A biodegradable nonwoven fabric made from the entire branch of mulberry and its preparation method

Abstract

This invention provides a biodegradable nonwoven fabric utilizing whole mulberry branches and its preparation method, belonging to the field of nonwoven fabric preparation technology. The method of this invention includes the following steps: (1) removing impurities from collected whole mulberry branches and then cutting and crushing them to obtain fragments; (2) softening the fragments to obtain softened material; (3) repeatedly rinsing the softened material with clean water, and then dehydrating and drying it to obtain dried material; (4) sequentially opening and combing the dried material to obtain mulberry branch fibers; (5) sequentially modifying, web-forming, needle-punching and heat-setting the mulberry branch fibers to obtain biodegradable nonwoven fabric utilizing whole mulberry branches. The nonwoven fabric provided by this invention has the characteristics of high resource utilization rate, biodegradability, environmental protection and no pollution, and excellent toughness and wear resistance.

Description

Technical Field

[0001] This invention relates to the field of nonwoven fabric preparation technology, specifically to a biodegradable nonwoven fabric made from whole mulberry branches and its preparation method. Background Technology

[0002] As a major producer of mulberry trees and silkworms, my country generates a huge amount of waste mulberry branches every year. Currently, the majority of these waste branches are disposed of through open burning, indiscriminate dumping, or simple landfilling. This not only results in a massive waste of biomass resources but also causes a series of environmental problems such as air, soil, and water pollution, contradicting the current development concepts of green, low-carbon, and circular economy. Improving the utilization rate of mulberry branch resources is an urgent technical problem that needs to be solved at this stage.

[0003] However, there are still many problems in the resource utilization of mulberry branches.

[0004] Firstly, when mulberry branches are used in the textile fiber field, the phloem and xylem of the branches need to be strictly separated. Only the long fibers of the phloem are selected as textile raw materials, while the xylem is directly discarded or used only for low-value-added purposes such as fuel and filler. The comprehensive utilization rate of raw materials is extremely low, and the problem of resource waste is prominent.

[0005] Secondly, traditional mulberry branch fiber processing generally uses a high-temperature alkaline boiling softening method, which not only consumes a lot of energy but also produces a large amount of alkaline wastewater. The subsequent wastewater treatment is costly and difficult, and it is very easy to cause secondary pollution to the surrounding environment.

[0006] Thirdly, nonwoven fabrics made from mulberry branches have advantages such as biodegradability, renewability, and low carbon emissions. However, since the main component of this type of nonwoven fabric is plant fiber, although some plant fibers themselves have high strength, the tensile strength or impact resistance of pure plant fiber nonwoven fabrics is usually not as good as that of chemical fiber nonwoven fabrics of the same weight due to the limitations of the needle-punching process. Compared with petroleum-based chemical fibers such as polypropylene and polyester nonwoven fabrics, plant fiber nonwoven fabrics have relatively low toughness, and the nonwoven fabrics made from them are prone to damage after long-term use and friction.

[0007] Fourth, existing mulberry branch fiber products generally suffer from limited applications, mostly limited to traditional fields such as papermaking and textiles. They cannot meet the diverse needs of urban ecological protection, municipal engineering construction, agricultural seedling cultivation, environmentally friendly packaging and storage, and cultural and creative handicraft training. Overall, their application paths are narrow, their technical limitations are obvious, and their product applicability and marketability are poor.

[0008] Therefore, it is of great significance to provide a biodegradable nonwoven fabric that utilizes the entire mulberry branch, which has high resource utilization, is environmentally friendly, has excellent mechanical properties, and has a wide range of applications. Summary of the Invention

[0009] In view of this, the present invention provides a method for preparing biodegradable nonwoven fabric from whole mulberry branches, comprising the following steps:

[0010] (1) After removing impurities from the collected mulberry branches, cut and crush them to obtain the crushed material;

[0011] (2) Soften the scrap material to obtain softened material;

[0012] (3) Rinse the softened material repeatedly with clean water. After rinsing, dehydrate and dry the material in sequence to obtain the dried material.

[0013] (4) The dried material is sequentially opened and combed to obtain mulberry branch fibers;

[0014] (5) The mulberry branch fibers are modified, laid into a web, needled and reinforced, and heat-set in sequence to obtain biodegradable nonwoven fabric for the whole mulberry branch.

[0015] Furthermore, the impurity removal in step (1) specifically refers to removing impurities such as mud, sand, stones, and metal mixed in the material to ensure the stability of subsequent production processes.

[0016] Furthermore, the particle size of the crushed material in step (1) is between 3 mm and 8 mm.

[0017] Furthermore, the softening in step (2) employs a bio-enzyme softening technique, wherein the bio-enzyme includes at least one of alkaline pectinase, laccase, and hemicellulase.

[0018] Furthermore, based on the dry weight of the mulberry branch fragments described in step (1), the amount of alkaline pectinase is 120-300 IU / g, the amount of hemicellulase is 200-500 IU / g, and the amount of laccase is 300-500 IU / g.

[0019] Furthermore, in step (2), the alkaline pectinase solution, hemicellulase solution, or laccase solution used in the softening process are all prepared using a buffer solution, the composition of which includes: NaH2PO4·2H2O of 0.8 mmol / L, CaCl2·2H2O of 5 mmol / L, MES of 2.5 mmol / L, and mannitol of 0.3 mmol / L.

[0020] Furthermore, the softening treatment temperature in step (2) is 40℃-60℃, and the treatment time is 1h-2h.

[0021] Furthermore, in step (3), the rinsing process is carried out until the pH value of the material system is stable between 6.5 and 8.5; in step (3), the dehydration process is carried out until the moisture content of the material is between 40% and 50%; in step (3), the drying temperature is 80℃ to 90℃, and the moisture content of the material after drying is maintained between 10% and 12%.

[0022] Furthermore, the length of the mulberry branch fiber in step (4) is between 10mm and 30mm; the uniformity of the mulberry branch fiber in step (4) is not less than 90%.

[0023] Furthermore, the needle density in step (5) is set to 80~200 needles / cm². 2 The needle insertion depth is 6mm~12mm, and the needle is inserted repeatedly 3~5 times.

[0024] Furthermore, the heat setting temperature in step (5) is 100℃~110℃.

