A single-component 3D printing photosensitive resin, elastomer material and preparation method

Abstract

The present invention provides a single-component 3D printing photosensitive resin, an elastomeric material, and a preparation method, relating to the field of 3D printing technology. The single-component 3D printing photosensitive resin comprises the following raw materials, measured by mass: 10-25 parts of a blocked diisocyanate, 30-70 parts of an acrylic acid-modified polyamine, 20-40 parts of a reactive diluent, and 2-5 parts of a photoinitiator; the structural formula of the blocked diisocyanate is shown in Formula I, and the structural formula of the acrylic acid-modified polyamine is shown in Formula II. The dual curing process of the single-component 3D printing photosensitive resin system of the present invention combines the rapid prototyping advantages of photocuring and the deep chain extension advantages of thermal curing, so that the finally obtained elastomeric material has a higher molecular weight and better mechanical properties.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing technology, and in particular to a single-component 3D printing photosensitive resin, an elastomer material and a preparation method thereof. Background Art

[0002] Currently, 3D printing photosensitive resin elastomer materials are widely used in flexible electronics, biomedicine, soft robotics, and other fields, and a two-component curing strategy is commonly used. Patent CN 114479001 A discloses a two-component polyurethane mixture. However, this two-component curing strategy has many problems. It requires the photocurable prepolymer and the heat-curable component to be packaged and stored separately, and then precisely metered and mixed before use. Not only is the process complex, but it can also lead to incomplete curing and unstable 3D printed product performance due to ratio deviation or uneven mixing. The heat-curable component also has harsh storage conditions and is prone to premature deactivation, increasing material costs and process difficulty. In contrast, single-component dual-curing photosensitive resins integrate photocurable active functional groups and closed heat-curable active functional groups into the same system through molecular structure design. This allows direct 3D printing without pre-mixing, greatly simplifying the 3D printing production process. Furthermore, the closed heat-curable functional groups in the single-component photosensitive resin system have excellent stability at room temperature, effectively preventing spontaneous reactions during storage, extending the shelf life of the photosensitive resin, and reducing the storage and transportation costs of the photosensitive resin. In addition, the single-component photosensitive resin system can achieve rapid shaping and cross-linking density regulation through different curing stages, optimize the mechanical properties and heat resistance of the material, and has more advantages in industrial production. It is suitable for 3D printing application scenarios with strict requirements on process simplification and material consistency. Summary of the Invention

[0003] The present invention aims to provide a single-component 3D printing photosensitive resin, elastomeric material, and preparation method. The photosensitive resin system of the present invention undergoes a dual curing process of light and heat curing to produce an elastomeric material. During the light curing stage, the acrylate double bonds in the photosensitive resin system undergo a cross-linking reaction, allowing the material to rapidly form. During the heat curing stage, the blocked diisocyanate is unblocked by heat and reacts with the amino groups in the acrylic-modified polyamine, resulting in deep chain extension, ultimately producing an elastomeric product with excellent performance.

[0004] The present invention first provides a single-component 3D printing photosensitive resin, which includes the following raw materials in parts by mass:

[0005] 10-25 parts of blocked diisocyanate, 30-70 parts of acrylic modified polyamine, 20-40 parts of reactive diluent, 2-5 parts of photoinitiator;

[0006] The structural formula of the blocked diisocyanate is shown in Formula I:

[0007] Formula I;

[0008] The structural formula of the acrylic acid modified polyamine is shown in Formula II:

[0009] Formula II;

[0010] In formula II, n1=1~20, n2=1~20, n3=1~20.

[0011] Preferably, the reactive diluent is 2-methyl-1,3-propanediol diacrylate.

[0012] Preferably, the photoinitiator is diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide.

[0013] The present invention also provides a method for preparing the above-mentioned single-component 3D printing photosensitive resin, comprising:

[0014] Step 1: adding hexamethylene diisocyanate, phenol, a catalyst and a solvent into a reaction vessel to react to obtain a blocked diisocyanate represented by Formula I;

[0015] Formula I;

[0016] Step 2: Methacrylic acid and hydroquinone are dissolved in a solvent to obtain a monomer solution. Under nitrogen protection, a triamine containing a flexible fatty chain structure and a catalyst are added to a reaction vessel. The reaction system is placed in an ice-water bath and cooled to 0-5°C. The monomer solution is then added dropwise to the reaction vessel. After the addition is complete, the reaction system is naturally heated to room temperature and the reaction is continued for 4-6 hours. After post-treatment, an acrylic acid-modified polyamine represented by Formula II is obtained.

