Polymer porous membrane for fluorescent pattern transfer printing and preparation method and application thereof

Abstract

The invention belongs to the technical field of fluorescent anti-counterfeit labels, and particularly relates to a polymer porous membrane for fluorescent pattern transfer printing and a preparation method and application thereof. The polymer porous film comprises a porous film prepared by photopolymerization, the surface of the porous film is modified with at least one active functional group through ATRP (Atom Transfer Radical Polymerization) reaction in a patterning manner, and the active functional group is connected with at least one fluorescent molecule through a covalent bond. The invention further provides a fluorescent anti-counterfeit label formed by transferring the polymer porous membrane. The polymer porous membrane and the fluorescent anti-counterfeiting label prepared from the polymer porous membrane have the advantages that the preparation method is simple, the pattern designability is high, the anti-counterfeiting effect is reliable, and multiband response can be realized, so that the polymer porous membrane and the fluorescent anti-counterfeiting label prepared from the polymer porous membrane have a very good application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorescent anti-counterfeiting labels, and in particular relates to a polymer porous membrane for transferring fluorescent patterns, and a preparation method and application thereof. Background Art

[0002] The widespread spread of counterfeiting in banknotes, diplomas, tax stamps and certificates has become a serious threat to society. Therefore, efforts are being made to develop innovative anti-counterfeiting technologies to avoid counterfeiting and ensure the safety and reliability of authentic documents. Common fluorescent anti-counterfeiting labels are an anti-counterfeiting technology that uses special fluorescent inks printed on labels. This ink can emit fluorescence under ultraviolet light, showing specific text, patterns or information, thereby playing an anti-counterfeiting role. Fluorescent anti-counterfeiting labels use inks with dual invisible anti-counterfeiting properties to print hidden information such as text, patterns, numbers or liquidity numbers on the inside of the anti-counterfeiting label. This ink is invisible under ordinary lighting conditions, and the hidden information cannot be found by the naked eye or touch, but under the irradiation of specific bands of light (such as ultraviolet light), this information will appear, thereby achieving the purpose of anti-counterfeiting and greatly improving the accuracy and reliability of anti-counterfeiting. Fluorescent anti-counterfeiting labels can be customized according to customer needs, including text, patterns, colors, etc., to meet different anti-counterfeiting needs. 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 updated to meet market needs. For example, some new fluorescent anti-counterfeiting inks have longer fluorescent effect retention time and higher anti-counterfeiting performance.

[0003] As a common anti-counterfeiting technology, fluorescent anti-counterfeiting labels have many advantages but also some disadvantages. Generally speaking, inkjet-printed anti-counterfeiting materials are prepared by directly mixing photofluorescent color-changing compounds with polymer matrices. However, their limited compatibility may lead to a decline in ink quality, and the fluorescent effect of fluorescent anti-counterfeiting labels may gradually decay over time. If the ink material is of low quality or stored in poor conditions, the fluorescent effect may disappear in a short time, thus affecting the anti-counterfeiting effect. In addition, 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. Some lawless elements may imitate fluorescent anti-counterfeiting labels through technical means to deceive consumers. The identification of fluorescent anti-counterfeiting labels depends on special 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 a certain extent. The fluorescent effect under ultraviolet irradiation may be affected by ambient light, resulting in difficulty in identification. For example, in strong light or dim environment, the fluorescent effect may not be obvious enough, thus affecting the anti-counterfeiting effect.

[0004] In order to solve the above problems, it is necessary to develop new fluorescent anti-counterfeiting labels and their preparation methods in this field to increase the difficulty for criminals to imitate fluorescent anti-counterfeiting labels and make it easier for consumers to check fluorescent anti-counterfeiting labels to determine the authenticity of products. Summary of the invention

[0005] In order to solve the problems of the prior art, the present invention provides a polymer porous membrane for fluorescent pattern transfer and a preparation method and use thereof.

[0006] A polymer porous membrane for fluorescent pattern transfer, comprising a porous film made by photopolymerization, wherein the surface of the porous film is pattern-modified with at least one active functional group by ATRP reaction, and the active functional group is connected with at least one fluorescent molecule by a covalent bond;

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

[0008] 4-56 parts of the first acrylic acid ester monomer,

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

[0010] 8-32 parts of cross-linking agent,

[0011] Photoinitiator 0.25-2 parts,

[0012] Inhibitor 0.25-2 parts,

[0013] Solvent 20-80 parts.

