Preparation method of rare earth polymer luminescent cluster anti-counterfeiting label

Abstract

The present invention relates to a method for preparing a rare earth polymer luminescent cluster anti-counterfeiting label, wherein acetoacetate glucan is prepared by transesterification reaction, and different Ln 3+ ions to produce rare earth polymer luminescent clusters Ln(GAA)3 with a variety of luminescent colors. Rare earth complexes composed of different molar ratios exhibit excitation-dependent properties, meaning that varying the excitation wavelength can produce various luminescent colors, including green, yellow, orange, red, and purple. Based on these luminescent properties, a solution of the non-excitation-dependent rare earth complex is used to treat paper, and an inkjet printer uses the excitation-dependent rare earth complex solution as ink to print anti-counterfeiting QR codes. Alternatively, the reverse process can be used to print anti-counterfeiting QR codes. The QR code is illuminated with UV light of specific excitation wavelengths, and only under these specific excitation wavelengths will the code emit a specific luminescent color, achieving multiple anti-counterfeiting measures. This method is simple and quick to produce and has broad application prospects in the anti-counterfeiting field.

Description

Technical Field

[0001] The invention belongs to the field of information security, and in particular relates to a method for preparing a rare earth polymer luminescent cluster anti-counterfeiting label. Background Art

[0002] Information security is related to human life safety, social stability and even national security. Fluorescent materials are widely used in encryption and anti-counterfeiting of important information due to their high concealment, low cost and excellent tunable optical properties. Trivalent lanthanide (LnIII) ​​ions have high application potential due to their structural diversity and unique luminescence properties. However, due to the forbidden symmetry of ff transitions and the shielding of 4f orbitals, the direct excitation of Ln(III) ions shows low luminescence efficiency. At present, the main method to overcome these problems is to find rare earth ions that can effectively sensitize Ln 3+ The key to modulating more efficient luminescence is to select ligands with desired functional groups. The design and development of luminescent materials is of great significance to both scientific research and industry. However, conventional organic luminescent materials containing multiple benzene rings or thick rings have significant disadvantages, such as poor biodegradability, high toxicity, ecological pollution, and complex and time-consuming synthesis steps, which severely limit their use. Complementing these traditional materials, unconventional luminophores (a class of luminophores with cluster luminescence properties) that do not contain traditional fluorescent chromophores have attracted considerable attention in the past few years. However, unconventional luminophores typically emit blue or green light with relatively high efficiency, while photoluminescence (PL) efficiency from yellow to red / near-infrared is quite low, limiting their widespread application. Numerous strategies, such as polymer structure modulation, solvation effects, hydrogen bonding interactions, thermal treatment, compression / decompression, base-mediated hydrolysis, and polymerization, have achieved some exciting progress in modulating the PL of unconventional luminophores. These strategies have demonstrated the feasibility and great potential of effectively modulating the emission of unconventional luminophores. According to current relevant literature reports, although some progress has been made in the fluorescence regulation of unconventional luminophores, such research is still in its infancy and there are still many challenges and research work. It is necessary to seek new strategies to meet the challenges. Summary of the Invention

[0003] The invention provides a method for preparing a rare earth polymer luminescent cluster anti-counterfeiting label, thereby improving the security level.

[0004] The technical solution of the present invention:

[0005] A method for preparing a rare earth polymer luminescent cluster anti-counterfeiting label comprises the following steps:

[0006] S1, dissolving dextran in a mixture of DMF and ionic liquid to obtain a clear solution;

[0007] S2, mixing the clear solution obtained in S1 with acetoacetate to react and obtain an acetoacetate glucan mixture;

[0008] S3, placing the acetoacetate dextran mixture in S2 into a dialysis bag with a certain molecular weight cut-off, soaking the dialysis bag in water for 2-3 days, and detecting that there is no ester residue in the dialysate, that is, the dialysis is completed, and then freeze-drying is performed to obtain pure acetoacetate dextran;

