3D printing casting resin and preparation process thereof

Abstract

The invention discloses 3D printing casting resin and a preparation process thereof, and belongs to the technical field of resin preparation. The 3D printing casting resin is prepared from the following components in parts by weight: 50 to 72 parts of epoxy resin, 8 to 12 parts of a photocuring accelerator, 4 to 8 parts of a high-temperature-resistant additive, 1 to 3 parts of a photoinitiator, 2 to 5 parts of a flatting agent, 1 to 3 parts of a de-foaming agent and 1 to 4 parts of a stabilizer, the photocuring accelerator is prepared from abietic acid, ethoxylated trimethylolpropane triacrylate, 3-amino-1-propanol and ethylene glycol diglycidyl ether, and the high-temperature-resistant additive is prepared from trifluoroacetic acid, p-methoxyphenol, hexamethylenetetramine, 2-methylbenzimidazole and pyridine. The 3D printing casting resin prepared by the method has excellent light curing speed, high temperature resistance and mechanical property.

Description

Technical Field

[0001] The invention belongs to the technical field of resin preparation, and in particular relates to a 3D printing castable resin and a preparation process thereof. Background Art

[0002] With the rapid development of 3D printing technology, this revolutionary manufacturing method is gradually changing the face of traditional manufacturing, especially in the field of precision casting. 3D printing castable resin has become a key force in promoting industry innovation with its unique high temperature resistance, efficient photocuring molding capabilities and high customization potential.

[0003] In traditional casting processes, mold manufacturing is often time-consuming and labor-intensive, and due to the limitations of materials and technology, it is difficult to achieve precise manufacturing of complex structures. The introduction of 3D printing technology, especially in combination with the application of castable resins, has completely overturned this situation. 3D printed castable resins, as a high-performance material designed specifically for casting, not only have excellent high temperature resistance, but can also maintain structural stability in high temperature environments without deformation or degradation, ensuring the quality and precision of castings; at the same time, their excellent light-curing properties enable the resin to cure rapidly under ultraviolet or visible light. This process not only achieves precise replication of complex geometric shapes, but also greatly improves production efficiency and shortens the cycle from design to finished product.

[0004] Patent CN109880272A discloses a wax-containing 3D printing photocurable casting resin and a preparation method thereof. The wax-containing 3D printing photocurable casting resin includes the following components by weight: 30-80 parts of oligomer resin, 15-60 parts of active diluent, 1-10 parts of photoinitiator, 1-10 parts of micro powder wax, 0.1-5 parts of organic pigment, and 0.1-5 parts of leveling agent. The wax-containing 3D printing photocurable casting resin described in the invention has multiple advantages such as low viscosity, excellent mechanical properties, low ash content, and small linear shrinkage, which can effectively ensure the dimensional accuracy of the casting and its clean and smooth appearance. However, the high temperature resistance, photocuring properties, and mechanical properties of the resin prepared by this method still have room for improvement. Summary of the invention

[0005] The purpose of the present invention is to provide a 3D printable castable resin and a preparation process thereof, so as to solve the technical problems of poor high temperature resistance, photocuring performance and mechanical properties of the casting resin in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The invention provides a 3D printable castable resin, which is composed of the following components in parts by weight: 50-72 parts of epoxy resin, 8-12 parts of photocuring accelerator, 4-8 parts of high temperature resistant additive, 1-3 parts of photoinitiator, 2-5 parts of leveling agent, 1-3 parts of defoamer, and 1-4 parts of stabilizer, wherein the photocuring accelerator is prepared from rosin acid, ethoxylated trimethylolpropane triacrylate and ethylene glycol diglycidyl ether, and the high temperature resistant additive is prepared from trifluoroacetic acid, p-methoxyphenol, hexamethylenetetramine, 2-methylbenzimidazole and pyridine.

[0007] Preferably, the method for preparing the photocuring accelerator comprises the following steps: Q1: Add rosin acid, zinc chloride and oxalic acid to a container, stir mechanically under oil bath heating conditions, then cool, add ethanol, dissolve, stir and filter, add to distilled water, precipitate flocs, filter and dry to obtain a yellow powder, then add the yellow powder to dichloromethane, stir and dissolve, separate by column chromatography, and elute to obtain product 1; Q2: Add ethoxylated trimethylolpropane triacrylate and 4-methoxyphenol to a container, heat and stir, cool, drop L-alanine aqueous solution, control the drop time, react after the drop addition is completed, and obtain product 2; Q3: Add product 1, ethylene glycol diglycidyl ether and triphenylphosphine into a container, and react with mechanical stirring under oil bath conditions. After the reaction is completed, cool down, add product 2 and triphenylphosphine, and react with mechanical stirring under oil bath heating. After the reaction is completed, cool down to obtain a photocuring accelerator.

[0008] In the above process, the synthesis reaction formula of the photocuring accelerator is as follows:

[0009] The results of mass spectrometry analysis of product 1 were: m / z: 300.21 (100.0%), 301.21 (21.7%), 302.22(2.3%); the results of mass spectrometry analysis of product 2 were: m / z: 945.46 (100.0%), 946.46 (50.2%), 947.46(16.2%), 948.46 (2.1%), 948.47 (2.0%); the results of mass spectrometry analysis of photocuring accelerator were: m / z:1419.76 (100.0%), 1420.76 (81.2%), 1421.76 (38.2%), 1422.77 (8.7%), 1422.76(4.4%), 1423.77 (3.4%).

