking agent described later, it is easy to react with the crosslinking agent, which can easily improve the wear resistance and water resistance of the mycelial structure 100.

[0041] The average diameter of the fibers is not particularly limited, but it is preferably thicker than the average diameter of the mycelium. Specifically, it is preferably 1.0 μm or more and 100.0 μm or less, more preferably 3.0 μm or more and 50.0 μm or less. If the average diameter of the fibers is within the range described above, the wear resistance of the mycelial structure 100 can be particularly improved.

[0042] The average length of the fibers is not particularly limited, but is preferably 0.001 mm or more and 5.0 mm or less, more preferably 0.002 mm or more and 3.0 mm or less, and even more preferably 0.003 mm or more and 2.0 mm or less. If the average length of the fibers is within the above range, then, for example, the fibers are oriented along the surface of the mycelial structure 100, and the fibers are moderately intertwined with each other. This, in turn, can particularly improve the wear resistance of the mycelial structure 100.

[0043] [1-1-1-3] Starch

[0044] The mycelial material 10 may also contain starch. For example, after impregnating the mycelium with a starch solution, the mycelium can be covered with starch by evaporating the water. This further improves the wear resistance of the mycelial structure 100.

[0045] Starch is a molecule composed of multiple α-glucose molecules polymerized through glycosidic bonds. Starch can be a linear molecule or contain branched chains. Various plant-derived starches can be used as starch. More specifically, starches derived from grains such as corn, wheat, and rice; legumes such as broad beans, mung beans, and red beans; tubers such as potatoes, sweet potatoes, and cassava; wild grasses such as ferns and kudzu; and coconuts such as sago palms can be used.

[0046] Starch can be processed starch. Examples of processed starches include acetylated adipic acid cross-linked starch, acetylated starch, oxidized starch, sodium octenyl succinate starch, hydroxypropyl starch, hydroxypropylated phosphoric acid cross-linked starch, phosphorylated starch, phosphate-esterified phosphoric acid cross-linked starch, urea-phosphorylated esterified starch, sodium starch glycolate, and high amylose corn starch. Additionally, starch can also be modified starch. Examples of modified starches include starches obtained through processing or modification of starch; specifically, dextrin can be an example.

[0047] [1-1-1-4] Plasticizer

[0048] The mycelial material 10 may also contain plasticizers. Examples of plasticizers include sugar alcohols, oils, adipate-based plasticizers, phthalate-based plasticizers, trimellitate-based plasticizers, polyester-based plasticizers, (meth)acrylate polymers, ethylene-based copolymer elastomers, chlorinated polyethylene (CPE), (meth)acrylate resins (PMMA), polystyrene resins (PS), polyvinyl acetate resins (PVAc), acrylonitrile-butadiene rubber (NBR), and styrene-butadiene rubber (SBR).

[0049] Examples of sugar alcohols include maltitol, lactitol, butylitol, pentitol, hexatol, erythritol, sorbitol, xylitol, mannitol, and glycerol.

[0050] The mycelial material 10 preferably contains at least one of glycerol and oil. This further improves the flexibility of the mycelial structure 100.

[0051] As for glycerol, there are no particular limitations; it can be either natural glycerol or synthetic glycerol.

[0052] Oil refers to a hydrophobic liquid, generally an ester of alcohol and fatty acids. Oils can be derived from plants, animals, or minerals. Examples of plant oils include castor oil, rapeseed oil, soybean oil, coconut oil, flaxseed oil, olive oil, avocado oil, sesame oil, perilla oil, cottonseed oil, safflower oil, corn oil, rice bran oil, camellia oil, and peanut oil. More specifically, examples include epoxidized vegetable oils such as epoxidized soybean oil (ESBO) and epoxidized flaxseed oil (ELSO).

[0053] When the mycelium contains glycerol and oil, its hydrophilicity decreases. Therefore, the penetration of polylactic acid (PLA) into the mycelium (described later) can be inhibited, resulting in a thinner PLA-permeable layer 12. This, in turn, improves the flexibility of the mycelial structure 100.

