Preparation method for heating PETG (Polyethylene Terephthalate Glycol) plastic uptake sheet and bonding with paperboard

Abstract

The invention relates to the technical field of packaging materials, and discloses a PETG plastic uptake sheet heating and paperboard bonding preparation method which at least comprises the following steps: S1, material preparation; s2, preparing equipment; s3, soaking and extracting; s4, the PETG plastic uptake sheet is heated; s5, positioning is carried out; s6, bonding and cooling; and S7, quality detection and arrangement. Through the steps of soaking and extracting, the oxidation resistance and flexibility of the sheet are remarkably improved, the service life of a product is effectively prolonged, the breakage rate caused by oxidation and insufficient flexibility is reduced, process parameters are accurately controlled, firm bonding between the PETG plastic uptake sheet and the paperboard is ensured, and the bonding strength is stable; the problems of layering, falling and the like of the product in the transportation and use processes are reduced, additives and solvents meeting the environmental protection standard are selected, the pollution to the environment is reduced, the heating and cooling processes are optimized, the energy consumption is reduced, the targets of energy conservation and emission reduction are achieved, and the requirement of sustainable development is met.

Description

Technical Field

[0001] The present invention relates to the technical field of packaging materials, and particularly relates to a method for heating a PETG blister sheet and bonding it to cardboard. Background Art

[0002] In modern packaging industry, the composite packaging of PETG blister sheets and cardboard has been widely used due to its unique advantages. PETG blister sheets have excellent transparency, which can clearly display the appearance of products and attract consumers' attention. Their good toughness makes the packaging not easily break when subjected to external impacts, effectively protecting the products. Cardboard provides a certain stiffness for the packaging, ensuring the stability of the packaging structure and facilitating the display and transportation of products. This combined packaging is widely used in many fields such as food, medicine, and electronic products, such as the blister packaging of food and the blister tray packaging of electronic products.

[0003] However, in the existing technology for bonding and preparing PETG blister sheets and cardboard, in terms of material properties, PETG blister sheets are prone to oxidative degradation in a conventional environment, resulting in a deterioration of transparency and physical properties, and it is difficult to improve flexibility, affecting the packaging display and protection functions and limiting their application in complex packaging scenarios. In terms of the bonding process, the traditional heating method causes uneven heating of the sheets, unstable bonding strength, and insufficient bonding quality. In terms of production efficiency and cost, the process is complex, with high energy consumption, long cycle, and increased costs due to the use of expensive glues or additives. The present invention aims to overcome these defects and provides a method for heating a PETG blister sheet and bonding it to cardboard. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for heating a PETG blister sheet and bonding it to cardboard to solve the problems raised in the above background art.

[0005] To solve the above technical problems, the present invention is solved by the following technical solutions: A method for heating a PETG blister sheet and bonding it to cardboard, comprising the following steps:

[0006] S1. Material preparation;

[0007] S2. Equipment preparation;

[0008] S3. Immersion and extraction;

[0009] S4. Heating of the PETG blister sheet;

[0010] S5. Positioning;

[0011] S6. Bonding and cooling;

[0012] S7. Quality inspection and finishing.

[0013] Preferably, the specific method in the S1, material preparation step is as follows;

[0014] S1-1. Select a PETG blister sheet that meets food hygiene and safety standards and has good flexibility and transparency, with a sheet thickness of 0.2 - 0.8 mm, and select cardboard with a gram weight of 250 - 450 g / m 2 for the cardboard;

[0015] S1-2. Prepare an appropriate amount of antioxidant and plasticizer, and select a solvent with good solubility and volatility.

[0016] Preferably, the specific method in the S2, equipment preparation step is as follows;

[0017] Equip a heating oven or hot press with an accurate temperature control function, use a high-precision positioning fixture or mold, and adopt an air-cooling or water-cooling device.

