Controllable induction period of oxidative-biodegradable drip irrigation tape material and preparation method thereof

Abstract

This invention discloses a controllable induction period oxidative-biodegradable drip irrigation tape material and its preparation method, belonging to the field of environmentally friendly polymer materials technology. The material comprises, by weight percentage: 65%-85% matrix resin, 12%-18% thermoplastic starch, 0.4%-0.6% coated iron stearate and manganese stearate composite oxidant, 0.3%-0.5% ethyl cellulose-coated antioxidant microcapsules, 3%-5% maleic anhydride-grafted polyethylene, and 5%-8% nano-calcium carbonate. This invention, through antioxidant microencapsulation and slow-release technology and oxidant coating technology, precisely controls the fluctuation range of the induction period from ±6 months in existing technologies to ±1 month. The tensile strength retention rate is greater than 80% during the service life, the degradation rate in soil after 2 years is not less than 90%, and the microplastic residue is less than 5%. This invention solves the environmental pollution problem of traditional polyethylene drip irrigation tape and the technical bottleneck of unstable induction period control in existing dual-degradable materials. The raw material cost is only 1 / 2 to 1 / 3 of that of pure biodegradable materials, making it suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of environmentally friendly polymer materials technology, specifically to an oxidative-biodegradable drip irrigation tape material with a controllable induction period and its preparation method. Background Technology

[0002] Drip irrigation technology is a core measure for water conservation in arid and semi-arid regions. In Xinjiang, drip irrigation coverage in cotton fields has reached over 95%, with annual drip tape usage exceeding 1 billion meters. Traditional polyethylene drip tape is widely used in agricultural water-saving irrigation due to its excellent mechanical properties, chemical resistance, and low cost. However, polyethylene material has extremely strong chemical stability and is difficult to degrade in the natural environment. These discarded drip tapes can remain in the soil for hundreds of years, causing soil pollution, hindering mechanical operations, and posing a microplastic risk. Northwest China, including Xinjiang and Gansu, are major users of drip tape, generating over 500,000 tons of discarded tape annually. The recycling rate of traditional polyethylene drip tape is less than 30%, leaving a large amount in farmland, which has become a significant problem restricting sustainable agricultural development. Therefore, developing and using drip tape materials with stable performance and controllable degradation after disposal is of great practical significance.

[0003] Currently, the main technical approaches to solving the problem of drip irrigation tape pollution include pure biodegradable materials and oxidative-biodegradation dual degradation technology. Among them, pure biodegradable materials such as polylactic acid and poly(butylene adipate / terephthalate) can be completely degraded under specific conditions, but they have defects such as insufficient mechanical properties, poor water resistance, high cost and poor processing performance, making it difficult to meet the actual needs of field drip irrigation.

[0004] Oxidation-biodegradation technology, which introduces pro-oxidants into polyethylene to achieve controllable degradation after the service life, is an effective way to solve the above problems. However, existing technologies still have many technical defects: First, it is difficult to accurately control the induction period. The ratio of pro-oxidants to antioxidants mainly depends on experience. Antioxidants are added directly in powder form, resulting in partial consumption in the early stage of use. The induction period fluctuates within ±6 months, which cannot meet the requirement of a 2-year service life for drip irrigation tapes. Second, there is a contradiction between degradation rate and microplastic control. Existing technologies lack effective means to control the molecular weight distribution of degradation intermediates. Degradation that is too fast can easily lead to microplastic pollution, while degradation that is too slow loses its environmental friendliness. Third, the biodegradable components have poor compatibility with the polyethylene matrix. When thermoplastic starch is directly blended with polyethylene, the interfacial adhesion is weak. When the thermoplastic starch content exceeds 10%, the tensile strength of the composite material decreases by more than 30%, which cannot meet the strength requirements of drip irrigation tapes. Fourth, pro-oxidants have problems with uneven dispersion and migration. Stearate-based pro-oxidants are prone to agglomerate in the polyethylene matrix to form local high-concentration areas and migrate to the material surface during processing and use, resulting in uneven degradation.

[0005] Therefore, in view of the above situation, there is an urgent need to develop oxidative-biodegradable drip irrigation tape materials with controllable induction period and their preparation methods to overcome the shortcomings in current practical applications. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an oxidative-biodegradable drip irrigation tape material with a controllable induction period and its preparation method, so as to overcome the technical defects of the prior art, such as unstable induction period control, poor compatibility between biodegradable components and polyethylene matrix, and uneven dispersion of oxidizing agents, and to achieve precise control of the induction period and complete biodegradation of the material.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The controllable induction period oxidation-biodegradable drip irrigation tape material comprises, by weight percentage: 65%-85% matrix resin, 12%-18% thermoplastic starch, 0.4%-0.6% coated iron stearate and manganese stearate composite pro-oxidant, 0.3%-0.5% ethyl cellulose-coated antioxidant microcapsules, 3%-5% maleic anhydride-grafted polyethylene, and 5%-8% nano-calcium carbonate; the matrix resin is a mixture of low-density polyethylene and linear low-density polyethylene in a mass ratio of (1.5-2.5):1; the ethyl cellulose-coated antioxidant microcapsules have a coating rate of 30%-40% and a release half-life of 18-24 months under water extraction conditions at 37°C.

[0009] Preferably, the melt flow index of the low-density polyethylene is 2.0-3.0 g / 10 min, and the melt flow index of the linear low-density polyethylene is 1.5-2.5 g / 10 min.

[0010] Preferably, the grafting rate of the maleic anhydride-grafted polyethylene is 1.0%-1.5%; the nano-calcium carbonate is surface-treated with an aluminate coupling agent or stearic acid.

[0011] Preferably, the thermoplastic starch is prepared by mixing starch and glycerol in a mass ratio of (6.5-7.5):(2.5-3.5), and the starch has an amylose content of 20%-30%.

[0012] Preferably, the mass ratio of ferric stearate to manganese stearate in the coated ferric stearate and manganese stearate composite oxidant is (1.5-2.5):1, the coating layer is stearic acid, and the amount of stearic acid is 10%-15% of the total mass of the oxidant.

[0013] Preferably, the core material of the ethyl cellulose-coated antioxidant microcapsules is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of (1.5-2.5):1; the particle size of the microcapsules is 50-150 μm.

