Degradable express bag material and preparation method thereof

Abstract

The invention relates to the technical field of express bags, and discloses a degradable express bag material and a preparation method thereof, the degradable express bag material comprises the following components by weight: 20-55 parts of thermoplastic starch, 2-10 parts of plant fiber, 5-15 parts of modified starch, 10-25 parts of a mixed biodegradable material, 15-20 parts of paraformaldehyde (PFA), 5-15 parts of N-methyl pyrrolidone, and 20-45 parts of low density polyethylene, the degradable plastic is prepared from the following components in parts by weight: 10-30 parts of polylactic acid, 2-10 parts of polycaprolactone, 0.2-0.6 part of a photodegradation agent, 6-20 parts of filler master batch, 0.2-1.8 parts of a lubricant and 4-12 parts of a phase solvent. According to the degradable express bag material, various bio-based and degradable components such as the thermoplastic starch, the plant fibers, the polylactic acid and the polycaprolactone are adopted, the components can be rapidly decomposed in the natural environment, and pollution of a traditional plastic express bag to the environment is remarkably reduced. Meanwhile, the photodegradation agent and the photosensitizer are added, so that the degradation process of the material can be accelerated under the illumination condition, and the environmental friendliness of the material is further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of express bags, and in particular, relates to a degradable express bag material and a preparation method thereof. Background Art

[0002] In the express packaging industry, the traditionally widely used plastic express bags are favored due to their low cost and convenient processing. However, with the enhancement of global environmental awareness and the popularization of the concept of sustainable development, the non-degradability of traditional plastic express bags and their long-term pollution to the environment have become increasingly prominent.

[0003] Traditional plastic courier bags are difficult to degrade in the natural environment. The "white pollution" formed after a large number of uses has caused serious damage to the soil, water sources and ecosystems. These plastic wastes have accumulated in the environment for a long time, which not only affects the beauty of the landscape, but also poses a potential threat to human health through the food chain. Secondly, the production of traditional plastics depends on fossil resources such as petroleum, which are limited and non-renewable. The large-scale production and use of plastic courier bags has aggravated resource consumption and is not conducive to sustainable development.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0006] A degradable express bag material, comprising the following components calculated by weight: 20-55 parts of thermoplastic starch, 2-10 parts of plant fiber, 5-15 parts of modified starch, 10-25 parts of mixed biodegradable materials, 15-20 parts of paraformaldehyde (PFA), 5-15 parts of N-methylpyrrolidone, 20-45 parts of low-density polyethylene, 10-30 parts of polylactic acid, 2-10 parts of polycaprolactone, 0.2 -0.6 parts, filler masterbatch 6-20 parts, lubricant 0.2-1.8 parts, compatibilizer 4-12 parts, photosensitizer 2-10 parts; the filler masterbatch includes the following components calculated by weight: calcium carbonate 15-40 parts, talc 10-30 parts, camellia peel powder 5-15 parts, titanium dioxide 5-10 parts, modified silicon dioxide 10-15 parts, low-density polyethylene 8-18 parts, silane coupling agent 2-8 parts.

[0007] As a preferred embodiment of the present invention, the particle size of the titanium dioxide is 5-10 microns; the particle size of the modified silicon dioxide is 1-5 microns.

[0008] As a preferred embodiment of the present invention, the modified silicon dioxide is prepared by the following steps: adding silicon dioxide powder to molten zinc chloride, heating at 350-400°C for 70-90 minutes; filtering while hot, rinsing the filter cake with deionized water, drying and sieving out particles with a particle size in the range of 1-5 microns to obtain modified silicon dioxide.

[0009] As a preferred embodiment of the present invention, the photodegradation agent is iron stearate; the lubricant is stearic acid; and the compatibilizer is low-density polyethylene grafted with maleic anhydride.

[0010] As a preferred embodiment of the present invention, the photosensitizer is one or more of benzophenone, p-benzoquinone, and benzanthraquinone alcohol.

[0011] As a preferred embodiment of the present invention, the preparation method of the modified starch is: starch, a modifier, and a coupling agent are stirred uniformly in a high-speed mixer at 90-110° C., then propylene glycol is added, stirred uniformly, and then granulated by twin-screw extrusion to obtain the modified starch.

