Fluorescent resin composition of hybrid system and application of fluorescent resin composition in 3D printing

Abstract

The invention discloses a fluorescent resin composition of a hybrid system and application of the fluorescent resin composition in 3D printing, an epoxy fluorescent monomer has excellent light stability and can be connected into resin molecules in an epoxy polymerization mode, the stability is greatly improved, and the service life of a material is prolonged. In addition, due to the characteristic absorption of the epoxy monomer on 355 nm ultraviolet light, scattering of exciting light can be effectively inhibited, and the printing precision is improved. The epoxy monomer can also be subjected to [2 + 2] cycloaddition reaction under the irradiation of 400 nm ultraviolet light, a four-membered ring structure is formed, an original conjugated system is changed, the photochromic function and the erasable property are achieved, no chemical consumption exists in the conversion process, and the service cycle is obviously prolonged.

Description

Technical Field

[0001] This invention relates to the field of 3D printing materials technology, specifically to a hybrid fluorescent resin composition and its application in 3D printing. Background Technology

[0002] 3D printing is a technology that creates three-dimensional objects by layering materials, essentially transforming a digital model into a physical entity. Compared to traditional computer numerical control (CNC) technology, 3D printing offers advantages such as lower equipment costs, lower technical barriers to entry, and shorter production cycles, making it widely used in aerospace, automotive, dental, medical, and footwear industries, among others.

[0003] Stereolithography (SLA) technology has garnered widespread attention due to its advantages over other 3D printing technologies, namely high forming accuracy and good surface quality. The development of high-precision printing materials is the foundation and prerequisite for achieving precision manufacturing. Currently, adding UV absorbers to the formulation is a common method to improve printing accuracy. The principle is to absorb scattered UV light from the resin, thereby inhibiting free radical diffusion and controlling the cross-linking reaction within the exposed area. Commonly available UV absorbers, such as benzophenone and benzotriazole, generally suffer from poor photostability and compatibility issues with the resin matrix. Under prolonged exposure to UV light, the molecular structure of UV absorbers is easily damaged, losing its light absorption effect and affecting the surface quality and structural consistency of the printed parts. Due to the additive manufacturing nature of 3D printing, leftover materials can be reused, resulting in a long resin lifespan and placing high demands on material stability.

[0004] Photoluminescence refers to the phenomenon where electrons in a substance transition to an excited state after absorbing light radiation of a specific wavelength. The process of light emitting light from a light source to its ground state is a physical process in which the light emits energy in the form of light. This process can be applied to the field of anti-counterfeiting, so that anti-counterfeiting labels can only be displayed or change color when excited by a special light source. The light emission process has no chemical consumption, is repeatable, and has strong concealment.

[0005] If a fluorescent epoxy monomer with ultraviolet absorption function is to be designed, issues such as photostability and resin compatibility must be fully considered. Therefore, this invention is proposed. Summary of the Invention

[0006] This invention provides epoxy fluorescent monomer compounds to address the problems of poor photoluminescence stability and poor resin compatibility in existing technologies, thereby promoting their application in the field of 3D printing.

[0007] In view of this, the solution of the present invention is as follows: The first aspect of the present invention is to provide an epoxy fluorescent monomer compound having the structural formula shown in Formula I: .

[0008] A second aspect of the present invention is to provide a method for preparing the epoxy fluorescent monomer compound described in the first aspect, comprising the steps of: S1,4-bromomethylbenzoate reacts with triphenylphosphine to give a phosphorus ylide intermediate; S2. Phosphorus ylide intermediate reacts with 1-pyrene carbaldehyde under strong alkaline conditions to give a pyrene-enyl methyl terephthalate derivative having the structural formula shown in Formula II; S3. The pyrenenyl p-benzoate methyl ester derivative was reduced to obtain the pyrenenyl p-benzophenol derivative; S4. The reaction of pyrenenyl p-benzophenol derivatives with epichlorohydrin yields an epoxy fluorescent monomer compound; The structural formula of Formula II is: .

[0009] Further, in step S1, the molar ratio of methyl 4-bromomethylbenzoate and triphenylphosphine is 1:(1.1-1.2).