[0025] Furthermore, the modification process described in step (5) includes the following steps:

[0026] Step 1: Mix chitosan and 1-allyl-3-methylimidazolium chloride to obtain a mixture; heat and stir the mixture in an oil bath at 75-85°C until the chitosan is fully dissolved; then add 3-chloro-2-hydroxypropyltrimethylammonium chloride under ultrasonic conditions, continue stirring for 3-5 hours, add ethanol to precipitate, allow to stand and separate into layers, filter, wash with acetone, and dry to obtain chitosan quaternary ammonium salt;

[0027] Step 2: Dissolve the chitosan quaternary ammonium salt in an appropriate amount of deionized water to obtain a chitosan quaternary ammonium salt solution; add triethylamine to the chitosan quaternary ammonium salt solution to adjust the pH of the system to 8.0-8.5, then add 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate, and stir rapidly until fully dispersed. Then raise the temperature of the system to 70-80℃ and stir for 3-5 hours; after the reaction is completed, cool to room temperature, precipitate with ethanol, filter, wash repeatedly with acetone, and dry to obtain modified chitosan quaternary ammonium salt;

[0028] Step 3: Mix the modified chitosan quaternary ammonium salt and deionized water in a certain proportion to obtain a mixed solution; immerse the mulberry branch fibers in the mixed solution at a bath ratio of 1:20-30; after immersion, remove and roll the fibers, dry them, and the modification is complete.

[0029] Furthermore, in step one, the mass ratio of chitosan, 1-allyl-3-methylimidazolium chloride, and 3-chloro-2-hydroxypropyltrimethylammonium chloride is 1:10-25:3-7; the amount of ethanol added is 2-3 times the total mass of the system; and the drying temperature is 60-80℃.

[0030] Furthermore, in step two, the mass ratio of chitosan quaternary ammonium salt to deionized water is 1:20-50; the mass ratio of chitosan quaternary ammonium salt, 2,6-di-tert-butyl-p-cresol, and glycidyl methacrylate is 1:0.01-0.05:0.8-1.2.

[0031] Furthermore, in step three, the concentration of the mixed solution is 10-18 g / L; the impregnation temperature is 50-60℃, and the impregnation time is 1-2 h; the rolling process specifically involves two dips and two rolls with a roll residue of 70-80%; and the drying temperature is 60-70℃, and the drying time is 1-3 h.

[0032] The present invention also provides a biodegradable nonwoven fabric for the whole use of mulberry branches prepared according to the method, and the application of the nonwoven fabric in packaging, agriculture, home furnishing, construction, environmental protection and other fields.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] This invention provides a nonwoven fabric prepared from pure plant fibers, which features high resource utilization, biodegradability, and environmental friendliness. However, pure plant fibers have relatively poor toughness, and the nonwoven fabric prepared from them is prone to wear and damage after long-term use and friction. To address this, this invention introduces glycidyl methacrylate, utilizing the reaction between the epoxy groups and the amino or hydroxyl groups of chitosan quaternary ammonium salt to impart crosslinking ability, facilitating the formation of a network structure in subsequent reactions; triethylamine is used as a catalyst, and the pH of the system is adjusted to 8.0-8.5, as an alkaline environment is conducive to the ring-opening reaction of epoxy groups; 2,6-di-tert-butyl-p-cresol is used as a stabilizer to prevent premature polymerization of glycidyl methacrylate during the reaction, thereby improving the success rate of modification.

[0035] In this invention, modified chitosan quaternary ammonium salt reacts chemically with mulberry branch fibers to form hydrogen bonds, salt bonds, van der Waals forces, and other forces, making the internal structure of mulberry branch fiber molecules more compact. Under external stretching or friction, the macromolecular chains are less likely to break, thus improving the breaking strength of mulberry branch fibers and thereby enhancing the toughness and wear resistance of biodegradable nonwoven fabric made from whole mulberry branches. Detailed Implementation

[0036] This invention provides a method for preparing biodegradable nonwoven fabric from whole mulberry branches, comprising the following steps:

[0037] (1) After removing impurities from the collected mulberry branches, cut and crush them to obtain the crushed material;

[0038] (2) Soften the scrap material to obtain softened material;

[0039] (3) Rinse the softened material repeatedly with clean water. After rinsing, dehydrate and dry the material in sequence to obtain the dried material.

[0040] (4) The dried material is sequentially opened and combed to obtain mulberry branch fibers;

[0041] (5) The mulberry branch fibers are modified, laid into a web, needled and reinforced, and heat-set in sequence to obtain biodegradable nonwoven fabric for the whole mulberry branch.

[0042] In some embodiments of the present invention, the impurity removal in step (1) specifically refers to removing impurities such as mud, sand, stones, and metal mixed in the material to ensure the stability of subsequent production processes.

[0043] In some embodiments of the present invention, the particle size of the crushed material in step (1) is between 3 mm and 8 mm.

[0044] This invention does not impose any special limitations on the crushing equipment or method, as long as it can crush the material to a particle size range of 3mm-8mm. Applicable crushing equipment includes, but is not limited to, roller crushers, hammer crushers, impact crushers, ultrafine pulverizers, and ball mills. Preferably, this invention uses an ultrafine pulverizer for crushing.

[0045] In some embodiments of the present invention, the softening in step (2) is performed using a bio-enzyme softening technique, wherein the bio-enzyme includes at least one of alkaline pectinase, laccase, and hemicellulase.

[0046] In some embodiments of the present invention, based on the dry weight of the mulberry branch fragments in step (1), the amount of alkaline pectinase is 120-300 IU / g, the amount of hemicellulase is 200-500 IU / g, and the amount of laccase is 300-500 IU / g.

[0047] In some embodiments of the present invention, the alkaline pectinase solution, hemicellulase solution, or laccase solution used in step (2) for softening are all prepared using a buffer solution. The buffer solution comprises: 0.8 mmol / L NaH2PO4·2H2O, 5 mmol / L CaCl2·2H2O, 2.5 mmol / L MES, and 0.3 mmol / L mannitol. The prepared buffer solution is placed in an autoclave and treated at 121°C under high pressure for 15-30 minutes to kill any microorganisms that may be present in the buffer solution, including bacteria, fungi, spores, etc., to ensure a sterile environment.

[0048] In some embodiments of the present invention, the softening treatment temperature in step (2) is 40℃-60℃ and the treatment time is 1h-2h. The fibers are fully softened and dispersed under low temperature and mild conditions, without the need for the traditional high temperature alkaline boiling process.

[0049] In some embodiments of the present invention, the rinsing in step (3) is performed until the pH value of the material system is stable between 6.5 and 8.5; the dehydration in step (3) is performed until the moisture content of the material is between 40% and 50%; the drying temperature in step (3) is 80℃ to 90℃, and the moisture content of the material after drying is maintained between 10% and 12%.

[0050] In some embodiments of the present invention, the length of the mulberry branch fiber in step (4) is between 10 mm and 30 mm; the uniformity of the mulberry branch fiber in step (4) is not less than 90%.

[0051] In some embodiments of the present invention, the needle density in step (5) is set to 80~200 needles / cm. 2 The needle-punching depth is 6mm~12mm, and the needle-punching is repeated 3~5 times to fully entangle and bind the fibers together, thereby improving the overall structural stability and mechanical strength of the nonwoven fabric.