[0012] As a preferred embodiment of the present invention, the starch includes but is not limited to corn starch and cassava starch; the modifier is tartaric acid; and the coupling agent is a titanate coupling agent.

[0013] As a preferred embodiment of the present invention, the plant fiber includes one or more of bamboo fiber, cotton fiber, straw, coconut fiber and corn stalk.

[0014] As a preferred embodiment of the present invention, the mixed biodegradable material includes one or more of PBAT, PPC and PLA.

[0015] A method for preparing a degradable courier bag material comprises the following steps:

[0016] The first step: weighing the formula amount of calcium carbonate, talcum powder, camellia peel powder, and low-density polyethylene, mixing them in a high-speed blender, and extruding and granulating them in an extruder to prepare a filling masterbatch;

[0017] Step 2: Add silicon dioxide powder to molten zinc chloride, heat at 350-400°C for 70-90 minutes; filter while hot, rinse the filter cake with deionized water, dry and sieve out particles with a particle size of 1-5 microns to obtain modified silicon dioxide;

[0018] Step 3: Mix starch, modifier and coupling agent in a high-speed mixer at 90-110°C, add glycerol, mix well, and granulate by twin-screw extrusion to obtain modified starch;

[0019] Step 4: Weigh thermoplastic starch, plant fiber, modified starch, mixed biodegradable material, paraformaldehyde (PFA), N-methylpyrrolidone 5, low-density polyethylene, polylactic acid, polycaprolactone, photodegradation agent, filler masterbatch, lubricant, compatibilizer, photosensitizer and filler masterbatch according to the formula components, put the component materials into a mixer and mix them evenly; put the mixed materials into an extruder at a temperature of 155-170°C, extrude, cool and granulate;

[0020] Step 5: Add the particles obtained in step 4 into the film blowing machine, raise the temperature to 140-180℃ for film blowing, and add them into the bag making machine after cooling to make degradable express bag materials.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The degradable courier bag material of the present invention adopts a variety of bio-based and degradable components, such as thermoplastic starch, plant fiber, polylactic acid, polycaprolactone, etc. These components can be decomposed quickly in the natural environment, significantly reducing the pollution of traditional plastic courier bags to the environment. At the same time, the addition of photodegradation agents and photosensitizers can accelerate the degradation process of the material under light conditions, further improving its environmental friendliness.

[0023] 2. The material of the present invention has excellent physical properties while maintaining degradability. The composite use of thermoplastic starch, modified starch, mixed biodegradable materials and low-density polyethylene improves the strength, toughness and processing performance of the material, so that it can meet the actual use requirements of express bags. In addition, the addition of filler masterbatch further enhances the performance stability of the material.

[0024] 3. The raw materials of the present invention are widely available and renewable. For example, starch can be extracted from crops such as corn and cassava, and plant fibers come from natural resources such as bamboo, cotton, and straw. This wide range of raw material sources not only reduces production costs, but also helps promote the resource utilization of agricultural waste and promote the development of a circular economy.

[0025] 4. The addition of lubricants, compatibilizers and other additives in the material of the present invention effectively improves the processing performance of the material, making it smoother during the production process, reducing energy consumption and production costs. At the same time, these additives also help to improve the uniformity and stability of the material and ensure the quality of the final product.

[0026] 5. The present invention can adjust the type and amount of photodegradants and photosensitizers according to different usage environments and degradation requirements; or select appropriate types and proportions of plant fibers based on cost considerations. This flexible customization capability makes the material have broad application prospects in the field of express packaging. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments are described clearly and completely, and the following embodiments are used to illustrate the present invention.

[0028] A degradable express bag material, comprising the following components calculated by weight: 20-55 parts of thermoplastic starch, 2-10 parts of plant fiber, 5-15 parts of modified starch, 10-25 parts of mixed biodegradable materials, 15-20 parts of paraformaldehyde (PFA), 5-15 parts of N-methylpyrrolidone, 20-45 parts of low-density polyethylene, 10-30 parts of polylactic acid, 2-10 parts of polycaprolactone, 0.2 -0.6 parts, filler masterbatch 6-20 parts, lubricant 0.2-1.8 parts, compatibilizer 4-12 parts, photosensitizer 2-10 parts; the filler masterbatch includes the following components calculated by weight: calcium carbonate 15-40 parts, talc 10-30 parts, camellia peel powder 5-15 parts, titanium dioxide 5-10 parts, modified silicon dioxide 10-15 parts, low-density polyethylene 8-18 parts, silane coupling agent 2-8 parts.

