A dual-fluorescence anti-counterfeiting fiber made of a plant-based upconversion and downconversion material, its preparation method and application

Abstract

The present invention discloses a dual-fluorescence anti-counterfeiting fiber of plant-based upconversion and downconversion materials, its preparation method and application. EuCl<subgt;3< / subgt; solution and TTA solution are successively added to the plant fiber solution, and then the pH is adjusted to 7 and stirred for 60 min. Then, NaYF<subgt;4< / subgt;:Yb,Er solution is added. Finally, it is washed three times with deionized water, filtered by suction, and dried to obtain the dual-fluorescence anti-counterfeiting fiber of plant-based upconversion and downconversion materials. The obtained dual-fluorescence fiber of upconversion and downconversion materials can achieve green fluorescence emission under 980 nm excitation and red fluorescence emission under 365 nm excitation. The present invention not only endows the fiber with important application value of dual-fluorescence performance in the field of anti-counterfeiting, but also has a simple preparation process, easy-to-control conditions and no pollution to the environment.

Description

Technical Field

[0001] The present invention relates to the technical field of functional fibers, and in particular to a dual-fluorescence anti-counterfeiting fiber doped with plant-based upconversion and downconversion materials, and a preparation method and application thereof. Background Art

[0002] Fluorescent anti-counterfeiting fibers have been widely used in various certificates, bills, banknotes, stamps and packaging. The research on traditional fluorescent anti-counterfeiting fibers mainly focuses on synthetic fibers excited by a single wavelength, and the fluorescent substances are added during the chemical fiber manufacturing process. Due to the property differences between synthetic fibers and plant fibers, the papermaking performance of anti-counterfeiting paper is also poor; at the same time, the biggest problem of chemical fibers is environmental incompatibility, and the waste of chemical fibers is difficult to degrade and has become a new pollution source; in addition, the luminescent fibers excited by a single wavelength are relatively easy to be imitated by counterfeiters technically.

[0003] Since plant fibers are hydrophilic materials and upconversion materials are lipophilic materials, currently, after modifying the upconversion materials, the upconversion materials are loaded on plant fibers, which not only greatly increases the cost but also has complex operations. Downconversion materials are often loaded on fibers by modifying the fibers or depositing them. These two methods are either complex in operation or the downconversion materials are not firmly loaded on the fibers. At present, it has not been possible to load both upconversion and downconversion materials on plant fibers at the same time, so the existing fluorescent plant fibers are often single fluorescent fibers.

[0004] Therefore, in order to solve a series of problems such as the easy counterfeiting and non-degradability of single-fluorescent anti-counterfeiting fibers in the current anti-counterfeiting fiber materials, the present invention discloses a dual-fluorescent anti-counterfeiting fiber based on plant-based upconversion and downconversion materials and a preparation method thereof. Summary of the Invention

[0005] The purpose of the present invention is to provide a dual-fluorescent anti-counterfeiting fiber based on plant-based upconversion and downconversion materials and a preparation method thereof. In order to achieve the above purpose, the present invention provides the following technical solutions:

[0006] A preparation method of a dual-fluorescent anti-counterfeiting fiber based on plant-based upconversion and downconversion materials, characterized by comprising the following steps:

[0007] S1, uniformly dispersing the NaYF4:Yb,Er upconversion material in a PEI solution; the molecular weight of the PEI is 1800-100000; the PEI is polyethyleneimine;

[0008] S2, preparing a water suspension of plant fibers, adding an europium chloride solution and TTA to the suspension, and then adjusting the pH to 6-8, and reacting for 30-90 min; the TTA is a 2-thiophenecarbonyltrifluoroacetone solution;

[0009] S3. Add the NaYF4:Yb,Er solution obtained in S1 to the solution obtained in S2 and react for 10 - 60 min;

[0010] S4. After washing, suction filtration, and vacuum drying, a dual - fluorescence anti - counterfeiting fiber of plant - based up - conversion and down - conversion materials is obtained.

