A maleimide-based photosensitive resin and light-curing ink prepared therefrom

Abstract

The present invention discloses a maleimide-based photosensitive resin and a photocurable ink prepared therefrom. The preparation method of the maleimide-based photosensitive resin comprises the following steps: (1) adding bismaleimide to a solvent, stirring and dissolving at room temperature to obtain a mixed solution A; (2) dissolving a diamine in a solvent, stirring and dissolving at room temperature to obtain a mixed solution B; (3) under the protection of an inert gas, dropping the mixed solution B into the mixed solution A, continuously stirring for 1 to 2 hours, heating to 45 to 70° C. and stirring for 2 to 4 hours; (4) after the reaction is completed, dropping the reaction mixture into deionized water for washing, and drying to obtain the maleimide-based photosensitive resin. The ink prepared by combining the maleimide-based photosensitive resin with a photocurable monomer, a photoinitiator, and a filler can be used to obtain high-precision devices through photocurable 3D printing, and has high mechanical properties and thermal stability after thermal curing.

Description

Technical Field

[0001] The present invention relates to the technical field of photosensitive materials, in particular to a maleimide-based photosensitive resin and a photocurable ink prepared therefrom. Background Art

[0002] Stereolithography 3D printing offers advantages such as fast curing speed and high printing precision, making it suitable for producing parts and models with complex structures. However, due to the limitations of their basic properties, conventional photocurable materials are generally unsuitable for the manufacture of equipment components in fields such as aerospace. These fields place high demands on mechanical properties and thermal stability.

[0003] High-performance resins often have rigid backbones and strong intermolecular forces, making them difficult to dissolve in photocurable monomers. Consequently, high-polarity solvents are often required in the formulation of high-performance photocurable inks. Evaporation of the solvent during the curing process can lead to significant volume shrinkage, making the printing of large, high-precision components particularly challenging. Furthermore, organic solvents pose potential environmental risks, which is inconsistent with environmental protection.

[0004] Existing high-performance bismaleimide inks (a 3D printing bismaleimide ink, its preparation method, and applications; CN 109762111 A) are based on a prepolymer of bismaleimide and 2,2-diallylbisphenol A. While this improves solubility, the resulting ink has a high viscosity, making it suitable only for direct-write 3D printing and unsuitable for stereolithography and inkjet 3D printing, which require higher viscosity. High-performance polyimide inks (a polyimide photosensitive material for 3D printing; CN 105837760A) introduce photosensitive groups (glycidyl methacrylate or glycidyl acrylate) into the polyimide backbone, significantly reducing the resin's thermal stability and mechanical properties.

[0005] At present, the main issues in the current development of high-performance photocurable inks are the photosensitization of high-performance resins, the compatibility of resins with photocurable monomers, and the simultaneous improvement of the viscosity, printing accuracy, mechanical properties, and heat resistance of solvent-free photocurable inks. Summary of the Invention

[0006] To address the aforementioned issues with existing technologies, the present invention provides a maleimide-based photosensitive resin and a photocurable ink prepared therefrom. This invention utilizes the properties of maleimide groups, which are both photocurable and heat-curable, to overcome the challenges of photosensitizing high-performance resins. The prepared ink can be used to create high-precision devices through photocurable 3D printing, and exhibits high mechanical properties and thermal stability after heat curing.

[0007] The technical solutions of the present invention are as follows:

[0008] The first object of the present invention is to provide a maleimide-based photosensitive resin having a non-coplanar branched structure, and a preparation method thereof comprising the following steps:

[0009] (1) adding bismaleimide to a solvent and stirring and dissolving the mixture at room temperature to obtain a mixed solution A;

[0010] (2) dissolving the diamine in a solvent and stirring to dissolve at room temperature to obtain a mixed solution B;

[0011] (3) Under inert gas protection, add mixed solution B dropwise to mixed solution A, continue stirring for 1 to 2 hours, then heat to 45 to 70°C and stir for 2 to 4 hours;

[0012] (4) After the reaction is completed, the reaction mixture is added dropwise to deionized water for washing, and then dried to obtain the maleimide-based photosensitive resin.