[0029] The particle size of the titanium dioxide is 5-10 microns; the particle size of the modified silicon dioxide is 1-5 microns. The modified silicon dioxide is prepared by the following steps: adding silicon dioxide powder to molten zinc chloride, heating at 350-400°C for 70-90 minutes; filtering while hot, rinsing the filter cake with deionized water, and sieving out particles with a particle size of 1-5 microns after drying to obtain modified silicon dioxide.

[0030] The photodegradation agent is iron stearate; the lubricant is stearic acid; the compatibilizer is low-density polyethylene grafted maleic anhydride. The photosensitizer is one or more of benzophenone, p-benzoquinone, and benzanthraquinone alcohol. The mixed biodegradable material includes one or more of PBAT, PPC, and PLA.

[0031] The preparation method of the modified starch is as follows: starch, a modifier and a coupling agent are mixed evenly at 90-110° C. in a high-speed mixer, propylene glycol is added, mixed evenly, and then granulated by twin-screw extrusion to obtain the modified starch. The starch includes but is not limited to corn starch and cassava starch; the modifier is tartaric acid; and the coupling agent is a titanate coupling agent. The plant fiber includes one or more of bamboo fiber, cotton fiber, straw, coconut fiber and corn stalk.

[0032] Embodiment 1

[0033] A degradable express bag material comprises the following components calculated by weight: 55 parts of thermoplastic starch, 10 parts of plant fiber, 15 parts of modified starch, 25 parts of mixed biodegradable materials, 20 parts of paraformaldehyde (PFA), 15 parts of N-methylpyrrolidone, 45 parts of low-density polyethylene, 30 parts of polylactic acid, 10 parts of polycaprolactone, 0.6 parts of photodegradation agent, 20 parts of filler masterbatch, 1.8 parts of lubricant, 12 parts of compatibilizing agent, and 10 parts of photosensitizer; the filler masterbatch comprises the following components calculated by weight: 40 parts of calcium carbonate, 30 parts of talc, 15 parts of camellia peel powder, 10 parts of titanium dioxide, 15 parts of modified silicon dioxide, 18 parts of low-density polyethylene, and 8 parts of silane coupling agent.

[0034] A method for preparing a degradable courier bag material comprises the following steps:

[0035] The first step: weighing the formula amount of calcium carbonate, talcum powder, camellia peel powder, and low-density polyethylene, mixing them in a high-speed blender, and extruding and granulating them in an extruder to prepare a filling masterbatch;

[0036] Step 2: Add silicon dioxide powder to molten zinc chloride, heat at 350-400°C for 70-90 minutes; filter while hot, rinse the filter cake with deionized water, dry and sieve out particles with a particle size of 1-5 microns to obtain modified silicon dioxide;

[0037] Step 3: Mix starch, modifier and coupling agent in a high-speed mixer at 90-110°C, add glycerol, mix well, and granulate by twin-screw extrusion to obtain modified starch;

[0038] Step 4: Weigh thermoplastic starch, plant fiber, modified starch, mixed biodegradable material, paraformaldehyde (PFA), N-methylpyrrolidone 5, low-density polyethylene, polylactic acid, polycaprolactone, photodegradation agent, filler masterbatch, lubricant, compatibilizer, photosensitizer and filler masterbatch according to the formula components, put the component materials into a mixer and mix them evenly; put the mixed materials into an extruder at a temperature of 155-170°C, extrude, cool and granulate;

[0039] Step 5: Add the particles obtained in step 4 into the film blowing machine, raise the temperature to 140-180℃ for film blowing, and add them into the bag making machine after cooling to make degradable express bag materials.

