A polylactic acid fluorescent anti-counterfeiting fiber and a preparation method thereof

Abstract

The application provides an organic-inorganic hybrid crystal material and a preparation method thereof. The application also provides a preparation method of polylactic acid fluorescent anti-counterfeiting fiber. The triclinic organic-inorganic hybrid crystal material has specific cell parameters, small birefringence, and can emit green light with a peak value of 542 nm, which is very beneficial to application in the fluorescent anti-counterfeiting field. The application also provides a corresponding preparation method. The colorless and transparent crystal material is grown by using a water solution method, the process is simple, the yield is high, and the crystal material with high purity and high crystallinity can be obtained. The organic-inorganic hybrid fluorescent anti-counterfeiting fiber prepared by the application is randomly arranged, the diameter of the fiber is uniformly distributed, the surface of the fiber is smooth, the diameter of the fiber is about 0.7-1.2 microns, the thermal stability temperature of the polylactic acid fluorescent anti-counterfeiting fiber can reach 167 DEG C, and the strongest emission wavelength of the polylactic acid fluorescent anti-counterfeiting fiber is 542 nm.

Description

Technical Field

[0001] This invention belongs to the technical field of polylactic acid fluorescent anti-counterfeiting fiber materials, and relates to an organic-inorganic hybrid crystal material and its preparation method and application, as well as a polylactic acid fluorescent anti-counterfeiting fiber and its preparation method. In particular, it relates to an organic-inorganic hybrid crystal material and its preparation method and application, as well as a polylactic acid fluorescent anti-counterfeiting fiber based on a novel hybrid fluorescent material and its preparation method. Background Technology

[0002] Anti-counterfeiting fibers, as a rising star in anti-counterfeiting technology products, are widely used in papermaking, textiles, and handicrafts due to their lightweight, easy-to-process characteristics and adjustability in attributes such as length, diameter, and color. In recent years, the proliferation of counterfeit and substandard products has permeated all aspects of daily life, prompting greater attention to the development of anti-counterfeiting technology, with fluorescent anti-counterfeiting fibers being the most prominent. The rapid development of synthetic polymer materials has consumed limited petroleum resources and led to environmental pollution, resulting in increasing emphasis on green, environmentally friendly, and biodegradable polylactic acid (PLA) fibers.

[0003] Currently, researchers both domestically and internationally have successfully prepared polylactic acid fibers with antibacterial, flame-retardant, and hydrophilic properties. However, most of the matrix materials of the fluorescent anti-counterfeiting fibers currently available are petroleum-based polymers, and there are very few fluorescent anti-counterfeiting fibers using bio-based polymers such as polylactic acid as the matrix material.

[0004] Therefore, further development of polylactic acid fluorescent anti-counterfeiting fibers, utilizing the excellent transparency and UV resistance of polylactic acid fibers, will enable them to have better concealment and broader application space in the anti-counterfeiting field. This will have a positive promoting effect on improving the added value of polylactic acid fibers and expanding the depth and breadth of their application fields, and is also one of the focuses of attention for many front-line researchers in the industry. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide an organic-inorganic hybrid crystal material and its preparation method, as well as its application, and a polylactic acid fluorescent anti-counterfeiting fiber and its preparation method, particularly a polylactic acid fluorescent anti-counterfeiting fiber based on a novel hybrid fluorescent material and its preparation method. The present invention provides a specific organic-inorganic hybrid crystal material, which is then combined with pure polylactic acid to prepare polylactic acid fluorescent anti-counterfeiting fiber, thereby improving the fluorescent performance of the fiber. Furthermore, the preparation method involves simple synthesis steps, mild conditions, and emphasized controllability, making it suitable for large-scale production, promotion, and application.

[0006] This invention provides an organic-inorganic hybrid crystal material, the chemical formula of which is (C5H6NO). + (H2PO4) -;

[0007] The crystalline material belongs to the triclinic crystal system and has a space group of P-1.

[0008] Preferably, the crystal material is a fluorescent crystal material;

[0009] The fluorescence is specifically a fluorescent crystal that emits green light;

[0010] The unit cell parameters of the crystal material are: α = 102.827(6)°, β = 100.129(5)°, γ = 112.781(6)°, Z = 2, unit cell volume

[0011] Preferably, the organic group of the crystal material is 2-hydroxypyridine, and the anionic portion is dihydrogen phosphate ion;

[0012] The crystalline material has a transmittance of greater than 70% in the 330–2600 nm spectral range;

[0013] The ultraviolet absorption cutoff wavelength of the crystal material is 330 nm.

[0014] The crystal material includes crystal materials used in polylactic acid fluorescent anti-counterfeiting fibers.

[0015] This invention provides a method for preparing an organic-inorganic hybrid crystal material as described in any of the above technical solutions, comprising the following steps:

[0016] A mixture of 2-hydroxypyridine, phosphoric acid or a compound containing dihydrogen phosphate, and water is obtained. The mixture is then heated and cooled to crystallize, yielding an organic-inorganic hybrid crystal material.

[0017] Preferably, the compound containing dihydrogen phosphate is selected from one or more of phosphoric acid, lithium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, and rubidium dihydrogen phosphate;

[0018] The molar ratio of the 2-hydroxypyridine to phosphoric acid or a compound containing dihydrogen phosphate is (0.01–1):(0.01–1).