[0013] In one embodiment of the present invention, in step (1), the bismaleimide is an aromatic bismaleimide;

[0014] Preferably, the bismaleimide is one or more of N,N-(4,4-methylenediphenyl)bismaleimide, N,N-m-phenylenebismaleimide, and N,N-(1,4-phenylene)bismaleimide.

[0015] In one embodiment of the present invention, in step (2), the diamine is an aliphatic diamine containing a six-membered ring structure;

[0016] Preferably, the diamine is one or more of 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, methylcyclohexanediamine, isophoronediamine, 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, and 1,6-cyclohexanediamine.

[0017] In one embodiment of the present invention, the molar ratio of the bismaleimide to the diamine is 4 to 10:1; preferably, the molar ratio of the bismaleimide to the diamine is 5:1.

[0018] In one embodiment of the present invention, in steps (1) and (2), the solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0019] A second object of the present invention is to provide a photocurable ink comprising the maleimide-based photosensitive resin, wherein the photocurable ink comprises the following raw materials in the following mass percentages:

[0020]

[0021] In one embodiment of the present invention, the photocurable monomer is one or more of trimethylolpropane triacrylate, glycerol triacrylate, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, propylene glycol diacrylate, lauryl acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, N-vinyl pyrrolidone, acryloylmorpholine, tetrahydrofuran acrylate, cyclotrimethylolpropane methylal acrylate, and isobornyl (meth)acrylate; preferably, the photocurable monomer is N-vinyl pyrrolidone or acryloylmorpholine.

[0022] In one embodiment of the present invention, the photoinitiator is a free radical photoinitiator; the filler is one or more of barium sulfate, titanium dioxide, silicon dioxide, and talc.

[0023] In one embodiment of the present invention, the free radical photoinitiator is an acylphosphine oxide; preferably, the photoinitiator is one or more of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0024] A third object of the present invention is to provide an application of the photocurable ink for 3D printing; the specific application method is: the photocurable ink is formed by photocuring 3D printing, and then subjected to thermal curing treatment to obtain a prefabricated workpiece;

[0025] The thermal curing temperature is 150-250° C., the thermal curing time is ≥4 hours, and the heating and cooling rate during the thermal curing process is less than 1° C. / min.

[0026] The beneficial technical effects of the present invention are:

[0027] The present invention uses a diamine containing a hexacyclic structure. The special spatial structure neither destroys the rigidity of the molecular main chain nor disrupts the stacking of the molecular chains, thereby obtaining good solubility so that it can be directly dissolved in a photocurable monomer to prepare a solvent-free, low-viscosity photocurable ink.

[0028] The present invention cleverly makes full use of the properties of maleimide groups, which are both photocurable and heat curable, to solve the problem of high-performance resins being difficult to photosensitize, avoids the introduction of additional photosensitive groups into the molecular chain segments, and effectively improves the thermal stability and mechanical properties of the resin.

[0029] The photocurable ink of the present invention is a solvent-free ink and is environmentally friendly; and the photocurable ink has low viscosity and good compatibility with a variety of conventional commercial 3D printers.

[0030] The photocurable ink of the present invention has a printing accuracy of up to 50 μm, which is much higher than that of ordinary commercial resins. It also has excellent mechanical properties (Young's modulus up to 4.4 GPa) and thermal stability (initial thermal decomposition temperature reaches 377°C). BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the NMR spectrum of the maleimide-based photosensitive resin described in Example 1;

[0032] Figure 2 This is the NMR spectrum of the maleimide-based photosensitive resin described in Example 2;

[0033] Figure 3 This is the NMR spectrum of the maleimide-based photosensitive resin described in Example 3;

[0034] Figure 4 This is the NMR spectrum of the maleimide-based photosensitive resin described in Example 4;

[0035] Figure 5 The viscosity test results of the inks obtained in Examples 11-14 are as follows;

[0036] Figure 6 The printing accuracy test results of the ink obtained in Example 13 are as follows;

[0037] Figure 7 This is the molecular structure diagram of the maleimide resin described in Example 2;