[0017] Formula II;

[0018] In formula II, n1=1~20, n2=1~20, n3=1~20;

[0019] Step 3: Mix the blocked diisocyanate prepared in step 1, the acrylic modified polyamine prepared in step 2, a reactive diluent, and a photoinitiator to obtain a single-component 3D printing photosensitive resin.

[0020] Preferably, the molar ratio of hexamethylene diisocyanate to phenol in step 1 is 1: (2-2.2).

[0021] Preferably, the reaction temperature of step 1 is 60-80° C., and the reaction time is 2-4 hours.

[0022] Preferably, in step 2, the molar ratio of the triamine containing a flexible fatty chain structure to methacrylic acid is 1:(1-1.2).

[0023] The present invention also provides an elastomeric material comprising the above-mentioned single-component 3D printing photosensitive resin.

[0024] The present invention also provides a method for preparing an elastomeric material, comprising:

[0025] Step 1: Place the single-component 3D printing photosensitive resin in the resin tank of the 3D printer and perform light curing to obtain a light-cured product;

[0026] Step 2: thermally curing the photocured product of step 1 to obtain an elastomeric material.

[0027] Preferably, the heat curing in step 2 is preheated in an oven at 80-100° C. for 0.5-2 hours, and then heated to 120-150° C. and maintained for 1-2 hours.

[0028] Beneficial effects of the present invention

[0029] The present invention provides a one-component 3D printing photosensitive resin, an elastomer material and a preparation method. The one-component 3D printing photosensitive resin of the present invention is composed of an acrylic acid modified polyamine, a blocked diisocyanate, a diacrylate reactive diluent and a photoinitiator. In the light curing stage, the acrylate double bonds in the photosensitive resin system undergo a cross-linking reaction, allowing the material to be rapidly formed; in the heat curing stage, the blocked diisocyanate is unblocked by heat and reacts with the amino group in the acrylic acid modified polyamine to undergo deep chain extension, ultimately obtaining an elastomer material product. The dual curing process of the above-mentioned one-component 3D printing photosensitive resin system combines the rapid prototyping advantages of light curing and the deep chain extension advantages of heat curing, so that the finally obtained elastomer material has a higher molecular weight and better mechanical properties. In addition, the blocked diisocyanate in the one-component 3D printing photosensitive resin system has excellent stability at room temperature, and can only be unblocked and exhibit reactive activity under high temperature conditions, and then undergoes a chain extension reaction with the acrylic acid modified polyamine to form a high molecular weight polyurethane elastomer material. Therefore, the single-component photosensitive resin system exhibits excellent stability when stored at room temperature, can avoid the problem of spontaneous curing and deterioration during storage, extend the storage period of the photosensitive resin, relax its storage conditions, and thus significantly reduce the storage and transportation costs and usage complexity of the photosensitive resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the H-NMR spectrum of the blocked diisocyanate of formula I prepared in Example 1 of the present invention;

[0031] Figure 2This is the H-NMR spectrum of the methacrylamide diamine with the structure of Formula II prepared in Example 1 of the present invention;

[0032] Figure 3 is the tensile strength curve of the elastomeric material in Example 1 of the present invention;

[0033] Figure 4 is the tensile strength curve of the elastomeric material in Example 2 of the present invention;

[0034] Figure 5 is the tensile strength curve of the elastomeric material in Example 3 of the present invention;

[0035] Figure 6 is the viscosity change curve of the photosensitive resin in Examples 1 to 3 of the present invention;

[0036] Figure 7 This is the viscosity change curve of the photosensitive resin in Comparative Example 1. DETAILED DESCRIPTION

[0037] The present invention first provides a single-component 3D printing photosensitive resin, which includes the following raw materials in parts by mass:

[0038] 10-25 parts of blocked diisocyanate, 30-70 parts of acrylic modified polyamine, 20-40 parts of reactive diluent, 2-5 parts of photoinitiator;

[0039] The structural formula of the blocked diisocyanate is shown in Formula I:

[0040] Formula I;

[0041] The structural formula of the acrylic acid modified polyamine is shown in Formula II:

[0042] Formula II;

[0043] In formula II, n1=1~20, n2=1~20, n3=1~20.

