Banana fruit bag and method of making same

Abstract

The application discloses a banana fruit bag and a preparation method thereof, and relates to the packaging technical field.The banana fruit bag comprises an inner bag, an outer bag and a binding belt, and the outer bag comprises the following raw materials: 68-75 parts of a metallocene linear low-density polyethylene, 15-20 parts of a first low-density polyethylene, 5-8 parts of toughened mother particles containing ethylene-propylene-diene rubber, 0.5-1 part of an ultraviolet light absorber, 0.2-0.5 part of an antioxidant, 1-2 parts of an opening agent, 0.5-1 part of a slip agent, 3-5 parts of a moth-repellent hydrophobic auxiliary agent and 8-12 parts of color mother particles; and the inner bag comprises the following raw materials: 85-100 parts of a second low-density polyethylene, 3-6 parts of a foaming agent, 2-4 parts of a nucleating agent, 1-2.5 parts of an anti-shrinkage agent, 5-8 parts of polyethylene wax and 4-8 parts of corn cob fiber.The application develops a banana fruit bag which is safe, moth-repellent, high-breathable and high-moisture-permeable, and can buffer and prevent friction.

Description

Technical Field

[0001] This invention relates to the field of packaging technology, and in particular to a banana fruit bag and its preparation method. Background Technology

[0002] Bagging is a widely used physical protection technique in fruit tree cultivation. By covering the fruit with specially made bags, the fruit is isolated from the external environment, protecting it from pests, diseases, and birds. It also reduces pesticide residues, improves the appearance of the fruit, increases the fruit set rate, and extends the storage period of the fruit, thereby increasing the economic income of fruit farmers.

[0003] Bananas are an important economic crop in southern China, and bagging during the fruit bunch growth period is now widespread. Bagging bananas can prevent pests and diseases, significantly improve the appearance of the fruit, reduce friction damage, and increase the proportion of high-quality fruit. At the same time, bagging bananas out of season can also provide protection against cold and heat.

[0004] There are two types of banana bags currently available: paper bags and plastic film bags. Paper bags have a rough surface, which causes friction between the paper bags and the bananas, resulting in frictional damage. In addition, paper bags are expensive. Plastic film bags have poor air and moisture permeability and do not have insect-proof function, which makes it easy for microorganisms to enter the bag and multiply rapidly under high temperature and humidity conditions, leading to banana rot.

[0005] Therefore, there is a need to develop a safe, insect-proof, highly breathable and moisture-permeable, cushioning and friction-resistant banana fruit bag. Summary of the Invention

[0006] To address the aforementioned problems, this application provides a banana fruit bagging method and a method for preparing the same.

[0007] The technical solution provided in this application for a banana fruit bagging method and its preparation method is as follows:

[0008] In a first aspect, a banana fruit bag includes an inner bag, an outer bag, and a tie. The inner bag is disposed inside the outer bag. Both the inner bag and the outer bag have openings facing the same direction. The inner bag and the outer bag have a first through hole and a second through hole at the end near the opening, respectively. The tie passes through the first through hole and the second through hole. Both the inner bag and the outer bag have ventilation holes.

[0009] The outer bag comprises the following raw materials in parts by weight: 68-75 parts of metallocene linear low-density polyethylene, 15-20 parts of primary low-density polyethylene, 5-8 parts of toughening masterbatch containing EPDM rubber, 0.5-1 part of ultraviolet absorber, 0.2-0.5 parts of antioxidant, 1-2 parts of opening agent, 0.5-1 part of slip agent, 3-5 parts of insect repellent and hydrophobic additive, and 8-12 parts of color masterbatch;

[0010] The inner bag comprises the following raw materials in parts by weight: 85-100 parts of second low-density polyethylene, 3-6 parts of foaming agent, 2-4 parts of nucleating agent, 1-2.5 parts of anti-shrinkage agent, 5-8 parts of polyethylene wax, and 4-8 parts of corn husk fiber.

[0011] By adopting the above technical solution, modified polyethylene film is selected as the outer bag, and ultraviolet protectants and insect-repellent and hydrophobic additives are added. This gives the outer layer hydrophobic, insect-repellent, UV-resistant, and anti-aging protective functions. The addition of toughening masterbatch containing EPDM rubber improves the toughness of the outer bag, thereby enhancing its resistance to external impacts. It protects the bananas from sunburn by reflecting ultraviolet rays, while allowing infrared rays to pass through to ensure the bananas' basic photosynthesis. The inner layer uses pearl cotton with cushioning and heat insulation functions, which has good air and moisture permeability and prevents friction damage to the banana peel. Corn husk fibers with a hollow structure and water-guiding grooves are added to prevent condensation and water accumulation inside the bag. It promotes normal respiration of the bananas through air and oxygen permeability and has good heat preservation effect in cold environments.

