A degradable temperature control corrugated carton for cold chain logistics and a recycling method thereof

Abstract

The application relates to the packaging and recycling fields, in particular to a degradable temperature control corrugated paper box for cold chain logistics and a recycling method, which comprises a paper box body made of corrugated paper board and at least one biodegradable functional composite film which is separably adhered to the outer surface and / or the inner surface of the paper box body through a water-soluble adhesive layer, the biodegradable functional composite film comprises a hydrophobic surface layer, a phase change heat preservation middle layer and a hydrophilic inner layer, the phase change heat preservation middle layer is dispersed with phase change material microcapsules, an irreversible thermochromic indicating label is arranged on the paper box body or the biodegradable functional composite film, and the application further comprises a recycling method of the degradable temperature control corrugated paper box. The application achieves the technical effects of effectively controlling the temperature in the cold chain logistics, degrading the paper box, facilitating recycling and utilization, reducing environmental pollution, and directly reflecting the temperature condition through the thermochromic indicating label.

Description

Technical Field

[0001] This invention relates to the field of packaging and recycling technology, and in particular to a biodegradable temperature-controlled corrugated cardboard box for cold chain logistics and a recycling method thereof. Background Technology

[0002] With the rapid development of industries such as fresh food e-commerce and pharmaceutical cold chain, the demand for cold chain logistics packaging is increasing daily. Corrugated cardboard boxes, with their advantages of low cost, light weight, and ease of processing, have been widely used in the cold chain packaging field. They provide basic protection and containment for the transportation and storage of cold chain goods, enabling cold chain logistics to be more efficient and convenient. Their widespread use has not only reduced the cost of cold chain logistics but also improved the efficiency of goods transportation, thus occupying an important position in the cold chain logistics industry.

[0003] In existing technologies, several improvement measures are typically adopted to address the poor moisture-proof and thermal insulation performance of ordinary corrugated cardboard boxes. On one hand, moisture-proofing agents, such as polyethylene, polyacrylate, or composite plastic films, are coated onto the surface of the corrugated cardboard box to improve its waterproof and moisture-proof properties. On the other hand, insulation layers, such as aluminum foil pearl cotton or polystyrene foam, are added inside or outside the box to enhance thermal insulation. Meanwhile, temperature monitoring in cold chain logistics is often achieved using external electronic temperature recorders or disposable temperature tags.

[0004] However, these existing technologies have significant drawbacks. The moisture-proof coating or composite film bonds firmly to the paper base material, making it difficult to separate during cardboard box recycling. This results in a large amount of plastic impurities in the pulp, reducing the quality of the recycled pulp and increasing the difficulty and cost of recycling. Furthermore, these composite cardboard boxes often cannot be easily biodegraded or composted, which is detrimental to environmental protection. In addition, existing temperature monitoring methods are also insufficient. External electronic temperature recorders are expensive and unsuitable for single-transportation use, while disposable temperature tags are mostly reversible color-changing, posing a risk of tampering. Summary of the Invention

[0005] This invention solves the problems of poor moisture-proof and heat-insulating performance and difficult recycling of ordinary corrugated cardboard boxes. It proposes a biodegradable temperature-controlled corrugated cardboard box for cold chain logistics and a recycling method, which achieves the effects of improving cold chain packaging performance, facilitating recycling and being environmentally friendly.

[0006] To achieve the above objectives, the following technical solution is proposed: A biodegradable temperature-controlled corrugated cardboard box for cold chain logistics includes a box body made of corrugated cardboard and at least one biodegradable functional composite film that is separably bonded to the outer and / or inner surfaces of the box body by a water-soluble adhesive layer. The biodegradable functional composite film comprises a hydrophobic surface layer, a phase change heat-insulating middle layer, and a hydrophilic inner layer arranged sequentially. The phase change insulation middle layer contains phase change material microcapsules, and the phase change temperature of the phase change material microcapsules is -5℃ to 15℃. An irreversible thermochromic indicator label is provided on the main body of the cardboard box or the biodegradable functional composite film.

