A low-functionality photocurable resin and its preparation method
By preparing low-functionality photocurable resins and utilizing the reaction of polybenzimidazole with allyl bromide, combined with a specific ratio of crosslinking agent and photoinitiator, the compatibility problem of photocurable resins was solved, achieving improved high strength and heat resistance to meet special application requirements.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DEYI PRECISION ELECTRONIC IND CO LTD PANYU
- Filing Date
- 2024-11-26
- Publication Date
- 2026-05-26
AI Technical Summary
Existing photocurable resins have insufficient physical properties in 3D printing, especially in yield strength, tensile strength and Young's modulus. Furthermore, the poor compatibility between aliphatic crosslinking agents and aromatic macromolecules leads to phase separation and the formation of gel-like insoluble substances, which affects the resin performance.
A low-functionality photocurable resin was prepared by dissolving polybenzimidazole in a polar aprotic solvent in an inert gas atmosphere, adding sodium hydride and allyl bromide, and then drying it after irradiation with ultraviolet light using a specific ratio of crosslinking agent and photoinitiator to form a phase-free high-strength resin.
This method achieves high strength and excellent heat resistance in light-cured resins, solves the problem of poor compatibility between crosslinking agents and aromatic molecular chains, and improves the mechanical properties and curing effect of the resin.
Smart Images
Figure CN122080407A_ABST
Abstract
Description
[Technical Field]
[0001] This invention belongs to the field of polymer materials technology, specifically relating to a low-functionality photocurable resin and its preparation method. [Background Technology]
[0002] With the continuous updating and improvement of 3D printing technology, 3D printing technology and materials are being used more and more in industrial production. Among them, photopolymer 3D printing technology is favored by many companies due to its advantages of low energy consumption and high precision. However, some physical properties of photopolymer resins used in 3D printing, such as yield strength, tensile strength, Young's modulus, and elongation at break, are insufficient and cannot meet the performance requirements of some products under special application conditions.
[0003] Aromatic UV-curable resins have attracted widespread attention due to their excellent weather resistance and mechanical properties. However, a problem exists with current aromatic UV-curable resins: poor compatibility between aliphatic crosslinking agents and aromatic macromolecules. This leads to phase separation and the formation of gel-like insoluble substances, severely affecting the curing process and product properties.
[0004] Therefore, it is necessary to design an ultra-high strength photocurable resin to meet the requirements. [Summary of the Invention]
[0005] The purpose of this invention is to provide a low-functionality photocurable resin and its manufacturing method to meet the performance requirements of some products under special application conditions.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A method for preparing a low-functionality photocurable resin, characterized by comprising the following steps: dissolving polybenzimidazole in a polar aprotic solvent in an inert gas atmosphere to obtain a polybenzimidazole solution; adding sodium hydride to the polybenzimidazole solution, reacting, then adding allyl bromide, reacting again to obtain a polybenzimidazole prepolymer, wherein the molar amount of sodium hydride added is 0.8 to 1.2 times the molar amount of the polybenzimidazole resin, and the molar amount of allyl bromide added is 0.8 to 1.2 times the molar amount of the polybenzimidazole resin; dissolving the polybenzimidazole prepolymer in a polar aprotic solvent, adding a crosslinking agent and a photoinitiator, and mixing to obtain a photocurable resin solution; irradiating the photocurable resin solution with ultraviolet light, and drying to obtain a photocurable resin with a functionality of 20% to 44%.
[0008] Furthermore, the intrinsic viscosity of polybenzimidazole is 1.96–2.13 dL / g.
[0009] Furthermore, the intrinsic viscosity of the polybenzimidazole prepolymer is 1.67–1.92 dL / g.
[0010] Furthermore, the polar aprotic solvent is one or more of N-methylpyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide.
[0011] Furthermore, the crosslinking agent is one or more of pentaerythritol tetrakis(3-mercaptopropionic acid) (PETMP), ethylene glycol bis(3-mercaptopropionic acid) (ETGMP), and trimethylolpropane tri(3-mercaptopropionic acid) (TMPMP), and the amount of crosslinking agent used is 20% to 50% of the mass of the polybenzimidazole prepolymer.