[0040] Embodiment 2

[0041] A degradable express bag material comprises the following components calculated by weight: 20 parts of thermoplastic starch, 2 parts of plant fiber, 5 parts of modified starch, 10 parts of mixed biodegradable materials, 15 parts of paraformaldehyde (PFA), 5 parts of N-methylpyrrolidone, 20 parts of low-density polyethylene, 10 parts of polylactic acid, 2 parts of polycaprolactone, 0.2 parts of photodegradation agent, 6 parts of filler masterbatch, 0.2 parts of lubricant, 4 parts of compatibilizer, and 2 parts of photosensitizer; the filler masterbatch comprises the following components calculated by weight: 15 parts of calcium carbonate, 10 parts of talc, 5 parts of camellia peel powder, 5 parts of titanium dioxide, 10 parts of modified silicon dioxide, 8 parts of low-density polyethylene, and 2 parts of silane coupling agent.

[0042] A method for preparing a degradable courier bag material comprises the following steps:

[0043] The first step: weighing the formula amount of calcium carbonate, talcum powder, camellia peel powder, and low-density polyethylene, mixing them in a high-speed blender, and extruding and granulating them in an extruder to prepare a filling masterbatch;

[0044] Step 2: Add silicon dioxide powder to molten zinc chloride, heat at 350-400°C for 70-90 minutes; filter while hot, rinse the filter cake with deionized water, dry and sieve out particles with a particle size of 1-5 microns to obtain modified silicon dioxide;

[0045] Step 3: Mix starch, modifier and coupling agent in a high-speed mixer at 90-110°C, add glycerol, mix well, and granulate by twin-screw extrusion to obtain modified starch;

[0046] Step 4: Weigh thermoplastic starch, plant fiber, modified starch, mixed biodegradable material, paraformaldehyde (PFA), N-methylpyrrolidone 5, low-density polyethylene, polylactic acid, polycaprolactone, photodegradation agent, filler masterbatch, lubricant, compatibilizer, photosensitizer and filler masterbatch according to the formula components, put the component materials into a mixer and mix them evenly; put the mixed materials into an extruder at a temperature of 155-170°C, extrude, cool and granulate;

[0047] Step 5: Add the particles obtained in step 4 into the film blowing machine, raise the temperature to 140-180℃ for film blowing, and add them into the bag making machine after cooling to make degradable express bag materials.

[0048] Embodiment 3

[0049] A degradable express bag material comprises the following components calculated by weight: 20 parts of thermoplastic starch, 10 parts of plant fiber, 5 parts of modified starch, 25 parts of mixed biodegradable materials, 15 parts of paraformaldehyde (PFA), 15 parts of N-methylpyrrolidone, 20 parts of low-density polyethylene, 30 parts of polylactic acid, 2 parts of polycaprolactone, 0.6 parts of photodegradation agent, 6 parts of filler masterbatch, 1.8 parts of lubricant, 4 parts of compatibilizing agent, and 10 parts of photosensitizer; the filler masterbatch comprises the following components calculated by weight: 15 parts of calcium carbonate, 30 parts of talc, 5 parts of camellia peel powder, 10 parts of titanium dioxide, 10 parts of modified silicon dioxide, 18 parts of low-density polyethylene, and 2 parts of silane coupling agent.

[0050] A method for preparing a degradable courier bag material comprises the following steps:

[0051] The first step: weighing the formula amount of calcium carbonate, talcum powder, camellia peel powder, and low-density polyethylene, mixing them in a high-speed blender, and extruding and granulating them in an extruder to prepare a filling masterbatch;

[0052] Step 2: Add silicon dioxide powder to molten zinc chloride, heat at 350-400°C for 70-90 minutes; filter while hot, rinse the filter cake with deionized water, dry and sieve out particles with a particle size of 1-5 microns to obtain modified silicon dioxide;

[0053] Step 3: Mix starch, modifier and coupling agent in a high-speed mixer at 90-110°C, add glycerol, mix well, and granulate by twin-screw extrusion to obtain modified starch;

[0054] Step 4: Weigh thermoplastic starch, plant fiber, modified starch, mixed biodegradable material, paraformaldehyde (PFA), N-methylpyrrolidone 5, low-density polyethylene, polylactic acid, polycaprolactone, photodegradation agent, filler masterbatch, lubricant, compatibilizer, photosensitizer and filler masterbatch according to the formula components, put the component materials into a mixer and mix them evenly; put the mixed materials into an extruder at a temperature of 155-170°C, extrude, cool and granulate;

[0055] Step 5: Add the particles obtained in step 4 into the film blowing machine, raise the temperature to 140-180℃ for film blowing, and add them into the bag making machine after cooling to make degradable express bag materials.

