Aminoacyl sulfonate crosslinking agent and ecological crosslinking method of mycelium pellicle

Abstract

The present application belongs to the field of mycelium leather preparation, and provides an aminoacyl sulfonate crosslinking agent and an ecological crosslinking method of mycelium leather. The structural general formula of the aminoacyl sulfonate crosslinking agent is. The ecological crosslinking method of the mycelium leather comprises pretreatment, crosslinking and post-treatment steps, wherein the operation of the crosslinking step is: adding pretreated mycelium pieces and water into a rotating drum, adding the crosslinking agent, rotating the rotating drum to make the crosslinking agent fully penetrate into the pretreated mycelium pieces; under the condition of rotating the rotating drum, adjusting the pH value and temperature of the bath to make the blocking group of the crosslinking agent unblock to release isocyanate groups, making the crosslinking agent after unblocking of the blocking group and the pretreated mycelium pieces fully chemically crosslink, taking out, squeezing water, and obtaining crosslinked mycelium. The present application can realize chemical crosslinking of mycelium material on the basis of not carrying out deacetylation treatment on the mycelium material, and improve the mechanical properties, fullness and softness of the mycelium leather.

Description

Technical Field

[0001] This invention belongs to the field of mycelial leather preparation, and relates to aminoacylsulfonate crosslinking agents and ecological crosslinking methods for mycelial leather. Background Technology

[0002] Thin sheets of mycelium obtained by culturing fungal strains on solid culture media can be modified to produce leather-like sheet materials. These sheet materials, with their unique advantages of sustainability and biodegradability, can serve as alternatives to animal leather or synthetic leather and are attracting increasing attention.

[0003] To prevent the mycelial material from rotting and deteriorating and to obtain good physical properties, the harvested mycelial material must be chemically modified. Currently, the chemical modification of mycelial materials largely borrows from the tanning concept of animal leather, using vegetable tanning agents (such as tannin), genipin, glutaraldehyde or modified glutaraldehyde, organophosphorus salts, and other cross-linking agents to chemically cross-link the deacetylated mycelial fibers. However, using these cross-linking agents to chemically cross-link mycelial materials still presents some problems. For example, some cross-linking agents release formaldehyde during the cross-linking process, which does not meet the requirements of ecological leather. Furthermore, some cross-linking agents only fill the spaces between the mycelial fibers, resulting in finished mycelial leather that is too stiff, or even lacks flexibility and suppleness, thus reducing its quality and usability.

[0004] Furthermore, fungal mycelia are composed of a network of tubular microfilaments called hyphae. The hyphal cell wall is the main component of the dry matter of fungal mycelia, and the main components of the hyphal cell wall are polysaccharides, primarily including polymers such as chitin, cellulose, dextran, and mannan. Existing cross-linking methods for mycelial materials require first treating the mycelia with a high concentration of alkali to deacetylate the chitin in the mycelial fibers, releasing amino groups. The deacetylated amino groups then react with a cross-linking agent to achieve cross-linking. This alkali treatment process dissolves and removes some polysaccharides from the mycelia, resulting in component loss from the mycelial fibers.

[0005] While chemical cross-linking can regulate the tensile and tear strength of mycelial materials to some extent, the high-concentration alkaline deacetylation process prior to chemical cross-linking causes component loss in the mycelial fibers, which limits the mechanical properties and fullness of the resulting cross-linked mycelial skin. Achieving chemical cross-linking of mycelial materials while minimizing or avoiding mycelial fiber loss, and simultaneously maintaining the mechanical properties, softness, and fullness of the mycelium, is a major technical challenge in this field. Therefore, developing cross-linking agents and methods more suitable for mycelial materials, achieving chemical cross-linking without deacetylation of the mycelial material, and avoiding the generation of harmful chemicals during the cross-linking process, would have a positive impact on improving the mechanical properties and sensory quality of the mycelial skin, and promoting the greening of the mycelial material modification process and end products. Summary of the Invention

[0006] Existing chemical crosslinking agents for mycelial materials mainly use amino groups on the mycelial material as reaction sites. Before chemical crosslinking, the mycelial material needs to be deacetylated to release the amino groups. However, this process results in the loss of components in the mycelial fibers, leading to poor mechanical properties and reduced fullness of the crosslinked mycelial skin. To address this problem, this invention provides an aminoacylsulfonate crosslinking agent and an ecological crosslinking method for mycelial skin, which enables chemical crosslinking of mycelial materials without the need for deacetylation treatment, and improves the mechanical properties, fullness, and softness of the mycelial skin.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0008] An aminoacylsulfonate crosslinking agent, the general structural formula of which is as follows:

[0009] ,

[0010] In the above formula, R is , , or R' is or .

[0011] In the above-mentioned technical solution of aminoacylsulfonate crosslinking agent, , and Of these three groups, This indicates a broken bond, meaning the chemical bond is broken at this point. It is used here to illustrate the three functional groups and the general structural formula. The connection sites of the N atoms on both sides of R, i.e. , and Through the two in its structure respectively The N atoms on both sides of R are connected.

[0012] In the above-mentioned technical solution for aminoacylsulfonate crosslinking agents, the structural formula of the aminoacylsulfonate crosslinking agent is selected from any one of the following structural formulas (I) to (VIII):

[0013] (I),

[0014] (Ⅱ),

[0015] (Ⅲ),

[0016] (Ⅳ),

[0017] (V),

[0018] (VI),

[0019] (VII),

[0020] (VIII)

[0021] In the above-mentioned technical solution for aminoacylsulfonate crosslinking agents, when R' is When n is 2 to 23.

[0022] In the above-mentioned technical solution of aminoacylsulfonate crosslinking agent, the aminoacylsulfonate crosslinking agent is obtained by extending the diisocyanate monomer with a diol chain extender and then capping the isocyanate group of the extended diisocyanate with sodium bisulfite; the diisocyanate monomer is hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate or diphenylmethane diisocyanate, the diisocyanate monomer is preferably an aliphatic diisocyanate, such as hexamethylene diisocyanate and isophorone diisocyanate, the diisocyanate monomer is more preferably hexamethylene diisocyanate; the diol chain extender is ethylene glycol or polyethylene glycol with a molecular weight of 200~1000, that is, the average degree of polymerization of polyethylene glycol n=2~23, preferably the average degree of polymerization of polyethylene glycol n=3~10, and more preferably the average degree of polymerization of polyethylene glycol is 4~8.