[0009] S4, dissolving pure acetoacetate dextran in water to obtain an acetoacetate dextran aqueous solution, adding one of the rare earth ions to the acetoacetate dextran aqueous solution, and stirring at room temperature to obtain a mixed solution of acetoacetate dextran and rare earth ions; the rare earth ions include Eu, Tb and Dy;

[0010] S5, adding a poor solvent to the mixed solution of acetoacetic dextran and rare earth ions obtained in S4, centrifuging, washing, and freeze-drying to obtain a rare earth polymer luminescent cluster;

[0011] S6, dissolving the rare earth polymer luminescent cluster in DMF to form Eu(acetoacetate dextran)3 DMF solution, Tb(acetoacetate dextran)3 DMF solution and Dy(acetoacetate dextran)3 DMF solution respectively;

[0012] The DMF solution of Eu (acetoacetate glucan) 3 and the DMF solution of Tb (acetoacetate glucan) 3 are mixed to form a DMF solution mixture of Eu (acetoacetate glucan) 3 / Tb (acetoacetate glucan) 3;

[0013] Use one of the Dy(acetoacetyl glucan)3 in DMF solution and the Eu(acetoacetyl glucan)3 / Tb(acetoacetyl glucan)3 in DMF solution mixture to completely smear the paper three times, and spread it after drying; use the other as ink to print the QR code using an inkjet printer;

[0014] S7. Use two UV lamps with two excitation wavelengths to irradiate the printed paper respectively. The two excitation light irradiation patterns can be combined to produce an anti-counterfeiting label.

[0015] Preferably, the ionic liquid in S1 is one of 1-methylimidazolium chloride, 1-methylimidazolium tetrafluoroborate, 1-methylimidazolium hexafluorophosphate, 1-allyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium bromide, 1-allyl-3-methylimidazolium tetrafluoroborate, 1-allyl-3-methylimidazolium hexafluorophosphate, 1-allylimidazole chloride, 1-allylimidazole bromide, 1-allylimidazole tetrafluoroborate, 1-allylimidazole hexafluorophosphate and 1-allyl-3-vinylimidazole chloride;

[0016] The molar ratio of dextran, DMF, and ionic liquid is 1:10-40:8-50;

[0017] Preferably, the mass ratio of the clear solution in S2 to the acetoacetate is 1:4-15.

[0018] The reaction temperature in S2 is 80-150° C., the reaction time is 4-6 h, and S2 is reacted under nitrogen or argon protection.

[0019] Preferably, the molecular weight cut-off in S3 is one of 500, 1000, 2000, 3500, 8000, 10000 and 15000; the freeze-drying temperature of S3 is -80°C to -50°C, and the freeze-drying time is 20-30 hours.

[0020] Preferably, the molar ratio of acetoacetated dextran: water: rare earth ions in S4 is 1-10:150-500:1.

[0021] Preferably, the poor solvent in S5 is one of anhydrous methanol, anhydrous ethanol, ethylene glycol, tetrahydrofuran and acetonitrile; the molar ratio of the poor solvent: acetoacetic dextran: rare earth ion is 100-850:1-10:1;

[0022] The centrifugal speed in S5 is 5000-10000 r / min, washed with the above-mentioned poor solvent, the temperature is minus 80° C. to minus 50° C., and freeze-dried for 10-20 hours.

[0023] Preferably, the mass ratio of the rare earth polymer luminescent cluster in S6 to DMF applied to paper is 1:4-80; the mass ratio as ink is 1:1-10;

[0024] The molar ratio of Eu(acetoacetate dextran)3 to Tb(acetoacetate dextran)3 in the DMF solution of Eu(acetoacetate dextran)3 and the DMF solution of Tb(acetoacetate dextran)3 is one of 3:2, 2:1, 1:1, 1:2 and 2:3.

[0025] Preferably, the excitation wavelengths of the two ultraviolet lamps in S7 are any two of 320 nm, 340 nm, 365 nm, 380 nm and 390 nm.