[0019] The molar volume ratio of 2-hydroxypyridine to water is (0.01–1) mol: (2–200) mL;

[0020] The heating temperature is 40–100°C;

[0021] The heating time is until the volume of the mixture is reduced to 45% to 95% of its initial volume.

[0022] This invention provides the application of the organic-inorganic hybrid crystal material described in any one of the above technical solutions or the organic-inorganic hybrid crystal material prepared by the preparation method described in any one of the above technical solutions in polylactic acid fluorescent anti-counterfeiting fibers.

[0023] This invention provides a polylactic acid fluorescent anti-counterfeiting fiber, wherein the polylactic acid fluorescent anti-counterfeiting fiber contains a fluorescent polycrystalline material;

[0024] The fluorescent polycrystalline material includes the organic-inorganic hybrid crystal material described in any one of the above technical solutions or the organic-inorganic hybrid crystal material prepared by any one of the above technical solutions.

[0025] Preferably, the fluorescent polycrystalline material is an organic-inorganic hybrid crystal material-based composite material;

[0026] The fluorescent polycrystalline material includes an organic-inorganic hybrid crystal material and a titanate coupling agent composited on the surface of the organic-inorganic hybrid crystal material;

[0027] The mass ratio of the titanate coupling agent to the organic-inorganic hybrid crystal material is (2-5):100;

[0028] In the polylactic acid fluorescent anti-counterfeiting fiber, the mass content of the fluorescent polycrystalline material is 1% to 10%.

[0029] The present invention also provides a method for preparing polylactic acid fluorescent anti-counterfeiting fibers as described in any one of the above technical solutions, comprising the following steps:

[0030] 1) The organic-inorganic hybrid crystal material, titanate coupling agent and solvent are mixed, and after being allowed to stand under vacuum, the solvent is removed to obtain fluorescent polycrystalline material powder.

[0031] 2) The fluorescent polycrystalline material powder obtained in the above steps is extruded with polylactic acid to obtain polylactic acid fluorescent masterbatch. Then, the polylactic acid fluorescent masterbatch and polylactic acid are melt-spun to obtain polylactic acid fluorescent anti-counterfeiting fiber.

[0032] Preferably, the temperature for vacuum settling is 80–120°C;

[0033] The vacuum settling time is 1 to 3 hours;

[0034] The mass content of the polycrystalline fluorescent material in the polylactic acid fluorescent masterbatch is 5% to 20%.

[0035] The melt spinning temperature is 210–230°C.

[0036] This invention provides an organic-inorganic hybrid crystal material, the chemical formula of which is (C5H6NO).+ (H2PO4) - The crystal material belongs to the triclinic crystal system and has a space group of P-1. Compared with the prior art, this invention creatively obtains a triclinic organic-inorganic hybrid crystal material with specific properties, specific unit cell parameters, and a small birefringence. Furthermore, this organic-inorganic hybrid crystal material can emit green light with a peak value of 542 nm, which is highly advantageous for application in the field of fluorescent anti-counterfeiting.

[0037] The organic-inorganic hybrid fluorescent crystal material (C5H6NO) provided by this invention + (H2PO4) - The birefringence at 800 nm is 0.16. The birefringent crystal material (C5H6NO) provided by this invention... + (H2PO4) - It exhibits a transmittance of over 70% in the 330–2600 nm spectral range, demonstrating high transmittance. This invention also provides a birefringent crystal material (C5H6NO). + (H2PO4) - The preparation method employed an aqueous solution method to grow colorless and transparent (C5H6NO). + (H2PO4) - Crystals. This method is simple, has a high yield, and can produce high-purity, highly crystalline (C5H6NO). + (H2PO4) - Crystalline materials.

[0038] This invention pretreats the crystalline material and blends it with polylactic acid chips for melt spinning to obtain polylactic acid fluorescent anti-counterfeiting fiber. This organic-inorganic hybrid fluorescent anti-counterfeiting fiber is randomly arranged with a uniform diameter distribution and a smooth surface. Its diameter is approximately 0.7–1.2 μm. The thermal stability temperature of the polylactic acid fluorescent anti-counterfeiting fiber can reach 167°C. The strongest emission wavelength of the polylactic acid fluorescent anti-counterfeiting fiber containing organic-inorganic hybrid fluorescent crystal material is 542 nm. Attached Figure Description

[0039] Figure 1 (C5H6NO) prepared in Example 1 of this invention. + (H2PO4) - Schematic diagram of crystal structure;

[0040] Figure 2 (C5H6NO) prepared in Example 1 of this invention. + (H2PO4) - XRD pattern of the crystal.

[0041] Figure 3This is a scanning electron microscope image of the polylactic acid fluorescent anti-counterfeiting fiber prepared in Example 1 of the present invention;

[0042] Figure 4 The differential thermal curve of the polylactic acid fluorescent anti-counterfeiting fiber prepared in Example 1 of this invention;

[0043] Figure 5 The fluorescence spectrum of the polylactic acid fluorescent anti-counterfeiting fiber prepared in Example 1 of this invention is shown below.

[0044] Figure 6 This is a laser confocal fluorescence distribution map of the polylactic acid fluorescent anti-counterfeiting fiber prepared in Example 1 of the present invention. Detailed Implementation

[0045] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims.

[0046] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0047] The purity of the raw materials used in this invention is not particularly limited. Preferably, the purity is analytical grade or conventional in the field of polylactic acid fluorescent anti-counterfeiting fiber preparation.