[0010] Preferably, in Q1, the dosage ratio of rosin acid, zinc chloride, oxalic acid, ethanol and distilled water is (12.1-14.5) g: (0.4-0.46) g: (0.5-0.7) g: (20-24.8) mL: (100-110) mL, the oil bath heating temperature is 180-200°C, the mechanical stirring time is 8-10 h, the temperature is lowered to 100-110°C, the drying temperature is 34-36°C, the drying time is 20-24 h, the dosage ratio of yellow powder and dichloromethane is (1.2-1.86) g: (15-18) mL, and elution is performed with a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 20:1, 10:1 and 5:1, respectively.

[0011] Preferably, in Q2, the dosage ratio of ethoxylated trimethylolpropane triacrylate, 4-methoxyphenol and L-alanine aqueous solution is (17.8-29.4) g: (0.03-0.035) g: (2.8-3.5) mL, the mass fraction of L-alanine aqueous solution is 10 wt%, the heating and stirring temperature is 70-80 ° C, the stirring speed is 200-240 rpm, the stirring time is 10-15 min, the temperature is lowered to 45-55 ° C, and the reaction time is 10-12 h.

[0012] Preferably, in Q3, the amount ratio of product 1, ethylene glycol diglycidyl ether, triphenylphosphine, product 2 and triphenylphosphine added after cooling is (14.6-17.1) g: (9.08-9.24) g: (0.43-0.45) g: (2.45-3.21) g: (0.03-0.05) g, the oil bath temperature is 120-130°C, the mechanical stirring reaction temperature is 5-7h, the temperature is cooled to 78-82°C, the oil bath heating temperature is 70-75°C, and the reaction time is 8-10h.

[0013] Preferably, the method for preparing the high temperature resistant additive comprises the following steps: S1: Add p-methoxyphenol and hexamethylenetetramine to a container containing trifluoroacetic acid, stir and dissolve, introduce nitrogen, heat and reflux to react, cool after the reaction, then add hydrochloric acid solution to continue the reaction, cool to room temperature after the reaction, filter, extract, dissolve, combine the organic phases, wash, dry, rotary evaporate, and purify to obtain intermediate compound 1; S2: Add intermediate compound 1 and 2-methylbenzimidazole to a container, add acetic anhydride and stir, introduce nitrogen, heat and stir under reflux, add deionized water after reflux, perform ultrasonic treatment, solid precipitates, filter, wash and dry to obtain intermediate compound 2; S3: Add pyridine to the intermediate compound 2, stir to dissolve, introduce nitrogen, heat and stir to reflux, cool after reflux, add deionized water to continue the reaction, cool, filter, wash the filtered solid, dry, and then repeatedly ultrasonically wash with dichloromethane to obtain a high temperature resistant additive.

[0014] In the above process, the synthesis reaction formula of the high temperature resistant additive is as follows:

[0015] The results of mass spectrometry analysis of the high temperature resistant additives were: m / z: 408.16 (100.0%), 409.16 (28.8%), 410.17 (3.6%).

[0016] Preferably, in S1, the dosage ratio of trifluoroacetic acid, p-methoxyphenol, hexamethylenetetramine and hydrochloric acid solution is (20-30) mL: (1.68-2.02) g: (6.03-6.68) g: (150-210) mL, the heating reflux reaction temperature is 110-120°C, the reflux reaction time is 70-74h, the temperature is lowered to 90-92°C, the concentration of the hydrochloric acid solution is 1 mol / L, the reaction time is continued for 20-24h, extraction is performed with dichloromethane, dissolution is performed with dichloromethane, and drying is performed with anhydrous sodium sulfate. During the purification process, a mixed solution of ethyl acetate and petroleum ether with a volume ratio of 1:10 is used as an eluent.

[0017] Preferably, in S2, the amount ratio of the intermediate compound 1, 2-methylbenzimidazole, acetic anhydride and deionized water is (0.17-0.19) g: (0.28-0.35) g: (4-6) mL: (8-12) mL, the heating stirring reflux temperature is 140-150°C, the reflux time is 56-62 h, and the mixture is washed with distilled water until neutral; in S3, the amount ratio of the intermediate compound 2, pyridine and deionized water is (0.12-0.15) g: (12-17) mL: (12-18) mL, the heating stirring reflux temperature is 110-120°C, the reflux time is 20-28 h, the temperature is lowered to 100-102°C, the reaction time is continued for 20-24 h, and the mixture is washed with distilled water.

[0018] Preferably, the preparation process of the 3D printable castable resin comprises the following steps: Step 1: Add epoxy resin, light curing accelerator and high temperature resistant additive into a container, stir and mix evenly to obtain a mixture; Step 2: Add photoinitiator, leveling agent and defoamer to the mixture, continue stirring, add stabilizer, and then degas, stand, mature, filter, and obtain 3D printing castable resin.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The present invention first uses rosin acid, ethoxylated trimethylolpropane triacrylate and ethylene glycol diglycidyl ether as raw materials to prepare a photocuring accelerator, and then uses trifluoroacetic acid, p-methoxyphenol, hexamethylenetetramine, 2-methylbenzimidazole and pyridine as raw materials to prepare a high temperature resistant additive. The photocuring accelerator and the high temperature resistant additive are added to the 3D printable castable resin, which can effectively improve its curing speed, high temperature resistance and mechanical properties.

