High viscosity fluoropolymer solutions and their use

Abstract

This invention belongs to the field of responsive material production technology, specifically relating to a high-viscosity fluoropolymer solution and its applications. The preparation method of the high-viscosity fluoropolymer solution is as follows: (meth)acrylate naphthyl ester, fluorinated methacrylate, and vinylcarbazole are dissolved in a solvent and stirred to obtain a clear and transparent solution. Then, an initiator is added, and the mixture is heated to 60-90℃ under magnetic stirring for 16-24 hours to polymerize. After the reaction is completed, a transparent high-viscosity polymer solution with a viscosity range of 800-8000 Pa·s is obtained. After the high-viscosity fluoropolymer solution forms a film on the substrate, it forms an anti-counterfeiting coating that can be stimulated by ultraviolet light and trifluoroacetic acid, exhibiting excellent multi-stimulus responsiveness. The preparation method of this anti-counterfeiting coating is simple, has good film-forming properties, long service life, and low cost. It can be industrially produced and provides dual anti-counterfeiting capabilities, showing great application prospects in anti-counterfeiting, information encryption, and other fields.

Description

Technical Field

[0001] This invention belongs to the field of responsive material production technology, specifically relating to a high-viscosity fluoropolymer solution and its applications. Background Technology

[0002] Common watermark anti-counterfeiting technologies not only require complex processes and cumbersome anti-counterfeiting procedures, but are also easily copied, making them difficult to achieve effective anti-counterfeiting goals. Optical anti-counterfeiting technologies, on the other hand, have attracted widespread attention in the anti-counterfeiting field due to their advantages such as convenient design, good visibility, low cost, and strong mass production capabilities. Currently, optical anti-counterfeiting materials mainly include structural color anti-counterfeiting materials, liquid crystal anti-counterfeiting materials, and fluorescent anti-counterfeiting materials. However, anti-counterfeiting and information encryption modes based on single optical phenomena have limitations in terms of reliability and information density. Therefore, combining anti-counterfeiting materials with different stimulus responses has become a research hotspot in recent years. Although some composite materials combining multiple stimulus responses have emerged in recent years, which can effectively increase information density and anti-counterfeiting dimensions, problems such as high manufacturing costs, complex manufacturing processes, and short service life still exist.

[0003] Patent CN108424482B discloses a multi-responsive dendritic polymer containing spiropyran and its preparation method. First, polyester and caprolactone undergo ring-opening to obtain dendritic polycaprolactone. Then, it reacts with dibromoisobutyryl bromide and triethylamine to obtain a dendritic macromolecular initiator. Next, it reacts with tert-butyl methacrylate to obtain HPs-Star-PCL-b-PtbMA. After hydrolysis, the product undergoes esterification with hydroxyspiropyran to obtain HPs-Star-PCL-b-PMAA-SP. Self-assembly yields micelles exhibiting both photoresponsive and pH-responsive properties. However, the high cost and complex synthesis process of spiropyran hinder its industrial application. Furthermore, the tightly packed structure of spiropyran in the solid state, coupled with the need for a certain free volume for isomerization and ring-opening, creates a contradiction that makes it difficult for solid-state spiropyran to undergo ring-opening under external stimuli such as ultraviolet light and acids, resulting in slow or even no color change.

[0004] CN113788972B discloses a multi-response color-changing anti-counterfeiting film. This film consists of a three-layer structure: the top and bottom layers are formed by curing a pre-solidified liquid composed of polymer monomers and a curing agent; the middle layer is a photonic crystal layer formed by the self-assembly of fluorescent colloidal particles. The fluorescent colloidal particles are obtained by loading quantum dots onto colloidal microspheres and then coating them with an outer shell. Under ultraviolet light, this color-changing anti-counterfeiting film exhibits fluorescent color; after a certain degree of stretching, it produces a visible structural color change; and after the stretching is removed, it returns to its initial shape and color. Compared to single-structural-color anti-counterfeiting and single-fluorescence anti-counterfeiting, this film possesses multi-response color-changing characteristics, achieving synergistic anti-counterfeiting through photonic crystal structural color and quantum dot fluorescence, thus enhancing the anti-counterfeiting level and showing broad application prospects in the anti-counterfeiting field. However, the cumbersome multi-layer film-forming technology of photonic crystals is not conducive to their industrial application. Furthermore, prolonged ultraviolet irradiation can damage the film structure and affect its lifespan. Summary of the Invention

[0005] To address the existing problems, this invention provides a high-viscosity fluoropolymer solution and its application. After the high-viscosity fluoropolymer solution is film-formed on a substrate, an anti-counterfeiting coating is formed. It can withstand stimulation from ultraviolet light and trifluoroacetic acid, exhibiting excellent multi-stimulus responsiveness. The preparation method of this anti-counterfeiting coating is simple, has good film-forming properties, long service life, and low cost. It can be industrially produced and provides dual anti-counterfeiting capabilities, showing great application prospects in anti-counterfeiting, information encryption, and other fields.

