Biomass hypha enhanced waterborne polyurethane composite material as well as preparation method and application thereof

Abstract

The invention relates to a biomass mycelium reinforced waterborne polyurethane composite material as well as a preparation method and application thereof. Firstly, hyphae are subjected to physical and mechanical modification, chemical modification, enzyme modification and other pretreatment, then the modified hyphae are mixed with a waterborne polyurethane material, or the modified hyphae are introduced in a prepolymer reaction stage, a chain extension reaction stage and a neutralization and dispersion stage for synthesizing waterborne polyurethane, so that the modified hyphae are effectively combined with polyurethane through hydroxyl, amino and the like, and the waterborne polyurethane is prepared. The prepared waterborne polyurethane composite material has better mechanical property, wear resistance, antibacterial property and moisture permeability, can greatly improve the performance of leather products when being used as a coating agent, and meets the requirements of the leather products with higher sanitary performance requirements.

Description

Technical Field

[0001] The invention relates to the technical fields of composite materials, microorganisms and leather processing, and in particular to a biomass hypha-reinforced waterborne polyurethane composite material and a preparation method and application thereof. Background Art

[0002] Globally, the leather products industry is facing stringent environmental challenges. Traditional leather finishing agents, especially polyurethane systems based on organic solvents, provide excellent mechanical properties and durability, but are increasingly restricted due to the large amount of volatile organic compounds (VOCs) they contain. These organic compounds, when released into the atmosphere, may cause ozone layer depletion, deteriorate air quality, and ultimately pose a threat to human health. With the improvement of consumer awareness and the continued tightening of environmental regulations, the market demand for environmentally friendly leather finishing agents has increased significantly.

[0003] Waterborne polyurethane coatings have emerged as an alternative to reduce VOC emissions. Waterborne polyurethane coatings use water instead of organic solvents as a dispersion medium, reducing the impact on the environment. Although this coating alternative is more environmentally friendly, it often faces the problem of insufficient performance (such as mechanical properties, wear resistance, and antibacterial properties) in actual applications and cannot meet the needs of high-end applications.

[0004] In this context, the present invention proposes a new waterborne polyurethane finishing agent combined with biomass mycelium material, wherein the biomass mycelium material, as a renewable resource, is not only widely available and low-cost, but also has excellent mechanical reinforcement and natural antibacterial properties. By introducing this biomass material into the waterborne polyurethane system, not only the overall performance of the finishing agent is improved, but also the environmental protection standards of leather products are improved, meeting the market demand for high-performance, low-impact environmentally friendly materials. The present invention helps leather finishing agent technology move towards a more sustainable direction, and has important market prospects and environmental significance. Summary of the invention

[0005] One of the purposes of the present invention is to provide a method for preparing a biomass hyphae-reinforced waterborne polyurethane composite material, the method comprising the following steps: (a) hyphae pretreatment; (b) mixing the pretreated hyphae material with a waterborne polyurethane material, or adding the pretreated hyphae material during the synthesis of the waterborne polyurethane material, to finally obtain a hyphae-reinforced waterborne polyurethane composite material.

[0006] Furthermore, the mycelium is specifically the aerial mycelium of fungi such as Pleurotus ostreatus, Pleurotus eryngii, Lentinus edodes, Ganoderma lucidum, and Auricularia auricula.

[0007] Furthermore, the pretreatment of mycelium in step (a) includes modification treatment and post-treatment, wherein the modification treatment includes physical and mechanical modification treatment, chemical modification treatment and enzyme modification treatment.

[0008] Furthermore, the physical and mechanical modification process of the mycelium in step (a) is specifically as follows: firstly, the mycelium is mechanically broken into small pieces, and then ground into micrometer or nanometer size with water to obtain a modified mycelium liquid.

[0009] Furthermore, the mycelium liquid obtained by physical and mechanical modification treatment needs to be dispersed by ultrasonication to further reduce the size of mycelium particles and improve their dispersibility.

[0010] Furthermore, the chemical modification process of the mycelium in step (a) is specifically as follows: the pH of the unmodified mycelium solution or the physically and mechanically modified mycelium solution is adjusted to acidic (such as 2-4) or alkaline (such as 11-13), and then heated to 20-80° C. for hydrolysis (reaction 4-24 hours), thereby obtaining a chemically modified mycelium solution. The chemical modification treatment can reduce the molecular weight of the mycelium and increase its hydrophilicity.