[0023] In the above-mentioned technical solution of aminoacylsulfonate crosslinking agent, R in the general formula comes from diisocyanate monomer and R' comes from diol chain extender.

[0024] The above-mentioned aminoacylsulfonate crosslinking agent can be prepared according to existing technology. A feasible method for preparing an aminoacylsulfonate crosslinking agent includes the following steps:

[0025] (1) Chain extension of diisocyanates

[0026] The diisocyanate monomer and the chain extender are dissolved in an organic solvent and allowed to react fully to obtain a chain-extended diisocyanate solution.

[0027] (2) End capping of isocyanate group

[0028] A saturated aqueous solution of sodium bisulfite is thoroughly mixed with an alcoholic dispersant, ethanol, to obtain a capping solution. The capping solution is then added to the chain-extended diisocyanate solution, and the reaction is allowed to proceed until the organic solvent is removed, thus yielding an aqueous solution of the aminoacylsulfonate crosslinking agent.

[0029] In step (1) of the above preparation method, the diisocyanate monomer is hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate or diphenylmethane diisocyanate.

[0030] In step (1) of the above preparation method, the chain extender is ethylene glycol or polyethylene glycol with a molecular weight of 200~1000.

[0031] In step (1) of the above preparation method, the organic solvent is a good solvent for diisocyanate monomers and chain extenders. In actual use, the type of organic solvent can be selected based on factors such as its toxicity and recyclability. Suitable organic solvents are usually any one of toluene, xylene, acetone, dioxane, ethyl acetate, and dimethylformamide.

[0032] In step (1) of the above preparation method, after dissolving the diisocyanate monomer and the chain extender in an organic solvent, the concentration of the chain extender in the resulting solution is preferably 30 v / v% to 35 v / v.

[0033] In step (1) of the above preparation method, the molar ratio of diisocyanate monomer to chain extender is controlled to be (2~2.4):1.

[0034] In step (1) of the above preparation method, the reaction temperature can usually be controlled at 40~90 ℃, and the reaction time can be controlled at 2~7 h. Further, the reaction time is preferably 3.5~4.5 h.

[0035] In step (2) of the above preparation method, the feasible alcohol dispersant can be methanol, ethanol, n-propanol, isopropanol or n-butanol, and the preferred alcohol dispersant is ethanol.

[0036] In step (2) of the above preparation method, the content of dispersant in the sealing liquid is usually 20 wt%~50 wt%.

[0037] In step (2) of the above preparation method, the molar ratio of sodium bisulfite to the isocyanate group of the chain-extended diisocyanate is controlled to be (1.1~1.22):1.

[0038] In step (2) of the above preparation method, the reaction temperature can usually be controlled at 1~10 ℃, and the reaction time can be controlled at 1~2 h.

[0039] Based on the above-mentioned aminoacylsulfonate crosslinking agent, the present invention also provides an ecological crosslinking method for mycelial skin, comprising the following steps:

[0040] (1) Pretreatment

[0041] Take mycelial sheets, slice them evenly, wash them with water, and obtain pretreated mycelial sheets;

[0042] (2) Crosslinking

[0043] Add 100 parts by weight of pretreated mycelial sheets and 100-300 parts by weight of water to a rotating drum, then add the crosslinking agent mentioned above, so that the concentration of the crosslinking agent in the bath is 4 wt%-12 wt%. Rotate the drum to allow the crosslinking agent to fully penetrate into the pretreated mycelial sheets. Under the condition of drum rotation, adjust the pH and temperature of the bath to deseal the end groups of the crosslinking agent and release isocyanate groups, so that the crosslinking agent after the end groups are desealed can fully chemically crosslink with the pretreated mycelial sheets. Remove the sheets, squeeze out the water, and obtain crosslinked mycelium.

[0044] (3) Post-processing

[0045] The cross-linked mycelium obtained in step (2) was plasticized, dried and finished according to standard procedures to obtain mycelium skin.

[0046] In step (2) of the above-mentioned ecological cross-linking method for mycelial skin, it is preferable to adjust the pH of the bath solution to 7.0~9.0 and adjust the temperature of the bath solution to 50~80 ℃, so that the end-capping groups of the cross-linking agent are unsealed and release isocyanate groups.

[0047] In the above-mentioned ecological cross-linking method for mycelial skin, when step (2) adjusts the pH of the bath solution to 7.0~9.0 and the temperature of the bath solution to 50~80 ℃, the end groups of the cross-linking agent are unsealed and release isocyanate groups. The released isocyanate groups will react with a large number of hydroxyl groups on the mycelial fibers. At the same time, under the condition of pH 7.0~9.0, the mycelial fibers will undergo a certain degree of deacetylation and release some amino groups. The released amino groups can also react with isocyanate groups. Unlike the prior art, the above-mentioned ecological cross-linking method for mycelial skin does not require a special deacetylation operation on the pretreated mycelial sheets. The mycelial fibers only undergo a certain degree of deacetylation during the cross-linking process. This is beneficial to effectively reduce the loss of mycelial fiber components caused by the special deacetylation operation, and thus is beneficial to improve the mechanical properties of the mycelial skin.

[0048] In step (2) of the above-mentioned ecological cross-linking method for mycelial skin, after adjusting the pH value of the bath solution to 7.0~9.0 and the temperature of the bath solution to 50~80 ℃, the cross-linking reaction is carried out by rotating the drum for 120~180 min to obtain cross-linked mycelium.

[0049] In step (2) of the above-mentioned ecological cross-linking method for mycelial skin, after adding the cross-linking agent to the drum, the temperature of the bath liquid is controlled at 35~45 ℃ so that the cross-linking agent can be evenly penetrated into the pretreated mycelial sheet.

