Magnetized packaging material and method of making same

Abstract

The application relates to the technical field of packaging materials, and discloses a magnetic packaging material manufacturing method, which comprises the following steps: Step 1, providing a polyester film and paper material as a base material layer, and performing surface treatment on the base material layer; Step 2, preparing magnetic ink, wherein the magnetic ink comprises nano-scale ferroferric oxide magnetic powder, an adhesive and a solvent; Step 3, coating a magnetic ink layer on the base material layer, adopting a multi-layer coating process, and performing drying treatment after each layer is coated; Step 4, performing magnetization treatment on the base material layer coated with the magnetic ink layer by using a magnetization mold to form a magnetization pattern; and Step 5, coating a protective layer on the outer surface of the magnetic ink layer. By using nano-scale ferroferric oxide magnetic powder and optimizing the formula of the magnetic ink, the magnetized packaging material can generate higher and more uniform magnetic field intensity, so that the material performs better in the applications of anti-fake, information storage, intelligent labels and the like, and can better meet the high-precision magnetic requirements.

Description

Technical Field

[0001] This invention relates to the field of packaging materials technology, specifically to a magnetized packaging material and its manufacturing method. Background Technology

[0002] In today's society, with the development of the logistics industry and the increasing demand for anti-counterfeiting measures, magnetized packaging materials are being used more and more widely in the fields of smart packaging, anti-counterfeiting labels, and information storage. These materials are typically created by coating a substrate with an ink layer containing magnetic powder and then magnetizing it, forming packaging materials with specific magnetic field properties. This type of material can play an important role in intelligent identification, logistics tracking, and anti-counterfeiting detection.

[0003] Traditional magnetized packaging materials mainly use single-layer plastic film as the base material, typically polyethylene (PE), polypropylene (PP), or polyester (PET) film. Although these materials are low in cost and simple to process, they have many shortcomings in terms of mechanical strength, durability, magnetic strength, and coating uniformity.

[0004] First, the magnetic ink formulations used in traditional magnetized packaging materials are relatively simple, with magnetic powder particles having a large particle size, typically between 100 and 200 nanometers. Due to the large particle size of the magnetic powder, the magnetic components in the ink are difficult to form a uniform magnetic field after coating, resulting in low magnetic field strength and poor uniformity, which makes it difficult to meet the requirements of high-precision applications.

[0005] Secondly, traditional processes typically employ corona treatment or simple chemical treatments to improve the adhesion between the substrate and the ink. However, these methods have limited effectiveness and are prone to peeling or delamination of the coating, especially when affected by external environmental factors such as humidity and temperature changes, resulting in poor material performance stability.

[0006] Furthermore, traditional magnetized packaging materials also have shortcomings in terms of protective performance. Due to the use of a single-layer substrate, the material's barrier effect against external environmental factors such as moisture and oxygen is poor, affecting the durability of the packaging material and the shelf life of the product. At the same time, the optical properties of traditional materials are poor, failing to meet the demands of the high-end market for packaging aesthetics.

[0007] Although existing technologies have made some progress in the research and application of magnetized packaging materials, some technical bottlenecks still need to be overcome. Specifically, the main shortcomings of existing technologies include: Poor particle size and dispersibility of magnetic inks: Existing magnetic inks usually use magnetic powder with a large particle size, resulting in insufficient magnetic field strength and uneven distribution. At the same time, due to poor dispersibility, the ink is prone to sedimentation and agglomeration, which affects the coating effect.

[0008] Inadequate substrate treatment technology: Traditional surface treatment techniques cannot adequately improve the adhesion between the substrate and the ink, leading to easy peeling or delamination of the coating layer, which affects the long-term stability of the material.

[0009] Limitations of coating process and magnetization technology: Existing coating and magnetization processes are relatively basic and it is difficult to achieve high-precision and high-uniformity magnetic patterns. In particular, in the magnetization process of multi-layer coating and complex patterns, there are often problems of process instability.

[0010] Limited protective performance and appearance of materials: Existing magnetized packaging materials are lacking in the ability to block moisture, oxygen and light, resulting in insufficient durability and making it difficult to meet the higher requirements of the high-end market for the appearance and protective function of packaging materials. Summary of the Invention

[0011] To address the shortcomings of existing technologies, this invention provides a magnetized packaging material and its manufacturing method, solving the problems of insufficient magnetism, uneven coating, poor adhesion, and limited protective performance in existing technologies.