[0014] Priority, the first acrylic acid ester monomer is selected from methacrylic acid ester monomers or acrylic acid ester monomers without a methyl group, and the methacrylic acid ester monomer is selected from at least one of hydroxyethyl methacrylate, methyl methacrylate, 2-ethylhexyl methacrylate, polyethylene glycol methacrylate, and 3-sulfonic acid propyl ester potassium salt;

[0015] And / or, the second acrylic acid ester monomer is selected from a methacrylic acid ester monomer containing ATRP initiator 2-bromoisobutyl or an acrylic acid ester monomer without a methyl group, and the methacrylic acid ester monomer is selected from at least one of 2-(2-bromoisobutylpropoxy)ethyl methacrylate, 2-bromo-3-methoxy-2-methylpropyl 2-methyl-2-acrylate, 2-bromo-3-methoxy-2-methyl-3-oxopropyl 2-methyl-2-acrylate and 2-bromo-3-butoxy-2-methyl-3-oxopropyl 2-methyl-2-acrylate;

[0016] And / or, the cross-linking agent is at least one selected from 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 IRGACURE369;

[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-tetramethylpiperidinyl nitroxide free radical;

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

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

[0021] 16 parts of hydroxyethyl methacrylate,

[0022] 8 parts of 2-(2-bromoisobutylpropoxy)ethyl 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 comprises immersing the porous film in a reaction solution and then irradiating it with light;

[0029] The reaction solution includes the following components:

[0030] 0.5-2 mole parts of the third acrylic ester monomer containing an active functional group,

[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] Among them, the ratio of mole parts, weight parts and volume parts is:

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

[0036] Priority, the active functional group is selected from NHS group or maleimide group

[0037] The third acrylate monomer is selected from maleimide acrylate monomers, the maleimide acrylate monomer is selected from at least one of 2-propylene-1-yl-2,5-dihydro-2,5-diketo-1H-pyrrole-1-acetate, N-(2-acryloyloxyethyl) maleimide, N-(2-acryloyloxypropyl) maleimide, 1H-pyrrole-1-acetic acid 2,5-dihydro-2,5-diketo-2-propylene ester, and the acrylic acid-N-succinimide ester monomer is selected from at least one of N-acryloyloxysuccinimide, 3-butenoic acid, 2,5-dioxo-1-pyrrolidyl ester, and 4-pentenoic acid N-hydroxysuccinimide ester;

[0038] 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 a thiol group is obtained by reacting an amino-active dye molecule with cystamine hydrochloride and then using TCEP to reduce the disulfide bond, and the dye molecule having an amino group is selected from rhodamine B-NH 2 、Cy3-NH 2 、Cy5-NH 2 、Cy5.5-NH 2 FITC-NH 2 Alexa Fluor-NH 2 、Texas red-NH 2 At least one of;

[0039] And / or, the catalyst is selected from Ir(ppy) 3 , Ir(piq)2, and iron tetraphenylporphyrin (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, TBP tributylphosphine (TBP);

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

[0042] Priority, the reaction solution includes the following components:

[0043] 1 mol part of a third acrylic ester monomer containing an active functional group,

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

[0045] 1.2 parts by weight of ascorbic acid,

[0046] N-methylpyrrolidone 0.2 parts by volume,

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

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

[0049] Step 1, preparing the prepolymerization solution, and forming a liquid film from the prepolymerization solution;

[0050] Step 2, performing patterned exposure on the liquid film and performing photopolymerization reaction to obtain the porous film having a patterned shape;

[0051] Step 3, immersing the porous film in a reaction solution made of a third acrylic ester monomer containing an active functional group, a catalyst, and a reducing agent, and performing patterned exposure; this step is performed at least once, and at least one active functional group is patterned and modified on the porous film through an ATRP reaction;

[0052] Step 4, immersing the porous film treated in step 3 into a solution containing fluorescent molecules for reaction, and obtaining the porous film; this step is performed at least once, and at least one fluorescent molecule is modified on the porous film.