[0011] Preferably, the weight ratio of each raw material is: plant fiber 30 - 95%, NaYF4:Yb,Er up - conversion material 1 - 15%, europium chloride 1% - 15%, and TTA 1 - 45%.

[0012] Preferably, the NaYF4:Yb,Er up - conversion material in S1 is prepared in one step by a hydrothermal method, which includes the following steps: Mix the inorganic salt solutions containing Y, Yb, and Er, NaOH solution, oleic acid, ethanol solution, and NaF solution evenly, keep them at 160 °C - 200 °C for 8 h - 12 h, and after cooling, wash, dry, and grind to obtain the NaYF4:Yb,Er up - conversion material; the molar ratio of Y, Yb, and Er metal ions in the inorganic salt solutions of Y, Yb, and Er is 75% - 80%:18% - 24%:1% - 2%.

[0013] Preferably, the inorganic salt solutions of Y, Yb, and Er are chloride salt solutions; the molar ratio of Y, Yb, and Er metal ions is 78%:20%:2%.

[0014] Preferably, the concentration of the europium chloride solution in S2 is 1 mmol / L - 15 mmol / L, the TTA solution is 3 mmol / L - 45 mmol / L, and the molar amount ratio of the two is 1:3.

[0015] Preferably, ammonia water or sodium hydroxide is used in S2 to adjust the pH, the pH value is 6 - 7, the reaction time is 60 min; the reaction time in S3 is 30 min.

[0016] Preferably, in S4, it is washed 3 times with deionized water, the vacuum drying temperature is 40 - 80 °C, and the vacuum drying time is 12 h.

[0017] Preferably, the molecular weight of the PEI is 60000.

[0018] Preferably, the plant fiber is one or more of wood fiber, bamboo fiber, cotton fiber, hemp fiber, palm fiber, grass fiber, and bast fiber.

[0019] Preferably, the beating degree of the plant fiber is 13 - 75 °SR.

[0020] The dual - fluorescence anti - counterfeiting fiber of plant - based up - conversion and down - conversion materials prepared by the above method.

[0021] Application of the dual-fluorescence anti-counterfeiting fiber made of plant-based upconversion and downconversion materials, characterized in that it is applied to the field of anti-counterfeiting fibers.

[0022] In the present invention, an aqueous substance PEI is used to wrap the upconversion material, and the upconversion material is loaded on the plant fiber by the electrostatic interaction between PEI and the plant fiber. At the same time, by using the coordination effect between the downconversion material and the amino group on PEI, the downconversion material is also loaded on the plant fiber, obtaining a dual-fluorescence anti-counterfeiting fiber made of plant-based up- and down-conversion materials. Compared with the prior art, the advantages of the present invention are as follows:

[0023] (1) The fluorescent anti-counterfeiting fiber uses degradable plant fiber as the raw material and is environmentally friendly without pollution.

[0024] (2) Compared with the preparation method of traditional fluorescent anti-counterfeiting fibers, this fiber has the advantages of simple preparation process and easy control of conditions.

[0025] (3) Compared with traditional single-fluorescence anti-counterfeiting fibers, this preparation method combines plant fibers with rare earth europium chloride and its complexes, and NaYF4:Yb,Er upconversion materials to obtain a dual-fluorescence anti-counterfeiting fiber, further improving the technical problem that traditional fluorescent anti-counterfeiting fibers are relatively easy to be imitated by counterfeiters. Description of the Drawings

[0026] Figure 1 Scanning electron micrograph of the dual-fluorescence anti-counterfeiting fiber made of plant-based upconversion and downconversion materials prepared in Example 1.

[0027] Figure 2 Fluorescence effect diagram of the dual-fluorescence anti-counterfeiting fiber made of plant-based upconversion and downconversion materials prepared in Example 1.

[0028] Figure 3 Scanning electron micrograph of the dual-fluorescence anti-counterfeiting fiber made of plant-based upconversion and downconversion materials prepared in Example 2.

