Biodegradable polyester composite material and application thereof

Abstract

The invention provides a biodegradable polyester composite material and application thereof, the biodegradable polyester composite material comprises, by weight, 70-95 parts of biodegradable polyester, 2-10 parts of polylactic acid, and 3-20 parts of an inorganic filler; the ratio of the melt index of the polylactic acid boiled in water at 80 DEG C for 2 hours to the initial melt index is 1.1-5. A film material prepared from the biodegradable polyester composite material has good damp-heat aging resistance.

Description

A biodegradable polyester composite material and its application Technical Field

[0001] This invention belongs to the field of biodegradable materials technology, specifically relating to a biodegradable polyester composite material and its applications. Background Technology

[0002] Biodegradable mulch films are a type of plastic mulch film that can degrade under natural environmental conditions through the action of microorganisms. After microorganisms such as bacteria, fungi, and actinomycetes erode the plastic film, the polymer components undergo hydrolysis, ionization, or protonation due to cell growth, resulting in mechanical damage and fragmentation into oligomer fragments. Enzymes secreted by fungi or bacteria decompose or oxidize water-soluble polymers into water-soluble fragments, generating new small molecule compounds, until finally decomposing into CO2 and H2O. Among these biodegradable mulch films, biodegradable polyester mulch films are the most common and have received widespread attention. However, when biodegradable mulch films are exposed to water, heat, and light in the field, their mechanical properties easily deteriorate, especially the maximum puncture force decreases after aging, making it easier for weeds to puncture the mulch film, thus reducing its entropy-preserving effect on crops.

[0003] Therefore, developing a polyester composite material with excellent resistance to damp heat aging is an urgent problem to be solved in this field. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a biodegradable polyester composite material and its applications. The membrane material made from the biodegradable polyester composite material exhibits excellent resistance to damp heat aging and a high retention rate of maximum puncture force before and after aging, thus improving the entropy retention effect on crops.

[0005] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a biodegradable polyester composite material, wherein, by weight, the biodegradable polyester composite material comprises 70-95 parts of biodegradable polyester, 2-10 parts of polylactic acid, and 3-20 parts of inorganic filler; the ratio of the melt index of the polylactic acid after boiling in water at 80°C for 2 hours to the initial melt index is 1.1-5.

[0006] In this invention, the ratio of the melt index of polylactic acid (PLA) after boiling in water at 80°C for 2 hours to its initial melt index is too low. This results in excessively dense PLA with high crystallinity and poor compatibility with the polyester system, leading to microscopic defects at the phase interface of the composite material. Consequently, water molecules can easily penetrate, causing a decline in the material's resistance to damp heat aging. Conversely, a ratio that is too high makes the material prone to degradation, also resulting in poor resistance to damp heat aging. Therefore, by using PLA with a specific melt index ratio before and after boiling in water, combined with biodegradable polyester and inorganic fillers in specific amounts, the resulting membrane material exhibits excellent resistance to damp heat aging and maintains a high maximum puncture force even after aging.

[0007] In this invention, 70 to 95 parts of biodegradable polyester can be, for example, 70 parts, 72 parts, 74 parts, 76 parts, 78 parts, 80 parts, 82 parts, 84 parts, 86 parts, 88 parts, 90 parts, 92 parts, 94 parts or any range of the above values, and more preferably 77 to 89 parts.

[0008] In this invention, the biodegradable polyester composite material contains ≥60% by mass, preferably 70-85%, and more preferably 78-82%.

[0009] In this invention, the weight-average molecular weight (Mw) of the biodegradable polyester is 50,000 to 200,000 Da; it can be obtained by gel permeation chromatography.

[0010] In this invention, 2 to 10 parts of polylactic acid, for example, can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts or any of the above values, preferably 3.5 to 6.5 parts.

[0011] In this invention, the mass percentage of polylactic acid in the biodegradable polyester composite material is ≤10%, preferably 2~9%, and more preferably 4.5~6.5%.