[0012] To achieve the above objectives, the present invention provides the following technical solution: a magnetized packaging material, comprising: A substrate layer, wherein the substrate layer is a polyester film and a paper material; A magnetic ink layer is coated on at least one side of the substrate layer, the magnetic ink layer comprising nano-sized iron oxide magnetic powder, a binder and a solvent; A magnetized pattern, the magnetized pattern being formed in the magnetic ink layer.

[0013] Preferably, the thickness of the substrate layer is 40-60 micrometers, and the substrate layer is a surface-treated polyester film.

[0014] Preferably, the magnetic ink layer comprises the following components by weight percentage: Magnetic powder: 40%-50%, wherein the magnetic powder is iron oxide with an average particle size of 50-100 nanometers; Adhesive: 20%-35%, wherein the adhesive is polyvinyl butyral; Solvent: 15%-30%, wherein the solvent is anhydrous ethanol; Dispersant: 1%-5%.

[0015] Preferably, the thickness of the magnetic ink layer is 20-80 micrometers, and the magnetic field strength of the magnetized pattern is 1.0-2.0T.

[0016] Preferably, a protective layer is coated on the outer surface of the magnetic ink layer, the protective layer being polyurethane with a coating thickness of 10-20 micrometers.

[0017] A method for manufacturing magnetized packaging material includes the following steps: Step 1: Provide polyester film and paper material as substrate layer, and perform surface treatment on the substrate layer; Step 2: Prepare magnetic ink, wherein the magnetic ink comprises nano-sized iron oxide magnetic powder, binder and solvent; Step 3: Apply a magnetic ink layer to the substrate layer using a multi-layer coating process, and dry each layer after coating. Step 4: Magnetize the substrate layer coated with magnetic ink using a magnetization mold to form a magnetized pattern; Step 5: Apply a protective layer to the outer surface of the magnetic ink layer and then cure it.

[0018] Preferably, the surface treatment in step one is plasma treatment, with a treatment time of 20-40 seconds and a treatment power of 80-120W.

[0019] Preferably, the magnetic ink formulation in step two comprises the following components by weight percentage: Magnetic powder: 40%-50%, wherein the magnetic powder is iron oxide with an average particle size of 50-100 nanometers; Adhesive: 20%-35%, wherein the adhesive is polyvinyl butyral; Solvent: 15%-30%, wherein the solvent is anhydrous ethanol; Dispersant: 1%-5%.

[0020] Preferably, the multilayer coating process in step three includes coating a magnetic ink layer onto at least one side of the substrate layer, with the initial coating thickness being 20 micrometers, followed by hot air drying at 60°C for 2 minutes; the multilayer coating includes three or more coating and drying processes, with each coating followed by hot air drying at 60°C for 2-5 minutes, and the final coating being dried at 80°C for 5 minutes.

[0021] Preferably, the magnetization process in step four is carried out using a neodymium iron boron permanent magnet mold, wherein the pressure applied by the mold is 2-3 MPa and the magnetization time is 8-12 seconds.

[0022] This invention provides a magnetized packaging material and its manufacturing method. It has the following beneficial effects: 1. By using nano-sized iron oxide magnetic powder and an optimized magnetic ink formula, the magnetized packaging material of this invention can generate a higher magnetic field strength and significantly improved magnetic field uniformity. This enhanced magnetism makes the material perform better in applications such as anti-counterfeiting, information storage, and smart labels, and can better meet the requirements of high-precision magnetism.

[0023] 2. This invention significantly improves the adhesion of magnetic ink to the substrate layer through plasma surface treatment, reducing the risk of coating peeling or delamination. Furthermore, using high-performance polyester film as the substrate further enhances the material's mechanical strength and anti-aging properties, enabling the packaging material to maintain its structural integrity and functionality under various harsh environments.

[0024] 3. This invention employs optimized coating and drying processes, combined with the use of rapidly volatile solvents, significantly improving production efficiency and shortening the drying time after coating. Simultaneously, through multi-layer coating technology, the magnetic ink layer achieves the desired thickness and uniformity, thereby ensuring product consistency and quality stability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the material structure of the present invention; Figure 2 This is a schematic diagram of the method flow of the present invention.

[0026] Legend: 1. Substrate layer; 2. Magnetic ink layer; 3. Magnetized pattern. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0028] Please see the appendix Figure 1 -Appendix Figure 2 This invention provides a magnetized packaging material and its manufacturing method, comprising the following steps: I. Selection and Treatment of Substrate Layer 1. Selection of substrate layer In this embodiment, the first substrate layer is a 50-micron-thick polyester film (PET), and the second layer is a paper material. This is because PET film maintains good mechanical strength and dimensional stability under both room temperature and high temperature conditions, and is not easily deformed or degraded, making it very suitable for multi-layer coating processes. The paper material provides environmental friendliness and additional mechanical support, increasing the product's sustainability and range of applications. When selecting PET film as the substrate, it should be ensured that its surface is smooth and free of obvious scratches to prevent affecting the adhesion of subsequent inks.