[0014] A method for preparing the above-described oxidative-biodegradable drip irrigation tape material with a controllable induction period includes the following steps:

[0015] S1: Prepare a coated iron stearate and manganese stearate composite oxidant by one of the following methods: melt coating, solvent coating or mechanical coating.

[0016] S2: The preparation of antioxidant microcapsules coated with ethyl cellulose by solvent evaporation method includes: dissolving antioxidant 1010, antioxidant 168 and ethyl cellulose in dichloromethane to prepare an oil phase; adding the oil phase to a polyvinyl alcohol aqueous solution and emulsifying it at high speed of 5000-8000 rpm for 5-10 min to form an oil-in-water emulsion; removing the solvent by vacuum evaporation; and then filtering, washing and drying.

[0017] S3: Preparation of thermoplastic starch, specifically including: mixing starch and glycerol at a mass ratio of (6.5-7.5):(2.5-3.5) and then plasticizing and granulating by twin-screw extrusion;

[0018] S4: After premixing the matrix resin, thermoplastic starch, maleic anhydride-grafted polyethylene and nano calcium carbonate for 3-5 minutes, add the coated iron stearate and manganese stearate composite oxidant and ethyl cellulose-coated antioxidant microcapsules and continue mixing for 2-3 minutes to obtain the premix.

[0019] S5: The premixed material is added to a twin-screw extruder for melt blending, extrusion, and granulation. The extrusion temperature is 160-200℃, the screw speed is 200-300rpm, the homogenization section is equipped with a vacuum devouring device, the vacuum degree is -0.06~-0.09MPa, and the length-to-diameter ratio of the twin-screw extruder is 40:1-48:1 to obtain composite material particles.

[0020] S6: Extruding composite material particles into drip irrigation tape products.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] The present invention provides an oxidative-biodegradable drip irrigation tape material with a controllable induction period and its preparation method. Through antioxidant microencapsulation slow-release technology and pro-oxidant encapsulation technology, the induction period is precisely controlled, reducing the fluctuation range of the induction period from ±6 months in the prior art to ±1 month. This ensures that the tensile strength retention rate of the material is greater than 80% during the 24-month service period, and the degradation rate in the soil after 2 years of use is not less than 90%. This solves the environmental pollution problem of traditional polyethylene drip irrigation tape and the technical bottleneck of unstable induction period control of existing dual-degradable materials.

[0023] This invention utilizes a blend system of low-density polyethylene and linear low-density polyethylene, maleic anhydride-grafted polyethylene for compatibilization modification, and nano-calcium carbonate reinforcement technology to increase the amount of thermoplastic starch to 12%-18% while ensuring the mechanical properties of the material. The tensile strength of the material can reach 15-17 MPa, and the elongation at break can reach 250-350%, which fully meets the industry standard requirements of 14 MPa tensile strength and 200% elongation at break for drip irrigation tape. At the same time, the raw material cost is only 10,000-12,000 yuan / ton, which is 1 / 3 of polylactic acid and 1 / 2 of poly(butylene adipate / terephthalate), showing a significant cost advantage.

[0024] This invention utilizes the synergistic catalysis of a composite pro-oxidant system of ferric stearate and manganese stearate to stably control the number-average molecular weight of degradation products within the range of 1000-2000 g / mol, which is within the range that microorganisms can efficiently assimilate. The molecular weight distribution is narrowed to a molecular weight distribution index of less than 3, and the residual amount of microplastics is less than 5%, which is significantly lower than the 10%-20% of the prior art, thus achieving complete biodegradation of the material.

[0025] Furthermore, antioxidant microencapsulation reduces the antioxidant loss rate during processing from 30%-40% to 5%-10%, and the rupture of the microcapsule wall increases the porosity of the material, thereby increasing the oxidative degradation rate after the induction period by 20%-30%. Through compatibilization modification and process optimization, thermoplastic starch forms a uniform island structure in the polyethylene matrix, resulting in a toughening effect. When the thermoplastic starch content is 15% and the phase domain size is 5-8 μm, the elongation at break of the composite material is 20%-30% higher than that of pure polyethylene. Nano-calcium carbonate not only plays a role in rigidity reinforcement, but also improves the dispersibility of thermoplastic starch and prooxidants through surface hydrogen bonding. At the same time, its rough surface increases the biomass of microorganisms on the material surface by 40%-60%, significantly promoting biodegradation.

[0026] The drip irrigation tape material of this invention has excellent processing performance, with a melt flow rate comparable to polyethylene, an extrusion speed of 40-50 m / min, and a product qualification rate of over 95%. It can be produced directly using existing polyethylene drip irrigation tape production equipment without additional equipment investment, and has good prospects for industrialization and promotion. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating the process for preparing antioxidant microcapsules in an embodiment of the present invention.

[0028] Figure 2 This is a scanning electron microscope image of antioxidant microcapsules in an embodiment of the present invention.

[0029] Figure 3 This is a release curve of antioxidant microcapsules in an embodiment of the present invention.

[0030] Figure 4 This is a flowchart illustrating the process of preparing thermoplastic starch in an embodiment of the present invention.

[0031] Figure 5 This is a flowchart illustrating the process of preparing drip irrigation tape materials in an embodiment of the present invention.

[0032] Figure 6 This is a schematic diagram of the island structure of the drip irrigation tape material in an embodiment of the present invention.

[0033] Figure 7 This is a scanning electron microscope image of the cross-section of the drip irrigation tape material in an embodiment of the present invention.

[0034] Figure 8 This is a transmission electron microscope image of the drip irrigation tape material in an embodiment of the present invention.

[0035] Figure 9 This is a thermogravimetric analysis (TGA) curve of the drip irrigation tape material in an embodiment of the present invention.

[0036] Figure 10 This is a differential scanning calorimetry (DSC) curve of the drip irrigation tape material in an embodiment of the present invention.

[0037] Figure 11 This is a Fourier transform infrared (FTIR) spectrum of the drip irrigation tape material in an embodiment of the present invention.

[0038] Figure 12 This is a graph showing the change in tensile strength of the drip irrigation tape material over time in an embodiment of the present invention.

[0039] Figure 13 This is a soil degradation curve of the drip irrigation tape material in an embodiment of the present invention.

[0040] Figure 14 This is a graph showing the CO2 release rate of the drip irrigation tape material in an embodiment of the present invention.

