A stereolithography long-life room temperature phosphorescent material and preparation and application thereof

Abstract

The present application belongs to the technical field of polymer and luminescent material, and more particularly relates to a kind of stereolithography long-life room temperature phosphorescence material and its preparation and application.Long-life room temperature phosphorescence material includes: polypropylene fumarate, hyperbranched polyester acrylate and phosphorescent molecule LAD;The number average molecular weight of polypropylene fumarate is 2800-4000 g / mol;With the total amount of polypropylene fumarate and hyperbranched polyester acrylate parts, the mass fraction of polypropylene fumarate is ≥58%;The mass fraction of phosphorescent molecule is 0.08-0.15%.The present application significantly improves the phosphorescent lifetime of LAD by matching LAD with polypropylene fumarate, hyperbranched polyester acrylate resin system.

Description

Technical Field

[0001] This invention belongs to the technical field of polymers and luminescent materials, and more specifically, relates to a stereolithographic long-life room-temperature phosphorescent material and its preparation and application. Background Technology

[0002] Organic room-temperature phosphorescent materials, with their advantages of long luminescence lifetime, large Stokes shift, tunable structure, and good flexibility, have shown great application potential in fields such as information encryption and anti-counterfeiting of high-end products. Compared with traditional inorganic phosphorescent materials, they are easier to composite with polymer matrices to achieve functionalization. However, the phosphorescence performance of most organic room-temperature phosphorescent materials is easily affected by molecular aggregation and oxygen quenching, requiring a polymer matrix for performance enhancement. How to combine phosphorescent small molecules with a formable polymer matrix to achieve integrated preparation of phosphorescence function and fine structure has become a key challenge for their application in the anti-counterfeiting field.

[0003] 3D printing technology can precisely construct objects of arbitrarily complex geometries based on digital models. Among them, surface projection micro-stereolithography, as a micron-level high-precision photopolymerization 3D printing method, can achieve high-fidelity manufacturing of complex and delicate structures, providing design freedom for the application of functional materials in the field of anti-counterfeiting. Combining organic room-temperature phosphorescent materials with high-precision 3D printing technology holds promise for the direct manufacturing of anti-counterfeiting devices that integrate structure and phosphorescence functionality. Selecting a suitable polymer matrix is ​​the core to achieving this goal.

[0004] The paper "Time-Dependent Multicolor Afterglow from Dual Persistent Luminescence of Fluorescence and Phosphorescence in a UV-Cured PolyurethaneMatrix (Siyang Jiang, Danman Guo, ACS Materials Lett, https: / / doi.org / 10.1021 / acsmaterialslett.3c01498)" discloses a time-dependent multicolor afterglow polyurethane system. This system, obtained through rapid UV-curing copolymerization of a pyrene-1-carboxylic acid ester derivative (PyC) and poly-ε-caprolactone (PCL) prepolymer, exhibits a phosphorescence lifetime of 217 ms at 626 nm. With its multicolor afterglow variation characteristics and rapid UV-curing preparation process, this material shows broad application prospects in the field of time-dependent three-level information encryption and anti-counterfeiting. However, the phosphorescence lifetime of the polymer system provided by the above method still suffers from a relatively short phosphorescence lifetime. How to further improve the phosphorescence lifetime of phosphorescent molecule-based polymer systems and apply them to the field of 3D printing has become a pressing technical problem to be solved in this field. Summary of the Invention

[0005] In view of the aforementioned problems in the prior art, the primary objective of this invention is to provide a long-life room-temperature phosphorescent material.

[0006] The second objective of this invention is to provide a method for preparing a long-life room-temperature phosphorescent material.

[0007] The third objective of this invention is to provide a long-life room-temperature phosphorescent thin film.

[0008] The fourth objective of this invention is to provide a 3D printed part.

[0009] The fifth objective of this invention is to provide an application of a long-life room-temperature phosphorescent material, a long-life room-temperature phosphorescent film, or a 3D printed part in the field of information encryption and anti-counterfeiting.

[0010] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0011] This invention seeks to protect a long-life room-temperature phosphorescent material, comprising: polypropylene fumarate, hyperbranched polyester acrylate, and phosphorescent molecules;

[0012] The structural formula of the phosphorescent molecule is:

[0013] ;

[0014] The number-average molecular weight of the poly(propylene fumarate) is 2800-4000 g / mol.

[0015] Based on the total amount of polypropylene fumarate and hyperbranched polyester acrylate, the mass percentage of polypropylene fumarate is ≥58%;

[0016] The total mass percentage of phosphorescent molecules is 0.08-0.15% based on the total amount of polyfuric acid propylene glycol ester and hyperbranched polyester acrylate.

[0017] In this invention, phosphorescent molecule (LAD) is a pyrene ring-based small organic molecule with excellent room temperature phosphorescence emission characteristics. Its conjugated structure is conducive to the occurrence of intersystem crossing process and is an ideal phosphorescent functional unit. However, when used alone, its phosphorescence performance is easily degraded and needs to be stabilized by a polymer matrix.

[0018] This invention, through research, discovered that persistent free radicals exist in the photocrosslinking network formed by poly(propylene fumarate) ester. These free radicals can drive continuous crosslinking of the network and construct a dynamically enhanced rigid microenvironment, effectively suppressing non-radiative transitions and oxygen quenching of phosphorescent small molecules, thus significantly improving the phosphorescence performance of phosphorescent molecules. The inventors combined LAD with a system of poly(propylene fumarate) ester and hyperbranched polyester acrylate resin, utilizing the photocrosslinking properties and persistent free radical effect of poly(propylene fumarate) ester to enhance the phosphorescence performance of LAD. This effectively suppressed non-radiative transitions of LAD triplet excitons and blocked the penetration and quenching of oxygen molecules. Furthermore, the hydrogen bonding between the hydroxyl groups of the hyperbranched polyester acrylate resin and the poly(propylene fumarate) ester backbone further ensured the stability of phosphorescence performance, solving the technical problems of easy aggregation and oxygen quenching of phosphorescent small molecules.

