A packaging film and its preparation process
By introducing a temperature-sensitive regulating layer of rare earth modified carbon nanotubes and alumina-based porous ceramic powder into the packaging film, the problem of uneven heat distribution during hot stamping is solved, achieving uniform heat transfer, avoiding blurry or distorted images, and improving the quality of hot stamping.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI LINGBO PLASTIC PACKAGING CO LTD
- Filing Date
- 2024-12-18
- Publication Date
- 2026-06-30
Smart Images
Figure BDA0005195342430000081 
Figure BDA0005195342430000091
Abstract
Description
Technical Field
[0001] This application relates to the field of packaging film technology, and more specifically, to a packaging film and its preparation process. Background Technology
[0002] Packaging film is a type of film used for packaging goods. It is usually made by extruding a mixture of polyethylene resins. It has puncture resistance, high strength and performance, is non-toxic and has excellent waterproof properties. It is widely used for the external packaging of products in industries such as foreign trade export, papermaking, hardware, plastics and chemicals, building materials, food, and pharmaceuticals.
[0003] Hot stamping packaging film, in particular, possesses not only the luster and texture of metal but also the flexibility and plasticity of plastic film. It is commonly used to create high-end packaging boxes and brochures, enhancing the product's grade and visual appeal. The principle of hot stamping is to melt the insulating layer of the electroplated aluminum by heating, causing the aluminum layer to peel off from the base film and adhere to the stamping material. After cooling and solidification, it creates a metallic luster. The preparation process for hot stamping packaging film typically includes a preparation stage and the hot stamping process. The preparation stage involves preparing the material to be stamped, i.e., the hot stamping film material, and selecting suitable electroplated aluminum, which comes in various colors, including gold, silver, copper, inner red, and inner blue. The hot stamping process involves engraving the designed graphics onto a metal plate, pressing the graphics onto the material, placing the electroplated aluminum between the hot stamping plate and the material, heating the hot stamping plate to approximately 100-150 degrees Celsius, pressing down to peel off the electroplated aluminum and transfer it onto the material, and finally lifting the hot stamping plate away from the material, removing the waste electroplated aluminum, thus completing the hot stamping process.
[0004] Regarding the aforementioned technologies, the inventors believe that, due to the complexity of the graphics and text during the hot stamping process, it is difficult for the hot stamping plate to ensure uniform heat transfer during the hot pressing process. Consequently, during the electroplated aluminum transfer process, the graphics and text are prone to appear blurry or hazy, resulting in a reduction in the overall quality of the packaging film.
[0005] Therefore, there is an urgent need to propose a solution to address the aforementioned technical problems. Summary of the Invention
[0006] In order to improve the uniform heat transfer during hot stamping, ensure the stability of the electroplated aluminum transfer process, effectively avoid the phenomenon of blurry or hazy images, and thus obtain a packaging film with excellent hot stamping quality, this application provides a packaging film and its preparation process.
[0007] In a first aspect, this application provides a packaging film, which adopts the following technical solution:
[0008] A packaging film is made by hot stamping a gold foil transfer layer, a temperature-sensitive regulating layer, an ink layer, and an LDPE film layer, which are sequentially laminated from top to bottom. The temperature-sensitive regulating layer is made from raw materials comprising the following parts by weight:
[0009] 30-45 parts of silicone-acrylic emulsion;
[0010] 1-2 parts polyethylene glycol;
[0011] 10-15 parts deionized water;
[0012] Thickener 4-6 parts;
[0013] Leveling agent 0.1-0.3 parts;
[0014] Defoamer 0.1-0.3 parts;
[0015] Rare earth modified carbon nanotubes, 3-6 parts;
[0016] 2-5 parts of alumina-based porous ceramic powder;
[0017] The rare earth modified carbon nanotubes were prepared by the following method:
[0018] S1. The carbon nanotube raw material is purified by acid and then ball-milled to obtain pretreated carbon nanotubes;
[0019] S2. Prepare a neodymium chloride solution with ethanol as solvent, adjust the pH value of the solution with nitric acid, then add the pretreated carbon nanotubes for soaking and ultrasonic treatment, and finally take them out and dry them to obtain rare earth modified carbon nanotubes.