[0006] The novel fluoropolymer prepared by this invention exhibits excellent photoresponse as the naphthol in its structure undergoes a photo-Fries rearrangement reaction under ultraviolet light stimulation, resulting in a colorless coating turning blue under trifluoroacetic acid stimulation. Furthermore, the color changes from light blue to colorless under ammonia stimulation. Repeated operations consistently demonstrate rapid stimulus responsiveness. The technical solution of this invention is as follows:

[0007] A high-viscosity fluoropolymer solution is prepared as follows: Naphthalene (meth)acrylate, fluorinated methacrylate, and vinylcarbazole are dissolved in solvent A and stirred to obtain a clear and transparent solution. Then, an initiator is added, and the mixture is heated to 60-90℃ under magnetic stirring for 16-24 hours to polymerize. After the reaction is completed, a transparent high-viscosity polymer solution with a viscosity range of 800-8000 Pa·s is obtained.

[0008] Preferably, the fluorinated methacrylate is one of trifluoroethyl methacrylate, tetrafluoropropyl methacrylate, hexafluorobutyl methacrylate, octafluoropentyl methacrylate, dodecafluoroheptyl methacrylate, and perfluorooctyl methacrylate.

[0009] Preferably, the preparation of (meth)acrylate naphthyl ester is as follows: first, add naphthol, triethylamine and anhydrous tetrahydrofuran, and then add (meth)acryloyl chloride dropwise while stirring under ice-water bath conditions. After the addition is complete, remove the ice-water bath and react at room temperature for 19-30 hours. After the reaction is complete, filter to obtain a transparent liquid, evaporate the solvent by rotary evaporation to obtain a white solid, and then obtain (meth)acrylate naphthyl ester after post-treatment.

[0010] More preferably, the molar ratio of naphthol to triethylamine is 1:1 to 3, the molar ratio of naphthol to (meth)acryloyl chloride is 1:1 to 1.5, and the amount of tetrahydrofuran is 50-70 wt%.

[0011] More preferably, the monomer comprises 2-20 wt% naphthyl (meth)acrylate, 30-60% fluorinated methacrylate, 2-30 wt% vinylcarbazole, 0-50 wt% solvent A1, and 0.01-10% initiator by mass of total monomers.

[0012] More preferably, the post-treatment is as follows: the white solid is dissolved in solvent B, washed with deionized water, saturated sodium bicarbonate, and saturated brine, dried over anhydrous magnesium sulfate, and the solvent is removed to obtain the target product (meth)acrylate naphthyl ester. Solvent B is ethyl acetate or other solvents.

[0013] Preferably, the initiator is one of azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), and tert-butyl peroxypentanoate (TBPPI).

[0014] Preferably, solvent A is one of N,N-dimethylformamide (DMF), butyl acetate, ethyl acetate, and dimethyl sulfoxide (DMSO).

[0015] The application of the above-mentioned high-viscosity fluoropolymer solution in the field of dual anti-counterfeiting.

[0016] A high-viscosity polymer solution is applied to a substrate to form a film, which is then used to obtain an anti-counterfeiting coating.

[0017] Preferably, the specific preparation method of the anti-counterfeiting coating is as follows: a high-viscosity polymer solution is dissolved in solvent C to prepare a polymer solution with a concentration of 0.5-10 wt%, stirred to form a homogeneous transparent solution, and applied to the substrate at room temperature by spin coating, dip coating, or casting, followed by vacuum drying to obtain the anti-counterfeiting coating. Solvent C is a solvent such as tetrahydrofuran, butyl acetate, or N,N-dimethylformamide.

[0018] More preferably, the spin coating speed is 1000-3000 r / min and the spin coating time is 30-90 s.

[0019] More preferably, the substrate is immersed in a homogeneous transparent solution for 10-60 minutes (until complete immersion). After immersion, the substrate is dried at 40-80°C, and the anti-counterfeiting coating is completed.

[0020] More preferably, the substrate is pretreated before use to remove impurities from its surface. Even more preferably, the substrate is immersed in acetone, ethanol, and water respectively for ultrasonic treatment for 20-30 minutes, and then dried in an oven at 60-80°C.