[0007] By adopting the above technical solutions, a separable and recyclable design is achieved. The biodegradable functional composite film can be automatically separated from the cardboard box body simply by soaking in room temperature water, improving recycling efficiency and the quality of recycled pulp, and reducing recycling costs. The biodegradable functional composite film integrates multiple functions such as hydrophobicity and moisture resistance, phase change heat storage and insulation, and affinity adhesion to the paper base. The phase change material microcapsules can absorb or release heat within the cold chain temperature range, extending the time for the temperature inside the box to stabilize. The irreversible thermochromic indicator label can record whether a "chain break" event exceeding the safe temperature range has occurred during transportation, and the color change is irreversible, providing a reliable basis for product quality traceability. All major materials have biodegradable or recyclable environmental protection attributes, achieving environmental friendliness throughout the entire life cycle.

[0008] Preferably, the phase change insulating middle layer of the biodegradable functional composite film serves as the substrate, and its material is selected from at least one of polylactic acid, polybutylene adipate terephthalate, and polyhydroxyalkanoates; the hydrophobic surface layer further comprises hydrophobically modified nanocellulose; and the hydrophilic inner layer comprises hydrophilic starch or polyvinyl alcohol.

[0009] By adopting the above technical solution, at least one of polylactic acid, polybutylene adipate terephthalate, and polyhydroxyalkanoates is selected as the matrix material of the biodegradable functional composite film, giving the film biodegradable and environmentally friendly properties; the hydrophobic surface layer contains hydrophobically modified nanocellulose, which can give the film excellent waterproof and moisture-proof properties; the hydrophilic inner layer contains hydrophilic starch or polyvinyl alcohol, which can form a strong adhesive interface with the water-soluble adhesive layer, which helps to separate the biodegradable functional composite film from the carton body.

[0010] Preferably, the core material of the phase change material microcapsule is selected from at least one of paraffin wax, fatty acid, and inorganic hydrated salt, and the wall material is selected from at least one of urea-formaldehyde resin, melamine-formaldehyde resin, and polymethyl methacrylate; the mass fraction of the phase change material microcapsule in the phase change insulation middle layer is 10%-40%.

[0011] By adopting the above technical solutions, the specific core and wall materials of phase change material microcapsules, combined with their mass fraction of 10%-40% in the middle layer of phase change insulation, can absorb or release heat within the cold chain temperature range, thereby playing a role in passive temperature control and extending the insulation time.

[0012] Preferably, the irreversible thermochromic indicator label includes a paper substrate and at least one thermochromic unit disposed on the paper substrate; The thermochromic unit includes a first thermochromic region and a second thermochromic region; The first thermochromic region undergoes an irreversible color change after being heated to a temperature above a preset first threshold. The second thermochromic region undergoes an irreversible color change after being heated to a temperature above a preset second temperature threshold, and the first temperature threshold is lower than the second temperature threshold.

[0013] By adopting the above technical solution, the first and second thermochromic areas of the irreversible thermochromic indicator label can undergo irreversible color changes after being heated above the preset first and second temperature thresholds, respectively. The first temperature threshold is lower than the second temperature threshold. This can record whether a "chain break" event exceeding the safe temperature range has occurred during transportation. The color change is irreversible, preventing the results from being tampered with and providing a reliable basis for product quality traceability.

[0014] Preferably, the first temperature threshold is 0-10℃, and the second temperature threshold is 15-25℃; the irreversible thermochromic indicator label also includes a reference colorimeter, which is printed with standard colors corresponding to the first thermochromic region and the second thermochromic region in the uncolored state and the fully colored state.

[0015] By adopting the above technical solution, setting the first temperature threshold to 0-10℃ and the second temperature threshold to 15-25℃, it is possible to more accurately record different degrees of temperature exceeding the standard "chain breakage" events during cold chain transportation; equipped with a reference color chart printed with standard colors of the first and second thermochromic areas in their uncolored and fully colored states, it is convenient for users to intuitively and accurately determine whether situations exceeding the safe temperature range have occurred during transportation, providing a more reliable basis for product quality traceability. At the same time, combined with other technical means in claims 1 and 4, the separable and recyclable design realizes efficient and clean separation of different materials, improves recycling efficiency and quality, and reduces costs; the biodegradable functional composite film integrates multiple functions such as hydrophobic moisture-proofing, phase change heat storage and insulation.