[0053] Priority, in step 1, the liquid film is formed between the maskless photolithography screen and the glass substrate, and the glass substrate is subjected to the following modification treatment: the glass substrate is activated by concentrated alkali and concentrated acid, and the surface is subjected to double bond modification treatment using a silane coupling agent; the silane coupling agent is selected from 3-(trimethoxysilyl)propyl methacrylate;

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

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

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

[0057] In the present invention, the ATRP reaction refers to an atom transfer radical polymerization reaction. The "first acrylate monomer", "second acrylate monomer" and "third acrylate monomer" all refer to acrylate monomers, and the "first solvent" and "second solvent" all refer to solvents. The "first", "second" and "third" herein only serve to distinguish different terms, and do not indicate any priority or ranking, and do not have a limiting effect on the chemical structure, physicochemical properties, etc. of the reagents.

[0058] In the present invention, the fluorescent molecules are purchased commercially or synthesized in the laboratory. The fluorescent molecules containing amino groups are chemically stable and most of them can be purchased commercially. The fluorescent molecules containing sulfhydryl groups are sensitive to oxygen and can be synthesized in the laboratory. The synthetic route is to use fluorescent molecules containing amino groups (such as FITC) to react with cystamine, or to use fluorescent molecules containing amino groups and disulfides containing NHS groups (such as PEG). n＝7The detailed information of some amino-containing or amino-active fluorescent molecules is as follows:

[0059]

[0060]

[0061] The present invention has developed a new type of anti-counterfeiting technology, which uses maskless photolithography technology to graft different types of fluorescent molecules on the polymer film formed by photocuring on the glass surface in a regionally selective and density-adjustable manner, and uses the different responses of different fluorescent molecules to light of each band to achieve further encryption of pattern information. First, the present invention first forms a polymer porous film on the glass surface through blue light cross-linking curing and phase separation induction, and based on the 2-bromoisobutyryl bromide group on the surface of the porous film, the blue light-induced ATRP reaction is carried out on the pore surface to achieve grafting of (methyl) acrylate monomers containing different active functional groups (such as NHS groups with amino activity, maleimide groups with thiol activity, etc.) on the polymer main chain, thereby further achieving the chemical introduction of different dyes on the surface by a covalent method. This efficient preparation scheme for fluorescent patterns has high stability and high resolution, and the minimum pixel size of the precision maskless photolithography machine is 80 microns. At the same time, the present invention proposes an innovative transfer strategy for fluorescent patterns. By simply sticking and tearing the commercially available adhesive pressure-sensitive tape on the surface of the prepared polymer porous film, a fluorescent label with an imperceptible film can be obtained. The transfer process is repeated on the surface of the same dye-modified film to prepare high-quality and repeatable transfer preparation of fluorescent pattern labels. The multi-band fluorescent label provided by the present invention does not rely on professional fluorescence microscopy equipment. A strong and clearly identifiable fluorescent pattern can be observed by irradiating the sample surface with a simple commercial banknote detector black light flashlight, and part of the fluorescence can be intercepted by a commercial cheap filter to reveal hidden information, thereby achieving multiple anti-counterfeiting 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 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 repeatedly transfer the adhesive backing pressure-sensitive tape, which makes the preparation cost of the fluorescent anti-counterfeiting label low and the process flow simple;

[0065] 3. The inspection equipment of the fluorescent anti-counterfeiting label of the present invention is simple and convenient for consumers to use; on the other hand, it can also respond to multiple bands through the combination of commercial cheap filters, which is difficult for criminals to imitate.

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

[0067] Obviously, according to the above contents of the present invention, in accordance with common technical knowledge and customary means in the art, without departing from the above basic technical ideas of the present invention, other various forms of modification, replacement or change may be made.

[0068] The above contents of the present invention are further described in detail below through specific implementation methods in the form of embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above contents of the present invention belong to the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0071] Figure 3 This is an example diagram of the transfer preparation of the fluorescent anti-counterfeiting label in Example 2;

[0072] Figure 4 This is an example diagram of reading the multi-band fluorescent pattern of the fluorescent anti-counterfeiting label prepared in Example 2. DETAILED DESCRIPTION

[0073] In the following examples and experimental examples, 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 that can be used for fluorescent pattern transfer provided in this embodiment is prepared according to the following method:

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

[0077] 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 were mixed in a specific ratio, and 0.4 mg of photoinitiator phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and 0.2 mg of inhibitor 4-methoxyphenol were added and mixed to form a prepolymer solution. After the glass substrate was activated by immersion treatment in NaOH solution (1M) for 1 h and HCL solution (1M) for 0.5 h, the surface was immersed in a silane coupling agent (3-(trimethoxymethylsilyl) propyl methacrylate) (40 vol% dissolved in ethanol) for 4-6 h for double bond modification.

