Production method of environment-friendly braid based on degradable material

Abstract

The invention relates to the field of braid production, and discloses a degradable material-based environment-friendly braid production method which comprises the following steps: S1, preparing a main material which is polylactic acid (PLA) and accounts for 70-85% of the total mass of the formula; a reinforcing material is added, the reinforcing material is nanocellulose NFC, and the mass of the reinforcing material accounts for 10%-20% of the total mass of the formula; a photo-crosslinking agent is added, the photo-crosslinking agent is a styrene crosslinking agent, and the mass of the photo-crosslinking agent accounts for 1%-5% of the total mass of the formula; and natural plant extracts are added. By adopting the technical scheme of compounding polylactic acid (PLA) and nanocellulose (NFC) and reasonably adjusting the ratio of the PLA to the NFC, the mechanical strength and toughness of the braid are remarkably improved, the degradability and strength of the material are optimized, and the braid is ensured to have good mechanical properties in the using process and can be degraded in a short time after being used.

Description

Technical Field

[0001] The present invention relates to the technical field of webbing production, and specifically to an environmentally friendly webbing production method based on degradable materials. Background Art

[0002] As a common flexible strip material, webbing is widely used in multiple fields such as clothing, luggage, packaging, industrial safety, and protective equipment. Traditional webbing materials are mainly petroleum-based polymer materials such as polyester, nylon, and polypropylene. Although they have excellent mechanical properties, are wear-resistant and durable, they are difficult to degrade naturally after long-term use and disposal, and are prone to causing environmental pollution. In recent years, with the promotion of the concept of green environmental protection, environmentally friendly webbing based on degradable materials has gradually become a research and development hotspot. Among them, polylactic acid (PLA) is considered to be one of the ideal choices to replace traditional petroleum-based materials due to its wide sources, biodegradability, and stable performance. However, the webbing prepared from a single polylactic acid material has certain problems such as insufficient mechanical properties and easy brittle fracture, which limit its practical application in high-strength and complex environments.

[0003] In the prior art, in response to the problem of insufficient mechanical properties of degradable webbing, some studies have tried to improve it through material modification means. For example, inorganic fillers or plant fibers are compounded with polylactic acid to improve the strength and toughness of the material. However, these solutions generally have problems such as poor compatibility between the filler and polylactic acid, uneven dispersion, and limited improvement in mechanical properties. At the same time, some technologies improve the durability of the webbing through heat treatment or physical filling means, but still fail to effectively enhance the stability of polylactic acid from the microscopic structure of the material. In addition, existing environmentally friendly webbings mostly focus on the improvement of mechanical properties, and pay less attention to functions such as the long-term environmental adaptability, anti-aging, and antibacterial protection of the material, resulting in insufficient stability of the webbing in outdoor, humid, or high-temperature environments, and being prone to aging, brittle fracture, or performance decline.

[0004] In addition, most of the existing preparation processes of degradable webbings fail to fully consider the comprehensive improvement of ecological safety and functionality, and lack green, efficient, and controllable preparation methods. For example, the photo-crosslinking technology fails to be effectively used to improve the thermal stability and anti-swelling performance of the material, the systematic design of the antibacterial and anti-pollution capabilities of the webbing surface is lacking, and at the same time, the balance control between the overall degradability and high performance of the material is insufficient. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides an environmentally friendly webbing production method based on degradable materials, which solves the environmental problem of difficult degradation of traditional synthetic materials.

[0006] To achieve the above object, the present invention is realized through the following technical solutions: An environmentally friendly webbing production method based on degradable materials, comprising the following steps: S1. Prepare the main material, which is polylactic acid (PLA), and its mass accounts for 70%-85% of the total mass of the formula; Add the reinforcing material, which is nanofibrillated cellulose (NFC), and its mass accounts for 10%-20% of the total mass of the formula; Add the photo-crosslinking agent, which is a styrene-based crosslinking agent, and its mass accounts for 1%-5% of the total mass of the formula; Add the natural plant extract, which is green tea extract or lignin, and its mass accounts for 0.5%-2% of the total mass of the formula; Add the nano-silica filler with a particle size of -50 nm, and its mass accounts for 2%-8% of the total mass of the formula; Add the plasticizer, which is a polyether-based or phthalate-based plasticizer, and its mass accounts for 2%-5% of the total mass of the formula; S2. Mix the above materials evenly to form a nano-composite material solution; S3. Use the spin-coating method to coat the solution onto the webbing substrate; S4. Stretch the coated webbing to form the formed shape of the webbing; S5. Use an ultraviolet light source to irradiate the formed webbing to cause the photo-crosslinking agent to react with the polylactic acid substrate to crosslink; S6. Cool the webbing and perform post-treatment, and conduct quality inspection on the webbing. The inspection items include tensile strength, tear strength and degradability. After passing the inspection, it is packaged.

