A type of express delivery packaging film with moisture-proof and oxygen-barrier functions

Abstract

This utility model belongs to the field of packaging film, and in particular to a packaging film for express delivery with moisture-proof and oxygen-barrier functions. Addressing the problems of insufficient moisture-proof and oxygen-barrier performance, lack of self-healing ability, limited preservation function, and poor environmental adaptability of existing packaging films, the following solution is proposed: a base film layer made of recycled PET and polylactic acid; a functional layer covering the base film layer for preserving the goods; and a repair layer covering the functional layer for repairing cracks. In this utility model, the base film layer uses a blend of recycled PET and polylactic acid to reduce dependence on petroleum resources. Combined with the first and second reinforcing ribs interlaced within the outer indicator layer, a three-dimensional mesh support structure is formed, improving the puncture resistance of the film material. The repair layer repairs cracks through a cascade reaction of the first repair capsule (polyethyleneimine) and the second repair capsule (epimchlorohydrin-modified starch), in conjunction with paraffin phase change microspheres (trigger medium).

Description

Technical Field

[0001] This utility model relates to the field of packaging film technology, and in particular to a packaging film for express delivery with moisture-proof and oxygen-barrier functions. Background Technology

[0002] With the rapid development of cold chain logistics and fresh food e-commerce, the moisture-proof, oxygen-barrier, and preservation properties of express packaging films directly affect product quality and shelf life. Traditional packaging films face the following technical bottlenecks: Insufficient moisture and oxygen barrier properties: Single-material packaging films are prone to micro-cracks due to transportation vibrations, leading to the penetration of moisture and oxygen, which accelerates food spoilage; Lack of self-healing ability: After damage, manual replacement of packaging is required, which increases logistics costs, and traditional additive self-healing agents (such as microcapsules) can easily reduce the light transmittance of the membrane material; Limited preservation function: It relies solely on passive barrier and cannot actively degrade ripening gases such as ethylene, resulting in a short shelf life for fresh food. Poor environmental adaptability: Temperature fluctuations during transportation are difficult to monitor, and abnormal temperature control leads to a high risk of product deterioration; To address the aforementioned issues, this application proposes a packaging film for express delivery that has moisture-proof and oxygen-barrier functions. Utility Model Content

[0003] The purpose of this invention is to address the shortcomings of existing packaging films, such as insufficient moisture-proof and oxygen-barrier properties: single-material packaging films are prone to micro-cracks due to transportation vibrations, leading to moisture and oxygen penetration and accelerating food spoilage; lack of self-repair capabilities: after damage, manual replacement of packaging is required, increasing logistics costs, and traditional additive self-repair agents (such as microcapsules) can easily reduce the light transmittance of the film material; limited preservation function: relying solely on passive barrier, unable to actively degrade ripening gases such as ethylene, resulting in a short shelf life for fresh food; and poor environmental adaptability: temperature fluctuations during transportation are difficult to monitor, and abnormal temperature control leads to a high risk of product spoilage. Therefore, this invention proposes a packaging film for express delivery with moisture-proof and oxygen-barrier functions.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A packaging film for express delivery with moisture-proof and oxygen-barrier functions includes a base film layer made of recycled PET and polylactic acid; The functional layer, which covers the base film layer, is used to preserve the contents of items. The repair layer, which covers the functional layer, is used to repair cracks; An outer indicator layer covers the repair layer and contains reinforcing components to enhance strength. When the membrane is compressed and microcracks are generated, the microcapsules in the repair layer rupture, and polyethyleneimine and epoxy starch undergo ring-opening polymerization to repair the cracks. Paraffin phase change microspheres simultaneously fill the pores to restore the continuity of the barrier. When the transport environment temperature exceeds 33°C for 2 hours, the outer indicator layer changes from blue to white to indicate abnormal temperature control.

[0005] In one possible design, the reinforcing component includes a plurality of first reinforcing ribs and a plurality of second reinforcing ribs disposed inside the outer indicator layer, the first and second reinforcing ribs being arranged alternately in a grid pattern.

[0006] In one possible design, the first and second reinforcing ribs are formed from fiber bundles with a diameter of 100-200 μm by cross-linking PVA with dialdehyde starch.

[0007] In one possible design, the functional layer comprises a zeolite imidazole ester loaded with sodium copper chlorophyllin and a photosensitizer, which is activated under visible light to decompose ethylene gas and extend the shelf life of fresh food.

[0008] In one possible design, the repair layer includes a first repair capsule and a second repair capsule. The first repair capsule is a urea-formaldehyde wall material encapsulating polyethyleneimine, and the second repair capsule is a gelatin-gum arabic wall material encapsulating epichlorohydrin-modified starch. When the microcapsules rupture, the polyethyleneimine and the epoxy starch undergo ring-opening polymerization to repair the cracks.