[0020] By adopting the above technical solution, in the hot stamping process, the hot stamping plate is heated and then the hot stamping foil is heated, so that the gold powder layer of the hot stamping foil is transferred to the printing surface through the gold foil transfer layer; and by setting a temperature-sensitive regulating layer, during the process of the hot stamping plate being heated and pressed to peel off the electroplated aluminum and transfer it to the material, the temperature-sensitive regulating layer provides excellent heat conduction and heat dispersion performance, ensuring the heat uniformity of the printing surface, resulting in better electroplated aluminum transfer effect, and thus effectively avoiding the phenomenon of blurry or hazy images. Regarding the use of the temperature-sensing regulating layer, rare-earth modified carbon nanotubes and alumina-based porous ceramic powder are mainly used to achieve better thermal conductivity and thermal dispersion performance. Rare-earth modified carbon nanotubes are obtained by surface modification of carbon nanotubes with rare-earth elements. While carbon nanotubes possess excellent thermal conductivity, they suffer from problems such as easy agglomeration, poor dispersibility, and weak bonding with the matrix. Rare-earth modification not only effectively improves these issues but also utilizes the properties of neodymium to enhance thermal conductivity and thermal dispersion performance. The thermal conductivity of alumina-based porous ceramic powder is approximately 20-30 W / (m·K), which is lower than that of common metals such as aluminum and copper but higher than most non-metallic materials, exhibiting excellent performance, especially in high-temperature environments. Its excellent thermal conductivity effectively conducts heat, making it suitable for applications requiring high-temperature heat conduction. When alumina-based porous ceramic powder and rare-earth modified carbon nanotubes are used together, they exhibit excellent synergistic effects. Due to the porosity of the alumina-based porous ceramic powder, the rare-earth modified carbon nanotubes and alumina-based porous ceramic powder can form an interwoven network structure. The rare-earth elements on the surface of the rare-earth modified carbon nanotubes give this network structure excellent bonding stability and outstanding thermal conductivity and heat dissipation. This significantly improves the uniformity of heat transfer during hot stamping, effectively preventing blurry or hazy images and resulting in packaging films with superior hot stamping quality.
[0021] Preferably, the weight ratio of the rare earth modified carbon nanotubes to the alumina-based porous ceramic powder is 5:3.
[0022] By adopting the above technical solution, when rare earth modified carbon nanotubes and alumina-based porous ceramic powder of the above weight ratio are used together, a relatively uniform network structure system can be formed in the temperature-sensing regulating layer, which can bring about better heat conduction and heat dissipation effects, thereby achieving better hot stamping quality and obtaining packaging film with clear graphics and text during application.
[0023] Preferably, the concentration of the neodymium chloride solution is 2.5-4.5 mol / mL, and the mixing ratio of the pretreated carbon nanotubes and the neodymium chloride solution is (900-1200) mL:1 mg.
[0024] By adopting the above technical solution, the neodymium chloride solution of the above concentration is mixed and modified with the pretreated carbon nanotubes in the above proportion, which enables neodymium to be more uniformly combined on the surface of the carbon nanotubes, and the obtained rare earth modified carbon nanotubes can also form a more stable combination with alumina-based porous ceramic powder, thereby enabling the temperature-sensing regulating layer to exhibit better thermal conductivity and thermal dispersion in practical applications.
[0025] Preferably, the carbon nanotube raw material has a diameter of 10-30 nm and a length of 0.5-20 μm; the alumina-based porous ceramic powder has a particle size of 1-5 μm.
[0026] By adopting the above technical solution, the rare earth modified carbon nanotubes obtained after the above-mentioned carbon nanotubes are modified can form a relatively uniform and stable combination with the above-mentioned alumina-based porous ceramic powder. The network structure system formed has excellent performance in heat conduction and heat dispersion, and can thus form a temperature-sensitive regulating layer with better application quality. It has excellent effects in improving the uniform heat transfer during hot stamping, ensuring the stability during the electroplated aluminum transfer process, and effectively avoiding the phenomenon of blurry or hazy images.
[0027] Preferably, the thickener is one or a combination of several of sodium starch phosphate, sodium polyacrylate and sodium carboxymethyl cellulose.
