Environment-friendly degradable packaging material and preparation method thereof
By synergistically modifying the structure through tannic acid-induced hydrogen bond reconstruction of cellulose and urea flexible crosslinking network, combined with components such as 2,6-dihydroxynaphthalene, the problems of poor mechanical properties, insufficient moisture resistance and processing brittleness of environmentally friendly and biodegradable packaging materials have been solved, achieving high strength, flexibility and stability of the material.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAMEN GAOCAI PACKAGING TECH CO LTD
- Filing Date
- 2026-05-22
- Publication Date
- 2026-06-23
AI Technical Summary
Existing environmentally friendly and biodegradable packaging materials have poor mechanical properties, insufficient moisture resistance, low interfacial compatibility, and are prone to brittleness during processing. Furthermore, traditional modification methods lead to performance degradation.
A synergistic modified structure was formed by tannic acid-induced hydrogen bond reconstruction of cellulose and urea flexible crosslinking network. Combined with components such as 2,6-dihydroxynaphthalene, thermoplastic starch, nanocellulose and epoxidized soybean oil, a multi-synergistic reinforcement system was constructed to improve the interfacial bonding ability and flexibility of the material.
It significantly improves the mechanical properties, moisture resistance, and processing performance of the material, while maintaining good biodegradability, thus achieving high strength, flexibility, and stability.
Smart Images
Figure CN122255696A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of environmentally friendly polymer materials technology, specifically to an environmentally friendly biodegradable packaging material and its preparation method. Background Technology
[0002] With the rapid development of the green packaging and sustainable materials industry, environmentally friendly and biodegradable packaging materials are gradually replacing traditional non-degradable plastics such as polyethylene and polypropylene, and are widely used in food packaging, express packaging, daily necessities packaging, and disposable packaging products. Among them, polylactic acid, thermoplastic starch, and cellulose-based bio-based materials have become important research directions in biodegradable packaging materials due to their wide availability, good biodegradability, and environmental friendliness.
[0003] However, existing environmentally friendly and biodegradable packaging materials still have many problems in practical applications. On the one hand, polylactic acid materials are inherently brittle, with poor impact resistance and folding resistance, and are prone to cracking during processing and use. On the other hand, starch and cellulose-based natural materials have strong hydrophilicity, and are prone to absorbing moisture and swelling in humid environments, leading to a decrease in material mechanical properties, poor dimensional stability, and a shortened service life.
[0004] Currently, existing technologies typically modify biodegradable packaging materials using methods such as plasticizer toughening, inorganic filler reinforcement, or ordinary polymer blending. However, traditional modification methods are mostly simple physical mixing, lacking stable and effective synergistic structures within the material, resulting in limited interfacial bonding and problems such as phase separation, poor processing stability, and later performance degradation. Some modifiers can also affect the degradation performance of the material, leading to a decline in environmental performance and failing to meet the development needs of high-performance environmentally friendly packaging materials.
[0005] Therefore, developing an environmentally friendly and biodegradable packaging material with a synergistic modified structure that can simultaneously improve the material's mechanical properties, moisture resistance, and processing performance, while also taking into account its biodegradability, has significant research and application value. Summary of the Invention
[0006] To overcome the problems of poor mechanical properties, insufficient moisture resistance, low interfacial compatibility, and brittleness during processing in existing environmentally friendly biodegradable packaging materials, this invention aims to provide an environmentally friendly biodegradable packaging material and its preparation method. This invention utilizes tannic acid-induced hydrogen bond reconstruction of cellulose to form a synergistic modified structure with a urea flexible crosslinking network, and combines this with components such as 2,6-dihydroxynaphthalene, thermoplastic starch, nanocellulose, and epoxidized soybean oil to construct a multi-layered synergistic reinforcement system, thereby improving the material's internal interfacial bonding ability and flexibility. The environmentally friendly biodegradable packaging material prepared by this invention exhibits excellent mechanical properties, moisture resistance, and processing performance, while also possessing good environmental degradation properties.
[0007] The objective of this invention can be achieved through the following technical solutions: An environmentally friendly and biodegradable packaging material comprises the following raw materials in parts by weight: 60-120 parts polylactic acid; 10-40 parts synergistic modified structural material; 2-15 parts 2,6-dihydroxynaphthalene; 20-60 parts thermoplastic starch; 5-25 parts nanocellulose; 5-20 parts epoxidized soybean oil; 1-8 parts lubricant; 1-5 parts antioxidant; and 2-12 parts compatibilizer. The synergistic modified structural material is a composite structure formed by the synergistic modification of a tannic acid-induced cellulose hydrogen bond reconstruction structure and a urea flexible crosslinking network.