[0029] 2. Surface treatment of the substrate layer In this embodiment, plasma surface treatment technology is used to enhance the adhesion of magnetic ink to the polyester film surface. In actual operation, the polyester film is fixed on the worktable of the plasma treatment machine for surface treatment. Appropriate surface smoothing treatment is performed on the paper layer to ensure its surface is suitable for coating. The treatment parameters are set as follows: vacuum chamber pressure 0.05 Pa, treatment power 100 W, and treatment time 30 seconds. During this process, the plasma micro-etches the film surface, increasing surface roughness and forming polar groups such as hydroxyl or carboxyl groups on the surface. These groups can significantly improve the adhesion of the ink layer.

[0030] After the above treatment, the film surface exhibits better oleophilicity, which helps the ink to be evenly coated in the subsequent coating process and to form a strong bond with the substrate, thereby improving the durability and reliability of the magnetized packaging material.

[0031] II. Preparation of Magnetic Ink 1. Preparation of magnetic powder In this embodiment, the magnetic particles used are nano-sized iron(III) oxide (Fe3O4) magnetic powder, with a particle size controlled between 50-100 nanometers. To ensure the dispersibility and magnetic strength of the magnetic powder, it needs to be ultrasonically dispersed before use. Specifically, the magnetic powder is mixed with anhydrous ethanol at a ratio of 1:10 and placed in an ultrasonic disperser for 30 minutes at a frequency of 40 kHz. This treatment ensures the uniform dispersion of the magnetic powder in the solvent, preventing agglomeration and guaranteeing the uniformity of the magnetic powder during subsequent ink preparation.

[0032] 2. Preparation of Magnetic Ink In this embodiment, the magnetic ink was formulated according to the following recipe: 43% magnetic powder, 30% polyvinyl butyral (PVB) binder, 25% anhydrous ethanol solvent, and 2% nonylphenol polyoxyethylene ether dispersant. These components were mixed in a high-speed dispersant mixer at 2000 rpm for 60 minutes. The purpose of this process was to ensure that all components were uniformly mixed, especially that the magnetic powder was fully dispersed in the binder and solvent to form a stable suspension.

[0033] The mixed magnetic ink needs to be degassed to remove any air bubbles that may have been introduced during mixing, preventing bubble defects during subsequent coating. The degassed operation is performed in a vacuum degaussing device at a vacuum level of -0.08 MPa for 10 minutes. After treatment, the ink should be immediately sealed and stored to prevent the absorption of moisture and impurities from the air.

[0034] The magnetic ink prepared through the above steps has good fluidity and stability, and can be evenly spread on the surface of the substrate layer in the subsequent coating process to form a uniform magnetic layer.

[0035] III. Coating and Drying of Magnetic Ink 1. Initial coating In this embodiment, the coating process is performed using a gravure printing machine with a gravure roller having a depth of 30 micrometers to ensure uniform ink coating. During the initial coating, the magnetic ink is uniformly coated onto the surface-treated polyester film, with the coating thickness controlled at 20 micrometers. At this time, the coating speed of the coating machine is set to 2 m / min to ensure the uniformity and stability of the coating layer.

[0036] After coating, drying should be carried out immediately. The initial coating is dried using hot air drying equipment at a temperature of 60℃ for 2 minutes. Uniform airflow must be maintained during drying to prevent cracking or poor adhesion of the ink layer due to uneven heating.

[0037] 2. Multi-layer coating To enhance the magnetic field strength and thickness of the magnetic ink layer, a multi-layer coating process was employed in this embodiment. Specifically, after the initial coating has dried, at least two more coatings are applied, with each coating layer controlled to a thickness of 20 micrometers. Each coating layer is then dried. The drying temperature is sequentially set to 60°C, and the drying time is 2-5 minutes. After the final coating layer, the drying temperature is increased to 80°C, and the drying time is extended to 5 minutes to ensure that all coating layers are fully cured, forming a robust, integral magnetic ink layer.

[0038] Through a multi-layer coating process, the final magnetic ink layer has a total thickness of 60-80 micrometers, with strong interlayer bonding that prevents delamination or peeling. The optimized coating process endows the magnetic ink layer with excellent magnetic and mechanical properties, laying a solid foundation for subsequent magnetization treatment.