[0011] Further, the enzymatic modification process of the mycelium in step (a) is as follows: the pH of the unmodified mycelium solution, the physically and mechanically modified mycelium solution or the chemically modified mycelium solution is adjusted to 4-8, and then the modified enzyme is added and the mixture is heated to 30-60° C. for enzymatic hydrolysis (reaction 2-4 hours) to obtain an enzyme-modified mycelium solution. The enzymatic hydrolysis treatment can continue to reduce the molecular weight of the mycelium and further improve its hydrophilicity.

[0012] Furthermore, the modified enzyme is selected from at least one of glucanase, chitinase, neutral protease, alkaline protease and trypsin, and the amount of the modified enzyme (dry weight) added during mixing is equivalent to 0.1wt%-3wt% of the mass of the mycelium (dry weight).

[0013] Furthermore, the post-treatment process of the mycelium in step (a) is specifically as follows: the modified mycelium liquid is separated into solid and liquid, and the obtained solid is repeatedly washed with water and then freeze-dried to obtain a modified mycelium material.

[0014] Furthermore, the amount of the pretreated mycelium material added in step (b) does not exceed 5 wt % of the solid content of the aqueous polyurethane.

[0015] Furthermore, the timing of adding the pretreated mycelium material in step (b) includes the prepolymer reaction stage, the chain extension reaction stage, and the neutralization and dispersion stage in the synthesis process of the waterborne polyurethane material.

[0016] Furthermore, the specific process of the prepolymer reaction stage is as follows: 80-100 mol parts of isocyanate, 10-16 mol parts of polyol, and 1-4 mol parts of polyester polyol are mixed evenly, the resulting mixture is heated to 90-110° C. to react to obtain an isocyanate prepolymer, and after cooling to 80-100° C., 0.5-1 mol parts of small molecule polyol and 0.1 mol parts of catalyst are added to continue the reaction.

[0017] Furthermore, the specific process of the chain extension reaction stage is as follows: the temperature of the mixture obtained in the prepolymer reaction stage is adjusted to 70-90° C., and then 22-30 mole fractions of a hydrophilic chain extender are added for full reaction. The introduction of carboxyl groups in the chain extension reaction stage is beneficial to improving the water dispersibility of the polyurethane.

[0018] Furthermore, the specific process of the neutralization and dispersion stage is as follows: the mixture obtained in the chain extension reaction stage is mixed with 21-30 mole parts of a neutralizing agent and stirred at a low speed, and then deionized water is added and stirred at a high speed.

[0019] Further, the isocyanate is selected from at least one of isophorone diisocyanate (IPDI), adipic acid diisocyanate (HDI), toluene diisocyanate (TDI), and diphenylmethane diisocyanate (MDI); the polyol (molecular weight 1000-3000) is selected from at least one of polypropylene glycol and polyethylene glycol; the polyester polyol (molecular weight 500-2000) is selected from at least one of adipic acid-ethylene glycol ester and sebacic acid-butylene glycol ester; the small molecule polyol is selected from at least one of diethylene glycol, ethylene glycol, and butylene glycol; and the catalyst is selected from The invention relates to a catalyst selected from at least one of a tin catalyst (such as dibutyltin dilaurate) and an organic amine catalyst (such as triethylamine, dimethylethanolamine, etc.), the hydrophilic chain extender is selected from at least one of dihydroxymethylpropionic acid (DMPA), 2,2-dihydroxymethylbutyric acid (DMBA), N-(2-hydroxyethyl)-2-aminoethanesulfonic acid (HEAS), and N-hydroxyethylaminosulfonic acid, and the neutralizer is selected from at least one of triethylamine (TEA), 2-amino-2-methyl-1-propanol (AMP), ammonia (NH3), N-methyldiethanolamine (MDEA), and ethylenediamine (EDA).

[0020] The second object of the present invention is to provide a biomass hyphae reinforced waterborne polyurethane composite material prepared according to the above method.

[0021] The third object of the present invention is to provide the use of the above-mentioned biomass hyphae reinforced waterborne polyurethane composite material as a finishing agent in leather processing.