[0012] By using a polyethylene outer bag and a pearl cotton inner bag to form the bagging system, and with the use of straps, the bagging system is easier to fix and prevents the bag from falling off the tree in wind and rain. Thus, the bagging system can fully play its role in resisting ultraviolet light to delay aging, preventing bird and insect damage, and preventing damage from chemical fertilizers and pesticides. It also controls light transmittance and internal temperature, allowing the bananas to maintain a suitable environment for their growth period, resulting in better quality, higher yield, and more beautiful appearance.

[0013] Optionally, the insect-repellent and hydrophobic additive is prepared by the following method:

[0014] Nano-montmorillonite was dispersed in deionized water at a solid-liquid ratio of 1:10-15 and sonicated for 20-30 minutes to form a suspension. The suspension was then heated to 70-80℃.

[0015] Add 15%-30% of the mass of nano-montmorillonite to octadecyltrimethylammonium chloride, stir and react for 2-3 hours, cool to room temperature and filter, wash the product with deionized water until the filtrate is free of Cl-, vacuum dry at 80-100℃ for 12 hours, grind and sieve to obtain intercalated modified montmorillonite.

[0016] Intercalated modified montmorillonite was dispersed in anhydrous ethanol and sonicated to form a suspension. Citronella essential oil was added at 5%-10% of the mass of intercalated modified montmorillonite. The mixture was stirred and reacted at 50-60℃ for 4-6 hours. Ethanol was removed by vacuum distillation, and the mixture was dried under vacuum and then ground to obtain an insect-repellent and hydrophobic adjuvant.

[0017] By employing the above technical solution, nano-montmorillonite forms a rough structure on the surface of the polyethylene film. This enhances hydrophobicity and, through physical piercing, disrupts the waxy layer of the insect's epidermis, achieving a repellent effect. Meanwhile, citronella oil repels pests through its volatile odor, reducing their dwell time and egg-laying on the bag surface. Intercalation modification of the nano-montmorillonite with octadecyltrimethylammonium chloride enhances the dispersibility of the nanofiller in the polyethylene system. The exposure of long alkyl chains further strengthens the hydrophobicity and improves the tensile strength of the outer bag film. Intercalation compounding of citronella oil and montmorillonite utilizes the layered structure of montmorillonite to load insect-repellent active ingredients, achieving a synergistic effect of slow-release insect repellency and enhanced hydrophobicity.

[0018] Optionally, the corn husk fiber is prepared by the following method:

[0019] Soak corn husks in a 10%-15% sodium hypochlorite solution for 10-20 minutes, then remove and wash them. Next, add sodium hydroxide and sodium silicate to the water in sequence, heat to 85-90℃, add the washed corn husks, and boil at a constant temperature for 2.5-3 hours. After boiling, remove and wash with water, then place in a 90℃ oven and dry at a constant temperature for 3-4 hours to obtain corn husk fiber.

[0020] By adopting the above technical solution, corn husk fiber is prepared by alkaline boiling to remove impurities and expose hydroxyl groups. The resulting corn husk fiber has capillary cavities inside and water-guiding grooves on the surface, thus having good air permeability, drainage and heat preservation properties.

[0021] Optionally, the corn husk fiber is selected from modified corn husk fiber and prepared through the following steps:

[0022] Place corn husk fiber in a high-speed mixer and heat it to 100-120℃. Add EVA particles at 15%-25% of the fiber mass and stir at high speed for 40-60 minutes to make the EVA layer uniformly coat the fiber surface. After cooling, sieve to obtain modified corn husk fiber.

[0023] By adopting the above technical solution, corn husk fibers, due to their high hydroxyl content, exhibit strong polarity and are prone to agglomeration and poor dispersibility in polyethylene systems. Coating the fibers with EVA eliminates the interfacial tension between the fibers and low-density polyethylene, improving the system's compatibility. Simultaneously, the coating layer does not clog the fiber's water-conducting channels and pores.

[0024] Optionally, the melt index of the metallocene linear low-density polyethylene is 1-2 g / 10 min, the melt index of the first low-density polyethylene is 0.7-1.5 g / 10 min, and the melt index test conditions are 190℃ and 2.16 kg.

