A method of separating a food packaging composite article

Abstract

The present application relates to a kind of food packaging composite material separation method, belong to the technical field of recycling method.The food packaging composite material separation method includes raw material conveying and cleaning, initial kneading separation, pulp purification and recovery, aluminum plastic purification and recovery, aluminum plastic semi-separation treatment, reagent recovery and secondary kneading preparation and aluminum plastic final separation and processing.The food packaging composite material separation method provided by the present application, for the technical problems that aluminum plastic and paper layer cannot be effectively separated, resources are wasted seriously, and environmental pollution is prominent when milk product packaging box is recycled in the prior art paper, aluminum film and plastic film composite, through multi-step cooperation, the efficient, thorough separation of each component of food packaging composite material is realized.

Description

Technical Field

[0001] This invention relates to the technical field of recycling methods, and specifically to a method for separating materials used in food packaging composite products. Background Technology

[0002] In the food packaging industry, dairy product packaging boxes (commonly known as "milk boxes") are widely used for packaging various dairy products such as milk, yogurt, and milk beverages due to their advantages such as being lightweight, having excellent sealing performance, and effectively extending the shelf life of dairy products. They are currently one of the most mainstream composite material types for food packaging. These milk boxes typically employ a multi-layered structure composed of paper, aluminum film, and plastic film. The paper layer primarily serves to provide support and shape, the aluminum film blocks oxygen and light to prevent oxidation and spoilage of the dairy products, and the plastic film is responsible for sealing and waterproofing, ensuring the airtightness and integrity of the packaging. These three layers are tightly combined through a composite process to jointly achieve the protective function for the dairy products.

[0003] With the increasing consumption of dairy products year by year, the amount of discarded milk cartons has also increased significantly, becoming one of the main solid wastes in household waste. However, due to the composite structure of milk cartons, traditional recycling processes face the technical challenge of effectively separating the aluminum film, plastic film, and paper layer. Currently, traditional recycling methods mostly employ simple crushing, landfilling, or incineration, which cannot achieve the separate recycling and reuse of each component.

[0004] This extensive approach to waste disposal not only results in serious resource waste—paper, aluminum, and plastic are all recyclable resources, with aluminum being a non-renewable resource with extremely high recycling value, and plastic film and paper layers can also be recycled and reused, but the unseparated composite waste cannot be effectively utilized and is simply wasted; at the same time, landfill disposal occupies a large amount of land resources, and composite materials are difficult to degrade, easily causing environmental pollution to soil and groundwater, while incineration produces harmful gases and damages the atmospheric environment, which is inconsistent with the current development concept of green environmental protection and resource recycling.

[0005] Therefore, the existing milk carton recycling methods suffer from problems such as difficulty in separating aluminum and plastic, low resource utilization, and serious environmental pollution. These problems have become key bottlenecks restricting the development of the dairy product packaging box recycling industry. There is an urgent need for a technology that can achieve efficient separation of paper, aluminum film, and plastic film in milk cartons to solve the defects of traditional methods, improve resource recycling rate, and reduce environmental pollution. Summary of the Invention

[0006] To address the technical problem that traditional methods for recycling dairy product packaging boxes cannot effectively separate the aluminum-plastic composite from the paper layer, leading to resource waste and environmental pollution, this invention provides a method for separating composite materials in food packaging to solve the aforementioned problems. The method for separating composite materials in food packaging provided by this invention addresses the technical challenge of existing technologies that fail to effectively separate the aluminum-plastic composite from the paper layer during the recycling of dairy product packaging boxes made of paper, aluminum film, and plastic film, resulting in significant resource waste and environmental pollution. Through multi-step coordinated processes, it achieves efficient and thorough separation of the various components of the composite material in food packaging.