[0022] The main purpose of physical, mechanical, chemical and biological modification of mycelium is to reduce the particle size and release more functional groups, so as to improve the dispersibility and stability of mycelium in waterborne polyurethane emulsion. The reduction of particle size allows mycelium to be more evenly distributed in the emulsion, avoiding the aggregation and sedimentation of large particles and reducing the occurrence of phase separation. The functional groups (such as hydroxyl, amino, etc.) released during the modification process can form stronger chemical bonds with the active groups in the polyurethane matrix. This enhanced interfacial interaction not only improves the mechanical properties of the composite material, but also improves its durability and stability.

[0023] Compared with the existing similar technologies, the progress of the present invention is mainly reflected in the following points: (1) The appropriate mycelium and the corresponding modification method are determined, and the mycelium size is made smaller and has more active functional groups through physical and mechanical modification, chemical modification, and enzyme modification, which can effectively combine with polyurethane to enhance its comprehensive performance; (2) The idea and specific implementation plan of using modified mycelium to enhance the comprehensive performance of waterborne polyurethane are proposed, and it is used as a leather finishing agent, which not only improves the performance of leather products, but also meets the leather processing requirements in certain special application scenarios; (3) The selected mycelium is a biomass material, which is not only widely available but also low in cost, and can greatly improve the comprehensive performance of leather finishing agents at a relatively low cost, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the modification principle of the mycelium material of the present invention.

[0025] Figure 2 This is a microscopic photograph of the mycelium after grinding, chemical modification and ultrasonic disruption in Example 2. Figure 3 This is a photo of the Ganoderma lucidum mycelium material cultured using solid surface fermentation technology used in Example 3.

[0026] Figure 4-5 This is a real photo of the Pleurotus eryngii aerial mycelium material cultivated by solid surface fermentation technology used in Example 4.

[0027] Figure 6 This is a microscopic photograph of mycelium obtained by grinding and ultrasonic disruption in Example 4.

[0028] Figure 7 This is an infrared spectrum of waterborne polyurethane with different mycelium contents prepared in Example 5.

[0029] Figure 8 This is a graph showing the high-speed centrifugation test results of the aqueous polyurethane emulsions with different mycelium contents prepared in Example 5.

[0030] Fig. 9 The following are photos of waterborne polyurethane samples with different mycelium contents prepared in Example 5.

[0031] Fig.10 This is a graph showing the elongation at break test results of waterborne polyurethane films with different mycelium contents prepared in Example 5.

[0032] Fig.11 This is a graph showing the tensile strength test results of waterborne polyurethane films with different mycelium contents prepared in Example 5.

[0033] Fig.12 This is a graph showing the wear resistance test results of waterborne polyurethane films with different mycelium contents prepared in Example 5.

[0034] Fig.13 This is a graph showing the water and air permeability test results of waterborne polyurethane membranes with different mycelium contents prepared in Example 5. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to fully understand the technical solutions and beneficial effects of the present invention, further description is given below in conjunction with specific embodiments.

[0036] It should be emphasized that the following examples are only partial implementation methods of the present invention and do not constitute a limitation of the present invention. Simple improvements made without departing from the spirit of the present invention still fall within the protection scope of the present invention.

[0037] For leather finishing, the mainstream technology on the market is to directly use chemically synthesized water-based polyurethane as leather finishing agent. The preparation process of this water-based polyurethane usually includes: firstly, chain extension reaction of polyurethane prepolymer, and then dispersing polyurethane in water to form water-based emulsion through emulsification process. The whole preparation process reduces the use of organic solvents, thereby reducing VOC emissions and improving the environmental friendliness of materials. Although this type of water-based polyurethane finishing agent has some advantages in environmental protection, it still has defects in the following key aspects:

[0038] (1) Poor mechanical properties and wear resistance: Compared with traditional organic solvent-based polyurethane, water-based polyurethane generally performs poorly in hardness and wear resistance, which limits its application in high-end leather products with high durability requirements.

[0039] (2) Weak antibacterial properties: Existing waterborne polyurethanes lack effective antibacterial properties, resulting in them not meeting usage standards in some specific applications (such as leather products in the medical and hygiene fields).

[0040] In order to solve these problems, we developed a biomass mycelium reinforced waterborne polyurethane composite material and used it as a leather finishing agent in leather finishing treatment, achieving good results.