[0078] For example Figure 1 As shown, 30-100 μL of prepolymer solution is dripped onto the maskless lithography screen, and a 15 μm thick polyimide film is placed on each side of the solution. The pre-modified glass substrate is positioned on the solution and the film, and bubbles are removed to form a uniform liquid film about 15 μm thick. Subsequently, the pre-designed printing pattern is sliced ​​by the software and imported into the maskless lithography system, and projected onto the printing platform in the form of 405 nm blue light. After the exposure is completed, the glass substrate and the porous film are carefully separated, and the unreacted monomers and porogens are rinsed with anhydrous ethanol and dried with an air gun. A porous film is obtained.

[0079] In other embodiments, the HEMA in the above steps can be replaced by other (meth) acrylate monomers, including but not limited to: methyl methacrylate, 2-ethylhexyl methacrylate, polyethylene glycol methacrylate, methacrylate 3-sulfonic acid propyl ester potassium salt. BrMA can be replaced by other second acrylate monomers containing 2-bromoisobutyryl bromide groups, including but not limited to: 2-(2-bromoisobutylpropoxy)ethyl methacrylate, 2-bromo-3-methoxy-2-methylpropyl 2-methyl-2-acrylate, 2-bromo-3-methoxy-2-methyl-3-oxopropyl 2-methyl-2-acrylate, 2-bromo-3-butoxy-2-methyl-3-oxopropyl 2-methyl-2-acrylate. The cross-linking agent can be replaced by other commonly used cross-linking agents, including but not limited to: ethylene glycol dimethacrylate, trimethylolpropane triacrylate, N-hydroxymethyl acrylamide, zinc acrylate, multifunctional aziridine, divinylbenzene. The photoinitiator can be replaced by other commonly used photoinitiators, including but not limited to: phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide, benzophenone, 4-chlorobenzophenone, benzoin dimethyl ether, 2-isopropylthioxanthone, 1-hydroxy-cyclohexyl-phenyl ketone, IRGACURE369. The inhibitor can be replaced by other commonly used inhibitors, including but not limited to: benzaldehyde, di-tert-butyl-p-cresol, p-toluenesulfonamide, hydroquinone, phenothiazine, 2,2,6,6-tetramethylpiperidinyl nitroxide free radical. Cyclohexanol and n-decanol can be replaced by other organic solvents, including but not limited to: isopentanol, n-hexanol, cyclohexanol, n-octanol, sec-octanol, n-nonanol, n-decanol, and dodecanol.

[0080] 2. Maskless lithography introduces multi-band fluorescent patterns into polymer porous membranes

[0081] This step can be repeated multiple times to introduce a variety of fluorescent molecules with different pattern modifications, thereby achieving the formation of multi-band fluorescent patterns, such as Figure 2 As shown, the three-dimensional model designed by 3Ds Max software is exported to .stl format, sliced ​​by the software, recognized by the maskless lithography machine and converted into a layer-by-layer exposure pattern. After the polymer porous membrane prepared in the above steps is exposed in the exposure area by light-triggered ATRP reaction, the porous film is immersed in a fluorescent dye solution containing corresponding characteristic reaction chemical groups. Through one-step functional monomer grafting and one-step dye reaction, multiple fluorescent molecules are independently anchored in specific areas, thereby realizing the introduction of multi-band fluorescent patterns in the polymer porous membrane.

[0082] As an example, this embodiment provides a sequential pattern modification of Rhodamine B and Cy5-NH 2 Preferred dye options:

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

[0084] First, in a glove box, 1 mmol of ethyl 2-(1,3,3a,4,7,7a-hexahydro-1,3-diketo-4,7-epoxy-2H-isoindol-2-yl)acrylate and 1 mg of Ir(ppy) were added. 3 , 200μL NMP (N-methylpyrrolidone), 1.2mg ascorbic acid, 1mL DMF (N,N-dimethylformamide) are mixed in a vial, 100-200μL of the prepolymer solution is taken with a syringe and dropped on the maskless photolithography screen, the prepared porous film with ATRP reaction activity is covered on the prepolymer solution to make it completely immersed, the bubbles are discharged and positioned to the pre-designed pattern position, and then the pre-designed printing pattern is introduced into the photolithography system after software slicing, and projected onto the printing platform in the form of 405nm blue light. After the exposure is completed, the porous film is carefully separated from the maskless photolithography screen with a carving knife, and the unreacted monomers are rinsed with anhydrous ethanol and dried with an air gun. After cleaning, the porous film is completely immersed in DMSO and heated to 135℃ for 4h deprotection treatment. Then, place it in a 50 mL sealed centrifuge tube, add 0.2 μg / mL aqueous solution of a fluorescent dye with a thiol unit (for example, in this embodiment, rhodamine B dye with a thiol end group is used as an example) until the polymer film is completely immersed, stir at room temperature for 24 hours and then take out the film, place it in another 50 mL sealed centrifuge tube again, add anhydrous ethanol until the polymer film is completely immersed to clean it, wash out the unreacted dye, then take out the film and dry it with an air gun.