[0048] All raw materials of this invention are conventional in the field, and each brand name and abbreviation is clear and distinct in its relevant application. Those skilled in the art can purchase them from the market or prepare them by conventional methods based on the brand name, abbreviation and corresponding application.

[0049] All processes in this invention are referred to by abbreviations that are common abbreviations in the field. Each abbreviation is clear and specific in its relevant application area, and those skilled in the art can understand its conventional process steps based on the abbreviation.

[0050] This invention provides an organic-inorganic hybrid crystal material, the chemical formula of which is (C5H6NO). + (H2PO4) - ;

[0051] The crystalline material belongs to the triclinic crystal system and has a space group of P-1.

[0052] In this invention, the crystal material is preferably a fluorescent crystal material.

[0053] In this invention, the fluorescent material is preferably a fluorescent crystal that emits green light.

[0054] In this invention, the unit cell parameters of the crystal material are: α = 102.827(6)°, β = 100.129(5)°, γ = 112.781(6)°, Z = 2, unit cell volume

[0055] In this invention, the organic group of the crystal material is preferably 2-hydroxypyridine, and the anionic portion is preferably dihydrogen phosphate ion.

[0056] In this invention, the transmittance of the crystal material in the 330-2600 nm spectral range is preferably greater than 70%, more preferably greater than 75%, and even more preferably greater than 80%.

[0057] In this invention, the ultraviolet absorption cutoff wavelength of the crystal material is preferably 330 nm.

[0058] In this invention, the crystal material preferably includes a crystal material used for polylactic acid fluorescent anti-counterfeiting fibers.

[0059] Compared to existing similar crystalline materials, the organic-inorganic hybrid crystalline material prepared in this invention has completely different specific unit cell parameters, which fundamentally determines that the organic-inorganic hybrid crystalline material in this invention is a different substance from other similar crystalline materials. At the same time, this organic-inorganic hybrid crystalline material also has its specific properties: it has a low birefringence, and its strongest emission wavelength is located at 542nm. It can emit green light and has high fluorescence intensity. Moreover, the human eye is more sensitive to green light, which is very advantageous for application in the field of fluorescent anti-counterfeiting. In contrast, similar birefringent crystals emit relatively weak blue fluorescence under the same conditions, which is not conducive to human judgment and identification, and is therefore unfavorable for the field of fluorescent anti-counterfeiting.

[0060] This invention provides a method for preparing an organic-inorganic hybrid crystal material as described in any of the above technical solutions, comprising the following steps:

[0061] A mixture of 2-hydroxypyridine, phosphoric acid or a compound containing dihydrogen phosphate, and water is obtained. The mixture is then heated and cooled to crystallize, yielding an organic-inorganic hybrid crystal material.

[0062] In this invention, the compound containing dihydrogen phosphate is preferably selected from one or more of phosphoric acid, lithium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, and rubidium dihydrogen phosphate, and more preferably phosphoric acid, lithium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, or rubidium dihydrogen phosphate.

[0063] In this invention, the molar ratio of the 2-hydroxypyridine to phosphoric acid or a compound containing dihydrogen phosphate is preferably (0.01-1):(0.01-1), more preferably (0.1-0.7):(0.1-0.7), and even more preferably (0.2-0.4):(0.2-0.4).

[0064] In this invention, the molar volume ratio of 2-hydroxypyridine to water is preferably (0.01-1) mol:(2-200) mL, more preferably (0.1-0.7) mol:(20-150) mL, and even more preferably (0.2-0.4) mol:(70-100) mL.

[0065] In this invention, the heating temperature is preferably 40-100°C, more preferably 50-90°C, and even more preferably 60-80°C.

[0066] In this invention, the heating time is such that the volume of the mixture is reduced to 45% to 95% of the initial volume of the mixture, more preferably 55% to 85%, and even more preferably 65% ​​to 75%.

[0067] This invention provides the application of the organic-inorganic hybrid crystal material described in any one of the above technical solutions or the organic-inorganic hybrid crystal material prepared by the preparation method described in any one of the above technical solutions in polylactic acid fluorescent anti-counterfeiting fibers.

[0068] This invention provides a polylactic acid fluorescent anti-counterfeiting fiber, wherein the polylactic acid fluorescent anti-counterfeiting fiber contains a fluorescent polycrystalline material;

[0069] The fluorescent polycrystalline material includes the organic-inorganic hybrid crystal material described in any one of the above technical solutions or the organic-inorganic hybrid crystal material prepared by any one of the above technical solutions.

[0070] In this invention, the fluorescent polycrystalline material is preferably an organic-inorganic hybrid crystal material-based composite material.

[0071] In this invention, the fluorescent polycrystalline material preferably includes an organic-inorganic hybrid crystal material and a titanate coupling agent composited on the surface of the organic-inorganic hybrid crystal material.

[0072] In this invention, the mass ratio of the titanate coupling agent to the organic-inorganic hybrid crystal material is preferably (2-5):100, more preferably (2.5-4.5):100, and even more preferably (3-4):100.

[0073] In this invention, the polylactic acid fluorescent anti-counterfeiting fiber preferably contains 1% to 10% by mass, more preferably 3% to 8%, and even more preferably 5% to 6% by mass.

[0074] This invention provides a method for preparing polylactic acid fluorescent anti-counterfeiting fiber according to any one of the above technical solutions, comprising the following steps:

[0075] 1) The organic-inorganic hybrid crystal material, titanate coupling agent and solvent are mixed, and after being allowed to stand under vacuum, the solvent is removed to obtain fluorescent polycrystalline material powder.