[0026] Beneficial effects of the present invention:

[0027] The present invention designs rare earth-β-diketone polymer cluster luminescent materials, by chelating different Ln 3+(Eu, Tb, Dy) can produce multi-color tunable fluorescence colors. In particular, when the molar ratio of Eu(GAA)3 / Tb(GAA)3 is 1:1, a variety of luminescent colors, including green, yellow, orange, red, and purple, can be obtained by changing the excitation wavelength. Combining this characteristic of varying the excitation wavelength to achieve different emission colors, the application of inkjet-printed QR code anti-counterfeiting further enhances security, providing new ideas for advanced anti-counterfeiting and broadening new paths in the field of advanced information security.

[0028] The polymer luminescent cluster prepared by the method of the present invention has excellent luminescent performance and has great application in information security.

[0029] The method of the present invention requires moderate conditions, has strong operability, good reproducibility, and the obtained product quantity is stable, economical and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a synthetic route for acetoacetate glucan in Example 1 of the present invention.

[0031] Figure 2 These are photographs of different rare earth polymer luminescent clusters obtained in Example 2 of the present invention.

[0032] Figure 3 This is a two-dimensional code advanced anti-counterfeiting label image printed by inkjet according to embodiment 3 of the present invention.

[0033] Figure 4 This is another advanced anti-counterfeiting label image of a two-dimensional code printed by inkjet printing according to Example 4 of the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to examples and drawings, but the protection scope of the present invention is not limited to these examples.

[0035] The room temperature of the present invention is 4-38° C.; the abbreviation of acetoacetate glucan is GAA; the Chinese name of DMF is N,N-dimethylformamide.

[0036] Example 1

[0037] Dissolve 1g of glucan in a mixture of 20mL of DMF and 13g of 1-allyl-3-methylimidazolium chloride ionic liquid to obtain a clear solution; raise the solution temperature to 110°C, then slowly add 4.5g of tert-butyl acetoacetate to obtain a mixture of glucan acetoacetate; connect an argon device for argon protection and react for 4h; after cooling to room temperature, place the mixture in a dialysis bag with a molecular weight cutoff of 1000, soak the dialysis bag in water for 2-3 days, and detect that there is no ester residue in the dialysate, indicating that the dialysis is complete. Then freeze-dry at -50°C for 22 hours to obtain pure glucan acetoacetate (abbreviated as GAA). The synthesis route is shown in Figure 1 ;

[0038] 0.4 g of GAA was dissolved in 10 mL of water to obtain a GAA aqueous solution, 1.5 mmol of a rare earth ion was added, and the mixture was stirred at room temperature for one day to obtain a mixed solution of GAA and rare earth ions; the rare earth ions included Eu, Tb, and Dy; 55 mL of acetonitrile was added to the mixture, and the mixture was centrifuged at 9000 rpm, washed three times with acetonitrile, and freeze-dried at -50°C for 15 hours to obtain a rare earth polymer luminescent cluster;

[0039] Different masses of rare earth polymer luminescent clusters were dissolved in 1 mL of DMF to prepare 140 mg / mL Dy(GAA)3 DMF solution, 25 mg / mL Eu(GAA)3 DMF solution, 25 mg / mL Eu(GAA)3 and 25 mg / mL Tb(GAA)3 DMF solution, and 14 mg / mL Eu(GAA)3 and 14 mg / mL Tb(GAA)3 DMF solution respectively.

[0040] Coat the paper three times with a DMF solution of 140 mg / mL Dy(GAA)3, and spread it after drying; use a DMF solution containing 25 mg / mL Leu(GAA)3 and 25 mg / mL Tb(GAA)3 as ink and print a QR code using an inkjet printer; alternatively, coat the paper three times with a DMF solution containing 14 mg / mL Eu(GAA)3 and 14 mg / mL Tb(GAA)3, and use a DMF solution of 25 mg / mL Eu(GAA)3 as ink to print a QR code; irradiate the printed paper with 365 nm and 390 nm ultraviolet lamps respectively, and combine the two excitation light irradiation patterns to make an anti-counterfeiting label.