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

[0086]

[0087] The preparation method thereof can be referred to 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, isothiocyanate rhodamine B (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 using TCEP in water solvent to obtain the product.

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

[0089] First, 1 mmol of acrylic acid-N-succinimidyl ester monomer and 1 mg of Ir(ppy) were added in a glove box. 3 , 200μL NMP, 1.2mg ascorbic acid, 1mL DMF are mixed in a vial, 100-200μL of the prepolymer solution is taken with a syringe and dripped on the maskless photolithography screen, the prepared polymer film with ATRP reaction activity is covered on the prepolymer solution to make it completely immersed, the bubbles are discharged and positioned to the pre-designed pattern position, and then the pre-designed printing pattern is introduced into the photolithography system after software slicing, and projected onto the printing platform in the form of 405nm blue light. After the exposure is completed, the substrate is carefully separated with a carving knife, and the unreacted monomers are rinsed off with anhydrous ethanol and dried with an air gun. After cleaning, the polymer film is placed in a 50mL sealed centrifuge tube, and 0.05μg / mL of a dye molecule with an amino group (Cy5-NH in this embodiment) is added. 2 The film was taken out after stirring at room temperature for 24 hours and placed in another 50 mL sealed centrifuge tube. Anhydrous ethanol was added to completely immerse the polymer film for cleaning. After the unreacted dye was cleaned, the film was taken out and dried 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, tetraphenylporphyrin iron (Fe(III)-TPP). Ascorbic acid can be replaced by other reducing agents, including but not limited to sodium ascorbate and sodium formaldehyde sulfoxylate. NMP and DMF can be replaced by other organic solvents, including but not limited to toluene, anisole, chlorobenzene, dioxane, cyclohexanone and acetonitrile.

[0091] Thus, the present application prepares 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 Embodiment 1 is further subjected to transfer of fluorescent patterns to prepare fluorescent anti-counterfeiting labels, and the fluorescent patterns of the fluorescent anti-counterfeiting labels are read.

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

[0095] Use Deli invisible tape (pressure-sensitive adhesive tape) to adhere to the polymer porous membrane prepared in Example 1 and then slowly tear it off, so that a film with a fluorescent pattern is left on the adhesive layer of the tape, and the original information on the front of the tape will not be affected. In other embodiments, there is no brand restriction for the pressure-sensitive adhesive tape, and the material of the pressure-sensitive adhesive tape includes but is not limited to PET, PVC and other highly transparent or frosted tapes. Therefore, the tape can be further processed into a fluorescent anti-counterfeiting label suitable for various application scenarios.

[0096] Regarding the reading of the fluorescence pattern, Figure 4 As shown, first, the design of the multi-band fluorescent pattern is to utilize the sequential excitation of multiple fluorescent molecules to generate multi-band fluorescent emission with 360nm ultraviolet excitation light. For example, in this embodiment, the ATRP catalyst Ir(ppy) 3 During the photolithography process, strong green fluorescence visible under UV excitation will be left in the exposed area, which can further excite the subsequently grafted fluorescent molecules such as Cy5-NH 2 , through multi-step area selective exposure, layer by layer, the pattern can be observed under different filters. A specific example is that under the irradiation of the ultraviolet flashlight, the green pattern fluorescence clearly visible to the naked eye is revealed, and then through the commercial cheap 650nm wavelength filter, the green fluorescence is intercepted, revealing the hidden Cy5-NH 2 Red fluorescence of the dye.