[0050] In step (2) of the above-mentioned ecological cross-linking method for mycelial skin, after adding the cross-linking agent to the drum, the drum is rotated for 120~180 minutes to allow the cross-linking agent to penetrate evenly into the pretreated mycelial sheet.

[0051] In step (2) of the above-mentioned ecological cross-linking method for mycelial skin, when adjusting the pH value of the bath solution, the pH value of the bath solution is adjusted by adding alkaline substances to the bath solution. Commonly used alkaline substances are sodium carbonate and / or sodium hydroxide.

[0052] In step (2) of the above-mentioned ecological cross-linking method for mycelial skin, it is preferable to control the concentration of the cross-linking agent in the bath solution to be 6 wt%~10 wt%.

[0053] In step (3) of the above-mentioned ecological cross-linking method for mycelial skin, the plasticizing operation can be carried out by referring to the existing plasticizing method for mycelial skin. For example, a feasible plasticizing operation is as follows:

[0054] Add 80-120 parts by weight of water to the drum and heat it to 50-60 ℃. Then add 8-20 parts by weight of plasticizer and rotate the drum to fully disperse the plasticizer in the water. Add 100 parts by weight of the cross-linked mycelium obtained in step (2) and then rotate the drum at 35-50 ℃ until the bath liquid is basically completely absorbed by the cross-linked mycelium. The skin is then exfoliated, and plasticization is completed. In the subsequent drying process, the plasticizer will be deposited between the mycelium fibers.

[0055] In the above plasticizing operation, the plasticizer can be selected by referring to the existing plasticizing method of mycelial skin. For example, the plasticizer can be a modified natural oil product or a mixture of a modified natural oil product and a polyol. Usually, the mass ratio of the modified natural oil product to the polyol is (2~5):1.

[0056] Furthermore, the modified natural oil product is a combination of one or more of the following: sulfated oil, sulfite oil, phosphoric acid oil, and sulfonated oil, obtained by modifying natural animal and vegetable oils. Even further, the modified natural oil product is a combination of one or more of the following: Lipsol BSFR, Lipsol STS, Neoprisol EWK, SYNTHOL CP996, SYNTHOLCU909, and SYNTHOL FF992. The polyol is a combination of one or more of the following: glycerol, ethylene glycol, polyethylene glycol, polypropylene glycol, sorbitol, and polyol esters.

[0057] In step (3) of the above-mentioned ecological cross-linking method for mycelial skin, the drying and finishing mainly include processes such as drying, vibration or tumbling to soften, and surface coating.

[0058] In step (1) of the above-mentioned ecological cross-linking method for mycelial skin, the mycelial sheet refers to a sheet-like mycelium, preferably a sheet-like fungal mycelium. The mycelial sheet can be prepared according to existing technology, typically by transplanting mycelium obtained from liquid fermentation onto a solid culture medium. For example, mycelium obtained from liquid fermentation of Ganoderma lucidum strains can be transplanted onto a solid culture medium for cultivation.

[0059] In the above-mentioned ecological cross-linking method for mycelial skin, it is best to use an intermittent rotation method to rotate the drum, controlling the rotation speed of the drum to be 3~10 rpm, and rotating the drum for 5~10 minutes per hour.

[0060] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0061] 1. This invention provides an aminoacylsulfonate crosslinking agent, primarily used for crosslinking mycelia. This aminoacylsulfonate crosslinking agent is obtained by extending the chain of a diisocyanate monomer with a chain extender, followed by end-capping the isocyanate groups with sodium bisulfite. This crosslinking agent exhibits good water solubility. When using this agent for mycelial crosslinking, the conditions of the bath solution are first controlled to ensure the crosslinking agent, in its end-capped state, uniformly penetrates the pretreated mycelial sheets. After penetration is complete, the pH of the bath solution is increased to 7.0-9.0, and the bath solution is heated, causing the end-capped groups of the crosslinking agent to uncap and release the isocyanate groups. This allows the uncapped crosslinking agent to undergo sufficient chemical crosslinking with the numerous hydroxyl groups and a small amount of amino groups on the mycelial fibers. Compared to existing technologies, the above mycelial crosslinking process only produces water and neutral salts, without generating new harmful chemical substances. This ensures that the prepared mycelial skin does not contain free formaldehyde or other harmful substances, posing no health risk to consumers and causing no environmental pollution, thus promoting the greening of mycelial material modification processes and end products.

[0062] 2. Based on this aminoacylsulfonate crosslinking agent, the present invention also provides an ecological crosslinking method for mycelial skin. This method utilizes the decapping groups of the crosslinking agent to release isocyanate groups, which directly react with a large number of hydroxyl groups on the mycelium, amino groups generated during the partial deacetylation of mycelial fibers, and a small amount of amino groups originally present in the mycelial fibers. This eliminates the need for a dedicated deacetylation operation on the mycelium. On the one hand, this simplifies the crosslinking process of the mycelium. On the other hand, it reduces the dissolution of components in the mycelial fibers by high-concentration alkali during the deacetylation process, thus better preserving the components of the mycelial fibers and effectively avoiding the decline in the mechanical properties of the mycelial skin due to the loss of mycelial fiber components.

[0063] 3. The ecological cross-linking method for mycelial skin described in this invention involves a cross-linking reaction between the aminoacylsulfonate cross-linking agent and mycelial fibers. On one hand, the molecular chain length of the aminoacylsulfonate cross-linking agent can better adapt to the larger spacing between mycelial fibers, thereby ensuring sufficient cross-linking between the mycelial fibers. On the other hand, the appropriate molecular chain length of the aminoacylsulfonate cross-linking agent can solve the problem of limited sliding between mycelial fibers after cross-linking due to the excessively short molecular chains of small molecule cross-linking agents. These two aspects can improve the tensile strength and tear strength of the prepared mycelial skin, and while taking into account mechanical properties, endow the mycelial skin with good fullness and softness. Attached Figure Description

[0064] Figure 1 This is the infrared spectrum of the chain-extended hexamethylene diisocyanate prepared in Example 1.

