Fluorescent wrinkle anti-counterfeiting identification label and preparation method thereof

Abstract

The invention relates to the technical field of anti-counterfeit labels, in particular to a fluorescent wrinkle anti-counterfeit identification label and a preparation method thereof. The fluorescent wrinkle anti-counterfeiting identification label comprises a supporting material layer, a wrinkle substrate layer, a wrinkle film layer and a luminescent material layer, the fold base layer is located on the upper layer of the supporting material layer, and the fold layer is formed by curing polydimethylsiloxane; the wrinkled film layer is positioned on the upper layer of the wrinkled substrate layer and is formed by crosslinking polyvinyl alcohol; the light-emitting material layer is distributed in the wrinkled film layer, and a light-emitting material in the light-emitting material layer is full-inorganic cesium lead halide perovskite nanocrystals. According to the prepared anti-counterfeit label, strong fluorescence is formed on the wrinkle structure, a first-level anti-counterfeit structure is formed, meanwhile, perovskite can be induced to form random particles, and multi-layer anti-counterfeit is formed.

Description

Technical Field

[0001] The invention relates to the technical field of anti-counterfeiting labels, and in particular to a fluorescent wrinkled anti-counterfeiting identification label and a preparation method thereof. Background Art

[0002] With the development of the times and the progress of society, people pay more and more attention to the protection of intellectual property rights and the protection of the rights and interests of merchants and consumers. The development of anti-counterfeiting technology is of vital importance. In recent years, due to the mastery of anti-counterfeiting technology by counterfeiters and the emergence of counterfeiting technologies, anti-counterfeiting technology is facing further upgrades and updates, and anti-counterfeiting methods are gradually developing towards diversification and complexity. At present, surface pattern anti-counterfeiting faces problems such as pattern randomness, pattern information storage level and recognition accuracy. It is imperative to construct anti-counterfeiting patterns with high complexity, high security and physical non-clonability.

[0003] As the commonly used surface pattern anti-counterfeiting technologies, wrinkle anti-counterfeiting and fluorescent anti-counterfeiting have relatively small information storage levels, low security levels, and are easily imitated and counterfeited. Combining the two anti-counterfeiting methods to construct a fluorescent wrinkle dual anti-counterfeiting pattern greatly increases the level of anti-counterfeiting information storage and improves its security level, but its preparation method is often difficult and costly, and it is difficult to ensure a stable pattern after preparation.

[0004] Perovskite materials have the optical properties of high photoluminescence quantum yield, narrow half-peak width and tunable fluorescence emission performance, and are an effective fluorescent anti-counterfeiting material. The double-layer structure constructed by polyvinyl alcohol and polydimethylsiloxane can form a fold pattern with physical unclonable properties. Based on the fold structure and combined with the fluorescence properties of perovskite materials, the complexity and security of the anti-counterfeiting pattern can be improved.

[0005] Here, we provide a perovskite / polyvinyl alcohol wrinkle anti-counterfeiting pattern, which utilizes the water-induced effect of perovskite nanocrystals and polyvinyl alcohol wrinkles to prepare and achieve a certain degree of morphology control, thereby obtaining a multi-responsive, multi-level anti-counterfeiting pattern, achieving stable wrinkle texture, and fluorescent spots distributed along the wrinkle texture, thereby obtaining a highly secure anti-counterfeiting identification label. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a method to solve the problems raised in the above background technology.

[0007] A fluorescent wrinkled anti-counterfeiting identification label comprises a supporting material layer, a wrinkled base layer, a wrinkled film layer and a luminescent material layer; the wrinkled base layer is located on the upper layer of the supporting material layer, and the wrinkled layer is formed by curing polydimethylsiloxane (PDMS); the wrinkled film layer is located on the upper layer of the wrinkled base layer, and the wrinkled film layer is formed by cross-linking polyvinyl alcohol (PVA); the luminescent material layer is distributed in the wrinkled film layer, and the luminescent material in the luminescent material layer is all-inorganic cesium lead halide perovskite nanocrystals.

[0008] Furthermore, the supporting material layer is a glass substrate.