[0041] Example 2

[0042] 1 g of dextran was dissolved in a mixture of 20 mL of DMF and 15 g of 1-allyl-3-methylimidazolium bromide ionic liquid to obtain a clear solution; the solution temperature was raised to 100°C, and then 5.5 g of tert-butyl acetoacetate was slowly added to obtain a mixture of acetoacetated dextran; a nitrogen gas system was connected for nitrogen protection, and the reaction was carried out for 4.5 hours; after cooling to room temperature, the mixture was placed in a 2000 molecular weight cutoff dialysis bag, which was soaked in water for 2-3 days. The dialysis was completed when no ester residue was found in the dialysate, and then freeze-dried at -70°C for 25 hours to obtain pure GAA;

[0043] 0.5g of pure GAA was dissolved in 10mL of water to obtain a GAA aqueous solution. 1mmol of a rare earth ion was added and stirred at room temperature for one day to obtain a mixture of GAA and rare earth ions; the rare earth ions included Eu, Tb, and Dy. 48mL of ethylene glycol was added to the mixture, centrifuged at 7000r / min, washed three times with ethylene glycol, and freeze-dried at -70°C for 18 hours to obtain a rare earth polymer luminescent cluster. Figure 2 ;

[0044] Different masses of rare earth polymer luminescent clusters were dissolved in 1 mL DMF to form 160 mg / mL Dy(GAA)3 DMF solution, 30 mg / mL Eu(GAA)3 DMF solution, 31 mg / mL Eu(GAA)3 and 31 mg / mL Tb(GAA)3 DMF solution, and 16 mg / mL Eu(GAA)3 and 16 mg / mL Tb(GAA)3 DMF solution, respectively.

[0045] Coat the paper three times with a 160mg / mL Dy(GAA)3 DMF solution, and spread it after drying; use a DMF solution containing 31mg / mL Leu(GAA)3 and 31mg / mL Tb(GAA)3 as ink and use an inkjet printer to print a QR code; alternatively, coat the paper three times with a DMF solution containing 16mg / mL Eu(GAA)3 and 16mg / mL Tb(GAA)3, and use a DMF solution of 30mg / mL Eu(GAA)3 as ink to print a QR code; irradiate the printed paper with 365nm and 390nm ultraviolet lamps respectively, and combine the two excitation light irradiation patterns to make an anti-counterfeiting label.

[0046] Example 3

[0047] 1 g of dextran was dissolved in a mixture of 20 mL of DMF and 19 g of 1-allyl-3-methylimidazolium chloride ionic liquid to obtain a clear solution; the solution temperature was raised to 120°C, and then 5 g of tert-butyl acetoacetate was slowly added to obtain a mixture of acetoacetated dextran; a nitrogen gas device was connected for nitrogen protection, and the reaction was carried out for 5 hours; after cooling to room temperature, the mixture was placed in a dialysis bag with a molecular weight cutoff of 3500, and the dialysis bag was soaked in water for 2-3 days. The dialysis was completed when no ester residue was found in the dialysate, and then freeze-dried at -60°C for 24 hours to obtain pure GAA;

[0048] 0.4 g of GAA was dissolved in 10 mL of water to obtain a GAA aqueous solution, 2 mmol of a rare earth ion was added, and the mixture was stirred at room temperature for one day to obtain a mixed solution of GAA and rare earth ions; the rare earth ions included Eu, Tb, and Dy; 50 mL of anhydrous ethanol was added to the mixture, and the mixture was centrifuged at 8000 rpm, washed three times with anhydrous ethanol, and freeze-dried at -60°C for 12 hours to obtain a rare earth polymer luminescent cluster;

[0049] Different masses of rare earth polymer luminescent clusters were dissolved in 1 mL DMF to form 150 mg / mL Dy(GAA)3 DMF solution, 35 mg / mL Eu(GAA)3 DMF solution; 35 mg / mL Eu(GAA)3 and 35 mg / mL Tb(GAA)3 DMF solution; 15 mg / mL Eu(GAA)3 and 15 mg / mL Tb(GAA)3 DMF solution;

[0050] Use 150mg / mL Dy(GAA)3 in DMF solution to completely coat the paper three times and spread it after drying; use DMF solution containing 35mg / mL Eu(GAA)3 and 35mg / mL Tb(GAA)3 as ink and use an inkjet printer to print the QR code. Figure 3 Alternatively, smear the paper three times with 15 mg / mL Eu(GAA)3 and 15 mg / mL Tb(GAA)3 in DMF solution, and use 35 mg / mL Eu(GAA)3 in DMF solution as ink to print the QR code; irradiate the printed paper with 365 nm and 390 nm ultraviolet lamps respectively, and combine the two excitation light irradiation patterns to make an anti-counterfeiting label.