[0018] Preferably, the specific method in the S3, soaking and extraction step is as follows;

[0019] S3-1. Mix the antioxidant, plasticizer, and solvent in a certain proportion to prepare a solution. The antioxidant accounts for 2% - 5% of the total mass of the solution, the plasticizer accounts for 5% - 10% of the total mass of the solution, and the rest is the solvent;

[0020] S3-2. Put the prepared PETG blister sheet into the prepared solution and soak it for 1 - 3 hours according to the thickness of the sheet and the concentration of the additive;

[0021] S3-3. After soaking, take out the sheet from the solution and place it in a well-ventilated environment to dry.

[0022] Preferably, the specific method in the S4, PETG blister sheet heating step is as follows;

[0023] Put the PETG blister sheet that has been soaked, extracted, and dried into a heating device for heating. The heating temperature is set between 100 - 150 °C, and the heating time is controlled within 5 - 10 minutes.

[0024] Preferably, the specific method in the S5, positioning step is as follows;

[0025] S5-1. When the PETG blister sheet is heated to an appropriate temperature, quickly take out the PETG blister sheet from the heating device;

[0026] S5-2. Place the PETG blister sheet on the positioning device, then accurately cover the cardboard on the sheet, and use a positioning fixture or mold to fix the PETG blister sheet and the cardboard. The positions of the PETG blister sheet and the cardboard are accurately aligned, and the edge deviation does not exceed ±0.5 mm.

[0027] Preferably, the specific methods in the S6, bonding and cooling steps are as follows;

[0028] S6-1. Place the positioned PETG blister sheet and cardboard into a pressing device, apply a pressure of 0.5-2 MPa for bonding, and the pressing time is 1-3 minutes;

[0029] S6-2. After bonding is completed, immediately transfer the product to a cooling device for cooling. Adjust the cooling speed and time according to the size and thickness of the product to quickly cool the product to room temperature.

[0030] Preferably, the specific methods in the S7, quality inspection and finishing steps are as follows;

[0031] S7-1. Conduct a comprehensive quality inspection on the cooled product. Detect the bonding strength through methods such as tensile test and peel test, check whether there are defects such as bubbles and wrinkles on the product surface, and measure the size of the product using measuring tools. The dimensional error is controlled within ±1 mm.

[0032] Preferably, in the S3-3 step, a special drying area can be set during the drying process, and the environmental temperature and humidity are controlled.

[0033] Preferably, in the S6-2 step, the cooling speed should not be too fast or too slow.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. Through the soaking and extraction step of the present invention, the antioxidant and plasticizer fully penetrate into the interior of the PETG blister sheet in a specific proportion, significantly improving the antioxidant performance and flexibility of the sheet, effectively extending the service life of the product, and reducing the breakage rate caused by oxidation and insufficient flexibility;

[0036] 2. Precise control of process parameters such as heating, pressing, and cooling ensures firm bonding between the PETG blister sheet and the cardboard, with stable bonding strength, meeting the requirements of various packaging application scenarios, and reducing problems such as delamination and shedding during transportation and use of the product;

[0037] 3. Optimizing the heating and cooling processes reduces energy consumption, achieves the goal of energy conservation and emission reduction, and meets the requirements of sustainable development. Specific embodiments

[0038] Unless otherwise clearly specified in the context, nouns without quantifiers and nouns modified by "the" include singular and plural referents.

[0039] As used in the specification and claims, the terms "comprising", "including", "having", "may", "containing" and variations thereof as used herein refer to open transitional phrases, terms or words that require the presence of the specified element / step and allow the presence of other elements / steps. However, such description shall also be construed to describe the composition or method as "consisting of" and "consisting essentially of" the recited elements / steps, which allows only the presence of the specified elements / steps and any inevitable impurities that may result therefrom, and excludes other elements / steps.

[0040] The numerical values in the specification and claims of this application should be understood to include the same numerical values when reduced to the same number of significant figures and numerical values that differ from the said values by less than the experimental error of the conventional measurement techniques used to determine the said values of the type described in this application.