[0007] The technical solution of this invention is as follows: A method for separating materials in food packaging composite products includes the following steps: (1) Raw material conveying and cleaning: The raw materials of food packaging composite products are conveyed to the cleaning machine for cleaning. After cleaning, the raw materials are conveyed to the kneading machine. (2) Initial kneading and separation: The washed raw materials are kneaded by a kneading machine to separate the raw materials into pulp and aluminum-plastic mixture; (3) Pulp purification and recycling: The pulp obtained in step (2) is sent to a press and screened by the press to separate the pulp into pure pulp and trace aluminum-plastic mixture; the pure pulp is sent to a filter press for filter treatment, and after filter treatment, it is packaged; the trace aluminum-plastic mixture is recycled back into the aluminum-plastic mixture separated by the rubbing machine in step (2) for recycling. (4) Aluminum-plastic purification and recycling: The aluminum-plastic mixture obtained in step (2) is sent to a cleaning machine for secondary cleaning. The aluminum-plastic mixture is separated into pure aluminum-plastic mixture and trace pulp through cleaning. The pure aluminum-plastic mixture is sent to a reaction chamber. The trace pulp is recycled back to the pulp separated by the kneading machine in step (2) for recycling. (5) Semi-separation treatment of aluminum and plastic: Add a separating agent to the reaction chamber to treat the pure aluminum and plastic mixture, so that the aluminum and plastic mixture forms a semi-separated pleated state. After the treatment is completed, it is transported to the extruder. (6) Recycling of reagents and preparation for secondary kneading: The aluminum-plastic mixture in a semi-separated state is squeezed dry by a squeeze dryer, and the reagent squeezed out during the squeezing process is recycled to the reaction chamber in step (5) for reuse; after squeezing dry, the aluminum-plastic mixture is transported to kneading machine B; (7) Final separation and treatment of aluminum and plastic: The aluminum-plastic mixture after squeezing is kneaded by kneading machine B to separate it into plastic and aluminum; the plastic is sent to rinsing machine A for rinsing, and after rinsing, it is sent to granulation device; the aluminum is sent to rinsing machine B for rinsing, and after rinsing, it is sent to dryer for drying, and after drying, it is packaged.

[0008] Furthermore, in step (1), the raw material for the food packaging composite product is a dairy product packaging box made of paper, aluminum film and plastic film.

[0009] Furthermore, in step (1), the cleaning temperature of the cleaning machine is 30~50℃, the cleaning time is 10~20min, and a neutral cleaning agent is added during the cleaning process to remove residual dairy products and impurities from the surface of the raw materials.

[0010] Furthermore, in step (2), the kneading speed of the kneading machine is 150~250 r / min and the kneading time is 8~15 min, to ensure that the raw materials are fully separated into pulp and aluminum-plastic mixture, and that the pulp has no obvious large solid impurities.

[0011] Furthermore, in step (3), the extrusion pressure of the press is 0.3~0.6MPa, the screening aperture is 50~80 mesh, and the pure pulp and trace aluminum-plastic mixture are completely separated by extrusion screening. The purity of the pure pulp is not less than 98%.

[0012] Furthermore, in step (4), the cleaning time for the second cleaning is 5~10 minutes, the cleaning temperature is 25~35℃, and the pulp content in the pure aluminum-plastic mixture after cleaning does not exceed 0.5%.

[0013] Furthermore, in step (5), the separating agent comprises the following components by mass percentage: citric acid: 3.0wt%~6.0wt%, oxalic acid: 0.5wt%~1.5wt%, fatty alcohol polyoxyethylene ether (AEO-9): 0.1wt%~0.3wt%, with the balance being water. Citric acid and oxalic acid form a mixed organic acid system that can gently complex and corrode the oxide layer on the surface of the aluminum foil and disrupt the molecular structure of the adhesive (usually polyurethane or polyethylene) between the aluminum foil and polyethylene; AEO-9, as a nonionic surfactant, promotes the penetration of the acid solution into the interface and disperses the stripping products.

[0014] Furthermore, in step (5), the amount of separating agent added is 5% to 10% of the mass of the pure aluminum-plastic mixture, the processing temperature in the reaction chamber is 40 to 60°C, and the processing time is 20 to 30 minutes, to ensure that the aluminum-plastic mixture forms a uniform wrinkled semi-separated state.

[0015] Furthermore, in step (6), the squeezing pressure of the squeezing machine is 0.2~0.4MPa, the moisture content of the aluminum-plastic mixture after squeezing does not exceed 15%, and the recovered reagent is filtered and then transported to the reaction chamber for recycling.

[0016] Furthermore, in step (7), the kneading speed of the kneading machine B is 200~300 r / min, and the kneading time is 10~20 min; the rinsing time of both the rinsing machine A and the rinsing machine B is 5~8 min, and there are no residual agents or impurities on the surface of the plastic and aluminum after rinsing; the drying temperature of the dryer is 80~100℃, the drying time is 15~25 min, and the moisture content of the aluminum after drying does not exceed 2%.