[0008] Optionally, the synergistic modified structure comprises the following raw materials in parts by weight: 10-40 parts tannic acid; 20-80 parts cellulose; 5-30 parts urea; 5-25 parts glycerol; and 40-150 parts deionized water.
[0009] Optionally, the method for preparing the synergistically modified structure includes the following steps: (1) Add phytic acid and urea to deionized water and mix and stir to obtain a uniform pre-modified solution; (2) Add cellulose to the pre-modified solution to carry out a dispersion reaction, so that phytic acid and cellulose form a synergistic structure to obtain a synergistic modified system; (3) Add glycerol to the synergistic modification system for compounding and adjustment, and then continue to stir and mix to obtain the synergistic modified structure.
[0010] Optionally, the stirring temperature in step (1) is 40-60℃, the stirring time is 1-3h, and the stirring speed is 200-600rpm.
[0011] Optionally, the reaction temperature in step (2) is 50-80℃, the reaction time is 1-4h, and the dispersion stirring speed is 300-1000rpm.
[0012] Optionally, the compounding time in step (3) is 0.5 to 2 hours and the compounding temperature is 30 to 60°C.
[0013] Optionally, the lubricant is a mixture of zinc stearate and ethylene bis-stearamide in a mass ratio of 1:1 to 4:1; the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1 to 3:1; and the compatibilizer is a mixture of maleic anhydride-grafted polylactic acid and epoxidized soybean oil in a mass ratio of 1:1 to 5:2.
[0014] Optionally, a method for preparing a high-strength adhesive ground protection tape includes the following steps: S1, polylactic acid, thermoplastic starch and nanocellulose are added to a high-speed mixing device for premixing to obtain basic blend material; S2, add synergistic modifiers, 2,6-dihydroxynaphthalene, epoxidized soybean oil and compatibilizer to the basic blend material and melt blend to obtain a modified composite system; S3 involves adding lubricants and antioxidants to a modified composite system, followed by extrusion granulation, and then casting or blown film molding to obtain environmentally friendly and biodegradable packaging materials.
[0015] Optionally, the premixing temperature in step S1 is 50–80°C, the premixing time is 10–40 min, and the mixing speed is 300–800 rpm; the melt blending temperature in step S2 is 140–185°C, the blending time is 20–60 min, and the screw speed is 50–300 rpm.
[0016] Optionally, the extrusion temperature in step S3 is 150–190°C, and the casting or blown film forming temperature after granulation is 140–180°C.
[0017] The beneficial effects of this invention are: This invention utilizes tannic acid-induced hydrogen bond remodeling of cellulose and urea's flexible cross-linking network to form a synergistic modified structure. The polyphenolic hydroxyl groups in tannic acid can form multiple hydrogen bonds with cellulose molecular chains, resulting in a dynamically remodeled structure between cellulose segments, thereby improving the material's internal interfacial bonding ability. Simultaneously, urea can form a flexible cross-linking network between cellulose segments, reducing local stress concentration in the polylactic acid system and improving the material's flexibility and crack resistance. This synergistic modification method differs from traditional single plasticization or ordinary blending modification, maintaining good biodegradability while enhancing the material's mechanical properties. This invention is the first to apply 2,6-dihydroxynaphthalene to an environmentally friendly biodegradable packaging material system. Utilizing its rigid aromatic ring structure and dihydroxyl active sites, it enhances the material's internal hydrogen bonding and intermolecular forces, effectively improving the material's moisture resistance, tear resistance, and thermal stability. Furthermore, it forms multiple interfacial reinforcement effects with the synergistic modified structure, thus giving the material high strength, good flexibility, and stable processing performance. Attached Figure Description
[0018] The invention will now be further described with reference to the accompanying drawings.
[0019] Figure 1 The infrared spectra of cellulose composites synergistically modified with tannic acid / urea are shown in comparison. Detailed Implementation
[0020] The present invention will be further described below with reference to specific embodiments. However, the present invention is not limited to the following embodiments. Equivalent adjustments made without departing from the spirit and essence of the present invention should also be considered to fall within the protection scope of the present invention.
[0021] Example 1: The purpose of this example is to obtain an environmentally friendly and biodegradable packaging material with basic film-forming properties and good biodegradability.