[0010] Furthermore, in step S2: The molar ratio of the phosphorus ylide intermediate to 1-pyrene carbaldehyde is 1:(1.1-1.2). And / or, in step S2, the strong base is a tert-butoxide salt, and it is added dropwise; And / or, in step S2, the reaction process is carried out at room temperature; And / or, in step S2, after the reaction is completed, the reaction solution is quenched, extracted, the organic phase is dried, rotary evaporated, and purified by column chromatography to obtain the epoxy fluorescent monomer compound shown in Formula I.

[0011] A third aspect of the invention is to provide the application of a hybrid fluorescent resin composition in 3D printing, said fluorescent resin composition comprising the epoxy fluorescent monomer compound described in the first aspect, and monomers or oligomers capable of undergoing chain growth reactions therewith.

[0012] A fourth aspect of the present invention is to provide a hybrid fluorescent resin composition comprising, by weight: 5-20 parts of epoxy fluorescent monomer; 10-30 parts of epoxy reactive diluent; 20-40 parts of epoxy oligomer; 20-40 parts of acrylate reactive diluent; 1-3 parts of cationic photoinitiator; 1-3 parts of free radical photoinitiator; and 0.2-2 parts of additives; wherein the epoxy fluorescent monomer is the epoxy fluorescent monomer compound described in the first aspect.

[0013] Furthermore, in the above fluorescent resin composition: The epoxy reactive diluent is selected from one or more of glycidyl ether, 1,4-butanediol diglycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarbamate, and neopentyl glycol diglycidyl ether. And / or, the epoxy oligomer is selected from one or more of bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol F type epoxy resin, and phenolic epoxy resin; And / or, the acrylate reactive diluent is selected from one or more of tris(2-hydroxyethyl)isocyanurate triacrylate (THEICTA), pentaerythritol triacrylate (PETA), and dipentaerythritol hexaacrylate (DPHA).

[0014] Furthermore, the cationic photoinitiator is selected from one or a combination of two of 4,4'-dimethyldiphenyliodonium hexafluorophosphate and diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate.

[0015] Furthermore, the free radical photoinitiator is one or a combination of two of diphenyl-(2,4,6-trimethylbenzoyl)phosphine and 1-hydroxy-cyclohexyl-phenyl ketone.

[0016] Furthermore, the additives include defoamers and / or leveling agents. Preferably, based on the mass fraction of the fluorescent resin composition, the amount of both the defoamer and the leveling agent is 0.1-1 parts. Preferably, the defoamer is BYK-306 from BAK Chemicals (Germany), and the leveling agent is BYK-333 from BAK Chemicals (Germany).

[0017] A fifth aspect of the present invention is to provide a 3D printed article, characterized in that it is made by 3D printing and photocuring from the fluorescent resin composition described in the fourth aspect.

[0018] A sixth aspect of the present invention is to provide the application of the fluorescent resin composition described in the fourth aspect or the 3D printed article described in the fifth aspect in the field of optical information erasure and writing, including but not limited to use in aerospace, automotive, dental, medical, footwear and other fields, as well as for information encryption and anti-counterfeiting labels.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The epoxy fluorescent monomer provided by this invention exhibits excellent photostability and can be incorporated into resin molecules via epoxy polymerization, avoiding problems such as aggregation, settling, and floating of fluorescent molecules during storage and printing, thus greatly improving stability and extending the material's lifespan. Furthermore, due to the characteristic absorption of 355 nm ultraviolet light by this epoxy monomer, it can effectively suppress the scattering of excitation light, improving printing accuracy. Under 400 nm ultraviolet light irradiation, this epoxy monomer can also undergo a [2+2] pericyclic addition reaction to form a four-membered ring structure, altering the original conjugated system and exhibiting photochromic properties and erasability. This conversion process involves no chemical consumption, therefore the input and write of encrypted information can be repeated hundreds of times, significantly extending the lifespan.