[0065] Figure 2This is the infrared spectrum of AFS-400 prepared in Example 1.

[0066] Figure 3 This is a photograph of the mycelial skin prepared in Example 2.

[0067] Figure 4 This is a photograph of the mycelial skin prepared in Comparative Example 1.

[0068] Figure 5 This is a photograph of the mycelial skin prepared in Comparative Example 2.

[0069] Figure 6 This is a photograph of the mycelial skin prepared in Comparative Example 3.

[0070] Figure 7 This is a photograph of the mycelial skin prepared using AFS-1 as a crosslinking agent in Example 6.

[0071] Figure 8 This is a photograph of the mycelial skin prepared using AFS-200 as a crosslinking agent in Example 6. Detailed Implementation

[0072] The following examples further illustrate the aminoacylsulfonate crosslinking agent and the ecological crosslinking method for mycelial skin provided by the present invention. It should be noted that the following examples are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above-described invention are still within the scope of protection of the present invention.

[0073] In the following examples and comparative examples, the mycelial sheets refer to sheet-like mycelia. These mycelial sheets were obtained from Tianjin Meikexin Biotechnology Co., Ltd., and were cultured by transplanting mycelia obtained from Ganoderma lucidum strains through liquid fermentation onto a solid culture medium. Lipsol BSFR and Neoprisol EWK are commercial products from Schill+Seilacher GmbH, Germany.

[0074] Example 1

[0075] In this embodiment, the aminoacylsulfonate crosslinking agent is prepared by the following steps:

[0076] (1) Chain extension of diisocyanates

[0077] Hexamethylene diisocyanate monomer and polyethylene glycol 400 (PEG400) were dissolved in acetone at a molar ratio of 2.2:1, so that the concentration of PEG400 was about 35 v / v%. The reaction was carried out at 40~75℃ for 3.5 h. During the reaction, heat was released and the temperature was gradually increased. The temperature was controlled at 40℃ in the early stage of the reaction and at 75℃ in the later stage of the reaction to obtain the chain-extended hexamethylene diisocyanate solution.

[0078] (2) End capping of isocyanate group

[0079] A saturated aqueous solution of sodium bisulfite was thoroughly mixed with ethanol as a dispersant, with the amount of dispersant being 20 wt% of the saturated aqueous solution of sodium bisulfite, to obtain a capping solution. The capping solution was added to the chain-extended hexamethylene diisocyanate solution at a molar ratio of sodium bisulfite to the isocyanate groups (-NCO) of the chain-extended hexamethylene diisocyanate of 1.1:1. The reaction was stirred at 5 °C for 1.5 h, and the organic solvent was removed under vacuum to obtain an aqueous solution of aminoacylsulfonate crosslinking agent (AFS-400). The structural formula of AFS-400 is as follows:

[0080] .

[0081] Figure 1 This is the infrared spectrum of the chain-extended hexamethylene diisocyanate prepared in step (1) of this embodiment. Figure 2 This is the infrared spectrum of AFS-400 prepared in step (2) of this embodiment.

[0082] Figure 1 Middle, 3336 cm -1 The peak at 1717 cm⁻¹ is the absorption peak of the stretching vibration of the -NH- bond. -1 The peak at 1304 cm⁻¹ is a strong absorption peak of C=O in carbamate. -1 The characteristic stretching vibration peak of COC in carbamates appeared at 1528 cm⁻¹. -1 The characteristic vibrational absorption peaks of the NC in the -NH-CO-O- urethane bond appeared at 2257 cm⁻¹, indicating the presence of the urethane bond. Simultaneously, at 2257 cm⁻¹... -1 The presence of absorption peaks indicates that the chain-extended hexamethylene diisocyanate prepared in step (1) still contains isocyanate groups. Figure 2 Middle, 2257 cm -1 The absence of an absorption peak at 1111 cm⁻¹ indicates that the isocyanate group reaction is complete. -1 The characteristic absorption peak of ether bonds appeared at 2970~2870 cm⁻¹. -1The characteristic absorption peaks of the repeating units CH2-CH2O- and -CH2 in polyethers appeared at 3336 cm⁻¹, and at the same time, at 3336 cm⁻¹... -1 An absorption peak for the -NH- bond stretching vibration appeared at 1717 cm⁻¹. -1 A strong absorption peak for C=O in carbamates appeared at 1304 cm⁻¹. -1 The characteristic stretching vibration peak of COC in carbamates appeared at 1528 cm⁻¹. -1 The characteristic absorption peaks of the urethane bond -NH-CO-O- appeared at 1240 cm⁻¹, indicating that AFS-400 still retains urethane groups. -1 The peak at that location is the absorption peak of the sulfonate. The above experimental results confirm that the AFS-400 prepared in this example is indeed a carbamoyl sulfonate.

[0083] Example 2

[0084] In this embodiment, an ecological cross-linking method for mycelial coat is provided, comprising the following steps:

[0085] (1) Pretreatment

[0086] Take mycelial sheets, shave them evenly, and wash them with water to remove water-soluble polysaccharides adhering to the surface of the mycelial sheets and debris generated during the shaving process, thus obtaining pretreated mycelial sheets.

[0087] (2) Crosslinking

[0088] 100 parts by weight of pretreated mycelial sheets and 300 parts by weight of water were added to a rotating drum. Then, an aqueous solution of AFS-400 prepared in Example 1 was added, controlling the concentration of AFS-400 in the bath to 6 wt% and the temperature of the bath to 35 °C. The drum was rotated intermittently at 3 rpm for 120 min (5 min per hour) to promote uniform penetration of AFS-400 into the pretreated mycelial sheets. Under the rotating drum condition, anhydrous sodium carbonate was added to adjust the pH of the bath to 7.5, and the temperature of the bath was adjusted to 65 °C. The drum was rotated intermittently at 3 rpm for 120 min (5 min per hour) to allow AFS-400 to undergo a cross-linking reaction with the pretreated mycelial sheets. The sheets were then removed, the water was squeezed out, and sheet-like cross-linked mycelia were obtained.