[0028] By adopting the above technical solutions, thickeners can increase the viscosity of the mixture, adjust the rheological properties of the mixture, and improve the adhesion and durability of the mixture. All of the above types of thickeners are suitable for the preparation of temperature-sensitive regulating layers, which is conducive to forming a uniform and stable temperature-sensitive regulating layer and exerting excellent and stable corresponding effects.
[0029] Preferably, the leveling agent is one or a combination of several of polydimethylsiloxane, polyacrylic acid, and carboxymethyl cellulose.
[0030] By adopting the above technical solution, the leveling agent can reduce the surface tension of the mixture, so that a flat, smooth and uniform layer structure can be formed during the film-forming process of the raw materials required for the preparation of the temperature-sensing layer, thereby ensuring the excellent performance of the corresponding function of the temperature-sensing layer.
[0031] Preferably, the defoamer is one or a combination of several of emulsified silicone oil, polyoxypropylene glycerol ether, and stearic acid.
[0032] By adopting the above technical solution, a large amount of foam will be generated during the preparation of the raw materials required for the temperature-sensing regulating layer due to various reasons. The defoamer can effectively eliminate these foams, ensuring that the temperature-sensing regulating layer has structural integrity and density, and thus can exert excellent and stable corresponding effects.
[0033] Secondly, this application provides a method for preparing a packaging film, which adopts the following technical solution:
[0034] A method for preparing a packaging film includes the following steps:
[0035] (1) Prepare raw materials containing silicone acrylic emulsion, polyethylene glycol, deionized water, thickener, leveling agent, defoamer, rare earth modified carbon nanotubes and alumina-based porous ceramic powder according to the formula.
[0036] (2) After stirring and mixing the silicone acrylic emulsion, polyethylene glycol and deionized oil in step (1), add thickener, rare earth modified carbon nanotubes and alumina-based porous ceramic powder and continue stirring and mixing. Finally, add leveling agent and defoamer and mix evenly to obtain temperature-sensitive regulating layer material.
[0037] (3) Print an ink layer on the LDPE film layer, coat the surface of the ink layer with a temperature-sensitive regulating layer, dry and form it, and then combine it with the gold foil transfer layer to obtain a composite film. Finally, after hot stamping the composite film, a packaging film is obtained.
[0038] By adopting the above technical solution, the above preparation method is simple to operate. Rare earth modified carbon nanotubes and alumina-based porous ceramic powder can fully interact with each other. After being mixed with other raw materials and carried out subsequent operations, a temperature-sensing regulating layer with excellent performance can be formed in the packaging film structure. In this way, a high-quality packaging film can be obtained after subsequent processing, and the whole is also suitable for large-scale industrial production.
[0039] Preferably, in step (3), the coating amount of the temperature-sensing conditioning layer is 6-8 g / m². 2 After coating, the drying temperature is 80-90℃ and the drying time is 5-10 minutes.
[0040] By adopting the above technical solution, in the preparation and molding of the temperature-sensitive regulating layer, the temperature-sensitive regulating layer formed by the above-mentioned amount of coating material can meet the requirements of uniform temperature conduction and dispersion during hot stamping; and the selection and matching of the above-mentioned drying temperature and drying time can ensure that a temperature-sensitive regulating layer with a uniform and complete structure is obtained, thereby allowing the rare earth modified carbon nanotubes and alumina-based porous ceramic powder in the temperature-sensitive regulating layer to fully cooperate and exert excellent corresponding effects.
[0041] In summary, this application has the following beneficial effects:
[0042] This application sets up a temperature-sensing regulating layer and forms an interwoven network structure system with rare earth modified carbon nanotubes and alumina-based porous ceramic powder, thereby bringing excellent heat conduction and heat dispersion performance. This is beneficial to significantly improve the uniformity of heat transfer during hot stamping, and can effectively avoid the phenomenon of blurry or hazy images and text, resulting in packaging film with excellent hot stamping quality. Detailed Implementation
[0043] The present application will be further described in detail below with reference to preparation examples, embodiments and comparative examples.
[0044] Unless otherwise specified, all raw materials used in the preparation examples, embodiments, and comparative examples of this application are commercially available.