[0020] Attached Description

[0021] Figure 1 This invention illustrates the fluorescent erasable and rewritable effects of fluorescent epoxy monomers used in 3D printing under different wavelengths of irradiation. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described in conjunction with preferred embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In one embodiment, a method for preparing an epoxy fluorescent monomer compound is provided, comprising the following steps: 1. Synthesis of Phosphorus Ylide Intermediates 4-Bromomethylbenzoate and triphenylphosphine (molar ratio 1:1.1-1.2) were added to a round-bottom flask, and toluene was added as a solvent. The mixture was refluxed under a nitrogen atmosphere for 12 h. After the reaction was completed, the mixture was cooled, and a large amount of solid precipitated from the reaction solution. The solid was filtered, and the filter cake was washed with cyclohexane and dried to obtain the phosphorus ylide intermediate. No further purification was required, and the yield was over 83%. The reaction process is as follows:

[0024] 2. Synthesis of pyrenenyl methyl benzoate derivatives

[0025] The phosphorus ylide intermediate synthesized in step one and 1-pyrenecarboxaldehyde (molar ratio 1:1.1-1.2) were added to a round-bottom flask. Tetrahydrofuran was added as a solvent, and a solution of potassium tert-butoxide in tetrahydrofuran was slowly added dropwise under nitrogen atmosphere. After the addition was complete, the reaction was allowed to proceed at room temperature for 6 h. After the reaction was completed, the mixture was quenched with a saturated ammonium chloride aqueous solution and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, and purified by column chromatography after rotary evaporation to obtain the pyrene-enyl methyl terephthalate derivative (Formula II) in a yield of over 86%. The reaction process is as follows:

[0026] 3. Synthesis of pyrenenyl p-benzophenol derivatives

[0027] The pyrene-based methyl terephthalate derivative was dissolved in dry dichloromethane and cooled to -78 °C. Under nitrogen atmosphere, diisobutylaluminum hydride (1 M in dry dichloromethane) was slowly added dropwise. After the addition was complete, the mixture was stirred at -78 °C for 2 h. After the reaction was complete, distilled water was added to quench the reaction. The reaction solution was washed with distilled water and saturated brine, respectively. The organic phase was dried over anhydrous sodium sulfate and then rotary evaporated to obtain the pyrene-based terephthalophenol derivative in a yield of over 87%. The reaction process is as follows:

[0028] 4. Synthesis of fluorescent epoxy monomers

[0029] The pyrene-based p-cresol derivative and sodium hydroxide (molar ratio 1:1.1-1.2) were added to dry acetone and stirred at 45°C for 20 min to dissolve most of the solid. Epichlorohydrin was then slowly added dropwise under nitrogen atmosphere. After the addition was complete, stirring continued for 3 h. After the reaction was complete, the mixture was cooled to room temperature, filtered, and washed with a small amount of acetone. The filtrate was concentrated by rotary evaporation and purified by column chromatography to obtain the target product, a fluorescent epoxy monomer (Formula I), with a yield of up to 80%. The reaction route is as follows:

[0030] In the above embodiments, the fluorescent epoxy monomer compound of Formula I not only possesses excellent photostability but also participates in the epoxy reaction, exhibiting good compatibility with the resin matrix and significantly improving the storage and usage stability of the printing material. Simultaneously, the epoxy reaction effectively mitigates the volume shrinkage caused by acrylic resin polymerization, further enhancing printing accuracy. Furthermore, because this epoxy monomer can undergo reversible photoinduced [2+2] pericyclic and ring-opening reactions, the material also possesses potential information encryption capabilities and excellent erasability / rewriteability.

[0031] In another embodiment, a high-precision 3D printing fluorescent material comprising a fluorescent epoxy monomer compound of the above Formula I is proposed. The epoxy fluorescent monomer, epoxy reactive diluent, epoxy oligomer, acrylate reactive diluent, cationic photoinitiator, free radical photoinitiator, defoamer and leveling agent are added to a container, stirred for 30 minutes, and allowed to stand to defoam to obtain the high-precision 3D printing fluorescent material.

