Polymeric porous membranes for fluorescent pattern transfer and methods of making and using the same

Abstract

The present application belongs to the technical field of fluorescent anti-counterfeiting label, and particularly relates to a polymer porous film for fluorescent pattern transfer and a preparation method and application thereof. The polymer porous film comprises a porous film prepared by photopolymerization, and at least one active functional group is patterned and modified on the surface of the porous film through ATRP reaction, and at least one fluorescent molecule is connected to the active functional group through a covalent bond. The present application further provides a fluorescent anti-counterfeiting label transferred by the above polymer porous film. The polymer porous film and the fluorescent anti-counterfeiting label prepared therefrom have the advantages of simple preparation method, strong designability of patterns, reliable anti-counterfeiting effect and multi-waveband response, and have a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent anti-counterfeiting label technology, specifically relating to a polymer porous membrane for fluorescent pattern transfer, its preparation method, and its uses. Background Technology

[0002] Counterfeiting is widespread in banknotes, diplomas, tax stamps, and certificates, posing a serious threat to society. Therefore, there is a strong push to develop innovative anti-counterfeiting technologies to prevent counterfeiting and ensure the security and reliability of genuine documents. A common anti-counterfeiting label is a special fluorescent ink printed on the label. This ink fluoresces under ultraviolet light, displaying specific text, patterns, or information, thus serving as an anti-counterfeiting measure. Fluorescent anti-counterfeiting labels use ink with dual invisible anti-counterfeiting properties, printing the necessary information, such as text, patterns, numbers, or serial numbers, inside the label. This ink is invisible under ordinary light conditions; the hidden information cannot be found with the naked eye or touch. However, under specific wavelengths of light (such as ultraviolet light), this information becomes visible, achieving the purpose of anti-counterfeiting and greatly improving the accuracy and reliability of anti-counterfeiting measures. Fluorescent anti-counterfeiting labels can be customized according to customer needs, including text, patterns, and colors, to meet different anti-counterfeiting requirements. As one of the mature anti-counterfeiting technologies on the market, fluorescent anti-counterfeiting labels have been widely used and recognized. With the continuous development of anti-counterfeiting technology, fluorescent anti-counterfeiting labels are also constantly being updated to adapt to market demands. For example, some new fluorescent anti-counterfeiting inks have a longer fluorescence retention time and higher anti-counterfeiting performance.

[0003] Fluorescent anti-counterfeiting labels, as a common anti-counterfeiting technology, have many advantages but also some disadvantages. Generally, inkjet-printed anti-counterfeiting materials are prepared by directly mixing photofluorescent compounds with a polymer matrix. However, their limited compatibility may lead to a decline in ink quality, and the fluorescent effect of fluorescent anti-counterfeiting labels may gradually fade over time. If the ink material is of poor quality or stored under poor conditions, the fluorescent effect may disappear in a short period of time, thus affecting the anti-counterfeiting effect. Furthermore, most reported anti-counterfeiting inks operate in a single-channel response mode. Although the production of fluorescent anti-counterfeiting labels requires certain technology and equipment, its technical threshold is still relatively low compared to other high-end anti-counterfeiting technologies. The ink materials used in fluorescent anti-counterfeiting labels are relatively easy to obtain in the market, and some criminals may use technical means to counterfeit fluorescent anti-counterfeiting labels, thereby deceiving consumers. The identification of fluorescent anti-counterfeiting labels relies on specialized detection instruments such as ultraviolet lamps. If consumers do not have these devices, they cannot directly verify the authenticity of the product, which limits its scope of use to some extent. The fluorescent effect under ultraviolet light may be affected by ambient light, making identification difficult. For example, the fluorescence effect may not be obvious enough in bright light or dim light, thus affecting the anti-counterfeiting effect.

[0004] To address these issues, it is necessary to develop new compositions and preparation methods for fluorescent anti-counterfeiting labels, thereby increasing the difficulty for counterfeiters to replicate them and making it easier for consumers to verify the authenticity of products. Summary of the Invention

[0005] To address the problems of existing technologies, this invention provides a polymer porous membrane for fluorescent pattern transfer, its preparation method, and its applications.

