3D Random Magnetic Pattern Digital Anti-Counterfeiting Mark and Its Preparation Method

Abstract

The present invention belongs to the technical field of anti-counterfeiting labels, and discloses a 3D random magnetic pattern digital anti-counterfeiting label and a preparation method thereof. The 3D random magnetic pattern digital anti-counterfeiting label includes a 3D magnetic ink anti-counterfeiting layer, and the 3D magnetic ink anti-counterfeiting layer contains 3D magnetic photovariable nanoparticles. The 3D magnetic photovariable nanoparticles include a first nano zinc oxide film layer, a first nano titanium dioxide film layer, a magnetic nano film layer, a second nano titanium dioxide film layer, and a second nano zinc oxide film layer from bottom to top. The 3D random magnetic pattern digital anti-counterfeiting label of the present invention presents obvious bright stripes at different irradiation light angles. By rotating the label to observe the dynamic photovariable effect of the 3D magnetic ink anti-counterfeiting layer from different angles for discrimination, regular particle patterns will also appear at the bright stripes, with high recognition and easy identification.

Description

Technical Field

[0001] The present invention belongs to the technical field of anti-counterfeiting labels, and particularly relates to a 3D random magnetic stripe digital anti-counterfeiting label and a preparation method thereof. Background Art

[0002] At present, magnetic induction labels are widely used in the anti-counterfeiting field. Some anti-counterfeiting labels use magnetic recording information to achieve writing and reading anti-counterfeiting. There are also some magnetic induction labels that achieve the angle-dependent optical variable effect through fixed magnetization. However, the current magnetic induction labels use methods such as magnetron sputtering, chemical vapor deposition, or evaporation to form a magnetic optical variable thin film. After the magnetic optical variable thin film is crushed and added to ordinary ink, it is printed and magnetized to form a magnetic induction label, thereby achieving the angle-dependent optical variable effect. However, due to various scratches on the surface of the magnetic optical variable thin film during the crushing and shearing process, the inconsistency of the film surface affects the consistency of light refraction, absorption, and diffraction, resulting in the problem that the bright stripes on the surface of the anti-counterfeiting label are not obvious and chaotic at different light angles, with low recognition rate and being difficult to identify.

[0003] Therefore, there is an urgent need for an anti-counterfeiting label that is convenient for consumers to distinguish the authenticity and is easy to identify. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. For this purpose, the present invention provides a 3D random magnetic stripe digital anti-counterfeiting label and a preparation method thereof. The 3D random magnetic stripe digital anti-counterfeiting label presents obvious bright stripes at different illumination light angles, and regular granular patterns also appear at the bright stripe positions, with high recognition rate and being easy to identify.

[0005] In the first aspect of the present invention, a 3D random magnetic stripe digital anti-counterfeiting label is provided. The 3D random magnetic stripe digital anti-counterfeiting label includes a 3D magnetic ink anti-counterfeiting layer, and the 3D magnetic ink anti-counterfeiting layer contains 3D magnetic optical variable nanoparticles. The 3D magnetic optical variable nanoparticles include a first zinc oxide nanolayer, a first titanium dioxide nanolayer, a magnetic nanolayer, a second titanium dioxide nanolayer, and a second zinc oxide nanolayer from bottom to top.

[0006] Preferably, the 3D magnetic optical variable nanoparticles are circular sheet-like particles, and the diameter of the 3D magnetic optical variable nanoparticles is 450 - 500 nm, and the thickness is 100 - 160 nm.

[0007] Preferably, the thickness of the first zinc oxide nanolayer is 20 - 25 nm, the thickness of the first titanium dioxide nanolayer is 15 - 30 nm, the thickness of the magnetic nanolayer is 30 - 50 nm, the thickness of the second titanium dioxide nanolayer is 15 - 30 nm, and the thickness of the second zinc oxide nanolayer is 20 - 25 nm.

[0008] Preferably, the addition amount of the 3D magnetic optically variable nanoparticles in the 3D magnetic ink anti-counterfeiting layer is 15-25 wt%.

[0009] Preferably, the 3D random magnetic pattern digital anti-counterfeiting label further includes a release film layer, an adhesive layer, a PET plastic film layer, a printing layer, a scratch-resistant protective layer, and an anti-counterfeiting verification code shielding layer; the release film layer and the adhesive layer are provided on the bottom surface of the PET plastic film layer, and the 3D magnetic ink anti-counterfeiting layer, the printing layer, the scratch-resistant protective layer, and the anti-counterfeiting verification code shielding layer are provided on the surface of the PET plastic film layer.

[0010] Preferably, the 3D magnetic ink anti-counterfeiting layer includes an anti-counterfeiting magnetic stripe area and an anti-counterfeiting two-dimensional code area, and the printing layer includes a LOGO area and an anti-counterfeiting verification code area; the 3D magnetic ink anti-counterfeiting layer is provided on the surface of the PET plastic film layer, the LOGO area of the printing layer is provided on the surface of the PET plastic film layer, the anti-counterfeiting verification code area of the printing layer is provided on the surface of the 3D magnetic ink anti-counterfeiting layer, the scratch-resistant protective layer is provided on the surfaces of the PET plastic film layer, the 3D magnetic ink anti-counterfeiting layer, and the printing layer, and the anti-counterfeiting verification code shielding layer is provided on the surface of the scratch-resistant protective layer and is located above the anti-counterfeiting verification code area of the printing layer.

[0011] Preferably, the 3D magnetic ink anti-counterfeiting layer includes an anti-counterfeiting magnetic stripe area and an anti-counterfeiting two-dimensional code area for writing and reading product information; the anti-counterfeiting magnetic stripe area is located at the bottom end of the 3D random magnetic pattern digital anti-counterfeiting label, facilitating the writing and reading of information by a magnetic card reader / writer.

[0012] The second aspect of the present invention provides a preparation method of the above 3D random magnetic pattern digital anti-counterfeiting label, including the following steps:

[0013] Screen-print the 3D magnetic anti-counterfeiting ink on the surface of the PET plastic film layer, and then perform magnetic fixation and UV curing to form a 3D magnetic ink anti-counterfeiting layer having an anti-counterfeiting magnetic stripe area and an anti-counterfeiting two-dimensional code area; the 3D magnetic anti-counterfeiting ink contains the 3D magnetic optically variable nanoparticles;

[0014] Perform inkjet printing on the surfaces of the PET plastic film layer and the 3D magnetic ink anti-counterfeiting layer to form a printing layer having a LOGO area and an anti-counterfeiting verification code area;

[0015] Coat the UV varnish on the surfaces of the PET plastic film layer, the 3D magnetic ink anti-counterfeiting layer, and the printing layer to form a scratch-resistant protective layer;

[0016] Screen-print the scratch-off ink on the surface of the scratch-resistant protective layer to form an anti-counterfeiting verification code shielding layer;

[0017] Write product information in the anti-counterfeiting magnetic stripe area of the 3D magnetic ink anti-counterfeiting layer;

[0018] An adhesive is coated on the bottom surface of the PET plastic film layer to form an adhesive layer, and then a release film layer is covered on the bottom surface of the adhesive layer. The 3D random magnetic pattern digital anti-counterfeiting mark is obtained by die-cutting.

[0019] Preferably, no adhesive is applied to the bottom of the anti-counterfeiting magnetic stripe area, and die-cutting is performed on the left and right sides and the bottom of the anti-counterfeiting magnetic stripe area to facilitate the removal of the anti-counterfeiting magnetic stripe area when data needs to be read from the magnetic card. When the anti-counterfeiting magnetic stripe area is removed, it cannot be restored to its original appearance, which can effectively prevent the falsification of the logo.

[0020] Preferably, the release film layer is made of PET, PE or OPP, and has a thickness of 0.05-0.15 mm.

[0021] Preferably, the coating amount of the adhesive is 20-26 g / m 2 .

[0022] Preferably, the thickness of the PET plastic film layer is 0.2-0.5 mm.

[0023] Preferably, the anti-counterfeiting magnetic stripe area and the anti-counterfeiting QR code area are screen-printed using a screen printing machine, the scraping hardness is 75-85 degrees Shore hardness, the scraping angle is 27-33 degrees, the mesh spacing is 1.5-2.0mm, the screen printing speed is 130-150mm / min, and UV lamp curing is used.

[0024] Preferably, the UV varnish coating is applied by a 300-500 mesh anilox roller.

