An electron beam invisible anti-counterfeiting printing label and its manufacturing method

Abstract

The present invention relates to the technical field of invisible anti-counterfeiting labels, and particularly to an electron beam invisible anti-counterfeiting printed label and a manufacturing method thereof, which specifically include the following steps: S1: Generation of an anti-counterfeiting code electronic graphic; S2: Fabrication of a mask plate; S3: Preparation of a concentrated solution of a nano-zinc oxide photonic crystal thin film; S4: Printing and encapsulation of the electron beam invisible anti-counterfeiting printed label. The electron beam invisible anti-counterfeiting printed label of the present invention can achieve the hiding of the label by using a nano-zinc oxide photonic crystal thin film, and a high-resolution microscopic pattern can be obtained by using a more delicate mask plate, with a high process difficulty, which can effectively avoid being counterfeited and ensure the anti-counterfeiting performance.

Description

Technical Field

[0001] The present invention relates to the technical field of invisible anti-counterfeiting labels, and particularly to an electron beam invisible anti-counterfeiting printed label and a manufacturing method thereof. Background Art

[0002] In daily work and life, along with the increasing demand level for people to identify the authenticity of items, the anti-counterfeiting technology has been continuously updated and iterated. Currently, most traditional optical anti-counterfeiting technologies have defects such as low technical content, easy deciphering of structural combinations, and easy light bleaching of colors. Moreover, with the development and popularization of high-resolution devices such as digital cameras, scanners, and printers, counterfeiters can easily produce high-quality counterfeit products.

[0003] Common anti-counterfeiting technologies include laser anti-counterfeiting technology and digital anti-counterfeiting technology, and both of these technologies have their respective defects. First, taking the laser rainbow embossed holographic graphic anti-counterfeiting technology as an example for laser anti-counterfeiting technology, it is a visible graphic information produced on a product by applying laser rainbow hologram plate-making technology and embossing replication technology. The latest laser holographic transfer technology has organically combined multiple technologies from different disciplines such as laser holographic stamping, computer lithography, special plate-making, precision electroforming thickening and thinning, and high-precision peeling to first make a transferable holographic plastic film, and then transfer it to the paper surface to make laser holographic transfer paper. As more and more manufacturers master the laser anti-counterfeiting technology, the technology of anti-counterfeiting by changing the image through light irradiation has fallen behind, and at the same time, the accuracy of observing the image change with the naked eye has also been greatly reduced, making it inconvenient for consumers to distinguish the authenticity.

[0004] Secondly, digital anti-counterfeiting technology sets a unique code for each product and stores the code in a database. Consumers compare the code in the database through the network. After successful query, the code is deleted and cannot be used again. The defect of this kind of technology is that it cannot be repeatedly queried, and other personnel in the entire commodity circulation link, such as dealers and agents, cannot query. Moreover, not every consumer will query the anti-counterfeiting code, and counterfeiters can still obtain the code by recycling unqueried labels to counterfeit new labels, making it difficult to completely prevent counterfeiting.

[0005] Therefore, it is necessary to provide an anti-counterfeiting label that is convenient for consumers to distinguish the authenticity, has good hiding performance, and is not easily counterfeited. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, one of the purposes of the present invention is to provide a manufacturing method of an electron beam invisible anti-counterfeiting printed label, which has good hiding performance and is not easily counterfeited. Specifically:

[0007] An electron beam invisible anti-counterfeiting printed label and a manufacturing method thereof include the following steps:

[0008] S1: Generation of anti-counterfeiting code electronic graphics;

[0009] S2: Fabrication of mask plate;

[0010] S3: Preparation of nano-zinc oxide photonic crystal thin film concentrate;

[0011] S4: Printing and encapsulation of electron beam invisible anti-counterfeiting printing label.

[0012] Further, the nano-zinc oxide photonic crystal thin film concentrate in step S3 is prepared from nano-zinc oxide colloidal solution by the following method: Mix 3 - 4 parts of nano-zinc oxide colloidal solution with 2.5 - 3.5 parts of ethylene glycol and 1.5 - 2 parts of ethoxylated trimethylolpropane triacrylate, and then supplement ethanol to a total volume of 120 parts to form a mixture; Heat the mixture until the ethanol evaporates completely, and after cooling, obtain a supersaturated solution of nano-zinc oxide colloidal particles in ethylene glycol and ethoxylated trimethylolpropane triacrylate, that is, obtain the nano-zinc oxide photonic crystal thin film concentrate.

[0013] Further, in step S3, the heating temperature of the mixture is 85 - 90 °C.

