Prefabricated vegetable packaging box easy to circulate and recycle

Abstract

The invention discloses a prefabricated vegetable packaging box easy to circulate and recycle, and belongs to the technical field of catering packaging boxes, the packaging box is made of sheets made of composite materials, the sheets sequentially comprise a PETG lower surface layer, a PETG / PET bonding layer and a PET surface layer from bottom to top, and the sheets are made of PETG materials and PET materials through a multi-layer co-extrusion technology. The PETG and PET multi-layer co-extrusion product has excellent barrier property, can effectively prevent the permeation of substances such as oxygen, moisture and grease, and protects the quality and safety of contents. PETG and PET materials have the characteristics of no toxicity, no odor and no pollution, and can be recycled.

Description

Technical Field

[0001] The invention belongs to the technical field of catering packaging boxes, and relates to an easily circulated and recyclable pre-prepared food packaging box. Background Art

[0002] With the acceleration of the pace of life and the change of consumption concepts, pre-prepared meals have gradually become a new choice on people's tables. Pre-prepared meals refer to finished or semi-finished dishes that have been pre-processed by washing, cutting, matching, and processing, and preserved by freezing or vacuum packaging. Consumers only need to simply heat or cook them after purchasing them.

[0003] In the development of pre-prepared meals, packaging boxes play a vital role. However, there are many problems with traditional pre-prepared meal packaging boxes. First, most pre-prepared meal packaging boxes currently use disposable plastic materials. Although this material is low-cost and easy to use, it is difficult to recycle and reuse. A large number of disposable plastic packaging boxes are discarded at will, which has brought a heavy burden to the environment and caused serious environmental pollution.

[0004] Secondly, the traditional pre-prepared food packaging box has a complex structure. The complex structural design may be to meet the packaging needs of different dishes or to increase the aesthetics of the packaging, but it brings great difficulties to recycling and recycling. During the recycling process, the complex structure is difficult to disassemble and sort, which reduces the recycling efficiency and reusability.

[0005] Furthermore, the special nature of pre-prepared meals requires that the packaging box has good sealing and preservation properties. During transportation and storage, pre-prepared meals need to be protected from the intrusion of outside air, moisture and bacteria to ensure the safety and taste of the food. If the sealing and preservation properties of the packaging box are not good, the food may deteriorate, the taste may deteriorate, and even pose a threat to the health of consumers.

[0006] In addition, when designing pre-prepared food packaging, production costs and consumer purchase costs also need to be considered. On the one hand, manufacturers hope to reduce the cost of packaging to improve product competitiveness and profit margins. On the other hand, consumers also hope to buy reasonably priced pre-prepared food products. Therefore, how to reduce production costs and consumer purchase costs while ensuring the quality of packaging is an urgent problem to be solved. Summary of the invention

[0007] The object of the present invention is to provide a pre-prepared meal packaging box that is easily recyclable and recyclable, and to solve at least one problem in the background technology by improving the packaging box material.

[0008] The objective of the present invention is achieved through the following technical solutions: A pre-prepared food packaging box that is easy to recycle and recycle, the packaging box is made of a composite material sheet, the sheet comprises a PETG lower surface layer, a PETG / PET bonding layer and a PET surface layer from bottom to top, and the sheet is made of PETG material and PET material through a multi-layer co-extrusion technology; the preparation process of the packaging box is as follows: Step 1: Raw material preparation: drying the PETG material and the PET material to remove moisture; Step 2, mixing the PETG material and the PET material in proportion to form a co-extrusion material; Step 3, placing the co-extrusion material in a twin-screw extruder for mixing and melting, and the co-extrusion die head prepares a sheet material by multi-layer co-extrusion; Step 4: The cooling and shaping equipment rolls the sheet material extruded by the twin-screw extruder to cool it, and then the sheet material after the roll is rolled and cut by the winding and cutting equipment to form a sheet; Step 5: Send the sheet into a thermoforming machine to heat until softened, and then place it into a mold for vacuum forming.

[0009] As a further improvement of one embodiment of the present invention, the mixing ratio of the PETG material and the PET material in step 2 is 2:8 or 3:7 or 4:6.

[0010] As a further improvement of one embodiment of the present invention, the drying process of the PETG material in step 1 needs to be dried at 65-70° C. for 4-6 hours.