[0012] In this invention, the melt index of the polylactic acid is 2~50g / 10min at 190℃ and 2.16kg.

[0013] In this invention, the melt index of the polylactic acid can be measured by the ISO 1133-1:2022 standard.

[0014] In this invention, the ratio of the melt index of polylactic acid after boiling in water at 80°C for 2 hours to the initial melt index is 1.1 to 5, for example, it can be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5 or any of the above values; preferably 1.2 to 4, more preferably 1.5 to 3.

[0015] In this invention, the initial melt index of polylactic acid is the melt index of polylactic acid boiled in water for 0 hours; the test conditions for melt index are 190℃ and 2.16kg.

[0016] Preferably, the polylactic acid includes a copolymer of D-lactic acid and L-lactic acid (PLLA-PDLA copolymer).

[0017] In this invention, polylactic acid (PLA) can be obtained commercially or prepared using conventional methods. Exemplarily, the preparation method includes: performing a ring-opening polymerization reaction on lactide in the presence of a catalyst to obtain the PLA; the lactide comprises, by weight, 58-99.2 parts of L-lactide and 0.8-42 parts of meso-lactide; the total mass of the L-lactide and meso-lactide is 100 parts; based on the mass of 100 parts of lactide, the mass of the catalyst is 0.001-0.003 parts, and the catalyst comprises stannous octoate; the ring-opening polymerization reaction includes a first stage, a second stage, and a third stage, performed sequentially. The reaction consists of two stages: the first stage has a reaction temperature of 132-138℃, a pressure of 1800-2200Pa, and a time of 3.5-4.5h; the second stage has a reaction temperature of 168-172℃, a pressure of 450-550Pa, and a time of 5.5-6.5h; the third stage is a passivation treatment stage, in which the temperature is lowered to 148-152℃, a passivating agent is added and treated for 25-35min, followed by granulation, crystallization, and drying to obtain the polylactic acid; the passivating agent includes zinc phosphate, and the mass of the passivating agent is 0.0002-0.0004 parts per 100 parts of lactide.

[0018] In this invention, the polylactic acid can also be prepared by the following method, which includes the following steps: In the presence of a catalyst, lactide is subjected to a ring-opening polymerization reaction at 162-168°C and 1800-2200 Pa for 10-14 hours. After the reaction, the sample is removed, cooled, crushed, re-extruded into strips, granulated, crystallized, and dried to obtain the polylactic acid. By weight, the lactide comprises 58-99.2 parts of L-lactide and 0.8-42 parts of meso-lactide; the total mass of the L-lactide and meso-lactide is 100 parts; based on the mass of 100 parts of lactide, the mass of the catalyst is 0.001-0.003 parts, and the catalyst comprises stannous octoate.

[0019] In this invention, the polylactic acid can also be obtained by processing commercially available polylactic acid, such as by melting and extruding commercially available polylactic acid with an epoxy chain extender and a carbodiimide compound at a mass ratio of 98~99.1:0.6~0.71:0.2~0.31, followed by water rinsing, pelletizing, and drying to obtain the polylactic acid; wherein the temperature of the melt extrusion is 80~200℃ (i.e., the different temperature ranges are 80℃, 120℃, 180℃, 180℃, 180℃, 180℃, 200℃ respectively).

[0020] Preferably, the biodegradable polyester comprises an aliphatic-aromatic copolyester.

[0021] In this invention, the aliphatic-aromatic copolyester comprises diacid residues and diol residues; the diacid residues comprise aromatic diacid residues and / or aliphatic diacid residues, preferably aromatic diacid residues comprise terephthalic acid residues and / or furanyl dicarboxylic acid residues; preferably aliphatic diacid residues comprise at least one of adipic acid residues, succinic acid residues, azelaic acid residues, sebacic acid residues, or brassic acid residues; the diol residues preferably comprise propylene glycol residues and / or butanediol residues. The molar percentage of aromatic diacid residues in the diacid residues is 5-90 mol%, preferably 20-70 mol%.