[0076] 2) The fluorescent polycrystalline material powder obtained in the above steps is extruded with polylactic acid to obtain polylactic acid fluorescent masterbatch. Then, the polylactic acid fluorescent masterbatch and polylactic acid are melt-spun to obtain polylactic acid fluorescent anti-counterfeiting fiber.

[0077] The present invention first mixes organic-inorganic hybrid crystal material, titanate coupling agent and solvent, and after vacuum standing, removes the solvent to obtain fluorescent polycrystalline material powder.

[0078] In this invention, the temperature of the vacuum settling is preferably 80-120°C, more preferably 88-112°C, and even more preferably 96-104°C.

[0079] In this invention, the vacuum settling time is preferably 1 to 3 hours, more preferably 1.4 to 2.6 hours, and even more preferably 1.8 to 2.2 hours.

[0080] The present invention further extrudes the fluorescent polycrystalline material powder obtained in the above steps with polylactic acid to obtain polylactic acid fluorescent masterbatch, and then melt spins the polylactic acid fluorescent masterbatch and polylactic acid to obtain polylactic acid fluorescent anti-counterfeiting fiber.

[0081] In this invention, the mass content of the polycrystalline fluorescent material in the polylactic acid fluorescent masterbatch is preferably 5% to 20%, more preferably 8% to 17%, and even more preferably 11% to 14%.

[0082] In this invention, the temperature of the melt spinning is preferably 210-230°C, more preferably 214-226°C, and even more preferably 218-222°C.

[0083] This invention aims to complete and refine the overall technical solution, better guarantee the structure and properties of the organic-inorganic hybrid crystal material and the polylactic acid fluorescent anti-counterfeiting fiber, and further improve the fluorescence performance of the organic-inorganic hybrid crystal material and the anti-counterfeiting performance of the polylactic acid fluorescent anti-counterfeiting fiber. Specifically, the aforementioned organic-inorganic hybrid crystal material and its preparation method, and the polylactic acid fluorescent anti-counterfeiting fiber and its preparation method, may include the following:

[0084] A method for preparing polylactic acid fluorescent anti-counterfeiting fiber includes the following steps:

[0085] 1) Preparation of an organic-inorganic hybrid fluorescent material (C5H6NO) + (H2PO4) - .

[0086] The crystalline material is obtained by mixing 2-hydroxypyridine, phosphoric acid or a compound containing dihydrogen phosphate, and water using an aqueous solution method, heating the mixture, and then cooling it to crystallize.

[0087] 2) Pretreatment of organic-inorganic hybrid fluorescent crystal materials.

[0088] The fluorescent material obtained in step 1) was placed in a beaker, and an appropriate amount of ethanol was used to immerse the fluorescent material. Then, a mixture of titanate coupling agent and ethanol was added. The mixture was magnetically stirred at room temperature to make the titanate coupling agent uniformly dispersed on the surface of the phosphor. The mixture was kept under vacuum heating for 2 hours. After evaporating the ethanol, the pretreated polycrystalline fluorescent material powder was obtained.

[0089] 3) Preparation of polylactic acid fluorescent anti-counterfeiting fiber.

[0090] First, a polylactic acid fluorescent masterbatch containing a certain amount of fluorescent material polycrystalline powder is prepared using a twin-screw extruder. The polylactic acid fluorescent masterbatch and pure polylactic acid are then dried for later use. Next, melt spinning is performed to prepare polylactic acid fluorescent anti-counterfeiting fibers with a mass fraction of 1% to 10%. Finally, the nascent fibers are stretched using a parallel stretching machine to obtain the polylactic acid fluorescent anti-counterfeiting fibers.

[0091] Specifically, the chemical formula of the crystalline material is (C5H6NO). + (H2PO4) - The molecular weight is 193.09; the crystal material belongs to the triclinic crystal system and the space group is P-1.

[0092] Specifically, the crystal material is (C5H6NO). + (H2PO4) - Its unit cell parameters are: α = 102.827(6)°, β = 100.129(5)°, γ = 112.781(6)°, Z = 2, unit cell volume

[0093] Specifically, the (C5H6NO) + (H2PO4) - Crystalline materials have the following properties: Figure 1 The crystal structure shown.

[0094] See Figure 1 , Figure 1 (C5H6NO) prepared in Example 1 of this invention. + (H2PO4) -A schematic diagram of the crystal structure.

[0095] Specifically, the (C5H6NO) + (H2PO4) - Crystalline materials have basic properties such as Figure 2 The XRD pattern shown.

[0096] See Figure 2 , Figure 2 (C5H6NO) prepared in Example 1 of this invention. + (H2PO4) - XRD pattern of the crystal.

[0097] Specifically, its crystal structure contains [C5H6NO]. + With [H2PO4] - The groups are arranged alternately, with each adjacent [C5H6NO] group... + With [H2PO4] - The groups are connected by hydrogen bonds (OH…O and NH…O).

[0098] Specifically, the crystalline material has a birefringence of 0.16 at 800 nm.

[0099] Specifically, the crystalline material has a transmittance of greater than 70% in the 330-2600nm spectral range.

[0100] Specifically, the ultraviolet absorption cutoff wavelength of the crystal material is 330 nm.

[0101] Specifically, the crystal material is a colorless and transparent crystal.