[0039] IV. Magnetization Treatment 1. Design and use of magnetization molds In this embodiment, the design of the magnetization mold is crucial, and its embedded neodymium iron boron permanent magnet array is key to achieving a precise magnetization pattern. The layout and polarity arrangement of the magnet array are determined during mold design based on the desired magnetization pattern. The mold's magnetic field strength is designed to be 1.5T, enabling effective magnetization of the magnetic ink layer in a relatively short time.

[0040] 2. Magnetization process flow In this embodiment, the dried coating substrate is laid flat on the worktable of the magnetizing mold, ensuring that the substrate and the mold surface are in smooth contact. A pressure of 2-3 MPa is applied by the hydraulic system to ensure that the substrate and the mold are in close contact. Then, the magnetization equipment is started, and the magnetization time is set to 10 seconds. During this process, the magnetic field generated by the magnet in the mold acts on the magnetic ink layer, causing the magnetic powder inside to align in a predetermined magnetization pattern.

[0041] After magnetization, the pressure is released slowly to prevent stress concentration in the substrate due to sudden pressure release, which could lead to damage. The magnetized substrate is then removed and transferred to the next process. Through the above magnetization process, the magnetic powder in the magnetic ink layer can be precisely arranged into a predetermined pattern, ensuring that the magnetic field strength of the magnetized pattern reaches 1.0-2.0T, meeting the needs of different application scenarios.

[0042] V. Magnetic Pattern Detection and Protective Coating 1. Detection of magnetic patterns In this embodiment, the magnetized substrate will proceed to the inspection process. A Hall effect sensor array with a spacing of 1 mm is used to inspect the magnetized pattern, enabling precise measurement of the magnetic field strength and direction. During inspection, the substrate passes through the sensor array at a constant speed, and the sensors automatically record the magnetic field data at each inspection point.

[0043] The test data is analyzed in real time by a computer system. If the magnetic field strength and direction deviate from the predetermined standard by more than 5%, the system will automatically mark that area as a defective product and record the corresponding information. Through a rigorous testing process, it is ensured that the magnetization pattern of each piece of magnetized packaging material meets the design requirements, guaranteeing the consistency of product quality.

[0044] 2. Coating and curing of the protective layer To protect the magnetic ink layer from external environmental influences, in this embodiment, a polyurethane (PU) protective layer is coated onto the outer surface of the magnetic ink layer. The coating process uses an automated coating machine, and the thickness of the protective layer is controlled to be 10-20 micrometers. After coating, a UV curing device is used for curing, with a curing time of 3-5 minutes. Through UV curing, a robust protective film is formed on the surface of the ink layer, effectively preventing the effects of moisture, oxygen, and mechanical abrasion on the magnetic ink layer.

[0045] After being coated with a protective layer and cured, the magnetized packaging material possesses long-term durability and stability, meeting the needs of various application scenarios, such as anti-counterfeiting, information storage, and smart packaging. Example

[0046] This invention provides a magnetized packaging material and its manufacturing method, comprising the following steps: Composite structure design of substrate layer 1. Composition of the composite substrate layer In this embodiment, the substrate layer is composed of a double-layer composite structure, specifically including: First layer: a 30-micron thick polyester film (PET).

[0047] The second layer is an aluminum-coated thin film with a thickness of 20 micrometers.

[0048] Third layer: Paper material Polyester film primarily provides the material with mechanical strength, heat resistance, and dimensional stability, while aluminized film is known for its excellent barrier properties and optical reflective properties. By combining these two types of films, a multifunctional composite substrate layer is formed.

[0049] 2. Preparation process of composite substrate layer In this embodiment, the preparation of the composite substrate layer involves the following steps: Step 1: Material Preparation: First, prepare the required polyester film, paper material, and metallized film. The polyester film should have a uniform thickness and a smooth surface, while the metallized film should have a high-quality metallized layer without peeling or damage.

[0050] Step 2, Lamination Process: The polyester film, paper material, and aluminized film are bonded together using hot pressing or adhesive bonding methods. The specific steps are as follows: Hot-press lamination: Two layers of film are hot-pressed using a hot press. The hot-pressing temperature is controlled between 150℃ and 180℃, and the hot-pressing time is 5-10 seconds. During the hot-pressing process, ensure that the pressure is evenly distributed to prevent air bubbles or delamination between the composite layers.

[0051] Adhesive lamination: If adhesive lamination is used, first uniformly coat a layer of polymer adhesive on the surface of the polyester film, then laminate the aluminized film to it, apply pressure through a pressure roller, and finally dry and cure the adhesive at 60°C for 10 minutes.

[0052] Through the above composite process, the final substrate layer has good structural strength and composite performance, with an overall thickness of 50 micrometers. It retains the mechanical properties of polyester film while enhancing the material's protective function and optical properties.