[0016] Preferably, the water-soluble adhesive layer is selected from one or more of polyvinyl alcohol adhesive, polyethylene oxide adhesive, sodium carboxymethyl cellulose adhesive, or water-soluble polyurethane adhesive; the water-soluble adhesive layer dissolves in water at 20-40°C for no more than 5 minutes.

[0017] By adopting the above technical solution, one or more of polyvinyl alcohol adhesive, polyethylene oxide adhesive, sodium carboxymethyl cellulose adhesive, or water-soluble polyurethane adhesive are selected as the water-soluble adhesive layer. The adhesive layer dissolves in water at 20-40℃ for no more than 5 minutes. In the recycling process after use, the biodegradable functional composite film can be automatically separated from the cardboard box body simply by soaking in room temperature water. This achieves efficient and clean separation of different materials, greatly improving recycling efficiency and the quality of recycled pulp, and reducing recycling costs.

[0018] Preferably, the corrugated cardboard of the carton body includes a face paper layer, a corrugated core layer and a liner paper layer, wherein at least one layer contains hydrophobically modified starch or alkyl ketene dimer.

[0019] By adopting the above technical solutions, the main body of the cardboard box has basic moisture-proof performance, which can prevent the cardboard box from getting damp and softening to a certain extent, ensuring its strength and better protecting the contents.

[0020] A method for recycling biodegradable temperature-controlled corrugated cardboard boxes as described above includes the following steps: S1: Immerse the used corrugated cardboard box entirely in room temperature water for 1-30 minutes to dissolve the water-soluble adhesive layer; S2: Stirring or rinsing to completely separate the biodegradable functional composite film from the carton body; S3: Separate the biodegradable functional composite film from the pulp by filtration or sieving, and collect the pulp and film fragments separately; S4: Recycle the collected pulp using conventional papermaking processes; compost or recycle the collected film fragments into plastic pellets.

[0021] By adopting the above technical solutions, efficient and clean separation of different materials in biodegradable temperature-controlled corrugated cardboard boxes can be achieved, greatly improving recycling efficiency and the quality of recycled pulp, and reducing recycling costs. The recycled pulp can be used for recycled paper production, and the film fragments can be used for composting or plastic reprocessing, achieving environmental friendliness throughout the entire life cycle.

[0022] Preferably, step S1 is further aided by ultrasonic oscillation or mechanical stirring.

[0023] By adopting the above technical solution, when recycling biodegradable temperature-controlled corrugated boxes, ultrasonic oscillation or mechanical stirring can be used as an adjunct to the room temperature water soaking step to accelerate the dissolution of the water-soluble adhesive layer and the separation of the biodegradable functional composite film, thereby improving the efficiency of the recycling process.

[0024] Preferably, a pH adjuster or surfactant is added to the room temperature water.

[0025] By adopting the above technical solution, adding pH adjusters or surfactants to room temperature water can promote the dissolution of water-soluble adhesive layers or the dispersion of films, making it easier to separate the biodegradable functional composite film from the cardboard box body. This improves the efficiency of each step in the biodegradable temperature-controlled corrugated cardboard box recycling method and ensures the smooth progress of the recycling work.

[0026] The beneficial effects of this invention are: 1. A water-soluble adhesive is used to bond the biodegradable functional composite film to the cardboard box body in a separable manner. After use, the two can be automatically separated by soaking in room temperature water, which improves recycling efficiency and the quality of recycled pulp, and reduces recycling costs. 2. Biodegradable functional composite films integrate multiple functions such as hydrophobicity and moisture resistance, phase change heat storage and insulation, and affinity adhesion to paper substrates; 3. Phase change material microcapsules can absorb or release heat within the cold chain temperature range, extending the time for temperature stabilization inside the box. Irreversible thermochromic indicator labels can record "chain break" events during transportation, and the color change is irreversible, providing a reliable basis for product quality traceability. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view of the corrugated cardboard of the present invention.