[0056] Embodiment 4

[0057] A degradable express bag material comprises the following components calculated by weight: 30 parts of thermoplastic starch, 5 parts of plant fiber, 7 parts of modified starch, 11 parts of mixed biodegradable materials, 15 parts of paraformaldehyde (PFA), 8 parts of N-methylpyrrolidone, 30 parts of low-density polyethylene, 15 parts of polylactic acid, 8 parts of polycaprolactone, 0.4 parts of photodegradation agent, 10 parts of filler masterbatch, 1.0 parts of lubricant, 6 parts of compatibilizing agent, and 7 parts of photosensitizer; the filler masterbatch comprises the following components calculated by weight: 20 parts of calcium carbonate, 15 parts of talc, 10 parts of camellia peel powder, 6 parts of titanium dioxide, 11 parts of modified silicon dioxide, 9 parts of low-density polyethylene, and 5 parts of silane coupling agent.

[0058] A method for preparing a degradable courier bag material comprises the following steps:

[0059] The first step: weighing the formula amount of calcium carbonate, talcum powder, camellia peel powder, and low-density polyethylene, mixing them in a high-speed blender, and extruding and granulating them in an extruder to prepare a filling masterbatch;

[0060] Step 2: Add silicon dioxide powder to molten zinc chloride, heat at 350-400°C for 70-90 minutes; filter while hot, rinse the filter cake with deionized water, dry and sieve out particles with a particle size of 1-5 microns to obtain modified silicon dioxide;

[0061] Step 3: Mix starch, modifier and coupling agent in a high-speed mixer at 90-110°C, add glycerol, mix well, and granulate by twin-screw extrusion to obtain modified starch;

[0062] Step 4: Weigh thermoplastic starch, plant fiber, modified starch, mixed biodegradable material, paraformaldehyde (PFA), N-methylpyrrolidone 5, low-density polyethylene, polylactic acid, polycaprolactone, photodegradation agent, filler masterbatch, lubricant, compatibilizer, photosensitizer and filler masterbatch according to the formula components, put the component materials into a mixer and mix them evenly; put the mixed materials into an extruder at a temperature of 155-170°C, extrude, cool and granulate;

[0063] Step 5: Add the particles obtained in step 4 into the film blowing machine, raise the temperature to 140-180℃ for film blowing, and add them into the bag making machine after cooling to make degradable express bag materials.

[0064] Embodiment 5

[0065] A degradable express bag material comprises the following components calculated by weight: 40 parts of thermoplastic starch, 8 parts of plant fiber, 12 parts of modified starch, 20 parts of mixed biodegradable materials, 19 parts of paraformaldehyde (PFA), 13 parts of N-methylpyrrolidone, 35 parts of low-density polyethylene, 20 parts of polylactic acid, 9 parts of polycaprolactone, 0.5 parts of photodegradation agent, 15 parts of filler masterbatch, 1.5 parts of lubricant, 10 parts of compatibilizer, and 9 parts of photosensitizer; the filler masterbatch comprises the following components calculated by weight: 35 parts of calcium carbonate, 25 parts of talc, 13 parts of camellia peel powder, 8 parts of titanium dioxide, 12 parts of modified silicon dioxide, 15 parts of low-density polyethylene, and 7 parts of silane coupling agent.

[0066] A method for preparing a degradable courier bag material comprises the following steps:

[0067] The first step: weighing the formula amount of calcium carbonate, talcum powder, camellia peel powder, and low-density polyethylene, mixing them in a high-speed blender, and extruding and granulating them in an extruder to prepare a filling masterbatch;

[0068] Step 2: Add silicon dioxide powder to molten zinc chloride, heat at 350-400°C for 70-90 minutes; filter while hot, rinse the filter cake with deionized water, dry and sieve out particles with a particle size of 1-5 microns to obtain modified silicon dioxide;

[0069] Step 3: Mix starch, modifier and coupling agent in a high-speed mixer at 90-110°C, add glycerol, mix well, and granulate by twin-screw extrusion to obtain modified starch;

[0070] Step 4: Weigh thermoplastic starch, plant fiber, modified starch, mixed biodegradable material, paraformaldehyde (PFA), N-methylpyrrolidone 5, low-density polyethylene, polylactic acid, polycaprolactone, photodegradation agent, filler masterbatch, lubricant, compatibilizer, photosensitizer and filler masterbatch according to the formula components, put the component materials into a mixer and mix them evenly; put the mixed materials into an extruder at a temperature of 155-170°C, extrude, cool and granulate;

[0071] Step 5: Add the particles obtained in step 4 into the film blowing machine, raise the temperature to 140-180℃ for film blowing, and add them into the bag making machine after cooling to make degradable express bag materials.