[0017] The beneficial effects of this invention are as follows: The method for separating food packaging composite materials provided by this invention achieves efficient separation and recycling of each component, significantly improving resource utilization. It solves the pain point of traditional methods being unable to separate aluminum-plastic and paper layers and only able to process them in a crude manner. The method separates food packaging composite materials into three recyclable resources: pure pulp, plastic, and aluminum. Pure pulp can be directly packaged and reused, plastic can be further processed after rinsing and granulation, and aluminum can be directly recycled after rinsing and drying. This fully realizes the recycling of resources and avoids the waste of resources such as paper, aluminum, and plastic, especially improving the recycling efficiency of non-renewable aluminum resources.

[0018] This invention employs a multi-stage purification and recycling design to effectively improve separation purity. The pulp is purified by pressing and screening, and the aluminum-plastic mixture is purified by secondary cleaning in a washing machine. At the same time, trace amounts of aluminum-plastic and pulp generated during the separation process are recycled to the corresponding steps for recycling, ensuring the purity of pure pulp and pure aluminum-plastic mixture, thereby guaranteeing the quality of the final separated plastic and aluminum and meeting the requirements for subsequent recycling.

[0019] This invention also enables the recycling of the separating agent, reducing method costs and environmental pollution. The reagent extruded by the squeeze dryer is recycled and transported back to the reaction chamber for reuse, reducing the consumption of the separating agent and lowering the process operating costs. At the same time, it avoids soil and water pollution caused by the random discharge of reagents. In addition, the entire process generates no harmful gases and emits no waste that is difficult to degrade, replacing the traditional extensive treatment methods of landfill and incineration, which is in line with the development concept of green environmental protection and resource recycling. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0021] Example 1 A method for separating materials in food packaging composite products, comprising the following specific steps: (1) Raw material conveying and cleaning: The paper, aluminum film and plastic film composite dairy product packaging box is used as raw material and conveyed to the cleaning machine for cleaning treatment; the cleaning temperature of the cleaning machine is 30℃ and the cleaning time is 10min. Neutral cleaning agent is added during the cleaning process to remove residual dairy products and impurities on the surface of the raw material; after cleaning, the raw material is conveyed to the kneading machine.

[0022] (2) Initial kneading and separation: The cleaned raw materials are kneaded by a kneading machine at a speed of 150 r / min and a kneading time of 8 min to ensure that the raw materials are fully separated into pulp and aluminum-plastic mixture, and that the pulp has no obvious large solid impurities.

[0023] (3) Pulp purification and recycling: The pulp obtained in step (2) is transported to a press with a pressing pressure of 0.3 MPa and a screening aperture of 50 mesh. Through the pressing and screening process, the pulp is separated into pure pulp with a purity of not less than 98% and a trace aluminum-plastic mixture. The pure pulp is transported to a filter press for filtration. After filtration, it is packaged. The trace aluminum-plastic mixture is recycled back into the aluminum-plastic mixture separated by the kneading machine in step (2) for recycling.

[0024] (4) Aluminum-plastic purification and recycling: The aluminum-plastic mixture obtained in step (2) is sent to a cleaning machine for secondary cleaning. The cleaning time for the secondary cleaning is 5 minutes and the cleaning temperature is 25°C. The aluminum-plastic mixture is separated into a pure aluminum-plastic mixture with a pulp content of no more than 0.5% and a trace amount of pulp through cleaning. The pure aluminum-plastic mixture is sent to a reaction chamber. The trace amount of pulp is recycled back to the pulp separated by the kneading machine in step (2) for recycling.

[0025] (5) Semi-separation treatment of aluminum and plastic: Add a separating agent to the reaction chamber. The separating agent includes the following components by mass percentage: citric acid: 3.0 wt%, oxalic acid: 0.5 wt%, fatty alcohol polyoxyethylene ether (AEO-9): 0.1 wt%, and the balance is water. The amount of separating agent added is 5% of the mass of the pure aluminum-plastic mixture. The treatment temperature in the reaction chamber is 40°C and the treatment time is 20 min, so that the aluminum-plastic mixture forms a uniform wrinkled semi-separation state. After the treatment is completed, it is transported to the extruder.

[0026] (6) Recycling of reagents and preparation for secondary kneading: The aluminum-plastic mixture in a semi-separated state is squeezed dry by a squeeze dryer with a squeezing pressure of 0.2 MPa. The moisture content of the aluminum-plastic mixture after squeezing does not exceed 15%. The reagents squeezed out during the squeezing process are filtered and recycled to the reaction chamber in step (5) for reuse. After squeezing, the aluminum-plastic mixture is transported to kneading machine B.