[0014] Further, the nano-zinc oxide colloidal solution is prepared through the following steps:

[0015] S31: Synthesis of nano-zinc oxide colloidal sphere suspension:

[0016] Mix zinc acetate dihydrate and diglycol in a ratio of 0.01 - 0.03 mol∶100 - 200 ml, heat in a reflux condenser to 150 - 160 °C, continuously heat and stir for 1 - 1.5 h, then cool to room temperature, and then perform centrifugation to extract the supernatant for standby;

[0017] S32: Carboxylation modification of the surface of nano-zinc oxide colloidal spheres:

[0018] Uniformly disperse silane coupling agent and succinic anhydride in dimethylformamide, perform magnetic stirring at a temperature of 100 - 120 °C for 2 - 3 h, then add the supernatant obtained in step S31, and at the same time add deionized water;

[0019] Continue to stir at a temperature of 100 - 120 °C for 4 - 5 h, then use a centrifuge to separate nano-zinc oxide, and after multiple alcohol washing and centrifugation separations, obtain carboxylated modified nano-zinc oxide. Finally, disperse the carboxylated modified nano-zinc oxide in absolute ethanol to obtain a carboxylated modified nano-zinc oxide colloidal solution;

[0020] S33: Synthesis of nano-zinc oxide colloidal solution:

[0021] After heating 100 - 200 mL of diethylene glycol solution to 130 - 140 °C in a condensing reflux device, add the carboxylated modified nano-zinc oxide colloidal solution prepared in step S32, continue to heat up to 160 °C, and continuously heat and stir at this temperature for 4 - 5 h until the solution becomes transparent; wash the product 4 times with absolute ethanol, and finally disperse it in 20 mL of absolute ethanol to obtain a nano-zinc oxide colloidal solution.

[0022] Further, the silane coupling agent is KH-550.

[0023] Further, in step S32, the silane coupling agent, succinic anhydride, and dimethylformamide are mixed in a ratio of 0.01 - 0.02 mol∶0.01 - 0.02 mol∶100 ml.

[0024] Further, the generation of the anti-counterfeiting code electronic graphic in step S1 includes generating an anti-counterfeiting code electronic graphic for various information such as product origin information, variety, brand, environment, and processing process through an anti-counterfeiting code generator;

[0025] The mask plate described in step S2 is made according to the shape of the anti-counterfeiting electronic graphic in step S1.

[0026] Further, step S4 includes the following specific operation processes:

[0027] S41: Coat a liquid film with a thickness of 1 - 1.5 mm on the surface of the substrate with the nano-zinc oxide photonic crystal thin film concentrate, and irradiate it with ultraviolet light for 15 - 20 minutes to obtain a nano-zinc oxide photonic crystal thin film;

[0028] S42: Drop a mixture of ethylene glycol and poly(ethylene glycol) diacrylate on the obtained nano-zinc oxide photonic crystal thin film for infiltration;

[0029] S43: Wipe dry the infiltrated nano-zinc oxide photonic crystal thin film, coat a curing adhesive with a thickness of 0.5 - 1 mm around the nano-zinc oxide photonic crystal thin film by means of a rubber roller coating method, cover an OPP film on the area of the nano-zinc oxide photonic crystal thin film and the area brushed with the photocuring adhesive, place the mask plate with the anti-counterfeiting pattern above the photonic crystal thin film, irradiate it with an electron beam for 10 - 15 seconds, then remove the mask plate to obtain a colloidal crystal printed matter with the pattern invisible through deformation; the area outside the projection area of the mask plate is cured and crosslinked under electron beam irradiation to realize the encapsulation of the colloidal crystal printed matter in the OPP film.

[0030] Further, in step S42, the volume ratio of ethylene glycol to poly(ethylene glycol) diacrylate in the mixture of ethylene glycol and poly(ethylene glycol) diacrylate is 1∶1, and the infiltration time is 40 - 80 minutes.

[0031] The second object of the present invention is to provide an electron beam invisible anti-counterfeiting printing label, which is convenient for consumers to distinguish the authenticity and is not easy to be imitated.

[0032] An electron beam invisible anti-counterfeiting printing label is prepared by the above method, and the printing substrate can be one of materials such as paper, plastic, iron sheet, etc.

[0033] Beneficial effects:

[0034] 1. The photonic crystal thin film prepared by the present invention is an elastic thin film that is very sensitive to external forces. The thin film contains a large amount of ethylene glycol, has very good elasticity, and has a very sensitive structural color change response to external forces. By squeezing and stretching, the photonic crystal thin film can produce a reflection wavelength change of 150 nm, almost covering the entire visible light range. The structural color change response speed of the photonic crystal thin film under the action of external forces is very fast and is reversible multiple times.

[0035] 2. The present invention uses poly(ethylene glycol) diacrylate as a crosslinking agent for the nano-zinc oxide photonic crystal thin film. During the label production process, a mask plate is made according to the anti-counterfeiting code electronic pattern, and the light-impermeable part, that is, the projection area of the mask plate, is the anti-counterfeiting code electronic pattern. The anti-counterfeiting code electronic pattern covered by the mask plate is not crosslinked by electron beam irradiation, while the light-transmitting part is crosslinked by electron beam irradiation. Under the condition of not being affected by external forces, the optical signals of the uncrosslinked anti-counterfeiting code pattern and the surrounding crosslinked nano-zinc oxide photonic crystal thin film are very close, so the anti-counterfeiting code pattern does not show any color. However, when subjected to external force extrusion and stretching, the area of the nano-zinc oxide photonic crystal thin film blocked by the mask plate (i.e., the anti-counterfeiting code area) will deform, resulting in color change, and the color difference will make the anti-counterfeiting code pattern appear.

