Modified silicon dioxide enhanced photosensitive resin as well as preparation method and application thereof

Abstract

The invention provides modified silicon dioxide enhanced photosensitive resin and a preparation method and application thereof, and the modified silicon dioxide enhanced photosensitive resin comprises the following components in parts by weight: 40-70 parts of polyurethane acrylate containing large-steric-hindrance urea bonds; 20 to 40 parts of a reaction diluent; 0.5 to 5 parts of a photoinitiator; and 1-15 parts of silicon dioxide nanoparticles modified with hydroxyl or carboxyl. According to the modified silicon dioxide enhanced photosensitive resin provided by the invention, hydroxyl or carboxyl is modified on the surface of silicon dioxide, and silicon dioxide plays roles of a chain extender and a functional filler at the same time, so that the mechanical property and thermal stability of the photosensitive resin can be remarkably improved.

Description

Technical Field

[0001] This application belongs to the field of polymer materials technology, and particularly relates to a modified silica-reinforced photosensitive resin, its preparation method and application. Background Technology

[0002] Photopolymer 3D printing technologies (such as stereolithography (SLA) and digital light processing (DLP) are widely used in rapid prototyping, customized products and functional component production due to their high precision, high efficiency and excellent surface quality. As the core material of this technology, the performance of photosensitive resin directly determines the applicable scenarios of the final product.

[0003] Generally, photosensitive resins consist of a matrix resin prepolymer, reactive diluent, photoinitiator, and additives. The matrix resin prepolymer, primarily composed of polyurethane acrylate or epoxy acrylate, governs the material's fundamental properties; the reactive diluent is used to adjust parameters such as resin viscosity. However, strategies such as "increasing the molecular weight of the prepolymer" or "reducing the amount of diluent" adopted in pursuit of better performance often lead to an increase in the resin system's viscosity, thus limiting practical applications.

[0004] To address this issue, existing technologies attempt to optimize performance through a dual-curing mechanism. For example, the dual-curing photosensitive resins disclosed in CN113710713B and CN108139665B introduce a polyurethane prepolymer containing sterically hindered urea bonds and a diamine chain extender. After photocuring, the prepolymer undergoes heat treatment. At high temperatures, the prepolymer dissociates isocyanate groups, which react with the diamine chain extender to generate polyurea. This not only increases the molecular weight of the prepolymer but also forms a dual-network system with the remaining acrylate network, improving the overall performance. However, this approach still has limitations, and the improvement in the mechanical properties of the photosensitive resin material is limited. Summary of the Invention

[0005] Based on this, this application provides a modified silica-reinforced photosensitive resin, in which hydroxyl or carboxyl groups are modified on the surface of silica. Silica simultaneously acts as a chain extender and a functional filler, which can significantly improve the mechanical properties and thermal stability of the photosensitive resin.

[0006] A modified silica-reinforced photosensitive resin, comprising, by weight: 40-70 parts of polyurethane acrylate containing sterically hindered urea bonds; 20-40 parts of reaction diluent; Photoinitiator 0.5-5 parts; 1 to 10 parts of silica nanoparticles modified with hydroxyl or carboxyl groups.

[0007] The photosensitive resin provided in this application contains silica nanoparticles of 10-100 nm modified with hydroxyl or carboxyl groups. After photocuring and heat treatment, the urea bonds of the sterically hindered urea bonds in the polyurethane acrylate break and dissociate at high temperature, releasing polymers containing isocyanate groups (see...). Figure 1 As shown), the polymer isocyanate groups react with the hydroxyl or carboxyl groups on the surface of silica nanoparticles to form carbamates (see...). Figure 2 (as shown) or amide (see) Figure 3 As shown, silica nanoparticles modified with hydroxyl or carboxyl groups act as chain extenders, forming an organic-inorganic hybrid polyurethane network. This network interweaves with the remaining acrylate network to form a unique dual-network structure, which not only significantly improves the mechanical properties of the material but also effectively enhances its thermal stability.