[0019] The present invention improves the phosphorescence lifetime of LAD to 405 ms through the above system, which is much higher than the microsecond level of the traditional diethyl fumarate system; it is also significantly better than the phosphorescence lifetime of existing polyurethane systems containing LAD.

[0020] The long-life room temperature phosphorescent material provided by this invention, combined with high-precision 3D printing technology, can achieve integrated molding of phosphorescent function and fine structure, and realize the composite molding of organic phosphorescent small molecule LAD and polyfuric acid propylene glycol ester-based resin and high-precision 3D printing molding.

[0021] Specifically, the number-average molecular weight of the polypropylene fumarate can be 2800 g / mol, 3000 g / mol, 3200 g / mol, 3400 g / mol, 3500 g / mol, 3600 g / mol, 3800 g / mol, etc., or any range formed by the above values, such as 2800-3800 g / mol, 2800-3500 g / mol, 2800-3000 g / mol, 3000-3200 g / mol, 3000-3500 g / mol, etc., and the present invention is not limited thereto.

[0022] Specifically, based on the total amount of polypropylene glycol ester and hyperbranched polyester acrylate, the mass percentage of polypropylene glycol ester can be 60%, 62%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, etc., or any range formed by the above values, such as 60-70%, 60-80%, 60-90%, 80-100%, etc., and the present invention is not limited thereto. Specifically, based on the total amount of polypropylene glycol ester and hyperbranched polyester acrylate, the mass percentage of phosphorescent molecules can be 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, etc., or any range formed by the above values, such as 0.09-0.11%, 0.08-0.12%, 0.1-0.12%, 0.1-0.13%, etc., and the present invention is not limited thereto.

[0023] Preferably, the long-lifetime room-temperature phosphorescent material comprises, by weight parts: 60-100 parts of polypropylene fumarate, 0.1-40 parts of hyperbranched polyester acrylate, and 0.05-0.5 parts of phosphorescent molecules. More preferably, the long-lifetime room-temperature phosphorescent material comprises, by weight parts: 60-65 parts of polypropylene fumarate, 35-40 parts of hyperbranched polyester acrylate, and 0.08-0.12 parts of phosphorescent molecules. Under these preferred conditions, the prepared long-lifetime room-temperature phosphorescent material has a longer phosphorescence lifetime.

[0024] Specifically, the weight parts of polypropylene fumarate can be 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, etc., or any range formed by the above values, such as 60-70 parts, 60-80 parts, 60-90 parts, 80-100 parts, etc., and the present invention is not limited thereto. Specifically, the weight parts of hyperbranched polyester acrylate can be 1 part, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, etc., or any range formed by the above values, such as 1-40 parts, 35-40 parts, 30-40 parts, 35-45 parts, 40-50 parts, etc., and the present invention is not limited thereto. Specifically, the weight parts of the phosphorescent molecules can be 0.08 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, etc., or any range formed by the above values, such as 0.08-0.15 parts, 0.1-0.2 parts, 0.1-0.3 parts, 0.1-0.4 parts, etc., but the present invention is not limited thereto.

[0025] Preferably, the number-average molecular weight of the polypropylene fumarate is 3000-3500 g / mol; more preferably, the number-average molecular weight of the polypropylene fumarate is 3000-3200 g / mol. Under these preferred conditions, the prepared long-lifetime room-temperature phosphorescent material has a longer phosphorescence lifetime.

[0026] Preferably, the mass percentage of phosphorescent molecules is 0.1-0.12% based on the total amount of polypropylene fumarate and hyperbranched polyester acrylate. Under these preferred conditions, the prepared long-life room temperature phosphorescent material has a longer phosphorescence lifetime.

[0027] Preferably, the long-life room-temperature phosphorescent material further includes 0.1-3 parts of a photoinitiator.

[0028] Preferably, the photoinitiator is selected from at least one of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, photoinitiator 784, or photoinitiator 754. More preferably, the photoinitiator is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide. Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide has good light absorption characteristics in the wavelength range of 365-405 nm.

[0029] Preferably, the long-life room temperature phosphorescent material further includes 0.05-0.5 parts of a light-blocking agent.

[0030] Preferably, the opacifier is selected from at least one of Orange G, lemon yellow dye, curcumin, and red watercolor dye. More preferably, the opacifier is Orange G; it has characteristic absorption at a wavelength of 405 nm, which is used to control the curing depth.

[0031] Preferably, the preparation method of the polypropylene fumarate includes the following steps: under a nitrogen atmosphere, fumarate, 1,2-propanediol, catalyst and polymerization inhibitor are mixed and polymerized to obtain bis(hydroxypropyl)fumarate diester; then further reaction is carried out to obtain the polypropylene fumarate.

[0032] Preferably, the polymerization reaction includes two steps, specifically: (1) the mixture is polymerized at 90-110°C for 0.5-1.5h; (2) the temperature is raised to 140-160°C and polymerized for 6.5-7h.

[0033] Preferably, the further reaction includes reacting bis(hydroxypropyl)fumarate diester at 140-160°C for 6.5-7.5 h under vacuum conditions.