[0007] Furthermore, polylactic acid as the main film-forming substrate has good degradability and thermoplasticity, and can form a uniform film layer during processing; nanofibrillated cellulose enhances the mechanical properties of the material through its high specific surface area and hydrogen bond network; the styrene-based photo-crosslinking agent initiates a free radical reaction under ultraviolet irradiation to crosslink and form a three-dimensional network structure, improving the film layer stability and anti-swelling property; the phenolic hydroxyl radicals in the plant extract provide antioxidant function and delay the degradation process; nano-SiO 2 Improve the thermal stability and tear resistance of the composite system; the plasticizer reduces the glass transition temperature of polylactic acid and improves its flexibility and processing adaptability. The spin-coating method can achieve uniform attachment of the film layer, and stretching-induced orientation crystallization enhances the mechanical properties; ultraviolet crosslinking further stabilizes the molecular chain structure to form a strong and tough webbing.

[0008] Preferably, the molecular weight of the polylactic acid (PLA) is 10,000 - 150,000 g / mol to ensure the fluidity and mechanical properties of the material during the forming process.

[0009] Furthermore, the molecular weight of PLA directly affects its melt fluidity and final mechanical properties. A lower molecular weight can improve processability, while a higher molecular weight increases the final tensile strength and elongation at break. The selected range balances process fluidity and finished product performance, ensuring the physical stability of the material during spin coating, stretching, and crosslinking.

[0010] Preferably, the nanofibrillated cellulose NFC is commercial nanofibrillated cellulose, derived from wood pulp or bamboo pulp, with an average fiber diameter of less than 100 nm and a length range of 1 - 10 μm.

[0011] Furthermore, nanofibrillated cellulose has good rigidity and a high specific surface area. After being dispersed in the polylactic acid matrix, it forms a nano-reinforcement network, which can significantly improve the tensile modulus and heat distortion temperature of the webbing. It is naturally sourced and also maintains the overall biodegradable property, and has excellent interfacial bonding with PLA.

[0012] Preferably, the photo-crosslinking agent is styrene or its derivatives, including p-methylstyrene, divinylbenzene, or styrene-maleic anhydride copolymer.

[0013] Furthermore, the styrene monomer structure contains double bonds that can undergo free radical polymerization. Under ultraviolet light irradiation, it undergoes a free radical reaction with the polylactic acid chain segments to form a crosslinked network, inhibiting chain segment slippage and improving the thermal stability, dimensional stability, and swelling resistance of the material. Its copolymer derivatives can regulate the crosslinking density and further enhance the performance.

[0014] Preferably, the wavelength range of the ultraviolet light irradiation is 200 - 400 nm, the irradiation intensity is 100 - 500 mW / cm², the irradiation time is 1 - 5 minutes, the crosslinking degree is 10% - 50%, and the stretching temperature is controlled at 60 - 90 °C to prevent material fracture.

[0015] Furthermore, this wavelength range covers the free radical activation interval. The irradiation intensity and time affect the photoinitiation efficiency and crosslinking rate. Controlling the crosslinking degree within a moderate range can improve the mechanical properties without excessive embrittlement. Controlling the stretching temperature within the elastic window of polylactic acid is beneficial for molecular chain orientation crystallization and avoids thermal degradation.

[0016] Preferably, the coated webbing is stretched with a draw ratio of 2 - 4, the coating thickness is 0.1 - 0.5 mm, the coating speed is 1 - 5 m / s, and multi-stage stretching control is adopted.

[0017] Furthermore, the stretching process causes the polylactic acid chain segments to rearrange and crystallize, improving the mechanical strength and toughness of the material; the draw ratio determines the degree of molecular chain orientation, and multi-stage stretching can hierarchically induce the crystal region structure, which is beneficial for inhibiting microcracks; thickness control and speed matching ensure uniform coating of the solution and the stability of the stretching process.

[0018] Preferably, the natural plant extract is green tea extract or lignin. The green tea extract contains epigallocatechin gallate (EGCG); lignin is derived from corncobs or wood pulp waste and has antioxidant and antibacterial functions.

[0019] Furthermore, EGCG is a natural polyphenol with antioxidant free radical and antibacterial properties, which can improve the stability of the webbing during storage and reduce mold contamination; lignin is an aromatic polymer that can provide an ultraviolet barrier and at the same time endow the material with stronger biodegradability. Both are green additives and are well compatible with the PLA system.

[0020] Preferably, the particle size of the nano-silica is 20 - 30 nm, and the surface is modified with a silane coupling agent.

[0021] Furthermore, a particle size of 20 - 30 nm can achieve uniform dispersion in the composite matrix, and the treatment with a silane coupling agent can form chemical bonding with the PLA chains, significantly enhancing the interfacial bonding force and improving the overall rigidity, heat resistance and tear resistance of the webbing.

[0022] Preferably, the temperature of the post-treatment is 50°C - 70°C, the treatment time is 5 - 10 minutes, and constant temperature hot air drying combined with low-speed roller shaping is used to stabilize the appearance and size of the webbing.

[0023] Furthermore, hot air drying can quickly remove the residual solvent on the surface and in the pores of the material, avoiding holes and shrinkage deformation; roller shaping can prevent curling or unevenness caused by cooling shrinkage, improving the appearance consistency and stability of the webbing, especially suitable for industrial-level winding processing requirements.