[0008] Silica nanoparticles are surface-modified with at least two hydroxyl groups or at least two carboxyl groups. Figures 1-3 Only one, but at least two hydroxyl groups or at least two carboxyl groups are shown in the diagram, which can serve to crosslink polymers containing isocyanate groups.

[0009] Several alternative methods are provided below, but they are not intended as additional limitations on the overall solution above. They are merely further additions or optimizations. Provided there are no technical or logical contradictions, each alternative method can be combined individually with respect to the overall solution above, or multiple alternative methods can be combined with each other.

[0010] Further preferably, the photosensitive resin comprises, by weight: 40-70 parts of polyurethane acrylate containing sterically hindered urea bonds; 20-40 parts of reaction diluent; Photoinitiator 0.5-5 parts; 1 to 10 parts of silica nanoparticles modified with hydroxyl or carboxyl groups.

[0011] The general structural formula of the polyurethane acrylate containing sterically hindered urea bonds is as follows:

[0012] Among them, the wavy line " "Refers to the molecular chain. The specific structure depends on the structure of the monomers used to synthesize polyurethane acrylates. It may or may not be a carbon chain. In this application, any wavy lines in the structural formula are explained as above."

[0013] Furthermore, the polyurethane acrylate containing sterically hindered urea bonds is obtained by reacting a polyol, a polyisocyanate, and tert-butylaminoethyl methacrylate (CAS: 3775-90-4), as shown in the following reaction formula: .

[0014] Furthermore, the relationship between the molar amounts of the polyol, polyisocyanate, and tert-butylaminoethyl methacrylate is as follows: m × polyol × hydroxyl functionality + n × tert-butylaminoethyl methacrylate = k × polyisocyanate × isocyanate functionality, where m, n, and k are the molar amounts of the polyol, tert-butylaminoethyl methacrylate, and polyisocyanate, respectively, and m, n, and k are all non-zero natural numbers.

[0015] Furthermore, the polyol is one or more of polyether polyol, polyester polyol, and polycarbonate polyol.

[0016] Further, the polyisocyanate is one or more selected from hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), phenyl diisocyanate (XDI), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), cyclohexane diisocyanate (HXDI), and 4,4'-dicyclohexylmethane diisocyanate (HMDI).

[0017] Furthermore, the reaction diluent is a low-viscosity monomer of acrylate or methacrylate, which is monofunctional or polyfunctional. The type and content of the reaction diluent can be adjusted according to the requirements of mechanical properties. Preferably, the reaction diluent is one or more of isooctyl acrylate (2-EHA), polyethylene glycol diacrylate (PEGDA, Mw=200~600), isobornyl methacrylate (IBOMA), trimethylolpropane triacrylate (TMPTA), isooctyl methacrylate (EHMA), and tetrahydrofuran acrylate (THFA).

[0018] Further, the photoinitiator is at least one of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide (TMO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (photoinitiator 819), and 1-hydroxycyclohexyl benzophenone (photoinitiator 184).

[0019] Optionally, the surface of the silica nanoparticles is connected to hydroxyl or carboxyl groups via alkyl chains containing heteroatoms, wherein the alkyl chains containing heteroatoms contain a total of 6 to 14 heteroatoms and carbon atoms constituting the main chain.

[0020] Hydroxyl or carboxyl groups need to be connected to silica nanoparticles through molecular chains of a certain length. This not only improves dispersibility but also makes it easier for the hydroxyl or carboxyl groups modified on the surface of silica nanoparticles to participate in the reaction during the heat treatment stage of photosensitive resin.

[0021] See Figures 4-7 As shown, the heteroatoms in the alkyl chains containing heteroatoms are oxygen, silicon, or sulfur. See [reference needed]. Figure 5 As shown, the backbone between the silica nanoparticles and the hydroxyl groups comprises one oxygen atom, one silicon atom, one sulfur atom, and five carbon atoms. See also Figure 7 As shown, the main chain between the silica nanoparticles and the hydroxyl group includes one oxygen atom, one silicon atom, one nitrogen atom, and six carbon atoms.