[0045] The silicone-acrylic emulsion was purchased from Anhui Zhongen Chemical Co., Ltd., model SA-108.
[0046] Polyethylene glycol was purchased from Haian Petrochemical Plant in Jiangsu Province as PEG-1000.
[0047] The carbon nanotubes were purchased from Guangzhou Hongwu Materials Technology Co., Ltd.
[0048] Alumina-based porous ceramic powder was purchased from Jiyuan Jinghua Engineering Ceramic Materials Co., Ltd.
[0049] The gold foil transfer layer consists of a PET film layer and a colored aluminum powder layer coated on the lower surface of the PET film layer. The PET film layer is SKC film TU94 with a thickness of 0.05 mm, and the colored aluminum powder layer has a thickness of 0.002 mm. The aluminum powder in the layer has a mesh size of 200.
[0050] The ink layer was formed by printing and drying using APU-886 ink from Shenzhen Yancaiyi Technology Co., Ltd., and the ink layer thickness was 0.002mm.
[0051] The LDPE membrane is Yanshan Petrochemical LD607 with a thickness of 0.075 mm.
[0052] Preparation examples of raw materials and / or intermediates
[0053] Preparation Example 1
[0054] A rare-earth modified carbon nanotube was prepared by the following method:
[0055] S1. The carbon nanotube raw material was purified by nitric acid and ball-milled in a stainless steel ball mill for 2 hours to obtain pretreated carbon nanotubes; S2. A neodymium chloride solution with ethanol as solvent was prepared, the pH of the solution was adjusted to 6 with nitric acid, and then the pretreated carbon nanotubes were added for soaking and ultrasonic treatment at 300W for 15 hours. Finally, the carbon nanotubes were removed and dried to obtain rare earth modified carbon nanotubes.
[0056] Note: The concentration of neodymium chloride solution is 3.5 mol / mL, and the mixing ratio of pretreated carbon nanotubes and neodymium chloride solution is 1050 mL: 1 mg. The diameter of the carbon nanotube raw material is 20 nm and the length is 10 μm.
[0057] Preparation Example 2
[0058] A rare earth modified carbon nanotube differs from preparation example 1 in that the concentration of the neodymium chloride solution is 2.5 mol / mL, and the mixing ratio of the pretreated carbon nanotubes and the neodymium chloride solution is 900 mL: 1 mg.
[0059] Preparation Example 3
[0060] A rare earth modified carbon nanotube differs from preparation example 1 in that the concentration of the neodymium chloride solution is 4.5 mol / mL, and the mixing ratio of the pretreated carbon nanotubes and the neodymium chloride solution is 1200 mL: 1 mg.
[0061] Preparation Example 4
[0062] A rare earth modified carbon nanotube differs from preparation example 1 in that the carbon nanotube raw material has a diameter of 10 nm and a length of 0.5 μm.
[0063] Preparation Example 5
[0064] A rare earth modified carbon nanotube differs from preparation example 1 in that the carbon nanotube raw material has a diameter of 30 nm and a length of 20 μm.
[0065] Example
[0066] Example 1
[0067] A packaging film is prepared by hot stamping a gold foil transfer layer, a temperature-regulating layer, an ink layer, and an LDPE film layer, which are sequentially laminated from top to bottom. The raw materials used to prepare the temperature-regulating layer and their corresponding weights are shown in Table 1. The packaging film is prepared through the following steps:
[0068] (1) Prepare raw materials containing silicone acrylic emulsion, polyethylene glycol, deionized water, thickener, leveling agent, defoamer, rare earth modified carbon nanotubes and alumina-based porous ceramic powder according to the formula.
[0069] (2) After stirring and mixing the silicone acrylic emulsion, polyethylene glycol and deionized oil in step (1), add thickener, rare earth modified carbon nanotubes and alumina-based porous ceramic powder and continue stirring and mixing. Finally, add leveling agent and defoamer and mix evenly to obtain temperature-sensitive regulating layer material.
[0070] (3) Print an ink layer on the LDPE film layer, coat the surface of the ink layer with a temperature-sensitive regulating layer, dry and form it, and then combine it with the gold foil transfer layer to obtain a composite film. Finally, after hot stamping the composite film, a packaging film is obtained.