[0036] 3. A more refined mask plate can be used to obtain a high-resolution micro-pattern, which is difficult in process, can effectively avoid being imitated, and ensure the anti-counterfeiting performance.

[0037] 4. The electron beam invisible anti-counterfeiting printing label uses a colorless photonic crystal thin film, which can realize the hiding of the label.

[0038] 5. The electron beam is used to firmly paste the colloidal crystal printing on the surface of the product or its packaging surface. The electron beam is a cold light source, and the curing belongs to cold curing, which will not cause the printing substrate, the product and the packaging surface to be deformed by heat. The electron beam is used to realize the crosslinking change of the crystal thin film, and the use of initiators can be avoided. Thereby, the migration of small molecule initiators on the packaging surface is avoided, and the product is prevented from being polluted.

[0039] 6. The introduction of carboxyl groups on the surface of nano-zinc oxide not only improves the interfacial compatibility between the nanoparticles and the matrix, but more importantly, the broad reaction range and easy ionization characteristics of carboxyl groups endow the nanoparticles with high reactivity, effectively improving the adhesion of the electron beam invisible anti-counterfeiting printing label on the printing substrate. Description of the Drawings

[0040] Figure 1 is a schematic flow chart of the method for manufacturing an electron beam invisible anti-counterfeiting printing label provided by the present invention;

[0041] Figure 2 is a schematic structural diagram of the electron beam invisible anti-counterfeiting printing label provided by the present invention.

[0042] Illustration:

[0043] 1. Printing substrate; 2. Nano-zinc oxide photonic crystal film; 21. Crosslinked nano-zinc oxide photonic crystal film; 22. Anti-counterfeiting code electronic pattern that has not been crosslinked; 4. Curing adhesive; 3. OPP film. Detailed Embodiments

[0044] For the convenience of those skilled in the art, the present invention will be further described below in conjunction with embodiments. The content mentioned in the embodiments does not limit the present invention.

[0045] The raw materials used in the present invention can all be obtained commercially.

[0046] Anti-counterfeiting labels are widely used for the protection of commodities. In the past, label paper was usually used. By using special materials or setting special colors, labels were made and attached to the surface of commodities for anti-counterfeiting. However, with the development of technology, the anti-counterfeiting labels used in the past, even if they use special materials and have special colors, are very easy to be forged, and the anti-counterfeiting effect of the anti-counterfeiting labels is getting weaker and weaker.

[0047] After existing two-dimensional codes, barcodes or other anti-counterfeiting patterns are scanned by equipment, the information contained therein can be obtained, such as the origin, model, price, manufacturer link advertisement, etc. of the commodity. The present invention adds an invisible anti-counterfeiting function on the basis of two-dimensional code and barcode identification.

[0048] In the present invention, the photonic crystal film can achieve non-color display under non-extrusion conditions. After extrusion, the colloidal crystal film can produce a reflection wavelength change of 150 nm, almost covering the entire visible light range, realizing the hiding of the anti-counterfeiting label. The anti-counterfeiting information of the anti-counterfeiting label prepared by the present invention can be divided into two layers. The first layer is for anti-counterfeiting through the hiding and extrusion color-changing functions of the label; the second layer is to obtain the label information through instrument testing.

[0049] Refer to Figure 1, An electron beam invisible anti-counterfeiting printing label and its manufacturing method, comprising the following steps:

[0050] S1: Generation of anti-counterfeiting code electronic graphics:

[0051] Generate anti-counterfeiting code electronic graphics for various information such as product origin information, variety, brand, environment, and processing process through an anti-counterfeiting code generator.

[0052] S2: Fabrication of the mask plate:

[0053] Fabricate the mask plate according to the shape of the anti-counterfeiting electronic graphics.

[0054] S3: Preparation of nano-zinc oxide photonic crystal thin film concentrate:

[0055] First, a nano-zinc oxide colloidal solution needs to be prepared. The nano-zinc oxide colloidal solution is prepared through the following steps:

[0056] S31: Synthesis of nano-zinc oxide colloidal sphere suspension:

[0057] Mix zinc acetate dihydrate (Zn(CH3COO)2)·2H2O) and diethylene glycol (DEG) in a ratio of 0.01 - 0.03 mol∶100 - 200 ml, heat in a condensation reflux device to 150 - 160 °C, continuously heat and stir for 1 - 1.5 h, then cool to room temperature, and then perform centrifugation to extract the supernatant for standby.

[0058] S32: Carboxylation modification of the surface of nano-zinc oxide colloidal spheres:

[0059] Uniformly disperse 0.01 - 0.02 mol of KH-550 and 0.01 - 0.02 mol of succinic anhydride in 100 ml of dimethylformamide (DMF), perform magnetic stirring at a temperature of 100 - 120 °C for 2 - 3 h, then add the supernatant obtained in step S31, and at the same time add deionized water. The silane coupling agent is KH-550.