[0027] (7) Final separation and treatment of aluminum and plastic: The aluminum-plastic mixture after extrusion is kneaded by kneading machine B. The kneading speed of kneading machine B is 200 r / min and the kneading time is 10 min, which separates it into plastic and aluminum. The plastic is sent to rinsing machine A for rinsing treatment. The rinsing time is 5 min. After rinsing, it is sent to the granulation device. The aluminum is sent to rinsing machine B for rinsing treatment. The rinsing time is 5 min. After rinsing, it is sent to the dryer for drying treatment. The drying temperature of the dryer is 80℃ and the drying time is 15 min. The moisture content of the aluminum after drying does not exceed 2%. After drying, it is packaged.

[0028] Example 2 A method for separating materials in food packaging composite products, comprising the following specific steps: (1) Raw material conveying and cleaning: The paper, aluminum film and plastic film composite dairy product packaging box is used as raw material and conveyed to the cleaning machine for cleaning treatment; the cleaning temperature of the cleaning machine is 40℃ and the cleaning time is 15min. Neutral cleaning agent is added during the cleaning process to remove residual dairy products and impurities on the surface of the raw material; after cleaning, the raw material is conveyed to the kneading machine.

[0029] (2) Initial kneading and separation: The cleaned raw materials are kneaded by a kneading machine at a speed of 200 r / min and a kneading time of 12 min to ensure that the raw materials are fully separated into pulp and aluminum-plastic mixture, and that the pulp has no obvious large solid impurities.

[0030] (3) Pulp purification and recycling: The pulp obtained in step (2) is transported to a press with a pressing pressure of 0.45 MPa and a screening aperture of 65 mesh. Through the pressing and screening process, the pulp is separated into pure pulp with a purity of not less than 98% and a trace aluminum-plastic mixture. The pure pulp is transported to a filter press for filtration. After filtration, it is packaged. The trace aluminum-plastic mixture is recycled back into the aluminum-plastic mixture separated by the kneading machine in step (2) for recycling.

[0031] (4) Aluminum-plastic purification and recycling: The aluminum-plastic mixture obtained in step (2) is sent to a cleaning machine for secondary cleaning. The cleaning time for the secondary cleaning is 8 minutes and the cleaning temperature is 30°C. The aluminum-plastic mixture is separated into a pure aluminum-plastic mixture with a pulp content of no more than 0.5% and a trace amount of pulp through cleaning. The pure aluminum-plastic mixture is sent to a reaction chamber. The trace amount of pulp is recycled back to the pulp separated by the kneading machine in step (2) for recycling.

[0032] (5) Semi-separation treatment of aluminum and plastic: Add a separating agent to the reaction chamber. The separating agent includes the following components by mass percentage: citric acid: 4.5wt%, oxalic acid: 1.0wt%, fatty alcohol polyoxyethylene ether (AEO-9): 0.2wt%, and the balance is water. The amount of separating agent added is 7.5% of the mass of the pure aluminum-plastic mixture. The treatment temperature in the reaction chamber is 50℃ and the treatment time is 25min, so that the aluminum-plastic mixture forms a uniform wrinkled semi-separation state. After the treatment is completed, it is transported to the extruder.

[0033] (6) Recycling of reagents and preparation for secondary kneading: The aluminum-plastic mixture in a semi-separated state is squeezed dry by a squeeze dryer with a squeezing pressure of 0.3 MPa. The moisture content of the aluminum-plastic mixture after squeezing does not exceed 15%. The reagent squeezed out during the squeezing process is filtered and recycled back to the reaction chamber in step (5) for reuse. After squeezing, the aluminum-plastic mixture is transported to kneading machine B.

[0034] (7) Final separation and treatment of aluminum and plastic: The aluminum-plastic mixture after extrusion is kneaded by kneading machine B. The kneading speed of kneading machine B is 250 r / min and the kneading time is 15 min, which separates it into plastic and aluminum. The plastic is sent to rinsing machine A for rinsing treatment. The rinsing time is 6.5 min. After rinsing, it is sent to granulation device. The aluminum is sent to rinsing machine B for rinsing treatment. The rinsing time is 6.5 min. After rinsing, it is sent to dryer for drying treatment. The drying temperature of dryer is 90℃ and the drying time is 20 min. The moisture content of aluminum after drying does not exceed 2%. After drying, it is packaged.