[0012] Furthermore, one or more of the photoinitiators 819, 369, and TPO are used, and the amount of photoinitiator accounts for 1‰ to 8‰ of the mass of the polybenzimidazole prepolymer.
[0013] Furthermore, after adding the photoinitiator, a polymerization inhibitor is added, followed by stirring and mixing to obtain a photocurable resin solution; wherein, the polymerization inhibitor is one or more of hydroquinone, methyl hydroquinone, and tert-butyl hydroquinone, and the amount of the polymerization inhibitor is 0.35‰ to 1‰ of the mass of the polybenzimidazole prepolymer.
[0014] Furthermore, the polybenzimidazole is obtained through the following steps: In an inert gas atmosphere, equimolar amounts of 3,3′-diaminobenzidine and 4,4′-dicarboxylic acid diphenyl ether are transferred to a container, Eaton reagent is added, the temperature is raised until the solid is completely dissolved, and then the temperature is raised to 140°C and kept at that temperature for 21-27 minutes. After the reaction is complete, the mixture is poured into a sodium hydroxide solution. The crude product is filtered, washed with water, and vacuum dried to obtain polybenzimidazole.
[0015] Furthermore, a low-functionality photocurable resin is characterized in that the molecular structure of the photocurable resin is as follows:
[0016]
[0017] Where x, y, and n are positive integers, and
[0018] Furthermore, the photocurable resin has a tensile strength greater than or equal to 177 MPa.
[0019] Compared with the prior art, the present invention introduces a lower content of allyl groups into the polybenzimidazole molecular backbone, and can achieve the curing of aromatic photocurable resin with less crosslinking agent. The photocurable resin obtained by this method does not produce phase separation or gel, effectively solving the problem of poor compatibility between crosslinking agent and aromatic molecular chain. The cured photocurable resin has excellent heat resistance and ultra-high mechanical strength. [Attached Image Description]
[0020] Figure 1 The molecular structure of the photocurable resin of this invention is shown below;
[0021] Figure 2 The FTIR spectrum of the polybenzimidazole prepolymer obtained in Example 1 is shown below.
[0022] Figure 3 The FTIR spectrum of the polybenzimidazole prepolymer obtained in Example 2 is shown below.
[0023] Figure 4 The image shows the FTIR spectrum of the polybenzimidazole prepolymer obtained in Example 3.
[0024] Figure 5 The polybenzimidazole prepolymer obtained in Example 1 1 H NMR spectrum;
[0025] Figure 6 The polybenzimidazole prepolymer obtained in Example 2 1 H NMR spectrum;
[0026] Figure 7 The polybenzimidazole prepolymer obtained in Example 3 1 H NMR spectrum;
[0027] Figure 8 The DSC curve of the photocurable resin obtained in Example 1;
[0028] Figure 9 The DSC curve of the photocurable resin obtained in Example 2;
[0029] Figure 10 The DSC curve of the photocurable resin obtained in Example 3;
[0030] Figure 11 The TGA curve of the photocurable resin obtained in Example 1;
[0031] Figure 12 The TGA curve of the photocurable resin obtained in Example 2;
[0032] Figure 13 The TGA curve of the photocurable resin obtained in Example 3;
[0033] Figure 14 The stress-strain curve of the photocurable resin obtained in Example 1;
[0034] Figure 15 The stress-strain curve of the photocurable resin obtained in Example 2;
[0035] Figure 16 The stress-strain curve of the photocurable resin obtained in Example 3;
[0036] Figure 17The stress-strain curve of the photocurable resin obtained in Example 4;
[0037] Figure 18 The stress-strain curve of the photocurable resin obtained in Example 5 is shown.
Detailed Implementation Methods
[0038] To better illustrate the technical features and advantages of the present invention, a detailed description will be provided below in conjunction with specific embodiments, so that the present invention can be more easily understood by those skilled in the art, thereby providing a clearer definition of the scope of protection of the present invention.