[0102] Specifically, the molar volume ratio of the 2-hydroxypyridine, phosphoric acid, or compound containing dihydrogen phosphate to water is (0.01-1) mol:(0.01-1) mol:(2-200) mL.

[0103] Specifically, the heating temperature is 40-100℃;

[0104] Specifically, the degree of heating is until the volume of the mixture is reduced to 45-95% of its initial volume;

[0105] Specifically, the phosphoric acid or compound containing dihydrogen phosphate can be selected from at least one of phosphoric acid, lithium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, rubidium dihydrogen phosphate, etc.

[0106] Furthermore, the preparation method of polylactic acid fluorescent anti-counterfeiting fiber provided by the present invention includes the following steps:

[0107] 1) Prepare an organic-inorganic hybrid fluorescent material.

[0108] The organic-inorganic hybrid fluorescent crystal material provided by this invention has the chemical formula (C5H6NO). + (H2PO4) - It is represented by a molecular weight of 193.09, in which the organic group is 2-hydroxypyridine, the molecular formula is C5H5NO, and the structural formula is as follows; the anionic part is dihydrogen phosphate ion.

[0109]

[0110] The crystalline material belongs to the triclinic crystal system and has a space group of P-1.

[0111] Specifically, the crystalline material (C5H6NO) + (H2PO4) - It has a transmittance of over 70% in the 330–2600 nm spectral range, exhibiting high transmittance.

[0112] Specifically, the crystalline material is a colorless and transparent crystal, and the polycrystalline powder is a white powder.

[0113] The present invention also provides a method for preparing the above-mentioned crystal material, which uses an aqueous solution method, wherein 2-hydroxypyridine, phosphoric acid or a compound containing dihydrogen phosphate, and water are mixed and heated, and then cooled to crystallize, thereby obtaining the crystal material with a yield greater than 90%.

[0114] Specifically, the molar volume ratio of the 2-hydroxypyridine, phosphoric acid, or a compound containing dihydrogen phosphate to water is (0.01-1) mol:(0.01-1) mol:(2-200) mL. Preferably, the molar volume ratio is (0.01-0.5) mol:(0.01-0.5) mol:(2-100) mL. Exemplarily, the molar volume ratio is 0.02 mol:0.02 mol:20 mL or 0.04 mol:0.04 mol:40 mL.

[0115] Specifically, the heating temperature is 40–100°C, for example, 60–100°C; exemplarily, the temperature can be 70°C or 90°C. Preferably, the degree of heating is until the volume of the mixture is reduced to 45–95% of the initial volume, for example, 50–90%; exemplarily, the heating is until the volume of the mixture is reduced to 60% or 90% of the initial volume.

[0116] Specifically, the phosphoric acid or compound containing dihydrogen phosphate can be selected from at least one of phosphoric acid, lithium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, rubidium dihydrogen phosphate, etc. Preferably, the phosphoric acid or compound containing dihydrogen phosphate can be selected from at least one of phosphoric acid, lithium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate. Exemplarily, the phosphoric acid or compound containing dihydrogen phosphate can be selected from phosphoric acid and potassium dihydrogen phosphate.

[0117] 2) Pretreatment of organic-inorganic hybrid fluorescent crystal materials.

[0118] The fluorescent material obtained in step 1) was placed in a beaker, and an appropriate amount of ethanol was used to immerse the fluorescent material. Then, a mixture of titanate coupling agent and ethanol (mass ratio 1 / 3) with a mass fraction w = 2% was added. The mixture was magnetically stirred (300 r / min) at room temperature for 1 h to make the titanate coupling agent uniformly dispersed on the surface of the phosphor. The mixture was kept under vacuum (-0.1 MPa) at 120 °C for 2 h. After evaporating the ethanol, the pretreated polycrystalline fluorescent material powder was obtained.

[0119] 3) Preparation of polylactic acid fluorescent anti-counterfeiting fiber.

[0120] First, a polylactic acid (PLA) fluorescent masterbatch with a mass fraction of 15% polycrystalline powder was prepared using a twin-screw extruder. The PLA fluorescent masterbatch and pure PLA chips were then dried at 120°C for 24 hours. Next, melt spinning was performed to prepare PLA fluorescent anti-counterfeiting fibers with a mass fraction of 1% to 10%. The spinneret orifice diameter was 0.4 mm, the spinning temperature was 210–230°C, and the winding rate was 600 m / min. Finally, the nascent fibers were stretched using a parallel stretching machine at a hot plate temperature of 50°C and a stretching ratio of 3 times. The resulting PLA fluorescent anti-counterfeiting fiber was then obtained.

[0121] Furthermore, the method of the present invention also includes step 4) detection, analysis and characterization; specifically, the morphology, fluorescence properties and thermal stability of the prepared polylactic acid fluorescent anti-counterfeiting fiber are detected, analyzed and characterized.

[0122] Morphological analysis of polylactic acid fluorescent anti-counterfeiting fibers was performed using scanning electron microscopy.

[0123] The thermal stability of polylactic acid fluorescent anti-counterfeiting fiber was analyzed using a thermogravimetric analyzer.

[0124] The fluorescence properties of polylactic acid fluorescent anti-counterfeiting fibers were analyzed using a fluorescence spectrometer.

[0125] The distribution of fluorescent particles in polylactic acid fluorescent anti-counterfeiting fibers was analyzed using laser confocal microscopy.