[0044] According to the present invention, the reactive diluent is preferably 2-methyl-1,3-propanediol diacrylate (MPDDA), and the photoinitiator is preferably diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO).

[0045] The present invention also provides a method for preparing a single-component 3D printing photosensitive resin, which specifically includes:

[0046] Step 1: Add hexamethylene diisocyanate (HDI), phenol, a catalyst, and an anhydrous solvent to a reaction vessel at room temperature and conduct the reaction under nitrogen. The reaction system is preferably slowly heated to 60-80°C and maintained at this temperature for 2-4 hours. During the reaction, the solvent is refluxed through a condenser and stirred continuously to ensure sufficient reaction progress. After the reaction is complete, the system is cooled to room temperature and the toluene solvent is removed by vacuum distillation to obtain a light yellow, viscous blocked diisocyanate represented by Formula I. The catalyst is preferably dibutyltin dilaurate, and the anhydrous solvent is preferably toluene. The molar ratio of hexamethylene diisocyanate to phenol is preferably 1:(2-2.2). The amount of dibutyltin dilaurate catalyst used is preferably 0.3%-0.5% by mass of the hexamethylene diisocyanate. The reaction process is as follows:

[0047]

[0048] Step 2: Methacrylic acid and the polymerization inhibitor hydroquinone are dissolved in a solvent, preferably anhydrous tetrahydrofuran, to obtain a monomer solution, which is transferred to a constant pressure dropping funnel for later use. Under nitrogen, a triamine containing a flexible fatty chain structure and a catalyst are added to the reaction vessel. The reaction system is cooled to 0-5°C in an ice-water bath, and the monomer solution is slowly added dropwise, preferably at a rate of 1-2 drops / second, with the reaction temperature controlled not to exceed 10°C. After the addition is complete, the ice bath is removed, and the reaction system is allowed to naturally warm to room temperature and continue to react for 4-6 hours. After completion of the reaction, post-treatment is preferably performed, wherein the generated triethylamine hydrochloride solid is first filtered out, and the filtrate is washed sequentially with 5% sodium bicarbonate solution and deionized water until neutral. After drying over anhydrous sodium sulfate, the solvent is removed by vacuum distillation to obtain a crude product, which is purified by silica gel column chromatography. The target fraction is collected and concentrated by rotary evaporation, and finally dried in vacuo at 40°C for 24 hours to obtain the target product, methacrylamide diamine, as a pale yellow viscous product. The catalyst is preferably triethylamine, and the ternary amine containing a flexible fatty chain structure is preferably N-(1-(1,1-bis(2-aminopropoxy)ethoxy)prop-2-yl)methacrylamide. The molar ratio of the ternary amine containing a flexible fatty chain structure to methacrylic acid is preferably 1:(1-1.2). The amount of hydroquinone used is preferably 0.5%-1% of the mass of methacrylic acid. The molar ratio of methacrylic acid to the catalyst triethylamine is preferably 1:(1-1.2). The reaction process is as follows:

[0049]

[0050] Step 3: Mix the blocked diisocyanate prepared in step 1, the acrylic modified polyamine prepared in step 2, the reactive diluent and the photoinitiator. The mixing is preferably performed by magnetic stirring to fully mix the components at room temperature until a uniform and transparent photosensitive resin is formed.

[0051] The present invention also provides an elastomeric material comprising the above-mentioned single-component 3D printing photosensitive resin.

[0052] The present invention also provides a method for preparing an elastomeric material, comprising:

[0053] Step 1: Place a single-component 3D printing photosensitive resin in a resin tank of an ultra-high-speed, high-precision 3D printer, and preferably use 405nm ultraviolet light for layer-by-layer exposure and curing to obtain a photocured product, including a structure as shown in Formula III:

[0054] Formula III;

[0055] In formula III, n1=1~20, n2=1~20, n3=1~20.

