Stimuli-responsive fluorescent ink

Abstract

The invention relates to stimuli-responsive fluorescent ink which is prepared by mixing a fluorescent substance, an ink solvent, a thickening agent and a surfactant according to a specific proportion. The fluorescent ink disclosed by the invention can be printed on a printing stock in a combined form, and can present dynamic change of fluorescence intensity in different gas environments such as air, ammonia gas, volatile organic amine and volatile acid environments, so that space dynamic information encryption / decryption and reversible fluorescence switching of advanced dynamic anti-counterfeiting patterns and two-dimensional codes are realized; the problems that existing fluorescent ink is single in signal, poor in stability, high in cost, poor in using effect and prone to causing information leakage (counterfeiting) are effectively solved. Besides, the preparation method of the stimuli-responsive fluorescent ink provided by the invention has the characteristics of simple and convenient process and environmental protection, and the prepared stimuli-responsive fluorescent ink is stable in optical property, has better waterproofness, and is more convenient and reliable when being used for multi-layer and multi-dimensional information encryption and decryption and instant anti-counterfeiting printing of complex personalized dynamic anti-counterfeiting patterns.

Description

Technical Field

[0001] The invention belongs to the technical field of dynamic anti-counterfeiting and information encryption, and particularly relates to a preparation method of stimulus-responsive fluorescent ink and application thereof. Background Art

[0002] Fluorescent inks are used in areas such as information encryption and transmission systems, product anti-counterfeiting, and the prevention of counterfeiting of important documents. These inks are used to print invisible anti-counterfeiting markings, text, images, and other content. The fluorescent material used directly impacts the anti-counterfeiting performance of fluorescent inks. While significant progress has been made in the application of fluorescent materials in information encryption and anti-counterfeiting systems, many challenges remain in their practical application. Most fluorescent materials can suffer severe structural damage after external stimulation, preventing them from recovering to their original state and causing irreversible photophysical changes. This significantly limits their further application in anti-counterfeiting fluorescent inks. For example, patents such as CN116731560A, CN117210061A, and CN107043576B all involve novel molecular design and synthesis, inevitably leading to issues such as unclear structure-property relationships, complex preparation processes, and low yields. Anti-counterfeiting inks such as those in patents CN118290984A and CN115160855A mostly use water as a solvent, but the cured coating of these water-based anti-counterfeiting inks suffers from poor water resistance. Patents CN103666457B, CN107057463A, CN114561124B and other fluorescent inks can only achieve single static anti-counterfeiting, and their anti-counterfeiting ability is relatively weak. They are easy to be forged and it is difficult to achieve personalized instant anti-counterfeiting printing.

[0003] Based on these shortcomings, the aggregation-induced emission (AIE) properties of existing organic drug molecules are used to develop fluorescent inks that can achieve time-dependent reversible fluorescence switching. This can be used to encrypt multi-source dynamic spatial information, decode specific information under given conditions, and achieve advanced dynamic anti-counterfeiting. This is not only a simple, effective, and easily overlooked design strategy, but also has important practical value in the large-scale application of fluorescent inks. Summary of the Invention

[0004] The present invention aims to provide a method for preparing a stimuli-responsive fluorescent ink with dynamic, multi-signal characteristics and its application. Through creative combinations, various personalized preset patterns can be printed. Then, after exposure to environments such as ammonia / amines and air / volatile acids, the ink can achieve spatial dynamic information encryption and decryption, as well as reversible fluorescence switching of advanced dynamic anti-counterfeiting patterns and anti-counterfeiting QR codes. This approach aims to address the problems of existing fluorescent inks, such as their single signal, poor stability, limited effectiveness, high cost, and susceptibility to information leakage and counterfeiting.

[0005] The technical solutions of the present invention are as follows:

[0006] A stimulus-responsive fluorescent ink, characterized by comprising the following components in parts by mass:

[0007]

[0008] The fluorescent substance is a compound represented by formula I:

[0009]

[0010] Wherein, R1 is selected from any one of the following groups: -CH3, -H, -Cl; R2 is selected from any one of the following groups: -CH3, -CF3, -Cl; R3 is selected from any one of -H or -Cl; R4 is selected from any one of -CH or -N.

[0011] Furthermore, the ink solvent is an alcohol or an ester; the thickener is propylene glycol, ethylene glycol, butylene glycol, hydroxyethyl cellulose or polyvinyl pyrrolidone; and the surfactant is sodium dodecyl sulfate, hexadecyltrimethylammonium chloride, alkylphenol polyoxyethylene ether, glycerol polyoxypropylene ether or potassium perfluorooctane sulfonate.

