A method for producing bio-based leather using fungal fruiting bodies in combination with in situ reactions

Abstract

The application discloses a kind of preparation biological base leather by fungi fruit body combined in-situ reaction, belong to biological base material technical field.The preparation of biological base leather of the application includes: fungi fruit body is carried out in-situ reaction under the action of propylene lactone and catalyst, forms surface modified fungi fruit body, drying, pulverization, and obtains modified fungi fruit body micro powder;Then again with with polyurethane synthetic monomer solution, modified cellulose is mixed, and stirred reaction;After the solution of reaction is drawn, solvent is removed, and dried, and leather base is prepared;Leather base is according to the processing method of conventional microfiber leather, and is polished, veneered, embossed, and prepared biological base leather finished product.The preparation process of the method is small to environmental pollution, and the finished product leather prepared has excellent mechanical properties, and also has good biodegradability, and the product has application value in fashion field, luggage, household, clothing decoration and the like.

Description

Technical Field

[0001] This invention relates to a method for preparing bio-based leather using fungal fruiting bodies combined with in-situ reactions, belonging to the field of bio-based materials technology. Background Technology

[0002] Animal leather products have long been considered high-end items, used in footwear, apparel, home furnishings, automobiles, aircraft, and many other fields. However, the supply of raw animal hides is limited, and the production process is highly polluting, generating significant amounts of waste and pollutants, placing immense pressure on the environment. As environmental awareness intensifies, the development of animal leather products is further constrained.

[0003] In recent years, microfiber synthetic leather has become the best alternative to animal leather due to its superior performance. However, microfiber synthetic leather uses microfibers with fewer hydrophilic groups, resulting in poor moisture absorption and transfer capabilities, leading to a significant gap in moisture-wicking performance compared to animal leather. Therefore, finding new raw materials with superior performance for the development of leather products is of great significance.

[0004] Chinese patent CN109736097A discloses the introduction of hydrophilic bacterial cellulose into traditional microfibers, thereby improving the breathability and moisture permeability of leather. CN115418866A and CN113638237A disclose methods for preparing novel leather materials using plant bast fibers, such as pineapple leaf fiber, coconut shell fiber, and hemp fiber. CN111455681A discloses a method for preparing novel leather materials using agricultural and forestry waste, such as crop straw and wood, through steaming and pulping. In addition, leathers based on natural materials or waste, such as apple, pineapple, cactus, and mycelium leathers (CN114438795A, CN115135747A, CN116446188A), are receiving increasing attention.

[0005] Fruiting bodies are composed of organized mycelium, a renewable natural resource with good hydrophilicity. The raw materials are widely available and inexpensive, and the production process does not produce environmental pollution and consumes carbon dioxide. Mushrooms and fungi consumed in daily life fall into the category of fruiting bodies. However, due to their poor mechanical properties and leather-like texture, fruiting bodies usually cannot be used alone to produce leather products. They need to be compounded with appropriate polyurethane. When compounded with polyurethane, the high viscosity of the polyurethane polymer makes uniform penetration and dispersion in fiber materials and natural waste materials difficult. Furthermore, the significant difference in hydrophilicity and hydrophobicity between polyurethane polymers and these natural materials results in poor interfacial interactions, leading to low filler content of these natural biomass materials in leather products and poor performance of the finished leather products. Summary of the Invention

[0006] To address the shortcomings and deficiencies of existing technologies, this invention provides a method for preparing bio-based leather using fungal fruiting bodies combined with in-situ reactions. Specifically, by modifying and pulverizing the fruiting bodies, and combining this with in-situ synthesis of polyurethane polymers, the uniformity of the fruiting bodies' dispersion in the final leather base is effectively improved. This avoids the problems of poor dispersion and easy agglomeration of fruiting bodies in high-viscosity polyurethane solutions, thereby increasing the filling amount of fruiting bodies in the leather and the overall performance of the leather.

[0007] The first objective of this invention is to provide a method for preparing bio-based leather using fungal fruiting bodies combined with in-situ reactions, the method comprising the following steps:

[0008] (1) The fungal fruiting bodies are reacted in situ under the action of lactide and catalyst to form surface-modified fungal fruiting bodies, which are then dried to a moisture content of 0.001-0.01%, pulverized and sieved to obtain fine powder of modified fungal fruiting bodies.