[0032] Because the fluorescent monomer shown in Formula I possesses excellent photostability and can be incorporated into resin molecules via epoxy polymerization, problems such as aggregation, settling, and floating of fluorescent molecules during storage and printing are avoided, greatly improving stability and extending the material's lifespan. Furthermore, due to the characteristic absorption of this epoxy monomer at 355 nm ultraviolet light, it can effectively suppress the scattering of excitation light, improving printing accuracy. Under 400 nm ultraviolet light irradiation, this epoxy monomer can also undergo a [2+2] pericyclic addition reaction to form a four-membered ring structure, altering the original conjugated system and exhibiting photochromic properties. It also possesses erasability (the four-membered ring opens upon irradiation with 365 nm ultraviolet light, reverting to the original structure). This conversion process involves no chemical consumption, therefore the input and write of encrypted information can be repeated hundreds of times. The specific mechanism is as follows:

[0033] When the printed material is placed in a dark environment and irradiated with a mercury lamp, it produces a blue-green fluorescence. If the printed material is irradiated with a 400 nm wavelength LED UV lamp for five minutes, the fluorescence gradually turns blue, exhibiting a blue shift (the fluorescence wavelength shifts towards shorter wavelengths). This is because the pericyclic reaction causes the exocyclic double bond of the pyrene ring to disappear, weakening the π-conjugation of the fluorophore and leading to the blue shift. If the printed material is irradiated with a 365 nm wavelength LED, the exocyclic double bond is restored, and the fluorescence gradually returns to blue-green (e.g., ...). Figure 1 (As shown).

[0034] In some embodiments, the high-precision 3D printing fluorescent material comprises, by weight, 5-20 parts of epoxy fluorescent monomer; 10-30 parts of epoxy reactive diluent; 20-40 parts of epoxy oligomer; 20-40 parts of acrylate reactive diluent; 1-3 parts of cationic photoinitiator; 1-3 parts of free radical photoinitiator; 0.1-1 part of defoamer; and 0.1-1 part of leveling agent.

[0035] In a preferred embodiment, the epoxy reactive diluent is one or a combination of two resins selected from glycidyl ether, 1,4-butanediol diglycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarbamate, and neopentyl glycol diglycidyl ether.

[0036] In a preferred embodiment, the epoxy oligomer is one or a combination of two of the following resins: dimethyl methacrylate (DMA) epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol F type epoxy resin, and phenolic epoxy resin.

[0037] In a preferred embodiment, the acrylate reactive diluent is one or a combination of tris(2-hydroxyethyl) isocyanurate triacrylate (THEICTA), pentaerythritol triacrylate (PETA), and dipentaerythritol hexaacrylate (DPHA).

[0038] In a preferred embodiment, the cationic photoinitiator is one or a combination of two of 4,4'-dimethyldiphenyliodonium hexafluorophosphate and diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate.

[0039] In a preferred embodiment, the free radical photoinitiator is one or a combination of two of diphenyl-(2,4,6-trimethylbenzoyl)phosphine and 1-hydroxy-cyclohexyl-phenyl ketone.

[0040] In a preferred embodiment, the defoamer is BYK-306 from BAK Chemicals (Germany), and the leveling agent is BYK-333 from BAK Chemicals (Germany).

[0041] In some embodiments, the above-mentioned high-precision 3D printing fluorescent material can be printed using an SLA printer, with the specific printing parameters as follows: 1. Laser wavelength: 355 nm; 2. Laser power: 200-400 mW, preferably 300 mW; 3. Scanning speed: 1000-3000 mm / s, preferably 2000 mm / s; 4. Layer thickness: 50-100 μm, preferably 100 μm.

[0042] In the above embodiments, the ultraviolet absorption function of the epoxy fluorescent monomer is used to improve the printing precision of the high-precision 3D printing fluorescent material, and it has good photostability, is not easily decomposed by light during the printing process, and is suitable for long-term use. It also has photochromic properties and is erasable, making it suitable for applications such as information encryption and document anti-counterfeiting.