[0006] A polymer porous membrane for fluorescent pattern transfer includes a porous film made by photopolymerization, wherein the surface of the porous film is patterned and modified with at least one active functional group by ATRP reaction, and the active functional group is covalently linked to at least one fluorescent molecule.

[0007] The prepolymer solution used to prepare the porous membrane comprises the following components in parts by weight:

[0008] 4-56 parts of the first acrylate monomer,

[0009] 1-16 parts of a second acrylate monomer containing a 2-bromoisobutyryl bromide group

[0010] 8-32 parts of crosslinking agent

[0011] Photoinitiator 0.25-2 parts,

[0012] Polymerization inhibitor 0.25-2 parts,

[0013] Solvent 20-80 parts.

[0014] Priority is given to the first acrylate monomer selected from methacrylate monomers or acrylate monomers without methyl groups, wherein the methacrylate monomer is selected from at least one of hydroxyethyl methacrylate, methyl methacrylate, 2-ethylhexyl methacrylate, polyethylene glycol methacrylate, and potassium propyl methacrylate 3-sulfonate.

[0015] And / or, the second acrylate monomer is selected from methacrylate monomers containing the ATRP initiator 2-bromoisobutyl or acrylate monomers without methyl groups, wherein the methacrylate monomer is selected from at least one of 2-(2-bromoisobutylpropoxy)methacrylate, 2-bromo-3-methoxy-2-methylpropyl-2-meth-2-acrylate, 2-bromo-3-methoxy-2-methyl-3-oxopropyl-2-meth-2-acrylate, and 2-bromo-3-butoxy-2-methyl-3-oxopropyl-2-meth-2-acrylate;

[0016] And / or, the crosslinking agent is selected from at least one of ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, and divinylbenzene;

[0017] And / or, the photoinitiator is selected from at least one of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzophenone, 4-chlorobenzophenone, benzoin dimethyl ether, 2-isopropylthioxanthone, 1-hydroxy-cyclohexyl-phenyl ketone, and IRGACURE 369;

[0018] And / or, the polymerization inhibitor is selected from at least one of 4-methoxyphenol, benzaldehyde, di-tert-butyl-p-cresol, p-toluenesulfonamide, hydroquinone, phenothiazine, and 2,2,6,6-tetramethylpiperidine nitroxide radical;

[0019] And / or, the first solvent is selected from at least one of isoamyl alcohol, n-hexanol, cyclohexanol, n-octanol, sec-octanol, n-nonanol, n-decanol, and dodecanol.

[0020] Priority is given to the prepolymer solution of the porous membrane, which comprises the following components in parts by weight:

[0021] 16 parts of hydroxyethyl methacrylate

[0022] 8 parts of 2-(2-bromoisobutylpropoxy)methacrylate

[0023] 16 parts of ethylene glycol dimethacrylate

[0024] 0.4 parts of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide

[0025] 0.2 parts of 4-methoxyphenol

[0026] 36 parts of cyclohexanol

[0027] 24 parts of n-decyl alcohol.

[0028] Priority, the ATRP reaction process includes immersing the porous membrane in a reaction solution and then irradiating it with light;

[0029] The reaction solution comprises the following components in the following proportions:

[0030] 0.5-2 molar parts of third acrylate monomers containing active functional groups

[0031] 0.5-2 parts by weight of catalyst

[0032] 0.5-2 parts by weight of reducing agent

[0033] 1-2 parts by volume of the second solvent;

[0034] The ratios of molar parts, weight parts, and volume parts are as follows:

[0035] 1 mole: 1 weight: 1 volume = 1 mmol: 1 mg: 1 ml.

[0036] Priority is given to the active functional group selected from NHS groups or maleimide groups.

[0037] The third acrylate monomer is selected from maleimide acrylate monomers, which are selected from at least one of 2-propen-1-yl-2,5-dihydro-2,5-dione-1H-pyrrole-1-acetate, N-(2-acryloyloxyethyl)maleimide, N-(2-acryloyloxypropyl)maleimide, and 1H-pyrrole-1-acetate 2,5-dihydro-2,5-dione-2-propenyl ester. The acrylate-N-succinimide monomer is selected from at least one of N-acryloyloxysuccinimide, 3-butenoic acid, 2,5-dioxo-1-pyrrolidine ester, and 4-pentenoic acid N-hydroxysuccinimide ester.