[0009] (2) The modified fungal fruiting body fine powder obtained in step (1) is mixed with polyurethane synthetic monomer solution and modified cellulose, and stirred to react; the solution after reaction is cast, solvent removed, and dried to obtain leather base;

[0010] (3) The leather base prepared in step (2) is polished, laminated and embossed according to the conventional microfiber leather processing method to obtain the bio-based leather finished product.

[0011] In one embodiment, the fungal fruiting body in step (1) includes one or more of the following: enoki mushroom, tea tree mushroom, king oyster mushroom, white jade mushroom, lion's mane mushroom, morel mushroom, or northern wind mushroom.

[0012] In one embodiment, the catalyst in step (1) is one or more of stannous octoate, stannous chloride, and p-toluenesulfonic acid.

[0013] In one embodiment, the amount of catalyst used in step (1) is 1‰ to 5‰ of the mass of lactide.

[0014] In one embodiment, the mass ratio of propiolactone to fungal fruiting body in step (1) is 5 to 8:2.

[0015] In one embodiment, the in-situ reaction in step (1) specifically refers to mixing fungal fruiting bodies with lactide and a catalyst, and carrying out an in-situ reaction at 100-120°C; through the in-situ ring-opening polymerization of lactide on the surface of fungal fruiting bodies, the surface grafting modification of fungal fruiting bodies by polylactic acid molecular chain segments is achieved.

[0016] In one embodiment, the drying temperature in step (1) is 60-150°C.

[0017] In one embodiment, the pulverization in step (1) is carried out using a high-speed pulverizer with a rotation speed of 20,000 to 25,000 r / min.

[0018] In one embodiment, the sieve used in step (1) has a mesh size of 200 to 300.

[0019] In one embodiment, the polyurethane synthetic monomer solution in step (1) is formed by mixing and reacting oligomeric diols, chain extenders and isocyanates with DMF as solvent.

[0020] In one embodiment, the sum of the oligomeric diol, chain extender, and isocyanate is added at 10-50% (w / w) of the dry weight of the fungal fruiting body fine powder, wherein the molar ratio of oligomeric diol plus chain extender to isocyanate is 1:1-1.5.

[0021] In one embodiment, the oligomeric diol is one or more of the diols copolymerized from oligolactic acid diol, polycaprolactone diol, or lactide-caprolactone, with a weight-average molecular weight of 400-3000 g / mol.

[0022] In one embodiment, the chain extender is one or more of 1,4-butanediol, 1,6-hexanediol, and 1,10-decanediol.

[0023] In one embodiment, the isocyanate is one or more of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), and dicyclohexylmethane diisocyanate (HMDI); preferably hexamethylene diisocyanate.

[0024] In one embodiment, the modified cellulose in step (2) refers to the hydrophobic modification of cellulose, including one or more of modified viscose fiber, modified Tencel fiber, modified bacterial cellulose, modified cotton linter, modified bamboo fiber, and modified hemp fiber.

[0025] In one embodiment, the modified cellulose fiber in step (2) has a length of 5-10 mm and is added at 10-50% (w / w) of the dry weight of the fungal fruiting body fine powder.

[0026] In one embodiment, the preparation of the modified viscose short fibers in step (2) includes the following:

[0027] Unmodified viscose staple fibers are dried in an oven to remove moisture, then added to molten lactide, followed by stannous octoate catalyst, and reacted at 100-120℃ for 2-5 hours. The viscose staple fibers are then removed, and the ungrafted polylactic acid components on the surface of the viscose staple fibers are removed with dichloromethane to obtain modified viscose fibers with polylactic acid segments grafted onto the surface.

[0028] In one embodiment, the solvent removal in step (2) includes solvent removal by water extraction or solvent removal by high-temperature drying, wherein the temperature for solvent removal by high-temperature drying is 120-160°C and the time is 3-5 min.

[0029] In one embodiment, the stirring reaction temperature in step (2) is 80-120°C and the reaction time is 2-5 hours.

[0030] In one embodiment, the drying temperature in step (2) is hot air drying at 80-120°C.

[0031] A second objective of this invention is to provide a bio-based leather prepared by the method described above.

[0032] A third objective of this invention is to provide an application of the aforementioned bio-based leather in the fields of bags, footwear, and decoration.

[0033] The beneficial effects of this invention are:

[0034] (1) By modifying and pulverizing the fruiting body and combining it with in-situ synthesis of polyurethane polymer, this invention effectively improves the dispersion uniformity of the fruiting body in the final leather base, avoids the problem of the fruiting body being difficult to disperse and easy to agglomerate in high viscosity polyurethane solution, and increases the filling amount of the fruiting body in the leather.