[0054] The content of plasticizer in the mycelial material 10 is not particularly limited, but is preferably 10.0% by mass or less, more preferably 0.1% by mass or more and 7.0% by mass or less, and even more preferably 0.5% by mass or more and 4.0% by mass or less. Thus, a mycelial structure 100 that balances wear resistance and flexibility can be obtained.

[0055] [1-1-1-5] Other components contained in mycelial materials

[0056] In addition, the mycelial material 10 may also contain other components. Examples of other components include stabilizers, antioxidants, ultraviolet absorbers, lubricants, flame retardants, antistatic agents, colorants, and fillers.

[0057] The content of other components in the mycelial material 10 is not particularly limited, but is preferably 10.0% by mass or less, more preferably 7.0% by mass or less, and even more preferably 5.0% by mass or less.

[0058] [1-1-1-6] Other

[0059] The substances contained in the mycelial material 10 can be cross-linked with each other using a cross-linking agent. The cross-linking agent reacts with the hydroxyl groups contained in the mycelium and fibers by heating. This improves the wear resistance and water resistance of the mycelial structure 100.

[0060] As a crosslinking agent, any organic compound with multiple carboxyl groups is acceptable, without particular limitations. Examples of crosslinking agents include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, and sebacic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid; dicarboxylic acids with hydroxyl groups such as tartaric acid and malic acid; tricarboxylic acids such as citric acid and aconitic acid; and amino acids with multiple carboxyl groups such as aspartic acid and glutamic acid. One or a mixture of two or more of these can be used.

[0061] The mycelial material 10 can also undergo ozone treatment and deacetylation treatment, as well as treatments that alter the chemical bonds of the mycelium using sebacic acid, tannic acid, etc. These treatments can further improve the wear resistance and water resistance of the mycelial structure 100.

[0062] Treatments that improve the wear resistance, water resistance, and flexibility of the mycelial structure 100 can be carried out individually or in combination as appropriate.

[0063] [1-1-2] Base

[0064] The base 11 is the portion of the mycelial material 10 that is not permeated with polylactic acid (PLA), which will be described later. The base 11 supports the PLA-permeated layer 12 and the PLA coating 20, which will be described later.

[0065] The base 11 may also contain components other than those described in [1-1-1]. For example, after the mycelial structure 100 is manufactured, it may also contain polylactic acid or the like that detached from the polylactic acid permeation layer 12 described later.

[0066] The content of components other than those described in [1-1-1] in the base 11 is not particularly limited, but is preferably 10.0% by mass or less, more preferably 7.0% by mass or less, and even more preferably 5.0% by mass or less.

[0067] [1-1-3] Polylactic acid permeation layer

[0068] The polylactic acid (PLA) permeation layer 12 is the portion of the mycelium material 10 that permeates into the mycelium. PLA permeation into the mycelium refers to the presence of PLA within the mycelial mass formed by the aggregation of mycelia. The PLA permeation layer 12 provides excellent wear resistance and water resistance to the mycelial structure 100. Furthermore, since the PLA permeation layer 12 is located between the base 11 and the PLA coating 20 (described later), it also serves to connect and fix the two together.

[0069] Because polylactic acid permeates the polylactic acid permeation layer 12, it has higher rigidity compared to the base 11. Therefore, to improve the flexibility of the mycelial structure 100, it is preferable that the thickness of the polylactic acid permeation layer 12 is thinner. Thus, the thickness of the polylactic acid permeation layer 12 is preferably more than 0.0 μm and less than 30.0 μm, more preferably more than 0.5 μm and less than 20.0 μm, and even more preferably more than 1.0 μm and less than 10.0 μm. This improves the wear resistance and water resistance of the mycelial structure 100 and enhances its flexibility.

[0070] It should be noted that the thickness of the polylactic acid permeation layer 12 was determined by photographing the cross-sectional structure of the mycelial structure 100 using a scanning electron microscope. Similarly, the thicknesses of the layers described later were also measured.

[0071] The polylactic acid in the polylactic acid permeation layer 12 is preferably biodegradable polylactic acid. Therefore, the environmental impact can be reduced through the carbon neutrality of the raw materials.

[0072] As a raw material for biodegradable polylactic acid, it is possible to use raw materials that are mainly derived from various plant starches. More specifically, it is possible to use starches derived from corn, sugarcane, potatoes, wheat, etc.