[0028] Figure 2 This is a schematic diagram of the structure of the irreversible thermochromic indicator label of the present invention.

[0029] Figure 3 This is a flowchart of the recycling method of the present invention.

[0030] The components include: 1. Corrugated cardboard; 11. Face paper layer; 12. Corrugated core layer; 13. Inner paper layer; 2. Water-soluble adhesive layer; 3. Biodegradable functional composite film; 31. Hydrophobic surface layer; 32. Phase change insulation middle layer; 321. Phase change material microcapsules; 3211. Core material; 3212. Wall material; 33. Hydrophilic inner layer; 4. Irreversible thermochromic indicator label; 41. Paper substrate; 42. First thermochromic area; 43. Second thermochromic area; 44. Reference colorimetric card. Detailed Implementation Example

[0031] This embodiment proposes a biodegradable temperature-controlled corrugated cardboard box for cold chain logistics, referencing... Figure 1 The carton body is made of corrugated cardboard 1 and at least one biodegradable functional composite film 3 is detachably bonded to the outer and / or inner surfaces of the carton body by a water-soluble adhesive layer 2. The biodegradable functional composite film 3 includes a hydrophobic surface layer 31, a phase change heat-insulating middle layer 32, and a hydrophilic inner layer 33 arranged sequentially. The phase change insulation middle layer 32 contains phase change material microcapsules 321, and the phase change temperature of the phase change material microcapsules 321 is -5℃ to 15℃. An irreversible thermochromic indicator label 4 is provided on the carton body or the biodegradable functional composite film 3.

[0032] This embodiment achieves a separable and recyclable design. The biodegradable functional composite film 3 can be automatically separated from the cardboard box body simply by soaking in room temperature water, improving recycling efficiency and the quality of recycled pulp, and reducing recycling costs. The biodegradable functional composite film 3 integrates multiple functions such as hydrophobicity and moisture resistance, phase change heat storage and insulation, and affinity adhesion to the paper base. The phase change material microcapsules 321 can absorb or release heat within the cold chain temperature range, extending the time for the temperature inside the box to stabilize. The irreversible thermochromic indicator label 4 can record whether a "chain break" event exceeding the safe temperature range has occurred during transportation, and the color change is irreversible, providing a reliable basis for product quality traceability. All major materials have biodegradable or recyclable environmental protection attributes, achieving environmental friendliness throughout the entire life cycle.

[0033] The phase change insulating middle layer 32 of the biodegradable functional composite film 3 serves as the substrate, and its material is selected from at least one of polylactic acid, polybutylene adipate terephthalate, and polyhydroxyalkanoates; the hydrophobic surface layer 31 further comprises hydrophobically modified nanocellulose; and the hydrophilic inner layer 33 comprises hydrophilic starch or polyvinyl alcohol.

[0034] In this embodiment, at least one of polylactic acid, polybutylene adipate terephthalate, and polyhydroxyalkanoates is selected as the matrix material of the biodegradable functional composite film 3, giving the film biodegradable and environmentally friendly properties; the hydrophobic surface layer 31 contains hydrophobically modified nanocellulose, which can give the film excellent waterproof and moisture-proof properties; the hydrophilic inner layer 33 contains hydrophilic starch or polyvinyl alcohol, which can form a strong adhesive interface with the water-soluble adhesive layer 2, which helps to separate the biodegradable functional composite film 3 from the carton body.

[0035] The core material 3211 of the phase change material microcapsule 321 is selected from at least one of paraffin, fatty acid, and inorganic hydrated salt, and the wall material 3212 is selected from at least one of urea-formaldehyde resin, melamine-formaldehyde resin, and polymethyl methacrylate; the mass fraction of the phase change material microcapsule 321 in the phase change insulation middle layer 32 is 10%-40%.

[0036] In this embodiment, the specific selection of core material 3211 and wall material 3212 of the phase change material microcapsule 321, combined with its mass fraction of 0%-40% in the phase change insulation middle layer 321, can absorb or release heat within the cold chain temperature range, thereby playing a role in passive temperature control and extending the insulation time.