[0056] The reaction process is as follows:

[0057]

[0058] Step 2: The photocured product formed in step 1 is preferably preheated in an oven at 80-100°C for 0.5-2 hours, and then heated to 120-150°C and maintained for 1-2 hours. During this process, the blocked diisocyanate is unblocked, releasing active isocyanate groups. These active groups undergo a chain extension reaction with the amino groups on the methacrylamide diamine molecular chain in the photocurable network to obtain an elastomeric material having a structure as shown in Formula IV:

[0059] Formula IV;

[0060] In formula IV, n1=1~20, n2=1~20, n3=1~20, n4=5~200.

[0061] The reaction process is as follows:

[0062]

[0063]

[0064] The present invention is further described in detail below with reference to specific examples, in which the raw materials involved are all commercially available.

[0065] Example 1

[0066] 1) At room temperature, hexamethylene diisocyanate (HDI) (16.82 g), phenol (18.82 g), catalyst dibutyltin dilaurate (0.08 g) and anhydrous solvent toluene (100 mL) were added in sequence to a three-necked flask equipped with a thermometer, a mechanical stirrer and a condenser. Under nitrogen protection, the reaction system was slowly heated to 80°C and kept at a constant temperature for 4 hours. During the reaction, the solvent was refluxed through the condenser and stirred continuously to ensure that the reaction was fully carried out. After the reaction was completed, the system was cooled to room temperature, and then the solvent toluene was removed by reduced pressure distillation to finally obtain a light yellow viscous blocked diisocyanate product. The nuclear magnetic spectrum is shown as follows Figure 1 shown.

[0067] 2) Under nitrogen, add N-(1-(1,1-bis(2-aminopropoxy)ethoxy)prop-2-yl)methacrylamide (29.88 g) and triethylamine (12.00 g) as a catalyst to a three-necked flask equipped with a mechanical stirrer, thermometer, and reflux condenser. Separately, dissolve methacrylic acid (10.40 mL) and the polymerization inhibitor hydroquinone (0.12 g) in anhydrous tetrahydrofuran (300 mL) and transfer to a constant-pressure dropping funnel for later use. After cooling the reaction system to 0°C in an ice-water bath, slowly add the monomer solution dropwise at a rate of 1–2 drops / second, maintaining the reaction temperature above 10°C. After the addition is complete, remove the ice bath, allow the reaction system to warm to room temperature, and continue the reaction for 4 hours. After the reaction is complete, filter out the generated triethylamine hydrochloride solid. Wash the filtrate with 5% sodium bicarbonate solution and then deionized water until neutral. After drying over anhydrous sodium sulfate, the solvent was removed by distillation under reduced pressure to obtain a crude product. Purification was performed using silica gel column chromatography, and the target component was collected and concentrated by rotary evaporation. Finally, vacuum drying was performed at 40°C for 24 hours to obtain the target product, methacrylamide diamine, as a light yellow viscous product. The NMR spectrum is shown in FIG. Figure 2 shown.

[0068] 3) Mix photosensitive methacrylic acid diamine (40 g), 2-methyl-1,3-propylene glycol diacrylate (MPDDA) (35 g), photoinitiator diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) (3 g) and the blocked diisocyanate obtained above (23.5 g) to form a uniform and transparent photosensitive resin system.

[0069] 4) Subsequently, the photosensitive resin is placed in the resin tank of an ultra-high-speed, high-precision 3D printer and exposed and cured layer by layer using 405nm ultraviolet light to obtain a photocured product.

[0070] 5) The formed, photocured product is first preheated in an oven at 80°C for 30 minutes, then heated to 140°C and held for 2 hours. During this process, the blocked diisocyanate deblocks, releasing reactive isocyanate groups. These reactive groups then undergo a chain extension reaction with the amino groups on the methacrylamide diamine chains in the photocurable network, yielding an elastomer.

[0071] The tensile strength of the elastomeric material obtained in Example 1 is 30 MPa, and the elongation at break is 229%. The tensile strength curve is shown in FIG. Figure 3 As shown, this is due to the dual curing mechanism, which combines the rapid prototyping advantages of light curing and the deep chain extension advantages of thermal curing, so that the cured resin has a higher molecular weight and excellent mechanical properties.