[0035] (2) This invention improves the interfacial interaction between the modified fruiting body powder and polyurethane by reacting the modified fruiting body powder with a polyurethane synthetic monomer solution formed by oligomeric diol, chain extender and isocyanate, thus ensuring the comprehensive performance of the final fruiting body leather products.

[0036] (3) The method of the present invention produces bio-based leather products with a fungal fruiting body filling content of 60-80%, a bio-based content of 70-90%, and a water vapor permeability of 1-3 mg / cm³. 2 It has a bending resistance of 15,000-30,000 cycles, an abrasion resistance of 1,000-2,000 cycles, a breaking strength of 30-60 MPa, and an elongation at break of 50-200%, exhibiting excellent overall performance. Detailed Implementation

[0037] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0038] The testing method involved in this invention:

[0039] Water vapor permeability test: The test method for water vapor permeability of leather in GB / T 1811-1993 was adopted.

[0040] Bending resistance test: The test was conducted according to the method described in GB / T 4689.9-1984.

[0041] Abrasion resistance test: At 23±2℃, the surface of the abrasion machine is observed after rotating a certain number of revolutions under a load of 1kg.

[0042] Mechanical property testing: The sample was cut into thin strips of 1×10cm and subjected to tensile testing on a universal testing machine at a tensile speed of 5cm / min.

[0043] Preparation of modified viscose short fibers involved in the embodiments of the present invention:

[0044] First, 20g of unmodified viscose staple fiber was dried in an oven at 105℃ for 2 hours to remove moisture. Then, it was added to 20g of molten lactide, and 5‰ of stannous octoate was added as a catalyst. The mixture was reacted at 120℃ for 5 hours. The viscose staple fiber was then removed, and the ungrafted polylactic acid components on the surface of the viscose staple fiber were removed with dichloromethane to obtain modified viscose fiber with polylactic acid segments grafted onto its surface.

[0045] Unmodified viscose staple fiber: purchased from Xinxiang Chemical Fiber Co., Ltd., filament with specifications of 120D / 30F, and cut to the required length by myself.

[0046] Example 1

[0047] A method for preparing bio-based leather using fungal fruiting bodies combined with in-situ reactions, the method comprising the following steps:

[0048] (1) 20g of dried king oyster mushroom was added to 50g of lactide, and then 5‰ of the mass of lactide stannous octoate catalyst was added. The reaction was carried out in situ at 120℃ for 5h. After the reaction was completed, the ungrafted polylactic acid was removed by washing with dichloromethane to obtain modified king oyster mushroom with surface grafted polylactic acid molecular chain segments. Then, it was vacuum dried at 120℃ until the moisture content was 0.005%. Then, it was pulverized in a pulverizer with a speed of 20000r / min and large particles were removed by a 300-mesh sieve to obtain modified king oyster mushroom fine powder.

[0049] (2) Using DMF as a solvent, oligolactic acid glycol, 1,4-butanediol, and hexamethylene diisocyanate with a weight average molecular weight of 1000 g / mol were mixed in a molar ratio of 0.5:0.5:1.2 to form a polyurethane synthetic monomer; then, the polyurethane synthetic monomer was compounded with modified king oyster mushroom powder at 20% of the mass of the modified king oyster mushroom powder, and then modified viscose short fibers with a length of 10 mm at 20% (w / w) of the mass of the modified king oyster mushroom powder were added and stirred evenly to finally prepare a DMF solution with a ratio of king oyster mushroom powder / polyurethane monomer / modified viscose fiber of 30% (w / w); the reaction was stirred at 90℃ for 3 h to obtain a king oyster mushroom powder / polyurethane / modified viscose fiber solution, the solution was cast, spread, and immersed in water to extract DMF, while polyurethane film was formed. After drying at 100℃, a leather base of king oyster mushroom powder / polyurethane / modified viscose fiber was obtained.

[0050] (3) The leather base prepared in step (2) is polished, laminated and embossed according to the conventional microfiber leather processing method to obtain the bio-based leather product based on king oyster mushroom powder.

[0051] The leather product prepared in this embodiment has a fungal fruiting body filling content of 71.5%, a bio-based component content of 86%, and a measured water vapor permeability of 2.5 mg / cm³. 2 It has a bending resistance of 23,000 cycles, an abrasion resistance of 1,200 cycles, a breaking strength of 38 MPa, and an elongation at break of 150%.