[0041] The main components of the mycelial cell wall include polysaccharides, chitin and proteins, each of which plays an important role in the cell wall. Polysaccharides account for 50% to 60% of the total weight of the cell wall and are the main skeleton of the cell wall, providing the mechanical strength and toughness of the cell wall. Chitin accounts for 10% to 20% of the total weight of the cell wall, and its main component is N-acetyl-D-glucosamine (N-acetyl-D-glucosamine) polymer. Chitin gives the cell wall high strength and rigidity, enhancing the hardness and stability of the cell wall. Proteins account for 20% to 30% of the total weight of the cell wall, mainly including various structural proteins and functional proteins, such as hydrolases and transporters.

[0042] The principle of mycelium modification of the present invention is as follows Figure 1 As shown, the hydrolysis reaction of polysaccharides is mainly catalyzed by mechanical grinding, acid, alkali, and enzyme to release hydroxyl (-OH), decompose protein to release amino (-NH2) and carboxyl (-COOH), and deacetylate chitin to release amino (-NH2). These hydroxyl, amino, carboxyl, etc. provide more active sites for the synthesis of polyurethane. The present invention can introduce modified mycelium at various stages of synthesizing waterborne polyurethane, thereby utilizing the abundant hydroxyl, amino, etc. on the modified mycelium material to react with the isocyanate in the polyurethane to ensure the effective combination of mycelium and polyurethane chain, thereby enhancing the mechanical properties of the composite material. The introduction of modified mycelium material not only improves the mechanical properties and wear resistance of waterborne polyurethane, but also enhances the antibacterial properties and water-permeable properties, making the coated leather products more suitable for applications with high requirements for hygienic properties.

[0043] Example 1

[0044] (1) Mycelium modification treatment.

[0045] Mechanical crushing modification: The biomass raw material is pure aerial mycelium of Pleurotus ostreatus obtained by solid surface fermentation technology. According to the volume ratio of 1:10, the harvested pure mycelium is added to deionized water, and the mycelium in the solution is mechanically crushed to micron level by a high-speed crusher to obtain mycelium liquid.

[0046] Ultrasonic dispersion: The mycelial liquid after mechanical disruption was transferred to an ultrasonic processor and ultrasonically treated at a power of 300 W for 30 min.

[0047] Chemical modification: hydrochloric acid was added to the mycelial solution after ultrasonic treatment to adjust the pH of the solution to 2, followed by hydrolysis at 20°C for 4 h.

[0048] Enzymatic modification: sodium hydroxide solution (10 wt%) was added dropwise to the chemically modified mycelium solution, the pH of the mixture was adjusted to 5, and then 0.1 wt % chitinase was added. The mixture was then heated to 40° C. and enzymatically hydrolyzed for 4 h to obtain the modified mycelium solution.

[0049] Post-treatment: The modified mycelium liquid was centrifuged and the obtained solid was repeatedly washed with deionized water and then freeze-dried to obtain the nano-scale mycelium material JSN-G.

[0050] (2) Polymerization of modified mycelium material and polyurethane.

[0051] Step 1: Preparation of isocyanate prepolymer (Operation A)

[0052] 100 mol of isophorone diisocyanate (IPDI), 14 mol of polypropylene glycol with a molecular weight of 1000, and 1 mol of adipic acid-ethylene glycol ester with a molecular weight of 500 were mixed evenly, and then heated to 90°C for 3 hours to obtain an isocyanate prepolymer. The mixture was cooled to 80°C, and 0.5 mol of diethylene glycol, 0.1 mol of catalyst dibutyltin dilaurate and 0.1 wt% of JSN-G were added, and the mixture was kept warm for 2 hours at this temperature.

[0053] Step 2: Chain extension reaction (operation B)

[0054] The mixture after the previous step of reaction was cooled to 70° C., and 23 mol of a hydrophilic chain extender, dimethylol propionic acid (DMPA), was added to continue the reaction for 2 hours.

[0055] Step 3: Neutralization and Dispersion (Operation C)

[0056] 22 mol of neutralizing agent triethylamine TEA was added to the mixture after the chain extension reaction was completed, and deionized water 3 times the total mass of the mixture was added after low-speed stirring for 5 minutes, and high-speed stirring was performed for 120 seconds to obtain mycelium-modified waterborne polyurethane finishing agent H-1.

[0057] Example 2

[0058] (1) Mycelium modification treatment.