[0089] (3) Post-processing

[0090] The post-processing includes plasticizing, drying, and finishing, as detailed below:

[0091] Add 80 parts by weight of water to the drum and heat it to 50 ℃. Then add 12 parts by weight of plasticizer (specifically 4 parts by weight of Lipsol BSFR, 5 parts by weight of Neoprisol EWK and 3 parts by weight of glycerol). Rotate the drum to fully disperse the plasticizer in the water. Add 100 parts by weight of the cross-linked mycelium obtained in step (2). Then rotate the drum intermittently at 3 rpm for 180 min at 50 ℃ (rotate the drum 10 min per hour). At this time, the bath liquid has been basically completely absorbed by the cross-linked mycelium. The skin is formed, plasticization is completed, and then it is dried. During the drying process, the plasticizer will be deposited between the mycelium fibers. Then it is softened by shaking or slapping to obtain the mycelium skin.

[0092] Comparative Example 1

[0093] In this comparative example, glutaraldehyde, a conventional cross-linking agent, was used to cross-link the mycelial skin.

[0094] The operation of this comparative example is basically the same as that of Example 2, except that the crosslinking agent is replaced by glutaraldehyde instead of AFS-400.

[0095] Comparative Example 2

[0096] In this comparative example, the existing conventional cross-linking agent genipin was used to cross-link the mycelial skin.

[0097] The operation of this comparative example is basically the same as that of Example 2, except that the crosslinking agent is replaced by Genipin instead of AFS-400.

[0098] Comparative Example 3

[0099] In this comparative example, following existing methods, a process flow of "first deacetylifying the mycelial sheets, then crosslinking the deacetylated mycelial sheets" was adopted. The crosslinking agent AFS-400 prepared in Example 1 was used to crosslink the mycelial sheets, and the steps are as follows:

[0100] (1) Pretreatment

[0101] Take mycelial sheets, shave them evenly, and wash them with water to remove water-soluble polysaccharides adhering to the surface of the mycelial sheets and debris generated during the shaving process, thus obtaining pretreated mycelial sheets.

[0102] (2) Deacetylation treatment

[0103] 100 parts by weight of pretreated mycelial sheets and 300 parts by weight of 5 wt% sodium hydroxide aqueous solution were added to a rotating drum. The temperature of the bath was controlled at 60 ℃. The drum was rotated intermittently at 3 rpm for 120 min (5 min per hour) to deacetylate the pretreated mycelial sheets. After that, the sheets were washed with water until the wash solution was neutral to obtain deacetylated mycelial sheets.

[0104] The deacetylation process in this step mainly involves deacetylation of chitin in the mycelial fibers to release amino groups, so that the amino groups on the deacetylated mycelial sheets can be chemically cross-linked with the cross-linking agent. However, the deacetylation process will cause some polysaccharide substances in the mycelial sheets to be dissolved and removed, resulting in the loss of components in the mycelial fibers.

[0105] (3) Crosslinking

[0106] 100 parts by weight of deacetylated mycelial sheets and 300 parts by weight of water were added to a rotating drum. Then, an aqueous solution of AFS-400 prepared in Example 1 was added, controlling the concentration of AFS-400 in the bath to 6 wt% and the temperature of the bath to 35°C. The drum was rotated intermittently at 3 rpm for 2 h (5 min per hour) to promote the uniform penetration of AFS-400 into the deacetylated mycelial sheets. Under the rotating drum condition, anhydrous sodium carbonate was added to adjust the pH of the bath to 7.5, and the temperature of the bath was adjusted to 65°C. The drum was rotated intermittently at 3 rpm for 2 h (5 min per hour) to allow AFS-400 to undergo a cross-linking reaction with the deacetylated mycelial sheets. The sheets were then removed, the water was squeezed out, and sheet-like cross-linked mycelia were obtained.

[0107] (4) Post-processing

[0108] The obtained cross-linked mycelium was plasticized, dried and finished according to step (3) of Example 2 to obtain mycelium skin.

[0109] Example 3

[0110] In this embodiment, the tensile strength and tear strength of the mycelial skins prepared in Example 2 and Comparative Examples 1-3 were tested, and sensory evaluation was performed. The results are shown in Table 1.

[0111] Table 1. Tensile strength, tear strength, and sensory evaluation of the mycelial sheaths prepared in Example 2 and Comparative Examples 1-3.

[0112] <![CDATA[Tensile strength (MPa / mm 2 )]]> Tear strength (N / mm) Sensory evaluation Example 2 5.02 9.54 It is light in color, off-white, soft and full to the touch, and has a smooth surface. Comparative Example 1 3.58 6.65 It is pale yellow, soft to the touch, slightly less full, and has a natural surface texture. Comparative Example 2 3.69 5.02 The color is light, the surface is firm, the leather is thin, and the fullness and softness are poor. Comparative Example 3 2.95 5.34 It is slightly yellow in color (compared to the mycelial skin prepared in Example 2), soft to the touch, and lightly foamy.

[0113] Photographs of the mycelial skins prepared in Example 2 and Comparative Examples 1-3 are shown below. Figures 3-6 As shown. Combined with Figures 3-6 As shown in Table 1:

[0114] (1) Compared with the mycelial skin prepared in Example 2, the mycelial skin prepared in Comparative Example 3 showed a significant decrease in tensile strength and tear strength. This is mainly because Comparative Example 3 performed deacetylation treatment on the pretreated mycelial sheet before crosslinking. Although the specific deacetylation treatment step can release a large number of amino groups with higher reactivity with the crosslinking agent, the specific deacetylation treatment process will also cause some polysaccharide substances in the mycelial sheet to be dissolved and removed, resulting in the loss of mycelial fiber components. The loss of mycelial fiber components will reduce the mechanical properties of the mycelial skin.