[0052] Example 2

[0053] The only difference from Example 1 is that the method of "immersing in water to extract DMF" in step (2) is replaced with a high-temperature treatment of 150°C for 3 minutes. All other conditions and parameters are the same as in Example 1, and bio-based leather products are made.

[0054] In this embodiment, the high-temperature removal of DMF does not affect the fungal fruiting body filling amount and bio-based component content of the final leather product, which are 71.5% and 86% respectively. The water vapor permeability is 2.2 mg / cm2.h, the flexural strength is 26,000 cycles, the abrasion resistance is 1,500 cycles, the tensile strength is 50 MPa, and the elongation at break is 60%. The high-temperature removal of DMF makes the final leather product more dense and reduces the breathability, but increases the flexural strength, abrasion resistance, and mechanical properties.

[0055] Example 3

[0056] The only difference from Example 1 is that the amount of polyurethane synthetic monomer added in step (2) is changed to 50% of the mass of king oyster mushroom powder. All other parameters and conditions are the same as in Example 1, and bio-based leather products are made.

[0057] The leather product prepared in this embodiment has a fungal fruiting body filling content of 60%, a bio-based component content of 82%, and a measured water vapor permeability of 2.0 mg / cm³. 2 It has a bending resistance of 25,000 cycles, an abrasion resistance of 1,500 cycles, a breaking strength of 42 MPa, and an elongation at break of 120%.

[0058] Comparative Example 1

[0059] The only difference from Example 1 is that step (1) of surface grafting modification of king oyster mushroom is omitted, and step (2) the modified king oyster mushroom is directly replaced with king oyster mushroom powder. Other parameters and conditions are the same as in Example 1, and bio-based leather products are made.

[0060] The amount of *Pleurotus ostreatus* fruiting bodies and the content of bio-based components in the bio-based leather products prepared in this comparative example are basically the same as those in Example 1, at 71.5% and 86%, respectively. The water vapor permeability was measured to be 2.6 mg / cm³. 2 The bending resistance is 12,000 cycles, the abrasion resistance is 800 cycles, the breaking strength is 15 MPa, and the elongation at break is 20%. Compared with Example 1, the bending resistance, abrasion resistance, and mechanical properties are significantly reduced because the unmodified Pleurotus eryngii micropowder has poor interfacial compatibility with polyurethane, resulting in more defects inside the leather products.

[0061] Comparative Example 2

[0062] The only difference from Example 1 is that the moisture content in step (1) is vacuum dried to 0.03%, while the other parameters and conditions are the same as in Example 1, to produce bio-based leather products.

[0063] The amount of *Pleurotus ostreatus* fruiting bodies and the content of bio-based components in the leather products prepared in this comparative example are basically the same as those in Example 1, at 71.5% and 86%, respectively. The water vapor permeability was measured to be 2.7 mg / cm³. 2 The flexural strength is 14,000 cycles, the abrasion resistance is 900 cycles, the tensile strength is 28 MPa, and the elongation at break is 45%. The high moisture content of the fruiting body, *Pleurotus ostreatus*, consumes some isocyanate during in-situ polymerization with polyurethane monomers, reducing the molecular weight of the final polyurethane and thus affecting the overall performance of the final leather products.

[0064] Comparative Example 3

[0065] The only difference from Example 1 is that the 300-mesh sieve in step (1) is replaced with a 50-mesh sieve. All other parameters and conditions are the same as in Example 1, and bio-based leather products are made.

[0066] The amount of *Pleurotus ostreatus* fruiting body and the content of bio-based components in the bio-based leather product prepared in this comparative example are basically the same as those in Example 1, at 71.5% and 86%, respectively. The water vapor permeability was measured to be 2.3 mg / cm³. 2 The product has a bending resistance of 10,000 cycles, an abrasion resistance of 800 cycles, a tensile strength of 12 MPa, and an elongation at break of 20%. The main reason for the performance degradation is that the large fruiting bodies of king oyster mushrooms are prone to forming defects in the finished product, leading to a decline in overall performance.

[0067] Comparative Example 4

[0068] The only difference from Example 1 is that the modified viscose short fibers in step (2) are replaced with unmodified viscose short fibers. All other parameters and conditions are the same as in Example 1, and bio-based leather products are made.