[0009] A method for preparing a fluorescent wrinkled anti-counterfeiting identification label comprises the following steps:

[0010] S1. Evenly mix polydimethylsiloxane and curing agent, evenly apply them to a clean glass sheet, set the oven temperature to 80°C and cure for 2 hours, and perform plasma treatment after curing to obtain a wrinkled base layer;

[0011] S2, uniformly mixing PVA, a photocrosslinking agent and a solvent of deionized water, dissolving them at 90°C to obtain a polyvinyl alcohol solution, uniformly coating the polyvinyl alcohol solution on the wrinkled base layer obtained in step S1, setting an oven temperature of 60°C for curing for 1 hour, and placing it under a 254nm ultraviolet lamp for ultraviolet crosslinking for 2 hours after curing to obtain a wrinkled film layer;

[0012] S3, mixing cesium bromide, lead bromide and deionized water, and performing ultrasonic treatment for 5 minutes to uniformly decompose the mixed solution, and taking the upper layer of liquid as the perovskite precursor solution after standing for 15 minutes, and dropping the perovskite precursor solution on the wrinkled film layer obtained in step S2, and obtaining the luminescent material layer by spin coating centrifugation method or low-temperature evaporation method;

[0013] S4. The support material layer, the wrinkled base layer, the wrinkled film layer and the luminescent material layer obtained in the above steps are encapsulated by PDMS to obtain a fluorescent wrinkled anti-counterfeiting identification label.

[0014] Furthermore, in step S1, the mass ratio of polydimethylsiloxane to curing agent is 50:1.

[0015] Furthermore, in step S2, the photocrosslinking agent is sodium benzoate, the mass ratio of the photocrosslinking agent to polyvinyl alcohol is 3:47, and the sum of the mass volume concentrations of PVA and the photocrosslinking agent in the polyvinyl alcohol solution is 200-250 mg / ml.

[0016] Furthermore, the mass ratio of the cesium bromide, lead bromide and deionized water is 6.4:11:1000.

[0017] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0018] 1. The perovskite fluorescent wrinkle anti-counterfeiting identification label provided by the present invention combines PVA / PDMS wrinkles with perovskite fluorescent nanocrystals. The PVA / PDMS wrinkles constructed by the spin coating method give full play to their own water responsiveness and morphology controllability. The perovskite precursor solution with water as the solvent reduces pollution and harmful components. The prepared fluorescent wrinkle pattern has a macroscopically controllable morphology and a stable fluorescent effect, and emits green fluorescence under ultraviolet light;

[0019] 2. The perovskite fluorescent wrinkle anti-counterfeiting identification label provided by the present invention combines the excellent anti-counterfeiting performance of perovskite nanocrystals with the advantages of stable and efficient anti-counterfeiting of polyvinyl alcohol wrinkles. Compared with simple wrinkle anti-counterfeiting and fluorescent anti-counterfeiting, it shows better anti-counterfeiting performance;

[0020] 3. In the present invention, the function between PDMS and PVA is to form wrinkles. PDMS is a relatively soft rubber-like elastomer, and cross-linked PVA is a relatively hard polymer material. Under the action of water, modulus mismatch occurs to form wrinkles. The wrinkles of this PVA / PDMS are water-responsive. Wrinkles appear quickly after contacting water and disappear or become smaller after water evaporates. During the evaporation process, water will carry perovskite ions into PVA. The cross-linked network of PVA will restrict the migration of perovskite ions. The perovskite particles migrate to the concave part of the wrinkles during the evaporation process and finally crystallize on PVA, so the main fluorescent part will be formed on the concave part of the wrinkles.

[0021] 4. In the present invention, when the anti-counterfeiting mark is formed, a strong fluorescence is formed on the concave part of the fold, forming a layer of anti-counterfeiting, and fluorescent particles are randomly distributed in the non-concave part of the fold, forming a double-layer anti-counterfeiting effect. While ensuring the anti-counterfeiting ability, a large number of anti-counterfeiting marks with concave fluorescent structures that cannot be forged can be quickly screened out. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The process flow chart of preparing the fluorescent wrinkled anti-counterfeiting identification label of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of the fluorescent wrinkled anti-counterfeiting identification label prepared by the present invention during the evaporation and crystallization process of perovskite particles (1, perovskite precursor particles; 2, swollen PVA; 3, perovskite nanocrystals; 4, perovskite fluorescent band);.