[0037] The fabrication process of the biodegradable functional composite film 3 is as follows: The hydrophobic surface layer material (PLA + hydrophobically modified nanocellulose), the phase change insulating middle layer material (PBAT + phase change material microcapsules), and the hydrophilic inner layer material (PLA + starch) are respectively fed into three extruders. The materials are heated to a molten state (approximately 170-190℃) in the three extruders. The melt simultaneously enters the three-layer co-extrusion die and flows out according to the predetermined layer thickness ratio. The molten three layers come into direct contact and thermally bonded within the die or immediately after exiting the die. After cooling and shaping by cooling rollers, a three-layer composite film is obtained. The manufacturing process requires no additional adhesives, is environmentally friendly, has high interlayer bonding strength, is not prone to delamination, and can be continuously produced with high efficiency.

[0038] The irreversible thermochromic indicator label 4 includes a paper substrate 41 and at least one thermochromic unit disposed on the paper substrate 41; The thermochromic unit includes a first thermochromic region 42 and a second thermochromic region 43; The first thermochromic region 42 undergoes an irreversible color change after being heated to a temperature above a preset first temperature threshold. The second thermochromic region 43 undergoes an irreversible color change after being heated to a temperature above a preset second temperature threshold, and the first temperature threshold is lower than the second temperature threshold.

[0039] In this embodiment, the first thermochromic area 42 and the second thermochromic area 43 of the irreversible thermochromic indicator label 4 can undergo irreversible color changes after being heated above the preset first and second temperature thresholds, respectively. The first temperature threshold is lower than the second temperature threshold. This can record whether a "chain break" event exceeding the safe temperature range has occurred during transportation. The color change is irreversible, preventing the results from being tampered with and providing a reliable basis for product quality traceability.

[0040] The thermochromic unit adopts an organic electron transfer microcapsule system, with the core structure as follows: Color-generating agent electron donor: usually a leuco dye, such as crystal violet lactone, etc.; Electron acceptors for colorimetric reagents: such as phenolic compounds like bisphenol A; Temperature control agent / solvent: An organic medium that determines the color change temperature; These three components are encapsulated within the same particle using microencapsulation technology, stored independently, and do not react at room temperature. When the temperature reaches a set threshold, the environment inside the microcapsule changes, causing an electron transfer reaction between the chromophore and the developer, resulting in an irreversible change in the dye molecule structure and thus a color change.

[0041] The first temperature threshold is 0-10℃, and the second temperature threshold is 15-25℃; Reference Figure 2 The irreversible thermochromic indicator label 4 also includes a reference colorimeter card 44, which is printed with standard colors corresponding to the first thermochromic region 42 and the second thermochromic region 43 in the uncolored state and the fully colored state.

[0042] This embodiment sets the first temperature threshold to 0-10℃ and the second temperature threshold to 15-25℃, enabling more accurate recording of different degrees of temperature exceeding the limit and "chain breakage" events during cold chain transportation. It is equipped with a reference color chart 44 printed with standard colors for the first and second thermochromic areas (unchanged and fully changed), facilitating users to intuitively and accurately determine whether temperatures exceeding the safe range have occurred during transportation, providing a more reliable basis for product quality traceability. Simultaneously, combined with other technical means in claims 1 and 4, the separable and recyclable design achieves efficient and clean separation of different materials, improving recycling efficiency and quality while reducing costs. The biodegradable functional composite film 3 integrates multiple functions such as hydrophobicity, moisture resistance, and phase change heat storage. The phase change material microcapsules 321 can absorb or release heat within the cold chain temperature range, extending the temperature stabilization time inside the box. The first thermochromic area 42 uses thermochromic ink that irreversibly changes from green to yellow after being exposed to temperatures above 8℃ for more than 30 minutes; the second thermochromic area 43 uses thermochromic ink that irreversibly changes from green to red after being exposed to temperatures above 25℃ for more than 30 minutes. The label also includes a reference color chart, displaying standard colors for green (no color change), yellow (first area has changed color, indicating a temperature above 8°C), and red (second area has changed color, indicating a temperature above 25°C), facilitating visual interpretation. The thermochromic ink of this invention forms a solid-liquid phase change system within microcapsules by selecting temperature-regulating agents (such as specific alcohols, esters, or long-chain alkanes) with specific melting points (e.g., 8°C, 25°C). When the temperature exceeds this threshold, the solvent melts, allowing the color-developing agent and the color-fixing agent to come into contact and undergo an irreversible electron transfer reaction, thus lowering the color-changing temperature to 8-25°C.