[0022] S1, 10 parts of tannic acid and 5 parts of urea were added to 40 parts of deionized water and stirred at 200 rpm for 1 h at 40 °C to obtain a homogeneous pre-modified solution; then 20 parts of cellulose were added to the pre-modified solution and dispersed at 300 rpm for 1 h at 50 °C to obtain a synergistic modification system; then 5 parts of glycerol were added to the synergistic modification system and stirred at 30 °C for 0.5 h to obtain the synergistic modified structure. S2, 60 parts of polylactic acid, 20 parts of thermoplastic starch and 5 parts of nanocellulose are added to a high-speed mixer and premixed at 300 rpm for 10 min at 50°C to obtain a basic blend material; then 10 parts of synergistic modifier, 2 parts of 2,6-dihydroxynaphthalene, 5 parts of epoxidized soybean oil and 2 parts of compatibilizer are added to the basic blend material and melt-blended at 50 rpm for 20 min at 140°C to obtain a modified composite system; S3, add 1 part lubricant and 1 part antioxidant to the modified composite system, extrude and granulate at 150°C, and then cast at 140°C to obtain an environmentally friendly and biodegradable packaging material.
[0023] Example 2: The purpose of this example is to obtain an environmentally friendly and biodegradable packaging material with optimal overall mechanical properties, flexibility, and moisture resistance.
[0024] S1, 25 parts of tannic acid and 18 parts of urea were added to 95 parts of deionized water and stirred at 400 rpm for 2 h at 50 °C to obtain a homogeneous pre-modified solution; then 50 parts of cellulose were added to the pre-modified solution and dispersed at 600 rpm for 2.5 h at 65 °C to obtain a synergistic modification system; then 15 parts of glycerol were added to the synergistic modification system and stirred at 45 °C for 1 h to obtain a synergistic modified structure. Figure 1 The infrared spectrum comparison shows that the modified synergistic modified structure has a peak value of 3382 cm⁻¹. -1 The -OH absorption peak at 1724 cm⁻¹ broadened significantly and red-shifted, indicating a strong hydrogen bond formation between tannic acid, urea, and cellulose; -1 and 1601cm -1The newly added absorption peaks at 1154 cm⁻¹ correspond to the C=O vibration and the aromatic ring skeleton vibration, respectively, indicating that tannic acid and urea have been successfully introduced into the cellulose system. -1 and 1098cm -1 The enhanced absorption peaks of COC and CO indicate that the interaction between cellulose molecular chains is enhanced and a synergistic modified structure is formed; tannic acid and urea have successfully achieved synergistic modification of cellulose. S2, 90 parts of polylactic acid, 40 parts of thermoplastic starch and 15 parts of nanocellulose were added to a high-speed mixer and premixed at 550 rpm for 25 min at 65°C to obtain a basic blend material; then 25 parts of synergistic modifier, 8 parts of 2,6-dihydroxynaphthalene, 12 parts of epoxidized soybean oil and 7 parts of compatibilizer were added to the basic blend material and melt-blended at 180 rpm for 40 min at 165°C to obtain a modified composite system; S3, add 4 parts lubricant and 3 parts antioxidant to the modified composite system, extrude and granulate at 175°C, and then blown into a film at 160°C to obtain an environmentally friendly and biodegradable packaging material.
[0025] Example 3: The purpose of this example is to obtain an environmentally friendly and biodegradable packaging material with high strength, heat resistance and structural stability.
[0026] S1, 40 parts of tannic acid and 30 parts of urea were added to 150 parts of deionized water and stirred at 600 rpm for 3 hours at 60°C to obtain a homogeneous pre-modified solution; then 80 parts of cellulose were added to the pre-modified solution and dispersed at 1000 rpm for 4 hours at 80°C to obtain a synergistic modification system; then 25 parts of glycerol were added to the synergistic modification system and stirred at 60°C for another 2 hours to obtain a synergistic modified structure. S2, 120 parts of polylactic acid, 60 parts of thermoplastic starch and 25 parts of nanocellulose were added to a high-speed mixer and premixed at 800 rpm for 40 min at 80°C to obtain a basic blend material; then 40 parts of synergistic modifier, 15 parts of 2,6-dihydroxynaphthalene, 20 parts of epoxidized soybean oil and 12 parts of compatibilizer were added to the basic blend material and melt-blended at 300 rpm for 60 min at 185°C to obtain a modified composite system; S3, add 8 parts of lubricant and 5 parts of antioxidant to the modified composite system, extrude and granulate at 190°C, and then cast at 180°C to obtain an environmentally friendly and biodegradable packaging material.