[0025] By adopting the above technical solution and using polyethylene materials with a lower melt index for blending, the outer bag has better tensile strength, tear resistance, and puncture resistance, and can withstand external impacts such as wind and rain in the field and insect bites, thus avoiding premature damage to the bag.

[0026] Optionally, the melt index of the second low-density polyethylene is 1.3-2 g / 10 min, and the melt index test conditions are 190°C and 2.16 kg.

[0027] By adopting the above technical solution and selecting polyethylene materials within this range, the prepared pearl cotton has better flexibility and cushioning properties, and the foam cells are more uniform and dense.

[0028] Optionally, the opening agent is selected from one or more of oleamide and octadec-9-enylhexadecanoic acid amide, and the slip agent is selected from one or more of polyethylene wax, ethylene bis-stearamide, and pentaerythritol stearate.

[0029] Optionally, the foaming agent is selected from one or more of carbon dioxide, butane, and azodicarbonamide, and the anti-shrinkage agent is selected from one or more of polyoxyethylene alkylolamide and monoglyceride.

[0030] Optionally, the nucleating agent is a composite nucleating agent of calcium carbonate, diatomaceous earth and mixed crystal titanium dioxide, with a weight ratio of (0.5-1):(2-3):(7-9).

[0031] By adopting the above technical solution, the use of composite nucleating agents can effectively improve the uniformity of bubble distribution inside pearl cotton, while also improving the oxygen permeability of pearl cotton and ensuring the respiration of bananas.

[0032] Secondly, a method for preparing banana fruit bagging includes the following steps:

[0033] Inner bag preparation: After mixing the second low-density polyethylene, polyethylene wax, nucleating agent, anti-shrinkage agent and corn husk fiber evenly, add it to the foaming machine and heat it until the low-density polyethylene is completely melted. Then add the foaming agent, and perform traction shaping, cooling and stretching, and winding treatment to obtain pearl cotton sheet. Use a cutting machine to cut the pearl cotton sheet into blanks, heat seal the two sides and bottom of the blanks, leaving the top opening to obtain the inner bag;

[0034] Outer bag preparation: Metallocene linear low-density polyethylene, first low-density polyethylene, toughening masterbatch containing EPDM rubber, ultraviolet light absorber, antioxidant, opening agent, slip agent, insect repellent and hydrophobic additive and color masterbatch are mixed evenly and poured into a blown film machine to make a film bag, thus obtaining an outer bag with an open top.

[0035] Fruit bagging preparation: Use a punching machine to punch holes at the ends of the inner and outer bags near the opening, and at the same time, make ventilation holes in the middle of the inner and outer bags. Put the inner bag into the outer bag and use straps to connect and fix the inner and outer bags to obtain banana fruit bags.

[0036] In summary, this application has the following beneficial effects:

[0037] 1. Modified polyethylene film is used as the outer bag, with added UV protectants and insect-repellent and hydrophobic additives. This gives the outer layer hydrophobic, insect-repellent, UV-resistant, and anti-aging protective functions. It protects the bananas from sunburn by reflecting ultraviolet rays, while allowing infrared rays to pass through to ensure the bananas' basic photosynthesis. The inner layer uses pearl cotton with cushioning and heat insulation functions, offering good breathability and moisture permeability while preventing friction damage to the banana peel. Corn husk fibers with a hollow structure and water-guiding grooves are added to prevent condensation and water accumulation inside the bag. Breathability and oxygen permeability promote normal respiration in the bananas, and the bag also provides good insulation in cold environments.

[0038] By using a polyethylene outer bag and a pearl cotton inner bag to form the bagging system, and with the use of straps, the bagging system is easier to fix and prevents the bag from falling off the tree in wind and rain. Thus, the bagging system can fully play its role in resisting ultraviolet light to delay aging, preventing bird and insect damage, and preventing damage from chemical fertilizers and pesticides. It also controls light transmittance and internal temperature, allowing the bananas to maintain a suitable environment for their growth period, resulting in better quality, higher yield, and more beautiful appearance.

[0039] 2. Nano-montmorillonite forms a rough structure on the surface of the polyethylene film, enhancing hydrophobicity and repelling pests by physically piercing their cuticles and damaging their waxy layer. Citronella oil, through its volatile odor, repels pests, reducing their dwell time and egg-laying on the bag surface. Intercalation modification of nano-montmorillonite with octadecyltrimethylammonium chloride enhances the dispersibility of the nanofiller in the polyethylene system, and the exposure of long alkyl chains further strengthens hydrophobicity while improving the tensile strength of the outer bag film. Intercalation composites of citronella oil and montmorillonite utilize the layered structure of montmorillonite to load insect-repellent active ingredients, achieving a synergistic effect of slow-release insect repellency and enhanced hydrophobicity. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of the outer bag according to an embodiment of this application;

[0041] Figure 2 This is a schematic diagram of the structure of the bag according to an embodiment of this application;

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. Inner bag; 2. Outer bag; 3. Tie; 4. First through hole; 5. Second through hole; 6. Vent hole. Detailed Implementation

[0044] The present application will be further described in detail below with reference to Examples 1-5 and Comparative Examples 1-2.