[0060] Continue to stir at a temperature of 100 - 120 °C for 4 - 5 h, then use a centrifugation device to separate nano-zinc oxide. After multiple alcohol washing and centrifugation separations, carboxylated modified nano-zinc oxide is obtained. Finally, the carboxylated modified nano-zinc oxide is dispersed in absolute ethanol to obtain a carboxylated modified nano-zinc oxide colloidal solution.

[0061] S33: Synthesis of nano-zinc oxide colloidal solution:

[0062] Add 100 - 200 mL of diethylene glycol (DEG) solution to a three-necked flask. After heating to 130 - 140 °C in a reflux condenser, add the carboxylated modified nano-zinc oxide colloidal solution prepared in step S32. Continue to heat up to 160 °C and continuously heat and stir at this temperature for 4 - 5 h until the solution becomes transparent. Wash the product 4 times with absolute ethanol and finally disperse it in 20 mL of absolute ethanol to obtain a nano-zinc oxide colloidal solution.

[0063] Secondly, prepare a concentrated nano-zinc oxide photonic crystal film solution. The concentrated nano-zinc oxide photonic crystal film solution is prepared from the nano-zinc oxide colloidal solution by the following method:

[0064] Mix 3 - 4 parts of the nano-zinc oxide colloidal solution with 2.5 - 3.5 parts of ethylene glycol and 1.5 - 2 parts of ethoxylated trimethylolpropane triacrylate (ETPTA), and then add ethanol to make the total volume 120 parts to form a mixture. Heat the mixture to 85 - 90 °C until the ethanol completely evaporates. After cooling, obtain a supersaturated solution of nano-zinc oxide colloidal particles in ethylene glycol and ethoxylated trimethylolpropane triacrylate (ETPTA), that is, obtain the concentrated nano-zinc oxide photonic crystal film solution.

[0065] S4: Printing and encapsulation of electron beam invisible anti-counterfeiting printing labels:

[0066] S41: Coating a liquid film with a thickness of 1 - 1.5 mm on the surface of the printing substrate by means of a rubber roller coating with the concentrated nano-zinc oxide photonic crystal film solution, and irradiating with ultraviolet light for 15 - 20 minutes to obtain a nano-zinc oxide photonic crystal film; among them, the printing substrate can be one of materials such as paper, plastic, iron sheet, etc.;

[0067] S42: Drop a mixture of ethylene glycol and poly(ethylene glycol) diacrylate (PEGDA700) with a volume ratio of 1:1 on the obtained nano-zinc oxide photonic crystal film for infiltration, and the infiltration time is 40 - 80 minutes;

[0068] S43: Wipe dry the infiltrated nano-zinc oxide photonic crystal film, coat a curing adhesive with a thickness of 0.5 - 1 mm around the nano-zinc oxide photonic crystal film by means of a rubber roller coating. Cover the OPP film on the area of the nano-zinc oxide photonic crystal film and the area coated with the photocurable adhesive. Place the mask plate with the anti-counterfeiting pattern above the photonic crystal film, and irradiate with an electron beam for 10 - 15 seconds, then remove the mask plate to obtain a colloidal crystal print with the pattern invisible through deformation.

[0069] The pattern of the mask plate is consistent with the shape of the anti-counterfeiting electronic graphic. When the mask plate is placed above the photonic crystal thin film, the projection area of the mask plate partially blocks the further cross-linking of poly(ethylene glycol) diacrylate (PEGDA700) and the nano-zinc oxide photonic crystal thin film. The area outside the projection area of the mask plate is cured and cross-linked under electron beam irradiation, realizing the encapsulation of the colloidal crystal print with a pattern invisible through deformation in the OPP film.

[0070] Referring to Figure 2 , the present invention also provides an electron beam invisible anti-counterfeiting printing label, which is obtained by the above method, including printing a nano-zinc oxide photonic crystal thin film 2 on the surface of the substrate 1 by means of a rubber roller coating method, a cured adhesive 4 coated around the nano-zinc oxide photonic crystal thin film by means of a rubber roller coating method, and an OPP film 3 covered on the nano-zinc oxide photonic crystal thin film and the area coated with the cured adhesive by means of a laminating machine. Among them, the nano-zinc oxide photonic crystal thin film 2 includes a cross-linked nano-zinc oxide photonic crystal thin film 21 and an anti-counterfeiting code electronic graphic 22 that has not been cross-linked.

[0071] Example 1

[0072] An electron beam invisible anti-counterfeiting printing label and its manufacturing method include the following steps:

[0073] S1: Generation of the anti-counterfeiting code electronic graphic:

[0074] In this embodiment, the anti-counterfeiting label is illustrated by taking a two-dimensional code as an example. The two-dimensional code generator is already a very mature existing technology. First, various information such as product origin information, variety, brand, environment, and processing process is input into the anti-counterfeiting code generator, and then a two-dimensional code with specified meaning information is generated.