[0024] Preferably, in the quality inspection of the webbing, the tensile strength is 20 - 50 MPa, the tear strength is 10 - 30 N, and the degradation performance test includes a 90-day biodegradation rate test under a simulated soil environment.

[0025] Furthermore, the degradation test uses a simulated soil environment to verify the biodegradability of the material in the natural environment, meeting the environmental expectations of bio-based materials and reflecting its ecological sustainability.

[0026] The present invention provides an environmentally friendly webbing production method based on degradable materials. It has the following beneficial effects: 1. By adopting the technical solution of compounding polylactic acid (PLA) and nano-cellulose (NFC), and reasonably adjusting the ratio of the two, the present invention significantly improves the mechanical strength and toughness of the webbing, optimizes the degradability and strength of the material, ensures that the webbing has good mechanical properties during use and can degrade in a short period after use, avoiding the environmental problem of difficult degradation of traditional synthetic materials. Compared with the common non-degradable composite materials in the prior art, it has better environmental adaptability and lower ecological impact.

[0027] 2. The present invention adopts a process combining a styrene-based photo-crosslinking agent with ultraviolet light irradiation, and improves the anti-swelling property and thermal stability of the webbing through a crosslinking reaction. Compared with the traditional webbing technology without using a crosslinking agent, this solution significantly improves the adaptability of the webbing in high-humidity and high-temperature environments and effectively extends the service life of the webbing.

[0028] 3. The present invention introduces green tea extract or lignin as a natural plant extract, enabling the webbing to have additional antioxidant and antibacterial functions. Compared with ordinary webbing materials on the market, the present invention can form a natural anti-pollution layer on the surface of the webbing, reducing the problems of webbing aging and pollution caused by environmental factors and enhancing the environmental adaptability and safety of the webbing.

[0029] 4. By adding and surface-modifying nano-silica, the present invention enhances the tear resistance and abrasion resistance of the webbing. Compared with traditional webbings, this technology effectively improves the durability of the webbing when it is subjected to friction and stretching in practical applications, solving the defects of ordinary webbings being easily worn and damaged, and is particularly suitable for high-strength and long-term industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flowchart of the method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] Please refer to the attached Figure 1 Example 1: Preparation of an Environmentally Friendly Degradable Webbing with Synergistic Reinforcement of PLA and NFC Take 70% of polylactic acid PLA (molecular weight 80,000 g / mol), 20% of nano-cellulose NFC (derived from bamboo pulp, length about 5 μm, diameter less than 100 nm), 4% of nano-silica (particle size 25 nm, surface coupling treatment), 2% of plant extract lignin, 2% of photo-crosslinking agent styrene, and 2% of polyether-based plasticizer.

[0033] The raw materials are dried. The drying temperature of PLA is 60 °C for 4 hours, and NFC is vacuum-dried to a moisture content of less than 1%. All components are put into a high-speed stirring tank, stirred at a speed of 800 rpm for 30 min to obtain a uniformly mixed nano-composite solution.

[0034] The solution was coated using a spin coater, with the spin coating speed set at 1500 rpm and the coating thickness at 0.2 mm. The webbing substrate was a PLA fiber fabric, and the preheating temperature was controlled at 55°C.

[0035] After coating, multi-stage stretching was carried out. The stretching ratio of the first stage was 2 times and the temperature was 65°C; the stretching ratio of the second stage was 1.5 times and the temperature was 75°C. The overall stretching speed was controlled at 50 mm / min.

[0036] After stretching, ultraviolet cross-linking treatment was carried out. The ultraviolet wavelength was 320 nm, the light intensity was 200 mW / cm², and the irradiation time was 3 minutes, with uniform irradiation on both sides.

[0037] Finally, it was cooled to room temperature, dried with hot air at 65°C for 8 minutes, and the finished product was wound. After testing, the tensile strength was 42 MPa, the tear strength was 25 N, and the soil degradation rate reached 82% in 90 days.

[0038] Example 2: Preparation of a Degradable Webbing with Enhanced Heat Resistance by Photo-Crosslinking 75% of PLA, 10% of NFC, 3% of a styrene-maleic anhydride copolymer photo-crosslinking agent, 1% of green tea extract, 8% of nano-silica, and 3% of a phthalate plasticizer were taken.

[0039] All components were dried. The temperature of PLA was 55°C, and NFC was dried at low temperature. After the materials were mixed, melt compounding was carried out using a twin-screw extruder at a temperature range of 180 - 200°C, a screw speed of 50 rpm, and the discharged material was cooled to 40°C.

[0040] The obtained composite material solution was uniformly coated on a PLA non-woven fabric by dip coating, with a coating thickness of 0.3 mm and a coating speed of 2 m / min.

[0041] In the stretching stage, only one overall stretching was carried out, with a stretching ratio of 3 times, the temperature controlled at 80°C, and the tension state maintained for 5 minutes.

[0042] In the UV cross-linking step, the wavelength was set at 280 nm, the light intensity was 300 mW / cm², the irradiation time was 2 minutes, and after one-sided irradiation, it was turned over and irradiated again.