[0039] Example 1
[0040] In an inert atmosphere (such as nitrogen), 40 mmol of 3,3′-diaminobenzidine and 40 mmol of 4,4′-dicarboxylic acid diphenyl ether were transferred to a three-necked flask, 200 mL of Eaton reagent was added, and the temperature was slowly raised to 100 °C until the solid was completely dissolved. Then the temperature was raised to 140 °C at 1 °C / min and held for 25 min. After the reaction was complete, the mixture was slowly poured into an excess of sodium hydroxide solution. The crude product was filtered, washed with water, and dried under vacuum to obtain polybenzimidazole.
[0041] In a nitrogen atmosphere, 20 mmol of the above-mentioned polybenzimidazole was transferred to a three-necked flask, and N,N-dimethylacetamide was added. The mixture was mechanically stirred at room temperature until completely dissolved to obtain a viscous polybenzimidazole solution. Then, 16 mmol of sodium hydride was added to the above system, and after sufficient reaction, 16 mmol of allyl bromide was added. The mixture was kept at 40°C for 72 h to obtain a polybenzimidazole prepolymer. The obtained photocurable resin was dissolved in N-methylpyrrolidone, and a crosslinking agent, photoinitiator, and polymerization inhibitor were added sequentially and mixed thoroughly. The mixture was then coated onto a dry and clean substrate, such as a glass plate. Irradiation with a 405 nm LED ultraviolet lamp and programmed drying were performed to obtain a photocurable resin with a functionality of 20%. Figure 1 In the structural formula,
[0042] Example 2
[0043] In a nitrogen atmosphere, 40 mmol of 3,3′-diaminobenzidine and 40 mmol of 4,4′-dicarboxylic acid diphenyl ether were transferred to a three-necked flask, 200 mL of Eaton reagent was added, and the temperature was slowly raised to 100 °C until the solid was completely dissolved. Then the temperature was raised to 140 °C at 1 °C / min and held for 25 min. After the reaction was complete, the mixture was slowly poured into an excess of sodium hydroxide solution. The crude product was filtered, washed with water, and dried under vacuum to obtain polybenzimidazole.
[0044] In a nitrogen atmosphere, 20 mmol of the above-mentioned polybenzimidazole was transferred to a three-necked flask, and N,N-dimethylacetamide was added. The mixture was mechanically stirred at room temperature until completely dissolved to obtain a viscous polybenzimidazole solution. Then, 24 mmol of sodium hydride was added to the above system, and after sufficient reaction, 24 mmol of allyl bromide was added. The mixture was kept at 40°C for 72 h to obtain a polybenzimidazole prepolymer. The obtained photocurable resin was dissolved in N-methylpyrrolidone, and a crosslinking agent, photoinitiator, and polymerization inhibitor were added sequentially. After thorough mixing, the mixture was coated onto a dry and clean substrate, irradiated with a 405 nm LED ultraviolet lamp, and then dried using a programmed drying process to obtain a photocurable resin with a functionality of 44%. Figure 1 In the structural formula,
[0045] Example 3
[0046] In a nitrogen atmosphere, 40 mmol of 3,3′-diaminobenzidine and 40 mmol of 4,4′-dicarboxylic acid diphenyl ether were transferred to a three-necked flask, 200 mL of Eaton reagent was added, and the temperature was slowly raised to 100 °C until the solid was completely dissolved. Then the temperature was raised to 140 °C at 1 °C / min and held for 25 min. After the reaction was complete, the mixture was slowly poured into an excess of sodium hydroxide solution. The crude product was filtered, washed with water, and dried under vacuum to obtain polybenzimidazole.