[0038] Figure 8 This is the molecular structure diagram of the maleimide resin described in Example 6. DETAILED DESCRIPTION

[0039] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0040] Example 1

[0041] A maleimide-based photosensitive resin, the preparation method of which comprises the following steps:

[0042] 7.17 g of N,N-(4,4-methylenediphenyl)bismaleimide was dissolved in 25.0 g of N,N-dimethylformamide and stirred at room temperature to obtain a mixed solution A;

[0043] Dissolve 0.48 g of 4,4'-diaminodicyclohexylmethane in 10.0 g of N,N-dimethylformamide, and stir to dissolve at room temperature to obtain a mixed solution B;

[0044] Under the protection of inert gas, the mixed solution B was slowly added dropwise to the mixed solution A, and after continuous stirring for 1 hour, the temperature was raised to 45° C. and stirred for 4 hours. After the reaction was completed, the reaction mixture was added dropwise to deionized water for washing, and the maleimide-based photosensitive resin was obtained after drying.

[0045] The NMR spectrum of the product is shown in Figure 1 As shown (tested according to GB / T 34247.2-2018). As can be seen from the figure, the amine proton absorption peak at 1.23 ppm disappears, and a methine hydrogen proton absorption peak adjacent to the carbonyl group appears at 3.33 ppm. The proton peaks at 7.35-2.85 ppm correspond to N,N-(4,4-methylenediphenyl)bismaleimide; the proton peak at 2.72-0.86 ppm corresponds to 4,4'-diaminodicyclohexylmethane. These analysis results confirm the successful synthesis of the target product.

[0046] Example 2

[0047] A maleimide-based photosensitive resin, the preparation method of which comprises the following steps:

[0048] 7.17 g of N,N-(4,4-methylenediphenyl)bismaleimide was dissolved in 25.0 g of N,N-dimethylformamide and stirred at room temperature to obtain a mixed solution A;

[0049] Dissolve 0.68 g of isophorone diamine in 10.0 g of N,N-dimethylformamide, and stir to dissolve at room temperature to obtain a mixed solution B;

[0050] Under the protection of inert gas, the mixed solution B was slowly added dropwise to the mixed solution A, and after continuous stirring for 2 hours, the temperature was raised to 65° C. and stirred for 2 hours. After the reaction was completed, the reaction mixture was added dropwise to deionized water for washing, and the maleimide-based photosensitive resin was obtained after drying.

[0051] The NMR spectrum of the product is shown in Figure 2 As shown in the figure, the amine proton absorption peak at 1.23 ppm disappears, and a methine hydrogen proton absorption peak adjacent to the carbonyl group appears at 3.33 ppm. The proton peaks at 7.35-2.85 ppm correspond to N,N-(4,4-methylenediphenyl)bismaleimide, while the proton peaks at 2.88-0.88 ppm correspond to isophoronediamine. These analysis results confirm the successful synthesis of the target product.

[0052] Example 3

[0053] A maleimide-based photosensitive resin, the preparation method of which comprises the following steps:

[0054] 7.17 g of N,N-(4,4-methylenediphenyl)bismaleimide was dissolved in 20.0 g of N,N-dimethylacetamide and stirred at room temperature to obtain a mixed solution A;

[0055] Dissolve 0.95 g of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane in 10.0 g of N,N-dimethylacetamide, and stir to dissolve at room temperature to obtain a mixed solution B;

[0056] Under the protection of inert gas, the mixed solution B was slowly added dropwise to the mixed solution A, and after continuous stirring for 1 hour, the temperature was raised to 50° C. and stirred for 3 hours. After the reaction was completed, the reaction mixture was added dropwise to deionized water for washing, and the maleimide-based photosensitive resin was obtained after drying.

[0057] The NMR spectrum of the product is shown in Figure 3 As shown in the figure, the amine proton absorption peak at 1.23 ppm disappears, and a methine hydrogen proton absorption peak adjacent to the carbonyl group appears at 3.33 ppm. The proton peaks at 7.35-2.85 ppm correspond to N,N-(4,4-methylenediphenyl)bismaleimide; the proton peaks at 2.72-0.94 ppm correspond to 3,3'-dimethyl-4,4-diaminodicyclohexylmethane. These analysis results confirm the successful synthesis of the target product.