[0012] Furthermore, the alcohol is at least one of methanol, ethanol, propanol, n-butanol and isopropanol; the ester is ethyl acetate, ethyl formate, propyl acetate, butyl acetate, etc.

[0013] Furthermore, the present invention provides a method for preparing the above-mentioned stimulus-responsive fluorescent ink, which is characterized in that: the fluorescent substance is dissolved in an ink solvent, and then a thickener and a surfactant are added, and mixed at an ultrasonic frequency of 20 to 60 kHz for 10 to 60 minutes to uniformly disperse the components to obtain the stimulus-responsive fluorescent ink.

[0014] Furthermore, the present invention provides a fluorescent ink combination that can be used for multi-level dynamic anti-counterfeiting and spatial dynamic information encryption / decryption. The fluorescent ink combination is composed of at least two of the aforementioned stimulus-responsive fluorescent inks, each stimulus-responsive fluorescent ink containing a different fluorescent substance, wherein the fluorescent substance is a compound represented by Formula I:

[0015]

[0016] Wherein, R1 is selected from any one of the following groups: -CH3, -H, -Cl; R2 is selected from any one of the following groups: -CH3, -CF3, -Cl; R3 is selected from any one of -H or -Cl; R4 is selected from any one of -CH or -N.

[0017] Preferably, the fluorescent ink combination consists of at least two of the stimulus-responsive fluorescent inks A, B, C, D, E, F, G, H, and I; wherein:

[0018] The fluorescent substance in ink A is compound 1, which is a compound represented by formula I, wherein R1 is -H, R2 is -CF3, R3 is -H, and R4 is -CH;

[0019] The fluorescent substance in ink B is compound 2, which is a compound represented by formula I, wherein R1 is -CH3, R2 is -Cl, R3 is -H, and R4 is -CH;

[0020] The fluorescent substance in ink C is compound 3, which is a compound represented by formula I, wherein R1 is -CH3, R2 is -CH3, R3 is -H, and R4 is -CH.

[0021] The fluorescent substance in ink D is compound 4, which is a compound represented by formula I, wherein R1 is -H, R2 is -Cl, R3 is -H, and R4 is -CH.

[0022] The fluorescent substance in ink E is compound 5, which is a compound represented by formula I, wherein R1 is -Cl, R2 is -Cl, R3 is -H, and R4 is -CH.

[0023] The fluorescent substance in ink F is compound 6, which is a compound represented by formula I, wherein R1 is -Cl, R2 is -CH3, R3 is -Cl, and R4 is -CH.

[0024] The fluorescent substance in ink G is compound 7, which is a compound represented by formula I, wherein R1 is -H, R2 is -CF3, R3 is -H, and R4 is -N.

[0025] The fluorescent substance in ink H is compound 8, which is a compound represented by formula I, wherein R1 is -CH3, R2 is -Cl, R3 is -H, and R4 is -N.

[0026] The fluorescent substance in ink I is compound 9, which is a compound represented by formula I, wherein R1 is -CH3, R2 is -CF3, R3 is -H, and R4 is -N.

[0027] More preferably, the fluorescent ink combination consists of stimulus-responsive fluorescent inks A, B and C.

[0028] Furthermore, the present invention provides a method for applying the stimulus-responsive fluorescent ink in dynamic anti-counterfeiting and spatial dynamic information encryption / decryption, which is characterized by comprising the following steps:

[0029] 1) printing the stimulus-responsive fluorescent ink onto a substrate according to a preset graphic pattern;

[0030] 2) Under ultraviolet light, dynamic anti-counterfeiting information or spatial dynamic information for dynamic information encryption / decryption operations is generated based on the dynamic changes in the fluorescence intensity and color of the image and text on the substrate in different gas environments; wherein:

[0031] The gas environment includes: an ammonia environment, a volatile organic amine environment, an air environment, and a volatile acid environment; the graphics and text include: patterns, text, and QR codes.