[0034] Preferably, the polymerization reaction is followed by a purification step; the purification step includes: dissolving the polyfuric acid propylene glycol ester polymer in a solvent, washing it sequentially with hydrochloric acid solution, distilled water and saturated brine, drying the organic phase and filtering it, removing dichloromethane by rotary evaporation of the filtrate, adding it dropwise to excess petroleum ether to precipitate it, and drying it under vacuum to obtain purified polyfuric acid propylene glycol ester.

[0035] Preferably, the solvent includes, but is not limited to, dichloromethane.

[0036] Furthermore, this invention claims protection for a method for preparing a long-life room-temperature phosphorescent material, which involves uniformly mixing polypropylene fumarate, hyperbranched polyester acrylate, phosphorescent molecules, and other components contained in the system to obtain the long-life room-temperature phosphorescent material.

[0037] The long-life room-temperature phosphorescent material provided by this invention has a simple preparation process and is suitable for large-scale applications. The components are compounded through physical doping, resulting in a simple and mild preparation process that does not require complex chemical grafting modification, making it suitable for large-scale industrial production and various anti-counterfeiting application scenarios.

[0038] Preferably, the mixing temperature is 50-50°C. Preferably, the mixing time is 6-12 hours.

[0039] Furthermore, this invention claims protection for a long-life room temperature phosphorescent film, which is prepared by ultraviolet curing using the aforementioned long-life room temperature phosphorescent material.

[0040] Preferably, in some more specific embodiments, a long-life room temperature phosphorescent film is prepared by injecting the aforementioned long-life room temperature phosphorescent material into a mold and irradiating it under an ultraviolet lamp for curing.

[0041] Preferably, the wavelength of the ultraviolet light is 365-405 nm, and the intensity of the ultraviolet light is 4000-5000 mW / cm². 2 .

[0042] Preferably, the thickness of the long-life room-temperature phosphorescent film is 0.05-0.5 mm. Specifically, the thickness of the long-life room-temperature phosphorescent film can be 0.08 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, etc., or any range formed by the above values, such as 0.08-0.12 mm, 0.08-0.15 mm, 0.1-0.15 mm, 0.1-0.2 mm, 0.1-0.25 mm, 0.1-0.5 mm, 0.25-0.5 mm, etc., and the present invention is not limited thereto.

[0043] More preferably, the thickness of the long-life room-temperature phosphorescent film is 0.1-0.15 mm. At this preferred thickness, the prepared long-life room-temperature phosphorescent material has a longer phosphorescence lifetime.

[0044] Preferably, the UV curing time is ≥30 min. More preferably, the UV curing time is 30-60 min. More preferably, the UV curing time is 50-60 min. Under these preferred curing times, the prepared long-life room temperature phosphorescent material has a longer phosphorescence lifetime.

[0045] Furthermore, this invention claims protection for a 3D printed part, which is prepared by 3D printing using a first photocurable resin and a second photocurable resin.

[0046] The first photocurable resin is the aforementioned long-life room temperature phosphorescent material;

[0047] The phosphorescence lifetime of the first photocurable resin is 350-450 ms; the phosphorescence lifetime of the second photocurable resin is 210-310 μs.

[0048] Preferably, the second photocurable resin comprises, by weight parts: polypropylene fumarate, diethyl fumarate, and phosphorescent molecules;

[0049] The structural formula of the phosphorescent molecule is:

[0050] ;

[0051] The number-average molecular weight of the poly(propylene fumarate) is 2800-4000 g / mol.

[0052] Based on the total amount of polypropylene fumarate and diethyl fumarate, the mass percentage of polypropylene fumarate is ≥60%;

[0053] Based on the total amount of polypropylene fumarate and diethyl fumarate, the mass percentage of phosphorescent molecules is 0.08-0.15%.

[0054] Preferably, the second photocurable resin comprises, by weight, 60-100 parts of polypropylene fumarate, 0.1-40 parts of diethyl fumarate, and 0.05-0.5 parts of phosphorescent molecules. More preferably, the second photocurable resin comprises, by weight, 60-65 parts of polypropylene fumarate, 35-40 parts of diethyl fumarate, and 0.08-0.12 parts of phosphorescent molecules.

[0055] This invention utilizes the differences in phosphorescence lifetime of resins with different formulations to construct a time-dependent multi-level anti-counterfeiting code, significantly improving the confidentiality and anti-counterfeiting level of information encryption. This invention allows resins with different phosphorescence lifetimes to be printed in different areas of the same structure to construct a time-dependent multi-level anti-counterfeiting code, achieving a dynamic encryption effect where different coded information is presented at different time points after ultraviolet light excitation.

[0056] The 3D printed part provided by this invention, after being excited under ultraviolet light for 10 seconds and then having its light source turned off, utilizes the difference in the decay time of phosphorescence in different areas of the resin to present different encoded information at different time points. Specifically, after ultraviolet light excitation, it exhibits blue fluorescence; when the ultraviolet light is turned off for 0.2 seconds, all areas display pink phosphorescence, presenting the initial complete encoded information; after the ultraviolet light is turned off for 0.6 seconds, the phosphorescence in the second photocurable resin area completely decays, while the phosphorescence in the first photocurable resin area remains clearly visible, presenting secondary encrypted encoded information, thus achieving dynamic, multi-level information encryption and anti-counterfeiting.

[0057] This invention pioneers a dynamic information encoding method based on the differences in lifespan of different phosphorescent resins, filling a gap in the application of phosphorescent small molecule-resin composite 3D printing technology in the field of information encryption and anti-counterfeiting. The composite of phosphorescent small molecules and resin systems provided by this invention achieves integrated fabrication of phosphorescent functionality and 3D printed structures, eliminating the need for subsequent functional modification, simplifying the fabrication process of anti-counterfeiting devices, and meeting the dual requirements of high-end anti-counterfeiting fields for fine structures and functionalization.