[0020] 2. The present invention adds the prepared photocuring accelerator to the 3D printable castable resin, which can effectively improve its photocuring speed. When light is irradiated to the resin surface, the photoinitiator absorbs light energy and decomposes to produce active particles such as free radicals or cations. These particles diffuse in the resin and react with the resin functional groups to trigger a chain polymerization reaction. The light energy groups contained in the photocuring accelerator interact with the resin functional groups to promote the transfer and reaction of the active particles, and the unsaturated carbon-carbon double bonds contained in the photocuring accelerator also participate in the chain polymerization, enhancing the density and complexity of the cross-linked network. The presence of the photocuring accelerator can form more reactive sites with the resin functional groups, significantly improving the reaction rate.

[0021] 3. The present invention adds the prepared high-temperature resistant additive to the 3D printable castable resin, which can effectively improve its high-temperature resistance and mechanical properties. The high-bond energy benzimidazole ring contained in the high-temperature resistant additive can effectively increase the thermal decomposition temperature of the resin and enhance the high-temperature resistance. At the same time, the hydrogen bonds, π-π stacking and other interaction forces between molecules maintain strength at high temperatures and stabilize the resin molecular structure. In addition, the high-temperature resistant additive also has good antioxidant properties and can capture free radicals generated by the resin at high temperatures, thereby reducing the occurrence of thermal oxidative degradation. The rigid structure of the benzimidazole ring can enhance the rigidity of the resin molecular chain, thereby helping to improve the tensile strength of the resin, enabling it to withstand greater external forces without breaking. It can also act as a cross-linking point to participate in the cross-linking reaction during the resin curing process, increase the cross-linking density, form a more stable chemical bonding structure, and further enhance the mechanical properties. DETAILED DESCRIPTION

[0022] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Embodiment 1: This embodiment discloses a method for preparing a photocuring accelerator, comprising the following steps: Q1: 13.8 g of rosin acid, 0.43 g of zinc chloride and 0.6 g of oxalic acid were added to a container, mechanically stirred for 10 h under 180 °C oil bath heating conditions, then cooled to 100 °C, 22.4 mL of ethanol was added, dissolved, stirred and filtered, and then added to 105 mL of distilled water to precipitate flocs, which were filtered and dried at 36 °C for 24 h to obtain a yellow powder. Then 1.53 g of the yellow powder was added to 16.5 mL of dichloromethane, stirred and dissolved, and separated by column chromatography, eluted with a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 20:1, 10:1 and 5:1, respectively, to obtain product 1; Q2: 22.3 g of ethoxylated trimethylolpropane triacrylate and 0.033 g of 4-methoxyphenol were added to a container, heated and stirred at 70°C and 240 rpm for 15 min, cooled to 45°C, and 3.2 mL of a 10 wt% aqueous solution of L-alanine was added dropwise. The addition time was controlled. After the addition was completed, the reaction was carried out for 12 h to obtain product 2; Q3: Add 15.3g of product 1, 9.18g of ethylene glycol diglycidyl ether and 0.44g of triphenylphosphine into a container, and react with mechanical stirring for 6h under 130℃ oil bath condition. After the reaction, cool to 78℃, add 2.87g of product 2 and 0.04g of triphenylphosphine, heat in 75℃ oil bath and react with mechanical stirring for 10h. After the reaction, cool to obtain a photocuring accelerator.

[0024] This embodiment discloses a method for preparing a high temperature resistant additive, comprising the following steps: S1: Add 1.85 g of p-methoxyphenol and 6.35 g of hexamethylenetetramine to a container containing 25 mL of trifluoroacetic acid, stir and dissolve, introduce nitrogen, heat and reflux at 120°C for 72 h, cool to 90°C after the reaction, then add 180 mL of 1 mol / L hydrochloric acid solution and continue to react for 24 h. After the reaction, cool to room temperature, solid precipitates, filter, extract with dichloromethane, dissolve with dichloromethane, combine the organic phases, wash, dry with anhydrous sodium sulfate, rotary evaporate, and purify. During the purification process, a mixed solution of ethyl acetate and petroleum ether with a volume ratio of 1:10 is used as an eluent to obtain intermediate compound 1; S2: 0.18 g of intermediate compound 1 and 0.31 g of 2-methylbenzimidazole were added to a container, 5 mL of acetic anhydride was added and stirred, nitrogen was introduced, and the mixture was heated at 150° C. and stirred and refluxed for 60 h. After the reflux was completed, 10 mL of deionized water was added and ultrasonic treatment was performed. Solids were precipitated, filtered, washed with distilled water until neutral, and dried to obtain intermediate compound 2; S3: Add 14.5 mL of pyridine to 0.135 g of intermediate compound 2, stir to dissolve, introduce nitrogen, heat at 120°C with stirring and reflux for 24 h. After reflux, cool to 100°C, add 15 mL of deionized water and continue to react for 24 h. Cool, filter, wash the filtered solid with distilled water, dry, and then repeatedly ultrasonically wash with dichloromethane to obtain a high temperature resistant additive.