[0024] Figure 3 This is a luminescence image of the fluorescent wrinkled anti-counterfeiting identification label prepared in Example 1 of the present invention under a 365nm ultraviolet lamp;

[0025] Figure 4This is a luminescence image of the fluorescent wrinkled anti-counterfeiting identification label prepared in Example 2 of the present invention under a 365nm ultraviolet lamp;

[0026] Figure 5 This is a luminescence image of the fluorescent wrinkled anti-counterfeiting identification label prepared in Example 3 of the present invention under a 365nm ultraviolet lamp;

[0027] Figure 6 for Figure 3 A local enlarged high-definition schematic diagram;

[0028] Figure 7 This is a luminescence image of the fluorescent wrinkled anti-counterfeiting identification label prepared in Comparative Example 1 of the present invention under a 365nm ultraviolet lamp;

[0029] Figure 8 This is a luminescence image of the fluorescent wrinkled anti-counterfeiting identification label prepared in Comparative Example 2 of the present invention under a 365nm ultraviolet lamp. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] See also Figures 1 to 8 , the present invention provides:

[0032] A fluorescent wrinkled anti-counterfeiting identification label comprises a supporting material layer, a wrinkled base layer, a wrinkled film layer and a luminescent material layer; the wrinkled base layer is located on the upper layer of the supporting material layer, and the wrinkled layer is formed by PDMS curing; the wrinkled film layer is located on the upper layer of the wrinkled base layer, and the wrinkled film layer is formed by PVA cross-linking; the luminescent material layer is distributed in the wrinkled film layer, and the luminescent material in the luminescent material layer is all-inorganic cesium lead halide perovskite nanocrystals.

[0033] In the present invention, the mixing mass ratio of PDMS and its curing agent is required to be 50:1, and they are mixed and stirred evenly. The model of PDMS is Dow Corning Sylgard PDMS184, and the curing agent is a 10% concentration of chloroplatinic acid isopropanol solution. Let it stand for a period of time to defoam. When the bubbles inside are invisible to the naked eye, a certain amount of the mixed PDMS is dripped at the center of a clean glass sheet, and a uniform coating is performed using a glue spreader, and the mixture is placed in an oven for high-temperature curing. In the present invention, the parameters of the glue spreader are preferably 300rpm 3s, 500rpm 60s; in the present invention, the curing temperature is preferably 80°C, and the curing time is preferably 2h.

[0034] In the present invention, the PDMS layer prepared above needs to be subjected to plasma treatment to increase the hydrophilicity of its surface, and a wrinkled base layer is obtained after the treatment; in the present invention, the power of the plasma cleaning machine in the plasma treatment is 50%, and the treatment time is 45 seconds.

[0035] In the present invention, the mixing ratio of PVA and its photocrosslinker is required to be 47:3. They are mixed and a certain amount of deionized water is added to prepare a polyvinyl alcohol solution of a certain concentration; the sum of the mass volume concentrations of PVA and the photocrosslinker in the polyvinyl alcohol solution is 200-250 mg / ml; a certain amount of the mixed polyvinyl alcohol solution is dripped at the center of the glass sheet for constructing the wrinkled base layer, and a coating machine is used to evenly spin coat the sheet, and the sheet is placed in an oven for heat preservation and curing; in the present invention, the parameters of the coating machine are preferably 300 rpm 3s, 750 rpm 60s; in the present invention, the curing temperature is 60°C and the time is 1h.

[0036] In the present invention, the cross-linking method of the PVA / PDMS layer prepared above is preferably ultraviolet cross-linking, and the layer is placed under a 254nm ultraviolet lamp for irradiation and cross-linking for 2 hours to obtain a wrinkled film layer.