[0022] Optionally, a method for preparing hydroxyl-modified silica nanoparticles includes: Step a (see Figure 4 As shown in the figure, silica nanoparticles are dispersed in toluene, and then allyltriethoxysilane is added. The mixture is reacted at 100-120°C for 4-12 hours to obtain alkenylated silica. Step b (see Figure 5 As shown, alkenylated silica was dispersed in anhydrous ethanol, then mercaptoethanol and a photoinitiator were added, and the mixture was reacted under 365nm ultraviolet light for 2-6 hours to obtain the hydroxyl-modified silica nanoparticles.

[0023] In step a, alkenyl groups are chemically grafted onto the surface of silica nanoparticles. In step b, hydroxyl groups are introduced onto the silica surface by reacting alkenyl groups with thiol groups.

[0024] Optionally, the mass ratio of the silica nanoparticles to allyltriethoxysilane is 1:0.5~1. Optionally, the molar ratio of the allyltriethoxysilane to mercaptoethanol is 1:1.05~1.2.

[0025] Specifically, the preparation method of hydroxyl-modified silica nanoparticles includes the following steps: Silica nanoparticles were ultrasonically dispersed in toluene, and 0.5 to 1 times the mass of allyltriethoxysilane was added. Under nitrogen protection, the mixture was refluxed and stirred at 100 to 120°C for 4 to 12 hours. After cooling, the mixture was washed three times by alternating centrifugation with toluene and ethanol to obtain alkenylated silica nanoparticles. The above-mentioned alkenylated silica nanoparticles were dispersed in anhydrous ethanol, and excess mercaptoethanol and a photoinitiator were added. Under nitrogen protection, the mixture was irradiated with 365 nm ultraviolet light for 2–6 hours. After the reaction was complete, the nanoparticles were washed multiple times by centrifugation with ethanol and dried under vacuum to obtain hydroxyl-modified silica nanoparticles.

[0026] Optionally, a method for preparing carboxyl-modified silica nanoparticles includes: Step A (see) Figure 6As shown in the figure, silica nanoparticles are dispersed in toluene, and then 3-aminopropyltriethoxysilane is added. The mixture is reacted at 100~120℃ for 4~12 hours to obtain aminated silica. Step B (see Figure 7 As shown, aminated silica was dispersed in anhydrous N,N-dimethylformamide, and then succinic anhydride was added. The reaction was carried out for 8 to 24 hours to obtain the silica nanoparticles modified with carboxyl groups.

[0027] In step A, amino groups are chemically grafted onto the surface of silica nanoparticles. In step b, hydroxyl groups are introduced onto the silica surface by reacting amino groups with acid anhydrides.

[0028] Optionally, the mass ratio of the silica nanoparticles to 3-aminopropyltriethoxysilane is 1:0.5~1. Optionally, the molar ratio of the 3-aminopropyltriethoxysilane to succinic anhydride is 1:1.05~1.2.

[0029] The preparation method of carboxyl-modified silica nanoparticles specifically includes the following steps: Silica nanoparticles were ultrasonically dispersed in toluene, and 0.5 to 1 times the mass of 3-aminopropyltriethoxysilane (KH-550) was added. Under nitrogen protection, the mixture was refluxed and stirred at 100 to 120°C for 4 to 12 hours. After cooling, the mixture was washed three times by alternating centrifugation with toluene and ethanol to obtain aminated silica. The above-mentioned aminated silica was dispersed in anhydrous DMF, and excess succinic anhydride was added. Under nitrogen protection, the mixture was stirred at room temperature for 8-24 hours. After the reaction was completed, the silica nanoparticles modified with carboxyl groups were washed multiple times by centrifugation with DMF and ethanol, and finally dried under vacuum.