[0073] [1-2] Polylactic acid coating

[0074] A polylactic acid coating 20 is disposed on the surface of the polylactic acid permeation layer 12 and contains at least polylactic acid. Therefore, the polylactic acid coating 20 can improve the wear resistance and water resistance of the mycelial structure 100.

[0075] The thickness of the polylactic acid coating 20 is preferably 5.0 μm or more and 100.0 μm or less, more preferably 30.0 μm or more and 95.0 μm or less, and even more preferably 60.0 μm or more and 90.0 μm or less. Thus, the polylactic acid permeation layer 12 can further improve the wear resistance and water resistance of the mycelial structure 100, and also enhance its flexibility.

[0076] The polylactic acid coating 20 is thicker than the polylactic acid permeation layer 12. As a result, the thickness of the highly rigid polylactic acid permeation layer 12 is reduced, which can balance the flexibility, abrasion resistance and water resistance of the mycelial structure 100.

[0077] [1-3] Applications of mycelial structure

[0078] The mycelial structure 100 can be shaped into various forms depending on its intended use. More specifically, it can be shaped into sheets, boards, meshes, etc. Specific examples of its uses include paper, non-woven fabrics, wallpaper, wrapping paper, colored paper, drawing paper, recording media, decorative sheets, fiberboard, filters, liquid absorbent materials, sound absorbers, cushioning materials, mats, etc.

[0079] The mycelial structure 100 described in this embodiment is particularly useful as a natural raw material, such as a leather substitute (alternative leather), due to its excellent wear resistance, water resistance, and softness.

[0080] [1-4] Others

[0081] In the stress-strain curve representing the relationship between stress (MPa) applied by a tensile test and strain (%), the maximum strain in the elastic region of the mycelial structure 100 according to this embodiment is preferably 4.0% or more and 40.0% or less, more preferably 5.0% or more and 30.0% or less, and even more preferably 7.0% or more and 25.0% or less. This structure significantly improves the flexibility of the mycelial structure 100.

[0082] In tensile tests, for example, the Autograph AGS-5kNX (manufactured by Shimadzu Corporation) can be used.

[0083] Regarding the components described in [1-1-1], the conditions in the base 11 and the polylactic acid permeation layer 12 may be different or the same.

[0084] [2] Method for manufacturing mycelial structures

[0085] Next, an example of the manufacturing method of the aforementioned mycelial structure 100 will be described.

[0086] Figure 2 This is a process diagram illustrating the structure of the method for manufacturing the mycelial structure involved in the embodiment.

[0087] Figure 2 The method for manufacturing the mycelial structure 100 shown includes: a mycelial preparation step S102 for preparing mycelia; a coating step S104 for coating the mycelia with a polylactic acid coating agent; and a drying step S106 for drying the coated polylactic acid coating agent.

[0088] [2-1] Mycelium preparation process

[0089] In the mycelium preparation step S102, mycelium containing mycelia is first prepared. Mycelium is formed, for example, by collecting multiple mycelia and shaping and forming them into sheets. It should be noted that the mycelium can be flat or shaped into a predetermined shape. The mycelia can be the defibrinated product of mushroom mycelium. Therefore, the shape of the mushroom mycelium before defibrination is not limited, and the mycelium can be shaped into a desired shape. In the defibrination of mushroom mycelium, for example, a method of imparting mechanical energy can be used. In particular, by using a defibrination machine, the mushroom mycelium can be defibrinated while suppressing significant damage to the mycelium, thus obtaining mycelia. The defibrination method can be a wet method, but a dry method is preferred. A dry method refers to a method of defibrination carried out in a gaseous environment, such as air, rather than in a liquid such as water. In the defibrination machine, an impeller mill capable of dry defibrination is preferred.

[0090] Mycelium can also be formed by mixing mycelium, starch, plasticizer, cross-linking agent, and fiber, and then heating the mixture. In this case, various mixers are used during mixing. Examples of mixers include mechanical mixers, air jet mixers, and ultrasonic mixers. It should be noted that the timing of mixing the above components can be the same for each component or different for each component. For example, two or more components can be mixed simultaneously, or the components can be mixed sequentially.