[0045] The main sources of raw materials in the following examples and comparative examples are:

[0046] The melt index of metallocene linear low-density polyethylene is 1-2 g / 10 min. The specific brand selected is Primavista Japan, model EVOLUE™ SP1520, with a melt index of 1.5 g / 10 min and a density of 0.912 g / cm³. 3 The test conditions were 190℃ and 2.16kg.

[0047] The first low-density polyethylene has a melt index of 0.7-1.5 g / 10 min, specifically ExxonMobil's LD 100.LQ, with a melt index of 1.0 g / 10 min and a density of 0.919 g / cm³. 3 The test conditions were 190℃ and 2.16kg.

[0048] The second low-density polyethylene has a melt index of 1.3-2 g / 10 min, specifically the LyondellBasell Lupolen® 1845H, with a melt index of 1.5 g / 10 min and a density of 0.923 g / cm³. 3 The test conditions were 190℃ and 2.16kg.

[0049] The toughening masterbatch containing EPDM rubber was purchased from Guangdong Dicai New Materials Co., Ltd., model number 82270.

[0050] Preparation Example

[0051] Preparation Example 1-1

[0052] Preparation of corn husk fiber

[0053] Soak 400g of corn husks in 500g of 10% sodium hypochlorite solution for 10 minutes, then remove and wash. Add 16g of sodium hydroxide and 30g of sodium silicate to 1600ml of water, heat to 85℃, add the washed corn husks, and boil at a constant temperature for 2.5 hours. Remove, wash with water, and dry in a 90℃ oven for 3 hours to obtain corn husk fiber.

[0054] Preparation Examples 1-2

[0055] Preparation of corn husk fiber

[0056] Soak 400g of corn husks in 500g of 15% sodium hypochlorite solution for 20 minutes, then remove and wash. Next, add 20g of sodium hydroxide and 35g of sodium silicate to 1600ml of water, heat to 90℃, add the washed corn husks, and boil at a constant temperature for 3 hours. Remove and wash with water, then dry in a 90℃ oven for 4 hours to obtain corn husk fiber.

[0057] Preparation Example 2-1

[0058] Preparation of insect-repellent and hydrophobic additives

[0059] 100g of nano-montmorillonite was dispersed in 1000g of deionized water at a solid-liquid ratio of 1:10, and sonicated for 20 minutes to prepare a suspension. The suspension was then heated to 70℃.

[0060] Add 15g of octadecyltrimethylammonium chloride to the suspension, stir and react for 2 hours, cool to room temperature, filter, and wash the product with deionized water until the filtrate is free of Cl. - The mixture was vacuum dried at 80℃ for 12 hours, then ground and sieved to obtain intercalated modified montmorillonite.

[0061] Intercalated modified montmorillonite was dispersed in anhydrous ethanol and sonicated to form a suspension. Citronella oil was added at 5% of the mass of intercalated modified montmorillonite. The mixture was stirred and reacted at 50°C for 4 hours. Ethanol was removed by vacuum distillation, and the mixture was dried under vacuum and then ground to obtain an insect-repellent and hydrophobic adjuvant.

[0062] Preparation Example 2-2

[0063] Preparation of insect-repellent and hydrophobic additives

[0064] 100g of nano-montmorillonite was dispersed in 1500g of deionized water at a solid-liquid ratio of 1:15, and sonicated for 30 minutes to prepare a suspension. The suspension was then heated to 80℃.

[0065] Add 30g of octadecyltrimethylammonium chloride to the suspension, stir for 3 hours, cool to room temperature, filter, and wash the product with deionized water until no Cl- is found in the filtrate. - The mixture was vacuum dried at 100℃ for 12 hours, then ground and sieved to obtain intercalated modified montmorillonite.

[0066] Intercalated modified montmorillonite was dispersed in anhydrous ethanol and sonicated to form a suspension. Citronella oil was added at 10% of the mass of the intercalated modified montmorillonite. The mixture was stirred and reacted at 60°C for 6 hours. The ethanol was removed by vacuum distillation, and the mixture was dried under vacuum and then ground to obtain an insect-repellent and hydrophobic adjuvant.