[0032] Furthermore, the present invention provides a method for applying the fluorescent ink combination in multi-level dynamic anti-counterfeiting and spatial dynamic information encryption / decryption, which is characterized by comprising the following steps:

[0033] 1) Printing all stimulus-responsive fluorescent inks in the fluorescent ink combination onto a substrate according to a preset graphic pattern;

[0034] 2) Under ultraviolet light, generating multi-level dynamic anti-counterfeiting information or multi-level spatial dynamic information for dynamic information encryption / decryption operations based on the asynchronous dynamic changes in the intensity and color of the different fluorescence exhibited by the image and text on the substrate due to different inks in different gas environments;

[0035] Among them, the gas environment includes: ammonia environment, volatile organic amine environment, air environment, and volatile acid environment; the graphics and texts include: patterns, texts, and QR codes.

[0036] Furthermore, when the fluorescent ink combination is composed of at least two of the above-mentioned stimulus-responsive fluorescent inks A to I, a method for using the fluorescent ink combination in multi-level spatial dynamic information encryption / decryption is characterized by comprising the following steps:

[0037] 1) Printing all stimulus-responsive fluorescent inks in the fluorescent ink combination onto a substrate in accordance with a preset encrypted information graphic pattern; the encrypted information graphic pattern includes: patterns, text, and QR codes;

[0038] 2) placing the substrate in an ammonia or volatile organic amine environment under ultraviolet light until the blue fluorescent area of ​​the printed image on the substrate shows discernible encrypted information due to the asynchronous change in fluorescence intensity and color of the different inks over time, and then disappears as the fluorescence decays;

[0039] 3) The printed material is then placed in air or a volatile acid environment until the encrypted information image is restored to be clearly discernible and then returns to a blue fluorescence in which the encrypted information image is no longer discernible.

[0040] Furthermore, the invention provides a method for applying a fluorescent ink combination consisting of at least two of the above-mentioned stimuli-responsive fluorescent inks A to I in multi-level dynamic anti-counterfeiting, characterized by comprising the following steps:

[0041] 1) Printing all stimulus-responsive fluorescent inks in the fluorescent ink combination onto a substrate in accordance with a preset graphic pattern; the graphic pattern includes: patterns, text, and QR codes;

[0042] 2) placing the substrate in an ammonia or volatile organic amine environment under ultraviolet light until the substrate exhibits blue fluorescence and the discernible image or text becomes invisible due to the decay of the fluorescence intensity;

[0043] 3) The printed material is then placed in air or a volatile acid environment until the image gradually returns to its original fluorescent color.

[0044] The stimulus-responsive fluorescent ink of the present invention is printed on a substrate and can show dynamic changes in fluorescence intensity in different gas environments such as air, ammonia, volatile organic amines, and volatile acid environments, thereby realizing spatial dynamic information encryption / decryption and reversible fluorescence switching of advanced dynamic anti-counterfeiting patterns and QR codes, effectively solving the problems of existing fluorescent inks with single signals, poor stability, high cost, poor use effect, and easy information leakage (forgery). In addition, the method for preparing the stimulus-responsive fluorescent ink provided by the present invention has the characteristics of simple process and green environmental protection. The prepared stimulus-responsive fluorescent ink has stable optical properties and good waterproofness, and is more convenient and reliable for multi-level, multi-dimensional information encryption and decryption, and instant anti-counterfeiting printing of complex personalized dynamic anti-counterfeiting patterns. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 The dynamic changes in fluorescence of the anti-counterfeiting two-dimensional code printed with the fluorescent ink combination in Example 1.

[0046] Figure 2 This is the dynamic change of fluorescence after the fluorescent ink combination of Example 2 is used to print encrypted information.

[0047] Figure 3 This is the dynamic change of fluorescence after the fluorescent ink combination of Example 3 is used to print a personalized pattern.

[0048] Figure 4 This is the dynamic change of fluorescence after the fluorescent ink combination of Example 4 is used to print a personalized pattern.

[0049] Figure 5 This is the dynamic change of fluorescence after the fluorescent ink combination of Example 5 is used to print a personalized pattern. Specific implementation plan

[0050] The following detailed description of the technical solutions of the present invention is provided in conjunction with the accompanying drawings. However, the examples do not limit the present invention in any way. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional in the art.

[0051] Example 1

[0052] Stimuli-responsive fluorescent inks A, B, and C were prepared using the following raw materials in parts by mass:

[0053]

[0054] The specific preparation method is: dissolving the fluorescent substance in the ink solvent, then adding a thickener and a surfactant, and mixing at an ultrasonic frequency of 20 to 60 kHz for 10 to 60 minutes to uniformly disperse the components to obtain a stimulus-responsive fluorescent ink.