[0022] In this invention, the term "residue" refers to a structural unit introduced into the polyester molecular chain by a related monomer through a polycondensation reaction. Specifically, aromatic diacids and / or their derivatives are introduced into the polyester molecular chain through a polycondensation reaction to form aromatic diacid residues; aliphatic diacids and / or their derivatives are introduced into the molecular chain through a polycondensation reaction to form aliphatic diacid residues; the aromatic diacids include, but are not limited to, terephthalic acid, furanyl dicarboxylic acid, etc.; the aliphatic diacids include, but are not limited to, adipic acid, azelaic acid, sebacic acid, succinic acid, brassic acid, etc.; the derivatives include esters of aromatic diacids or esters of aliphatic diacids, such as diC1-C10 alkyl esters of aromatic diacids, diC1-C10 alkyl esters of aliphatic diacids, etc., wherein diC1-C10 alkyl esters exemplarily include, but are not limited to, dimethyl ester, diethyl ester, di-n-propyl ester, di-n-butyl ester, di-n-hexyl ester, di-n-decyl ester, etc.

[0023] Preferably, the aliphatic-aromatic copolyester comprises any one or a combination of at least two of polybutylene adipate terephthalate (PBAT), polybutylene sebacic acid terephthalate (PBSeT), and polybutylene terephthalate succinate (PBST).

[0024] Preferably, the inorganic filler includes any one or a combination of at least two of the following: talc, calcium carbonate, silica, montmorillonite, kaolin, chalk, gypsum, calcium chloride, iron oxide, dolomite, wollastonite, titanium dioxide, silicates, and mica; more preferably, any one or a combination of at least two of the following: talc, calcium carbonate, silica, montmorillonite, and kaolin.

[0025] Preferably, the inorganic filler has a D98 ≤ 15 μm, and can be, for example, 0.1 μm, 0.2 μm, 0.5 μm, 0.8 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm or any of the above values; preferably 1~13 μm, particularly preferably 4~10 μm.

[0026] In this invention, the D98 test method for the inorganic filler is determined in accordance with GB / T 19077.1-2008 "Particle size analysis by laser diffraction".

[0027] Preferably, the loose density of the inorganic filler is 0.1~0.9 g / cm³. 3 For example, it can be 0.12 g / cm³. 3 0.15g / cm3 0.18 g / cm 3 0.2 g / cm 3 0.22 g / cm 3 0.25 g / cm 3 0.28 g / cm 3 0.3 g / cm 3 0.32 g / cm 3 0.35 g / cm 3 0.38 g / cm 3 0.4 g / cm 3 0.42 g / cm 3 0.45 g / cm 3 0.48 g / cm 3 0.5 g / cm 3 0.52 g / cm 3 0.55 g / cm 3 0.58 g / cm 3 0.6 g / cm 3 0.62 g / cm 3 0.65 g / cm 3 0.68 g / cm 3 0.7g / cm 3 0.72 g / cm 3 0.75 g / cm 3 0.78 g / cm 3 0.8 g / cm 3 0.82 g / cm 3 0.85 g / cm 3 0.88 g / cm 3 Or any of the above values, more preferably 0.2~0.5 g / cm³. 3 .

[0028] In this invention, the inorganic filler can be obtained by purchasing commercially available products or by preparing them using conventional methods; for example, commercially available products can be ground to obtain inorganic fillers with a specific D98 and a specific loose density.

[0029] Preferably, the biodegradable polyester composite material further includes 0.4 to 8 parts by weight of additives, for example, 0.5 parts, 1 part, 1.5 parts, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts or any range between the above values.

[0030] Preferably, the additives include at least one of lubricant, antioxidant, compatibilizer, nucleating agent, colorant, light stabilizer, and hydrolysis resistant agent.

[0031] In this invention, the weight parts of the lubricant, antioxidant, compatibilizer, nucleating agent, colorant, light stabilizer or hydrolysis resistant agent are each independently 0.1 to 2 parts.