[0038] The fluorescent molecule is selected from dye molecules having thiol or amino groups. The dye molecule having thiol is selected from at least one of Rhodamine B-SH, Rhodamine 6G-SH, Cy3-SH, Cy5-SH, Cy5.5-SH, FITC-SH, Alexa Fluor-SH, and Texasred-SH. The dye molecule having thiol is obtained by reacting an amino reactive dye molecule with cystamine hydrochloride and then reducing the disulfide bond using TCEP. The dye molecule having amino groups is selected from at least one of Rhodamine B-NH2, Cy3-NH2, Cy5-NH2, Cy5.5-NH2, FITC-NH2, Alexa Fluor-NH2, and Texas red-NH2.

[0039] And / or, the catalyst is selected from at least one of Ir(ppy)3, Ir(piq)2, and tetraphenylporphyrin iron (Fe(Ⅲ)-TPP);

[0040] And / or, the reducing agent is selected from at least one of ascorbic acid, TPP triphenylphosphonate, TEP tris(2-hydroxyethyl) phosphate, and TBP tributylphosphide (TBP);

[0041] And / or, the second solvent is selected from at least one of N-methylpyrrolidone and N,N-dimethylformamide.

[0042] Priority is given to the reaction solution comprising the following components in the following proportions:

[0043] 1 molar part of a third acrylate monomer containing an active functional group

[0044] Ir(ppy)3 1 part by weight

[0045] Ascorbic acid 1.2 parts by weight

[0046] 0.2 parts by volume of N-methylpyrrolidone

[0047] 1 part by volume of N,N-dimethylformamide.

[0048] The present invention also provides a method for preparing the above-mentioned polymer porous membrane, comprising the following steps:

[0049] Step 1: Prepare the prepolymer solution and form a liquid film from the prepolymer solution;

[0050] Step 2: The liquid film is patterned by exposure and photopolymerization to obtain the porous film with a patterned shape;

[0051] Step 3: Immerse the porous film in a reaction solution containing a third acrylate monomer, a catalyst, and a reducing agent with active functional groups for patterned exposure; this step is performed at least once, and at least one active functional group is patterned and modified on the porous film by ATRP reaction.

[0052] Step 4: Immerse the porous film treated in step 3 into a solution containing fluorescent molecules for reaction, and obtain the final product; this step is performed at least once to modify the porous film with at least one fluorescent molecule.

[0053] Priority is given to the liquid film formed between the maskless photolithography screen and the glass substrate in step 1. The glass substrate is modified as follows: the glass substrate is activated by concentrated alkali and concentrated acid, and the surface is modified with double bonds using a silane coupling agent. The silane coupling agent is selected from 3-(trimethoxysilyl)propyl methacrylate.

[0054] And / or, in steps 2 to 3, the patterned exposure is achieved by a maskless lithography system.

[0055] The present invention also provides the use of the above-mentioned polymer porous membrane in the preparation of fluorescent anti-counterfeiting labels.

[0056] The present invention also provides a fluorescent anti-counterfeiting label, which is made by bonding pressure-sensitive adhesive tape to the above-mentioned polymer porous film and then peeling it off.

[0057] In this invention, the ATRP reaction refers to atom transfer radical polymerization. "First acrylate monomer," "second acrylate monomer," and "third acrylate monomer" all refer to acrylate monomers, and "first solvent" and "second solvent" all refer to solvents. The terms "first," "second," and "third" are merely used to distinguish different terms and do not indicate any priority or order, nor do they limit the chemical structure or physicochemical properties of the reagents.

[0058] In this invention, the fluorescent molecules are either commercially available or synthesized in the laboratory. Amino-containing fluorescent molecules are chemically stable, and most are commercially available. Thiol-containing fluorescent molecules are sensitive to oxygen and can be synthesized in the laboratory by reacting amino-containing reactive fluorescent molecules (such as FITC) with cystamine, or by reacting amino-containing fluorescent molecules with disulfides containing NHS groups (such as PEG). n＝7 Obtained by NHS Ester Disulfide reaction. Specific information on some amino-containing or amino-active fluorescent molecules is as follows:

[0059]

[0060]