[0052] In some embodiments of the present invention, the heat setting temperature in step (5) is 100°C to 110°C, which is used to eliminate internal stress and ensure product shape stability.

[0053] Finally, the branches are cut into different sizes according to usage requirements to obtain biodegradable nonwoven fabric products that utilize the entire mulberry branch.

[0054] In some embodiments of the present invention, the modification process described in step (5) includes the following steps:

[0055] Step 1: Mix chitosan and 1-allyl-3-methylimidazolium chloride to obtain a mixture; heat and stir the mixture in an oil bath at 75-85°C until the chitosan is fully dissolved; then add 3-chloro-2-hydroxypropyltrimethylammonium chloride under ultrasonic conditions, continue stirring for 3-5 hours, add ethanol to precipitate, allow to stand and separate into layers, filter, wash with acetone, and dry to obtain chitosan quaternary ammonium salt;

[0056] Step 2: Dissolve the chitosan quaternary ammonium salt in an appropriate amount of deionized water to obtain a chitosan quaternary ammonium salt solution; add triethylamine to the chitosan quaternary ammonium salt solution to adjust the pH of the system to 8.0-8.5, then add 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate, and stir rapidly until fully dispersed. Then raise the temperature of the system to 70-80℃ and stir for 3-5 hours; after the reaction is completed, cool to room temperature, precipitate with ethanol, filter, wash repeatedly with acetone, and dry to obtain modified chitosan quaternary ammonium salt;

[0057] Step 3: Mix the modified chitosan quaternary ammonium salt and deionized water in a certain proportion to obtain a mixed solution; immerse the mulberry branch fibers in the mixed solution at a bath ratio of 1:20-30; after immersion, remove and roll the fibers, dry them, and the modification is complete.

[0058] In some embodiments of the present invention, the mass ratio of chitosan, 1-allyl-3-methylimidazolium chloride, and 3-chloro-2-hydroxypropyltrimethylammonium chloride in step one is 1:10-25:3-7; the amount of ethanol added is 2-3 times the total mass of the system; and the drying temperature is 60-80°C.

[0059] In some embodiments of the present invention, the 3-chloro-2-hydroxypropyltrimethylammonium chloride in step one is added in two parts: half of the total amount is added after 1 hour of reaction, and the remaining amount is added after 2.5 hours of reaction. The purpose is to prevent the 3-chloro-2-hydroxypropyltrimethylammonium chloride from decomposing too quickly in the reaction system, so as to make the reaction more complete.

[0060] In some embodiments of the present invention, the mass ratio of chitosan quaternary ammonium salt to deionized water in step two is 1:20-50; the mass ratio of chitosan quaternary ammonium salt, 2,6-di-tert-butyl-p-cresol, and glycidyl methacrylate is 1:0.01-0.05:0.8-1.2.

[0061] In some embodiments of the present invention, the concentration of the mixed solution in step three is 10-18 g / L; the impregnation temperature is 50°C and the impregnation time is 1-2 h; the rolling process specifically involves two dips and two rolls with a roll residue of 70-80%; and the drying temperature is 60-70°C and the drying time is 1-3 h.

[0062] This invention also provides a biodegradable nonwoven fabric for the whole-branch utilization of mulberry branches prepared according to the method, and the application of the nonwoven fabric in packaging, agriculture, home furnishing, construction, and environmental protection. Applications in the packaging field include, but are not limited to, milk tea bags, eco-friendly bags, and shopping bags; applications in the agricultural and environmental protection field include, but are not limited to, greening protection fabric, seedling pots, lawn reinforcement netting, agricultural ground cover, and winter protection fabric; applications in the home furnishing field include, but are not limited to, stationery and creative products, coasters, and mattress linings; and applications in the construction field include, but are not limited to, urban bare soil covering materials and temporary protection materials for road construction.

[0063] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0064] Unless otherwise specified, the test methods or experimental methods described in the following examples are all conventional methods; unless otherwise specified, the raw materials and additives are obtained from conventional commercial sources or prepared by conventional methods.

[0065] In the following examples or comparative examples, the buffer solution composition is as follows: NaH₂PO₄·2H₂O 0.8 mmol / L, CaCl₂·2H₂O 5 mmol / L, MES (2-morpholinoethanesulfonic acid) 2.5 mmol / L, and mannitol 0.3 mmol / L. The prepared buffer solution was placed in an autoclave and treated at 121°C under high pressure for 20 min. After the buffer solution was autoclaved and cooled to room temperature, a biological enzyme was added.

[0066] The chitosan has a molecular weight of approximately 700,000 and a degree of deacetylation of approximately 85%, and was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0067] This invention uses an ultrafine pulverizer for pulverization.

[0068] Example 1

[0069] A method for preparing biodegradable nonwoven fabric from whole mulberry branches, the specific steps of which are as follows:

[0070] (1) Use the collected whole mulberry branches as raw materials, control the moisture content at 10%, remove impurities, and cut and crush the raw materials to 5mm to obtain crushed materials;

[0071] (2) Add alkaline pectinase solution to the crushed material. The amount of alkaline pectinase is 180 IU / g based on the dry weight of the crushed material. The alkaline pectinase solution is prepared with buffer solution. Soften the crushed material at 50°C for 1.5h to obtain the softened material.

[0072] (3) Use clean water to repeatedly rinse the softened material until the pH value of the material system is 7.5. After rinsing, dehydrate the material until the moisture content is 45%, and dry it at 80℃ to obtain a material with a moisture content of 11%.

[0073] (4) The material is opened and mixed using an opening machine, and then combed to obtain mulberry branch fibers with a length of 20mm;

[0074] (5) The mulberry branch fibers are modified. After modification, a web-laying machine is used to lay the web. The web is treated at 700℃ for 50 minutes and then spunbonded using a twin-roll hot rolling mill. The roller temperature of the twin-roll hot rolling mill is 135℃. The roller surface of the twin-roll hot rolling mill has needle-like burrs with a burr length of 0.1 mm. After cooling and winding, 60 g / m² is obtained. 2Thin nonwoven fabric, needle-punched and reinforced, needle density 120 needles / cm 2 The needle is punctured to a depth of 10mm, and the needle is punctured 5 times. The needle is then heat-set and cut at 105℃ to obtain biodegradable nonwoven fabric for the whole mulberry branch.