[0037] In the present invention, the molar ratio of the two perovskite precursors is 1:1, and an appropriate amount of deionized water is added as a solvent according to the amount of the two perovskite precursors added, and the concentration of the perovskite precursor solution is preferably 0.02mol / L-0.04mol / L; in the present invention, the evaporation and crystallization method of the perovskite precursor solution is preferably a spin coating centrifugation method or a low-temperature evaporation method; the spin coating centrifugation method is operated as follows: the supernatant of the perovskite precursor solution is added dropwise to the above-prepared wrinkled part, and after standing for a period of time, it is spin-coated and thrown off with a sizing machine, and heated to evaporate and crystallize to construct a luminescent material layer; the low-temperature evaporation method is operated as follows: a trace amount of the perovskite precursor solution is added dropwise to the above-prepared wrinkled part, and heated to evaporate and crystallize to construct a luminescent material layer.

[0038] In the present invention, the standing time of the spin coating centrifugation method is preferably 2-5 min, the rotation speed is preferably 1000rpm-3000rpm, more preferably 1500rpm-2000rpm, the heating evaporation temperature is 20-60°C, more preferably 45-55°C; the evaporation temperature of the low-temperature evaporation method is 20°C-50°C, more preferably 30°C-40°C.

[0039] In the present invention, after constructing the light-emitting material layer, a layer of PDMS needs to be spin-coated to complete the encapsulation.

[0040] The following are some specific embodiments of the present invention:

[0041] Example 1

[0042] A method for preparing a fluorescent wrinkled anti-counterfeiting identification label comprises the following steps:

[0043] S1. Evenly mix PDMS and curing agent in a ratio of 50:1, evenly apply it to a clean glass sheet, set the oven temperature to 80°C and cure for 2 hours, and after curing, set the plasma cleaning machine power to 50% and the treatment time to 45 seconds to perform plasma treatment to obtain a wrinkled base layer;

[0044] S2, PVA, photocrosslinker sodium benzoate and solvent deionized water are uniformly mixed in a ratio of 47:3:250, and the mixture is dissolved at 90°C to obtain a polyvinyl alcohol solution of PVA and the photocrosslinker with a total mass volume concentration of 200 mg / ml, and the polyvinyl alcohol solution is uniformly coated on the wrinkled base layer obtained in step S1, and the oven temperature is set to 60°C for insulation and curing for 1 hour. After curing, the mixture is placed under a 254nm ultraviolet lamp for ultraviolet crosslinking for 2 hours to obtain a wrinkled film layer;

[0045] S3, cesium bromide, lead bromide and deionized water are mixed in a ratio of 6.4:11:1000, and ultrasonically decomposed for 5 minutes, and after standing for 15 minutes, the upper liquid is taken as the perovskite precursor solution, and the perovskite precursor solution is dripped onto the wrinkled film layer obtained in step S2 with a dropper until it basically covers the wrinkled film layer obtained in step S2, and after standing for 3 minutes, the film is spin-coated and dried with a glue machine at a speed of 1800 rpm, and then placed on a hot glue table at 50°C for heating to evaporate and crystallize to obtain a luminescent material layer;

[0046] S4. The support material layer, the wrinkled base layer, the wrinkled film layer and the luminescent material layer obtained in the above steps are encapsulated by PDMS to obtain a fluorescent wrinkled anti-counterfeiting identification label.

[0047] Example 2

[0048] A method for preparing a fluorescent wrinkled anti-counterfeiting identification label comprises the following steps:

[0049] S1. Evenly mix PDMS and curing agent in a ratio of 50:1, evenly apply it to a clean glass sheet, set the oven temperature to 80°C and cure for 2 hours, and after curing, set the plasma cleaning machine power to 50% and the treatment time to 45 seconds to perform plasma treatment to obtain a wrinkled base layer;

[0050] S2, PVA, photocrosslinker sodium benzoate and solvent deionized water are uniformly mixed in a ratio of 47:3:200, and the mixture is dissolved at 90°C to obtain a polyvinyl alcohol solution of PVA and the photocrosslinker with a total mass volume concentration of 250 mg / ml, and the polyvinyl alcohol solution is uniformly coated on the wrinkled base layer obtained in step S1, and the oven temperature is set to 60°C for insulation and curing for 1 hour. After curing, the mixture is placed under a 254nm ultraviolet lamp for ultraviolet crosslinking for 2 hours to obtain a wrinkled film layer;