[0025] Preferably, the 3D magnetic anti-counterfeiting ink further contains at least one of a colorant, a linker, a photoinitiator and an auxiliary agent.

[0026] Preferably, the colorant is added to the 3D magnetic anti-counterfeiting ink in an amount of 10-20 wt %. The colorant includes at least one of a direct dye, a reactive dye, and a pigment. The colorant includes but is not limited to benzidine yellow G and sun-fast red.

[0027] Preferably, the amount of the binder added to the 3D magnetic anti-counterfeiting ink is 50-65 wt %.The binder is a mixture of epoxy acrylate and dipropylene glycol diacrylate in a mass ratio of 1:(0.85-0.95).

[0028] Preferably, the addition amount of the photoinitiator in the 3D magnetic anti-counterfeiting ink is 2-5 wt%. The photoinitiator includes at least one of 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl phenyl ketone, 2-isopropyl thioxanthone, 2-hydroxy-4-n-octyloxybenzophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide.

[0029] Preferably, the addition amount of the additive in the 3D magnetic anti-counterfeiting ink is 1-6 wt%. The additive includes at least one of a defoamer, a dispersant, and a leveling agent.

[0030] Preferably, the preparation method of the 3D magnetic anti-counterfeiting ink includes the steps of: mixing the 3D magnetic photochromic nanoparticles with a colorant, a binder, a photoinitiator, and an additive, and stirring evenly to obtain the 3D magnetic anti-counterfeiting ink.

[0031] Preferably, the 3D magnetic photochromic nanoparticles are prepared by the AAO template method.

[0032] Preferably, the specific preparation process of the AAO template method is as follows:

[0033] (1) Prepare a double-pass AAO template, and compound the double-pass AAO template with a silicon wafer to obtain an AAO / Si composite template;

[0034] (2) Prepare an electrolyte containing zinc. Using the AAO / Si composite template as the cathode and graphite as the anode, carry out electrochemical deposition to obtain an AAO / Si composite template deposited with the first nano-zinc oxide film layer, which is used as composite template A;

[0035] (3) Prepare an electrolyte containing titanium. Using composite template A as the cathode, platinum as the anode, and silver / silver chloride as the reference electrode, carry out electrochemical deposition to further deposit the first nano-titanium dioxide film layer on the surface of the first nano-zinc oxide film layer to obtain composite template B;

[0036] (4) Prepare an electrodeposition solution containing nickel, iron, and gallium. Using composite template B as the cathode and graphite as the anode, adopt a two-electrode system to carry out electrochemical deposition to further deposit the magnetic nano-film layer on the surface of the first nano-titanium dioxide film layer to obtain composite template C;

[0037] (5) Prepare an electrolyte containing titanium. Using composite template C as the cathode, platinum as the anode, and silver / silver chloride as the reference electrode, carry out electrochemical deposition to further deposit the second nano-titanium dioxide film layer on the surface of the magnetic nano-film layer to obtain composite template D;

[0038] (6) preparing a zinc-containing electrolyte, using the composite template D as a cathode and graphite as an anode, performing electrochemical deposition, further depositing the second zinc oxide film layer on the surface of the second nano-titanium dioxide film layer, and then removing the AAO / Si composite template to obtain the 3D magnetic optically variable nanoparticles.

[0039] Preferably, in the specific preparation process of the AAO template method, the specific process of step (1) is:

[0040] (1.1) Aluminum foil pretreatment:

[0041] ①Cutting and flattening:

[0042] Before use, aluminum foil with a thickness of 800-900 nm was cut into discs with a diameter of 20 mm to adapt to the diameter of the electrolytic cell used during oxidation. In order to reduce the uneven stress distribution caused by uneven cutting, a tablet press was used for flattening, and the pressure was controlled at 1.3-2 MPa.

[0043] ② Annealing:

[0044] The flattened aluminum foil is annealed in a vacuum tube furnace protected by an argon atmosphere at 400-500°C for 3-5 hours. After annealing, it is cooled to room temperature in the furnace. Unheat-treated aluminum foil has strong internal stress, which is not conducive to the formation of highly ordered nanopores. In order to eliminate the residual stress in the aluminum foil as much as possible, increase the crystallinity, and improve the order of the AAO template, high-temperature annealing is used to further improve the performance of the alumina template. The hardness of the aluminum foil after annealing pretreatment is reduced, making it more convenient for subsequent processing.

[0045] ③Cleaning:

[0046] In order to ensure the quality of the prepared nanoarray, the quality of the alumina template needs to be guaranteed, so it must be rinsed clean. The heat-treated aluminum foil is ultrasonically cleaned one by one using acetone, anhydrous ethanol and deionized water. Each cleaning time is set to 10 minutes to remove the grease on the surface; after cleaning and drying, it is immersed in 10% sodium hydroxide solution for 10-15 minutes to remove the original natural oxide layer, and then rinsed with clean water for 20-30 minutes until the residual sodium hydroxide on the surface of the aluminum foil is rinsed clean to prevent pitting during electrochemical polishing and breakdown during oxidation; finally, blow dry and place in a culture dish for later use;

[0047] ④Polishing:

[0048] A solution prepared by mixing absolute ethanol and perchloric acid in a volume ratio of 4:1 is used as the polishing solution. Aluminum foil is used as the anode and graphite as the cathode, and polishing is carried out at a voltage of 15 - 20V for 2 - 5 minutes; subsequently, it is washed with deionized water to remove the polishing solution and dried with nitrogen. The purpose of polishing is to remove the oxide layer on the surface of the aluminum foil, improve the surface brightness, remove surface protrusions or pits, prevent defects on the aluminum foil surface from affecting the growth of nanopores, and prevent the texture of the aluminum foil itself from affecting the formation of the alumina film. If the voltage is too high during the polishing process, the current will increase, resulting in an increase in the solution temperature and the surface of the aluminum foil being easily burned; if the voltage is too low, the polishing time will be extended and the production efficiency will be low.

[0049] (1.2) Anodic oxidation (primary oxidation and secondary oxidation)

[0050] ① Primary anodic oxidation:

[0051] Using aluminum foil as the anode and graphite as the cathode, controlling the distance between the two electrodes to be 60 - 70 mm, using 0.3 mol / L oxalic acid solution as the electrolyte, oxidizing at a voltage of 35 - 45V for 5 - 8 hours, and during the oxidation process, controlling the temperature at 5 - 10°C;

[0052] ② Secondary anodic oxidation:

[0053] The corroded sample is cleaned and dried. Carry out the second anodic oxidation, and the oxidation conditions are the same as the first oxidation. The difference is that at the end of the reaction, the voltage is gradually decreased from the highest point to 0V at a rate of 1V / s. The purpose of this is to thin the barrier layer at the bottom of the AAO to facilitate subsequent removal;

[0054] (3) Bottom removal and pore expansion:

[0055] Bottom removal: There is an aluminum substrate under the oxide film produced by secondary oxidation. To obtain a complete AAO film, it is necessary to carry out the removal treatment of the bottom. 0.1 g / mL of CuCl2 is used as the stripping solution, and the reaction of the aluminum substrate with the CuCl2 solution for bottom removal is as follows:

[0056] 2Al + 3CuCl2 = 2AlCl3 + 3Cu;

[0057] After the reaction is complete, the AAO template is slowly taken out and placed in deionized water for cleaning to remove the reaction products;

[0058] Removing the barrier layer and pore expansion: The AAO film separated from the aluminum substrate is placed in a mixed solution of 0.5 wt% phosphoric acid and 0.3 mol / L oxalic acid, controlling the solution temperature at 25 - 30°C, and expanding the pores for 200 - 250 minutes to remove the barrier layer. At this time, due to capillary action, the solution penetrates into the pores and corrodes the pore walls to achieve pore expansion, and a double-pass AAO template is prepared with a pore diameter of 450 - 500 nm and a pore spacing of 150 - 200 nm;

[0059] (1.3) Preparation of AAO / Si Composite Template

[0060] The prepared double-pass AAO template was cleaned, dried, and then immersed in absolute ethanol. Subsequently, it was placed on a silicon wafer with a pre-deposited metal conductive layer, and immediately pressed with a quartz slide to prevent it from falling off after drying, thus obtaining the AAO / Si composite template;

[0061] Preferably, in the specific preparation process of the AAO template method, the specific process of step (2) is as follows:

[0062] (2.1) Preparation of zinc-containing electrolyte: Zinc oxide was added to 3 mol / L NaOH solution, stirred until the solution was clear, cooled to room temperature, and the obtained electrolyte was reserved for use. Each 100 g of H2O in the electrolyte contained 1 g of ZnO;

[0063] (2.2) Using the AAO / Si composite template as the cathode and graphite (40x60 mm) as the anode, electrochemical deposition was carried out by the equal-current method. The anode and cathode were respectively placed about 2 cm away from the cell wall, with a spacing of 6 - 8 cm, and the current was controlled at 2.5 A / dm 2 , and the electro-deposition was carried out for 0.3 - 0.5 h. Then, the ZnO on the surface of the AAO / Si composite template was cleaned with nitric acid solution and dried at 80 °C to obtain the AAO / Si composite template deposited with the first nano-zinc oxide film layer, which was used as composite template A.