[0025] The present embodiment discloses a 3D printable castable resin, which is composed of the following components in parts by weight: 66 parts of epoxy resin, 10 parts of photocuring accelerator, 6 parts of high temperature resistant additive, 2 parts of benzophenone, 3.5 parts of leveling agent, 2 parts of defoaming agent, and 2.5 parts of stabilizer.

[0026] This embodiment discloses a preparation process of a 3D printable castable resin, comprising the following steps: Step 1: Add epoxy resin, light curing accelerator and high temperature resistant additive into a container, stir and mix evenly to obtain a mixture; Step 2: Add benzophenone, leveling agent and defoaming agent to the mixture, continue stirring, add stabilizer, and then degas, stand, mature, filter, and obtain 3D printing castable resin.

[0027] Embodiment 2: This embodiment discloses a method for preparing a photocuring accelerator, comprising the following steps: Q1: 12.1 g of rosin acid, 0.46 g of zinc chloride and 0.5 g of oxalic acid were added to a container, mechanically stirred for 10 h under 180 °C oil bath heating conditions, then cooled to 100 °C, 24.8 mL of ethanol was added, dissolved, stirred and filtered, and then added to 110 mL of distilled water to precipitate flocs, which were filtered and dried at 36 °C for 24 h to obtain a yellow powder. Then 1.2 g of the yellow powder was added to 15 mL of dichloromethane, stirred and dissolved, and separated by column chromatography, eluted with a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 20:1, 10:1 and 5:1, respectively, to obtain product 1; Q2: 17.8 g of ethoxylated trimethylolpropane triacrylate and 0.03 g of 4-methoxyphenol were added to a container, heated and stirred at 70°C and 240 rpm for 15 min, cooled to 45°C, and 3.5 mL of a 10 wt% aqueous solution of L-alanine was added dropwise. The addition time was controlled. After the addition was completed, the reaction was carried out for 12 h to obtain product 2; Q3: Add 14.6g of product 1, 9.08g of ethylene glycol diglycidyl ether and 0.43g of triphenylphosphine into a container, and react with mechanical stirring for 6h under 130℃ oil bath condition. After the reaction, cool to 78℃, add 2.45g of product 2 and 0.03g of triphenylphosphine, heat in 75℃ oil bath and react with mechanical stirring for 10h. After the reaction, cool to obtain a photocuring accelerator.

[0028] This embodiment discloses a method for preparing a high temperature resistant additive, comprising the following steps: S1: Add 1.68 g of p-methoxyphenol and 6.03 g of hexamethylenetetramine to a container containing 20 mL of trifluoroacetic acid, stir and dissolve, introduce nitrogen, heat and reflux at 120°C for 72 h, cool to 90°C after the reaction, then add 150 mL of 1 mol / L hydrochloric acid solution and continue to react for 24 h. After the reaction, cool to room temperature, solid precipitates, filter, extract with dichloromethane, dissolve with dichloromethane, combine the organic phases, wash, dry with anhydrous sodium sulfate, rotary evaporate, and purify. During the purification process, a mixed solution of ethyl acetate and petroleum ether with a volume ratio of 1:10 is used as an eluent to obtain intermediate compound 1; S2: 0.17 g of intermediate compound 1 and 0.28 g of 2-methylbenzimidazole were added to a container, 4 mL of acetic anhydride was added and stirred, nitrogen was introduced, and the mixture was heated at 150° C. and stirred and refluxed for 60 h. After the reflux was completed, 8 mL of deionized water was added and ultrasonic treatment was performed. Solids were precipitated, filtered, washed with distilled water until neutral, and dried to obtain intermediate compound 2; S3: Add 12 mL of pyridine to 0.12 g of intermediate compound 2, stir to dissolve, introduce nitrogen, heat at 120°C with stirring and reflux for 24 h. After reflux, cool to 100°C, add 12 mL of deionized water and continue to react for 24 h. Cool, filter, wash the filtered solid with distilled water, dry, and then repeatedly ultrasonically wash with dichloromethane to obtain a high temperature resistant additive.

[0029] The present embodiment discloses a 3D printable castable resin, which is composed of the following components in parts by weight: 50 parts of epoxy resin, 12 parts of photocuring accelerator, 4 parts of high temperature resistant additive, 1 part of benzophenone, 2 parts of leveling agent, 1 part of defoaming agent, and 1 part of stabilizer.

[0030] This embodiment discloses a preparation process of a 3D printable castable resin, comprising the following steps: Step 1: Add epoxy resin, light curing accelerator and high temperature resistant additive into a container, stir and mix evenly to obtain a mixture; Step 2: Add benzophenone, leveling agent and defoaming agent to the mixture, continue stirring, add stabilizer, and then degas, stand, mature, filter, and obtain 3D printing castable resin.