[0041] All ranges disclosed herein include the indicated endpoints and can be combined independently (e.g., the range of "2 grams to 10 grams" includes the endpoints 2 grams and 10 grams, as well as all intermediate values).

[0042] The terms "about" and "approximate" can be used to include any numerical value that can vary without changing the basic function of that value. When used with a range, "about" and "approximate" also disclose the range defined by the absolute values of the two endpoints. For example, "about 2 to about 4" also discloses the range of "2 to 4". Generally, the terms "about" and "approximate" can refer to ±10% of the indicated number. However, for temperature, the term "about" means ±1°C.

[0043] Unless otherwise expressly specified, the percentages of the elements shall be considered as weight percentages of the said alloy.

[0044] This disclosure may relate to the temperature of certain method steps. It should be noted that these indicators generally refer to the temperature set by the heat source (such as a furnace), rather than necessarily the temperature that the heated material must reach.

[0045] A method for preparing a PETG thermoformed sheet by heating and bonding it to cardboard, comprising the following steps:

[0046] S1. Material preparation;

[0047] S1-1. Select a PETG thermoformed sheet with a thickness of 0.2 - 0.8 mm that meets food hygiene and safety standards and has good flexibility and transparency. The sheet surface should be flat and free of defects. Select cardboard with a gram weight of 250 - 450 g / m 2 according to the packaging requirements. The cardboard should have good stiffness, printability and surface flatness to ensure the subsequent printing and the bonding effect with the PETG thermoformed sheet;

[0048] S1-2. Prepare an appropriate amount of antioxidant and plasticizer, and select a solvent with good solubility and volatility. The antioxidant can prevent the PETG blister sheet from oxidative degradation during heating and use, and the plasticizer can increase the flexibility and plasticity of the sheet. The selected solvent should not damage the PETG blister sheet and will not cause swelling, deformation or performance degradation of the sheet.

[0049] S2. Equipment preparation;

[0050] Equip a heating oven or hot press with precise temperature control function to ensure that the PETG blister sheet can be heated evenly and stably, with the temperature control error within ±2°C. Use a high-precision positioning fixture or mold to ensure that the position accuracy of the PETG blister sheet and the cardboard during the bonding process is within ±0.5 mm. Adopt an air-cooling or water-cooling device that can precisely control the cooling rate according to product requirements, and the cooling rate error is controlled within ±5%.

[0051] S3. Immersion extraction;

[0052] S3-1. Mix the antioxidant, plasticizer and solvent in a certain proportion to prepare a solution. The antioxidant accounts for 2% - 5% of the total mass of the solution, the plasticizer accounts for 5% - 10% of the total mass of the solution, and the rest is the solvent;

[0053] S3-2. Put the prepared PETG blister sheet into the prepared solution and soak it for 1 - 3 hours according to the thickness of the sheet and the concentration of the additive;

[0054] S3-3. After soaking, take out the sheet from the solution and place it in a well-ventilated environment to dry. A special drying area can be set during the drying process, and the environmental temperature and humidity can be controlled to accelerate the drying speed and ensure the drying effect.

[0055] S4. Heating of PETG blister sheet;

[0056] Put the PETG blister sheet that has been soaked, extracted and dried into the heating equipment for heating. The heating temperature is set between 100 - 150°C, and the heating time is controlled within 5 - 10 minutes.

[0057] S5. Positioning;

[0058] S5-1. When the PETG blister sheet is heated to the appropriate temperature, quickly take out the PETG blister sheet from the heating equipment;

[0059] S5-2. Place the PETG blister sheet on the positioning equipment, then accurately cover the cardboard on the sheet, and use a positioning fixture or mold to fix the PETG blister sheet and the cardboard. The positions of the PETG blister sheet and the cardboard are accurately aligned, and the edge deviation does not exceed ±0.5 mm.