[0058] Furthermore, this invention seeks protection for the application of a long-life room-temperature phosphorescent material, a long-life room-temperature phosphorescent film, or a 3D printed part in the field of information encryption and anti-counterfeiting.

[0059] Preferably, the 3D printing includes the following steps: injecting a first photocurable resin and a second photocurable resin into a 3D printer respectively; performing layer-by-layer photocurable printing according to the designed three-dimensional model to obtain a three-dimensional structural part with room temperature phosphorescence properties; and placing the three-dimensional structural part under ultraviolet light for post-curing treatment after printing.

[0060] Preferably, the parameters for the photopolymerization printing are: exposure energy 10-20 mJ / cm². 2 The layer thickness is 20 μm.

[0061] Preferably, the wavelength of the ultraviolet light is 365-405 nm, and the intensity of the ultraviolet light is 10-20 mW / cm². 2 Each layer takes 2-3 seconds to print.

[0062] Preferably, the post-curing time is 20-30 minutes.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] This invention combines LAD with a system of polypropylene fumarate and hyperbranched polyester acrylate resin. By utilizing the photocrosslinking properties and persistent free radical effect of polypropylene fumarate, the phosphorescence performance of LAD is enhanced. This effectively suppresses the nonradiative transition of LAD triplet excitons and blocks the penetration and quenching of oxygen molecules. The invention significantly improves the phosphorescence lifetime of LAD through the above system. Attached Figure Description

[0065] Figure 1 Infrared spectrum of HPPF / HPA-LAD room temperature phosphorescent resin.

[0066] Figure 2 The normalized ultraviolet absorption spectra of the HPPF / HPA-LAD room temperature phosphorescent resin film prepared in Example 1 and the HPPF / DEF-LAD room temperature phosphorescent resin film prepared in Comparative Example 1 are shown below; Figure 2 In the figure, 'a' represents the normalized ultraviolet absorption spectrum of the HPPF / DEF-LAD room temperature phosphorescent resin film prepared in Comparative Example 1. Figure 2 In this context, b represents the normalized ultraviolet absorption spectrum of the HPPF / HPA-LAD room temperature phosphorescent resin film prepared in Example 1.

[0067] Figure 3 Comparison of fluorescence spectra of HPPF / HPA-LAD room temperature phosphorescent resin film and HPPF / DEF-LAD room temperature phosphorescent resin film.

[0068] Figure 4 Phosphorescence spectra of room temperature phosphorescent resins prepared with different amounts of LAD doping of phosphorescent molecules.

[0069] Figure 5 Phosphorescence spectra of room temperature phosphorescent resins prepared with different HPPF contents.

[0070] Figure 6 Phosphorescence spectra of thin film samples with different HPPF contents after vacuum treatment.

[0071] Figure 7 Phosphorescence spectra of thin film samples of different thicknesses.

[0072] Figure 8 Phosphorescence spectra of thin film samples prepared for different UV curing times.

[0073] Figure 9 The phosphorescence spectra of the thin film samples prepared in Example 1, Comparative Example 12, and Comparative Example 1 after being placed at room temperature for 1 day, 7 days, 14 days, 21 days, and 42 days are shown. Figure 9 In this context, 'a' refers to the thin film sample prepared in Example 1; Figure 9 In the figure, b represents the thin film sample prepared in Comparative Example 12; Figure 9 c in the figure represents the thin film sample prepared in Comparative Example 1.

[0074] Figure 10 This is a schematic diagram showing the phosphorescence lifetime of the thin film samples prepared in Example 1, Comparative Example 1, Comparative Example 12, and Comparative Example 13; wherein, Figure 10 In the figure, 'a' represents a schematic diagram of the phosphorescence lifetime of the LPPF / DEF-LAD thin film sample. Figure 10 In the figure, b is a schematic diagram of the phosphorescence lifetime of the HPPF / DEF-LAD thin film sample; Figure 10 In the figure, c represents the phosphorescence lifetime of the LPPF / HPA-LAD thin film sample. Figure 10 In the figure, d represents the phosphorescence lifetime of the HPPF / HPA-LAD thin film sample.

[0075] Figure 11 This is a comparison chart of the printing accuracy of HPPF / HPA-LAD resin in Example 1; where, Figure 11 In the figure, 'a' is a schematic diagram showing the relationship between the exposure energy and the printing diameter of HPPF / HPA-LAD resin and HPPF / HPA. Figure 11 In the diagram, b represents the relationship between exposure energy and printing resolution for HPPF / HPA-LAD resin and HPPF / HPA. Figure 11 In the diagram, 'c' represents the relationship between the exposure energy and the curing depth of HPPF / HPA. Figure 11 In the diagram, d represents the relationship between the printing light intensity and printing speed of HPPF / HPA-LAD resin and HPPF / HPA.

[0076] Figure 12 These are photographs of a 2D graphic 3D printed using HPPF / HPA-LAD resin under sunlight, ultraviolet light, and after ultraviolet light was turned off.

[0077] Figure 13 These are phosphorescently encoded photographs of a digital tube structure printed using a mixture of HPPF / HPA-LAD and HPPF / DEF resins at different time points.