[0035] Example 3 A method for separating materials in food packaging composite products, comprising the following specific steps: (1) Raw material conveying and cleaning: The paper, aluminum film and plastic film composite dairy product packaging boxes are used as raw materials and conveyed to the cleaning machine for cleaning. The cleaning temperature of the cleaning machine is 50℃ and the cleaning time is 20min. Neutral cleaning agent is added during the cleaning process to remove residual dairy products and impurities on the surface of the raw materials. After cleaning, the raw materials are conveyed to the kneading machine.

[0036] (2) Initial kneading and separation: The cleaned raw materials are kneaded by a kneading machine at a speed of 250 r / min and a kneading time of 15 min to ensure that the raw materials are fully separated into pulp and aluminum-plastic mixture, and that the pulp has no obvious large solid impurities.

[0037] (3) Pulp purification and recycling: The pulp obtained in step (2) is transported to a press with a pressing pressure of 0.6 MPa and a screening aperture of 80 mesh. Through the pressing and screening process, the pulp is separated into pure pulp with a purity of not less than 98% and a trace aluminum-plastic mixture. The pure pulp is transported to a filter press for filtration. After filtration, it is packaged. The trace aluminum-plastic mixture is recycled back into the aluminum-plastic mixture separated by the kneading machine in step (2) for recycling.

[0038] (4) Aluminum-plastic purification and recycling: The aluminum-plastic mixture obtained in step (2) is sent to a cleaning machine for secondary cleaning. The cleaning time for the secondary cleaning is 10 minutes and the cleaning temperature is 35°C. The aluminum-plastic mixture is separated into a pure aluminum-plastic mixture with a pulp content of no more than 0.5% and a trace amount of pulp through cleaning. The pure aluminum-plastic mixture is sent to a reaction chamber. The trace amount of pulp is recycled back to the pulp separated by the kneading machine in step (2) for recycling.

[0039] (5) Semi-separation treatment of aluminum and plastic: Add a separating agent to the reaction chamber. The separating agent includes the following components by mass percentage: citric acid: 6.0 wt%, oxalic acid: 1.5 wt%, fatty alcohol polyoxyethylene ether (AEO-9): 0.3 wt%, and the balance is water. The amount of separating agent added is 10% of the mass of the pure aluminum-plastic mixture. The treatment temperature in the reaction chamber is 60°C and the treatment time is 30 min, so that the aluminum-plastic mixture forms a uniform wrinkled semi-separation state. After the treatment is completed, it is transported to the extruder.

[0040] (6) Recycling of reagents and preparation for secondary kneading: The aluminum-plastic mixture in a semi-separated state is squeezed dry by a squeeze dryer with a squeezing pressure of 0.4 MPa. The moisture content of the aluminum-plastic mixture after squeezing does not exceed 15%. The reagent squeezed out during the squeezing process is filtered and recycled back to the reaction chamber in step (5) for reuse. After squeezing, the aluminum-plastic mixture is transported to kneading machine B.

[0041] (7) Final separation and treatment of aluminum and plastic: The aluminum-plastic mixture after extrusion is kneaded by kneading machine B. The kneading speed of kneading machine B is 300 r / min and the kneading time is 20 min, which separates it into plastic and aluminum. The plastic is sent to rinsing machine A for rinsing treatment. The rinsing time is 8 min. After rinsing, it is sent to granulation device. The aluminum is sent to rinsing machine B for rinsing treatment. The rinsing time is 8 min. After rinsing, it is sent to dryer for drying treatment. The drying temperature of dryer is 100℃ and the drying time is 25 min. The moisture content of aluminum after drying does not exceed 2%. After drying, it is packaged.