[0031] Embodiment 3: This embodiment discloses a method for preparing a photocuring accelerator, comprising the following steps: Q1: 14.5 g of rosin acid, 0.4 g of zinc chloride and 0.7 g of oxalic acid were added to a container, mechanically stirred for 10 h under 180 °C oil bath heating conditions, then cooled to 100 °C, 20 mL of ethanol was added, dissolved, stirred and filtered, and then added to 100 mL of distilled water to precipitate flocs, which were filtered and dried at 36 °C for 24 h to obtain a yellow powder. Then 1.86 g of the yellow powder was added to 18 mL of dichloromethane, stirred and dissolved, and separated by column chromatography, eluted with a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 20:1, 10:1 and 5:1, respectively, to obtain product 1; Q2: 29.4 g of ethoxylated trimethylolpropane triacrylate and 0.035 g of 4-methoxyphenol were added to a container, heated and stirred at 70°C and 240 rpm for 15 min, cooled to 45°C, and 2.8 mL of a 10 wt% aqueous solution of L-alanine was added dropwise. The addition time was controlled. After the addition was completed, the reaction was carried out for 12 h to obtain product 2; Q3: Add 17.1g of product 1, 9.24g of ethylene glycol diglycidyl ether and 0.45g of triphenylphosphine into a container, and react with mechanical stirring for 6h under 130℃ oil bath condition. After the reaction, cool to 78℃, add 3.21g of product 2 and 0.05g of triphenylphosphine, heat in 75℃ oil bath and react with mechanical stirring for 10h. After the reaction, cool to obtain a photocuring accelerator.

[0032] This embodiment discloses a method for preparing a high temperature resistant additive, comprising the following steps: S1: Add 2.02 g of p-methoxyphenol and 6.68 g of hexamethylenetetramine to a container containing 30 mL of trifluoroacetic acid, stir and dissolve, introduce nitrogen, heat and reflux at 120°C for 72 h, cool to 90°C after the reaction, then add 210 mL of 1 mol / L hydrochloric acid solution and continue to react for 24 h. After the reaction, cool to room temperature, solid precipitates, filter, extract with dichloromethane, dissolve with dichloromethane, combine the organic phases, wash, dry with anhydrous sodium sulfate, rotary evaporate, and purify. During the purification process, a mixed solution of ethyl acetate and petroleum ether with a volume ratio of 1:10 is used as an eluent to obtain intermediate compound 1; S2: 0.19 g of intermediate compound 1 and 0.35 g of 2-methylbenzimidazole were added to a container, 6 mL of acetic anhydride was added, and the mixture was stirred. Nitrogen was introduced, and the mixture was heated at 150° C. and stirred for 60 h. After the reflux, 12 mL of deionized water was added, and the mixture was ultrasonically treated. Solids were precipitated, and the solids were filtered, washed with distilled water until neutral, and dried to obtain intermediate compound 2; S3: Add 17 mL of pyridine to 0.15 g of intermediate compound 2, stir to dissolve, introduce nitrogen, heat at 120°C with stirring and reflux for 24 h. After reflux, cool to 100°C, add 18 mL of deionized water and continue to react for 24 h. Cool, filter, wash the filtered solid with distilled water, dry, and then repeatedly ultrasonically wash with dichloromethane to obtain a high temperature resistant additive.

[0033] The present embodiment discloses a 3D printing castable resin, which is composed of the following components in parts by weight: 72 parts of epoxy resin, 8 parts of light curing accelerator, 8 parts of high temperature resistant additive, 3 parts of benzophenone, 5 parts of leveling agent, 3 parts of defoaming agent, and 4 parts of stabilizer.

[0034] This embodiment discloses a preparation process of a 3D printable castable resin, comprising the following steps: Step 1: Add epoxy resin, light curing accelerator and high temperature resistant additive into a container, stir and mix evenly to obtain a mixture; Step 2: Add benzophenone, leveling agent and defoaming agent to the mixture, continue stirring, add stabilizer, and then degas, stand, mature, filter, and obtain 3D printing castable resin.

[0035] Embodiment 4: This embodiment discloses a method for preparing a photocuring accelerator, comprising the following steps: Q1: 12.9 g of rosin acid, 0.41 g of zinc chloride and 0.55 g of oxalic acid were added to a container, mechanically stirred for 10 h under 180 °C oil bath heating conditions, then cooled to 100 °C, 21.1 mL of ethanol was added, dissolved, stirred and filtered, and then added to 102 mL of distilled water to precipitate flocs, which were filtered and dried at 36 °C for 24 h to obtain a yellow powder. Then 1.34 g of the yellow powder was added to 16 mL of dichloromethane, stirred and dissolved, and separated by column chromatography, eluted with a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 20:1, 10:1 and 5:1, respectively, to obtain product 1; Q2: 19.1 g of ethoxylated trimethylolpropane triacrylate and 0.031 g of 4-methoxyphenol were added to a container, heated and stirred at 70°C and 240 rpm for 15 min, cooled to 45°C, and 2.9 mL of a 10 wt% aqueous solution of L-alanine was added dropwise. The addition time was controlled. After the addition was completed, the reaction was carried out for 12 h to obtain product 2; Q3: Add 14.9g of product 1, 9.12g of ethylene glycol diglycidyl ether and 0.43g of triphenylphosphine into a container, and react with mechanical stirring for 6h under 130℃ oil bath condition. After the reaction, cool to 78℃, add 2.61g of product 2 and 0.035g of triphenylphosphine, heat in 75℃ oil bath and react with mechanical stirring for 10h. After the reaction, cool to obtain a photocuring accelerator.