[0061] This invention develops a novel anti-counterfeiting technology. Utilizing maskless photolithography, different types of fluorescent molecules are selectively and tunably grafted onto a polymer film formed by photocuring on a glass surface. The different responses of these fluorescent molecules to various wavelengths of light further encrypt the pattern information. First, a porous polymer film is formed on the glass surface through blue light crosslinking curing and phase separation induction. Based on the 2-bromoisobutyryl bromide groups on the surface of this porous film, a blue light-initiated ATRP reaction is performed on the pore surface to graft (meth)acrylate monomers containing different active functional groups (such as amino-active NHS groups and thiol-active maleimide groups) onto the polymer backbone. This allows for the further covalent chemical introduction of different dyes onto the surface. This highly efficient fluorescent pattern preparation method exhibits high stability and high resolution, with a minimum pixel size of 80 micrometers on the maskless photolithography machine. Simultaneously, this invention proposes an innovative transfer strategy for fluorescent patterns. By simply adhering and peeling commercially available adhesive pressure-sensitive tape onto the surface of a prepared polymer porous membrane, a fluorescent label retaining a barely perceptible thin film can be obtained. This transfer process can be repeated on the same dye-modified film surface, achieving high-quality and reproducible transfer preparation of fluorescent pattern labels. The multi-band fluorescent label provided by this invention does not rely on professional fluorescence microscopy equipment. A strong and clearly discernible fluorescent pattern can be observed by illuminating the sample surface with a simple commercially available black flashlight. Furthermore, some fluorescence can be blocked by commercially available inexpensive filters, revealing hidden information and achieving multiple anti-counterfeiting features of the fluorescent pattern.

[0062] In summary, the technical solution of the present invention has the following beneficial technical effects:

[0063] 1. The fluorescent anti-counterfeiting label pattern produced has the characteristics of high stability and high resolution;

[0064] 2. In the preparation process of the fluorescent anti-counterfeiting label of the present invention, the polymer porous membrane can be repeatedly transferred to the backing pressure-sensitive tape, which makes the preparation cost of the fluorescent anti-counterfeiting label low and the process simple.

[0065] 3. The testing equipment for the fluorescent anti-counterfeiting label of the present invention is simple and easy for consumers to use; on the other hand, the combination of commercially available inexpensive filters enables multi-band response, making it difficult for criminals to counterfeit.

[0066] Therefore, the polymer porous membrane and the fluorescent anti-counterfeiting label made therefrom provided by the present invention have great application prospects.

[0067] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0068] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0069] Figure 1 This is an example diagram illustrating the design and fabrication of the porous polymer film pattern in Example 1;

[0070] Figure 2 This is an example diagram illustrating the design and fabrication of gradient and channel-independent fluorescence patterns in Example 1;

[0071] Figure 3 This is an example image of the transfer printing process used to prepare fluorescent anti-counterfeiting labels in Example 2;

[0072] Figure 4 This is an example image showing the reading of the multi-band fluorescent pattern of the fluorescent anti-counterfeiting label prepared in Example 2. Detailed Implementation

[0073] In the following examples and experimental cases, reagents and raw materials not specifically described are all commercially available products.

[0074] Example 1: Polymer porous membrane for fluorescent pattern transfer

[0075] The polymer porous membrane for fluorescent pattern transfer provided in this embodiment is prepared according to the following method:

[0076] 1. Fabrication of patterned hydrophilic polymer porous membranes with ATRP reactivity using maskless photolithography.

[0077] A prepolymer solution was prepared by mixing 16 mg of hydroxyethyl methacrylate (HEMA), 8 mg of 2-(2-bromoisobutylpropoxy)ethyl methacrylate (BrMA), 16 mg of ethylene glycol dimethacrylate (EDMA), 36 mg of cyclohexanol, and 24 mg of n-decanol in a specific ratio, adding 0.4 mg of photoinitiator phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and 0.2 mg of polymerization inhibitor 4-methoxyphenol. After immersion activation treatment in NaOH solution (1M) for 1 h and HCl solution (1M) for 0.5 h, the glass substrate was then subjected to double bond modification by immersion treatment in a silane coupling agent (propyl 3-(trimethoxysilyl)methacrylate) (40 vol% soluble in ethanol) for 4-6 h.