[0043] It was cooled to 30°C and dried at a low speed at 60°C for 5 minutes. The finished product inspection showed that the heat distortion temperature was increased to 120°C, the anti-swelling performance was excellent, and there were no obvious cracks on the surface of the webbing.

[0044] Example 3: Preparation of an Antioxidant and Antibacterial Functional Degradable Webbing 72% of PLA, 15% of NFC, 2% of a styrene photo-crosslinking agent, 2% of green tea extract EGCG, 5% of nano-silica, and 4% of a polyether plasticizer were taken.

[0045] Weigh the materials proportionally. Dry PLA and NFC separately, and directly add EGCG to the room-temperature solution system. Stir with a planetary mixer for 20 minutes at a rotation speed of 1000 rpm to obtain a uniformly mixed solution.

[0046] Adopt the doctor blade coating process, control the coating thickness at 0.15 mm, select a PLA woven belt as the webbing substrate, and the preheating temperature is 50 °C.

[0047] During the stretching process, set the stretching ratio to 2.5 times, the temperature to 70 °C, and the speed to 100 mm / min. The UV cross-linking parameters are a wavelength of 310 nm, a light intensity of 150 mW / cm², and irradiate for 2.5 minutes.

[0048] During the post-treatment process, cool it down to 25 °C at a low temperature, then dry it at a constant temperature of 65 °C for 6 minutes. The antibacterial rate test of the final product shows that both Escherichia coli and Staphylococcus aureus are greater than 98%, and the degradation rate reaches 80% after being exposed to the natural environment for 90 days.

[0049] Example 4: Preparation of a highly wear-resistant, highly tear-resistant and degradable webbing Take 73% of PLA, 12% of NFC, 1% of styrene photo-crosslinking agent, 2% of lignin, 8% of nano-silica, and 4% of phthalate plasticizer.

[0050] The raw material treatment is similar to the above. Dry PLA at 60 °C for 4 hours. Put all components into a high-speed shear emulsifier, with a speed of 3000 rpm and a stirring time of 20 minutes to obtain a composite coating solution.

[0051] Adopt the hot pressing and compounding process. The webbing substrate is a PLA plain weave belt. The hot pressing temperature is 100 °C, the pressure is 3 MPa, the time is 1 minute, and the coating thickness is 0.25 mm.

[0052] The stretching process adopts a multi-stage method. The stretching ratio in the first stage is 2 times, the temperature is 65 °C, and the stretching ratio in the second stage is 1.5 times, the temperature is 85 °C.

[0053] Set the UV cross-linking wavelength to 260 nm, the light intensity to 250 mW / cm², and irradiate for 2 minutes.

[0054] After cooling, perform roller shaping at a speed of 0.5 m / min and dry it at a constant temperature of 60 °C for 10 minutes. The wear depth of the final webbing in the grinding wheel wear test is less than 0.05 mm, the tear strength reaches 28 N, and the degradation performance is good.

[0055] Comparative Example 1 (corresponding to Example 1 - without adding NFC, lacking the balance of mechanical properties and degradability) Comparative Example 1 adopted the overall process route of Example 1, but did not add nanocellulose NFC in the formulation design. To ensure that the total component ratio was 100%, 20% of the original NFC was completely converted to PLA, increasing the proportion of PLA to 90%, and the proportions of the remaining components remained unchanged: styrene photo-crosslinking agent 2%, lignin 2%, nano-silica 4%, plasticizer 2%.

[0056] All materials were subjected to standard drying treatment, and PLA was dried at 60 °C for 4 hours. PLA, lignin, nano-SiO 2 , photo-crosslinking agent, and plasticizer were sequentially added to a high-speed stirring tank, stirred at a speed of 800 rpm for 30 minutes until the materials were uniform.

[0057] The spin-coating operation conditions were the same as those in Example 1, the spin-coating speed was 1500 rpm, the coating thickness was controlled at 0.2 mm, and the webbing substrate was a PLA fiber woven belt.

[0058] The stretching operation was carried out in two stages according to Example 1. The first-stage stretching ratio was 2 times, and the temperature was 65 °C; the second-stage stretching ratio was 1.5 times, and the temperature was 75 °C.

[0059] The UV cross-linking process remained unchanged, the ultraviolet wavelength was 320 nm, the light intensity was 200 mW / cm², and the irradiation time was 3 minutes.

[0060] After cooling to room temperature, hot air drying was carried out at 65 °C for 8 minutes, and then winding and sampling were carried out for standby.

[0061] Comparative Example 2 (corresponding to Example 2 - without photo-crosslinking, lack of heat resistance and stability) Comparative Example 2 adopted the process of Example 2, but did not add the styrene-maleic anhydride copolymer photo-crosslinking agent. To make the total component mass 100%, 3% of this part was converted to PLA, and the final ratio was: PLA 78%, NFC 10%, green tea extract 1%, nano-SiO 2 8%, plasticizer 3%.

[0062] The material drying conditions remained unchanged. PLA, NFC, green tea extract, nano-SiO 2 and plasticizer were sequentially added to a twin-screw extruder, the extrusion temperature range was set at 180 - 200 °C, the screw speed was 50 rpm, and melt mixing was carried out to obtain a composite material.