[0030] This application also provides a method for preparing the modified silica-reinforced photosensitive resin, wherein polyurethane acrylate containing sterically hindered urea bonds, a reaction diluent, a photoinitiator, and silica nanoparticles modified with hydroxyl or carboxyl groups are sheared and dispersed at a rotation speed of 1000-2000 rpm to obtain the modified silica-reinforced photosensitive resin.

[0031] This application provides a method for processing articles using the modified silica-reinforced photosensitive resin, comprising: molding the modified silica-reinforced photosensitive resin, photocuring and heat treatment, wherein the heat treatment temperature is 100~140℃ and the time is 0.5~12h.

[0032] When using the modified silica-reinforced photosensitive resin provided in this application, it is first cured by ultraviolet light irradiation, similar to conventional photosensitive resins. At this time, the material consists of a single acrylate network, with silica nanoparticles modified with hydroxyl or carboxyl groups dispersed within it as functional fillers. The photocured material is then placed in an environment at 100~140℃ for heat treatment for 0.5~12 hours. During the heat treatment process, the sterically hindered urea bonds in the original network break and dissociate into isocyanate groups, which further react with the hydroxyl or carboxyl groups on the surface of the silica nanoparticles to generate urethane or amide. The silica nanoparticles modified with hydroxyl or carboxyl groups act as chain extenders, forming an organic-inorganic hybrid polyurethane network. This network, combined with the remaining acrylate network, forms a unique dual-network structure, which not only significantly improves the mechanical properties of the material but also effectively enhances its thermal stability.

[0033] This application also provides an application of the modified silica-reinforced photosensitive resin in 3D printing.

[0034] The photosensitive resin provided in this application retains the advantage of adjustable performance of polyurethane acrylate resin, while introducing modified silica nanoparticles with hydroxyl or carboxyl groups. The modified silica nanoparticles have good dispersibility in the resin, and the hydroxyl or carboxyl groups on the surface of the silica nanoparticles can react with isocyanate groups to form chemical bonds, thereby synergistically improving the mechanical strength, heat resistance and comprehensive physicochemical properties of the material.

[0035] Compared with the prior art, this application has the following technical effects: (1) This application proposes to graft a certain length of molecular chain with hydroxyl or carboxyl groups at the end onto the surface of silica, which not only improves its dispersibility in photosensitive resin, but also makes the hydroxyl or carboxyl groups at the end more likely to participate in the reaction process during heat treatment. (2) In this application, modified silica is used as both a functional filler and a chain extender. After heat treatment, a unique acrylate / organic-inorganic hybrid polyurethane dual network structure is obtained, which not only improves the modulus, strength and toughness of the material, but also effectively enhances the thermal stability of the material. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the high-temperature dissociation of polyurethane acrylate containing sterically hindered urea bonds. Figure 2 This is a schematic diagram showing the reaction between isocyanate groups and hydroxyl groups on the surface of silica nanoparticles to generate carbamate. Figure 3 This is a schematic diagram illustrating the reaction between isocyanate groups and carboxyl groups on the surface of silica nanoparticles to generate amides. Figure 4This is a schematic diagram of grafting alkenyl groups onto the surface of silica nanoparticles. Figure 5 This is a schematic diagram of modifying hydroxyl groups on the surface of alkenylated silica; Figure 6 This is a schematic diagram of grafting amino groups onto the surface of silica nanoparticles. Figure 7 This is a schematic diagram of modifying carboxyl groups on the surface of aminated silica. Detailed Implementation

[0037] The following provides a detailed description of the implementation methods of this application, but the scope of protection of this application is not limited thereto.