[0126] This invention provides a method for preparing polylactic acid fluorescent anti-counterfeiting fibers, belonging to the technical field of fluorescent anti-counterfeiting fibers. The method includes: 1) preparing an organic-inorganic hybrid fluorescent material (C5H6NO). + (H2PO4) - Its crystal structure is triclinic, space group P-1, and its unit cell parameters are: α = 102.827(6)°, β = 100.129(5)°, γ = 112.781(6)°, Z = 2, unit cell volume 2) Pretreatment of the organic-inorganic hybrid fluorescent material; 3) Melt spinning preparation of polylactic acid fluorescent anti-counterfeiting fiber. This invention prepares the organic-inorganic hybrid compound crystal material (C5H6NO) using phosphoric acid and 2-hydroxypyridine. + (H2PO4) - Then, after pretreatment with a titanate coupling agent and ethanol, polylactic acid fluorescent anti-counterfeiting fibers were prepared by melt spinning technology using organic-inorganic hybrid fluorescent materials and pure polylactic acid, thus improving the fluorescent performance of the fibers. This invention prepares organic-inorganic hybrid fluorescent materials (C5H6NO) through specific process steps and parameters. + (H2PO4) - Furthermore, only by using this process step and parameters can the organic-inorganic hybrid fluorescent material (C5H6NO) be prepared. + (H2PO4) - Only by employing the above-mentioned melt spinning technology can polylactic acid fluorescent anti-counterfeiting fibers be prepared; and only by using the above-mentioned melt spinning conditions and steps can the aforementioned organic-inorganic hybrid fluorescent material (C5H6NO) be successfully produced. + (H2PO4) - It is processed into polylactic acid fluorescent anti-counterfeiting fiber.

[0127] The organic-inorganic hybrid fluorescent anti-counterfeiting fiber prepared by this invention is randomly arranged with a uniform diameter distribution and a smooth surface. Its diameter is about 0.7 to 1.2 μm. The thermal stability temperature of the polylactic acid fluorescent anti-counterfeiting fiber can reach 167℃. The strongest emission wavelength of the polylactic acid fluorescent anti-counterfeiting fiber containing organic-inorganic hybrid fluorescent crystal material is 542 nm.

[0128] The present invention provides an organic-inorganic hybrid crystal material, its preparation method, and its application, as well as a polylactic acid fluorescent anti-counterfeiting fiber based on a novel hybrid fluorescent material and its preparation method. The present invention yields a triclinic organic-inorganic hybrid crystal material with specific properties, including specific unit cell parameters. Furthermore, this organic-inorganic hybrid crystal material exhibits a low birefringence and emits green light with a peak wavelength of 542 nm, making it highly advantageous for application in the field of fluorescent anti-counterfeiting.

[0129] The organic-inorganic hybrid fluorescent crystal material (C5H6NO) provided by this invention + (H2PO4) - The birefringence at 800 nm is 0.16. The birefringent crystal material (C5H6NO) provided by this invention... + (H2PO4) - It exhibits a transmittance of over 70% in the 330–2600 nm spectral range, demonstrating high transmittance. This invention also provides a birefringent crystal material (C5H6NO). + (H2PO4) - The preparation method employed an aqueous solution method to grow colorless and transparent (C5H6NO). + (H2PO4) - Crystals. This method is simple, has a high yield, and can produce high-purity, highly crystalline (C5H6NO). + (H2PO4) - Crystalline materials.

[0130] This invention pretreats the crystalline material and blends it with polylactic acid chips for melt spinning to obtain polylactic acid fluorescent anti-counterfeiting fiber. This organic-inorganic hybrid fluorescent anti-counterfeiting fiber is randomly arranged with a uniform diameter distribution and a smooth surface. Its diameter is approximately 0.7–1.2 μm. The thermal stability temperature of the polylactic acid fluorescent anti-counterfeiting fiber can reach 167°C. The strongest emission wavelength of the polylactic acid fluorescent anti-counterfeiting fiber containing organic-inorganic hybrid fluorescent crystal material is 542 nm.

[0131] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, describes an organic-inorganic hybrid crystal material and its preparation method, its application, and a polylactic acid fluorescent anti-counterfeiting fiber and its preparation method. However, it should be understood that these embodiments are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating procedures. They are only for further illustrating the features and advantages of the present invention, and are not intended to limit the scope of the claims of the present invention. The scope of protection of the present invention is not limited to the following embodiments.

[0132] Example 1

[0133] 1) Prepare an organic-inorganic hybrid fluorescent material.

[0134] 11) Dissolve 0.02 mol of 2-hydroxypyridine and 0.02 mol of phosphoric acid in 20 mL of water;

[0135] 12) Place the beaker containing the mixed aqueous solution from step 11) on a magnetic stirrer and heat it to 100 degrees Celsius while stirring continuously until the solution is concentrated to 10 mL. Then cool and crystallize. Three days later, a large number of colorless and transparent single crystals appear, with a yield of more than 90%.

[0136] 13) Place the crystals obtained in step 12) in a desiccator to allow moisture to evaporate naturally. Perform XRD tests on the obtained crystals. The X-ray diffraction pattern of the product prepared by the method in this embodiment is as follows: Figure 2 As shown.

[0137] The (C5H6NO) obtained in this embodiment + (H2PO4) - The crystal structure of organic-inorganic hybrid birefringent crystals is as follows: Figure 1 As shown, its crystal structure diagram is a projection along the a-axis direction, and its crystal structure contains [C5H6NO]. + With [H2PO4] - The groups are arranged alternately, with adjacent [C5H6NO] groups. + With [H2PO4] - The groups are connected by hydrogen bonds (OH…O and NH…O).