[0041] Figure 15 This is a molecular weight distribution diagram of the drip irrigation tape material after degradation in an embodiment of the present invention.

[0042] Figure 16 This is a scanning electron microscope image of microbial adhesion on the surface of the drip irrigation tape material in an embodiment of the present invention.

[0043] Figure 17 This is a schematic diagram of the single-wing labyrinth drip irrigation tape product structure in an embodiment of the present invention.

[0044] In the diagram: 1-PE matrix continuous phase, 2-TPS dispersed phase particles, 3-interfacial compatibilization zone, 4-PE matrix phase, 5-TPS island phase, 6-nano-calcium carbonate particles, 7-antioxidant microcapsules, 8-ethyl cellulose wall material, 9-pro-oxidant particles, 10-matrix surface, 11-microbial colony, 12-biofilm, 13-single wing, 14-maze channel, 15-outlet, 16-drip irrigation tape tube. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0046] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0047] like Figure 6 As shown, the drip irrigation tape material of the present invention has thermoplastic starch dispersed phase particles 2 uniformly distributed in the continuous phase 1 of polyethylene matrix, and the two are connected by maleic anhydride grafted polyethylene to form an interface compatibilization zone 3, which constitutes a typical island structure.

[0048] like Figure 7 As shown, cross-sectional scanning electron microscopy reveals that the interface between the polyethylene matrix phase 4 and the thermoplastic starch island phase 5 is tightly bonded, and the nano-calcium carbonate particles 6 are uniformly dispersed in the two phases.

[0049] like Figure 8 As shown in the transmission electron microscope image, the antioxidant microcapsules 7 coated with ethyl cellulose are dispersed in the matrix, the ethyl cellulose wall material 8 has a uniform thickness, and the composite pro-oxidant particles 9 of coated iron stearate and manganese stearate are distributed in the gaps between the microcapsules.

[0050] like Figure 16 As shown, after being buried in the soil, the surface 10 of the material matrix is ​​covered with a large number of microbial colonies 11, forming a dense biofilm 12, which significantly promotes biodegradation.

[0051] like Figure 17 As shown, the single-wing labyrinth drip irrigation tape product of the present invention includes a single wing 13, a labyrinth channel 14, an outlet 15, and a drip irrigation tape tube body 16; the labyrinth channel 14 is disposed on the inner side of the single wing 13 and communicates with the outlet 15; the drip irrigation tape tube body 16 is a flat strip tube body, which is extruded from the oxidized-biodegradable composite material of the present invention.

[0052] I. Material Composition and Functions of Each Component

[0053] The controllable induction period oxidation-biodegradable drip irrigation tape material of the present invention is composed of the following components by weight percentage: 45%-55% low-density polyethylene, 20%-30% linear low-density polyethylene, 12%-18% thermoplastic starch, 0.4%-0.6% coated iron stearate and manganese stearate composite pro-oxidant, 0.3%-0.5% ethyl cellulose coated antioxidant microcapsules, 3%-5% maleic anhydride grafted polyethylene, and 5%-8% nano calcium carbonate.

[0054] 1.1 Matrix Resin System

[0055] The matrix resin is a blend of low-density polyethylene and linear low-density polyethylene, wherein the melt flow index of low-density polyethylene is 2.0-3.0 g / 10 min (test conditions: 190℃, 2.16 kg), the melt flow index of linear low-density polyethylene is 1.5-2.5 g / 10 min, and the mass ratio of low-density polyethylene to linear low-density polyethylene is (1.5-2.5):1, preferably 2:1.

[0056] Low-density polyethylene (LDPE) has a high degree of molecular chain branching and a crystallinity of 40%-50%, exhibiting excellent flexibility and processing fluidity, making it suitable for extrusion molding of drip irrigation tape. It also facilitates the diffusion and degradation reaction of the coated iron stearate and manganese stearate composite oxidant particles 9, forming a continuous polyethylene matrix phase 1. Linear LDPE has a linear molecular chain structure containing a small amount of short branches, resulting in higher tensile strength and puncture resistance. Blending these two materials creates a synergistic effect; at a mass ratio of 2:1, the tensile strength of the material can reach 16-18 MPa, and the elongation at break is greater than 300%, fully meeting the usage requirements of the drip irrigation tape tube body 16.

[0057] When the amount of low-density polyethylene is less than 45%, the material cost increases; when it is more than 55%, the amount of thermoplastic starch dispersed phase particles 2 added is limited, and the degradation performance decreases. When the amount of linear low-density polyethylene is less than 20%, the toughening effect is not obvious; when it is more than 30%, the material rigidity decreases, and the drip irrigation tape tube 16 is prone to deformation.

[0058] 1.2 Biodegradable carrier—thermoplastic starch

[0059] Thermoplastic starch is prepared by mixing corn starch or cassava starch with glycerol in a mass ratio of (6.5-7.5):(2.5-3.5), preferably 7:3, wherein the amount of glycerol is 25%-30% of the starch mass, and the amylose content of the starch is 20%-30%.

[0060] As a hydrophilic biodegradable component, thermoplastic starch can be directly decomposed by microbial colonies 11 in soil, producing a porous structure, increasing the specific surface area of ​​the material matrix 10, and promoting subsequent degradation. At the same time, it exists in the polyethylene matrix phase 4 in the form of thermoplastic starch dispersed phase particles 2, forming an island structure. That is, the polyethylene matrix continuous phase 1 is a sea and the thermoplastic starch island phase 5 is an island. The phase domain size is controlled at 5-10 μm, which is beneficial to stress transfer and degradation control.

[0061] When the content of thermoplastic starch is below 12%, the biodegradation effect is not obvious, and the degradation rate in soil after 2 years is difficult to reach 90%. When it is above 18%, the dispersed phase particles of thermoplastic starch are difficult to disperse, the phase domain size increases to more than 20 μm, the interfacial compatibilization zone is poorly bonded, and the tensile strength decreases to below 12 MPa. The optimal content is 15-16% by weight, at which point the tensile strength retention rate is greater than 85%, and the degradation rate in soil after 2 years is greater than 92%.