[0071] Note: In step (3), the coating amount of the temperature-sensing conditioning layer is 7 g / m². 2After coating, the drying temperature was 85℃ and the drying time was 7.5 min. The thickener was sodium carboxymethyl cellulose. The leveling agent was carboxymethyl cellulose. The defoamer was stearic acid. The rare earth modified carbon nanotubes were obtained in Preparation Example 1. The particle size of the alumina-based porous ceramic powder was 3 μm. For hot stamping, a zinc laser-engraved template was used as the hot stamping plate. The zinc laser-engraved template was heated to 140℃, and then the hot stamping foil was heated using the zinc laser-engraved template, causing the gold powder layer of the hot stamping foil to pass through the gold foil transfer layer to complete the hot stamping process.
[0072] Example 2-3
[0073] A packaging film differs from Example 1 in that the raw materials used to prepare the temperature-sensing regulating layer and their corresponding weights are shown in Table 1.
[0074] Table 1. Raw materials and their weight percentages (kg / part) used in the preparation of the temperature-sensing regulating layer in Examples 1-3.
[0075] raw material Example 1 Example 2 Example 3 silicone-acrylic emulsion 37.5 30 45 polyethylene glycol 1.5 1 2 Deionized water 12.5 10 15 Thickener 5 4 6 Leveling agent 0.2 0.1 0.3 Defoamer 0.2 0.1 0.3 Rare earth modified carbon nanotubes 4.5 3 6 Alumina-based porous ceramic powder 3.5 2 5
[0076] Example 4
[0077] A packaging film, differing from Example 1, in that, in step (3), the coating amount of the temperature-sensing regulating layer is 6 g / m². 2 After coating, the drying temperature is 80℃ and the drying time is 10 minutes.
[0078] Example 5
[0079] A packaging film, differing from Example 1, in that, in step (3), the coating amount of the temperature-sensing regulating layer is 8 g / m². 2 After coating, the drying temperature is 90℃ and the drying time is 5 minutes.
[0080] Example 6
[0081] A packaging film, which differs from Example 1 in that the rare earth modified carbon nanotubes were obtained in Preparation Example 2.
[0082] Example 7
[0083] A packaging film, which differs from Example 1 in that the rare earth modified carbon nanotubes were obtained in Preparation Example 3.
[0084] Example 8
[0085] A packaging film, which differs from Example 1 in that the rare earth modified carbon nanotubes were obtained in Preparation Example 4.
[0086] Example 9
[0087] A packaging film, which differs from Example 1 in that the rare earth modified carbon nanotubes were obtained in Preparation Example 5.
[0088] Example 10
[0089] A packaging film, which differs from Example 1 in that the alumina-based porous ceramic powder has a particle size of 1 μm.
[0090] Example 11
[0091] A packaging film, which differs from Example 1 in that the alumina-based porous ceramic powder has a particle size of 5 μm.
[0092] Example 12
[0093] A packaging film differs from Example 1 in that the total amount of rare earth modified carbon nanotubes and alumina-based porous ceramic powder remains unchanged, while the weight ratio of rare earth modified carbon nanotubes and alumina-based porous ceramic powder is adjusted to 5:3.
[0094] Comparative Example
[0095] Comparative Example 1
[0096] A packaging film, which differs from Example 1 in that rare earth modified carbon nanotubes are not used in the raw materials used to prepare the temperature-sensing regulating layer.
[0097] Comparative Example 2
[0098] A packaging film, which differs from Example 1 in that the raw materials used in the preparation of the temperature-sensing regulating layer do not include alumina-based porous ceramic powder.
[0099] Comparative Example 3
[0100] A packaging film, which differs from Example 1, does not use rare earth modified carbon nanotubes and alumina-based porous ceramic powder in the raw materials used to prepare the temperature-sensing regulating layer.
[0101] Comparative Example 4
[0102] A packaging film differs from Example 1 in that rare earth modified carbon nanotubes are replaced with carbon nanotube raw materials.