[0064] Preferably, in the specific preparation process of the AAO template method, the specific process of step (3) is as follows:

[0065] (3.1) Preparation of titanium-containing electrolyte: 1 L of deionized water was poured into a beaker with a magnetic stirrer, and then 5 g of TiF4 and 5 g of NiCl2·6H20 were put into the beaker and continuously stirred at room temperature for 30 minutes to obtain the electrolyte for use. The electrolyte contained 0.04 M TiF4 and 0.02 M NiCl2;

[0066] (3.2) Insert the Pt electrode (anode) and the reference electrode Ag / AgCl electrode. The composite template A was glued to a thin copper wire with silver paste as the cathode, and after inserting the template into the electrolyte, it was soaked for about 10 minutes to allow the electrolyte to enter the template pores. The deposition potential was controlled at -0.8 to -0.4 V, and the electro-deposition was carried out for 0.3 - 1.2 h. After the deposition was completed, the template was taken out and repeatedly rinsed with deionized water, and then soaked in deionized water for 30 minutes to completely remove the electrolyte, and dried at 80 °C. The first nano-titanium dioxide film layer was further deposited on the surface of the first nano-zinc oxide film layer to obtain composite template B.

[0067] Preferably, in the specific preparation process of the AAO template method, the specific process of step (4) is as follows:

[0068] (4.1) Prepare an electrodeposition solution containing nickel, iron, and gallium: Use 0.017 M (mol / L) of NiSO4·6H2O, 0.0075 M of FeSO4·7H2O, and 0.12 M of Ga2(SO4)3·18H2O as the main electrodeposition salts; 0.2 M of sodium citrate (C6H5Na3O7·2H2O) and 0.3 M of ammonium sulfate as complexing agents. At the same time, ammonium sulfate also serves as the conductive salt of the electrodeposition solution, 0.5 M of boric acid as the pH buffer, 0.02 M of ascorbic acid as the antioxidant, 0.03 g / L of sodium dodecyl sulfate as the wetting agent. Finally, adjust the pH of the electrodeposition solution to 2.5 - 3 with NaOH and H2SO4. The volume of the electrodeposition solution is 50 or 100 mL.

[0069] (4.2) Using the composite template B as the cathode and graphite as the anode, carry out electrochemical deposition under a constant voltage at room temperature using a two - electrode system. Control the deposition voltage at 2.5 V and electrodeposit for 1.2 - 2.5 h. Then, clean the electrodeposition solution on the template surface with NaOH solution, dry it at 80 °C, and further deposit the magnetic nanolayer on the surface of the first nano - titanium dioxide film layer to obtain composite template C.

[0070] Preferably, in the specific preparation process of the AAO template method, the specific process of step (5) is as follows:

[0071] (5.1) Prepare an electrolyte containing titanium: Pour 1 L of deionized water into a beaker with a magnetic stirrer, then put 5 g of TiF4 and 5 g of NiCl2·6H20 into the beaker, and continuously stir at room temperature for 30 minutes to obtain the standby electrolyte. The electrolyte contains 0.04 M TiF4 and 0.02 M NiCl2.

[0072] (5.2) Insert a Pt electrode (anode) and a reference electrode Ag / AgCl electrode. Glue the composite template C to a fine copper wire as the cathode with silver glue. After inserting the template into the electrolyte, soak it for about 10 minutes to allow the electrolyte to enter the template pores. Control the deposition potential at - 0.8 to - 0.4 V and electrodeposit for 0.3 - 1.2 h. After the deposition is completed, take out the template and rinse it repeatedly with deionized water, then soak it in deionized water for 30 minutes to completely remove the electrolyte, dry it at 80 °C, and further deposit the second nano - titanium dioxide film layer on the surface of the magnetic nanolayer to obtain composite template D.

[0073] Preferably, in the specific preparation process of the AAO template method, the specific process of step (6) is as follows:

[0074] (6.1) Preparation of zinc-containing electrolyte: Zinc oxide is added to 3 mol / L NaOH solution, stirred until the solution is clear, cooled to room temperature, and the electrolyte is obtained for standby. Each 100 g of H2O in the electrolyte contains 1 g of ZnO;

[0075] (6.2) Using the composite template D as the cathode and graphite as the anode, electrochemical deposition is carried out by the equal current method. The anode and cathode are respectively placed about 2 cm away from the cell wall, with a spacing of 6 - 8 cm, and the current is controlled at 2.5 A / dm 2 , electro-deposit for 0.3 - 0.5 h, then clean the ZnO on the template surface with nitric acid solution, dry it at 80 °C, and further deposit the second zinc oxide film layer on the surface of the second titanium dioxide film layer;

[0076] (6.3) Slowly stick 3M470 electroplating tape on the surface of the AAO / Si composite template. The nano-hole array of the AAO / Si composite template is loaded with 3D magnetic optical variable nanoparticles formed by the first zinc oxide nano-film layer, the first titanium dioxide nano-film layer, the magnetic nano-film layer, the second titanium dioxide nano-film layer, and the second zinc oxide nano-film layer. Press with the finger pulp to make the tape and the AAO / Si composite template in full contact, and then slowly tear off the tape. The AAO template is torn off and stuck on the tape, and the remaining 3D magnetic optical variable nanoparticles are evenly arranged on the silicon wafer. Take down the 3D magnetic optical variable nanoparticles to obtain the 3D magnetic optical variable nanoparticles.

[0077] The third aspect of the present invention provides an anti-counterfeiting product, and the 3D random magnetic stripe digital anti-counterfeiting mark of the present invention is provided on the product.

[0078] When consumers identify the authenticity:

[0079] 1. Visual identification: Discriminate by observing the dynamic light-changing effect of the 3D magnetic ink anti-counterfeiting layer from different angles by rotating the mark. Bright stripes appear at different illumination light angles. At the details of the bright stripes, different from the disorder of the existing magnetic ink, the 3D magnetic ink anti-counterfeiting layer of the present invention contains 3D magnetic optical variable nanoparticles with the same particle size and thickness. Therefore, when observing the details of the bright stripes with the naked eye or a magnifying glass, regular particle patterns will also appear at the bright stripes.

[0080] 2. Two-dimensional code identification: Scratch off the anti-counterfeiting verification code shielding layer, scan the anti-counterfeiting two-dimensional code area, input the anti-counterfeiting verification code to view various information of the product, and obtain the result of feedback on the authenticity of the product and check the verification code. The verification code to be checked is a random code sent by the system. This code is used as the password for reading the information of the anti-counterfeiting magnetic stripe area, which has randomness and time limit, and can effectively avoid counterfeiting.

[0081] 3. Anti-counterfeiting magnetic stripe information reading and identification: The verification code obtained by scanning the anti-counterfeiting QR code area is used as the password and input into the magnetic card reader. Only in this way can the anti-counterfeiting magnetic stripe product information be read by the magnetic card reader. Then, the anti-counterfeiting magnetic stripe product information read by the magnetic card reader is compared with the product information obtained from the QR code scanning result. If all the information is consistent, it is a genuine product.

[0082] The 3D magnetic ink anti-counterfeiting layer of the present invention includes an anti-counterfeiting magnetic stripe area for writing various product information. In combination with the anti-counterfeiting QR code, by scanning the anti-counterfeiting QR code and inputting the anti-counterfeiting verification code to view various product information, the result of feedback on the authenticity of the product and the verification code are obtained. And the various product information obtained by scanning the QR code is compared with the information read from the anti-counterfeiting magnetic stripe to further verify the authenticity of the product and increase the difficulty of counterfeiting the label.