[0072] Example 2

[0073] 1) At room temperature, hexamethylene diisocyanate (HDI) (16.82 g), phenol (19.76 g), the catalyst dibutyltin dilaurate (0.08 g), and anhydrous toluene (100 mL) were added sequentially to a three-necked flask equipped with a thermometer, mechanical stirrer, and condenser. Under nitrogen, the reaction system was slowly heated to 80°C and maintained at this temperature for 4 hours. During the reaction, the solvent was refluxed through the condenser and stirred continuously to ensure sufficient reaction progress. After the reaction was complete, the system was cooled to room temperature, and the toluene solvent was removed by vacuum distillation to obtain a light yellow, viscous blocked diisocyanate product.

[0074] 2) Under nitrogen, add N-(1-(1,1-bis(2-aminopropoxy)ethoxy)prop-2-yl)methacrylamide (29.88 g) and triethylamine (12.00 g) as a catalyst to a three-necked flask equipped with a mechanical stirrer, thermometer, and reflux condenser. Separately, dissolve methacrylic acid (10.40 mL) and the polymerization inhibitor hydroquinone (0.12 g) in anhydrous tetrahydrofuran (300 mL) and transfer to a constant-pressure dropping funnel for later use. After cooling the reaction system to 0°C in an ice-water bath, slowly add the monomer solution dropwise at a rate of 1–2 drops / second, maintaining the reaction temperature above 10°C. After the addition is complete, remove the ice bath, allow the reaction system to warm to room temperature, and continue the reaction for 4 hours. After the reaction is complete, filter out the generated triethylamine hydrochloride solid. Wash the filtrate with 5% sodium bicarbonate solution and then deionized water until neutral. After drying over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure to obtain a crude product. The product was purified by silica gel column chromatography, and the target fraction was collected and concentrated by rotary evaporation. Finally, the product was dried under vacuum at 40°C for 24 hours to obtain the target product, methacrylamide diamine, as a light yellow viscous product.

[0075] 3) Mix photosensitive methacrylic acid diamine (43.5 g), 2-methyl-1,3-propylene glycol diacrylate (MPDDA) (30 g), photoinitiator diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) (3 g) and the blocked diisocyanate (25 g) obtained above to form a uniform and transparent photosensitive resin system.

[0076] 4) Subsequently, the photosensitive resin is placed in the resin tank of an ultra-high-speed, high-precision 3D printer and exposed and cured layer by layer using 405nm ultraviolet light to obtain a photocured product.

[0077] 5) The formed, photocured product is first preheated in an oven at 80°C for 30 minutes, then heated to 140°C and held for 2 hours. During this process, the blocked diisocyanate deblocks, releasing reactive isocyanate groups. These reactive groups then undergo a chain extension reaction with the amino groups on the methacrylamide diamine chains in the photocurable network, yielding an elastomer.

[0078] The tensile strength of the elastomeric material obtained in Example 2 is 28 MPa, and the elongation at break is 213%. The tensile strength curve is shown in FIG. Figure 4 shown.

[0079] Example 3

[0080] 1) At room temperature, hexamethylene diisocyanate (HDI) (16.82 g), phenol (20.70 g), the catalyst dibutyltin dilaurate (0.17 g), and anhydrous toluene (100 mL) were added sequentially to a three-necked flask equipped with a thermometer, mechanical stirrer, and condenser. Under nitrogen, the reaction system was slowly heated to 80°C and maintained at this temperature for 4 hours. During the reaction, the solvent was refluxed through the condenser and stirred continuously to ensure sufficient reaction progress. After the reaction was complete, the system was cooled to room temperature, and the toluene solvent was removed by vacuum distillation to obtain a light yellow, viscous blocked diisocyanate product.