[0075] The modification process described in step (5) is as follows:

[0076] Step 1: Chitosan and 1-allyl-3-methylimidazolium chloride are mixed to obtain a mixture. The mixture is heated and stirred in an oil bath at 80°C until the chitosan is fully dissolved. Then, under ultrasonic conditions, 3-chloro-2-hydroxypropyltrimethylammonium chloride is added (the order of addition is: half of the total amount of 3-chloro-2-hydroxypropyltrimethylammonium chloride is added at the beginning of the reaction, and the remaining part is added after 2.5 h of reaction). The mass ratio of chitosan, 1-allyl-3-methylimidazolium chloride, and 3-chloro-2-hydroxypropyltrimethylammonium chloride is 1:16:5. The mixture is stirred for 4 h. After stirring, ethanol is added to precipitate the mixture. The amount of ethanol added is twice the total mass of the system. The mixture is allowed to stand and separate into layers, filtered, washed with acetone, and dried at 60°C for 5 h to obtain chitosan quaternary ammonium salt.

[0077] Step 2: Dissolve the chitosan quaternary ammonium salt in an appropriate amount of deionized water to obtain a chitosan quaternary ammonium salt solution, wherein the mass ratio of chitosan quaternary ammonium salt to deionized water is 1:33; add triethylamine to the chitosan quaternary ammonium salt solution to adjust the pH of the system to 8.0, then add 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate, wherein the mass ratio of chitosan quaternary ammonium salt, 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate is 1:0.02:0.8, and stir rapidly until fully dispersed. Then raise the system temperature to 70°C and stir for 3 hours; after the reaction is completed, cool to room temperature, precipitate with ethanol, filter, wash repeatedly with acetone, and dry at 60°C for 2 hours to obtain modified chitosan quaternary ammonium salt;

[0078] Step 3: Mix the modified chitosan quaternary ammonium salt and deionized water in a certain proportion to obtain a mixed solution with a concentration of 15 g / L; immerse the mulberry branch fibers in the mixed solution at an immersion temperature of 50°C for 2 hours at a liquor ratio of 1:30. After immersion, remove the fibers and roll them using a two-dip, two-roll process with a roll residue of 80%. Then, place the fibers in a 70°C vacuum drying oven for 3 hours to complete the modification.

[0079] Example 2

[0080] A method for preparing biodegradable nonwoven fabric from whole mulberry branches, the specific steps of which are as follows:

[0081] (1) Use the collected whole mulberry branches as raw materials, control the moisture content at 12%, remove impurities, and cut and crush the raw materials to 5mm to obtain crushed materials;

[0082] (2) Add alkaline pectinase solution to the crushed material. The amount of alkaline pectinase is 120 IU / g based on the dry weight of the crushed material. The alkaline pectinase solution is prepared with buffer solution. Soften the crushed material at 40℃ for 2 hours to obtain the softened material.

[0083] (3) Use clean water to repeatedly rinse the softened material until the pH value of the material system is 6.5. After rinsing, dehydrate the material until the moisture content is 50%, and dry it at 80℃ to obtain a material with a moisture content of 10%.

[0084] (4) The material is opened and mixed using an opening machine, and then combed to obtain mulberry branch fibers with a length of 10mm.

[0085] (5) The mulberry branch fibers are modified. After modification, a web-laying machine is used to lay the web. The web is treated at 700℃ for 50 minutes and then spunbonded using a twin-roll hot rolling mill. The roller temperature of the twin-roll hot rolling mill is 135℃. The roller surface of the twin-roll hot rolling mill has needle-like burrs with a burr length of 0.1 mm. After cooling and winding, 60 g / m² is obtained. 2 Thin nonwoven fabric, needle-punched and reinforced, needle density 80 needles / cm 2 The needle is punctured to a depth of 12mm, and the needle is punctured repeatedly 5 times. The needle is then heat-set and cut at 100℃ to obtain biodegradable nonwoven fabric for the whole mulberry branch.

[0086] The modification process described in step (5) is as follows:

[0087] Step 1: Chitosan and 1-allyl-3-methylimidazolium chloride are mixed to obtain a mixture. The mixture is heated and stirred in an oil bath at 75°C until the chitosan is fully dissolved. Then, under ultrasonic conditions, 3-chloro-2-hydroxypropyltrimethylammonium chloride is added (the order of addition is: half of the total amount of 3-chloro-2-hydroxypropyltrimethylammonium chloride is added at the beginning of the reaction, and the remaining part is added after 2.5 h of reaction). The mass ratio of chitosan, 1-allyl-3-methylimidazolium chloride, and 3-chloro-2-hydroxypropyltrimethylammonium chloride is 1:10:3. The mixture is stirred for 3 h. After stirring, ethanol is added to precipitate the mixture. The amount of ethanol added is twice the total mass of the system. The mixture is allowed to stand and separate into layers, filtered, washed with acetone, and dried at 60°C for 5 h to obtain chitosan quaternary ammonium salt.

[0088] Step 2: Dissolve the chitosan quaternary ammonium salt in an appropriate amount of deionized water to obtain a chitosan quaternary ammonium salt solution, wherein the mass ratio of chitosan quaternary ammonium salt to deionized water is 1:20; add triethylamine to the chitosan quaternary ammonium salt solution to adjust the pH of the system to 8.0, then add 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate, wherein the mass ratio of chitosan quaternary ammonium salt, 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate is 1:0.01:0.8, and stir rapidly until fully dispersed. Then raise the system temperature to 70°C and stir for 3 hours; after the reaction is completed, cool to room temperature, precipitate with ethanol, filter, wash repeatedly with acetone, and dry at 60°C for 2 hours to obtain modified chitosan quaternary ammonium salt;

[0089] Step 3: Mix the modified chitosan quaternary ammonium salt and deionized water in a certain proportion to obtain a mixed solution with a concentration of 10 g / L; immerse the mulberry branch fibers in the mixed solution at an immersion temperature of 50°C for 1 hour at a liquor ratio of 1:20. After immersion, remove and roll the fibers using a two-dip, two-roll process with a roll residue of 70%. Then, place the fibers in a vacuum drying oven at 60°C for 3 hours to dry them under vacuum. The modification is then complete.

[0090] Example 3

[0091] A method for preparing biodegradable nonwoven fabric from whole mulberry branches, the specific steps of which are as follows:

[0092] (1) Use the collected whole mulberry branches as raw materials, control the moisture content at 12%, remove impurities, and cut and crush the raw materials to 5mm to obtain crushed materials;

[0093] (2) Add alkaline pectinase solution to the crushed material. The amount of alkaline pectinase is 150 IU / g based on the dry weight of the crushed material. The alkaline pectinase solution is prepared with buffer solution. Soften the crushed material at 40℃ for 1 hour to obtain the softened material.

[0094] (3) Use clean water to repeatedly rinse the softened material until the pH value of the material system is 6.8. After rinsing, dehydrate the material until the moisture content is 45%, and dry it at 80°C to obtain a material with a moisture content of 10%.