[0047] In a nitrogen atmosphere, 20 mmol of the above-mentioned polybenzimidazole was transferred to a three-necked flask, and N,N-dimethylacetamide was added. The mixture was mechanically stirred at room temperature until completely dissolved to obtain a viscous polybenzimidazole solution. Then, 20 mmol of sodium hydride was added to the above system, and after sufficient reaction, 20 mmol of allyl bromide was added. The mixture was kept at 40°C for 72 h to obtain a polybenzimidazole prepolymer. The obtained photocurable resin was dissolved in N-methylpyrrolidone, and a crosslinking agent, photoinitiator, and polymerization inhibitor were added sequentially. After thorough mixing, the mixture was coated onto a dry and clean substrate, irradiated with a 405 nm LED ultraviolet lamp, and then dried using a programmed drying process to obtain a photocurable resin with a functionality of 30%. Figure 1 In the structural formula,
[0048] Example 4
[0049] In a nitrogen atmosphere, 40 mmol of 3,3′-diaminobenzidine and 40 mmol of 4,4′-dicarboxylic acid diphenyl ether were transferred to a three-necked flask, 200 mL of Eaton reagent was added, and the temperature was slowly raised to 100 °C until the solid was completely dissolved. Then the temperature was raised to 140 °C at 1 °C / min and held for 21 min. After the reaction was complete, the mixture was slowly poured into an excess of sodium hydroxide solution. The crude product was filtered, washed with water, and dried under vacuum to obtain polybenzimidazole.
[0050] In a nitrogen atmosphere, 20 mmol of the above-mentioned polybenzimidazole was transferred to a three-necked flask, and N,N-dimethylacetamide was added. The mixture was mechanically stirred at room temperature until completely dissolved to obtain a viscous polybenzimidazole solution. Then, 20 mmol of sodium hydride was added to the above system, and after sufficient reaction, 20 mmol of allyl bromide was added. The mixture was kept at 40°C for 72 h to obtain a polybenzimidazole prepolymer. The obtained photocurable resin was dissolved in N-methylpyrrolidone, and a crosslinking agent, photoinitiator, and polymerization inhibitor were added sequentially. After thorough mixing, the mixture was coated onto a dry and clean substrate, irradiated with a 405 nm LED ultraviolet lamp, and then dried using a programmed drying process to obtain a photocurable resin with a functionality of 30%. Figure 1 In the structural formula,
[0051] Example 5
[0052] In a nitrogen atmosphere, 40 mmol of 3,3′-diaminobenzidine and 40 mmol of 4,4′-dicarboxylic acid diphenyl ether were transferred to a three-necked flask, 200 mL of Eaton reagent was added, and the temperature was slowly raised to 100 °C until the solid was completely dissolved. Then the temperature was raised to 140 °C at 1 °C / min and held for 27 min. After the reaction was complete, the mixture was slowly poured into an excess of sodium hydroxide solution. The crude product was filtered, washed with water, and dried under vacuum to obtain polybenzimidazole.
[0053] In a nitrogen atmosphere, 20 mmol of the above-mentioned polybenzimidazole was transferred to a three-necked flask, and N,N-dimethylacetamide was added. The mixture was mechanically stirred at room temperature until completely dissolved to obtain a viscous polybenzimidazole solution. Then, 20 mmol of sodium hydride was added to the above system, and after sufficient reaction, 20 mmol of allyl bromide was added. The mixture was kept at 40°C for 72 h to obtain a polybenzimidazole prepolymer. The obtained photocurable resin was dissolved in N-methylpyrrolidone, and a crosslinking agent, photoinitiator, and polymerization inhibitor were added sequentially. After thorough mixing, the mixture was coated onto a dry and clean substrate, irradiated with a 405 nm LED ultraviolet lamp, and then dried using a programmed drying process to obtain a photocurable resin with a functionality of 30%. Figure 1 In the structural formula,
[0054] In Examples 1-5, the crosslinking agent is one or more of pentaerythritol tetrakis(3-mercaptopropionic acid) (PETMP), ethylene glycol bis(3-mercaptopropionic acid) (ETGMP), and trimethylolpropane tris(3-mercaptopropionic acid) (TMPMP), with the following chemical formula. The amount of crosslinking agent used is 20% to 50% of the mass of the polybenzimidazole prepolymer.