[0083] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0084] 1. The 3D random magnetic pattern digital anti-counterfeiting label of the present invention presents obvious bright stripes at different illumination light angles. By rotating the label to observe the dynamic light-changing effect of the 3D magnetic ink anti-counterfeiting layer from different angles for discrimination. At the details of the bright stripes, different from the disorder of the existing magnetic ink, the 3D magnetic ink anti-counterfeiting layer of the present invention contains 3D magnetic light-changing nanoparticles with the same particle size and thickness. Therefore, when observing the details of the bright stripes with the naked eye or a magnifying glass, regular particle patterns will also appear at the bright stripes, with high recognition and easy to identify.

[0085] 2. The present invention uses the AAO template method to prepare 3D magnetic light-changing nanoparticles, and realizes the uniform distribution of each material film layer in the ordered nanopores of the AAO template through electroplating. Compared with methods such as magnetron sputtering, chemical vapor deposition, and evaporation for forming magnetic thin films and functional thin films, the preparation method of the present invention is more efficient and convenient. Moreover, the prepared 3D magnetic light-changing nanoparticles have the same size and film thickness, reducing the complicated steps of still needing to break the sputtered magnetic film into nanoparticles by shear force, and avoiding the damage to the surface of the thin film by the shear force. Thus, it avoids the problem that the inconsistent surface of the thin film affects the consistency of light refraction, absorption, and diffraction, resulting in the unclear light-changing bright stripes on the surface of the label at different light angles.

[0086] 3. The 3D magnetic ink anti-counterfeiting layer prepared by the present invention using 3D magnetic anti-counterfeiting ink through magnetic fixing and curing makes the 3D magnetic light-changing nanoparticles in the ink rearrange and orient, realizing the magneto-optical effect of 3D dazzling movement and color change of the 3D magnetic ink anti-counterfeiting layer with different viewing angles, which is not easy to be counterfeited and has good anti-counterfeiting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] The following further describes the present invention in conjunction with the drawings and embodiments.

[0088] Figure 1 It is a schematic diagram of the layer structure of the 3D random magnetic pattern digital anti-counterfeiting label of the present invention;

[0089] Figure 2 It is a schematic diagram of the planar structure of the 3D random magnetic pattern digital anti-counterfeiting label of the present invention;

[0090] Figure 3 It is a schematic diagram of the structure of the 3D magnetic optically variable nanoparticles of the present invention.

[0091] In the figure: 1, release film layer; 2, adhesive layer; 3, PET plastic film layer; 4, 3D magnetic ink anti-counterfeiting layer; 41, anti-counterfeiting magnetic stripe area; 42, anti-counterfeiting QR code area; 5, printing layer; 51, LOGO area; 52, anti-counterfeiting verification code area; 6, scratch-resistant protective layer; 7, anti-counterfeiting verification code shielding layer; 81, first nano-zinc oxide film layer; 82, first nano-titanium dioxide film layer; 83, magnetic nano-film layer; 84, second nano-titanium dioxide film layer; 85, second nano-zinc oxide film layer. Specific embodiments

[0092] In order to make those skilled in the art more clearly understand the technical solutions of the present invention, the following examples are listed for illustration. It should be noted that the following examples do not limit the scope of protection required by the present invention.

[0093] The raw materials, reagents, and devices used in the following examples can be obtained from conventional commercial channels or can be obtained by existing known methods without special instructions. The room temperature in the present invention refers to 15 - 40 °C.

[0094] Example 1

[0095] This example provides a 3D random magnetic pattern digital anti-counterfeiting label.

[0096] Specifically, as Figure 1 and Figure 2As shown in the figure, the 3D random magnetic pattern digital anti-counterfeiting label includes a release film layer 1, an adhesive layer 2, a PET plastic film layer, a 3D magnetic ink anti-counterfeiting layer, a printing layer 5, a scratch-resistant protective layer 6, and an anti-counterfeiting verification code shielding layer 7; the 3D magnetic ink anti-counterfeiting layer includes an anti-counterfeiting magnetic stripe area 41 and an anti-counterfeiting QR code area 42 for writing and reading product information, and the printing layer 5 includes a LOGO area and an anti-counterfeiting verification code area 52; the release film layer 1 and the adhesive layer 2 are provided on the bottom surface of the PET plastic film layer, the 3D magnetic ink anti-counterfeiting layer is provided on the surface of the PET plastic film layer, the LOGO area of the printing layer 5 is provided on the surface of the PET plastic film layer, and the LOGO area is directly above the anti-counterfeiting QR code area 42. The anti-counterfeiting verification code area 52 of the printing layer 5 is provided on the surface of the 3D magnetic ink anti-counterfeiting layer, and the anti-counterfeiting verification code area 52 is located at the bottom surface of the anti-counterfeiting QR code area 42. The scratch-resistant protective layer 6 is provided on the surfaces of the PET plastic film layer, the 3D magnetic ink anti-counterfeiting layer, and the printing layer 5. The anti-counterfeiting verification code shielding layer 7 is provided on the surface of the scratch-resistant protective layer 6, and the anti-counterfeiting verification code shielding layer 7 is located above the anti-counterfeiting verification code area 52 of the printing layer 5 to shield the anti-counterfeiting verification code.

[0097] The preparation method of the 3D random magnetic pattern digital anti-counterfeiting label in this embodiment includes the following steps:

[0098] (1) Print 3D magnetic anti-counterfeiting ink on the surface of a PET plastic film layer with a thickness of 0.2 mm, then use a magnet for magnetization and cure with a UV lamp to form a 3D magnetic ink anti-counterfeiting layer with an anti-counterfeiting magnetic stripe area and an anti-counterfeiting QR code area; among them, the anti-counterfeiting magnetic stripe area and the anti-counterfeiting QR code area are screen-printed using a screen printing machine, the scraping rubber hardness is 75-85 degrees of Shore hardness, the scraping rubber angle is 27-33 degrees, the screen distance is 1.5-2.0 mm, and the screen printing speed is 130-150 mm / min;

[0099] (2) On the surface of the PET plastic film layer and directly above the anti-counterfeiting QR code area, spray-print the LOGO area, and on the bottom surface of the anti-counterfeiting QR code area of the 3D magnetic ink anti-counterfeiting layer, spray-print the anti-counterfeiting verification code area to form a printing layer with a LOGO area and an anti-counterfeiting verification code area;

[0100] (3) Coat the UV varnish on the surfaces of the PET plastic film layer, the 3D magnetic ink anti-counterfeiting layer, and the printing layer using a 320-mesh anilox roll, and cure with a UV lamp to form a scratch-resistant protective layer; the UV varnish is UV-503 produced by Dongguan Yilian Chemical Technology Co., Ltd.;

[0101] (4) Screen-print the scratch-off ink on the surface of the scratch-resistant protective layer, and after hot air drying, form an anti-counterfeiting verification code shielding layer, and the anti-counterfeiting verification code shielding layer is located above the anti-counterfeiting verification code area; the scratch-off ink is the LD-S50866 series of water-based scratch-off inks produced by Guangzhou Ledi New Material Technology Co., Ltd.;

[0102] (5) Write various commodity information into the anti-counterfeiting magnetic stripe area through the 3D magnetic ink anti-counterfeiting layer;

[0103] (6) Coat an adhesive on the bottom surface of the PET plastic film layer, with a coating amount of 20 g / m 2 , form an adhesive layer, then cover a PET release film layer with a thickness of 0.05 mm on the bottom surface of the adhesive layer, and then perform die-cutting on the left and right sides and the lower part of the anti-counterfeiting magnetic stripe area on the surface of the PET plastic film layer to obtain a 3D random magnetic pattern digital anti-counterfeiting label.

[0104] The 3D magnetic anti-counterfeiting ink used in this embodiment contains 3D magnetic photovariable nanoparticles. As Figure 3 shown, the 3D magnetic photovariable nanoparticles include a first nano-zinc oxide film layer 81, a first nano-titanium dioxide film layer 82, a magnetic nano-film layer 83, a second nano-titanium dioxide film layer 84, and a second nano-zinc oxide film layer 85 from bottom to top.

[0105] The preparation method of the 3D magnetic photovariable nanoparticles in this embodiment includes the following steps:

[0106] Step 1: Preparation of a double-pass AAO template

[0107] (1) Aluminum foil pretreatment

[0108] ① Cutting and flattening

[0109] Before use, cut an aluminum foil with a thickness of 800 nm into circular pieces with a diameter of 20 mm, and then use a tablet press to flatten it, with the pressure controlled at 1.3 MPa.