[0067] Preparation Example 3-1

[0068] Preparation of modified corn husk fiber

[0069] 100g of corn husk fiber prepared in Example 1-1 was placed in a high-speed mixer, heated to 100℃, and 15g of EVA particles were added. The mixture was stirred at high speed for 40 minutes to make the EVA layer uniformly coat the fiber surface. After cooling, the mixture was sieved to obtain modified corn husk fiber.

[0070] Preparation Example 3-2

[0071] Preparation of modified corn husk fiber

[0072] 100g of corn husk fiber prepared in Preparation Examples 1-2 was placed in a high-speed mixer, heated to 120°C, and 25g of EVA particles were added. The mixture was stirred at high speed for 60 minutes to ensure that the EVA layer uniformly coated the fiber surface. After cooling, the mixture was sieved to obtain modified corn husk fiber. Example

[0073] Example 1

[0074] This application provides a banana fruit bagging method, as shown in the attached illustration. Figure 1 and attached Figure 2 The bag includes an inner bag 1, an outer bag 2, and a strap 3. The inner bag 1 is located inside the outer bag 2. Both the inner bag 1 and the outer bag 2 have openings facing the same direction. The inner bag 1 and the outer bag 2 have a first through hole 4 and a second through hole 5 at the end near the opening, respectively. The strap 3 passes through the first through hole 4 and the second through hole 5. The middle part of both the inner bag 1 and the outer bag 2 has ventilation holes 6 that are staggered to each other to enhance the breathability of the bag and prevent the bananas from falling out.

[0075] The outer bag contains the following materials:

[0076] Metallocene linear low-density polyethylene 68kg;

[0077] First, 15 kg of low-density polyethylene;

[0078] 5 kg of toughening masterbatch containing EPDM rubber was purchased from Guangdong Dicai New Material Co., Ltd., model number 82270.

[0079] 0.5 kg of ultraviolet light absorber, UV-531, purchased from Wuhan Xindongyi Chemical Co., Ltd.

[0080] Antioxidant 0.2kg, using antioxidant 1010, brand name BASF Irganox;

[0081] 1 kg of opening agent, oleic acid amide is selected;

[0082] 0.5 kg of slip agent, made of polyethylene wax;

[0083] 3 kg of the insect-repellent and hydrophobic adjuvant prepared in Example 2-1;

[0084] Masterbatch 8kg;

[0085] The inner bag includes the following materials:

[0086] 85 kg of the second low-density polyethylene;

[0087] 3 kg of foaming agent, using carbon dioxide foaming agent;

[0088] 2 kg of nucleating agent, a composite nucleating agent consisting of calcium carbonate, diatomaceous earth and mixed crystal titanium dioxide in a ratio of 0.5:2:7;

[0089] 1 kg of anti-shrinkage agent, selected from polyoxyethylene alkylolamide;

[0090] 5 kg of polyethylene wax;

[0091] 4 kg of corn husk fiber was obtained from Preparation Example 1-1.

[0092] The method for preparing banana fruit bagging includes the following steps:

[0093] Inner bag preparation: After mixing the second low-density polyethylene, polyethylene wax, nucleating agent, anti-shrinkage agent and corn husk fiber evenly, add it to the foaming machine and heat it until the low-density polyethylene is completely melted. Then add the foaming agent, and perform traction shaping, cooling and stretching, and winding treatment to obtain pearl cotton sheet. Use a cutting machine to cut the pearl cotton sheet into blanks, heat seal the two sides and bottom of the blanks, leaving the top opening to obtain the inner bag;

[0094] Outer bag preparation: Metallocene linear low-density polyethylene, first low-density polyethylene, toughening masterbatch containing EPDM rubber, ultraviolet light absorber, antioxidant, opening agent, slip agent, insect repellent and hydrophobic additive and color masterbatch are mixed evenly and poured into a blown film machine to make a film bag, thus obtaining an outer bag with an open top.

[0095] Fruit bagging preparation: Use a punching machine to punch holes at the end of the inner bag and outer bag near the opening. Place the inner bag inside the outer bag and use straps to connect and fix the inner bag and outer bag to obtain banana fruit bags.

[0096] Examples 2-5

[0097] The main difference between Examples 2-5 and Example 1 lies in the different raw material components and materials used for the inner and outer bags. The specific differences are shown in Table 1.