[0058] Example 4

[0059] A maleimide-based photosensitive resin, the preparation method of which comprises the following steps:

[0060] 7.17 g of N,N-(4,4-methylenediphenyl)bismaleimide was dissolved in 20.0 g of N,N-dimethylacetamide and stirred at room temperature to obtain a mixed solution A;

[0061] 0.46 g of 1,2-cyclohexanediamine was dissolved in 5.0 g of N,N-dimethylacetamide, and the mixture was stirred at room temperature to dissolve to obtain a mixed solution B. Under the protection of inert gas, the mixed solution B was slowly added dropwise to the mixed solution A, and the mixture was stirred for 1 hour, and then the temperature was raised to 65° C. and stirred for 3 hours. After the reaction was completed, the reaction mixture was added dropwise to deionized water for washing, and the maleimide-based photosensitive resin was obtained after drying.

[0062] The NMR spectrum of the product is shown in Figure 4As shown in the figure, the amine proton absorption peak at 1.23 ppm disappears, and a methine hydrogen proton absorption peak adjacent to the carbonyl group appears at 3.33 ppm. The proton peaks at 7.35-2.85 ppm correspond to N,N-(4,4-methylenediphenyl)bismaleimide, while the proton peaks at 2.72-1.23 ppm correspond to 1,2-cyclohexanediamine. These analysis results confirm the successful synthesis of the target product.

[0063] Example 5

[0064] A maleimide-based photosensitive resin, the preparation method of which comprises the following steps:

[0065] 5.36 g of N,N-m-phenylene bismaleimide was dissolved in 30.0 g of N-methylpyrrolidone and stirred at room temperature to obtain a mixed solution A;

[0066] Dissolve 0.37 g of methylcyclohexanediamine in 8.0 g of N-methylpyrrolidone and stir to dissolve at room temperature to obtain a mixed solution B;

[0067] Under the protection of inert gas, the mixed solution B was slowly added dropwise to the mixed solution A, and after continuous stirring for 1 hour, the temperature was raised to 60° C. and stirred for 3 hours. After the reaction was completed, the reaction mixture was added dropwise to deionized water for washing, and the maleimide-based photosensitive resin was obtained after drying.

[0068] Example 6

[0069] A maleimide-based photosensitive resin, the preparation method of which comprises the following steps:

[0070] 5.36 g of N,N-m-phenylene bismaleimide was dissolved in 30.0 g of N-methylpyrrolidone and stirred at room temperature to obtain a mixed solution A;

[0071] Dissolve 0.33 g of 1,2-cyclohexanediamine in 7.0 g of N-methylpyrrolidone, and stir to dissolve at room temperature to obtain a mixed solution B;

[0072] Under the protection of inert gas, the mixed solution B was slowly added dropwise to the mixed solution A, and after continuous stirring for 1 hour, the temperature was raised to 60° C. and stirred for 3 hours. After the reaction was completed, the reaction mixture was added dropwise to deionized water for washing, and the maleimide-based photosensitive resin was obtained after drying.

[0073] Example 7

[0074] A maleimide-based photosensitive resin, the preparation method of which comprises the following steps:

[0075] 5.36 g of N,N-m-phenylene bismaleimide was dissolved in 28.0 g of N-methylpyrrolidone and stirred at room temperature to obtain a mixed solution A;

[0076] Dissolve 0.43 g of isophorone diamine in 10.0 g of N-methylpyrrolidone, and stir to dissolve at room temperature to obtain a mixed solution B;

[0077] Under the protection of inert gas, the mixed solution B was slowly added dropwise to the mixed solution A, and after continuous stirring for 1 hour, the temperature was raised to 60° C. and stirred for 3 hours. After the reaction was completed, the reaction mixture was added dropwise to deionized water for washing, and the maleimide-based photosensitive resin was obtained after drying.