[0095] (4) The material is opened and mixed using an opening machine, and then combed to obtain mulberry branch fibers with a length of 15mm.

[0096] (5) The mulberry branch fibers are modified. After modification, a web-laying machine is used to lay the web. The web is treated at 700℃ for 50 minutes and then spunbonded using a twin-roll hot rolling mill. The roller temperature of the twin-roll hot rolling mill is 135℃. The roller surface of the twin-roll hot rolling mill has needle-like burrs with a burr length of 0.1 mm. After cooling and winding, 60 g / m² is obtained. 2Thin nonwoven fabric, needle-punched and reinforced, needle density 100 needles / cm 2 The needle is punctured to a depth of 7mm, and the needle is punctured three times. The needle is then heat-set and cut at 100℃~110℃ to obtain biodegradable nonwoven fabric for the whole mulberry branch.

[0097] The modification process described in step (5) is as follows:

[0098] Step 1: Chitosan and 1-allyl-3-methylimidazolium chloride are mixed to obtain a mixture. The mixture is heated and stirred in an oil bath at 75°C until the chitosan is fully dissolved. Then, under ultrasonic conditions, 3-chloro-2-hydroxypropyltrimethylammonium chloride is added (the order of addition is: half of the total amount of 3-chloro-2-hydroxypropyltrimethylammonium chloride is added at the beginning of the reaction, and the remaining part is added after 2.5 h of reaction). The mass ratio of chitosan, 1-allyl-3-methylimidazolium chloride, and 3-chloro-2-hydroxypropyltrimethylammonium chloride is 1:15:3. The mixture is stirred for 3 h. After stirring, ethanol is added to precipitate the mixture. The amount of ethanol added is twice the total mass of the system. The mixture is allowed to stand and separate into layers, filtered, washed with acetone, and dried at 65°C for 2 h to obtain chitosan quaternary ammonium salt.

[0099] Step 2: Dissolve the chitosan quaternary ammonium salt in an appropriate amount of deionized water to obtain a chitosan quaternary ammonium salt solution, wherein the mass ratio of chitosan quaternary ammonium salt to deionized water is 1:25; add triethylamine to the chitosan quaternary ammonium salt solution to adjust the pH of the system to 8.0, then add 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate, wherein the mass ratio of chitosan quaternary ammonium salt, 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate is 1:0.02:0.9, and stir rapidly until fully dispersed. Then raise the system temperature to 70°C and stir for 5 hours; after the reaction is completed, cool to room temperature, precipitate with ethanol, filter, wash repeatedly with acetone, and dry at 60°C for 2 hours to obtain modified chitosan quaternary ammonium salt;

[0100] Step 3: Mix the modified chitosan quaternary ammonium salt and deionized water in a certain proportion to obtain a mixed solution with a concentration of 12 g / L; immerse the mulberry branch fibers in the mixed solution at an immersion temperature of 50°C for 1 hour at a liquor ratio of 1:30. After immersion, remove the fibers and roll them using a two-dip, two-roll process with a roll residue of 80%. Then, place the fibers in a vacuum drying oven at 60°C for 4 hours to dry them under vacuum. The modification is then complete.

[0101] Example 4

[0102] A method for preparing biodegradable nonwoven fabric from whole mulberry branches, the specific steps of which are as follows:

[0103] (1) Use the collected whole mulberry branches as raw materials, control the moisture content at 11%, remove impurities, and cut and crush the raw materials to 5mm to obtain the crushed material;

[0104] (2) Add alkaline pectinase solution to the crushed material. The amount of alkaline pectinase is 200 IU / g based on the dry weight of the crushed material. The alkaline pectinase solution is prepared with buffer solution. Soften the crushed material at 40°C for 1 hour to obtain the softened material.

[0105] (3) Use clean water to repeatedly rinse the softened material until the pH value of the material system is 6.8. After rinsing, dehydrate the material until the moisture content is 40%, and dry it at 80℃ to obtain a material with a moisture content of 10%.

[0106] (4) The material is opened and mixed using an opening machine, and then combed to obtain mulberry branch fibers with a length of 20mm;

[0107] (5) The mulberry branch fibers are modified. After modification, a web-laying machine is used to lay the web. The web is treated at 700℃ for 50 minutes and then spunbonded using a twin-roll hot rolling mill. The roller temperature of the twin-roll hot rolling mill is 135℃. The roller surface of the twin-roll hot rolling mill has needle-like burrs with a burr length of 0.1 mm. After cooling and winding, 60 g / m² is obtained. 2 Thin nonwoven fabric, needle-punched and reinforced, needle density 180 needles / cm 2 The needle is punctured to a depth of 12mm, and the needle is punctured repeatedly 5 times. The needle is then heat-set and cut at 100℃ to obtain biodegradable nonwoven fabric for the whole mulberry branch.

[0108] The modification process described in step (5) is as follows:

[0109] Step 1: Chitosan and 1-allyl-3-methylimidazolium chloride are mixed to obtain a mixture. The mixture is heated and stirred in an oil bath at 75°C until the chitosan is fully dissolved. Then, under ultrasonic conditions, 3-chloro-2-hydroxypropyltrimethylammonium chloride is added (the order of addition is: half of the total amount of 3-chloro-2-hydroxypropyltrimethylammonium chloride is added at the beginning of the reaction, and the remaining part is added after 2.5 h of reaction). The mass ratio of chitosan, 1-allyl-3-methylimidazolium chloride, and 3-chloro-2-hydroxypropyltrimethylammonium chloride is 1:17:5. The mixture is stirred for 3 h. After stirring, ethanol is added to precipitate the mixture. The amount of ethanol added is twice the total mass of the system. The mixture is allowed to stand and separate into layers, filtered, washed with acetone, and dried at 80°C for 2 h to obtain chitosan quaternary ammonium salt.

[0110] Step 2: Dissolve the chitosan quaternary ammonium salt in an appropriate amount of deionized water to obtain a chitosan quaternary ammonium salt solution, wherein the mass ratio of chitosan quaternary ammonium salt to deionized water is 1:35; add triethylamine to the chitosan quaternary ammonium salt solution to adjust the pH of the system to 8.0, then add 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate, wherein the mass ratio of chitosan quaternary ammonium salt, 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate is 1:0.03:0.8, and stir rapidly until fully dispersed. Then raise the system temperature to 70°C and stir for 5 hours; after the reaction is completed, cool to room temperature, precipitate with ethanol, filter, wash repeatedly with acetone, and dry at 60°C for 2 hours to obtain modified chitosan quaternary ammonium salt;

[0111] Step 3: Mix the modified chitosan quaternary ammonium salt and deionized water in a certain proportion to obtain a mixed solution with a concentration of 10 g / L; immerse the mulberry branch fibers in the mixed solution at an immersion temperature of 50°C for 2 hours at a liquor ratio of 1:30. After immersion, remove the fibers and roll them using a two-dip, two-roll process with a roll residue of 80%. Then, place the fibers in a 70°C vacuum drying oven for 3 hours to complete the modification.