[0098] Table 1

[0099] Outer bag raw materials Example 2 Example 3 Example 4 Example 5 Metallocene linear low-density polyethylene 75kg 72kg 68kg 75kg First low-density polyethylene 20kg 18kg 15kg 20kg Toughening masterbatch containing EPDM rubber 8kg 6kg 5kg 8kg UV absorber 1kg, UV-326 0.7kg, UV-327 0.5kg, UV-531 1kg, UV-326 antioxidants 0.5kg, antioxidant 1076 0.3kg, antioxidant 168 0.2kg, Antioxidant 1010 0.5kg, antioxidant 1076 Opening agent 2kg, Octadec-9-enylhexadecanoic acid amide 1.5kg, oleamide 1kg, oleamide 2kg, Octadec-9-enylhexadecanoic acid amide slip 1kg, ethylene bis-stearamide 0.8 kg, pentaerythritol stearate 0.5kg, polyethylene wax 1kg, ethylene bis-stearamide Insect-repellent and hydrophobic additives 5kg, Preparation Example 2-2 4kg, Preparation Example 2-1 3kg, Preparation Example 2-1 5kg, Preparation Example 2-2 Masterbatch 12kg 10kg 8kg 12kg Inner bag raw materials Example 2 Example 3 Example 4 Example 5 Second low-density polyethylene 85kg 93kg 85kg 85kg foaming agent 6kg, butane 4kg, azodicarbonamide 3kg, carbon dioxide 6kg, butane nucleating agent 4kg 3kg 2kg 4kg anti-shrinkage agent 2.5kg, monoglycerides 2.1kg, monoglycerides 1kg, polyoxyethylene alkylolamide 2.5kg, monoglycerides Polyethylene wax 8kg 6kg 5kg 8kg Corn husk fiber 8kg, Preparation Examples 1-2 5.5 kg, Preparation Example 1-1 4kg, Preparation Example 3-1 8kg, Preparation Example 3-2

[0100] For the nucleating agents listed in Table 1, in Examples 2 and 5, a composite nucleating agent of calcium carbonate, diatomaceous earth, and mixed-crystal titanium dioxide in a ratio of 1:3:9 was selected; in Example 3, a composite nucleating agent of calcium carbonate, diatomaceous earth, and mixed-crystal titanium dioxide in a ratio of 0.8:2.5:8 was selected; and in Example 4, a composite nucleating agent of calcium carbonate, diatomaceous earth, and mixed-crystal titanium dioxide in a ratio of 0.5:2:7 was selected. Comparative Example

[0101] Comparative Example 1

[0102] The difference between this comparative example and Example 1 is that the corn husk fibers in the inner bag material are different.

[0103] In this comparative example, no corn husk fiber was added to the inner bag material.

[0104] Comparative Example 2

[0105] The difference between this comparative example and Example 1 is that the insect-repellent and hydrophobic additives in the outer bag material are different.

[0106] In this comparative example, no insect-repellent and water-repellent additives were added to the outer bag material.

[0107] Blank example

[0108] The blank example selects bananas that have not been bagged.

[0109] The following performance tests were conducted on the banana fruit bags prepared in Examples 1-5, Comparative Examples 1-2, and the blank example.

[0110] Test Method: Bananas were planted in March and bagged on November 30th. In the banana plantation, 24 healthy banana trees with similar growth and the same bud-dropping time were selected. Bagging was performed 15 days after bud drop. When bagging, the bag opening was opened, and the entire bunch of bananas was placed into the inner bag from bottom to top. The bag was then secured to the banana fruit by pulling the ends of the binding straps. The 24 banana trees were bagged using Examples 1-5 and Comparative Examples 1-2, respectively, while 3 trees were not bagged as a control group.

[0111] After 43 days of bagging, the bananas are about 80% ripe and are harvested at this point. After harvesting, they are treated with 500 mg / L ethephon spray to accelerate ripening, dried, and then placed in perforated plastic bags and stored in a cold storage at 20°C.

[0112] Banana appearance quality testing:

[0113] Single fruit weight determination: An electronic balance with an accuracy of 0.01g was used to determine the average weight of the fruit and record it.

[0114] Edible pulp determination: After the bananas are ripened, the fruit stems are removed and the fruit is weighed. Then the pulp and peel are carefully separated and the peel weight is measured.

[0115] The edible rate of fruit (%) = (W0-W1) / W0×100%, where W0 and W1 are the weights of the fruit and peel, respectively, in g.