[0043] The water-soluble adhesive layer 2 is selected from one or more of polyvinyl alcohol adhesive, polyethylene oxide adhesive, sodium carboxymethyl cellulose adhesive, or water-soluble polyurethane adhesive; the water-soluble adhesive layer 2 dissolves in water at 20-40°C for no more than 5 minutes.

[0044] In this embodiment, one or more of polyvinyl alcohol adhesive, polyethylene oxide adhesive, sodium carboxymethyl cellulose adhesive, or water-soluble polyurethane adhesive are selected as the water-soluble adhesive layer 2. The adhesive layer dissolves in water at 20-40°C for no more than 5 minutes. In the recycling process after use, the biodegradable functional composite film 3 can be automatically separated from the cardboard box body simply by soaking in room temperature water. This achieves efficient and clean separation of different materials, greatly improving recycling efficiency and the quality of recycled pulp, and reducing recycling costs.

[0045] The corrugated cardboard 1 of the carton body includes a face paper layer 11, a corrugated core layer 12 and a liner paper layer 13, wherein at least one layer contains hydrophobically modified starch or alkyl ketene dimer to give the carton body basic moisture-proof properties.

[0046] This embodiment enables the cardboard box body to have basic moisture-proof performance, which can prevent the cardboard box from getting damp and softening to a certain extent, ensuring its strength and better protecting the contents.

[0047] The implementation principle of this embodiment is as follows: the moisture-proof treatment of the cardboard box body and the multi-functional design of the biodegradable functional composite film improve the moisture-proof and heat-insulating performance of the cardboard box; the use of a water-soluble adhesive layer enables efficient material separation during recycling, reducing recycling costs and improving the quality of recycled pulp; the irreversible thermochromic indicator label provides a reliable means of temperature monitoring during cold chain transportation, and the irreversible color change prevents tampering with the results, providing strong evidence for product quality traceability. Adjusting the temperature threshold of the irreversible thermochromic indicator label to better meet specific transportation requirements enables more accurate monitoring of temperature changes during cold chain transportation, ensuring the quality and safety of the contents. Simultaneously, all major materials possess biodegradable or recyclable environmental properties, achieving environmental friendliness throughout the entire life cycle. Example

[0048] This embodiment proposes a recycling method for biodegradable temperature-controlled corrugated cardboard boxes as described above, based on Embodiment 1. (Refer to...) Figure 3 This includes the following steps: S1: Immerse the used corrugated cardboard box entirely in room temperature water for 1-30 minutes to dissolve the water-soluble adhesive layer 2. Step S1 is further aided by ultrasonic oscillation or mechanical stirring to accelerate the dissolution of the water-soluble adhesive layer 2 and the separation of the film. A pH adjuster or surfactant is also added to the room temperature water to promote the dissolution of the water-soluble adhesive layer 2 or the dispersion of the film.

[0049] S2: Stirring or rinsing to completely separate the biodegradable functional composite film 3 from the carton body; S3: Separate the biodegradable functional composite film 3 from the pulp by filtration or sieving, and collect the pulp and film fragments separately; S4: The collected pulp is recycled using conventional papermaking processes; the collected film fragments are composted or recycled into plastic granules. The film material is biodegradable, and under industrial composting conditions, more than 90% can be degraded within 6 months.

[0050] This embodiment enables efficient and clean separation of different materials in biodegradable temperature-controlled corrugated cardboard boxes, greatly improving recycling efficiency and pulp quality while reducing recycling costs. The recycled pulp can be used for recycled paper production, and the film fragments can be used for composting or plastic reprocessing, achieving environmental friendliness throughout the entire lifecycle. During the recycling of biodegradable temperature-controlled corrugated cardboard boxes, ultrasonic oscillation or mechanical stirring during the room-temperature water soaking step accelerates the dissolution of the water-soluble adhesive layer 2 and the separation of the biodegradable functional composite film 3, improving the efficiency of the recycling process.