[0055] Among them, for stimulus-responsive fluorescent ink A, the ink solvent is ethanol, the thickener is glycerol, the surfactant is sodium dodecylsulfonate, and the fluorescent substance is compound 1, which is a compound represented by the aforementioned formula I, wherein R1 is -H, R2 is -CF3, R3 is -H, and R4 is -CH; for stimulus-responsive fluorescent ink B, the ink solvent is isopropyl alcohol, the thickener is ethylene glycol, the surfactant is hexadecyltrimethylammonium chloride, and the fluorescent substance is compound 2, which is a compound represented by the aforementioned formula I, wherein R1 is -CH3, R2 is -Cl, R3 is -H, and R4 is -CH; for stimulus-responsive fluorescent ink C, the ink solvent is ethyl acetate, the thickener is butanediol, the surfactant is alkylphenol polyoxyethylene ether, and the fluorescent substance is compound 3, which is a compound represented by the aforementioned formula I, wherein R1 is -CH3, R2 is -CH3, R3 is -H, and R4 is -CH.

[0056] A fluorescent ink combination consisting of stimulus-responsive fluorescent inks A, B, and C with a mass ratio of 1:1:1 is used to print on the surface of the substrate according to a preset QR code pattern.

[0057] The printed QR code is colorless under sunlight, but appears bright blue under 365nm ultraviolet light. The QR code is identifiable and can be scanned and read using a mobile phone. When the QR code is placed in an ammonia environment, the fluorescence intensity of the three inks in the QR code decays at different rates until the QR code content cannot be recognized; then the QR code is exposed to air, and the fluorescence intensity of the three inks recovers to bright blue fluorescence at different rates, and the entire image and text are clearly visible. The whole change process is as follows Figure 1 In this process, the dynamic changes in the fluorescence intensity and color of the three inks generate multi-level dynamic anti-counterfeiting information.

[0058] Example 2

[0059] Stimuli-responsive fluorescent inks A, B, and C were prepared using a method substantially the same as in Example 1. The difference was that the addition ratio of the following raw materials was changed to:

[0060]

[0061] In addition, the ink solvent used to prepare the three inks is all isopropyl alcohol; the thickener is all glycerol; and the surfactant is all sodium dodecyl sulfonate.

[0062] The prepared stimulus-responsive fluorescent inks A, B, and C are combined into a fluorescent ink combination in a mass ratio of 1:1:1, and encrypted information is printed on the surface of the substrate.

[0063] The encrypted information printed on the substrate is invisible in sunlight and only shows bright blue fluorescence under 365nm ultraviolet light, making it impossible to distinguish the image and text. When the substrate is placed in an ammonia environment, the blue fluorescent area will show discernible encrypted information due to the asynchronous changes in the fluorescence intensity and color of the three inks over time. After a long enough time, the encrypted information will become invisible as the fluorescence decays, and the information will be completely erased. After that, the substrate is exposed to air, and the encrypted information will gradually become clear and discernible again, and then finally return to blue fluorescence that is indistinguishable. The information is erased. The whole change process is as follows: Figure 2 The dynamic changes of the three fluorescence intensities and colors in this process generate multi-level spatial dynamic information that can be used for dynamic information encryption / decryption operations.

[0064] Example 3

[0065] Stimuli-responsive fluorescent inks A, B, and C were prepared using a method substantially the same as in Example 1. The difference was that the addition ratio of the following raw materials was changed to:

[0066]

[0067] In addition, the ink solvents used to prepare the three inks are all ethanol; the thickeners are all butanediol; and the surfactants are all hexadecyltrimethylammonium chloride.

[0068] The prepared stimulus-responsive fluorescent inks A, B, and C were combined into a fluorescent ink combination in a mass ratio of 3:2:2, and a preset personalized pattern (butterfly pattern) was printed on the surface of the substrate.

[0069] The personalized pattern printed on the substrate is invisible in sunlight, but it shows a clearly discernible blue butterfly-shaped fluorescent pattern under 365nm ultraviolet light. When the substrate is placed in an ammonia environment, the blue butterfly-shaped fluorescent pattern gradually becomes invisible due to the asynchronous decay of the fluorescence intensity of the three inks; then, when the substrate is exposed to air, the blue butterfly-shaped fluorescent pattern gradually becomes clearly discernible. The whole change process is as follows Figure 3 The dynamic changes in fluorescence intensity and color during this process generate multi-level spatial dynamic information, which can be used to design personalized advanced dynamic anti-counterfeiting patterns.