[0011] As a further improvement of one embodiment of the present invention, the drying process of the PET material in step 1 needs to be dried at 150-160° C. for 4-6 hours.

[0012] As a further improvement of one embodiment of the present invention, in step 3, the temperature of the feeding zone of the twin-screw extruder is set to 200-220°C, the temperature of the compression zone is set to 240-260°C, the temperature of the metering zone is set to 260-270°C, and the temperature of the die zone is set to 270-280°C. The screw speed of the twin-screw extruder is 40-60 RPM / min, and the pressure of the melt in the twin-screw extruder is 30-50 MPa.

[0013] As a further improvement of an embodiment of the present invention, in step 4, the pressure roller is cooled by water cooling or air cooling.

[0014] As a further improvement of one embodiment of the present invention, the pressure roller includes an upper roller, a middle roller and a lower roller, the temperature of the upper roller is 45°C, the temperature of the middle roller is 35°C, and the temperature of the lower roller is 35°C.

[0015] As a further improvement of one embodiment of the present invention, when the thickness of the sheet is 1 mm, the extrusion thickness of the co-extrusion die is 1.2 mm, and the pulling speed of the winding device on the cooling and shaping equipment is 3-5 m / min.

[0016] As a further improvement of one embodiment of the present invention, in step 5, the heating temperature of the thermoforming machine for the PETG lower surface layer of the sheet is 140-160°C, and the heating temperature of the thermoforming machine for the PET surface layer of the sheet is 120-140°C.

[0017] As a further improvement of one embodiment of the present invention, the softened sheet is placed in a mold, and the pressure of the vacuum forming is 4-6 bar according to the mold design and material thickness. The formed packaging box is cooled and shaped in the mold, and the cooled packaging box is demolded from the mold.

[0018] The above technical solution has the following beneficial effects: PETG has good toughness, impact strength and transparency, while PET has excellent mechanical properties, stiffness and thermal stability. Multi-layer co-extrusion technology organically combines these two materials, so that the packaging material has better physical properties and can meet various packaging needs. PETG and PET multi-layer co-extrusion products have excellent barrier properties, which can effectively prevent the penetration of substances such as oxygen, moisture, and grease, and protect the quality and safety of the contents. Both PETG and PET materials are non-toxic, odorless, and pollution-free, and can be recycled. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0020] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0021] Figure 1 This is a schematic diagram of the composite material structure provided by the present invention.

[0022] Figure 2This is a schematic diagram of a method for preparing a packaging box provided by the present invention.

[0023] In the figure: 1-PET surface layer; 2-PETG / PET bonding layer; 3-PETG lower surface layer. DETAILED DESCRIPTION

[0024] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0025] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0026] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention. Example

[0027] See also Figure 1-2 As shown, a pre-prepared meal packaging box that is easy to recycle and recycle is made of a composite sheet material, and the sheet material is composed of a PETG lower surface layer 3, a PETG / PET adhesive layer 2 and a PET surface layer 1 from bottom to top. The sheet material is made of PETG material and PET material through a multi-layer co-extrusion technology; the preparation process of the packaging box is as follows: Step 1: Prepare the raw materials, dry the PETG material (granules) and the PET material (granules) to remove moisture; the drying of the PETG material needs to be dried at 65-70°C for 4-6 hours to ensure that the PETG granules are dry; the drying of the PET material needs to be dried at 150-160°C for 4-6 hours to ensure that the PET granules are dry; Step 2, mixing the PETG material and the PET material in proportion to form a co-extrusion material; Step 3, placing the co-extruded material in a twin-screw extruder for mixing and melting, and the co-extrusion die head prepares a sheet material through a multi-layer co-extrusion method; the sheet material prepared by the multi-layer co-extrusion method has a surface layer made of PET material, an outer layer made of PETG material, and an intermediate layer made of PETG and PET blended material as a bonding layer (PETG / PET bonding layer), which plays a bonding role and strengthens the bonding between the surface layer and the outer layer; Step 4: The cooling and shaping equipment rolls the sheet material extruded by the twin-screw extruder to cool it, and then the sheet material after the roll is rolled and cut by the winding and cutting equipment to form a sheet; Step 5: Send the sheet into a thermoforming machine to heat until softened, and then place it into a mold for vacuum forming.