[0078] Figure 14 The images show SEM images of the 3D structures 3D printed using HPPF / HPA-LAD resin and photographs of the printed structures under sunlight and with UV light switched on and off; among them, Figure 14 In the image, 'a' represents a SEM image of a three-dimensional structure 3D printed using HPPF / HPA-LAD resin. Figure 14 In the image, b is a photograph of the printed structure of HPPF / HPA-LAD resin under sunlight and ultraviolet light. Detailed Implementation

[0079] The present invention will be further described below with reference to the specification and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0080] Example 1

[0081] 1. Synthesis of polypropylene fumarate (PPF)

[0082] PPF is synthesized using a two-step transesterification reaction. The specific steps are as follows:

[0083] (1) Under nitrogen protection at room temperature, 50 g of diethyl fumarate was mixed with an excess (157.5 g) of 1,2-propanediol, and 0.15 g of hydroquinone as a polymerization inhibitor and 0.78 g of anhydrous zinc chloride as a catalyst were added. The mixture was polymerized at 300 rpm for 1 hour under vacuum (<0 MPa) and 100 °C, and then the temperature was slowly increased to 150 °C and the reaction continued for 7 hours before being cooled to 100 °C to obtain the intermediate product bis(hydroxypropyl) fumarate.

[0084] (2) The intermediate product bis(hydroxypropyl) fumarate diester from step (1) was reacted at 150 °C under vacuum (<0 MPa) for 7 hours to prepare an HPPF polymer with a number average molecular weight of 3000 g / mol.

[0085] (3) Purification: 87 g of HPPF polymer was dissolved in 500 mL of dichloromethane and washed twice with 2 L of 10 wt% hydrochloric acid solution to remove residual catalyst. The solution was then washed with 2 L of distilled water and 2 L of saturated brine. The organic phase was dried over anhydrous sodium sulfate and filtered. The filtrate was rotary evaporated at 40 °C to remove dichloromethane. The precipitate was then added dropwise to an excess of (1 L) petroleum ether and dried under vacuum at room temperature to obtain a pale yellow, viscous, molten purified HPPF polymer.

[0086] 2. Resin preparation

[0087] Under light-protected conditions, the above-mentioned HPPF polymer was dissolved in dichloromethane, which served as a co-solvent. After the HPPF polymer was fully dissolved, hyperbranched polyester acrylate (HPA, LeZn-UV8610, WBV Chemicals (Guangzhou, China)) was added, along with the phosphorescent molecule LAD and the photoinitiator phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO) (by weight, 60 parts HPPF polymer, 40 parts hyperbranched polyester acrylate, 0.1 parts phosphorescent molecule, 1 part photoinitiator, and 12 parts dichloromethane; wherein, the phosphorescent molecule LAD accounts for 0.1% of the total resin mass). The mixture was placed in a constant temperature shaker at 40 °C and shaken overnight to ensure thorough mixing of all components. The mixture was then placed in a vacuum oven at room temperature and evacuated for 12 hours (vacuum degree <0 MPa) to completely remove the co-solvent dichloromethane, thus preparing the HPPF / HPA-LAD room temperature phosphorescent resin. The infrared spectrum of the HPPF / HPA-LAD room temperature phosphorescent resin is shown below. Figure 1 As shown.

[0088] The structural formula of the phosphorescent molecule LAD is shown below:

[0089]

[0090] 3. Thin film sample preparation

[0091] The prepared HPPF / HPA-LAD room temperature phosphorescent resin was injected into a silicone mold with a thickness of 0.1 mm. The mold was clamped on both sides with a high-transmittance glass plate and placed under a 365 nm ultraviolet lamp (wavelength 365 nm) for 30 minutes to obtain a cured film sample.

[0092] Example 2-3

[0093] The difference between Examples 2-3 and Example 1 is as follows: In step 2, the amount of phosphorescent molecule LAD and photoinitiator remains unchanged, and the total amount of hyperbranched polyester acrylate and HPPF polymer (100 parts) remains unchanged. The amount of HPPF polymer is 80 parts and 100 parts, respectively, and the corresponding amount of hyperbranched polyester acrylate is 20 parts and 0 parts.

[0094] Examples 4-6

[0095] The difference between Examples 4-6 and Example 1 is that the thickness of the samples obtained in step 3 is 0.25 mm and 0.5 mm, respectively.

[0096] Example 7

[0097] The difference between Example 7 and Example 1 is that in step 3, the sample is placed under a 365 nm ultraviolet lamp (wavelength 365 nm) for 60 minutes.

[0098] Comparative Example 1

[0099] The difference between Comparative Example 1 and Example 1 is that in step 2, diethyl fumarate (DEF) was used instead of hyperbranched polyester acrylate (HPA). HPPF / DEF-LAD room temperature phosphorescent resin and film samples based on HPPF / DEF-LAD room temperature phosphorescent resin were prepared.

[0100] Comparative Examples 2-4

[0101] The difference between Comparative Examples 2-4 and Example 1 is that, in step 2, the total amount of HPPF polymer and hyperbranched polyester acrylate is kept constant, and 0.05%, 0.5%, and 1% of phosphorescent molecules LAD are added according to the total mass of the resin.

[0102] Comparative Examples 5-6

[0103] The difference between Comparative Examples 5-6 and Example 1 is that in step 2, the amount of phosphorescent molecule LAD and photoinitiator remains unchanged, and the total amount of hyperbranched polyester acrylate and HPPF polymer remains unchanged. The amount of HPPF polymer is 40 parts and 50 parts, respectively, and the corresponding amount of hyperbranched polyester acrylate is 60 parts and 50 parts.

[0104] Comparative Examples 7-8

[0105] The difference between Comparative Examples 7-8 and Example 1 is that, in step 3, the thickness of the samples obtained is 0.75 mm and 1 mm, respectively.

[0106] Comparative Examples 9-11

[0107] The difference between Comparative Examples 9-11 and Example 1 is that in step 3, the samples were placed under a 365 nm ultraviolet lamp (wavelength 365 nm) for 5 minutes, 10 minutes, and 15 minutes, respectively.