[0115] In step (3) of Example 2, the main reliance is on the large number of hydroxyl groups in the mycelial fibers, the amino groups produced by partial deacetylation of the mycelial fibers under pH=7.5 conditions, and the cross-linking reaction between the small amount of amino groups originally present in the mycelial fibers and the isocyanate groups of the cross-linking agent AFS-400. Example 2 did not perform a specific deacetylation treatment on the pretreated mycelial sheets, thereby reducing the dissolution of components in the mycelial fibers by the high concentration of alkali during the deacetylation process, better preserving the components of the mycelial fibers, and effectively avoiding the decline in the mechanical properties of the mycelial skin due to component loss.

[0116] (2) Compared with the mycelial skin prepared in Comparative Example 3, the tensile strength of the mycelial skin prepared in Comparative Example 1 and Comparative Example 2 was improved, but the tensile strength was still lower than that of the mycelial skin prepared in Example 2. Meanwhile, the tear strength of the mycelial skin prepared in Comparative Example 2 and 3 was comparable. Although the tear strength of the mycelial skin prepared in Comparative Example 1 was improved, the tear strength was still significantly different from that of the mycelial skin prepared in Example 2. This is mainly because the cross-linking agents glutaraldehyde and genipin used in Comparative Examples 1 and 2 are both small-molecule cross-linking agents. The mycelial fibers have a relatively large spacing and a relatively loose network structure (compared to animal skin collagen fibers). The molecular chains of small-molecule cross-linking agents are too short to ensure sufficient cross-linking between the mycelial fibers. In particular, the cross-linking effect of genipin with mycelial fibers is weak, and it cannot react well with the active groups between the mycelial fibers to produce a strong chemical reaction. Instead, it fills the spaces between the mycelial fibers, thus restricting the free movement of the mycelial fibers. This results in reduced softness of the prepared mycelial skin, making it too tight and stiff, thus lacking fullness and softness. Although glutaraldehyde has a significantly stronger cross-linking ability than genipin, its short molecular chain restricts the movement between mycelial fibers after cross-linking, resulting in slightly poorer fullness of the prepared mycelial skin.

[0117] Example 2 uses AFS-400 as a crosslinking agent to react with pretreated mycelial sheets. On one hand, the molecular chain length of AFS-400 is greater than that of glutaraldehyde and genipin, allowing it to better adapt to the larger spacing between mycelial fibers and ensure sufficient crosslinking. On the other hand, the appropriate molecular chain length of AFS-400 prevents the crosslinked mycelial fibers from being too short, thus maintaining their mobility. These two aspects improve the tensile and tear strength of the prepared mycelial skin, imparting good fullness and softness while maintaining mechanical properties.

[0118] Example 4

[0119] In this embodiment, an aminoacylsulfonate crosslinking agent is prepared. The operation in this embodiment is basically the same as that in Example 1, except that PEG400 in step (1) of Example 1 is replaced with ethylene glycol, and the aqueous solution of the finally prepared aminoacylsulfonate crosslinking agent (AFS-1) is used.

[0120] Example 5

[0121] In this embodiment, an aminoacylsulfonate crosslinking agent is prepared. The operation in this embodiment is basically the same as that in Example 1. The only difference is that PEG400 in step (1) of Example 1 is replaced with polyethylene glycol 200 (PEG200), and the aqueous solution of the finally prepared aminoacylsulfonate crosslinking agent (AFS-200) is used.

[0122] Example 6

[0123] In this embodiment, the effects of aminoacylsulfonate crosslinking agents AFS-400, AFS-1, and AFS-200 prepared in Examples 1, 4, and 5 on mycelial skin crosslinking are compared.

[0124] (1) Cross-linking of AFS-1 mycelial skin prepared in Example 4

[0125] This is essentially the same as Example 2, except that the crosslinking agent was replaced with AFS-1 instead of AFS-400. A photograph of the prepared mycelial skin is shown below. Figure 7 As shown.

[0126] (2) Cross-linking of AFS-1 mycelial skin prepared in Example 4

[0127] This is essentially the same as Example 2, except that the crosslinking agent was replaced with AFS-200 instead of AFS-400. A photograph of the prepared mycelial skin is shown below. Figure 8 As shown.

[0128] The tensile strength and tear strength of the mycelial skin prepared in Example 2 and this example were tested, and the softness and fullness were evaluated. The results are shown in Table 2.

[0129] Table 2 Properties of mycelial skins prepared by cross-linking with different cross-linking agents

[0130] Crosslinking agent <![CDATA[Tensile strength (MPa / mm 2 )]]> Tear strength (N / mm) Softness fullness AFS-400 5.02 9.54 **** **** AFS-200 4.88 10.12 *** **** AFS-1 4.70 8.78 *** ****

[0131] Note: In Table 2, the degree of softness is represented by the number of asterisks (*), with more asterisks indicating better softness; the degree of fullness is represented by the number of asterisks (*), with more asterisks indicating better fullness.

[0132] As shown in Tables 1 and 2, for the crosslinking of mycelial fibers, compared with the use of commonly used small molecule crosslinking agents (such as glutaraldehyde and genipin) in existing technologies, the use of the aminoacylsulfonate crosslinking agent described in this invention can improve the mechanical and sensory properties of the mycelial skin, especially its softness and fullness. In Examples 1, 4, and 5, the chain extenders used in preparing the aminoacylsulfonate crosslinking agents AFS-400, AFS-1, and AFS-200 were PEG400, ethylene glycol, and PEG200, respectively. The different molecular chain lengths of the chain extenders resulted in different molecular chain lengths for AFS-400, AFS-1, and AFS-200. As shown in Table 2, for the crosslinking of mycelial fibers, the molecular chain length of the crosslinking agent affects the properties of the prepared mycelial skin. When the molecular chain length of the crosslinking agent is appropriate, the tensile strength and tear strength, softness and fullness of the mycelial skin can be better balanced. This addresses the problem that softness and fullness, as well as tensile strength and tear strength, are easily mutually restrictive and difficult to improve simultaneously.

[0133] Example 7

[0134] In this embodiment, an ecological cross-linking method for mycelial coat is provided, comprising the following steps:

[0135] (1) Pretreatment

[0136] Take mycelial sheets, shave them evenly, and wash them with water to remove water-soluble polysaccharides adhering to the surface of the mycelial sheets and debris generated during the shaving process, thus obtaining pretreated mycelial sheets.