[0138] First-principles calculations show that the crystal in this embodiment has a large birefringence: 0.16 at 800 nm.

[0139] The crystal material obtained in this embodiment has a transmittance of greater than 70% in the 330-2600nm spectral range.

[0140] The ultraviolet absorption cutoff wavelength of the crystal material obtained in this embodiment is 330 nm.

[0141] 2) Pretreatment of organic-inorganic hybrid fluorescent crystal materials.

[0142] Place 15g of the fluorescent material obtained in step 1) in a beaker, immerse the fluorescent material in an appropriate amount of ethanol, then add 0.3g of a mixture of titanate coupling agent and ethanol (mass ratio 1 / 3), and stir magnetically (300r / min) for 1h at room temperature to uniformly disperse the titanate coupling agent on the surface of the phosphor. Keep it under vacuum (-0.1MPa) at 120℃ for 2h, and after evaporating the ethanol, obtain the pretreated polycrystalline fluorescent material powder.

[0143] 3) Preparation of polylactic acid fluorescent anti-counterfeiting fiber.

[0144] First, a 15% (w / w) polylactic acid (PLA) fluorescent masterbatch was prepared using a twin-screw extruder. 100g of the PLA fluorescent masterbatch and 200g of pure PLA chips were dried at 120℃ for 24 hours. Next, melt spinning was performed to produce 5% (w / w) PLA fluorescent anti-counterfeiting fibers. The spinneret orifice diameter was 0.4mm, the spinning temperature was 210–230℃, and the winding rate was 600m / min. Finally, the nascent fibers were stretched using a parallel stretching machine at 50℃ for both the hot plate and the hot plate, with a stretching ratio of 3 times. The resulting PLA fluorescent anti-counterfeiting fibers were then obtained.

[0145] 4) Detection, analysis and characterization of the prepared polylactic acid fluorescent anti-counterfeiting fibers.

[0146] The morphology, fluorescence properties, and thermal stability of the prepared polylactic acid fluorescent anti-counterfeiting fibers were detected, analyzed, and characterized.

[0147] Morphological analysis of polylactic acid fluorescent anti-counterfeiting fibers was performed using scanning electron microscopy.

[0148] The thermal stability of polylactic acid fluorescent anti-counterfeiting fiber was analyzed using a thermogravimetric analyzer.

[0149] The fluorescence properties of polylactic acid fluorescent anti-counterfeiting fibers were analyzed using a fluorescence spectrometer.

[0150] The distribution of fluorescent particles in polylactic acid fluorescent anti-counterfeiting fibers was analyzed using laser confocal microscopy.

[0151] See Figure 3 , Figure 3 This is a scanning electron microscope image of the polylactic acid fluorescent anti-counterfeiting fiber prepared in Example 1 of the present invention.

[0152] Depend on Figure 3 It is known that polylactic acid fluorescent anti-counterfeiting fibers are randomly arranged, with uniform diameter distribution and smooth surface, and their diameter is approximately 0.7–1.2 μm.

[0153] See Figure 4 , Figure 4 The differential thermal curve of the polylactic acid fluorescent anti-counterfeiting fiber prepared in Example 1 of this invention is shown.

[0154] Depend on Figure 4 It is known that the thermal stability temperature of polylactic acid fluorescent anti-counterfeiting fiber can reach 167℃.

[0155] See Figure 5 , Figure 5 The fluorescence spectrum of the polylactic acid fluorescent anti-counterfeiting fiber prepared in Example 1 of this invention is shown.

[0156] Depend on Figure 5It can be seen that polylactic acid fluorescent anti-counterfeiting fiber has two main emission peaks located at 447nm and 542nm respectively, with the strongest emission wavelength located at 542nm.

[0157] See Figure 6 , Figure 6 This is a laser confocal fluorescence distribution map of the polylactic acid fluorescent anti-counterfeiting fiber prepared in Example 1 of the present invention.

[0158] Depend on Figure 6 It can be seen that the fluorescent particles are uniformly distributed in the polylactic acid fluorescent anti-counterfeiting fiber.

[0159] Example 2

[0160] 1) Prepare an organic-inorganic hybrid fluorescent material.

[0161] 11) Dissolve 0.02 mol of 2-hydroxypyridine and 0.04 mol of phosphoric acid in 40 mL of water;

[0162] 12) Place the beaker containing the mixed aqueous solution from step 11) on a magnetic stirrer and heat it to 100 degrees Celsius while stirring continuously until the solution is concentrated to 20 mL. Then cool and crystallize. Three days later, a large number of colorless and transparent single crystals appear, with a yield of more than 90%.

[0163] 13) Place the crystals obtained in step 12) in a desiccator to allow moisture to evaporate naturally. Perform XRD testing on the obtained crystals. The X-ray diffraction pattern of the product prepared by the method in this embodiment is consistent with... Figure 2 same.

[0164] 2) Pretreatment of organic-inorganic hybrid fluorescent crystal materials.

[0165] Place 30g of the fluorescent material obtained in step 1) in a beaker, immerse the fluorescent material in an appropriate amount of ethanol, and then add 0.6g of a mixture of titanate coupling agent and ethanol (mass ratio 1 / 3). Stir magnetically (300r / min) at room temperature for 1h to uniformly disperse the titanate coupling agent on the surface of the phosphor. Maintain the mixture under vacuum (-0.1MPa) at 120℃ for 2h. After evaporating the ethanol, the pretreated polycrystalline fluorescent material powder is obtained.