[0051] Adding a pH adjuster or surfactant to room temperature water can promote the dissolution of the water-soluble adhesive layer 2 or the dispersion of the film, making it easier to separate the biodegradable functional composite film 3 from the carton body. This improves the efficiency of each step in the recycling method of biodegradable temperature-controlled corrugated cardboard boxes and ensures the smooth progress of the recycling work.

[0052] The implementation principle of this embodiment is as follows: This recycling method utilizes the characteristics of the water-soluble adhesive layer, and through simple soaking, stirring, and separation operations, achieves efficient separation of the biodegradable functional composite film from the cardboard box body. The recycled pulp and film fragments can be rationally utilized, reducing recycling costs and environmental pollution, aligning with environmental protection principles, and also solving the problem of difficult recycling of existing composite cardboard boxes.

[0053] Comparative Examples 1 and 2 were set up to verify the effects of Examples 1 and 2: Comparative Example 1: The difference between this comparative example and Example 1 is that the biodegradable functional composite film 3 is bonded to the outer surface of the carton body 1 by ordinary acrylic pressure-sensitive adhesive.

[0054] Comparative Example 2: The difference between this comparative example and Example 1 is that no phase change material microcapsules 321 are added to the phase change insulation middle layer 32 of the biodegradable functional composite film 3.

[0055] The corrugated boxes of Examples 1-2 and Comparative Examples 1-2 were subjected to the following performance tests: 1. Waterproof performance test: Cobb value test was conducted according to GB / T 22895-2008 "Determination of water absorption of paper and paperboard surfaces". The surface Cobb value (60 seconds) of Example 1 was less than 15 g / m², which is far superior to ordinary cardboard boxes without a waterproof coating (about 80 g / m²).

[0056] 2. Thermal Insulation Performance Test: The cardboard box was sealed and placed in an environment of -10℃, with a temperature recorder inside. The time required for the temperature inside the box to rise from the initial 5℃ to 15℃ was recorded. Example 1 took approximately 3.5 hours, Example 2 took approximately 4.2 hours, while Comparative Example 2 (without PCM) took only approximately 2.0 hours. The results show that the phase change insulation middle layer of the present invention significantly extends the thermal insulation time.

[0057] 3. Recyclability Test: Cut the used cardboard box into 10cm×10cm samples, immerse them in 25℃ clean water for 10 minutes, and stir slowly at 100rpm. Observe and record the membrane separation.

[0058] 4. Temperature Indication Function Test: A cardboard box with an irreversible thermochromic indicator label was placed in an 8°C environment for 2 hours. The first thermochromic area showed no color change. The temperature was then raised to 25°C and maintained for 1 hour. The first thermochromic area turned yellow, and the second thermochromic area turned red. After cooling to 5°C, the colors did not revert. This proves that the label can irreversibly record temperature exceedance events.

[0059] Examples 1 and 2: Within 3-5 minutes, the functional composite film begins to curl up from the edge of the cardboard and gradually detaches; after 8-10 minutes, the film completely separates from the cardboard. The pulp fibers obtained after filtration are pure, with no obvious plastic residue; the separated film remains intact.

[0060] Comparative Example 1: After soaking for 30 minutes, the functional composite film remained tightly bonded to the cardboard and could not be separated naturally, requiring external force to tear it. After tearing, residual adhesive and paper fibers remained on the surface of the cardboard.

[0061] The results show that the separable design of the present invention greatly simplifies the recycling process and achieves clean separation of materials.

[0062] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A degradable temperature-controlled corrugated carton for cold chain logistics, characterized in that, The carton body is made of corrugated cardboard (1) and at least one biodegradable functional composite film (3) is detachably bonded to the outer and / or inner surfaces of the carton body by a water-soluble adhesive layer (2). The biodegradable functional composite film (3) includes a hydrophobic surface layer (31), a phase change heat insulation middle layer (32), and a hydrophilic inner layer (33) arranged sequentially. The phase change insulation middle layer (32) contains phase change material microcapsules (321), and the phase change temperature of the phase change material microcapsules (321) is -5℃ to 15℃; An irreversible thermochromic indicator label (4) is provided on the carton body or the biodegradable functional composite film (3).