[0059] Mechanical crushing modification: Solid surface fermentation technology is used to prepare pure aerial mycelium of Lentinus edodes. The harvested mycelium is added to deionized water at a volume ratio of 1:10, and the mycelium in the solution is mechanically crushed to nanometer level using a high-speed crusher to obtain mycelium liquid.

[0060] Chemical modification: sodium hydroxide was added to the mycelium solution to adjust the pH of the solution to 13, and then heated to 80°C for hydrolysis for 4 hours.

[0061] Ultrasonic dispersion: The chemically modified mycelial liquid was neutralized to pH = 7, and then transferred to an ultrasonic processor and ultrasonically treated at a power of 600 W for 30 min.

[0062] Post-treatment: The modified mycelium liquid was centrifuged and the obtained solid was repeatedly washed with deionized water and freeze-dried to obtain the nano-scale modified mycelium material JSN-G, the micrograph of which is shown in Figure 2 shown.

[0063] (2) Polymerization of modified mycelium material and polyurethane.

[0064] Step 1: Preparation of isocyanate prepolymer (Operation A)

[0065] 80 mol of mixed isocyanate (molar ratio of isophorone diisocyanate IPDI to adipic acid diisocyanate HDI = 1:1), 10 mol of polyethylene glycol with a molecular weight of 3000, and 4 mol of sebacic acid-butylene glycol ester with a molecular weight of 2000 were mixed evenly, and then heated to 110°C for 3 hours. After the reaction, the temperature was lowered to 100°C, and 1 mol of butanediol and 0.1 mol of catalyst triethylamine were added to continue the reaction for 2 hours to obtain an isocyanate prepolymer.

[0066] Step 2: Chain extension reaction (operation B)

[0067] The mixture obtained in the previous step was cooled to 90° C., and 30 mol of hydrophilic chain extender DMPA and 1.5 wt % of JSN-G were added to continue the reaction for 3 h.

[0068] Step 3: Neutralization and Dispersion (Operation C)

[0069] 29 mol of ammonia water (NH3) was added to the mixture after the chain extension reaction was completed, and after stirring at a low speed for 10 minutes, deionized water 4 times the total mass of the mixture was added, and stirred at a high speed for 300 seconds to obtain mycelium-modified waterborne polyurethane coating agent H-2.

[0070] Example 3

[0071] (1) Mycelium modification treatment.

[0072] Mechanical crushing modification: Biomass raw materials are such as Figure 3 The pure aerial mycelium of Ganoderma lucidum obtained by solid surface fermentation technology is shown. The harvested pure mycelium is added to deionized water at a volume ratio of 1:10, and the mycelium in the solution is mechanically crushed to micron level by a high-speed crusher to obtain mycelium liquid.

[0073] Enzymatic modification: 3 wt % of glucanase was added to the mycelial solution obtained in the previous step, and then hydrochloric acid was added to adjust the pH of the solution to 5, and then the mixture was heated to 50° C. and kept for enzymatic hydrolysis for 2 h to obtain the modified mycelial solution.

[0074] Ultrasonic dispersion: The mycelial liquid obtained by chemical modification was transferred to an ultrasonic processor and ultrasonically treated at a power of 900 W for 10 min.

[0075] Post-treatment: The modified mycelium liquid obtained in the previous step was centrifuged, and the obtained solid was repeatedly washed with deionized water and then freeze-dried to obtain the nano-scale modified mycelium material JSN-G.

[0076] (2) Polymerization of modified mycelium material and polyurethane.

[0077] Step 1: Preparation of isocyanate prepolymer (Operation A)

[0078] 90 mol of toluene diisocyanate (TDI), 13 mol of polypropylene glycol with a molecular weight of 2000, and 3 mol of polyethylene glycol with a molecular weight of 1500 were mixed evenly, and then heated to 100°C for 2.5 hours to obtain an isocyanate prepolymer. After the reaction was completed, the temperature was lowered to 90°C, and then 0.8 mol of butanediol and 0.1 mol of catalyst dimethylethanolamine were added to continue the reaction for 3 hours.

[0079] Step 2: Chain extension reaction (operation B)

[0080] The mixture after the previous step of reaction was cooled to 80° C., and 26 mol of hydrophilic chain extender dimethylol propionic acid DMPA was added to continue the reaction for 2.5 hours.