[0038] Preparation Example 1 The specific preparation steps for polyurethane acrylate prepolymers containing sterically hindered urea bonds are as follows: (1) 1000 g of polytetrahydrofuran (PTMG, Mw=1000) and 336.38 g of hexamethylene diisocyanate (HDI) were mixed evenly, and 1.13 g of dibutyltin dilaurate (DBTDL) was added. The mixture was stirred at 50°C for 4 h to obtain the isocyanate-terminated oligomer PTMG 1K-HDI; (2) 370.54 g of 2-tert-butylaminoethyl methacrylate (TBEMA) was slowly added dropwise to the above reaction system, and the mixture was stirred at 50°C for 3 h to obtain a polyurethane acrylate prepolymer PTMG 1K-HDI-TBEMA containing sterically hindered urea bonds.

[0039] Preparation Example 2 The specific preparation steps for hydroxyl-modified silica are as follows: (1) 20 g of silica nanoparticles were ultrasonically dispersed in 200 mL of toluene, and 20 g of allyltriethoxysilane was added. The mixture was refluxed and stirred at 110 °C for 8 hours under nitrogen protection. After cooling, the mixture was washed three times by alternating centrifugation with toluene and ethanol to obtain alkenylated silica.

[0040] (2) The above-mentioned alkenylated silica was dispersed in 200 mL of anhydrous ethanol, and 9.18 g of mercaptoethanol and 0.6 g of photoinitiator 184 were added. Under nitrogen protection, it was irradiated with 365 nm ultraviolet light for 6 hours. After the reaction was completed, it was washed several times by centrifugation with ethanol and dried under vacuum to obtain hydroxylated silica, denoted as SiO2-OH.

[0041] Preparation Example 3 The specific preparation steps for carboxyl-modified silica are as follows: (1) 20 g of silica nanoparticles were ultrasonically dispersed in 200 mL of toluene, and 20 g of 3-aminopropyltriethoxysilane (KH-550) was added. The mixture was refluxed and stirred at 110 °C for 8 hours under nitrogen protection. After cooling, the mixture was washed three times by alternating centrifugation with toluene and ethanol to obtain aminated silica.

[0042] (2) The above-mentioned aminated silica was dispersed in 200 mL of anhydrous DMF, and 10.85 g of succinic anhydride was added. The mixture was stirred at room temperature for 12 hours under nitrogen protection. After the reaction was completed, the silica was washed several times by centrifugation with DMF and ethanol, and finally dried under vacuum to obtain carboxylated silica, denoted as SiO2-COOH.

[0043] Examples 1-2 The PTMG 1K-HDI-TBEMA obtained in Preparation Example 1, the hydroxyl-modified silica (SiO2-OH), 2-EHA (isooctyl acrylate), PEGDA (polyethylene glycol diacrylate, Mw=400) and TPO (trimethylbenzoyl-diphenylphosphine oxide) obtained in Preparation Example 2 were weighed according to the amounts in Table 1, and then dispersed at high speed of 2000 rpm at room temperature and mixed evenly to obtain the hydroxyl-modified silica-reinforced photosensitive resin.

[0044] Table 1. Amounts of each raw material and heat treatment process in Examples 1 and 2

[0045] Examples 3-4 The PTMG 1K-HDI-TBEMA obtained in Preparation Example 1, the carboxyl-modified silica (SiO2-COOH) obtained in Preparation Example 3, 2-EHA, PEGDA (Mw=400) and TPO were weighed according to the amounts in Table 2, and then dispersed by high-speed shearing at 2000 rpm at room temperature and mixed evenly to obtain the carboxyl-modified silica-enhanced photosensitive resin.

[0046] Table 2. Amounts of each raw material and heat treatment process in Examples 3 and 4

[0047] Comparative Example 1 The PTMG 1K-HDI-TBEMA, 2-EHA, PEGDA (Mw=400) and TPO of Preparation Example 1 were weighed and mixed evenly according to the amounts in Table 3 to obtain the photosensitive resin.

[0048] Table 3. Raw material usage and heat treatment process in Comparative Example 1

[0049] Comparative Examples 2 and 3 PTMG 1K-HDI-TBEMA, silica (SiO2), 2-EHA, PEGDA (Mw=400) and TPO were weighed according to the amounts in Table 4, and then dispersed at high speed of 2000 rpm at room temperature and mixed evenly to obtain silica-dispersed photosensitive resin.