[0112] Example 5

[0113] A method for preparing biodegradable nonwoven fabric from whole mulberry branches, the specific steps of which are as follows:

[0114] (1) Use the collected whole mulberry branches as raw materials, control the moisture content at 13%, remove impurities, and cut and crush the raw materials to 6mm to obtain crushed materials;

[0115] (2) Add alkaline pectinase solution to the crushed material. The amount of alkaline pectinase is 220 IU / g based on the dry weight of the crushed material. The alkaline pectinase solution is prepared with buffer solution. Soften the crushed material at 60°C for 1 hour to obtain the softened material.

[0116] (3) Use clean water to repeatedly rinse the softened material until the pH value of the material system is 8.5. After rinsing, dehydrate the material until the moisture content is 50%, and dry it at 90℃ to obtain a material with a moisture content of 12%.

[0117] (4) The material is opened and mixed using an opening machine, and then combed to obtain mulberry branch fibers with a length of 28mm;

[0118] (5) The mulberry branch fibers are modified. After modification, a web-laying machine is used to lay the web. The web is treated at 700℃ for 50 minutes and then spunbonded using a twin-roll hot rolling mill. The roller temperature of the twin-roll hot rolling mill is 135℃. The roller surface of the twin-roll hot rolling mill has needle-like burrs with a burr length of 0.1 mm. After cooling and winding, 60 g / m² is obtained. 2Thin nonwoven fabric, needle-punched and reinforced, needle density 180 needles / cm 2 The needle is punctured to a depth of 10mm, and the needle is punctured three times. The needle is then heat-set and cut at 100℃~110℃ to obtain biodegradable nonwoven fabric for the whole mulberry branch.

[0119] The modification process described in step (5) is as follows:

[0120] Step 1: Chitosan and 1-allyl-3-methylimidazolium chloride are mixed to obtain a mixture. The mixture is heated and stirred in an oil bath at 80°C until the chitosan is fully dissolved. Then, under ultrasonic conditions, 3-chloro-2-hydroxypropyltrimethylammonium chloride is added (the order of addition is: half of the total amount of 3-chloro-2-hydroxypropyltrimethylammonium chloride is added at the beginning of the reaction, and the remaining part is added after 2.5 h of reaction). The mass ratio of chitosan, 1-allyl-3-methylimidazolium chloride, and 3-chloro-2-hydroxypropyltrimethylammonium chloride is 1:23:6. The mixture is stirred for 4 h. After stirring, ethanol is added to precipitate the mixture. The amount of ethanol added is twice the total mass of the system. The mixture is allowed to stand and separate into layers, filtered, washed with acetone, and dried at 80°C for 2 h to obtain chitosan quaternary ammonium salt.

[0121] Step 2: Dissolve the chitosan quaternary ammonium salt in an appropriate amount of deionized water to obtain a chitosan quaternary ammonium salt solution, wherein the mass ratio of chitosan quaternary ammonium salt to deionized water is 1:33; add triethylamine to the chitosan quaternary ammonium salt solution to adjust the pH of the system to 8.0, then add 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate, wherein the mass ratio of chitosan quaternary ammonium salt, 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate is 1:0.04:0.9, and stir rapidly until fully dispersed. Then raise the system temperature to 70°C and stir for 5 hours; after the reaction is completed, cool to room temperature, precipitate with ethanol, filter, wash repeatedly with acetone, and dry at 60°C for 2 hours to obtain modified chitosan quaternary ammonium salt;

[0122] Step 3: Mix the modified chitosan quaternary ammonium salt and deionized water in a certain proportion to obtain a mixed solution with a concentration of 16 g / L; immerse the mulberry branch fibers in the mixed solution at an immersion temperature of 50°C for 2 hours at a liquor ratio of 1:25. After immersion, remove the fibers and roll them using a two-dip, two-roll process with a roll residue of 75%. Then, place the fibers in a 70°C vacuum drying oven for 4 hours to complete the modification.

[0123] Example 6

[0124] A method for preparing biodegradable nonwoven fabric from whole mulberry branches, the specific steps of which are as follows:

[0125] (1) Use the collected whole mulberry branches as raw materials, control the moisture content at 15%, remove impurities, and then cut and crush the raw materials to 8mm to obtain the crushed material;

[0126] (2) Add alkaline pectinase solution to the crushed material. The amount of alkaline pectinase is 280 IU / g based on the dry weight of the crushed material. The alkaline pectinase solution is prepared with buffer solution. Soften the crushed material at 50°C for 1 hour to obtain the softened material.

[0127] (3) Use clean water to repeatedly rinse the softened material until the pH value of the material system is 8.5. After rinsing, dehydrate the material until the moisture content is 50%, and dry it at 90℃ to obtain a material with a moisture content of 12%.

[0128] (4) The material is opened and mixed using an opening machine, and then combed to obtain mulberry branch fibers with a length of 30mm.

[0129] (5) The mulberry branch fibers are modified. After modification, a web-laying machine is used to lay the web. The web is treated at 700℃ for 50 minutes and then spunbonded using a twin-roll hot rolling mill. The roller temperature of the twin-roll hot rolling mill is 135℃. The roller surface of the twin-roll hot rolling mill has needle-like burrs with a burr length of 0.1 mm. After cooling and winding, 60 g / m² is obtained. 2 Thin nonwoven fabric, needle-punched and reinforced, needle density 200 needles / cm² 2 The needle is punctured to a depth of 12mm, and the needle is punctured 5 times. The mulberry tree branch is then heat-set and cut at 110℃ to obtain a biodegradable nonwoven fabric.

[0130] The modification process described in step (5) is as follows:

[0131] Step 1: Chitosan and 1-allyl-3-methylimidazolium chloride are mixed to obtain a mixture. The mixture is heated and stirred in an oil bath at 80°C until the chitosan is fully dissolved. Then, under ultrasonic conditions, 3-chloro-2-hydroxypropyltrimethylammonium chloride is added (the order of addition is: half of the total amount of 3-chloro-2-hydroxypropyltrimethylammonium chloride is added at the beginning of the reaction, and the remaining part is added after 2.5 h of reaction). The mass ratio of chitosan, 1-allyl-3-methylimidazolium chloride, and 3-chloro-2-hydroxypropyltrimethylammonium chloride is 1:25:7. The mixture is stirred for 5 h. After stirring, ethanol is added to precipitate the mixture. The amount of ethanol added is 3 times the total mass of the system. The mixture is allowed to stand and separate into layers, filtered, washed with acetone, and dried at 80°C for 5 h to obtain chitosan quaternary ammonium salt.