[0027] Comparative Example 1: The purpose of this comparative example is to verify the effect of tannic acid hydrogen bond reconstruction modification alone on the performance of environmentally friendly and biodegradable packaging materials.
[0028] S1, 25 parts of tannic acid were added to 95 parts of deionized water and stirred at 400 rpm for 2 h at 50 °C to obtain a pre-modified solution; then 50 parts of cellulose were added to the pre-modified solution and dispersed at 600 rpm for 2.5 h at 65 °C to obtain a single-modified system; then 15 parts of glycerol were added to the single-modified system and stirred at 45 °C for 1 h to obtain a single-modified structure. S2, 90 parts of polylactic acid, 40 parts of thermoplastic starch and 15 parts of nanocellulose were added to a high-speed mixer and premixed at 550 rpm for 25 min at 65°C to obtain a basic blend material; then 25 parts of a single modified structural agent, 8 parts of 2,6-dihydroxynaphthalene, 12 parts of epoxidized soybean oil and 7 parts of compatibilizer were added to the basic blend material and melt-blended at 180 rpm for 40 min at 165°C to obtain a modified composite system; S3, add 4 parts lubricant and 3 parts antioxidant to the modified composite system, extrude and granulate at 175°C, and then blown into a film at 160°C to obtain an environmentally friendly and biodegradable packaging material.
[0029] Comparative Example 2: The purpose of this comparative example is to verify the effect of using only urea flexible crosslinking modification on the performance of environmentally friendly and biodegradable packaging materials.
[0030] S1, 18 parts of urea were added to 95 parts of deionized water and stirred at 400 rpm for 2 hours at 50°C to obtain a pre-modified solution; then 50 parts of cellulose were added to the pre-modified solution and dispersed at 600 rpm for 2.5 hours at 65°C to obtain a single-modified system; then 15 parts of glycerol were added to the single-modified system and stirred at 45°C for 1 hour to obtain a single-modified structure. S2, 90 parts of polylactic acid, 40 parts of thermoplastic starch and 15 parts of nanocellulose were added to a high-speed mixer and premixed at 550 rpm for 25 min at 65°C to obtain a basic blend material; then 25 parts of a single modified structural agent, 8 parts of 2,6-dihydroxynaphthalene, 12 parts of epoxidized soybean oil and 7 parts of compatibilizer were added to the basic blend material and melt-blended at 180 rpm for 40 min at 165°C to obtain a modified composite system; S3, add 4 parts lubricant and 3 parts antioxidant to the modified composite system, extrude and granulate at 175°C, and then blown into a film at 160°C to obtain an environmentally friendly and biodegradable packaging material.
[0031] Comparative Example 3: The purpose of this comparative example is to verify the effect of 2,6-dihydroxynaphthalene organic small molecules on the performance of environmentally friendly and biodegradable packaging materials.
[0032] S1, 25 parts of tannic acid and 18 parts of urea were added to 95 parts of deionized water and stirred at 400 rpm for 2 h at 50 °C to obtain a homogeneous pre-modified solution; then 50 parts of cellulose were added to the pre-modified solution and dispersed at 600 rpm for 2.5 h at 65 °C to obtain a synergistic modification system; then 15 parts of glycerol were added to the synergistic modification system and stirred at 45 °C for 1 h to obtain a synergistic modified structure. S2, 90 parts of polylactic acid, 40 parts of thermoplastic starch and 15 parts of nanocellulose were added to a high-speed mixer and premixed at 550 rpm for 25 min at 65°C to obtain a basic blend material; then 25 parts of synergistic modifier, 12 parts of epoxidized soybean oil and 7 parts of compatibilizer were added to the basic blend material and melt-blended at 180 rpm for 40 min at 165°C to obtain a modified composite system; S3, add 4 parts lubricant and 3 parts antioxidant to the modified composite system, extrude and granulate at 175°C, and then blown into a film at 160°C to obtain an environmentally friendly and biodegradable packaging material.
[0033] Performance testing: 1. Tensile property test The environmentally friendly biodegradable packaging materials prepared in the examples and comparative examples were cut into standard dumbbell-shaped specimens with a thickness of 0.20–0.30 mm. After being placed in an environment with a temperature of 23°C and a relative humidity of 50% for 24 hours, the specimens were tested. Tensile properties were tested using an electronic universal testing machine with a clamp spacing of 50 mm and a tensile speed of 50 mm / min. The tensile strength and elongation at break of the material were recorded during the test. Each group of samples was tested in parallel 5 times, and the average value was taken as the final test result.