[0029] Figure 4 Scanning electron micrograph of the dual-fluorescence anti-counterfeiting fiber made of plant-based upconversion and downconversion materials prepared in Example 3.

[0030] Figure 5 Scanning electron micrograph of the dual-fluorescence anti-counterfeiting fiber made of plant-based upconversion and downconversion materials prepared in Example 4.

[0031] Figure 6 Scanning electron micrograph of the dual-fluorescence anti-counterfeiting fiber made of plant-based upconversion and downconversion materials prepared in Example 5. Detailed Embodiments

[0032] The present invention will be further described below in conjunction with the specific embodiments.

[0033] The plant fibers used in the following examples were all provided by Guangxi Huaxian New Materials Co., Ltd.

[0034] Example 1

[0035] In this example, the raw materials and reagents for preparing the dual-fluorescence anti-counterfeiting fibers of plant-based upconversion and downconversion materials include: natural-color Chinese fir fiber pulp with a beating degree of 13°SR, YCl3·6H2O, YbCl3·6H2O, ErCl3·6H2O, oleic acid, NaF, PEI, europium chloride, TTA, sodium hydroxide, and deionized water and ethanol are also required during the preparation process. The molecular weight of PEI is 60,000.

[0036] In this example, the preparation method of the dual-fluorescence anti-counterfeiting fibers of plant-based upconversion and downconversion materials is as follows:

[0037] (1) Prepare the NaYF4:Yb,Er upconversion material by a one-step hydrothermal method: After mixing 0.936 mL of 0.2 mol / L YCl3 solution, 0.24 mL of 0.2 mol / L YbCl3 solution, and 0.24 mL of 0.02 mol / L ErCl3 solution, add them to the mixed solution of NaF solution, NaOH solution, oleic acid, and ethanol solution, mix evenly, keep warm at 160 °C to 200 °C for 8 h to 12 h, wash with ethanol and centrifuge after cooling, vacuum dry the precipitate at 60 °C for 12 h, and obtain the NaYF4:Yb,Er upconversion material after grinding;

[0038] (2) Weigh 0.1 g of PEI and dissolve it in 10 mL of water, and evenly disperse 0.02 g of the NaYF4:Yb,Er upconversion material obtained in step (1) in the PEI aqueous solution;

[0039] (3) Disperse the plant fiber pulp containing 1 g of absolute dry Chinese fir fiber in 1000 ml of water to form an aqueous suspension, and dropwise add 5 mL of 6 mmol / L EuCl3 solution and 15 mL of 6 mmol / L TTA to the suspension, adjust the pH to 6 with NaOH solution, and react for 60 min;

[0040] (4) Add the NaYF_{4}:Yb,Er solution obtained in step (2) to the fiber suspension obtained in step (3), stir for 30 min, and stop the reaction;

[0041] (5) Finally, after repeatedly washing three times with deionized water, filtering by suction, and drying at 60 °C for 12 h, the dual-fluorescence anti-counterfeiting fibers of plant-based upconversion and downconversion materials are obtained.

[0042] Example 2

[0043] In this example, the raw materials and reagents for preparing the dual-fluorescent anti-counterfeiting fiber of plant-based upconversion and downconversion materials include: natural sisal fiber pulp with a beating degree of 50°SR, YCl3·6H2O, YbCl3·6H2O, ErCl3·6H2O, oleic acid, NaF, PEI, europium chloride, TTA, sodium hydroxide. Deionized water and ethanol are also required during the preparation process. The molecular weight of PEI is 60,000.