[0081] Step 3: Neutralization and Dispersion (Operation C)

[0082] 26 mol of neutralizing agent ethylenediamine EDA was added to the mixture after the chain extension reaction was completed and stirred at low speed for 8 minutes. 5 wt% of JSN-G was dispersed in deionized water 3 times the total mass of the mixture, and then the dispersion was added to the mixture and stirred at high speed for 120 seconds to obtain mycelium modified waterborne polyurethane finishing agent I-1.

[0083] Example 4

[0084] (1) Mycelium modification treatment.

[0085] Mechanical crushing modification: Biomass materials are such as Figure 4-Figure 5 The pure aerial mycelium of Pleurotus eryngii obtained by solid surface fermentation technology is shown. The harvested pure mycelium is added to deionized water at a volume ratio of 1:40, and the mycelium in the solution is fully mechanically crushed to micron level by a grinder to obtain mycelium liquid.

[0086] Ultrasonic dispersion: The mycelium liquid obtained in the previous step was transferred to an ultrasonic processor and ultrasonically treated at a power of 900 W for 40 min to obtain physically modified micron-sized mycelium liquid JSN. The micrograph thereof is shown in FIG. Figure 6 shown.

[0087] (2) Polymerization of modified mycelium material and polyurethane.

[0088] Step 1: Preparation of isocyanate prepolymer (Operation A)

[0089] 90 mol of toluene diisocyanate (TDI), 13 mol of polypropylene glycol with a molecular weight of 2000, and 3 mol of polyethylene glycol with a molecular weight of 1500 were mixed evenly, and then heated to 100°C for 2.5 hours to obtain an isocyanate prepolymer. After the reaction was completed, the temperature was lowered to 90°C, and then 0.8 mol of diethylene glycol and 0.1 mol of catalyst dimethylethanolamine were added to continue the reaction for 3 hours.

[0090] Step 2: Chain extension reaction (operation B)

[0091] The mixture after the previous step of reaction was cooled to 80° C., and 26 mol of hydrophilic chain extender dimethylol propionic acid DMPA was added to continue the reaction for 2.5 hours.

[0092] Step 3: Neutralization and Dispersion (Operation C)

[0093] 26 mol of neutralizing agent triethylamine TEA was added to the mixture after the chain extension reaction was completed and stirred at low speed for 6 minutes. 0.9 wt% of JSN was dispersed in deionized water 3 times the total mass of the mixture, and then the dispersion was added to the mixture and stirred at high speed for 300 seconds to obtain mycelium modified waterborne polyurethane finishing agent I-2.

[0094] Example 5

[0095] (1) Mycelium modification treatment.

[0096] Mechanical crushing modification: Solid surface fermentation technology is used to prepare pure aerial mycelium of Auricularia auricula. The harvested pure mycelium is added to deionized water at a volume ratio of 1:10, and the mycelium in the solution is mechanically crushed to micron level using a high-speed crusher to obtain mycelium liquid.

[0097] Chemical modification: hydrochloric acid was added to the mycelial solution to adjust the pH of the solution to 2, followed by hydrolysis at 20°C for 4 h.

[0098] Enzymatic modification: sodium hydroxide solution (10 wt%) was added to the chemically modified mycelium solution, the pH of the mixture was adjusted to 6, 0.1 wt % chitinase was added, and then the mixture was heated to 55° C. for enzymolysis for 4 h.

[0099] Ultrasonic dispersion: The enzymatically modified mycelial liquid was transferred to an ultrasonic processor and ultrasonically treated at a power of 300 W for 30 min.

[0100] Post-treatment: The mycelium liquid was centrifuged and the obtained solid was repeatedly washed with deionized water and then freeze-dried to obtain the nano-scale mycelium material JSN-G.

[0101] (2) Composite of modified mycelium material and polyurethane.

[0102] The prepared JSN-G is directly added to the polyurethane leather finishing material and mixed evenly before use, wherein the amount of JSN-G added is equivalent to 2wt% of the solid content of the polyurethane.

[0103] In order to fully understand the performance of the biomass mycelium reinforced leather finishing agent prepared by the present invention, referring to the method in Example 4, water-based polyurethane finishing agents M-PU0, M-PU1, M-PU2, M-PU3, M-PU4, and M-PU5 with different mycelium contents were prepared when the mycelium dosage was 0wt%, 0.1wt%, 0.3wt%, 0.5wt%, 0.7wt%, and 0.9wt%.