[0034] 2. Moisture resistance stability test The environmentally friendly biodegradable packaging materials prepared in the examples and comparative examples were cut into 100mm×100mm film samples, and the initial mass and initial tensile strength were measured. The samples were then placed in a constant temperature and humidity chamber at 40℃ and 90% relative humidity for 72h. After the treatment, the samples were taken out, the surface moisture was wiped off, and the sample mass and tensile strength were measured again. The moisture absorption mass change rate and tensile strength retention rate of the material were calculated to evaluate the moisture resistance stability of the material in a high humidity environment.
[0035] 3. Tear resistance test The environmentally friendly biodegradable packaging materials prepared in the examples and comparative examples were processed into film samples of uniform thickness and cut into test strips 150 mm long and 15 mm wide. A 20 mm long cut was made in the middle of the strips, and then a continuous tensile test was performed using a film tear strength tester. The tensile speed was set to 100 mm / min, and the maximum force required for the sample to tear continuously was recorded. Each group of samples was tested in parallel 5 times, and the average value was taken as the tear resistance result of the material.
[0036] 4. Thermal deformation stability test The environmentally friendly biodegradable packaging materials prepared in the examples and comparative examples were cut into sheet samples with a size of 80mm×80mm, and their initial length and width were measured. The samples were then placed in an 80℃ constant temperature forced-air drying oven for 2 hours. After the treatment, the samples were taken out and cooled to room temperature, and their length and width changes were measured. At the same time, it was observed whether curling, bubbling or obvious deformation occurred on the sample surface. The thermal deformation stability of the material was evaluated based on the dimensional change rate.
[0037] Table 1 Performance test results of the examples and comparative examples Group Tensile strength (MPa) Elongation at break (%) Tear strength (kN / m) Tensile strength retention rate (%) Dimensional change rate due to heat distortion (%) Example 1 32.6 238.4 41.2 81.5 4.8 Example 2 41.8 356.7 58.9 92.4 2.1 Example 3 38.5 301.6 52.4 88.7 2.9 Comparative Example 1 25.4 185.3 31.6 70.2 7.5 Comparative Example 2 27.1 201.8 34.5 73.8 6.8 Comparative Example 3 30.8 226.7 39.4 79.1 5.3 According to Table 1, the environmentally friendly biodegradable packaging materials prepared in Examples 1-3 are significantly better than those in Comparative Examples 1-3 in terms of tensile strength, elongation at break, tear strength, moisture resistance, and heat distortion stability. This indicates that the tannic acid-induced cellulose hydrogen bond reconstruction structure and the urea flexible crosslinking network synergistic modification system constructed in this invention can effectively improve the comprehensive performance of the material.
[0038] Among them, Example 2 exhibited the best overall performance, with a tensile strength of 41.8 MPa, an elongation at break of 356.7%, a tear strength of 58.9 kN / m, a tensile strength retention rate of 92.4%, and a heat distortion dimensional change rate of only 2.1%. This is because the proportions of each component and the reaction conditions in Example 2 were within an optimal range. Tannic acid was able to form a relatively stable multi-hydrogen bond structure with cellulose, while the flexible cross-linked network formed by urea could effectively alleviate the stress concentration phenomenon inside the polylactic acid system, thereby improving the flexibility and tear resistance of the material. In addition, the rigid aromatic ring structure of 2,6-dihydroxynaphthalene further enhanced the interfacial forces inside the material, enabling the material to maintain good structural stability under high humidity and heat environments.
[0039] Although Example 1 possesses certain comprehensive properties, its tensile strength, elongation at break, and moisture resistance are relatively low due to the low addition of synergistic modified structural material and 2,6-dihydroxynaphthalene, resulting in insufficient formation of the synergistic structure within the material. In Example 3, although the content of synergistic modified structural material and functional components is further increased, the higher system viscosity easily leads to a decrease in the uniformity of local structural dispersion, causing the material's flexibility to be slightly lower than that of Example 2.