[0051] S3, cesium bromide, lead bromide and deionized water were mixed in a ratio of 4.3:7.3:1000, and ultrasonicated for 5 minutes to make them uniformly decomposed, and after standing for 15 minutes, the upper layer of liquid was taken as the perovskite precursor solution, and 8 μL of the perovskite precursor solution was dripped onto the wrinkled film layer with a micro-liquid dispenser, and placed on a hot glue table at 40°C to heat for evaporation and crystallization to obtain a luminescent material layer;

[0052] S4. The support material layer, the wrinkled base layer, the wrinkled film layer and the luminescent material layer obtained in the above steps are encapsulated by PDMS to obtain a fluorescent wrinkled anti-counterfeiting identification label.

[0053] Example 3

[0054] A method for preparing a fluorescent wrinkled anti-counterfeiting identification label comprises the following steps:

[0055] S1. Evenly mix PDMS and curing agent in a ratio of 50:1, evenly apply it to a clean glass sheet, set the oven temperature to 80°C and cure for 2 hours, and after curing, set the plasma cleaning machine power to 50% and the treatment time to 45 seconds to perform plasma treatment to obtain a wrinkled base layer;

[0056] S2, PVA, photocrosslinker sodium benzoate and solvent deionized water are uniformly mixed in a ratio of 47:3:225, and the mixture is dissolved at 90°C to obtain a polyvinyl alcohol solution of PVA and the photocrosslinker with a total mass volume concentration of 222 mg / ml, and the polyvinyl alcohol solution is uniformly coated on the wrinkled base layer obtained in step S1, and the oven temperature is set to 60°C for insulation and curing for 1 hour. After curing, the mixture is placed under a 254nm ultraviolet lamp for ultraviolet crosslinking for 2 hours to obtain a wrinkled film layer;

[0057] S3, cesium bromide, lead bromide and deionized water were mixed in a ratio of 4.3:7.3:1000, and ultrasonicated for 5 minutes to make them uniformly decomposed, and after standing for 15 minutes, the upper liquid was taken as the perovskite precursor solution, and 4 μL of the perovskite precursor solution was dripped onto the wrinkled film layer with a micro-liquid dispenser, and placed on a hot glue table at 35°C to heat for evaporation and crystallization to obtain a luminescent material layer;

[0058] S4. The support material layer, the wrinkled base layer, the wrinkled film layer and the luminescent material layer obtained in the above steps are encapsulated by PDMS to obtain a fluorescent wrinkled anti-counterfeiting identification label.

[0059] Comparative Example 1

[0060] The difference between Comparative Example 1 and Example 1 is that the addition of PVA in step S2 is eliminated, and the remaining steps are exactly the same as those in Example 1.

[0061] Comparative Example 2

[0062] The difference between Comparative Example 2 and Example 1 is that the step of ultraviolet cross-linking for 2 hours using a 254 nm ultraviolet lamp in step S2 is eliminated, and the remaining steps are exactly the same as those in Example 1.

[0063] The fluorescent wrinkled anti-counterfeiting identification labels prepared in Examples 1-3 and Comparative Examples 1-2 were irradiated with a 365nm ultraviolet lamp, and fluorescence was shown respectively, wherein Figure 3-5 They are luminous effect diagrams of the fluorescent wrinkled anti-counterfeiting identification labels prepared in Example 132 of the present invention. It can be clearly seen that in Examples 1-3, due to the presence of PVA cross-linking, a wrinkled structure is formed, and the wrinkled structure is divided into a convex part and a concave part. In the fluorescent wrinkled anti-counterfeiting identification labels prepared in Examples 1-3, an obvious fluorescent part is generated on the concave part, forming a layer of anti-counterfeiting.