[0036] This embodiment discloses a method for preparing a high temperature resistant additive, comprising the following steps: S1: Add 1.73 g of p-methoxyphenol and 6.15 g of hexamethylenetetramine to a container containing 22 mL of trifluoroacetic acid, stir and dissolve, introduce nitrogen, heat and reflux at 120°C for 72 h, cool to 90°C after the reaction, then add 160 mL of 1 mol / L hydrochloric acid solution and continue to react for 24 h. After the reaction, cool to room temperature, solid precipitates, filter, extract with dichloromethane, dissolve with dichloromethane, combine the organic phases, wash, dry with anhydrous sodium sulfate, rotary evaporate, and purify. During the purification process, a mixed solution of ethyl acetate and petroleum ether with a volume ratio of 1:10 is used as an eluent to obtain intermediate compound 1; S2: 0.175 g of intermediate compound 1 and 0.29 g of 2-methylbenzimidazole were added to a container, 4.5 mL of acetic anhydride was added, the mixture was stirred, nitrogen was introduced, and the mixture was heated at 150° C. and stirred under reflux for 60 h. After the reflux was completed, 9 mL of deionized water was added, and ultrasonic treatment was performed. Solids were precipitated, and the solids were filtered, washed with distilled water until neutral, and dried to obtain intermediate compound 2; S3: Add 13 mL of pyridine to 0.13 g of intermediate compound 2, stir to dissolve, introduce nitrogen, heat at 120°C with stirring and reflux for 24 h. After reflux, cool to 100°C, add 13 mL of deionized water and continue to react for 24 h. Cool, filter, wash the filtered solid with distilled water, dry, and then repeatedly ultrasonically wash with dichloromethane to obtain a high temperature resistant additive.

[0037] The present embodiment discloses a 3D printable castable resin, which is composed of the following components in parts by weight: 55 parts of epoxy resin, 9 parts of light curing accelerator, 5 parts of high temperature resistant additive, 1.5 parts of benzophenone, 3 parts of leveling agent, 1.5 parts of defoaming agent, and 2 parts of stabilizer.

[0038] This embodiment discloses a preparation process of a 3D printable castable resin, comprising the following steps: Step 1: Add epoxy resin, light curing accelerator and high temperature resistant additive into a container, stir and mix evenly to obtain a mixture; Step 2: Add benzophenone, leveling agent and defoaming agent to the mixture, continue stirring, add stabilizer, and then degas, stand, mature, filter, and obtain 3D printing castable resin.

[0039] Embodiment 5: This embodiment discloses a method for preparing a photocuring accelerator, comprising the following steps: Q1: 14.1 g of rosin acid, 0.45 g of zinc chloride and 0.65 g of oxalic acid were added to a container, mechanically stirred for 10 h under 180 °C oil bath heating conditions, then cooled to 100 °C, 23.7 mL of ethanol was added, dissolved, stirred and filtered, and then added to 108 mL of distilled water to precipitate flocs, which were filtered and dried at 36 °C for 24 h to obtain a yellow powder. Then 1.68 g of the yellow powder was added to 17 mL of dichloromethane, stirred and dissolved, and separated by column chromatography, eluted with a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 20:1, 10:1 and 5:1, respectively, to obtain product 1; Q2: 27.3 g of ethoxylated trimethylolpropane triacrylate and 0.034 g of 4-methoxyphenol were added to a container, heated and stirred at 70°C and 240 rpm for 15 min, cooled to 45°C, and 3.4 mL of a 10 wt% aqueous solution of L-alanine was added dropwise. The addition time was controlled. After the addition was completed, the reaction was carried out for 12 h to obtain product 2; Q3: Add 16.2g of product 1, 9.22g of ethylene glycol diglycidyl ether and 0.45g of triphenylphosphine into a container, and react with mechanical stirring for 6h under 130℃ oil bath condition. After the reaction, cool to 78℃, add 3.05g of product 2 and 0.045g of triphenylphosphine, heat in 75℃ oil bath and react with mechanical stirring for 10h. After the reaction, cool to obtain a photocuring accelerator.