[0062] 1.3 Coated Ferric Stearate and Manganese Stearate Composite Pro-oxidant System

[0063] In the coated ferric stearate and manganese stearate composite oxidant, the mass ratio of ferric stearate to manganese stearate is (1.5-2.5):1, preferably 2:1, the coating layer is stearic acid, and the amount of stearic acid is 10%-15% of the total mass of the oxidant.

[0064] Ferric stearate contains ferric ions, which exhibit multivalent state changes and can catalyze the oxidation of polyethylene, promote the decomposition of hydroperoxides, and accelerate molecular chain breakage. Manganese stearate contains divalent manganese ions, which have higher catalytic activity than ferric ions and can significantly shorten the induction period. When these two are combined in a 2:1 mass ratio to form coated ferric stearate and manganese stearate composite oxidant particles, a balance between the induction period and degradation rate can be achieved. Iron provides moderate catalytic activity, while manganese accelerates the degradation process, making the degradation more uniform and controllable.

[0065] Coating the coated ferric stearate and manganese stearate composite oxidant particles 9 with stearic acid can control the release rate of the particles, avoiding excessive consumption during processing and initial use. When the dosage of the coated ferric stearate and manganese stearate composite oxidant particles 9 is below 0.4%, the catalytic activity is insufficient, and the degradation rate after 2 years of soil burial is less than 80%. When the dosage is above 0.6%, the induction period is shortened to less than 18 months, and the tensile strength retention rate during the service life is less than 75%. The optimal dosage is 0.5% by weight, at which point the induction period is 24 months, and the degradation rate after 2 years of soil burial is greater than 90%.

[0066] 1.4 Induction Period Regulation System – Ethyl cellulose-coated antioxidant microcapsules

[0067] The core material of the ethyl cellulose-coated antioxidant microcapsule 7 is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of (1.5-2.5):1, preferably 2:1; the wall material is ethyl cellulose wall material 8 with an ethyl oxygen content of 44%-50% and a viscosity of 10-50 mPa·s (test conditions: 5% toluene and ethanol solution, 25℃); the coating rate of the ethyl cellulose-coated antioxidant microcapsule 7 is 30%-40%, the particle size is 50-150 μm, and the release half-life under water extraction conditions at 37℃ is 18-24 months.

[0068] Antioxidant 1010 is a hindered phenolic antioxidant that can capture free radicals and interrupt the oxidation chain reaction; Antioxidant 168 is a phosphite antioxidant that can decompose hydroperoxides. The synergistic effect is optimal when the two are combined in a 2:1 mass ratio, increasing antioxidant efficiency by more than 30%. By encapsulating the antioxidants in ethyl cellulose wall material 8 to form ethyl cellulose-encapsulated antioxidant microcapsules 7, sustained-release control of the antioxidants is achieved, prolonging their effective action time and thus precisely regulating the induction period.

[0069] When the particle size of the ethyl cellulose-coated antioxidant microcapsules 7 is less than 50 μm, the encapsulation rate is low, and the release is too rapid; when the particle size is greater than 150 μm, dispersion in the polyethylene matrix phase 4 is difficult. When the encapsulation rate is less than 30%, the sustained-release effect is not obvious; when it is greater than 40%, the initial release is insufficient, and the induction period is too long. When the dosage of the ethyl cellulose-coated antioxidant microcapsules 7 is less than 0.3%, the induction period is shortened to less than 20 months; when it is greater than 0.5%, the induction period is extended to more than 30 months, and degradation is delayed. The optimal dosage is 0.4% by weight, at which point the induction period is 24 months and the degradation period is 12 months.

[0070] 1.5 Compatibilizer – Maleic anhydride-grafted polyethylene

[0071] The grafting rate of maleic anhydride-grafted polyethylene is 1.0%-1.5%, with an optimal grafting rate of 1.2%.

[0072] Maleic anhydride-grafted polyethylene has polar maleic anhydride groups grafted onto its molecular chains. These groups can form hydrogen bonds or ester bonds with the hydroxyl groups of the thermoplastic starch island phase 5. Simultaneously, its polyethylene backbone is compatible with the polyethylene matrix phase 4, thus acting as a "bridge" between the thermoplastic starch island phase 5 and the polyethylene matrix phase 4, forming an interfacial compatibility zone 3 and improving interfacial compatibility. When the grafting rate is 1.2%, the interfacial bonding strength increases by more than 50%.

[0073] When the content of maleic anhydride-grafted polyethylene is less than 3%, the improvement in interfacial compatibility in the compatibility zone 3 is not significant, and the tensile strength is less than 13 MPa. When it is higher than 5%, the cost increases, and excessive maleic anhydride-grafted polyethylene may accumulate in the interfacial compatibility zone 3, which may actually reduce interfacial adhesion. The optimal content is 4% by weight, at which point the tensile strength increases by 20%, and the elongation at break is retained by more than 90%.

[0074] 1.6 Rigid Filler – Nano-Calcium Carbonate

[0075] The nano-calcium carbonate particles 6 have a particle size of 50-100 nm and are surface-treated with aluminate coupling agent or stearic acid, with an activation degree greater than 95%.

[0076] Nano-calcium carbonate particles 6 can play a role in rigidity enhancement, improve the modulus and dimensional stability of the material, and compensate for the strength loss caused by the addition of thermoplastic starch island phase 5. At the same time, the hydroxyl groups and rough structure on the surface of nano-calcium carbonate particles 6 are conducive to the adhesion of microbial colonies 11, forming a biofilm 12 on the matrix surface 10, which promotes biodegradation. Nano-calcium carbonate particles 6 can also act as a heterogeneous nucleating agent for polyethylene, refine the grains, and improve the strength of the material.

[0077] When the dosage of nano-calcium carbonate particles 6 is less than 5%, the reinforcing effect is not obvious; when it is higher than 8%, the agglomeration of nano-calcium carbonate particles 6 intensifies, and the tensile strength decreases. The optimal dosage is 6-7% by weight, at which point the tensile strength increases by 10%-15%, and the amount of microbial colonies 11 attached increases by 30%.