[0078] Example 8

[0079] A maleimide-based photosensitive resin, the preparation method of which comprises the following steps:

[0080] 5.36 g of N,N-(1,4-phenylene)bismaleimide was dissolved in 25.0 g of N,N-dimethylformamide and stirred at room temperature to obtain a mixed solution A;

[0081] Dissolve 0.34 g of isophorone diamine in 10 g of N,N-dimethylformamide, and stir to dissolve at room temperature to obtain a mixed solution B;

[0082] Under the protection of inert gas, the mixed solution B was slowly added dropwise to the mixed solution A, and after continuous stirring for 1 hour, the temperature was raised to 60° C. and stirred for 3 hours. After the reaction was completed, the reaction mixture was added dropwise to deionized water for washing, and the maleimide-based photosensitive resin was obtained after drying.

[0083] Example 9

[0084] A maleimide-based photosensitive resin, the preparation method of which comprises the following steps:

[0085] 5.36 g of N,N-(1,4-phenylene)bismaleimide was dissolved in 25.0 g of N-methylpyrrolidone and stirred at room temperature to obtain a mixed solution A;

[0086] Dissolve 0.23 g of 1,6-hexanediamine in 10 g of N-methylpyrrolidone, and stir to dissolve at room temperature to obtain a mixed solution B;

[0087] Under the protection of inert gas, the mixed solution B was slowly added dropwise to the mixed solution A, and after continuous stirring for 1 hour, the temperature was raised to 60° C. and stirred for 3 hours. After the reaction was completed, the reaction mixture was added dropwise to deionized water for washing, and the maleimide-based photosensitive resin was obtained after drying.

[0088] Example 10

[0089] A maleimide-based photosensitive resin, the preparation method of which comprises the following steps:

[0090] 5.36 g of N,N-(1,4-phenylene)bismaleimide was dissolved in 25.0 g of dimethyl sulfoxide, and the mixture was stirred at room temperature to obtain a mixed solution A;

[0091] Dissolve 0.20 g of 1,4-butanediamine in 10 g of dimethyl sulfoxide, and stir to dissolve at room temperature to obtain a mixed solution B;

[0092] Under the protection of inert gas, the mixed solution B was slowly added dropwise to the mixed solution A, and after continuous stirring for 1 hour, the temperature was raised to 60° C. and stirred for 3 hours. After the reaction was completed, the reaction mixture was added dropwise to deionized water for washing, and the maleimide-based photosensitive resin was obtained after drying.

[0093] Example 11

[0094] A photocurable ink containing a maleimide-based photosensitive resin, wherein the preparation method comprises the following steps:

[0095] 50 wt% of the maleimide-based photosensitive resin described in Example 2, 41.2 wt% of N-vinyl pyrrolidone, 8.3 wt% of trimethylolpropane triacrylate, and 0.5 wt% of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide were added to a ball mill. Ceramic balls were added to the mill, the jar was sealed, and the mixture was uniformly mixed on a ball mill. Finally, the ink was passed through a 100-mesh filter to remove mechanical impurities. The ink was printed using a light-curing 3D printer (10 μm per layer, curing for 6 seconds per layer) and thermally cured at 200°C for 4 hours to produce high-performance gear workpieces and samples.

[0096] Example 12

[0097] A photocurable ink containing a maleimide-based photosensitive resin, wherein the preparation method comprises the following steps:

[0098] 40 wt% of the maleimide-based photosensitive resin described in Example 2, 44.5 wt% of N-vinyl pyrrolidone, 15 wt% of trimethylolpropane triacrylate, and 0.5 wt% of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide were added to a ball mill. Ceramic balls were added to the mill, the jar was sealed, and the mixture was uniformly mixed on a ball mill. Finally, the ink was passed through a 100-mesh filter to remove mechanical impurities. The ink was printed using a photocurable 3D printer (10 μm per layer, curing for 6 seconds per layer) and thermally cured at 200°C for 4 hours to produce high-performance gear workpieces and samples.