[0091] In addition, mycelium that has undergone treatment to improve abrasion resistance, water resistance, and softness can also be prepared. Examples of treatments to improve abrasion resistance, water resistance, and softness include, for example, mixing with fibers, impregnation with starch solution, impregnation with solution containing at least one of glycerol and oil, addition of crosslinking agent, and ozone treatment.

[0092] It should be noted that cultured mycelium can also be used as the mycelium. If the inoculum of mycelium is inoculated into a culture medium for cultivation, mycelium that grows and spreads throughout the entire culture medium can be obtained.

[0093] The culture medium can be a solid culture medium or a liquid culture medium.

[0094] The culture medium can also contain components that improve abrasion resistance, water resistance, and flexibility. Examples of components that improve abrasion resistance, water resistance, and flexibility, as mentioned above, include starch, plasticizers, cross-linking agents, and fibers. In addition to these components, the culture medium may also contain nutrients necessary for the mycelial proliferation of mushrooms, gelling agents, etc. Alternatively, starch can be used as a nutrient component.

[0095] In the case of solid culture media, it is preferable to use media that are formed into sheets, thereby simplifying or eliminating secondary processing and enabling efficient production of sheet-like mycelia. Liquid culture media, on the other hand, are formed by dispersing starch, plasticizers, cross-linking agents, fibers, etc., in a dispersion medium such as water. When using liquid culture media, because it is liquid, the management and handling of the medium are easier. Furthermore, in liquid culture media, since stirring and other operations can be performed, it is easier to achieve homogenization and high-speed cultivation.

[0096] The culture conditions, such as culture temperature, culture time, and humidity, can be appropriately set according to the type of mycelium and culture medium.

[0097] In the cultured mycelium, the hyphae are interconnected in a three-dimensional structure. This allows for the imparting of superior flexibility to the mycelial structure.

[0098] The cultured mycelium can also be shaped as needed. In this way, mycelium with the desired shape can be obtained.

[0099] [2-2] Coating process

[0100] Next, in the coating process S104, a polylactic acid (PLA) coating agent is applied to one side of the prepared mycelium to form a uniform film. Thus, a portion of the applied PLA coating agent remains on the surface of the mycelium without penetrating, while a portion penetrates into the mycelium. It should be noted that the PLA coating agent only penetrates a portion of the mycelium, not the entire mycelium. That is, there are portions of the mycelium within which the PLA coating agent has not penetrated.

[0101] Polylactic acid (PLA) coatings are liquids containing PLA. More specifically, a dispersion containing PLA and water is preferred. Any additives may be added to the PLA coating as needed. Examples of additives include condensing agents, antioxidants, stabilizers, and lubricants.

[0102] There are no particular restrictions on the application method of the coating agent; for example, it can be applied by a stick applicator, dipping, scraping, spraying, etc.

[0103] [2-3] Drying process

[0104] In drying step S106, the mycelium coated with polylactic acid is dried. Drying is carried out under atmospheric pressure. Drying is preferably carried out at a temperature above 23°C (room temperature) and below 100°C. The higher the drying temperature, the less flexible the mycelial structure 100 becomes; therefore, it is preferable to carry out drying at the lowest possible temperature.

[0105] If the moisture is evaporated through the drying process S106, the portion of the polylactic acid coating agent that has not penetrated and remains on the surface of the mycelium becomes the polylactic acid coating 20. The portion of the polylactic acid coating agent that has penetrated the mycelium becomes the polylactic acid penetrating layer 12. The portion of the mycelium that has not been penetrated by the polylactic acid coating agent becomes the base 11. The base 11 and the polylactic acid penetrating layer 12 constitute the mycelial material 10.

[0106] The penetration amount of the polylactic acid coating can be adjusted by the drying conditions. That is, the thickness ratio of each layer in the mycelial structure 100 can be adjusted by the drying conditions.

[0107] For example, the shorter the time from applying the polylactic acid (PLA) coating to the start of drying, the shorter the time it takes for the PLA coating to penetrate into the mycelium. Therefore, the amount of PLA penetrating into the mycelium decreases. Consequently, the PLA penetration layer 12 becomes thinner, and the PLA coating layer 20 becomes thicker.