[0043] Example 1

[0044] 1. Preparation of fluorescent epoxy monomers

[0045] 1) Methyl 4-bromomethylbenzoate (11.45 g, 50 mmol) and triphenylphosphine (15.74 g, 60 mmol) were added to a 500 mL round-bottom flask, along with 200 mL of toluene as a solvent. The mixture was refluxed under a nitrogen atmosphere for 12 h. After the reaction was complete, the mixture was cooled to room temperature and then placed in an ice-water bath. A large amount of solid precipitated from the reaction solution. The solid was filtered, and the filter cake was washed with cyclohexane and dried to obtain the phosphorus ylide intermediate (20.5 g, 41.72 mmol), with a yield of 83.44%, requiring no further purification.

[0046] 2) The phosphorus ylide intermediate synthesized in step 1 (19.66 g, 40 mmol) and 1-pyrenecarboxaldehyde (11.15 g, 48 mmol) synthesized in step 1 were added to a 500 mL round-bottom flask, and 150 mL of tetrahydrofuran was added to form a suspension. Potassium tert-butoxide (5.38 g, 48 mmol) was dissolved in 50 mL of tetrahydrofuran and slowly added dropwise to the suspension under nitrogen atmosphere. After the addition was complete, the reaction was carried out at room temperature for 6 h. After the reaction was completed, the mixture was quenched with saturated ammonium chloride aqueous solution and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, and purified by column chromatography (eluent: dichloromethane / n-hexane = 1 / 4) after rotary evaporation to obtain the pyrene-enyl methyl terephthalate derivative (12.54 g, 34.6 mmol), with a yield of 86.5%.

[0047] 3) A pyrene-based methyl terephthalate derivative (10.87 g, 30 mmol) was dissolved in 150 mL of anhydrous dichloromethane. The solution was cooled to -78 °C and, under nitrogen atmosphere, diisobutylaluminum hydride (75 mL, 1 M in anhydrous dichloromethane) was slowly added dropwise. After the addition was complete, the mixture was stirred for 2 h in an acetone-ice bath. After the reaction was complete, the mixture was kept at a low temperature and distilled water was slowly added to quench the reaction. The reaction mixture was transferred to a separatory funnel and washed with distilled water and saturated brine, respectively. The organic phase was dried over anhydrous sodium sulfate and then rotary evaporated to obtain a pyrene-based terephthalophenol derivative (8.33 g, 26 mmol), with a yield of 87.06%.

[0048] 4) Pyrene-based p-cresol derivative (8 g, 25 mmol) and sodium hydroxide (1.12 g, 28 mmol) were added to 50 mL of dry acetone and stirred at 45 °C for 20 min to dissolve most of the solid. Epichlorohydrin (2.59 g, 28 mmol) was slowly added dropwise under nitrogen atmosphere. After the addition was complete, stirring was continued at 45 °C for 3 h. After the reaction was complete, the system was cooled to room temperature, and the reaction solution was filtered through a Buchner funnel to remove the inorganic salts generated during the reaction. The filter residue was washed with a small amount of acetone. The filtrate was concentrated by rotary evaporation to obtain a viscous crude product. The crude product was purified by column chromatography (eluting agent: ethyl acetate / petroleum ether = 1 / 5) to obtain the target product, fluorescent epoxy monomer (7.45 g, 19.8 mmol), with a yield of 79.84%.

[0049] 2. Preparation of high-precision 3D printing fluorescent materials

[0050] The synthesized epoxy fluorescent monomer, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, bisphenol A epoxy resin, tri(2-hydroxyethyl)isocyanurate triacrylate, diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxyphosphate (TPO), BYK-306, and BYK-333 were stirred at room temperature for 30 minutes to disperse evenly according to the mass proportions in Table 1, and then allowed to stand to defoam.

[0051] Example 2

[0052] 1. Preparation of fluorescent epoxy monomers

[0053] Steps 1 to 3): are the same as steps one to three in Example 1.