[0040] This embodiment discloses a method for preparing a high temperature resistant additive, comprising the following steps: S1: Add 1.95 g of p-methoxyphenol and 6.53 g of hexamethylenetetramine to a container containing 28 mL of trifluoroacetic acid, stir and dissolve, introduce nitrogen, heat and reflux at 120°C for 72 h, cool to 90°C after the reaction, then add 200 mL of 1 mol / L hydrochloric acid solution and continue to react for 24 h. After the reaction, cool to room temperature, solid precipitates, filter, extract with dichloromethane, dissolve with dichloromethane, combine the organic phases, wash, dry with anhydrous sodium sulfate, rotary evaporate, and purify. During the purification process, a mixed solution of ethyl acetate and petroleum ether in a volume ratio of 1:10 is used as an eluent to obtain intermediate compound 1; S2: 0.185 g of intermediate compound 1 and 0.34 g of 2-methylbenzimidazole were added to a container, 5.5 mL of acetic anhydride was added, the mixture was stirred, nitrogen was introduced, and the mixture was heated at 150° C. and stirred for 60 h. After the reflux was completed, 11 mL of deionized water was added, and ultrasonic treatment was performed. Solids were precipitated, and the solids were filtered, washed with distilled water until neutral, and dried to obtain intermediate compound 2; S3: Add 15 mL of pyridine to 0.14 g of intermediate compound 2, stir to dissolve, introduce nitrogen, heat at 120°C with stirring and reflux for 24 h. After reflux, cool to 100°C, add 16 mL of deionized water and continue to react for 24 h. Cool, filter, wash the filtered solid with distilled water, dry, and then repeatedly ultrasonically wash with dichloromethane to obtain a high temperature resistant additive.

[0041] The present embodiment discloses a 3D printable castable resin, which is composed of the following components in parts by weight: 68 parts of epoxy resin, 11 parts of photocuring accelerator, 7 parts of high temperature resistant additive, 2.5 parts of benzophenone, 4 parts of leveling agent, 2.5 parts of defoaming agent, and 3 parts of stabilizer.

[0042] This embodiment discloses a preparation process of a 3D printable castable resin, comprising the following steps: Step 1: Add epoxy resin, light curing accelerator and high temperature resistant additive into a container, stir and mix evenly to obtain a mixture; Step 2: Add benzophenone, leveling agent and defoaming agent to the mixture, continue stirring, add stabilizer, and then degas, stand, mature, filter, and obtain 3D printing castable resin.

[0043] Comparative Example 1: Compared with Example 1, in the process of preparing the photocuring accelerator in Comparative Example 1, ethoxylated trimethylolpropane triacrylate is not added, and other conditions remain unchanged.

[0044] Comparative Example 2: Compared with Example 1, in the process of preparing the high temperature resistant additive in Comparative Example 2, no p-methoxyphenol is added, and other conditions remain unchanged.

[0045] Comparative Example 3: Compared with Example 1, in the process of preparing the 3D printing castable resin in Comparative Example 3, no photocuring accelerator is added, and other conditions remain unchanged.

[0046] Comparative Example 4: Compared with Example 1, in Comparative Example 4, during the process of preparing the 3D printing castable resin, no high temperature resistant additive is added, and other conditions remain unchanged.

[0047] Experimental Example: The 3D printable castable resins prepared in Examples 1-5 and Comparative Examples 1-4 were subjected to performance tests, and the obtained samples were printed according to the SLA printing parameters in the "3D Printing Material Photocurable Resin Standard", and then light-cured, the curing time was measured, and then the tensile strength and high temperature resistance performance tests were performed on the cured samples. The tensile strength of the samples was tested according to GB / T1040.1-2018, and the high temperature resistance of the samples was tested according to GB / T 1634.1-2019. The test results are shown in Table 1: Table 1

[0048] It can be seen from the test results in Table 1 that the 3D printing castable resin prepared by Examples 1-5 of the present invention has excellent curing time, tensile strength and high temperature resistance. By comparing Comparative Example 1 with Examples 1-5, it can be seen that the addition of ethoxylated trimethylolpropane triacrylate can effectively improve the curing time of the 3D printing castable resin; by comparing Comparative Example 2 with Examples 1-5, it can be seen that the addition of p-methoxyphenol can effectively improve the tensile strength and high temperature resistance of the 3D printing castable resin; by comparing Comparative Example 3 with Examples 1-5, it can be seen that the addition of a photocuring accelerator can effectively improve the curing time of the 3D printing castable resin; by comparing Comparative Example 4 with Examples 1-5, it can be seen that the addition of a high temperature resistant additive can effectively improve the tensile strength and high temperature resistance of the 3D printing castable resin.

[0049] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0050] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A 3D printable castable resin, characterized in that: The invention is composed of the following components in parts by weight: 50-72 parts of epoxy resin, 8-12 parts of photocuring accelerator, 4-8 parts of high temperature resistant additive, 1-3 parts of photoinitiator, 2-5 parts of leveling agent, 1-3 parts of defoaming agent and 1-4 parts of stabilizer, wherein the photocuring accelerator is prepared from rosin acid, ethoxylated trimethylolpropane triacrylate and ethylene glycol diglycidyl ether, and the high temperature resistant additive is prepared from trifluoroacetic acid, p-methoxyphenol, hexamethylenetetramine, 2-methylbenzimidazole and pyridine.

2. A 3D printable castable resin according to claim 1, characterized in that: The preparation method of the photocuring accelerator comprises the following steps: Q1: Add rosin acid, zinc chloride and oxalic acid to a container, stir mechanically under oil bath heating conditions, then cool, add ethanol, dissolve, stir and filter, add to distilled water, precipitate flocs, filter and dry to obtain a yellow powder, then add the yellow powder to dichloromethane, stir and dissolve, separate by column chromatography, and elute to obtain product 1; Q2: Add ethoxylated trimethylolpropane triacrylate and 4-methoxyphenol to a container, heat and stir, cool, drop L-alanine aqueous solution, control the drop time, react after the drop addition is completed, and obtain product 2; Q3: Add product 1, ethylene glycol diglycidyl ether and triphenylphosphine into a container, and react with mechanical stirring under oil bath conditions. After the reaction is completed, cool down, add product 2 and triphenylphosphine, and react with mechanical stirring under oil bath heating. After the reaction is completed, cool down to obtain a photocuring accelerator.