[0051] Example 4

[0052] 1 g of dextran was dissolved in a mixture of 20 mL of DMF and 10 g of 1-allylimidazolium chloride ionic liquid to obtain a clear solution; the solution temperature was raised to 140°C, and then 6 g of tert-butyl acetoacetate was slowly added to obtain an acetoacetate dextran mixture; an argon gas device was connected for argon protection, and the reaction was carried out for 5.5 hours; after cooling to room temperature, the mixture was placed in a dialysis bag with a molecular weight cutoff of 8000, and the dialysis bag was soaked in water for 2-3 days. The dialysis was completed when no ester residue was found in the dialysate, and then freeze-dried at -80°C for 28 hours to obtain pure GAA;

[0053] 0.4 g of GAA was dissolved in 10 mL of water to obtain a GAA aqueous solution. 1.2 mmol of a rare earth ion was added to the aqueous solution and stirred at room temperature for one day to obtain a mixed solution of GAA and rare earth ions; the rare earth ions included Eu, Tb, and Dy. 46 mL of anhydrous methanol was added to the mixed solution, and the mixture was centrifuged at 6000 rpm, washed three times with anhydrous methanol, and freeze-dried at -80°C for 16 hours to obtain a rare earth polymer luminescent cluster.

[0054] Different masses of rare earth polymer luminescent clusters were dissolved in 1 mL DMF to form 165 mg / mL Dy(GAA)3 DMF solution, 40 mg / mL Eu(GAA)3 DMF solution; 40 mg / mL Eu(GAA)3 and 40 mg / mL Tb(GAA)3 DMF solution; and 16 mg / mL Eu(GAA)3 and 16 mg / mL Tb(GAA)3 DMF solution.

[0055] Coat the paper three times with a 165mg / mL Dy(GAA)3 solution in DMF and spread it after drying; use a DMF solution containing 40mg / mL Eu(GAA)3 and 40mg / mL Tb(GAA)3 as ink and print a QR code using an inkjet printer; alternatively, coat the paper three times with a 16mg / mL Eu(GAA)3 and 16mg / mL Tb(GAA)3 solution in DMF and use a 40mg / mL Eu(GAA)3 solution in DMF as ink to print a QR code; irradiate the printed paper with 365nm and 390nm UV lamps respectively. Combining the two excitation light irradiation patterns can produce an anti-counterfeiting label, see Figure 4 .