[0099] Example 13

[0100] A photocurable ink containing a maleimide-based photosensitive resin, wherein the preparation method comprises the following steps:

[0101] 30 wt% of the maleimide-based photosensitive resin described in Example 2, 52.0 wt% of N-vinyl pyrrolidone, 17.5% of trimethylolpropane triacrylate, and 0.5 wt% of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide were added to a ball mill. Ceramic balls were added to the mill, the jar was sealed, and the mixture was uniformly mixed on a ball mill. Finally, the ink was passed through a 100-mesh filter to remove mechanical impurities. The ink was printed using a light-curing 3D printer (10 μm per layer, curing for 6 seconds per layer) and thermally cured at 200°C for 4 hours to produce high-performance gear workpieces and samples.

[0102] Example 14

[0103] A photocurable ink containing a maleimide-based photosensitive resin, wherein the preparation method comprises the following steps:

[0104] 20 wt% of the maleimide-based photosensitive resin described in Example 2, 59.5 wt% of N-vinyl pyrrolidone, 20.0 wt% of trimethylolpropane triacrylate, and 0.5 wt% of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide were added to a ball mill. Ceramic balls were added to the mill, the jar was sealed, and the mixture was uniformly mixed on a ball mill. Finally, the ink was passed through a 100-mesh filter to remove mechanical impurities. The ink was printed using a light-curing 3D printer (10 μm per layer, curing for 8 seconds per layer) and thermally cured at 200°C for 4 hours to produce high-performance screw workpieces and samples.

[0105] Example 15

[0106] A photocurable ink containing a maleimide-based photosensitive resin, wherein the preparation method comprises the following steps:

[0107] 10 wt% of the maleimide-based photosensitive resin described in Example 4, 80 wt% of acryloylmorpholine, 5 wt% of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and 5 wt% of silica were added to a ball mill. Ceramic balls were added to the mill, the jar was sealed, and the mixture was uniformly mixed on a ball mill. Finally, the ink was passed through a 100-mesh filter to remove mechanical impurities. The ink was printed using a photocurable 3D printer (50 μm per layer, curing for 8 seconds per layer) and thermally cured at 250°C for 5 hours to produce high-performance screw workpieces and samples.

[0108] Example 16

[0109] A photocurable ink containing a maleimide-based photosensitive resin, wherein the preparation method comprises the following steps:

[0110] 70 wt% of the maleimide-based photosensitive resin described in Example 6, 20 wt% of tetrahydrofuran acrylate, 3 wt% of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and 7 wt% of titanium dioxide were added to a ball mill. Ceramic balls were added to the mill, the jar was sealed, and the mixture was uniformly mixed on a ball mill. Finally, the ink was passed through a 100-mesh filter to remove mechanical impurities. The ink was printed using a light-curing 3D printer (40 μm per layer, curing for 8 seconds per layer) and thermally cured at 150°C for 4.5 hours to produce high-performance nut workpieces and samples.

[0111] Example 17

[0112] A photocurable ink containing a maleimide-based photosensitive resin, wherein the preparation method comprises the following steps:

[0113] 60 wt% of the maleimide-based photosensitive resin described in Example 10, 30 wt% of cyclotrimethylolpropane formal acrylate, 2 wt% of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and 8 wt% of talc were added to a ball mill. Ceramic balls were added to the mill, the mill was sealed, and the mixture was uniformly mixed on a ball mill. Finally, the ink was passed through a 100-mesh filter to remove mechanical impurities. The ink was printed using a light-curing 3D printer (30 μm per layer, curing for 6 seconds per layer) and thermally cured at 180°C for 5.5 hours to produce high-performance nut workpieces and samples.

[0114] Example 18

[0115] A photocurable ink containing a maleimide-based photosensitive resin, wherein the preparation method comprises the following steps:

[0116] 36wt% of the maleimide-based photosensitive resin described in Example 2, 44.5wt% N-vinyl pyrrolidone, 15wt% trimethylolpropane triacrylate, 0.5wt% bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and 4wt% barium sulfate were added to a ball mill, sealed, and mixed thoroughly. Finally, the ink was passed through a 100-mesh filter to remove mechanical impurities. The ink was printed using a photocurable 3D printer (10μm per layer, curing for 6s per layer) and thermally cured at 200°C for 4h to produce high-performance gear workpieces and samples.