[0110] ② Annealing

[0111] Anneal the flattened aluminum foil in a vacuum tube furnace with an argon atmosphere protection at 400 - 500 °C, set the annealing time to 3 h, and cool it to room temperature with the furnace after annealing.

[0112] ③ Cleaning

[0113] The annealed aluminum foil is ultrasonically cleaned one by one with acetone, absolute ethanol, and deionized water, with each cleaning time set to 10 min to remove the surface grease; after cleaning and drying, soak it in a 10% sodium hydroxide solution for 10 min to remove the original natural oxide layer, and then continuously rinse it with water for 20 min until the sodium hydroxide residue on the surface of the aluminum foil is rinsed clean, and dry it and put it in a petri dish for standby.

[0114] ④ Polishing

[0115] A solution prepared from anhydrous ethanol and perchloric acid in a volume ratio of 4:1 was used as the polishing solution. After cleaning, the aluminum foil was used as the anode, graphite as the cathode, and polished at a voltage of 15V for 2 minutes; subsequently, it was washed with deionized water to remove the polishing solution and dried with nitrogen.

[0116] (2) Secondary anodic oxidation

[0117] ① First anodic oxidation

[0118] Using the pretreated aluminum foil as the anode and graphite as the cathode, controlling the distance between the two electrodes to be 60mm, using 0.3mol / L oxalic acid solution as the electrolyte, oxidizing at a voltage of 35V for 5 hours, and during the oxidation process, the temperature was controlled at 5°C.

[0119] ② Second anodic oxidation

[0120] The aluminum foil subjected to the first anodic oxidation was cleaned and dried, and then subjected to the second anodic oxidation. The oxidation conditions were the same as those of the first oxidation; the difference was that at the end of the second anodic oxidation reaction, the voltage was gradually decreased from the highest point to 0V using the step-down method, and the voltage reduction rate was 1V / s.

[0121] (3) Bottom removal and pore expansion

[0122] Bottom removal: There is an aluminum substrate under the oxide film produced by secondary oxidation. Using 0.1g / mL of CuCl2 as the stripping solution, the reaction of the aluminum substrate with the CuCl2 solution for bottom removal is as follows:

[0123] 2Al + 3CuCl2 = 2AlCl3 + 3Cu;

[0124] After the reaction is complete, the template is slowly taken out and placed in deionized water for cleaning to remove the reaction products.

[0125] Removing the barrier layer and pore expansion: The template detached from the aluminum substrate was placed in a mixed solution of 0.5wt% phosphoric acid and 0.3mol / L oxalic acid, the solution temperature was controlled at 25°C, and the pores were expanded for 200 minutes to remove the barrier layer, obtaining a double-pass AAO template with a pore diameter of 450nm and a pore spacing of 150nm.

[0126] (3) Preparation of AAO / Si composite template

[0127] The prepared double-pass AAO template was cleaned, dried, and then immersed in anhydrous ethanol; subsequently, it was placed on a silicon wafer with a pre-deposited metal conductive layer, and immediately pressed with a quartz cover glass to obtain an assembled AAO / Si composite template.

[0128] Step two: Preparation of the first nano-zinc oxide film layer

[0129] (1) Prepare a zinc-containing electrolyte: Add zinc oxide to 3 mol / L NaOH solution, stir until the solution is clear, and cool to room temperature to obtain the electrolyte for standby. In the electrolyte, 1 g of ZnO is contained in every 100 g of H2O;

[0130] (2) Using the AAO / Si composite template as the cathode and graphite (40x60 mm) as the anode, perform electrochemical deposition by the constant current method. The anode and cathode are respectively placed about 2 cm away from the cell wall, with a spacing of 6 cm. Control the current to be 2.5 A / dm 2 , and perform electro-deposition for 0.3 h. Then, clean the ZnO on the surface of the AAO / Si composite template with nitric acid solution, and dry it at 80 °C to obtain the AAO / Si composite template deposited with the first nano-zinc oxide film layer, which is used as composite template A.

[0131] Step 3: Preparation of the first nano-titanium dioxide film layer

[0132] (1) Prepare a titanium-containing electrolyte: Pour 1 L of deionized water into a beaker with a magnetic stirrer, then put 5 g of TiF4 and 5 g of NiCl2·6H2O into the beaker, and continuously stir at room temperature for 30 minutes to obtain the electrolyte for standby. The electrolyte contains 0.04 M TiF4 and 0.02 M NiCl2;

[0133] (2) Insert a Pt electrode (anode) and a reference electrode Ag / AgCl electrode. Glue the composite template A to a fine copper wire with silver glue as the cathode. After inserting the template into the electrolyte, soak it for about 10 minutes to allow the electrolyte to enter the pores of the template. Control the deposition potential to be -0.8 V, and perform electro-deposition for 0.3 h. After the deposition is completed, take out the template and rinse it repeatedly with deionized water, then soak it in deionized water for 30 minutes to completely remove the electrolyte, and dry it at 80 °C to further deposit the first nano-titanium dioxide film layer on the surface of the first nano-zinc oxide film layer to obtain composite template B.

[0134] Step 4: Preparation of the magnetic nano-film layer

[0135] (1) Prepare an electro-deposition solution containing nickel, iron, and gallium: Use 0.017 M (mol / L) of NiSO4·6H2O, 0.0075 M of FeSO4·7H2O, and 0.12 M of Ga2(SO4)3·18H2O as the main electro-deposition salts; 0.2 M of sodium citrate (C6H5Na3O7·2H2O) and 0.3 M of ammonium sulfate as complexing agents. At the same time, ammonium sulfate also serves as the conductive salt of the electro-deposition solution, 0.5 M of boric acid as a pH buffer, 0.02 M of ascorbic acid as an antioxidant, and 0.03 g / L of sodium dodecyl sulfate as a wetting agent. Finally, adjust the pH of the electro-deposition solution to 2.5 with NaOH and H2SO4. The volume of the electro-deposition solution is 50 mL;

[0136] (2) Using composite template B as the cathode and graphite as the anode, electrochemical deposition is carried out in a two-electrode system at a constant voltage at room temperature. The deposition voltage is controlled at 2.5 V, and the electro-deposition is carried out for 1.2 h. Then, the electro-deposition solution on the surface of the template is cleaned with NaOH solution and dried at 80 °C. A magnetic nano-film layer is further deposited on the surface of the first nano-titanium dioxide film layer to obtain composite template C.

[0137] Step Five: Preparation of the second nano-titanium dioxide film layer

[0138] (1) Prepare a titanium-containing electrolyte: Pour 1 L of deionized water into a beaker with a magnetic stirrer, then put 5 g of TiF4 and 5 g of NiCl2·6H2O into the beaker and continuously stir for 30 minutes at room temperature to obtain the electrolyte for standby. The electrolyte contains 0.04 M TiF4 and 0.02 M NiCl2;

[0139] (2) Insert a Pt electrode (anode) and a reference electrode Ag / AgCl electrode. Glue composite template C to a fine copper wire with silver glue as the cathode, and after inserting the template into the electrolyte, soak it for about 10 minutes to allow the electrolyte to enter the pores of the template. Control the deposition potential at -0.8 V and carry out electro-deposition for 0.3 h. After the deposition is completed, take out the template and rinse it repeatedly with deionized water, then soak it in deionized water for 30 minutes to completely remove the electrolyte, and dry it at 80 °C. A second nano-titanium dioxide film layer is further deposited on the surface of the magnetic nano-film layer to obtain composite template D.

[0140] Step Six: Preparation of the second nano-zinc oxide film layer

[0141] (1) Prepare a zinc-containing electrolyte: Add zinc oxide to 3 mol / L NaOH solution, stir until the solution is clear, and cool to room temperature to obtain the electrolyte for standby. The electrolyte contains 1 g of ZnO per 100 g of H2O;

[0142] (2) Using composite template D as the cathode and graphite as the anode, electrochemical deposition is carried out by the equal current method. The anode and cathode are respectively placed about 2 cm away from the cell wall, with a spacing of 6 cm. Control the current at 2.5 A / dm 2 , and carry out electro-deposition for 0.3 h. Then, clean the ZnO on the surface of the template with nitric acid solution and dry it at 80 °C. A second zinc oxide film layer is further deposited on the surface of the second nano-titanium dioxide film layer.