[0078] II. Preparation Method

[0079] 2.1 Preparation of Coated Ferric Stearate and Manganese Stearate Composite Pro-oxidant

[0080] The coated iron stearate and manganese stearate composite oxidant particles 9 can be prepared by melt coating, solvent coating or mechanical coating, specifically including:

[0081] (1) Melt coating method: Ferric stearate and manganese stearate are mixed evenly at a mass ratio of (1.5-2.5):1 to obtain a composite oxidant mixture. The stearic acid coating layer is heated to 60-80℃ to melt. The composite oxidant mixture is slowly added to the molten stearic acid under stirring at 500-1000 rpm. After stirring for 10-15 min, the mixture is cooled to room temperature and then pulverized to a particle size of 50-200 μm to obtain coated ferric stearate and manganese stearate composite oxidant particles 9. The process parameters of the melt coating method are: coating temperature 70-75℃, stirring speed 800 rpm, stirring time 12 min, cooling method is natural cooling, coating rate 15%-25%, and coating layer thickness 0.5-2 μm.

[0082] (2) Solvent coating method: Iron stearate and manganese stearate are dissolved in hexane at a mass ratio of (1.5-2.5):1 to prepare a 15%-20% composite oxidant solution, and stirred at 40-60℃. Stearic acid is dissolved in the same volume of hexane to prepare a 5%-10% coating layer solution. The two solutions are mixed and stirred at 2000-3000 rpm for 20-30 min to uniformly coat the surface of the composite oxidant. The solvent is removed by vacuum evaporation, and the mixture is dried under vacuum and pulverized to a particle size of 50-200 μm to obtain coated iron stearate and manganese stearate composite oxidant particles 9. The process parameters of the solvent coating method are: dissolution temperature 50℃, stirring speed 2500 rpm, stirring time 25 min, vacuum drying temperature 40-50℃, vacuum degree 0.08-0.09 MPa, and drying time 4-6 h.

[0083] (3) Mechanical coating method: Ferric stearate and manganese stearate are mixed evenly at a mass ratio of (1.5-2.5):1 to obtain a composite oxidant mixture, and stearic acid powder is used as the coating material; the composite oxidant mixture and stearic acid powder are added to a high-speed mixer at a mass ratio of (85-90):(10-15), and stirred at high speed for 15-25 minutes at 80-100℃ and 1500-2500rpm, so that stearic acid is uniformly coated on the surface of the composite oxidant particles under the action of frictional heat and mechanical force; after cooling to room temperature, it is passed through a 100-mesh sieve to obtain coated ferric stearate and manganese stearate composite oxidant particles 9. The process parameters of the mechanical coating method are: mixing temperature 90℃, stirring speed 2000rpm, and mixing time 20min.

[0084] 2.2 Preparation of ethyl cellulose-coated antioxidant microcapsules

[0085] Ethyl cellulose-coated antioxidant microcapsules were prepared by solvent evaporation method 7, such as Figure 1 As shown: Antioxidant 1010 and Antioxidant 168, with a mass ratio of (1.5-2.5):1, were dissolved in dichloromethane to prepare an oil phase solution with a concentration of 10%-15%. Ethyl cellulose was added to the oil phase solution and stirred until completely dissolved, so that the concentration of ethyl cellulose was 5%, forming a precursor of ethyl cellulose wall material 8. A 1% polyvinyl alcohol aqueous solution was prepared as the aqueous phase. The oil phase was slowly added to the aqueous phase and emulsified at high speed of 5000-8000 rpm for 5-10 min to form an oil-in-water emulsion. The emulsion was transferred to a rotary evaporator and evaporated under reduced pressure at 35-45℃ and a vacuum degree of 0.08-0.09 MPa to remove dichloromethane, thereby solidifying the ethyl cellulose-coated antioxidant microcapsules 7. Finally, the microcapsules were filtered, washed, and vacuum dried at 40℃ to obtain the ethyl cellulose-coated antioxidant microcapsules 7.

[0086] The optimized values ​​for the above process parameters are: oil phase antioxidant concentration 12%, emulsification speed 6000 rpm, emulsification time 8 min, evaporation temperature 40℃, and vacuum degree 0.085 MPa. Under these conditions, the ethyl cellulose-coated antioxidant microcapsules 7 have a uniform particle size distribution, such as... Figure 2 As shown, the coating rate is stable at around 35%, and the release half-life is 21 months, which fully meets the requirements for induction period regulation.

[0087] 2.3 Preparation of thermoplastic starch

[0088] Corn starch or cassava starch and glycerol are added to a high-speed mixer at a mass ratio of (6.5-7.5):(2.5-3.5) and mixed at 1000-1500 rpm for 5-10 minutes. The uniformly mixed material is then added to a twin-screw extruder and extruded and granulated at 120-140℃ and a screw speed of 200-300 rpm to obtain thermoplastic starch, which is used to form thermoplastic starch island phase 5 and thermoplastic starch dispersed phase particles 2.

[0089] The optimized values ​​for the above process parameters are: mixing speed 1200 rpm, mixing time 8 min, extrusion temperature 130℃, and screw speed 250 rpm. Under these conditions, the starch is fully plasticized, and the mechanical properties and water resistance of the formed thermoplastic starch island phase 5 reach the optimal balance.

[0090] 2.4 Melt Blending Granulation

[0091] Low-density polyethylene, linear low-density polyethylene, thermoplastic starch, maleic anhydride-grafted polyethylene, and nano-calcium carbonate particles 6 are added to a high-speed mixer according to the formula ratio and premixed for 3-5 minutes. Then, coated iron stearate and manganese stearate composite oxidant particles 9 and ethyl cellulose-coated antioxidant microcapsules 7 are added and mixed for another 2-3 minutes. The premixed material is then added to a twin-screw extruder for melt blending. The twin-screw extruder is divided into a feeding section, a compression section, a homogenization section, and a die head section. The temperatures of each section are controlled sequentially as follows: feeding section 160-170℃, compression section 175-185℃, homogenization section 190-200℃, and die head 185-195℃. The screw speed is 200-300 rpm. A vacuum devolatilization port is set in the homogenization section, and the vacuum degree is controlled at -0.06 to -0.09 MPa. The material residence time is 2-4 minutes. The extrudate is water-cooled and pelletized to obtain composite material particles, which are used to prepare drip irrigation tape tubes 16.