[0055]
[0056]
[0057] The photoinitiator is preferably one or more of 819, 369, and TPO, with the following chemical formula. The amount of photoinitiator is 1‰ to 8‰ of the mass of the polybenzimidazole prepolymer.
[0058]
[0059] The polymerization inhibitor is one or more of hydroquinone, methyl hydroquinone, and tert-butyl hydroquinone, with the following chemical formula. The amount of polymerization inhibitor used is 0.35‰ to 1‰ of the mass of the polybenzimidazole prepolymer.
[0060]
[0061]
[0062] The intrinsic viscosities of the polybenzimidazole and polybenzimidazole prepolymers in Examples 1-5 were measured using an Ubbelohde viscometer, and the results are shown in Table 1.
[0063] Table 1
[0064]
[0065] Table 1 shows that the intrinsic viscosity of polybenzimidazole and polybenzimidazole prepolymer is related to the holding time during the polybenzimidazole preparation process. During this holding time, 3,3′-diaminobenzidine and 4,4′-dicarboxylic acid diphenyl ether undergo a polycondensation reaction. The longer the holding time, the larger the molecular weight of the obtained polybenzimidazole, and the larger the molecular weight of the final photocurable resin. Figure 1 The larger the value of n in a chemical formula.
[0066] Figure 2 , Figure 3 , Figure 4 The FTIR spectra of the polybenzimidazole prepolymers in Examples 1, 2, and 3 are shown respectively. It can be seen that the wavelengths from 3400 to 2700 cm⁻¹ are... -1 Polybenzimidazole NH (associative hydrogen bond) stretching vibrations are observed; 1620 cm⁻¹ -1 Imidazolium ring C=N stretching vibration appears; 1602 cm -1 1538cm -1 1478cm -1 1424cm -1 Aromatic ring skeleton stretching vibrations were observed; 1371 cm⁻¹ -1 CN stretching vibration occurred; 1283cm -1 Characteristic vibrations of the imidazole ring; 1239 cm -1 1170cm -1 Characteristic stretching vibration of aromatic ether bonds; 2820 cm⁻¹ -1 2980cm -1Aliphatic CH bending vibrations were observed, at 3070 cm. -1 The presence of stretching vibrations of allyl double bonds proves the existence of allyl and benzimidazole in the polybenzimidazole prepolymer.
[0067] Figure 5 , Figure 6 , Figure 7 The polybenzimidazoles in Examples 1, 2, and 3 are shown respectively. 1 1H NMR (1H NMR) spectrum, comparing the three images, shows that as the amount of allyl bromide added increases, the unreacted NH (13 ppm) in the polybenzimidazole prepolymer gradually decreases. After peak area integration and quantitative conversion, it can be seen that the functionality of the polybenzimidazole prepolymer in Examples 1, 2, and 3 are 20%, 44%, and 30%, respectively, and the functionality of the obtained photocurable resins are also 20%, 44%, and 30%, respectively.
[0068] Figure 8 , Figure 9 , Figure 10 The DSC (Differential Scanning Calorimetry) results of the photocurable resins in Examples 1, 2, and 3 are shown respectively. As can be seen from the figures, the photocurable resins obtained in Examples 1, 2, and 3 do not exhibit phase change or decomposition phenomena within 300℃, which indicates that the obtained resins have good heat resistance.
[0069] Figure 11 , Figure 12 , Figure 13 The TGA (thermal weight loss curves) of the photocurable resins in Examples 1, 2, and 3 are shown respectively. It can be seen that the thermal decomposition temperature of the obtained photocurable resins is above 320℃. The two thermal decomposition curves further confirm the existence of aliphatic allyl and aromatic polybenzimidazole macromolecular skeletons.
[0070] The stress-strain curves of the photocurable resins obtained in Examples 1-5 are shown below. The mechanical properties of the photocurable resins in Examples 1-5 were tested using a universal testing machine according to the ASTM D882 test standard. The stress-strain curves are shown below. Figures 14-18 As shown, the corresponding test data are shown in Tables 2 and 3.