[0137] (2) Crosslinking

[0138] 100 parts by weight of pretreated mycelial sheets and 100 parts by weight of water were added to a rotating drum. Then, an aqueous solution of AFS-400 prepared in Example 1 was added, controlling the concentration of AFS-400 in the bath to 10 wt% and the temperature of the bath to 40 °C. The drum was rotated intermittently at 3 rpm for 180 min (5 min per hour) to promote uniform penetration of AFS-400 into the pretreated mycelial sheets. Under the rotating drum condition, anhydrous sodium carbonate was added to adjust the pH of the bath to 7, and the temperature of the bath was adjusted to 80 °C. The drum was rotated intermittently at 3 rpm for 120 min (5 min per hour) to allow AFS-400 to undergo a cross-linking reaction with the pretreated mycelial sheets. The sheets were then removed, the water was squeezed out, and sheet-like cross-linked mycelia were obtained.

[0139] (3) Post-processing

[0140] The post-processing includes plasticizing, drying and finishing, and the operation is the same as step (3) of Example 2 to obtain mycelial skin.

[0141] The sensory evaluation of the mycelial coating prepared in this embodiment showed that it had good fullness, a soft feel, a light color, and a smooth surface. Mechanical property testing of the mycelial coating prepared in this embodiment showed that its tensile strength was 5.15 MPa / mm². 2 The tear strength is 11.98 N / mm.

[0142] Example 8

[0143] In this embodiment, an ecological cross-linking method for mycelial coat is provided, comprising the following steps:

[0144] (1) Pretreatment

[0145] Take mycelial sheets, shave them evenly, and wash them with water to remove water-soluble polysaccharides adhering to the surface of the mycelial sheets and debris generated during the shaving process, thus obtaining pretreated mycelial sheets.

[0146] (2) Crosslinking

[0147] 100 parts by weight of pretreated mycelial sheets and 200 parts by weight of water were added to a rotating drum. Then, an aqueous solution of AFS-400 prepared in Example 1 was added, controlling the concentration of AFS-400 in the bath to be 8 wt% and the temperature of the bath to be 45 °C. The drum was rotated intermittently at 3 rpm for 120 min (5 min per hour) to promote uniform penetration of AFS-400 into the pretreated mycelial sheets. Under the rotating drum condition, anhydrous sodium carbonate was added to the drum to adjust the pH of the bath to 9, and the temperature of the bath to be adjusted to 50 °C. The drum was rotated intermittently at 3 rpm for 180 min (5 min per hour) to allow AFS-400 to undergo a cross-linking reaction with the pretreated mycelial sheets. The sheets were then removed, the water was squeezed out, and sheet-like cross-linked mycelia were obtained.

[0148] (3) Post-processing

[0149] The post-processing includes plasticizing, drying and finishing, and the operation is the same as step (3) of Example 2 to obtain mycelial skin.

[0150] The sensory evaluation of the mycelial sheath prepared in this embodiment showed that it had good fullness, a soft feel, a light color, and a smooth surface. Mechanical property testing of the mycelial sheath prepared in this embodiment showed that its tensile strength was 5.11 MPa / mm². 2 The tear strength is 12.27 N / mm.

[0151] Example 9

[0152] In this embodiment, the aminoacylsulfonate crosslinking agent is prepared by the following steps:

[0153] (1) Chain extension of diisocyanates

[0154] The isophorone diisocyanate monomer and ethylene glycol were dissolved in acetone at a molar ratio of 2:1 to 2:1, so that the concentration of ethylene glycol was 30 v / v%. The reaction was carried out at 40-90 °C for 2 h. During the reaction, heat was released and the temperature was gradually increased. The temperature was controlled at 40 °C in the early stage of the reaction and at 90 °C in the later stage of the reaction to obtain the chain-extended isophorone diisocyanate solution.

[0155] (2) End capping of isocyanate group

[0156] A saturated aqueous solution of sodium bisulfite was thoroughly mixed with ethanol as a dispersant, with the amount of dispersant being 25 wt% of the saturated aqueous solution of sodium bisulfite, to obtain a capping solution. The capping solution was added to the chain-extended isophorone diisocyanate solution at a molar ratio of sodium bisulfite to isocyanate groups of 1.2:1. The mixture was stirred at 1°C for 2 h, and the organic solvent was removed under vacuum to obtain an aqueous solution of the aminoacylsulfonate crosslinking agent.

[0157] Example 10

[0158] In this embodiment, the preparation of the aminoacylsulfonate crosslinking agent is basically the same as in Example 9, except that the ethylene glycol in step (1) is replaced with polyethylene glycol 1000 (PEG1000).

[0159] Example 11

[0160] In this embodiment, the aminoacylsulfonate crosslinking agent is prepared by the following steps:

[0161] (1) Chain extension of diisocyanates

[0162] The toluene-2,4-diisocyanate monomer and PEG400 were dissolved in acetone at a molar ratio of 2.4:1 to achieve a PEG400 concentration of 35 v / v%. The reaction was carried out at 40–75 °C for 7 h, during which heat was released and the temperature was gradually increased. The temperature was controlled at 40 °C in the early stage of the reaction and at 70 °C in the later stage to obtain the chain-extended toluene-2,4-diisocyanate solution.

[0163] (2) End capping of isocyanate group

[0164] A saturated aqueous solution of sodium bisulfite was thoroughly mixed with methanol as a dispersant, with the amount of dispersant being 35 wt% of the saturated aqueous solution of sodium bisulfite, to obtain a capping solution. The capping solution was added to the chain-extended toluene-2,4-diisocyanate solution at a molar ratio of sodium bisulfite to isocyanate groups of the chain-extended toluene-2,4-diisocyanate of 1.22:1. The mixture was stirred at 4 °C for 2 h, and the organic solvent was removed under vacuum to obtain an aqueous solution of the aminoacylsulfonate crosslinking agent.

[0165] Example 12

[0166] In this embodiment, the preparation of aminoacylsulfonate crosslinking agent is basically the same as in Example 11, except that PEG400 in step (1) is replaced with polyethylene glycol 600 (PEG600).