[0092] The optimized values ​​for the above process parameters are: extrusion temperature 190℃, screw speed 250rpm, vacuum degree -0.07MPa, and residence time 3min. This temperature ensures that the polyethylene matrix phase 4 and the thermoplastic starch island phase 5 are fully melted and mixed, while avoiding thermal degradation of thermoplastic starch and premature cracking of ethyl cellulose wall material 8. This speed provides sufficient shear force to achieve uniform dispersion of nano-calcium carbonate particles 6, coated iron stearate and manganese stearate composite oxidizing agent particles 9, and ethyl cellulose-coated antioxidant microcapsules 7, while avoiding material degradation due to excessive shear heat. Vacuum devolatilization can effectively remove residual moisture and low-molecular-weight volatiles, preventing bubbles and odors from appearing in the drip irrigation tape tube 16.

[0093] 2.5 Drip tape molding

[0094] Composite material particles are added to a single-screw extruder and extruded at a temperature of 180-200℃. The die temperature is controlled at 170-180℃, the traction speed is 30-50m / min, and the cooling water temperature is 15-25℃. After extrusion, molding, cooling, traction, and winding, a drip irrigation tape tube body 16 product containing a single wing 13, a labyrinth flow channel 14, and a water outlet 15 is obtained.

[0095] The optimized values ​​for the above process parameters are: extrusion temperature 190℃, die temperature 175℃, traction speed 40m / min, and cooling water temperature 20℃. Under these conditions, the drip irrigation tape produced has uniform wall thickness of the tube body 16, smooth substrate surface 10, clearly formed labyrinth channels 14, accurate outlet size 15, and a product qualification rate greater than 95%, meeting the requirements of industrial production.

[0096] III. Examples

[0097] Example 1 (Optimal Formulation)

[0098] Formulation composition (by weight percentage): 50% low-density polyethylene with a melt flow index of 2.5 g / 10 min, 25% linear low-density polyethylene with a melt flow index of 2.0 g / 10 min, 15% thermoplastic starch with a glycerol content of 30%, 90.5% coated iron stearate and manganese stearate composite pro-oxidant particles coated with stearic acid in a 2:1 mass ratio, 70.4% antioxidant microcapsules coated with ethyl cellulose with a coating rate of 35%, 4% maleic anhydride grafted polyethylene with a grafting rate of 1.2%, and 65% surface-treated nano-calcium carbonate particles with a particle size of 50 nm.

[0099] Preparation method: The preparation is carried out according to steps 2.1 to 2.5 above, and the optimized process parameters are used in each step.

[0100] Performance test results: initial tensile strength 16.2 MPa, elongation at break 320%, tensile strength retention rate 83% after 24 months, degradation rate 93% after 2 years of soil burial, microplastic residue 3.2%, induction period 24 months, and good formation of the labyrinth channel 14 and outlet 15 of the drip irrigation tape body 16.

[0101] Example 2 (High thermoplastic starch formulation)

[0102] Formulation composition (by weight percentage): 45% low-density polyethylene with a melt flow index of 2.5 g / 10 min, 22% linear low-density polyethylene with a melt flow index of 2.0 g / 10 min, 18% thermoplastic starch with a glycerol content of 30%, 0.6% composite oxidant coated with stearic acid and containing iron stearate and manganese stearate in a mass ratio of 2:1, 0.5% antioxidant microcapsules coated with ethyl cellulose with a coating rate of 35%, 5% maleic anhydride grafted polyethylene with a grafting rate of 1.2%, and 6% nano-calcium carbonate with a particle size of 50 nm and surface treatment.

[0103] Preparation method: Same as in Example 1.

[0104] Performance test results: initial tensile strength 15.0 MPa, elongation at break 280%, tensile strength retention rate at 24 months 81%, degradation rate at 2-year soil burial 95%, microplastic residue 2.8%, induction period 23 months.

[0105] Note: The thermoplastic starch content is increased to 18%, further improving degradation performance, but the tensile strength is close to the industry standard lower limit of 14MPa, making it suitable for applications where strength requirements are not high.

[0106] Example 3 (Low thermoplastic starch formulation)

[0107] Formulation composition (by weight percentage): 55% low-density polyethylene with a melt flow index of 2.5 g / 10 min, 28% linear low-density polyethylene with a melt flow index of 2.0 g / 10 min, 12% thermoplastic starch with a glycerol content of 30%, 0.4% composite oxidant coated with stearic acid and containing iron stearate and manganese stearate in a mass ratio of 2:1, 0.3% antioxidant microcapsules coated with ethyl cellulose with a coating rate of 35%, 3% maleic anhydride grafted polyethylene with a grafting rate of 1.2%, and 5% nano-calcium carbonate with a particle size of 50 nm and surface treatment.

[0108] Preparation method: Same as in Example 1.

[0109] Performance test results: initial tensile strength 17.5 MPa, elongation at break 350%, tensile strength retention rate 85% after 24 months, degradation rate 90% after 2 years of soil burial, microplastic residue 4.5%, and induction period 25 months.

[0110] Note: The thermoplastic starch content is reduced to 12%, which improves mechanical properties, but the degradation rate is close to the design lower limit of 90%, making it suitable for applications with high strength requirements.

[0111] Example 4 (High Nano Calcium Carbonate Formulation)

[0112] Formulation composition (by weight percentage): 48% low-density polyethylene with a melt flow index of 2.5 g / 10 min, 24% linear low-density polyethylene with a melt flow index of 2.0 g / 10 min, 15% thermoplastic starch with a glycerol content of 30%, 0.5% composite oxidant coated with stearic acid and containing iron stearate and manganese stearate in a mass ratio of 2:1, 0.4% antioxidant microcapsules coated with ethyl cellulose with a coating rate of 35%, 4% maleic anhydride grafted polyethylene with a grafting rate of 1.2%, and 8% nano-calcium carbonate with a particle size of 50 nm and surface treatment.

[0113] Preparation method: Same as in Example 1.

[0114] Performance test results: initial tensile strength 16.8 MPa, elongation at break 300%, tensile strength retention rate after 24 months 84%, degradation rate after 2 years of soil burial 94%, microplastic residue 2.5%, induction period 24 months.

[0115] Note: The nano-calcium carbonate content is increased to 8%, resulting in increased microbial adhesion, more thorough degradation, and the lowest microplastic residue.