[0117] Example 19

[0118] A photocurable ink containing a maleimide-based photosensitive resin, wherein the preparation method comprises the following steps:

[0119] 36 wt% of the maleimide-based photosensitive resin described in Example 2, 44.5 wt% of N-vinylpyrrolidone, 15 wt% of trimethylolpropane triacrylate, 0.5 wt% of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 4 wt% of titanium dioxide. Add ceramic balls to the ball mill jar, seal the ball mill jar, and place it on the ball mill to mix evenly; finally, remove mechanical impurities from the ink through a 100-mesh filter screen. The ink is printed and formed by a light-curing 3D printer (10 μm per layer, cured for 6 s per layer) and heat-cured at 200 °C for 4 h to obtain high-performance gear workpieces and specimens.

[0120] Comparative Example 1

[0121] A light-curing ink, and its preparation method includes the following steps:

[0122] 30 wt% of RY1101 resin, 20 wt% of RY2252 resin, 35 wt% of N-vinylpyrrolidone, 14 wt% of trimethylolpropane triacrylate, 1 wt% of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide are added to the ball mill jar. Add ceramic balls to the ball mill jar, seal the ball mill jar, and place it on the ball mill to mix evenly; finally, remove mechanical impurities from the ink through a 100-mesh filter screen. The ink is printed and formed by a light-curing 3D printer (30 μm per layer, cured for 6 s per layer) to obtain a designed specimen.

[0123] Test Example

[0124] (1) Viscosity test: Use a rheometer to measure the viscosity of the ink at 25 °C. Select an 18-mm cone plate, and the shear rate range is 0.1 - 100 s -1 , and measure the viscosity of the sample at different shear rates. Conduct viscosity tests on Example 11, Example 12, Example 13, and Example 14 respectively. The test results are as Figure 5 shown, and the viscosity is less than 1000 mPa·s. It fully meets the requirements of ordinary commercial light-curing 3D printers.

[0125] (2) Printing accuracy test: Use a light-curing 3D printer to print a printing accuracy test board model. Observe and compare the similarity between the printed test board and the model to judge the printing accuracy. Evaluate the printing accuracy using the ink described in Example 13. Figure 6 a is a "hui" (Chinese character meaning return) - shaped structure. The clear printing of the three-dimensional structure indicates that the ink has good detail carving ability. As Figure 6 shown in b, the surface of the test board is smooth, and the detail carving is consistent with the design model. Figure 6c is a column structure with a printing accuracy of up to 50μ, indicating that the ink has high-precision depiction capabilities. In addition, d in the figure is text, g is a part of a five-pointed star, f is an Arabic numeral, and e is a conical column. These details can all be printed, which also reflects the ink's good ability to depict local details.

[0126] (3) Tensile Properties: Tested according to GB / T 1447-2005. Tensile tests were performed on the specimens (Type I) prepared in Example 12, Example 13, Example 14, Example 18, and Comparative Example 1. The test results are shown in Table 1. Example 12 exhibited a relatively high tensile strength of 80 MPa, which was much higher than the tensile strength of Comparative Example 1 (60 MPa). The data from Example 18 indicate that the addition of barium sulfate filler can effectively improve the tensile modulus of the material.

[0127] Table 1. Tensile properties test results

[0128]

[0129] (4) Dynamic thermal mechanical properties test: tested according to standard ASTM E1640-2004. Dynamic thermal mechanical properties tests were performed on Example 11, Example 12, Example 13, Example 14, Example 18, and Comparative Example 1 respectively. The test results are shown in Table 2. Among them, Example 11 showed the highest storage modulus of 4.4 GPa at room temperature, which was much higher than the 2.2 GPa of Comparative Example 1. Under high temperature conditions of 200°C, the storage modulus of Example 11 was 11 times that of Comparative Example 1, showing the potential for use under high temperature conditions. It can be seen from the data of Example 18 that the addition of barium sulfate filler can increase the modulus of the material.