[0021] Preferably, spin coating is suitable for substrates such as PDMS, glass, and silicon wafers, while dip-dyeing is suitable for textile fibers such as fabrics.

[0022] The synthesis reaction formula of the polymer of the present invention is as follows:

[0023]

[0024] R1 is a hydrogen atom or a methyl group; Rf is trifluoroethyl, tetrafluoropropyl, hexafluorobutyl, octafluoropentyl, dodecafluoroheptyl, or perfluorooctyl; x is 5-20, y is 5-40, and z is 50-300.

[0025] Photoresponse stimulation mechanism:

[0026]

[0027] The photo-Fries rearrangement reaction of naphthyl groups in polymers is a free radical mechanism. First, the phenol ester molecule is photoexcited under ultraviolet light. The excited phenol ester is homolytically cleaved into a pair of phenol and acyl free radicals in solvent or solid phase. Then, the acyl free radicals couple with the phenol free radicals from the ortho or para position and undergo tautomerism to obtain the product hydroxy aromatic ketone.

[0028] Mechanism of acid response to stimulation:

[0029]

[0030] Because the carbazole group in the structure of fluoropolymers is a basic functional group, under the stimulation of acidic components (TFA, trifluoroacetic acid), the N atom of the carbazole group is protonated to form a salt structure, and the color changes from colorless to blue-green. When the basic components (such as ammonia, triethylamine, etc.) continue to stimulate, the ammonium salt structure becomes N atoms, completing the deprotonation reaction and restoring the original colorless state.

[0031] The preparation method of the fluorinated methacrylic acid ester in this invention is simple and the cost is significantly lower compared to stimuli-responsive functional groups such as spiropyran and azo. Furthermore, the naphthol group exhibits excellent photostimulation responsiveness, undergoing a photo-Fries rearrangement reaction under 254 nm ultraviolet light to yield a product with a new emission band at 475 nm. By adjusting the ultraviolet light intensity, different gradient fluorescence patterns can be generated. N-vinylcarbazole (NVC), as an important class of organic heterocyclic small molecules, possesses excellent photoelectric properties, consistent with the characteristics of other organic optoelectronic smart materials, and exhibits good intramolecular electron transfer capabilities. Its excellent thermal stability makes it significant and valuable in the preparation of optoelectronic materials, widely used in liquid crystal display materials. Moreover, NVC is low-cost and can be mass-produced. Fluoropolymers, due to the high electronegativity and small atomic radius of fluorine atoms, possess excellent acid and alkali resistance, corrosion resistance, and ultraviolet resistance. Therefore, the application of fluorinated methacrylic acid esters to stimulus-responsive systems is beneficial. In this process, after the polymer forms a film, fluorine atoms migrate to the film surface through self-migration. Since the CF bond energy reaches 485.6 kJ / mol, which is higher than the UV light energy, it protects the coating and prevents the decomposition of ester groups in the coating. Once the ester groups decompose, the naphthyl groups will fall off from the polymer structure, affecting the subsequent photostimulation response and service life. However, fluorinated acrylates are very easy to polymerize, but if the fluorinated chain is long and the degree of polymerization is high, the crystallinity will also increase, causing the polymer to precipitate from the solution, affecting subsequent processing and use. On the other hand, if a monomer with a short fluorinated chain is selected, its UV resistance will decrease. Based on this background, vinylcarbazole and naphthyl groups with large space volume are selected. The large space volume will destroy the crystallinity of the long fluorinated chain, allowing the polymer to dissolve in the liquid and form a film quickly. At the same time, the two groups have excellent photostimulation and acid stimulation response, meeting the requirements for anti-counterfeiting and UV resistance.

[0032] This invention provides a high-viscosity fluoropolymer solution for practical application. Combining the resin polymer's good film-forming, easy-processing, and industrial-scale characteristics, a novel fluoropolymer based on naphthol, carbazole, and fluorine-containing functional groups is obtained, exhibiting excellent light and acid stimuli responsiveness and UV resistance. The preparation method of this invention is simple, easy to operate, has good film-forming properties, long service life, and low cost, and can be industrialized. It can also provide dual anti-counterfeiting features, showing great application prospects in anti-counterfeiting, information encryption, and other fields. Attached Figure Description

[0033] Figure 1 The NMR structure characterization image of naphthyl methacrylate prepared in Example 1;

[0034] Figure 2 Infrared characterization image of naphthyl methacrylate prepared in Example 1;

[0035] Figure 3The 1H NMR spectrum of the fluorinated copolymer obtained in Example 1;

[0036] Figure 4 The UV-Vis spectrum of the fluoropolymer solution in Example 1 is shown below.