[0108] [3] The effects of the above-described implementation method

[0109] As described above, the mycelial structure involved in the embodiment includes: a mycelial material consisting of a base having mycelia and a polylactic acid permeation layer in which polylactic acid is permeated in the mycelia; and a polylactic acid coating disposed on the surface of the polylactic acid permeation layer and being thicker than the polylactic acid permeation layer.

[0110] Based on this structure, a mycelial structure with excellent wear resistance, water resistance, and flexibility can be obtained.

[0111] Furthermore, in the mycelial structure described in the embodiment, the thickness of the polylactic acid coating is preferably 5.0 μm or more and 100.0 μm or less.

[0112] This structure improves the wear resistance and water resistance of the mycelium structure, and also enhances its flexibility.

[0113] Furthermore, in the mycelial structure described in the embodiment, the thickness of the polylactic acid permeation layer is preferably greater than 0.0 μm and less than 30.0 μm.

[0114] This structure improves the wear resistance and water resistance of the mycelium structure, and also enhances its flexibility.

[0115] Furthermore, in the mycelial structure involved in the above embodiments, polylactic acid is preferably biodegradable polylactic acid.

[0116] Based on this structure, the environmental impact can be reduced through the carbon neutrality of the raw materials in the mycelial structure.

[0117] In addition, in the mycelial structure involved in the above embodiments, the mycelial material preferably also includes fibers.

[0118] This structure allows for further improvement in the wear resistance and water resistance of the mycelium structure.

[0119] Furthermore, in the mycelial structure involved in the above embodiments, the mycelial material preferably includes at least one of glycerol and oil.

[0120] This structure allows for a further improvement in the flexibility of the mycelial structure.

[0121] Furthermore, in the mycelial structure described in the embodiment, it is preferable that the maximum strain in the elastic region is 4.0% or more and 40.0% or less in the stress-strain curve representing the relationship between the stress (MPa) applied by the tensile test and the strain (%) at that time.

[0122] This structure can significantly improve the flexibility of the mycelial structure.

[0123] In addition, in the mycelial structure involved in the above embodiments, the mycelial material may also include mycelium composed of mycelia connected in a three-dimensional shape.

[0124] Based on this structure, by connecting the hyphae to each other in a three-dimensional shape, it is possible to impart superior flexibility to the hyphal structure.

[0125] In addition, in the mycelial structure involved in the above embodiments, the mycelial material may also include defibrinated mycelia.

[0126] Based on this structure, the mycelium of the mushroom can be shaped into the desired shape, regardless of its original shape before defibrination.

[0127] The mycelial structure of the present invention has been described above based on preferred embodiments, but the present invention is not limited thereto. For example, the mycelial structure involved in the present invention may be a structure in which each part of the described embodiments is replaced with any structure having the same function, or it may be a structure in which any structure is added to the described embodiments.

[0128] Example

[0129] Next, specific embodiments of the present invention will be described, but the present invention is not limited thereto. In the processing and measurement in the following embodiments, the measurements were performed at room temperature (23°C) unless otherwise specified.

[0130] [4] Fabrication of mycelial structure

[0131] [4-1] Example 1

[0132] First, the mycelium obtained from the cultured strain (Ganoderma lucidum) was treated to enhance its abrasion resistance and water resistance. As part of this treatment, the mycelium was immersed in a starch solution at room temperature for 160 minutes, then removed and heated at 100°C to evaporate the water. The starch solution used was a 20% by mass aqueous starch solution.

[0133] Next, the mycelium, after being treated to improve abrasion resistance and water resistance, underwent a softening treatment. As a softening treatment, the mycelium was immersed in a glycerol-containing solution at room temperature. After the glycerol was incorporated into the mycelium, it was heated to allow the moisture to evaporate. The glycerol solution used was a 20% by mass solution.

[0134] Next, a thin, even coating of polylactic acid (PLA) was applied to one side of the mycelium that had undergone a softening treatment, allowing it to penetrate. A rod coater was used for the application. A dispersion containing PLA and water was used as the PLA coating agent.