[0072] Embodiment 6

[0073] A degradable express bag material comprises the following components calculated by weight: 50 parts of thermoplastic starch, 9 parts of plant fiber, 14 parts of modified starch, 23 parts of mixed biodegradable materials, 19 parts of paraformaldehyde (PFA), 6 parts of N-methylpyrrolidone, 21 parts of low-density polyethylene, 12 parts of polylactic acid, 8 parts of polycaprolactone, 0.3 parts of photodegradation agent, 8 parts of filler masterbatch, 0.4 parts of lubricant, 10 parts of compatibilizing agent, and 9 parts of photosensitizer; the filler masterbatch comprises the following components calculated by weight: 35 parts of calcium carbonate, 12 parts of talc, 10 parts of camellia peel powder, 8 parts of titanium dioxide, 11 parts of modified silicon dioxide, 10 parts of low-density polyethylene, and 6 parts of silane coupling agent.

[0074] A method for preparing a degradable courier bag material comprises the following steps:

[0075] The first step: weighing the formula amount of calcium carbonate, talcum powder, camellia peel powder, and low-density polyethylene, mixing them in a high-speed blender, and extruding and granulating them in an extruder to prepare a filling masterbatch;

[0076] Step 2: Add silicon dioxide powder to molten zinc chloride, heat at 350-400°C for 70-90 minutes; filter while hot, rinse the filter cake with deionized water, dry and sieve out particles with a particle size of 1-5 microns to obtain modified silicon dioxide;

[0077] Step 3: Mix starch, modifier and coupling agent in a high-speed mixer at 90-110°C, add glycerol, mix well, and granulate by twin-screw extrusion to obtain modified starch;

[0078] Step 4: Weigh thermoplastic starch, plant fiber, modified starch, mixed biodegradable material, paraformaldehyde (PFA), N-methylpyrrolidone 5, low-density polyethylene, polylactic acid, polycaprolactone, photodegradation agent, filler masterbatch, lubricant, compatibilizer, photosensitizer and filler masterbatch according to the formula components, put the component materials into a mixer and mix them evenly; put the mixed materials into an extruder at a temperature of 155-170°C, extrude, cool and granulate;

[0079] Step 5: Add the particles obtained in step 4 into the film blowing machine, raise the temperature to 140-180℃ for film blowing, and add them into the bag making machine after cooling to make degradable express bag materials.

[0080] The degradable courier bag material of the present invention uses a variety of bio-based and degradable ingredients, such as thermoplastic starch, plant fiber, polylactic acid, polycaprolactone, etc. These ingredients can be decomposed quickly in the natural environment, significantly reducing the pollution of traditional plastic courier bags to the environment. At the same time, the addition of photodegradation agents and photosensitizers can accelerate the degradation process of the material under light conditions, further improving its environmental friendliness.

[0081] The material of the present invention has excellent physical properties while maintaining degradability. The composite use of thermoplastic starch, modified starch, mixed biodegradable materials and low-density polyethylene improves the strength, toughness and processing performance of the material, so that it can meet the actual use requirements of express bags. In addition, the addition of filler masterbatch further enhances the performance stability of the material.

[0082] The raw materials of the present invention are widely available and renewable, such as starch can be extracted from crops such as corn and cassava, and plant fibers come from natural resources such as bamboo, cotton, and straw. This wide range of raw material sources not only reduces production costs, but also helps promote the resource utilization of agricultural waste and promote the development of a circular economy.

[0083] The addition of lubricants, compatibilizers and other additives in the material of the present invention effectively improves the processing performance of the material, making it smoother during the production process, reducing energy consumption and production costs. At the same time, these additives also help to improve the uniformity and stability of the material and ensure the quality of the final product.

[0084] The present invention can adjust the type and amount of photodegradants and photosensitizers according to different usage environments and degradation requirements; or select appropriate types and proportions of plant fibers based on cost considerations. This flexible customization capability makes the material have broad application prospects in the field of express packaging.