[0060] S6, Bonding and Cooling;

[0061] S6-1, Place the positioned PETG thermoformed sheet and cardboard into the pressing equipment, apply a pressure of 0.5-2 MPa for bonding, and the pressing time is 1-3 minutes;

[0062] S6-2, After bonding is completed, immediately transfer the product to the cooling equipment for cooling. Adjust the cooling speed and time according to the size and thickness of the product to quickly cool the product to room temperature. The cooling speed should not be too fast to avoid generating internal stress and causing product deformation; nor should it be too slow to avoid affecting production efficiency.

[0063] S7, Quality Inspection and Finishing;

[0064] S7-1, Conduct a comprehensive quality inspection on the cooled product. Detect the bonding strength through methods such as tensile test and peel test, check whether there are defects such as bubbles and wrinkles on the product surface, and measure the size of the product using measuring tools. The dimensional error is controlled within ±1 mm;

[0065] S7-2, According to the shape and size of the product, select appropriate packaging materials and packaging methods to protect and label the product. Store the packaged product in a dry and ventilated warehouse to avoid damage and contamination of the product.

[0066] Specific steps: Select a PETG thermoformed sheet that meets food hygiene and safety standards, has good flexibility and transparency, and a sheet thickness of 0.2-0.8 mm. The sheet surface should be flat and free of defects. Select a grammage of 250-450 g / m according to packaging requirements 2The cardboard should have good stiffness, printing adaptability, and surface flatness to ensure the subsequent printing and the lamination effect with the PETG thermoformed sheet. Prepare an appropriate amount of antioxidant and plasticizer, and select a solvent with good solubility and volatility. The antioxidant can prevent the PETG thermoformed sheet from oxidative degradation during heating and use, and the plasticizer can increase the flexibility and plasticity of the sheet. The selected solvent should not damage the PETG thermoformed sheet and should not cause swelling, deformation, or performance degradation of the sheet. Equip a heating oven or hot press with precise temperature control function to ensure that the PETG thermoformed sheet can be heated evenly and stably, with the temperature control error within ±2°C. Use a high-precision positioning fixture or mold to ensure that the position accuracy of the PETG thermoformed sheet and the cardboard during the bonding process is within ±0.5 mm. Adopt an air-cooling or water-cooling device that can accurately control the cooling speed according to product requirements, with the cooling speed error controlled within ±5%. Mix the antioxidant, plasticizer, and solvent in a certain proportion to prepare a solution. The antioxidant accounts for 2% - 5% of the total mass of the solution, the plasticizer accounts for 5% - 10% of the total mass of the solution, and the rest is the solvent. Place the prepared PETG thermoformed sheet into the prepared solution and soak it for 1 - 3 hours according to the thickness of the sheet and the concentration of the additives. After soaking, take out the sheet from the solution and place it in a well-ventilated environment to dry. A special drying area can be set during the drying process, and the environmental temperature and humidity can be controlled to accelerate the drying speed and ensure the drying effect. Place the PETG thermoformed sheet that has been soaked, extracted, and dried into a heating device for heating. The heating temperature is set between 100 - 150°C, and the heating time is controlled within 5 - 10 minutes. When the PETG thermoformed sheet is heated to the appropriate temperature, quickly take out the PETG thermoformed sheet from the heating device. Place the PETG thermoformed sheet on a positioning device, and then accurately cover the cardboard on the sheet. Use a positioning fixture or mold to fix the PETG thermoformed sheet and the cardboard. The positions of the PETG thermoformed sheet and the cardboard are accurately aligned, and the edge deviation does not exceed ±0.5 mm. Place the positioned PETG thermoformed sheet and cardboard into a pressing device and apply a pressure of 0.5 - 2 MPa for bonding. The pressing time is 1 - 3 minutes. After bonding, immediately transfer the product to a cooling device for cooling. Adjust the cooling speed and time according to the size and thickness of the product to quickly cool the product to room temperature. The cooling speed should not be too fast to avoid generating internal stress and causing product deformation; nor should it be too slow to avoid affecting production efficiency. Conduct a comprehensive quality inspection on the cooled product. Detect the bonding strength through methods such as tensile test and peel test, check whether there are defects such as bubbles and wrinkles on the product surface, and measure the size of the product using measuring tools. The size error is controlled within ±1 mm. Select appropriate packaging materials and packaging methods according to the shape and size of the product to protect and label the product. Store the packaged product in a dry and ventilated warehouse to avoid damage and contamination of the product.