[0075] The printing substrate is selected as paper.

[0076] S2: Fabrication of the mask plate:

[0077] According to the shape of the two-dimensional code generated in S1, a mask plate is fabricated. The mask plate is obtained by etching a mask pattern on a substrate, and the two-dimensional code pattern is the so-called mask pattern. At the same time, the anti-counterfeiting label described in the present invention is not limited to a two-dimensional code, and can also be a bar code, other pattern types of anti-counterfeiting labels, etc. The solid part of the mask plate is the graphic of the anti-counterfeiting label.

[0078] S3: Preparation of the nano-zinc oxide photonic crystal thin film concentrate:

[0079] First, a nano-zinc oxide colloidal solution needs to be prepared, and the nano-zinc oxide colloidal solution is prepared through the following steps:

[0080] S31: Synthesis of the nano-zinc oxide colloidal sphere suspension:

[0081] Mix 0.02 mol of zinc acetate dihydrate (Zn(CH3COO)2·2H2O) with 150 mL of diethylene glycol (DEG), heat the mixture to 155 °C in a reflux condenser, continuously heat and stir for 1.5 h, then cool to room temperature. After subjecting the obtained colloidal solution to centrifugation in a centrifuge, extract the supernatant and retain it for the next step.

[0082] S32: Carboxylation modification of the surface of nano-zinc oxide colloidal spheres:

[0083] Disperse 0.015 mol of KH-550 and 0.015 mol of succinic anhydride evenly in 100 ml of dimethylformamide (DMF), magnetically stir the mixture at 100 °C for 3 h, then add the supernatant obtained in step S31 to this system, and at the same time add 20 ml of deionized water;

[0084] Continue to magnetically stir at 100 °C for 5 h, then separate the nano-zinc oxide by an ultra-high-speed centrifuge. After washing and centrifuging with alcohol multiple times, the carboxylated modified nano-zinc oxide is obtained. Finally, disperse it in 20 mL of absolute ethanol to obtain a carboxylated modified nano-zinc oxide colloidal solution.

[0085] S33: Synthesis of nano-zinc oxide colloidal solution:

[0086] Add 150 mL of diethylene glycol (DEG) solution to a three-necked flask. When heated to 140 °C in a reflux condenser, add the carboxylated modified nano-zinc oxide solution obtained in step S32, and then continue to heat to 160 °C. Continuously heat and stir at this temperature for 5 h. During this process, it can be seen that the liquid gradually changes from semi-transparent to milky transparent. Wash the product 4 times with absolute ethanol, and finally disperse it in 20 mL of absolute ethanol to obtain a nano-zinc oxide colloidal solution.

[0087] Secondly, prepare a concentrated nano-zinc oxide photonic crystal film solution. The concentrated nano-zinc oxide photonic crystal film solution is prepared from the nano-zinc oxide colloidal solution by the following method:

[0088] Mix 4 mL of nano-zinc oxide colloidal solution with 3.5 mL of ethylene glycol and 2 mL of ethoxylated trimethylolpropane triacrylate (ETPTA), and supplement ethanol to a total volume of 120 mL. Evaporate the ethanol in the mixture completely at 90 °C, and after cooling, obtain a supersaturated solution of nano-zinc oxide colloidal particles in ethylene glycol and ethoxylated trimethylolpropane triacrylate (ETPTA), that is, obtain a concentrated nano-zinc oxide photonic crystal film solution.

[0089] S4: Printing and encapsulation of electron beam invisible anti-counterfeiting printing labels:

[0090] S41: Coat a liquid film with a thickness of 1.5 mm on the surface of the printing substrate by means of a rubber roller coating using the nano-zinc oxide photonic crystal thin film concentrate, and irradiate with ultraviolet light for 20 minutes to obtain the nano-zinc oxide photonic crystal thin film.

[0091] S42: Drop a mixed solution of ethylene glycol and poly(ethylene glycol) diacrylate (PEGDA700) (volume ratio 1:1) above the obtained nano-zinc oxide photonic crystal thin film and soak for 1 hour.

[0092] S43: Wipe dry the soaked nano-zinc oxide photonic crystal thin film, coat 1 mm of curing adhesive around the nano-zinc oxide photonic crystal thin film by means of a rubber roller coating, completely cover the OPP film on the nano-zinc oxide photonic crystal thin film and the area brushed with the photocuring adhesive, place the mask plate with the anti-counterfeiting pattern above the photonic crystal thin film, irradiate with an electron beam for 15 seconds, and then remove the mask plate to obtain a colloidal crystal printed matter with the pattern invisible through deformation.

[0093] The pattern of the mask plate is consistent with the shape of the anti-counterfeiting electronic graphic. When the mask plate is placed above the photonic crystal thin film, the projected area of the mask plate partially blocks the further cross-linking of poly(ethylene glycol) diacrylate (PEGDA700) and the nano-zinc oxide photonic crystal thin film. The area outside the projected area of the mask plate is cured and cross-linked under the electron beam irradiation, realizing the encapsulation of the colloidal crystal printed matter with the pattern invisible through deformation inside the OPP film.