[0116] Example 5 (Formulations with different iron-manganese ratios)

[0117] Formulation composition (by weight percentage): 50% low-density polyethylene with a melt flow index of 2.5 g / 10 min, 25% linear low-density polyethylene with a melt flow index of 2.0 g / 10 min, 15% thermoplastic starch with a glycerol content of 30%, 0.5% composite oxidant coated with stearic acid and containing iron stearate and manganese stearate in a mass ratio of 3:1, 0.4% antioxidant microcapsules coated with ethyl cellulose with a coating rate of 35%, 4% maleic anhydride grafted polyethylene with a grafting rate of 1.2%, and 5% nano-calcium carbonate with a particle size of 50 nm and surface treatment.

[0118] Preparation method: Same as in Example 1.

[0119] Performance test results: initial tensile strength 16.3 MPa, elongation at break 325%, tensile strength retention rate after 24 months 86%, degradation rate after 2 years in soil 88%, microplastic residue 6.0%, induction period 26 months.

[0120] Note: Increasing the ratio of ferric stearate to manganese stearate to 3:1 prolongs the induction period, but reduces the degradation rate and increases the amount of microplastic residue, proving that a mass ratio of ferric stearate to manganese stearate of 2:1 is the optimal ratio.

[0121] IV. Comparative Example

[0122] Comparative Example 1 (Pure Polyethylene Drip Irrigation Tape)

[0123] Formulation composition (by weight percentage): 70% low-density polyethylene, 30% linear low-density polyethylene.

[0124] Preparation method: Same as steps 2.4 to 2.5 of Example 1.

[0125] Performance test results: initial tensile strength 17.8 MPa, elongation at break 380%, tensile strength retention rate after 24 months 96%, degradation rate after 2 years in soil 3%, and microplastic residue 97%.

[0126] Comparative Example 2 (Traditional Oxidation-Biodegradable Drip Irrigation Tape)

[0127] Formulation composition (by weight percentage): 65% low-density polyethylene, 25% linear low-density polyethylene, 8% unplasticized starch, 0.3% uncoated manganese stearate, and 0.2% uncoated antioxidant 1010.

[0128] Preparation method: Same as steps 2.4 to 2.5 of Example 1.

[0129] Performance test results: initial tensile strength 14.5 MPa, elongation at break 220%, tensile strength retention rate after 24 months 72%, degradation rate after 2 years of soil burial 78%, microplastic residue 15%, induction period 20±4 months.

[0130] Comparative Example 3 (Antioxidant-free microencapsulation)

[0131] Formulation composition: Antioxidant 1010 and Antioxidant 168 are added directly at a mass ratio of 2:1 (uncoated), with a dosage of 0.4%. Other components and dosages are the same as in Example 1.

[0132] Preparation method: Same as in Example 1.

[0133] Performance test results: initial tensile strength 16.0 MPa, elongation at break 350%, tensile strength retention rate after 24 months 65%, induction period 18 months; antioxidant loss rate during processing 35%, poor antioxidant dispersion uniformity, and obvious local oxidation discoloration; degradation rate after 2 years of soil burial 55%, number average molecular weight after degradation 4500 g / mol, microplastic residue 25%, molecular weight distribution index of degradation products 6.5; local cracks and pores appeared on the material surface, and the mechanical properties decayed unevenly.

[0134] Comparative conclusions: Without microencapsulation, the antioxidant loss rate during processing reaches 35%, while with microencapsulation, the antioxidant loss rate is only 5%-10%. Antioxidants are consumed in large quantities during processing and the initial stages of use, resulting in a shortened induction period from the designed 24 months to 18 months. The tensile strength retention rate after 24 months is only 65%, lower than the 80% requirement for use, indicating significant performance degradation during the service life. Simultaneously, the degradation products have a wide molecular weight distribution, with microplastic residues reaching as high as 25%, indicating incomplete degradation. This demonstrates the crucial role of microencapsulation in precisely controlling the induction period and ensuring uniform degradation.

[0135] Comparative Example 4 (without maleic anhydride-grafted polyethylene compatibilizer)

[0136] Formulation composition: Maleic anhydride-grafted polyethylene without addition, other components and dosages are the same as in Example 1.

[0137] Preparation method: Same as in Example 1.

[0138] Performance test results: initial tensile strength 11.5 MPa, elongation at break 150%.

[0139] Comparative conclusion: Without compatibilizer, the interfacial adhesion between thermoplastic starch and polyethylene is poor, and the mechanical properties are significantly reduced, proving the key role of compatibilizer in improving interfacial compatibility.

[0140] Comparative Example 5 (without nano-calcium carbonate)

[0141] Formulation composition: No nano-calcium carbonate added; other components and dosages are the same as in Example 1.

[0142] Preparation method: Same as in Example 1.

[0143] Performance test results: initial tensile strength 14.8 MPa, degradation rate of 85% after 2 years of soil burial, and microplastic residue of 8%.

[0144] Comparative conclusion: Without nano-calcium carbonate, thermoplastic starch exhibits poor dispersibility, decreased mechanical properties, and incomplete degradation, demonstrating the crucial role of nano-calcium carbonate in dispersibility and degradation performance.

[0145] Comparative Example 6 (Single pro-oxidant – ferric stearate only)

[0146] Formula composition: Only 0.5% ferric stearate is used, and the other components and their amounts are the same as in Example 1.

[0147] Preparation method: Same as in Example 1.

[0148] Performance test results: 82% degradation rate after 2 years of soil burial, number average molecular weight after degradation is 3500 g / mol, and microplastic residue is 12%.

[0149] Comparative conclusion: When using ferric stearate as a single oxidizing agent, the degradation rate is slow, the degradation products have high molecular weight, and there are many microplastic residues, demonstrating the synergistic effect of the ferric stearate and manganese stearate composite system.

[0150] Comparative Example 7 (Single pro-oxidant – manganese stearate only)

[0151] Formulation composition: Only 0.5% manganese stearate is used, and the other components and their amounts are the same as in Example 1.

[0152] Preparation method: Same as in Example 1.

[0153] Performance test results: 58% tensile strength retention rate after 24 months, 16-month induction period, and 95% degradation rate after 2 years of soil burial.

[0154] Comparative conclusion: When using manganese stearate as a single oxidizing agent, the induction period is too short and the performance deteriorates severely during the service life, proving the key role of the iron stearate and manganese stearate composite system in regulating the induction period.