[0067] Example 1:

[0068] S1. Material preparation;

[0069] S1-1. Select a PETG blister sheet with a thickness of 0.3 mm and a cardboard with a grammage of 300 g / m 2 ².

[0070] S1-2. Prepare a hindered phenol antioxidant, dioctyl phthalate as a plasticizer, and ethyl acetate as a solvent.

[0071] S2. Equipment preparation;

[0072] Use a heating oven with the temperature controlled within ±2°C, use a high-precision mold for positioning with an accuracy of ±0.5 mm, and cool with a water-cooling device with a controllable cooling rate.

[0073] S3. Immersion extraction;

[0074] S3-1. When preparing the solution, the antioxidant accounts for 4%, the plasticizer accounts for 6%, and the rest is the solvent;

[0075] S3-2. Put the prepared PETG blister sheet into the prepared solution and soak for 2.5 hours;

[0076] S3-3. After soaking, take out the sheet from the solution and place it in a ventilated area at a temperature of 25°C and a relative humidity of 50% to dry.

[0077] S4. Heating of the PETG blister sheet;

[0078] Put the sheet into the heating oven, set the temperature to 120°C, and heat for 7 minutes.

[0079] S5. Positioning;

[0080] S5-1. When the PETG blister sheet is heated to the appropriate temperature, quickly take out the PETG blister sheet from the heating equipment;

[0081] S5-2. Align the sheet and the cardboard precisely in the positioning fixture, with the edge deviation controlled within ±0.3 mm.

[0082] S6. Bonding and cooling;

[0083] S6-1. Put the positioned PETG blister sheet and cardboard into the pressing equipment, apply a pressure of 1 MPa for 2 minutes to bond;

[0084] S6-2. After bonding, immediately transfer the product to the cooling equipment and cool it with an air-cooling equipment at a moderate speed to quickly reduce the product to room temperature.

[0085] S7. Quality inspection and sorting;

[0086] S7-1. After inspection, the bonding strength is high, the product surface has no defects, and the dimensional error is within ±0.5 mm;

[0087] S7-2. Packed with plastic film and stored in a dry and ventilated warehouse.

[0088] Specific steps: Select a PETG blister sheet with a thickness of 0.3 mm, choose a cardboard with a grammage of 300 g / m 2 For the antioxidant, choose hindered phenols, for the plasticizer, choose dioctyl phthalate, the solvent is ethyl acetate, use a heating oven with a temperature control accuracy of up to ±1 °C, use a positioning fixture with an accuracy of ±0.3 mm, the cooling equipment uses air cooling and can precisely adjust the cooling speed. Prepare a solution according to the ratio of antioxidant accounting for 3% of the total mass of the solution, plasticizer accounting for 8%, and solvent accounting for 89%. Put the prepared PETG blister sheet into the prepared solution and soak for 2 hours. After soaking, take out the sheet from the solution and place it in a ventilated area with a temperature of 25 °C and a relative humidity of 50% to dry. Put the sheet into the heating oven, set the temperature to 120 °C and heat for 7 minutes. When the PETG blister sheet is heated to the appropriate temperature, quickly take out the PETG blister sheet from the heating equipment, accurately align the sheet and the cardboard in the positioning fixture, and control the edge deviation within ±0.3 mm. Put the positioned PETG blister sheet and cardboard into the pressing equipment and apply a pressure of 1 MPa for 2 minutes for bonding. After bonding, immediately transfer the product to the cooling equipment and cool it at a moderate speed with the air cooling equipment to quickly reduce the product to room temperature. After inspection, the bonding strength is high, the product surface has no defects, and the dimensional error is within ±0.5 mm. Packed with plastic film and stored in a dry and ventilated warehouse.