[0053] Surface treatment of substrate layer 1. Plasma treatment In this embodiment, after the composite substrate layer is laminated, it needs to undergo surface treatment to improve its adhesion to the magnetic ink. Plasma surface treatment remains the preferred process, and the specific steps are as follows: Equipment: A plasma treatment machine is used, with the composite substrate layer laid flat on the machine's worktable.

[0054] Processing parameters: The vacuum chamber pressure is set to 0.05 Pa, the processing power to 100 W, and the processing time to 30 seconds. During the processing, plasma acts on the surface of the composite substrate layer, increasing its surface roughness and introducing polar groups (such as hydroxyl and carboxyl groups) to enhance the adhesion of the magnetic ink.

[0055] The treated composite substrate layer has a more active surface, which can significantly improve the coating quality of magnetic inks and the stability of the final product.

[0056] Advantages of composite substrate layers In this embodiment, by combining the polyester film with the aluminized film, the substrate layer exhibits significant advantages in the following aspects: 1. Protective performance: The aluminum-coated film has excellent barrier properties, which can effectively prevent external environmental factors such as water vapor and oxygen from corroding the magnetic ink layer and extend the service life of packaging materials.

[0057] 2. Optical properties: The aluminum coating has high reflectivity, which gives the surface of the composite substrate a metallic luster, not only enhancing the aesthetics of the material but also making it more attractive in the packaging of high-end products.

[0058] 3. Mechanical properties: Through the composite structure, the overall mechanical properties of the substrate layer are improved, enabling it to withstand greater mechanical stress and external impact, making it suitable for various complex packaging environments.

[0059] Application of composite substrate layer in magnetized packaging materials In this embodiment, after the composite substrate layer undergoes surface treatment, it continues to be processed according to the steps in the aforementioned embodiments, including magnetic ink coating and drying, magnetization treatment, and protective layer coating, ultimately forming a magnetized packaging material with high protective properties, high optical reflectivity, and excellent mechanical strength.

[0060] By employing a composite substrate layer design, the magnetized packaging material in this embodiment maintains its original magnetic function while further enhancing its protective performance and appearance. Especially under harsh environmental conditions, the material can retain its magnetic and physical properties for extended periods, prolonging product lifespan and providing broader application possibilities.

[0061] Unlike Example 1, Example 2 further optimizes the structure of the substrate layer. By adopting a multifunctional composite structure, the magnetized packaging material has better overall performance, especially in terms of protection and optical properties. Example

[0062] This invention provides a magnetized packaging material and its manufacturing method, comprising the following steps: Formulation of magnetic ink 1. Composition ratio of magnetic ink In this embodiment, the improved formulation of the magnetic ink includes the following components by weight percentage: Magnetic powder: 50% (Fe3O4, average particle size 60-80 nanometers); Adhesive: 25% (polyurethane resin, with higher flexibility and adhesion); Solvent: 20% (isopropanol, which has a fast evaporation rate and is suitable for high-speed coating processes). Dispersant: 5% (a fluorinated surfactant that can significantly reduce the agglomeration of magnetic powder in ink).

[0063] 2. Selection and processing of magnetic powder In this embodiment, the magnetic powder used is iron(III) oxide with a particle size of 60-80 nanometers. Compared with the magnetic powder with a particle size of 50-100 nanometers in the previous embodiment, the optimized control of the particle size within the range of 60-80 nanometers results in better dispersion of the magnetic powder in the magnetic ink and more uniform arrangement during the magnetization process, thereby improving the magnetic field strength of the magnetic ink layer.

[0064] Before use, the magnetic powder still needs to undergo ultrasonic dispersion treatment to ensure sufficient dispersion in the solvent. The specific procedure is as follows: mix the magnetic powder with isopropanol at a ratio of 1:10, and treat the mixture in an ultrasonic disperser for 30 minutes at an ultrasonic frequency of 40 kHz. This treatment step helps to avoid agglomeration of the magnetic powder and ensures its uniform distribution during ink preparation.

[0065] 3. Adhesive Selection In this embodiment, the adhesive used is polyurethane resin (PU), which has higher flexibility and adhesion compared to polyvinyl butyral (PVB) in the previous embodiments. PU resin can form a more robust film layer in the coated magnetic ink layer, enhancing the adhesion between the magnetic ink and the substrate, and providing better crack resistance.

[0066] 4. Solvent Selection Isopropanol was chosen as the solvent because it evaporates faster than ethanol, making it suitable for high-speed coating processes. The use of isopropanol significantly shortens ink drying time, improves production efficiency, and reduces uneven ink layer thickness caused by uneven solvent evaporation during coating.