[0167] Example 13

[0168] In this embodiment, the aminoacylsulfonate crosslinking agent is prepared by the following steps:

[0169] (1) Chain extension of diisocyanates

[0170] The diphenylmethane diisocyanate monomer and PEG400 were dissolved in acetone at a molar ratio of 2.2:1 to achieve a PEG400 concentration of 35 v / v%. The reaction was carried out at 40–75 °C for 4 h, during which heat was released and the temperature was gradually increased. The temperature was controlled at 40 °C in the early stage of the reaction and at 70 °C in the later stage to obtain the chain-extended diphenylmethane diisocyanate solution.

[0171] (2) End capping of isocyanate group

[0172] A saturated aqueous solution of sodium bisulfite was thoroughly mixed with isopropanol as a dispersant, with the amount of dispersant being 45 wt% of the saturated aqueous solution of sodium bisulfite, to obtain a capping solution. The capping solution was added to the chain-extended isophorone diisocyanate solution at a molar ratio of sodium bisulfite to isocyanate groups of the chain-extended diphenylmethane diisocyanate of 1.1:1. The mixture was stirred at 10 °C for 1 h, and the organic solvent was removed under vacuum to obtain an aqueous solution of the aminoacylsulfonate crosslinking agent.

[0173] Example 14

[0174] In this embodiment, the preparation of aminoacylsulfonate crosslinking agent is basically the same as in Example 11, except that PEG400 in step (1) is replaced with polyethylene glycol 800 (PEG800).

[0175] Example 15

[0176] In this embodiment, an ecological cross-linking method for mycelial skin is provided. The operation is basically the same as in Example 2, except that in step (2), the cross-linking agent is replaced by the cross-linking agent prepared in Example 9, and the concentration of the cross-linking agent in the bath is controlled to be 4 wt%.

[0177] Example 16

[0178] In this embodiment, an ecological cross-linking method for mycelial skin is provided. The operation is basically the same as in Example 2, except that in step (2), the cross-linking agent is replaced by the cross-linking agent prepared in Example 10, and the concentration of the cross-linking agent in the bath solution is controlled to be 6.5 wt%.

[0179] Example 17

[0180] In this embodiment, an ecological cross-linking method for mycelial skin is provided. The operation is basically the same as in Example 2, except that in step (2), the cross-linking agent is replaced by the cross-linking agent prepared in Example 11 instead of AFS-400, and the concentration of the cross-linking agent in the bath solution is controlled to be 5.5 wt%.

[0181] Example 18

[0182] In this embodiment, an ecological cross-linking method for mycelial skin is provided. The operation is basically the same as in Example 2, except that in step (2), the cross-linking agent is replaced by the cross-linking agent prepared in Example 12, and the concentration of the cross-linking agent in the bath solution is controlled to be 7.5 wt%.

[0183] Example 19

[0184] In this embodiment, an ecological cross-linking method for mycelial skin is provided. The operation is basically the same as in Example 2, except that in step (2), the cross-linking agent is replaced by the cross-linking agent prepared in Example 13, and the concentration of the cross-linking agent in the bath is controlled to be 8 wt%.

[0185] Example 20

[0186] In this embodiment, an ecological cross-linking method for mycelial skin is provided. The operation is basically the same as in Example 2, except that in step (2), the cross-linking agent is replaced by the cross-linking agent prepared in Example 14, and the concentration of the cross-linking agent in the bath is controlled to be 9 wt%.

Claims

1. An ecological cross-linking method for mycelial skin, characterized in that, Includes the following steps: (1) Pretreatment Take mycelial sheets, slice them evenly, and wash them with water to obtain pretreated mycelial sheets; the mycelial sheets are obtained by transplanting mycelia obtained from liquid fermentation onto a solid culture medium. (2) Crosslinking Add 100 parts by weight of pretreated mycelial sheets and 100-300 parts by weight of water to a rotating drum, then add a cross-linking agent to make the concentration of the cross-linking agent in the bath solution 4 wt%-12 wt%, and control the temperature of the bath solution at 35-45 ℃. Rotate the drum to allow the cross-linking agent to fully penetrate into the pretreated mycelial sheets. Under the condition of drum rotation, adjust the pH value of the bath solution to 7.0-9.0 and adjust the temperature of the bath solution to 50-80 ℃ to de-seal the end groups of the cross-linking agent and release isocyanate groups, so that the cross-linking agent with de-sealted end groups can fully chemically cross-link with the pretreated mycelial sheets. Remove the sheets, squeeze out the water, and obtain cross-linked mycelia. The general structural formula of the crosslinking agent is as follows: ， In the above formula, R is R' is or n is 2 to 23; (3) Post-processing The cross-linked mycelium obtained in step (2) was plasticized, dried and finished according to standard procedures to obtain mycelium skin.

2. The ecological cross-linking method for mycelial coat according to claim 1, characterized in that, In step (2), after adjusting the pH of the bath solution to 7.0~9.0 and the temperature of the bath solution to 50~80 ℃, the cross-linking reaction is carried out by rotating the drum for 120~180 min to obtain cross-linked mycelium.

3. The ecological cross-linking method for mycelial coat according to claim 1, characterized in that, In step (2), after adding the cross-linking agent to the drum, rotate the drum for 120~180 minutes to allow the cross-linking agent to penetrate evenly into the pretreated mycelial sheet.

4. The ecological cross-linking method for mycelial skin according to claim 1, characterized in that, Step (2) When adjusting the pH value of the bath solution, the pH value of the bath solution is adjusted by adding sodium carbonate and / or sodium hydroxide to the bath solution.

5. The ecological cross-linking method for mycelial coat according to claim 1, characterized in that, The crosslinking agent is obtained by extending the diisocyanate monomer with a diol chain extender and then capping the isocyanate groups of the extended diisocyanate with sodium bisulfite; the diisocyanate monomer is hexamethylene diisocyanate; the diol chain extender is ethylene glycol or polyethylene glycol with a molecular weight of 200-1000.

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