[0028] In this embodiment, PETG (polyethylene terephthalate) and PET (polyethylene terephthalate) are two widely used environmentally friendly materials, both of which show good environmental performance. PETG does not produce unpleasant odors during thermal processing, does not release toxic gases during incineration, and does not pollute groundwater sources after landfill treatment. These characteristics make PETG relatively environmentally friendly during the production process. At the same time, both PETG and PET can be recycled and reused, reducing the generation of waste and the impact on the environment.

[0029] In this embodiment, the PETG material selected is Skygreen® SKYG485**, which is suitable for electronic, medical and food packaging, and has good processing performance and transparency. The PET material selected is Alpek Polyester FEPET® F70, which is suitable for food packaging, fibers and films, and has good mechanical properties and transparency.

[0030] The extruder adopts 1.2 Reifenhäuser Evolution Extruder ("Reifenhäuser Evolution Series Extruder") Features: It adopts advanced screw design and temperature control system, which is suitable for efficient and high-quality sheet co-extrusion production. Advantages: Modular design, which can be flexibly adjusted according to production needs, and is suitable for the co-extrusion of various high-performance materials.

[0031] Coextrusion die head Cloeren NanoLayer™ Feedblock (Cloeren's nano-layer flow channel distributor) Features: Patented micro-layer technology can accurately control the thickness and distribution of each layer, suitable for high-quality co-extruded sheet production. Advantages: Provides high-precision and flexible co-extrusion solutions, suitable for complex multi-layer sheets.

[0032] Cooling and shaping equipment Bosch Sprang Features: Efficient cooling roller system ensures uniform cooling and shaping of the sheet, avoiding internal stress and warping. Advantages: Provides stable cooling effect and good surface quality, adapts to the production of sheets of different thicknesses and widths.

[0033] Winding and Cutting EquipmentParkinson Technologies Features: High-precision winding and cutting equipment to ensure the neatness and consistency of sheets. Advantages: Provides flexible configuration and efficient operation, suitable for a variety of sheet processing needs.

[0034] In this embodiment, for the production of easily recyclable and recyclable pre-prepared meal packaging boxes, the mixing ratio of PETG material and PET material has been carefully considered. When the mixing ratio is 2:8, on the basis of ensuring the overall performance, the characteristics of PETG material, such as good toughness, etc., are appropriately exerted, while the PET material with a relatively large proportion is used to ensure the strength and stability of the packaging box. If the mixing ratio is 3:7, the advantages of the two materials can be adjusted to a certain extent, so that the performance of the packaging box in different aspects is more balanced. When the ratio is 4:6, it can bring a new combination of performance characteristics to the product to meet the packaging needs of different pre-prepared dishes.

[0035] Although PETG and PET have similar structures, there are still certain chemical differences. Different mixing ratios may change the compatibility between the two materials, thereby affecting the bond strength. The mixing ratio affects the interface characteristics between the two materials in the coextruded material. If a certain ratio can provide better interfacial bonding, the bond strength may be improved. The crystallization behavior of PET and PETG may be different. Changes in the mixing ratio may affect the crystallinity and crystal structure of the coextruded material, which in turn affects the bond strength. Different mixing ratios may lead to changes in processing properties, such as melt viscosity, fluidity, and thermal stability, which may indirectly affect the bond strength. Changes in the mixing ratio will directly affect the physical properties of the coextruded material, such as hardness and toughness, which will also affect the bond strength.

[0036] The mixing ratio of the PETG material and the PET material used in this embodiment is 2:8 or 3:7 or 4:6, and the prepared pre-prepared meal packaging box has better quality.

[0037] In this embodiment, the parameter setting of the twin-screw extruder in step 3 is crucial. The temperature of the feed zone is set to 200-220°C. This temperature range ensures that the PETG material and the PET material can be initially softened when entering the extruder, and is ready for subsequent processing. The temperature of the compression zone is raised to 240-260°C, where the materials are further compressed and fused, and the high temperature promotes a more uniform mixing of the materials. The temperature of the metering zone is 260-270°C, which accurately controls the flow rate and extrusion speed of the material. The temperature of the die zone reaches 270-280°C, so that the material is extruded from the die in the best state to form a high-quality sheet material. At the same time, the screw speed of the twin-screw extruder is set to 40-60RPM / min, which not only ensures the full stirring and mixing of the material, but also does not cause excessive shearing of the material due to excessive speed. In addition, the pressure of the melt in the extruder is controlled at 30-50MPa, depending on the material and equipment. Appropriate pressure ensures the density and uniformity of the sheet, laying the foundation for subsequent processes such as cooling, shaping and thermoforming.