[0067] 5. Selection of dispersant To improve the dispersion stability of magnetic powder in the ink, 5% of a fluorinated surfactant was added in this embodiment. This type of dispersant has low surface tension and excellent wettability, which can significantly reduce the agglomeration of magnetic powder, resulting in a more uniform distribution of the powder in the ink and thus forming a uniform coating layer.

[0068] Preparation process of magnetic ink 1. Mixing and stirring In this embodiment, the preparation process of the magnetic ink is as follows: First, mix the polyurethane resin and isopropanol in a high-speed dispersing mixer for 30 minutes to ensure the adhesive is completely dissolved.

[0069] Next, slowly add the ultrasonically treated magnetic powder and continue stirring at 2000 rpm for 60 minutes to ensure that the magnetic powder is evenly distributed in the solution.

[0070] Finally, add a fluorinated surfactant and stir for 15 minutes to further improve the dispersibility and stability of the ink.

[0071] 2. Degassing and filtration To prevent air bubbles from forming during coating, the mixed magnetic ink undergoes vacuum degassing at -0.08 MPa for 10 minutes. After degassing, the ink is filtered through a 200-mesh stainless steel filter to remove any potential particulate impurities and ensure its purity.

[0072] The magnetic ink obtained through the above preparation process has excellent flowability, dispersibility and uniformity, making it suitable for high-precision coating processes.

[0073] Coating and magnetization of magnetic inks 1. Coating process In this embodiment, the improved magnetic ink is coated onto polyester film and paper materials after the substrate layer has undergone surface treatment. A gravure printing machine is used, and the coating thickness is controlled between 20-80 micrometers, with the specific thickness depending on the application requirements.

[0074] After coating, the ink layer is dried at 60°C for 2 minutes. Due to the rapid volatility of isopropanol solvent, the drying process is faster than that of ethanol solvent in the previous examples, reducing waiting time in the production process and ensuring the uniformity and stability of the coating layer.

[0075] 2. Magnetization treatment The magnetization process in this embodiment is similar to that in the aforementioned implementation, still using a neodymium iron boron permanent magnet mold to magnetize the substrate coated with magnetic ink. The magnetization time is 8-12 seconds, and the applied pressure is 2-3 MPa. Through the optimized magnetic ink formulation, the magnetized magnetic pattern can generate a higher magnetic field strength, and the magnetic field uniformity is also significantly improved.

[0076] Unlike Example 1, this example further optimizes the formulation of the magnetic ink, aiming to improve the magnetic strength, dispersion stability and coating uniformity of the magnetic ink, thereby enhancing the overall performance of the magnetized packaging material.

[0077] Table 1: Comparison of Experimental Data from Examples

[0078] Substrate layer performance: Example 2 employs a double-layer composite substrate structure, exhibiting superior performance in terms of protection, optical reflectivity, and mechanical strength. In particular, the aluminum plating layer significantly enhances the material's barrier properties and optical reflectivity, making it suitable for high-end packaging applications. In contrast, Examples 1 and 3 both utilize a single-layer PET film. While maintaining good mechanical strength, they are less effective in terms of optical reflectivity and protection.

[0079] Magnetic ink properties: Example 3 optimized the formulation of the magnetic ink, particularly by using smaller-particle-size iron oxide magnetic powder, polyurethane resin binder, and fluorinated dispersant, which significantly improved the magnetic field strength and uniformity of the ink, and also resulted in better material toughness and wear resistance. Although Example 2 increased the magnetic powder content, its magnetic field uniformity was slightly inferior to that of Example 3.

[0080] Coating and magnetization properties: In Example 3, the coating drying time and temperature settings are more precise. Combined with the rapid evaporation characteristics of isopropanol solvent, the uniformity and magnetization effect of the ink layer are optimized, especially achieving higher magnetic field strength and uniformity after magnetization. In contrast, the drying times in Examples 1 and 2 are longer. Although they can also achieve good coating results, their production efficiency is slightly lower than that of Example 3.

[0081] Material durability: Example 2, due to its composite substrate and high magnetic powder content, exhibits the best performance in terms of protective properties and mechanical strength, and also demonstrates longer durability in accelerated aging tests, making it suitable for long-term applications in harsh environments. Example 3, through its optimized ink formulation, enhances the material's wear resistance and toughness, making it suitable for applications requiring high material durability.

[0082] In summary, through the comparison of the above embodiments and experimental data, the magnetized packaging material and its manufacturing method of the present invention provide a variety of optimization solutions for different application scenarios, which can meet the diverse needs of the market.