[0009] In one possible design, the repair layer further includes a triggering medium, which is paraffin phase change microspheres that melt when the temperature rises to trigger the repair reaction.

[0010] In one possible design, the surface of the outer indicator layer is coated with thermochromic microcapsules, which change from blue to white when the ambient temperature during transport is >33°C for 2 hours to provide an irreversible temperature control warning.

[0011] In one possible design, multiple easy-tear openings are provided on both sides of the outer indicator layer, repair layer, functional layer and base film layer to allow the packaging to be torn open by hand.

[0012] In one possible design, the bottom of the base film layer is integrally formed with a hemispherical bubble array, and the interior of the base film layer has multiple through holes located in the area between the bubbles to provide cushioning and promote air circulation.

[0013] In this application, when the membrane layer is compressed and microcracks are generated, the stress at the crack tip causes the microcapsules to rupture. PEI then undergoes ring-opening polymerization with epoxy starch, repairing the cracks. Paraffin phase change microspheres simultaneously fill the pores, restoring the barrier continuity. Compared to traditional self-healing agent solutions, the repair efficiency is increased by 2 times without affecting the initial light transmittance. When the transportation environment is above 33°C for 2 hours, the outer color layer changes from blue to white, indicating abnormal temperature control. After the goods are unsealed, the sodium copper chlorophyllin in the functional layer is activated under visible light, decomposing ethylene gas and extending the shelf life of fresh food. This solution upgrades the traditional barrier film into an active preservation system.

[0014] Beneficial effects: The base film layer is made of recycled PET and polylactic acid blend, which reduces dependence on petroleum resources. Combined with the first and second reinforcing ribs interlaced in the outer indicator layer, a three-dimensional mesh support structure is formed, which improves the puncture resistance and tear resistance of the film material, meeting the needs of rough handling scenarios in express delivery.

[0015] The repair layer completes the repair of cracks through the cascade reaction of the first repair capsule (polyethyleneimine) and the second repair capsule (epicochloropropane modified starch), in conjunction with paraffin phase change microspheres (trigger medium). The repair efficiency is twice that of the traditional microcapsule solution, and the paraffin microspheres restore the membrane material barrier continuity after filling the pores.

[0016] The functional layer is loaded with sodium copper chlorophyllin in a zeolite imidazolium ester (ZIF) structure. Under visible light irradiation, the photosensitizer is activated to target and decompose ethylene gas in the packaging, thus extending the shelf life of fresh foods (such as strawberries). At the same time, the ZIF pores adsorb oxygen concentration, thus inhibiting microbial growth through a dual mechanism.

[0017] The outer indicator layer is coated with thermochromic microcapsules. When the ambient temperature during transportation exceeds 33°C for 2 hours, the dye molecules inside the capsule undergo a conformational change, and the surface of the membrane changes from blue to white, providing an irreversible warning of abnormal temperature control and avoiding hidden losses caused by cold chain interruptions.

[0018] Easy-tear openings are pre-set on both sides of the film layer, and the hemispherical bubble cushioning design at the bottom of the base film layer improves the ease of opening the packaging. At the same time, the bubble structure reduces external impact stress and reduces the rate of damage during transportation. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of a packaging film for express delivery with moisture-proof and oxygen-barrier functions proposed in this utility model. Figure 2 This is a two-dimensional structural diagram of a packaging film for express delivery with moisture-proof and oxygen-barrier functions proposed in this utility model. Figure 3 This is an exploded view of a packaging film for express delivery with moisture-proof and oxygen-barrier functions proposed in this utility model.

[0020] In the diagram: 1. Outer indicator layer; 2. First reinforcing rib; 3. Hemispherical bubble; 4. Base film layer; 5. Functional layer; 6. Repair layer; 7. Second reinforcing rib; 8. Tear-off opening; 9. Through hole. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0022] In one embodiment; reference Figure 1-3 A packaging film, comprising: The base film layer 4 is made by mixing recycled PET particles and polylactic acid particles in a 70:30 mass ratio, melt-blending them at 180°C using a twin-screw extruder, and then preparing a 0.1 mm thick base film by casting. The bottom of the base film is formed using a hot-pressing process to create an array of hemispherical bubbles 3 with a diameter of 2 mm and a height of 1.5 mm, with a bubble spacing of 3 mm. Through-holes 9 with a diameter of 0.5 mm are set every 5 cm inside the base film, and these through-holes 9 are processed using laser drilling.