[0038] In this embodiment, there are two options for the cooling method of the pressure roller in step 4, namely water cooling and air cooling. These two cooling methods can effectively cool the sheet material extruded by the twin-screw extruder to quickly shape it. The pressure roller consists of an upper roller, a middle roller and a lower roller, and the temperature of each roller is precisely controlled. The temperature of the upper roller is set to 45°C. This temperature can ensure that the sheet material is initially cooled and shaped while avoiding problems such as brittle cracking of the sheet due to excessively low temperature. The temperatures of the middle roller and the lower roller are both 35°C. Such a temperature setting helps to further stabilize the shape of the sheet and make it smoother and more uniform. By precisely controlling the temperature of the pressure roller, it can be ensured that the sheet material maintains good quality and performance during the cooling process. At the same time, the rollers of different temperatures cooperate with each other, which can effectively improve the cooling efficiency and provide high-quality sheets for subsequent winding and cutting processes, thereby ensuring that the final pre-prepared food packaging box has good quality and stability.

[0039] In this embodiment, the required thickness of the sheet is 1mm as an example. The co-extrusion die extrusion thickness is 1.2mm, so there is a certain adjustment space in the subsequent cooling and shaping process. The traction speed of the winding device on the cooling and shaping equipment is controlled at 3-5m / min. The setting of the traction speed is crucial and must match the extrusion speed. If the traction speed is too fast, the sheet will be stretched, affecting its performance and quality; if the traction speed is too slow, the sheet will be relaxed, which is also not conducive to subsequent processing. Therefore, the winding device needs to operate smoothly to ensure that the sheet does not produce wrinkles or damage during the winding process. In order to accurately control the thickness of the sheet, it can be achieved by adjusting the extrusion amount and the spacing between the cooling rollers. When sheets of different thicknesses are required, the extrusion amount and the distance between the cooling rollers are reasonably adjusted to achieve the required thickness requirements. At the same time, the width accuracy of the sheet is ensured by the width control system to ensure that the size of the sheet meets the production standards of the pre-prepared food packaging box, providing a high-quality sheet foundation for subsequent processes such as thermoforming.

[0040] The tensile test and impact strength test of the sheet prepared above are as follows:

[0041] It can be seen that the impact resistance and elongation at break of the sheet obtained by the preparation method of the present invention are significantly better than those of conventional PET materials at room temperature.

[0042] In this embodiment, the thermoforming process in step 5 is very important for preparing high-quality pre-prepared meal packaging boxes. The thermoforming machine sets different heating temperatures for different levels of the sheet. For the PETG lower surface layer, the heating temperature is 140-160°C. Within this temperature range, the PETG material can fully soften, providing good conditions for subsequent blister molding. At the same time, higher temperatures also help to maintain the toughness and plasticity of the material. For the PET surface layer, the heating temperature is 120-140°C. Relatively low temperatures can prevent the PET material from being overly softened and affecting its strength and stability.

[0043] Next, the softened sheet is placed in the mold for blister molding. Depending on the mold design and material thickness, the pressure for blister molding is set at 4-6 bar. This pressure range ensures that the sheet fits tightly into the mold, forming a clear shape and good dimensional accuracy. The molding time is generally 3 seconds, but the specific time will depend on the material and product complexity. If the material is thicker or the product structure is more complex, the molding time may need to be appropriately extended to ensure that the sheet is fully formed.

[0044] The formed packaging box is cooled and shaped in the mold. The cooling method can be air cooling or water cooling, the purpose is to keep the mold temperature stable, so that the packaging box can solidify quickly and maintain its shape. During the cooling process, it is necessary to control the cooling speed to avoid deformation, cracking and other problems of the packaging box due to cooling too fast or too slow.