[0083] Comparative Example 1: This comparative example discloses a traditional magnetized packaging material and its manufacturing method, including the following steps: I. Selection of Substrate Layer 1. Substrate layer selection Traditional magnetized packaging materials typically use a single-layer plastic film as the substrate, with common materials including polyethylene (PE), polypropylene (PP), or polyester (PET) film. The thickness is generally between 30-50 micrometers. The substrate layer primarily provides the material's mechanical strength and printability, suitable for simple coating and processing techniques.

[0084] 2. Surface treatment In traditional processes, the surface treatment of the substrate layer is relatively simple, typically using corona treatment or chemical treatment to improve ink adhesion. Corona treatment introduces plasma under a high-voltage electric field to alter the surface energy of the material, making it easier for it to bond with the ink.

[0085] II. Preparation of Magnetic Ink 1. Selection of magnetic powder In traditional processes, magnetic inks typically use coarse-grained ferrite powders, such as magnetite (Fe3O4) or iron oxide (Fe2O3). The particle size of the magnetic powder is generally in the range of 100-200 nanometers. While larger particle sizes are easier to disperse, the magnetic field strength is relatively low, and the uniformity after coating is poor.

[0086] 2. Preparation of Magnetic Ink Traditional magnetic ink formulations are relatively simple, typically including: Magnetic powder: 20%-30%; Adhesives: commonly used are polyvinyl butyral (PVB) or acrylic resin, accounting for 40%-50%; Solvent: Use ethanol or isopropanol, accounting for 20%-30%; Additives: including leveling agents and anti-settling agents, to improve the stability of ink, accounting for 1%-2%.

[0087] These ingredients are mixed in a low-speed mixer for about 30 minutes. Traditional processes do not emphasize ultrasonic dispersion, which causes the magnetic powder to easily agglomerate in the ink, resulting in an uneven magnetic layer after coating.

[0088] III. Coating and Drying of Magnetic Ink 1. Initial coating In the production of traditional magnetized packaging materials, simple coating processes such as screen printing or gravure printing are typically used. The coating thickness is generally between 10-30 micrometers, followed by preliminary treatment through natural drying or simple hot air drying. The drying temperature is set at 50-60℃, and the drying time is 5-10 minutes. Due to the simplicity of the process, the resulting ink layer is often not uniform and exhibits uneven thickness.

[0089] 2. Multi-layer coating In traditional processes, the use of multilayer coating is relatively limited, usually only to increase magnetic strength. The operation of multilayer coating is the same as that of the initial coating, but due to the lower precision of the coating equipment, the interlayer adhesion is weak, and delamination or peeling is prone to occur.

[0090] IV. Magnetization Treatment 1. Use of magnetized molds In traditional processes, magnetization mold design is relatively simple, typically using low-strength ferrite magnets or neodymium iron boron magnets. The magnetic field strength is generally around 0.5-1.0 T, which can meet the needs of simple anti-counterfeiting and information storage applications.

[0091] 2. Magnetization process flow Traditional magnetization processes are relatively simple. The coated substrate is placed directly on a magnetization mold, and a small pressure (1-2 MPa) is applied. The magnetization time is usually set to 5-10 seconds. However, due to the limited magnetic field strength, the magnetized magnetic pattern has low strength and poor uniformity.

[0092] V. Magnetic Pattern Detection and Protective Coating 1. Detection of magnetic patterns In traditional processes, the detection of magnetic patterns is relatively simple, typically using manual or low-precision detection equipment, such as simple Hall effect sensors. The spacing between detection points is relatively large (2-3 mm), providing only rough measurements of magnetic field strength and direction, making it difficult to guarantee the accuracy of the pattern.

[0093] 2. Coating and curing of the protective layer Traditional magnetized packaging materials typically employ a simple coating process, using a transparent acrylic or polyethylene film for the protective layer. The layer thickness is generally between 5-10 micrometers, and curing is primarily done naturally or with hot air, with a relatively long curing time (10-20 minutes). This type of protective layer provides basic protection, but its durability and abrasion resistance are limited.

[0094] Table 2 Comparative Experiment Data Table

[0095] Substrate layer performance: The comparative example used a traditional single-layer polyethylene (PE) film, which has low mechanical strength and durability, and relatively poor optical reflection and protective properties.

[0096] Example 1 uses a higher-performance single-layer polyester film (PET), which exhibits better performance in terms of mechanical strength, durability and protective properties.

[0097] Magnetic ink properties: The magnetic ink in the comparative example used magnetite powder with a larger particle size, resulting in a lower magnetic field strength and poorer uniformity.

[0098] Example 1 significantly improved the magnetic field strength and uniformity by using smaller-sized iron oxide magnetic powder, and improved the ink adhesion through plasma treatment.