[0070] Example 4

[0071] Stimuli-responsive fluorescent inks A, B, and C were prepared using a method substantially the same as in Example 1. The difference was that the addition ratio of the following raw materials was changed to:

[0072]

[0073] In addition, the ink solvent used to prepare the three inks is ethyl acetate; the thickener is ethylene glycol; and the surfactant is alkylphenol polyoxyethylene ether.

[0074] The prepared stimulus-responsive fluorescent inks A, B, and C were combined into a fluorescent ink combination in a mass ratio of 2:3:2, and a preset personalized pattern (robot pattern) was printed on the surface of the substrate.

[0075] The personalized pattern printed on the substrate is invisible in sunlight, but it shows a clearly identifiable blue robot-like fluorescent pattern under 365nm ultraviolet light. When the substrate is placed in an ammonia environment, the blue robot-like fluorescent pattern gradually becomes invisible due to the asynchronous decay of the fluorescence intensity of the three inks; then, when the substrate is placed in an HCl volatile acid environment, the blue robot-like fluorescent pattern quickly becomes clearly identifiable. The entire change process is as follows Figure 4 The dynamic changes in fluorescence intensity and color during this process generate multi-level spatial dynamic information, which can be used to design personalized advanced dynamic anti-counterfeiting patterns.

[0076] Example 5

[0077] Stimuli-responsive fluorescent inks A, B, and C were prepared using a method substantially the same as in Example 1. The difference was that the addition ratio of the following raw materials was changed to:

[0078]

[0079]

[0080] In addition, the ink solvents used to prepare the three inks are all ethanol; the thickeners are all butanediol; and the surfactants are all hexadecyltrimethylammonium chloride.

[0081] The prepared stimulus-responsive fluorescent inks A, B, and C were combined into a fluorescent ink combination in a mass ratio of 2:2:3, and a preset personalized pattern (tree) was printed on the surface of the substrate.

[0082] The personalized pattern printed on the substrate is invisible in sunlight, but it shows a clearly discernible blue dendritic fluorescent pattern under 365nm ultraviolet light. When the substrate is placed in an ammonia environment, the blue dendritic fluorescent pattern gradually becomes invisible due to the asynchronous decay of the fluorescence intensity of the three inks; then, when the substrate is exposed to air, the blue dendritic fluorescent pattern gradually becomes clearly discernible. The whole change process is as follows Figure 5 The dynamic changes in fluorescence intensity and color during this process generate multi-level spatial dynamic information, which can be used to design personalized advanced dynamic anti-counterfeiting patterns.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, although the present invention has been described in detail with reference to the aforementioned embodiment. Based on the design principles of the present invention, those skilled in the art can achieve the same technical effects by adjusting the material selection, optimizing the raw material ratio, or performing equivalent replacement of technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A stimulus-responsive fluorescent ink, characterized in that: The components include the following by mass: The fluorescent substance is a compound represented by formula I: Wherein, R1 is selected from any one of the following groups: -CH3, -H, -Cl; R2 is selected from any one of the following groups: -CH3, -CF3, -Cl; R3 is selected from any one of -H or -Cl; R4 is selected from any one of -CH or -N.

2. A method for preparing the stimulus-responsive fluorescent ink according to claim 1, characterized in that: The fluorescent substance is dissolved in an ink solvent, and then a thickener and a surfactant are added, and the mixture is mixed at an ultrasonic frequency of 20 to 60 kHz for 10 to 60 minutes to uniformly disperse the components to obtain the stimulus-responsive fluorescent ink.

3. A fluorescent ink combination comprising several stimuli-responsive fluorescent inks according to claim 1, characterized in that: Each stimulus-responsive fluorescent ink constituting the fluorescent ink combination contains a different fluorescent substance, wherein the fluorescent substance is a compound represented by formula I; Wherein, R1 is selected from any one of the following groups: -CH3, -H, -Cl; R2 is selected from any one of the following groups: -CH3, -CF3, -Cl; R3 is selected from any one of -H or -Cl; R4 is selected from any one of -CH or -N.