[0116] Banana internal quality testing:

[0117] Dry matter mass fraction: The fresh weight of bananas was measured on the day of harvest, and the dry weight was measured after drying at 80℃ to constant weight. The dry matter mass fraction was then calculated.

[0118] Soluble solids content: Take 20g of banana pulp from the middle section, add an equal amount of distilled water to homogenize, filter with double-layer gauze, take a small amount of filtrate, and determine the soluble solids content using a PR-32α saccharimeter.

[0119] The performance test results are shown in Table 2.

[0120] Table 2

[0121] Sample Single fruit weight (g) Edible rate (%) Dry matter mass fraction (%) Soluble solids content (%) Example 1 175.23 68.65 18.5 21.50 Example 2 175.79 68.74 18.2 21.52 Example 3 174.56 68.43 18.3 21.48 Example 4 183.47 69.81 19.0 22.73 Example 5 183.28 69.76 19.2 22.69 Comparative Example 1 171.91 67.89 17.2 19.47 Comparative Example 2 171.34 68.23 16.9 19.62 Blank example 168.65 70.27 15.7 18.56

[0122] According to the data in Table 2, the banana fruit bagging method used in this application, namely the double-layer bagging of a modified polyethylene film outer bag and a pearl cotton inner bag, has a beneficial effect on the growth of banana fruits. Specifically:

[0123] By using bagging, especially inner bags with heat-insulating properties, the banana's growing temperature becomes more stable. Simultaneously, the addition of corn husk fibers with natural water-guiding channels traps air, forming continuous breathable channels within the foamed matrix, resulting in excellent air permeability and drainage, preventing high humidity and waterlogging. The outer bag contains hydrophobic and insect-repellent agents to prevent high humidity inside the bag from inhibiting fruit enlargement. The addition of nano-montmorillonite enhances the outer bag's tensile and tear resistance, ensuring it is not easily damaged and always provides a stable microenvironment for fruit growth. Citronella essential oil repels aphids, thrips, and other piercing-sucking pests, reducing nutrient theft from the fruit and preventing pest damage.

[0124] Bagging protects the fruit from the stimulation and damage caused by factors such as wind, rain, pesticides, and mechanical friction, allowing the peel to develop normally and well. By providing a stable growth microenvironment, it improves the appearance quality of the fruit, resulting in uniform peel coloring and fewer diseases, pests, and mechanical damage.

[0125] Regarding the banana fruit bagging of Example 1, the following performance tests were also conducted, and the test results are shown in Table 3.

[0126] Table 3

[0127] performance Require Actual measurement Light transmittance (%) Infrared ≥30 33 Light transmittance (%) UV ≤6 4.5 Transverse tensile strength (MPa) ≥25 31.997 Longitudinal tensile strength (MPa) ≥25 32.91 Lateral elongation (%) ≥400% 740.866% Longitudinal elongation (%) ≥400% 684.09% Puncture force (N) ≥2 2.577

[0128] The banana fruit bag prepared in this application can achieve excellent anti-ultraviolet performance, blocking ultraviolet light to protect bananas from sunburn. More than 30% of infrared rays can penetrate the banana fruit bag, ensuring the banana's basic photosynthesis. In addition, the heat preservation effect allows the banana to have a longer growth period, resulting in higher nutrient content, richer nutrition, and better taste.

[0129] Judging from performance indicators such as tensile strength, tensile elongation, and puncture force, the banana fruit bag of this application can ensure good mechanical properties, resist external impacts such as wind, rain, and insect bites in the field, prevent premature damage to the bag, and enhance the protective effect of the bag on the fruit inside.