[0078] For example, Figure 1 As shown, 30-100 μL of prepolymer solution is dropped onto a maskless photolithography screen, and a 15 μm thick polyimide film is placed on each side of the solution. A pre-modified glass substrate is then positioned on top of the solution and films, and air bubbles are removed to form a uniform liquid film of approximately 15 μm thickness between them. Subsequently, the pre-designed printing pattern is sliced ​​using software and imported into the maskless photolithography system, then projected onto the printing platform as 405 nm blue light. After exposure, the glass substrate and porous film are carefully separated, and unreacted monomers and pore-forming agents are washed away with anhydrous ethanol and dried with an air gun. This yields the porous film.

[0079] In other embodiments, HEMA in the above steps can be replaced with other (meth)acrylate monomers, including but not limited to: methyl methacrylate, 2-ethylhexyl methacrylate, polyethylene glycol methacrylate, and potassium propyl 3-sulfonate methacrylate. BrMA can be replaced with other second acrylate monomers containing a 2-bromoisobutyryl bromide group, including but not limited to: ethyl 2-(2-bromoisobutylpropoxy)methacrylate, 2-bromo-3-methoxy-2-methylpropyl-2-meth-2-acrylate, 2-bromo-3-methoxy-2-methyl-3-oxopropyl-2-meth-2-acrylate, and 2-bromo-3-butoxy-2-methyl-3-oxopropyl-2-methyl-2-acrylate. The crosslinking agent can be replaced with other commonly used crosslinking agents, including but not limited to: ethylene glycol dimethacrylate, trimethylolpropane triacrylate, N-hydroxymethylacrylamide, zinc acrylate, polyfunctional aziridine, and divinylbenzene. The photoinitiator can be replaced with other commonly used photoinitiators, including but not limited to: phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzophenone, 4-chlorobenzophenone, benzoin dimethyl ether, 2-isopropylthioxanthone, 1-hydroxy-cyclohexyl-phenyl ketone, and IRGACURE 369. The polymerization inhibitor can be replaced with other commonly used polymerization inhibitors, including but not limited to: benzaldehyde, di-tert-butyl-p-cresol, p-toluenesulfonamide, hydroquinone, phenothiazine, and 2,2,6,6-tetramethylpiperidine nitroxide radical. Cyclohexanol and n-decyl alcohol can be replaced with other organic solvents, including but not limited to: isoamyl alcohol, n-hexanol, cyclohexanol, n-octanol, sec-octanol, n-nonanol, n-decyl alcohol, and dodecanol.

[0080] 2. Maskless photolithography introduces multi-band fluorescence patterns into the polymer porous film.

[0081] This step can be repeated multiple times to introduce various patterned fluorescent molecules, thereby achieving the formation of multi-band fluorescent patterns, such as... Figure 2As shown, the 3D model designed by 3Ds Max software is exported as a .stl file, sliced ​​by the software, and then identified and converted into a layer-by-layer exposure pattern by a maskless lithography machine. The polymer porous film prepared by the above steps is then used to introduce functional monomers into the exposure area through a photo-initiated ATRP reaction. The porous film is then immersed in a fluorescent dye solution containing corresponding characteristic reactive chemical groups. Through a one-step functional monomer grafting and one-step dye reaction, multiple fluorescent molecules are independently anchored in specific areas, thereby introducing multi-band fluorescent patterns into the polymer porous film.

[0082] As an example, this embodiment provides a preferred scheme for sequentially patterning and modifying Rhodamine B and Cy5-NH2 dyes:

[0083] (1) Introducing fluorescent dye molecules with thiol units via maleimide-thiol characteristic reaction