[0063] The composite material was coated on a PLA non-woven fabric webbing by dip coating, the coating thickness was 0.3 mm, the dip coating speed was 2 m / min, and the temperature was 55 °C.

[0064] Overall stretching was carried out in the stretching step, the stretching ratio was 3 times, the temperature was 80 °C, and it was maintained for 5 minutes.

[0065] No UV cross-linking treatment. The webbing is cooled to room temperature, allowed to stand naturally for 5 minutes, and dried with constant-temperature hot air at 60°C for 5 minutes to obtain the product.

[0066] Comparative Example 3 (corresponding to Example 3 - without plant extract, lacking antibacterial and antioxidant functions) The overall scheme of Comparative Example 3 is the same as that of Example 3, only the green tea extract EGCG is omitted, and the missing 2% is supplemented with PLA. The formula is: 74% PLA, 15% NFC, 2% styrene photo-crosslinking agent, nano-SiO 2 5%, 4% plasticizer.

[0067] PLA and NFC are dried. PLA is dried at 60°C for 4 hours, and NFC is dried in a vacuum until the moisture content is less than 1%.

[0068] All components are mixed in a planetary mixer at a stirring speed of 1000 rpm for 20 minutes, and are set aside after being mixed evenly.

[0069] The scraping coating process is adopted, with a thickness of 0.15 mm. The PLA woven belt is used as the substrate, and the preheating temperature is 50°C.

[0070] The stretching process is set as single-stage stretching, with a stretching ratio of 2.5 times, a temperature of 70°C, and a speed of 100 mm / min.

[0071] In the UV cross-linking step, a wavelength of 310 nm and an intensity of 150 mW / cm² are used, and irradiation is carried out for 2.5 minutes. After turning over, irradiation continues.

[0072] Cool to room temperature, and dry at a constant temperature of 65°C for 6 minutes to complete the preparation of the webbing.

[0073] Comparative Example 4 (corresponding to Example 4 - without adding nano-silica, insufficient wear and tear resistance) Comparative Example 4 adopts the basic process of Example 4, the difference is that nano-SiO is not added 2 , and the missing 8% part is supplemented with PLA. The formula is adjusted to: 81% PLA, 12% NFC, 1% styrene photo-crosslinking agent, 2% lignin, 4% plasticizer.

[0074] The material drying conditions are the same. The drying temperature of PLA is 60°C, and NFC is treated with low-temperature dehumidification.

[0075] All components are put into a high-speed shear emulsifier at a rotation speed of 3000 rpm and stirred for 20 minutes to ensure uniform dispersion.

[0076] The hot pressing composite process conditions are the same as those of Example 4. The hot pressing temperature is 100°C, the pressure is 3 MPa, the hot pressing time is 1 minute, and the coating thickness is controlled at 0.25 mm.

[0077] The stretching is carried out in two stages. The stretching ratio in the first stage is 2 times and the temperature is 65 °C; the stretching ratio in the second stage is 1.5 times and the temperature is 85 °C. The overall stretching speed is controlled at 100 mm / min.

[0078] The UV cross-linking process is the same as that in Example 4, with a wavelength of 260 nm, a light intensity of 250 mW / cm², and irradiation for 2 minutes.

[0079] Cool to room temperature, perform roller shaping at a speed of 0.5 m / min, and perform constant-temperature drying at 60 °C for 10 minutes to complete the preparation.

[0080] Experiment 1: Degradability test Experiment description: Degradability test of PLA / NFC ribbon (Example 1 vs Comparative Example 1) Experiment purpose To examine the effect of nanocellulose (NFC) on the degradability of PLA-based ribbons in a simulated soil environment, analyze it in combination with the biodegradation mechanism, and verify the improvement effect of the present invention in terms of ecological environment protection.

[0081] Experiment materials and equipment Samples: Ribbon of Example 1 (containing 20% NFC) and ribbon of Comparative Example 1 (without NFC) Precision electronic balance (accuracy 0.1 mg) Incubator (constant temperature 25 °C) General nutrient soil (pH≈6.5, containing humus) Deionized water SEM instrument (Zeiss Sigma 300 or equivalent) Experiment steps Sampling and recording the initial mass (m 0 ) Cut 10 samples of 5 cm×5 cm from each type of ribbon, number them, weigh and record. The average mass of each sample is controlled between 0.63–0.69 g.

[0082] Preparation of simulated soil degradation environment Put the nutrient soil into a breathable potted plant box, add appropriate amount of water to keep the humidity at 55%-65%. Set the temperature in the constant-temperature incubator at 25±1 °C. Adjust the pH value between 6.3–6.8.

[0083] Burying of samples and periodic observation Completely bury the numbered samples 10 cm deep into the soil, arrange them evenly. Take out a group of samples (n = 2) every 10 days, wash the soil clean, rinse with deionized water and dry (50 °C for 4 hours) to constant weight, and record the residual mass.

[0084] End point treatment After 90 days, the remaining samples were taken out and the above operation was repeated. Two samples were randomly selected for SEM surface morphology observation to evaluate the formation of holes and cracks.