[0042] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A method for separating materials in food packaging composite products, characterized in that, Includes the following steps: (1) Raw material conveying and cleaning: The raw materials of food packaging composite products are conveyed to the cleaning machine for cleaning. After cleaning, the raw materials are conveyed to the kneading machine. (2) Initial kneading and separation: The washed raw materials are kneaded by a kneading machine to separate the raw materials into pulp and aluminum-plastic mixture; (3) Pulp purification and recycling: The pulp obtained in step (2) is sent to a press and screened by the press to separate the pulp into pure pulp and trace aluminum-plastic mixture; the pure pulp is sent to a filter press for filter treatment, and after filter treatment, it is packaged; the trace aluminum-plastic mixture is recycled back into the aluminum-plastic mixture separated by the rubbing machine in step (2) for recycling. (4) Aluminum-plastic purification and recycling: The aluminum-plastic mixture obtained in step (2) is sent to a cleaning machine for secondary cleaning. The aluminum-plastic mixture is separated into pure aluminum-plastic mixture and trace pulp through cleaning. The pure aluminum-plastic mixture is sent to a reaction chamber. The trace pulp is recycled back to the pulp separated by the kneading machine in step (2) for recycling. (5) Semi-separation treatment of aluminum and plastic: Add a separating agent to the reaction chamber to treat the pure aluminum and plastic mixture, so that the aluminum and plastic mixture forms a semi-separated pleated state. After the treatment is completed, it is transported to the extruder. (6) Recycling of reagents and preparation for secondary kneading: The aluminum-plastic mixture in a semi-separated state is squeezed dry by a squeeze dryer, and the reagent squeezed out during the squeezing process is recycled to the reaction chamber in step (5) for reuse; after squeezing dry, the aluminum-plastic mixture is transported to kneading machine B; (7) Final separation and treatment of aluminum and plastic: The aluminum-plastic mixture after squeezing is kneaded by kneading machine B to separate it into plastic and aluminum; the plastic is sent to rinsing machine A for rinsing, and after rinsing, it is sent to granulation device; the aluminum is sent to rinsing machine B for rinsing, and after rinsing, it is sent to dryer for drying, and after drying, it is packaged.

2. The method for separating materials in food packaging composite products as described in claim 1, characterized in that, In step (1), the raw material for the food packaging composite product is a dairy product packaging box made of paper, aluminum film and plastic film.

3. The method for separating materials in food packaging composite products as described in claim 1, characterized in that, In step (1), the cleaning temperature of the cleaning machine is 30~50℃, the cleaning time is 10~20min, and a neutral cleaning agent is added during the cleaning process to remove residual dairy products and impurities from the surface of the raw materials.

4. The method for separating materials in a food packaging composite product as described in claim 1, characterized in that, In step (2), the kneading speed of the kneading machine is 150~250r / min and the kneading time is 8~15min, to ensure that the raw materials are fully separated into pulp and aluminum-plastic mixture, and that the pulp has no obvious large solid impurities.

5. The method for separating materials in food packaging composite products as described in claim 1, characterized in that, In step (3), the extrusion pressure of the press is 0.3~0.6MPa and the screening aperture is 50~80 mesh. The pure pulp and trace aluminum-plastic mixture are completely separated by extrusion screening. The purity of the pure pulp is not less than 98%.

6. The method for separating materials in a food packaging composite product as described in claim 1, characterized in that, In step (4), the cleaning time for the second cleaning is 5-10 minutes, the cleaning temperature is 25-35°C, and the pulp content in the pure aluminum-plastic mixture after cleaning does not exceed 0.5%.

7. The method for separating materials in food packaging composite products as described in claim 1, characterized in that, In step (5), the separating agent comprises the following components by mass percentage: citric acid: 3.0wt%~6.0wt%, oxalic acid: 0.5wt%~1.5wt%, fatty alcohol polyoxyethylene ether (AEO-9): 0.1wt%~0.3wt%, with the balance being water.

8. The method for separating materials in a food packaging composite product as described in claim 1, characterized in that, In step (5), the amount of separating agent added is 5% to 10% of the mass of the pure aluminum-plastic mixture, the processing temperature in the reaction chamber is 40 to 60°C, and the processing time is 20 to 30 minutes, to ensure that the aluminum-plastic mixture forms a uniform wrinkled semi-separated state.

9. The method for separating materials in a food packaging composite product as described in claim 1, characterized in that, In step (6), the squeezing pressure of the squeezing machine is 0.2~0.4MPa, the moisture content of the aluminum-plastic mixture after squeezing is no more than 15%, and the recovered reagent is filtered and then transported to the reaction chamber for recycling.

10. The method for separating materials in a food packaging composite product as described in claim 1, characterized in that, In step (7), the kneading speed of kneading machine B is 200~300r / min, and the kneading time is 10~20min; the rinsing time of rinsing machine A and rinsing machine B is 5~8min, and there are no residual agents or impurities on the surface of plastic and aluminum after rinsing; the drying temperature of the dryer is 80~100℃, the drying time is 15~25min, and the moisture content of aluminum after drying does not exceed 2%.