[0032] In this invention, the additives can be selected according to actual needs, as long as they can achieve the corresponding function and do not impair the effect of this invention.

[0033] For example, the lubricant can be used to enhance the slip properties (smoothing properties) during the extrusion process and as an additive to prevent the film surfaces from adhering to each other; the lubricant includes, but is not limited to, at least one of ethylene bis-stearamide (EBS), glyceryl monostearate, oleamide, erucamide, pentaerythritol stearate, polyethylene wax, and silicone lubricants.

[0034] For example, the antioxidant is an additive used to prevent decomposition by ozone or oxygen, to prevent oxidation during storage, and to prevent deterioration of the physical properties of the membrane; the antioxidant includes, but is not limited to, primary antioxidants, such as any one or a combination of at least two of 2,6-di-tert-butyl-p-cresol (BHT), 2,2'-methylene-bis(4-ethyl-6-tert-butylphenol), 2,2'-methylene-bis(4-methyl-6-tert-butylphenol), 2,2'-methylene-bis(4-methyl-6-cyclohexylphenol), 2,2'-methylene-bis(4-methyl-6-nonylphenol), octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, and pentaerythritol tetra(3,5-di-tert-butyl-4-hydroxyhydrocinnamate). Co-antioxidants, such as tri(nonylphenyl) phosphite and / or dilauryl thiodipropionate.

[0035] Exemplarily, the compatibilizer is an additive used to impart compatibility by removing the multiphase components of biodegradable polyester, polylactic acid, and starch. The compatibilizer includes, but is not limited to, at least one of polyvinyl acetate (PVAc), isocyanate, polypropylene carbonate, glycidyl methacrylate, ethylene-vinyl alcohol, polyvinyl alcohol (PVA), ethylene-vinyl acetate, or maleic anhydride.

[0036] For example, the nucleating agent is an additive used to supplement or change the crystal morphology of the polymer and to increase the crystallization (solidification) rate when the polymer melt is cooled; the nucleating agent includes, but is not limited to, inorganic compounds (such as calcium carbonate, silicon dioxide, kaolin), low molecular weight organic compounds (such as myristic acid, palmitic acid, stearic acid, behenic acid, monomethyl terephthalate, isophthalic acid), polymers (such as polyethylene glycol, polypropylene glycol, carboxyl-containing polyethylene, acrylic-styrene copolymer), etc.

[0037] For example, the light stabilizer includes at least one of ultraviolet absorbers, ultraviolet shielders, and free radical scavengers; the ultraviolet absorbers include, but are not limited to, benzophenone-based ultraviolet absorbers (such as UV-9, UV-531), benzotriazole-based ultraviolet absorbers (such as UV-326, UV-P, UV-327), and triazine-based ultraviolet absorbers (such as UV-1577, UV-1164). The ultraviolet shielders include, but are not limited to, titanium dioxide, zinc oxide, etc.; the free radical scavengers include, but are not limited to, hindered amine light stabilizers (such as Tinuvin 770, Tinuvin 622, Chimassorb 944), etc.

[0038] In this invention, the hydrolysis-resistant agents include, but are not limited to, isocyanate-based hydrolysis-resistant agents (such as toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, etc.), epoxide-based hydrolysis-resistant agents (3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarbamate, epoxidized soybean oil, epoxidized fatty acid methyl ester, etc.), carbodiimide-based hydrolysis-resistant agents (4,4'-dicyclohexylmethane carbodiimide, phenylenediamine carbodiimide, hexamethylene carbodiimide, polycarbodiimide, etc.), polyols (such as ethylene glycol, 1,4-butanediol, etc.), polyamines (such as ethylenediamine, hexamethylenediamine), and polyol amines (such as diethanolamine, etc.).

[0039] In this invention, the colorant includes, but is not limited to, at least one of CI Pigment Yellow 138, CI Pigment Yellow 147, CI Pigment Red 214, CI Pigment Red 242, and carbon black.