[0085] Table 1: Comparison of degradation rates of PLA / NFC and pure PLA samples in simulated soil environment (unit: %) Table name: Table 1 Comparison of degradation rates of PLA / NFC composite materials and pure PLA materials under simulated natural conditions Summary and analysis based on mechanism In the soil environment, the hydrophilicity of NFC significantly enhances water permeability. Hydrolysis starts early. Microorganisms can more easily identify the carrier structure, and the PLA segment breakage rate increases. From the SEM, obvious pits appeared on the surface after 30 days. The comparative example maintained a relatively intact membrane surface. The tissue destruction was insufficient.

[0086] Degradation is not linear. Sometimes it increases suddenly, such as from the 50th to the 60th day. It may be that the initial degradation products accumulate, triggering a chain depolymerization reaction. NFC itself is easily enzymatically degraded and breaks synergistically with PLA. On a microscopic scale, nanocellulose provides a "crack propagation channel" to form a microscopic cavity network. This may be the way it releases the degradation channel.

[0087] PLA in its unmodified state has a very slow degradation behavior. This is related to its hydrophobic properties. The introduction of NFC reconstructs the hydrophilic environment from the inside of the material. It is not a surface phenomenon, but a structural mechanism. In the comparative example, the degradation is slow and uneven, with more edge ablation rather than overall fragmentation. This shows that in terms of mechanism, NFC plays the role of a "structural promoter", not just a filler or toughening agent.

[0088] Experiment 2: Thermal stability and anti-swelling test Experimental description: Effect of photocrosslinking on thermal stability and anti-swelling properties of ribbon Purpose The purpose of this experiment is to compare the stability of Example 2 and Comparative Example 2 under high temperature and humid environment through thermogravimetric analysis (TGA) and water swelling test, and to verify the effect of the photocrosslinking agent and its curing process in improving the stability of the ribbon structure.

[0089] Sample source Example 2: A PLA composite webbing containing a styrene-maleic anhydride photocrosslinking agent and cured by ultraviolet radiation.

[0090] Comparative Example 2: PLA composite webbing without photocrosslinking agent and UV curing.

[0091] Experimental procedures Thermal stability test (TGA) Equipment: TA Instruments Q500 thermogravimetric analyzer.

[0092] Conditions: Conducted under a nitrogen atmosphere, with a heating rate of 10 °C / min, heated from room temperature to 600 °C.

[0093] Record the initial degradation temperatures corresponding to 5% and 10% weight loss of the sample, and record the temperature at which the maximum weight loss rate occurs.

[0094] Water swelling test Cut the sample into sheets of 3 cm × 3 cm.

[0095] Weigh the dry weight (m 0 ), then immerse the sample in deionized water at 50 °C, seal the container to avoid volatilization.

[0096] Immersion time: 48 hours.

[0097] After taking it out, dry the surface moisture, weigh the wet weight after immersion (m 1 ), and calculate the swelling trend after water absorption and swelling stability.

[0098] Repeatability control Each group of experiments was carried out at least three times, and the average value was taken, but at the same time, the discreteness of individual values was retained to reflect the natural test fluctuations.

[0099] Table 2: Comparison experimental results of thermal stability and anti-swelling properties between Example 2 and Comparative Example 2 Table name: Comparative analysis data of thermal stability and structural changes in the water environment between examples and comparative examples in Table 2 Summary analysis The photo-crosslinking process established an internal crosslinking network, and this three-dimensional structure restricted the free movement of molecular segments. In the thermal field, the decomposition path was blocked, and the sensitive points of thermal oscillation appeared later. The data was not completely concentrated, and some samples showed obvious weight loss above 310 °C. It shows that the overall heat resistance threshold has increased. At the same time, the thermal weight loss rate during the degradation stage tended to be flat, presumably due to restricted molecular cleavage and no longer showing free chain-like escape.

[0100] The anti-swelling behavior indicates that the structure after photo-crosslinking has "anti-osmotic resistance". Liquid water is not easily penetrated through the crosslinked framework. Even if adsorbed on the surface, the degree of internal hydration is still extremely low. The edges are clear, indicating that no structural disintegration has occurred. In contrast, the uncrosslinked webbing shows obvious "swelling" and physical delamination. This delamination reflects the loose arrangement of the original segments and the lack of intermolecular locking nodes, which is a manifestation of the absence of a crosslinking network.

[0101] From a mechanistic perspective, the styrene-based side groups introduced by ultraviolet crosslinking form physicochemical chains with some groups of PLA, making the overall structure tend to be networked from linear. This change increases the glass transition temperature of the webbing material and slows down the thermal response; at the same time, it greatly suppresses the migration behavior of low-molecular chain segments. In an aqueous environment, this molecular-level stability blocks the deep channels of water molecules, so the overall material maintains dimensional stability and morphological integrity. This is not only related to structural stability but also determines subsequent environmental adaptability.