[0084] First, in a glove box, 1 mmol of ethyl 2-(1,3,3a,4,7,7a-hexahydro-1,3-dione-4,7-epoxy-2H-isoindol-2-yl)acrylate, 1 mg of Ir(ppy)3, 200 μL of NMP (N-methylpyrrolidone), 1.2 mg of ascorbic acid, and 1 mL of LDMF (N,N-dimethylformamide) were mixed and placed in a vial. Using a syringe, 100-200 μL of this prepolymer solution was dropped onto a maskless photolithography screen. The prepared porous film with ATRP reactivity was then placed on top of the prepolymer solution, ensuring complete immersion. Air bubbles were removed, and the film was positioned at the pre-designed pattern location. The pre-designed printing pattern was then sliced ​​using software and imported into the photolithography system, projected onto the printing platform as 405 nm blue light. After exposure, the porous film was carefully separated from the maskless photolithography screen using a scriber. Unreacted monomers were washed away with anhydrous ethanol, and the film was dried with an air gun. After cleaning, the porous membrane was completely immersed in DMSO and heated to 135°C for 4 hours for deprotection. Then, it was placed in a 50 mL sealed centrifuge tube, and an aqueous solution of a 0.2 μg / mL fluorescent dye with thiol units (e.g., Rhodamine B dye with thiol end groups in this example) was added until the polymer membrane was completely submerged. After stirring at room temperature for 24 hours, the membrane was removed and placed in another 50 mL sealed centrifuge tube. Anhydrous ethanol was added until the polymer membrane was completely submerged to clean it and remove any unreacted dye. The membrane was then removed and dried using an air gun.

[0085] In this embodiment, the structure of the mercapto-terminated rhodamine B dye used is as follows:

[0086]

[0087] The preparation method can be referred to in the literature (Greg T. Hermanson, Chapter 10-Fluorescent Probes, Editor(s): Greg T. Hermanson, Bioconjugate Techniques (Third Edition), Academic Press, 2013, Pages 395-463, ISBN 9780123822390). Specifically, rhodamine B isothiocyanate (purchased from Macklin Reagent, CAS No.: 36877-69-7) is reacted with cystamine hydrochloride in DMF solvent for 24 hours, and then the disulfide bond is reduced in aqueous solvent using TCEP to obtain the product.

[0088] (2) Introducing fluorescent dye molecules with amino groups through the NHS ester-amino characteristic reaction.

[0089] First, in a glove box, 1 mmol of acrylate-N-succinimide monomer, 1 mg of Ir(ppy)3, 200 μL of NMP, 1.2 mg of ascorbic acid, and 1 mL of DMF were mixed and placed in a vial. Using a syringe, 100-200 μL of this prepolymer solution was dropped onto a maskless photolithography screen. The prepared ATRP-reactive polymer film was then placed on the prepolymer solution to completely immerse it. Air bubbles were removed, and the film was positioned at the pre-designed pattern location. Subsequently, the pre-designed printing pattern was sliced ​​using software and imported into the photolithography system, then projected onto the printing platform as 405 nm blue light. After exposure, the substrate was carefully separated with a scriber, unreacted monomers were rinsed off with anhydrous ethanol, and the substrate was dried with an air gun. After cleaning, place the polymer film in a 50mL sealed centrifuge tube, add 0.05μg / mL of dye molecule with amino groups (Cy5-NH2 dye is used as an example in this example) DMF solution until the polymer film is completely submerged, stir at room temperature for 24h, remove the film, place it in another 50mL sealed centrifuge tube, add anhydrous ethanol until the polymer film is completely submerged and cleaned, remove the unreacted dye, and dry it with an air gun.

[0090] In the above steps, Ir(ppy)3 can be replaced with other ATRP catalysts, including but not limited to: Ir(ppy)3, Ir(piq)2, and tetraphenylporphyrin iron (Fe(Ⅲ)-TPP). Ascorbic acid can be replaced with other reducing agents, including but not limited to: sodium ascorbate and sodium formaldehyde sulfoxylate. NMP and DMF can be replaced with other organic solvents, including but not limited to: toluene, anisole, chlorobenzene, dioxane, cyclohexanone, and acetonitrile.

[0091] Thus, this application yields a polymer porous membrane that can be used for fluorescent pattern transfer.

[0092] Example 2: Fluorescent Anti-counterfeiting Label

[0093] In this embodiment, the polymer porous membrane prepared in Example 1 is further subjected to fluorescent pattern transfer to make a fluorescent anti-counterfeiting label, and the fluorescent pattern of the fluorescent anti-counterfeiting label is read.

[0094] The specific process is as follows: Figure 3 As shown, it includes the following steps:

[0095] After bonding the polymer porous membrane prepared in Example 1 with Deli invisible adhesive tape (pressure-sensitive adhesive tape), it is slowly peeled off, leaving a thin film with a fluorescent pattern on the adhesive backing layer of the tape without affecting the original information on the front of the tape. In other embodiments, the pressure-sensitive adhesive tape is not limited to any brand, and the material of the pressure-sensitive adhesive tape includes, but is not limited to, high-transparency or frosted materials such as PET and PVC. Therefore, this tape can be further processed into fluorescent anti-counterfeiting labels suitable for various application scenarios.