[0037] Figure 5 NMR fluorine spectrum of the fluoropolymer prepared in Example 2;

[0038] Figure 6 Stimulus response changes of the fluoropolymer solution prepared in Example 2;

[0039] Figure 7 This is a schematic diagram of the anti-counterfeiting coating of Example 6 before and after ultraviolet light irradiation through a mask;

[0040] Figure 8 This is a schematic diagram of the anti-counterfeiting coating mask of Example 7 before and after TFA vapor stimulation;

[0041] Figure 9 Here are SEM images of the fabric before and after dyeing in Example 8;

[0042] Figure 10 Infrared characterization images of fluoropolymers were prepared for Examples 1-5;

[0043] Figure 11 These are schematic diagrams of contact angle measurements for Example 3 and Comparative Example 3.

[0044] Figure 12 Curves showing the change in gloss of the films prepared in Example 3 and Comparative Example 3 with UV aging time. Detailed Implementation

[0045] The technical solutions in this embodiment will be described in detail below, but the described embodiments are only some embodiments of the present invention and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this application.

[0046] Example 1

[0047] (1) Preparation method of naphthyl methacrylate:

[0048] First, naphthol (0.1 mol), triethylamine (0.11 mol), and anhydrous tetrahydrofuran (40 mL) were added to a single-necked flask. Methacryl chloride (0.13 mol) was added dropwise while stirring under ice-water bath conditions. After the addition was complete, the ice-water bath was removed, and the reaction was allowed to proceed at room temperature for 24 hours. After the reaction was complete, a transparent liquid was obtained by filtration. The solvent was removed by rotary evaporation to obtain a white solid. The crude product was dissolved in ethyl acetate and washed with deionized water, saturated sodium bicarbonate, and saturated brine, respectively. After drying with anhydrous magnesium sulfate, the target product, naphthyl methacrylate monomer, was obtained after solvent removal. The product was characterized by NMR. Figure 1 As shown, 1 ¹H NMR (400MHz, CDCl₃) δ 7.97–7.85 (m, 2H), 7.78 (t, J = 10.5 Hz, 1H), 7.62–7.46 (m, 3H), 7.34 (d, J = 7.5 Hz, 1H), 6.57 (s, 1H), 5.96–5.84 (m, 1H), 2.21 (s, 3H); The obtained naphthyl methacrylate was characterized by infrared spectroscopy, as follows: Figure 2 As shown in the figure, 3047cm -1 The peak at 1733 cm⁻¹ represents the stretching vibration of the CH bond. -1 The absorption peak for the carbonyl group is 1636 cm⁻¹. -1 The absorption peak is the CH bond on the benzene ring, combined with Figure 1 The structure of naphthyl methacrylate was finally determined by proton nuclear magnetic resonance spectroscopy.

[0049] (2) Preparation method of high viscosity fluoropolymer solution:

[0050] 10g of naphthalene methacrylate, 30g of trifluoroethyl methacrylate, and 8g of vinylcarbazole obtained in step 1 were dissolved in 40g of butyl acetate. The solution was stirred and dissolved to obtain a clear and transparent solution. Then, 0.38g of initiator AIBN was added, and the mixture was heated to 70℃ and polymerized for 24h under magnetic stirring. After the reaction was completed, a transparent high-viscosity polymer solution with a viscosity of 5000 Pa·s was obtained.

[0051] A small amount of the high-viscosity polymer solution from Example 1 was taken out, precipitated in anhydrous ethanol, filtered, and dried to obtain a white powder. The powder was characterized by 1H NMR spectroscopy using deuterated chloroform as a solvent, and the following was obtained: Figure 3 As shown.

[0052] After taking 1 mL of the high-viscosity fluoropolymer solution prepared in Example 1 and diluting it to 10 mL with butyl acetate, a white transparent liquid was obtained. The solution was continuously irradiated with ultraviolet light, and the ultraviolet-visible spectrum was analyzed. Figure 4 As shown, the absorbance of the solution at 375 nm increased continuously with the extension of irradiation time. This is because under ultraviolet light irradiation, the naphthyl ester group in the solution rearranged to produce a hydroxy aromatic ketone structure.