[0071] Table 2
[0072]
[0073] As shown in Table 2, the tensile strength and elongation at break of the UV-cured resin increase significantly with decreasing functionality. In particular, when the functionality is 30%, all the data of the UV-cured resin reach a high level, indicating that the low-functionality UV-cured resin has extremely high mechanical strength.
[0074] Table 3
[0075]
[0076] The functionality of the photocurable resins in Examples 3-5 is 30%. Table 3 shows that when the intrinsic viscosity of the polybenzimidazole prepolymer is 1.67-1.92 dL / g at a functionality of 30%, the photocurable resin has good mechanical strength.
[0077] The above detailed description is only an illustration of a preferred embodiment of the present invention and is not intended to limit the patent scope of the present invention. Therefore, all equivalent technical changes made using the content of this invention are included within the patent scope of this invention.
Claims
1. A method for preparing a low-functionality photocurable resin, characterized in that, Includes the following steps: In an inert gas atmosphere, polybenzimidazole is dissolved in a polar aprotic solvent to obtain a polybenzimidazole solution. Sodium hydride is added to the polybenzimidazole solution, and after the reaction, allyl bromide is added. After another reaction, a polybenzimidazole prepolymer is obtained. The molar amount of sodium hydride added is 0.8 to 1.2 times the molar amount of polybenzimidazole resin, and the molar amount of allyl bromide added is 0.8 to 1.2 times the molar amount of polybenzimidazole resin. The polybenzimidazole prepolymer is dissolved in a polar aprotic solvent, and a crosslinking agent and a photoinitiator are added and mixed to obtain a photocurable resin solution. The photocurable resin solution is irradiated with ultraviolet light and dried to obtain a photocurable resin with a functionality of 20% to 44%.
2. The preparation method according to claim 1, characterized in that, The intrinsic viscosity of polybenzimidazole is 1.96–2.13 dL / g.
3. The preparation method according to claim 1, characterized in that, The intrinsic viscosity of the polybenzimidazole prepolymer is 1.67–1.92 dL / g.
4. The preparation method according to claim 1, characterized in that, The polar aprotic solvent is one or more of N-methylpyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide.
5. The preparation method according to claim 1, characterized in that, The crosslinking agent is one or more of pentaerythritol tetrakis(3-mercaptopropionic acid) (PETMP), ethylene glycol bis(3-mercaptopropionic acid) (ETGMP), and trimethylolpropane tri(3-mercaptopropionic acid) (TMPMP), and the amount of crosslinking agent used is 20% to 50% of the mass of the polybenzimidazole prepolymer.
6. The preparation method according to claim 1, characterized in that, The photoinitiator used is one or more of 819, 369, and TPO, and the amount of photoinitiator used accounts for 1‰ to 8‰ of the mass of polybenzimidazole prepolymer.
7. The preparation method according to claim 1, characterized in that, After adding the photoinitiator, a polymerization inhibitor is added, and then the mixture is stirred to obtain a photocurable resin solution. The polymerization inhibitor is one or more of hydroquinone, methyl hydroquinone, and tert-butyl hydroquinone, and the amount of the polymerization inhibitor is 0.35‰ to 1‰ of the mass of the polybenzimidazole prepolymer.
8. The preparation method according to claim 1, characterized in that, The polybenzimidazole is obtained through the following steps: In an inert gas atmosphere, equimolar amounts of 3,3′-diaminobenzidine and 4,4′-dicarboxylic acid diphenyl ether were transferred to a container, Eaton reagent was added, and the temperature was raised until the solid was completely dissolved. The temperature was then raised to 140°C and held for 21–27 min. After the reaction was complete, the mixture was poured into a sodium hydroxide solution. The crude product was filtered, washed with water, and dried under vacuum to obtain polybenzimidazole.
9. A low-functionality photocurable resin, characterized in that, The molecular structure of the photocurable resin is as follows: Where x, y, and n are positive integers, and 10. The photocurable resin as described in claim 9, characterized in that, The photocurable resin has a tensile strength greater than or equal to 177 MPa.