[0050] Table 4. Raw material usage and heat treatment process for Comparative Examples 2 and 3

[0051] Comparative Example 4 (1) 20g of silica nanoparticles were ultrasonically dispersed in 200mL of toluene, and 20g of allyltriethoxysilane was added. The mixture was refluxed and stirred at 110℃ for 8 hours under nitrogen protection. After cooling, the mixture was washed three times by alternating centrifugation with toluene and ethanol to obtain alkenylated silica.

[0052] (2) The above-mentioned alkenylated silica was dispersed in 200 mL of anhydrous ethanol, and 24 g of 11-mercapto-1-undecanol and 0.6 g of photoinitiator 184 were added. Under nitrogen protection, it was irradiated with 365 nm ultraviolet light for 6 hours. After the reaction was completed, it was washed several times by centrifugation with ethanol and dried under vacuum to obtain hydroxylated silica, denoted as SiO2-OH-2.

[0053] (3) The PTMG1K-HDI-TBEMA obtained in Preparation Example 1, the hydroxyl-modified silica (SiO2-OH-2) prepared above, 2-EHA, PEGDA (Mw=400) and TPO were weighed according to the amounts in Table 5, and then dispersed at high speed of 2000 rpm at room temperature and mixed evenly to obtain hydroxyl-modified silica-enhanced photosensitive resin.

[0054] Table 5. Amounts of each raw material and heat treatment process in Examples 1 and 2

[0055] Mechanical property testing The photosensitive resins prepared in Examples 1-4 and Comparative Examples 1-4 were cast into specimens conforming to ASTM D412 in transparent molds. After post-treatment according to the respective heat treatment processes in the table, the uniaxial tensile properties were tested, and the elastic modulus was calculated. The mechanical properties of each sample are shown in Table 6.

[0056] Table 6 Mechanical properties of Examples 1-4 and Comparative Examples 1-4

[0057] Comparative Example 1, serving as a blank control, did not contain any additives. Even though the hindered urea bonds with large steric hindrance dissociated into isocyanate groups during heat treatment, there were no components in the system capable of reacting with them. Therefore, the mechanical properties remained at a relatively low level. In contrast, Comparative Examples 2 and 3, which added ordinary silica, although the silica surface had a large number of hydroxyl groups, had shorter chains. In comparison, silica acted as a significant steric hindrance, hindering further reaction between the hydroxyl groups and isocyanate groups. Furthermore, due to its poor dispersibility in the resin without modification, it easily formed agglomerates within the sample when added at higher proportions, leading to a decrease in performance. In Comparative Example 4, the excessively long polymer chains on the silica surface resulted in a relatively low crosslinking density in the post-treated sample. Simultaneously, the reduced proportion of silica in the resin weakened its reinforcing effect on the material, leading to a significant decrease in material strength and modulus compared to Examples 1-4.

[0058] In stark contrast, Examples 1-4, which added modified silica, showed enhanced mechanical properties because the hydroxyl or carboxyl groups modified on the silica surface could effectively react with the isocyanate groups dissociated during heat treatment to form an organic-inorganic hybrid polyurethane network, which in turn further constructed a double network structure with the remaining acrylate network. When the proportion of modified silica added was high, although the elongation at break would decrease, the strength and modulus would still remain at a high level.

[0059] Thermal stability test After photocuring and heat-treating the photosensitive resins of Examples 1-4 and Comparative Examples 1-4, the thermogravimetric analysis was used to determine the thermogravimetric loss of the samples. The heating rate was 10°C. o C / min, the results are shown in Table 7. Table 7 records the temperatures at which each group of samples lost 10% (Td10%) and 50% (Td50%) of their weight.