[0099] Coating and magnetization properties: The coating process in the comparative example is relatively simple, the coating thickness is thin and the drying time is long. The magnetic field strength of the magnetized mold is limited, resulting in a low magnetic field strength of the final product.

[0100] Example 1 significantly improved the magnetic field strength and coating uniformity through the use of a multi-layer coating process and a high-strength neodymium iron boron permanent magnet mold, and the magnetized material properties were superior to those of the comparative example.

[0101] Material durability: The comparative material has lower durability and performs poorly in accelerated aging tests, making it suitable for general short-term packaging applications.

[0102] Example 1 performed better in durability tests and is suitable for more demanding applications, especially those requiring stable magnetic performance over long periods.

[0103] In summary, the magnetized packaging material of Example 1 significantly outperforms the conventional magnetized packaging material of the comparative example in several key performance indicators. Example 1 demonstrates superior performance in mechanical strength, magnetic field strength, uniformity, and durability, making it suitable for demanding applications, while the conventional material of the comparative example is more suitable for cost-sensitive applications with lower performance requirements.

[0104] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A magnetized packaging material, characterized in that, include: Substrate layer (1), wherein the substrate layer is a polyester film and a paper material; Magnetic ink layer (2), wherein the magnetic ink layer is coated on at least one side of the substrate layer, and the magnetic ink layer comprises nano-sized iron oxide magnetic powder, binder and solvent; Magnetized pattern (3), the magnetized pattern being formed in the magnetic ink layer.

2. The magnetized packaging material according to claim 1, characterized in that, The thickness of the substrate layer is 40-60 micrometers, and the substrate layer is a surface-treated polyester film.

3. The magnetized packaging material according to claim 1, characterized in that, The magnetic ink layer comprises the following components by weight percentage: Magnetic powder: 40%-50%, wherein the magnetic powder is iron oxide with an average particle size of 50-100 nanometers; Adhesive: 20%-35%, wherein the adhesive is polyvinyl butyral; Solvent: 15%-30%, wherein the solvent is anhydrous ethanol; Dispersant: 1%-5%.

4. The magnetized packaging material according to claim 1, characterized in that, The thickness of the magnetic ink layer is 20-80 micrometers, and the magnetic field strength of the magnetized pattern is 1.0-2.0 T.

5. The magnetized packaging material according to claim 1, characterized in that, A protective layer is coated on the outer surface of the magnetic ink layer. The protective layer is polyurethane and has a coating thickness of 10-20 micrometers.

6. A method for manufacturing magnetized packaging material, characterized in that, Includes the following steps: Step 1: Provide polyester film and paper material as substrate layer (1), and perform surface treatment on the substrate layer; Step 2: Prepare magnetic ink, wherein the magnetic ink comprises nano-sized iron oxide magnetic powder, binder and solvent; Step 3: Apply a magnetic ink layer (2) to the substrate layer using a multi-layer coating process, and dry each layer after coating. Step 4: Magnetize the substrate layer coated with magnetic ink layer using a magnetization mold to form a magnetization pattern (3). Step 5: Apply a protective layer to the outer surface of the magnetic ink layer and then cure it.

7. A method for manufacturing magnetized packaging material according to claim 6, characterized in that, The surface treatment in step one is plasma treatment, with a treatment time of 20-40 seconds and a treatment power of 80-120 W.

8. A method for manufacturing magnetized packaging material according to claim 6, characterized in that, The magnetic ink formulation described in step two includes the following components by weight percentage: Magnetic powder: 40%-50%, wherein the magnetic powder is iron oxide with an average particle size of 50-100 nanometers; Adhesive: 20%-35%, wherein the adhesive is polyvinyl butyral; Solvent: 15%-30%, wherein the solvent is anhydrous ethanol; Dispersant: 1%-5%.

9. A method for manufacturing magnetized packaging material according to claim 6, characterized in that, Step 3, the multilayer coating process, includes coating a magnetic ink layer onto at least one side of the substrate layer. The thickness of the initial coating layer is 20 micrometers. After coating, it is dried with hot air at 60°C for 2 minutes. The multilayer coating includes three or more coating and drying processes. After each coating, it is dried with hot air at 60°C for 2-5 minutes. The drying temperature of the final coating layer is increased to 80°C, and the drying time is 5 minutes.

10. A method for manufacturing a magnetized packaging material according to claim 6, characterized in that, The magnetization process in step four is carried out using a neodymium iron boron permanent magnet mold, with the mold applying a pressure of 2-3 MPa and a magnetization time of 8-12 seconds.

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