[0023] Functional layer 5 is applied to the base film surface using a microgravure coating process, with a coating thickness of 20 μm. The material of functional layer 5 is made by impregnating a sodium copper chlorophyllin solution onto a zeolite imidazole carrier, with the sodium copper chlorophyllin loading being 0.5% of the carrier's mass. After coating, it is cured by hot air drying at 80°C.

[0024] Repair layer 6 is applied to the surface of functional layer 5 using a double-sided coating machine, with a thickness of 30 μm. Repair layer 6 contains three types of components: the first type consists of urea-formaldehyde microcapsules with a particle size of 5-8 μm, encapsulating a polyethyleneimine solution inside; the second type consists of gelatin-gum arabic microcapsules with a particle size of 10-15 μm, filled with epichlorohydrin-modified starch powder; and the third type consists of paraffin phase change microspheres with a particle size of 20 μm. The three types of components are mixed at a mass ratio of 8:10:5 and dispersed in a polyvinyl alcohol matrix.

[0025] The outer indicator layer 1 is coated with a 15μm layer using an electrostatic spraying process. The material is thermochromic microcapsules containing crystal violet lactone, and the color-changing temperature is set at 33℃. Reinforcing components are embedded within this layer: the first reinforcing rib 2 is made of a dialdehyde starch cross-linked polyvinyl alcohol solution, electrospun into longitudinal fiber bundles with a diameter of 150μm, arranged in parallel with a spacing of 2mm; the second reinforcing rib 7 is made of the same material and arranged diagonally at 45°, forming a mesh structure with the first reinforcing rib 2.

[0026] This application can be used in the field of packaging films, or in other fields applicable to this application.

[0027] In another embodiment; reference Figure 1-3A type of express delivery packaging film with moisture-proof and oxygen-barrier functions is used in the packaging film field. Each layer has easy-tear edges. V-shaped notches are made every 10cm on both sides of the composite film, with a notch depth of 2 / 3 of the total thickness and a notch angle of 60°. The four-layer structure is finally laminated using a hot-pressing laminating unit at 100℃ and 0.5MPa pressure, with the total thickness controlled at 0.18mm.

[0028] When cracks less than 50 μm wide appear on the membrane surface, the crack stress causes adjacent microcapsules to rupture. Upon contact with epoxy starch, the polyethyleneimine solution undergoes a ring-opening polymerization reaction, completing crack filling and repair within 30 minutes. When the ambient temperature exceeds 33°C for 120 minutes, the outer indicator layer 1 changes from blue to white. Under visible light irradiation, the sodium copper chlorophyll in the functional layer 5 is activated to generate free radicals, decomposing ethylene gas into water and carbon dioxide. During transportation, when the membrane material is compressed, the bottom bubble array provides cushioning protection, and the through-holes 9 promote air circulation. The reinforcing mesh increases the tensile strength to 80 MPa, and the easy-tear opening 8 allows for manual tearing of the packaging.

[0029] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A packaging film for express delivery having a moisture-proof and oxygen-blocking function, characterized by comprising: include: Base film layer (4); The functional layer (5) covers the base film layer (4) and is used to preserve the items; Repair layer (6), covering the functional layer (5), is used to repair cracks; An outer indicator layer (1) covers the repair layer (6) and has a reinforcing component for enhancing strength inside.

2. The packaging film for delivery according to claim 1, characterized by The reinforcing component includes a plurality of first reinforcing ribs (2) and a plurality of second reinforcing ribs (7) disposed inside the outer indicator layer (1), wherein the first reinforcing ribs (2) and the second reinforcing ribs (7) are arranged in an alternating grid pattern.

3. The packaging film for delivery according to claim 2, characterized by The first reinforcing rib (2) and the second reinforcing rib (7) are fiber bundles with a diameter of 100-200 μm formed by cross-linking PVA with dialdehyde starch.

4. The packaging film for delivery according to claim 1, characterized by The repair layer (6) includes a first repair capsule and a second repair capsule. The first repair capsule is polyethyleneimine wrapped in urea-formaldehyde wall material, and the second repair capsule is epichlorohydrin modified starch wrapped in gelatin-gum arabic wall material.

5. The packaging film for delivery according to claim 4, characterized by The repair layer (6) also includes a triggering medium, which is paraffin phase change microspheres.

6. The packaging film for delivery according to claim 1, wherein The surface of the outer indicator layer (1) is coated with thermochromic microcapsules.

7. The packaging film for delivery according to claim 1, wherein Multiple easy-tear openings (8) are provided on both sides of the outer indicator layer (1), repair layer (6), functional layer (5) and base film layer (4).

8. The packaging film for delivery according to any one of claims 1 to 7, characterized by, The bottom of the base film layer (4) is integrally formed with an array of hemispherical bubbles (3), and the interior of the base film layer (4) is provided with multiple through holes (9), which are located in the area between the bubbles (3).

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