[0132] Step 2: Dissolve the chitosan quaternary ammonium salt in an appropriate amount of deionized water to obtain a chitosan quaternary ammonium salt solution, wherein the mass ratio of chitosan quaternary ammonium salt to deionized water is 1:45; add triethylamine to the chitosan quaternary ammonium salt solution to adjust the pH of the system to 8.5, then add 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate, wherein the mass ratio of chitosan quaternary ammonium salt, 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate is 1:0.05:1.2, and stir rapidly until fully dispersed. Then raise the system temperature to 80°C and stir for 5 hours; after the reaction is completed, cool to room temperature, precipitate with ethanol, filter, wash repeatedly with acetone, and dry at 60°C for 2 hours to obtain modified chitosan quaternary ammonium salt;

[0133] Step 3: Mix the modified chitosan quaternary ammonium salt and deionized water in a certain proportion to obtain a mixed solution with a concentration of 7 g / L; immerse the mulberry branch fibers in the mixed solution at an immersion temperature of 50°C for 2 hours at a liquor ratio of 1:30. After immersion, remove the fibers and roll them using a two-dip, two-roll process with a roll residue of 80%. Then, place the fibers in a 70°C vacuum drying oven for 5 hours to complete the modification.

[0134] Example 7

[0135] A method for preparing biodegradable nonwoven fabric from whole mulberry branches, the specific steps of which are as follows:

[0136] (1) Use the collected whole mulberry branches as raw materials, control the moisture content at 10%, remove impurities, and cut and crush the raw materials to 3mm to obtain crushed materials;

[0137] (2) Add alkaline pectinase solution to the crushed material. The amount of alkaline pectinase is 300 IU / g based on the dry weight of the crushed material. The alkaline pectinase solution is prepared with buffer solution. Soften the crushed material at 60°C for 2 hours to obtain the softened material.

[0138] (3) Use clean water to repeatedly rinse the softened material until the pH value of the material system is 8.5. After rinsing, dehydrate the material until the moisture content is 50%, and dry it at 90℃ to obtain a material with a moisture content of 12%.

[0139] (4) The material is opened and mixed using an opening machine, and then combed to obtain mulberry branch fibers with a length of 30mm.

[0140] (5) The mulberry branch fibers are modified. After modification, a web-laying machine is used to lay the web. The web is treated at 700℃ for 50 minutes and then spunbonded using a twin-roll hot rolling mill. The roller temperature of the twin-roll hot rolling mill is 135℃. The roller surface of the twin-roll hot rolling mill has needle-like burrs with a burr length of 0.1 mm. After cooling and winding, 60 g / m² is obtained. 2Thin nonwoven fabric, needle-punched and reinforced, needle density 200 needles / cm² 2 The needle is punctured to a depth of 12mm, and the needle is punctured 5 times. The mulberry tree branch is then heat-set and cut at 110℃ to obtain a biodegradable nonwoven fabric.

[0141] The modification process described in step (5) is as follows:

[0142] Step 1: Chitosan and 1-allyl-3-methylimidazolium chloride are mixed to obtain a mixture. The mixture is heated and stirred in an oil bath at 85°C until the chitosan is fully dissolved. Then, under ultrasonic conditions, 3-chloro-2-hydroxypropyltrimethylammonium chloride is added (the order of addition is: half of the total amount of 3-chloro-2-hydroxypropyltrimethylammonium chloride is added at the beginning of the reaction, and the remaining part is added after 2.5 h of reaction). The mass ratio of chitosan, 1-allyl-3-methylimidazolium chloride, and 3-chloro-2-hydroxypropyltrimethylammonium chloride is 1:25:7. The mixture is stirred for 5 h. After stirring, ethanol is added to precipitate the mixture. The amount of ethanol added is 3 times the total mass of the system. The mixture is allowed to stand and separate into layers, filtered, washed with acetone, and dried at 80°C for 5 h to obtain chitosan quaternary ammonium salt.

[0143] Step 2: Dissolve the chitosan quaternary ammonium salt in an appropriate amount of deionized water to obtain a chitosan quaternary ammonium salt solution, wherein the mass ratio of chitosan quaternary ammonium salt to deionized water is 1:50; add triethylamine to the chitosan quaternary ammonium salt solution to adjust the pH of the system to 8.5, then add 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate, wherein the mass ratio of chitosan quaternary ammonium salt, 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate is 1:0.05:1.2, and stir rapidly until fully dispersed. Then raise the system temperature to 80°C and stir for 5 hours; after the reaction is completed, cool to room temperature, precipitate with ethanol, filter, wash repeatedly with acetone, and dry at 60°C for 2 hours to obtain modified chitosan quaternary ammonium salt;

[0144] Step 3: Mix the modified chitosan quaternary ammonium salt and deionized water in a certain proportion to obtain a mixed solution with a concentration of 18 g / L; immerse the mulberry branch fibers in the mixed solution at an immersion temperature of 50°C for 2 hours at a liquor ratio of 1:30. After immersion, remove and roll the fibers using a two-dip, two-roll process with a roll residue of 80%. Then, place the fibers in a vacuum drying oven at 60°C for 3 hours to dry them under vacuum. The modification is then complete.

[0145] Comparative Example 1

[0146] The difference from Example 1 is that the mulberry branch fibers were not modified, while the remaining steps are the same as in Example 1.

[0147] Comparative Example 2

[0148] The difference from Example 1 is that the 3-chloro-2-hydroxypropyltrimethylammonium chloride is added entirely at the beginning of the reaction, and the remaining steps are the same as in Example 1.

[0149] Comparative Example 3

[0150] The difference from Example 1 is that the mass ratio of chitosan quaternary ammonium salt, 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate is 1:0.02:0.7, and the remaining steps are the same as in Example 1.

[0151] Comparative Example 4

[0152] The difference from Example 1 is that the mass ratio of chitosan quaternary ammonium salt, 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate is 1:0.02:1.3, and the remaining steps are the same as in Example 1.

[0153] Comparative Example 5

[0154] The difference from Example 1 is that 2,6-di-tert-butyl-p-cresol was not added, while the rest of the steps are the same as in Example 1.

[0155] Comparative Example 6

[0156] The difference from Example 1 is that glycidyl methacrylate was not added, while the rest of the steps are the same as in Example 1.

[0157] Comparative Example 7

[0158] The difference from Example 1 is that triethylamine was not added, but the rest of the steps are the same as in Example 1.