[0060] Table 7. Samples from Examples 1-4 and Comparative Examples 1-4 (Td 10%) and (Td 50%)

[0061] Referring to Table 7, compared to Comparative Example 1, the heat resistance of Examples 1-4 was significantly improved. This is because the modified silica dispersed in the resin not only acts as a physical barrier to delay the escape of decomposition products and heat transfer, but also participates in the reaction, forming an organic-inorganic hybrid polyurethane network. This enhances the covalent bonds between polymer molecules, directly strengthening the ability to resist thermally induced chemical bond breakage and increasing the thermal decomposition temperature of the material. While the unmodified silica was also dispersed in the resin, its tendency to aggregate and failure to form corresponding covalent bonds with the resin system resulted in a very limited impact on the thermal decomposition temperature. In Comparative Example 4, although the modified silica could still react efficiently with the resin, its relatively low crosslinking density and silica content resulted in a relatively insignificant improvement in heat resistance.

[0062] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A modified silica-reinforced photosensitive resin, characterized in that, The photosensitive resin comprises, by weight: 40-70 parts of polyurethane acrylate containing sterically hindered urea bonds; 20-40 parts of reaction diluent; Photoinitiator 0.5-5 parts; 1-15 parts of silica nanoparticles modified with hydroxyl or carboxyl groups.

2. The modified silica-reinforced photosensitive resin according to claim 1, characterized in that, The surface of the silica nanoparticles is connected to hydroxyl or carboxyl groups through alkyl chains containing heteroatoms, and the total number of heteroatoms and carbon atoms constituting the main chain in the alkyl chains containing heteroatoms is 6 to 14.

3. The modified silica-reinforced photosensitive resin according to claim 1, characterized in that, A method for preparing hydroxyl-modified silica nanoparticles includes: Step a: Disperse silica nanoparticles in toluene, then add allyltriethoxysilane, and react at 100~120℃ for 4~12 hours to obtain alkenylated silica; Step b: Disperse alkenylated silica in anhydrous ethanol, then add mercaptoethanol and a photoinitiator, and react under 365nm ultraviolet light for 2-6 hours to obtain the modified silica nanoparticles with hydroxyl groups.

4. The modified silica-reinforced photosensitive resin according to claim 3, characterized in that, The mass ratio of the silica nanoparticles to allyltriethoxysilane is 1:0.5~1.

5. The modified silica-reinforced photosensitive resin according to claim 3, characterized in that, The molar ratio of allyltriethoxysilane to mercaptoethanol is 1:1.05~1.

2.

6. The modified silica-reinforced photosensitive resin according to claim 1, characterized in that, A method for preparing carboxyl-modified silica nanoparticles includes: Step A: Disperse silica nanoparticles in toluene, then add 3-aminopropyltriethoxysilane, and react at 100~120℃ for 4~12 hours to obtain aminated silica; Step B involves dispersing aminated silica in anhydrous N,N-dimethylformamide, then adding succinic anhydride and reacting for 8-24 hours to obtain the modified carboxyl silica nanoparticles.

7. The modified silica-reinforced photosensitive resin according to claim 6, characterized in that, The mass ratio of the silica nanoparticles to 3-aminopropyltriethoxysilane is 1:0.5~1.

8. The modified silica-reinforced photosensitive resin according to claim 6, characterized in that, The molar ratio of 3-aminopropyltriethoxysilane to succinic anhydride is 1:1.05~1.

2.

9. A method for preparing a modified silica-reinforced photosensitive resin as described in any one of claims 1 to 8, characterized in that, The modified silica-reinforced photosensitive resin is obtained by shearing and dispersing polyurethane acrylate containing sterically hindered urea bonds, reaction diluent, photoinitiator, and silica nanoparticles modified with hydroxyl or carboxyl groups at a rotation speed of 1000-2000 rpm.

10. A method for processing articles using the modified silica-reinforced photosensitive resin according to any one of claims 1 to 8, characterized in that, include: The modified silica-reinforced photosensitive resin is molded, photocured, and heat-treated, wherein the heat treatment temperature is 100~140℃ and the time is 0.5~12h.

Images