[0166] 3) Preparation of polylactic acid fluorescent anti-counterfeiting fiber.

[0167] First, a polylactic acid (PLA) fluorescent masterbatch with a mass fraction of 15% polycrystalline powder was prepared using a twin-screw extruder. 200g of the PLA fluorescent masterbatch and 100g of pure PLA chips were dried at 120℃ for 24 hours. Next, melt spinning was performed to prepare PLA fluorescent anti-counterfeiting fibers with a mass fraction of 10%. The spinneret orifice diameter was 0.4mm, the spinning temperature was 210–230℃, and the winding rate was 600m / min. Finally, the nascent fibers were stretched using a parallel stretching machine with a hot plate temperature of 50℃ and a stretching ratio of 3 times. The resulting PLA fluorescent anti-counterfeiting fibers were then obtained.

[0168] The foregoing has provided a detailed description of an organic-inorganic hybrid crystal material, its preparation method, and its applications, as well as a polylactic acid fluorescent anti-counterfeiting fiber based on a novel hybrid fluorescent material and its preparation method. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are merely for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the wording of the claims, or if they include equivalent structural elements that are not substantially different from the wording of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. An organic-inorganic hybrid crystal material, characterized in that, The chemical formula of the organic-inorganic hybrid crystal material is (C5H6NO). + (H2PO4) - ; The crystalline material belongs to the triclinic crystal system and has a space group of P-1. The organic group of the crystalline material is 2-hydroxypyridine; The crystal material is a fluorescent crystal material.

2. The organic-inorganic hybrid crystal material according to claim 1, characterized in that, The fluorescence is specifically a fluorescent crystal that emits green light; The unit cell parameters of the crystal material are: a = 6.9696(4) Å, b = 7.2675(5) Å, c = 9.2511(7) Å, α = 102.827(6) °, β = 100.129(5) °, γ = 112.781(6) °, Z = 2, and unit cell volume V = 402.99 Å. 3 .

3. The organic-inorganic hybrid crystal material according to claim 1, characterized in that, The anionic portion of the crystal material is dihydrogen phosphate ions; The crystalline material has a transmittance of greater than 70% in the 330~2600nm spectral range; The ultraviolet absorption cutoff wavelength of the crystal material is 330 nm. The crystal material includes crystal materials used in polylactic acid fluorescent anti-counterfeiting fibers.

4. A method for preparing an organic-inorganic hybrid crystal material as described in any one of claims 1 to 3, characterized in that, Includes the following steps: A mixture of 2-hydroxypyridine, a compound containing dihydrogen phosphate, and water was heated and then cooled to crystallize, yielding an organic-inorganic hybrid crystal material.

5. The preparation method according to claim 4, characterized in that, The compound containing dihydrogen phosphate is selected from one or more of phosphoric acid, lithium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, and rubidium dihydrogen phosphate. The molar ratio of the 2-hydroxypyridine to the compound containing dihydrogen phosphate is (0.01~1):(0.01~1). The molar volume ratio of 2-hydroxypyridine to water is (0.01~1) mol: (2~200) mL; The heating temperature is 40~100℃; The heating time is until the volume of the mixture is reduced to 45% to 95% of its initial volume.

6. The application of the organic-inorganic hybrid crystal material according to any one of claims 1 to 3 in polylactic acid fluorescent anti-counterfeiting fibers.

7. A polylactic acid fluorescent anti-counterfeiting fiber, characterized in that, The polylactic acid fluorescent anti-counterfeiting fiber contains fluorescent polycrystalline materials; The fluorescent polycrystalline material includes the organic-inorganic hybrid crystal material as described in any one of claims 1 to 3.

8. The polylactic acid fluorescent anti-counterfeiting fiber according to claim 7, characterized in that, The fluorescent material is a polycrystalline material based on an organic-inorganic hybrid crystal material; The fluorescent polycrystalline material includes an organic-inorganic hybrid crystal material and a titanate coupling agent composited on the surface of the organic-inorganic hybrid crystal material; The mass ratio of the titanate coupling agent to the organic-inorganic hybrid crystal material is (2~5):100; In the polylactic acid fluorescent anti-counterfeiting fiber, the mass content of the fluorescent polycrystalline material is 1%~10%.

9. A method for preparing polylactic acid fluorescent anti-counterfeiting fiber as described in any one of claims 7-8, characterized in that, Includes the following steps: 1) The organic-inorganic hybrid crystal material, titanate coupling agent and solvent are mixed, and after being allowed to stand under vacuum, the solvent is removed to obtain fluorescent polycrystalline material powder. 2) The fluorescent polycrystalline material powder obtained in the above steps is extruded with polylactic acid to obtain polylactic acid fluorescent masterbatch. Then, the polylactic acid fluorescent masterbatch and polylactic acid are melt-spun to obtain polylactic acid fluorescent anti-counterfeiting fiber.

10. The preparation method according to claim 9, characterized in that, The temperature for vacuum settling is 80~120℃; The vacuum settling time is 1-3 hours; The mass content of the polycrystalline fluorescent material in the polylactic acid fluorescent masterbatch is 5%~20%; The melt spinning temperature is 210~230℃.

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