[0155] V. Test methods for key performance parameters

[0156] To ensure the repeatability and full disclosure of the technical solution, this invention describes the test methods for the following key performance parameters:

[0157] Test method for grafting rate of maleic anhydride-grafted polyethylene: The grafting rate of maleic anhydride was determined by acid-base titration. The maleic anhydride-grafted polyethylene sample was dissolved in xylene, and excess potassium hydroxide ethanol solution was added. The mixture was refluxed at 80℃ for 2 hours to hydrolyze the maleic anhydride groups and react with potassium hydroxide. After cooling, the remaining potassium hydroxide was titrated with standard hydrochloric acid solution using phenolphthalein as an indicator. The grafting rate was calculated using the following formula: Grafting rate = (V0 - V1) × CHCl × 98.06 / (2 × m) × 100%, where V0 is the volume of hydrochloric acid consumed in the blank (mL); V1 is the volume of hydrochloric acid consumed in the sample (mL); CHCl is the hydrochloric acid concentration (mol / L); and m is the mass of the maleic anhydride-grafted polyethylene sample (g).

[0158] The method for testing the microcapsule encapsulation rate is as follows: The encapsulation rate is determined by solvent extraction. Weigh the microcapsule sample m1 (g) and place it in a Soxhlet extractor. Extract with dichloromethane for 4 hours to remove unencapsulated antioxidants. Dry the extracted microcapsules to a constant weight m2 (g). Encapsulation rate = (m1-m2) / m1 × 100%, where m1-m2 is the mass of the encapsulated antioxidants, and m1 is the total mass of the microcapsules.

[0159] Release half-life testing conditions: The release half-life of antioxidant microcapsules was determined using the 37℃ water extraction method. Microcapsule samples were placed in dialysis bags and immersed in a phosphate buffer solution with a pH of 7.4. Release tests were conducted at a constant temperature of 37±0.5℃ with a stirring rate of 100 rpm, and the release medium was replaced every 24 hours. Antioxidant concentration in the released solution was measured periodically, and a cumulative release curve was plotted. The release half-life t1 / 2 was calculated using first-order kinetic equations.

[0160] Screening conditions for microplastic residue: After washing the degraded material sample with deionized water, it was sequentially passed through standard test sieves with apertures of 5 mm, 1 mm, and 38 μm, under the conditions of a vibration frequency of 3000 times / min and a screening time of 10 min. The residue on the sieve (particles with a diameter greater than 38 μm) was collected, dried, and weighed. Microplastic residue = mass of residue on the sieve / total mass of sample × 100%. Degradation products with a number average molecular weight less than 1000 g / mol and a particle size less than 38 μm were considered completely biodegraded and were not included in the microplastic residue count.

[0161] It should be noted that, in this invention, although the specification describes the embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An oxidatively-biodegradable drip irrigation tape material with controlled induction period, characterized in that, The product comprises, by weight percentage: 65%-85% matrix resin, 12%-18% thermoplastic starch, 0.4%-0.6% coated iron stearate and manganese stearate composite pro-oxidant, 0.3%-0.5% ethyl cellulose-coated antioxidant microcapsules, 3%-5% maleic anhydride-grafted polyethylene, and 5%-8% nano-calcium carbonate; the matrix resin is a mixture of low-density polyethylene and linear low-density polyethylene in a mass ratio of (1.5-2.5):1; the ethyl cellulose-coated antioxidant microcapsules have a coating rate of 30%-40% and a release half-life of 18-24 months under water extraction conditions at 37°C.

2. The material of claim 1, wherein, The melt flow index of the low-density polyethylene is 2.0-3.0 g / 10 min, and the melt flow index of the linear low-density polyethylene is 1.5-2.5 g / 10 min.

3. The controllably inducible bi-oxidative degradable drip irrigation tape material according to claim 1, characterized in that, The grafting rate of the maleic anhydride-grafted polyethylene is 1.0%-1.5%; the nano-calcium carbonate is surface-treated with an aluminate coupling agent or stearic acid.

4. The controllably inducibly biodegradable drip irrigation tape material according to claim 1, wherein, The thermoplastic starch is prepared by mixing starch and glycerol in a mass ratio of (6.5-7.5):(2.5-3.5), and the starch has an amylose content of 20%-30%.

5. The controllably inducibly biodegradable drip irrigation tape material according to claim 1, wherein, The mass ratio of iron stearate to manganese stearate in the coated iron stearate and manganese stearate composite oxidant is (1.5-2.5):1, the coating layer is stearic acid, and the amount of stearic acid is 10%-15% of the total mass of the oxidant.

6. The controllably inducibly biodegradable drip irrigation tape material according to claim 1, wherein, The core material of the ethyl cellulose-coated antioxidant microcapsules is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of (1.5-2.5):1; the particle size of the microcapsules is 50-150 μm.

7. A method of making the controllably inducible biodegradable drip irrigation tape material according to any one of claims 1-6, characterized in that, Includes the following steps: S1: Prepare a coated iron stearate and manganese stearate composite oxidant by one of the following methods: melt coating, solvent coating or mechanical coating. S2: The preparation of antioxidant microcapsules coated with ethyl cellulose by solvent evaporation method includes: dissolving antioxidant 1010, antioxidant 168 and ethyl cellulose in dichloromethane to prepare an oil phase; adding the oil phase to a polyvinyl alcohol aqueous solution and emulsifying it at high speed of 5000-8000 rpm for 5-10 min to form an oil-in-water emulsion; removing the solvent by vacuum evaporation; and then filtering, washing and drying. S3: Preparation of thermoplastic starch, specifically including: mixing starch and glycerol at a mass ratio of (6.5-7.5):(2.5-3.5) and then plasticizing and granulating by twin-screw extrusion; S4: After premixing the matrix resin, thermoplastic starch, maleic anhydride-grafted polyethylene and nano calcium carbonate for 3-5 minutes, add the coated iron stearate and manganese stearate composite oxidant and ethyl cellulose-coated antioxidant microcapsules and continue mixing for 2-3 minutes to obtain the premix. S5: The premixed material is added to a twin-screw extruder for melt blending, extrusion, and granulation. The extrusion temperature is 160-200℃, the screw speed is 200-300rpm, the homogenization section is equipped with a vacuum devouring device, the vacuum degree is -0.06~-0.09MPa, and the length-to-diameter ratio of the twin-screw extruder is 40:1-48:1 to obtain composite material particles. S6: extruding the composite particles into a drip irrigation tape product.

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