[0064] contrast Figure 7 and Figure 8 , Figure 7 and Figure 8 No wrinkle pattern was produced in either case, and only perovskite particles existed; Figure 7 The meso-perovskite particles are directly crystallized on the hydrophobic surface PDMS, so the particles are larger and do not show a random lattice distribution; Figure 8 The perovskite particles are crystallized on the uncrosslinked PVA. PVA is a hydrophilic surface, so the perovskite crystal particles are moderate, random, and randomly distributed; however, the uncrosslinked PVA cannot form a wrinkled structure with PDMS, so the perovskite distribution presents a completely random lattice, and the morphology control in the embodiment cannot be achieved.

[0065] Furthermore, Figure 6 For the present invention Figure 1 The local magnified high-definition image shows that the strong fluorescent part formed in the concave part of the fold constitutes a first layer of anti-counterfeiting of the present invention. Outside the concave part, due to the random lattice distribution of the perovskite particles, it constitutes a secondary anti-counterfeiting. Through the multi-layer anti-counterfeiting structure, in specific applications, for example, a primary comparison can be made through the concave fluorescent part to quickly screen out counterfeit products, and then the fluorescent ions randomly distributed outside the concave part can be compared again. This setting can ensure the anti-counterfeiting ability while also quickly screening out a large number of anti-counterfeiting marks that cannot be counterfeited with the concave fluorescent structure.

[0066] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fluorescent wrinkled anti-counterfeiting identification label, characterized in that: It includes a supporting material layer, a pleated base layer, a pleated film layer and a luminescent material layer; the pleated base layer is located on the upper layer of the supporting material layer, and the pleated layer is formed by curing polydimethylsiloxane; the pleated film layer is located on the upper layer of the pleated base layer, and the pleated film layer is formed by cross-linking polyvinyl alcohol; The luminescent material layer is distributed in the wrinkled film layer, and the luminescent material in the luminescent material layer is all-inorganic cesium lead halide perovskite nanocrystal.

2. The fluorescent wrinkled anti-counterfeiting identification label according to claim 1, characterized in that: The supporting material layer is a glass substrate.

3. The method for preparing the fluorescent wrinkled anti-counterfeiting identification label according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1. Evenly mix polydimethylsiloxane and curing agent, evenly apply them to a clean glass sheet, set the oven temperature to 80°C and cure for 2 hours, and perform plasma treatment after curing to obtain a wrinkled base layer; S2, uniformly mixing PVA, a photocrosslinking agent and a solvent of deionized water, dissolving them at 90°C to obtain a polyvinyl alcohol solution, uniformly coating the polyvinyl alcohol solution on the wrinkled base layer obtained in step S1, setting an oven temperature of 60°C for curing for 1 hour, and placing it under a 254nm ultraviolet lamp for ultraviolet crosslinking for 2 hours after curing to obtain a wrinkled film layer; S3, mixing cesium bromide, lead bromide and deionized water, and performing ultrasonic treatment for 5 minutes to uniformly decompose the mixed solution, and taking the upper layer of liquid as the perovskite precursor solution after standing for 15 minutes, and dropping the perovskite precursor solution on the wrinkled film layer obtained in step S2, and obtaining the luminescent material layer by spin coating centrifugation method or low-temperature evaporation method; S4. The support material layer, the wrinkled base layer, the wrinkled film layer and the luminescent material layer obtained in the above steps are encapsulated by PDMS to obtain a fluorescent wrinkled anti-counterfeiting identification label.

4. The method for preparing the fluorescent wrinkled anti-counterfeiting identification label according to claim 3, characterized in that: The mass ratio of polydimethylsiloxane to curing agent in step S1 is 50:

1.

5. The method for preparing the fluorescent wrinkled anti-counterfeiting identification label according to claim 3, characterized in that: In step S2, the photocrosslinking agent is sodium benzoate, the mass ratio of the photocrosslinking agent to polyvinyl alcohol is 3:47, and the sum of the mass volume concentrations of PVA and the photocrosslinking agent in the polyvinyl alcohol solution is 200-250 mg / ml.

6. The fluorescent wrinkled anti-counterfeiting identification label according to claim 3, characterized in that: The mass ratio of the cesium bromide, lead bromide and deionized water is 6.4:11:1000.

Images