[0096] Regarding the reading of fluorescent patterns, such as Figure 4 As shown, the design of the multi-band fluorescence pattern utilizes the sequential excitation of multiple fluorescent molecules to generate multi-band fluorescence emission with 360nm ultraviolet excitation light. For example, in this embodiment, the ATRP catalyst Ir(ppy)3 leaves a strong green fluorescence visible under ultraviolet excitation in the exposed area during photolithography. This fluorescence can further excite subsequently grafted fluorescent molecules such as Cy5-NH2. By layering patterns through multi-step regional selective exposure, different patterns can be observed under different filters. Specifically, under ultraviolet flashlight illumination, a clearly visible green pattern fluorescence is displayed, while passing through a commercially available, inexpensive 650nm wavelength filter blocks the green fluorescence, revealing the hidden red fluorescence of the Cy5-NH2 dye.

[0097] As can be seen from the above embodiments, the polymer porous membrane and the fluorescent anti-counterfeiting label made therefrom provided by the present invention have the advantages of simple preparation method, strong pattern designability, reliable anti-counterfeiting effect, and ability to achieve multi-band response, and have good application prospects.

Claims

1. A polymer porous membrane for fluorescent pattern transfer, characterized in that, The invention includes a porous film made by photopolymerization, wherein the surface of the porous film is patterned and modified with at least one active functional group by ATRP reaction, and the active functional group is covalently linked to at least one fluorescent molecule. The prepolymer solution used to prepare the porous membrane comprises the following components in parts by weight: 4-56 parts of the first acrylate monomer, 1-16 parts of a second acrylate monomer containing a 2-bromoisobutyryl bromide group 8-32 parts of crosslinking agent Photoinitiator 0.25-2 parts, Polymerization inhibitor 0.25-2 parts, Solvent 20-80 parts; The first acrylate monomer is selected from methacrylate monomers or acrylate monomers without methyl groups, wherein the methacrylate monomer is selected from at least one of hydroxyethyl methacrylate, methyl methacrylate, 2-ethylhexyl methacrylate, polyethylene glycol methacrylate, and potassium propyl methacrylate 3-sulfonate. The second acrylate monomer is selected from methacrylate monomers containing the ATRP initiator 2-bromoisobutyl or acrylate monomers without methyl groups, wherein the methacrylate monomer is selected from at least one of 2-(2-bromoisobutylpropoxy)methacrylate, 2-bromo-3-methoxy-2-methylpropyl-2-meth-2-acrylate, 2-bromo-3-methoxy-2-methyl-3-oxopropyl-2-meth-2-acrylate, and 2-bromo-3-butoxy-2-methyl-3-oxopropyl-2-methyl-2-acrylate.

2. The polymer porous membrane according to claim 1, characterized in that: The crosslinking agent is selected from at least one of ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, and divinylbenzene; And / or, the photoinitiator is selected from at least one of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzophenone, 4-chlorobenzophenone, benzoin dimethyl ether, 2-isopropylthioxanthone, 1-hydroxy-cyclohexyl-phenyl ketone, and IRGACURE 369; And / or, the polymerization inhibitor is selected from at least one of 4-methoxyphenol, benzaldehyde, di-tert-butyl-p-cresol, p-toluenesulfonamide, hydroquinone, phenothiazine, and 2,2,6,6-tetramethylpiperidine nitroxide radical; And / or, the first solvent is selected from at least one of isoamyl alcohol, n-hexanol, cyclohexanol, n-octanol, sec-octanol, n-nonanol, n-decanol, and dodecanol.

3. The polymer porous membrane according to claim 1 or 2, characterized in that: The prepolymer solution of the porous membrane comprises the following components in parts by weight: 16 parts of hydroxyethyl methacrylate 8 parts of 2-(2-bromoisobutylpropoxy)methacrylate 16 parts of ethylene glycol dimethacrylate 0.4 parts of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide 0.2 parts of 4-methoxyphenol 36 parts of cyclohexanol 24 parts of n-decyl alcohol.