[0104] A certain amount of water-based polyurethane finishing agent with different mycelium contents was added dropwise to the polytetrafluoroethylene template, and the template was dried at room temperature for 48 hours, then transferred to a 60°C oven for drying for 72 hours, and finally the formed film was peeled off and placed in a dryer for later use. The infrared, emulsion stability, mechanical properties, wear resistance, water absorption and water permeability of each film sample were tested and evaluated with reference to the corresponding standards. The detailed test results are as follows: Figure 7-Figure 13 shown.

[0105] (1) FTIR test

[0106] The Fourier transform infrared spectroscopy (FTIR) test was carried out on a Tensor 27 Fourier transform infrared-Raman spectrometer from Bruker, Germany, using the KBr pellet method. The spectrum scanning range was 600-4000 cm -1 , the test results are as follows Figure 7 shown.

[0107] Infrared spectroscopy results show that the introduction of mycelium has a significant effect on the chemical structure of waterborne polyurethane film, especially in -OH (3400cm -1 about) and C=O(1645cm -1 The wider hydrogen bonding absorption peak in the M-PU5 film indicates that additional interactions may be formed between the mycelium and the polyurethane matrix through hydrogen bonding. The slight shift of the C=O group absorption peak (1629cm -1 To 1627cm -1 ), further supporting the possibility of chemical interaction between the two. In summary, the addition of hyphae not only changed the chemical structure of the membrane, but also affected other properties.

[0108] (2) Analysis of stability of waterborne polyurethane emulsion

[0109] The prepared waterborne polyurethane finishing agents with different mycelium contents were added into a centrifuge and rotated at 10,000 rpm for 10 and 20 min respectively to observe whether the emulsion had precipitation. The results were as follows: Figure 8 As shown in the figure, the samples from left to right in ac are M-PU0, M-PU1, M-PU2, M-PU3, M-PU4, and M-PU5.

[0110] (3) Air conditioning

[0111] The prepared series of waterborne polyurethane films were placed in air conditioning at (20±2)°C and relative humidity (65±2)% for 48 hours, and then the tensile strength, elongation at break, abrasion resistance, water absorption and water vapor permeability of each film were measured according to the following methods.

[0112] (4) Mechanical properties test

[0113] According to the GB / T 1040.1-2018 test standard, the air-conditioned waterborne polyurethane film is made into a dumbbell shape (such as Fig. 9 As shown in the figure, the samples from left to right are M-PU0, M-PU1, M-PU2, M-PU3, M-PU4, M-PU5), and then their tensile strength and elongation at break were tested on a universal tensile machine (tensile speed 100mm / min). Each sample was tested 3 times and the average value was taken. The results are shown in Figure 10-11 shown.

[0114] In terms of mechanical properties, the introduction of appropriate amount of mycelium material (comparison between 0wt% and 0.3wt%) increased the elongation at break of the waterborne polyurethane film by about 24.8% (from 292.2% to 364.7%) and the tensile strength by 17.2% (from 7.25N / mm 2 Increased to 8.5N / mm 2 ), indicating that the modified mycelium effectively enhanced the flexibility and tensile strength of the waterborne polyurethane film.

[0115] (5) Wear resistance test

[0116] According to the GB / T 1768-2006 test standard, the wear test uses a Taber instrument, a rubber grinding wheel, a load of 500g, and a rotation of 500 revolutions. The mass of the sample before and after the rotation is measured. The wear is calculated according to formula (1). The lower the wear, the better the wear resistance of the material.

[0117] Wear (mg) = M1-M2 Formula (1)

[0118] Among them, M1 is the sample mass before the test, and M2 is the sample mass after the test.

[0119] Wear resistance test results are as follows Fig.12 In terms of wear resistance, the addition of mycelium material significantly reduced the wear loss of polyurethane material from 3.37 mg to 2.47 mg, a decrease of 26.7%, showing a significant improvement in wear resistance.

[0120] (6) Water and air permeability test

[0121] Measure 30mL of water and place it in the test dish. Place the rubber gasket and the membrane sample in turn. Tighten the aluminum screw cap to ensure that there is no air leakage and then weigh it on a balance. Place the test dish in a desiccator filled with desiccant (silica gel particles), and then place the desiccator in air at (20±1)℃ for 24 hours. After standing still, weigh it and calculate its water permeability according to formula (3).