[0089] Example 2:

[0090] S1. Material preparation;

[0091] S1-1. Select a PETG blister sheet with a thickness of 0.5 mm and choose a cardboard with a grammage of 400 g / m2;

[0092] S1-2. Prepare the antioxidant as dilauryl thiodipropionate, the plasticizer as epoxidized soybean oil, and the solvent as acetone.

[0093] S2. Equipment preparation;

[0094] Use a heating oven with a temperature control accuracy of up to ±1 °C, use a positioning fixture with an accuracy of ±0.3 mm, and the cooling equipment uses air cooling and can precisely adjust the cooling speed.

[0095] S3. Soaking and extraction;

[0096] S3-1. Prepare a solution with the proportion of antioxidant accounting for 3% of the total mass of the solution, plasticizer accounting for 8%, and solvent accounting for 89%.

[0097] S3-2. Put the prepared PETG blister sheet into the prepared solution and soak for 2 hours.

[0098] S3-3. After soaking, take out the sheet from the solution and let it dry in an environment with good ventilation, a temperature of 28°C, and a humidity of 40%.

[0099] S4. Heat the PETG blister sheet.

[0100] Put the sheet into a heating oven, set the temperature at 130°C, and heat for 8 minutes.

[0101] S5. Positioning.

[0102] S5-1. When the PETG blister sheet is heated to the appropriate temperature, quickly take out the PETG blister sheet from the heating equipment.

[0103] S5-2. Use a mold to position the sheet and the cardboard, with the edge deviation within ±0.5mm.

[0104] S6. Bonding and cooling.

[0105] S6-1. Apply a pressure of 1.5 MPa in the pressing equipment and bond for 2.5 minutes.

[0106] S6-2. After bonding, immediately transfer the product to a water cooling device for rapid cooling to avoid product deformation.

[0107] S7. Quality inspection and finishing.

[0108] S7-1. After inspection, the product is firmly bonded, has no appearance defects, and the dimensional error is ±0.8mm.

[0109] S7-2. Pack the product in a cardboard box and store it in a dry and well-ventilated place.

[0110] Specific steps: Select a PETG thermoformed sheet with a thickness of 0.5 mm, choose a cardboard with a grammage of 400 g / m², prepare dilauryl thiodipropionate as the antioxidant, epoxidized soybean oil as the plasticizer, and acetone as the solvent. Use a heating oven with a temperature control accuracy of up to ±1 °C, a positioning fixture with an accuracy of ±0.3 mm, and an air-cooling device for the cooling equipment, which can precisely adjust the cooling rate. Prepare a solution according to the ratio of 3% antioxidant, 8% plasticizer, and 89% solvent in the total mass of the solution. Immerse the prepared PETG thermoformed sheet in the prepared solution for 2 hours. After the immersion is completed, take out the sheet from the solution and place it in a well-ventilated environment with a temperature of 28 °C and a humidity of 40% to dry. Put the sheet into the heating oven, set the temperature to 130 °C, and heat for 8 minutes. When the PETG thermoformed sheet is heated to the appropriate temperature, quickly take out the PETG thermoformed sheet from the heating equipment, position the sheet and the cardboard with the help of a mold, with the edge deviation within ±0.5 mm. Apply a pressure of 1.5 MPa in the pressing equipment and bond for 2.5 minutes. After the bonding is completed, immediately transfer the product to the water-cooling device for rapid cooling to avoid product deformation. After testing, the product is firmly bonded, has no appearance defects, and the dimensional error is ±0.8 mm. Pack the product in a cardboard box and store it in a dry and well-ventilated place.

[0111] Example 3:

[0112] S1. Material preparation;

[0113] S1-1. Select a PETG thermoformed sheet with a thickness of 0.4 mm and a cardboard with a grammage of 350 g / m 2 ²;

[0114] S1-2. Prepare antioxidant 1010 as the antioxidant, tributyl citrate as the plasticizer, and a mixed solvent of ethyl acetate and acetone in a 1:1 ratio as the solvent.