[0143] Step 7: Slowly stick the 3M470 electroplating tape on the surface of the AAO / Si composite template. The nano-hole array of the AAO / Si composite template is loaded with 3D magnetic optically variable nanoparticles formed by a first nano-zinc oxide film layer, a first nano-titanium dioxide film layer, a magnetic nano-film layer, a second nano-titanium dioxide film layer, and a second nano-zinc oxide film layer. Press with your finger pulp to make the tape and the AAO / Si composite template in full contact, and then slowly tear off the tape. The AAO template is torn off and stuck on the tape, and the remaining 3D magnetic optically variable nanoparticles are evenly arranged on the silicon wafer. Remove the 3D magnetic optically variable nanoparticles to obtain 3D magnetic optically variable nanoparticles.

[0144] The preparation method of the 3D magnetic anti-counterfeiting ink in this embodiment includes the following steps:

[0145] Weigh the raw materials according to mass percentages: 18% of 3D magnetic optically variable nanoparticles, 12% of colorant, 51% of binder, 4% of photoinitiator, and 5% of additives; among them, the binder is a mixture of epoxy acrylate and dipropylene glycol diacrylate with a mass ratio of 1:0.85, the additives are a mixture of defoamer, dispersant, and leveling agent, the photoinitiator is 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, and the colorant is benzidine yellow G;

[0146] Uniformly mix the above-mentioned weighed raw materials to obtain 3D magnetic anti-counterfeiting ink.

[0147] Example 2

[0148] This embodiment provides a 3D random magnetic pattern digital anti-counterfeiting label.

[0149] Specifically, as Figure 1 and Figure 2As shown in the figure, the 3D random magnetic pattern digital anti-counterfeiting label includes a release film layer 1, an adhesive layer 2, a PET plastic film layer, a 3D magnetic ink anti-counterfeiting layer, a printing layer 5, a scratch-resistant protective layer 6, and an anti-counterfeiting verification code shielding layer 7; the 3D magnetic ink anti-counterfeiting layer includes an anti-counterfeiting magnetic stripe area 41 and an anti-counterfeiting QR code area 42 for writing and reading product information, and the printing layer 5 includes a LOGO area and an anti-counterfeiting verification code area 52; the release film layer 1 and the adhesive layer 2 are arranged on the bottom surface of the PET plastic film layer, the 3D magnetic ink anti-counterfeiting layer is arranged on the surface of the PET plastic film layer, the LOGO area of the printing layer 5 is arranged on the surface of the PET plastic film layer, and the LOGO area is directly above the anti-counterfeiting QR code area 42. The anti-counterfeiting verification code area 52 of the printing layer 5 is arranged on the surface of the 3D magnetic ink anti-counterfeiting layer, and the anti-counterfeiting verification code area 52 is located at the bottom surface of the anti-counterfeiting QR code area 42. The scratch-resistant protective layer 6 is arranged on the surfaces of the PET plastic film layer, the 3D magnetic ink anti-counterfeiting layer, and the printing layer 5. The anti-counterfeiting verification code shielding layer 7 is arranged on the surface of the scratch-resistant protective layer 6, and the anti-counterfeiting verification code shielding layer 7 is located above the anti-counterfeiting verification code area 52 of the printing layer 5 to shield the anti-counterfeiting verification code.

[0150] The preparation method of the 3D random magnetic pattern digital anti-counterfeiting label in this embodiment includes the following steps:

[0151] (1) Print 3D magnetic anti-counterfeiting ink on the surface of a PET plastic film layer with a thickness of 0.5 mm, then use a magnet for magnetization and cure with a UV lamp to form a 3D magnetic ink anti-counterfeiting layer with an anti-counterfeiting magnetic stripe area and an anti-counterfeiting QR code area; among them, the anti-counterfeiting magnetic stripe area and the anti-counterfeiting QR code area are screen-printed using a screen printing machine, the scraping rubber hardness is 75-85 degrees of Shore hardness, the scraping rubber angle is 27-33 degrees, the screen distance is 1.5-2.0 mm, and the screen printing speed is 130-150 mm / min;

[0152] (2) On the surface of the PET plastic film layer and directly above the anti-counterfeiting QR code area, spray and print the LOGO area, and on the bottom surface of the anti-counterfeiting QR code area of the 3D magnetic ink anti-counterfeiting layer, spray and print the anti-counterfeiting verification code area to form a printing layer with a LOGO area and an anti-counterfeiting verification code area;

[0153] (3) Coat the UV varnish on the surfaces of the PET plastic film layer, the 3D magnetic ink anti-counterfeiting layer, and the printing layer using a 320-mesh anilox roller, and cure with a UV lamp to form a scratch-resistant protective layer; the UV varnish is UV-503 produced by Dongguan Yilian Chemical Technology Co., Ltd.;

[0154] (4) Screen-print the scratch-off ink on the surface of the scratch-resistant protective layer, and form an anti-counterfeiting verification code shielding layer after hot air drying. The anti-counterfeiting verification code shielding layer is located above the anti-counterfeiting verification code area; the scratch-off ink is the SO74 series screen-printing scratch-off ink of Dongguan Kaiyue Environmental Protection Technology Co., Ltd.;

[0155] (5) Write various product information into the anti-counterfeiting magnetic stripe area through the 3D magnetic ink anti-counterfeiting layer;

[0156] (6) Coat an adhesive on the bottom surface of the PET plastic film layer, with a coating amount of 26 g / m 2 , to form an adhesive layer, and then cover a PE release film layer with a thickness of 0.15 mm on the bottom surface of the adhesive layer. Then, after die-cutting on the left and right sides and the lower part of the anti-counterfeiting magnetic stripe area on the surface of the PET plastic film layer, a 3D random magnetic pattern digital anti-counterfeiting label is obtained.

[0157] The 3D magnetic anti-counterfeiting ink used in this embodiment contains 3D magnetic photovariable nanoparticles. As Figure 3 shown, the 3D magnetic photovariable nanoparticles include a first nano-zinc oxide film layer 81, a first nano-titanium dioxide film layer 82, a magnetic nano-film layer 83, a second nano-titanium dioxide film layer 84, and a second nano-zinc oxide film layer 85 from bottom to top.

[0158] The preparation method of the 3D magnetic photovariable nanoparticles in this embodiment includes the following steps:

[0159] Step 1: Preparation of a double-pass AAO template

[0160] (1) Aluminum foil pretreatment

[0161] ① Cutting and flattening

[0162] Before use, cut an 800-nm-thick aluminum foil into a 20-mm-diameter round piece, and then use a tablet press to flatten it, with the pressure controlled at 2 MPa.

[0163] ② Annealing

[0164] Anneal the flattened aluminum foil at 500 °C in a vacuum tube furnace with an argon atmosphere protection, set the annealing time to 5 h, and cool it to room temperature with the furnace after annealing.

[0165] ③ Cleaning

[0166] The annealed aluminum foil is ultrasonically cleaned with acetone, absolute ethanol, and deionized water one by one, with each cleaning time set to 10 min to remove the surface grease; after cleaning and drying, soak it in a 10% sodium hydroxide solution for 15 min to remove the original natural oxide layer, and then continuously rinse it with clean water for 30 min until the sodium hydroxide residue on the aluminum foil surface is rinsed clean, and dry it and put it in a petri dish for standby.

[0167] ④ Polishing

[0168] A solution prepared from anhydrous ethanol and perchloric acid in a volume ratio of 4:1 was used as the polishing solution. The cleaned aluminum foil was used as the anode, and graphite was used as the cathode. Polishing was carried out at a voltage of 20 V for 5 min; subsequently, it was washed with deionized water to remove the polishing solution and dried with nitrogen.

[0169] (2) Secondary anodic oxidation

[0170] ① First anodic oxidation

[0171] Using the pretreated aluminum foil as the anode and graphite as the cathode, controlling the distance between the two electrodes to be 70 mm, using a 0.3 mol / L oxalic acid solution as the electrolyte, oxidizing at a voltage of 45 V for 8 h. During the oxidation process, the temperature was controlled at 10 °C.

[0172] ② Second anodic oxidation

[0173] The aluminum foil that had undergone the first anodic oxidation was washed and dried, and then subjected to the second anodic oxidation. The oxidation conditions were the same as those of the first oxidation; the difference was that at the end of the second anodic oxidation, the voltage was gradually decreased from the highest point to 0 V using the stepwise voltage reduction method, and the voltage reduction rate was 1 V / s.