[0108] Comparative Example 12

[0109] The difference between Comparative Example 12 and Example 1 is that in step (2) of the synthesis of polypropylene fumarate (PPF), the intermediate product bis(hydroxypropyl) fumarate diester of step (1) was placed under vacuum at 150 °C for 4 hours to prepare an LPPF polymer with a number average molecular weight of 1500 g / mol (LPPF) and a thin film sample based on LPPF / HPA-LAD room temperature phosphorescent resin.

[0110] Comparative Example 13

[0111] The difference between Comparative Example 13 and Example 1 is as follows: In step (2) of the synthesis of polypropylene fumarate (PPF), the intermediate product bis(hydroxypropyl) fumarate diester of step (1) was reacted under vacuum at 150 °C for 4 hours to prepare an LPPF polymer with a number average molecular weight of 1500 g / mol (LPPF); in step 2, diethyl fumarate was used to replace hyperbranched polyester acrylate, and finally a thin film sample of LPPF / DEF-LAD room temperature phosphorescent resin was prepared.

[0112] Test Example 1

[0113] The normalized ultraviolet absorption spectra of the HPPF / HPA-LAD room-temperature phosphorescent resin film prepared in Example 1 and the HPPF / DEF-LAD room-temperature phosphorescent resin film prepared in Comparative Example 1 were measured using a UV-Vis spectrophotometer (Shimadzu UV-2600, Japan). Specifically, the samples were cut into 13 mm diameter discs and fixed on a sample holder. The transmission mode of the UV-Vis spectrophotometer was used, with air as a reference, to measure the transmission spectra of the samples in the wavelength range of 300-700 nm.

[0114] Figure 2 Normalized ultraviolet absorption spectra of the HPPF / HPA-LAD room temperature phosphorescent resin film prepared in Example 1 and the HPPF / DEF-LAD room temperature phosphorescent resin film prepared in Comparative Example 1.

[0115] like Figure 2 As shown, both samples exhibit a strong absorption peak at approximately 310 nm, corresponding to the characteristic absorption band of BAPO photoinitiator, indicating good photoresponse capability in the ultraviolet region. The absorption peak of HPPF / DEF-LAD is relatively sharp, reaching its maximum normalized absorbance at 310 nm, and then rapidly decaying with increasing wavelength. In contrast, the absorption peak of HPPF / HPA is relatively broader, maintaining high absorbance in the 300-325 nm range, and exhibiting a distinct secondary absorption shoulder at 350-400 nm, indicating that its absorption capability for longer wavelength ultraviolet light is superior to that of HPPF / DEF.

[0116] The fluorescence spectra of the HPPF / HPA-LAD room temperature phosphorescent resin film prepared in Example 1 and the HPPF / DEF-LAD room temperature phosphorescent resin film prepared in Comparative Example 1 were tested using a delayed phosphorescence spectrometer (Guangxi Pusisen Optoelectronic Technology Co., Ltd., Ocean Optics QE65Prosystem). The phosphorescence and fluorescence time decay intensity curves were measured using a spectrophotometer with an excitation wavelength of 365 nm and a light intensity of 100%.

[0117] Figure 3A comparison of the fluorescence spectra of HPPF / HPA-LAD room temperature phosphorescent resin films and HPPF / DEF-LAD room temperature phosphorescent resin films. Figure 3 It is evident that, at the same HPPF content, the fluorescence emission peak intensity of HPPF / HPA is significantly higher than that of HPPF / DEF, with its main peak intensity reaching approximately 70,000, while that of HPPF / DEF is only approximately 50,000. Fluorescence intensity is closely related to the degree of intramolecular conjugation and the rigidity of the microenvironment. With increasing HPPF content, the density of the cross-linked network increases, restricting intramolecular rotation and non-radiative transitions, thereby leading to enhanced fluorescence intensity.

[0118] Test Example 2

[0119] (1) Fluorescence spectrometer (Guangxi Pusisen Optoelectronic Technology Co., Ltd., Ocean Optics QE65Prosystem) was used for testing. The excitation wavelength was 365 nm and the light intensity was 100%. The fluorescence and phosphorescence spectra of different room temperature phosphorescent resins were tested.

[0120] Figure 4 Phosphorescence spectra of thin film samples prepared with different LAD doping levels of phosphorescent molecules. Figure 4 As shown, the phosphorescence intensity reaches its peak when the LAD doping concentration is 0.1%. When the LAD doping concentration exceeds 0.1%, the phosphorescence intensity exhibits a significant decreasing trend, confirming the concentration quenching effect of the phosphorescent dopant. At low concentrations, LAD molecules are uniformly dispersed, and triplet excitons can effectively generate phosphorescence through radiative transitions. When the doping concentration is too high, LAD molecules aggregate, intermolecular interactions are enhanced, leading to a significant increase in the probability of non-radiative transitions and a significant decrease in phosphorescence intensity.

[0121] Figure 5 Phosphorescence spectra of thin film samples prepared with different HPPF contents. Figure 5 It can be seen that the phosphorescence intensity gradually increases with the increase of HPPF content. When the HPPF content reaches 60%, the intensity increase tends to level off and remains basically stable, which confirms the regulatory effect of cross-linking network densification on phosphorescence performance. When the HPPF content is below 60%, the proportion of HPA diluent is too high, the cross-linking network is loose, and oxygen molecules can easily penetrate and quench triplet excitons. When the HPPF content reaches 60% or above, the densification degree of the cross-linking network reaches a critical value, forming an effective physical barrier layer that restricts the penetration and diffusion of oxygen molecules.