[0040] In this invention, the preparation method of the biodegradable polyester composite material is not limited in too much. It can be prepared by conventional methods, including but not limited to the following methods: mixing polylactic acid, biodegradable polyester, inorganic filler and optional additives, melt extruding and granulating at 150~200°C, cooling and air drying to obtain the biodegradable polyester composite material.

[0041] In a second aspect, the present invention provides a biodegradable mulch film, wherein the biodegradable mulch film is prepared using the biodegradable polyester composite material described in the first aspect.

[0042] Preferably, after the biodegradable mulch film is aged for 24 hours at a temperature of 85°C and a humidity of 85%, the maximum puncture force retention rate is ≥85%.

[0043] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows: The biodegradable polyester composite material provided by the present invention uses a specific type of polylactic acid and biodegradable polyester and inorganic fillers in a specific content to make the membrane material have good resistance to damp heat aging. After aging, it can still maintain a high maximum puncture force value. Furthermore, by using inorganic fillers with specific D98 and loose density, it is beneficial to further improve the resistance to damp heat aging of the membrane material. Detailed Implementation

[0045] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0046] In this invention, the initial melt index of the polylactic acid, i.e., the melt index after boiling in water for 0 hours, is denoted as MI. 0h The melt flow index after boiling in water at 80℃ for 2 hours is denoted as MI. 2h The ratio M of the melt index after boiling in water at 80℃ for 2 hours to the initial melt index. 2h / 0h =MI 2h / MI 0h The specific test method for melt flow index includes: according to ISO 1133-1:2022 standard, the test conditions are 190℃ and 2.16kg.

[0047] In this invention, the D98 test method for the inorganic filler is determined in accordance with GB / T 19077.1-2008 "Particle size analysis by laser diffraction".

[0048] In this invention, the loose density (i.e., bulk density) of the inorganic filler is determined by the Scott volumetric method in GB / T 31057.1-2018 "Test Method for Physical Properties of Particulate Materials".

[0049] Biodegradable polyester PBAT: Kingfa Biotech A400.

[0050] PBSeT: Kingfa Biotech A300.

[0051] The specific types of polylactic acid are shown in Table 1.

[0052] Table 1 The specific types of inorganic packing materials are shown in Table 2.

[0053] Table 2 Antioxidants, light stabilizers, hydrolysis resistant agents, and lubricants are all sourced from commercially available products.

[0054] Examples 1-20 and Comparative Examples 1-5 each provide a biodegradable polyester composite material. The formulations of the biodegradable polyester composite materials are shown in Tables 3-6, by weight. Unless otherwise specified, all values ​​in Tables 3-6 refer to parts by weight. The preparation method of the biodegradable polyester composite material includes: mixing biodegradable polyester, polylactic acid, and optionally antioxidants, light stabilizers, hydrolysis resistant agents, and lubricants to obtain a premix; then mixing the premix with inorganic fillers in a twin-screw extruder and extruding at 180°C to obtain the biodegradable polyester composite material.

[0055] Table 3 Table 4 Table 5 Table 6 The performance tests were conducted by blowing the biodegradable polyester composite materials provided in the examples and comparative examples into films with a thickness of 12±1μm using a blown film machine, and then bagging them using a bag-cutting machine. The specific process was as follows: the blown film temperature was 150℃, and the blown film speed was 20kg / h. The resulting biodegradable films were subjected to the following performance tests.

[0056] (1) Aging resistance: The maximum puncture force of the biodegradable membrane before and after damp heat aging was tested, and the maximum puncture force retention rate was calculated; the maximum puncture force retention rate = maximum puncture force after damp heat aging / maximum puncture force before damp heat aging × 100%; the damp heat aging conditions were as follows: the biodegradable membrane was hung in a constant temperature and humidity chamber with a temperature of 85℃±2℃ and a humidity of 85±5RH% for 24 hours, and then placed at room temperature for 24 hours for testing.