[0054] 4) Add 8 g (25 mmol) of pyrene-based p-cresol derivative and 1 g (25 mmol) of sodium hydroxide to 50 mL of dry acetone and stir at 45 °C for 20 min to dissolve most of the solid. Then, under nitrogen atmosphere, slowly add epichlorohydrin (2.59 g, 28 mmol). After the addition is complete, continue stirring at 45 °C for 3 h. After the reaction is complete, no inorganic salts precipitate, and epoxy value testing confirms that almost no epoxy ring is formed in the system, indicating that the reaction has failed. This is because when the equivalent ratio of sodium hydroxide to pyrene-based p-cresol derivative is 1:1, there is no excess sodium hydroxide to provide the alkaline conditions required for the elimination reaction after ring opening, making ring closure impossible. Add 0.12 g of sodium hydroxide to the system and continue stirring for 1.5 h. After the reaction is complete, allow the system to cool to room temperature, filter the reaction solution using a Buchner funnel to remove the inorganic salts generated during the reaction, and wash the filter residue with a small amount of acetone. The filtrate was concentrated by rotary evaporation to obtain a viscous crude product. The crude product was purified by column chromatography (eluting agent: ethyl acetate / petroleum ether = 1 / 5) to obtain the target product, a fluorescent epoxy monomer (6.51 g, 17.3 mmol), with a yield of 76.89%.

[0055] 2. Preparation of high-precision 3D printing fluorescent materials

[0056] The synthesized epoxy fluorescent monomer, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, bisphenol A epoxy resin, tri(2-hydroxyethyl)isocyanurate triacrylate, diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxyphosphate (TPO), BYK-306, and BYK-333 were stirred at room temperature for 30 minutes to disperse evenly according to the mass proportions in Table 1, and then allowed to stand to defoam.

[0057] Example 3

[0058] 1. Preparation of fluorescent epoxy monomers

[0059] 1) Same as step 1) in Example 1.

[0060] 2) In a 500 mL round-bottom flask, the phosphorus ylide intermediate synthesized in step 1 (19.66 g, 40 mmol) and 1-pyrenecarboxaldehyde (11.15 g, 48 mmol) were added, followed by the addition of 150 mL of tetrahydrofuran to form a suspension. Sodium hydroxide (1.92 g, 48 mmol) was dissolved in 50 mL of tetrahydrofuran and slowly added dropwise to the suspension under nitrogen atmosphere. After the addition was complete, the reaction was allowed to proceed at room temperature for 6 h. Thin-layer chromatography (TLC) was used to monitor the reaction; no product was formed. The reaction failed because the sodium hydroxide was not sufficiently basic to remove the α-H atom of the phosphorus atom.

[0061] Comparative Example 1

[0062] 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, bisphenol A epoxy resin, tri(2-hydroxyethyl)isocyanurate triacrylate, diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxyphosphate (TPO), BYK-306, BYK-333, and rhodamine B were stirred at room temperature for 60 minutes to disperse evenly according to the mass proportions in Table 1, and then allowed to stand to defoam.

[0063] Comparative Example 2

[0064] 3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, bisphenol A epoxy resin, tri(2-hydroxyethyl)isocyanurate triacrylate, diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxyphosphate (TPO), BYK-306, BYK-333, and 2-hydroxy-4-methoxybenzophenone were stirred at room temperature for 30 minutes to disperse evenly according to the mass proportions in Table 1, and then allowed to stand to defoam.

[0065] Comparative Example 3

[0066] 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, bisphenol A epoxy resin, tri(2-hydroxyethyl)isocyanurate triacrylate, diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxyphosphate (TPO), BYK-306, BYK-333, 2-hydroxy-4-methoxybenzophenone, and rhodamine B were stirred at room temperature for 60 minutes to disperse evenly according to the mass proportions in Table 1, and then allowed to stand to defoam.

[0067] Comparative Example 4

[0068] 1. Double bond reduction of epoxy fluorescent monomer

[0069] The fluorescent epoxy monomer (0.376 g, 1 mmol) prepared in the examples and 30 mg Wilkinson catalyst RhCl (PP) were used. The catalyst was added to a Schlenk reaction tube, along with 10 mL of anhydrous toluene as solvent. The tube was then purged with hydrogen to replace the air. The reaction was carried out in an oil bath at 40 °C for 3 hours, and the reaction progress was monitored by TLC. After the reaction was complete, the Wilkinson catalyst was filtered off, and the filtrate was concentrated by rotary evaporation to obtain an oily crude product. The crude product was purified by column chromatography (eluting agent: ethyl acetate / petroleum ether = 1 / 5) to obtain a double-bond reduced epoxy fluorescent monomer.