[0056] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a rare earth polymer luminescent cluster anti-counterfeiting label, characterized in that: The following steps are involved: S1, dissolving dextran in a mixture of DMF and ionic liquid to obtain a clear solution; S2, mixing the clear solution obtained in S1 with acetoacetate to react and obtain an acetoacetate glucan mixture; S3, placing the acetoacetate dextran mixture in S2 into a dialysis bag with a certain molecular weight cut-off, soaking the dialysis bag in water for 2-3 days, and detecting that there is no ester residue in the dialysate, that is, the dialysis is completed, and then freeze-drying is performed to obtain pure acetoacetate dextran; S4, dissolving pure acetoacetate dextran in water to obtain an acetoacetate dextran aqueous solution, adding one of the rare earth ions to the acetoacetate dextran aqueous solution, and stirring at room temperature to obtain a mixed solution of acetoacetate dextran and rare earth ions; the rare earth ions include Eu, Tb and Dy; S5. Adding a poor solvent to the mixture of acetoacetic dextran and rare earth ions obtained in S4, centrifuging, washing, and freeze-drying to obtain a rare earth polymer luminescent cluster; the poor solvent in S5 is one of anhydrous methanol, anhydrous ethanol, ethylene glycol, tetrahydrofuran, and acetonitrile; the molar ratio of the poor solvent: acetoacetic dextran: rare earth ion is 100-850:1-10:1; S6, dissolving the rare earth polymer luminescent cluster in DMF to form Eu(acetoacetate dextran)3 DMF solution, Tb(acetoacetate dextran)3 DMF solution and Dy(acetoacetate dextran)3 DMF solution respectively; The Eu(acetoacetate glucan)3 DMF solution and the Tb(acetoacetate glucan)3 DMF solution are mixed to form a Eu(acetoacetate glucan)3 / Tb(acetoacetate glucan)3 DMF solution mixture; Use one of the Dy (acetoacetyl glucan) 3 in DMF solution and the Eu (acetoacetyl glucan) 3 / Tb (acetoacetyl glucan) 3 in DMF solution mixture to completely coat the paper three times, and spread it after drying; use the other as ink to print the QR code using an inkjet printer; S7. Use two UV lamps with two excitation wavelengths to irradiate the printed paper respectively. The two excitation light irradiation patterns can be combined to produce an anti-counterfeiting label.

2. The method for preparing a rare earth polymer luminescent cluster anti-counterfeiting label according to claim 1, characterized in that: The ionic liquid in S1 is one of 1-methylimidazolium chloride, 1-methylimidazolium tetrafluoroborate, 1-methylimidazolium hexafluorophosphate, 1-allyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium bromide, 1-allyl-3-methylimidazolium tetrafluoroborate, 1-allyl-3-methylimidazolium hexafluorophosphate, 1-allylimidazole chloride, 1-allylimidazole bromide, 1-allylimidazole tetrafluoroborate, 1-allylimidazole hexafluorophosphate and 1-allyl-3-vinylimidazole chloride; The molar ratio of dextran, DMF and ionic liquid is 1:10-40:8-50.

3. The method for preparing a rare earth polymer luminescent cluster anti-counterfeiting label according to claim 1, characterized in that: The mass ratio of the clear solution in S2 to acetoacetate is 1:4-15; The reaction temperature in S2 is 80-150° C., the reaction time is 4-6 h, and S2 is reacted under nitrogen or argon protection.

4. The method for preparing a rare earth polymer luminescent cluster anti-counterfeiting label according to claim 1, characterized in that: The molecular weight cut-off of S3 is one of 500, 1000, 2000, 3500, 8000, 10000 and 15000; the freeze-drying temperature of S3 is minus 80° C. to minus 50° C., and the freeze-drying time is 20-30 hours.

5. The method for preparing a rare earth polymer luminescent cluster anti-counterfeiting label according to claim 1, characterized in that: The molar ratio of acetoacetated dextran: water: rare earth ions in S4 is 1-10:150-500:

1.

6. The method for preparing a rare earth polymer luminescent cluster anti-counterfeiting label according to claim 1, characterized in that: The centrifugal speed in S5 is 5000-10000 r / min, washed with the above-mentioned poor solvent, the temperature is minus 80° C. to minus 50° C., and freeze-dried for 10-20 hours.

7. The method for preparing a rare earth polymer luminescent cluster anti-counterfeiting label according to claim 1, characterized in that: The mass ratio of rare earth polymer luminescent clusters and DMF in S6 applied to paper is 1:4-80; the mass ratio as ink is 1:1-10; The molar ratio of Eu(acetoacetate dextran)3 to Tb(acetoacetate dextran)3 in the DMF solution of Eu(acetoacetate dextran)3 and the DMF solution of Tb(acetoacetate dextran)3 is one of 3:2, 2:1, 1:1, 1:2 and 2:

3.

8. The method for preparing a rare earth polymer luminescent cluster anti-counterfeiting label according to claim 1, characterized in that: The excitation wavelengths of the two UV lamps in S7 are any two of 320 nm, 340 nm, 365 nm, 380 nm and 390 nm.

Images