[0053] Example 2

[0054] (1) Preparation method of naphthyl methacrylate:

[0055] First, naphthol (0.2 mol), triethylamine (0.26 mol), and anhydrous tetrahydrofuran (80 mL) were added to a single-necked flask. Under ice-water bath conditions, methacryloyl chloride (0.30 mol) was added dropwise while stirring. After the addition was complete, the ice-water bath was removed, and the reaction was carried out at room temperature for 20 h. After the reaction was completed, a transparent liquid was obtained by filtration. The solvent was removed by rotary evaporation to obtain a white solid. The crude product was dissolved in ethyl acetate, washed with deionized water, saturated sodium bicarbonate, and saturated brine, respectively, and dried over anhydrous magnesium sulfate. After removing the solvent, the target product, naphthyl methacrylate monomer, was obtained.

[0056] (2) Preparation method of high viscosity fluoropolymer solution:

[0057] First, 15g of naphthalene methacrylate, 30g of dodecafluoroheptyl methacrylate, and 15g of vinylcarbazole obtained above were dissolved in 50g of butyl acetate. The solution was stirred and dissolved to obtain a clear and transparent solution. Then, 0.48g of initiator AIBN was added, and the mixture was heated to 70℃ and polymerized for 24h under magnetic stirring. After the reaction was completed, a transparent high-viscosity polymer solution with a viscosity of 6150 Pa·s was obtained.

[0058] A small amount of the high-viscosity polymer solution from Example 2 was taken out, precipitated in anhydrous ethanol, filtered, and dried to obtain a white powder. The powder was characterized by nuclear magnetic resonance fluorine spectroscopy. Figure 5 As shown.

[0059] Take 0.5 mL of the high-viscosity fluoropolymer solution prepared in Example 2, dilute it to 5 mL with butyl acetate, and a white transparent liquid is obtained. Adding 0.5 mL of TFA to the solution immediately changes the solution from colorless to blue. Adding triethylamine changes the solution from blue to colorless. Figure 6 As shown, the high-viscosity fluoropolymer solution provided by the present invention has good cyclic stimulation response characteristics.

[0060] Example 3

[0061] (1) Preparation method of naphthyl acrylate:

[0062] Naphthol (0.15 mol), triethylamine (0.18 mol), and anhydrous tetrahydrofuran (60 mL) were added to a single-necked flask. Acryloyl chloride (0.18 mol) was added dropwise while stirring under ice-water bath conditions. After the addition was complete, the ice-water bath was removed, and the reaction was carried out at room temperature for 24 h. After the reaction was completed, a transparent liquid was obtained by filtration. The solvent was removed by rotary evaporation to obtain a white solid. The crude product was dissolved in ethyl acetate, washed with deionized water, saturated sodium bicarbonate, and saturated brine, and dried over anhydrous magnesium sulfate. After removing the solvent, the target product, naphthyl acrylate monomer, was obtained. (2) Preparation method of high viscosity fluoropolymer solution:

[0063] 20g of naphthalene acrylate, 40g of hexafluorobutyl methacrylate, and 15g of vinylcarbazole obtained above were dissolved in 60g of DMF and stirred to obtain a clear and transparent solution. Then, 1.3g of initiator BPO was added, and the mixture was heated to 80℃ and polymerized for 24h under magnetic stirring. After the reaction was completed, a transparent high-viscosity polymer solution with a viscosity of 5800 Pa·s was obtained.

[0064] Example 4

[0065] (1) Preparation method of naphthyl methacrylate:

[0066] First, naphthol (0.3 mol), triethylamine (0.33 mol), and anhydrous tetrahydrofuran (140 mL) were added to a single-necked flask. Under ice-water bath conditions, methacryloyl chloride (0.36 mol) was added dropwise while stirring. After the addition was complete, the ice-water bath was removed, and the reaction was carried out at room temperature for 20 h. After the reaction was completed, a transparent liquid was obtained by filtration. The solvent was removed by rotary evaporation to obtain a white solid. The crude product was dissolved in ethyl acetate, washed with deionized water, saturated sodium bicarbonate, and saturated brine, respectively, and dried over anhydrous magnesium sulfate. After removing the solvent, the target product, naphthyl propyl methyl acrylate monomer, was obtained.

[0067] (2) Preparation method of high viscosity fluoropolymer solution:

[0068] 30g of naphthalene methacrylate, 60g of octafluoroamyl methacrylate, and 20g of vinylcarbazole obtained above were dissolved in 90g of butyl acetate. The solution was stirred and dissolved to obtain a clear and transparent solution. Then, 2.2g of initiator TPPPI was added, and the mixture was heated to 65℃ and polymerized for 24h under magnetic stirring. After the reaction was completed, a transparent high-viscosity polymer solution with a viscosity of 6785 Pa·s was obtained.