[0122] Thin film samples with different HPPF contents were placed in a vacuum oven and kept at a vacuum level of <0 MPa for 12 h. Figure 6 Phosphorescence spectra of thin film samples with different HPPF contents after vacuum treatment. Figure 6It can be seen that after vacuuming, the phosphorescence intensity increased and the intensity difference between samples with different HPPF contents decreased, which directly verified the dominant role of oxygen molecule quenching and the mechanism of cross-linked network densification as the core factor of oxygen barrier.

[0123] Figure 7 Phosphorescence spectra of thin film samples of different thicknesses. Figure 7 It can be seen that the phosphorescence intensity increases significantly with the decrease of the film sample thickness. When the thickness decreases from 1 mm to 0.1 mm, the phosphorescence intensity increases by about 2 times.

[0124] Figure 8 Phosphorescence spectra of thin film samples prepared for different UV curing times. Figure 8 It can be seen that the phosphorescence intensity gradually increases with the extension of curing time. After the curing time reaches 30 min, the intensity growth tends to slow down and enters a stable plateau period.

[0125] Figure 9 The phosphorescence spectra of the thin film samples prepared in Example 1, Comparative Example 1, and Comparative Example 12 after being placed at room temperature for 1 day, 7 days, 14 days, 21 days, and 42 days are shown. Figure 9 In this context, 'a' refers to the thin film sample prepared in Example 1; Figure 9 In the figure, b represents the thin film sample prepared in Comparative Example 12; Figure 9 In the figure, c represents the thin film sample prepared in Comparative Example 1. (The text appears to be incomplete and contains several Figure 9 It can be seen that the phosphorescence intensity shows a continuous upward trend with the extension of the storage time, and finally tends to stabilize at about 21 days. This pattern is highly consistent with the decay period of persistent free radicals in the HPPF crosslinking network, confirming the enhancing effect of the post-curing process influenced by free radicals on phosphorescence performance.

[0126] Figure 10 This is a schematic diagram showing the phosphorescence lifetime of the thin film samples prepared in Example 1, Comparative Example 1, Comparative Example 12, and Comparative Example 13. The phosphorescence time decay curves were measured using a spectrophotometer (Horiba JY FL-3), with an excitation wavelength of 333 nm and a light intensity of 100%. Figure 10It was found that the phosphorescence lifetime of the HPPF / HPA-LAD system reached 405 ms, far exceeding the 260 μs of the HPPF / DEF system; furthermore, it was significantly higher than the 184 ms phosphorescence lifetime of the LPPF / HPA-LAD system, confirming that the hydrogen bonding between the hydroxyl groups in the HPA diluent and the PPF backbone effectively enhanced network rigidity and suppressed non-radiative transitions; moreover, the phosphorescence lifetime of HPPF / HPA-LAD was significantly higher than that of LPPF / HPA-LAD. This is attributed to the higher molecular weight of HPPF forming a denser cross-linked network, effectively limiting the penetration of oxygen molecules, while providing a more stable microenvironment for residual free radicals, making the post-curing process more durable and continuously enhancing network rigidity.

[0127] Test Example 3: 3D Printing Applications of HPPF / HPA-LAD Resin

[0128] 1. Resin preparation

[0129] HPPF / HPA-LAD resin was prepared according to the method in Example 1.

[0130] 2. Printing parameter optimization

[0131] A surface projection micro-stereolithography 3D printer (Mofang Precision, nanoArch P140) was used, with the printing wavelength set at 405 nm, layer thickness at 20 μm, and exposure energy at 10-20 mJ / cm². 2 Each layer takes 2-4 seconds to print. Printing accuracy is assessed by printing patterns at different resolutions, and the relationship between printing speed and accuracy is evaluated by printing structures with different line widths.

[0132] Figure 11 This is a comparison chart of the printing accuracy of HPPF / HPA-LAD resin in Example 1; where, Figure 11 In the figure, 'a' is a schematic diagram showing the relationship between the exposure energy and the printing diameter of HPPF / HPA-LAD resin and HPPF / HPA. Figure 11 In the diagram, b represents the relationship between exposure energy and printing resolution for HPPF / HPA-LAD resin and HPPF / HPA. Figure 11 In the diagram, 'c' represents the relationship between the exposure energy and the curing depth of HPPF / HPA. Figure 11 In the diagram, d represents the relationship between the printing light intensity and printing speed of HPPF / HPA-LAD resin and HPPF / HPA.

[0133] The preparation of HPPF / HPA follows the preparation method in Example 1, except that in step 2, no phosphorescent molecule LAD is added, and HPPF / HPA is finally obtained in step 2.

[0134] like Figure 11As shown, the critical exposure energy Ec of HPPF / HPA-LAD resin is 11.8 mJ / cm². 2 The curing depth Dp = 119.3 μm. Compared with HPPF / HPA resin without LAD, the printing accuracy was slightly improved and the curing depth was slightly reduced after LAD doping. This is a result of the increased light absorption caused by the light yellow color of LAD itself.

[0135] 3. Two-dimensional graphic printing

[0136] Optimized printing parameters were used (printing wavelength 405 nm, printing light intensity 20 mW / cm²). 2 Each layer was printed in 3 seconds, and two-dimensional graphics of the hollowed-out window lattice horse and the Sun Yat-sen University emblem were printed.