4. The fluorescent ink combination according to claim 3, characterized in that: The fluorescent ink combination consists of at least two of the stimulus-responsive fluorescent inks A, B, C, D, E, F, G, H, and I; wherein: The fluorescent substance in ink A is compound 1, which is a compound represented by formula I, wherein R1 is -H, R2 is -CF3, R3 is -H, and R4 is -CH; The fluorescent substance in ink B is compound 2, which is a compound represented by formula I, wherein R1 is -CH3, R2 is -Cl, R3 is -H, and R4 is -CH; The fluorescent substance in ink C is compound 3, which is a compound represented by formula I, wherein R1 is -CH3, R2 is -CH3, R3 is -H, and R4 is -CH. The fluorescent substance in ink D is compound 4, which is a compound represented by formula I, wherein R1 is -H, R2 is -Cl, R3 is -H, and R4 is -CH. The fluorescent substance in ink E is compound 5, which is a compound represented by formula I, wherein R1 is -Cl, R2 is -Cl, R3 is -H, and R4 is -CH. The fluorescent substance in ink F is compound 6, which is a compound represented by formula I, wherein R1 is -Cl, R2 is -CH3, R3 is -Cl, and R4 is -CH. The fluorescent substance in ink G is compound 7, which is a compound represented by formula I, wherein R1 is -H, R2 is -CF3, R3 is -H, and R4 is -N. The fluorescent substance in ink H is compound 8, which is a compound represented by formula I, wherein R1 is -CH3, R2 is -Cl, R3 is -H, and R4 is -N. The fluorescent substance in ink I is compound 9, which is a compound represented by formula I, wherein R1 is -CH3, R2 is -CF3, R3 is -H, and R4 is -N.

5. The method for applying the stimulus-responsive fluorescent ink in dynamic anti-counterfeiting and spatial dynamic information encryption / decryption according to claim 1, characterized in that The steps include: 1) printing the stimulus-responsive fluorescent ink onto a substrate according to a preset graphic pattern; 2) Under ultraviolet light, dynamic anti-counterfeiting information or spatial dynamic information for dynamic information encryption / decryption operations is generated based on the dynamic changes in the fluorescence intensity and color of the image and text on the substrate in different gas environments; wherein: The gas environment includes: an ammonia environment, a volatile organic amine environment, an air environment, and a volatile acid environment; the graphics and text include: patterns, text, and QR codes.

6. The method for applying the fluorescent ink combination as claimed in claim 3 in multi-level dynamic anti-counterfeiting and spatial dynamic information encryption / decryption, characterized in that The steps include: 1) Printing all stimulus-responsive fluorescent inks in the fluorescent ink combination onto a substrate according to a preset graphic pattern; 2) Under ultraviolet light, multi-level dynamic anti-counterfeiting information or multi-level spatial dynamic information for dynamic information encryption / decryption operations is generated based on the asynchronous dynamic changes in the intensity and color of the different fluorescence presented by the graphics on the substrate due to different inks in different gas environments.

7. The method for applying the fluorescent ink combination according to claim 3 in multi-level dynamic anti-counterfeiting and spatial dynamic information encryption / decryption, characterized in that: The gas environment includes: air environment, ammonia environment, volatile organic amine environment, and volatile acid environment; the graphics and text include: patterns, text, and QR codes.

8. The method for using the fluorescent ink combination in multi-level spatial dynamic information encryption / decryption as claimed in claim 4, characterized in that The steps include: 1) Printing all stimulus-responsive fluorescent inks in the fluorescent ink combination onto a substrate in accordance with a preset encrypted information graphic pattern; the encrypted information graphic pattern includes: patterns, text, and QR codes; 2) placing the substrate in an ammonia or volatile organic amine environment under ultraviolet light until the blue fluorescent area of ​​the printed image on the substrate shows discernible encrypted information due to the asynchronous change in fluorescence intensity and color of the different inks over time, and then disappears as the fluorescence decays; 3) The printed material is then placed in air or a volatile acid environment until the encrypted information image is restored to be clearly discernible and then returns to a blue fluorescence in which the encrypted information image is no longer discernible.

9. The method for applying the fluorescent ink combination in multi-level dynamic anti-counterfeiting as claimed in claim 4, characterized in that The steps include: 1) Printing all stimulus-responsive fluorescent inks in the fluorescent ink combination onto a substrate in accordance with a preset graphic pattern; the graphic pattern includes: patterns, text, and QR codes; 2) placing the substrate in an ammonia or volatile organic amine environment under ultraviolet light until the substrate exhibits blue fluorescence and the discernible image or text becomes invisible due to the decay of the fluorescence intensity; 3) The printed material is then placed in air or a volatile acid environment until the image gradually returns to its original fluorescent color.

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