[0085] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A degradable courier bag material, characterized in that: The invention comprises the following components calculated by weight: 20-55 parts of thermoplastic starch, 2-10 parts of plant fiber, 5-15 parts of modified starch, 10-25 parts of mixed biodegradable materials, 15-20 parts of polyformaldehyde (PFA), 5-15 parts of N-methylpyrrolidone, 20-45 parts of low-density polyethylene, 10-30 parts of polylactic acid, 2-10 parts of polycaprolactone, 0.2-0.6 parts of photodegradation agent, 6-20 parts of filler masterbatch, 0.2-1.8 parts of lubricant, 4-12 parts of compatibilizing agent and 2-10 parts of photosensitizer; the filler masterbatch comprises the following components calculated by weight: 15-40 parts of calcium carbonate, 10-30 parts of talc, 5-15 parts of camellia peel powder, 5-10 parts of titanium dioxide, 10-15 parts of modified silicon dioxide, 8-18 parts of low-density polyethylene and 2-8 parts of silane coupling agent.

2. The degradable courier bag material according to claim 1, characterized in that: The particle size of the titanium dioxide is 5-10 microns; the particle size of the modified silicon dioxide is 1-5 microns.

3. The degradable courier bag material according to claim 2, characterized in that: The modified silicon dioxide is prepared by the following steps: adding silicon dioxide powder to molten zinc chloride, heating at 350-400° C. for 70-90 minutes; filtering while hot, rinsing the filter cake with deionized water, drying, and sieving out particles with a particle size in the range of 1-5 microns to obtain modified silicon dioxide.

4. The degradable courier bag material according to claim 1, characterized in that: The photodegradation agent is iron stearate; the lubricant is stearic acid; and the compatibilizer is low-density polyethylene grafted with maleic anhydride.

5. The degradable courier bag material according to claim 1, characterized in that: The photosensitizer is one or more of benzophenone, p-benzoquinone, and benzanthraquinone alcohol.

6. The degradable courier bag material according to claim 1, characterized in that: The preparation method of the modified starch is as follows: starch, a modifier and a coupling agent are mixed evenly in a high-speed mixer at 90-110° C., propylene glycol is added, mixed evenly, and then granulated by twin-screw extrusion to obtain the modified starch.

7. The degradable courier bag material according to claim 6, characterized in that: The starch includes but is not limited to corn starch and cassava starch; the modifier is tartaric acid; and the coupling agent is a titanate coupling agent.

8. The degradable courier bag material according to claim 1, characterized in that: The plant fiber includes one or more of bamboo fiber, cotton fiber, straw, coconut fiber and corn stalk.

9. The degradable courier bag material according to claim 1, characterized in that: The mixed biodegradable material includes one or more of PBAT, PPC and PLA.

10. A method for preparing a degradable courier bag material, characterized in that: The following steps are included: The first step: weighing the formula amount of calcium carbonate, talcum powder, camellia peel powder, and mixed biodegradable materials, mixing them in a high-speed blender, and extruding and granulating them in an extruder to prepare a filling masterbatch; Step 2: Add silicon dioxide powder to molten zinc chloride, heat at 350-400°C for 70-90 minutes; filter while hot, rinse the filter cake with deionized water, dry and sieve out particles with a particle size of 1-5 microns to obtain modified silicon dioxide; Step 3: Mix starch, modifier and coupling agent in a high-speed mixer at 90-110°C, add glycerol, mix well, and granulate by twin-screw extrusion to obtain modified starch; Step 4: Weigh thermoplastic starch, plant fiber, modified starch, mixed biodegradable material, paraformaldehyde (PFA), N-methylpyrrolidone 5, low-density polyethylene, polylactic acid, polycaprolactone, photodegradation agent, filler masterbatch, lubricant, compatibilizer, photosensitizer and filler masterbatch according to the formula components, put the component materials into a mixer and mix them evenly; put the mixed materials into an extruder at a temperature of 155-170°C, extrude, cool and granulate; Step 5: Add the particles obtained in step 4 into the film blowing machine, raise the temperature to 140-180℃ for film blowing, and add them into the bag making machine after cooling to make degradable express bag materials.