[0103] Comparative Example 5
[0104] A packaging film, which differs from Comparative Example 4 in that the raw materials used in the preparation of the temperature-sensing regulating layer do not include alumina-based porous ceramic powder.
[0105] Performance testing test samples: The packaging films obtained in Examples 1-12 were used as test samples 1-12, and the packaging films obtained in Comparative Examples 1-5 were used as control samples 1-5.
[0106] Test Method: AOI (Automated Optical Inspection) equipment was used to automatically inspect the printed images and text using optical principles. The AOI equipment illuminates the printed images and text with a light source, and the reflected light is collected by an optical lens and fed into a computer. The computer software then analyzes the color differences or grayscale ratios of the images to determine the quality and defects of the printed images and text. The specific operation is as follows:
[0107] (a) Light source illumination: AOI equipment uses a light source to illuminate the printed graphics to ensure that the image is clearly visible;
[0108] (ii) Image acquisition: The reflected light from the printed graphics is captured by an optical lens and fed into a computer to form a digital image;
[0109] (III) Image Processing: Computer software analyzes and processes the acquired images, and comprehensively judges the phenomenon of blurry or hazy images and text through color difference, grayscale ratio, design rule detection (DRC) and pattern recognition;
[0110] (iv) Results output: Display the test results on the monitor and mark the defect locations;
[0111] Finally, the proportion of the area where the defect is located is calculated. The larger the proportion, the more serious the blurring and haziness of the image. The test results of test samples 1-12 and control samples 1-5 are recorded in Table 2.
[0112] Table 2 Test results of test samples 1-12 and control samples 1-5
[0113]
[0114]
[0115] Combined with Examples 1 and Comparative Examples 1-3 and Table 2, it can be seen that by setting a temperature-sensing adjustment layer and compounding rare earth modified carbon nanotubes with alumina-based porous ceramic powder, the uniformity of heat transfer during hot stamping can be significantly improved. As a result, the packaging film obtained after the above tests shows that the proportion of defective areas is relatively low, indicating that the phenomenon of blurred or hazy images after hot stamping is relatively mild. It was also found that without rare-earth modified carbon nanotubes and alumina-based porous ceramic powder, the temperature-sensing regulating layer could not perform thermal conduction and thermal dispersion. In this case, the proportion of the defect area was significantly higher, and the phenomenon of blurry and hazy images was more serious. On this basis, using either rare-earth modified carbon nanotubes or alumina-based porous ceramic powder can improve thermal conduction and thermal dispersion, and improve the phenomenon of blurry and hazy images. However, in terms of the proportion of the defect area, the improvement effect is relatively limited. Moreover, the sum of the improvement effects brought by each is far less than that of the combination of the two. It can be seen that rare-earth modified carbon nanotubes and alumina-based porous ceramic powder play a significant role in improving the temperature-sensing regulating layer, with 1+1>2. Combined with Comparative Examples 4-5 and Table 2, it can be seen that if rare earth modified carbon nanotubes are replaced with carbon nanotube raw materials, the effect of carbon nanotube raw materials is far less than that of rare earth modified carbon nanotubes. Furthermore, the combination of carbon nanotube raw materials and alumina-based porous ceramic powder is merely a simple superposition of effects. Therefore, it is evident that the combination of rare earth modified carbon nanotubes and alumina-based porous ceramic powder is indispensable and is the guarantee for obtaining high-quality hot stamping packaging film.
[0116] Combining Examples 1 and 4-5 with Table 2, it can be seen that in step (3), the coating amount of the temperature-sensing regulating layer is 6-8 g / m². 2 After coating, the drying temperature is 80-90℃ and the drying time is 5-10min. This allows the rare earth modified carbon nanotubes and alumina-based porous ceramic powder in the temperature-sensing layer to fully cooperate and exert excellent corresponding effects. After the above tests, the proportion of the defective area of the obtained packaging film is also relatively stable and excellent.
[0117] Combining Examples 1 and 6-9 with Table 2, it can be seen that in the preparation of rare earth modified carbon nanotubes, the concentration of neodymium chloride solution is 2.5-4.5 mol / mL, the diameter of the carbon nanotube raw material is 10-30 nm, the length is 0.5-20 μm, and the mixing ratio of pretreated carbon nanotubes and neodymium chloride solution is (900-1200) mL:1 mg. This allows the obtained rare earth modified carbon nanotubes to form a relatively stable combination with alumina-based porous ceramic powder.