[0174] (3) Bottom removal and pore expansion

[0175] Bottom removal: There was an aluminum substrate under the oxide film produced by secondary oxidation. 0.1 g / mL of CuCl2 was used as the stripping solution, and the reaction for the aluminum substrate to strip with the CuCl2 solution was as follows:

[0176] 2Al + 3CuCl2 = 2AlCl3 + 3Cu;

[0177] After the reaction was complete, the template was slowly taken out and placed in deionized water for washing to remove the reaction products.

[0178] Removing the barrier layer and pore expansion: The template separated from the aluminum substrate was placed in a mixed solution of 0.5 wt% phosphoric acid and 0.3 mol / L oxalic acid. The solution temperature was controlled at 30 °C, and pore expansion was carried out for 250 min to remove the barrier layer, obtaining a double-pass AAO template with a pore diameter of 500 nm and a pore spacing of 200 nm.

[0179] (3) Preparation of AAO / Si composite template

[0180] The prepared double-pass AAO template was washed and dried, and then immersed in anhydrous ethanol; subsequently, it was placed on a silicon wafer with a pre-deposited metal conductive layer, and then pressed with a quartz cover glass to obtain an assembled AAO / Si composite template.

[0181] Step 2: Preparation of the first nano-zinc oxide film layer

[0182] (1) Prepare an electrolyte containing zinc: Add zinc oxide to a 3 mol / L NaOH solution, stir until the solution is clear, cool to room temperature, and set aside the electrolyte. The electrolyte contains 1 g of ZnO per 100 g of H2O;

[0183] (2) Using the AAO / Si composite template as the cathode and graphite (40x60 mm) as the anode, perform electrochemical deposition by the constant current method. Place the anode and cathode about 2 cm from the cell wall respectively, with a spacing of 8 cm, and control the current at 2.5 A / dm 2 , electro-deposit for 0.5 h, then clean the ZnO on the surface of the AAO / Si composite template with nitric acid solution, and dry it at 80 °C to obtain the AAO / Si composite template deposited with the first nano-zinc oxide film layer, which is used as composite template A.

[0184] Step 3: Preparation of the first nano-titanium dioxide film layer

[0185] (1) Prepare an electrolyte containing titanium: Pour 1 L of deionized water into a beaker with a magnetic stirrer, then put 5 g of TiF4 and 5 g of NiCl2·6H2O into the beaker, and continuously stir at room temperature for 30 minutes to obtain the electrolyte for standby. The electrolyte contains 0.04 M TiF4 and 0.02 M NiCl2;

[0186] (2) Insert a Pt electrode (anode) and a reference electrode Ag / AgCl electrode. Glue the composite template A to a thin copper wire as the cathode, and after inserting the template into the electrolyte, soak it for about 10 minutes to allow the electrolyte to enter the pores of the template. Control the deposition potential at -0.4 V and electro-deposit for 1.2 h. After the deposition is completed, take out the template and rinse it repeatedly with deionized water, then soak it in deionized water for 30 minutes to completely remove the electrolyte, and dry it at 80 °C to further deposit the first nano-titanium dioxide film layer on the surface of the first nano-zinc oxide film layer to obtain composite template B.

[0187] Step 4: Preparation of the magnetic nano-film layer

[0188] (1) Prepare an electro-deposition solution containing nickel, iron and gallium: Use 0.017 M (mol / L) of NiSO4·6H2O, 0.0075 M of FeSO4·7H2O, and 0.12 M of Ga2(SO4)3·18H2O as the main electro-deposition salts; 0.2 M of sodium citrate (C6H5Na3O7·2H2O), 0.3 M of ammonium sulfate as complexing agents, and ammonium sulfate also serves as the conductive salt of the electro-deposition solution, 0.5 M of boric acid as a pH buffer, 0.02 M of ascorbic acid as an antioxidant, 0.03 g / L of sodium dodecyl sulfate as a wetting agent, and finally adjust the pH of the electro-deposition solution to 3 with NaOH and H2SO4. The volume of the electro-deposition solution is 100 mL;

[0189] (2) Using composite template B as the cathode and graphite as the anode, electrochemical deposition is carried out in a two-electrode system at a constant voltage at room temperature. The deposition voltage is controlled at 2.5 V, and the electrodeposition is carried out for 2.5 h. Then, the electrodeposition solution on the surface of the template is cleaned with NaOH solution and dried at 80 °C. A magnetic nanolayer is further deposited on the surface of the first titanium dioxide nanolayer to obtain composite template C.

[0190] Step Five: Preparation of the second titanium dioxide nanolayer

[0191] (1) Prepare the titanium-containing electrolyte: Pour 1 L of deionized water into a beaker with a magnetic stirrer. Then, put 5 g of TiF4 and 5 g of NiCl2·6H2O into the beaker and continuously stir for 30 minutes at room temperature to obtain the standby electrolyte. The electrolyte contains 0.04 M TiF4 and 0.02 M NiCl2;

[0192] (2) Insert the Pt electrode (anode) and the reference electrode Ag / AgCl electrode. Glue the composite template C to a thin copper wire with silver glue as the cathode. After inserting the template into the electrolyte, soak it for about 10 minutes to allow the electrolyte to enter the pores of the template. Control the deposition potential at -0.4 V and carry out electrodeposition for 1.2 h. After the deposition is completed, take out the template and rinse it repeatedly with deionized water, then soak it in deionized water for 30 minutes to completely remove the electrolyte, and dry it at 80 °C. A second titanium dioxide nanolayer is further deposited on the surface of the magnetic nanolayer to obtain composite template D.

[0193] Step Six: Preparation of the second zinc oxide nanolayer

[0194] (1) Prepare the zinc-containing electrolyte: Add zinc oxide to 3 mol / L NaOH solution, stir until the solution is clear, and cool to room temperature to obtain the standby electrolyte. The electrolyte contains 1 g of ZnO per 100 g of H2O;

[0195] (2) Using composite template D as the cathode and graphite as the anode, electrochemical deposition is carried out by the equal current method. The anode and cathode are respectively placed about 2 cm away from the cell wall, with a spacing of 8 cm. Control the current at 2.5 A / dm 2 , and carry out electrodeposition for 0.5 h. Then, clean the ZnO on the surface of the template with nitric acid solution and dry it at 80 °C. A second zinc oxide layer is further deposited on the surface of the second titanium dioxide nanolayer.

[0196] Step 7: Slowly stick the 3M470 electroplating tape on the surface of the AAO / Si composite template. The nano-porous array of the AAO / Si composite template is loaded with 3D magnetic optically variable nanoparticles formed by a first nano-zinc oxide film layer, a first nano-titanium dioxide film layer, a magnetic nano-film layer, a second nano-titanium dioxide film layer, and a second nano-zinc oxide film layer. Press with your fingertip to make the tape and the AAO / Si composite template fully contact, and then slowly tear off the tape. The AAO template is torn off and stuck to the tape, and the remaining 3D magnetic optically variable nanoparticles are evenly arranged on the silicon wafer. Take off the 3D magnetic optically variable nanoparticles to obtain 3D magnetic optically variable nanoparticles.

[0197] The preparation method of the 3D magnetic anti-counterfeiting ink in this embodiment includes the following steps:

[0198] Weigh the raw materials according to mass percentages: 25% of 3D magnetic optically variable nanoparticles, 12% of colorant, 55% of binder, 3.7% of photoinitiator, and 4.3% of additives; among them, the binder is a mixture of epoxy acrylate and dipropylene glycol diacrylate with a mass ratio of 1:0.95, the additives are a mixture of defoamer, dispersant, and leveling agent, the photoinitiator is a mixture of 2-hydroxy-4-n-octyloxybenzophenone and 2,2-dimethoxy-2-phenylacetophenone, and the colorant is lightfast scarlet.

[0199] Mix the above-mentioned weighed raw materials evenly to obtain 3D magnetic anti-counterfeiting ink.