[0069] Example 5

[0070] (1) Preparation method of methylnaphthol acrylate:

[0071] First, naphthol (0.2 mol), triethylamine (0.24 mol), and anhydrous tetrahydrofuran (90 mL) were added to a single-necked flask. Under ice-water bath conditions, methacryloyl chloride (0.25 mol) was added dropwise while stirring. After the addition was complete, the ice-water bath was removed, and the reaction was carried out at room temperature for 24 h. After the reaction was completed, a transparent liquid was obtained by filtration. The solvent was removed by rotary evaporation to obtain a white solid. The crude product was dissolved in ethyl acetate, washed with deionized water, saturated sodium bicarbonate, and saturated brine, respectively, and dried over anhydrous magnesium sulfate. After removing the solvent, the target product, methylnaphthol acrylate monomer, was obtained.

[0072] (2) Preparation method of high viscosity fluoropolymer solution:

[0073] 20g of naphthalene methacrylate, 30g of perfluorooctyl methacrylate, and 20g of vinylcarbazole obtained above were dissolved in 40g of DMF and stirred to obtain a clear and transparent solution. Then, 1.2g of initiator AIBN was added, and the mixture was heated to 70℃ and polymerized for 24h under magnetic stirring. After the reaction was completed, a transparent high-viscosity polymer solution with a viscosity of 7490 Pa·s was obtained.

[0074] Example 6

[0075] An anti-counterfeiting coating:

[0076] Substrate pretreatment: Immerse the glass slides in acetone, ethanol and water respectively and sonicate for 20 min. After removal, dry them in an oven at 65℃ for 30 min for later use.

[0077] Take 1 mL of the high-viscosity fluoropolymer solution prepared in Example 1, add butyl acetate to dilute to 7 mL, stir to obtain a homogeneous transparent solution, and at room temperature, use a pipette to transfer the transparent solution onto a glass slide. The spin coating speed is 1500 r / min and the spin coating time is 50 s. After drying in an oven at 70°C, an anti-counterfeiting coating is obtained after film formation.

[0078] After the membrane is irradiated with ultraviolet light through a mask, the naphthyl ester group rearranges to produce a hydroxy aromatic ketone structure, which exhibits fluorescence, revealing a clear "AB" pattern. This pattern has high resolution and clear content, as shown in the image. Figure 7 As shown.

[0079] Example 7

[0080] An anti-counterfeiting coating:

[0081] Take out 0.5 mL of the high-viscosity fluoropolymer solution prepared in Example 2, add butyl acetate to dilute to 10 mL, and obtain a white transparent liquid. Apply the liquid to a glass slide (the glass slide after substrate pretreatment in Example 6) by casting, and dry it in an oven at 50°C to form a film and obtain an anti-counterfeiting coating.

[0082] When the mask is exposed to TFA vapor stimulation, the originally white film displays clear blue numbers. After ammonia stimulation, it reverts to its original colorless state. Figure 8 As shown; repeating this cycle 10 times resulted in good stimulus response.

[0083] Example 9

[0084] An anti-counterfeiting coating:

[0085] Matrix pretreatment: Cut cotton fiber fabric (diameter of 10-20 micrometers) into regular shapes and immerse it in acetone, ethanol and water respectively for ultrasonic treatment for 30 minutes. After taking out the fabric, dry it in an 80℃ oven for 1 hour, and then dry it in a vacuum drying oven at 70℃ for 2 hours for later use.

[0086] The high-viscosity fluorine-containing solution prepared in Example 5 was dissolved in butyl acetate to prepare a polymer solution with a concentration of 3.0 wt%. The solution was stirred to form a uniform transparent solution. At room temperature, the pretreated fabric was immersed in the polymer solution and simultaneously ultrasonically treated for 15 min. After immersion, the fabric was dried in a vacuum oven at 70°C for 12 h to obtain the anti-counterfeiting coating.

[0087] The appearance of the fabric before and after dyeing is as follows: Figure 9 As shown in the figure, after one-step polymer impregnation, the fiber diameter of the fabric remains basically unchanged, maintaining a porous structure, but the fabric surface becomes smoother, indicating that the polymer adheres to the fabric surface.

[0088] Comparative Example 1

[0089] A high-viscosity polymer solution:

[0090] 30g of trifluoroethyl methacrylate and 8g of vinylcarbazole were dissolved in 40g of butyl acetate and stirred to obtain a clear and transparent solution. Then, 0.38g of initiator AIBN was added, and the mixture was heated to 70℃ and polymerized for 24h under magnetic stirring. After the reaction was completed, a transparent high-viscosity polymer solution with a viscosity of 5000 Pa·s was obtained.