[0115] S2. Equipment preparation;

[0116] Use a heating oven with precise temperature control, an error of ±1.5 °C, a positioning fixture with an accuracy of ±0.4 mm, and an air-cooling device that can adjust the cooling rate.

[0117] S3. Immersion extraction;

[0118] S3-1. The antioxidant in the solution accounts for 2.5%, the plasticizer accounts for 7%, and the rest is the mixed solvent;

[0119] S3-2. Immerse the prepared PETG thermoformed sheet in the prepared solution for 1.5 hours;

[0120] S3-3. After the immersion is completed, take out the sheet from the solution and place it in a well-ventilated environment with a temperature of 26 °C and a humidity of 45% to dry.

[0121] S4. Heating of PETG thermoformed sheet;

[0122] Put the sheet into a heating oven, set the temperature of the heating oven to 125 °C, and heat for 6 minutes.

[0123] S5. Positioning;

[0124] S5-1. When the PETG thermoformed sheet is heated to the appropriate temperature, quickly take out the PETG thermoformed sheet from the heating equipment;

[0125] S5-2. Fix the sheet and the cardboard with a positioning fixture to ensure that the edge deviation does not exceed ±0.4 mm.

[0126] S6. Bonding and cooling;

[0127] S6-1. Apply a pressure of 1.2 MPa with a pressing equipment and bond for 1.5 minutes;

[0128] S6-2. After bonding is completed, immediately transfer the product to an air-cooling device for rapid cooling to avoid product deformation.

[0129] S7. Quality inspection and finishing;

[0130] S7-1. The inspection shows that the bonding strength of the product meets the standard, there are no obvious defects, and the dimensional error is ±0.6 mm;

[0131] S7-2. Pack it with a bubble bag and store it in a dry and ventilated place in the warehouse.

[0132] Specific steps: Select a PETG thermoformed sheet with a thickness of 0.4 mm and a grammage of 350 g / m 2Cardboard is prepared, with antioxidant 1010 as the antioxidant, tributyl citrate as the plasticizer, and a mixed solvent of ethyl acetate and acetone in a 1:1 ratio as the solvent. The heating oven has precise temperature control with an error of ±1.5°C. A positioning fixture with an accuracy of ±0.4 mm is used. The air-cooling equipment can adjust the cooling speed. The antioxidant accounts for 2.5% and the plasticizer accounts for 7% in the solution, and the rest is the mixed solvent. The prepared PETG thermoformed sheet is placed in the prepared solution and soaked for 1.5 hours. After soaking, the sheet is taken out of the solution and dried in an environment with good ventilation, a temperature of 26°C, and a humidity of 45%. The sheet is then placed in the heating oven, and the temperature of the heating oven is adjusted to 125°C and heated for 6 minutes. When the PETG thermoformed sheet is heated to the appropriate temperature, it is quickly taken out of the heating equipment. The sheet and the cardboard are fixed with a positioning fixture to ensure that the edge deviation does not exceed ±0.4 mm. The pressing equipment applies a pressure of 1.2 MPa and bonds for 1.5 minutes. After bonding, the product is immediately transferred to the air-cooling device for rapid cooling to avoid product deformation. The test shows that the bonding strength of the product meets the standard, there are no obvious defects, and the dimensional error is ±0.6 mm. After packaging with a bubble bag, it is stored in a dry and well-ventilated warehouse.

[0133] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method for bonding a PETG thermoformed sheet to cardboard by heating, characterized in that, It includes the following steps: S1. Material preparation; S2. Equipment preparation; S3. Immersion extraction; S4. Heating of PETG blister sheet; S5. Positioning; S6. Bonding and cooling; S7. Quality inspection and finishing.