3. A 3D printable castable resin according to claim 2, characterized in that: In the Q1, the dosage ratio of rosin acid, zinc chloride, oxalic acid, ethanol and distilled water is (12.1-14.5) g: (0.4-0.46) g: (0.5-0.7) g: (20-24.8) mL: (100-110) mL, the oil bath heating temperature is 180-200°C, the mechanical stirring time is 8-10 h, the temperature is lowered to 100-110°C, the drying temperature is 34-36°C, the drying time is 20-24 h, the dosage ratio of yellow powder and dichloromethane is (1.2-1.86) g: (15-18) mL, and the mixture is eluted with a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 20:1, 10:1 and 5:1, respectively.

4. A 3D printable castable resin according to claim 2, characterized in that: In Q2, the dosage ratio of ethoxylated trimethylolpropane triacrylate, 4-methoxyphenol and L-alanine aqueous solution is (17.8-29.4) g: (0.03-0.035) g: (2.8-3.5) mL, the mass fraction of L-alanine aqueous solution is 10 wt %, the heating and stirring temperature is 70-80 ° C, the stirring speed is 200-240 rpm, the stirring time is 10-15 min, the temperature is lowered to 45-55 ° C, and the reaction time is 10-12 h.

5. A 3D printable castable resin according to claim 2, characterized in that: In Q3, the dosage ratio of product 1, ethylene glycol diglycidyl ether, triphenylphosphine, product 2 and triphenylphosphine added after cooling is (14.6-17.1) g: (9.08-9.24) g: (0.43-0.45) g: (2.45-3.21) g: (0.03-0.05) g, the oil bath temperature is 120-130°C, the mechanical stirring reaction temperature is 5-7h, the temperature is cooled to 78-82°C, the oil bath heating temperature is 70-75°C, and the reaction time is 8-10h.

6. A 3D printable castable resin according to claim 1, characterized in that: The preparation method of the high temperature resistant additive comprises the following steps: S1: Add p-methoxyphenol and hexamethylenetetramine to a container containing trifluoroacetic acid, stir and dissolve, introduce nitrogen, heat and reflux to react, cool after the reaction, then add hydrochloric acid solution to continue the reaction, cool to room temperature after the reaction, filter, extract, dissolve, combine the organic phases, wash, dry, rotary evaporate, and purify to obtain intermediate compound 1; S2: Add intermediate compound 1 and 2-methylbenzimidazole to a container, add acetic anhydride and stir, introduce nitrogen, heat and stir under reflux, add deionized water after reflux, perform ultrasonic treatment, solid precipitates, filter, wash and dry to obtain intermediate compound 2; S3: Add pyridine to the intermediate compound 2, stir to dissolve, introduce nitrogen, heat and stir to reflux, cool after reflux, add deionized water to continue the reaction, cool, filter, wash the filtered solid, dry, and then repeatedly ultrasonically wash with dichloromethane to obtain a high temperature resistant additive.

7. A 3D printable castable resin according to claim 6, characterized in that: In the S1, the dosage ratio of trifluoroacetic acid, p-methoxyphenol, hexamethylenetetramine and hydrochloric acid solution is (20-30) mL: (1.68-2.02) g: (6.03-6.68) g: (150-210) mL, the heating reflux reaction temperature is 110-120° C., the reflux reaction time is 70-74 h, the temperature is lowered to 90-92° C., the concentration of the hydrochloric acid solution is 1 mol / L, the reaction time is continued for 20-24 h, extraction is performed with dichloromethane, dissolution is performed with dichloromethane, and drying is performed with anhydrous sodium sulfate. During the purification process, a mixed solution of ethyl acetate and petroleum ether in a volume ratio of 1:10 is used as an eluent.

8. A 3D printable castable resin according to claim 6, characterized in that: In S2, the amount ratio of the intermediate compound 1, 2-methylbenzimidazole, acetic anhydride and deionized water is (0.17-0.19) g: (0.28-0.35) g: (4-6) mL: (8-12) mL, the heating stirring reflux temperature is 140-150°C, the reflux time is 56-62 h, and the mixture is washed with distilled water until neutral; in S3, the amount ratio of the intermediate compound 2, pyridine and deionized water is (0.12-0.15) g: (12-17) mL: (12-18) mL, the heating stirring reflux temperature is 110-120°C, the reflux time is 20-28 h, the temperature is lowered to 100-102°C, the reaction time is continued for 20-24 h, and the mixture is washed with distilled water.

9. A process for preparing a 3D printable castable resin as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Add epoxy resin, light curing accelerator and high temperature resistant additive into a container, stir and mix evenly to obtain a mixture; Step 2: Add photoinitiator, leveling agent and defoamer to the mixture, continue stirring, add stabilizer, and then degas, stand, mature, filter, and obtain 3D printing castable resin.

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