[0040] Comparative Example 1 uses only a tannic acid-based modification system, lacking the flexible cross-linked network structure of urea, resulting in insufficient internal flexible buffering capacity and a significant decrease in its elongation at break and tear resistance. Comparative Example 2 also uses only a urea-based modification system. Due to the lack of a tannic acid-induced multiple hydrogen bond reconstruction structure, the interfacial bonding capacity within the material is weak, thus significantly reducing its tensile strength and moisture stability. Comparative Example 3 does not contain 2,6-dihydroxynaphthalene, resulting in insufficient rigid interfacial reinforcement within the material, thereby lower thermal stability and tear resistance compared to Example 2.
[0041] In summary, this invention achieves a synergistic modified structure by inducing hydrogen bond reconstruction of cellulose with tannic acid and forming a flexible crosslinking network with urea, and by constructing a multi-interface reinforcement system with 2,6-dihydroxynaphthalene. This effectively improves the mechanical properties, flexibility, moisture resistance, and thermal stability of environmentally friendly and biodegradable packaging materials, giving the materials excellent comprehensive application performance.
Claims
1. An environmentally friendly and biodegradable packaging material, characterized in that, The environmentally friendly and biodegradable packaging material comprises the following raw materials in parts by weight: 60-120 parts polylactic acid; 10-40 parts synergistic modified structural material; 2-15 parts 2,6-dihydroxynaphthalene; 20-60 parts thermoplastic starch; 5-25 parts nanocellulose; 5-20 parts epoxidized soybean oil; 1-8 parts lubricant; 1-5 parts antioxidant; and 2-12 parts compatibilizer. The synergistic modified structural material is a composite structure formed by the synergistic modification of the cellulose hydrogen bond reconstruction structure induced by tannic acid and the flexible cross-linking network of urea.
2. The environmentally friendly biodegradable packaging material according to claim 1, characterized in that, The synergistic modified structure comprises the following raw materials in parts by weight: 10-40 parts tannic acid; 20-80 parts cellulose; 5-30 parts urea; 5-25 parts glycerol; and 40-150 parts deionized water.
3. An environmentally friendly biodegradable packaging material according to claim 1 or 2, characterized in that, The method for preparing the synergistic modified structure includes the following steps: (1) Add phytic acid and urea to deionized water and mix and stir to obtain a uniform pre-modified solution; (2) Add cellulose to the pre-modified solution to carry out a dispersion reaction, so that phytic acid and cellulose form a synergistic structure to obtain a synergistic modified system; (3) Add glycerol to the synergistic modification system for compounding and adjustment, and then continue to stir and mix to obtain the synergistic modified structure.
4. The environmentally friendly biodegradable packaging material according to claim 3, characterized in that, The stirring temperature in step (1) is 40-60℃, the stirring time is 1-3h, and the stirring speed is 200-600rpm.
5. The environmentally friendly biodegradable packaging material according to claim 3, characterized in that, The reaction temperature in step (2) is 50-80℃, the reaction time is 1-4h, and the dispersion stirring speed is 300-1000rpm.
6. The environmentally friendly biodegradable packaging material according to claim 3, characterized in that, The compounding time in step (3) is 0.5 to 2 hours, and the compounding temperature is 30 to 60°C.
7. The environmentally friendly biodegradable packaging material according to claim 1, characterized in that, The lubricant is a mixture of zinc stearate and ethylene bis-stearamide in a mass ratio of 1:1 to 4:1; the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1 to 3:1; and the compatibilizer is a mixture of maleic anhydride-grafted polylactic acid and epoxidized soybean oil in a mass ratio of 1:1 to 5:
2.
8. A method for preparing a high-strength adhesive ground protection tape, characterized in that, The preparation method includes the following steps: S1, polylactic acid, thermoplastic starch and nanocellulose are added to a high-speed mixing device for premixing to obtain basic blend material; S2, add synergistic modifiers, 2,6-dihydroxynaphthalene, epoxidized soybean oil and compatibilizer to the basic blend material and melt blend to obtain a modified composite system; S3 involves adding lubricants and antioxidants to a modified composite system, followed by extrusion granulation, and then casting or blown film molding to obtain environmentally friendly and biodegradable packaging materials.
9. The method for preparing an environmentally friendly biodegradable packaging material according to claim 8, characterized in that, In step S1, the premixing temperature is 50–80°C, the premixing time is 10–40 min, and the mixing speed is 300–800 rpm; in step S2, the melt blending temperature is 140–185°C, the blending time is 20–60 min, and the screw speed is 50–300 rpm.
10. The method for preparing an environmentally friendly biodegradable packaging material according to claim 8, characterized in that, The extrusion temperature in step S3 is 150-190°C, and the casting or blown film forming temperature after granulation is 140-180°C.