[0081] 2) Under nitrogen, add N-(1-(1,1-bis(2-aminopropoxy)ethoxy)prop-2-yl)methacrylamide (29.88 g) and triethylamine (12 g) as a catalyst to a three-necked flask equipped with a mechanical stirrer, thermometer, and reflux condenser. Separately, dissolve methacrylic acid (10.40 mL) and the polymerization inhibitor hydroquinone (0.12 g) in anhydrous tetrahydrofuran (300 mL) and transfer to a constant-pressure dropping funnel for later use. After cooling the reaction system to 0°C in an ice-water bath, slowly add the monomer solution dropwise at a rate of 1–2 drops / second, maintaining the reaction temperature above 10°C. After the addition is complete, remove the ice bath, allow the reaction system to warm to room temperature, and continue the reaction for 4 hours. After the reaction is complete, filter and remove the generated triethylamine hydrochloride solid. The filtrate is washed sequentially with 5% sodium bicarbonate solution and deionized water until neutral. After drying over anhydrous sodium sulfate, the solvent is removed by distillation under reduced pressure to obtain a crude product. The product was purified by silica gel column chromatography, and the target component was collected and concentrated by rotary evaporation. Finally, the product was dried in vacuo at 40° C. for 24 hours to obtain the target product, methacrylamide diamine, as a light yellow viscous product.

[0082] 3) Photosensitive methacrylic acid diamine (50g), 2-methyl-1,3-propylene glycol diacrylate (MPDDA) (33.5g), photoinitiator diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) (3g) and the above-obtained blocked diisocyanate (15g) were mixed in a certain proportion to form a uniform and transparent photosensitive resin system.

[0083] 4) Subsequently, the photosensitive resin is placed in the resin tank of an ultra-high-speed, high-precision 3D printer and exposed and cured layer by layer using 405nm ultraviolet light to obtain a photocured product.

[0084] 5) The formed, photocured product is first preheated in an oven at 80°C for 30 minutes, then heated to 140°C and held for 2 hours. During this process, the blocked isocyanate deblocks, releasing reactive isocyanate groups. These reactive groups then undergo a chain extension reaction with the amino groups on the methacrylamide diamine chains in the photocurable network, yielding an elastomer.

[0085] The tensile strength of the elastomeric material obtained in Example 3 is 29 MPa, and the elongation at break is 221%. The tensile strength curve is shown in FIG. Figure 5 shown.

[0086] Storage life test

[0087] The present invention systematically investigates the storage stability of the photosensitive resins prepared in Examples 1-3. Figure 6 As shown, Figure 6The viscosity curves of the photosensitive resins in Examples 1-3 of the present invention show that, under sealed storage conditions at room temperature, all samples exhibit excellent storage stability, with their viscosity remaining essentially constant over time. This excellent performance is attributed to the single-component system design employed in these examples, particularly the chemical blocking of the active isocyanate groups, which effectively prevents side reactions during storage.

[0088] To verify the importance of blocking, the present invention designed a comparative experiment: the blocked diisocyanate in the example was replaced with unblocked hexamethylene diisocyanate (HDI). The specific process is as follows:

[0089] Comparative Example 1

[0090] 1) Under nitrogen, add N-(1-(1,1-bis(2-aminopropoxy)ethoxy)prop-2-yl)methacrylamide (29.88 g) and triethylamine (12 g) as a catalyst to a three-necked flask equipped with a mechanical stirrer, thermometer, and reflux condenser. Separately, dissolve methacrylic acid (10.40 mL) and the polymerization inhibitor hydroquinone (0.12 g) in anhydrous tetrahydrofuran (300 mL) and transfer to a constant-pressure dropping funnel for later use. After cooling the reaction system to 0°C in an ice-water bath, slowly add the monomer solution dropwise at a rate of 1–2 drops / second, maintaining the reaction temperature above 10°C. After the addition is complete, remove the ice bath, allow the reaction system to warm to room temperature, and continue the reaction for 4 hours. After the reaction is complete, filter and remove the generated triethylamine hydrochloride solid. The filtrate is washed sequentially with 5% sodium bicarbonate solution and deionized water until neutral. After drying over anhydrous sodium sulfate, the solvent is removed by distillation under reduced pressure to obtain a crude product. The product was purified by silica gel column chromatography, and the target component was collected and concentrated by rotary evaporation. Finally, the product was dried in vacuo at 40° C. for 24 hours to obtain the target product, methacrylamide diamine, as a light yellow viscous product.