2. The biodegradable temperature-controlled corrugated cardboard box for cold chain logistics according to claim 1, characterized in that, The phase change insulating middle layer (32) of the biodegradable functional composite film (3) is used as the matrix, and its material is selected from at least one of polylactic acid, polybutylene adipate terephthalate, and polyhydroxy fatty acid ester; the hydrophobic surface layer (31) also contains hydrophobically modified nanocellulose; the hydrophilic inner layer (33) contains hydrophilic starch or polyvinyl alcohol.

3. A biodegradable temperature-controlled corrugated cardboard box for cold chain logistics according to claim 1, characterized in that, The core material (3211) of the phase change material microcapsule (321) is selected from at least one of paraffin, fatty acid, and inorganic hydrated salt, and the wall material (3212) is selected from at least one of urea-formaldehyde resin, melamine-formaldehyde resin, and polymethyl methacrylate; the mass fraction of the phase change material microcapsule (321) in the phase change insulation middle layer (32) is 10%-40%.

4. A biodegradable temperature-controlled corrugated cardboard box for cold chain logistics according to claim 1, characterized in that, The irreversible thermochromic indicator label (4) includes a paper substrate (41) and at least one thermochromic unit disposed on the paper substrate (41); The thermochromic unit includes a first thermochromic region (42) and a second thermochromic region (43). The first thermochromic region (42) undergoes an irreversible color change after being heated above a preset first temperature threshold. The second thermochromic region (43) undergoes an irreversible color change after being heated to a temperature above a preset second temperature threshold, and the first temperature threshold is lower than the second temperature threshold.

5. A biodegradable temperature-controlled corrugated cardboard box for cold chain logistics according to claim 4, characterized in that, The first temperature threshold is 0-10℃, and the second temperature threshold is 15-25℃; the irreversible thermochromic indicator label (4) also includes a reference colorimeter (44), which is printed with standard colors corresponding to the first thermochromic region (42) and the second thermochromic region (43) in the uncolored state and the fully colored state.

6. A biodegradable temperature-controlled corrugated cardboard box for cold chain logistics according to claim 1, characterized in that, The water-soluble adhesive layer (2) is selected from one or more of polyvinyl alcohol adhesive, polyethylene oxide adhesive, sodium carboxymethyl cellulose adhesive or water-soluble polyurethane adhesive; the water-soluble adhesive layer (2) dissolves in water at 20-40°C for no more than 5 minutes.

7. A biodegradable temperature-controlled corrugated cardboard box for cold chain logistics according to claim 1, characterized in that, The corrugated cardboard (1) of the carton body includes a face paper layer (11), a corrugated core layer (12) and a liner paper layer (13), wherein at least one layer contains hydrophobically modified starch or alkyl ketene dimer.

8. A method for recycling biodegradable temperature-controlled corrugated cardboard boxes for cold chain logistics, wherein the biodegradable temperature-controlled corrugated cardboard boxes for cold chain logistics as described in any one of claims 1-7 are recycled, characterized in that, Includes the following steps: S1: Immerse the used corrugated cardboard box in room temperature water for 1-30 minutes to dissolve the water-soluble adhesive layer (2); S2: Stir or rinse to completely separate the biodegradable functional composite film (3) from the carton body; S3: Separate the biodegradable functional composite film (3) from the pulp by filtration or sieving, and collect the pulp and film fragments respectively; S4: Recycle the collected pulp using conventional papermaking processes; compost or recycle the collected film fragments into plastic pellets.

9. A method for recycling biodegradable temperature-controlled corrugated cardboard boxes for cold chain logistics according to claim 8, characterized in that, In step S1, ultrasonic oscillation or mechanical stirring is also used as an auxiliary method.

10. A method for recycling biodegradable temperature-controlled corrugated cardboard boxes for cold chain logistics according to claim 8, characterized in that, The room temperature water also contains pH adjusters or surfactants.

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