[0044] In this example, the preparation method of the dual-fluorescent anti-counterfeiting fiber of plant-based upconversion and downconversion materials is as follows:

[0045] (1) One-step preparation of NaYF4:Yb,Er upconversion material by hydrothermal method: After mixing 0.936 mL of 0.2 mol / L YCl3 solution, 0.24 mL of 0.2 mol / L YbCl3 solution, and 0.24 mL of 0.02 mol / L ErCl3 solution, add them to the mixed solution of NaF solution, NaOH solution, oleic acid, and ethanol solution. Mix well, keep warm at 160 °C - 200 °C for 8 h - 12 h, wash with ethanol and centrifuge after cooling, vacuum dry the precipitate at 60 °C for 12 h, and obtain the NaYF4:Yb,Er upconversion material after grinding;

[0046] (2) Weigh 0.1 g of PEI and dissolve it in 10 mL, and disperse 0.02 g of the NaYF4:Yb,Er upconversion material obtained in step (1) evenly in the PEI aqueous solution;

[0047] (3) Disperse the plant fiber pulp containing 2 g of absolute dry sisal fiber in 1500 ml of water to form an aqueous suspension, and add 8 mL of 6 mmol / L EuCl3 solution and 24 mL of 6 mmol / L TTA dropwise to the suspension. Adjust the pH to 6.5 with NaOH solution and react for 60 min;

[0048] (4) Dropwise add the NaYF4:Yb,Er solution obtained in step (2) to the fiber suspension obtained in step (3), stir for 10 min, and stop the reaction;

[0049] (5) Finally, obtain the dual-fluorescent anti-counterfeiting fiber of plant-based upconversion and downconversion materials after washing three times repeatedly with deionized water, suction filtration, and drying at 60 °C for 12 h.

[0050] Example 3

[0051] In this example, the raw materials and reagents for preparing the dual-fluorescence anti-counterfeiting fibers of plant-based up-conversion and down-conversion materials include: natural bamboo fiber pulp with a beating degree of 30°SR, YCl3·6H2O, YbCl3·6H2O, ErCl3·6H2O, oleic acid, NaF, PEI, europium chloride, TTA, sodium hydroxide. Deionized water and ethanol are also required during the preparation process. The molecular weight of PEI is 60,000.

[0052] In this example, the preparation method of the dual-fluorescence anti-counterfeiting fibers of plant-based up-conversion and down-conversion materials is as follows:

[0053] (1) Prepare the NaYF4:Yb,Er up-conversion material by a one-step hydrothermal method: After mixing 0.936 mL of 0.2 mol / L YCl3 solution, 0.24 mL of 0.2 mol / L YbCl3 solution, and 0.24 mL of 0.02 mol / L ErCl3 solution, add them to the mixed solution of NaF solution, NaOH solution, oleic acid, and ethanol solution, mix evenly, keep warm at 160°C - 200°C for 8 h - 12 h, wash with ethanol and centrifuge after cooling, vacuum dry the precipitate at 60°C for 12 h, and obtain the NaYF4:Yb,Er up-conversion material after grinding;

[0054] (2) Weigh 0.1 g of PEI and dissolve it in 10 mL, and disperse 0.02 g of the NaYF4:Yb,Er up-conversion material obtained in step (1) evenly in the PEI aqueous solution;

[0055] (3) Disperse the plant fiber pulp containing 1 g of absolute dry bamboo fiber in 2000 ml of water to form an aqueous suspension, and add 5 mL of 6 mmol / L EuCl3 solution and 15 mL of 6 mmol / L TTA dropwise to the suspension, adjust the pH to 6 with NaOH solution, and react for 90 min;

[0056] (4) Dropwise add the NaYF4:Yb,Er solution obtained in step (2) to the fiber suspension obtained in step (3), stir for 60 min, and stop the reaction;

[0057] (5) Finally, obtain the dual-fluorescence anti-counterfeiting fibers of plant-based up-conversion and down-conversion materials after washing three times repeatedly with deionized water, suction filtration, and drying at 60°C for 12 h.

[0058] Example 4

[0059] In this example, the raw materials and reagents for preparing the dual-fluorescent anti-counterfeiting fiber of plant-based upconversion and downconversion materials include: natural color Chinese alpine rush fiber pulp with a beating degree of 17°SR, YCl3·6H2O, YbCl3·6H2O, ErCl3·6H2O, oleic acid, NaF, PEI, europium chloride, TTA, sodium hydroxide. Deionized water and ethanol are also required during the preparation process. The molecular weight of PEI is 60,000.