[0057] The test method for the maximum puncture force includes: testing the puncture performance of the film bag using a universal testing machine, according to the GB / T 21302-2007 standard. The film is fixed on the universal testing machine, and a 7mm diameter puncture test needle is used at a speed of 50mm / min. The maximum puncture force is recorded. The average of five test results is taken.

[0058] The specific test results are shown in Table 7.

[0059] Table 7 As shown in Table 7, the biodegradable polyester composite material provided by the present invention is made by compounding specific polylactic acid with biodegradable polyester and inorganic fillers in specific amounts, so that the resulting membrane material has good resistance to damp heat aging and can still maintain a high maximum puncture force value after aging; the maximum puncture force value retention rate of the biodegradable polyester composite material before and after aging is ≥85%.

[0060] As can be seen from Examples 1 and 12-15, the D98 of the inorganic filler within a certain range is beneficial for obtaining a biodegradable polyester composite material with better resistance to humid heat aging.

[0061] As can be seen from Examples 1, 18, and 19, the loose density of the inorganic filler within a specific range is beneficial for obtaining a biodegradable polyester composite material with better resistance to damp heat aging.

[0062] As shown in Examples 1 and 6-11, when the melt index ratio of the polylactic acid before and after boiling is within a specific range, it is beneficial to obtain a biodegradable polyester composite material with better resistance to damp heat aging. As shown in Comparative Examples 1-5, when the melt index ratio of the polylactic acid before and after boiling is not within a specific range, the resulting composite material has poor resistance to damp heat aging.

[0063] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A biodegradable polyester composite material, characterized in that, By weight, the biodegradable polyester composite material comprises 70-95 parts of biodegradable polyester, 2-10 parts of polylactic acid, and 3-20 parts of inorganic filler; the ratio of the melt index of the polylactic acid after boiling in water at 80°C for 2 hours to the initial melt index is 1.1-5.

2. The biodegradable polyester composite material according to claim 1, characterized in that, The ratio of the melt index of the polylactic acid after boiling in water at 80°C for 2 hours to the initial melt index is 1.2~4, more preferably 1.5~3.

3. The biodegradable polyester composite material according to claim 1, characterized in that, The polylactic acid includes copolymers of D-lactic acid and L-lactic acid.

4. The biodegradable polyester composite material according to claim 1, characterized in that, The biodegradable polyester includes aliphatic-aromatic copolyesters; preferably, the aliphatic-aromatic copolyester includes any one or a combination of at least two of polybutylene adipate, polybutylene sebacate, and polybutylene succinate.

5. The biodegradable polyester composite material according to claim 1, characterized in that, The inorganic filler includes any one or a combination of at least two of the following: talc, calcium carbonate, silica, montmorillonite, kaolin, chalk, gypsum, calcium chloride, iron oxide, dolomite, wollastonite, titanium dioxide, silicates, and mica; preferably, any one or a combination of at least two of the following: talc, calcium carbonate, silica, montmorillonite, and kaolin.

6. The biodegradable polyester composite material according to claim 1, characterized in that, The inorganic filler has a D98 ≤ 15 μm, preferably 1~13 μm, more preferably 4~10 μm; preferably, the loose density of the inorganic filler is 0.1~0.9 g / cm³. 3 More preferably, it is 0.2~0.5 g / cm³. 3 .

7. The biodegradable polyester composite material according to claim 1, characterized in that, The biodegradable polyester composite material further includes 0.4 to 8 parts by weight of additives.

8. The biodegradable polyester composite material according to claim 7, characterized in that, The additives include at least one of the following: lubricant, antioxidant, compatibilizer, nucleating agent, colorant, light stabilizer, and hydrolysis resistant agent.

9. A biodegradable mulch film, characterized in that, The biodegradable mulch film is prepared using the biodegradable polyester composite material described in any one of claims 1 to 8.

10. The biodegradable mulch film according to claim 9, characterized in that, The biodegradable mulch film retains a maximum puncture force value of ≥85% after aging for 24 hours at a temperature of 85℃ and a humidity of 85%.

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