[0137] Figure 12 These are photographs of a 2D graphic 3D printed using HPPF / HPA-LAD resin under sunlight, ultraviolet light, and with ultraviolet light off. Figure 12 It can be seen that when the ultraviolet light is turned on, all printed graphics exhibit a bright blue fluorescence, with clear edges and complete details; 0.2 seconds after the ultraviolet light is turned off, all graphics turn into a bright pink phosphorescence, and the outline of the pattern is still clearly discernible; under sunlight, the printed parts exhibit a uniform light yellow color, with no obvious color difference or defects, and the hollow structure and text details are clear.

[0138] Test Example 4: Information Encryption Application Based on Phosphorescence Lifetime Differences

[0139] 1. Preparation of two phosphorescence lifetime resins

[0140] HPPF / HPA-LAD resin (long phosphorescence lifetime) and HPPF / DEF-LAD resin (short phosphorescence lifetime) were prepared according to the preparation methods of Example 1 and Comparative Example 12, respectively.

[0141] 2. 3D printing of encrypted structures

[0142] Figure 13 These are phosphorescently encoded photographs of a digital tube structure printed using a mixture of HPPF / HPA-LAD and HPPF / DEF resins at different time points. The digital tube structure was designed, with the segment marked in red printed using HPPF / DEF resin and the remaining segments printed using HPPF / HPA-LAD resin. 3D printing was performed using the optimized printing parameters from Test Example 3.

[0143] 3. Time-dependent decoding test

[0144] The printed digital tube structure was excited under 365 nm ultraviolet light for 10 seconds, and then the light source was turned off. Phosphorescence photographs were taken at different time points. The results are as follows: Figure 13As shown: (1) When the ultraviolet light is turned on, all digital tube segments emit bright blue-green fluorescence, fully displaying the numbers and time formats of "888" and "88:88"; (2) After the ultraviolet light is turned off for 0.2 seconds, all segments turn into pink phosphorescence, still clearly displaying "888" and "88:88"; (3) After the ultraviolet light is turned off for 0.6 seconds, the phosphorescence of the HPPF / DEF segment has completely decayed, while the phosphorescence of the HPPF / HPA-LAD segment is still clearly visible, thus forming a specific digital code: "235" is displayed on the left and "20:26" is displayed on the right. This time-dependent phosphorescence decay difference realizes dynamic information encoding, greatly improving the confidentiality and anti-counterfeiting level of information.

[0145] 4. 3D structure printing

[0146] Using the optimized printing parameters from Test Example 3, 3D printing was performed to produce a regular-shaped hollow 3D structure. Figure 14 SEM images of a 3D structure 3D printed using HPPF / HPA-LAD resin and photographs of the printed structure under sunlight and UV light with and without illumination. Figure 14 It can be seen that HPPF / HPA-LAD resin exhibits different colors under sunlight, with ultraviolet light on, and with ultraviolet light off.

[0147] The foregoing examples are merely illustrative, used to explain some features of the method described in this invention. The appended claims are intended to claim the broadest possible scope, and the embodiments presented herein are demonstrated by the applicant's actual experimental results. Therefore, the applicant intends that the appended claims are not limited by the selection of examples illustrating the features of the invention. Some numerical ranges used in the claims also include sub-ranges within them, and variations within these ranges should also be interpreted as being covered by the appended claims where possible.

Claims

1. A long-life room-temperature phosphorescent material, characterized in that, include: Polypropylene fumarate, hyperbranched polyester acrylate, and phosphorescent molecules; The structural formula of the phosphorescent molecule is: ； The number-average molecular weight of the poly(propylene fumarate) is 2800-4000 g / mol. Based on the total amount of polypropylene fumarate and hyperbranched polyester acrylate, the mass percentage of polypropylene fumarate is ≥58%; The total mass percentage of phosphorescent molecules is 0.08-0.15% based on the total amount of polyfuric acid propylene glycol ester and hyperbranched polyester acrylate.

2. The long-life room-temperature phosphorescent material according to claim 1, characterized in that, The polypropylene fumarate has a number-average molecular weight of 3000-3500 g / mol; and / or The phosphorescent molecules account for 0.1-0.12% of the total amount of polyfuric acid propylene glycol ester and hyperbranched polyester acrylate.

3. The long-life room-temperature phosphorescent material according to claim 1, characterized in that, The preparation method of the poly(propylene fumarate) includes the following steps: under a nitrogen atmosphere, fumarate, 1,2-propanediol, catalyst and polymerization inhibitor are mixed and polymerized to obtain bis(hydroxypropyl)fumarate diester; then further reaction is carried out to obtain the poly(propylene fumarate).

4. A method for preparing the long-lifetime room-temperature phosphorescent material according to any one of claims 1-3, characterized in that, The long-life room-temperature phosphorescent material was prepared by uniformly mixing polypropylene fumarate, hyperbranched polyester acrylate, and phosphorescent molecules.

5. A long-life room-temperature phosphorescent thin film, characterized in that, Long-life room-temperature phosphorescent films are prepared by ultraviolet curing using the long-life room-temperature phosphorescent material described in any one of claims 1-3.

6. The long-life room-temperature phosphorescent thin film according to claim 5, characterized in that, The thickness of the long-life room temperature phosphorescent film is 0.05-0.5 mm; and / or the UV curing time is ≥30 min.

7. A 3D printed part, characterized in that, The material was prepared by 3D printing using a first photocurable resin and a second photocurable resin. The first photocurable resin is the long-life room temperature phosphorescent material according to any one of claims 1-5; The phosphorescence lifetime of the first photocurable resin is 350-450 ms; the phosphorescence lifetime of the second photocurable resin is 210-310 μs.

8. The application of the long-life room temperature phosphorescent material according to any one of claims 1-3, the long-life room temperature phosphorescent film according to any one of claims 5-6, or the 3D printed part according to claim 7 in the field of information encryption and anti-counterfeiting.

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