[0060] In this example, the preparation method of the dual-fluorescent anti-counterfeiting fiber of plant-based upconversion and downconversion materials is as follows:

[0061] (1) One-step preparation of NaYF4:Yb,Er upconversion material by hydrothermal method: After mixing 0.936 mL of 0.2 mol / L YCl3 solution, 0.24 mL of 0.2 mol / L YbCl3 solution, and 0.24 mL of 0.02 mol / L ErCl3 solution, add them to the mixed solution of NaF solution, NaOH solution, oleic acid, and ethanol solution, mix evenly, keep warm at 160 °C - 200 °C for 8 h - 12 h, wash with ethanol and centrifuge after cooling, vacuum dry the precipitate at 60 °C for 12 h, and obtain the NaYF4:Yb,Er upconversion material after grinding;

[0062] (2) Weigh 0.1 g of PEI and dissolve it in 10 mL, and disperse 0.02 g of the NaYF4:Yb,Er upconversion material obtained in step (1) evenly in the PEI aqueous solution;

[0063] (3) Disperse the plant fiber pulp containing 1 g of absolute dry Chinese alpine rush fiber in 2000 ml of water to form an aqueous suspension, and add 5 mL of 6 mmol / L EuCl3 solution and 15 mL of 6 mmol / L TTA dropwise to the suspension, adjust the pH to 7 with NaOH solution, and react for 60 min;

[0064] (4) Slowly add the NaYF4:Yb,Er solution obtained in step (2) dropwise to the fiber suspension obtained in step (3), stir for 30 min, and then stop the reaction;

[0065] (5) Finally, after washing three times repeatedly with deionized water, suction filtration, and drying at 60 °C for 12 h, the dual-fluorescent anti-counterfeiting fiber of plant-based upconversion and downconversion materials is obtained.

[0066] Example 5

[0067] In this embodiment, the raw materials and reagents for preparing the dual-fluorescence anti-counterfeiting fibers of plant-based upconversion and downconversion materials include: natural-color Chinese fir fiber pulp with a beating degree of 13°SR, YCl3·6H2O, YbCl3·6H2O, ErCl3·6H2O, oleic acid, NaF, PEI, europium chloride, TTA, sodium hydroxide. Deionized water and ethanol are also required during the preparation process. The molecular weight of PEI is 1800.

[0068] In this embodiment, the preparation method of the dual-fluorescence anti-counterfeiting fibers of plant-based upconversion and downconversion materials is as follows:

[0069] (1) Prepare the NaYF4:Yb,Er upconversion material by a one-step hydrothermal method: After mixing 0.936 mL of 0.2 mol / L YCl3 solution, 0.24 mL of 0.2 mol / L YbCl3 solution, and 0.24 mL of 0.02 mol / L ErCl3 solution, add them to the mixed solution of NaF solution, NaOH solution, oleic acid, and ethanol solution, mix evenly, keep warm at 160 °C - 200 °C for 8 h - 12 h, wash with ethanol and centrifuge after cooling, vacuum dry the precipitate at 60 °C for 12 h, and obtain the NaYF4:Yb,Er upconversion material after grinding;

[0070] (2) Weigh 1 g of PEI with a molecular weight of 1800 and dissolve it in 15 mL of water, and evenly disperse 0.02 g of the NaYF4:Yb,Er upconversion material obtained in step (1) in the PEI aqueous solution;

[0071] (3) Disperse the plant fiber pulp containing 1 g of absolute dry Chinese fir fiber in 2000 ml of water to form an aqueous suspension, and add 5 mL of 6 mmol / L EuCl3 solution and 15 mL of 6 mmol / L TTA dropwise to the suspension, adjust the pH to 7 with NaOH solution, and react for 60 min;

[0072] (4) Gradually add the NaYF4:Yb,Er solution obtained in step (2) dropwise to the fiber suspension obtained in step (3), stir for 30 min, and stop the reaction;

[0073] (5) Finally, obtain the dual-fluorescence anti-counterfeiting fibers of plant-based upconversion and downconversion materials after washing three times repeatedly with deionized water, suction filtration, and drying at 60 °C for 12 h.