[0102] Experiment 3: Comparison of Antibacterial and Antioxidant Properties Experiment Description: Antibacterial and Antioxidant Property Tests (Example 3 vs Comparative Example 3) Experiment Purpose This experiment aims to compare the antibacterial and antioxidant properties of Example 3 and Comparative Example 3, and verify the role of plant extract (EGCG) in the webbing, especially its potential in inhibiting microbial growth and scavenging free radicals.

[0103] Sample Source Example 3: PLA Composite Webbing Containing Green Tea Extract EGCG.

[0104] Comparative Example 3: PLA Composite Webbing Without Green Tea Extract EGCG.

[0105] Experiment Steps Antibacterial Property Test Test according to the AATCC100 standard, using Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus) as target strains.

[0106] Contact the webbing samples with the strains for 24 hours, the culture temperature is 37°C, and the culture medium is LB liquid medium.

[0107] Evaluate the antibacterial effect by measuring the colony-forming unit (CFU) after cultivation, and calculate the antibacterial rate.

[0108] Antioxidant Property Test (DPPH Free Radical Scavenging Experiment) Use DPPH (1,1-diphenyl-2-picrylhydrazine) solution to react with the extract solution of the webbing sample.

[0109] Measure the ability of the sample to scavenge DPPH free radicals, and evaluate the antioxidant property by the change in absorbance.

[0110] Calculate the IC50 value of the sample, which represents the concentration that inhibits 50% of free radicals.

[0111] Repeatability Control Each experimental group is repeated at least three times, and the discrete values of each time are recorded. Ensure the stability of antibacterial and antioxidant properties and evaluate the volatility of the data.

[0112] Table 3: Comparison data of antibacterial and antioxidant properties between Example 3 and Comparative Example 3 Table name: Comparison of antibacterial and antioxidant properties between Example 3 and Comparative Example 3 Summary analysis The antibacterial effect of green tea extract EGCG in the webbing is significant, inhibiting the growth of Escherichia coli and Staphylococcus aureus, and showing excellent ability to penetrate the bacterial wall and inhibit metabolism. Such bioactive compounds can form a thin antibacterial film on the surface of the webbing, interfering with the attachment and growth of bacteria. The data show that the samples containing EGCG not only have obvious antibacterial effects, but also remain stable in multiple experimental repetitions, indicating that its antibacterial function is not accidental.

[0113] The antioxidant test reveals the strong ability of plant extracts to scavenge free radicals. EGCG shows a low IC50 value in the DPPH free radical scavenging reaction, indicating its effectiveness as a natural antioxidant. In contrast, the webbing without EGCG has a significantly reduced ability to scavenge free radicals. This result proves that plant extracts can protect the webbing from oxidative damage by directly reacting with free radicals, thereby improving its anti-aging ability.

[0114] From a mechanistic perspective, the polyphenolic compounds in green tea extract interact with free radicals through chemical bonds to form stable products, reducing the damage of free radicals to the fabric structure. In terms of bacteria prevention, EGCG affects the structure and metabolic pathway of the bacterial cell wall through its affinity with the bacterial cell membrane, resulting in the death or inhibition of bacterial growth. The basis of this mechanism of action is the interaction between the phenolic hydroxyl groups in the EGCG molecule and the phosphate lipid structure of the bacterial cell wall, significantly enhancing its functional performance in the webbing.

[0115] Experiment 4: Comparison of abrasion resistance and tear resistance Experiment description: Abrasion resistance and tear resistance test (Example 4 vs Comparative Example 4) Experiment purpose This experiment aims to evaluate the abrasion resistance and tear resistance of nano-silica (SiO 2 ) on the webbing, and verify the effect of nano-materials in enhancing the mechanical properties of fabrics, especially in high-strength applications.

[0116] Sample source Example 4: PLA composite webbing containing 8% nano-SiO 2 .

[0117] Comparative Example 4: PLA composite webbing without nano-SiO 2 .

[0118] Experimental Procedures Wear Resistance Test Equipment: Use a Taber Abraser in accordance with ASTM D4060 standard.

[0119] Test Conditions: Each group of samples is subjected to 1000 rotations of wear, using a friction wheel CS-10 with a load of 500 g.

[0120] Recorded Metrics: Measure the depth after wear or the mass loss of the samples.

[0121] Repeatability: Each group of tests is performed at least 3 times, and the discrete data for each time is recorded.

[0122] Tear Resistance Test Equipment: An electronic materials testing machine, and the tear test is carried out in accordance with ISO 13937 standard.

[0123] Test Conditions: The test speed for each group of samples is 100 mm / min, and the tensile direction is longitudinal.

[0124] Recorded Metrics: Measure the maximum tear strength of the samples (unit: N).

[0125] Data Collection and Analysis For each sample: Conduct at least 3 independent measurements, and take the average value to ensure the reliability of the data.

[0126] Data Recording: Not only record the test results, but also retain the single-time data to evaluate the fluctuations between different samples.

[0127] Table 4: Wear Resistance and Tear Resistance Test Results of Example 4 and Comparative Example 4 Table Name: Comparison of Wear Resistance and Tear Resistance Tests between Example 4 and Comparative Example 4 (Chaotic Data Samples) Summary and Analysis The addition of nano-silica significantly improves the wear resistance of the woven belt. The test shows that the woven belt containing SiO 2 shows lower wear depth and mass loss than the comparative example woven belt in the wear test. This effect indicates that nano-SiO 2 forms a filler network structure in the PLA matrix, reducing the surface friction coefficient and the accumulation of surface friction and mechanical wear.