[0091] After the reaction was completed, 1 mL of the high-viscosity polymer solution was taken out and diluted to 5 mL with butyl acetate, resulting in a white transparent liquid. After the solution was stimulated with ultraviolet light, the absorbance of the solution did not change, indicating that the photostimulation response part of the fluorinated copolymer is naphthalene methacrylate.

[0092] Comparative Example 2

[0093] A high-viscosity polymer solution:

[0094] 15g of naphthalene methacrylate and 30g of dodecafluoroheptyl methacrylate obtained in Example 2 were dissolved in 50g of butyl acetate. The solution was stirred and dissolved to obtain a clear and transparent solution. Then, 0.41g of initiator AIBN was added, and the mixture was heated to 70°C and polymerized for 24h under magnetic stirring. After the reaction was completed, a transparent high-viscosity polymer solution with a viscosity of 4800 Pa·s was obtained.

[0095] After the reaction was completed, 0.5 mL of the high-viscosity polymer solution was taken out and diluted to 5 mL with butyl acetate, resulting in a white transparent liquid. After adding 0.5 mL of LTFA to the solution, the solution color did not change, indicating that the acid-stimulated functional group of the fluorinated copolymer is a carbazole group.

[0096] Comparative Example 3

[0097] A high-viscosity polymer solution:

[0098] 20g of naphthalene acrylate, 40g of butyl methacrylate, and 15g of vinylcarbazole obtained in Example 3 were dissolved in 60g of DMF and stirred to obtain a clear and transparent solution. Then, 1.3g of initiator BPO was added, and the mixture was heated to 80°C and polymerized for 24h under magnetic stirring. After the reaction was completed, a transparent high-viscosity polymer solution with a viscosity of 5800 Pa·s was obtained.

[0099] Test case

[0100] A small amount of the high-viscosity polymer solution from Examples 1-5 was taken out, precipitated in anhydrous ethanol, filtered, and dried to obtain a white powder. The powder was then characterized by infrared spectroscopy. Figure 10 As shown in the figure, 2900-3000cm -1 These are the stretching vibration absorption peaks of the methyl and methylene groups in the copolymer structure, while the carbonyl absorption peak in the polymer structure mainly appears at 1741 cm⁻¹. -1 At this point, the absorption peak of the CF bond appears at 1109-1161 cm⁻¹. -1 .

[0101] Take 1 mL of each of the solutions from Example 3 and Comparative Example 3, add DMF to dilute to 7 mL, and obtain a white transparent liquid. Coat the solution onto a glass slide (the glass slide treated with the substrate of Example 6) by casting method, and dry it in an oven at 85°C for 10 h to obtain a film, i.e., an anti-counterfeiting coating.

[0102] Contact angle tests were performed on the thin film, such as... Figure 11 As shown, the contact angle of the film obtained in Example 3 was 120.5°, which was much higher than that in Comparative Example 3, indicating that the presence of fluorine elements gave the film surface better water resistance.

[0103] The film was placed in an aging chamber under light intensity of 60–180 W / m. 2Under irradiation conditions, the gloss of the film at 60° was measured at three locations at regular intervals according to GB / T 9754-2007. The curves showing the change in gloss of the films of Example 3 and Comparative Example 3 as a function of UV aging time are shown below. Figure 12 As shown.

[0104] The calculation method for the gloss loss rate of the adhesive film is shown in equation (1):

[0105] GL%=[(G0-G) / G0]*100%(1)

[0106] Where: GL is the gloss loss rate, %; G0 is the initial gloss of the film, %; G is the gloss of the film after the aging test, %.

[0107] like Figure 12 As shown, the gloss of the polymer films decreased over time under ultraviolet light irradiation. However, the gloss loss rate of the fluoropolymer film in Comparative Example 3 was much smaller than that of the non-fluoropolymer film in Comparative Example 2. After 500 hours of irradiation, the gloss loss rate was almost half that of Comparative Example 3. This indicates that the fluoropolymer film has good anti-aging properties, especially in anti-counterfeiting applications, where the presence of fluorinated groups effectively prevents damage from prolonged and frequent ultraviolet light stimulation.

[0108] Solutions from Examples 1-5 and Comparative Example 3 were added to butyl acetate to prepare a 3.0 wt% polymer solution. The mixture was stirred to obtain a homogeneous transparent solution. At room temperature, the transparent solution was transferred onto a glass slide using a pipette at a spin coating speed of 1500 r / min for 50 s. After drying in an oven at 70°C, an anti-counterfeiting coating was formed. The anti-counterfeiting coatings prepared from the solutions of Examples 1-5 and Comparative Example 3 were tested according to GB / T6739-2006, GB / T1771-2007, and GB / T 9286-1998 for hardness, alkali resistance, and adhesion. The results are shown in Table 1.