[0159] (i) The strength properties of the whole mulberry branches prepared in each embodiment and comparative example were tested using biodegradable nonwoven fabric. The test method was as follows: the electronic fabric strength tester of type YG(B)026D-500 was used according to the national standard test standard. The nonwoven fabric provided in each embodiment and comparative example was cut into samples with a length of 200mm and a width of 50mm, three pieces each in the radial and weft directions. The nonwoven fabric samples were stretched and the measurement results were recorded. The results are expressed as average values. The results are shown in Table 1.

[0160] Table 1

[0161]

[0162] As shown in Table 1, the tensile strength and elongation at break of the biodegradable nonwoven fabric made from whole mulberry branches after modification treatment are improved to a certain extent, indicating that the modification process has affected the internal structure of mulberry branch fibers, resulting in a significant improvement in the toughness of the nonwoven bag.

[0163] (ii) The abrasion resistance of the whole mulberry branches prepared in each embodiment and comparative example was tested using biodegradable nonwoven fabric. The abrasion resistance test method was as follows: according to the national standard test standard, a YG402C-13 fabric abrasion tester was used to cut three samples with a diameter of 35mm. The abrasive was 180mm sandpaper, and a pressure of 610g was applied. The measurement results were recorded and expressed as average values. The results are shown in Table 2.

[0164] Table 2

[0165]

[0166] As can be seen from Table 2, the wear resistance of the whole mulberry branch obtained by the present invention after modification is significantly improved by using biodegradable nonwoven fabric.

[0167] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing biodegradable nonwoven fabric from whole mulberry branches, characterized in that, Includes the following steps: (1) After removing impurities from the collected mulberry branches, cut and crush them to obtain the crushed material; (2) Soften the scrap material to obtain softened material; (3) Rinse the softened material repeatedly with clean water. After rinsing, dehydrate and dry the material in sequence to obtain the dried material. (4) The dried material is sequentially opened and combed to obtain mulberry branch fibers; (5) The mulberry branch fibers are modified, laid into a web, needled and reinforced, and heat-set in sequence to obtain biodegradable nonwoven fabric for the whole mulberry branch.

2. The method for preparing biodegradable nonwoven fabric from whole mulberry branches according to claim 1, characterized in that, The softening in step (2) is performed using bio-enzyme softening technology, wherein the bio-enzyme includes at least one of alkaline pectinase, laccase, and hemicellulase; Based on the dry weight of the mulberry branch fragments in step (1), the amount of alkaline pectinase is 120-300 IU / g, the amount of hemicellulase is 200-500 IU / g, and the amount of laccase is 300-500 IU / g; in the softening process in step (2), the alkaline pectinase solution, hemicellulase solution, or laccase solution are all prepared with buffer solution, the composition of which includes: NaH2PO4·2H2O of 0.8 mmol / L, CaCl2·2H2O of 5 mmol / L, MES of 2.5 mmol / L, and mannitol of 0.3 mmol / L; the softening treatment temperature in step (2) is 40℃-60℃, and the treatment time is 1h-2h.

3. The method for preparing biodegradable nonwoven fabric from whole mulberry branches according to claim 1, characterized in that, In step (3), the rinsing is carried out until the pH value of the material system is stable between 6.5 and 8.5; in step (3), the dehydration is carried out until the moisture content of the material is between 40% and 50%; in step (3), the drying temperature is 80℃ to 90℃, and the moisture content of the material after drying is maintained between 10% and 12%.

4. The method for preparing biodegradable nonwoven fabric from whole mulberry branches according to claim 1, characterized in that, The length of the mulberry branch fiber in step (4) is between 10mm and 30mm; the uniformity of the mulberry branch fiber in step (4) is not less than 90%.

5. The method for preparing biodegradable nonwoven fabric from whole mulberry branches according to claim 1, characterized in that, The needle density in step (5) is set to 80~200 needles / cm. 2 The needle puncture depth is 6mm~12mm, and the needle is punctured 3~5 times; the heat setting temperature in step (5) is 100℃~110℃.

6. The method for preparing biodegradable nonwoven fabric from whole mulberry branches according to claim 1, characterized in that, The modification process described in step (5) includes the following steps: Step 1: Mix chitosan and 1-allyl-3-methylimidazolium chloride to obtain a mixture; heat and stir the mixture in an oil bath at 75-85°C until the chitosan is fully dissolved; then add 3-chloro-2-hydroxypropyltrimethylammonium chloride under ultrasonic conditions, continue stirring for 3-5 hours, add ethanol to precipitate, allow to stand and separate into layers, filter, wash with acetone, and dry to obtain chitosan quaternary ammonium salt; Step 2: Dissolve the chitosan quaternary ammonium salt in an appropriate amount of deionized water to obtain a chitosan quaternary ammonium salt solution; add triethylamine to the chitosan quaternary ammonium salt solution to adjust the pH of the system to 8.0-8.5, then add 2,6-di-tert-butyl-p-cresol and glycidyl methacrylate, and stir rapidly until fully dispersed. Then raise the temperature of the system to 70-80℃ and stir for 3-5 hours; after the reaction is completed, cool to room temperature, precipitate with ethanol, filter, wash repeatedly with acetone, and dry to obtain modified chitosan quaternary ammonium salt; Step 3: Mix the modified chitosan quaternary ammonium salt and deionized water in a certain proportion to obtain a mixed solution; immerse the mulberry branch fibers in the mixed solution at a bath ratio of 1:20-30; after immersion, remove and roll the fibers, dry them, and the modification is complete.

7. The method for preparing biodegradable nonwoven fabric from whole mulberry branches according to claim 6, characterized in that, In step one, the mass ratio of chitosan, 1-allyl-3-methylimidazolium chloride, and 3-chloro-2-hydroxypropyltrimethylammonium chloride is 1:10-25:3-7; the amount of ethanol added is 2-3 times the total mass of the system; and the drying temperature is 60-80℃.

8. The method for preparing biodegradable nonwoven fabric from whole mulberry branches according to claim 6, characterized in that, In step two, the mass ratio of chitosan quaternary ammonium salt to deionized water is 1:20-50; the mass ratio of chitosan quaternary ammonium salt, 2,6-di-tert-butyl-p-cresol, and glycidyl methacrylate is 1:0.01-0.05:0.8-1.

2.

9. The method for preparing biodegradable nonwoven fabric from whole mulberry branches according to claim 6, characterized in that, Step 3: The concentration of the mixed solution is 10-18 g / L; the impregnation temperature is 50℃ and the impregnation time is 1-2 h; the rolling process specifically involves two dips and two rolls with a roll residue of 70-80%; the drying temperature is 60-70℃ and the drying time is 1-3 h.

10. The whole mulberry branch prepared by the method according to any one of claims 1-9 is used to make biodegradable nonwoven fabric.

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