[0069] The amount of *Pleurotus ostreatus* fruiting bodies and the content of bio-based components in the leather products prepared in this comparative example are basically the same as those in Example 1, at 71.5% and 86%, respectively. The water vapor permeability was measured to be 2.6 mg / cm³. 2 The viscose staple fiber has a bending resistance of 15,000 cycles, an abrasion resistance of 1,000 cycles, a tensile strength of 22 MPa, and an elongation at break of 45%. In bio-based leather products, viscose staple fibers mainly function as abrasion-resistant and reinforcing agents. However, unmodified viscose staple fibers have poor interfacial compatibility with polyurethane, and direct addition will significantly reduce their effectiveness.

[0070] Comparative Example 5

[0071] The only difference from Example 1 is that the king oyster mushroom in step (1) is replaced with coffee grounds powder. All other parameters and conditions are the same as in Example 1, and bio-based leather products are made.

[0072] The coffee grounds filling amount and bio-based component content in the leather products prepared in this comparative example are basically the same as those in Example 1, at 71.5% and 86%, respectively, and the water vapor permeability is measured to be 0.8 mg / cm³. 2 The product has a bending resistance of 9000 cycles, an abrasion resistance of 500 cycles, a tensile strength of 12 MPa, and an elongation at break of 18%. Although both coffee grounds and fruiting bodies are natural biomass materials, their composition and properties differ significantly. Coffee grounds are primarily composed of hemicellulose and cellulose, and are denser, while fruiting bodies are mainly composed of polysaccharides and amino acids, and are lighter and more porous. The superior water permeability of fruiting bodies in leather products stems from both their hydrophilic properties and porous structure, unlike coffee grounds. Furthermore, the greater density of coffee grounds makes uniform dispersion in PU more difficult than that of fruiting bodies, leading to aggregation of coffee grounds within the PU and a significant decrease in the overall performance of the final leather product.

[0073] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing bio-based leather using fungal fruiting bodies combined with in-situ reactions, characterized in that, The method includes the following steps: (1) The fungal fruiting bodies are reacted in situ under the action of lactide and catalyst to form surface-modified fungal fruiting bodies, which are then dried to a moisture content of 0.001~0.01%, pulverized and sieved to obtain fine powder of modified fungal fruiting bodies; The sieve mesh size is 200-300 mesh; (2) The modified fungal fruiting body fine powder obtained in step (1) is mixed with polyurethane synthetic monomer solution and modified cellulose, and stirred to react; the reacted solution is cast, solvent removed, and dried to obtain leather base; The modified cellulose is modified viscose short fiber; the preparation of the modified viscose short fiber includes the following steps: Unmodified viscose staple fibers are dried in an oven to remove moisture, then added to molten lactide, followed by stannous octoate catalyst, and reacted at 100-120°C for 2-5 hours. The viscose staple fibers are then removed, and the ungrafted polylactic acid components on the surface of the viscose staple fibers are removed with dichloromethane to obtain modified viscose fibers with polylactic acid segments grafted onto the surface. (3) The leather base prepared in step (2) is polished, laminated and embossed according to the conventional microfiber leather processing method to obtain the bio-based leather finished product.

2. The method according to claim 1, characterized in that, The fungal fruiting bodies mentioned in step (1) include one or more of the following: enoki mushroom, tea tree mushroom, king oyster mushroom, white jade mushroom, lion's mane mushroom, morel mushroom, or northern wind mushroom.

3. The method according to claim 1, characterized in that, The in-situ reaction in step (1) specifically refers to mixing fungal fruiting bodies with lactide and catalyst, and carrying out an in-situ reaction at 100~120℃; through the in-situ ring-opening polymerization of lactide on the surface of fungal fruiting bodies, the surface grafting modification of fungal fruiting bodies by polylactic acid molecular chain segments is achieved.

4. The method according to claim 1, characterized in that, The polyurethane monomer solution described in step (1) is formed by mixing DMF as solvent with oligomeric diol, chain extender and isocyanate.

5. The method according to claim 1, characterized in that, The modified cellulose fiber in step (2) has a length of 5-10 mm and is added at 10-50% of the dry weight of the fungal fruiting body fine powder, w / w.

6. The method according to claim 1, characterized in that, The stirring reaction temperature in step (2) is 80-120℃, and the reaction time is 2-5h.

7. Bio-based leather prepared by the method according to any one of claims 1 to 6.

8. The application of the bio-based leather according to claim 7 in the preparation of bags, footwear, and decorations.