[0122] Water permeability (mg / cm 2 ·24h)=G1-G2 Formula (3)

[0123] Wherein, G1 is the total mass of the film sample and the test dish before being placed in the desiccator, mg; G2 is the total mass of the film sample and the test dish after being placed in the desiccator and left to stand for 24 hours, mg.

[0124] The water permeability test results are as follows: Fig.13 As shown in the figure, it can be seen that the modified mycelium also has a significant effect on the water vapor permeability of the waterborne polyurethane membrane. With the increase of the amount of mycelium material, the water vapor permeability of the waterborne polyurethane membrane is significantly improved, especially at 0.3wt%, the water vapor permeability increases from 6.9g / cm 2 ·24h increased to 11.6g / cm 2 ·24h, the increase reached 68.1%. When the amount of mycelium material increased to 0.9wt%, the water permeability further increased to 14.1g / cm 2 ·24h, the increase reached 104.3%. This shows that the modified mycelium not only improves the mechanical and wear resistance of the waterborne polyurethane membrane, but also significantly enhances its water permeability, making it comprehensively optimized and improved in various performances.

[0125] from Figure 7-Figure 13 It can be seen that the introduction of mycelium has significantly enhanced the mechanical properties, wear resistance and water vapor permeability of waterborne polyurethane membranes.

Claims

1. A method for preparing a waterborne polyurethane composite material reinforced with biomass hyphae, characterized in that The method comprises the following steps: (a) pre-treating mycelium; and (b) mixing the pre-treated mycelium material with a waterborne polyurethane material, or adding the pre-treated mycelium material during the synthesis of the waterborne polyurethane material, to finally obtain a mycelium-reinforced waterborne polyurethane composite material.

2. The method according to claim 1, characterized in that: The hyphae are specifically aerial hyphae of fungi such as Pleurotus ostreatus, Pleurotus eryngii, Lentinus edodes, Ganoderma lucidum or Auricularia auricula.

3. The method according to claim 1, characterized in that: The pretreatment of mycelium in step (a) includes modification treatment and post-treatment, wherein the modification treatment includes physical and mechanical modification treatment, chemical modification treatment and enzyme modification treatment.

4. The method according to claim 3, characterized in that: The physical and mechanical modification process of the mycelium in step (a) is specifically as follows: firstly, the mycelium is mechanically broken into small pieces, and then water is added to grind them to micrometer or nanometer scale to obtain mycelium liquid.

5. The method according to claim 3, characterized in that: The chemical modification process of mycelium in step (a) is specifically as follows: the pH of the unmodified mycelium liquid or the modified mycelium liquid is adjusted to acidic or alkaline, and then heated to 20-80° C. for hydrolysis, thereby obtaining the chemically modified mycelium liquid.

6. The method according to claim 3, characterized in that: The enzyme modification treatment process of the mycelium in step (a) is specifically as follows: the pH of the unmodified mycelium liquid or the modified mycelium liquid is adjusted to 4-8, and after adding the modifying enzyme, the mixture is heated to 30-60°C for enzymolysis to obtain an enzyme-modified mycelium liquid; the modifying enzyme is selected from at least one of glucanase, chitinase, neutral protease, alkaline protease, and trypsin, and the amount of the modified enzyme added during mixing is equivalent to 0.1wt%-3wt% of the mass of the mycelium.

7. The method according to claim 3, characterized in that: The mycelium post-treatment process in step (a) is specifically as follows: the modified mycelium liquid is separated into solid-liquid and the obtained solid is repeatedly washed with water and then freeze-dried to obtain a modified mycelium material.

8. The method according to claim 1, characterized in that: The amount of the pretreated mycelium material added in step (b) does not exceed 5wt% of the solid content of the waterborne polyurethane, and the timing of adding the pretreated mycelium material includes the prepolymer reaction stage, chain extension reaction stage, and neutralization and dispersion stage of synthesizing the waterborne polyurethane material.

9. A waterborne polyurethane composite material reinforced with biomass hyphae, characterized in that: The composite material is prepared according to any one of the methods of claims 1-8.

10. Use of the biomass hyphae reinforced waterborne polyurethane composite material according to claim 9 as a finishing agent in leather processing.

Images