4. The polymer porous membrane according to claim 1, characterized in that: The ATRP reaction process includes immersing the porous membrane in a reaction solution and then irradiating it with light. The reaction solution comprises the following components in the following proportions: 0.5-2 molar parts of third acrylate monomers containing active functional groups 0.5-2 parts by weight of catalyst 0.5-2 parts by weight of reducing agent 1-2 parts by volume of the second solvent; The ratios of molar parts, weight parts, and volume parts are as follows: 1 mole: 1 weight: 1 volume = 1 mmol: 1 mg: 1 ml.

5. The polymer porous membrane according to claim 4, characterized in that: The active functional group is selected from NHS groups or maleimide groups. The third acrylate monomer is selected from maleimide acrylate monomers, which are selected from at least one of 2-propen-1-yl-2,5-dihydro-2,5-dione-1H-pyrrole-1-acetate, N-(2-acryloyloxyethyl)maleimide, N-(2-acryloyloxypropyl)maleimide, and 1H-pyrrole-1-acetate 2,5-dihydro-2,5-dione-2-propenyl ester. The acrylate-N-succinimide monomer is selected from at least one of N-acryloyloxysuccinimide, 3-butenoic acid, 2,5-dioxo-1-pyrrolidine ester, and 4-pentenoic acid N-hydroxysuccinimide ester. The fluorescent molecule is selected from dye molecules having a thiol group or an amino group. The dye molecule having a thiol group is selected from at least one of Rhodamine B-SH, Rhodamine 6G-SH, Cy3-SH, Cy5-SH, Cy5.5-SH, FITC-SH, Alexa Fluor-SH, and Texasred-SH. The dye molecule having an amino group is selected from at least one of Rhodamine B-NH2, Cy3-NH2, Cy5-NH2, Cy5.5-NH2, FITC-NH2, Alexa Fluor-NH2, and Texas red-NH2. And / or, the catalyst is selected from at least one of Ir(ppy)3, Ir(piq)2, and tetraphenylporphyrin iron (Fe(Ⅲ)-TPP); And / or, the reducing agent is selected from at least one of ascorbic acid, TPP triphenylphosphonate, TEP tris(2-hydroxyethyl) phosphate, and TBP tributylphosphine; And / or, the second solvent is selected from at least one of N-methylpyrrolidone and N,N-dimethylformamide.

6. The polymer porous membrane according to claim 4 or 5, characterized in that: The reaction solution comprises the following components in the following proportions: 1 molar part of a third acrylate monomer containing an active functional group Ir(ppy)3 1 part by weight Ascorbic acid 1.2 parts by weight 0.2 parts by volume of N-methylpyrrolidone 1 part by volume of N,N-dimethylformamide.

7. The method for preparing the polymer porous membrane according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Prepare the prepolymer solution and form a liquid film from the prepolymer solution; Step 2: The liquid film is patterned by exposure and photopolymerization to obtain the porous film with a patterned shape; Step 3: Immerse the porous film in a reaction solution containing a third acrylate monomer, a catalyst, and a reducing agent with active functional groups for patterned exposure; this step is performed at least once, and at least one active functional group is patterned and modified on the porous film by ATRP reaction. Step 4: Immerse the porous film treated in step 3 into a solution containing fluorescent molecules for reaction, and obtain the final product; this step is performed at least once to modify the porous film with at least one fluorescent molecule.

8. The preparation method according to claim 7, characterized in that: In step 1, the liquid film is formed between the maskless photolithography screen and the glass substrate. The glass substrate undergoes the following modification treatment: the glass substrate is activated by concentrated alkali and concentrated acid, and the surface is modified with a silane coupling agent to modify the double bonds. The silane coupling agent is selected from propyl 3-(trimethoxysilyl)methacrylate. And / or, in steps 2 to 3, the patterned exposure is achieved by a maskless lithography system.

9. Use of the polymer porous membrane according to any one of claims 1-6 in the preparation of fluorescent anti-counterfeiting labels.

10. A fluorescent anti-counterfeiting label, characterized in that, It is made by bonding pressure-sensitive adhesive tape to the polymer porous membrane described in any one of claims 1-6 and then peeling it off.

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