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

Claims

1. A polymer porous membrane for fluorescent pattern transfer, characterized in that: A porous film made of photopolymerization, wherein the surface of the porous film is patterned and modified with at least one active functional group through an ATRP reaction, and the active functional group is connected with at least one fluorescent molecule through a covalent bond; The prepolymer solution used to prepare the porous membrane includes the following components in parts by weight: 4-56 parts of the first acrylic acid ester monomer, 1-16 parts of a second acrylic ester monomer containing a 2-bromoisobutyryl bromide group, 8-32 parts of cross-linking agent, Photoinitiator 0.25-2 parts, Inhibitor 0.25-2 parts, Solvent 20-80 parts.

2. The polymer porous membrane according to claim 1, characterized in that: The first acrylic acid ester monomer is selected from a methacrylic acid ester monomer or an acrylic acid ester monomer not containing a methyl group, and the methacrylic acid ester monomer is selected from at least one of hydroxyethyl methacrylate, methyl methacrylate, 2-ethylhexyl methacrylate, polyethylene glycol methacrylate, and 3-sulfonic acid propyl ester potassium salt of methacrylate; And / or, the second acrylic acid ester monomer is selected from a methacrylic acid ester monomer containing ATRP initiator 2-bromoisobutyl or an acrylic acid ester monomer without a methyl group, and the methacrylic acid ester monomer is selected from at least one of 2-(2-bromoisobutylpropoxy)ethyl methacrylate, 2-bromo-3-methoxy-2-methylpropyl 2-methyl-2-acrylate, 2-bromo-3-methoxy-2-methyl-3-oxopropyl 2-methyl-2-acrylate and 2-bromo-3-butoxy-2-methyl-3-oxopropyl 2-methyl-2-acrylate; And / or, the cross-linking agent is at least one selected from 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 IRGACURE369; 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-tetramethylpiperidinyl nitroxide free radical; And / or, the first solvent is selected from at least one of isopentanol, 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)ethyl 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 film in a reaction solution and then irradiating it with light; The reaction solution includes the following components: 0.5-2 mole parts of the third acrylic ester monomer containing an active functional group, 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; Among them, the ratio of mole parts, weight parts and volume parts is: 1 mole part: 1 weight part: 1 volume part = 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 group or maleimide group The third acrylate monomer is selected from maleimide acrylate monomers, the maleimide acrylate monomer is selected from at least one of 2-propylene-1-yl-2,5-dihydro-2,5-diketo-1H-pyrrole-1-acetate, N-(2-acryloyloxyethyl) maleimide, N-(2-acryloyloxypropyl) maleimide, 1H-pyrrole-1-acetic acid 2,5-dihydro-2,5-diketo-2-propylene ester, and the acrylic acid-N-succinimide ester monomer is selected from at least one of N-acryloyloxysuccinimide, 3-butenoic acid, 2,5-dioxo-1-pyrrolidyl 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 Texas red-SH, and 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 porous polymer membrane according to claim 4 or 5, characterized in that: The reaction solution includes the following components: 1 mol part of a third acrylic ester monomer containing an active functional group, Ir(ppy)3 1 part by weight, 1.2 parts by weight of ascorbic acid, N-methylpyrrolidone 0.2 parts by volume, N,N-dimethylformamide 1 part by volume.

7. The method for preparing a porous polymer membrane according to any one of claims 1 to 6, characterized in that: The steps include: Step 1, preparing the prepolymerization solution, and forming the prepolymerization solution into a liquid film; Step 2, performing patterned exposure on the liquid film and performing photopolymerization reaction to obtain the porous film having a patterned shape; Step 3, immersing the porous film in a reaction solution made of a third acrylic ester monomer containing an active functional group, a catalyst, and a reducing agent, and performing patterned exposure; this step is performed at least once, and at least one active functional group is patterned and modified on the porous film through an ATRP reaction; Step 4, immersing the porous film treated in step 3 into a solution containing fluorescent molecules for reaction, and obtaining the porous film; this step is performed at least once, and at least one fluorescent molecule is modified on the porous film.

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, and the glass substrate is modified as follows: the glass substrate is activated by concentrated alkali and concentrated acid, and the surface is double-bond modified by using a silane coupling agent; the silane coupling agent is selected from 3-(trimethoxysilyl)propyl methacrylate; And / or, in step 2 to step 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 to 6 in preparing fluorescent anti-counterfeiting labels.

10. A fluorescent anti-counterfeiting label, characterized in that: The invention is made by bonding a pressure-sensitive adhesive tape with the polymer porous film according to any one of claims 1 to 6 and then tearing them off.

Images