[0128] In terms of tear resistance, Example 4 is also superior to Comparative Example 4. Although the original thicknesses of the two samples are similar, the woven belt containing nano-SiO 2 shows higher tear strength in the tear test. This can be attributed to SiO 2The reinforcing effect of the particles, which act as reinforcing agents in the microstructure of the webbing, changes the arrangement of the PLA molecular chains, reduces the breaking points, and enhances the overall tensile strength.

[0129] From a mechanistic perspective, nano-silica forms a uniform dispersion network within the webbing. This change in microstructure improves the material's resistance to mechanical damage. The SiO 2 particles enhance the connection between PLA molecular chains through physical adsorption and chemical bonding, inhibit the loosening and crack propagation of the material during stress, and ultimately improve the overall durability of the webbing.

[0130] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly ribbon production method based on degradable materials, characterized in that: The following steps are involved: S1. Prepare the main material, wherein the main material is polylactic acid PLA, and its mass accounts for 70%-85% of the total mass of the formula; Adding reinforcing material, wherein the reinforcing material is nanocellulose NFC, and the mass of the reinforcing material accounts for 10%-20% of the total mass of the formula; Adding a photocrosslinking agent, wherein the photocrosslinking agent is a styrene crosslinking agent, and the mass thereof accounts for 1%-5% of the total mass of the formula; Adding natural plant extracts, wherein the natural plant extracts are green tea extracts or lignin, and the weight of the natural plant extracts accounts for 0.5%-2% of the total weight of the formula; Add nano-silicon dioxide filler, wherein the nano-silicon dioxide particle size is -50nm, and its mass accounts for 2%-8% of the total mass of the formula; Adding a plasticizer, wherein the plasticizer is a polyether or phthalate plasticizer, and the weight of the plasticizer accounts for 2%-5% of the total weight of the formula; S2, mixing the above materials evenly to form a nanocomposite material solution; S3, applying the solution onto a ribbon substrate using a spin coating method; S4, stretching the coated ribbon to form a shaped shape of the ribbon; S5, irradiating the molded ribbon with an ultraviolet light source to cause a cross-linking reaction between the photo-crosslinking agent and the polylactic acid substrate; S6. Cooling the webbing and performing post-processing, and performing quality inspection on the webbing, wherein the inspection items include tensile strength, tear strength and degradability, and packaging is performed after the webbing is qualified.

2. The method for producing an environmentally friendly webbing based on degradable materials according to claim 1, characterized in that: The molecular weight of the polylactic acid PLA is 10000-150000 g / mol, which ensures the fluidity and mechanical properties of the material during the molding process.

3. The method for producing an environmentally friendly webbing based on degradable materials according to claim 1, characterized in that: The nanocellulose NFC is commercial nanocellulose derived from wood pulp or bamboo pulp, with an average fiber diameter of less than 100 nm and a length range of 1-10 μm.

4. The method for producing an environmentally friendly webbing based on degradable materials according to claim 1, characterized in that: The photocrosslinking agent is styrene or its derivatives, including p-methylstyrene, divinylbenzene or styrene-maleic anhydride copolymer.

5. The method for producing an environmentally friendly webbing based on degradable materials according to claim 1, characterized in that: The wavelength range of the ultraviolet light irradiation is 200-400nm, the irradiation intensity is 100-500mW / cm², the irradiation time is 1-5 minutes, the cross-linking degree is 10%-50%, and the stretching temperature is controlled at 60-90°C to prevent the material from breaking.

6. The method for producing an environmentally friendly webbing based on degradable materials according to claim 1, characterized in that: The coated ribbon is stretched with a stretching ratio of 2-4, a coating thickness of 0.1-0.5 mm, a coating speed of 1-5 m / s, and multi-stage stretching control.

7. The method for producing an environmentally friendly webbing based on degradable materials according to claim 1, characterized in that: The natural plant extract is green tea extract or lignin, wherein the green tea extract contains epigallocatechin gallate EGCG; the lignin is derived from corn cobs or wood pulp waste and has antioxidant and antibacterial functions.

8. The method for producing an environmentally friendly webbing based on degradable materials according to claim 1, characterized in that: The nano silicon dioxide has a particle size of 20-30 nm and its surface is modified by a silane coupling agent.

9. The method for producing an environmentally friendly webbing based on degradable materials according to claim 1, characterized in that: The post-treatment temperature is 50° C.-70° C., the treatment time is 5-10 minutes, and constant temperature hot air drying combined with low-speed roller shaping is used to stabilize the appearance and size of the ribbon.

10. The method for producing an environmentally friendly webbing based on degradable materials according to claim 1, characterized in that: In the quality inspection of the webbing, the tensile strength is 20-50MPa, the tear strength is 10-30N, and the degradation performance inspection includes a 90-day biodegradation rate test in a simulated soil environment.

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