[0130] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A banana fruit bagging method, characterized in that: It includes an inner bag (1), an outer bag (2) and a strap (3). The inner bag (1) is located inside the outer bag (2). Both the inner bag (1) and the outer bag (2) have openings facing the same direction. The inner bag (1) and the outer bag (2) have a first through hole (4) and a second through hole (5) respectively at the end near the opening. The strap (3) passes through the first through hole (4) and the second through hole (5). Both the inner bag (1) and the outer bag (2) have ventilation holes (6). The outer bag comprises the following raw materials in parts by weight: 68-75 parts of metallocene linear low-density polyethylene, 15-20 parts of primary low-density polyethylene, 5-8 parts of toughening masterbatch containing EPDM rubber, 0.5-1 part of ultraviolet absorber, 0.2-0.5 parts of antioxidant, 1-2 parts of opening agent, 0.5-1 part of slip agent, 3-5 parts of insect repellent and hydrophobic additive, and 8-12 parts of color masterbatch; The inner bag comprises the following raw materials in parts by weight: 85-100 parts of second low-density polyethylene, 3-6 parts of foaming agent, 2-4 parts of nucleating agent, 1-2.5 parts of anti-shrinkage agent, 5-8 parts of polyethylene wax, and 4-8 parts of corn husk fiber; The insect-repellent and hydrophobic additive is prepared by the following method: Nano-montmorillonite was dispersed in deionized water at a solid-liquid ratio of 1:10-15 and sonicated for 20-30 minutes to form a suspension. The suspension was then heated to 70-80℃. Add 15%-30% (by weight) of nano-montmorillonite to octadecyltrimethylammonium chloride, stir for 2-3 hours, cool to room temperature, filter, and wash the product with deionized water until the filtrate is free of Cl. - Vacuum dried at 80-100℃ for 12 hours, then ground and sieved to obtain intercalated modified montmorillonite; Intercalated modified montmorillonite was dispersed in anhydrous ethanol and sonicated to form a suspension. Citronella essential oil was added at 5%-10% of the mass of intercalated modified montmorillonite. The mixture was stirred and reacted at 50-60℃ for 4-6 hours. Ethanol was removed by vacuum distillation, and the mixture was dried under vacuum and then ground to obtain an insect-repellent and hydrophobic adjuvant. The corn husk fiber is selected from modified corn husk fiber and is prepared through the following steps: Soak corn husks in a 10%-15% sodium hypochlorite solution for 10-20 minutes, then remove and wash them. Add sodium hydroxide and sodium silicate to water in sequence, heat to 85-90℃, add the washed corn husks, and boil at a constant temperature for 2.5-3 hours. Remove and wash with water, then dry in a 90℃ oven for 3-4 hours to obtain corn husk fiber. Place corn husk fiber in a high-speed mixer and heat it to 100-120℃. Add EVA particles at 15%-25% of the fiber mass and stir at high speed for 40-60 minutes to make the EVA layer uniformly coat the fiber surface. After cooling, sieve to obtain modified corn husk fiber.

2. The banana fruit bagging method according to claim 1, characterized in that: The melt index of the metallocene linear low-density polyethylene is 1-2 g / 10 min, and the melt index of the first low-density polyethylene is 0.7-1.5 g / 10 min. The melt index test conditions are 190℃ and 2.16 kg.

3. The banana fruit bagging method according to claim 1, characterized in that: The melt index of the second low-density polyethylene is 1.3-2 g / 10 min, and the test conditions for the melt index are 190℃ and 2.16 kg.

4. The banana fruit bagging method according to claim 1, characterized in that: The opening agent is selected from one or more of oleamide and octadec-9-enylhexadecanoic acid amide, and the slip agent is selected from one or more of polyethylene wax, ethylene bis-stearamide, and pentaerythritol stearate.

5. A banana fruit bagging method according to claim 1, characterized in that: The foaming agent is selected from one or more of carbon dioxide, butane, and azodicarbonamide, and the anti-shrinkage agent is selected from one or more of polyoxyethylene alkylolamide and monoglyceride.

6. A banana fruit bagging method according to claim 1, characterized in that: The nucleating agent is a composite nucleating agent of calcium carbonate, diatomaceous earth and mixed crystal titanium dioxide, with a weight ratio of (0.5-1):(2-3):(7-9).

7. A method for preparing a banana fruit bag according to any one of claims 1-6, characterized in that, Includes the following steps: Inner bag preparation: After uniformly mixing the second low-density polyethylene, polyethylene wax, nucleating agent, anti-shrinkage agent and corn husk fiber, add it to the foaming machine and heat it until the second low-density polyethylene is completely melted. Then add the foaming agent, and perform traction shaping, cooling and stretching, and winding treatment to obtain pearl cotton sheet. Use a cutting machine to cut the pearl cotton sheet into blanks, heat seal the two sides and bottom of the blanks, leaving the top opening to obtain the inner bag; Outer bag preparation: Metallocene linear low-density polyethylene, first low-density polyethylene, toughening masterbatch containing EPDM rubber, ultraviolet light absorber, antioxidant, opening agent, slip agent, insect repellent and hydrophobic additive and color masterbatch are mixed evenly and poured into a blown film machine to make a film bag, thus obtaining an outer bag with an open top. Fruit bagging preparation: Use a punching machine to punch holes at the ends of the inner and outer bags near the opening, and at the same time, make ventilation holes in the middle of the inner and outer bags. Put the inner bag into the outer bag and use straps to connect and fix the inner and outer bags to obtain banana fruit bags.

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