[0200] Comparative Example 1

[0201] Comparative Example 1 provides a magnetic anti-counterfeiting label. The difference from Example 1 is that the magnetic ink anti-counterfeiting layer in Comparative Example 1 does not contain 3D magnetic optically variable nanoparticles, but uses existing magnetic optically variable film fragments. The other layers and preparation method of the magnetic anti-counterfeiting label are the same as those in Example 1. The preparation of the existing magnetic optically variable film fragments refers to the preparation method in Example 1 of the patent with the publication number CN115874490A, including:

[0202] Step S01: Prepare a magnetic optically variable film: Using a vacuum evaporation coating machine, under vacuum conditions, deposit a magnetic pigment on a glass substrate 15-25 times repeatedly with an optical film layer as a cycle to form a periodic composite structure with multiple isolation layers and multiple magnetic optically variable films stacked; among them, the magnetic pigment is one or a mixture of iron oxide black and iron oxide brown.

[0203] Step S02: Separate the magnetic optically variable film: After the deposition is completed, take out the rigid substrate from the vacuum chamber and place it in an ethanol solvent for demolding, and at the same time separate the magnetic optically variable film in the periodic composite structure from the isolation layer to obtain the separated magnetic optically variable film.

[0204] Step S03, pulverize the magnetic optically variable film: Pulverize the magnetic optically variable film obtained in step S02 to obtain a plurality of magnetic optically variable film fragments with a particle size of 10 - 100 nm.

[0205] By observing the 3D random magnetic pattern digital anti-counterfeiting marks of Example 1 and Example 2 and the magnetic anti-counterfeiting mark of the comparative example from different angles respectively, the detection results are shown in Table 1. Among them, the optical color change angle is measured by a BYK-maci multi-angle colorimeter; the brightness of the optically variable bright strip is measured by a Roadvista932 retroreflective coefficient tester; the optically variable bright strip road is visually inspected.

[0206] Table 1

[0207] Project Unit Example 1 Example 2 Comparative Example 1 Photochromic angle ∠°(min) 22 21 36 Brightness of photochromic bright bar <![CDATA[cd / lx / m 2 > 582 575 382 Photochromic bright stripe pattern / Circular particle pattern Circular particle pattern Irregular

[0208] The test results in Table 1 show that the brightness of the optically variable bright strip of the 3D random magnetic pattern digital anti-counterfeiting mark of the present invention is significantly higher and brighter. At the same time, the optically variable bright strip of the 3D random magnetic pattern digital anti-counterfeiting mark of the present invention has obvious and regular circular particle patterns, and has higher recognition compared with the magnetic anti-counterfeiting mark of Comparative Example 1.

[0209] The preferred embodiments of the present invention have been specifically described above, but the present invention is not limited to the described embodiments. Those skilled in the art can also make various equivalent variations or substitutions without departing from the spirit of the present invention, and these equivalent variations or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A preparation method of a 3D random magnetic stripe digital anti-counterfeiting mark, characterized in that The 3D random magnetic pattern digital anti-counterfeiting label includes a 3D magnetic ink anti-counterfeiting layer, and the 3D magnetic ink anti-counterfeiting layer contains 3D magnetic photovariable nanoparticles. The 3D magnetic photovariable nanoparticles include, from bottom to top, a first nano-zinc oxide film layer, a first nano-titanium dioxide film layer, a magnetic nano-film layer, a second nano-titanium dioxide film layer, and a second nano-zinc oxide film layer; The preparation method of the 3D random magnetic pattern digital anti-counterfeiting label includes the following steps: Screen-print the 3D magnetic anti-counterfeiting ink on the surface of the PET plastic film layer, and then perform magnetic fixing and UV curing to form a 3D magnetic ink anti-counterfeiting layer with an anti-counterfeiting magnetic stripe area and an anti-counterfeiting QR code area; the 3D magnetic anti-counterfeiting ink contains the 3D magnetic photovariable nanoparticles; Perform inkjet printing on the surface of the PET plastic film layer and the 3D magnetic ink anti-counterfeiting layer to form a printing layer with a LOGO area and an anti-counterfeiting verification code area; Coat the surface of the PET plastic film layer, the 3D magnetic ink anti-counterfeiting layer, and the printing layer with UV varnish to form a scratch-resistant protective layer; Screen-print the scratch-off ink on the surface of the scratch-resistant protective layer to form an anti-counterfeiting verification code shielding layer; Write commodity information in the anti-counterfeiting magnetic stripe area of the 3D magnetic ink anti-counterfeiting layer; Coat an adhesive on the bottom surface of the PET plastic film layer to form an adhesive layer, then cover a release film layer on the bottom surface of the adhesive layer, and then perform die-cutting to obtain the 3D random magnetic pattern digital anti-counterfeiting label; The 3D magnetic photovariable nanoparticles are prepared by the AAO template method; The specific preparation process of the AAO template method is as follows: (1) Prepare a double-pass AAO template, and composite the double-pass AAO template with a silicon wafer to obtain an AAO / Si composite template; (2) Prepare a zinc-containing electrolyte solution. Using the AAO / Si composite template as the cathode and graphite as the anode, perform electrochemical deposition to obtain an AAO / Si composite template deposited with the first nano-zinc oxide film layer, which is used as composite template A; (3) Prepare a titanium-containing electrolyte solution. Using composite template A as the cathode, platinum as the anode, and silver / silver chloride as the reference electrode, perform electrochemical deposition to further deposit the first nano-titanium dioxide film layer on the surface of the first nano-zinc oxide film layer to obtain composite template B; (4) Prepare an electrodeposition solution containing nickel, iron, and gallium. Using composite template B as the cathode and graphite as the anode, adopt a two-electrode system to perform electrochemical deposition to further deposit the magnetic nano-film layer on the surface of the first nano-titanium dioxide film layer to obtain composite template C; (5) Prepare a titanium-containing electrolyte solution. Using composite template C as the cathode, platinum as the anode, and silver / silver chloride as the reference electrode, perform electrochemical deposition to further deposit the second nano-titanium dioxide film layer on the surface of the magnetic nano-film layer to obtain composite template D; (6) Prepare a zinc-containing electrolyte solution. Using composite template D as the cathode and graphite as the anode, perform electrochemical deposition to further deposit the second nano-zinc oxide film layer on the surface of the second nano-titanium dioxide film layer, and then remove the AAO / Si composite template to obtain the 3D magnetic photovariable nanoparticles.

2. The preparation method according to claim 1, characterized in that, The 3D magnetic optically variable nanoparticles are circular flake-like particles, and the diameter of the 3D magnetic optically variable nanoparticles is 450-500 nm, and the thickness is 100-160 nm.

3. The preparation method according to claim 1, characterized in that, The thickness of the first nano-zinc oxide film layer is 20-25 nm, the thickness of the first nano-titanium dioxide film layer is 15-30 nm, the thickness of the magnetic nano-film layer is 30-50 nm, the thickness of the second nano-titanium dioxide film layer is 15-30 nm, and the thickness of the second nano-zinc oxide film layer is 20-25 nm.

4. The preparation method according to claim 1, characterized in that, The addition amount of the 3D magnetic optically variable nanoparticles in the 3D magnetic ink anti-counterfeiting layer is 15-25 wt%.

5. The preparation method according to claim 1, wherein, The 3D random magnetic pattern digital anti-counterfeiting label further includes a release film layer, an adhesive layer, a PET plastic film layer, a printing layer, a scratch-resistant protective layer, and an anti-counterfeiting verification code shielding layer; the release film layer and the adhesive layer are arranged on the bottom surface of the PET plastic film layer, and the 3D magnetic ink anti-counterfeiting layer, the printing layer, the scratch-resistant protective layer, and the anti-counterfeiting verification code shielding layer are arranged on the surface of the PET plastic film layer.

6. The preparation method according to claim 5, characterized in that, The 3D magnetic ink anti-counterfeiting layer includes an anti-counterfeiting magnetic stripe area and an anti-counterfeiting QR code area, and the printing layer includes a LOGO area and an anti-counterfeiting verification code area; the 3D magnetic ink anti-counterfeiting layer is arranged on the surface of the PET plastic film layer, the LOGO area of the printing layer is arranged on the surface of the PET plastic film layer, the anti-counterfeiting verification code area of the printing layer is arranged on the surface of the 3D magnetic ink anti-counterfeiting layer, the scratch-resistant protective layer is arranged on the surfaces of the PET plastic film layer, the 3D magnetic ink anti-counterfeiting layer, and the printing layer, and the anti-counterfeiting verification code shielding layer is arranged on the surface of the scratch-resistant protective layer and is located above the anti-counterfeiting verification code area of the printing layer.

7. An article with anti-counterfeiting features, characterized in that, The product is provided with a 3D random magnetic pattern digital anti-counterfeiting label prepared by the preparation method according to any one of claims 1-6.

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