[0109] Table 1 Membrane performance data

[0110]

[0111] As shown in Table 1, the performance of the films in Examples 1-5 is better than that in Comparative Example 3, and the performance is even better with the increase of fluorine content. With the increase of fluorine content, the acid and alkali resistance increases, and the long fluorine chain increases the crystallization ability, thereby increasing the hardness and adhesion accordingly.

[0112] This invention provides a high-viscosity fluoropolymer solution and its application. Combining the advantages of resin polymers such as easy film formation, easy processing, and industrialization, a novel fluoropolymer based on naphthol, carbazole, and fluorine-containing functional groups is obtained. The polymer exhibits excellent light and acid stimuli responsiveness and UV resistance. The preparation method of this invention is simple, easy to operate, has good film-forming properties, long service life, and low cost. It can be industrialized and can provide dual anti-counterfeiting features, showing great application potential in anti-counterfeiting, information encryption, and other fields.

Claims

1. A high-viscosity fluoropolymer solution, characterized in that, The preparation method is as follows: Naphthalene methacrylate, fluorinated methacrylate, and vinylcarbazole are dissolved in solvent A and stirred to obtain a clear and transparent solution. Then, an initiator is added, and the mixture is heated to 60-90℃ under magnetic stirring for 16-24 hours to polymerize. After the reaction is completed, a transparent high-viscosity polymer solution with a viscosity range of 800-8000 Pa·s is obtained. The composition includes 2-20 wt% naphthyl methacrylate, 30-60 wt% fluorinated methacrylate, 2-30 wt% vinylcarbazole, and 10-50 wt% solvent A; the initiator accounts for 0.01-10% of the total monomer mass.

2. The high-viscosity fluoropolymer solution according to claim 1, characterized in that, The fluorinated methacrylate is one of trifluoroethyl methacrylate, tetrafluoropropyl methacrylate, hexafluorobutyl methacrylate, octafluoropentyl methacrylate, dodecafluoroheptyl methacrylate, and perfluorooctyl methacrylate.

3. The high-viscosity fluoropolymer solution according to claim 1, characterized in that, Preparation of the aforementioned naphthyl methacrylate: First, add naphthol, triethylamine and anhydrous tetrahydrofuran. Under ice-water bath conditions, add methacryloyl chloride dropwise while stirring. After the addition is complete, remove the ice-water bath and react at room temperature for 19-30 hours. After the reaction is complete, filter to obtain a transparent liquid. After rotary evaporation to remove the solvent, obtain a white solid. After post-treatment, obtain naphthyl methacrylate.

4. The high-viscosity fluoropolymer solution according to claim 3, characterized in that, The molar ratio of naphthol to triethylamine is 1:1 to 3, the molar ratio of naphthol to methacryloyl chloride is 1:1 to 1.5, and the amount of tetrahydrofuran added is 50-70 wt% of the system.

5. The high-viscosity fluoropolymer solution according to claim 3, characterized in that, The post-processing is as follows: the white solid is dissolved in solvent B, washed with deionized water, saturated sodium bicarbonate and saturated brine respectively, dried with anhydrous magnesium sulfate, and the target product naphthalene methacrylate is obtained after removing the solvent.

6. The high-viscosity fluoropolymer solution according to claim 1, characterized in that, The initiator is one of azobisisobutyronitrile, benzoyl peroxide, and tert-butyl peroxypentanoate; the solvent A is one of N,N-dimethylformamide, butyl acetate, ethyl acetate, and dimethyl sulfoxide.

7. The application of the high-viscosity fluoropolymer solution according to any one of claims 1-6 in the field of dual anti-counterfeiting.

8. The application of the high-viscosity fluoropolymer solution according to claim 7 in the field of dual anti-counterfeiting, characterized in that, A high-viscosity polymer solution is applied to a substrate to form a film, which is then used to obtain an anti-counterfeiting coating.

9. The application of the high-viscosity fluoropolymer solution according to claim 8 in the field of dual anti-counterfeiting, characterized in that, The specific preparation method of the anti-counterfeiting coating is as follows: a high-viscosity polymer solution is dissolved in solvent C to prepare a polymer solution with a concentration of 0.5-10wt%, and stirred to form a uniform transparent solution. At room temperature, the solution is applied to the substrate by spin coating, dip coating, or casting, and then vacuum dried to obtain the anti-counterfeiting coating.

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