[0070] The double-bond reduced epoxy fluorescent monomer, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, bisphenol A epoxy resin, tri(2-hydroxyethyl)isocyanurate triacrylate, diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxyphosphate (TPO), BYK-306, and BYK-333 were stirred at room temperature for 30 minutes to disperse evenly according to the mass ratios in Table 1, and then allowed to stand to defoam.

[0071] Table 1: Dosage of each component of the 3D printing material in each embodiment and comparative example

[0072] Test case

[0073] Photostability testing method: All materials except the photoinitiator were premixed according to the formulations in Examples 1, 2, and Comparative Examples 1, 2, and 3, and stirred for 30 minutes. After thorough mixing, the mixture was irradiated with a high-pressure mercury lamp (wavelength 365 nm) for 2 hours, with continuous stirring. After irradiation, the photoinitiator was added, and the mixture was stirred for another 10 minutes to obtain a photostability test printing material. Thin films with a thickness of 0.5 mm were printed using the printing materials from Examples 1, 2, and Comparative Examples 1, 2, and 3, and the corresponding photostability test printing materials, respectively, under the same parameters. After cleaning and curing, the film thicknesses were compared. The smaller the difference in film thickness, the less the UV absorber was decomposed by light irradiation, and the better the photostability.

[0074] Liquid stability test method: Take 100 g of printing material from each example and comparative example, place it in a closed oven at 60℃, and age for 7 days. Observe whether there are any phenomena such as layering, precipitation, sedimentation, or agglomeration. The more uniform the material phase after aging, the better its liquid stability.

[0075] All 3D printing operations involved in this invention were performed on the UnionTech Lite100. After printing, the prints were cleaned with alcohol and dried, then cured in a curing chamber using 355 nm ultraviolet light for 30 minutes. The printing and testing results are shown in Table 1, and the specific printing parameters are as follows: 1. Laser wavelength: 355 nm; 2. Laser power: 300 mW; 3. Scanning speed: 2000 mm / s; 4. Layer thickness: 100μm.

[0076] Table 1: Printing and testing results of various embodiments and comparative examples

[0077] Erasability verification: The high-precision printing materials from Examples 1 and 2 were used to print desktop ornaments. The printed objects were placed in a dark environment, and when illuminated with a mercury lamp, they produced a blue-green fluorescence. After illuminating the printed objects with a 400 nm wavelength LED ultraviolet lamp for five minutes, the fluorescence gradually turned blue. Subsequently, when the printed objects were illuminated with a 365 nm wavelength LED, the fluorescence gradually returned to blue-green (effect as shown in the image). Figure 1 The process could be repeated multiple times within 2 hours of testing, and no significant decrease in fluorescence intensity was observed.

[0078] By comparing Examples 1 and 2 with Comparative Examples 1, 2, and 3, it can be seen that the fluorescent epoxy monomer synthesized in this invention can act as a UV absorber, 2-hydroxy-4-methoxybenzophenone, reducing the thickness of the film (except for Comparative Example 1, the film thickness is reduced to below 0.5 mm). This indicates that the monomer has strong UV absorption function and suppresses the scattering of excitation light in the resin. The addition of Rhodamine B, however, cannot reduce the film thickness because its UV absorption peak is around 550 nm, and it has almost no absorption effect on excitation light at 355 nm.

[0079] By comparing Examples 1 and 2 with Comparative Examples 2 and 3, the difference in the thickness of the film before and after illumination in Examples 1 and 2 was smaller, indicating that the epoxy fluorescent monomer decomposed less after 2 hours of high-pressure mercury lamp irradiation, had good photostability, and could still maintain strong ultraviolet absorption function.