[0130] Table 2. Dynamic thermomechanical properties test

[0131]

[0132] (5) Thermal Stability Test: Tested according to standard GB / T 33047.1 2016. Thermal stability tests were conducted on the products obtained in Examples 11, 12, 13, 14, 18, and Comparative Example 1. The test results are shown in Table 3. Example 11 exhibited the highest thermal stability, reaching an initial decomposition temperature of 377°C, which was much higher than the 325°C of Comparative Example 1. The data from Example 18 indicate that the addition of barium sulfate filler can improve the thermal stability of the material.

[0133] Table 3. Thermal stability test results

[0134]

[0135] (6) Density functional theory calculation: The calculation was performed using Gaussian 09 software package at the M06-2X / 6-31G(d) level. The spatial structure of the maleimide resin described in Example 2 and Example 6 was simulated and calculated. The molecular structures are shown in Figure 2 and Figure 6, respectively. Figure 7 、 Figure 8 Shown is a non-coplanar branched structure.

[0136] (7) Hardness Test: Pencil hardness was tested according to GB / T 6739-2006, and pendulum hardness was tested according to GB / T 1730-2007. Shore hardness was tested according to GB / T 531.1-2008. Hardness tests were performed on Examples 12 and 18, respectively. Table 4 shows that the addition of barium sulfate filler can effectively improve the hardness of the material.

[0137] Table 4. Hardness test results

[0138] sample Pencil hardness Pendulum hardness (s) Shore hardness Example 12 4H 132 80D Example 18 5H 156 85D

Claims

1. A photocurable ink containing a maleimide-based photosensitive resin, characterized in that: The photocurable ink comprises the following raw materials in percentage by mass: The preparation method of the maleimide-based photosensitive resin comprises the following steps: (1) adding bismaleimide to a solvent and stirring and dissolving the mixture at room temperature to obtain a mixed solution A; (2) dissolving the diamine in a solvent and stirring to dissolve at room temperature to obtain a mixed solution B; (3) Under inert gas protection, add mixed solution B dropwise to mixed solution A, continue stirring for 1 to 2 hours, then heat to 45 to 70°C and stir for 2 to 4 hours; (4) After the reaction is completed, the reaction mixture is added dropwise to deionized water for washing, and then dried to obtain the maleimide-based photosensitive resin; The filler is one or more of barium sulfate, titanium dioxide, silicon dioxide, and talc; The bismaleimide is one or more of N,N-(4,4-methylenediphenyl)bismaleimide, N,N-m-phenylenebismaleimide, and N,N-(1,4-phenylene)bismaleimide; The diamine is one or more of 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, methylcyclohexanediamine, isophoronediamine, 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, and 1,6-cyclohexanediamine.

2. The light-curable ink according to claim 1, characterized in that: The molar ratio of the bismaleimide to the diamine is 4 to 10:

1.

3. The light-curable ink according to claim 1, wherein: The molar ratio of the bismaleimide to the diamine is 5:

1.

4. The light-curable ink according to claim 1, wherein: In steps (1) and (2), the solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

5. The light-curable ink according to claim 1, wherein: The photocurable monomer is one or more of trimethylolpropane triacrylate, glycerol triacrylate, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, propylene glycol diacrylate, lauryl acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, N-vinyl pyrrolidone, acryloylmorpholine, tetrahydrofuran acrylate, cyclotrimethylolpropane formal acrylate, and isobornyl (meth)acrylate.

6. The light-curable ink according to claim 1, wherein: The photocurable monomer is N-vinyl pyrrolidone or acryloylmorpholine.

7. The light-curable ink according to claim 1, wherein: The photoinitiator is a free radical photoinitiator.

8. The light-curable ink according to claim 7, characterized in that: The free radical photoinitiator is an acylphosphine oxide.

9. The light-curable ink according to claim 7, wherein: The photoinitiator is one or more of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

10. An application of the light-curable ink according to claim 1, characterized in that: Used for 3D printing; the specific application method is: light-curing ink is formed by light-curing 3D printing, and then heat-curing treatment is performed to obtain a prefabricated workpiece; The thermal curing temperature is 150-250° C., the thermal curing time is ≥4 hours, and the heating and cooling rate during the thermal curing process is less than 1° C. / min.

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