[0094] Example 2

[0095] An electron beam invisible anti-counterfeiting printing label and its manufacturing method, comprising the following steps:

[0096] S1: Generation of the anti-counterfeiting code electronic graphic:

[0097] In this embodiment, the anti-counterfeiting label is illustrated by taking a two-dimensional code as an example. The two-dimensional code generator is already a very mature existing technology. First, input various information such as product origin information, variety, brand, environment, and processing process into the anti-counterfeiting code generator, and then generate a two-dimensional code with information of specified meaning.

[0098] The printing substrate is selected as paper.

[0099] S2: Fabrication of the mask plate:

[0100] Fabricate the mask plate according to the shape of the two-dimensional code generated in S1. The mask plate is obtained by etching a mask pattern on a substrate, and the two-dimensional code graphic is the said mask pattern. At the same time, the anti-counterfeiting label described in the present invention is not limited to the two-dimensional code, and can also be a bar code, other pattern types of anti-counterfeiting labels, etc. The solid part of the mask plate is the graphic of the anti-counterfeiting label.

[0101] S3: Preparation of nano-zinc oxide photonic crystal thin film concentrate:

[0102] First, a nano-zinc oxide colloidal solution needs to be prepared. The nano-zinc oxide colloidal solution is prepared through the following steps:

[0103] S31: Synthesis of nano-zinc oxide colloidal sphere suspension:

[0104] Mix 0.03 mol of zinc acetate (Zn(CH3COO)2·2H2O) with 200 mL of diethylene glycol (DEG), heat it to 160 °C in a reflux condenser, continuously heat and stir for 1 h, then cool to room temperature. After centrifuging the obtained colloidal solution in a centrifuge, extract the supernatant and retain it for the next step.

[0105] S32: Carboxylation modification of the surface of nano-zinc oxide colloidal spheres:

[0106] Uniformly disperse 0.02 mol of KH-550 and 0.02 mol of succinic anhydride in 100 ml of dimethylformamide (DMF), magnetically stir at 100 °C for 2.5 h, then add the supernatant obtained in step S31 to this system, and at the same time add 20 ml of deionized water.

[0107] Continue to magnetically stir at 100 °C for 4.5 h, then separate nano-zinc oxide with an ultra-high speed centrifuge. After washing and centrifuging with alcohol multiple times, carboxylated modified nano-zinc oxide is obtained. Finally, it is dispersed in 20 mL of absolute ethanol to obtain a carboxylated modified nano-zinc oxide colloidal solution.

[0108] S33: Synthesis of nano-zinc oxide colloidal solution:

[0109] Add 200 mL of diethylene glycol (DEG) solution to a three-necked flask. When heated to 140 °C in a reflux condenser, add the carboxylated modified nano-zinc oxide solution obtained in step S32, then continue to heat to 160 °C, and continuously heat and stir at this temperature for 4.5 h. During this process, it can be seen that the liquid gradually changes from semi-transparent to milky transparent. Wash the product 4 times with absolute ethanol, and finally disperse it in 20 mL of absolute ethanol to obtain a nano-zinc oxide colloidal solution.

[0110] Secondly, prepare the nano-zinc oxide photonic crystal thin film concentrate. The nano-zinc oxide photonic crystal thin film concentrate is prepared from the nano-zinc oxide colloidal solution by the following method:

[0111] Mix 3.5 mL of nano-zinc oxide colloidal solution with 3 mL of ethylene glycol and 1.5 mL of ethoxylated trimethylolpropane triacrylate (ETPTA), and add ethanol to make the total volume 120 mL. Evaporate the ethanol in the mixture completely at 85 - 90 °C. After cooling, obtain a supersaturated solution of nano-zinc oxide colloidal particles in ethylene glycol and ethoxylated trimethylolpropane triacrylate (ETPTA), that is, obtain the concentrated solution of nano-zinc oxide photonic crystal film.

[0112] S4: Printing and encapsulation of electron beam invisible anti-counterfeiting printing label:

[0113] S41: Coating a liquid film with a thickness of 1 mm on the surface of the printing substrate by means of a rubber roller coating method using the concentrated solution of nano-zinc oxide photonic crystal film, and irradiating with ultraviolet light for 20 minutes to obtain a nano-zinc oxide photonic crystal film.

[0114] S42: Drop a mixture of ethylene glycol and poly(ethylene glycol) diacrylate (PEGDA700) (volume ratio 1:1) above the obtained nano-zinc oxide photonic crystal film and soak for 1 hour.