[0045] When the cooled packaging box is demolded from the mold, special care must be taken to avoid deformation caused by improper operation. The edges of the demolded packaging box need to be trimmed to remove excess scraps to make the packaging box more beautiful and neat. At the same time, quality inspection is also required to check whether the size, shape, and sealing of the packaging box meet the requirements. Qualified packaging boxes are packaged for storage and transportation.

[0046] The multilayer co-extrusion technology scheme of PETG and PET adopted by the present invention has the following advantages: PETG has good toughness, impact strength and transparency, and PET has excellent mechanical property, rigidity and thermal stability. The multilayer co-extrusion technology organically combines these two materials so that the packaging material has better physical properties and can meet various packaging requirements. PETG and PET multilayer co-extrusion products have excellent barrier properties, can effectively prevent the penetration of materials such as oxygen, moisture, grease, and protect the quality and safety of content. PETG and PET materials are both nontoxic, tasteless, pollution-free and recyclable.

[0047] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0048] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0049] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An easily recyclable and recyclable pre-prepared food packaging box, characterized by: The packaging box is made of a composite sheet, which comprises a PETG lower surface layer, a PETG / PET bonding layer and a PET surface layer from bottom to top, and the sheet is made of PETG material and PET material through a multi-layer co-extrusion technology; the preparation process of the packaging box is as follows: Step 1: Raw material preparation: drying the PETG material and the PET material to remove moisture; Step 2, mixing the PETG material and the PET material in proportion to form a co-extrusion material; Step 3, placing the co-extrusion material in a twin-screw extruder for mixing and melting, and the co-extrusion die head prepares a sheet material by multi-layer co-extrusion; Step 4: The cooling and shaping equipment rolls the sheet material extruded by the twin-screw extruder to cool it, and then the sheet material after the roll is rolled and cut by the winding and cutting equipment to form a sheet; Step 5: Send the sheet into a thermoforming machine to heat until softened, and then place it into a mold for vacuum forming.

2. The easily recyclable and recyclable prepared meal packaging box according to claim 1 is characterized by: The mixing ratio of the PETG material and the PET material in step 2 is 2:8 or 3:7 or 4:

6.

3. The easily recyclable and recyclable prepared meal packaging box according to claim 1 is characterized by: The drying process of the PETG material in step 1 needs to be dried at 65-70°C for 4-6 hours.

4. The easily recyclable and recyclable prepared meal packaging box according to claim 1, characterized in that: The drying process of the PET material in step 1 requires drying at 150-160°C for 4-6 hours.

5. The easily recyclable and recyclable prepared meal packaging box according to claim 1 is characterized by: In step 3, the temperature of the feeding zone of the twin-screw extruder is set to 200-220°C, the temperature of the compression zone is set to 240-260°C, the temperature of the metering zone is set to 260-270°C, and the temperature of the die zone is set to 270-280°C. The screw speed of the twin-screw extruder is 40-60RPM / min, and the pressure of the melt in the twin-screw extruder is 30-50 MPa.

6. The easily recyclable and recyclable prepared meal packaging box according to claim 1 is characterized by: In step 4, the pressure roller is cooled by water or air.

7. The easily recyclable and recyclable prepared meal packaging box according to claim 6, characterized in that: The pressing rollers include an upper roller, a middle roller and a lower roller. The temperature of the upper roller is 45°C, the temperature of the middle roller is 35°C, and the temperature of the lower roller is 35°C.

8. The easily recyclable and recyclable prepared meal packaging box according to claim 7, characterized in that: When the thickness of the sheet is 1 mm, the extrusion thickness of the co-extrusion die is 1.2 mm, and the pulling speed of the winding device on the cooling and shaping equipment is 3-5 m / min.

9. The easily recyclable and recyclable prepared meal packaging box according to claim 1, characterized in that: In step 5, the heating temperature of the thermoforming machine for the PETG lower surface layer of the sheet is 140-160°C, and the heating temperature of the thermoforming machine for the PET surface layer of the sheet is 120-140°C.

10. The easily recyclable and recyclable prepared meal packaging box according to claim 9, characterized in that: The softened sheet is placed in a mold. The pressure of the blister molding is 4-6 bar according to the mold design and material thickness. The molded packaging box is cooled and shaped in the mold, and the cooled packaging box is demolded from the mold.

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