2. A method for preparing a PETG thermoformed sheet by heating and bonding it to cardboard according to claim 1, characterized in that: The specific method in the step of S1, material preparation, is as follows; S1-1. Select a PETG blister sheet that meets food hygiene and safety standards and has good flexibility and transparency, with a sheet thickness of 0.2 - 0.8 mm, and select a cardboard with a gram weight of 250 - 450 g / m 2 according to the packaging requirements; S1-2. Prepare an appropriate amount of antioxidant and plasticizer, and select a solvent with good solubility and volatility.

3. A method for preparing a PETG thermoformed sheet by heating and bonding it to cardboard according to claim 1, characterized in that: The specific method in the step of S2, equipment preparation, is as follows; Equip a heating oven or hot press with an accurate temperature control function, use a high-precision positioning fixture or mold, and adopt an air-cooling or water-cooling device.

4. A method for preparing a PETG thermoformed sheet by heating and bonding it to cardboard according to claim 1, characterized in that: The specific method in the step of S3, immersion extraction, is as follows; S3-1. Mix the antioxidant, plasticizer and solvent in a certain proportion to prepare a solution. The antioxidant accounts for 2% - 5% of the total mass of the solution, the plasticizer accounts for 5% - 10% of the total mass of the solution, and the rest is the solvent; S3-2. Put the prepared PETG blister sheet into the prepared solution and soak it for 1 - 3 hours according to the thickness of the sheet and the concentration of the additive; S3-3. After soaking, take out the sheet from the solution and place it in a well-ventilated environment to dry.

5. A method for preparing a PETG thermoformed sheet by heating and bonding it to cardboard according to claim 1, characterized in that: The specific method in the step of S4, heating of PETG blister sheet, is as follows; Put the PETG blister sheet that has been subjected to immersion extraction and drying into a heating device for heating. The heating temperature is set between 100 - 150°C, and the heating time is controlled within 5 - 10 minutes.

6. A method for preparing a PETG thermoformed sheet by heating and bonding it to cardboard according to claim 1, characterized in that: The specific method in the step of S5, positioning, is as follows; S5-1. When the PETG blister sheet is heated to an appropriate temperature, quickly take out the PETG blister sheet from the heating device; S5-2. Place the PETG blister sheet on a positioning device, then accurately cover the cardboard on the sheet, and use a positioning fixture or mold to fix the PETG blister sheet and the cardboard. The positions of the PETG blister sheet and the cardboard are accurately aligned, and the edge deviation does not exceed ±0.5mm.

7. A method for preparing a PETG thermoformed sheet by heating and bonding it to cardboard according to claim 1, characterized in that: The specific method in the step of S6, bonding and cooling, is as follows; S6-1. Put the positioned PETG blister sheet and cardboard into a pressing device, apply a pressure of 0.5 - 2 MPa for bonding, and the pressing time is 1 - 3 minutes; S6-2. After bonding, immediately transfer the product to a cooling device for cooling. Adjust the cooling speed and time according to the size and thickness of the product to quickly cool the product to room temperature.

8. A method for preparing a PETG thermoformed sheet by heating and bonding it to cardboard according to claim 1, characterized in that: The specific method in the step of S7, quality inspection and finishing, is as follows; S7-1. Conduct a comprehensive quality inspection on the cooled product. Detect the bonding strength through methods such as tensile test and peel test, check whether there are defects such as bubbles and wrinkles on the surface of the product, and measure the size of the product using measuring tools. The dimensional error is controlled within ±1mm; S7-2. According to the shape and size of the product, select appropriate packaging materials and packaging methods to protect and label the product, and store the packaged product in a dry and ventilated warehouse.

9. A method for preparing a PETG thermoformed sheet by heating and bonding it to cardboard according to claim 4, characterized in that: In the step of S3-3, a special drying area can be set during the drying process, and the environmental temperature and humidity can be controlled.

10. A method for preparing a PETG thermoformed sheet by heating and bonding it to cardboard according to claim 7, characterized in that: In the step of S6-2, the cooling speed should not be too fast nor too slow.