[0135] Then, the mycelium coated with polylactic acid coating was placed in a constant temperature bath and dried at 80°C. As described above, the mycelium structure of Example 1 was obtained.

[0136] [4-2] Examples 2-4 and Comparative Examples 1-3

[0137] In addition to changing the manufacturing conditions of mycelial structure to, for example Figure 3 Except as shown in Table 1, the mycelial structures of Examples 2-5 and Comparative Examples 1-3 were obtained in the same manner as in Example 1. It should be noted that the treatment to impart abrasion resistance, water resistance and flexibility to the mycelium was carried out only in Example 5.

[0138] [5] Evaluation of mycelial structure

[0139] [5-1] Water resistance • Abrasion resistance

[0140] First, test pieces were prepared by punching out the mycelial structure. Next, a white cotton cloth for friction was moistened with water to approximately 100% by mass relative to the cloth. Then, using an AB-301 vibration-type friction fastness testing machine (manufactured by Tester Sangyo Co., Ltd.), the white cotton cloth mounted on a friction element was rubbed against the test piece under a load of 0.067 MPa. The number of times the test piece broke due to friction was measured, and the water resistance and abrasion resistance were evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.

[0141] A: The number of friction cycles until the test piece breaks is over 100.

[0142] B: The number of friction cycles until the test piece breaks is more than 50 but less than 100.

[0143] C: The number of friction cycles until the test piece breaks is more than 10 and less than 49.

[0144] D: The number of friction cycles until the test piece breaks is less than 10.

[0145] [5-2] Softness

[0146] First, test pieces were fabricated by punching the mycelial structure. Next, tensile tests were conducted on the test pieces using an Autograph AGS-5kNX (manufactured by Shimadzu Corporation) based on JIS P 8113:2006. Stress-strain curves showing the relationship between the stress (MPa) applied during the tensile test and the strain (%) were generated to determine the elastic region. Then, the maximum strain in the elastic region was used to evaluate the flexibility according to the following evaluation criteria. A higher maximum strain value in the elastic region indicates better flexibility. The evaluation results are shown in Table 1.

[0147] A: The maximum strain in the elastic region is above 8.0% and below 15.0%.

[0148] B: The maximum strain in the elastic region is greater than 6.0% and less than 8.0%.

[0149] C: The maximum strain in the elastic region is greater than 2.0% and less than 6.0%.

[0150] D: The maximum strain in the elastic region is less than 2.0%.

[0151] As shown in Table 1, the mycelial structures of the various embodiments exhibit wear resistance, water resistance, and excellent flexibility. In contrast, the mycelial structures of the comparative examples did not yield satisfactory results.

Claims

1. A mycelial structure, characterized in that, have: Mycelial material, consisting of a base with mycelia and a polylactic acid permeated layer infiltrated with polylactic acid within the mycelia; and A polylactic acid coating is disposed on the surface of the polylactic acid permeable layer and is thicker than the polylactic acid permeable layer.

2. The mycelial structure according to claim 1, characterized in that, The thickness of the polylactic acid coating is greater than 5.0 μm and less than 100.0 μm.

3. The mycelial structure according to claim 1 or 2, characterized in that, The thickness of the polylactic acid permeable layer is greater than 0.0 μm and less than 30.0 μm.

4. The mycelial structure according to claim 1 or 2, characterized in that, The polylactic acid mentioned is biodegradable polylactic acid.

5. The mycelial structure according to claim 1 or 2, characterized in that, The mycelial material also includes fibers.

6. The mycelial structure according to claim 1 or 2, characterized in that, The mycelial material comprises at least one of glycerol and oil.

7. The mycelial structure according to claim 1 or 2, characterized in that, The mycelial structure is represented in the stress-strain curve, which shows the relationship between the stress applied by the tensile test and the strain at that time. The maximum strain in the elastic region is above 4.0% and below 40.0%. The unit of stress is MPa, and the unit of strain is % (%).

8. The mycelial structure according to claim 1 or 2, characterized in that, The mycelial material comprises mycelia connected in a three-dimensional shape.

9. The mycelial structure according to claim 1 or 2, characterized in that, The mycelial material comprises the mycelium after defibrilation.

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