[0074] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly explaining the present invention, and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is impossible to list all the implementation manners here. Any obvious changes or variations derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. A preparation method of a dual-fluorescence anti-counterfeiting fiber of a plant-based up-conversion and down-conversion material, characterized in that, It includes the following steps: S1. Uniformly disperse the NaYF4:Yb,Er upconversion material in the PEI solution; the molecular weight of the PEI is 1800 - 100000; S2. Prepare the plant fiber into an aqueous suspension, add an europium chloride solution and a TTA solution dropwise to the suspension, and then adjust the pH to 6 - 8, and react for 30 - 90 min; S3. Add the NaYF4:Yb,Er solution obtained in S1 to the solution obtained in S2 and react for 10 - 60 min; S4. After washing, suction filtration and vacuum drying, a dual - fluorescence anti - counterfeiting fiber of plant - based up - conversion and down - conversion materials is obtained.

2. The preparation method of the dual-fluorescence anti-counterfeiting fiber of the plant-based upconversion and downconversion material according to claim 1, characterized in that, The weight ratio of each raw material is: 30 - 95% of plant fiber, 1 - 15% of NaYF4:Yb,Er upconversion material, 1% - 15% of europium chloride, and 1 - 45% of TTA.

3. The preparation method of the dual-fluorescence anti-counterfeiting fiber of the plant-based up-conversion and down-conversion material according to claim 1, characterized in that The NaYF4:Yb,Er upconversion material in S1 is prepared in one step by a hydrothermal method, including the following steps: Mix the inorganic salt solutions containing Y, Yb, and Er, NaOH solution, oleic acid, ethanol solution, and NaF solution evenly, keep the temperature at 160°C - 200°C for 8 h - 12 h, cool, wash, dry, and grind to obtain the NaYF4:Yb,Er upconversion material; the molar ratio of Y, Yb, and Er metal ions in the inorganic salt solutions of Y, Yb, and Er is 75% - 80%:18% - 24%:1% - 2%.

4. The preparation method of the dual-fluorescent fiber of the plant-based upconversion and downconversion material according to claim 3, characterized in that, The inorganic salt solutions of Y, Yb, and Er are chloride salt solutions; the molar ratio of Y, Yb, and Er metal ions is 78%:20%:2%.

5. The preparation method of the dual-fluorescence anti-counterfeiting fiber of the plant-based upconversion and downconversion material according to claim 1, characterized in that, In S2, the concentration of the europium chloride solution is 1 mmol / L - 15 mmol / L, the TTA solution is 3 mmol / L - 45 mmol / L, and the molar ratio of the two is 1:3; the pH value in S2 is 7, and the reaction time is 60 min; the reaction time in S3 is 30 min.

6. The preparation method of the dual-fluorescent fiber of the plant-based up-conversion and down-conversion material according to claim 1, characterized in that, In S4, it is washed 3 times with deionized water, the vacuum drying temperature is 40 - 80°C, and the vacuum drying time is 12 h.

7. The preparation method of the dual-fluorescent fiber of the plant-based upconversion and downconversion material according to any one of claims 1-6, characterized in that, The molecular weight of the PEI is 60000.

8. The preparation method of the dual-fluorescent fiber of the plant-based up-conversion and down-conversion material according to claim 7, characterized in that, The plant fiber is one or more of wood fiber, bamboo fiber, cotton fiber, hemp fiber, palm fiber, grass fiber, and bast fiber; the beating degree of the plant fiber is 13 - 75°SR.

9. The dual - fluorescence anti - counterfeiting fiber of plant - based up - conversion and down - conversion materials prepared by the method according to any one of claims 1 - 8.

10. Use of the dual-fluorescence anti-counterfeiting fiber made of the plant-based upconversion and downconversion materials according to claim 9, characterized in that, It is applied to the field of anti - counterfeiting fibers.

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