[0080] Comparing Examples 1 and 2 with Comparative Examples 1 and 3, the addition of Rhodamine B significantly affected the liquid stability of the printing material. After 7 days of aging, observation under UV light clearly showed that Rhodamine B aggregation led to uneven fluorescence. Similarly, the fluorescent epoxy monomer, which also has photoluminescence function, showed better compatibility with the resin matrix, and no phase separation or aggregation was observed under UV light after 7 days of aging.

[0081] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An epoxy fluorescent monomer compound, characterized in that, It has the structural formula shown in Equation I: 。 2. The method for preparing the epoxy fluorescent monomer compound according to claim 1, characterized in that, step include: S1,4-bromomethylbenzoate reacts with triphenylphosphine to give a phosphorus ylide intermediate; S2. Phosphorus ylide intermediate reacts with 1-pyrene carbaldehyde under strong alkaline conditions to give a pyrene-enyl methyl terephthalate derivative having the structural formula shown in Formula II; S3. The pyrenenyl p-benzoate methyl ester derivative was reduced to obtain the pyrenenyl p-benzophenol derivative; S4. The reaction of pyrenenyl p-benzophenol derivatives with epichlorohydrin yields an epoxy fluorescent monomer compound; The structural formula of Formula II is: 。 3. The preparation method according to claim 2, characterized in that, In step S1, the molar ratio of methyl 4-bromomethylbenzoate to triphenylphosphine is 1:(1.1-1.2). And / or, in step S2, the molar ratio of the phosphorus ylide intermediate to 1-pyrene carbaldehyde is 1:(1.1-1.2). And / or, in step S2, the strong base is a tert-butoxide salt, and it is added dropwise; And / or, in step S2, the reaction process is carried out at room temperature; And / or, in step S2, after the reaction is completed, the reaction solution is quenched, extracted, the organic phase is dried, rotary evaporated, and purified by column chromatography to obtain the epoxy fluorescent monomer compound shown in Formula I.

4. The application of a hybrid fluorescent resin composition in 3D printing, characterized in that, The fluorescent resin composition includes the epoxy fluorescent monomer compound of claim 1, and monomers or oligomers capable of undergoing chain growth reactions therewith.

5. A fluorescent resin composition of a hybrid system, characterized in that, The components, by weight, include: 5-20 parts of epoxy fluorescent monomer; 10-30 parts of epoxy reactive diluent; 20-40 parts of epoxy oligomer; 20-40 parts of acrylate reactive diluent; 1-3 parts of cationic photoinitiator; 1-3 parts of free radical photoinitiator; and 0.2-2 parts of additives; wherein the epoxy fluorescent monomer is the epoxy fluorescent monomer compound as described in claim 1.

6. The fluorescent resin composition according to claim 5, characterized in that, The epoxy reactive diluent is selected from one or more of glycidyl ether, 1,4-butanediol diglycidyl ether, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarbamate, and neopentyl glycol diglycidyl ether. And / or, the epoxy oligomer is selected from one or more of bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol F type epoxy resin, and phenolic epoxy resin; And / or, the acrylate reactive diluent is selected from one or more of tris(2-hydroxyethyl)isocyanurate triacrylate (THEICTA), pentaerythritol triacrylate (PETA), and dipentaerythritol hexaacrylate (DPHA).

7. The fluorescent resin composition according to claim 5, characterized in that, The cationic photoinitiator is selected from one or a combination of two of 4,4'-dimethyldiphenyliodonium hexafluorophosphate and diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate; And / or, the free radical photoinitiator is one or a combination of two of diphenyl-(2,4,6-trimethylbenzoyl)phosphine and 1-hydroxy-cyclohexyl-phenyl ketone.

8. The fluorescent resin composition according to claim 5, characterized in that, The additives include defoamers and / or leveling agents.

9. A 3D printed product, characterized in that, It is made by 3D printing and photocuring of the fluorescent resin composition according to any one of claims 5-8.

10. The application of the fluorescent resin composition according to any one of claims 5-8 or the 3D printed article according to claim 9 in the field of optical information erasure and writing.

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