[0091] 2) Photosensitive methacrylic acid diamine (50 g), 2-methyl-1,3-propylene glycol diacrylate (MPDDA) (33.5 g), photoinitiator diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) (3 g) and hexamethylene diisocyanate HDI (15 g) were mixed in a certain proportion to form a uniform and transparent photosensitive resin system.

[0092] 3) Subsequently, the photosensitive resin is placed in the resin tank of an ultra-high-speed, high-precision 3D printer and exposed and cured layer by layer using 405nm ultraviolet light to obtain a photocured product.

[0093] 4) The formed photocured product was first preheated in an oven at 80°C for 30 minutes, and then heated to 140°C and maintained for 2 hours to obtain an elastomer material.

[0094] like Figure 7 The following is a viscosity curve for the photosensitive resin in Comparative Example 1. It can be seen that these unblocked samples exhibited a significant increase in viscosity during storage, ultimately leading to gelation and failure. This phenomenon can be attributed to the chain extension reaction between active isocyanate groups, amino groups, and moisture in the air. These comparative experimental results fully demonstrate the critical role of isocyanate blocking in ensuring the storage stability of photosensitive resins.

Claims

1. A single-component 3D printing photosensitive resin, characterized in that: Calculated by weight, it includes the following raw materials: 10-25 parts of blocked diisocyanate, 30-70 parts of acrylic modified polyamine, 20-40 parts of reactive diluent, 2-5 parts of photoinitiator; The structural formula of the blocked diisocyanate is shown in Formula I: The structural formula of the acrylic acid modified polyamine is shown in Formula II: In formula II, n1=1~20, n2=1~20, n3=1~20.

2. A single-component 3D printing photosensitive resin according to claim 1, characterized in that: The active diluent is 2-methyl-1,3-propylene glycol diacrylate.

3. The single-component 3D printing photosensitive resin according to claim 1, characterized in that: The photoinitiator is diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide.

4. The method for preparing a single-component 3D printing photosensitive resin according to claim 1, characterized in that: include: Step 1: adding hexamethylene diisocyanate, phenol, a catalyst and a solvent into a reaction vessel to react to obtain a blocked diisocyanate represented by Formula I; Step 2: Methacrylic acid and hydroquinone are dissolved in a solvent to obtain a monomer solution. Under nitrogen protection, a triamine containing a flexible fatty chain structure and a catalyst are added to a reaction vessel. The reaction system is placed in an ice-water bath and cooled to 0-5°C. The monomer solution is then added dropwise to the reaction vessel. After the addition is complete, the reaction system is naturally heated to room temperature and the reaction is continued for 4-6 hours. After post-treatment, an acrylic acid-modified polyamine represented by Formula II is obtained. In formula II, n1=1-20, n2=1-20, n3=1-20; The structural formula of the triamine containing a flexible fatty chain structure is as follows: In the above formula, n1=1~20, n2=1~20, n3=1~20; Step 3: Mix the blocked diisocyanate prepared in step 1, the acrylic modified polyamine prepared in step 2, a reactive diluent, and a photoinitiator to obtain a single-component 3D printing photosensitive resin.

5. The method for preparing a single-component 3D printing photosensitive resin according to claim 4, characterized in that: In the step 1, the molar ratio of hexamethylene diisocyanate to phenol is 1:(2-2.2).

6. The method for preparing a single-component 3D printing photosensitive resin according to claim 4, characterized in that: The reaction temperature of step 1 is 60-80° C., and the reaction time is 2-4 hours.

7. The method for preparing a single-component 3D printing photosensitive resin according to claim 4, characterized in that: In the step 2, the molar ratio of the triamine containing a flexible fatty chain structure to methacrylic acid is 1:(1-1.2).

8. An elastomeric material comprising the single-component 3D printing photosensitive resin according to claim 1.

9. The method for preparing an elastomeric material according to claim 8, characterized in that: include: Step 1: Place the single-component 3D printing photosensitive resin in the resin tank of the 3D printer and perform light curing to obtain a light-cured product; Step 2: thermally curing the photocured product of step 1 to obtain an elastomeric material.

10. The method for preparing an elastomeric material according to claim 9, characterized in that: The heat curing in step 2 is to preheat the material in an oven at 80-100° C. for 0.5-2 hours, and then heat the material to 120-150° C. and keep the temperature at that for 1-2 hours.

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