[0115] S43: Wipe dry the soaked nano-zinc oxide photonic crystal film, coat 0.5 mm of curing adhesive around the nano-zinc oxide photonic crystal film by means of a rubber roller coating method, cover the entire area of the nano-zinc oxide photonic crystal film and the area coated with photocuring adhesive with an OPP film using a laminating machine. Place a mask plate with an anti-counterfeiting pattern above the photonic crystal film, irradiate with an electron beam for 10 seconds, then remove the mask plate to obtain a colloidal crystal print with a pattern invisible through deformation.

[0116] The pattern of the mask plate is the same as the shape of the anti-counterfeiting electronic graphic. When the mask plate is placed above the photonic crystal film, it blocks the further crosslinking of PEGDA700 and the nano-zinc oxide photonic crystal film. The unblocked area by the mask plate is cured and crosslinked under electron beam irradiation, realizing the encapsulation of the colloidal crystal print with a pattern invisible through deformation in the OPP film.

[0117] Comparative Example 1

[0118] Comparative Example 1 omitted the step of surface carboxylation modification of nano-zinc oxide colloidal spheres in Example 1, and directly added the nano-zinc oxide colloidal sphere suspension when the diethylene glycol (DEG) solution of 200 mL was condensed and refluxed to 140 °C to obtain a nano-zinc oxide colloidal solution. The remaining steps are the same as those in Example 1.

[0119] Comparative Example 2

[0120] In Comparative Example 2, the poly(ethylene glycol) diacrylate (PEGDA700) component in Step S42 of Example 2 was omitted, and the remaining steps were the same as those in Example 2.

[0121] The electron beam invisible anti-counterfeiting printing labels obtained in the above Examples 1-2 and Comparative Examples 1-2 were coated on the same kind of paper, and the anti-counterfeiting display and adhesion tests were carried out on the electron beam invisible anti-counterfeiting printing labels. The test results are shown in Table 1.

[0122] Among them, the test methods are as follows:

[0123] 1. Anti-counterfeiting display test: The visual method was adopted, and the change of the anti-counterfeiting code was observed by stretching and squeezing the electron beam invisible anti-counterfeiting printing label.

[0124] 2. Adhesion performance test: The test was carried out according to the requirements of GB / T2792-2014 "Test Method for Peel Strength of Adhesive Tape".

[0125] Table 1: Performance test results of electron beam invisible anti-counterfeiting printing labels:

[0126]

[0127] It can be seen from Table 1 that the electron beam invisible anti-counterfeiting printing labels of Examples 1-2 and Comparative Example 1 showed the process of display and hiding of the anti-counterfeiting code after stretching and squeezing. Comparative Example 2 did not show the process of display and hiding of the anti-counterfeiting code. The main reason is that Comparative Example 2 did not add the poly(ethylene glycol) diacrylate (PEGDA700) component, and could not achieve further cross-linking with the nano-zinc oxide photonic crystal film. Neither the anti-counterfeiting code electronic graphic area nor the nano-zinc oxide photonic crystal film area was cross-linked. When subjected to external force extrusion and stretching, the nano-zinc oxide photonic crystal film area (i.e., the anti-counterfeiting code area) blocked by the mask plate and the nano-zinc oxide photonic crystal film area not blocked by the mask plate produced the same deformation, and no color difference could be generated, so the anti-counterfeiting code pattern could not be displayed.

[0128] The peel strengths of Comparative Example 1 and Comparative Example 2 were significantly lower than those of Example 1 and Example 2. In Comparative Example 1, since the surface carboxylation modification step of the nano-zinc oxide colloidal spheres was not carried out, the adhesion to the printing substrate decreased. In Comparative Example 2, due to the lack of addition of the poly(ethylene glycol) diacrylate (PEGDA700) component, further cross-linking with the nano-zinc oxide photonic crystal film could not be achieved, and the cross-linking degree of the film was insufficient, resulting in poor adhesion.

[0129] In summary, it can be seen that the present invention has the above-mentioned excellent characteristics, so that it can enhance the effectiveness that has never been seen in the prior art in use and has practicality, and becomes a product with extremely high practical value.

[0130] The above content is only a preferred embodiment of the present invention. For those of ordinary skill in the art, based on the idea of the present invention, there will be changes in the specific implementation manner and application scope. The content of this specification should not be construed as a limitation on the present invention.

Claims

1. An electron beam invisible anti-counterfeiting printing label and its manufacturing method, characterized in that: It includes the following steps: S1: Generation of anti-counterfeiting code electronic graphics; S2: Fabrication of a mask plate; S3: Preparation of a nano-zinc oxide photonic crystal thin film concentrate; S4: Printing and encapsulation of an electron beam invisible anti-counterfeiting printed label; Among them, the nano-zinc oxide photonic crystal thin film concentrate in step S3 is prepared from a nano-zinc oxide colloidal solution by the following method: Mix 3 - 4 parts of nano-zinc oxide colloidal solution with 2.5 - 3.5 parts of ethylene glycol and 1.5 - 2 parts of ethoxylated trimethylolpropane triacrylate, and then supplement ethanol to a total volume of 120 parts to form a mixed solution; Heat the mixed solution until the ethanol completely volatilizes, and after cooling, obtain a supersaturated solution of nano-zinc oxide colloidal particles in ethylene glycol and ethoxylated trimethylolpropane triacrylate, that is, obtain the nano-zinc oxide photonic crystal thin film concentrate.