[0118] Combining Examples 1 and 10-11 with Table 2, it can be seen that when the particle size of the alumina-based porous ceramic powder is 1-5 μm, it meets the requirements for the application of the temperature-sensing regulating layer and can form an excellent and stable complex system with rare earth modified carbon nanotubes, thereby exhibiting excellent thermal conductivity and thermal dispersibility.
[0119] Combining Examples 1 and 12 with Table 2, it can be seen that when the weight ratio of rare earth modified carbon nanotubes to alumina-based porous ceramic powder is 5:3, a temperature-sensing regulating layer with better application quality can be obtained, and the proportion of the defective area in the obtained packaging film after the above tests is also relatively low.
[0120] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A packaging film, characterized in that, The composite film is made by sequentially bonding a gold foil transfer layer, a temperature-regulating layer, an ink layer, and an LDPE film layer from top to bottom. An ink layer is printed on the LDPE film layer, and a temperature-regulating layer material is coated onto the surface of the ink layer. After drying and shaping, the ink layer is laminated with the gold foil transfer layer to obtain a composite film. Finally, the composite film is hot-stamped to obtain the final product. The temperature-regulating layer is made from the following raw materials in parts by weight: 30-45 parts of silicone-acrylic emulsion; 1-2 parts polyethylene glycol; 10-15 parts deionized water; Thickener 4-6 parts; Leveling agent 0.1-0.3 parts; Defoamer 0.1-0.3 parts; Rare earth modified carbon nanotubes, 3-6 parts; 2-5 parts of alumina-based porous ceramic powder; The rare earth modified carbon nanotubes were prepared by the following method: S1. The carbon nanotube raw material is purified by acid and then ball-milled to obtain pretreated carbon nanotubes; S2. Prepare a neodymium chloride solution with ethanol as solvent, adjust the pH value of the solution with nitric acid, then add the pretreated carbon nanotubes for soaking and ultrasonic treatment, and finally take them out and dry them to obtain rare earth modified carbon nanotubes. The carbon nanotube raw material has a diameter of 10-30 nm and a length of 0.5-20 μm; the alumina-based porous ceramic powder has a particle size of 1-5 μm.
2. The packaging film according to claim 1, characterized in that: The weight ratio of the rare earth modified carbon nanotubes to the alumina-based porous ceramic powder is 5:
3.
3. The packaging film according to claim 1, characterized in that: The thickener is one or a combination of several of sodium starch phosphate, sodium polyacrylate, and sodium carboxymethyl cellulose.
4. The packaging film according to claim 1, characterized in that: The leveling agent is one or a combination of polydimethylsiloxane and polyacrylic acid.
5. The packaging film according to claim 1, characterized in that: The defoamer is one or a combination of several of emulsified silicone oil, polyoxypropylene glycerol ether, and stearic acid.
6. The method for preparing the packaging film according to any one of claims 1-5, characterized in that: Includes the following steps: (1) Prepare raw materials containing silicone acrylic emulsion, polyethylene glycol, deionized water, thickener, leveling agent, defoamer, rare earth modified carbon nanotubes and alumina-based porous ceramic powder according to the formula; (2) After stirring and mixing the silicone acrylic emulsion, polyethylene glycol and deionized oil in step (1), add thickener, rare earth modified carbon nanotubes and alumina-based porous ceramic powder and continue stirring and mixing. Finally, add leveling agent and defoamer and mix evenly to obtain temperature-sensitive regulating layer material. (3) Print an ink layer on the LDPE film layer, coat the surface of the ink layer with a temperature-sensitive regulating layer, dry and form it, and then combine it with the gold foil transfer layer to obtain a composite film. Finally, after hot stamping the composite film, a packaging film is obtained.
7. The method for preparing the packaging film according to claim 6, characterized in that: In the operation of step (3), the coating amount of the temperature sensing adjusting layer is 6-8 g / m 2 , and the drying temperature after coating is 80-90°C, and the drying time is 5-10 min.