2. The electron beam invisible anti-counterfeiting printing label and its manufacturing method according to claim 1, characterized in that: In step S3, the heating temperature of the mixed solution is 85 - 90 °C.

3. The electron beam invisible anti-counterfeiting printing label and its manufacturing method according to claim 1, characterized in that: The nano-zinc oxide colloidal solution is prepared through the following steps: S31: Synthesis of nano-zinc oxide colloidal sphere suspension: Mix zinc acetate dihydrate and diglycol in a ratio of 0.01 - 0.03 mol : 100 - 200 ml, heat to 150 - 160 °C in a condensation reflux device, continuously heat and stir for 1 - 1.5 h, then cool to room temperature, and then perform centrifugation to extract the supernatant for standby; S32: Carboxylation modification of the surface of nano-zinc oxide colloidal spheres: Uniformly disperse a silane coupling agent and succinic anhydride in dimethylformamide, perform magnetic stirring at a temperature of 100 - 120 °C for 2 - 3 h, then add the supernatant prepared in step S31, and at the same time add deionized water; Continue to stir at a temperature of 100 - 120 °C for 4 - 5 h, then use a centrifugal device to separate nano-zinc oxide. After multiple alcohol washing and centrifugal separation, carboxylated modified nano-zinc oxide is obtained. Finally, disperse the carboxylated modified nano-zinc oxide in absolute ethanol to obtain a carboxylated modified nano-zinc oxide colloidal solution; S33: Synthesis of nano-zinc oxide colloidal solution: Heat 100 - 200 mL of diethylene glycol solution to 130 - 140 °C in a condensation reflux device, then add the carboxylated modified nano-zinc oxide colloidal solution prepared in step S32, continue to heat to 160 °C, and continuously heat and stir at this temperature for 4 - 5 h until the solution becomes transparent; Wash the product 4 times with absolute ethanol and finally disperse it in 20 mL of absolute ethanol to obtain a nano-zinc oxide colloidal solution.

4. The electron beam invisible anti-counterfeiting printing label and its manufacturing method according to claim 3, characterized in that: The silane coupling agent is KH-550.

5. The electron beam invisible anti-counterfeiting printing label and its manufacturing method according to claim 4, characterized in that: In step S32, the silane coupling agent, succinic anhydride and dimethylformamide are mixed in a ratio of 0.01 - 0.02 mol : 0.01 - 0.02 mol : 100 ml.

6. The electron beam invisible anti-counterfeiting printing label and its manufacturing method according to claim 1, characterized in that: The generation of the anti-counterfeiting code electronic graphics in step S1 includes generating anti-counterfeiting code electronic graphics for various information such as product origin information, variety, brand, environment, and processing process through an anti-counterfeiting code generator; The mask plate in step S2 is made according to the shape of the anti-counterfeiting electronic graphics in step S1.

7. The electron beam invisible anti-counterfeiting printing label and its manufacturing method according to claim 1, characterized in that: Step S4 includes the following specific operation processes: S41: Coat a liquid film with a thickness of 1 - 1.5 mm of the nano-zinc oxide photonic crystal thin film concentrate on the surface of the printing substrate, and irradiate it with ultraviolet light for 15 - 20 minutes to obtain the nano-zinc oxide photonic crystal thin film; S42: Drop the mixed solution of ethylene glycol and poly(ethylene glycol) diacrylate on the obtained nano-zinc oxide photonic crystal thin film for infiltration; S43: Wipe dry the infiltrated nano-zinc oxide photonic crystal thin film, coat a curing adhesive with a thickness of 0.5 - 1 mm around the nano-zinc oxide photonic crystal thin film by means of a rubber roller coating method, cover an OPP film on the area of the nano-zinc oxide photonic crystal thin film and the area where the photocuring adhesive is brushed, place a mask plate with an anti-counterfeiting pattern above the photonic crystal thin film, irradiate it with an electron beam for 10 - 15 seconds, then remove the mask plate to obtain a colloidal crystal printed matter with the pattern invisible through deformation; the area outside the projection area of the mask plate is cured and crosslinked under the electron beam irradiation to realize the encapsulation of the colloidal crystal printed matter in the OPP film.

8. The electron beam invisible anti-counterfeiting printing label and its manufacturing method according to claim 7, characterized in that: In the step S42, the volume ratio of ethylene glycol to poly(ethylene glycol) diacrylate in the mixed solution of ethylene glycol and poly(ethylene glycol) diacrylate is 1:1, and the infiltration time is 40 - 80 minutes.

9. An electron beam invisible anti-counterfeiting printing label, characterized in that, The electronic beam invisible anti-counterfeiting printing label is prepared by the method described in claims 1 - 8, and the printing substrate can be one of materials such as paper, plastic, iron sheet, etc.

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